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LIBRARY 
G 


THE 


CYCLOPAEDIA 


OP 


ANATOMY  AND    PHYSIOLOGY 


VOL.  I. 
A— -DEA 

1835-1836 


THE 


CYCLOPAEDIA 


OF 


ANATOMY  AND  PHYSIOLOGY. 


EDITED   BY 

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

\\ 

FELLOW      OF      THE      ROYAL      COLLEGE      OF      PHYSICIANS; 

PHYSICIAN  TO  KING'S  COLLEGE  HOSPITAL  ;    AND  FORMERLY 

PROFESSOR    OF    PHYSIOLOGY   AND    OF    GENERAL  AND    MORBID    ANATOMY    IN    KING'S    COLLEGE, 

LONDON,    ETC.    ETC. 


VOL.  I. 
A DBA 

1835—1836 


LONDON 
LONGMAN,  BROWN,  GREEN,  LONGMANS,  &  ROBERTS. 


QL7 


PREFACE. 


To  collect  a  series  of  Essays  on  all  the  various  subjects  of  Anatomy  and  Phy- 
siology, by  the  co-operation  of  several  Authors,  who,  as  far  as  possible,  should 
be  selected  in  consequence  of  their  special  attention  to,  or  interest  in,  the 
subject-matter  of  the  articles  which  each  would  undertake  to  furnish,  was 
the  object  of  the  Editor  in  projecting  the  "Cyclopaedia  of  Anatomy  and 
Physiology." 

The  successful  inauguration  of  a  similar  work  on  Practical  Medicine, 
which  had  advanced  some  way  prior  to  the  commencement  of  this  Cyclopedia, 
afforded  great  encouragement  to  the  Publishers  and  to  the  Editor  to  prosecute 
their  design. 

The  first  part  was  published  in  1835,  twenty-four  years  ago.  It  was 
then  calculated  that  twenty  parts  would  complete  the  book,  arid  that  not  many 
years  would  have  been  sufficient  for  that  purpose, 

A  glance  at  the  Table  of  classified  Contents  will  show  the  multipli- 
city of  topics  on  which  it  was  proposed  to  treat:  —  Anatomy,  both  as 
it  regards  man  and  all  the  tribes  of  inferior  creatures, — Anatomy  de- 
scriptive,—  Anatomy  physiological  or  histological,  —  Comparative  Anatomy, 
— Morbid  Anatomy,  general  and  special.  To  these  were  to  be  added: 
Physiology  (human  and  comparative)  ;  some  brief  notice  of  Vegetable  Physi- 
ology ;  the  Anatomy  and  Physiology  of  the  different  classes  of  Animals,  in- 
volving, in  many  instances,  much  reference  to  their  Zoology ;  and  lastly  Animal 
Chemistry,  including  the  physiology  of  the  fluids  and  secretions. 
VOL.  i.  a 


PREFACE. 

Numerous  as  were  the  articles  which,  according  to  the  first  plan  of  the 
work,  were  to  have  been  introduced,  it  was  soon  found  indispensable  not  only 
to  add  others  quite  new,  but  also  to  enlarge  considerably  the  space  allotted 
to  each  of  those  which  formed  the  original  catalogue,  and  to  multiply  greatly 
the  number  of  illustrations. 

All  this  was  rendered  necessary  by  the  rapid  strides  which  our  know- 
ledge of  many  subjects  in  Anatomy  and  Physiology  began  to  take  at  the  time 
when  the  earlier  parts  of  the  Cyclopasdia  made  their  appearance.  Perhaps 
there  never  was  greater  activity  of  research  in  any  branch  of  science  during 
a  given  period,  than  that  under  which  the  sciences  of  Anatomy  and  Phy- 
siology advanced  during  the  last  quarter  of  a  century.  Minute  anatomy, 
which  thirty  years  ago  was  crude  and  undigested,  now  takes  very  high  rank 
among  the  various  branches  of  Natural  Knowledge.  During  these  years  every 
tissue  has  been  scrutinised ;  many  obscure  points  have  been  cleared  up  ; 
much  that  was  wholly  unknown  has  been  brought  to  light.  The  additions  to 
our  knowledge  of  Anatomy,  although  there  is  yet  ample  room  for  fresh  dis- 
coveries, have  given  a  totally  new  phase  to  Physiology.  From  being  little 
more  than  a  series  of  vague  and  ill-founded  hypotheses,  scarcely  deserving  even 
that  name,  it  has  become  a  well-arranged  science,  embracing  a  vast  amount 
of  clearly  defined  facts,  which,  at  once,  form  a  solid  basis  for  a  superstructure 
of  sound  theory,  and  throw  much  light  upon  the  various  processes  of  animal 
and  vegetable  life. 

It  was  the  constant  aim  of  the  Editor,  where  it  was  possible,  to  secure  the 
assistance  of  Contributors  who  would  be  likely  to  make  original  investiga- 
tions, and  to  employ  new  researches  for  furnishing  the  materiel  of  their  articles. 
Whilst  it  is  thankfully  acknowledged,  that  in  many  instances  the  Editor's  most 
sanguine  hopes  were  fully  attained,  it  is  not  less  true  that  he  was  sometimes 
disappointed,  and  that  much  delay  of  publication  and  apparent  breach  of  faith 
took  place.  A  few  completely  failed  to  fulfil  their  engagements,  without  any 
assignable  reason;  others  were  unavoidably  prevented  from  so  doing.  In 
several  instances  the  articles  were  not  completed  at  the  stipulated  time.  For 
some  of  these  the  Editor  was  content  to  wait,  notwithstanding  that  by  so 
doing  the  immediate  sale  of  the  book  was  injured,  and  the  Editor  himself 
exposed  (with  apparent  justice)  to  charges  of  violation  of  promises.  But,  in 
the  particular  cases  referred  to,  the  Editor  knew  that  delay  in  the  comple- 


PREFACE. 

tion  of  the  articles  was  caused  by  an  earnest  wish  on  the  part  of  the  Authors 
to  do  ample  justice  to  their  subjects,  and  a  praiseworthy  scrupulousness  in 
recording  facts  which  they  had  not  verified  by  actual  observation. 

To  this  it  must  be  added,  that  for  a  considerable  period  the  continuance 
of  the  work  was  jeopardised,  and  its  publication  wholly  suspended  for  two 
years,  by  the  death,  in  rapid  succession,  of  the  leading  partners  of  the 
publishing  firm  under  whose  auspices  the  work  was  conducted,  prior  to  its 
passing  into  ihe  hands  of  its  present  publishers,  the  Messrs.  Longman. 

Nor  will  the  Editor  attempt  to  shield  himself  from  blame  as  regards  the 
tardy  completion  of  the  Cyclopaedia.  He  is  quite  ready  to  confess  that,  in 
other  hands  than  his  own,  it  would  have  been  long  since  finished.  He  is  con- 
scious that  he  has  been  often  dilatory,  sometimes  vacillating,  occasionally 
appalled  by  the  magnitude  of  the  undertaking,  and  by  the  knowledge  of 
the  inadequacy  of  his  powers  to  carry  it  on  to  a  close.  At  the  same  time, 
in  self-defence,  he  feels  bound  to  plead  that,  soon  after  the  publication  of  the 
first  two  or  three  parts  of  the  work,  certain  onerous  duties  devolved  upon 
him,  which  greatly  curtailed  the  amount  of  leisure  available  for  literary 
pursuits.  In  the  first  place,  he  was  called  upon,  at  short  notice,  to  deliver 
a  lengthened  course  of  Lectures  on  Anatomy  and  Physiology  of  a  kind  quite 
new  in  this  country,  both  as  regards  extent  and  nature,  which  demanded  a 
large  amount  of  study  and  of  personal  inquiry  and  investigation ;  soon 
afterwards  was  added  the  responsible  office  of  a  Hospital  Physician  and 
a  Teacher  of  Clinical  Medicine;  these  were,  at  no  long  interval,  followed  by 
professional  engagements,  which,  although  not  more  responsible,  created  more 
urgent  and  imperative  claims  upon  his  time  and  attention.  With  all  these 
demands  upon  him,  it  will  not  excite  surprise  that  literary  work  often  became 
abandoned  or  postponed. 

At  length,  "  per  varios  casus  et  tot  discrimina  rerum,"  the  period  of  com- 
pletion has  arrived.  And  the  Editor,  while  he  is  impressed  with  a  deep  sense 
of  gratitude  that  his  own  health  and  life  have  been  spared  till  the  completion 
of  the  book,  acknowledges,  with  thankfulness  and  pride,  the  invaluable  aid 
which  he  has  obtained  from  all  quarters.  He  looks  back  with  much  of  the 
same  feelings  which  fill  the  mind  of  an  architect  who  has  projected  a  large 

a  2 


PREFACE. 

building  requiring  for  its  completion  a  long  series  of  years.  While  the  original 
design,  as  well  in  its  defects  as  in  its  merits,  is  due  to  himself,  he  is  conscious 
how  little  he  has  had  to  do  in  supplying  the  materials,  and  completing  the 
details  of  the  building.  For  these  he  has  trusted,  and  not  in  vain,  to  a  body  of 
collaborateurs,  among  whom  he  is  proud  to  reckon  many  of  the  first  scien- 
tific men  both  in  this  country  and  in  Europe.  How  efficiently  this  work  has 
been  done,  it  is  not  for  the  Editor  to  say,  but  he  deems  himself  justified  in 
affirming  that,  for  years  to  come,  this  Cyclopaedia  will  furnish  a  well-stocked 
field  for  reference  to  the  student  of  Anatomy  and  Physiology. 

It  is  remarkable  how  few  of  the  members  of  this  little  phalanx  of 
contributors  have  failed  to  see  the  completion  of  the  work  !  Nevertheless, 
we  have  to  deplore  some  serious  losses ;  and  the  Editor  trusts  he  may  be 
pardoned  for  offering  a  passing  tribute  to  the  memory  of  some  of  the  more 
distinguished  among  them. 

Foremost  among  these,  although  but  recently  removed  from  amongst  us,  was 
the  late  Dr.  MARSHALL  HALL,  who  furnished  articles  on  the  (to  him)  favourite 
subjects,  HYBERNATION,  IRRITABILITY.  x  Although  a  veteran  in  science,  he  had 
finished  his  career  before  he  had  reached  the  ordinary  limits  of  human  life. 
To  large  gifts  of  natural  genius  he  added  an  indomitable  industry  and  perse- 
verance. His  name  must  always  occupy  a  prominent  position  in  the  annals 
of  Physiology,  by  reason  of  the  active  and  highly  successful  part  which  he 
took  in  advancing  our  knowledge  of  the  Physiology  of  the  Nervous  System, 
and  in  promoting  its  application  to  the  investigation  of  Pathology  and  the 
diagnosis  and  treatment  of  disease ;  and  the  extremely  ingenious  speculations 
and  hypotheses  which  he,  from  time  to  time,  suggested  for  the  explanation 
of  various  natural  and  morbid  phenomena.  The  manner  in  which  his  almost 
latest  hours  were  employed  in  applying  physiological  knowledge  to  the 
treatment  of  asphyxia  shows  how  little  it  could  have  been  said  of  him, 
"  Superfluous  lags  the  veteran  on  the  stage." 

Still  more  recently,  another  veteran,  especially  distinguished  in  anatomical 
science,  has  fallen  while  actually  in  the  ranks.  Professor  HARRISON,  having 
been  during  the  previous  day  engaged  in  the  duties  of  his  chair,  rapidly  suc- 
cumbed, in  the  course  of  a  night,  under  an  apoplectic  seizure.  For  forty 
years  and  upwards  he  maintained  the  highest  reputation  as  a  Teacher.  At 


PREFACE. 

a  time  of  life  long  subsequent  to  that  at  which  most  men  seek  repose  from 
such  labour,  he  was  as  fresh,  clear,  full,  and  impressive,  in  teaching  ana- 
tomy, at  once  the  most  elementary  and  the  most  important  of  the  studies 
accessory  to  medicine,  as  in  his  early  days. 

The  celebrated  discoverer  of  Endosmose,  H.  DUTROCIIET,  lived  to  the 
ripe  age  of  seventy-one.  The  article  on  that  subject  in  this  work  was  the 
contribution  of  his  own  pen.  It  contains  a  summary  of  his  views  up  to  the 
time  of  its  publication.  Dutrochet's  discovery  has  the  most  interesting  and 
important  bearing  upon  the  application  of  physical  laws  to  the  illustration  of 
various  processes  of  living  organisms.  It  gave  the  clue  to  the  elucidation  of 
many  obscure  points  in  the  physiology  of  animals  and  plants,  and  took  a  lead 
in  directing  the  minds  of  Physiologists  away  from  abstract  and  fruitless 
speculations  concerning  the  nature  of  Life,  into  the  true  path  of  inquiry  as  to 
the  dependence  of  vital  phenomena  on  chemical  and  physical  laws. 

The  value  of  this  discovery  is  enhanced  by  the  recent  researches  of 
Mr.  GRAHAM,  which  have  developed  the  laws  of  Osmose  (to  use  his  more 
concise  and  comprehensive  designation),  and  have  shown  the  intimate  con- 
nexion of  osmotic  with  chemical  action.  Further  experiments  on  the  osmotic 
phenomena  of  living  animals  and  plants,  assisted  by  the  additional  light  ob- 
tained from  Mr.  Graham's  researches,  can  scarcely  fail  to  lead  to  important, 
practical  results,  both  in  Physiology  and  Pathology. 

The  loss  of  NEWPORT  was  a  heavy  blow  to  Physiology.  A  man  of  his 
skill  as  a  dissector  and  observer  of  that  large  and  most  interesting  tribe,  the 
Insects,  could  ill  be  spared.  The  combination  of  such  manual  dexterity  and 
of  so  much  acuteness  of  observation  as  Newport  displayed  is  rarely  met  with. 
His  investigations  embraced  at  once  the  most  delicate  anatomical  analyses  and 
the  deepest  questions  of  physiology.  The  article  INSECTA,  contributed  by 
him  to  this  work,  is  perhaps  the  most  comprehensive  account  extant  of  the 
anatomy  and  physiology  of  this  class  of  invertebrate  animals.  Newport  was 
cut  down  in  the  prime  of  life,  when,  after  many  struggles  and  difficulties 
his  merits  were  becoming  recognised,  and  the  value  of  his  researches  appre- 
ciated. There  can  be  no  doubt,  had  health  and  life  been  given  him,  he  would 
have  largely  extended  our  knowledge  of  this  branch  of  Comparative  Anatomy 
and  Physiology. 


PREFACE. 

Of  not  less  promise,  in  a  still  wider  field  of  research,  was  JOHN  REID,  who 
for  a  few  years  before  his  early  removal  under  a  painful  and  tedious  disease, 
filled  the  chair  of  Medicine  at  the  University  of  St.  Andrew's,  a  position  in 
which  his  great  powers  had  but  a  limited  scope.  Reid  was  one  of  those  men 
who  are  content  to  take  nothing  for  granted  which  it  was  at  all  in  their 
power  to  examine  for  themselves.  His  admirable  investigation  of  the  Anatomy 
and  Physiology  of  the  Eighth  Pair  of  Nerves  is  a  model  of  anatomical  and 
physiological  research,  scarcely  equalled  and  not  surpassed  by  any  similar 
essay  of  recent  or  remoter  times.  His  articles,  HEART  and  RESPIRATION,  in 
this  Cyclopaedia,  bear  ample  testimony  to  his  scientific  character,  and  well 
sustain  the  high  reputation  he  had  acquired  even  at  a  very  early  age. 

The  late  venerable  Dr.  BOSTOCK,  who  died  at  an  advanced  age,  belonged 
to  a  different  school  of  Physiologists  from  those  already  referred  to.  No  man 
was  more  remarkable  for  the  patience  and  depth  of  his  literary  researches. 
Conscientious  almost  to  a  fault,  he  has  left  a  scrupulously  faithful  record  of  all 
that  was  done  in  Physiology  up  to  the  time  at  which  he  wrote,  affording  to 
those  who  take  an  interest  in  that  branch  of  inquiry  an  impartial  historical 
review  of  the  progress  of  science.  From  the  great  erudition  and  sound 
judgment  of  this  excellent  man,  the  Editor  derived  many  valuable  hints  in 
the  first  stages  of  the  Cyclopedia,  in  the  plan  and  early  progress  of  which  he 
was  pleased  to  take  a  lively  interest. 

Born  a  British  subject,  the  late  W.  F.  EDWARDS  (also  a  veteran  in  science 
although  he  had  by  no  means  attained  a  great  age)  had  spent  most  of  his  life 
in  France  and  followed  his  Physiological  pursuits  there.  His  principal  re- 
searches were  directed  to  the  observation  of  the  influence  of  various  physical 
agents  upon  the  phenomena  of  Life,  and  the  investigation  of  the  chemical 
changes  which  occur  in  some  of  the  most  important  and  recondite  vital  pro- 
cesses. Many  of  his  Essays,  which  were  at  first  published  as  detached 
Papers,  were  afterwards  collected,  and  formed  his  well-known  work  on  the 
"  Influence  of  Physical  Agents  upon  Life."*  Dr.  Edwards's  researches,  whilst 
they  determined  many  new  and  highly  interesting  facts,  were  especially  valu- 
able as  promoting  more  philosophical  views  of  life  than  those  which  referred 
all  vital  phenomena  to  the  influence  of  a  hypothetical  entity. 

*  Translated  into  English  by  Drs,  Hodgkin  and  Fisher,  an.  1832. 


PREFACE 

An  important  article  on  Animal  Chemistry  in  this  Cyclopedia  (PROTEINE) 
was  contributed  by  a  young  and  rising  chemist,  JOHN  E.  BOWMAN,  whose  brief 
career  sufficed  to  impress  his  friends  with  a  strong  sense  of  the  serious  loss 
which  society  and  science  experienced  by  his  early  removal.  His  acute  and 
well-cultivated  intellect  would  have  done  much  for  chemistry  had  his  life 
been  prolonged,  or  had  he  even  enjoyed,  during  its  short  span,  an  ordinary 
amount  of  health.  But  his  last  few  years  were  greatly  marred  in  their  use- 
fulness by  a  singular  chronic  malady,  which  slowly  undermined  his  vital 
powers,  and  greatly  limited  his  ability  for  active  exertion,  whether  bodily  or 
mental.  Nevertheless,  he  has  left  two  works  which,  although  of  small  size, 
are  of  considerable  practical  utility  to  the  chemical  student ;  the  one  devoted 
to  practical  chemistry,  the  other  to  chemistry  in  its  application  to  practical 
medicine. 

The  Editor  takes  this  opportunity  of  acknowledging  his  obligations  to 
gentlemen  who,  at  different  periods,  rendered  him  the  most  efficient  assistance 
in  superintending  the  passing  of  the  work  through  the  press,  and  in  other 
matters  connected  with  his  province. 

Dr.  ROBERT  WILLIS,  formerly  of  London,  now  extensively  engaged  in 
medical  practice  at  Barnes  in  Surrey,  for  many  years  took  an  active  part 
in  the  superintendence  of  the  printing  of  the  work,  and  contributed  largely 
to  the  Bibliography  appended  to  most  of  the  articles,  as  he  was  so  well 
qualified  to  do  by  his  extensive  knowledge  of  books.  Dr.  Willis  also  con- 
tributed the  article  ANIMAL.  Upon  his  retirement,  the  Editor  derived 
similar  valuable  assistance  from  his  friend  and  former  pupil,  Mr.  S.  ROOD 
PITTARD,  who  also  contributed  several  articles.  And,  subsequently,  Dr, 
HYDE  SALTER,  now  well-known,  and  of  deservedly  high  reputation  as  a 
Physiologist  and  Physician,  kindly  afforded  his  aid  in  the  same  way,  as  well 
as  by  his  valuable  contributions  of  the  articles  PANCREAS  and  TONGUE. 

This  seems  the  fitting  place  to  state  that  it  has  been  found  necessary,  in 
a  few  instances,  to  depart  from  the  strict  alphabetical  arrangement,  either  by 
placing  articles  under  names  not  commonly  used,  or  by  clubbing  together  two 
or  more  subjects,  to  which  it  would  appear,  at  first,  more  natural  to  have  de- 
voted separate  articles.  The  necessity  for  such  modifications  arose  out  of 


PREFACE. 

contingencies  to  which  all  works  are  liable,  when  they  are  published  in  Parts, 
and  dependent  for  regularity  of  publication  on  the  punctual  contribution  of  the 
various  articles.  Where  such  punctuality  could  not  be  obtained,  and  where  it 
was  found  absolutely  necessary  to  curtail  delay,  the  changes  above  alluded  to 
were  adopted  as  a  matter  of  necessity  rather  than  of  choice.  Thus,  Ear  is 
referred  to  HEARING,  ORGAN  OF;  Kidney  to  REN.  The  union  of  certain 
articles  together  under  one  heading  was  sometimes  found  both  convenient 
for  treating  the  subjects,  and  economical  of  space.  Thus,  the  Anatomy  of 
the  Brain  was  conveniently  associated  with  that  of  the  Spinal  Cord,  and  will 
be  found  under  NERVOUS  CENTRES  ;  that  of  the  Intestinal  Canal  under 
STOMACH  AND  INTESTINAL  CANAL  (Dr.  Brinton)  ;  and  that  of  the  Ovary  in  the 
elaborate  article  of  Dr.  Farre,  UTERUS  AND  ITS  APPENDAGES.  SEROUS  AND 
SYNOVIAL  MEMBRANES  have  been  treated  of  under  one  heading,  from  the  close 
analogy  of  their  structure ;  and  Hairs,  Nails,  Skin,  &c.,  are  described  under  the 
general  title  TEGUMENTARY  ORGANS. 

It  was  found  absolutely  necessary,  owing  to  difficulties  which  otherwise 
must  have  completely  prevented  the  completion  of  the  work,  to  place  several 
articles  in  a  supplementary  volume,  regardless  of  strict  alphabetical  arrange- 
ment. But  it  is  hoped  that  for  this,  as  well  as  the  other  departures  from  the 
strict  Encyclopaedic  form,  compensation  will  be  found  in  the  various  Indices, 
and  in  the  Table  of  Classified  Contents. 


26  Brook  Street,  Grosvenor  Square,  London, 
Jan.  1859. 


CLASSIFIED    CONTENTS 


THE  CYCLOPEDIA  OF  ANATOMY  AND  PHYSIOLOGY. 


HUMAN  ANATOMY,  DESCKIPTIVE. 


Abdomen Dr.  Todd    

Ankle-joint  Dr.  Brenan 

Aorta    Dr.  Hart 


Vol.  Page 
i.  1 

i.     151 
i.     187 


Arm,    Muscles   of' 
the 


Dr.  Hart i.    219 


Articulation  .........  Dr.  Todd  ............ 

Axillary  Artery  ...  Dr.  Hart  ............ 

Azygos  ...............  Dr.  Harrison  ...... 

Bladder  ...............  Dr.  Harrison  ...... 

Brachial  Artery  ...  Dr.  Hart  ............ 

Brain.     See  Nervous  Centres. 

Carotid  Artery  ......  Dr.  Hart  ............ 

Cranium   ............  J.  Malyn,  Esq.    ... 

Diaphragm  .........  Dr.  Benson  ......... 

Ear.     See  Hearing,  Organ  of. 

Eighth  Pair  of  Nerves.     See  Glosso- 

pharyngeal  ;     Par   Vagum  ;    Spinal 

Accessory. 
Elbow-joint  .........  Dr.  Hart  ............ 

Extremity     .........  Dr.  Todd     ......... 

Eye   ..................  Dr.  Jacob   ......... 

Femoral  Artery  ...  Dr.  Alcock  ......... 

Fibular  Artery  ......  Dr.  Todd     ......... 

Fifth  Pair  of  Nerves  Dr.  Alcock  ......... 

Foetus    ...............  Dr.  Montgomery... 

Foot,    Bones    and1)  _ 

lf  Dr.  Todd     ......... 

Joints  of  the       J 

Fourth     Pair     ofi 

}  Dr.  Alcock  ......... 

Nerves  J 

Generation,       Or-  -^  T.    Rymer  Jones,  -\ 
gans  of  J      Esq.  J 

Glosso-pharyngeal 

,T 
Nerve 


„ 

Dr.  Reid 


Hand,  Bones  and 

Joints  of  the 
VOL.  i. 


Dr.  Todd. 


i.  246 

i.  363 

i.  364 

i.  376 

i.  465 

i.  482 

i.  724 

ii.  1 


ii.  65 

ii.  154 

ii.  171 

ii.  235 

ii.  267 

ii.  268 

ii.  316 

ii.  338 

ii.  370 

ii.  406 

ii.  494 

ii.  505 


Hand,  Muscles  of  "i  Bishop    MacDou- 

the  J      gall 

Hearing,  Organ  of     T.  W.  Jones,  Esq. 

Heart    Dr.  Reid 

Heart,      Arrange-  -» 

ment  of  the  Fi-  \H.  Searle,  Esq.  ... 

bres  of  the          J 

Hip-joint  H.  Hancock,  Esq. 

Iliac  Arteries  Dr.  Alcock  

Innominata  Arteria  H.  Hancock,  Esq. 
Kidney.     See  Ren. 

Knee-joint    A.  Higginson,  Esq. 

Lachrymal  Organs    T.  W.  Jones,  Esq. 

Larynx J.  Bishop,  Esq.  ... 

Leg,  Muscles  of. A.T.S.  Dodd,  Esq. 

Liver E.  Wilson,  Esq.  ... 

Mammary  Glands     S.  Solly,  Esq 

Mucous  Membrane    W.  Bowman,  Esq. 

Nervous  Centres  ...  Dr.  Todd 

Ninth      Pair      of-| 

Nerve,  }*•****..- 

Nose J.  Paget,  Esq 

(Esophagus  Dr.  G.  Johnson  ... 

Optic  Nerves    Dr.  Mayne 

Orbit Dr.  G.  Johnson  ... 

Pacinian  Bodies  ...    W.  Bowman,  Esq. 

Pancreas  Dr.  Hyde  Salter ... 

Par  Vagum Dr.  J.  Reid 

Pelvis    John  Wood,  Esq. 

Penis E.  Wilson,  Esq. ... 

Perineum Dr.  Mayne 

Peritoneum  S.  R.  Pittard,  Esq. 

Pharynx  W.  Trew,  Esq.   ... 

Pleura S.  R.  Pittard,  Esq. 

Prostate    J.  Adams,  Esq.  ... 


Vol.  Page 

[  ii.  519 

ii.  529 

ii.  577 

ii.  619 

ii.  776 

ii.  827 

ii.  850 

iii.  44 

iii.  78 

iii.  100 

iii.  137 

iii.  160 

iii.  245 

iii.  484 

iii.  712 

iii.  721 

iii.  723 

iii.  758 

iii.  762 

iii.  782 

iii.  876 

*.  81 

iii.  881 

s.  114 

iii.  909 

iii.  919 

iii.  935 

iii.  945 

iv.  1 

iv.  146 


CLASSIFIED  CONTENTS. 


••.  Thos.  Williams    s.    258 


Vol.  Page 
Radial  Artery Dr.  Brinton    iv.    221 

Radio-ulnar  Arti-T  _ 

\Dr.  Brinton    iv.    228 

culation  J 

Ren  Dr.  Johnson     iv.    231 

Respiration,      Or- 
gans of 

Salivary  Glands  ...  N.  Ward,  Esq.    ...  iv.    422 
Scrotum    Dr.  Brinton iv.    438 

Serous  and  Syno-1  ^ 

^  J        \Dr.  Brinton iv.    511 

vial  Membranes  J 

Sesamoid  Bones  ...  S.  R.  Pittard,  Esq.  iv.    541 
Seventh    Pair    °^T  n     7?  •  / 
Nerves  J 

Shoulder-joint Dr.  M( Dowel  iv.    571 

Sixth  Pair  of  Nerves  Dr.  Brinton iv.    621 

Spinal    Accessory^ 

>  Dr.  John  Reid iv.    745 

Nerve  J 

Spinal  Nerves  N.  Ward,  Esq.    ...  iv.    750 

Spleen Professor  Kolliker     i v.    771 

Stomach  and  In- 
testinal Canal 


\Dr.Bri 


Brinton    s.    293 


Subclavian  Arteries  Dr.  MlDowel 

Supra-renal    Cap-~i  _ 

\  Prof.  Heinrich  Frey 
sules  J 

Sympathetic  Nerve   Dr.  Drummond  ... 

Temporo-Maxil-    -» 

lary      Articula-  I  S.  R.  Pittard,  Esq. 
tions  J 

Testicle T.  B.  Curling,  Esq. 

Thorax Dr.  Hutchinson  ... 

Thymus  Gland Dr.  Handheld  Jones 

Thyroid  Gland     ...  Dr.Handfield Jones 

Tibio-fibular    Ar- 
ticulations 

Tongue Dr.  Hyde  Salter  ... 

Urethra John  Adams,  Esq. 

Uterus  and  its  Ap- 1  _ 

"    \  Dr.  Arthur  Farre 
pendages  J 

Venous  System     . . .  Dr.  M' Dowel 

Vesicula  Prostatica  Prof.  Leuckhardt 
Vesiculse  Seminales  S.  R.  Pittard,  Esq. 
Wrist-joint  Dr.  M' Dowel 


Dr.  M'Dowel 


Vol.  Page 
iv.  814 

iv.  827 
s.  423 

iv.    937 

iv.  976 
iv.  1016 
iv.  1087 
iv.  1102 

iv.  1118 

iv.  1120 
iv.  1244 

s.  545 

iv.  1403 
iv.  1415 
iv.  1429 
iv.  1505 


HUMAN  ANATOMY,  SURGICAL  OR  TOPOGRAPHICAL. 

147     Fore-arm,  Muscles, 

173  and  Regions  of  / 

216  Gluteeal  Region    ...  A. T.  S.  Dodd,Esq.    ii. 

358     Groin,  Region  of  the  Dr.  Todd ii. 

367     Hand.  Regions  ofl  _          ,.     _.        „  .. 
[•  Bishop  Mac  Dougall  u. 

746     Leg,  Regions  of  the  A.  T.  S.  Dodd,  Esq.  iii. 

Neck,  Muscles  and  i   _ 

}J.  Simon,  Esq.    ...  in. 
62        Regions  of  the    J 

207  Parotid  Region  ...  Dr.  G.Johnson...  iii. 
Popliteal  Region  ...  W.  Trew,  Esq.  ...  iv. 
Scapular  Region  ...  Dr.  M' Dowel iv. 


Ankle,  Region  of  the  Dr.  Brenan i. 

Anus R.  Harrison,  Esq.  i. 

Arm Dr.  Hart i. 

Axilla  Dr.  Benson i. 

Back Dr.  Benson i. 

Cranium,  Regions  -j 

and  Muscles  oflz>r.  Todd i. 

the 

Elbow,  Region  of  the  Dr.  Hart. ii. 

Face R.  Partridge,  Esq.  ii. 

Foot,  Regions  arid 

Muscles  of 


\A.T.S.Dodd,Esq.    ii.    350 


361 

500 
503 

523 

126 
561 

902 
60 
433 


ANATOMY,  GENERAL  OR  PHYSIOLOGICAL. 


Adipose  Tissue Dr.  Craigie i.  56 

Artery  Dr.  Hart i.  220 

Bone Dr.  Benson i.  430 

Bursas  Mucosae Dr.  Brenan i.  467 

Cartilage  Dr.  Benson i.  495 

Cavity  Dr.  Todd i.  500 

Cellular  Tissue R.D.Grainger,Esq.  i.  509 

Cilia Dr.  Sharpey    i.  606 

Erectile  Tissue Dr.  Hart ii.  144 

Excretion Dr.  Alison  ii.  147 

Fascia  Dr.  Todd ii.  229 

Fibro-cartilage. Dr.  Todd ii.  260 


Fibrous  Tissue     ...  R.D. Grainger, Esq.    ii.  263' 

Ganglion R.D.Grainger,Esq.    ii.  371 

Gland R.D. Grainger,Esq.    ii.  480 

Lymphatic    S.  Lane,  Esq iii.  205 

Membrane    Dr.  Todd     iii.  331 

Meninges Dr.  Todd iii.  331 

Muscle W.  Bowman,  Esq.    iii.  506 

Nerve    Dr.  Todd iii.  591 

Nervous  System  ...  Dr.  Todd iii.  585 

Osseous  Tissue    ...  J.  Tomes,  Esq.    ...  iii.  847 

Skeleton   Jos.  Maclise,  Esq.    iv.  622 

Vein 5.  J.  A.  Salter,  Ef<q.  iv.  1367 


CLASSIFIED  CONTENTS. 


ANATOMY,  ABNORMAL  AND  MORBID. 


Vol.  Page 

Adhesion B.  Phillips,  Esq....  i.  49 

Ankle-joint  It.  Adams,  Esq.  ...  i.  154 

Artery  W.  H.  Porter,  Esq.  i.  226 

Bladder B.  Phillips,  Esq....  i.  389 

Blood    Dr.  Babinyton     ...  i.  415 

Bone W.  H.  Porter,  Esq.  i.  438 

Cicatrix A.T.S.Dodd,Esq.  i.  602 

Cirronosis Dr.  Todd i.  694 

Cyst R.  Phillips,  Esq....  i.  787 

Elbow-joint  R.  Adams,  Esq.  ...  ii.  67 

Foot A.T.S.Dodd,Esq.  ii.  347 

Hand     R.  Adams,  Esq.  ...  ii.  510 

Heart Dr.  Todd    ii.  630 

Hermaphroditism...  Dr.  Simpson    ii.  684 

Hernia  W.  H.  Porter,  Esq.  ii.  738 

Hip-joint  JR.  Adams,  Esq.  ...  ii.  780 


Hypcrrcmia       and  "I 
Anaemia  J 

Hypertrophy    and 
Atrophy , 

Knee-joint     JR.  Adams,  Esq.  ...  iii. 

Larynx W.  H.  Porter,  Esq.  iii. 

Lymphatic  System    Dr.  Todd    iii. 

Nervous  Centres  ...  Dr.  Todd     iii. 

Products,   Adven- 
titious 


Vol.  Pago 


Dr.  Todd...,  .    ii.    825 


Dr.  Todd    .  .    ii.    826 


48 
114 
232 
712 

I  Dr.  Wolshe iv.      71 


Shoulder-joint R.  Adams,  Esq.  ...  iv.    577 

Softening  and  In-")  _ 

\  Dr.  P.  M.  Duncan  iv.    703 
duration  J 

Teratology    Professor  Vrolik  ...  iv.    942 

Wrist-joint    R.  Adams,  Esq.  ...  iv.  1508 


ANATOMY,  COMPARATIVE. 


Chyliferous  System   Dr.  Grant   i. 

Digestive  Canal    ...  Dr.  Grant  ii. 

Lymphatic      and  l 

>  S.  Lane,  Esq. 
Lacteal  System  J 

Muscular  System...  Prof.  It.  Jones  ...    iii. 
Nervous  System  ...  J.  Anderson,  Esq.     iii. 


600 
27 

iii.  205 

530 
601 


Osseous  System    ...  Prof.  R.  Jones 

Shell Dr.  Carpenter... 

Teeth    Professor  Owen 

Tegumentary   Or-  "1 

gans  (Hair,  Nails,  I  T.  Huxley,  Esq. 

Feathers,  &c.)      J 


in. 
iv. 

iv. 


820 
556 
864 


*.    473 


ZOOLOGICAL  ANATOMY  AND  PHYSIOLOGY. 


Acalephse Dr.  Coldstream 

Acrita   jR.  Owen,  Esq. 

Amphibia      T.  Bell,  Esq 

Animal  Kingdom      Professor  Grant 

Annelida  Dr.  Milne  Edwards 

Arachnida    Dr.  Audouin 

Articulata Professor  Owen 

Aves R.  Owen,  Esq. 

Carnivora T.  Bell,  Esq. 

Cephalopoda JR.  Owen,  Esq, 

Cetacea M.  F.  Cuvier 

Cheiroptera T.  Bell,  Esq. 

Cirrhopoda   Dr.  Coldstream 

Conchifera    M.  Deshayes 

Crustacea Dr.  Milne  Edwards 

Echinodermata Dr.  Sharpey 

Edentata  T.  Bell,  Esq. 

Entozoa Professor  Owen 

Gasteropoda      T.  R.  J 

Insecta G.  Newport,  Esq. 


n  ...  i. 

35 

.  ...  i. 

47 

i. 

90 

nt    i. 

107 

>ards  i. 

164 

i. 

198 

n  ...  i. 

244 

.  ...  i. 

265 

i. 

470 

.  ...  i. 

517 

i. 

562 

i. 

594 

IM  ...  i. 

683 

i. 

694 

wards  i. 

750 

ii. 

30 

ii. 

46 

°n  ...  ii. 

111 

Esq.  ii. 

377 

Esq.   ii. 

853 

Insectivora    T.  Bell,  Esq ii.  994 

Mammalia    Professor  Owen  ...  iii.  234 

Marsupialia Professor  Owen  ...  iii.  257 

Mollusca  Professor  Owen  ...  iii.  363 

Monotremata    Professor  Owen  ...  iii.  366 

Myriapoda    Prof.  R.  Jones    ...  iii.  545 

Pachydermata Prof.  JR.  Jones    ...iii.  858 

Pisces    Prof.  R.  Jones     ...iii.  955 

Polygastria   Prof.  R.  Jones    ...  iv.  2 

Polypifera Prof.  R.  Jones    ...  iv.  18 

Porifera Prof.  R.  Jones    ...  iv.  64 

Pteropoda Prof.  R.  Jones     ...  iv.  170 

Quadrumana    Professor  Vrolik        iv.  194 

Eeptilia Prof .  R.  Jones     ...  iv.  264 

Rodentia  Prof.  R.  Jones iv.  368 

Rotifera    Dr.  Lankester iv.  396 

rDr.    T.     Spencer  -| 

Ruminantia    <^                                  }  *.  506 

I      Cobbold  J 

Solipeda    Prof.  R.  Jones     ...  iv.  713 

Tunicata  Prof.  R.  Jones iv.  1185 


CLASSIFIED  CONTENTS. 


PHYSIOLOGY. 


Absorption     ... 

Dr  Bostock 

Vol. 
i 

Page 
20 

Dr.  Symonds   

i. 

64 

Albino  ... 

Dr.  Bostock  

i. 

83 

Dr.  Willis    

i 

118 

i. 

257 

Dr.  Allen  Thomson 

i. 

638 

Contractility   

Dr.  Alison  ......... 

i 

716 

Dr.  Symonds    

i. 

791 

Dr.  Bostock    

ii. 

6 

Elasticity 

Dr  Brenan            , 

ii 

55 

Electricity,  Animal 
Endosmosis  

Dr.  Coldstream   ... 
Dr.  Dutrochet    ... 

ii. 
ii 

81 

98 

Dr.  Allen  Thomson 

ii. 

424 

Hearing    

Heat  Animal       ... 

Dr.  Todd  
Dr  W  F  Edwards 

ii. 
ii 

564 

648 

Dr.  Marshall  Hall 

ii. 

764 

iii. 

1 

Dr.  Marshall  Hall 

iii. 

29 

Life  

Dr.  Carpenter  

iii. 

141 

Luminousness,        T 
Animal               J 
Motion,     Animal,  -» 
including  Loco-  i- 
motion               J 

Dr.  Coldstream   ... 
J.  Bishop,  Esq.  ... 

iii. 
iii. 

197 

407 

Dr.  J.  B. 

derson 


San- 


Muscular  Motion...    W.  Bowman,  Esq. 
Nervous  System  ...  Dr.  Todd  ............ 

Nutrition  ............  Dr.  Carpenter  ...... 

Ovum    ...............  Dr.  Allen  Thomson 

Parturition  .........  Dr.  Rigby    ......... 

Pulse  ..................  Dr.  Guy  ............ 

Reproduction.  Ve- 

' 
getable    (Vege-  I 

table  Ovum)       J 
Respiration  .........  Dr.  John  Eeid    ... 

Secretion  ............  Dr.  Carpenter  ...... 

Sensation  ............  Dr.  Todd  ............ 

Sensibility  ............  Dr.  Todd  ............ 

Sleep  ..................  Dr.  Carpenter  ...... 

Smell     ...............  Dr.  Carpenter  ...... 

Symmetry  .....  .  ......  S.  R.  Pittard,  Esq. 

Sympathy  ............  Dr.  Todd  ............ 

Taste  ..................  Dr.  Carpenter  ...... 

Temperament  ......  Dr.  Todd    ......... 

Touch   ...............  Dr.  Carpenter  ..... 

Varieties  of  Man- 


Vol.  Page 
iii.  519 

iii.  720o. 

iii.  741 

s.    1 

iii.  904 
iv.  181 

s.  211 

iv.  325 

iv.  439 

iv.  508 

iv.  510 

iv.  677 

iv.  697 

iv.  845 

iv.  852 

iv.  856 

iv.  935 

iv.  1163 


kind 


Dr.  Carpenter iv.  1294 


Vision       W.W.  Cooper, Esq.  iv.  1436 

Voice    John  Bishop,  Esq.    iv.  1475 


ANIMAL  CHEMISTRY,  PHYSIOLOGY  OF  THE  FLUIDS  AND 

SECRETIONS. 


Acids,  Animal  

W.T.  Brande,  Esq.     i. 
W.  T.  Brande,  Esq.    i. 

47 
55 

Milk  
Mucus  

..  Dr.  G.  O.  Rees  ...  iii. 
..  Dr.  G.  O.  Rees  ...  iii 

358 
481 

Albumen  

W.  T.  Brande,  Esq.     i 

88 

Organic  Analysis. 

..  Dr.  Miller  ...           iii. 

792 

Blood    

404 

Protein  

.  .   Prof.  J  E.  Bowman  iv 

162 

Bile  

W.  T.  Brande,  Esq.     i. 

374 

Saliva    

..  Dr.  Owen  Rees  ..    iv. 

415 

W.T.  Brande,  Esq.     i. 

562 

f  Drs.   Wagner  and  ~)  . 

Fat    

W.T.  Brande,  Esq.    ii. 

231 

1     Leuckhardt         J 

472 

W.  T.  Brande  Esq     ii 

257 

Sweat    

..  Dr.  G.  O.  Rees  ...  iv. 

841 

Gelatin  

W.  T.  Brande,  Esq.    ii 

404 

Synovia    

..  Dr.  G.  O.  Rees  ...  iv. 

856 

Haematosine  

Dr.  G.  O.  Rees...    ii. 

503 

Urine    

..  Dr.  G.  O.  Rees  ...  iv. 

1268 

GENERAL  SUBJECTS. 

Medical  Statistics ....  Dr.  Guy  iv.    801  |  Microscope  Dr.  Carpenter iii.    331 

i  Vital  Statistics Dr.  Guy  iv.  1469 


CONTENTS  OF  THE  FIRST  VOLUME. 


Abdomen.  

Dr.  Todd  
Dr.  Bostock    .... 

Page 
1 
20 

Bladder,  Normal  Ana-  ) 

Page 
Dr.  Harrison  ....  376 

Dr.  Coldstream  .  . 

35 

Bladder,  Abnormal     ^ 

Acids    Animal 

W  T.Brande  Esq 

47 

B.  Phillips,  Esq.  .  388 

Acrita 

R  Owen   ESQ 

47 

Blood  

Dr.  Milne  Edwards  404 

B.  Phillips,  Esq    . 

49 

Blood,  Morbid  Condi-  ) 

W  T  Brande  Esq 

55 

Dr.  Babington    ..  415 

Adipose  Tissue  ...... 

Dr.  Craiffie  . 

56 

Bone  NormalAnatomy 

Dr  Benson,..  .  ..  430 

A°-e  ., 

Dr.  Siiwonds  .... 

64 

Bone,  Pathological      ) 

Dr.  Bostock  

83 

W.H.  Porter,  Esq.  438 

Albumen  

W.  T.  Brande  Esq 

88 

Brachial  Artery      .... 

Dr.  Hart  465 

Amphibia    

T  Bell  Esq    .... 

90 

Animal  Kingdom   <  •  .  . 

Dr.  Grant  

107 

Carnivora    

T.  Bell,  Esq  470 

Animal   .  • 

Dr.  Willis 

118 

Dr.  Hart     482 

Ankle   Region  of  the.  . 

147 

Dr.  Benson  495 

Ankle,  Joint  of  the    .  . 

151 

Cavity  

Dr.  Todd  600 

Ankle-joint,Abnormal  ) 
Condition  of  the  .  .  * 

R.  Adams,  Esq.  .  . 

154 

Cellular  Tissue  

R.D.Grainger,Esq.  509 
R.  Owen   Esq     ..  517 

Annelida                   . 

Dr  Milne  Edwards 

164 

W  T  Brande  Eiq    562 

R.  Harrison    Esq 

178 

Mons.  F.  Cuvier  .  .  562 

Aorta    

Dr.  Hart  
Dr.  Audoitin.    .... 

Ib7 

198 

Cheiroptera  
Chyliferous  System   .  . 

T.  Bell,  Esq  594 
Dr  Grant   600 

Arm  

Dr.  Hart  

216 

A.  T.  S.Dodd  Esq.  602 

Arm   Muscles  of  the   . 

Dr  Hart.. 

219 

Cilia  

Dr.  Sharpey    ....  606 

Artery  

Dr.  Hart  

220 

Dr.  Allen  Thomson  638 

Artery,  Pathological  > 

Dr.  Coldstream  .  .  683 

Conditions  of    .  .  .  .  ' 
Articulate    

W.n.  Porter,  Esq. 
R.  Owen,  Esq.   .  . 

226 
244 

Cirronosis    

Dr.  Todd  694 
M.  Deshayes    ....  694 

Articulation    

Dr.  Todd  

246 

Contractility   

Dr.  Alison   716 

257 

J.  Malyn  Esq.   .  .  724 

Aves  

R.  Owen,  Esq.    .  . 

265 

Cranium,  Regions  and  } 

Dr.  Todd  746 

Axilla  

358 

Muscles  of  the.  .  .  .  * 

Axillary  Artery  ...... 

Dr.  Hart  

363 

Dr.  Milne  Edwards  750 

Dr  Harrison  .... 

364 

Cvst  .  . 

B.  Phillips,  Esq.  .  787 

Back 

367 

Death  

Dr  Symonds  ....  791 

Bile  

W.T  Brande  Esq 

374 

THE 


CYCLOPAEDIA 


ANATOMY  AND  PHYSIOLOGY 


a 

terms 
synoi 


ABDOMEN,  (in  anatomy,)  with  which  the 
terms  venter  and  alvus  are  sometimes  used 
synonymously.  Gr.  ya<mj£.  Germ,  bauch,  un- 
terleib,  hinterleib.  Ital.  ventre,  pancia,  abdo- 
mine:  the  French  anatomists  use  the  word 
abdomen  as  we  do,  and  also  the  term  ventre  as 
we  do  belly ;  also  bas-ventre.  It  is  so  called, 
"  quod  abdi  et  tegi  soleat,  aut  quod  alimenta 
in  eo  abdantur,  aut  intestina  ibi  sint  abdita"* 

The  term  denotes  a  particular  region  and 
cavity  in  a  large  proportion  of  the  animal  series, 
being  found  in  most  of  the  classes  from  Mam- 
malia down  to  Articulata.  It  is  impossible  to 
give  such  a  definition  of  this  region  as  will 
apply  to  all ;  it  appears,  however,  to  have  one 
property  sufficiently  general,  viz.  that  it  con- 
tains in  all  these  classes  more  or  less  of  the 
digestive  organs.  Thus,  to  ascend  from  the 
Articulata : — 

It  is  in  the  class  Insecta  of  the  Articulata  that 
we  find  the  most  defined  region  bearing  this 
name.  This  region  is  the  most  posterior  of  the 
three  portions  into  which  the  body  of  an  insect 
is  divided,  and  is  composed  of  a  series  of  seg- 
ments which  unite  to  form  a  cavity  enclosing 
the  viscera  subservient  to  nutrition,  respiration, 
and  reproduction  ;  it  does  not  contain  any  of  the 
organs  concerned  in  locomotion.  It  is  com- 
posed of  a  series  of  simple  hoops,  united  to 
each  other  by  a  ligamentous  connexion,  which 
allows  the  abdomen  to  be  flexible  or  otherwise, 
according  to  the  closeness  of  the  union  ,f  The 
abdomen  is  united  by  its  anterior  extremity  to 

*  Facciolati,  in  verb. 

t  See  a  very  good  engraving  from  Cams,  of  the 
segments  of  an  insect,  in  Roget's  Uridgewater  Trea- 
tise, vol.  i.  p.  321. 
VOL.  i. 


the  thorax.  (See  INSECTA.)  In  the  Arachnida 
there  is  also  a  similar  division  of  the  body,  to 
which  the  name  of  abdomen  has  been  applied, 
united  in  front  with  the  cephalo-thorax,  and 
separated  from  it  by  a  deep  groove,  which 
leaves  only  a  slender  pedicle  between  them ; 
like  that  of  the  Insecta  it  contains  the  principal 
viscera.  (See  ARACHNIDA.) 

In  all  the  divisions  of  the  Vertebrata  there  is 
an  abdomen .  In  fishes  the  abdomen  is  situated 
towards  the  posterior  extremity  of  the  body, 
and  is  separated  from  the  heart  in  front  by  a 
strong  membrane  analogous  to  the  diaphragm  ; 
it  contains  the  digestive  and  generative  organs. 
In  reptiles  the  abdomen  is  that  region  which 
lies  immediately  anterior  to  the  anus ;  in  many 
classes  it  is  not  separated  from  the  cavity  con- 
taining the  lungs,  so  that  the  lungs,  heart, 
organs  of  digestion  and  generation  are  all  con- 
tained in  one  great  cavity ;  in  the  crocodile, 
however,  a  layer  of  muscular  fibres,  having  the 
appearance  of  a  diaphragm,  covers  the  perito- 
neum,where  it  is  connected  with  the  liver,  so  that 
the  lungs  do  not  project  into  the  abdomen.  In 
birds,  the  abdomen  extends  from  the  posterior 
extremity  of  the  sternum  to  the  anus  ;  it  is,  as 
in  fishes,  separated  from  the  thorax  by  a  mem- 
brane which,  though  not  muscular,  is  analogous 
to  the  diaphragm,  but  is  perforated  so  as  to 
allow  the  air  to  pass  into  the  abdominal  cells. 
In  Mammalia,  the  abdomen  is  placed  between 
the  pelvis  and  thorax,  with  the  former  of  which 
it  is  continuous ;  but  it  is  separated  from  the 
latter  by  the  diaphragm  ;  its  principal  contents 
consist  of  the  digestive  organs,  and  its  size 
varies  in  reference  to  their  respective  degrees  of 
development. 


ABDOMEN. 


ABDOMEN  (in*  huritari  anatomy.)     In  ex- 
amining .the*  Jiuiaatt.  skeleton,  we.  notice  that 
from  Jlte  ajt^Cot'lhertboi^x.to  th£  "inferior  out- 
let of  the  pelvis,  there  exists  one  great  oblong 
excavation.     The   two  superior  fifths   of  this 
cavity  are  separated  from  the  remaining  portion 
in  the  entire  subject  by  a  musculo- tendinous 
lamella,  which,  thrown   into  a  vaulted  form, 
constitutes  the  partition  between  the  cavity  of 
the  thorax  above  and  that  of  the  abdomen  below. 
This  latter  cavity  communicates  inferiorly  with 
the  space  circumscribed  by  the  ossa  innominata, 
denominated  the  cavity  of  the  pelvis ;  nor  is 
there  any  natural  line  of  demarcation  between 
the  two  cavities.     The  communication  between 
the  two  cavities  is  as  free  in  the  recent  subject 
as  it  is  in  the  skeleton,  and  under  various  con- 
ditions the  contents  of  those  cavities  pass  from 
the  one  to  the  other.     A  plane  extended  hori- 
zontally from  the  linea  iliopectinea  on  one  side 
to  the  corresponding  line  on  the  other  would 
constitute  an  artificial  floor  to  the  cavity  of  the 
abdomen,  properly  so  called,  and  a  limit  be- 
tween it  and  the  pelvis;  and  this  artificial  divi- 
sion  of   a   cavity,    naturally  single,  may  be 
useful  in  describing  the  positions  of  viscera,  but 
to  understand  the  functions  of  the  abdomen, 
it  will  be    expedient  to  consider  that  cavity 
and  the  pelvis  as  one.     Some  anatomists  ob- 
ject to  the  use  of  the  term  cavity  as  applied 
to  the  abdomen,  because  no  cavity  can  be  said 
to  exist,  except  in  the  skeleton  or  in  the  evisce- 
rated subject;    neither  can  there  properly  be 
said  to  be  a  cavity  of  the  thorax  or  of  the  cra- 
nium, inasmuch  as  that  cavity  is  obliterated  so 
long  as  the  viscera  are  in  a  state  of  integrity. 
I  apprehend  that   the  objection  is  hypercriti- 
cal, as  it  must  be  evident  that  the  cavity  does 
not  become  apparent  till  the  viscera  have  been 
removed;  nevertheless,  it  is  perfectly  correct 
to  say  that  it  contains  the  viscera,  nor  is  it  in- 
correct to  make  use  of  the  expression  "  anatomy 
of  the  abdominal  cavity,"  to  imply  the  anatomy 
of  its  contents  when  in  their  natural  position. 
Hence,  then,  we  derive  a  natural  subdivision, 
in  treating  the  subject  of  this  article,  into  two 
heads:     1.  the  anatomy  of  the  walls  of  the 
abdomen ;  and,  2.  the  anatomy  of  the  cavity  of 
the  abdomen. 

I.  Of  the  walls  of  the  abdomen. — One  of  the 
most  striking  differences  between  the  abdomen 
and  the  other  great  visceral  cavities  consists  in 
the  small  proportion  of  bone  that  exists  in  its 
walls.  The  osseous  boundaries  of  the  abdomen 
may  be  thus  enumerated :  superiorly,  towards 
the  posterior  and  outer  part,  the  false  ribs; 
posteriorly,  the  lumbar  region  of  the  spine, 
which  by  its  transverse  processes  affords  strong 
points  for  the  attachment  of  muscles,  and  by 
the  bodies  projects  into  the  cavity,  forming 
an  imperfect  septum,  slightly  convex  on  its 
anterior  surface,  and  dividing  the  cavity  into 
two  symmetrical  portions.  Inferiorly,  the  alse 
of  the  ilia  afford  lateral,  expansions,  which 
support  some  of  the  contents  of  the  abdo- 
men, and  the  pelvic  brim  completed  behind 
by  the  promontory  of  the  sacrum,  forms  the 
opening  by  which  the  cavity  of  the  true  pelvis 
communicates  with  that  of  the  abdomen. 


Between  the  inferior  margin  of  the  thorax 
and  the  superior  margin  of  the  false  pelvis  are 
stretched  muscular  lamellae  and  tendinous  ap- 
oneuroses,  the  cingulum  abdominis  musculoso- 
aponeuroticum  of  Albinus  and  Haller,  which, 
with  integument,  cellular  membrane,  &c.  form 
the  anterior,  lateral,  and  for  the  most  part 
the  posterior  walls  of  the  abdomen,  and  circum- 
scribe that  space  to  which  we  have  already 
alluded  under  the  name  of  the  cavity  of  the 
abdomen. 

The  superior  wall  of  the  abdomen  is  the 
diaphragm,  and  the  inferior  wall  of  the  abdo- 
men, strictly  so  called,  is  formed  by  the  ilia 
and  their  muscles,  and  is  open  in  the  centre  at 
the  superior  outlet  of  the  pelvis ;  but  if  the 
abdominal  and  pelvic  cavities  be  considered  as 
one,  then  those  parts  which  fill  up  the  inferior 
outlet  of  the  latter  must  be  considered  as 
likewise  constituting  the  inferior  wall  of  the 
former. 

In  the  male  adult  the  abdomen  presents  an 
expanded  convex  surface  anteriorly  (the  ante- 
rior wall  or  proper  abdominal  region) ;  poste- 
riorly a  broad  surface  not  so  extensive,  situated 
between  the  last  ribs  and  the  superior  margin 
of  the  pelvis,  and  divided  into  two  by  the 
lumbar  portion  of  the  spine  (the  posterior  wall, 
the  loins,  or  lumbar  regions.)  The  anterior 
and  posterior  walls  are  connected  with  each 
other  on  the  sides  by  two  narrow  regions  (the 
lateral  walls  or  the  flanks.) 

The  outline  of  the  anterior  wall    or    pro- 
per abdominal  region  constitutes  an  oval,  whose 
long  axis  is  vertical.     The  surface  is  generally 
more  or  less  convex  during  life,  proportionally 
with  the  degree  of  embonpoint  of  the  indivi- 
dual, and  also  according  to  the  condition  of  the 
diaphragm.    After  death,  excepting  in  very  fat 
subjects,  or  where  the  intestines  or  peritoneal 
cavity  are  much  distended  from  any  cause,  this 
surface  is  in  a  variable  degree  collapsed,  and 
more  or  less  concave,  but  especially  so  in  very 
thin  and  emaciated  subjects.     There  is  a  con- 
stant adaptation  in  the  condition  of  this  surface 
to  that  of  the  abdominal  viscera,  so  that  the 
practitioner  can  in  general  argue  pretty  accu- 
rately, from  the  state  of  the  abdominal  surface, 
respecting  that  of  the  abdominal  viscera,  ex- 
cept in  cases  where  every  thing  is  masked  by  a 
superabundant  deposition  of  adipose  substance. 
So  close  is  the  apposition  of  the  abdominal  wall 
to  the  surfaces  of  the  subjacent  viscera,  that  in 
some  cases  of  extreme  emaciation  the  peristaltic 
movement  of  the  intestinal  canal  is  manifested 
by  the  successive  elevation  and  depression  of 
small  portions  of  the  walls  corresponding  to  the 
dilated   and  contracted   portions  of  intestine. 
This   surface  is   divided  into  two  equal  and 
symmetrical  portions  by  a  groove  which  exists 
along  the  middle  line,  and  which  is  chiefly  ap- 
parent in  the  two  superior  thirds.     This  groove 
commences  below  the  ensiform  cartilage,  where 
there  is  a  slight  depression,  denominated  the 
scrobiculus  cordis,  (creux   de  1'estomac.)     In 
this  line,  about  midway  between  the  pubis  and 
xiphoid  cartilage,  is  the  round  depression  called 
the  umbilicus  or  navel.  Just  over  the  pubis  there 
is  a  prominent  surface  in  both  sexes  covered 


ABDOMEN. 


Eg-.  2. 


with  liair  ;  in  the  female  it  is  much  more  pro- 
minent than  in  the  male,  and  is  called  the  mom 
Veneris.  In  subjects  where  the  muscular  sys- 
tem is  well  developed,  there  exists  on  each  side 
of  this  median  groove  an  oblong  convexity,  ex- 
tending from  the  anterior  surface  of  the  lower 
part  of  the  chest  to  the  pubis ;  these  convexities 
indicate  the  situation  of  the  rectl  muscles.  In 
statues  representing  athletic  men,  the  promi- 
nences occasioned  by  these  muscles  are  gene- 
rally very  well  shewn,  and  are  divided  by  trans- 
verse superficial  depressions  into  smaller  qua- 
drilateral portions,  generally  three  in  number. 
External  to  these  prominences  there  is,  in 
similar  muscular  subjects,  a  fissure  extending 
from  the  border  of  the  chest,  in  a  slightly 
curved  course  with  external  convexity,  to  a  point 
a  little  to  the  inner  side  of  the  anterior  superior 
spine  of  the  ilium ;  this  fissure  has  internal  to 
it  the  prominence  from  the  recti  muscles,  and 
external  that  from  the  broad  muscles  of  the 


abdomen.     Gerdy  calls  it  the  lateral  groove  or 
furrow  of  the  abdomen.*     (See  Jig.  1.) 

The  posterior  wall  or  the  region  of  the  loins, 
(lumbar  region,)  is  in  every  way  of  less  extent 
than  the  anterior.  Its  vertical  height  is  equal 
to  the  distance  between  the  last  rib  and  the 
margin  of  the  ilium.  It  is  continuous  on  the 
sides  with  the  flanks,  and  is  divided  along  the 
middle  line  by  a  groove,  corresponding  to  the 
lumbar spinous  processes,  into  two  symmetrical 
portions,  each  of  which  forms  a  large  and  pro- 
minent relief.  Each  relief  corresponds  to  a 
great  muscular  mass,  which  almost  wholly  oc- 
cupies this  region,  and  its  prominence  is  greatest 
when  those  muscles  are  in  a  state  of  contrac- 
tion, as  during  the  erect  posture.  Each  relief 
is  concave  from  above  downwards,  and  in 
a  degree  directly  proportionate  to  the  conlrac- 

*  Gerdy,  Anatomic  des  Formes  Exterieures,  p.  189. 
The  above  engraving  is  reduced  from  the  folio  platt-s 
which  accompany  this  work. 


ABDOMEN. 


tion  of  the  muscles,  insomuch  that  in  some  in- 
dividuals the  concavity  is  habitually  very  con- 
siderable, as  in  those  who  carry  burdens  on  the 
head  or  in  front  of  the  body,  in  pregnant  wo- 
men, &c.  (See/g.  2.) 

The  limit  of  this  wall  on  each  side  is 
indicated  by  a  groove  or  fissure  which  passes 
.obliquely  upwards  and  outwards  towards  the 
ribs,  and  corresponds  to  the  outer  margin  of 
each  relief,  or  that  of  the  lumbar  muscles; 
these  lines  also  indicate  the  posterior  limits 
of  the  lateral  walls  of  the  abdomen,  or  the 
flanks.  Anteriorly  the  flank  of  each  side  is 
continuous  with  the  anterior  wall  of  the  abdo- 
men ;  above  it  is  limited  by  the  margin  of  the 
thorax,  and  below  by  the  margin  or  crest  of  the 
ilium.  It  is  concave  on  its  surface  from  above 
downwards,  (except  in  cases  of  great  embon- 
point, where  the  concavity  is  obliterated,)  and 
convex  from  before  backwards.  Gerdy  remarks 
that  in  subjects  in  which  the  muscles  have  a 
considerable  development,  a  relief  is  formed 
just  above  the  crista  ilii  by  the  broad  muscles 
of  the  abdomen  at  their  insertion  into  this 
osseous  border.  Upon  antique  statues  this 
relief  is  in  general  made  too  prominent. 

The  anterior  or  proper  abdominal  region  has 
been  subdivided  into  smaller  compartments, 
with  a  view  to  facilitating  descriptions,  patho- 
logical or  otherwise.  This  subdivision  is  com- 
pletely arbitrary,  and  therefore  some  differences 
will  be  found  among  the  various  anatomical 
authors  as  to  the  precise  limits  of  each  region. 
That  which  is  here  subjoined,  however,  appears 
to  be  pretty  generally  agreed  upon  in  this 
country.  Lines  connecting  particular  points 
drawn  upon  the  surface,  mark  out  these  subdi- 
visions, and  if  planes  be  supposed  to  be  carried 
from  these  lines  horizontally  backwards  to  the 
posterior  wall,  the  cavity  of  the  abdomen  will 
thus  be  divided  into  segments,  each  of  which 
has  its  particular  portion  of  the  abdominal 
viscera.  It  is  an  instructive  exercise  for  the 
student  to  practise  himself  in  examining  the 
particular  viscera  which  correspond  to  particu- 
lar regions.  We  are  thus  enabled,  as  Blandin 
has  remarked,*  to  resolve  the  problem,  "  a 
point  of  the  surface  of  the  abdomen  being 
wounded  deeply  in  a  given  direction,  to  de- 
termine what  organs  have  been  injured  ;  and 
reciprocally,  an  organ  having  been  wounded 
in  a  particular  part  of  the  abdominal  cavity 
by  a  sharp  instrument,  which  entered  in  a 
given  direction,  to  determine  what  part  of 
the  abdominal  walls  must  necessarily  have 
been  injured. "t 

The  limits  of  these  several  regions  or  com- 
partments may  be  thus  indicated  :  j  let  a  line 
be  drawn  horizontally  from  the  extremity  of  the 
last  rib  on  one  side  to  the  same  point  on  the 
other,  and  let  another  line  parallel  to  the  pre- 
ceding be  drawn  between  the  two  anterior 
superior  spinous  processes  of  the  ilium ;  the 

*  Anatomie  Topographique,  p.  423. 

t  The  division  of  the  surface  of  the  abdomen  into 
regions  is  as  old  as  Aristotle. 

t  See  an  engraving  exhibiting  these  subdivisions, 
in  the  article  ABDOMEN  of  the  CYCLOPEDIA  OF 

PRACTICAL  MEDICINE. 


abdominal  surface  is  thus  divided  into  three 
great  regions,  each  of  which  is  subdivided  into 
three  by  means  of  a  vertical  line  let  fall  on  each 
side  from  the  anterior  extremity  of  the  seventh 
or  eighth  rib  to  a  point  a  little  external  to  the 
spine  of  the  pubis.  Nine  regions  are  thus 
marked  out,  the  relations  and  boundaries  of 
which  may  be  described  as  follows. 

The  superior  region,  or  that  above  the  first 
horizontal  line,  is  the  Epigastrium,  which  name 
it  derives  from  its  close  relation  to  the  stomach  : 
(i7r>,  upon,  over ;  yew-rug,  the  stomach.)  The  epi- 
gastrium is  bounded  superiorly  and  laterally  by 
the  margin  of  the  thorax,  and  its  inferior  limit 
is  indicated  by  the  transverse  line.  The  verti- 
cal lines  subdivide  it  into  two  lateral  regions, 
each  of  which  is  bounded  immediately  above 
by  the  lower  margin  of  the  thorax,  beneath 
which  these  regions  extend  in  a  direction  up- 
wards and  backwards :  they  are  hence  called 
hypochondria  (Wo,  under,  p^ov^os,  cartilage). 
Between  the  hypochondria,  is  the  proper 
epigastric  region,  which  at  its  superior  part  and 
just  below  the  xiphoid  cartilage  presents  the 
depression  already  alluded  to  under  the  name  of 
scrobiculus  cordis  (scrobiculus,  the  diminutive 
of  scrobs,  a  depression). 

Immediately  below  the  epigastrium,  and 
separated  from  it  by  the  superior  horizontal 
line,  is  the  umbilical  region,  which  has  its 
name  from  the  presence  of  the  umbilicus  in  it. 
This  region  is  limited  above  and  below  by  the 
two  horizontal  lines,  and  is  subdivided  by  the 
intersection  of  the  two  vertical  lines  into  three 
regions  :  the  lateral  ones  are  the  lumbar  regions, 
so  called  from  their  correspondence  with  those 
portions  of  the  posterior  abdominal  wall  which 
bear  the  same  name  ;  and  the  middle  one  is  the 
proper  umbilical  region. 

Between  the  inferior  horizontal  line  and  the 
margin  of  the  pelvis,  is  the  hypogastrium,  (VTTO, 
beneath,  yacrT*!^,  the  stomach).  This  region  is  li- 
mited below  in  the  centre  by  the  pubis,  and  on 
each  side  it  communicates  with  the  upper  part 
of  the  thigh.  It  is  subdivided  into  the  iliac 
regions  on  each  side,  and  the  proper  hypo- 
gastric  or  pubic  region  in  the  centre.  The  two 
former  constitute  the  upper  or  abdominal 
portion  of  the  great  region  of  the  groin,  which 
is  completed  inferiorly  by  the  upper  part  of  the 
anterior  surface  of  the  thigh.  These  regions 
afford  peculiar  interest  to  the  surgical  ana- 
tomist, in  consequence  of  the  occurrence  in 
them  ofkthe  most  common  forms  of  hernia.* 
(See  GROIN,  REGION  OF  THE.) 

The  structures  which  enter  into  the  com- 
position of  the  abdominal  parietes,  or  their 
elements,  (as  the  term  has  been  lately  applied,) 
are — 1.  the  skin:  2.  the  subcutaneous  tissue 
or  superficial  fascia :  3.  muscles  and  their 
aponeurotic  expansions  :  4.  a  particular  fibrous 
expansion,  or  fascia  :  5.  a  thin  and  filamea- 
tous  cellular  tissue,  which  separates  the  fascia 
just  named  from  the  sixth  element:  6.  the  peri- 
toneum, which,  however,  is  not  to  be  found  in  the 
composition  of  all  the  walls  of  the  abdomen. 

*  Velpeau  applies  the  term  xone  to  the  primary 
regions  included  between  the  horizontal  lines. — 
Anat.  Chirurg.  t.  ii. 


ABDOMEN. 


*3 


In  and  between  these  several  structures  ramify 
the  various  arteries,  veins,  lymphatics,  and 
nerves,  which  constitute  the  vascular  and  ner- 
vous supply  to  the  abdominal  parietes. 

1.  The  skin  on  the  anterior  and  lateral  parts 
of  the  abdomen  is  thin  and  smooth,  and  in 
some  parts  covered  with  hairs,  as  along  the 
middle  line,  especially  below  the  umbilicus  and 
over  the  pubic  region.  Along  the  median  line 
the  cutaneous  follicles  are  largely  developed, 
and  during  pregnancy  an  increased  secretion  of 
pigmentum  is  said  to  take  place,  producing 
a  brownish  colour  of  the  skin  in  these  regions. 
In  women  who  have  borne  children,  the 
skin  becomes  wrinkled  to  a  considerable  de- 
gree, and  the  epidermis  exhibits,  as  Winslow 
has  remarked,  a  great  number  of  lozenge- 
shaped  spaces  disposed  in  a  reticular  manner.* 

In  the  epigastric  region  the  skin  is  much 
more  sensitive  during  life  than  in  the  other 
parts  of  the  abdomen,  and  with  some  persons 
sympathizes  with  the  stomach  in  a  remarkable 
degree,  so  that  pressure  on  it  even  in  the 
healthy  state  produces  a  degree  of  pain  or  un- 
easiness in  that  organ,  or  even  a  tendency  to 
nausea.  In  the  umbilical  region  we  observe  a 
depression,  the  floor  of  which  is  more  or  less 
elevated  in  the  centre.  This  depression  is  de- 
nominated the  navel  or  umbilicus,  (the  dimi- 
nutive of  umbOj  a  nob  or  button.)  It  is 
produced  by  the  firm  adhesion  of  the  skin  to 
the  subjacent  structures,  its  true  nature  being 
that  of  a  cicatrix,  occupying  the  site  of  a 
former  perforation  through  which  the  umbilical 
arteries  and  veins  and  the  urachus  passed  in 
maintaining  the  circulation  between  the  foetus 
and  placenta.  In  very  fat  persons,  the  depth 
of  the  depression  is  often  very  much  increased 
by  reason  of  the  great  thickness  of  the  abdomi- 
nal parietes,  and  in  some  instances  its  form 
assumes  that  of  a  slit,  and  sometimes,  instead 
of  a  depression,  there  is  a  greater  or  Jess  pro- 
minence of  the  integument. 

In  the  lumbar  region  the  skin  is  thicker  and 
firmer  than  in  the  others;  and  we  generally 
find  it  in  a  state  of  congestion  after  death,  in 
consequence  of  the  position  of  the  body. 

2.  The  subcutaneous  cellular  tissue  on  the 
anterior  surface  of  the  abdomen  has  obtained 
especial  attention  from  anatomists,  particularly 
that  portion  of  it  which  is  found  in  the  hypo- 
gastric  regions.  It  is  denominated  the  superficial 
fascia,^  and  is  merely  an  expanse  of  cellular 
tissue  possessing  the  same  general  characters 

*  Winslow's  Anatomy,  by  Douglas,  v.  ii.  p.  160. 

t  The  application  of  the  term  fascia  to  the  sub- 
cutaneous cellular  investment  in  various  parts  of  the 
body  has  occasioned  no  small  degree  of  confusion 
among  anatomists.  A  singular  degree  of  confusion 
exists  in  Velpeau's  description  of  this  fascia  :  he 
observes  in  one  place  that  the  deep  layers  of  the 
subcutaneous  cellular  tissue  constitute  the  super- 
ficial fascia,  and  in  the  next  page  states  that  "  the 
superficial  fascia  is  nothing  else  than  the  cellular 
tissue  condensed,  whose  laminae  strongly  applied 
one  against  the  other,  are  ultimately  reduced  to 
somewhat  of  the  aponeurotic  form."  I  shall  adhere 
to  this  latter  definition,  and  consider  superficial 
fascia  as  synonymous  with  subcutaneous  cellular 
tissue. — Velpeau  Anat.  Chirurg.  vol.  ii.  p.  4  and  5. 


as  that  which  is  found  in  all  other  parts  of  the 
body  ;  it  is  continued  upwards  over  the  thorax, 
laterally  into  the  region  of  the  back,  inferiorly 
along  the  thighs,  and  into  the  scrotum.  It  varies 
in  thickness  according  to  the  quantity  of  fat 
which  is  deposited  in  its  cells  ;"*  in  some  in- 
stances it  has  been  known  to  possess  a  thick- 
ness of  three  inches.  Thin  but  muscular  subjects 
afford  the  best  examples  from  which  to  study 
the  superfical  fascia  of  the  abdomen  :  in  such 
subjects  we  find  it  in  general  of  a  much  denser 
character  than  in  others,  very  strong  and  elastic 
and  easily  divisible  into  laminae,  produced, 
no  doubt,  by  the  pressure  which  it  experiences 
from  the  weight  of  the  abdominal  viscera,  and 
the  constant  attrition  occasioned  by  the  action 
of  the  abdominal  muscles.  In  the  iliac  region, 
immediately  above  Poupart's  ligament,  the 
density  of  this  fascia  is  most  conspicuous. 
Here  some  have  regarded  it  as  a  nbro-cellular 
membrane  ;  but  the  opaque  bands  which  give 
it  a  fibrous  appearance  are  merely  the  walls  of 
the  membranous  cells  rendered  thicker  and 
denser  than  they  are  in  other  parts.  I  cannot 
agree  with  Beclardf  that  it  presents  almost  all 
the  characters  of  an  aponeurosis,  inasmuch  as 
it  differs  from  an  aponeurosis  in  wanting  the 
shining  and  regular  surface,  and  in  possessing 
a  degree  of  elasticity  which  never  belongs  to 
aponeurotic  expansions.  The  elasticity  of  the 
superficial  fascia  is  remarkable,  and  is  by  some 
compared  to  the  elastic  expansion  over  the 
abdomen  of  the  larger  quadrupeds  ;  J  the 
comparison,  however,  is  inaccurate,  inasmuch 
as  they  are  two  distinct  tissues,  the  former 
being  cellular,  and  the  latter  the  aponeurosis 
of  the  oblique  muscles,  which  in  some  degree 
parta.kes  of  the  properties  of  the  yellow  elastic 
fibrous  tissue  (tissu  jaune). 

Inferiorly  the  superficial  fascia  moves  freely 
over  Poupart's  ligament,  and  is  continued  over 
the  thigh  (see  GROIN,  REGION  OF  THE).  Along 
the  middle  line  it  is  very  adherent  to  the  sub- 
jacent aponeurotic  structure  (the  linea  alba) 
as  well  as  to  the  skin, — a  fact  which  may  be 
remarked  of  the  subcutaneous  cellular  tissue  in 
other  parts  of  the  body,  and  which  was  long  ago 
noticed  by  Bordeu,  when  he  observed  that  the 
cellular  tissue  is  constricted  (etranglee)  in  all  its 
median  portion,  and  that  its  cells  (ballons  ou 
pouches)  are  closed  over  the  axis  of  the  body. 
When  this  superficial  fascia  is  dissected  off,  a 
very  thin  layer  of  cellular  membrane,  perfectly 
diaphanous,  is  found  to  adhere  to  the  subjacent 
aponeurotic  expansion.  This  will  be  found 
particularly  adherent  over  Poupart's  ligament, 
and  is  that  which  is  referred  to  by  some  ana- 
tomists (as  Manec,  Cloquet,  &c.,)  as  a  deep 
process  of  the  superficial  fascia  which  adheres 
to  Poupart's  ligament,  and  so  forms  a  super- 
ficial septum  between  the  abdomen  and  thigh. 
To  see  this  layer  the  superficial  lamina  should 
be  raised  by  commencing  the  dissection  of  it 

*  Cloquet  says  it  is,  as  it  were,  decomposed  by 
the  deposition  of  fat. — Recherches  Anat.  sur  les 
Hernies  de  1'Abdomen,  p.  11. 

t  Diet,  de  Medecine,  art.  abdomen. 

j    Vid.  Blandin,  Anat.  Topog. 

B  2 


ABDOMEN. 


below  and  carrying  it  upwards ;  the  expansion 
will  then  appear  to  arise  from  Poupart's  liga- 
ment, and  spread  over  the  subjacent  aponeuro- 
sis.  In  some  subjects  it  is  so  thin  as  to  appear 
to  be  little  more  than  the  proper  cellular  cover- 
ing of  the  muscle  and  its  aponeurosis,  but 
in  others  it  assumes  a  considerable  degree  of 
density.  It  may  be  called  the  deep  layer  of 
the  superficial  fascia;  it  deserves  attention  from 
the  fact  that  the  femoral  hernia,  in  its  ascent  on 
the  abdomen,  lies  between  it  and  the  super- 
ficial layer.  It  is  to  this  fascia  that  Scarpa 
must  allude  under  the  name  of  "  aponeurotic 
web  of  the  muscle  of  the  fascia  lata,"  and 
hence  some  have  called  it  Scarpa's  fascia.* 
The  whole  of  the  superficial  fascia  has  been 
called  Camper's  fascia,  because  it  was  first 
fully  described  by  that  writer.f 

On  the  posterior  wall  of  the  abdomen,  in  the 
lumbar  regions,  the  cellular  tissue  is  more 
abundant  and  more  lax;  here  we  frequently 
find  it  infiltrated  with  serous  fluid,  in  conse- 
quence of  the  usual  supine  posture  of  the  body 
after  death.  It  is  continuous  above  with  the 
subcutaneous  tissue  in  the  dorsal  region,  and 
below  with  that  in  the  gluUeal  regions.  It, 
too,  is  firmly  adherent  along  the  middle  line  to 
the  lumbar  spine  anteriorly,  and  to  the  skin 
posteriorly. 

3.  Muscles  and  aponeuroses. — The  abdo- 
minal parietes  owe  their  thickness  chiefly  to 
the  muscular  lamellae  and  the  aponeurotic  ex- 
pansions, which  enter  into  their  composition. 
In  the  anterior  and  lateral  walls  we  find  on 
each  side  five  pairs  of  muscles,  of  which  four 
are  constantly  present.  These  are,  1,  M.  obli- 
quus  externus ;  2,  obliquus  interims ;  3,  trans- 
versalis ;  4,  rectus  abdominis  ;  5,  pyramidalis, 
which  last  is  frequently  absent. 

1.  Obliquus  externus.  (Obliquus  descen- 
dens  ;  c&sto-abdominal  ;  ilio-pubi-costo-abdo- 
minal.) 

When  the  superficial  fascia  covering  the  an- 
terior and  lateral  surfaces  of  the  abdomen  has 
been  dissected  away,  this  muscle  is  brought  into 
view.  It  consists  of  a  flat  muscular  portion, 
situated  superiorly  and  posteriorly,  and  of  a 
tendinous  or  aponeurotic  lamella  anteriorly  and 
inferiorly,  but  which  is  largest  and  strongest  in 
the  latter  situation. 

The  muscular  portion  of  the  external  oblique 
is  attached  by  separate  fasciculi  to  the  external 
surfaces  of  the  eight  inferior  ribs,  from  the 
fifth  to  the  twelfth  inclusive.  These  fasciculi 
indigitate  at  their  attachment  with  similar 
ones,  of  the  serratus  magnus,  from  the  fifth 
to  the  ninth  inclusive,  and  of  the  latissimus 
dorsi  from  the  tenth  to  the  twelfth.  -From 
these  points  of  attachment,  described  by  most 
English  anatomists  as  the  origin  of  the 
muscle,  the  fibres  pass  obliquely  downwards 
and  forwards,  with  different  degrees  of  ob- 
liquity, the  middle  fibres  being  the  most  ob- 

*  Vid.  Scarpa  on  Hernia,    by  Wishart,    p.   22  ; 
also  Todd  on  Hernia,  Dub.  Hosp.  Reports,  vol.  i. 

S246  ;  and  Flood's  plates  of  Inguinal  and  Femoral 
ernia. 
|  Camper,  Icones  Herniarum,  p.  11. 


lique,  the  superior  taking  a  direction  nearly 
horizontally  inwards,  and  the  posterior  ones 
passing  nearly  vertically  downwards.  The  an- 
terior and  middle  fibres  are  inserted  into  the 
outer  convex  border  of  the  aponeurotic  lamella 
of  the  muscle,  but  the  posterior  are  inserted  into 
the  outer  lip  of  the  two  anterior  thirds  of  the 
crista  of  the  ilium  by  short  tendinous  fibres. 
The  fibres  of  this  muscle  vary  considerably  in 
length,  those  which  are  highest  up  being  the 
shortest,  the  middle  ones  the  longest,  and  next 
in  length  the  posterior  fibres.  The  aponeurotic 
lamella  of  the  external  oblique  muscle  is  found 
on  the  anterior  part  of  the  abdomen,  both  su- 
periorly and  inferiorly.  In  the  former  situa- 
tion the  aponeurosis  is  extremely  thin  and 
weak  ;  it  is  transparent,  so  that  the  upper 
extremity  of  the  rectus  muscle  which  it  covers 
is  visible  through  it.  This,  too,  is  the  narrow- 
est portion  of  the  aponeurosis,  which  increases 
in  breadth,  strength,  and  thickness  as  it  de- 
scends. The  aponeurosis,  like  the  muscular 
portion,  consists  of  a  series  of  fibres,  for  the 
most  part  inclined  obliquely  downwards  and 
inwards,  excepting  the  superior  ones,  whose 
direction  is  horizontal.  At  several  places  these 
fibres  are  separated  from  each  other  so  as  to 
allow  the  subjacent  muscle  to  be  seen  through 
the  interval.  At  various  parts  the  tendon  is 
perforated  by  vascular  apertures,  which  are  oc- 
casionally so  enlarged  as  to  admit  little  peri- 
toneal prolongations  to  pass  through  them. 
Along  the  middle  line,  from  the  ensiform  car- 
tilage to  the  symphysis  pubis,  the  aponeurosis 
forms  an  interlacement  with  its  fellow  of  the 
opposite  side,  and  this  interlacement  with  that 
of  the  subjacent  aponeuroses  constitutes  the 
tendinous  line  called  linea  alba,  which,  as 
Velpeau  observes,  may  be  regarded  as  the 
centre  in  which  all  the  fibrous  elements  of  the 
abdomen  terminate.  Just  above  the  symphysis 
pubis,  the  decussating  fibres  are  not  inter- 
mixed in  the  same  manner  as  in  other  parts  of 
the  linea  alba  :  there  the  bundle  of  one  side 
crosses  anteriorly  or  posteriorly  to  that  of  the 
other,  without  any  union  of  fibres,  to  be  in- 
serted into  the  pubis  of  the  side  opposite  to 
that  from  which  it  came. 

A  little  above  and  external  to  the  pubis,  a 
separation  of  the  fibres  of  the  tendon  of  the 
obliquus  externus  takes  place,  leaving  an 
opening  which  is  denominated  the  external 
abdominal  ring,  through  which  the  rounded 
bundle  composed  of  the  spermatic  vessels  and 
duct  (the  spermatic  cord)  passes  in  the  male, 
and  the  round  ligament  of  the  uterus  in  the 
female.  The  aponeurotic  fibres  which  form 
the  immediate  boundaries  of  this  opening  are 
termed  the  pillars  of  the  ring,  of  which  one  is 
superior,  internal,  and  anterior,  the  other  is  in- 
ferior, external,  and  posterior,  and  passes  behind 
the  cord.  External  and  inferior  to  this  opening, 
we  observe  that  the  aponeurosis  of  the  external 
oblique  muscle  is  extended  from  the  pubis  to 
the  anterior  superior  spine  of  the  ilium.  On 
the  pubic  side,  the  fibres,  which  are  the  same 
that  form  the  inferior  pillar  of  the  ring,  are  in- 
serted into  the  spine  of  the  pubis,  and  being 


ABDOMEN. 


reflected  backwards,  outwards,  and  a  little 
upwards,  they  are  likewise  inserted  into  the 
linea  ilio-pectinea,  which  commences  at  the 
spine  of  the  pubis.  The  lower  margin  of  the 
tendon  is  thus  folded  back  a  little  as  it  arches 
over  the  excavation  between  the  pubis  and 
ilium,  so  as  to  present  towards  the  abdomen  a 
slight  channel-like  excavation,  which  affords 
origin  to  the  muscular  fibres  of  the  internal 
oblique  as  well  as  to  those  of  the  transver- 
salis,  whilst  it  has  the  appearance  of  a  rounded 
ligamentous  cord  towards  the  thigh.  In  this 
manner  is  formed  Poupart's  ligament,  which, 
contrary  to  what  its  usual  name  denotes,  is 
not  a  distinct  ligamentous  cord,  but  the  in- 
ferior margin  of  the  external  oblique  stretched 
from  pubis  to  ilium,  and  folded  a  little  upon 
itself.  By  its  superior  margin  it  is  continuous 
with  the  fibres  of  the  tendon  of  the  external 
oblique,  which  fall  obliquely  upon  it ;  by  its  in- 
ferior margin  it  is  intimately  connected  with  the 
fascia  lata  of  the  thigh  ;  externally  it  is  inserted 
into  the  anterior  superior  spine  of  the  ilium ;  and 
by  its  pubic  extremity  it  has  three  attachments, 
1.  to  the  body  of  the  pubis;  2.  to  the  spine 
of  the  same;  and  3.  to  the  linea  ilio-pectinea, 
constituting  what  has  been  called  GimbernaCs 
ligament,  which  has  a  sharp  slightly  crescentic 
margin  directed  backwards  and  outwards  to- 
wards the  femoral  vessels.*  (See  GROIN, 
REGION  OF  THE.) 

The  external  abdominal  ring  is  a  triangular 
opening,  situated  obliquely  ;  the  superior  angle 
being  directed  upwards  and  outwards,  and  its 
base,  represented  by  a  line  uniting  the  pubic 
insertions  of  the  two  pillars,  resting  upon  the 
pubis.  The  superior  angle  is  formed  evidently 
by  the  separation  of  the  fibres  of  the  aponeu- 
rosis,  the  primitive  direction  of  which  is  the  same 
as  that  of  a  perpendicular  from  the  apex  to  the 
base  of  the  triangle,  viz.  downwards  and  in- 
wards, (sacrad  and  pubad.)  This  separation, 
however,  is  strengthened,  and  the  angle  round- 
ed by  some  tendinous  fibres  which  inter- 
sect the  oblique  ones  nearly  at  a  right  angle, 
arising  as  a  cord  of  variable  thickness  from 
Poupart's  ligament,  and  passing  upwards  and 
inwards  over  the  apex  of  the  ring,  gradually 
separating  into  several  tendinous  fibres.  These 
fibres  are  sometimes  very  strong,  at  other 
times  very  feeble  and  scarcely  perceptible ; 
but  it  rarely,  if  ever,  happens  that  they  are 
completely  absent ;  they  have  been  termed 
intercolumnal  bands.  I  have  seen  them  so 
strong  that  they  could  be  distinctly  dissected 
off  the  external  oblique  aponeurosis,  like  a 
separate  tendinous  expansion;  but  most  fre- 
quently they  are  so  united  to  the  aponeurosis 
as  to  render  it  impossible  to  remove  them 
without  injury  to  it.  These  fibres  are  evi- 
dently intended,  as  Scarpa  expresses  it,  "  to 
fix  the  limits  of  the  inguinal  ring,  and  to 
oppose  the  further  divergence  of  the  tendi- 
nous pillars  towards  the  side."  They  are 

*  The  terms  crural  arch,  and  ligament  of  Fallopius, 
are  also  used  synonymously  with  Poupart's  liga- 
ment. Velpeau  calls  it  bandelette  ilio-pubieune  du 
grand  oblique. 


equally  met  with,  although  not  nearly  so  much 
developed,  in  women  and  children  as  in  men  ; 
and  Mr.  Lawrence  asserts  that  in  old  herniae 
they  are  particularly  strong.  I  cannot  confirm 
this  remark  from  my  own  observation,  as  in 
my  dissections  of  old  herniae,  I  have  not 
found  them  particularly  developed;  nor  is  it  con- 
sistent with  the  general  result  of  pressure  from 
within  on  tendinous  fibres  to  believe  that  such 
pressure  would  produce  an  increase  of  deve- 
lopment in  them. 

The  size  of  the  external  abdominal  ring  is 
greatest  in  the  male  subject,  but  here  it  varies 
considerably,  sometimes  closely  embracing 
the  cord  as  it  passes  through  it,  and  at  others 
appearing  much  too  large  for  it.  In  the  male 
the  parts  which  pass  through  it  are  the  sper- 
matic cord,  enveloped  in  its  proper  tunic,  and 
in  one  of  condensed  cellular  membrane  pro- 
longed from  the  fascia  transversalis,  a  branch 
of  the  genito-crural  nerve,  the  cremaster  mus- 
cle, the  cremasteric  artery,  and  the  spermaticus 
superficialis  nerve.  In  the  female,  we  find 
the  round  ligament  of  the  uterus,  covered  and 
accompanied  by  similar  parts,  excepting  (he 
cremaster.  From  the  margin  of  the  external 
abdominal  ring,  a  cellular  expansion  or  fascia 
is  carried  over  the  cord  or  round  ligament, 
and  has  been  denominated  fascia  spermatica. 
This  fascia  consequently  forms  a  covering  of 
any  hernia  that  may  be  protruded  through  the 
external  ring;  and,  accordingly,  in  old  herniae 
we  find  it  greatly  thickened.  Its  formation 
is  simply  in  accordance  with  what  we  find  oc- 
curring in  all  parts  of  the  body,  viz.  that  when 
any  part  passes  through  an  opening  in  a  fibrous 
membrane,  it  carries  with  it  a  cellular  expan- 
sion from  the  margin  of  that  opening.  This 
we  observe  in  the  passage  of  the  vena  cava 
through  the  diaphragm,  of  the  urethra  through 
the  triangular  ligament  or  deep  perineal  fascia. 
This  view  confirms  the  opinion  of  Sir  A. 
Cooper,  that  this  fascia  is  a  production  from 
the  margin  of  the  ring  itself. 

The  external  oblique  muscle  is  covered  in 
all  its  extent  by  the  superficial  fascia ;  its  costal 
margin  is  related  to  the  serratus  magnus,and  to 
the  latissimus  dorsi,  with  which  muscle  it  is  also 
in  close  relation  by  its  posterior  margin,  being 
sometimes  slightly  overlapped  by  the  anterior 
margin  of  the  latissimus,  but  at  others  separated 
from  that  muscle  by  a  triangular  interval 
through  which  the  fibres  of  the  obliquus  inter- 
nus  appear:  interiorly  the  fascia  lata  of  the 
thigh  is  related  to  the  margin  of  the  external 
oblique  muscle,  both  as  it  covers  the  glutaei,and 
as  it  lies  in  front  of  the  thigh.  Along  the 
middle  line  the  aponeuroses  of  opposite  sides 
meet  at  the  linea  alba,  and  superiorly  the  mus- 
cular fibres  are  related  to  and  sometimes  con- 
nected by  a  fleshy  slip  with  those  of  the  pecto- 
ralis  major,  and  the  aponeurosis  is  continuous 
with  that  of  the  same  muscle.*  When  the  ex- 

*  "  By  its  position,  the  direction  of  its  fibres,  and 
the  short  distance  to  which  its  fleshy  portion  extends 
forwards,  the  external  oblique  corresponds  so  much 
to  the  external  intercostals,  that  one  is  led  to  say 
that  it  represents  them  in  the  abdomen," — Mechel. 


ABDOMEN. 


ternal  oblique  is  removed  from  its  osseous  at- 
tachments, and  raised  inwards,  it  is  found  to 
cover  the  internal  oblique,  with  part  of  the  ten- 
don of  which  it  is  ultimately  united  as  the  two 
tendons  approach  the  linea  alba. 

2.  Obliquus  internus  (obliquus  ascendens, 
ilio-abdominal,  ilio-lumbo-costi-abdominal)  is 
smaller  than  the  preceding  muscle,  which  it 
resembles  in  shape  and  general  characters.  The 
direction  of  its  fibres,  however,  is  opposite, 
inasmuch  as  the  fibres  of  the  two  muscles 
decussate  with  each  other,  thus  adding  con- 
siderably to  the  strength  of  the  abdominal  wall, 
and  forming  a  great  protection  against  visceral 
protrusions.  The  external  attachments  (or,  as 
systematic  writers  call  it,  the  origin  of  the  mus- 
cle) is  1.  by  short  fleshy  fibres  to  the  tendinous 
expansion  covering  the  lumbar  mass  of  muscles, 
called  fascia  lumborum,  which  is  formed  by 
the  posterior  lamina  of  the  tendon  of  the  trans- 
versalis  abdominis :  2.  to  the  two  anterior 
thirds  of  the  middle  portion  of  the  crista  ilii, 
between  the  external  oblique  and  the  transver- 
salis  as  far  forwards  as  the  anterior  superior 
spine  :  3.  to  the  groove  in  the  upper  or  abdo- 
minal surface  of  Poupart's  ligament  for  about 
its  external  third.  The  superior  fibres  pass 
upwards  and  inwards,  and  are  inserted  by 
fleshy  slips  into  the  cartilages  of  the  twelfth,  ele- 
venth, and  tenth  ribs,  in  the  intervals  between 
which  they  are  either  separated  from  the  inter- 
costal muscles  by  a  fibrous  intersection,  or  con- 
founded with  them,  and  by  a  tendinous  aponeu- 
rosis  into  the  cartilages  of  the  ninth,  eighth,  and 
seventh  ribs  as  well  as  into  the  xiphoid  cartilage. 
Lower  down,  the  fibres  which  arise  from  the 
crista  ilii,  as  well  as  those  from  Poupart's  liga- 
ment, pass  inwards,  the  superior  obliquely 
upwards  and  inwards,  the  inferior  more  hori- 
zontally, and  the  lowest  fibres  inclining  a  little 
downwards,  and  are  all  inserted,  like  those  of 
the  obliquus  externus  into  the  outer  convex 
margin  of  an  aponeurotic  expansion,,  which  goes 
to  be  inserted  along  the  middle  line.  This  ten- 
don passes  inwards  for  a  short  distance,  nearly 
as  far  as  the  outer  margin  of  the  rectus  muscle, 
as  a  single  lamina.  Along  this  margin,  and  as 
low  down  as  the  inferior  fourth  of  the  rectus 
muscle,  the  tendon  divides  into  two  laminae, 
of  which  the  anterior  adheres  to  the  posterior 
surface  of  the  tendon  of  the  external  oblique, 
and  the  posterior  to  the  subjacent  tendon  of  the 
transversalis,  both  laminae  going  to  be  inserted 
into  the  ensiform  cartilage  and  linea  alba,  the 
one  in  front,  the  other  behind,  the  rectus  muscle. 
(Seej%.  4,  a. )  For  a  distance,  however,  corres- 
ponding to  the  inferior  fourth  of  the  rectus 
muscle,  the  tendon  of  the  obliquus  internus  re- 
mains undivided,  and  does  not  adhere  to  that  of 
the  obliquus  externus.  It,  however,  is  united, 
although  not  inseparably,  to  the  tendon  of  the 
transversalis,  and  both  go  in  front  of  the  rectus 
to  be  inserted  into  the  linea  alba  and  pubis : 
these  tendons  are  here  called  by  some  the  con- 
joined tendons.  Along  the  line  at  which  the 
tendon  of  the  obliquus  internus  divides  into  two 
laminae.,  the  aponeurosis  of  the  obliquus  externus 


and  that  of  the  trausversalis  adhere  to  it  more 
closely  than  they  do  externally  to  that  line,  and 
thus  a  thickened  portion  of  the  abdominal 
aponeurosis  is  formed,  taking  the  course  of  the 
outer  margin  of  the  rectus  muscle :  this  line  is 
called  the  Linea  semilunaris,  and  is  that  in  which 
the  operation  of  paracentesis  abdominis  used 
formerly  to  be  practised. 

The  inferior  margin  of  the  obliquus  internus 
is  deserving  of  particular  attention.  The  in- 
ferior fibres  attached  to  the  external  third  of 
Poupart's  ligament  in  the  groove  formed  in  it 
pass  transversely  inwards  and  parallel  to  the 
ligament,  crossing  over  the  spermatic  cord,  to 
be  inserted  into  the  pubis.  Here  the  muscle  is 
confounded  with  the  inferior  fibres  of  the  sub- 
jacent one,  the  transversalis ;  so  that  it  is  not 
only  difficult  to  say  which  muscle  passes  low- 
est down,  but  it  is  difficult,  and  often  impossible, 
to  separate  the  two  muscles.  Hence  the  lower 
margins  of  the  fleshy  fibres  as  well  as  of  the  apo- 
neuroses  of  these  two  muscles  are  constantly 
spoken  of  conjointly ;  however,  I  have  several 
times  succeeded  in  separating  them  distinctly, 
and  I  am  decidedly  of  opinion  that  the  apo- 
neurosis of  the  obliquus  internus  seldom  or 
never  descends  so  low  down  as  that  of  the  trans- 
versalis. The  lowest  of  the  fibres  of  the  obliquus 
internus  are  sometimes  observed  to  separate  a 
little  from  the  others,  so  as,  instead  of  a  directly 
transverse,  to  assume  a  course  slightly  curved 
with  the  concavity  upwards  and  a  little  outwards, 
lying  in  front  of  the  cord ;  in  some  cases  fibres 
of  this  kind  are  observed  to  lie  in  front  of  th^ 
spermatic  cord,  and  to  descend  much  lower 
down,  taking  of  course  a  much  more  curved 
direction,  still  attached  on  the  outside  to  Pou- 
part's ligament,  and  on  the  inside  to  the  pubis, 
so  that  a  series  of  curved  fibres  are  thus  found 
to  adhere  to  the  anterior  surface  of  the  cord  and 
of  the  tunica  vaginalis,  exhibiting  an  equal  num- 
ber of  reversed  arches.  But  this  disposition  is 
rarely  seen  in  its  most  highly  developed  state, 
excepting  where  some  tumour  has  been  con- 
nected with  the  cord  or  testicle,  as  hernia, 
hydrocele,  &c. 

This  arched  arrangement  of  muscular  fibres 
in  connection  with  the  spermatic  cord  and 
tunica  vaginalis  testis  constitutes  the  Cremas- 
ter  muscle  (K^^atu,  suspendo,}  the  great  tenuity 
of  which  in  the  natural  state  of  the  parts  has  ren- 
dered it  difficult  to  determine  its  precise  attach- 
ments, and  consequently  has  given  rise  to  the 
great  discrepancy  which  is  observable  between 
the  descriptions  of  different  writers.  When 
this  muscle  is  examined  in  a  case  of  old  hernia 
or  hydrocele,  it  is  found,  as  Scarpa  originally 
described  it,  to  consist  of  two  bundles  ;  the  first, 
external  to  the  cord  which  arises  from  Poupart's 
ligament  along  with  the  internal  oblique,  follows 
the  course  of  the  spermatic  cord,  which  it  ac- 
companies through  the  external  abdominal  ring, 
sending  at  intervals  fibres  arching  in  front  of 
the  cord  to  join  a  similar  bundle  on  the  inner 
side,  as  may  be  seen  in  the  accompanying  en- 
graving from  a  plate  in  Sir  A.  Cooper's  work 
on  the  testis  (fig.  3 ).  Inferiorly,  this  bundle,  a 


ABDOMEN. 


Fig.  3. 


c,  the  internal  oblique  ;  e,  the  descending  fibres ;  /, 
point,  of  insertion  into  the  pubis  ;  h,  one  of  the  re- 
versed arches ;  d,  conjoined  tendons  ;  a,  rectus 
muscle. 

good  deal  diminished  in  size,  crosses  over  the 
inferior  and  anterior  portion  of  the  tunica  vagi- 
nalis  testis,  and  begins  to  ascend  along  the  inner 
side  of  the  testicle  and  cord,  keeping  more  pos- 
teriorly :  this  constitutes  the  second  bundle ;  it 
gradually  increases  in  size  as  it  ascends  by  re- 
ceiving the  transverse  fibres  from  the  bundle  of 
the  opposite  side,  and  it  is  inserted,  sometimes 
by  a  distinct  tendon,  into  the  pubis  near  its  spine. 
In  some  cases  I  have  totally  failed,  even  after 
the  most  careful  dissection,  in  detecting  a  conti- 
nuity by  muscular  fibre  between  these  two  bun- 
dles, insomuch  as  to  lead  me  to  imagine  that 
they  may  be  connected  by  a  very  condensed  cel- 
lular tissue  or  thin  aponeuro^c  lamella  after  the 
manner  of  the  digastric  musaj^s.  .  In  general  the 
external  bundle  is  largej^han  the  internal,  but 
Cloquethas  seen  the  re^K  three  times ;  and  on 
referring  to  my  notes,  I  mjd  I  have  seen  two 
instances  in  which  the  internal  bundle  exceeded 
the  external  in  size.  V 

Many  anatomists  have  notic^ed  only  the  ex- 
ternal bundle  of  the  cremaster?  and  altogether 
overlooked  its  reversed  arches,  which  is  not  to 
be  wondered  at  when  we  remember  that  even 
where  the  lateral  bundles  are  strong  and  well 
developed,  the  arched  fibres  are  sometimes  pale 
and  thin.  However,  the  description  now 
given  is  pretty  generally  admitted  as  the  true 
one,  and  is  sanctioned  by  such  observers  as 
Scarpa,  Cloquet,  Cooper,  Velpeau,  and  I  may 
add  that  I  have  seen  this  arrangement  in  cases 
where  both  testicle  and  cord  were  healthy.  It 
would  appear  that  its  formation  is  effected  by 
the  testicle  in  its  descent,  for  before  that  takes 
place  the  muscle  does  not  exist ;  at  least  such  is 
the  result  of  Cloquet's  observations  on  a  con- 
siderable number  of  foetuses  before,  during,  and 
after  the  descent  of  this  organ.  Before  the  de- 
scent the  gubernaculum  testis  occupies  the 
inguinal  canal,  and  is  covered  by  the  fibres  of 
the  internal  oblique,  which  adhere  to  it :  when 


the  gubernaculum  is  drawn  down,  these  fibres 
descend  with  it,  forming  a  series  of  reversed 
arches. 

In  some  female  subjects  we  see  an  arrange- 
ment of  the  inferior  fibres  of  the  internal  oblique 
as  they  cross  over  the  round  ligament,  which 
resemble  a  rudimentary  state  of  the  cremaster 
muscle. 

A  thin  layer  of  cellular  tissue,  sometimes 
containing  a  small  quantity  of  fat,  is  interposed 
between  the  anterior  surface  of  the  obliquus 
internus  and  the  obliquus  externus.  At  the  infe- 
rior edge  of  the  obliquus  internus  the  spermatic 
cord  is  seen  emerging  from  the  abdomen  and 
passing  obliquely  inwards  and  a  little  down- 
wards to  the  external  abdominal  ring.  Here  it  lies 
in  a  groove  or  channel,  called  the  inguinal  canal, 
which  extends  from  the  point  at  which  the 
spermatic  cord  emerges  from  the  abdomen,  (the 
opening  in  the  fascia  transversalis  called  in- 
ternal abdominal  ring)  to  the  external  abdo- 
minal ring.  This  canal  is  bounded  or  covered 
anteriorly  by  the  tendon  of  the  obliquus 
externus;  posteriorly  by  the  fascia  trans- 
versalis and  some  fibres  of  the  tendon  of  the 
transversalis  muscle  towards  the  inner  side ; 
superiorly  by  the  margin  of  the  obliquus  in- 
ternus and  transversalis  muscles  ;  and  inferiorly 
by  the  groove  of  Poupart's  ligament.*  (A  full 
description  of  this  canal  will  be  found  in  the 
article  GROIN,  REGION  OF  THE.) 

3.  Transversalis  ( lumbo-abdominal,  lumbo- 
ili-abdominal).  This  muscle  is  immediately 
under  cover  of  the  obliquus  internus ;  its  name 
is  derived  from  the  transverse  direction  of  its 
fibres.  In  its  general  character  it  resembles 
the  obliqui,  being  like  them  a  muscular  lamella, 
inserted  into  a  tendinous  expansion,  which 
again  is  inserted  into  the  linea  alba.  Supe- 
riorly the  fleshy  fibres  of  this  muscle  are  attach- 
ed by  distinct  bundles  to  the  internal  surface 
of  the  cartilages  of  the  ribs  forming  the  lower 
margin  of  the  thorax,  where  these  bundles  in- 
digitate  with  those  of  the  diaphragm  :  2dly,  in 
the  interval  between  the  last  rib  and  the  crista 

Fig.  4. 


*  "  The  obliquus  internus  corresponds  to  the  in- 
ternal intercostals  by  the  direction  of  its  fibres, 
by  its  being  situated  under  cover  of  the  obliquus 
externus,  and  because  its  fleshy  fibres  extend  much 
further  forwards  than  those  of  the  last-named  mus- 
cle. "— 


ABDOMEN. 


ilii,  the  fibres  arise  from  a  tendinous  lamella, 
which  itself  is  trifoliate  in  its  origin.  This  ten- 
don is  found  as  an  undivided  lamella  between 
the  outer  margin  of  the  quadratus  lamborum  and 
the  commencement  of  the  fleshy  fibres  of  the 
muscle,  extending  vertically  from  the  last  rib 
to  the  crista  ilii.  (  Fig.  4, 1.)  The  three  laminae 
of  which  this  tendon  is  composed  arise  from 
different  portions  of  the  vertebrae  in  the  lumbar 
region  of  the  spine;  the  posterior,  which  is 
thick  and  strong,  and  is  commonly  called 
fascia  lumborum,  arises  from  the  extremities 
of  the  spinous  processes,  and  covers  the  lum- 
bar mass  of  muscles.  (Fig.  4,  g.)  The  mid- 
dle, which  is  weak,  is  attached  to  the  apices  of 
the  transverse  processes  ;  it  lies  in  front  of  the 
lumbar  mass  and  behind  the  quadratus  lumbo- 
rum  (Jig.  4,  h);  and  the  anterior  arises  from  the 
pedicles  which  connect  the  transverse  processes 
to  the  bodies  of  the  vertebrae,  and  covers  the 
quadratus  lumborum  muscle  in  front  (Jig.  4, 
f).  Inferiorly,  the  transversalis  muscle  at- 
taches itself  to  the  inner  lip  of  the  crista  ilii 
for  its  three  anterior  fourths,  and  to  the  ex- 
ternal third  or  half  of  Poupart's  ligament,  cor- 
responding to  the  attachments  of  the  obliquus 
internus.  The  fleshy  fibres  of  the  muscle  pass 
from  these  several  points  of  attachment  trans- 
versely inwards,  the  middle  being  the  longest, 
and  the  superior  the  shortest,  and  are  in- 
serted into  the  outer  convex  margin*  of  a 
tendinous  aponeurosis,  which  extends  to  the 
linea  alba.  This  aponeurosis  is  intimately 
connected  with  the  posterior  division  of  that 
of  the  obliquus  internus  for  an  extent  corre- 
sponding to  the  three  superior  fourths  of 
the  rectus  muscle,  behind  which  both  pass  to 
be  inserted  into  the  ensiform  cartilage  and 
linea  alba,  (Jig.  4,  a,)  forming  the  posterior 
wall  of  the  sheath  of  the  rectus.  Inferiorly,  as 
we  have  already  remarked,  these  conjoined 
tendons  go  together  in  front  of  the  rectus,  and 
are  inserted  into  the  inferior  fourth  of  the  linea 
alba  and  into  the  pubis.  At  the  inner  extre- 
mity of  the  inguinal  canal,  it  will  be  seen  by 
carefully  raising  up  the  spermatic  cord,  that 
this  union  of  the  tendons  of  these  two  muscles 
ceases,  and  we  can  trace  the  fibres  of  the  trans- 
versalis tendon  passing  down  in  a  curved  direc- 
tion, more  curved  as  they  are  more  external, 
and  insinuating  themselves  behind  the  cord  to 
be  inserted  into  Gimbernat's  and  Poupart's 
ligament  for  about  its  ^xternal  third  or  fourth. 
This  mode  of  insertion  of  the  transversalis  ten- 
don was  first  described  by  Sir  Astley  Cooper,  f 
and  these  fibres  were  by  him  called  thejblded 
fibres  of  the  transversalis.  They  adhere  to  the 
subjacent  fascia,  (fascia  transversalis,)  and  add 
to  the  strength  of  the  inner  portion  of  the  pos- 
terior wall  of  the  inguinal  canal.  They  cor- 
respond, in  a  great  measure,  to  the  external 
abdominal  ring,  and  may  be  counted  as  one  of 
the  obstacles  provided  against  the  direct  descent 
of  a  hernia. 

Such  is  unquestionably  the  usual  mode  of 

*  This  margin  forms   the    linea    semilunaris    of 
Spigelius. 

t  Cooper  on  the  Testicle,  p.  35. 


insertion  of  the  tendon  of  the  transversalis 
muscle ;  but  Mr.  Guthrie  has  lately  called  the 
attention  of  anatomists  to  a  variety  which  it 
is  important  to  know,  although  it  cannot  be 
of  frequent  occurrence.  In  this  variety  the 
spermatic  cord  appears  to  pass  through  a  slit  in 
the  inferior  margin  of  the  transversalis  muscle, 
so  that  a  bundle  of  muscle  passes  behind  as 
well  as  before  the  cord  ;  the  posterior  one  end- 
ing in  tendinous  fibres,  which,  like  the  folded 
fibres  above  described,  are  inserted  into  Pou- 
part's ligament.*  It  is  very  generally  believed 
that  the  inferior  fibres  of  this  muscle  contribute, 
as  well  as  those  of  the  obliquus  internus,  to 
form  the  cremaster.  The  two  muscles  are  so 
closely  connected  externally  by  their  inferior 
margins,  that  it  is  natural  to  suppose  that  both 
do  send  fibres  to  the  cremaster.  Sir  Astley 
Cooper  expresses  the  relation  of  the  cremaster 
to  these  two  muscles  in  the  clearest  way,  when 
he  says  that  it  arises  from  Poupart's  ligament 
within  the  inguinal  canal,  and  there  blends  with 
some  of  the  fibres  of  both  these  muscles.f 

A  thin  layer  of  cellular  tissue  covers  the 
transversalis  muscle,  and  separates  it  from  the 
obliquus  internus.  At  its  superior  margin  it 
is  intimately  related  to  the  diaphragm,  and 
some  of  its  fibres  seem  to  be  continuous  with 
it :  posteriorly,  by  the  triple  partition  of  its 
tendon,  it  ensheaths  the  lumbar  muscles,  and  it 
lies  upon  the  fascia  transversalis,  which,  with  a 
layer  of  cellular  tissue,  separates  it  from  the 
peritoneum.  | 

4.  Rectus  abdominis  (ster no-pub ien).  After 
the  superficial  fascia  has  been  removed  so  as 
to  expose  the  aponeurosis  of  the  external  ob- 
lique, the  recti  muscles  are  seen  on  either  side 
of  the  middle  line  covered  by  this  aponeurosis, 
which  it  is  necessary  to  slit  up  in  order  to  ex- 
pose the  muscles.  The  rectus  owes  its  name 
to  the  perpendicular  course  of  its  fibres,  which 
pass  from  the  pubis  to  the  thorax,  nearly 
parallel  to  the  middle  line.  It  is  long  and 
narrow ;  however,  its  breadth  increases  as  it 
advances  upwards,  and  as  it  increases  in  breadth 
it  diminishes  in  thickness.  At  the  pubis  the 
muscle  has  its  most  fixed  point  of  attachment, 
whence  it  is  generally  said  to  have  its  origin 
there:  it  arises  by  a  short  tendon  from  the 
symphysis  of  the  pubis;  this  tendon  is  very 
narrow  at  its  origin,  but  soon  expands,  and 
unites  with  the  muscular  fibres,  which  pass 
vertically  upwards  to  the  lower  margin  of 
the  thorax,  where  the  muscle  is  considerably 
increased  in  breadth,  and  divides  into  three 
portions;  the  first  or  internal  one  is  inserted 
into  the  costoxiphoid  ligament  and  cartilage 
of  the  seventh  rib ;  the  middle,  larger  than 
the  preceding,  into  the  cartilage  of  the  sixth 
rib  at  its  inferior  edge  and  anterior  surface; 

*  Guthrie  on  Inguinal  and  Femoral  Hernia,  pp. 
11,  12,  13,  4to.  Lond.  1833. 

t  Op.  cit.  p.  38. 

t  "  The  transversalis  corresponds,  by  the  direction 
of  its  fibres,  to  the  '  triangularis  sterni ;'  also,  by  its 
situation,  by  the  attachment  of  its  external  edge  to 
the  internal  surface  of  the  ribs,  and  by  that  of  its 
internal  edge  to  the  sternum  and  linea  alba." — 
Mechel. 


ABDOMEN. 


and  the  external,  the  largest  of  the  three, 
into  the  inferior  edge  of  the  cartilage  of  the 
fifth  rib.  This  muscle  is  remarkable  for  its 
tendinous  intersections,  which  cut  the  fibres  at 
right  angles,  and  are  called  linear  transverse.  ;* 
they  vary  in  number  from  three  to  five,  and  are 
always  more  numerous  above  than  below  the 
umbilicus.  In  general  there  is  one  on  a  level 
with  the  umbilicus;  the  superior  one  being 
about  an  inch  below  the  superior  attachment  of 
the  muscle,  and  a  third  midway  between  these 
two :  when  a  fourth  and  a  fifth  exist,  they  are 
below  the  umbilicus.  They  adhere  to  the  an- 
terior wall  of  the  sheath  closely,  and  but  very 
slightly  or  not  at  all  to  the  posterior.  Some- 
times the  intersection  does  not  go  completely 
through  the  thickness  of  the  muscle  so  as  to 
appear  on  its  posterior  surface,  and  thus  the 
posterior  fibres  are  longer  than  the  anterior; 
but  as  Bichat  remarks,  it  never  happens  that 
any  of  the  muscular  fibres  pass  from  one  extre- 
mity of  the  muscle  to  the  other  without 
uniting  at  least  one  of  these  intersections. 
Sometimes,  too,  the  intersection  does  not  go 
through  the  breadth  of  the  muscle,  and  this  is 
generally  the  case  with  that  below  the  umbili- 
cus. The  effect  of  these  intersections  is  to 
convert  the  muscle  into  so  many  distinct  bellies, 
each  of  which  has  its  proper  action,  and  is,  as 
Beclard  asserts,  provided  with  a  separate 
nerve.f 

The  rectus  muscle  is  enveloped  in  a  fibrous 
sheath,  the  mode  of  formation  of  which  the 
reader  must  have  collected  from  the  description 
of  the  oblique  muscles.  The  anterior  wall  of 
this  sheath  is  formed  by  the  aponeurosis  of  the 
external  oblique  alone  over  the  chest,  and  by  the 
same  aponeurosis  and  the  anterior  layer  of  that  of 
the  internal  oblique,  from  the  xiphoid  cartilage 
to  the  inferior  fourth  of  the  muscle  ;  (both  which 
aponeuroses  over  the  internal  half  of  the  muscle 
are  so  adherent  to  each  other  as  to  form  but 
one  lamina;)  and  in  its  inferior  fourth  by  the 
conjoined  aponeuroses  of  the  two  obliqui  and 
transversalis. 

The  posterior  wall  of  the  sheath  is  deficient 
superiorly  where  the  muscle  covers  the  carti- 
lages of  the  ribs  with  which  it  is'  in  contact, 
and  inferiorly  for  a  space  corresponding  to  the 
inferior  fourth  of  the  muscle.  So  much  of  it  as 
exists  is  formed  by  the  tendon  of  the  transver- 
salis and  the  posterior  lamina  of  that  of  the 
internal  oblique,  so  that  the  rectus  appears  to 
have  passed  at  its  inferior  extremity  through  a 
transverse  slit  in  these  conjoined  tendons,  so  as 
to  get  between  them  and  the  peritoneum. 

The  rectus  muscle  covers,  at  its  superior  ex- 
tremity, the  cartilages  of  the  two  last  true  ribs 
and  a  part  of  those  of  the  two  first  false,  and 
also  the  xiphoid  appendix.  The  internal  mam- 
mary and  epigastric  arteries  are  found  behind  it 
in  the  sheath. 

Between  the  recti  muscles  is  the  fibrous  cord 
called  linea  alba,  produced  by  the  interlace- 

*  Also  called  enervations.—  Window.  They  are, 
says  Meckel,  incontestahly  incomplete  repetitions  of 
the  ribs  in  the  walls  of  the  abdomen. 

t  Hence  Meckel  classes  it  among  the  polygastric 
muscles. 


ment  of  the  aponeuroses  of  the  opposite  sides, 
noted  in  surgery  as  being  in  its  inferior  half  the 
seat  of  the  operations  of  paracentesis  abdominis, 
paracentesis  vesicse  supra  pubem,  the  supra- 
pubic  lithotomy,  and  the  Caesarean  operation. 
This  cord  extends  from  the  xiphoid  cartilage  to 
the  symphysis  pubis,  with  the  anterior  liga- 
ment of  which  articulation  it  is  identified.  It 
does  not  present  the  same  breadth  in  its  whole 
course,  being  broader  in  the  umbilical  region 
than  elsewhere.  In  this  region  we  find  in  the 
linea  alba  the  perforation  which  gave  passage  to 
the  umbilical  vessels  in  the  foetus  and  the 
urachus,  and  through  which  the  fibrous  remains 
of  those  vessels  pass  to  be  inserted  into  the 
skin,  whereby  is  formed  the  cutaneous  depres- 
sion which  marks  the  situation  of  this  opening. 
In  the  adult  the  umbilicus  may  be  considered 
as  a  point  of  considerable  strength  ;  in  the  esti- 
mation of  some  it  is  the  strongest  point  in  the 
abdominal  parietes :  in  dissecting  away  the  skin 
at  this  point,  we  find  subjacent  to  it  a  very  con- 
densed cellular  tissue,  to  which  and  to  the 
skin  the  fibrous  cords  into  which  the  umbilical 
vessels  have  degenerated  adhere  closely ;  these 
cords,  too,  adhere  not  only  to  the  skin,  but 
likewise  to  the  margin  of  the.  fibrous  ring 
through  which  they  pass.  "  The  umbilical 
opening,  therefore,"  says  Scarpa,  "  in  the 
infant  two  months  after  birth,  and  still 
more  in  the  adult,  is  not  only  like  the  other 
natural  openings  of  the  abdomen,  strength- 
ened internally  by  the  application  of  the  peri- 
toneum and  of  the  cellular  substance,  and  on 
the  outside  by  the  common  integuments,  but  it 
is  likewise  plugged  up  in  the  centre  by  the 
three  umbilical  ligaments  and  by  the  urachus; 
these  ligaments  form  a  triangle,  the  apex  of 
which  is  fixed  in  the  cicatrix  of  the  in  teguments 
of  the  umbilicus,  the  base  in  the  liver,  in  the 
two  ilio-lumbar  regions,  and  in  the  fundus  of 
the  urinary  bladder ;  by  this  triangle  is  formed 
a  strong  and  elastic  bridle,  capable  of  itself 
alone  of  opposing  a  powerful  resistance  to  the 
viscera  attempting  to  open  a  passage  through 
the  aponeurotic  ring  of  the  umbilicus,  which 
apparatus  does  not  exist  at  the  inguinal  ring  or 
femoral  arch."* 

In  the  foetus  the  ring  of  the  umbilicus  is 
proportionally  larger  than  at  any  period  after 
birth  when  the  cicatrix  is  fully  formed :  it  is, 
however,  at  the  full  term,  or  even  at  the  seventh 
or  eighth  month,  and  in  the  healthy  state  of  the 
parts,  equally  filled  up  by  the  umbilical  vessels 
and  urachus,  and  we  would  say  is  equally 
capable  of  resisting  intestinal  protusion  as  at 
any  subsequent  period.  Hence  it  may  be  in- 
ferred that  congenital  umbilical  ruptures  are 
always  of  very  early  date,  being  attributable  to 
the  persistence  of  the  opening  at  the  umbilicus, 
and  the  continuance  in  it  of  the  intestinal  pro- 
longation which  exists  there  naturally  at  a  very 
early  period.  It  may  likewise  be  inferred  that 
the  rupture  in  the  adult  can  much  more  easily 
occur  in  the  vicinity  of,  than  through  the  umbi- 
lical ring;  and  experience  confirms  this  deduc- 
tion from  the  anatomy  of  the  parts. 

*   Scarpa  on  Hernia,  p.  373. 


10 


ABDOMEN. 


Above  the  umbilicus  the  linea  alba  is  from 
two  to  four  lines  broad  in  the  greater  part  of  its 
extent;  and  below  the  umbilicus  it  gradually 
tapers  down  to  the  pubis,  at  the  same  time  in- 
creasing in  thickness.* 

5.  Pyramidalis  ( pubio-sub-umbilical ) .  At 
the  inferior  extremity  of  the  recti,  and  separa- 
ting their  origin,  are  two  small  muscles  of  a 
pyramidal  form;  their  bases  are  inferior,  and 
attached  to  the  symphysis  and  body  of  the 
pubis,  and  uniting  ligaments,  and  their  apices 
superior  and  inserted  into  the  linea  alba  by 
small  tendons,  from  two  to  three  inches  above 
the  symphysis  pubis.  Each  muscle  is  enve- 
loped in  a  distinct  sheath,  and  lies  a  little  more 
prominently  than  the  origin  of  the  rectus  of  the 
same  side.  These  muscles  are  not  unfrequently 
absent.  Sometimes,  on  the  contrary,  there  have 
been  two  on  one  side  and  one  on  the  other,  or 
even  two  on  each  side.f 

The  muscles  which  enter  into  the  composi- 
tion of  the  posterior  wall  of  the  abdomen  are 
chiefly  those  which  occupy  the  lumbar  region 
of  the  back,  filling  up  that  empty  space  which 
in  the  skeleton  is  observed  on  each  side  of  the 
spinal  column  between  the  crista  ilii  and  the 
last  rib.  In  dissecting  from  behind  forwards 
in  this  region,  having  removed  the  skin  and  lax 
cellular  tissue  already  described,  we  come  upon 
the  strong  fibrous  expansion,  the  fascia  lumbo- 
rum.  This  has  extensive  osseous  attachments, 
and  thus  firmly  binds  down  the  subjacent  mus- 
cles. When  it  is  removed,  the  lumbar  portions 
of  the  sacrolumbalis  and  longissimus  dorsi,  and 
a  little  of  the  spinalis  dorsi,  are  brought  into 
view,  the  two  former  of  which  are  described  by 
some  as  a  single  muscle — the  sacrospinalis. 
The  external  of  these  muscles  is  the  sacrolum- 
balis, and  its  outer  margin  may  be  said  to  con- 
stitute the  limit  of  the  posterior  wall  of  the 
abdomen  in  that  direction.  In  this  situation 
the  posterior  and  middle  layers  of  the  tendon 
of  the  transversal  is  separate  from  each  other  to 
ensheath  these  muscles,  the  posterior  layer 
forming  the  fascia  lumborum.  We  must  refer 
to  the  article  BACK  for  a  particular  description 
of  these  muscles. 

When  the  lumbar  mass  of  muscles  (as  the 
three  preceding  have  been  called)  has  been  re- 
moved, the  next  part  brought  into  view  is  the 
anterior  layer  of  their  fibrous  sheath  formed  by 
the  middle  lamina  of  the  transversalis  tendon, 
which  is  inserted  into  the  apices  of  the  trans- 
verse processes.  This  lamina  is  thin  and  semi- 
transparent,  so  that  the  fibres  of  the  muscle 

*  "  The  linea  alba  performs  the  same  office  in 
the  abdomen  as  the  sternum  does  in  the  thorax,  with 
this  only  difference,  that  it  is  not  formed  of  bone. 
The  anterior  tendons  of  the  broad  muscles  are  at- 
tached to  it,  in  the  same  way  that  the  cartilages  of 
the  ribs  are  articulated  with  the  sternum,  and  the 
difference  of  tissue  which  exists  between  it  and  the 
sternum  is  attributable  to  the  general  difference  of 
structure  between  the  abdominal  and  pectoral  cavi- 
ties, the  latter  being  formed  almost  entirely  of 
osseous  parts,  whilst  the  walls  of  the  former  are 
fleshy  and  tendinous/' — Meckel. 

t  Meckel  says  that  this  muscle  rarely  presents 
anomalies  ;  in  this  he  must  be  mistaken,  as  its  ab- 
sence is  ceitainly  not  a  rare  occurrence. 


which  lies  immediately  before  it,  are  seen 
through  it.  This  muscle  is  the 

Quadratus  lumborum  (ilio-costal,  ilio-lumbi- 
costal).  The  term  quadratus  is  applied  to  this 
muscle,  more  from  its  quadrilateral  form  than 
from  any  nearer  resemblance  to  a  square,  in- 
asmuch as  all  its  sides  are  unequal.  The  most 
fixed  attachment  of  this  muscle  is  its  inferior, 
where  it  is  inserted  by  tendinous  fibres  into  the 
iliolumbar  ligament  and  into  the  inner  lip  of  the 
crista  ilii  for  about  an  inch  to  the  outer  side  of 
the  insertion  of  that  ligament.  From  these  points 
the  fibres  proceed  vertically  upwards,  the  ex- 
ternal ones  going  to  be  inserted  into  the  inferior 
margin  of  the  last  rib  for  nearly  its  entire 
length,  and  the  internal  fibres,  those  in  parti- 
cular which  are  attached  to  the  ligament,  ter- 
minating by  four  aponeurotic  tongue-like  bun- 
dles, which  are  inserted  into  the  anterior  surface 
of  the  transverse  processes  of  the  four  superior 
lumbar  vertebrae  near  their  bases.  The  several 
bundles  which  end  in  these  tongue-like  pro- 
cesses vary  in  length ;  those  which  are  external 
being  the  longest,  as  going  to  higher  vertebrae. 
This  muscle  is  covered  on  its  anterior  or  abdo- 
minal surface  by  the  anterior  lamina  of  the 
tendon  of  the  transversalis  muscle,  by  which  it 
is  separated  from  the  diaphragm  as  well  as 
from  the  psoas  magnus.*  The  last  dorsal 
nerve  and  the  first  two  branches  of  the  lumbar 
plexus,  pass  between  the  quadratus  and  the 
aponeurotic  lamina  which  covers  it. 

Psoas  magnus,  (-»]/oa,  lumbus)  (prelombo, 
trochanterien,  lumbaris.)  The  greatest  por- 
tion of  this  muscle  belongs  to  the  abdominal 
region ;  it  lies  along  the  side  of,  not  only  the 
lumbar  but  also  of  a  small  portion  of  the  dorsal 
region  of  the  spine,  lodged  in  the  angle  between 
the  transverse  processes  and  bodies.  It  passes 
as  high  up  as  the  twelfth  dorsal  vertebra,  to  the 
body  of  which  as  well  as  to  those  of  the  four  suc- 
ceeding lumbar  vertebrae,  and  to  their  interven- 
ing fibro-cartilages,  the  muscle  is  attached :  it 
likewise  is  attached  to  the  bases  of  the  corres- 
ponding transverse  processes,  so  that  the  inter- 
vals between  the  portions  that  are  attached  to 
the  bodies,  and  those  to  the  transverse  processes, 
correspond  to  the  intervertebral  foramina  or 
points  of  exit  of  the  lumbar  nerves,  the  an- 
terior branches  of  which  plunge  at  once  into 
the  substance  of  the  psoas  muscle  to  form  the 
lumbar  plexus.  The  several  bundles  which 
thus  take  their  origin  from  the  vertebrae  form 
a  thick  rounded  muscle,  which  passes  nearly 
vertically  downwards,  inclining  a  little  out- 
wards, over  the  brim  of  the  true  pelvis,  so  as 
often  to  appear  to  encroach  upon  the  circum- 
ference of  the  upper  outlet  of  that  cavity.  A 
little  way  above  Poupart's  ligament  the  mus- 
cular fibres  are  inserted  around  a  strong  thick 
tendon.  This  tendon,  which  had  commenced 
high  up  by  distinct  portions  in  the  interior  of 
the  muscle,  passes  under  Poupart's  ligament 
over  the  horizontal  ram  us  of  the  pubis.  It 
descends  over  the  capsular  ligament  of  the  hip- 


*  See  Jig.  4,y;  see  also  fig.  5,  where  on  one  side 
the  muscle  has  been  removed  from  between  the 
laminae  of  the  transversalis  tendon. 


ABDOMEN. 


11 


joint  (from  which  as  well  as  from  the  ramus 
of  the  pubis  it  is  separated  by  a  bursa)  over 
the  head  and  along  the  inner  side  of  the  neck 
of  the  femur,  and  is  inserted  into  the  posterior 
part  of  the  trochanter  minor  at  its  base,  being 
separated  by  a  small  bursa  from  the  surface  of 
that  process.  As  the  tendon  is  passing  over 
the  ramus  of  the  pubis,  it  receives  by  its  outer 
margin  a  series  of  fibres  from  the  iliacus  in- 
ternus  muscle.  At  its  superior  portion  the 
psoas  muscle  is  covered  by  a  thin  fibrous  ex- 
pansion, which  is  attached  on  the  one  hand  to 
the  apices  of  the  transverse  processes,  and  on 
the  other  to  the  bodies  of  the  upper  lumbar 
vertebrae  ;  this  expansion,  the  arcus  interior  of 
Senac  and  Haller,*  also  called  ligamentum 
arcitatum,  separates  the  psoas  from  the  dia- 
phragm. Below  this  the  psoas  muscle  is 
covered  with  a  lax,  and  in  some  degree  fatty 
cellular  tissue,  which  separates  the  muscle  from 
the  kidney  externally,  and  from  the  peritoneum 
and  ureter  within,  excepting  where  the  psoas 
parvus  covers  it,  and  on  the  right  side  where  the 
vena  cava  lies  upon  it.  Along  its  internal  margin 
are  the  lumbar  portion  of  the  sympathetic,  the 
crura  of  the  diaphragm,  more  especially  on  the 
left  side,  and  on  this  side  too  the  aorta  ap- 
proaches a  little  its  internal  margin.  The 
common  and  external  iliac  arteries  and  veins 
lie  along  the  internal  margin  of  the  pelvic 
portion  of  the  muscle,  which  is  covered  by  the 
fascia  iliaca.  The  several  branches  of  the 
lumbar  plexus  issue  from  this  muscle  at  its 
external  margin,  and  the  genito-crural  nerve 
descends  in  front  of  it  inferiorly.  We  refer 
to  the  article  on  the  muscles  of  the  thigh  for  a 
further  account  of  this  muscle,  its  relations  in 
the  upper  part  of  the  thigh,  and  its  actions. 

Psoas  parvus,  (prelombo-pubien).  This 
muscle  is  similar  to  the  psoas  magnus  in 
course  and  position.  It  is  very  much  elongated, 
its  fleshy  portion  being  small  and  tapering.  Su- 
periorly it  is  attached  to  the  body  of  the  first 
lumbar  vertebra,  and  to  the  intervertebral  sub- 
stance between  it  and  the  last  dorsal,  and 
sometimes  to  the  body  of  the  last  dorsal  ver- 
tebra. The  fleshy  belly  soon  ends  in  a  flattened 
tendon,  which  descends  obliquely  downwards 
and  outwards  over  the  anterior  surface  of  the 
psoas  magnus,  and  at  its  inferior  extremity  ex- 
pands considerably,  and  is  inserted  along  the 
linea  ilio-pectinea  near  the  junction  of  the 
ilium  and  pubis.  An  expansion  from  the 
margins  of  this  tendon  becomes  united  on  the 
outside  to  the  fascia  iliaca,  and  on  the  inside 
to  the  internal  portion  of  the  same  fascia  which 
covers  the  great  psoas,  and  passes  beneath  the 
iliac  vessels  to  become  united  at  the  brim  of 
the  pelvis  to  the  pelvic  fascia. 

We  must  not  omit  to  state  that  the  crura  of 
the  diaphragm,  as  they  descend  over  the  bodies 
of  the  lumbar  vertebrae,  (see  DIAPHRAGM,)  may 
be  regarded  as  entering  into  the  formation  of 
the  posterior  wall  of  the  abdomen.  The  inferior 
wall  of  the  abdomen  is  not  devoid  of  muscle, 
although  those  muscles  can  exercise  very  little,  if 


*  Vid.  Haller  Icon.  Scpti  Transversi.  Op.  Minora, 
torn.  1. 


any  influence  upon  the  contents  of  the  cavity. 
The  iliac  fossa  affords  a  large  surface  for  the 
attachment  of  one  of  the  principal  muscles 
connecting  the  thigh  with  the  trunk.  This 
muscle  is  named 

Iliacus  internus,  (iliaco-trochanterien.)  This 
muscle  fills  up  the  iliac  fossa,  to  the  whole  of 
whose  concavity  as  well  as  to  its  margin,  and 
the  two  anterior  spinous  processes  of  the  ilium 
and  the  interval  between  them,  its  fibres  are 
attached.  From  these  several  points  of  origin 
the  fibres  converge  to  form  a  thick  and 
broad  belly,  which  passes  over  the  upper  part 
of  the  acetabulum  and  horizontal  ramus  of  the 
pubis,  filling  up  the  external  portion  of  the 
upace  between  that  bone  and  Poupart's  ligament ; 
and  it  is  inserted,  as  we  have  already  observed, 
into  the  outer  margin  of  the  tendon  of  the 
psoas  magnus,  which  is  for  thgt  reason  gene- 
rally described  as  the  common  tendon  of  the 
psoas  and  iliacus.  The  anterior  surface  of  this 
muscle  is  traversed  by  two  of  the  external 
branches  of  the  lumbar  plexus  (inguino-cuta- 
neous),  and  the  anterior  crural  nerve  passes 
between  its  internal  margin  and  the  psoas 
magnus. 

The  superior  wall  of  the  abdomen  is  entirely 
formed  by  the  muscular  vault  of  the  diaphragm, 
which  by  its  contraction  and  relaxation  exer- 
cises a  considerable  influence  on  the  abdominal 
contents,  and  causes  very  obvious  changes  in  the 
form  of  the  cavity.  The  concavity  of  this  vault 
is  towards  the  abdomen,  and  is  greater  on  the 
right  side  than  on  the  left,  in  consequence,  as 
it  is  said,  of  the  presence  of  the  liver  on  that 
side.  It  is  through  the  several  openings  in  this 
wall  that  a  communication  is  established  be- 
tween the  thorax  and  abdomen.  The  largest  of 
these  openings  are,  that  on  the  right  side, 
which  is  completely  tendinous,  for  the  passage 
of  the  vena  cava;  the  opening  for  the  reso- 
phagus;  and  that  for  the  aorta;  in  addition 
to  these  there  is  a  small  one  behind  the 
centre  of  the  xiphoid  appendix  formed  by  a 
divarication  of  the  anterior  fibres  of  the  dia- 
phragm, through  which  the  cellular  tissue  of 
the  anterior  mediastinum  communicates  with 
the  abdominal  subserous  tissue.  There  are, 
moreover,  openings  for  the  transmission  of  the 
splanchnic  nerves,  and  the  continued  trunks  of 
the  sympathetics,  as  well  as  of  branches  of  the 
phrenic  arteries  and  nerves,  and  the  abdominal 
branches  of  the  internal  mammary.  The  par- 
ticular description  of  this  muscle  will  be  given 
under  the  article  DIAPHRAGM. 

4.  The  next  element  which  enters  into  the 
formation  of  the  abdominal  parietes  is  a  fibro- 
cellular  expansion,  which,  varying  in  density 
in  different  situations,  lines  the  whole  internal 
surface  of  the  muscular  walls.  It  is  strongest 
and  exhibits  most  of  the  real  fibrous  character 
in  the  iliac  region  on  the  anterior  wall,  and 
over  the  iliac  fossa  in  the  inferior.  In  the 
former  situation  it  has  received  the  name  of 
fascia  transversalis,  which  was  applied  to  it  by 
'  Sir  A.  Cooper  in  consequence  of  its  close  con- 
nexion with  the  transversalis  muscle  :  in  the 
latter,  it  is  called  the  fascia  iliaca,  from  its 
connexion  with  the  iliac  fossa  and  muscle. 


12 


ABDOMEN. 


The  fascia  transversalis  is  best  seen  by  re- 
moving the  muscles  which  lie  anterior  to  it :  it 
is  then  distinctly  observed  to  extend  from  the 
outer  margin  of  the  rectus  muscle  internally 
over  the  posterior  surface  of  the  anterior  wall  of 
the  abdomen,  and  gradually  to  assume  the 
character  of  a  thin  but  condensed  cellular  la- 
mella over  the  abdominal  surface  of  the  lateral 
wall :  it  may,  however,  be  traced  internally  as 
far  as  the  linea  alba  behind  the  rectus  muscle, 
but  here  it  is  extremely  thin,  and  has  totally 
lost  the  fibrous  character.  Inferiorly  this  fascia 
adheres  to  Gimbernat's  ligament  and  to  the 
reflected  margin  of  Poupart's,  from  which  it  is 
said,  by  some  French  anatomists,  to  originate. 
Along  the  line  of  Poupart's  ligament  and  ex- 
ternal to  it  along  the  crista  ilii,  this  fascia  is 
united  with  the  fascia  iliaca,  the  union  be- 
ing indicated  by  a  white  opaque  line  formed 
by  a  thickening  of  the  membrane,  taking  the 
course  of  Poupart's  ligament  and  the  crista  ilii, 
except  where  it  is  interrupted  for  the  passage  of 
vessels  or  other  parts.  Superiorly,  the  fascia 
transversalis  also  degenerates  into  a  cellular 
lamella,  which  passes  on  the  transversalis 
muscle  to  the  diaphragm.  It  is  for  a  short 
distance  above  Poupart's  ligament  that  this 
fascia  demands  most  attention ;  here  it  forms  the 
posterior  wall  of  the  inguinal  canal,  and  at  a 
point  a  little  external  and  superior  to  the  middle 
of  Poupart's  ligament  it  presents  an  opening  or 
separation  of  its  fibres,  through  which  the  sper- 
matic vessels  and  vas  deferens  united  by  lax 
cellular  tissue  pass  into  the  inguinal  canal, 
carrying  around  them  a  funnel-shaped  mem- 
brane which  seems  to  be  a  prolongation  from 
or  continuation  of  the  margins  of  this  opening, 
but  which  is  in  texture  merely  a  condensed  cel- 
lular layer.  This  prolonged  membrane  is  the 
first  covering  which  the  spermatic  cord  receives 
upon  its  formation,  which  takes  place  as  its 
several  constituent  parts  meet  at  the  opening  or 
slit  in  the  fascia  transversalis ;  it  immediately 
invests  the  cellular  tissue  connecting  these  parts, 
which  is  the  tunica  vaginalis  of  the  cord ;  as 
it  proceeds,  the  cremaster  muscle  adheres  to  it 
from  the  external  oblique  and  transversalis 
muscles,  and  this  again  receives  at  its  exit 
through  the  external  abdominal  ring  another 
cellular  expansion,  to  which  we  have  already 
alluded. 

The  opening  or  slit  in  the  fascia  transversalis 
which  we  have  just  described  is  denominated 
by  anatomists  the  internal  abdominal  ring, 
although,  if  we  speak  with  reference  to  the  mid- 
dle line,  it  is  external  to  the  opening  in  the 
tendon  of  the  obliquus  externus,  which  is  called 
the  external  ring.  It  would  certainly  be  more 
consistent  with  the  ordinary  use  of  these  ad- 
jectives in  anatomy  to  reverse  their  application, 
or  if  the  term  anterior  were  applied  to  the  ex- 
ternal ring,  and  posterior  to  the  internal,  every 
purpose  would  be  answered. 

The  direction  of  the  internal  abdominal  ring 
is  vertical  and  inclined  very  slightly  outwards. 
When  the  fibrous  character  of  the  fascia  trans- 
versalis is  obvious,  we  can  generally  observe 
two  very  distinct  portions  of  it,  one  on  each 
side  of  the  ring.  The  fibres  of  the  external 


portion  pass  upwards  and  inwards ;  those  of 
the  internal  portion,  which  are  generally  stronger 
and  more  developed  than  in  the  external,  pass 
upwards  and  outwards  so  as  to  decussate  with 
the  external  fibres  at  the  upper  extremity  of  the 
ring.  The  outer  margin  of  this  internal  portion 
often  presents  towards  the  ring  a  lunated  ap- 
pearance, over  which  the  vas  deferens  turns  at  a 
sharp  angle  ;  it  can  be  best  seen  by  examining 
the  parts  from  behind  after  the  peritoneum  has 
been  removed.*  The  fascia  transversalis  is 
continued  upwards  along  the  posterior  and 
lateral  surface  of  the  abdominal  muscles  and 
over  the  diaphragm  under  the  form  of  a  fine 
lamina  of  very  condensed  cellular  membrane, 
which  adheres  pretty  closely  to  the  muscles, 
but  especially  to  the  diaphragm,  where  it 
seems  to  be  incorporated  with  the  proper  cel- 
lular covering  of  that  muscle.  We  refer  to 
the  article  GROIN,  REGION  OF  THE,  for  further 
particulars  respecting  the  fascia  transversalis. 

In  the  iliac  fossa  we  find  a  very  distinct 
fibrous  expansion  covering  the  whole  abdo- 
minal surface  of  the  iliacus  internus  muscle. 
This  is  tine  fascia  iliaca.  It  is  seen  by  raising 
the  peritoneum  and  the  subperitoneal  cellular 
tissue  from  the  fossa.  Inferiorly  this  fascia  is 
connected  with  the  fascia  transversalis  along 
the  line  of  Poupart's  ligament,  except  where 
that  connexion  is  interrupted  by  the  passage  of 
the  vessels  under  the  ligament.  That  space 
comprises  the  interval  between  the  inner  margin 
of  the  tendon  of  the  Psoas  and  Gimbernat's 
ligament;  and  here  the  fascia  lies  close  to  the 
horizontal  ramus  of  the  pubis,  and  passes  be- 
hind the  vessels  into  the  upper  part  of  the  thigh, 
where  it  adheres  to  the  linea  ilio-pectinea, 
and  seems  to  become  continuous  with  the 
fascia  lata.  Externally  the  fascia  iliaca  is  con- 
tinuous with  the  fascia  transversalis  along  the 
crista  ilii,  where  an  opaque  line  indicates  the 
union,  and  just  internal  to  which  it  splits  to 
ensheath  the  circumflexa  ilii  artery.  On  the 
inner  side  of  the  iliac  fossa  this  fascia  unites 
with  the  pelvic  fascia  along  the  brim  of  the 
pelvis,  this  union  being  likewise  indicated  by 
an  opaque  line  similar  to  that  already  noticed 
along  the  crista  ilii.  To  arrive  at  this  point  the 
fascia,  in  proceeding  from  without  inwards, 
passes  over  the  iliacus  internus,  then  over  the 
psoas  magnus  and  parvus,  upon  which  it  is 
thinner  than  elsewhere ;  it  then  passes  behind 
the  iliac  artery  and  vein,  and  arrives  at  the 
pelvic  margin.  Posteriorly  this  fascia  is  con- 
tinuous with  a  thin  and  less  fibrous  expansion 
which  covers  the  psoas  and  quadratus  lumborum 
muscles,  adheres  to  the  ligamentum  arcuaturn, 
and  is  identified  superiorly  with  the  cellular 
expansion  on  the  diaphragm,  and  externally 
with  the  fascia  transversalis. 

It  has  already  been  stated  that  the  iliac  fascia 
passes  behind  the  iliac  vessels.  These  vessels 
have  also  anterior  to  them  a  fibrous  or  cellulo- 
fibrous  expansion,  which  is  connected  on  the 
inner  and  outer  side  to  the  fascia  iliaca.  Some 

*  This  lunated  margin  is  very  well  delineated  by 
Cloquet  in  the  third  figure  of  the  first  plate  annexed 
to  his  work  on  Hernia,  now  translated  by  Mr.  A.M. 
M'YVhinuic. 


ABDOMEN. 


13 


consider  this  as  merely  a  portion  of  the  subperi- 
toneal  cellular  tissue,  but  I  cannot  help  regard- 
ing it  as  a  process  from  the  iliac  fascia  itself  to 
envelope  the  vessels  just  as  that  fascia  envelopes 
the  circumflexa  ilii  artery  between  two  lamina 
at  its  outer  margin.  I  have  never  seen  an  in- 
stance in  which  this  sheath  was  not  perfectly  dis- 
tinct, in  some  cases  it  is  of  considerable  strength, 
but  in  the  majority  weak  and  transparent.  It 
was  this  slveath  which  impeded  Mr.  Abernethy 
in  one  of  his  earliest  operations  for  applying  a 
ligature  to  the  external  iliac  artery.* 

The  connexion  which  the  iliac  fascia  has 
with  the  fascia  transversalis  at  the  crural  arch, 
and  the  relation  both  bear  to  the  iliac  vessels  at 
their  exit  to  become  femoral,  suggested  to  Mr. 
Colles  a  comparison  which  is  constantly  referred 
to  by  anatomists.  "  It  may  be  said  to  resem- 
ble," he  says,  "  a  funnel,  the  wide  part  or 
mouth  of  which  occupies  the  hollow  of  the 
ilium  and  lower  part  of  the  abdominal  muscles, 
and  the  narrow  part  or  pipe  of  which  passes 
downwards  on  the  thigh.  The  mouth  of  this 
funnel  may  be  supposed  to  rise  as  high  as  the 
upper  edge  of  the  iliac  muscle,  and  to  be  turned 
toward  the  cavity  of  the  abdomen  :  the  pipe 
joins  the  wide  part  where  the  external  iliac 
vessels  are  passing  under  Poupart's  ligament, 
and  it  is  continued  down  on  the  thigh,  so  low 
as  to  reach  the  insertion  of  the  saphena  into  the 
femoral  vein."f 

From  the  preceding  sections  it  appears  that 
a  fibro-cellular  expansion  lines  the  whole  in- 
ternal surface  of  the  abdominal  parietes.  It  is 
so  likewise  with  the  pelvis,  and  also  with  the 
thorax.  The  cavity  of  the  cranium,  too,  is 
lined  with  a  fibrous  membrane,,  although  of  a 
different  nature,  and  doubtless  performing  a  dif- 
ferent office. 

5.  Between  the  internal  fibrous  expan- 
sion of  the  abdomen  and  the  peritoneum  is 
a  cellular  tissue,  which  presents  different  cha- 
racters in  each  region ;  it  is  the  subperitoneal 
cellular  tissue.  Along  the  anterior  wall  it  is 
thin  and  fine,  except  inferiorly  opposite  the  in- 
ternal abdominal  ring,  where  it  becomes  more 
abundant,  as  well  as  in  the  hypogastric  region, 
immediately  above  the  pubis.  In  the  iliac 
fossa  and  lumbar  region  it  is  lax  and  abundant, 
especially  in  the  latter,  where  there  is  also  a 
considerable  quantity  of  fat  surrounding  the 
kidney.  In  the  iliac  fossa  this  cellular  tissue 
is  stretched  across  the  crural  ring,  and  forms 
what  Cloquet  describes  under  the  name  of 
septum  crurale.  On  the  superior  wall  it  is  ex- 
tremely fine,  and  in  very  small  quantity.  Im- 
mediately behind  the  sternum,  and  in  the  mid- 
dle line,  this  cellular  tissue  communicates  with 
that  of  the  mediastinum  through  a  separation 
of  the  anterior  fibres  of  the  diaphragm. 

This  subserous  cellular  tissue  forms  the  pri- 
mary covering  of  all  herniae,  which  push  a 
peritoneal  sac  before  them,  and  as  being  the 
fascia  constituting  the  nearest  investment  of  the 
sac,  it  is  generally  called  the  fascia  propria. 

*  Abernethy's  Surgical  Works,  vol.  i.  p.  225. 
t  Colics'  Surgical  Anatomy,  pp.  68,  69. 


Opposite  the  crural  canal  this  cellular  tissue  is 
often  so  abundant,  as,  when  condensed  by  the 
pressure  of  the  hernial  tumour,  to  form  an  ex- 
pansion over  the  sac  of  considerable  thickness. 
Sometimes  it  contains  fat,  and  not  unfrequently 
we  find  a  large  lymphatic  ganglion  in  it,  filling 
up  the  crural  ring. 

6.  Peritoneum. — A  considerable  part  of  the 
abdominal  surface  of  the  walls  of  the  abdomen 
is  lined  by  a  very  fine  transparent  serous  mem- 
brane— the  peritoneum,  which  is  likewise  con- 
nected, to  a  greater  or  less  extent,  with  every 
viscus  within  the  cavity.  In  consequence  of 
this  double  connexion,  it  happens  that  in  various 
situations  the  peritoneum  is  reflected  from  the 
wall  of  the  abdomen  upon  an  adjacent  viscus, 
and  thus  are  produced  various  folds  of  this  mem- 
brane, which  demand  the  attention  of  the  ana- 
tomist. These  folds  are  rendered  distinct  when 
such  a  section  of  the  anterior  abdominal  wall  is 
made  as  without  dividing  them  to  allow  of  it 
being  held  apart  from  the  viscera.  I  shall 
enumerate  these  folds  in  describing  the  relation 
of  the  peritoneum  to  the  several  walls.  The 
anterior  wall  of  the  abdomen  is  entirely  lined 
by  peritoneum,  and  has  in  connexion  with  it 
four  folds,  all  of  which,  as  it  were,  radiate  from 
the  umbilicus.  In  the  adult  these  folds  are 
reflected  round  four  ligamentous  cords  (three 
of  which  are  the  remains  of  bloodvessels  in 
the  foetus),  which  meet  at  the  umbilicus  and 
diverge,  one  upwards,  backwards,  and  to  the 
right  side  (the  obliterated  umbilical  vein), 
two  downwards  and  outwards  towards  Pou- 
part's ligament  on  each  side,  so  as  to  pass 
behind  the  inguinal  canal,  nearly  midway 
between  the  two  rings  (the  obliterated  um- 
bilical arteries),  and  the  fourth  nearly  ver- 
tically downwards  along  the  middle  line  to  be 
inserted  into  the  apex  of  the  bladder  (the  ura- 
chus).  The  four  folds  are  similar  in  direction 
to  that  of  the  fibrous  cords  contained  within 
them  :  the  fold  which  passes  upwards  towards 
the  liver  is  falciform,  the  concavity  being  di- 
rected downwards  and  backwards.  From  its 
connexion  with  the  convex  surface  of  the  liver 
it  is  also  called  the  falciform  ligament  of  the 
liver,  and  the  fibrous  cord  contained  in  its  in- 
ferior margin,  the  ligamentum  teres.  The  in- 
ferior and  external  folds  pass  each  from 
the  umbilicus,  downwards  and  outwards  to 
the  iliac  fossa,  to  a  point  a  little  on  the  inner 
side  of  the  internal  abdominal  ring,  where  it  dis- 
appears, being  continued  externally  over  the 
iliac  fossa,  and  internally  behind  the  rectus 
muscle.  This  fold,  when  stretched  towards 
the  umbilicus,  evidently  forms  the  partition 
between  two  pouches,  the  external  and  in- 
ternal inguinal  pouches,  which  correspond  re- 
spectively to  the  internal  and  external  abdo- 
minal rings,  and  indicate  the  situations  at 
which  make  their  escape  those  two  forms 
of  inguinal  hernia,  which,  from  their  connexion 
with  these  pouches,  are  called  by  Hesselbach 
external  and  internal  inguinal  hernias ;  the  for- 
mer being  that  by  oblique  descent,  the  latter 
that  by  direct  descent. 

The    fourth   or  vertical    fold   indicates   the 


14 


ABDOMEN. 


reflection  of  the  peritoneum  from  the  anterior 
abdominal  wall  upon  the  superior  fundus  and 
posterior  surface  of  the  bladder :  when  that 
viscus  is  empty  and  contracted,  this  fold  dis- 
appears totally  ;  it  is  more  apparent  when  the 
bladder  is  partially  filled,  and  is  still  more 
distinct  in  the  foetus  in  consequence  of  the 
greater  size  of  the  urachus  at  that  period. 
Just  above  the  pubis  the  peritoneum  is  con- 
nected to  the  abdominal  wall  by  a  very  lax 
cellular  tissue;  and  accordingly  when  the  blad- 
der is  much  distended,  the  peritoneum  is 
pushed  upwards,  and  stripped  off  the  abdo- 
minal wall  to  an  extent  proportioned  to  the 
degree  of  distension  of  the  bladder,  so  that  its 
anterior  surface  is  then  in  immediate  contact 
with  the  abdominal  wall,  and  may  be  opened 
with  impunity  so  far  as  the  peritoneum  is  con- 
cerned. 

The  lateral  walls  of  the  abdomen  are  like- 
wise completely  lined  by  peritoneum,  which 
extends  backwards  as  far  as  the  junction  of 
these  walls  with  the  posterior,  where  it  is  re- 
flected from  them  so  as  to  involve  the  ascending 
colon  on  the  right  side  and  the  descending  on 
the  left,  and  here  it  forms  on  each  side  the 
folds  respectively  termed  right  and  left  meso- 
colon.  From  the  right  lateral  wall  the  peri- 
toneum is  continued  upwards  upon  the  dia- 
phragm, and  contributes  to  form  the  right 
lateral  ligament  of  the  liver ;  on  the  left  side 
it  is  continued  in  a  similar  manner  on  the 
diaphragm,  and  in  passing  from  the  spleen  to 
that  muscle  forms  the  fold  called  splenico- 
phrenic. 

The  concave  surface  of  the  diaphragm  is  in 
greatest  part  lined  by  peritoneum  :  the  an- 
terior half  of  the  muscle  is  uninterruptedly 
covered  by  peritoneum,  which  adheres  very 
closely  to  the  central  tendon,  but  is  much  more 
easily  separated  from  the  muscular  portion. 
On  the  right  side  and  in  the  middle,  in  front  of 
the  cesophageal  opening,  the  peritoneum  is  re- 
flected from  the  diaphragm  to  the  liver,  forming 
the  right  lateral,  coronary,  and  left  lateral  liga- 
ments of  that  organ.  The  posterior  half  of 
this  surface  is  likewise  covered  by  peritoneum, 
that  membrane  being  deficient  for  a  little  way 
behind  the  opening  for  the  vena  cava  and 
behind  and  on  each  side  of  the  cesophageal 
and  aortic  openings :  the  crura  of  the  diaphragm 
are  covered  chiefly  on  the  outer  side. 

The  peritoneum  comes  into  immediate  con- 
tact with  the  posterior  abdominal  wall  only  in 
a  very  small  portion  of  its  extent :  in  tracing  it 
on  the  right  side  we  find  it  covering  the  right 
colon,  then  passing  inwards  over  the  kidney 
and  suprarenal  capsule,  the  duodenum  and  vena 
cava,  to  the  eras  of  the  diaphragm  above,  and 
in  the  middle  and  below,  where  it  also  covers 
the  vena  cava,  and  the  renal  vessels,  to  form 
the  right  or  superior  lamina  of  the  mesentery. 
On  the  left  side  it  covers  in  a  similar  manner 
the  left  colon,  the  left  kidney  and  capsule,  and 
that  portion  of  small  intestine  which  projects 
just  to  the  left  of  the  superior  mesenteric  artery, 
which  may  be  regarded  as  the  commencement 
of  the  jejunum ;  below  this  it  manifests  its 


continuity  with  the  layer  of  the  opposite  side 
by  forming  the  left  or  inferior  lamina  of  the 
mesentery.  This  lamina  commences  at  the 
left  side  of  the  body  of  the  second  lumbar 
vertebra;  as  it  descends,  it  gradually  crosses 
more  in  front  of  the  aorta,  so  as  to  terminate 
at  the  right  sacro-iliac  symphysis  ;  the  right 
lamina  is  situated  quite  on  the  right  side  of  the 
spine. 

In  the  iliac  fossae  the  peritoneum  is  in  con- 
nexion with  the  fascia  iliaca,  except  where  it  is 
separated  by  the  coecum  on  the  right  side 
(on  which  side  it  sometimes  forms  a  fold  termed 
mesoccecum,}  and  by  the  sigmoid  flexure  on 
the  left.  Internal  to  these  portions  of  intestine 
on  each  side,  the  peritoneum  covers  the  ex- 
ternal iliac  artery  and  vein,  from  which  it  is 
separated  by  a  very  loose  and  sometimes  adi- 
pose cellular  tissue,  and  by  a  process  of  the 
iliac  fascia,  to  which  allusion  has  already  been 
made. 

From  the  preceding  description  of  the  con- 
nection of  the  peritoneum  with  the  parietes 
of  the  abdomen,  it  will  appear  how  few  are 
the  situations  at  which  the  surgeon  could  cut 
through  any  portion  of  these  walls  without 
risk  of  wounding  the  serous  membrane.  Im- 
mediately above  the  pubis  this  may  be  done 
in  consequence  of  the  abundance  of  cellular 
membrane  there  which  separates  the  serous 
membrane  from  the  wall ;  but  in  the  con- 
tracted state  of  the  bladder  the  operator  must 
proceed  with  the  greatest  caution  :  in  the  dis- 
tended state  of  that  viscus,  however,  the  wall 
of  the  abdomen  is  deprived  of  its  lining  to  an 
extent  proportionate  to  the  height  to  which  the 
bladder  ascends  behind  the  recti  muscles;  and 
accordingly  it  is  under  such  circumstances 
that  the  paracentesis  vesicae  supra  pubem,  and 
the  high  operation  for  the  stone  may  be  per- 
formed with  impunity  to  the  serous  membrane. 
At  the  posterior  wall  an  instrument  may  be 
passed  into  any  part  of  the  posterior  surface 
of  the  kidney  without  injury  to  the  peritoneum ; 
the  pelvis  of  the  kidney,  or  any  part  of  the 
abdominal  course  of  the  ureter,  may  be  opened 
too,  or  the  vena  cava ;  and  by  cutting  into  the 
bodies  of  the  vertebrae,  and  the  muscular  por- 
tion of  the  posterior  wall  in  the  dead  body, 
a  view  of  all  the  parts  which  lie  upon  that  wall 
may  be  obtained  without  at  all  injuring  the 
peritoneum.* 

Further  details  respecting  the  anatomy  of 
the  peritoneum  will  be  found  in  the  article 
under  that  head. 

Vessels  and  nerves  of  the  abdominal  walls. — 
a.  The  arteries. — The  most  important  arterial 
ramifications  are  found  in  the  anterior  wall. 
In  the  superficial  fascia  we  find  the  superficial 
epigastric  artery  or  tegumentary  artery,  which 
exists  as  a  trunk  in  the  iliac  regions.  This 
artery,  arising  from  the  femoral,  pierces  the 
fascia  lata,  and  passes  over  Poupart's  ligament 
upwards  and  inwards,  crossing  the  anterior 

*  The  reader  may  examine  with  advantage,  Lud- 
•wig,  Icones  cavitatum  thoracis  et  abdominis  a  tergo 
apertarum.  Leipzig,  1789. 


ABDOMEN. 


wall  of  the  inguinal  canal  between  the  two 
rings  ;  it  is  distributed  in  the  integuments  and 
fascia  of  the  iliac  and  umbilical  regions,  and  anas- 
tomoses with  its  fellow  of  the  opposite  side,  and 
by  deep  branches  which  pierce  the  aponeuroses, 
with  the  deep  epigastric  artery.  In  the  epigas- 
trium and  hypochondria  the  superficial  fascia 
and  integument  are  supplied  by  cutaneous 
branches  from  the  internal  mammary  and  the 
inferior  intercostals.  The  deep-seated  parts  of 
this  region  are  likewise  supplied  from  the  last- 
named  arteries ;  the  largest  and  most  constant  of 
which  is  the  abdominal  branch  of  the  internal 
mammary,  which  in  the  sheath  of  the  rectus 
supplies  that  muscle,  and  establishes  an  im- 
portant communication  with  the  epigastric : 
this  anastomosis  is  said  to  have  been  known  to 
Galen,  who  by  it  proposed  to  account  for  the 
sympathy  which  exists  between  the  uterus  and 
the  breasts.*  Another  branch  of  the  mammary 
supplies  the  muscles  external  to  the  rectus ;  it 
runs  between  the  obliquus  internus  and  trans- 
versalis,  and  is  lost  in  anastomosing  with  the 
inferior  intercostal,  the  lumbar,  and  the  circum- 
flexa  ilii  arteries. 

Inferiorly,  the  abdominal  wall  is  supplied 
by  two  considerable  and  very  constant  arteries, 
viz.  the  epigastric,  which  may  be  distinguished 
from  the  artery  that  supplies  the  integuments 
by  the  appellation  deep,  and  the  circumflexa  ilii. 
The  epigastric  artery  arises  in  general  from  the 
external  iliac  a  little  way  above  Poupart's  liga- 
ment;   it  at  first  inclines  downwards  to  that 
ligament,  and  then  turns  upwards,  and  directs 
itself  forwards  and  inwards,  crossing  the  iliac 
vein;  it  then  runs  along  the  posterior  surface  of 
the  anterior  wall  of  the  abdomen,  inclosed  be- 
tween the  peritoneum  and  fascia  transversalis, 
at  first  situated  between  the  external  and  inter- 
nal  abdominal  rings,  and  on  arriving  at   the 
rectus  muscle,  the  sheath  of  which  it  enters 
about  two  inches  above  the  pubis,  it  gives  off 
branches  from   either   side   to  the   abdominal 
muscles  and  peritoneum,  and  behind  the  linea 
alba,  establishes  a  very  free  inosculation  with 
its  fellow  of  the  opposite  side.  As  it  lies  behind 
the  inguinal  canal,  the  epigastric  artery  is  much 
nearer  to  the  internal  than  to  the  external  abdo- 
minal ring,  being   to  the   pubic   side   of  the 
former ;  here  the  vas  deferens,  as  it  passes  up 
from  the  pelvis  to  the  inguinal  canal,  hooks 
over  it,  and  receives  one  or  two  small  branches 
from  it.     In  passing  to  the  rectus  muscle,  this 
artery  lies  internal  to  the  linea  semilunaris.     It 
enters  the  sheath  of  the  rectus,  and  then  termi- 
nates by  anastomosing  with  the  internal  mam- 
mary.    The  course  of  this  artery  demands  par- 
ticular attention  from  the  surgical  anatomist  in 
reference  to  the  operations  for  inguinal  herniae, 
and  to  that  for  paracentesis  abdominis,  when 
the  abdomen  is  perforated  in  the  linea  semilu- 
naris.    The  trunk  of  the  artery  is  so  distant 
from  the  linea  alba  in  its  whole  course,  that  it 
is  free  from  danger  in  any  operation  performed 
in  that  line,  or  in  the  internal  half  of  the  rectus 
muscle,  and  its  security  in  such  operations  is 
increased  under  the  altered  state  of  parts  con- 

*  Diet,  de  Medecine,  art.  Abdomen. 


sequent  on  pregnancy,  ascites,  or  any  abdomi- 
nal tumour  pressing  similarly  on  the  abdominal 
wall.  In  these  cases  the  distance  of  the  artery 
from  the  linea  alba  is  increased  by  the  flattening 
of  the  rectus  muscle,  which  results  from  its 
compression.  —  (See  GROIN,  REGION  OF; 
HERNIA;  ILIAC  ARTERY.) 

The  circumflexa  ilii  artery  comes  likewise 
from  the  external  iliac,  near  to  the  origin  of  the 
epigastric;  it  passes  upwards  and  outwards  to- 
wards the  spine  of  the  ilium,  runs  along  the 
line  of  junction  of  the  fascia  iliaca  with  the 
fascia  transversalis,  covered  by  the  fascia,  and 
follows  the  circumference  of  theiliacus  internus 
muscle  to  end  in  anastomosing  with  the  iliolum- 
bar  artery.  From  that  part  of  the  artery  which 
intervenes  between  its  origin  and  the  spine  of 
the  ilium,  come  the  principal  branches  which 
it  supplies  to  the  abdominal  muscles. 

The  lateral  and  posterior  walls  of  the  abdo- 
men are  supplied  by  the  inferior  intercostals,  the 
lumbar,  the  iliolumbar,  the  circumflexa  ilii  arte- 
ries; the  superior  walls  by  the  phrenic  branches 
of  the  internal  mammary  and  by  those  of  the 
aorta.  It  is  in  cases  where  the  aorta  has  been 
obliterated  that  we  can  see  best  the  extent  of 
arterial  ramification  on  the  abdomen,  and  can 
appreciate  the  benefit  of  these  numerous  anas- 
tomoses, and  the  connexion  which  they  esta- 
blish between  the  upper  and  lower  portions  of 
the  aorta.* 

b.  The  veins. — The  veins  of  the  abdominal 
parietes  are  much  more  numerous  than  the 
arteries ;  each  artery  has  its  accompanying  vein 
or  veins,  but  those  which  are  especially  de- 
serving of  attention  are  the  tegumentary  veins 
which  accompany  the  superficial  epigastric 
artery,  and  those  which  ramify  along  with  the 
deep  epigastric  and  mammary.  The  subcuta- 
neous veins  demand  attention  in  consequence 
of  the  considerable  size  which  they  sometimes 
attain ;  this  enlargement  is  commonly  attendant 
on  ascites  and  on  pregnancy,  and  is  occasionally, 
to  a  remarkable  extent,  a  consequence  of  some 
irregularity,  obstructionf  or  retardation  of  the 
circulation,  in  the  deep-seated  veins  of  the  ab- 
domen, more  especially  the  inferior  vena  cava. 
The  veins  which  accompany  the  superficial 
epigastric  artery  empty  themselves  by  one  or 
more  trunks  into  the  vena  saphena  at  the  upper 
part  of  the  thigh. 

Two  veins  generally  accompany  the  deep 
epigastric  artery,  which  empty  themselves  into 
the  external  iliac  vein.  These  veins  are  equally 
subject  to  enlargement  with  the  preceding,  and 
from  similar  causes,  and  they  are  often  found 
in  a  varicose  condition  in  women  who  have 
borne  many  children. 

Some  curious  anomalies  have  been  observed 
in  the  venous  circulation  of  the  anterior  abdo- 
minal wall,  which,  as  being  calculated  to  in- 
terfere with  the  operator,  the  practitioner  would 

*  See  the  interesting  case  of  obliterated  aorta  re- 
corded by  Messrs.  Crampton  and  Goodissen.  Dub. 
Hosp.  Reports,  vol.  ii. 

t  As  in  the  case  of  obliteration  of  the  infeiior 
vena  cava  from  the  pressure  of  an  aneurismal 
tumour  observed  by  Reynaud.  Journal  Hebdom. 
de  Med.  vol.  ii.  p.  110. 


16 


ABDOMEN. 


do  well  to  note.  M.  Meniere*  has  described 
a  case  in  which  a  very  large  vein,  arising  from 
the  external  iliac,  passed  up  along  the  linea 
alba  to  the  umbilicus,  was  continued  along 
the  obliterated  umbilical  vein,  and  opened  into 
the  vena  portae.  In  another  case,  recorded  by 
Manec,  the  vein  originated  in  the  same  manner 
by  two  roots,  reached  the  umbilicus,  taking 
a  course  parallel  to  the  umbilical  artery,  formed 
an  arch  outside  the  navel,  and  having  re-entered 
the  abdomen,  opened  into  the  vena  portae.  In 
another  instance  which  occurred  to  Cruveilhier 
the  superficial  veins  in  the  hypogastric  region 
were  enormously  enlarged,  at  the  umbilicus 
they  ended  in  a  trunk  as  large  as  a  finger, 
which  communicated  with  the  vena  cava  as  it 
passed  under  the  liver.f  Berard  proposes  to 
explain,  by  the  supposition  of  the  existence 
of  such  anomalies  as  those  above  described, 
the  occurrence  of  fatal  hemorrhages  from 
wounds  inflicted  at  the  umbilicus,  which  have 
been  attributed  to  the  persistence  of  the  um- 
bilical vein.J 

c.  The  lymphatics. — Those  on  the  anterior 
wall    communicate    above    with    the   axillary 
glands,  and  below  with  those  of  the  groin  :  the 
deep-seated  lymphatics  of  the  posterior  wall 
communicate  with  the  glands  which  lie  along 
the  lateral  and  anterior  surfaces  of  the  lumbar 
spine. 

d.  The  nerves. — The  nerves  of  the  abdo- 
minal parietes  are  derived   from  the  inferior 
intercostals  and  from  branches  of  the  lumbar 
plexus.      The  seventh,   eighth,    ninth,   tenth, 
eleventh,  and  twelfth  intercostal  nerves  termi- 
nate in  supplying  the  transverse  and  oblique 
muscles  and  the  recti ;  the  twelfth  lies  in  front 
of  the  quadratus  lumborum  muscle,  and  gives 
several  filaments   to  that  muscle.     The  ilio- 
scrotal  and  inguino-cutaneous  nerves  are  the 
branches  of  the  lumbar  plexus  which  mainly 
supply   the  inferior  part  of  the   oblique  and 
transverse  muscles.     One  branch  of  the  genito- 
crural,  which  is  found  in  the  inguinal  canal, 
also  sends  some  twigs  to  these  muscles. 

The  posterior  wall  is  supplied  by  the  sub- 
divisions of  the  posterior  branches  of  the 
lumbar  nerves. 

Physiological  action  of  the  abdominal  parietes 
and  muscles. — We  have  already  alluded  to  the 
peculiarity  which  distinguishes  the  abdominal 
cavity  when  compared  with  the  other  great 
cavities,  namely,  that  its  walls  are  in  greatest 
part  composed  of  contractile  tissue.  At  first 
view  the  muscular  apparatus  of  the  abdomen 
would  appear  to  be  a  great  constrictor  muscle 
destined  principally  to  exert  its  influence  on 
the  cavity  and  its  contents ;  but  when  we  take 
into  account  the  attachments  of  those  muscles 


*  Archives  Gen.  de  Med.  t.  x.  p.  381.  The 
vascular  distribution  which  existed  in  this  subject 
presents,  as  Meniere  has  remarked,  a  striking  simi- 
larity to  that  which  is  naturally  found  in  the  Saurian, 
Ophidian,  and  Batrachian  reptiles,  viz.  a  division 
of  the  general  venous  system  which  communicates 
with  the  hepatic  vena  portae. 

t  Velpeau,  Anat.  Chir.  ed.  2.  vol.  ii.  p.  32,  and 
Mauec,  Dissertation  inaugurale.  Paris,  1826. 

$  Diet,  de  Med.  art.  Abdomen. 


to  the  ribs,  the  vertebrae,  and  the  pelvis,  it 
becomes  evident  that  they  must  likewise  be 
destined  to  act  upon  the  thoracic  and  pelvic 
cavities,  as  well  as  upon  the  vertebral  column. 
In  the  constitution  of  the  abdominal  parietes 
we  observe,  as  Berard*  remarks,  the  most 
happy  adaptation  of  structure  to  uses.  A 
completely  osseous  covering  would  have  greatly 
interfered  with  the  functions  of  the  abdominal 
organs,  which  are  liable  to  experience  changes 
both  extensive  and  often  very  rapid,  either  by 
reason  of  the  introduction  of  alimentary  matter, 
whether  solids  or  fluids,  or  by  the  disengage- 
ment of  gases  within  the  digestive  tube,  or  by 
the  progressive  development  of  the  impregnated 
uterus.  We  may  moreover  add  that  an  exact 
repetition  of  the  structure  of  the  walls  of  the 
thorax  would  not  have  been  well  adapted  to 
the  abdomen  for  the  same  reason,  namely,  the 
too  great  resistance  which  it  would  afford  to 
compression  from  within,  thereby  interfering 
with  the  distensibility  of  the  enclosed  viscera. 
The  resistance,  too,  which  a  wall  so  constituted 
would  afford  to  impulses  from  without  could 
not  have  been  so  easily  adapted  to  the  impetus 
of  the  forces  likely  to  act  upon  them  as  a 
purely  muscular  wall  whose  contractions  and 
the  intensity  of  them  are  obedient  to  the  will. 

The  consideration  of  the  action  and  uses  of 
the  abdominal  muscles  naturally  comes  under 
two  heads  :  —  1 .  their  action  upon  the  abdo- 
minal cavity  and  its  contents  ;  2.  their  influ- 
ence on  the  trunk  generally,  or  parts  of  it. 

It  is  the  muscles  that  enter  into  the  compo- 
sition of  the  anterior  and  lateral  walls  of  the 
abdomen  which  act  chiefly  on  the  cavity  and 
its  contained  viscera.  The  solidity  of  a  con- 
siderable portion  of  the  posterior  wall,  and 
the  great  strength  of  the  lumbar  muscles,  give  to 
that  wall  such  a  power  of  resistance  as  enables 
it  to  receive  the  compressed  viscera  without  at 
all  yielding.  A  reference  simply  to  the  attach- 
ments of  the  muscles  of  the  anterior  and  lateral 
walls  is  sufficient  to  shew  that  these  muscles 
when  contracted  must  diminish  the  capacity 
of  the  abdomen,  both  in  the  lateral  and  antero- 
posterior  directions ;  and  as  the  posterior  wall 
is  but  little  influenced,  the  viscera  will  be 
pushed  partly  upwards  against  the  diaphragm, 
and  partly  downwards  into  the  cavity  of  the 
pelvis,  where  their  further  descent  is  opposed 
by  the  levator  ani.  Hence  it  appears  that 
a  degree  of  antagonism  exists  between  the 
diaphragm  and  the  abdominal  muscles,  as 
well  as  also  between  those  muscles  and  the 
levator  ani.  It  is  extremely  difficult  to  maintain 
the  abdominal  muscles  and  the  diaphragm 
at  the  same  moment  in  a  state  of  contrac- 
tion; in  general  they  alternately  yield  the 
one  to  the  other :  and  when  it  does  happen 
that  they  are  simultaneously  contracted,  the 
abdominal  viscera  must  suffer  an  unusual  de- 
gree of  compression ;  and  it  is  not  improbable 
that  vomiting  is  sometimes  produced  by  such 
a  cause,  and  defecation,  no  doubt,  is  likewise 
aided  by  it.  The  danger  of  the  protrusion  of 
some  of  the  hollow  viscera  between  the  fibres 

*  Loc.  cit. 


ABDOMEN. 


17 


of   the   muscles   is   provided   against   by   the 
variation  of  direction  in  the  fibres  of  the  several 
layers;  thus  the  fibres  of  the  obliqui  are  in 
the  directions  of    two   intersecting  diagonals, 
and  those  of  the  transversalis  are  different  from 
both.     By  this  arrangement  a  sort  of  network 
is  formed,  with   meshes  so  small  as  to  render 
a  protrusion  perfectly  impossible  in  the  healthy 
condition  of  the  muscle.     In  the  compression 
of  the  viscera  the  abdominal  muscles  are  most 
completely   congeneres,    although    the    trans- 
versalis seems  to  be  the  best  adapted  to  this 
action,  and  probably,   for  that  reason,   forms 
the   layer  which   is   placed   nearest  the  peri- 
toneum.     The    recti    muscles    are    powerful 
auxiliaries  in  affording  a  fixed  point  of  attach- 
ment in  front  for  the  aponeuroses  of  the  broad 
muscles,    and   the    pyramidales    assist    in    a 
similar  manner  by  rendering  tense  the  linea 
alba.     Is  this  constant  action  of  the  abdominal 
parietes  on  the  viscera  necessary  or  favourable 
to  the  due  performance  of  the   functions  of 
those  organs,    or   to   the   continuance  of  the 
abdominal  circulation?     There  certainly  does 
not  appear  to  be  any  evidence  for  the  necessity 
of  them  for  this  purpose  :  that  they  are  favour- 
able to  it  may  be  inferred  from  the  fact  that 
they  do  bear  their  present  relation  to  them.     We 
know  from  numerous  experiments  on  animals, 
that  both   the   transmission  of   the   intestinal 
contents,  and  the  abdominal  circulation   may 
go  on  when  the  abdominal  muscles  have  been 
freely   opened   or  removed.      Hence  we  may 
answer  this   question   with   perfect  justice  in 
the  words  of  Bichat :  "  The  walls  of  the  ab- 
domen favour  these  functions  by  their  motions; 
but  these  motions  are  by  no  means  essential 
to  them." 

It  is  in  consequence  of  the  power  which  the 
abdominal  muscles  thus  appear  to  exert  in 
compressing  the  viscera,  that  some  physiolo- 
gists have  attributed  the  act  of  vomiting  to  their 
action  united  with  that  of  the  diaphragm;  and 
Magendie,  reviving  the  opinions  of  Bayle,  Chi- 
rac, and  Shwartz,*  went  so  far  as  to  deny  to 
the  muscular  coat  of  the  stomach  any  partici- 
pation in  this  act,  and  to  ascribe  it  wholly  to 
the  influence  of  the  abdominal  muscles.  But 
Beclard,  to  whom  the  question  was  referred  by 
the  Academy  of  Medicine  of  Paris,  proved 
satisfactorily  that  the  abdominal  muscles  are 
active  in  producing  vomiting  when  the  sto- 
mach is  distended  in  a  certain  degree,  and  that 
the  muscular  coat  of  the  stomach  is  also  active 
in  emptying  the  contents  of  that  viscus.  This 
conclusion  Haller  had  arrived  at  long  ago,  and 
clearly  expresses  it  in  the  following  passage : 
"  Evidentissimum  ergo  videtur,  vomitus  qui- 
dem  causam  esse  in  ventriculo  eumque  in  con- 
tractionem  niti  propriis  vinbus  atque  aliquando 
vomitum  perficere.  Plerumque  tamen  irrita- 
tionem  in  ventriculo  natam  et  sensum  summse 
anxietatis,  quse  vomitum  praecedunt,  facere  ut 
ad  levandam  aegrimoniam  vires  diaphragmatis 
2t  musculorum  abdominis  excitatae  atque  mo- 
lestiam  de  homine  amoliturae,  vomitum  per- 


*  Vide    Haller,    Elementa  Physiologiae,  t.   vi. 
sect.  iv.  §  xiv. 
VOL.  I. 


ficiant.  Unde  neque  a  sola  voluntate  in  pie- 
risque  certe  mortalibus  vomitus  cieri  potest 
ncque  a  .sola  absque  voluntate  natura — Quare 
recte  conjunctas  vires  ventriculi  et  or^anorum 
respirationis  Cl.  Viri  fecerunt.  Et  videtur  dia- 
phragmaet  abdomen  plusvirium  habere,quando 
ventriculus  aut  cibis  repletus  est,  aut  clausis 
ostiis  distentus :  tune  enim  magis  ad  perpen- 
diculum  proximum  ventriculum  comprimunt  et 
tota  contingunt."* 

If  it  be  admitted  that  the  abdominal  muscles 
are  active  in  producing  vomiting,  and  in  defe- 
cation and   micturition,  it  will  follow  likewise 
that  they  must   assist  in  parturition.     While 
these  pages  were  preparing  for  press,  the  fol- 
lowing passage  presented  itself  to  me,  in  an 
able  arid  interesting  review  of  M.  Velpeau's 
Treatise  on  Midwifery.     It  so  fully  illustrates 
the  part  which  the  abdominal  muscles  take  in 
promoting  parturition,  that  I  venture  to  tran- 
scribe   it,  "  It  is  certain,"  says  the  reviewer, 
"  that   a  woman  who   '  bears  down  '  as  it  is 
termed,  with  all  her  force,  who  makes  the  most 
of  her  pains,  however  feeble  they  may  be,  will 
thus  accelerate  her  delivery ;  and  that  another 
may  more  or  less  delay  delivery  by  voluntarily 
opposing  muscular  action  as  much  as  she  can. 
For  example; — a  woman  was  admitted  for  de- 
livery  at   M.  Baudelocque's   theatre  ;    labour 
went  on  regularly,  and  the  pupils  assembled. 
The  dilatation  of  the  cervix  now  slackened,  and 
no  progress  was  made  during  the  whole  night. 
The  ileves  were  fatigued  and  retired ;  the  pains 
immediately   returned,    and    dilatation    again 
went  on.     The  young  men  again  entered ;  the 
phenomena  of  labour  again  ceased.     Baude- 
locque,  suspecting  the  cause,  gave  a  hint  to  the 
students  to  retire,  but  to  be  at  hand  and  enter 
upon  a  given  signal.    The  patient  now  began 
to  *  bear  down,'  and  the  head  of  the  child  was 
quickly  at   the   vulva       The   spectators  were 
once  more  brought  to  the  scene  of  action,  and 
the  labour  was  speedily  terminated;  for  it  had 
now  advanced  too  far  to  be  suspended  by  any 
voluntary  effort  or  moral  alarm  of  the  woman. "f 
The  fixedness  of  the  inferior  attachment  of 
the  abdominal  muscles  to  the  pelvis,  and  the 
mobility  of  the  ribs,  to  which  they  are  attached 
superiorly,  evidently  indicate  that  these  muscles 
are  destined  to  act  upon  the  thoracic  cavity. 
The  transversalis  does  not,  from  the  direction  of 
its  fibres,  admit  of  this  action  to  any  extent; 
that  office,  therefore,  devolves  chiefly  on  the 
obliqui   and   recti.      When   these  last-named 
muscles  act  together,  they  must  compress  the 
inferior  opening  of  the  thorax,  draw  its  inferior 
margin  downwards  and  backwards,  and,  by  the 
compression  thus  exerted  on  the  abdominal  vis- 
cera, push  them  upwards  against  the  diaphragm, 
which  muscle  is  thus  made  to  ascend  into  the 
thorax,  and  that  cavity  is  thereby  diminished 
in  its  vertical  and  antero-posterior  diameters, 
and  also,  though  not  so  obviously,  in  its  trans- 
verse.    Hence  the  lungs  become  so  compressed 
as  to  be  adapted  to  the  altered  capacity  of  the 

*  Haller,  ubi  supra.  See,  also,  Richerand,  Physi- 
ologic par  Berard,  art.  Digestion,  $  xxiv. 
t  Medical  Quarterly  Review  for  April,  1835.  p.  100. 


Itf 


ABDOMEN. 


thorax,  and  thus  these  muscles  must  be  con- 
sidered as  very  important  agents  in  the  act  of 
expiration.  It  must  be  observed,  however, 
that  in  order  that  they  may  act  on  the  chest 
with  their  full  force,  it  is  necessary  that  that 
cavity  should  have  been  previously  in  a  state 
of  full  dilatation,  for  under  such  circumstances 
the  fibres  of  the  obliqui  and  recti  are  con- 
siderably stretched  and  their  levers  elongated.* 
It  is  in  the  excited  states  of  expiration,  cough- 
ing, sneezing,  &c.,  that  this  action  of  these 
muscles  is  most  obvious. 

But  it  is  in  the  motions  of  the  trunk  that 
the  abdominal   muscles   are  called  most  into 
play.     In  all  the  inflexions  of  the  trunk,  whe- 
ther the  body  be  horizontal   or  erect,   these 
muscles  are  main  agents.     When  the  body  is 
recumbent  on  a  horizontal  plane,  the  recti  are 
thrown  into  action  when  the  individual  attempts 
to  raise  up  the  thorax,  the  spine  being  thereby 
brought  into  the  state  of  flexion.  If  the  thorax  be 
fixed,  while  the  body  is  still  supine,  the  action 
of  the  recti  will  draw  the  pelvis  upwards  and 
forwards,  causing  slight  flexion  of  the  spine, 
and  slightly  approximating  the  upper  margin 
of  the  pelvis  to  the  lower  margin  of  the  thorax. 
Although  the  recti  muscles  are  the  principal 
agents  in  thus  flexing  the  spine,  the  obliqui  co- 
operate with  them  very  powerfully,  and    are 
especially  useful  in  maintaining  the  due  propor- 
tion between  the  middle  and  lateral  regions  of 
the  abdomen.     When  the  two  obliqui  of  the 
same  side  act  together,  the  direction  of  their 
force   is,  as  with  all  oblique  muscles  whose 
fibres  decussate,  in  the  diagonal  between  their 
fibres;  and,  therefore,  when  the  obliqui  of  op- 
posite sides  act  in  unison,  they  very  powerfully 
aid  the  recti  in  flexion  of  the  spine,  approx- 
imating the  thorax  and  pelvis  anteriorly.   When 
the  obliqui  of  one  side  act,  they  produce  a 
lateral  inflexion  of  the  trunk  to  that  side, — the 
middle  and  opposite  region  of  the  abdomen 
being  in  this  position  rendered  prominent  by 
the  viscera  pushed  over  from  the  side  of  the 
contracted  muscles.     In  what  have  been  called 
the  rotatory  motions  of  the  trunk,  the  obliqui 
muscles  of  the  same  side  antagonize  each  other; 
thus  in  that  movement  by  which  the  anterior 
surface  of  the  trunk  is  made  to  look  to  the  left 
side,  the  obliquus  externus  of  the  right  side  will 
co-operate  with  the  obliquus  internus  of  the 
left,  but  the  obliquus  internus  of  the  right  will 
antagonize   the  external   muscle  of  the  same 
side.     "  These  muscles,"  (obliqui  externi  et  in- 
terni,)   says   Dr.  Barclay,  "  from   occupying 
the  whole  of  the  lateral  aspects  extending  be- 
tween the  ilia  and  ribs,  and  from  acting  at  the 
greatest  lateral   distance   from   the    centre   of 
motion,  must  always  be  muscles  principally 
concerned  in  producing  inflexions  dextrad  and 
sinistrad  on  the  lumbar  vertebrae,  principal  di- 
rectors in  all  the  inflexions  sternad  and  dorsad ; 
and,  from  the  assistance  which  they  give  to  the 
recti,  principal  librators  also  of  the  trunk,  whe- 
ther we  be  sitting,  standing,  or  walking." 

The  reciprocal  action  of  the  recti  and  ob- 
liqui on  each  other  is  one  of  the  most  beauti- 

*   Barclay  on  Muscular  Motion,  p.  522. 


ful  parts  of  the  mechanism  of  the  abdominal 
muscles.     This  is  mainly  to  be  attributed  to 
the  close  connection  which  subsists  between 
these  muscles  in  consequence  of  the  formation 
of  the  sheaths  of  the  recti  by  their  aponeuroses, 
and  the  adhesion  of  the  anterior  wall  of  those 
sheaths  to  the  tendinous  intersections  of  the 
recti.     When  the  recti  contract,  the  antero-pos- 
terior  diameter  of  the  abdomen  is  diminished, 
and  consequently  the  viscera  are  pushed  to- 
wards the  sides ;  when,  on  the  other  hand,  the 
obliqui  contract,  they  diminish  the  transverse 
diameter  of  the  abdomen,  and  push  the  viscera 
forward  in  the  middle  line.     In  the  one  case, 
then,  it  will  be  evident  that  the  obliqui  act  as 
moderators  to  the  recti,  and  in  the  other  the 
resistance  of  the  recti  moderates  the  action  of 
obliqui, — the  former  muscles  being,  as  Cru- 
veilhier  remarks,  as  it  were,  two  active  pillars 
compressing  forcibly  the  viscera  against  the  an- 
terior surface  of  the  spine.     It  is  probably  to 
enable   the   recti  to  act   more  completely  as 
moderators  upon  the  several  segments  of  the 
obliqui  that  they  are  intersected  by  tendinous 
lines,  with  which  theaponeurosesof  those  muscles 
are  connected.    Another  use  has  been  assigned 
to  these  intersections  by  Berlin,  viz., — to  multi- 
ply the   points  of  attachment  of  the  obliqui 
muscles,  and  to  associate  them,  in  many  ac- 
tions, with  the  recti  muscles.   This  is  explained 
by  a  reference  to  the  action  of  the  recti  in  flex- 
ing the  pelvis:   were  these    muscles  uncon- 
nected with  the  obliqui,  they  would  act  only 
on  the  pelvis,  into  which  they  are  inserted ;  but 
in  consequence  of  the  insertion  of  the  internal 
oblique  into  the  intersections  of  the  recti,  and 
the  attachment  of  that  muscle  also  to  the  crista 
ilii,  the  force  of  contraction  of  the  recti  is  com- 
municated   not  only   to    the  pubis,  but  also 
through  the  fibres  of  the  obliquus  internus  to 
the  rest  of  the  pelvic  margin.* 

The  action  of  the  pyramidales  seems  to  be 
chiefly  on  the  linea  alba,  which  they  render, 
tense ;  thus  limiting  the  separation  of  the  recti, 
and  opposing  the  tendency  to  visceral  protru- 
sion. Fallopius  supposed  that  they  acted  on 
the  bladder,  especially  when  it  was  in  a  dis- 
tended state ;  and  Parsons  conjectured  that 
they  might  depress  the  suspensory  ligament  of 
the  bladder  (the  urachus),  and  thus  facilitate 
the  contraction  of  that  organ. 

The  other  muscles  which  are  from  situation 
abdominal  muscles  in  consequence  of  their 
connexion  with  the  posterior  wall  of  the  abdo- 
men, are  chiefly  agents  in  the  extension  of  the 
vertebral  column  :  in  their  contracted  state, 
however,  they  form  a  tense  and  resisting  sur- 
face, against  which  the  viscera  are  compressed 
by  the  contraction  of  the  anterior  muscles. 

II.  Of  the  Abdominal  Cavity. — The  annexed 
engraving  (Jig.  5.)  exhibits  a  view  of  the  abdo- 
minal cavity,  the  anterior  and  part  of  the  lateral 
walls  having  been  cut  away  and  the  viscera 
removed.  The  subject  is  so  bent  backwards 
as  to  render  the  bodies  of  the  vertebras  very 

*  Berard,   loc.    cit.,   et    Berlin,  sur  1'usage   de» 
enervations   des   muscles    droits   du   bas-ventre,  in 
.  de  1'Acad.  des  Sciences  de  Paris. 


ABDOMEN. 


(Fig.  5.) 

prominent  anteriorly,  and  the  continuity  of  the 
abdominal  and  pelvic  cavities  is  thus  clearly 
shewn.  It  is  useful  to  examine  the  relations 
of  the  axes  of  these  two  cavities  ;  that  of  the 
pelvis  passes  forwards  and  upwards  towards 
the  umbilicus,  while  the  axis  of  the  abdomen 
passes  from  above  downwards  and  forwards 
so  as  to  terminate  a  little  above  the  pubis, 
the  two  axes  accordingly  would  intersect  each 
other  a  little  below  the  umbilicus  at  an  obtuse 
angle.  This  angle  may  be  obliterated  by 
bringing  the  pelvis  very  much  forward  and 
producing  a  full  flexion  of  the  spine,  and  hence 
in  all  efforts  for  expulsion  that  attitude  is  almost 
instinctively  assumed  which  shall  identify  the 
axes  of  the  two  cavities,  and  thus  direct  the 
efforts  in  the  most  favourable  manner.  The 
ordinary  form  of  the  cavity  in  the  adult  male  is 
oval,  but  it  presents  some  slight  differences  in 
the  female  and  in  the  fetus ;  and  these  differ- 
ences are  dependent  on  the  great  or  incomplete 
development  of  the  pelvis.  In  the  female  the 
abdomen  is  generally  more  capacious  than  in 
the  male  ;  and  this  greater  size  is  more  remark- 
able at  the  inferior  part  of  it  in  the  hypogastric 
region.  In  fact  in  the  male  it  would  seem  that 
the  great  extremity  of  the  oval  is  toward  the 
thorax,  and  its  smaller  one  towards  the  pelvis ; 
but  in  the  female  it  is  just  the  reverse,  the 
larger  extremity  being  toward  the  pelvis.  It 
should  be  observed,  however,  that  the  modern 


fashion  of  tightly  compressing  the  lower  part  of 
the  thorax  has  a  material  effect  on  the  external 
characters  of  the  female  abdomen,  otherwise 
there  is  no  reason  that  the  superior  part  of  it 
should  be  proportionally  less  than  in  the  male. 
In  the  foetus  the  abdomen  is  proportionally  larger 
than  at  any  other  period  of  life  :  this  is  to  be 
attributed  to  the  imperfect  development  of  the 
pelvis,  and  likewise  to  the  great  size  which 
some  of  the  abdominal  viscera  possess  ;  and  as 
some  time  must  elapse  before  the  pelvis  reaches 
its  full  dimensions,  or  the  viscera  lose  their 
superfluous  parts,  the  abdomen  continues  of  this 
large  size  for  a  long  period  after  birth. 

The  subdivision  of  the  abdomen  into  regions 
is  especially  useful  in  reference  to  the  contents 
of  the  abdominal  cavity,  which  it  is  highly  de- 
sirable the  student  should  examine,  so  as  to  be 
able  to  assign  to  each  compartment  its  appro- 
priate contents.  The  abdominal  viscera  may 
be  subdivided  into  the  membranous  and  the 
parenchymatous  ;  the  former  being  such  as  the 
stomach  and  intestinal  canal,  the  latter,  such  as 
the  liver,  spleen,  pancreas,  &c.  The  viscera 
have  likewise  been  distinguished  in  reference 
to  their  position  with  respect  to  the  peritoneum, 
by  the  names  intra-peritoneal  and  extra-peri- 
toneal ;  but  it  is  sufficient  to  know  that  no 
serous  membrane  contains  any  organ  within  it 
(i.  e.  within  its  sac)  to  see  the  error  of  such  a 
distinction.  But  we  cannot  adopt  a  better  di- 
vision of  the  abdominal  viscera  than  that  which 
has  reference  to  the  functions  of  those  organs, 
and  which  Beclard  has  adopted  :  viz.  1  .  the 
organs  of  digestion  —  the  stomach,  the  intes- 
tinal canal,  the  liver  and  its  appendages,  the 
spleen,  and  the  pancreas  :  2.  the  urinary  organs  — 
the  kidneys  and  the  ureters,  to  which  may 
be  added  from  their  close  relation  to  the  kid- 
neys, the  suprarenal  capsules  :  3.  the  organs  of 
generation  in  the  male  —  the  vasa  deferentia,  and 
in  the  male  foetus  at  the  sixth  or  seventh  month 
of  intra-uterine  life,  the  testicles  ;  none  of 
the  organs  of  generation  can  strictly  be  said  to 
be  abdominal  organs  in  the  female.  In  both 
male  and  female  the  other  internal  generative 
organs  are  pelvic  viscera.  If  we  add  to  the 
above  enumeration  of  parts  the  abdominal  por- 
tion of  the  aorta,  its  primary  subdivision  into 
the  common  iliacs  ;  the  anterior  subdivision  of 
these  arteries  under  the  name  of  external  iliacs  ; 
the  branches  of  the  aorta  which  are  distributed 
to  the  viscera  as  well  as  to  the  walls  of  the 
abdomen  ;  the  common  and  external  iliac  veins; 
the  vena  cava  ascendens  ;  the  system  of  the  vena 
portae  ;  the  abdominal  portion  of  the  sympa- 
thetic system  of  nerves,  both  that  which  follows 
the  arterial  ramifications,  and  that  which  is  the 
continuation  of  the  chain  of  ganglia  that  lies 
along  the  spine,  the  termination  of  the  par 
vagum  ;  the  mesenteric  glands,  and  the  lacteals  ; 
the  lymphatics  and  their  ganglia  which  lie 
along  the  spine;  the  origin  of  the  thoracic  duct, 
a  portion  of  the  course  of  that  duct  ;—  these  wil  I 
complete  the  list  of  parts  contained  in  the  abdo- 
minal cavity. 

The  full  particulars  of  the  relative  positions  of 
the  contents  of  the  abdomen,  and  the  abnormal 

c  2 


20 


ABSORPTION. 


states  of  that  cavity,  both  congenital  and  mor- 
bid, including  also  the  abnormal  states  of  its 
parietes,  we  prefer  to  bring  together  in  a  sepa- 
rate article  under  the  head  CAVITY  ABDO- 
MINAL, to  which  we  beg  to  refer  the  reader. 
The  special  anatomy,  both  natural  and  ab- 
normal, of  the  several  abdominal  viscera  is 
distributed  among  the  articles  INTESTINAL 
CANAL,  KIDNEY,  LIVER,  PANCREAS,  SPLEEN, 
SUPRARENAL  CAPSULE. 

BIBLIOGRAPHY. — The  several  systematic  writers, 
as  Winslow,  Boyer,  Portal,  Bichat,  Meckel,  Cloquet, 
Marjolin,  Hildebrandt,  &c.  for  the  titles  of  whose 
respective  works  seethe  Bibliography  of  ANATOMY, 
(Introduction, ) —  Velpeau,  Anat.  Chirurgicale.  Paris, 
1833.  t.  ii.  Blandin,  Anat.  Topographique.  Cru- 
veilhier,  Dictionnaire  de  Med.  et  Chirurg.  art.  Abdo- 
men.  Beclard  et  Berard,  Diet,  de  Medecine. 
Ed.  2d.  art.  Abdomen.  Pierer  Anatomisch- 
Physiologisches  Realworterbuch.  herausgegeben 
von  J.  F.  Pierer.  Leipzig,  1816.  art.  Abdominal- 
muskeln.  Gerdy,  Anat.  des  formes  exterieures. 
Paris,  1829.  p.  122  and  199.  Cloquet,  Recherches 
Anat.  sur  les  Hernies  de  1'Abdomen,  or  the  trans- 
lation by  McWhinnie.  Lond.  1835.  Scarpa,  on 
Hernia,  by  Wishart.  Lawrence  on  ditto.  Todd,  on 
ditto.  Dub.  Hosp.  Reports,  vol.  i.  Flood's  plates  of 
Inguinal  and  Femoral  Hernia.  Lond.  1834.  Cam- 
per, Icones  Herniarum.  Guthrie,  on  Inguinal  and 
Femoral  Hernia.  A.  Cooper,  on  ditto,  and  on  the 
Testicle.  Munec,  Dissertation  Inaugurale  sur  1'Her- 
nie.1826.  Colles's  Surgical  Anatomy.  Dublin,  1811. 
Barclay  on  Muscular  Motion,  p.  337  et  sqq. 

( R.  B.  Todd.) 

ABSORPTION  in  physiology  (from  ab- 
sorbeo :  Lat.  absorptio,  Fr.  absorption,  Ger. 
die  einsaugung,  Ital.  assorbimento.}  The  term 
absorption  is  employed  in  physiology  to  de- 
signate a  vital  organic  function,  the  primary  or 
immediate  object  of  which  is  to  furnish  the 
system  with  a  due  supply  of  matter  for  its 
growth  and  subsistence.  It  is  proposed,  in  the 
following  article,  first,  to  give  an  account  of 
the  organs  by  which  the  function  is  performed ; 
this  will  lead  us,  2dly,  to  consider  the  question 
of  venous  absorption ;  in  the  third  place,  we 
shall  inquire  into  the  mode  in  which  the  ab- 
sorbents act ;  and,  lastly,  we  shall  offer  some 
remarks  upon  the  specific  uses  of  the  different 
parts  of  the  absorbent  system,  and  upon  the  re- 
lation which  it  bears  to  the  other  vital  functions. 

§.  1 .  Description  of  the  Absorbent  System. — 
We  propose,  in  the  first  instance,  to  restrict  the 
term  absorbent  system  to  those  organs,  which 
are  supposed  to  be  exclusively  appropriated  to 
the  function  of  absorption ;  these  may  be  in- 
cluded under  the  two  heads  of  vessels  and 
glands,  the  vessels  being  again  subdivided  into 
the  lacteals  and  the  lymphatics. 

Although  the  absorbents  are  distributed  to  al- 
most every  part  of  the  body,  and  perform  so  im- 
portant an  office  in  the  animal  economy,  they 
were  among  the  organs  which  were  the  latest 
in  being  discovered  by  anatomists.  There  are, 
indeed,  some  passages  in  the  writings  of  Galen,* 
which  would  lead  us  to  suppose  that  certain 

*  De  Anat.  Admin,  lib.  7,  sub  finem ;  De  usu 
partium,  lib.  4.  cap.  19  ;  An  sanguis  in  arteriis 
&c.  cap.  5. 


parts  of  the  absorbents  had  been  seen  by 
Erasistratus  and  Herophilus,  as  well  as  by 
himself;  but  it  appears  that  they  were,  all  of 
them,  unacquainted  with  the  relation  which 
these  vessels  bore  to  the  other  organs,  and  were 
entirely  ignorant  of  their  office  and  destination. 
These  scanty  observations  of  the  ancients  seem 
to  have  been  entirely  neglected,  or  even  for- 
gotten, until  the  study  of  anatomy  was  revived, 
together  with  that  of  the  other  medical  sciences, 
in  the  sixteenth  century.  In  the  course  of  the 
researches  which  were  then  made  into  the 
structure  of  the  animal  body,  various  parts  of 
the  absorbent  system  appear  to  have  been 
brought  into  view,  and  are  noticed,  among  other 
writers,  by  Fallopio,*  who  discovered  the  lym- 
phatics, connected  with  some  of  the  abdominal 
viscera,  and  by  Eustachio,f  who  detected  the 
thoracic  duct.  But  although  their  descriptions, 
especially  that  of  Eustachio,  are  sufficiently 
correct  to  enable  us  to  identify  them,  as  forming 
a  part  of  the  absorbent  vessels,  yet  they  were 
unacquainted  with  their  specific  nature  and 
office,  and  with  their  relation  to  the  sangui- 
ferous  system. 

It  is  generally  admitted  that  the  merit  of  the 
discovery  of  the  lacteals  is  due  to  Aselli ;  this 
discovery  he  made  in  the  year  1622.  While 
he  was  examining  the  abdominal  viscera  of 
a  dog,  he  observed  a  series  of  vessels  attached 
to  the  mesentery,  which  appeared  to  have  no 
direct  connexion  with  the  arteries  or  veins,  and 
which,  from  the  circumstance  of  their  con- 
taining a  white  opake  fluid,  he  denominated 
Lacteals.]: 

He  regarded  them  as  a  distinct  set  of  vessels, 
exercising  a  specific  function,  distinct  from 
that  of  the  sanguiferous  system,  and  he  as- 
certained that  they  took  their  origin  from  the 
surface  of  the  intestines,  and  proceeded  to- 
wards the  more  central  parts  of  the  body,  but 
it  was  not  until  the  year  1651,  that  their  ter- 
mination in  the  thoracic  duct  was  discovered  by 
Pecquet.  § 

The  discovery  of  the  other  species  of  ab- 
sorbent vessels,  styled,  from  the  appearance 

*  "  Observ.  de  Venis,"  lib.  3.,  in  Op.  p.  532; 
first  published  in  1561.  We  may  add  the  names  of 
Fabricio,  Piso,  and  Gassendi,  who  appear  to  have 
seen  certain  parts  of  the  lymphatics,  although  they 
were  not  aware  of  their  specific  nature.  See  Bar- 
tholin,  de  Lact.  Thor.  c.  2 ;  and  Mascagni,  Vas. 
Lymph.  Hist.  Proleg.  sub  init. 

t  De  Vena  sine  pari,  Antig.  13,  sub  finem,  in 
Opusc.  Anat.  ;  first  published  in  1564.  See  Haller, 
Bibl.  Anat.,  p.  224 ;  also  Douglas,  Bibliog.  Anat., 
p.  99. 

$  Dissertatio  de  Lactibus ;  first  published  in  1627. 
See  Bartholin,  de  Lact.  Thor.,  c.  4 ;  Sheldon  on 
the  Absorbent  Syst.,  p.  20,  1.  Aselli's  work  is  ac- 
companied by  plates  of  very  rude  execution,  but 
sufficiently  expressive  of  the  object. 

§  Exper.  nova  anat.  ;  first  published  in  1651  ; 
Bartholin,  c.  5.  In  1652,  Van  Home  published 
the  first  plate  of  the  thoracic  duct.  There  is  some 
reason  to  suppose  that  Vesling  had  an  imperfect  view 
of  it  previous  to  Pecquet ;  he  published  his  Syntagma 
Anat.  in  1647.  In  describing  the  pancreas  he  speaks 
of  the  venae  lacteae,  lately  discovered  by  Aselli, 
•which  convey  the  chyle  to  the  liver,  and  figures 
them  in  tab.  4.  fig.  3. 


ABSORPTION. 


-21 


of  the  fluid  which  they  contain,  the  lymphatics, 
was  posterior  to  that  of  the  lacteals.  The  trans- 
parency of  their  contents  rendered  them  less 
conspicuous  and  less  easy  of  detection,  so  that, 
although  certain  parts  of  them  appear  to  have 
been  seen  by  Fallopio,  and  afterwards  by 
Aselli  and  others,  yet  it  was  not  until  the  year 
1650,  that  they  were  distinctly  recognized,  and 
their  connexions  ascertained.  The  discovery 
of  the  lymphatic  system  was  the  subject  of  a 
warm  controversy  between  Bartholin  and  Rud- 
bek,  on  the  merits  of  which  we  are,  after  so 
long  an  interval,  scarcely  able  to  decide.  It 
appears,  however,  to  have  been  the  opinion  of 
Haller,  and  the  most  distinguished  anatomists 
of  the  last  century,  that  the  lymphatics  were 
detected,  in  the  first  instance,  by  Rudbek  ; 
that  Bartholin  had  some  intimation  of  the  dis- 
covery, that  he  then  took  up  the  subject,  and 
pursued  it  much  farther  than  it  had  been  done 
by  Rudbek.* 

There  is  a  third  individual,  on  whose  behalf 
a  claim  of  priority  has  been  made,  which  pos- 
sesses at  least  considerable  plausibility.  We 
are  informed  by  Glisson,  that  an  English  ana- 
tomist of  the  name  of  JolifTe  distinctly  re- 
cognized and  exhibited  the  lymphatics  of  many 
of  the  abdominal  viscera,  previously  to  the 
alledged  discovery  of  either  Rudbek  or  Bar- 
tholin.f  But  even  if  we  allow  Joliflfe  the  full 
merit  both  of  discovering  these  vessels,  and 
being  aware  of  their  specific  nature,  it  does  not 
appear  that  he  published  his  discovery,  so  that 
it  will  scarcely  affect  the  rival  claims  of  the 
former  anatomists.  The  discovery  of  the  ab- 
sorbent or  conglobate  glands,  as  they  have  been 
termed,  was  made,  for  the  most  part,  at  the 
same  time  with  that  of  the  vessels,  as  a  ne- 
cessary consequence  of  the  intimate  connexion 
which  subsists  between  them. 

After  the  existence  of  the  lacteals  had  been 
clearly  announced  by  Aselli,  and  of  the  lym- 
phatics by  Rudbek  and  Bartholin,  the  atten- 
tion of  anatomists  was  very  generally  directed 
to  these  organs,  and  discoveries  were  suc- 
cessively made,  by  various  individuals,  of  the 
presence  of  the  latter  in  almost  every  part  of 
the  body,  and  in  connexion  with  almost  every 
one  of  its  organs.  The  labours  of  William  and 
John  Hunter,  of  Monro  sec  ,  arid  of  Hewson, 
were  among  the  most  important  in  their  re- 
sults, while  we  are  indebted  to  Cruikshank, 
and  still  more  to  Mascagni,  for  their  minute 
descriptions  and  accurate  representations  of  the 
absorbent  system,  in  all  its  parts,  and  with  its 
various  relations  and  connexions.]: 

*  El.  Phys.,  ii.  3.  1;  BiV.l.  Anat.,  t.  i.  §.378 
and  415;  and  Not.  4.  ad  §.  121.  Boer.  Prsel. 
Bartholin's  statement  of  his  claim  is  contained  in 
his  "  Anat.  Reform."  p.  621,  2  ;  see  also  his  trea- 
tise, "  Vas.  Lymph.  Hist.  Nov."  and  Rudbek's 
*'  Nova  Exerc.  Anat."  For  the  historical  part  of  the 
subject  we  may  refer  to  Mascagni,  Prolegomena, 
and  to  Meckel,  Manuel  d'Anat.  par  Jourdan  et 
Breschet,  t.  i.  ch.  2.  p.  179  .  .  202. 

t  Anat.  Hepat.  c.  31.  See  Haller,  Bibl.  Anat., 
t.  i.  p.  452  ;  also  Mascagni,  Prolegomena. 

t  For  the  most  original  and  correct  desciiption  of 
the  lacteals,  the  reader  is  referred  to  Haller,  El. 
Phys.  xxv.  1.  4  .  .  8  j  Mascagni,  Vas.  Lymph.  Corp. 


With  respect  to  the  minute  anatomy  of  the 
lacteals,  we  are  informed  that  they  originate 
from  certain  small  projecting  bodies,  termed 
villi,  which  are  attached  to  the  interior  surface 
of  the  intestines,  styled  from  this  circumstance 
the  villous  coat.  These  villi  are  described  as 
consisting  of  a  number  of  capillary  tubes, 
which  terminate  with  open  mouths,  and  that 
by  the  union  of  these  tubes  the  branches  of 
the  lacteals  are  composed,  which  are  suffi- 
ciently large  to  be  visible  to  the  eye.  We  must 
remark,  however,  that  although  these  villi,  as 
constituting  the  mouths  of  the  lacteals,  have 
been  minutely  described,  and  even  figures 
given  of  the  appearance  which  they  exhibit  in 
the  microscope,  yet  that  considerable  doubt  is 
still  entertained  of  their  existence,  and  that  they 
are  even  entirely  discredited  by  some  anatomists 
of  the  first  eminence.*  Upon  the  whole  we 
may  conclude  that  the  opinion,  which  has  been 
generally  adopted,  respecting  the  capillary 
termination  of  the  lacteals,  is  somewhat  theo- 
retical, rather  derived  from  the  supposed  ne- 
cessity of  such  a  formation  to  cany  on  the 
functions  of  the  vessels,  than  from  any  actual 
observations  that  have  been  made  upon  them. 

When  the  lacteals  have  acquired  sufficient 
magnitude  to  become  visible  to  the  eye,  they 
are  seen  to  proceed  along  the  mesentery,  the 
small  vessels  running  together  to  form  large 
branches,  and  these  again  forming  others  that 
are  still  larger,  until  the  whole  of  them  unite 
into  a  few  main  trunks,  which  terminate  in  the 
receptacle  at  the  lower  extremity  of  the  thoracic 
duct.  During  their  progress,  the  small  vessels 

Hist.,  p.  1.  $.  7.  art.  8.  tab.  1.  fig.  7;  Sheldon,~on 
the  Absorb.  Syst.  ch.  2.  pi.  3,  4,  5 ;  Santorini, 
Tabulae,  No.  13.  fig.  3  ;  Magendie,  Physiol.  t.  ii. 
p.  158  .  .  0.  The  translation  of  Mascagni 's  work,  with 
copious  notes  by  Bellini,  may  be  advantageously 
consulted  ;  it  is  not  accompanied  by  plates.  For 
the  lymphatics  we  may  refer  to  Haller,  ii.  3.  2  ; 
Meckel,  Diss.  Epist.  de  Vasis  Lymphaticis  ;  Hew- 
son, Enq.,  ch.  3.  pi.  3,  6  ;  Mascagni,  ps.  1.  sect. 
7.  tab.  4  et  seq.  ;  Cruikshank,  on  the  Absorb.,  p. 
148  et  seq.  ;  Soemmering,  Corp.  Hum.  Fabr.  t.  v. 
p.  388  et  seq.  ;  many  of  Mascagni's  plates  are 
transferred  into  Cloquet's  valuable  "  Manuel." 
Art.  "  Inhalation,"  par  Rullier,  in  Diet,  des 
Sc.  Med.  t.  xxv.  3.  Art.  "  Lymphatique,"  par 
Chaussier  et  Adelon,  ibid,  t.  xxix.  p.  249,  260 ; 
Meckel,  Manuel,  sect.  6.  ch.  2;  Quain's  Elem.  of 
Anat.  p.  560  .  .  574.  In  Elliotson's  Physiol.  ch.  9. 
p.  140  . .  2,  we  have  a  "  short  account  of  the  first 
discovery  of  the  absorbent  system."  Scemmer- 
ing's  treatise,  De  Morbis  Vasorum  Absorb,  con- 
tains a  most  ample  and  learned  catalogue  of  the 
various  works  on  absorption,  from  the  earliest 
period  to  the  date  of  its  publication  in  1795. 

*  See  Lieberkuhn,  Diss.  de  Fabr.  Vill.  Intest. 
passim,  cum  tab.  1,  2;  Hewson's  Enq.,  c.  12, 
pt.  2  ;  Cruikshank's  letter  to  Clare,  p.  32  .  .  4  ;  Shel- 
don on  the  Absor.  Sys.,  p.  32 .  .  8,  tab.  1,  2 ;  Hedwig, 
Disq.  Ampull.  In  opposition  to  these  and  other 
authorities,  on  the  affirmative  side  of  the  question, 
we  have  the  strong  negative  evidence  of  Mascagni, 
whose  plates  do  not  sanction  the  description  of 
Lieberkuhn,  tab.  1.  fig.  1.  3 ;  and  tab.  3.  fig. 
1,2,3,  5;  and  the  decided  opinion  of  Magendie, 
Journ.  de  Physiol.  t.  i.  p.  3  et  alibi.  On  this  sub- 
ject see  the  remarks  of  Haller,  not.  9.  ad  §.  91. 
Boerhaave,  Prael.  et  not.  4.  ad  §.  103.  The  ob- 
servations of  Du  Vernoi,  Mem.  Petrop.  t.  i.  p.  262 
ec  seq.,  seem  scarcely  to  have  been  confirmed. 


22 


ABSORPTION. 


frequently  anastomose  with  each  other,  so  as, 
in  many  instances,  to  form  a  complete  network 
or  plexus,  in  which  respect  their  course  differs 
from  that  of  the  veins,  where  the  small  branches 
unite  to  form  the  larger  ones,  without  the  lateral 
communications. 

The  lacteals  are  furnished  with  numerous 
valves,  which  are  disposed  in  pairs,  and  have 
their  convex  surface  turned  towards  the  intes- 
tine,* so  that,  in  the  ord.nary  and  healthy  con- 
dition of  the  vessels,  their  contents  are  pre- 
vented from  retrograding,  and  necessarily  pro- 
ceed from  the  small  branches  to  the  larger 
trunks.  The  coats  of  the  lacteals  are  thin  and 
transparent,  and  hence  it  is  that  these  vessels, 
except  when  they  are  filled  with  chyle,  are  so 
difficult  of  detection.  They  seem,  however, 
notwithstanding  the  apparent  delicacy  of  their 
texture,  to  be  possessed  of  considerable 
strength,  and  to  bear  being  distended  far  be- 
yond their  ordinary  dimensions  without  being 
ruptured.  When  they  are  completely  filled 
with  chyle,  and  still  more,  when  they  are  for- 
cibly distended  by  injections,  the  number  of 
valves  which  they  possess  gives  them  a  jointed 
or  knotted  appearance,  and  it  seems  to  have 
been  this  circumstance,  together  with  the  white 
colour  of  their  contents,  which  first  attracted 
the  notice  of  anatomists,  and  led  to  their  dis- 
covery. With  respect  to  their  structure,  besides 
the  peritoneal  covering  which  they  possess  in 
common  with  all  the  abdominal  viscera,  they 
seem  to  be  composed  of  two  distinct  parts,  an 
internal  membrane,  which  by  its  duplicature 
forms  the  valves,  and  an  external  membrane, 
which  constitutes  the  main  substance  of  the 
vessel. 

To  these  two  obvious  component  parts  many 
authors  have  added  a  muscular  coat,  and  some 
anatomists  of  great  respectability  assert  that 
they  have  actually  detected  transverse  fibres,  in 
which  their  contractile  power  is  supposed  to 
reside.  Other  anatomists,  however,  of  equal 
authority,  deny  the  existence  of  this  muscular 
coat,  and,  it  must  be  acknowledged,  that  the 
weight  of  the  negative  evidence  seems  to  pre- 
ponderate. But  we  may  remark,  on  the  other 
hand,  that  although  these  transverse  fibres, 
constituting  the  muscular  coat,  in  consequence 
of  their  transparency,  or  from  some  other 
cause,  have  hitherto  eluded  our  observation, 
so  that  we  have  no  positive  proof  of  their 
existence,  the  lacteals  certainly  exhibit  what 
appears  to  be  very  decided  marks  of  contracti- 
lity, and  as  they  are  not  immediately  con- 
nected with  any  organ  equivalent  to  the  heart, 
there  seems  to  be  no  means,  except  their  own 
contractility,  by  which  their  contents  can  be 
propelled-!  See  CHYLIFEROUS  SYSTEM;  LAC- 


*  These  were  very  minutely  examined  by  Ruysch, 
Dilucid.  Valvul.,  op.  t.  i,  p.  1  .  .  13  ;  they  are  ac- 
curately described  by  Sheldon,  p.  28. 

t  Mascagni,  ps.  i.  sect.  4.  p,  26,  informs  us  that 
he  could  not  detect  the  fibres;  Cruikshank,  on  the 
contrary,  conceives  that  he  has  seen  them  in  the 
thoracic  duct,  p.  61  et  alibi ;  and  Sheldon  speaks 
of  the  muscular  coat  as  sufficiently  obvious,  p.  26. 
Meckel,  Manuel,  (.  i.  p.  185,  does  not  admit  their 
sxistence  ;  and  this  is  the  case  with  Chaussier  and 


The  anatomical  structure  of  the  lymphatics 
seems  to  be  essentially  similar  to  that  of  the 
lacteals ;  they  are  composed  of  a  firm  elastic 
membranous  substance,  capable  of  consider- 
able distention  without  being  ruptured,  and 
furnished  with  numerous  valves ;  like  the  lac- 
teals they  form  very  frequent  anastomoses. 
We  have  the  same  evidence  of  their  contracti- 
lity as  of  that  of  the  lacteals,  although  we  are 
perhaps  still  less  able  to  demonstrate  the  actual 
existence  of  their  muscular  fibres.  We  presume 
that  they  are  likewise  analogous  to  the  lacteals 
in  the  nature  of  their  office,  and  in  their  desti- 
nation, although  they  differ  from  them  with 
respect  to  their  situation,  or  the  parts  of  the 
body  to  which  they  are  attached  ;  the  lacteals 
being  confined  to  the  membranes  connected 
with  the  intestines,  while  the  lymphatics  are 
found  in  almost  every  part  of  the  body,  and 
connected  with  nearly  all  its  various  textures.* 
They  differ  also  in  the  nature  of  the  fluid 
which  they  contain,  for  while  that  of  the  lac- 
teals, as  has  been  stated  above,  is  white  and 
opaque,  the  fluid  found  in  the  lymphatics  is 
transparent  and  colourless,  so  as  to  resemble 
water,  from  which  they  have  derived  their  spe- 
cific denomination. 

It  is  very  difficult,  if  not  impossible,  to  trace 
the  actual  commencement  of  the  lymphatics ; 
but  partly  from  anatomical  researches,  and 
partly  from  physiological  considerations,  we 
are  led  to  conclude  that  they  originate  from 
the  various  surfaces  of  the  body,  of  all  de- 
scriptions, both  internal  and  external.  They 
resemble  the  lacteals,  in  passing  from  larger 
to  smaller  branches,  which,  after  numerous 
anastomoses,  unite  in  a  few  large  trunks,  the 
greatest  part  of  which  terminate  in  the  thoracic 
duct.  The  great  trunks  of  the  lymphatics  are, 
for  the  most  part,  arranged  into  two  distinct 
series,  one  considerably  more  superficial  than 
the  other;  it  is  observed  that  they  generally 
follow  the  course  of  the  great  veins,  but  it  may 
be  doubted  whether  any  direct  communication 

Adelon,  "  Lymphatique,"Dict.  des  Sc.  Med.  t.xxix. 
p.  256.  Breschet,  art.  "  Lymphatique  Systeme," 
Diet,  de  Med.  t.  xiii.  p.  389,  considers  it  doubtful. 
Some  curious  observations  were  made  by  Desge- 
nettes,  on  the  action  of  the  absorbents  after  the 
apparent  death  of  the  system,  Journ.  Med.  t.  Ixxxiv. 
p.  499  et  seq.  Similar  observations  were  after- 
wards made  by  Valentin,  t.  Ixxxvi.  p.  231,  et  seq. ; 
this  action  was  not,  however,  supposed  to  depend 
on  contractility.  Wrisberg  informs  us  that  he  has 
frequently  seen  spasmodic  contractions  in  the  large 
vessels  a'nd  in  the  thoracic  duct,  Observ.  Anat. 
Med.  de  Vas.  Abs.  Morb.  in  Comment.  Soc.  Reg. 
Gotting.  v.  ix.  §  19.  p.  149. 

*  For  the  extent  of  the  lymphatic  system,  see 
Haller,  El.  Phys.  ii.  3.  4,  and  the  later  account 
of  M.  Magendie,  Physiol.  t.  ii.  p.  174,  and  Jour, 
t.  i.  p.  3,  who  conceives  that  absorbent  vessels  have 
not  been  detected  in  the  brain,  the  spine,  and  the 
organs  of  sense.  Dr.  Alison  likewise  conceives  that 
they  have  not  been  detected  in  the  cranium  or  ner- 
vous system,  Outlines  of  Physiol.  p.  76.  Mas- 
cagni, however,  appears  to  have  detected  a  few 
small  lymphatics  in  the  brain,  tab.  27.  fig.  1. 
Monro  secundus  argues  in  favour  of  their  existence, 
but  it  does  not  appear  that  he  actually  detected 
them  in  any  part  of  the  nervous  system  ;  on  the 
Nervous  System,  ch.  v.  sect  1.  and  Three  Treatises, 
ch.  4,  5. 


ABSORPTION. 


23 


exists  between  them  during  their  course,  and 
we  are  not  aware  of  any  physiological  cause  of 
this  arrangement. 

With  respect  to  the  mouths  or  origin  of  the 
lymphatics  there  is  even  more  uncertainty  than 
with  respect  to  that  of  the  lacteals ;  no  anato- 
mical investigation  has  hitherto  been  able  to 
detect  them,  and  although  numerous  facts  of 
constant  occurrence  would  seem  to  prove  that 
their  capillary  extremities  are  distributed  over 
all  the  surfaces  of  the  body,  it  is  from  various 
pathological  observations  and  from  the  analogy 
of  the  lacteals  that  we  arrive  at  this  conclu- 
sion.* 

The  thoracic  duct  is  a  vessel  of  considerable 
size,  which  is  situated  near  the  spine,  and 
which  extends  from  about  the  middle  of  the 
dorsal  vertebrae  to  a  short  distance  above  the 
left  subclavian  vein ;  here  it  assumes  an  arched 
form,  and  is  bent  down  until  it  enters  the  vessel 
near  its  junction  with  the  jugular  vein  of  the 
same  side.f  The  duct,  in  its  passage  along 
the  spine,  is  deflected  in  various  ways,  and 
proceeds  in  a  somewhat  irregular  or  tortuous 
course.  For  the  most  part  it  consists  of  a 
single  trunk,  but  occasionally  there  are  two 
trunks,  either  of  the  same  or  of  different  sizes, 
and  we  have  not  unfrequently  partial  appen- 
dages, which  are  added  to  the  main  trunk  in 
different  parts  of  its  course.]:  Besides  what  is 
properly  considered  as  the  thoracic  duct,  in 
which  all  the  lacteals  and  the  greatest  part  of 
the  lymphatics  terminate,  a  portion  of  these 
latter,  especially  those  which  proceed  from  the 
upper  part  of  the  body  and  from  the  superior 
extremity  of  the  right  side,  are  generally  col- 
lected into  a  separate  trunk,  named  the  great 
right  lymphatic  vessel,  or  right  thoracic  duct, 
which  is  connected  with  the  right  subclaviau 
vein.§  These  irregularities  in  the  disposition 
and  form  of  the  thoracic  duct  may  be  consi- 
dered as  in  no  respect  affecting  its  physiological 
uses,  and  to  be  no  more  than  an  anatomical 
variation  of  structure,  probably  depending 

*  See  Magcndie,  Physiol.  t.  ii.  p.  175  Watson, 
however,  conceived  that  he  had  detected  their  open 
mouths  on  the  surface  of  the  bladder,  Phil.  Trans, 
for  1769,  pi.  16.  Monro,  in  speaking  of  the  lym- 
phatics of  fishes,  remarks  that  there  is  "  no  doubt 
that  they  begin  by  open  mouths,"  p.  30. 

t  For  descriptions  and  plates  of  the  thoracic  duct 
the  following  works  may  be  referred  to;  Haller, 
Prim.  Lin.  c.  xxv.  §  565;  Op.  Min.  t.  i.  p.  586 
et  seq.  tab.  11,  12  ;  and  El.  Phys.  xxv.  1.  10  .  .  3  : 
Albinus,  Tab.  Vas.  Chylif.  ;  Holius  and  Saltzmann, 
in  Haller,  Disp.  Anat.  t.  i.  ;  Cheselden,  Anat. 
pi.  26;  Portal,  Mem.  Acad.  pour  1770;  Sabatier, 
ibid,  pour  1786 ;  Haase,  De  Vas.  Cut.  et  Intest. 
Abs.  tab.  2.  and  tab.  3.  fig.  I  ;  Mascagni,  ps.  i. 
sect.  7.  art.  8.  tab.  13,  15,  19;  Sheldon,  pi.  5; 
Cruikshank,  p.  166. .  176  ;  Magendie,  Physiol.  t.  ii. 
p.  160;  Meckel,  Manuel,  §  1698. 

J  In  Mascagni,  tab.  15,  we  have  an  example  of 
this  irregularity. 

§  This  is  said  to  have  been  discovered  by  Stenon 
in  1664 ;  Meckel,  Manuel,  §  1703.  See  Haller, 
Prim.  Lin.  $  766  and  Hewson's  Enq.  pt.  2.  p.  61  .  .  3, 
pi.  4.  Cruikshank,  p.  176,  7,  conceives  that  Hew- 
son  was  the  first  who  described  the  lymphatics  of 
the  right  side  as  being  collected  into  one  trunk.  For 
the  figure  of  this  part,  see  Mascagni,  tab.  19.  nos. 
185,  187. 


upon  some  mechanical  cause.  It  is,  however, 
a  circumstance  of  considerable  importance  in 
respect  to  the  pathological  conclusions  that 
have  been  sometimes  drawn  from  the  obstruc- 
tions of  this  organ,  as  well  as  from  the  experi- 
ments that  have  been  performed  upon  it.*  The 
structure  and  properties  of  the  thoracic  duct 
appear  to  be  similar  to  those  of  the  large  trunks 
of  the  lacteals  and  lymphatics;  its  coats  are 
comparatively  thin  and  transparent,  yet  it  is 
possessed  of  considerable  strength,  and  is  ca- 
pable of  being  distended  much  beyond  its 
ordinary  bulk ;  it  is  furnished  with  numerous 
valves,  and  exhibits  a  great  degree  of  con- 
tractility. 

The  lymphatic  or  conglobate  glandsf  com- 
pose a  very  important  part  of  the  absorbent 
system,  if  we  may  judge  from  their  number 
and  their  general  diffusion  over  every  part  of 
the  body.  They  are  of  various  sizes,  and  are 
grouped  together  in  various  ways;  occasionally 
they  are  single,  but  more  frequently  connected 
together  in  masses  of  considerable  extent.  They 
are  found  in  almost  every  part  of  the  body, 
always  connected  with  the  lacteals  and  lympha- 
tics, and  it  is  asserted  that  each  one  of  these  ves- 
sels, in  some  part  of  its  course,  passes  through  or 
is  connected  with  one  or  more  of  these  glands.}; 
There  are  certain  parts  of  the  body  in  which 
they  are  more  numerous,  and  are  connected  in 
larger  masses ;  the  lacteals  are  furnished  with 
numerous  glands  in  their  passage  along  the 
mesentery,  while  the  glands  that  belong  to  the 
lymphatics  are  found  in  the  greatest  number 
and  largest  masses  in  the  groin,  the  axilla,  and 
the  neck.  It  is  necessary  to  remark  that  this 
account  of  the  distribution  of  the  lymphatic 
glands  applies  only  to  the  animals  which  belong 
to  the  class  of  the  mammalia;  in  birds  they  are 
much  more  rare,  and  still  more  so  in  fish,  while 
among  the  lower  animals,  where  we  have  suffi- 
cient evidence  of  the  existence  of  an  absorbent 
system,  the  glands  have  not  yet  been  satisfac- 
torily demonstrated  .§ 

With  respect  to  the  structure  of  these  glands, 
as  well  as  that  of  glands  of  other  descriptions, 
a  controversy  has  long  existed  among  anato- 
mists, whether  they  consist  of  a  series  of  cells 
or  follicles,  as  they  have  been  termed,  or  whe- 
ther they  are  composed  simply  of  a  congeries 
of  vessels.  The  question  may  be  regarded  as 
still  at  issue ;  but  it  may  be  remarked  that 
whereas  the  older  anatomists  generally  leaned 
to  the  opinion  of  the  follicular  structure  of  the 


*  See  on  this  subject  Sir  A.  Cooper,  in  Med. 
Rec.  and  Res.  p.  86  ct  seq.,  and  Magendie, 
Journ.  t.  i.  p.  21. 

t  Some  ot  the  late  French  physiologists  prefer 
the  term  lymphatic  ganglions,  upon  the  principle 
that  the  term  gland  more  properly  belongs  to  an 
organ  of  secretion. 

$  Mascagni,  ps.  1.  sect.  4.  p.  25 :  but  this  h<* 
been  doubted  by  some  anatomists;  see  Hewson,  pt.2. 
p.  44.  5. 

$  See  Fleming's  Zool.  t.  i.  p.  338  ;  Blumenbarh's 
Coimp.  Anat.  by  Lawrence,  ch.  xiii.  p.  256  ;  Diet, 
des  Sc.  Med.  art.  <«  Lymphatique,"  par  Chnussier 
et  Adelon,  p.  249;  Breschct,  art.  "  Lymph. 
Syst.,"  Diet,  de  Mod.  t.  xiii.  p.  397.  Hewson  in- 
forms us  that  birds  have  lymphatic  glands  in  the 


24 


ABSORPTION. 


glands,*  the  moderns  have  more  frequently 
adopted  the  hypothesis  of  their  vascular  texture, 
so  that  we  may  consider  this  doctrine  as  sup- 
ported by  the  most  recent  and  elaborate  re- 
searches, f  See  LYMPHATIC;  GLAND. 

§  2.  The  guest  ion  of  venous  absorption  con- 
sidered.— We  have  now  been  describing  those 
organs,  which  are  more  specifically  or  appro- 
priately termed  the  absorbent  system,  as  being 
those  parts  the  office  of  which  is  confined  to 
this  operation.  But  a  very  important  and  in- 
teresting question  must  now  be  discussed, 
whether  the  function  of  absorption  is  exclusive- 
ly performed  by  the  lacteals  and  the  lymphatics. 

The  ancient  anatomists  and  physiologists 
being  unacquainted  with  the  existence  of  the 
lacteals  and  the  lymphatics,  yet  observing  the 
evident  effect  of  the  operation  of  absorption, 
ascribed  these  effects  to  the  action  of  the  veins; 
and  among  the  moderns,  for  some  time  after  the 
discovery  of  what  were  more  appropriately 
termed  the  absorbent  vessels,  it  was  still  sup- 
posed that  the  veins  co-operated  with  them, 
and  in  some  cases  were  even  the  principal 
agents.  This  was  the  universal  doctrine  until 
the  middle  of  the  last  century,  and  was  one 
of  the  points  which  was  decidedly  maintained 
by  Haller  and  his  disciples.^ 

The  arguments  by  which  the  hypothesis  of 
venous  absorption  was  supported  may  be  re- 
duced to  two  classes,  partly  of  a  physiological 
and  pathological,  and  partly  of  an  anatomical 
nature;  the  first  consisting  of  the  results  of 
experiments  performed  for  the  express  purpose 
of  investigating  the  subject,  and  of  considera- 
tions derived  from  the  morbid  conditions  of 
the  system ;  the  second  depending  more  exclu- 
sively upon  anatomical  considerations.  The 

neck,  but  that  they  are  not  found  connected  with  the 
absorbents  of  the  abdomen,  and  that  they  are  en- 
tirely wanting  in  fish  and  in  the  amphibia  ;  Phil. 
Trans,  for  1768,  p.  217  et  seq.,  and  Enquiries, 
pt.  ii.  ch.  4,  5,  6.  We  have  the  same  statement 
made  by  Monro.  with  respect  to  fish,  p.  31.  An- 
tommarchi,  on  the  contrary,  asserts  that  birds,  fish, 
reptiles,  and  amphibia  have  "  pochissime  glan- 
dule ;"  Prod,  delle  grande  anat.  di  Mascagni,  p.  8^ 
but  the  statement  is  made  in  a  general  way,  and 
without  reference  to  any  particular  observations. 
It  would  appear  that  no  specific  apparatus  for  ab- 
sorption has  been  discovered  in  any  of  the  inverte- 
brated  animals. 

*  We  have  the  authority  of  Nuck,  in  favour  of 
the  cellular  structure,  Adenologia,  c.  ii.  p.  30  et 
seq.,  fig.  9  .  .  12  ;  also  of  Cruikshank,  c.  14  ;  and  of 
Abernethy,  Phil.  Trans,  for  1776,  p.  27  et  seq. 

t  See  Hewson,  v.  iii.  c.  2.  pi.  2;  Werner  and 
Feller,  Vas.  Lact.  and  Lymph.  Descript.  tab.  2; 
their  figures,  however,  appear  to  be  exaggerated  ; 
Beclard,  add.  a  Bichat,  p.  231  ;  Monro  tert.,  Elem. 
v.  i.  p.  558.  On  the  lymphatic  glands  generally 
see  Haller,  El.  Phys.  ii.  3.  16.  .27  ;  Beyer,  Anat. 
t.  iii.  p.  243  . .  257 ;  Mascagni,  ps.  i.  sect.  5.  p.  31 ; 
Rnliier,  ubi  supra,  p.  120  et  seq.  ;  Breschet,  ubi 
supra,  p.  394.  For  plates  of  the  glands,  see  Mas- 
ca<mi,  tab.  1 .  fig.  8 ...  12,  tab.  2.  fig.  4  .  .  8,  tab.  4. 
fig.  2.  tab.  8,  16,  26;  Cruikshank,  pi.  3;  Sheldon, 
tab.  3,  5. 

|  Boerhaave,  Praelect.  §  103.  and  $  247  ;  Haller, 
in  not,  1.  ad  §  106,  Boerhaave,  Praelect.,  and  not.  1. 
ad  §  245  ;  also  El.  Phys.  ii.  1.  28  ;  Monro  secun- 
dus,  De  Ven.  Lymph.,  p.  14  .  .  21  ;  Walter,  sur  la 
Resorption,  Nouv,  Mem.  Berlin,  pour  1786 .  .7,  §  15 
et  seq. ;  Magendie,  Physiol.  t.  ii.  p.  238. 


experiments  referred  to  consisted  in  passing 
injections  from  the  veins  to  the  absorbents,  or 
the  reverse,  thus  proving,  as  was  supposed, 
that  a  direct  connexion  subsisted  between  these 
vessels.  They  were  performed  by  the  most 
skilful  anatomists  of  the  age,  and  were  gene- 
rally acquiesced  in,  without  either  the  accuracy 
with  which  they  were  conducted,  or  that  of  the 
conclusions  deduced  from  them,  being  ever 
called  in  question.  Another  class  of  experi- 
ments consisted  in  passing  ligatures  round  the 
thoracic  duct,  so  as  to  render  it  impervious  to 
the  passage  of  the  chyle,  when  it  was  supposed 
that  under  these  circumstances  the  nutrition  of 
the  animal  was  not  interrupted,*  and  the  same 
conclusion  appeared  to  be  substantiated  by 
various  cases  of  natural  obstruction  of  the  duct, 
or  by  certain  malformations  of  the  part,  where 
it  was  either  defective,  or  did  not  convey  its 
contents,  in  the  ordinary  manner,  into  the 
veins.  The  other  set  of  arguments,  which  are 
more  purely  anatomical,  were  derived  from  the 
supposed  fact  that  various  parts  of  the  body, 
which  were  evidently  subject  to  the  operation 
of  absorption,  were  without  lymphatics,  and 
that  this  was  likewise  the  case  with  large  classes 
of  animals,  the  general  structure  of  which,  as 
far  as  regards  their  growth  and  nutrition,  was 
analogous  to  that  of  the  mammalia.  Admitting 
these  data,  it  seemed  to  be  a  necessary  conse- 
quence that  absorption  must  in  these  instances 
be  performed  by  the  veins,  and  hence  it  was 
inferred  that  in  all  classes  of  animals,  and  in  all 
parts  of  the  body,  the  veins  co-operated  with 
the  lacteals  and  the  lymphatics  in  the  function 
of  absorption. 

The  doctrine  of  venous  absorption  was  first 
formally  called  in  question,  nearly  at  the  same 
time,f  by  Wm.  Hunter  and  by  Monro  se- 
cundus,J  who,  as  it  would  appear,  to  a  certain 
extent,  entered  upon  the  investigation  inde- 
pendently of  each  other.  The  priority  of  dis- 
covery in  this,  as  in  so  many  points  connected 
with  anatomy,  was  for  a  long  time  the  subject 
of  warm  controversy.  We  may  remark  con- 
cerning this  question,  that  if  the  judgment  of 
Ihe  present  age  should  incline  to  ascribe  to 
Hunter  the  original  conception  of  the  hypo- 
thesis, it  is  also  disposed  to  allow  to  Monro  the 
merit  of  establishing  his  opinion  by  a  skilful  and 
laborious  process  of  experiment  and  observation. 

The  method  which  these  illustrious  rivals 
adopted  was,  first,  to  repeat  the  experiments 
of  their  predecessors,  when,  by  noticing  with 
scrupulous  accuracy  all  the  circumstances  con- 
nected with  them,  they  were  able  to  demon- 
strate, or  at  least  to  render  it  highly  probable, 
that  in  all  those  cases  where  injections  had 
passed  between  the  absorbents  and  the  veins, 
either  rupture  or  extravasation  had  taken  place, 
and  that,  when  this  was  carefully  guarded 

*  Some  experiments  of  this  kind  are  referred  to 
by  M.  Majendie,  as  having  been  performed  by  M. 
Dupuytren,  Physiol.  t.  ii.  p.  167.  See  also  Ri- 
cherand,  Elemens  de  Physiologie  par  Berard. 

t  Medical  Comment.,  passim  ;  Cruikshank,  In- 
trod.;  Walter,  §  10  et  seq. 

J  Dissert,  de  Sem.  rt  Test,  in  Smellie,  Thes. 
t.  ii.  and  De  Ven.  Lymph.  Valv. 


ABSORPTION. 


25 


against,  the  supposed  connexion  between  the 
two  sets  of  vessels  could  not  be  demonstrated.* 
In  those  experiments,  where  the  thoracic  duct 
had  been  artificially  obstructed,  or  in  the  cases 
where  the  same  thing  had  occurred  as  the 
result  of  disease  or  malformation,  they  were 
enabled  to  detect  some  supplementary  vessels 
or  some  imlirret  channel,  by  means  of  which 
the  chyle  had  been  conveyed  to  the  veins. 

With  respect  to  the  parts  of  the  body,  or 
to  the  animals  of  an  inferior  order,  which 
were  supposed  not  to  be  furnished  with  ab- 
sorbent vessels,  by  prosecuting  their  examina- 
tion with  more  care  they  gradually  detected 
the  existence  of  these  vessels  in  many  cases 
where  they  had  not  been  previously  known  to 
exist;  and  they  were  discovered  in  so  many 
new  situations  that  it  became  a  fair  inference 
that  every  part  of  the  body,  and  every  animal 
whose  structure  is  generally  analogous  to  that  of 
the  mammalia,  is  provided  with  an  appropriate 
apparatus  of  absorption,  although,  from  the 
texture  or  the  peculiar  nature  of  the  vessels, 
it  may  be  very  difficult  actually  to  demonstrate 
their  existence.  In  this  train  of 'investigation 
the  labours  of  William  Hunter  and  Monro 
were  ab!y  seconded  by  various  anatomists,  both 
in  this  country  and  on  the  continent,  among 
whom  we  may  select  the  distinguished  names 
of  John  Hunter,  Hewson,f  Cruikshank,  and 
Mascagni. 

*  We  must,  however,  bear  in  mind  that  we  have 
the  high  authority  of  Meckel  in  favour  of  the  com- 
munication between  the  lymphatics  and  the  veins  ; 
"  Sur  Resorption,"  "Nouv.  Mem.  Acad.  Berl.  ann. 
1770,  p.  19  et  seq. 

The  researches  of  some  of  the  most  accurate 
among  the  anatomists  of  the  present  day  seem  also 
to  show  that  occasional  communications  exist  be- 
tween some  of  the  lymphatics  and  the  contiguous 
veins;  but  this  is  a  different  kind  of  relation  from  that 
\vhich  was  contemplated  by  the  older  anatomists 
between  the  sanguiterous  and  the  absorbent  systems. 
This  point  is  fully  discussed  by  Fohmann,  in  his 
late  work,  '•  Sur  le  commun.  des  vaiss.  lymph, 
avec  les  veins,"  where  we  have  an  account  of  his 
own  observations,  as  well  as  those  of  preceding 
anatomists  ;  he  conceives  that  the  observations  of 
Lippi,  of  which  an  account  is  given  in  his  "  Illus- 
trazioni  fisiol.",  are  not  correct :  see  also  the 
remarks  of  Antommarchi,  Ann.  Sc.  Nat.  t.  xviii. 
p.  108,  9.  The  observations  of  Fohmann  have 
been  confirmed  by  Lauth,  in  his  "  Essai  sur  les 
Vaisseaux  Lymph."  We  may  here  refer  to  the 
observations  of  Bleuland,  which  were  made  fifty 
years  ago,  on  what  he  styles  the  arteriol;e  lym- 
phaticae,  by  which  a  communication  was  supposed 
to  be  maintained  between  the  sanguiferous  and 
absorbent  systems;  see  his  "  Experim.  Anat." 
Panizza  of  Pavia  also  opposes  the  doctrine  of 
Lippi  ;  Ossorvazioni,  c.  3  and  5.  Mr.  Abernethy, 
in  examining  the  vascular  system  of  the  whale, 
discovered  certain  communications  between  the 
sanguiferous  and  the  lymphatic  vessels ;  but  the 
nature  of  the  connexion  is  perhaps  a  little  doubtful  ; 
Phil.  Trans,  for  1796,  p.  27  et  seq.  For  further 
information  on  this  subject,  see  a  lecture  on  the 
lymphatic  system  lately  published  by  Dr.  Graves. 
Mr.  Kiernan,  in  his  elaborate  researches  into  the 
anatomy  of  the  liver,  gives  it  as  his  opinion  that 
the  doctrine  of  Lippi  has  been  "  satisfactorily  con- 
futed "  by  Panizza  ;  Ph.  Tr.  1833,  p.  729.  See 
Elliotson's  Physiol.  p.  128,9  ;  s.  1.  also  a  paper  in 
Ann.  Sc.  Nat.  t.  21.  p.  252  et  seq. 

t  Phil.  Trans,  for  1768  and  1769;  in  these   vo- 


The  experiments  of  Hunter  may  deserve  to 
be  particularly  noticed,  because  they  consisted 
not  merely  in  repeating  and  correcting  those 
of  preceding  anatomists ;  but,  in  addition  to 
these,  he  entered  upon  a  series  of  original 
researches,  which  are  highly  characteristic  of 
that  ingenuity  and  acuteness  for  which  he  was 
so  eminently  distinguished.  The  experiments 
essentially  consisted  in  filling  portions  of  the 
small  intestines  with  a  fluid,  the  sensible  pro- 
perties of  which  might  be  easily  recognized,  and 
retaining  it  there  so  as  to  allow  of  its  entering 
into  the  veins  of  the  mesentery,  were  they 
capable  of  absorbing  it ;  the  result,  however, 
is  stated  to  have  been  that  in  no  instance  could 
the  fluid  be  detected  in  these  veins.  These 
experiments  appeared  to  have  been  so  carefully 
conducted,  and  so  frequently  repeated,  as  to 
have  impressed  the  minds  of  anatomists  and 
physiologists  with  a  conviction  that  the  lacteals 
were  the  only  vessels  which  are  concerned  in 
the  absorption  of  the  chyle ;  and  although  it 
was  not  possible  to  perform  analogous  experi- 
ments on  the  lymphatics,  yet  it  seemed  a 
natural  inference,  that  we  might  extend  to  them 
the  conclusion  which  had  been  established  with 
respect  to  the  lacteals.* 

In  proof  of  lymphatic  absorption  various 
facts  were  brought  forward,  which  seemed 
clearly  to  show  that  when  extraneous  or  noxious 
substances  were  introduced  into  the  system,  it 
was  done  by  the  medium  of  the  lymphatic  vessels 
rather  than  of  the  veins;  and  it  was  thence 
argued  that,  as  these  vessels  perform  the  func- 
tion of  absorption  under  certain  circumstances, 
and  that  we  are  not  acquainted  with  any  other 
office  which  they  serve  in  the  system,  we  may 
conclude  that  they  are  the  sole  agents  in  the 
action  of  absorption.  Although  the  argument, 
as  applied  to  the  lymphatics,  was  far  less 
direct  and  conclusive  than  to  the  lacteals,  yet 
the  analogy  between  the  two  organs  appeared 
so  strong,  and  so  many  concurring  circum- 
stances appeared  to  favour  the  doctrine,  that 
it  was  very  generally  received,  and  may  be 
considered  as  having  been  the  established 
opinion  at  the  conclusion  of  the  last  century  .f 
This  unanimity  of  opinion  was,  however,  of 
very  short  duration;  for  anatomists  had  scarcely 
ceased  to  contend  for  the  honour  of  the  dis- 
covery of  the  exclusive  action  of  the  lacteals 
and  the  lymphatics  in  the  function  of  absorp- 
tion, when  the  doctrine  itself  was  impugned 
by  physiologists  of  the  first  eminence,  who 
supported  their  views  by  a  powerful  train  of 
arguments,  enforced  by  numerous  experiments, 

lumes  are  contained  his  account  of  the  lymphatics 
of  birds  and  fishes. 

*  Med.  Comment,  c.  5  p.  42  .  .  8  ;  Cruikshank, 
c.  5.  p.  21. 

t  See  the  judicious  summary  of  opinions  in 
Mascagni,  ps.  i.  sect.  2,  3  :  and  in  Rullier,  ubi 
supra,  p.  136  et  seq.  The  doctrine  of  venous  ab- 
sorption was,  however,  still  maintained  by  many 
intelligent  anatomists,  especially  by  the  high  au- 
thority of  Meckel,  De  Fin.  Ven.  et  Vas.  Lymph. 
1772 ;  and  of  Walter,  Sur  la  Resorption,  ubi 
supra.  See  particularly  his  general  conclusion, 
§  92  :  he  conceives  that  the  veins  are  the  only 
agents  in  the  absorption  which  is  carried  on  ut  the 
surface  and  from  the  cavities  of  the  body. 


26 


ABSORPTION. 


and  by  various  pathological  considerations. 
Of  these  authors,  one  of  the  first,  both  in 
point  of  time  and  of  ability,  is  M.  Magendie, 
whose  opinions  on  this  subject,  connected  as 
as  they  are  with  some  of  those  of  his  most 
distinguished  countrymen,  have  been  brought 
forward  in  a  form  which  entitles  them  to  the 
fullest  and  most  respectful  attention. 

Of  the  two  sets  of  observations  by  which 
Hunter  and  Monro  attempted  to  establish  their 
hypothesis  respecting  lymphatic  absorption, 
those  derived  from  the  analogy  of  the  lacteals 
may  still  be  considered  as  maintaining  their 
ground ;  while  the  conclusion  which  they  de- 
duced from  their  experiments  has  been  called 
in  question,  partly  because  it  was  thought  not 
to  be  the  legitimate  inference  from  the  experi- 
ments, and  partly  in  consequence  of  the  ex- 
periments themselves  having  been  conceived 
to  be  imperfect  or  incorrect.  It  is  principally 
upon  the  latter  ground  that  the  force  of  the 
objections  has  been  rested ;  and  it  has  been, 
first,  by  repeating  the  experiments  of  Hunter, 
and  afterwards  by  varying  them  in  different 
ways,  that  their  insufficency  has  been  attempted 
to  be  proved.  It  has  been  stated  above  that 
the  main  support  of  the  doctrine  of  the  ex- 
clusive action  of  the  lacteals  and  the  lymphatics 
was  derived  from  those  experiments  of  Hunter, 
in  which  it  appeared  that,  when  the  circum- 
stances were  the  most  favourable  for  the  re- 
ception of  substances  into  the  veins  of  the 
mesentery,  they  could  not  be  proved  to  have 
entered  these  vessels ;  and  hence  it  was  con- 
cluded that  the  veins  did  not,  under  any  cir- 
cumstances, possess  the  power  of  absorption. 

We  are  informed,  however,  by  M.  Magendie 
that  experiments  have  been  performed  by  him- 
self and  by  M.  Flandrin,  which  afforded  directly 
contrary  results,  and  that  these  experiments 
were  so  frequently  repeated,  and  varied  in 
such  a  manner,  as  to  leave  no  doubt  of  their 
accuracy.*  We  have  here  the  opposing  testi- 
mony of  individuals,  both  of  them  of  the 
highest  authority  in  science,  and  eminent  for 
their  skill  in  experimental  research.  From 
personal  considerations  it  might  be  difficult, 
if  not  impossible,  to  decide  between  them  ; 
but  when  we  take  into  account  the  circum- 
stance that  the  experiments  of  MM.  Magendie 
and  Flandrin  were  executed  subsequently  to 
those  of  Hunter,  and  with  the  benefit  of  his 
experience  and  that  of  the  improved  state  of 
the  science  during  the  last  half  century  ;  when, 
moreover,  we  are  informed  that  the  experiments 
of  the  French  physiologists  were  more  nu- 
merous than  those  to  which  they  were  opposed, 
and  that  their  results  were  uniform  and  un- 
equivocal, we  can  scarcely  refuse  our  assent 
to  the  conclusion,  that  the  experiments  of  John 
Hunter  do  not  afford  a  sufficient  foundation 
for  the  doctrine  of  the  non-absorption  of  the 
veins. 

But  the  French  physiologists  have  not  sa- 
tisfied themselves  with  repeating  the  experi- 
ments of  Hunter;  they  have  extended  them 

*  Physiol.  t.  ii.  p.  181  et  seq.  ;  Journ.  Med. 
t.  Ixxxv.  p.  372  et  seq.,  and  t.  Ixxxvii.  p.  221. 
et  seq.,  and  t.  ex.  p.  73  et  seq. 


in  various  ways,  and  have  obtained  results 
supposed  to  be  still  more  decisive  in  favour 
of  venous  absorption.  Among  the  most  im- 
portant, or  at  least  the  most  curious  of  these, 
is  an  experiment  which  was  performed  by 
M.  Magendie,  in  conjunction  with  M.  Delille, 
and  which  was  conceived  by  these  physiolo- 
gists to  afford  the  most  unequivocal  proof  of 
their  hypothesis.  It  consisted  in  dividing  all 
the  parts  of  one  of  the  posterior  extremities 
of  a  living  animal  except  the  artery  and  the 
vein,  and  in  applying  to  the  foot  a  poisonous 
substance ;  when,  in  the  short  space  of  a  few 
minutes,  the  effects  of  the  poison  on  the  func- 
tions of  the  animal  were  most  distinctly  ap- 
parent.* It  was  argued  that  in  this  case  there 
was  no  mode  of  communication  by  which  the 
poison  could  be  conveyed  from  the  extremity 
to  the  centre  of  the  system  except  the  vein, 
and  that,  therefore,  the  vein  must  have  acted 
as  the  absorbing  vessel.  The  experiment  was 
rendered  more  striking,  and,  as  was  conceived, 
more  conclusive,  by  dividing  the  bloodvessels 
themselves  and  introducing  metallic  tubes 
between  the  divided  ends,  through  which  alone 
the  two  currents  of  the  arterial  and  venous 
blood  respectively  could  pass  in  forming  the 
communication  between  the  extremity  and  the 
trunk  of  the  animal,  yet,  under  these  appa- 
rently unfavourable  circumstances,  the  delete- 
rious effects  were  manifested  on  the  system 
as  in  the  former  case.f  Experiments  of  this 
description  appear  to  have  been  sufficiently 
multiplied  to  establish  the  fact,  that  the  poison 
in  these  cases  passed  along  the  vein,  and  was 
conveyed  in  the  general  mass  of  the  blood. 

The  result  of  these  experiments  is  no  doubt 
very  remarkable,  and  what  would  scarcely 
have  been  anticipated;  yet  we  may  remark, 
that  there  is  one  circumstance  connected  with 
them,  which,  in  a  great  measure,  invalidates  the 
conclusion  that  has  been  supposed  to  follow  so 
necessarily  from  them.  It  may  be  inferred 
from  the  expression  made  use  of,  that  the 
poison  employed,  which  was  the  extract  of 
the  upas  tree,  was  inserted  by  a  puncture  or 
incision  into  the  foot  of  the  animal,  and  would, 
therefore,  in  the  first  instance,  be  mixed  with 
the  blood  ;  so  that  the  only  deduction  which  we 
are  warranted  to  draw  from  the  experiment  is, 
that  the  venous  blood,  being  infected  with  the 
poison,  had  the  power  of  communicating  the 
infection  to  the  system  at  large.J  On  this 
view  of  the  subject  we  should  not  regard  the 
above  as  a  case  of  absorption,  but  merely  as 
an  instance  of  the  power  of  extraneous  sub- 
stances, under  certain  circumstances,  of  uniting 
with  the  venous  blood  and  retaining  their 
specific  properties. 

In  connexion  with  these  experiments  of 
M.  Magendie  and  his  associates,  we  have 
another  series  which  were  performed  by  MM. 
Tiedemanri  and  Gmelin,  and  which  bear  di- 
rectly upon  the  question  of  venous  absorption. 
Their  object  was  to  ascertain  whether  there 

*  Magendie,  Journ.   t.  i.  p.  25  .  .  7. 
t  Journ.  t.  i.  p.  23  et    seq.  ;  Elom.  t.  ii.  p.  183  ,  .  5. 
J  See  llullier,  ubi  supra,  p.  150 .  .  2  :  and  Adelon, 
"  Absorption,"  Diet,  de  Med.  t.  i.   p.  148. 


ABSORPTION. 


27 


was  any  direct  communication  between  the 
organs  of  digestion  and  the  bloodvessels  except 
by  means  of  the  lacteals.  For  this  purpose 
they  mixed  with  the  food  of  an  animal  various 
substances,  which  by  their  colour,  odour,  or 
other  sensible  and  physical  properties,  might 
be  easily  detected  in  the  fluids  of  the  body. 
After  some  time  the  animal  was  examined,  and 
the  result  was  that  unequivocal  traces  of  the 
substances  were  not  unfrequeritly  detected  in 
the  venous  blood  and  in  the  urine,  while  it 
was  only  in  a  very  few  instances  that  any  in- 
dication of  them  could  be  discovered  in  the 
chyle.  The  colouring  matters  employed  were 
various  vegetable  substances,  such  as  gamboge, 
madder,  and  rhubarb  ;  the  odorous  substances 
were  camphor,  musk,  assafoetida,  &c. ;  while, 
in  other  cases,  various  saline  bodies,  such  as 
muriate  of  barytes,  acetate  of  lead  and  of 
mercury,  and  some  of  the  prussiates,  which 
might  be  easily  detected  by  chemical  tests, 
were  mixed  with  the  food.  The  colouring 
matters,  for  the  most  part,  were  carried  out 
of  the  system  without  being  received  either 
into  the  veins  or  the  lacteals;  the  odorous 
substances  were  generally  detected  in  the 
venous  blood  and  in  the  urine,  but  not  in 
the  chyle,  while  of  the  saline  substances  many 
were  found  in  the  blood  and  in  the  urine,  and 
a  very  few  only  in  the  chyle.* 

The  conclusion,  which  we  are  disposed  to 
regard  as  the  fair  inference,  from  the  facts  and 
arguments  that  have  been  adduced  on  the 
subject  of  venous  absorption,  is  that,  although 
there  are  strong  analogies  and  various  patho- 
logical considerations  which  would  induce  us 
to  confine  the  function  of  absorption  to  the 
lacteals  and  the  lymphatics,  yet  that  the  result 
of  the  experiments,  although  not  uniform,  is 
upon  the  whole  in  favour  of  venous  absorption. 
It  only  remains  for  us  to  inquire  how  far  the 
state  and  actions  of  the  parts  on  which  the 
experiments  were  made,  were  so  far  neces- 
sarily deranged  by  the  process  to  which 
they  were  subjected  as  to  render  the  results 
inapplicable  to  the  natural  condition  of  these 
organs.  Now  this  certainly  appears  to  be  the 
case  in  the  experiments  of  MM.  Magendie 
and  Delille,  where  the  poisonous  substance 
was  introduced  into  the  blood ;  and  the  same 
remark  may  probably  be  applied  to  a  number 
of  pathological  occurrences  that  have  been 
supposed  to 'afford  a  proof  of  venous  absorp- 
tion, such,  for  example,  as  the  case  of  ulcerated 
surfaces,  where  pus  has  been  detected  in  the 
veins,  and  still  more  extraneous  bodies,  which 
may  have  been  either  accidentally  or  designedly 
inserted  into  the  ulcerated  part.f  But  it  is 

*  Ed.  Med.  Journ.  vol.  xvii.  p.  455  ct  seq. 
On  the  absorption  of  foreign  bodies  see  the  early 
experiments  of  Lister  and  Musgrave,  Ph.  Trans, 
for  1683  and  1701  ;  also  Lowthorp's  Abrid.  vol.  iii. 
p.  101  .  .5,  and  La  Motte's  Abrid.  par.  2.  ch.  iv. 
p.  75,  6' ;  with  Haller's  sanction  of  their  accuracy, 
£1.  Phys.  xxiv.  2.  3  ;  see  also  J.  Hunter,  in  Med. 
Com.  p.  44  et  seq.,  and  Cruickshank,  ch.  viii. 
On  the  other  hand,  the  experiments  of  M.  Magendie 
and  his  friends  would  lead  us  to  form  an  opposite 
conclusion  ;  Elem.  t.  ii.  p.  168,  9.  See  Elliotson's 
Physiol.  p.  126. 

t  See  the  experiments  of  Mr.  Key,  in  Med. 
Chir.  Trans,  vol.  xviii.  p.  212,  13. 


not  unreasonable  to  suppose  that  in  these  in- 
stances, in  consequence  of  the  erosion  and 
partial  destruction  of  the  organs,  the  small 
branches  of  the  veins  will  present  an  external 
orifice,  through  which  the  pus  or  other  ex- 
traneous substance  may  be  immediately  re- 
ceived into  the  sanguiferous  system,  nearly 
upon  the  same  principle  as  in  the  experiments 
related  above. 

The  experiments  of  MM.  Magendie  and 
Flandrin,  the  results  of  which  were  so  opposite 
to  those  of  Hunter,  do  not  indeed  lie  open  to 
the  same  objection  ;  but  even  here  there  is 
perhaps  some  ground  for  inquiry,  before  we 
implicitly  adopt  the  conclusion  that  has  been 
deduced  from  them.  The  experiment,  as  origi- 
nally performed  by  Hunter,  necessarily  implies 
a  degree  of  mechanical  violence,  which  must 
produce  a  considerable  derangement  of  the 
actions  of  the  parts  concerned.  Acute  inflamma- 
tion of  a  peculiarly  irritable  and  sensitive  organ 
must  have  ensued,  the  vessels  of  all  descriptions 
must  have  become  much  distended ;  rupture 
and  extravasation  may  have  been  not  an  impro- 
bable consequence  of  this  inflammation  and 
distention,  and,  in  short,  a  general  derangement 
both  of  structure  and  functions  may  have  oc- 
curred, which  must  prevent  us  from  drawing 
any  positive  inference  respecting  their  natural 
condition. 

These  observations  will  apply  with  much 
greater  force  to  a  subsequent  variation  of  the 
experiment,  which  consisted  in  entirely  detach- 
ing a  portion  of  the  intestine  from  the  remainder 
of  the  tube,  and  filling  this  divided  portion  with 
the  fluid,  which,  as  in  the  former  case,  was 
detected  in  the  vein  of  the  mesentery.  This 
arrangement  was  supposed  to  afford  a  still  more 
decisive  proof  of  venous  absorption  than  the  ex- 
periment in  its  original  state,  and  if  we  con- 
sider the  mechanical  disposition  of  the  organ 
only,  we  may  admit  that  this  would  be  the 
case.  But  it  is  obvious,  on  the  other  hand,  that 
the  vital  actions  of  all  the  parts  concerned  must 
have  been  much  more  deranged,  and  that,  on 
this  account,  we  ought  to  be  proportionally  cau- 
tious in  the  application  of  such  experiments  to 
our  physiological  theories. 

We  would  venture  to  suggest,  that  the  re- 
markable discrepancy  which  exists  between  the 
experiments  of  Hunter  and  of  the  French  phy- 
siologists may  perhaps  be  reconciled,  by  having 
recourse  to  the  supposition,  that  in  the  former 
case  there  was  less  violence  used  to  the  parts, 
and  that  they  were  left  more  in  their  natural 
condition;  whereas  M.  Magendie,  as  we  pre- 
sume, from  a  desire  to  render  the  effect  more 
certain  or  more  decisive,  either  produced  a 
greater  degree  of  distention  of  the  intestines, 
or,  in  some  other  way,  caused  a  greater  derange- 
ment of  the  parts,  so  as  to  produce  a  difference 
in  the  results.  But  this  idea  is  offered  merely 
as  a  conjecture,  from  which  we  do  not  venture 
to  deduce  any  of  our  conclusions. 

Upon  the  whole  we  feel  disposed  to  regard 
the  experiments  of  MM.  TiedemannandGmelin, 
and  those  of  an  analogous  kind,  in  which  extra- 
neous substances  were  found  in  the  venous  blood, 
and  in  some  of  the  secretions,  when  they  could 
not  be  detected  in  the  chyle,  as  more  directly 


28 


ABSORPTION. 


favouring  the  doctrine  of  venous  absorption, 
because  they  are  free  from  the  objection  which 
must  always  attach  to  those  operations,  where 
any  considerable  degree  of  mechanical  violence 
has  been  employed.  It  may  indeed  be  ob- 
jected, that  in  these  cases,  the  examination  of 
the  body  did  not  take  place  at  the  proper  point 
of  time;  that,  in  some  instances,  it  was  made 
at  too  early  a  period,  before  the  extraneous 
body  had  time  to  enter  the  lacteals,  and,  in 
other  cases,  not  until  it  had  left  them,  and  had 
been  discharged  from  the  thoracic  duct  into  the 
veins.  But  this  contingency  must  be  regarded 
as  rather  a  possible  than  a  probable  occurrence, 
and  it  is  obvious  that  if  any  considerable  num- 
ber of  experiments  were  performed,  we  can 
scarcely  suppose  it  to  exist. 

The  conclusion  that  we  are  disposed  to  draw 
from  all  the  facts  and  arguments  that  have  been 
brought  forwards  on  the  subject  is  in  favour  of 
the  possibility  of  venous  absorption,  at  least 
under  peculiar  circumstances  ;  at  the  same  time 
that  there  are  strong  anatomical  considerations, 
which  would  induce  us  to  suppose,  that  in  the 
ordinary  actions  of  the  system,  the  function  of 
absorption  is  confined  to  the  lacteals  and  the 
lymphatics.* 

§.  3.  Inquiry  into  the  mode  in  which  the  ab- 
sorbents act. — In  entering  upon  this  inquiry 
there  are  two  distinct  subjects  which  present 
themselves  for  our  consideration  ;  we  must  first 
ascertain  by  what  means  the  substances  that  are 
absorbed  enter  the  mouths  of  the  vessels,  and, 
in  the  second  place,  after  they  have  entered  the 
mouths,  how  they  are  conveyed  along  the  ves- 
sels themselves. 

With  regard  to  the  first  of  these  points  we 
may  remark,  that  while  there  is  so  much  uncer- 
tainty respecting  the  anatomical  and  physio- 
logical structure  of  the  mouths  of  the  lacteals, 
and  still  more,  while  we  are  completely  igno- 
rant of  that  of  the  lymphatics,  we  cannot  ex- 
pect to  arrive  at  any  definite  conclusion  con- 
cerning the  mode  of  their  action.  We  may, 
however,  venture  to  say,  that  there  is  strong 
reason  to  believe,  that  the  absorbents  terminate 
in  very  minute  or  capillary  vessels,  that  have 
open  mouths,  and  that  these  mouths  are  brought 
into  contact  or  close  approximation  with  the 
substances  to  be  absorbed.  Hence,  by  an  ana- 
logy, which  it  must  be  acknowledged  is  some- 
what vague,  the  action  of  these  minute  vessels 
has  been  referred  to  capillary  attraction.  But 

*  A  summary  of  M.  Magendie's  experiments  and 
deductions  is  contained  in  his  Journ.  t.  i.  p.  18  et 
seq.  and  his  Elem.  t.  ii.  238  .  .243  ;  on  this  subject 
see  also  Bichat,  Anat.  Gen.  t.  ii.  104,  5,  with  the 
remarks  of  Beclard,  p.  130.  We  must  not  omit  to 
notice  the  experiments  of  M.  Segalas,  who  by 
dividing  the  bloodvessels  of  a  portion  of  the  intes- 
tine, and  leaving  the  lacteals,  thus,  as  it  were,  re- 
versing the  experiments  of  M.  Magendie,  found  that 
no  absorption  took  place,  and  hence  concludes  that 
the  lacteals  do  not  possess  this  power  ;  Magendie's 
Journal,  t.  ii.  p.  117  et  seq.  So  singular  a  conclu- 
sion must, we  conceive,  lead  us  to  place  but  little  con- 
fidence in  the  result  of  such  complicated  experiments. 
Franchini  of  Bologna  thought  that  the  lymphatics 
absorb  "  la  sostanza  assimilabile,"  but  that  the  sub- 
stances which  do  not  directly  contribute  to  nutrition 
are  absorbed  by  the  veins  j  Consider.  Fisiol.  sull' 
Assorb.  p.  44. 


it  may  be  doubted  whether  in  this  inference,  as 
in  so  many  other  cases  of  physiology,  we  have 
not  been  misled  by  a  mere  nominal  resem- 
blance, and  have  applied  the  term  capillary  to 
the  action  of  the  lacteals,  because  it  had  been 
used  to  denote  their  dimensions.  Perhaps, 
strictly  speaking,  there  is  scarcely  a  single  cir- 
cumstance, in  which  the  action  of  the  lacteals 
can  be  assimilated  to  that  by  which  fluids  are 
taken  up  by  capillary  tubes.  The  structure 
and  consistence  of  the  tube  itself,  the  nature  of 
the  substance  on  which  it  is  supposed  to  act, 
and  their  relative  situation,  are  all  of  them 
more  or  less  different  from  what  occurs  in  the 
ordinary  cases  of  capillary  attraction.  And  if 
there  is  a  difficulty  with  respect  to  the  lacteals, 
where  we  have  at  least  some  indistinct  evidence 
of  the  mechanical  disposition  of  the  parts,  which 
may  seem  favourable  to  this  hypothesis,  in  a 
much  greater  degree  will  it  exist  with  respect 
to  the  lymphatics,  where  we  have  nothing  to 
direct  our  opinion,  except  the  analogy  which 
may  be  presumed  to  exist  between  the  two  spe- 
cies of  absorbent  vessels. 

In  consequence  of  these  difficulties,  and  of 
the  supposed  inadequacy  of  the  mechanical 
theory,  many  physiologists  have  had  recourse 
to  a  certain  specific  action  of  the  vessels,  and 
have  conceived  that  the  chyle  was  taken  up  by 
a  power,  which  has  been  supposed  to  be  ana- 
logous to  an  elective  attraction  between  the 
vessel  and  the  substance  that  is  absorbed.* 
There  are  indeed  many  circumstances  which 
would  appear  to  indicate,  that  a  certain  kind  of 
selection  is  exercised  by  the  mouths  of  the 
vessels,  for,  as  far  as  we  are  capable  of  judging, 
when  substances  possessed  of  the  same  con- 
sistence and  physical  properties  are  placed  in 
contact  with  these  mouths,  some  of  them  are 
received,  while  others  are  rejected.  But  we 
must  remark,  that  the  same  objection  may  be 
urged  against  this  as  against  the  former  expla- 
nation, that  the  term  elective,  which  is  borrowed 
from  the  chemical  relation  of  bodies  to  each 
other,  is  perhaps  as  little  applicable  to  the  case 
under  consideration  as  that  of  capillary,  which 
refers  more  to  their  mechanical  action. 

Discarding  therefore  all  these  analogical 
illustrations,  which  are  at  least  of  doubtful 
application,  we  may  remark,  that  the  lacteals 
ought  to  be  regarded,  like  every  other  part  of 
the  animal  frame,  as  vital  organs,  possessed  of 
appropriate  and  specific  powers ;  that,  in  this 
instance,  we  are  not  able  to  refer  to  any  general 
principle  the  train  of  events  now  under  con- 
sideration, and  that  we  must  therefore  be  satis- 
fied with  simply  stating  the  fact,  that  the  lac- 
teals have  the  power  of  taking  up  by  their 
extremities  certain  substances,  with  which  they 
are  in  close  approximation  ;  that,  for  the  most 
part,  the  substances  which  they  receive  are  the 
elements  of  the  chyle,  that  they  select  these 
from  the  contents  of  the  intestinal  canal,  and 


*  See  Bichat,  Anat.  Gen.  t.  ii.  p.  125;  Dumas, 
Physiol.  t.  ii.  p.  397,  8  ;  Young's  Med.  Lit.  p.  112  ; 
Bell's  Anat.  v.  iv.  p.  290.  M.  Magendie,  however, 
is  disposed  to  reject  all  these  hypothetical  explana- 
tions ;  Elem^t.  ii.  p.  162,3,  and  Journ.  t.  i.  p.  3. 
et  alibi. 


ABSORPTION. 


29 


that,  except  under  peculiar  circumstances,  they 
reject  every  other  substance.* 

When  the  elements  of  the  chyle  have  been 
received  into  the  lacteals,  it  appears  to  undergo 
a  certain  degree  of  elaboration,  by  which  it  is 
farther  assimilated  and  perfected,  an  operation, 
the  intimate  nature  of  which  we  are  unable  to 
explain,  but  which,  as  well  as  its  entrance  into 
the  mouths  of  the  vessels,  we  correctly  refer  to 
their  vital  action.  After  the  chyle  has  entered 
the  lacteals,  there  is  less  difficulty  in  conceiving 
the  subsequent  steps  of  the  process.  We  are  at 
least  able  to  generalize  the  operation,  by  referring 
it  to  contractility,  the  same  power  which  ori- 
ginates motion  in  other  parts  of  the  system. 
It  must,  no  doubt,  be  admitted,  that  the  exis- 
tence of  the  muscular  fibres  of  the  lacteals  has 
not  been  satisfactorily  demonstrated,  and  that, 
until  this  has  been  accomplished,  our  opinion 
can  only  be  regarded  as  hypothetical  :  but  we 
have  here  the  advantage  of  being  able  to  assign 
a  probable  and  sufficient  cause  of  the  effect, 
and  are  aware  of  the  point  towards  which  we 
must  direct  our  future  investigations^  Before 
we  conclude  this  branch  of  the  subject,  we  may 
remark  concerning  the  contents  of  the  lacteals, 
that,  under  ordinary  circumstances,  we  have 
no  decided  proof  of  these  vessels  containing 
any  substance  except  the  elements  of  the  chyle, 
and  that,  although  in  some  of  the  experiments 
referred  to  above,  extraneous  bodies  have  been 
occasionally  found  in  them  in  minute  quantity, 
these  cases  must  be  regarded  as  exceptions  to 
the  general  fact. 

With  respect  to  the  chyle  itself,  it  has  been 
a  subject  of  examination  by  the  chemists,  whe- 
ther its  properties  are  always  uniform  in  the 
same  animal,  or  class  of  animals,  under  the 
various  circumstances  of  age,  constitution,  and 
still  more  of  diet,  to  which  they  are  subject. 
But  it  may  be  necessary,  before  we  enter  upon 
this  inquiry,  to  premise  a  few  remarks  upon 
the  meaning  of  the  terms  chyme  and  chyle. 
By  the  older  physiologists  they  were  very  gene- 
rally employed  as  synonymous,  and  this  is  still 
the  case  with  some  of  the  modern  writers,  more 
especially  on  the  continent.^  A  clear  distinc- 
tion between  them  has,  however,  been  pointed 
out  and  recognized,  and  as  there  appears  to  be 
an  essential  difference  between  them,  it  is  desi- 
rable that  it  should  be  generally  adopted.  The 
first  of  these  substances  is  the  immediate  pro- 
duct of  the  action  of  the  gastric  juice  on  the 
aliment,  as  received  into  the  proper  digestive 
stomach,  while  the  latter  is  the  substance  which 
is  produced  by  a  subsequent  part  of  the  pro- 
cess of  digestion.  The  conversion  of  chyme 

*  See  the  remarks  of  MM.  Chaussier  and  Ade- 
lon,  ubi  supra,  p.  272  et  seq.  ;  also  Adelon, 
Physiol.  t.  iii.  p.  85  et  seq.  ;  and  Alison's  Out- 
lines, p.  79. 

t  This  is  essentially  the  doctrine  of  Haller,  Prim. 

.  Lin.  c.   xxv.    §.568.    Sheldon,  p.  28,  and   Cruik- 

shank,  c.  12,  are  advocates  for  this  doctrine  ;  but  it 

is  opposed  by  the  high  authority  of  Mascagni,  ps.  i. 

sect.  4.  p.  27,  8. 

t  This  appears  to  be  the  ca^e  with  M.  Rullier, 
art.  "  Chyme/'  in  Diet,  de  Med.  t.  v.  p.  241  .  .  4 ; 
M.  Addon,  however,  clearly  marks  the  distinction, 
Physiol.  t.  iii.  p.  25,  et  alibi. 


into  chyle  seems  to  commence  shortly  after  it 
leaves  the  stomach,  and  while  it  still  remains 
in  the  duodenum,  is  so  far  advanced  as  to  be 
reduced  into  a  condition  proper  for  being  re- 
ceived into  the  lacteals.  There  is,  however, 
reason  to  believe  that  the  completion  of  the 
process  takes  place  in  the  lacteals  themselves, 
and  even  that  it  is  not  until  the  chyle  arrives  at 
the  thoracic  duct,  or  at  least  at  the  great  trunks 
of  the  lacteals,  that  it  is  fully  elaborated.  The 
nature  of  the  change  which  the  chyme  expe- 
riences in  the  duodenum,  and  the  agents  by 
which  this  change  is  effected,  what  share  the 
secretions  of  the  part  itself,  the  bile,  or  the 
pancreatic  juice  have  in  the  operation,  are 
questions  that  still  remain  in  discussion,  and 
which  will  be  considered  in  the  appropriate 
parts  of  this  work.* 

For  the  analysis  of  the  chyle  we  are  prin- 
cipally indebted  to  Vauquelin,  Marcet,  and  to 
Dr.  Prout.  Vauquelin  employed  the  chyle 
of  the  horse,  as  taken  from  the  large  trunks 
of  the  lacteals  and  from  the  thoracic  duct.f 
The  experiments  of  Marcet  were  principally 
directed  to  the  inquiry,  how  far  the  chyle  of 
the  same  kind  of  animal  was  affected  by  dif- 
ferences in  the  diet,  according  as  it  consisted 
Eincipally  of  animal  or  vegetable  substances.l 
r.  Prout's  experiments  on  the  chyle  extended 
both  to  its  general  properties,  and  to  the  dif- 
ferences produced  by  different  kinds  of  diet, 
while,  in  addition  to  these  points,  he  entered 
into  a  very  interesting  examination  of  the  suc- 
cessive changes  which  it  experiences,  from  its 
first  entrance  into  the  lacteals  until  its  final 
deposition  in  the  thoracic  duct.§  The  result  of 
these  experiments,  as  far  as  our  present  inquiry 
is  concerned,  tends  to  shew  that  the  vegetable 
chyle  differs  somewhat,  in  its  physical  and 
chemical  properties,  from  that  of  animal  origin, 
and  that  the  chyle,  when  it  first  enters  the 
lacteals,  is  in  a  less  perfect  state,  while  it  be- 
comes more  assimilated  to  the  blood  in  pro- 
portion as  it  advances  towards  the  thoracic 
duct. 

With  respect  to  the  means  by  which  the 
animalization  of  the  chyle  is  perfected  after  it 
enters  the  vessels,  we  have  no  certain  informa- 
tion, and  we  have  scarcely  any  analogy  which 
may  assist  in  guiding  our  opinion.  What  is 
termed  by  modern  physiologists  the  action  of 
the  vessels,  by  which  so  many  operations  of  the 
animal  economy  are  supposed  to  be  effected, 
we  may  regard  rather  as  an  expression  which 
serves  as  a  convenient  veil  for  our  ignorance, 
than  as  throwing  any  light  upon  the  process. 
We  have  no  evidence  that  any  addition  is  made 
to  the  chyle  while  in  the  lacteals ;  and  indeed 
we  can  scarcely  suppose  it  possible  that  this  is 
the  case,  so  that  the  only  conceivable  effect  of 
this  action  is  reduced  to  the  motion  which  is 
imparted  to  the  chyle  by  the  alternate  contrac- 
tion and  relaxation  of  the  vessels,  in  conse- 

*  See  the  remarks  of  Adelon,  art.  "  Chyliferes." 
Diet,  de  Med.  t.  v. 

t  Ann.  China,  t.  Ixxxi.  p.  113  et  seq. ;  Ann.  Phil. 
v.  ii.  p.  220  et  seq. 

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

§  Ann.  Phil.  v.  xiii.  p.  2^ . .  5. 


30 


ABSORPTION. 


quence  of  which  the  constituents  may  be  more 
completely  mixed  together,  and  to  a  certain 
degree  of  pressure  and  temperature  to  which  it 
is  exposed,  which  may  modify  any  spontaneous 
change  that  might  otherwise  take  place  in  the 
arrangement  of  its  elements.  But  to  whatever 
cause  it  may  be  referred,  we  must  consider  the 
chemical  and  physical  change  in  the  nature  of 
the  chyle  as  one  effect  produced  by  the  lacteals, 
as  well  as  the  progressive  motion  which  is  im- 
parted to  their  contents. 

In  the  present  state  of  our  knowledge  on  the 
subject,  it  remains  for  us  to  consider  whether 
we  have  any  independent  evidence  of  the  exist- 
ence of  the  muscular  fibres  of  the  absorbent 
vessels,  whether,  if  their  existence  be  proved, 
and  their  contractility  thus  established,  it 
would  be  necessary  for  us  to  search  out  for 
other  causes  of  the  effects,  and  lastly,  to  what 
other  principle  the  acknowledged  effects  might 
be  attributed,  should  it  appear,  upon  full  con- 
sideration, that  the  assigned  cause  is  insufficient 
or  inadequate. 

The  above  considerations  lead  us  to  give  an 
account  of  the  hypothesis  of  the  action  of  the 
absorbents,  which  has  been  proposed  by  M. 
Magendie.  He  had  ascertained,  by  a  previous 
train  of  experiments,  that  according  to  the  con- 
dition of  the  system  as  to  depletion  or  plethora, 
the  process  of  absorption  was  respectively  acce- 
lerated or  retarded.  Hence  he  draws  the  con- 
clusion, which,  however,  we  conceive  not  to  be 
a  necessary  consequence  of  the  premises,  that 
the  function  depends  on  a  mere  mechanical 
principle,  independent  of  any  vital  action.  The 
mechanical  principle  to  which  he  has  recourse, 
and  which  he  thinks  can  alone  account  for  the 
effect,  is  that  of  capillary  attraction ;  but  this  he 
conceives  not  to  take  place  from  the  open 
mouths  of  the  vessels,  according  to  the  ordinary 
conception  of  the  subject,  but  that  the  fluid  is 
imbibed  by  the  substance  of  the  vessel  itself, 
and  is,  as  it  were,  filtered  through  its  pores.* 
He  explains  its  further  progress  by  supposing, 
that  when  it  has  entered  these  pores,  it  is  car- 
ried forwards  by  the  current  of  the  fluid  pre- 
viously in  the  vessel. 

To  prove  his  idea  of  the  permeability  of  the 
parietes  of  the  vessels,  he  instituted  a  series  of 
experiments  on  the  veins  of  an  animal  shortly 
after  death,  when  he  found  that  they  were 
capable  of  imbibing  and  transmitting  certain 
fluids  with  which  they  were  placed  in  contact. 
Still  farther  to  substantiate  the  hypothesis, 
M.  Magendie  repeated  a  set  of  analogous  ex- 
periments on  the  vessels  of  a  living  animal. 
They  consisted  essentially  in  detaching  a  por- 
tion of  one  of  the  great  veins,  and  applying  to 


i.  p.  6  et  seq.  and  Diet,  de  Med. 
.    "  Absorption,"  t.  i.  p.  91  et  seq. 


*  Journ.   t. 

et  Chir.  Prat.  "  Absorption,"  t.  i.  p.  yi  et  seq. 
The  doctrine  of  transudation  was  maintained  by 
many  of  the  older  physiologists ;  see  Kauw  Boer- 
haave,  de  Persp.  ;  also  Haller,  El.  Phys.  ii.  2.  23  ; 
more  lately  it  was  supported  by  W.  Hunter,  Med. 
Com.  ch.  5 ;  by  Walter,  ubi  supra,  §  28  .  .  35  ;  and 
by  Mascagni,  ps.  1.  sect.  i.  and  is  zealously  main- 
tained by  his  commentator  Bellini,  t.  i.  not.  4. 
p.  33  .  .  0.  The  "  penetrabilite"  of  the  cellular  tex- 
ture was  one  of  the  fundamental  doctrines  of  Bordeu, 
Recherches  sur  le  Tissue  muqueux,  §  72. 


its  surface  the  solution  of  some  narcotic  or 
poisonous  substance,  the  effects  of  which  were, 
in  a  short  time,  manifested  in  the  system  at 
large* 

This  doctrine  of  imbibition  and  transudation 
has  been  embraced  by  M.  Fodera,  who  has 
endeavoured  to  confirm  the  opinion  of  M.  Ma- 
gendie by  additional  experiments,  which  he 
conceives  tend  directly  to  prove  that  the  vessels 
of  the  living  body  possess  this  power  of  im- 
bibition. The  method  which  he  adopted  to 
prove  this  point,  in  the  most  unequivocal  man- 
ner, was  to  inject  into  two  separate  cavities  of 
the  body  two  fluids,  which  by  their  union  pro- 
duce a  compound,  the  presence  of  which  may 
be  easily  detected,  and  which  could  be  formed 
by  no  other  means  except  by  this  union.  For 
example,  into  the  cavities  of  the  pleura  and 
the  peritoneum  were  respectively  injected  the 
solutions  of  the  ferro-prussiate  of  potash  and  of 
the  sulphate  of  iron,  when  it  was  found,  after  a 
certain  length  of  time,  that  various  membranes 
and  glands,  connected  with  the  thorax  and  the 
abdomen,  were  tinged  with  a  blue  colour. 

M.  Magendie  afterwards  performed  an  ex- 
periment, which  seemed  more  directly  to  bear 
upon  the  question,  where  a  solution  of  the 
ferro-prussiate  was  retained  in  a  portion  of  the 
intestine,  at  the  same  time  that  its  external 
surface  was  placed  in  contact  with  a  solution 
of  the  sulphate  of  iron :  the  part  was  then  ex- 
posed to  the  galvanic  influence,  the  result  of 
which  was  that  a  blue  tinge  was  communicated 
to  the  sulphate.  We  are  further  informed,  that 
according  to  the  direction  of  the  galvanic  cur- 
rent, the  blue  colour  was  produced  either  in 
the  sulphate  or  in  the  ferro-prussiate.  From 
these  experiments  M.  Fodera  draws  the  con- 
clusion, that  the  processes  of  absorption  and  of 
exhalation  may  be  referred  to  the  mechanical 
operations  of  imbibition  and  transudation,  which 
take  place  through  the  pores  or  capillary  open- 
ings of  the  various  textures  of  the  body.f 

On  these  experiments,  and  the  conclusion 
deduced  from  them,  we  shall  remark,  that  the 
facts  appear  to  prove  that  membranes,  perhaps 
during  life,  and  certainly  after  death,  before 
any  visible  decomposition  has  taken  place,  are 
capable  of  transmitting  fluids  through  their  tex- 
ture; but  we  conceive  that  the  analogy  between 
this  case  and  that  of  the  entrance  of  chyle  into 
the  lacteals  is  so  incomplete,  that  we  can  draw 
no  inference  from  the  one  of  these  events  which 
can  be  fairly  applied  to  the  other.  Both  the 
mechanical  and  the  physiological  properties  of 
membranes  and  vessels  differ  much  from  each 
other,  while  the  nature  of  the  fluids  employed  in 

*  Journ.  t.  i.  p.  9,  10. 

t  "  Recherches  sur  1'Absorption  et  1'Exhalation," 
and  Magendie's  Journ.  t.  iii.  p.  35  et  seq. ;  see,  also 
JVIed.  Repos.  v.  xix.  p.  419,  et  Med.  Journ.  v.  xix. 
p.  488,  9.  On  this  subject  see  the  remarks  of 
Tiedemann,  Traite  de  Physiol.  par  Jourdan,  §  168. 
p.  242.  Mr.  Mayo  remarks,  that  the  principle  of 
imbibition  and  transudation  affords  a  more  easy  ex- 
planation of  the  experiments  of  MM.  Magendie 
and  Segalas,  than  that  of  venous  absorption  ;  Phy- 
siol. (3rd  ed.)  p.  97  et  seq.  See  the  remarks  and 
objections  of  Sir  D.  Barry,  Exper.  Researches, 
p.  80 . .  2  et  alibi ;  also  Elliotson's  Physiol.  p.  133. 


ABSORPTION. 


the  experiments  is  totally  different  from  any 
thing  to  which  the  parts  are  exposed  under 
ordinary  circumstances.  It  may  be  further 
remarked,  that  if  the  texture  of  the  vessels  is  so 
permeable  to  fluids  of  all  kinds  and  in  all 
directions,  it  is  difficult  to  conceive  of  any 
cause  which  can  retain  them  there  when  they 
have  entered,  and  which  should  prevent  their 
escaping  through  the  same  pores  when  any 
pressure  is  made  on  the  contents  of  the  vessels 
by  its  contractile  power  or  by  any  extraneous 
force. 

And  it  may  be  further  remarked  concerning 
these  experiments,  without  impugning  the  accu- 
racy or  the  dexterity  of  the  operator,  that  they 
imply  a  degree  of  minuteness  in  the  execution, 
and  of  attention  to  a  variety  of  concurrent  cir- 
cumstances, and  are  altogether  of  so  extremely 
delicate  a  nature,  as  to  render  it  undesirable  that 
any  physiological  conclusion  should  be  founded 
on  them.  If  a  single  bloodvessel  be  divided, 
however  minute,  and  its  extremity  be  exposed, 
or  even  if  a  single  cell  of  the  membranous 
texture  be  laid  open,  so  as  to  admit  of  the 
introduction  of  the  fluid,  the  essence  of  the 
experiment  is  destroyed,  and  its  results  must 
become  equivocal. 

Another  hypothesis  respecting  the  nature  of 
absorption  has  been  lately  brought  forward  by 
Sir  D.  Barry,  according  to  which  it  immediately 
depends  on  atmospheric  pressure,  either  ex- 
ercised directly  on  the  surface  of  the  body,  or 
acting  indirectly  on  the  absorbents  through  the 
medium  of  the  great  internal  cavities.  The 
experiments  on  which  the  hypothesis  rests  con- 
sisted in  introducing  a  portion  of  some  poison- 
ous substance  into  a  wound,  and  forming  a 
vacuum  over  it  by  means  of  a  cupping-glass; 
when,  by  contrasting  the  effect  of  the  poison  in 
this  case  with  that  which  ensues  from  the  same 
application  where  the  cupping-glass  was  not 
employed,  he  concludes  that  the  process  of  ab- 
sorption was  suspended  by  removing  the  at- 
mospheric pressure,  and  he  hence  infers  that 
this  pressure  is  the  cause  of  absorption.* 

The  results  of  these  experiments,  in  a  prac- 
tical point  of  view,  are  of  great  interest,  but 
with  respect  to  the  physiological  conclusion  that 
has  been  drawn  from  them,  there  are  various 
circumstances  to  be  taken  into  account,  which 
appear  not  to  have  been  duly  attended  to. 

In  the  first  place,  a  similar  kind  of  objection 
occurs  in  this  case  as  in  the  experiments  of 
MM.  Magendie  and  Delille  related  above,  that 
the  poison  was  introduced  into  a  wounded 
part,  and  would  therefore  be  immediately  mixed 
with  the  blood  and  carried  into  the  general 
circulation.  The  effect  of  a  vacuum  formed 
over  the  divided  extremity  of  a  vessel,  must  be 
to  retard  the  progress  of  its  contents,  whatever 
be  its  description,  or  in  whatever  cause  it  ori- 
ginates. This  effect  is  therefore  not  specifically 
applicable  to  absorption,  even  in  the  natural 
state  of  the  parts ;  and  when  we  consider  that 
in  this  case  there  was  an  artificial  opening 

*  Barry's  Exper.  Researches,  pt.  2  "  On  Ab- 
sorption ;"  Alison's  Outlines,  p.  85  ;  Bostock's  Phy- 
siol.  v.  ii.  p.  593  et  seq. 


made  into  the  vessel,  we  may  venture  to  affirm 
that  the  conclusion  which  was  drawn  from  it  is 
in  no  respect  the  necessary  inference  from  the 
facts. 

And  besides  this  general  objection,  it  may  be 
fairly  questioned  how  far  the  removal  of  pres- 
sure from  the  surface  of  the  body  could  act  in 
retarding  the  progress  of  a  fluid  along  a  vessel 
which  has  no  external  opening,  and  which  is 
provided  with  valves,  such  as  is  strictly  the 
case  with  the  lacteals,  and  may  be  almost  said 
to  be  so  with  the  lymphatics.  And  with  re- 
spect to  the  lacteals,  it  appears  a  very  obvious 
objection  to  the  hypothesis,  that  they  are  alto- 
gether defended  from  the  effects  of  atmospheric 
pressure,  either  as  applied  directly,  or  as  in- 
directly acting  on  them  through  the  medium  of 
any  of  the  internal  cavities.  Besides,  we  have 
sufficient  proof  of  the  spontaneous  and  inde- 
pendent action  of  these  vessels,  whatever  may 
be  our  opinion  respecting  the  existence  of  their 
muscular  coat,  and  to  whatever  principle  we 
may  refer  this  action,  and  we  have  thus  an 
actual  cause  for  the  propulsion  of  their  con- 
tents, although  it  is  impossible  to  estimate  its 
actual  amount,  it  would  appear  unnecessary  to 
search  for  any  farther  agent,  unless  we  have 
good  ground  for  concluding  that  the  existing 
cause  is  inadequate  to  produce  the  effect  re- 
quired. 

Cutaneous  absorption, — There  is  a  branch 
of  the  subject  to  which  we  must  now  direct 
our  inquiry,  the  existence  and  extent  of  what 
has  been  termed  cutaneous  absorption.  When 
we  trace  the  progress  of  the  lymphatic  vessels 
from  their  great  central  trunks,  and  follow  them 
through  all  their  minute  ramifications,  we  find 
that  many  of  them  appear  to  have  their  origin 
from  the  surface  of  the  body,*  and  hence  we 
are  led  to  suppose  that  the  function  of  ab- 
sorption is  exercised,  to  a  certain  extent,  by  the 
cutis,  or  the  parts  immediately  connected  with 
it.  That  this  is  the  case  is  proved  by  various 
pathological  facts;  we  have  daily  opportunities 
of  observing,  that  various  medicinal  substances, 
by  mere  application  to  the  surface,  and  still 
more  when  aided  by  friction,  produce  the  same 
effect  upon  the  system  as  if  they  had  been 
received,  in  the  ordinary  way,  through  the 
medium  of  the  stomach.  By  this  means 
mercury  manifests  its  specific  action  on  the 
salivary  glands,  the  salts  of  lead  destroy  the 
contractility  of  the  muscular  fibre,  while  opium, 
tobacco,  and  other  narcotics  produce  their  pe- 
culiar effects  on  the  nervous  system. 

But,  besides  this  kind  of  absorption,  which 
is  brought  about  by  the  substances  being,  as  it 
were,  mechanically  forced  into  the  pores  of  the 
skin,  and  thus  applied  to  the  mouths  of  the 
lymphatics,  it  was  an  opinion  very  generally 
embraced  by  the  older  physiologists,  and  still 
retained  by  many  of  our  contemporaries,  that 
the  lymphatics,  which  are  distributed  over  the 
surface,  possess  the  power  of  imbibing  water, 
when  simply  applied  to  it  by  the  immersion 
of  the  body,  or  even  when  it  is  exposed  to 

*  See  Haase,  De  Vas.  Cut.  et  Intest.  Absorb., 
tab.  fig.  2  j  also,  Mascagni,  tab.  2.  fig.  9.  . 28,  tab.  3. 


32 


ABSORPTION. 


aqueous  vapour  diffused  through  the  atmos- 
phere. This  supposed  power  of  cutaneous  ab- 
sorption was  called  in  to  account  for  various 
physiological  or  pathological  facts,  for  which 
it  appeared  to  afford  a  plausible  explanation, 
while,  on  the  other  hand,  the  easy  mode  in 
which  it  appeared  to  account  for  these  facts 
was  made  use  of  as  the  great  argument  to 
prove  its  existence.  The  statical  experiments 
of  Sanctorius,  which  have,  since  his  time, 
been  so  much  multiplied  and  extended,  were 
supposed  to  prove  unequivocally  that  the  body 
is  capable  of  gaining  weight  independently  of 
any  substance  received  into  the  stomach,  and 
to  account  for  this  addition,  recourse  was 
always  had  to  the  cutaneous  absorption.  Of 
late,  indeed,  it  has  been  discovered,  that  a  part 
of  the  effect  ascribed  by  Sanctorius  to  the 
action  of  the  skin  is  in  reality  due  to  the  lungs, 
but  still,  after  making  the  necessary  deduction 
for  the  operation  of  the  latter  organ,  there  re- 
mained a  certain  increase  of  weight,  which  it 
was  supposed  could  only  be  accounted  for  by 
admitting  the  existence  of  the  cutaneous  ab- 
sorption.* 

The  doctrine  of  cutaneous  absorption  has, 
however,  been  altogether  called  in  question  by 
Seguin,  who  performed  a  series  of  experiments, 
which  consisted  in  immersing  a  part  of  the 
body  in  a  saline  solution,  for  example,  that  of 
corrosive  sublimate,  the  effects  of  which  on  the 
system  at  large  would  be  easily  recognized, 
if  any  part  had  been  absorbed.  The  result 
was,  that  when  the  cuticle  was  entire,  no  effect 
that  could  be  attributed  to  absorption  took 
place,  and  the  conclusion  seemed  not  unna- 
tural, that  under  ordinary  circumstances  it  did 
not  exist,  f  Currie  was  led  to  form  the  same 
conclusion  by  accurately  weighing  the  body 
before  and  after  immersion  in  the  warm  bath, 
under  circumstances  which  were  conceived  to 
be  favourable  to  the  process,!  and  as  the  re- 
sults of  his  experiments  coincided  with  those 
of  Seguin  and  others,  the  doctrine  of  cuta- 
neous absorption,  except  under  the  particular 
circumstances  mentioned  above,  was  very 
generally  abandoned.  Experiments  have  been 
adduced  to  prove,  that  even  under  these  par- 
ticular circumstances,  when  substances  are  ap- 
plied by  friction  to  the  surface,  they  do  not 
enter  into  the  mouths  of  the  vessels,  but  being 
volatilized  by  the  heat  of  the  body,  that  the 
vapour  thus  produced  is  inhaled  by  the  lungs  ;§ 
an  opinion  which  one  might  be  inclined  to 
think  was  almost  too  extravagant  to  be  seri- 
ously maintained. 

The  subject  of  cutaneous  absorption  has 
been  lately  investigated  by  Dr.  Edwards,  with 
that  skill  and  address  which  he  has  applied  to 
so  many  departments  of  physiology.  By  a 
number  of  experiments,  which  were  performed 
on  cold-blooded  animals,  where  it  was  more 

*  Mascagni,  p.  22,  3;  see  also  Kellie,  in  Ed. 
Med.  Journ.  v.  i.  p.  170  et  seq.j  and  the  article 
"  Integuments  "  in  Rees's  Cyclop. 

t  Fourcroy,  Med.  Eclair,  t.  iii.  p.  232.  .  241,  and 
Ann.  Chim.  t.  xc.  p.  185  et  seq. 

$  Med.  Reports,  ch.  xix. 

§  Ed.  Med.  Journ.  v.  ii.  p.  10  et  scq. 


easy  to  observe  the  effects,  he  found  that  ab- 
sorption was  carried  on,  to  a  considerable 
extent,  when  the  animal,  or  a  part  of  it  was 
immersed  in  water.  The  conclusion  which 
the  experiments  seemed  to  warrant  was,  that 
transudation  and  absorption  are,  at  all  times, 
going  forwards  at  the  surface,  but  that  the 
operations  proceed  at  different  rates,  according 
to  the  circumstances  in  which  the  animal  is 
placed,  and  that  the  body  gains  or  loses  weight, 
in  proportion  to  the  excess  of  one  of  them 
above  the  other.  The  analogy  of  the  cold- 
blooded animals  he  applies  to  those  with  warm 
blood,  and  he  supposes  that  they  are  subject 
to  the  same  double  action,  a  conclusion  which 
appears  to  be  confirmed  by  some  experiments 
that  were  performed  on  guinea-pigs  immersed 
in  moist  air,  when  an  increase  of  weight  was 
found  to  have  taken  place,  which,  after  taking 
every  circumstance  into  consideration,  seemed 
necessarily  to  depend  on  absorption.*  With 
respect  to  the  experiments  of  Seguin,  Dr.  Ed- 
wards is  not  disposed  to  call  their  accuracy  in 
question,  but  he  points  out  various  circum- 
stances connected  with  them,  which  he  con- 
ceives would  tend  to  increase  the  transudation, 
and  to  diminish,  or  even  entirely  to  suspend 
the  absorption.f  The  experiments  of  Dr.  Ed- 
wards, considered  in  all  their  relations,  are 
generally  conceived  to  decide  the  question 
respecting  the  existence  of  cutaneous  absorp- 
tion, under  the  ordinary  circumstances,  and  in 
the  natural  conditions  of  the  system. 

§.4.  Of  the  specific  uses  of  the  different 
parts  of  the  absorbent  system,  and  of  the  rela- 
tion which  that  system  bears  to  the  other  vital 
functions. — Whatever  opinion  we  may  form  on 
the  controverted  question  respecting  venous 
absorption,  and  in  whatever  manner  we  may 
explain  the  action  of  the  lacteals  and  the  lym- 
phatics, there  can  be  no  doubt  that  their  spe- 
cific use  is  to  absorb  certain  substances  which 
are  presented  to  their  extremities.J  There  is, 
however,  so  well  marked  a  distinction  between 
the  situation  and  the  anatomical  relations  of 
these  two  kinds  of  vessels,  as  well  as  between 
the  substances  that  are  found  to  be  contained 

*  De  1'Influence  des  Agens,  &c.  ch.  xii.  p.  345 
et  seq. 

t  De  1'Influence,  &c.  ch.  xiii.  p.  556  et  seq. 
See  on  this  subject,  Magendie/Physiol.  t.  ii.  p.  189 .  . 
196,  and  Diet,  de  Med.  et  Chir.  Prat.  "  Absorp- 
tion ;"  where  he  endeavours  to  prove,  that  it  is  the 
veins  and  not  the  lymphatics  which  are  the  agents 
in  cutaneous  absorption.  See  also  the  remarks  of 
M.  Rullier,  ch.  ii. ;  and  of  M.  Adelon,  Physiol. 
t.  iii.  p.  10  et  seq. ;  also  art.  "  Absorption/' 
Diet,  de  Med.  t.  i.  p.  124  et  seq.  M.  Chaussier 
found  that  sulphuretted  hydrogen  gas,  when  ap- 
plied to  the  surface  of  the  body,  manifested  its 
deleterious  effects  on  the  system,  Bibl.  Med.  t.  i. 
We  have  already  had  occasion  to  notice  the  opinion 
of  Walter  on  this  subject,  p.  25,  which  is  similar 
to  that  of  M.  Magendie.  M.  Buisson  attempts  to 
establish  a  distinction  between  the  absorption  which 
is  carried  on  by  the  membranes  and  by  the  cellular 
texture,  De  la  Divis.  des  Physiol.  Phenom.  p.  251 
et  seq. 

t  M.  Magendie  indeed  doubts  this  position  so 
far  as  the  lymphatics  are  concerned ;  Journ.  Phy- 
siol. t.  i.  p.  18  et  seq.  and  Physiol.  t.  ii.  p.  238. . 


ABSORPTION. 


in  them,  that  we  are  naturally  led  to  conclude, 
that  they  are  destined  for  different  uses,  and 
serve  different  purposes  in  the  animal  economy. 
With  regard  to  the  lacteals,  their  use  seems 
to  be  clearly  marked  by  their  connexion  with 
the  digestive  organs,  and  by  their  contents, 
as  constituting  the  channel  by  which  the  chyle 
is  conveyed  from  the  intestines  to  the  thoracic 
duct,  and  ultimately  to  the  bloodvessels.  We 
cannot  doubt  that  their  primary  function  is  to 
supply  the  body  with  the  elements  which  com- 
pose the  blood,  and  thus  become  the  imme- 
diate agents  in  its  nutrition.  Although,  from 
the  experiments  which  have  been  related 
above,  it  will  appear  that,  on  certain  occasions, 
the  lacteals  are  not  incapable  of  receiving 
extraneous  bodies,  yet  we  may  conclude,  that 
this  is  the  case  only  under  extraordinary  cir- 
cumstances, or  in  an  unnatural  state  of  the 
parts. 

With  respect  to  the  lymphatics,  their  specific 
use  is  less  obvious.  As  their  contents  are  ul- 
timately mixed  with  those  of  the  lacteals,  we 
may  suppose  that  they  contribute  indirectly  to 
the  nutrition  of  the  body;  but  this  would 
appear  not  to  be  their  primary,  or  even  their 
principal  destination.  Still  we  can  scarcely 
refuse  our  assent  to  the  position,  that  absorp- 
tion is  the  specific  function  of  the  lymphatics ; 
and  this  will  be  equally  the  case,  although  we 
may  suppose  that  the  veins  cooperate  with  them 
in  this  action. 

\Ve  are  indebted  to  the  genius  of  John  Hun- 
ter for  a  consistent  or  plausible  theory  of  the 
use  of  the  lymphatics,  which,  with  certain  mo- 
difications, is  generally  admitted  to  be  correct. 
Conceiving  that  the  appropriate  and  specific 
action  of  the  lacteals  is  to  nourish  the  body, 
and  to  support  the  system  by  the  addition  of 
new  matter,  that  of  the  lymphatics  is  to  mould 
and  fashion  the  body,  to  admit  of  the  growth 
and  extension  of  the  whole,  while  each  in- 
dividual part  retains  its  proper  form  and 
position.  When  we  consider  in  what  manner 
an  organized  part  increases  in  its  dimensions, 
we  immediately  perceive  that  it  is  not  by  mere 
accretion,  nor  by  simple  distention;  it  is,  on 
the  contrary,  by  an  addition  to  every  individual 
portion,  while  they  retain  the  same  relation  to 
each  other  and  to  the  whole.  If  we  take  the 
case  of  a  muscle,  we  find  that  each  particular 
fibre  must  be  increased  in  length,  so  that  the 
distance  may  be  augmented  between  the  ten- 
dinous extremities,  while  probably  the  number 
of  fibres  that  are  contained  in  the  membranous 
covering  is  also  increased ;  the  whole  organ 
consequently  becomes  larger  in  every  one  of  its 
individual  parts,  while  they  each  retain  their 
former  proportions  and  connexions.* 

We  may  apply  the  same  train  of  reasoning 
to  the  bones,  which  offer  a  still  more  remark- 
able, example  of  this  change  of  form,  inas- 


much as  the  firmness  of  their  texture  must 
render  it  less  easy  to  conceive  of  any  alteration 
in  their  dimensions  and  in  the  disposition  of 
their  component  parts.  Here  it  is  still  more 
obvious  than  in  the  case  of  the  muscle,  that 
the  change  cannot  be  effected  either  by  accre- 
tion or  by  distention,  but  that  a  completely 
new  disposition  of  the  integrant  parts  must 
have  taken  place.  The  only  means,  however, 
by  which  this  can  be  accomplished  is  by  the 
former  particles  of  the  body  being  gradually 
removed,  and  new  ones  deposited  to  supply 
their  place ;  the  process  being  so  gradual,  that, 
although  the  deposition  of  the  new  particle  is 
not  precisely  in  the  same  situation*  with  the1 
former,  yet  that  of  each  particle  is  so  nearly 
so  as  to  cause  no  obstruction  or  interruption 
to  the  action  of  the  organ.  Now  it  is  evident 
that  this  removal  of  the  old  matter  can  be 
effected  by  no  process  but  by  absorption,  and 
we  may  therefore  conclude  that  the  lymphatics, 
either  alone  or  in  conjunction  with  the  veins, 
are  the  agents  destined  to  perform  this  office. 

With  respect  to  the  actual  nature  of  the  con- 
tents of  the  lymphatics  there  appears  to  be 
some  uncertainty.  We  have  the  analysis  of 
the  fluid  taken  from  the  vessels  of  a  dog  by 
M.  Chevreul,*  from  which  it  would  appear 
that  the  lymph  contains  nearly  the  same  in- 
gredients with  the  blood,  but  diluted  with  a 
much  larger  proportion  of  water.  We  must, 
however,  suppose  that  the  fluid  contained  in 
the  lymphatics  will  vary  very  considerably  in 
its  composition,  according  to  the  part  of  the 
body  from  which  it  is  taken,  or  the  condition 
of  the  same  part  at  different  times ;  yet  we  are 
scarcely  able  to  detect  an  actual  state  of  things 
which  altogether  corresponds  with  what  we 
might  have  been  led  to  expect  would  have  been 
the  case.f  It  may  indeed  be  presumed  that 
in  the  ordinary  condition  of  the  system,  the 
process  by  which  the  parts  of  the  body  are 
absorbed  is  so  very  gradual,  that  the  change  in 
the  chemical  constitution  of  the  lymphatic 
fluid  is  as  inconspicuous  as  the  change  in  the 
organs  from  which  it  is  absorbed,  and  that  it 
is  only  in  morbid  cases,  where  there  is  some 
extraordinary  quantity  of  matter  to  be  re- 
moved, that  we  should  expect  to  be  able  to 
detect  it  in  the  lymph.  And  this,  to  a  certain 
extent,  agrees  with  the  fact;  for  when  the  ab- 
sorbents are  called  into  action  to  remove  col- 
lections of  pus,  or  when  they  become  the 
vehicles  of  any  poisonous  or  morbid  body, 
the  substance  in  question  has  been  occasionally 
found  in  them. 

The  doctrine  of  the  removal  or  absorption  of 
all  the  parts  of  the  body  is  rendered  evident  by 
a  variety  of  cases,  in  which  any  particular 
organ  or  texture  is  broken  down  or  removed, 
merely  by  cutting  off  the  supply  of  fresh  matter. 
It  is  upon  this  principle  that  we  explain  the 


*  See  Winterbottom,  de  Vas,  Absorb,  in  Smel- 
lie's  Thes.  Med.  t.  iv.  ;  also  Cruikshank,  p.  108,  9. 
For  the  more  recent  views  of  physiologists  on  the 
subject  the  reader  is  referred  to  Adelon,  art. 
"  Absorption/'  Diet,  des  Scien.  Med.  t.  i. 
VOL.  I. 


*  Magendie,  Elem.  t.  ii.  p.  171,  2. 

t  Magendie,  Elem.  t.  ii.  p.  196,  7,  et  alibi. 
Mascagni,  however,  states  that  the  lymph  varies 
according  to  the  parts  to  which  it  is  contiguous, 
ps.  1.  §.  4.;  see  also  Blumenbacb,  §.  438. 

D 


34 


ABSORPTION. 


removal  of  a  part  by  pressure.  If  a  muscle,  or 
even  a  solid  bone  be  exposed  to  constant  pres- 
sure, by  which  its  nutritive  arteries  are  ob- 
structed, it  will  be  gradually  diminished  in 
bulk,  and  at  length  completely  abstracted. 
And  this  is  frequently  effected  by  the  action  of 
a  body  much  softer  than  the  substance  which 
is  removed,  as,  for  instance,  we  observe  a  bone 
to  be  absorbed  by  the  pulsation  of  a  blood- 
vessel, or  the  growth  of  a  fleshy  tumour.* 

But  although  we  may  venture  to  affirm  that 
this  moulding  of  the  body,  or  rather  of  its  in- 
dividual parts,  is  effected  by  the  lymphatics, 
either  alone  or  in  conjunction  with  the  veins, 
there  is  considerable  difficulty  in  forming  a 
distinct  conception  of  the  mode  in  which  they 
operate.  The  operation  cannot,  strictly  speak- 
ing, be  mechanical,  nor  have  we  any  evidence 
of  the  existence  of  a  chemical  solvent,  by 
which  the  parts  may  be  reduced  to  a  liquid 
state,  so  as  to  fit  them  for  entering  into  the 
mouths  of  the  vessels.  We  may  conceive  of 
the  source  of  supply  being  cut  off  by  pressure 
or  in  other  ways,  but  still  we  are  at  a  loss  to 
account  for  the  mode  in  which  the  solids  are 
either  dissolved  or  broken  down,  so  as  to  adapt 
them  to  the  process  of  absorption.  There  is, 
however,  one  principal  or  general  fact  in  the 
animal  economy,  which  will  probably  some- 
what assist  us  in  our  inquiry,  viz.  that  it  appears 
to  be  essential  to  the  well-being,  or  even  to  the 
existence  of  the  corporeal  frame,  that  all  the 
materials  of  which  it  is  composed  should  un- 
dergo a  constant  change.  It  appears  that  these 
materials,  after  a  certain  length  of  time,  expe- 
rience some  alteration  in  their  nature,  by  which 
they  are  rendered  unfit  for  the  further  perform- 
ance of  their  functions  as  constituents  of  the 
living  body.  They  are  therefore  removed  and 
are  replaced  by  fresh  matter,  this  interchange 
being  brought  about  in  the  gradual  manner 
which  was  described  above.  Now  this  process 
implies  a  constant  decomposition  of  the  parts 
of  the  body,  and  as  this  decomposition  is 
effected  particle  by  particle,  it  may  not  be  un- 
reasonable to  conjecture,  that  each  particle, 
when  it  ceases  to  form  an  integral  part  of  an 
organ,  is  left  in  a  state  proper  for  being  taken 
up  by  the  absorbents.  But  independent  of  any 
hypothetical  views  of  this  description,  we  may 
assume  it  as  a  probable  conclusion,  that  the 
configuration  and  moulding  of  the  body  is  the 
specific  and  appropriate  office  of  the  lymphatics, 
•while  its  nutrition  is  effected  more  immediately 
by  the  lacteals. 

With  respect  to  the  lymphatic  glands  we 
have  seen  above  that  their  structure  is  involved 
in  considerable  obscurity,  and  we  may  remark, 
that  their  use  is  at  least  equally  obscure.  Among 
other  opinions  that  have  been  entertained  on 

*  For  the  absorption  of  the  solids,  see  Monro  on 
the  Brain,  c.  5 ;  also  Blumenbach,  §.  436 ;  and 
Bell's  Anat.  vol.  iv.  p.  311,  2.  Ribes,  who  is  a 
zealous  defender  of  the  doctrine  of  venous  absorp- 
tion,-,remarks  that  the  absorption  of  the  bones  must 
be  effected  by  the  veins,  because  they  are  not  fur- 
nished with  lyirphatics ;  Mem.  Soc.  d'Emulation, 
t.  viii.  p.  621. 


the  subject,  some  physiologists  have  supposed 
that  the  glands  are  proper  secreting  organs, 
which  are  destined  for  the  purpose  of  preparing 
a  peculiar  substance  that  is  mixed  with  the 
chyle  and  the  lymph,  or  that  they  merely  serve 
the  mechanical  purpose  of  mixing  together  more 
completely  the  constituents  of  the  fluid  that  is 
contained  in  the  vessels,  and  thus  produce 
some  change  in  its  nature  or  consistence.* 
There  do  not  appear  to  be  any  arguments,  either 
anatomical  or  physiological,  by  which  this  point 
can  be  decided ;  but  we  may  remark,  that 
while  the  number  and  mode  of  distribution  of 
these  glands  in  the  mammalia  would  seem  to 
point  them  out  as  performing  some  important 
office  in  the  animal  economy,  their  rarity  in 
birds  and  fishes  proves  that  they  are  not  essen- 
tial to  the  existence  of  most  of  the  functions  of 
animal  life,  nor  have  we  any  mode  of  explaining 
the  cause  why  they  should  be  more  necessary 
to  the  mammalia  than  to  the  other  classes, 
which  in  many  of  their  functions  so  nearly  re- 
semble them. 

It  only  remains  for  us  to  offer  a  few  remarks 
on  the  connexion  between  the  function  of  ab- 
sorption, and  the  other  vital  actions  of  the 
system,  especially  with  the  two  leading  princi- 
ples of  contractility  and  sensibility.  We  have 
already  had  occasion  to  remark  on  the  con- 
nexion of  absorption  with  muscular  contracti- 
lity, and  although  it  may  be  difficult,  or  even 
impossible,  to  demonstrate  the  muscular  fibres, 
or  to  exhibit  any  apparatus  of  this  description, 
by  which  the  action  of  the  vessels  can  be  ac- 
counted for,  still  we  have  strong  reason  for 
supposing  that  the  absorbents  possess  this 
power,  and  that  it  is  the  main  cause  by  which 
their  contents  are  propelled. 

With  respect  to  the  relation  which  subsists 
between  the  nervous  and  the  absorbent  systems, 
we  are  induced  to  suppose,  both  from  anato- 
mical and  from  physiological  considerations, 
that  it  is  merely  of  an  indirect  nature.  From 
the  researches  of  the  anatomists,  we  learn  that 
there  are  few  nerves  sent  to  the  absorbent  vessels 
or  glands,  and  that  even  these  seem  rather  to 
pass  by  them,  in  order  to  be  transmitted  to 
some  other  organs,  than  to  be  ultimately  des- 
tined for  the  use  of  the  absorbent  system.  The 
action  of  the  mouths  of  the  lacteals,  or  the 
power  by  which  they  are  enabled  to  take  up 
the  substances  that  are  afterwards  transmitted 
along  them,  is  involved  in  much  obscurity,  as 
is  likewise  the  case  with  the  power  which  these 
vessels  seem  to  possess  of  changing  the  nature 
pf  their  contents.  Both  of  these  have  been  re- 
ferred to  the  nervous  influence,  but  this  has 
been  done  in  that  loose  and  general  way,  which 


*  On  this  subject  we  may  refer  to  Haller,  El. 
Phys.  ii-  3.  25;  Bltimenbach,  Inst.  Phys.  §.  425, 
442;  Richerand,  Elem.  p.  153;  Mascagni,  ps.  i. 
sect.  5.  p.  33  ;  Magendie,  Elem.  t.  ii.  p.  166,  201  ; 
Chaussier  et  Adelon,  ubi  supra,  p.  278.  Rullier, 
art.  "  Inhalation,"  in  Diet.  Sc.  Med.  ;  Meckel, 
Manuel,  sect.  6.  ch.  i.  ;  Adelon,  art.  "  Lymphatique 
(Physiologic),"  Diet,  de  Med.  t.  xiii,  also  art. 
"  Chyliferes,"  ibid.  t.  v.  p.  239;  Desgenettea, 
Journ.  Med.  t.  xc.  p.  322,  et  seq. 


ACALEP11/K. 


35 


is  too  frequently  met  with  in  the  reasoning  of 
physiologists.  We  do  not  perceive,  in  either 
case,  how  it  can  be  referred  to  this  power,  nor 
how  it  can  be  employed  in  any  way  to  explain 
or  elucidate  the  e fleets  that  are  produced.* 

It  is  admitted  that  the  chyle  is  elaborated 
during  its  passage  along  the  lacteal s,  and  be- 
comes more  nearly  assimilated,  both  in  its  phy- 
sical and  chemical  properties,  to  the  blood. 
Still,  however,  its  complete  sanguification  does 
not  take  place  until  it  leaves  the  lacteals,  and 
it  becomes  a  very  interesting  subject  of  inquiry, 
by  what  means  this  is  effected ;  in  what  degree 
the  function  of  respiration  contributes  to  it, 
whether  the  abstraction  of  carbone  and  the  in- 
troduction of  oxygene,  which  is  supposed  to  be 
effected  by  the  passage  of  the  blood  through 
the  lungs,  is  the  immediate  cause  of  the  con- 
version of  chyle  into  blood  ;  whether  it  be 
brought  about  more  gradually,  by  the  removal 
of  the  various  secretions  and  excretions,  or 
whether  there  be  any  particular  organ,  which 
may  more  especially  produce  the  change  in 
question.  These  are  all  of  them  points  of  high 
interest,  but  as  they  are  concerned  in  an  indi- 
rect manner  only  with  the  subject  of  this  article, 
and  as  they  will  be  considered  in  the  appro- 
priate parts  of  this  work,  we  shall  not  pursue 
the  inquiry  any  further. 

BIBLIOGRAPHY.  —  Abernethy,  in  Phil.  Trans. 
1776  and  1796.  Adelon,  in  Diet.  Scien.  Med. 
"  Absorption"  and  "  Lymphatique  /'  Ditto,  Phy- 
siologie  ;  Ditto,  in  Diet,  de  Med.  "  Absorption  " 
and  "  Chyliferes."  Albinus,  Tab.  Vas.  Chyl.  fol. 
Lugd.  Batav.  1757.  Alison's  Outlines  of  Physio- 
logy. Aselli,  de  Lactibus.  4to.  Mediol.  1627. 
Antommarchi,  Prodromo  di  Mascagni ;  Ditto,  in 
Ann.  Se.  Nat.  t.  xviii.  Barry's  Exper.  Researches. 
8vo.  Lond.  1826.  Bartholin,  De  Lact.  Thor. ; 
Ditto,  Anat.  Reform-  Ditto,  Vas.  Lymph,  hist, 
nov.  12mo.  Hafn.  1652,  &c.  Beclard,  add.  a 
Bichat.  Bell's  Anat.  Bellini,  Istor.  Vas.  linf.  di 
Mascagni.  Bichat,  Anat.  Gen.  Bleuland,  Exper. 
Anat.  1784.  Blumenbach's  Comp.  Anat.  by  Law- 
rence. Boerftaave,  Prelect,  a  Haller.  Boliut,  in 
Haller,  Disp.  Anat.  t.  i.  Bordeu,  sur  le  Tissu 
Muqueux.  Bostock's  Physiol.  Boyer,  Anat.  Bre 
schet,  in  Diet,  de  Med.  "  Lymph.  Syst."  Buisson, 
Divis.  de  Phys.  Phen.  Chaussier,  in  Diet.  Scien. 
Med.  "  Lymphatique."  Ditto,  in  Bibl.  Med.  t.  i. 
Cheselden't  Anat.  Cloquet,  Manuel.  Coopei,  in 
Med.Rec.  and  Res.  Cruikshank,  on  the  Absorbents  ; 
Ditto,  Letter  to  Clare.  4to.  Lond.  1786.  Currie'i 
Med.  Rep.  Desgenettes,  in  Journ.  Med.  t.  Ixxxiv. 
Douglas,  Bibl.  Anat.  Dumas,  Physiol.  Duvernoi, 
in  Mem.  Petrop.  t.  i.  Edwards,  sur  FInfluence  des 
Agens,&c..  Elliotson's  Physiol.  5th  edit.  Eustachii 
Oper.  Anat.  Fallopii  Opera.  Feller,  Vas.  Lymph. 
Desc.  Flandrin,  in  Journ.  de  Med.  t.  Ixxxv,  Ixxxvii, 
xc.  Fleming's  Zoology.  Fodera,  Recherch.  sur  1'Ab- 
sorption  ;  Ditto,  in  Magendie's  Journ.  t.  iii.  Foh- 
mann,  Commun.  Lymph,  et  Veines.  4to.  Liege. 
1832.  Fourcroy,  in  Ann.  Chim.  t.  xc.  ;  Ditto, 
Medecine  Eclairee.  Franchini,  Consid.  fisiol.  sull' 
Assorb.  Galeni  Opera,  a  Charterio.  Glisson, 
Anat.  Hepat.  12mo.  Lond.  1654.  Gordon's  Anat. 
Graves,  Lect.  on  the  Lymph.  Sys.  House,  Vas. 
Cut.  et  Inst.  Abs.  Haller,  Bibl.  Anat.;  Ditto, 
Elem.  Phys.  •,  Ditto,  Opera  Min. ;  Ditto,  Prim. 

*  On  this  subject  the  reader  is  referred  to  Mas- 
cagni, p.  30;  Hewson,  pt.  3.  p.  52  j  Cruikshank, 
p.  64  ;  and  Gordon's  Anat.  p.  77. 


Lineae.  Hedwig,  Disq.  Ainpull.  Lieb.  Hewson's 
Knqiiiiios  ;  Ditto t  in  Phil.  Trans.  1768,  9. 
Hodgkin,  Appendix  to  his  Translation  of  Edwards 
Sur  Ics  .Agens,  &c.  J.  Hunter,  in  Med.  Com. 
W.  Hunter,  Mod.  Com.  Kauw  Boerhaavc,  De 
Perspir.  Kcllie,  in  Ed.  Med.  Journ.  vol.  i.  Key, 
in  Med.  Chir.  Trans,  vol.  xviii.  Kiernan,  in 
Phil.  Trans.  Ib33.  La  Motte's  Ah.  of  Phil.  Trans. 
Lauth,  Sur  les  Vaiss.  Lymph.  4to.  Strasb.  1824. 
Lieberkuekn,  Fab.  Vill.  Intest.  Lippi,  Illust. 
Fisiol.  Loiothorp's  Ab.  of  Phil.  Trans.  Lyster,  in 
Phil.  Trans.  1683.  Mtujendie,  Physiol.;  Ditto, 
Journal  de  Physiol.  ;  Ditto,  in  Diet.  Med.  <  t  Chir. 
Prat.  "Absorption."  Marcet,  in  Med.  Chir.  Tr. 
vol.  vi.  Wufaagni,  Vas.  Lymph.  Hist.  fol.  Senis, 
1787.  Mayo's  Physiol.  Meckd,  Diss.  de  Vas. 
Lymph.  4to.  Berol.  1757;  Ditto,  Manuel  d'Ana- 
tom.  par  Jourdan  et  Kresrhct ;  Ditto,  sur  Re- 
sorption,  in  Nouv.  Mem.  Berl.  1770;  Ditto, 
de  Fin.  Ven.  et  Lymph.  4to.  Berol.  1772.  Monro 
(1),  de  Seui.  et  Test,  in  Smellie,  t.  ii.  ;  Ditto, 
de  Venis  Lymph.  8vo.  Berol.  1757. ;  Ditto, 
on  Fishes  ;  Ditto,  on  the  Nervous  System  ; 
Ditto,  Three  Treatises.  Monro  (3),  Elem.  of 
Anat.  Musgrave,  in  Ph.  Tr.  1701.  Nuck,  Ade- 
nologia.  12mo.  Lugd.  Batav.  1691.  Panizxa, 
Osservazione.  Pecquet,  Exper.  Nov.  Anat.  4to. 
Paris,  1651.  Portal,  Mem.  Acad.  1770.  Prout, 
in  Ann.  Phil.  vol.  xiii.  Quain's  Elem.  of  Anat. 
Rees's  Cyclop.  Ribes,  in  Mem.  Soc.  d'Emulat.  t.  viii. 
Richerand,  Elem.  Physiol.  ;  Ditto,  par  Berard. 
Rudbek,  Nov.  Exerc.  Anat.  4to.  Ares.  1653. 
Rullier,  Diet,  de  Med.  "  Chyme ;"  Ditto,  Diet. 
Sc.  Med.  ««  Inhalation."  Ruysch,  Dilucid.  Valv. 
Sabatier,  Med.  Acad.  1786.  Salzmann,  in  Haller, 
Disp,  Anat.  t.  i.  Santorini,  Tabulae,  fol.  Parmae. 
1775.  Segalas,  in  Majendie's  Journ.  t.  ii.  Sheldon, 
on  the  Abs.  Sys.  fol.  Lond.  1784.  Soemmering, 
Corp.  Hum.  Fab.;  Ditto,  de  Morbis  Vasor.  Abs. 
8vo.  Traj.  ad  Man.  1795.  Tiedemann,  Physiol. 
par  Jourdan.  Valentin,  in  Journ.  de  Med.  t.  Ixxxvi. 
Vauquelin,  in  Ann.  Chim.  t.  Ixxxi  ;  Ditto,  in  Ann. 
of  Phil.  vol.  ii.  Veslinq,  Synt.  Anat.  Walter,  in 
Nouv.  Mem.  Berlin,  1786,  7.  Watson,  in  Phil. 
Trans.  1769.  Werner,  Vas.  Lact.  et  Lymph.  Desc. 
Winterbottom,  De  Vas.  Abs.  in  Smellie,  t.  iv. 
Wrisberg,  Observ.  Anat.  Vas.  Abs.,  in  Com.  Gott. 
t.  ix.  Young's  Medical  Literature. 

(J.  Bostock.) 

ACALEPH^E  (from  axaA»jp»j,  a  nettle);  syn. 
urtica  marina.  Fr.  Acalcphes;  Germ.  Acalep hen; 
the  name  of  a  class  of  invertebrate  animals. 
They  are  all  inhabitants  of  the  sea,  and  are  such 
as  are  commonly  known  by  the  names  of  sea- 
jelly,  sea-nettle,  Portuguese  man-of-war,  £c. 
It  is  from  the  property,  which  many  of  these 
animals  possess,  of  irritating  the  surface  of  our 
skin  so  as  to  produce  nearly  the  same  effect 
as  that  resulting  from  the  sting  of  a  common 
nettle,  that  the  class  derives  its  name. 

Aristotle  used  the  word  ax<*A>?<p»)  to  de- 
signate some  of  these  animals ;  but  it  was  by 
Cuvier  that  the  class  was  formed,  and  the 
term  acalephae  applied  to  it.  As  this  class  now 
stands  in  the  last  edition  of  the  Regne  Ani- 
mal, (t.  iii.  p.  274,)  it  is  formed  chiefly  by 
the  animals  constituting  the  Linnaean  genus 
Medusa  and  les  acalephes  hydrostatiques  of 
Cuvier. 

On  many  accounts  the  acalephae  are  objects 
of  extreme  interest  to  the  anatomist  and  phy- 
siologist. They  have  occupied  the  attention 
of  the  most  learned  naturalists  of  every  age, 
from  the  time  of  Pliny  until  the  present  day  ; 
their  numbers  are,  perhaps,  greater  than  those 

D  2 


36 


ACALEPIM. 


of  any  other  class  of  marine  animals :  they  exist 
in  all  seas ;  and  yet  we  remain  very  ignorant 
with  regard  to  several  points  in  their  structure 
and  history.  The  peculiar  nature  of  their 
tissues,  the  singular  arrangements  of  their  organs, 
the  anomalies  in  their  functions,  present  as  many 
objects  of  interesting  inquiry  to  the  physiologist, 
as  the  wonderful  variety  and  striking  elegance 
of  their  forms,  and  their  splendid  colouring 
present  to  the  admiration  of  the  naturalist. 
Peron,*  in  his  animated  description  of  the  Me- 
dusa, observes,  "Among  the  animals  of  this 
family  we  find  the  most  important  functions  of 
life  performed  in  bodies  which  offer  to  the  eye 
1  ittle  more  than  a  mass  of  j  elly .  Th  ey  grow  fre- 
quently to  a  large  size,  so  as  to  measure  several  feet 
indiameter;  andyetwe  cannot  always  determine 
what  are  their  organs  of  nutrition.  They  move 
with  rapidity,  and  continue  their  motions  for 
a  long  time  ;  and  yet  we  cannot  always  satis- 
factorily demonstrate  their  muscular  system. 
Their  secretions  are  frequently  very  abundant, 
and  yet  the  secreting  organs  remain  to  be  dis- 
covered. They  seem  to  be  too  weak  to  seize  any 
vigorous  animal,  and  yet  fishes  are  sometimes 
their  prey.  Their  delicate  stomachs  appear  to  be 
wholly  incapable  of  acting  upon  such  food, 
and  yet  it  is  digested  within  a  very  short  time. 
Most  of  them  shine  at  night  with  great  bril- 
liancy, and  yet  we  know  little  or  nothing  of 
the  nature  of  the  agent  which  produces  so  re- 
markable an  effect,  or  of  the  organs  by  which 
it  is  elaborated.  And,  lastly,  many  of  them 
sting  the  hand  which  touches  them ;  but  how, 
or  by  what  means,  they  do  so  still  remains  a 
mystery."  It  is,  therefore,  but  a  very  imperfect 
account  of  the  anatomy  and  physiology  of  this 
class  that  can  be  at  present  given. 

The  following  are  the  names  and  characters 
of  the  groups  into  which  the  acalephse  have 
been  divided  by  M.  De  Blainville,f  whose 
arrangement  is  nearly  the  same  as  that  adopted 
by  Eschscholtz.  J 

I.  PHYSOGRADA.  Body  regular,  symme- 
trical, bilateral,  fleshy,  contractile,  often  very 
long,  provided  with  an  aeriferous  sac.  Bran- 
chiae in  the  form  of  long  cirri,  very  con- 
tractile. 

1.  Organ  of  natation  simple  and  lamellated. 
Gen.  Physalus.    (Physalia,  Lam.) 

2.  Locomotive  organs  complex  and  vesicular. 
Gen.  Physsophora.     Diphysa.     Rhizophysa. 

3.  Locomotive  organs  in  the  form  of  smooth 
scales,    disposed   in  transverse   series.      Gen. 
Stephanomia.    Agalma.     Protomedea.     Rho- 
dophysa. 

II.  DIPHYDA.  Body  bilateral  and  symme- 
trical, composed  of  a  visceral  mass  of  small 
size  and  of  two  swimming  organs,  hollow, 

*  Peron.  Ann.  du  Mus.  xiv.  220. 

t  Diet,  des  Sc.  Nat.  ««  Zoophytes."     1830. 

t  System  der  Acalephen.  Berlin,  1829.  The 
most  complete  treatise  on  the  anatomy  and  history 
of  the  acalepha  hitherto  published.  Its  learned 
author  enjoyed  excellent  Opportunities  of  studying 
these  animals  in  the  course  of  the  two  voyages 
round  the  world  undertaken  by  Kotzebue,  of  whose 
expeditions  he  was  naturalist. 


contractile,  somewhat  cartilaginous,  and  placed 
one  before  the  other,  the  anterior  one  being 
in  more  direct  connexion  with  the  central 
visceral  mass,  which  it  seems  to  surround ; 
the  other  posterior,  and  very  slightly  adherent. 
Mouth  at  the  extremity  of  a  stomach  more 
or  less  extensile.  Anus  unknown.  A  long 
filamentary  organ,  ovigerous,  rises  from  the 
root  of  the  central  mass,  and  is  prolonged 
more  or  less  posteriorly. 

Gen.  Cucubalus.  Cucullus.  Cymba.  Cu- 
boides.  Enneagona.  Amphiroa.  Calpe. 
Abyla.  Diphyes.  Ersaea.  Eudoxia.  Py- 
rarnis.  Praia.  Tetragona.  Sulculeolaria. 
Galeolaria.  Rosacea.  Noctiluca.  Doliolum. 

III.  CILIOGRADA.     (Ctenopkora,    Esch.) 
Body  gelatinous,  free,  varying  in  form,  marked 
on  the  surface  with  narrow  ambulacra  formed 
by   rows  of  vibratile  cilia.      Intestinal  canal 
complete,  with  two  orifices.* 

Gen.  Beroe.  Eucharis.  Mnenia.  Cal- 
ymma.  Axiotoma.  Callianira.  Pandora. 
Medea.  Alcynoe.  Cestum.  Cydippe.  Idya. 

IV.  PULMOGRADA.     ( DiscophortE,   Esch.) 
Body    entirely    gelatinous,    circular,    without 
any    solid   part    internally,    margin    provided 
with  cirri  of  various    forms,  or  with  foliace- 
ous    appendages    pendent  from    the   inferior 
surface. 

1.  Simple :  without  true  tentacula,  peduncles 
or  arms. 

Gen.  Eudora.  Ephyra.  Phorcynia.  Eu- 
lymene.  Carybdea.  Euryale. 

2.  Tentaculated  :    the   circumference  of  the 
body,  and  sometimes  the  mouth,  surrounded 
by  tentacula. 

Gen.  Berenice.  Equorea.  Foveolia.  Pe- 
gasia.  Cunina.  ./Egina.  Eurybdia.  Thau- 
mantias.  Obelia.  Linuche.  Eirene. 

3.  Subproboscic :    gastric   cavity  prolonged 
into  a  short  peduncle,  at  the  extremity  of  which 
is   the   mouth,    surrounded   by   four  brachial 
appendages. 

Gen.  Oceania.  Aglaura.  Melicerta.  Sa- 
phenia.  Tima. 

4.  Proboscic :    the   lower   and  central    part 
of  the  body  prolonged    into  a  proboscis-like 
appendage,    either  simple  or   provided   with 
arms. 

Gen.  Orythia.  Geryonia.  Dianoaa.  Fa- 
vonia.  Cytaeis. 

5.  Brachigerous :    lower  surface  furnished 
with  more  or  less  numerous  appendages,  bra- 
chial, ramified. 

Gen.  Ocyroe.  Cassiopea.  Medusa  (Au- 
relia  of  Peron).  Callirhoe.  Melitea.  Eva- 
gora.  Cephea.  Rhizostoma.  Chrysaora. 
Cyanea.  Pelagia.  Sthenonia. 

V.  CIRRIGRADA.       ( Velellido:,      Esch.) 

*  M.  De  Blainville  regards  the  animals  included 
in  this  and  the  two  preceding  sections  as  being 
more  allied  in  structure  to  the  Mollusca,  (his  Mala- 
cozoaires,)  than  to  the  Radiata,  with  which  they  are 
arranged  by  most  zoologists.  Accordingly  he  sepa- 
rates them  from  the  two  succeeding  sections,  which 
are  truly  radiate  animals,  and  of  which  he  forms 
a  class  in  his  great  division  Actinoxouires,  under  the. 
name  of  Araohnoderma. 


ACALEPII^E. 


Body  oval  or  circular,  gelatinous,  supported  by 
an  internal,  solid,  subcartilaginous  body,  and 
provided  with  very  extensile  tentacule-like 
cirri  pendent  from  the  whole  of  the  lower  sur- 
face. 

Gen.  Velella.  Porpita.  Rataria* 
Of  the  gen  era  above  enumerated,  Eschscholtr 
has  described  about  two  hundred  species. 
Messrs.  Quoy  and  Gaimard  have  made  us  ac 
quainted  with  several  others ;  but  of  all  these 
a  comparatively  small  number  only  have  been 
described  in  detail:  so  that,  although  in  the 
account  which  we  are  now  to  give  of  the 
anatomy  and  physiology  of  the  acalephse,  we 
shall,  for  the  sake  of  brevity,  make  use  of  the  /^~^ 
sectional  designations,  it  must  be  understood 
that  the  descriptions  apply  only  to  a  few 
species,  and  that,  with  regard  to  the  others 
grouped  along  with  these,  we  can  only  say 
it  is  probable  that  they  are  similarly  con- 
structed. 

I.  Locomotion.  The  principal  organ  of 
locomotion  in  the  physograda  is  the  air-filled 
vesicle  or  bladder,  which  exists,  of  various 
sizes,  in  all  the  species.  In  physalus,  (Fig.  6.) 
it  is  a  large  organ,  forming  a  great  portion  of 
the  general  mass  of  the  animal.  It  is  placed 


*  The  following  neat  but  artificial  arrangement 
of  acalephfs  forms  the  subject  of  a  communication 
lately  made  to  the  Zoological  Society  hy  M.  Lesson, 
foreign  member  of  that  body  :  we  are  indebted  for  it 
to  our  friend  Mr.  Owen. 

I.  Without  a  central  solid  axis. 

A.  Body  simple,  entire. 

1.  Symmetrical,     termi- 
nated at  each  pole  by 

an  opening     ....   1   Beroidce. 

2.  Non-symmetrical,   the 
upper  pole  disciform  or 
umbelliform,        imper- 

forate 2  Medusa;. 

B.  Body   multiple   or    aggre- 

gated. 

a.  Homogeneous. 

3.  Composed  of  two  pieces 
adhering  together,  and 

capable  of  separation    .  3  Dipltydcs. 

4.  Composed  of  numerous 
pieces  aggregated  toge- 
ther        4  Polytoma. 

b.  Heterogeneous. 

5.  Animal  furnished  with 
appendages  of  different 
kinds. 

*  Vesicle  small,  regular, 
placed  at  the  summit  of 
a  kind  of  stalk  fur- 
nished with  lateral  am- 
pullae, and  terminal 

suckers 5    Physsoph&ra?. 

**  Vesicle  large,  irregular, 
without  stalk  or  am- 
pullae, but  having  ter- 
minal suckers  and  cir- 
riferous  processes  .  .  6  Physa'.ice. 

II.  With  a  central  cartilaginous 

axis. 

6.  Body      simple,      with 
suckers  and  lateral  ten- 
tacula. 

a.  Body  irregularly  oblong, 

with  a  vertical  lamina 

on  its  upper  surface      .  7   Velellae. 

b.  Body  discoid,  flat  above.  8  Porpitae. 

R.  JJ.  T. 


superiorly,  and,  for  the  most  part,  rises  above 
the  surface  of  the  water.  It  has  an  elongated 
form ;  the  longest  diameter  being  the  hori- 
zontal. It  is  somewhat  pointed  at  one  end, 
at  the  other  truncated  ;  and  at  either  there  is 
a  small  opening,  the  place  of  which  is  marked 
by  a  superficial  dimple,  surrounded  by  delicate 
muscular  fibres,  acting  as  sphincters.  When 


(Fig.  Q.) 


Physalus  Utriculus,  (Esch.) 


the  bladder  is  squeezed  by  the  hand,  so  as  to 
force  the  contained  air  towards  one  of  these 
openings,  the  air  makes  its  escape  through  it  ; 
but  whenever  the  pressure  is  taken  off,  the 
opening  again  closes.  M.  De  Blainville  states 
that  he  has  satisfied  himself  that  this  air-blad- 
der is  really  a  dilatation  of  the  intestinal  canal; 
and  that  he  regards  the  two  openings  mentioned 
above  as  the  mouth  and  the  anus.  We  are 
ignorant  of  the  data  upon  which  M.  De  Blain- 
ville grounds  his  conclusion.  It  does  not  ap- 
pear that  any  observer  has  found  alimentary 
matter  lodged  within  the  air-sac.  But  whether 
or  not  it  be  an  organ  of  digestion,  it  is  cer- 
tainly an  organ  of  locomotion,  although  only 
a  passive  one  ;  for  it  is  by  its  contained  air  that 
the  animal  floats  on  the  surface  of  the  water, 
so  as  to  expose  a  large  superficies  of  its  crest 
and  bladder  to  the  wind,  by  which  it  is  driven 
to  and  fro  frequently  with  great  velocity.  The 
walls  of  this  sac  are  muscular,  so  that  by  their 
contraction  its  cavity  can  be  considerably  dimi- 
nished. And  thus,  partly  by  the  escape  of  air 
forced  out  through  the  openings,  and  partly  by 
the  compression  of  what  remains,  the  specific 
gravity  is  so  much  altered  as  to  admit  of  the 


38 


ACALEPII7E. 


animal's  sinking  into   the  deep  when  danger 
threatens.    In  the  other  physograda,  the  air-ve- 


Fig.  7. 


sicle  is  so  small  in  pro- 
portion to  the  general 
mass  of  the  animal  that 
it  is  not  sufficient  to 
raise  it  above  the  sur- 
face of  the  water.  It 
is  generally  an  ovate 
sac,  with  an  opening 
at  its  upper  end,  closed 
by  a  sphincter  muscle. 
It  is  probable  that  its 
walls  are  muscular, and 
that  by  pressing  out  a 
portion  of  the  contained 
air,  and  by  secreting 
more,  alternately  the 
animal  can  sink  and 
rise  at  pleasure.  The 
nature  of  the  air  con- 
tained in  these  vesicles 
has  not  yet  been  ascer- 
tained. In  rhizophysa 
( Fig. 7.)  there  are,  pen- 
dent from  one  part  of  the 
body,  certain  peculiar 
organs,  arranged  very  re- 
gularly in  pairs,  of  a  mus- 
cular structure,  hollow, 
and  furnished  each  with 
a  round  orifice.  They 
differ  from  the  tentacula 
in  structure,  and  are,  pro- 
bably, organs  of  natation,  i 
Similar  tubes,  but  only  / 
two  in  number,  exist  in  diphysa  ;  and,  anterior 


Rhizophysa  Melon. 


ings.  Their  attachment  is  so  slight  as  to  admit 
of  their  being  separated  by  agitation  of  the 
water.  It  is  at  the  bottom  of  the  anterior  ca- 
vity that  the  essential  parts  of  the  animal 
are  placed.  Locomotion  is  effected  by  means 
of  the  impulse  of  a  current  which  is  kept  up 
by  the  successive  contractions  and  dilatations  of 
the  organs  above  described.  The  contractions 
of  the  two  bodies  are  not  synchronous;  but 
they  succeed  one  another  within  a  short  time, 
so  that  a  steady  progression  is  maintained ; 
and  in  some  species  iUs  very  rapid. 

In  the  ciliograda,  the  locomotive  organs  are 
large  cilia,  disposed  in  longitudinal  bands  on 
the  surface  of  the  body.  These  bands  are  ge- 
nerally eight  in  number ;  but  in  some  species, 
(e.  g.  uxiotoma  Gaedii,  Esch  ,)  there  are  only 
four.  The  arches  supporting  the  cilia  are  of 
firmer  texture,  and  are  less  transparent  than 
the  rest  of  the  body.  In  many  species  they 
extend  from  one  end  of  the  body  to  the  other ; 
in  some  only  along  a  part  of  the  circumference. 
The  structure  of  the  cilia  themselves  has  lately 
Fig.  9. 


Fig.  8. 


Agalma  okenii. 


to  them,  in  the  same  animal, 
there  is  a  two-lobed  organ, 
the  use  of  which  is  doubt- 
ful. In  agalma,  (Jig.  8.)  and 
some  of  the  genera  allied  to 
it,  there  are  certain  cartila- 
ginous plates  disposed  in  an 
imbricated  manner  along  the 
sides  of  the  body.  These, 
Eschscholtz  regards  as  loco- 
motive organs.  The  mus- 
cles by  which  they  are  set  in 
motion  must  be  extremely 
delicate,  as  a  slight  touch  is 
sufficient  to  separate  the 
plates  from  one  another. 

The  chief  bulk  of  the  sin- 
gularly formed  diphyda  is 
made  up  of  the  swimming 
organs,  which  are  two  sub- 
cartilaginous  bodies,  poly- 
gonal, generally  pointed  an- 
teriorly, truncated  posteri- 
orly, placed  one  behind  the 
other,  and  one  a  little  within 
the  other;  the  posterior  por- 
tion being  lodged  in  a  little 
excavation  which  exists  in 
the  anterior.  These  two  parts 
differ  somewhat  from  one 
another  in  form,  but  both  are 
hollow,  and  have  large  open- 


Diphyes  Campanulifera. 

been  examined  by  Dr.  Grant,*  with  his  usual 
care,  in  the  Beroe pileu&;-\  and  he  has  found 
that  they  are  fin-like  processes,  and  that  each 
is  composed  of  several  short,  transparent,  some- 
what curved  filaments,  placed  parallel  to  each 
other  in  a  single  row,  and  connected  together 
by  the  skin  of  the  animal,  like  the  rays  sup- 
porting the  fin  of  a  fish.  The  rays  in  the 
middle  of  the  cilium  are  a  little  longer  than 
those  at  the  sides.  All  the  rays  appear  as 
transparent  tubes  under  high  magnifying  pow- 
ers. They  are  so  curved  that  their  extremities 
are  directed  backwards  towards  the  closed  ex- 
tremity of  the  animal.  There  are  about  forty 
cilia  attached  to  each  arch  in  this  species,  which 
is  nearly  an  inch  in  length.  The  cilia  are  so 
large  as  to  be  visible  to  the  naked  eye.  Most 
of  the  ciliograda  have  their  cilia  quite  exposed; 
but  Pandora  is  provided  with  moveable  folds 
of  the  skin  along  the  cilia-bearing  arches,  which 
can  be  brought  over  the  cilia,  in  whole  or  in 
part,  at  the  animal's  pleasure,  so  as  to  cover 
them  more  or  less  completely.  These  cilia  are 
moved  nearly  in  the  same  manner  as  the  pec- 
toral fins  of  fishes.  But  their  motion  is  so 
rapid,  when  the  animal  is  vigorous,  that  the 
eye  cannot  follow  it.  The  existence  of  motion 
is  pointed  out,  however,  by  lines  of  beautiful 
iridiscent  colours  playing  along  the  arches,  and 

*  Trans.  Zool.  Soc.  of  London,  i.  10. 
t  Pleurobrachia  pileus.      Fleming.   Brit.  Anim. 
504.     Cydippe  p.  Esch. 


ACALEPH/E. 


39 


by  the  currents  which  are  generated  in  the  cir- 
cumambient fluid.  The  animal  has  the  power 
of  arresting  completely  the  motion  of  one,  two, 
or  more  rows  of  eiha,  while  the  others  are 
moving.  \N  hen  all  are  set  in  motion  together, 
the  animal  moves  onwards  with  the  inferior  or 
oral  surface  (inferior  in  a  slate  of  rest)  d;rectt d 
forwards,  \\hen  the  motion  of  some  is  ar- 
rested, the  whole  body  acquires  a  rotatory  mo- 
tion, and  advances  in  a  curvilinear  path.  The 
animal  has  also  the  power  of  changing  the 
direction  of  the  currents  caused  by  its  cilia,  so 
that  it  can  ascend  or  descend  in  the  water  at 
pleasure.  It  can  also  increase  and  diminish  at 
will  the  velocity  of  the  motions  of  the  cilia. 
Those  animals  which  have  the  largest  cilia,  (e.  g. 
J\Iedca,)  swim  with  the  greatest  rapidity.  The 
cilia  continue  to  move  for  some  time  after 
having  been  separated  from  the  body,  in  con- 
nexion with  part  of  their  arches.  Immediately 
beneath  the  arches  there  are  vessels  conveying 
a  fluid,  which  is  in  motion  during  the  vibrations 
of  the  cilia.  Whether  these  vessels  are  destined 
only  for  the  conveyance  of  the  circulating  fluid 
to  the  cilia,  (which  in  all  probabi'ity  act  as 
organs  of  respiration  as  well  as  of  locomotion,) 
or  carry  a  stimulus  fitted  to  excite  their  vibra- 
tions, is  not  yet  determined.  Eschscholtz  com- 
pares these  vessels  to  those  which  Tiedemann 
has  described  as  connected  with  the  feet  in  the 
echinodermata.  And  Dr.  Grant  is  of  opinion, 
with  MM.  Audouin  and  Milne  Edwards, 
that  it  is  not  improbable  that  the  motions  of  the 
cilia  are  somehow  dependent  on  the  movements 
of  the  fluids  contained  in  the  above-mentioned 
vessels,  seeing  that  in  the  actinia  the  tentacula 
are  projected  by  water  being  forced  from  below 
into  them.  In  the  other  classes  of  the  acalephae 
also  the  same  kind  of  structure  prevails.  Such 
of  the  pulmograda  as  have  cilia  around  their 
margins  have  also  circular  vessels  running  along 
their  bases;  and  almost  all  projectile  and  exten- 
sile tentacules  and  filaments  are  provided  with 
sacs  and  canals,  containing  fluids,  at  their  roots. 
In  addition  to  their  cilia,  several  of  the  cilio- 
grade  acalephae  have  other  organs  of  locomo- 
tion in  the  form  of  long  filamentary  arms  or  ten- 
tacules, with  which  they  can  poise  themselves 
in  the  water  without  moving  their  cilia.  In  Cy- 
dippe*  these  are  two  in  number.  They  are 
lodged  in  two  tubes  placed  alongside  of  the  sto- 
mach, from  which  they  issue  near  the  mouth. 
They  can  be  extended  to  four  times  the  length 
of  the  animal.  They  terminate  in  very  fine 
points,  and  along  their  whole  course  present 
minute  filaments  placed  at  equal  distances, 
which  are  coiled  up  spirally,  close  to  the  ten- 
tacules, when  these  are  about  to  be  withdrawn 
into  their  sheaths.  The  tentacules  are  also 
coiled  up  in  a  spiral  form  when  completely 
contracted.  They  are  sometimes  suddenly  sent 
forth  from  their  tubes  to  their  full  length  by 
one  impulse,  and  then  their  lateral  filaments 
are  gradually  uncoiled  ;  a  process  this  of  no  less 
interest  on  account  of  the  gracefulness  of  the 
motion  than  on  account  of  the  peculiar  mecha- 
nism which  it  indicates. 

*  Grant.  Trans.  Zool.  Soc.  i.   10. 


The  principal  organ  of  motion  in  the  pulmo- 
gnida  is  the  large  campuiulale,  or  mushioom- 
shaped,  disc,  of  gelatinous  consistence,  which 
constitutes  the  great  mass  of  the  animal.  Jn 
this,  for  the  most  part,  no  muscular  fibres  can 
be  seen,  mid  yet  the  animals  move  about  with 
some  quickness.  They  have  the  power  of  con- 
tracting and  dilating  their  discs  at  pleasure,  in 
whole  or  in  part.  By  alternately  contracting 
and  dilating  their  inferior  surface,  they  strike 
the  water  in  such  a  manner  and  with  such  force 
as  to  raise  themselves ;  when  they  discontinue 
this  motion,  they  again  sink,  being  of  greater 
specific  gravity  than  the  sea-water.  They  move 
onwards  horizontally,  by  acting  only  with  one 
side  of  the  margin  of  their  disc.  Lamarck 
was  of  opinion  that  these  isochronous  move- 
ments of  the  disc,  by  means  of  which  the  pul- 
mograda seem  to  swim,  were  fitted  merely  to 
facilitate  the  internal  vital  processes,  and  not 
to  move  the  animals  through  the  water ;  and 
he  regarded  them  as  dependent  entirely  on  the 
influence  of  imponderable  agents  existing  in 
the  circumambient  fluid,  and  alternately  enter- 
ing into,  and  flowing  from,  the  general  mass  of 
the  animal.  He  compared  the  motions  with 
those  of  the  fiV.d  in  Franklin's  thermoscope, 
when  held  in  the  hand.*  In  the  course  of  the 
ordinary  progression  of  the  large  Medusa  aurita 
of  our  seas,  the  contractions  of  the  disc  take 
place  from  twelve  to  fifteen  times  in  a  minute. 
The  convex  surface  of  the  disc  always  advances 
foremost. 

No  fibrous  structure  has  hitherto  been  dis- 
covered in  the  general  mass  of  the  disc.  In- 
ternally, it  is  cellular,  uniform,  and  very  soft. 
The  quantity  of  solid  matter  in  the  disc,  and, 
indeed,  in  the  whole  body,  is  very  small. 
Some  medusa,  which,  when  recently  taken  out 
of  the  water,  weighed  fifty  ounces,  on  being 
dried,  left  remains  weighing  scarcely  more  than 
five  or  six  grains.  "  It  is  therefore  evident, 
that  the  sea-water,  penetrating  the  organic  tex- 
ture, constitutes  the  greater  part  of  the  volume 
of  these  animals."  f  But  in  some  species  there 
exists  a  fine  muscular  membrane,  stretched 
over  a  certain  extent  of  the  lower  surface  just 
within  its  outer  margin.  Under  a  lens,  this 
has  the  appearance  of  being  composed  of  nu- 
merous fleshy  fibres,  forming  little  bundles, 
arranged  in  a  radiate  manner  as  regards  the 
axis  of  the  animal,  and  closely  adherent  to  the 
gelatinous  tissue  of  the  disc.  When  portions 
of  the  disc  are  cut  off  from  living  medusa, 
without  any  part  of  this  muscular  membrane 
being  attached  to  them,  they  remain  motionless; 
but  when  their  connexion  with  the  membrane 
is  preserved,  even  small  portions  continue  their 
motions  of  contraction  and  dilatation  for  a 
considerable  time. 

The  tentacula  of  the  pulmograda  (which  are 
always  pendent  from  the  inferior  surface)  may 
be  regarded  as  supplementary  organs  of  loco- 
motion, although  they  are,  in  all  probability, 
subservient  chiefly  to  the  nutritive  function. 
They  are  all  simple,  not  branched,  generally 

*  Anim.  sans  Vert.  ii.  454. 

t  Spallanzani,  Travels  in  the  Two  Sicilios,  iv 
218. 


ACALEPHjE. 


Rhizostoma  ccerulea. 

hollow;  and,  when  connected  with  the  appen- 
dages of  the  digestive  cavities,  or  when  they  have 
a  vesicle  at  their  base,  very  extensile.  Several 
genera  have  suckers  at  the  extremities,  and 
along  the  sides,  of  their  tentacula,  by  means  of 
which  the  passing  prey  is  seized.  The  tenta- 
cula which  are  extensile  seem  to  be  projected 
by  the  forcing  of  water  into  their  internal  cavity, 
by  the  contractions  of  the  vesicles  at  their  base. 
The  extent  to  which  the  filamentary  organ  is 
thus  lengthened,  in  some  species,  is  very  extra- 
ordinary.* It  seems  to  be  shortened  again  by 
means  of  the  contractions  of  circular  muscles, 
which  force  back  the  water  into  the  vesicle,  and 
of  longitudinal  muscles  which  draw  it  in. 
Peron  thought  that  some  of  the  pulmograda 
were  furnished  with  internal  air-bladders ;  but 
Eschscholtz,  on  directing  his  attention  to  this 
point,  satisfied  himself  that  what  Peron  had 
taken  for  air-bladders  were  merely  appendages 
of  the  gastric  cavities,  into  which  air  had  acci- 
dentally been  introduced  during  the  removal 
of  the  animals  from  their  native  element. 
In  the  cirrigrada,  locomotion  is  effected 
Fig.  11. 


VelelLa  septentrionalis. 

*  In  the  tentacula  of  some  of  the  physograda, 
also,  a  similar  extensibility  exists.  The  lower  sur- 
face of  physalus,  for  instance,  which  itself  seldom 
exceeds  six  inches  in  length,  is  provided  with  ten- 
tacula sixteen  and  even  eighteen  feet  long. 


partly  by  the  movements  of  the  tentacules 
which  hang  down  from  the  inferior  surface; 
but  chiefly,  perhaps,  by  the  action  of  the  wind 
on  the  raised  crest,  with  which  most  of  these 
animals  are  provided.  Immediately  around 
the  mouth  are  placed  numerous  small  tubular 
suckers,  similar  to  the  feet  of  many  echinoder- 
mata.  Exterior  to  these  there  are  longer  tenta- 
cula, for  the  most  part  in  a  single  row,  and 
simple ;  sometimes  branched.  Neither  of  these 
two  kinds  of  organs  is  very  extensile.  The 
disc  from  which  the  tentacules  hang,  and  the 
crest,  are  supported  internally  by  a  calcareous 
plate,  which  is  the  only  organ  of  the  kind  in 
the  whole  class  of  acalephse.  It  somewhat  re- 
sembles in  structure  the  calcareous  axis  of 
retepora,  being  cellular  and  porous.  Its  nu- 
merous cells  are  filled  with  air,  which  renders 
the  whole  animal  so  buoyant  that  it  floats  on  the 
surface  of  the  water,  and  is  wafted  along  by  the 
winds.  In  velella  (Fig.  11.)  there  are  two 
plates,  one  placed  horizontally,  the  other  perpen- 
dicularly upon  the  upper  surface  of  the  former. 
They  are  marked  with  lines  of  growth,  enlarg- 
ing from  within  outwards,  like  the  extravascular 
shells  of  the  inollusca.  The  perpendicular 
plate  in  velella  supports  the  crest,  which  stands 
upright,  and  exposes  a  large  surface  to  the  wind. 
Rataria  (Fig.  12.)  has  its  crest  provided  with 
strong  muscular  bands  run-  p. 

ning  perpendicularly.  It 
lies  on  the  surface  of  the 
water,  with  the  crest  stretch- 
ed out,  so  that  its  whole  side 
touches  the  water.  When 
it  is  alarmed,  the  crest  is 
suddenly  contracted,  and  the 
centre  of  gravity  is  so  al- 
tered in  consequence,  that 
the  position  of  the  body  is  almost  reversed. 
When  the  crest  is  again  raised,  the  body  imme- 
diately resumes  its  former  position. 

Porpita  has  a  simple  plate  supporting  its  disc, 
without  any  crest,  and  long  tentacula,  which  are 
so  delicate  as  scarcely  to  bear  the  slightest  touch 
when  the  animal  is  taken  out  of  the  water.  When 
the  position  of  the  animal  is  altered  by  the  hand, 
so  as  to  make  the  surface  covered  with  suckers 
the  upper  one,  all  the  tentacula  of  one  half  of 
the  body  turn  round  to  the  dorsal  surface,  and 
all  those  of  the  other  half  stretch  over  their 
own  surface,  and  thus  the  animal  very  soon 
regains  its  old  position. 

II.  Motility  and  Sensation.  —  Almost  all 
observers  have  failed  to  discover  anything  re- 
sembling a  nervous  system  in  the  Acalephae. 
Even  Eschscholtz,*  who  devoted  so  much  atten- 
tion to  their  anatomy,  could  not  see  nerves  in 
the  largest  that  he  examined.  But  in  Cydippe, 
according  to  Dr.  Grant,f  there  is  a  structure 
which  can  be  regarded  only  as  belonging  to 
the  nervous  system.  It  consists  of  a  double 
transverse  filament  of  a  milky  white  colour, 
running  round  the  body,  near  its  surface,  at  a 
short  distance  above  the  mouth.  The  two 
cords  of  which  this  filament  is  composed  unite 
in  the  middle  of  each  of  the  spaces  between 

*  System,  p.  19. 

t  Trans.  Zool.  Soc.  of  Loud.  i.  10. 


Rataria  cordata. 


ACALEPII7E. 


41 


the  ciliated  arches  to  form  eight  ganglia,  from 
each  of  which  two  nerves  go  to  the  adjoining 
bands,  and  one,  larger  than  the  others,  runs 
upwards  in  the  middle  of  the  transparent  space 
between  the  bands,  and  can  be  traced  to  be- 
yond the  middle  of  the  body.  In  the  course 
of  these  last-mentioned  nerves,  two  or  three 
smaller  ganglia  are  visible,  from  which  fila- 
ments pass  inwards  to  the  viscera.  Dr.  Grant 
likens  these  nerves  and  filaments  to  the  abdo- 
minal nerves  of  pectinaria  and  other  transpa- 
rent animals. 

The  circular  fibres  forming  the  sphincters  of 
the  orifices  of  the  air-bladder  in  physalus  have 
been  mistaken  for  nerves.* 

There  is  no  evidence  that  the  acalephse  possess 
any  other  sense  than  that  of  touch.  But,  al- 
though they  cannot  be  said  to  have  the  sense  of 
sight,  they  are  evidently  affected  by  light.  At 
least  some  of  the  smaller  tribes  shun  a  bright 
light,  and  sink  into  the  deep  to  escape  from  it. 

In  most  of  the  tribes  of  acalephse,  the  sense 
of  touch  seems  to  have  its  seat  chiefly  in  the 
tentacula  and  cirri,  with  which  almost  all  are 
provided.  The  degree  of  sensitiveness  with 
which  these  are  endowed  varies  much.  In 
some,  the  slightest  touch,  even  agitation  of  the 
water,  is  sufficient  to  excite  them  to  contrac- 
tion. These  organs  of  touch,  as  has  been  al- 
ready mentioned,  are  subservient  chiefly  to  the 
nutritive  functions.  Other  parts  of  the  bodies 
of  most  acalephae  also  manifest,  by  their  con- 
tractions, a  certain  degree  of  sensitiveness. 
Several  of  the  ciliograda  alter  the  shape  of 
their  general  mass  when  touched.  In  physalus 
the  crest  appears  to  be  more  sensitive  than  any 
other  part.  Many  species,  particularly  of  the 
pulmograda,  give  no  signs  of  their  feeling  even 
the  deepest  and  most  extensive  wounds  of  their 
discs.  But  it  was  observed  by  Spallanzani, 
that,  by  friction,  and  by  punctures  of  the  mus- 
cular membrane  of  the  disc,  the  movements  of 
contraction  and  dilatation  could  be  excited  in 
medusae,  which,  having  been  kept  in  a  dry 
place  during  twenty-four  hours,  had  discon- 
tinued their  ordinary  motions,  and  had  lost 
nearly  two-thirds  of  their  bulk  by  the  running 
out  of  their  contained  fluids.f 


*  Isis.  Nov.  1819. 

t  Professor  Ehrenberg  has  very  recently  attempted 
to  shew  that  medusa  aurita  is  possessed  of  eyes,  in 
the  form  of  minute  red  points,  which  are  seen  on 
the  surface  of  the  eight  brown-coloured  masses  set 
round  the  circumference  of  the  disc.  These  masses, 
according  to  his  observations,  consist  each  of  a  yel- 
lowish, oval,  or  cylindrical  little  body,  which  is  at- 
tached to  a  small  and  delicate  pedicle.  This  short 
pedicle  arises  from  a  vesicle,  in  which  there  is 
placed  a  glandular  body,  unattached,  presenting  a 
yellow  colour  when  viewed  with  transmitted 
light,  a  white  colour  under  reflected  light.  It 
is  upon  the  dorsal  aspect  of  the  yellow  head, 
which  surmounts  the  pedicle,  that  the  well  denned 
red  point  is  seen,  which  Ehrenberg  considers  as  an 
eye.  HP.  compares  the  eyes  of  medusa  to  those  of 
some  rotifera  and  entomostraca.  The  glandular  body 
situated  at  the  base  of  the  pedicle,  he  regards  as  an 
optic  ganglion,  which,  he  seems  to  have  satisfied 
himself,  is  connected  with  two  filaments  that  decus- 
sate one  another  at  about  the  middle  of  their  course. 
These  he  describes  as  forming  part  of  a  nervous 


III.  Digestion. —  The  structure  and  action 
of  the  organs  concerned  in  the  function  of 
digestion  in  the  acalephse  are  still  involved  in 
much  obscurity.  Even  in  the  large  and  fre- 
quently examined  physalus,  it  is  difficult  to 
ascertain  the  functions  of  the  various  parts  in 
a  satisfactory  manner ;  and,  accordingly,  there 
exists  so  much  difference  of  opinion  amongst 
anatomists  with  regard  to  them,  that  some  will 
not  even  admit  that  it  has  a  mouth,  while 
others  assign  to  it  both  a  mouth  and  an  anus, 
as  well  as  ccecal  prolongations  of  the  stomach. 
Eschscholtz  concluded,  from  his  numerous  ob- 
servations on  the  living  animals,  that,  in  all  the 
physograda,  the  digestive  organs  consist  merely 
of  absorbing  tubes  or  suckers,  all  of  which 
are  simple,  and  pendent  from  the  inferior  sur- 
face. He  seemed  to  think  that  the  action  of 
these  filamentary  organs  was  analogous  to  that 
of  the  roots  of  plants; — that  they  were  en- 
dowed with  an  endosmosic  power,  which  en- 
abled them  to  imbibe  nutritious  matter  from 
the  water.  However  this  may  be  with  regard 
to  the  simple  filaments,  or  cirri,  it  appears  pro- 
bable that  the  suckers  are  provided  with  orifices 
at  their  extremities,  through  which  proper  ali- 
mentary matter  passes  into  the  interior;  for 
several  observers  agree  in  stating,  that  both  the 
physograda,  and  the  diphyda  apply  their 
suckers  to  the  bodies  of  other  animals,  and  re- 
main adherent  to  them  for  some  time,  during 
which  they  seem  to  take  up  some  nourishing 
matter.  Eudoxia  has  only  one  sucker.  Messrs. 
Quoy  and  Gaimard  have  described  in  detail 
the  singular  filamentary  organ  which  bears 
these  suckers  in  diphyes.  Generally  it  is  seen, 
at  first,  only  as  a  shapeless  opaque  mass,  of  a 
reddish  colour,  lying  contracted  within  the 
swimming  cavity.  But,  gradually,  it  is  ex- 
tended, and  then  there  are  perceptible,  along 
the  whole  of  one  side  of  a  fine  transparent  tube, 
numerous  suckers,  of  a  lengthened  form  ;  each 
is  covered  by  a  very  delicate  bell-shaped  case, 
and  has  its  base  surrounded  by  groups  of  mi- 
nute vesicles,  which  are,  probably,  the  ovaries. 
From  the  base  there  arises  also  a  little  tenta- 
cule  or  filament,  susceptible  of  very  great 
elongation,  and  which  sends  off  many  secon- 
dary filaments.* 

The  digestive  organs  of  the  ciliograda  are 
less  dubious.  In  these  we  find  uniformly  a 
straight  alimentary  canal  with  two  orifices,  the 
mouth  inferior,  the  anus  superior,  in  the  ordi- 
nary position  of  the  animal.  In  some  species 
there  are  lips  formed  by  short  and  broad  folds 
of  the  integument,  four  in  number,  and  very 
sensitive.  In  cydippe,  Dr.  Grant  found  these 
lips  capable  of  rapid  extension  and  retraction. 

circle  placed,  throughout  the  greater  part  of  its 
course,  immediately  along  the  bases  of  the  row  of 
tentacules  that  surround  the  disc,  so  as  to  form,  as 
it  were,  the  outer  wall  of  the  circular  vessel,  or  ap- 
pendage of  the  intestinal  cavity,  which  runs  round 
the  margin  of  the  disc.  The  same  observer  de- 
scribes another  nervous  circle,  composed  of  four 
ganglion-like  masses,  disposed  around  the  mouth, 
each  being  in  connexion  with  a  corresponding  group 
of  tentacules.  (Ehrenberg,  in  Miillcr's  Archiv 
fur  Anat.  Physiol.,  &c.  1834.  p.  562.) 
*  Ann.  des  Sc.  Nat.  x.  8. 


42 


ACALEPH^E. 


The  mouth  is  large,  the  oesophagus  straight  and 
wide ;  the  stomach  is,  for  the  most  part,  of  an 
ovate  form,  the  intestine  passes  in  a  straight 
line,  and  with  a  uniform  diameter,  to  its  ex- 
tremity. The  anus  has  a  prominent  circular 
margin  in  cydippe.  No  absorbent  vessels  can 
be  seen  arising  from  the  gastric  cavity.  In 
many  species,  the  alimentary  canal  is  so  large 
as  to  occupy  the  greater  part  of  the  interior  of 
the  body.  When  there  is  no  food  within  it,  it 
remains  open  at  both  extremities,  and,  as  the 
animal  swims  generally  with  its  mouth  fore- 
most, there  is  a  current  of  water  continually 
passing  through  it.  Eschscholtz  observed,  that 
when  suitable  aliment  was  carried  by  this  cur- 
rent against  the  walls  of  the  stomach,  the 
orifices  were  immediately  contracted,  and  the 
digestive  process  begun.  Minute  Crustacea, 
salpae,  &c.,  have  been  found  in  the  stomachs 
of  ciliograda.  The  diligent  observer  just  men- 
tioned seemed  to  regard  the  canal  leading  from 
the  stomach  to  the  dorsal  surface,  (which  we 
have  called  the  intestine,)  as  forming  no  part  of 
the  digestive  organs.  He  termed  it  "  the 
water-canal,"  and  considered  it  as  connected 
merely  with  the  peculiar  mode  of  locomotion, 
inasmuch  as  he  observed  it  so  patent  while  the 
animal  was  swimming  and  not  digesting  as  to 
admit  of  a  free  passage  for  the  water ;  which, 
otherwise,  in  entering  the  open  mouth,  would 
have  much  impeded  progressive  motion. 

It  was  generally  believed,  until  within  a  very 
recent  period,  that  some  of  the  pulmograda 
were  destitute  of  stomachs.  Hence  the  term 
of  agastric  medusa  which  was  applied  to  them 
by  Peron.  The  researches  of  Dr.  Milne  Ed- 
wards, however,  have  rendered  it  probable  that 
this  supposition  was  erroneous,  and  founded 
on  inaccurate  observations.  We  have  now  rea- 
son to  believe  that  all  the  pulmograda  have 
gastric  cavities ;  but  all  have  not  true  mouths. 
There  are  some  in  which  the  only  communica- 
tion between  the  stomach  and  the  outer  surface 
is  through  numerous  ramified  canals  in  the 
pendent  arms,  which  open  externally  by  ex- 
tremely minute  orifices,  barely  sufficient,  even 
in  large  species,  to  admit  the  smaller  ento- 
mostraca.  Such  a  structure  exists  in  rhizostoma. 
By  injecting  milk  into  its  gastric  cavity,  the 
canals  in  its  arms,  and  their  oscules  can  be 
rendered  visible;  and  it  is  then  discovered 
that  from  the  minute  oscules,  which  are  situ- 
ated in  indentations  along  the  margins  of  the 
arms,  small  vessels  proceed  inwards,  and, 
uniting  in  twos  and  threes  together,  open  into 
one  large  canal  which  runs  through  the  middle 
of  each  arm.  These  arms  are  large,  fleshy, 
foliated  organs,  eight  in  number;  each  of  which 
has  a  triangular  shape.  The  eight  canals  above 
mentioned  unite  two  and  two,  so  as  to  form 
four  great  trunks,  which  open  into  a  large 
central  cavity, — the  only  one  in  the  body. 
This  cavity  is  situated  at  the  base  of  the  central 
process  pendent  from  the  lower  surface  of  the 
disc.  The  base,  in  rising  upwards,  enlarges 
into  four  fleshy  columns,  which  lose  them- 
selves in  the  disc.  It  is  between  these  four 
fleshy  columns  that  the  cavity  of  the  stomach  is 
placed.  The  intervals  between  the-  columns 


would  form  so  many  openings  into  this  cavity 
were  they  not  closed  by  a  fine  and  plaited 
membrane,  which  bulges  outwards  when  the 
stomach  is  filled.  From  the  circumference  of 
the  stomach,  at  equal  distances,  sixteen  vessels 
arise,  and  run  directly  towards  the  margin  of  the 
disc.  These  vessels  may  be  regarded  as  arteries, 
and  will  be  hereafter  described  along  with  other 
structures  more  nearly  resembling  the  parts  of 
a  circulating  system.  But  Cuvier*  was  disposed 
to  consider  them  as  cceca;  although  he  ad- 
mitted that  he  could  discover  no  other  vessels 
fitted  to  discharge  the  functions  of  arteries. 
He  remarked  that  if  we  regard  them  as  arteries, 
we  must  look  upon  the  little  vessels  which  lead 
from  the  appendages  or  arms  to  the  central 
cavity,  as  veins,  or  as  lymphatics;  and  then 
we  might  say  that  the  sea  is  as  a  stomach 
to  the  r/tizostoma,  in  the  same  way  as  the 
earth  acts  as  a  stomach  for  plants.  But,  at  all 
events,  Cuvier  was  convinced  by  his  dis- 
sections that  alimentary  matter  enters  the  body 
through  the  marginal  oscules  of  the  arms, 
and  that  it  is  accumulated  in  the  internal  cavity 
before  passing  into  the  radiating  vessels. 
By  experiments  on  the  living  animal,  Dr. 
Milne  Edwards  has  recently  provedf  that  the 
circumambient  fluid  and  its  contents  of  mi- 
nute size  do  really  enter  the  body  of  the 
rhizostoma  through  the  margins  of  the  arms. 
He  placed  a  living  rhizostoma  in  sea-water, 
artificially  coloured  red.  The  animal  did  not 
appear  to  suffer  from  the  presence  of  the 
colouring  matter.  Within  a  very  short  time, 
the  puckered  membrane  which  borders  the 
arms  was  distinctly  tinged  red,  and,  gradually, 
the  colour  ascended,  until  the  whole  body 
assumed  the  same  tint.  Dr.  Edwards  does  not 
state,  however,  whether  he  traced  the  progress 
of  the  coloured  fluid  through  the  brachial 
canals  and  the  vascular  system.  On  placing 
the  same  individual  again  in  pure  sea-water, 
the  colouring  matter  which  had  been  absorbed 
disappeared  gradually,  and  it  seemed  to  Dr.E. 
that  it  was  thrown  out  chiefly  from  the  brachial 
fringes,  but  partly  also  from  the  margin  of  the 
disc,  and  from  the  capillary  orifices  situated  at 
the  extremities  of  the  arms.  Dr.  Edwards 
satisfied  himself  that  it  is  impossible  for  ani- 
mals larger  than  small  animalcules  to  enter  the 
central  cavity  of  the  rhizostoma.  But  most  of 
the  pulmograda  have  large  central  mouths, 
either  simple  and  sessile,  or  placed  at  the  ex- 
tremity of  a  projection  from  the  lower  surface 
of  the  disc.  In  some,  the  mouth  is  more  or 
less  patent,  but  capable  of  being  closed  by  the 
approximation  of  the  base  of  the  arms.  In 
others  it  is  surrounded  by  a  ring  of  conside- 
rable density,  in  which  muscular  fibres  can  be 
distinctly  seen.  In  medusa  aurita,  there  are, 
just  within  the  cavity  of  the  mouth,  four  open- 
ings, which  lead,  by  as  many  short  but  wide 
canals,  into  four  spherical  sacs  of  considerable 
size.  These  are  completely  separated  from 
one  another  by  membranous  partitions.  That 
they  are  stomachs  is  proved  by  the  circum- 

*  Journ.  de  Phys.  xlix.  438 

t  Ann.  des  Sc.  Nat.  xxviii.  24U. 


ACALEPIIJE. 


43 


stance  of  fishes  being  found  in  them.*  From 
each  sac,  four  vessels  arise,  which  run  out- 
wards to  the  circumference  of  the  animal. 
Other  species  (e.  g.  medusa  cup'dtuta)  have  the 
four  gastric  sacs  in  free  communication  with 
one  another  ;  and,  frequently,  (e.  g.  in  pelagia, 
(•///•y.sy/o/v/,  and  teginu,)  in  connexion  with  these, 
there  are  four  other  sacs,  lined  with  a  more 
dense  membrane  than  the  former.  These  gas- 
tric appendages  have  the  form  of  simple  canals 
in  equorea  and  tima  ;  and  of  branched  vessels 
in  medusa  and  st/ienonia. 

They  were  chiefly  such  pulmograda  as  have 
their  disc  bell-shaped  that  were  formerly  sup- 
posed to  be  ugustric.  It  was  imagined  that 
alimentary  matter  being  received  within  the 
campanulate  depression,  its  orifice  was  con- 
tracted, and  nourishment  taken  up  by  im- 
bibition through  the  walls  of  the  disc.  But 
an  attentive  examination  of  Cari/bdca  mar- 
supialis,  (Peron,)  one  of  the  animals  which  was 
believed  to  beagastric,  has  satisfied  Dr.  Milne 
Edwards  that  a  mouth  and  an  internal  cavity 
connected  with  it  do  really  exist.  The  great 
transparency  of  this  animal  renders  the  dis- 
covery of  its  internal  structure  a  matter  of  con- 
siderable difficulty,  excepting  when  coloured 
injections  are  used.  Dr.  Edwards  found  within 
the  funnel-shaped  cavity  of  Carybdea,  and,  as 
it  were,  pendent  from  its  roof,  a  projection  of 
very  delicate  tissues,  evidently  forming  tenta- 
cula  surrounding  a  central  mouth,  and  a 
stomach,  from  which  proceed  four  long  canals 
leading  to  the  tapering  filaments  which  hang 
down  from  the  margin  of  the  body  of  the 
animal.  These  canals,  Dr.  Edwards  believes 
to  be  analogous  to  the  radiating  vessels  of 
rhizostoma.  There  exists  just  at  the  com- 
mencement of  each  canal,  and  opening  into  it, 
a  group  of  minute  cylindrical  sacs,  which  may 
be  regarded  as  biliary  organs .f  But  in  most 
of  the  pulmograda  these  organs  are  situated  on 
the  margin  of  the  disc.  Generally,  they  pre- 
sent the  appearance  of  glands,  being  distinctly 
granular  in  their  structure.  They  are  opaque, 
have  a  lengthened  form,  and  are  lodged  in 
little  depressions,  and  surrounded  by  cup- 
shaped  folds  of  the  external  integument.  They 
are  connected  with  the  gastric  appendages  by 
small  tubes.}; 

In  Aurelia  phosphorea,  (Lam.)  (Pelagia, 
Esch.)  which  formed  the  principal  subject  of 
Spallanzani's  observations  on  the  acalephae, 
there  are  four  groups  of  membranous  tubes, 
convoluted,  and  resembling  in  structure  the 
intestines  of  vertebrate  animals.  Although  he 
did  not  trace  their  connexions,  Spallanzani 
appears  to  have  regarded  them  as  truly  parts 
of  the  alimentary  canal.  He  observed  that 
they  exhibit  a  peristaltic  motion,  both  in  the 
water  and  in  air,  which  can  be  increased  by 
the  application  of  stimuli.§ 

The  food  of  the  pulmograda  consists  of 
various  marine  animals — small  fishes,  mollusks, 

*  Gaede,  Beytrage  zur  Anat.  und  Phys.  der 
Medusen. 

t  Ann.  dcs  Sciences  Nat.  xxviii.  251. 
J  Eschscholtz,  op.  cit. 
§  Travels,  iv.  228. 


crabs,  and  worms.  Even  large  fishes  are  some- 
times found  entangled  amongst  the  arms  and 
tentacules.  They  are  probably  killed  by  the 
peculiar  excretion  which  covers  the  surface  of 
these  organs,  and  which  produces  a  stinging 
effect  on  man.  The  long  filamentary  appen- 
dages which  hang  from  the  margins  of  the  disc 
in  Carybdea  rxnd  others,  are  covered  with  a 
glutinous  matter  to  which  passing  objects  ad- 
here ;  the  animal  has  the  power  of  stretching 
them  out  and  withdrawing  them  at  pleasure, 
and  of  so  folding  them  inwards  as  to  carry  to 
the  mouth  whatever  may  be  attached  to  their 
sides.  It  would  appear  that  some  species  are 
endowed  with  the  power  of  discriminating  the 
food  most  suitable  to  their  own  nature.  Gaede 
remarks  that  he  has  never  found  fishes  in  the 
stomach  of  medusa  capillata,  but  often  worms ; 
while  in  that  of  medusa  aurita  there  are  fre- 
quently fishes,  rarely  worms.  In  none  of  the 
pulmograda  have  either  masticatory  or  salivary 
organs  been  discovered. 

The  cirrigrada  have,  in  the  middle  of  their 
lower  surface,  a  large  flask-shaped  stomach, 
the  mouth  of  which  is  formed  like  a  sucker. 
There  appears  to  be  a  communication  between 
this  organ  and  the  numerous  tentacula  which 
surround  the  mouth,  through  minute  canals. 
The  food  consists  of  small  animals,  such  as 
entomostracous  Crustacea;  the  undigested  re- 
mains of  which  are  again  ejected  through  the 
mouth. 

IV.  Circulation. — No  distinct  circulating 
system  has  hitherto  been  discovered  in  the 
acalephae.  But  perhaps  the  peculiar  apparatus 
of  radiating  vessels  connected  with  the  gastric 
cavities  in  the  pulmograda,  and  the  aquiferous 
canals  of  the  ciliograda,  which  seem  to  per- 
form nearly  the  same  functions  as  the  vascular 
system  of  higher  animals,  may  be  conveniently 
and  properly  considered  under  this  head. 

In  the  physograda,  Eschscholtz  saw  what  he 
considered  as  the  rudiments  of  a  circulatipn  ; 
namely,  distinct  vessels  arising  from  the  roots 
of  the  tentacula,  and  ramifying  on  the  in- 
ternal surface  of  the  air-bladders ;  but  it  does 
not  appear  that  he  traced  these  further,  or  that 
he  saw  the  movements  of  a  fluid  within  them. 

The  vessels  in  the  ciliograda,  within  which 
a  fluid  is  seen  to  move,  are  situated  chiefly 
beneath  the  cilia-bearing  arches.  This  fluid  is 
supposed  by  most  modern  anatomists  to  be 
merely  water ;  but  by  some  it  is  regarded  as  a 
peculiar  fluid,  the  product  of  the  animal's 
digestive  powers.  If  it  be  water  only,  the 
canals  in  which  it  moves  must  be  considered 
as  being  analogous  to  those  of  the  aquiferous 
system  of  other  classes  of  invertebrate  animals, 
which  has  been  so  fully  illustrated  by  the  re- 
searches of  Delle  Chiaje,*  and  which  is  pre- 
sumed to  be  subservient  to  the  respiratory 
function.  The  vessels  in  question  arise  in 
Beroe  from  a  vascular  circle  which  surrounds 
the  intestine  near  the  anus.  They  are  eight  in 
number,  and  one  runs  beneath  each  cilia-bear- 
ing arch,  from  one  extremity  of  the  body  to 

*  Mem.  sur   la  Storia  e  notomia  degli  animali 
senza  Vertebre,  4to.  Napoli,  1823-25. 


44 


ACALEPHjE. 


the  other.  They  then  terminate  in  another 
annular  vessel,  which  surrounds  the  mouth. 
In  their  course  they  give  off  numerous 
branches.  From  the  oral  circle  of  vascular 
structure  arise  two  large  vessels,  which  run 
along  the  walls  of  the  gastric  cavity,  and  ap- 
pear to  unite  with  the  other  circle  at  the  anal 
extremity.  These  last  Eschscholtz  regarded  as 
veins,  and  the  eight  external  vessels  as  arteries. 
He  supposed  that  the  veins,  passing  along 
the  walls  of  the  stomach,  absorbed  the  nutri- 
ment, and  then  carried  the  circulating  fluid  to 
the  cilia  for  aeration.  In  the  course  of  his 
observations  on  the  Beroe  ovatus,  Dr.  Fleming* 
distinctly  saw  a  fluid  moving  "  backwards  and 
forwards"  in  the  external  vessels ;  and  he  states 
that  "  while  the  animal  was  active,  there  were 
numerous  small  spaces  in  the  different  vessels 
where  the  contained  fluid  circulated  in  eddies." 
Dr.  Fleming  failed  to  detect  any  structure  in 
the  vessels  which  could  produce  these  partial 
motions.  In  cestum  naiadis,  Eschscholt/  thought 
that  he  saw  the  system  of  vessels  more  dis- 
tinctly than  in  any  other  of  the  acalephae.  He 
thus  described  it :  "  From  the  base  of  each  of 
the  two  tentacules,  a  vessel  takes  its  rise,  and 
goes  towards  the  bottom  of  the  stomach.  Here 
the  two  vessels  unite,  and  form  a  little  vascular 
circle  around  the  water-canal  (intestine).  From 
the  upper  margin  of  this  circle,  four  straight 
vessels  arise,  which  go  towards  the  two  rows  of 
cilia-bearing  organs  placed  on  the  dorsal  sur- 
face. Under  these  they  run,  two  in  one  di- 
rection, and  two  in  the  other.  At  either 
extremity  of  the  body,  these  unite  with  certain 
vessels  running  superficially  along  the  sides, 
and  which  complete  the  circulation  by  entering 
the  first  set  of  vessels  just  before  they 'begin  to 
run  beneath  the  ciliated  organs.  All  these 
vessels  are  simple  canals,  of  the  same  diameter 
throughout,  without  any  visible  branches.  They 
contain  a  colourless  watery  fluid,  in  which  mi- 
nute yellowish  globules  are  seen  to  move.  In 
the  vessels  which  arise  from  the  bases  of  the 
tentacules,  the  globules  mount  upwards  ;  they 
assume  a  rotatory  motion  in  the  vascular  circle; 
and,  in  the  four  dorsal  vessels,  they  seem  to 
move,  some  in  one  direction,  others  in  the  other. 
It  is  probable  that  what  appears  to  the  eye  as 
one  vessel,  is,  in  reality,  composed  of  two 
vessels,  running  parallel  and  close  together."f 

Seeing  that  the  radiating  vessels  which  arise 
from  the  gastric  cavities  of  the  pulmograda 
seem  to  carry  out  the  nourishing  material  to  all 
parts  of  the  body,  and  that  they  are,  in  some 
species  at  least,  connected  with  other  vessels 
which  form  a  complete  circle,  we  are  disposed 
to  class  them  under  this  head  along  with  the 
vascular  structures  already  described.  The 
exact  analogies  of  their  functions,  however, 
have  not  yet,  we  conceive,  been  distinctly 
made  out. 

From  the  stomach  of  rhizostoma,  formerly 
described,  sixteen  vessels  arise,  and  pursue  a 
straight  course  outwards  to  the  margin  of  the 
disc,  near  which  they  all  enter,  at  equal  dis- 

*  Mem.  Wcrn.  Soc.  iii.  401. 
t  Op.  cit.  p.  14. 


tances,  a  circular  vessel,  which  passes  com- 
pletely round  the  circumference  of  the  animal. 
Four  of  the  radiating  vessels  correspond  with 
the  four  fleshy  pillars  of  the  process  supporting 
the  arms,  and  there  exists  on  the  internal  sur- 
face of  each  of  these  pillars,  a  groove,  which 
establishes  a  direct  communication  between  the 
corresponding  vessel,  and  one  of  the  large 
vessels  of  the  central  process.  The  other 
twelve  are  distributed  by  threes  in  the  intervals 
between  the  first  four,  and  arise  from  those 
parts  of  the  stomach  which  are  closed  by  the 
plaited  membranes.  The  space  intervening 
between  the  circular  vessel  and  the  margin  of 
the  disc  is  occupied  by  an  innumerable  multi- 
tude of  little  vessels  which  form  a  net-work 
like  the  finest  lace.*  In  medusa  aurita,  there 
are  also  sixteen  radiating  vessels,  four  of  which 
arise  from  each  of  the  four  sacs,  into  which  the 
gastric  cavity  in  this  species  is  divided.  Two 
of  the  four  vessels  in  each  group  are  simple, 
the  other  two  are  several  times  bifurcated ; 
both  the  simple  main  trunks  and  all  the 
branches  so  formed,  enter  a  circular  vessel  sur- 
rounding the  disc,  which  seems  to  be  connected 
also  with  the  tubular  cavities  of  the  numerous 
cilia  which  surround  the  margin  like  a  fringe, 
and  which  are  capable  of  elongation  and  con- 
traction.-f-  Carus  remarks  with  regard  to  the 
circular  vessel,  that "  it  may  be  considered  as 
an  extremely  simple  rudiment  of  the  great  cir- 
culation of  superior  animals,  in  case  we  view 
the  radiating  as  chyliferous  vessels.''^ 

V.  Respiration. — It  is  probable  that  the  air- 
bladders  of  the  physograda,  the  swimming 
organs  of  the  diphyda,  and  the  cilia  of  the 
ciliograda  are  all  subservient,  in  a  greater  or 
less  degree,  to  the  respiratory  function,  as  well 
as  to  locomotion.  The  vessels  in  the  last  men- 
tioned class,  which  have  been  described  above 
as  appertaining  to  the  circulating  system,  are 
regarded  by  some  as  respiratory  organs ;  and 
by  Lamarck  were  compared  to  the  tracheae  of 
insects.  They  have  been  called  aquiferous 
trachea.  Those  who  consider  them  in  this 
light  believe  that  they  are  open  at  two  points, 
so  as  to  admit  the  circumambient  fluid  to  pass 
freely  through  them.  The  most  recent  and 
accurate  observations,  however,  leave  it  doubt- 
ful whether  this  really  takes  place  in  the 
ciliograde  acalephae. 

With  regard  to  the  pulmograda,  several 
parts  and  organs  have  been  pointed  out  by 
different  observers  as  being,  in  all  probability, 
the  seats  of  the  respiratory  function.  Cuvier 
thought  that  the  delicate  plaited  membranes 
which  exist  between  the  fleshy  pillars  of  the 
central  process  in  rhizostoma,  and  which  form 
in  part  the  walls  of  the  stomach,  might  be  re- 
garded as  the  organs  of  respirarion.  Eisenhardt 
supposed  that  he  saw  them  in  certain  tentacu- 
lated processes  attached  to  the  membranous 
partitions  which  divide  the  gastric  sacs  of  some 
species  from  one  another  ;  while  Gaede  looked 
upon  the  four  small  sacs  which  overlie  the 

*  Cuvier,  Journ.  de  Phys.  xlix.  433. 

t  Gaede,  Anat.  der  Medusen. 

$  Carus,  Comp.  Anat.  (by  Gore,)  ii.  266. 


ACALEPH^E. 


45 


gastric  cavities  in  medusa  aurita  as  subser- 
vient to  the  same  function.  These  sacs  com- 
municate directly  with  the  gastric  cavities  by 
means  of  openings  in  the  membranous  par- 
titions which  separate  them.  The  partitions 
bear  on  their  inferior  surfaces,  plaited  mem- 
branes, which,  under  the  microscope,  present 
the  appearance  of  being  studded  with  vesicles 
containing  a  little  watery  fluid.  A  row  of 
filamentary  organs  is  also  attached  to  these 
membranes,  which  move  like  external  cilia, 
even  for  some  time  after  they  have  been  re- 
moved from  the  body  of  the  animal. 

VI.  Secretion. — The  existence  of  this  func- 
tion in  the  acalephae  is  made  known  to  us  by 
the  emission  from  their  bodies,  under  certain 
circumstances,  of  a  glairy  mucus ;  by  the 
stinging  effect  which  some  unknown  product 
of  their  organization  has  upon  our  skin;  and 
by  the  remarkable  phenomenon  of  luminousness, 
which  a  large  number  of  them  present.  The 
organs  by  which  the  mucus  is  secreted  have 
not  been  satisfactorily  observed.  Dr.  Milne 
Edwards  saw  reason  to  conclude  with  regard 
to  the  rhizostoma,  that  a  large  quantity  of  this 
fluid  is  secreted  by  a  glandular  structure 
situated  along  the  margins  of  the  arms.  The 
stinging  property  possessed  by  several  animals 
of  this  class  has  been  the  subject  of  inquiry 
since  the  time  of  Aristotle,  but  to  this  day 
we  remain  in  doubt  with  regard  to  the  nature 
and  mode  of  production  of  the  agent  which 
causes  this  effect.  Some  men  seem  to  be  in- 
sensible to  the  irritation  generally  produced  by 
the  contact  of  living  acalephae.  But,  for  the 
most  part,  a  slight  touch  of  any  part  of  their 
surface,  and  chieHy  of  the  pendent  tentacula, 
is  followed  within  a  few  minutes,  at  most,  by 
a  burning  pain,  redness,  swelling,  and  some- 
times even  a  vesication,  of  all  that  portion  of 
the  skin  which  touched  the  animal.  Sloane 
said  of  the  physalus,  ("  what  the  seamen  call 
caravels,  or  Portuguese  men-of-war/')  "  They 
burn  violently — they  do  suck  themselves  so 
close  to  the  skin  that  they  raise  blisters,  and 
cause  sometimes  St.  Antony's  fire."*  Even  on 
our  own  coasts,  severe  cases  of  inflammation 
of  the  skin  are  occasionally  seen,  which  have 
been  produced  by  the  irritation  received  during 
bathing  from  some  of  the  larger  pulmograda. 
In  physalus,  the  stinging  property  seems  to 
reside  chiefly  in  the  fluid  with  which  the  ten- 
tacula are  filled.  It  continues  to  act  power- 
fully even  after  the  organs  containing  it  have 
been  detached  from  the  body.  And  not  only 
so,  but  it  is  said  by  some  observers  that  its 
peculiar  properties  are  so  permanent,  that 
vessels  in  which  the  animals  have  been  placed 
must  be  washed  several  times  in  water,  and 
carefully  scoured  before  they  can  be  used 
without  inconvenience.  On  one  occasion  it 
was  found  that  linen,  which  had  been  merely 
rinsed  in  soap  and  water,  had  this  quality  of 

*  Nat.  Hist,  of  Jamaica,  ii.  p.  273.  Sloane  re- 
commends acajou  oil  as  "  the  remedy  for  the  sting- 
ing of  this  nettle."  Mr.  Bennett  has  lately  found 
(Lond.  Med.  Gaz.  xiv.  908.)  that  the  application 
of  vinegar  to  the  irritated  surface  in  some  degree 
alleviates  the  pain. 


irritation  fifteen  days  after  it  had  been  used  in 
making  observations  on  the  physalus.*  None 
of  the  cirrigrada  hitherto  examined  possess 
the  stinging  property. 

The  organs  by  which  the  luminous  matter  is 
elaborated  are  unknown.  In  some  species,  it 
is  evidently  mixed  with  the  mucous  fluid, 
which  is  so  abundantly  poured  out  from  the 
margins  of  the  arms  and  the  disc.  It  has  been 
frequently  observed  that  the  ciliograda  are 
luminous  chiefly  along  their  rows  of  cilia,  and 
that  these  continue  to  emit  light  for  some  time 
after  their  removal  from  the  body.  Perhaps 
the  greater  number  of  the  acalephae  are  lumi- 
nous. According  to  Dr.  M'Culloch,  all 
inhabiting  the  British  seas  are  so ;  and 
indeed  it  is  chiefly  to  the  emission  of  light 
by  animals  of  this  class  that  the  beautiful 
phenomenon  of  the  luminousness  of  the  sea 
is  owing  in  all  situations.  Spallanzani, 
however,  whose  observations  and  experiments 
on  this  subject  were  as  extensive  as  they  were 
careful  and  ingenious,  came  to  the  conclusion 
that  "  the  medusae  which  are  possessed  of  lumi- 
nous properties  are  extremely  few  compared 
with  those  which  are  destitute  of  it."  The 
same  philosopher  remarked,  with  regard  to 
some  of  the  pulmograda,  that  they  emit  light 
more  strongly  during  the  contractions  of  their 
disc  than  at  other  times  ;  that  the  intensity  of 
their  light  increases  when  they  are  pressed  in 
any  way  ;  that  the  luminousness  resides  chiefly 
in  a  peculiar  fluid  secreted  by  glands  situated 
around  the  margins  of  the  disc,  along  the  edges 
of  the  tentacula,  and  in  the  fringed  partitions  of 
the  gastric  cavities ;  that  this  fluid  being  mixed 
with  other  fluids,  as  with  fresh  and  salt  water, 
and  especially  cow's  milk,  imparts  its  lumi- 
nousness to  them  ;  that  when  spread  over  solid 
bodies  it  continues  to  shine  for  several  minutes; 
and  that  in  it  there  generally  exists  that  irri- 
tating substance  which  produces  the  stinging 
effect.  Spallanzani  applied  some  of  this  fluid 
on  two  occasions  to  the  tip  of  his  tongue.  It 
excited  a  burning  sensation,  which  lasted  more 
than  a  day.  A  similar  feeling,  but  much  more 
painful,  followed  the  accidental  application  of  a 
singledrop  of  the  same  fluid  to  the  conjunctiva.f 
In  most  of  the  acalephae,  the  external  cover- 
ing is  very  fine,  smooth,  and  delicate;  but 
sometimes  it  is  granular,  or  even  warty.  It 
does  not  appear  that  these  differences  in  its 
structure  have  been  observed  by  any  naturalist 
to  be  connected  with  corresponding  differences 
in  the  power  of  emitting  light.  (See  LUMI- 
NOUSNESS, ANIMAL.) 

VII.  Generation. — The  organs  of  this  func- 
tion cannot  always  be  satisfactorily  ascertained. 
This  may,  in  a  great  measure,  be  owing  to  their 
minuteness  and  transparency  when  not  in 
action.  Ovaria  and  oviducts,  however,  are  dis- 
tinctly seen  in  several  species;  but  no  other 
organs  connected  with  the  generative  function 
have  hitherto  been  discovered.  According  to 
Eschscholtz,  the  ovaria  in  the  physograda  con- 
sist of  several  groups  of  vesicles  and  filaments, 

*  Journ.  Roy.  Inst.  1831,  p.  205. 
t  Travels  in  the  two  Sicilies,  iv.  250. 


46 


ACALEPII/E. 


Fig.  13. 


loosely  attached  to  the  lower  surface  of  the 
air-bladder.  In  the  diphyda,  they  are  in  the 
form  of  numerous  vesicles,  having  thick  tunics 
filled  with  an  opaque  white  fluid,  and  situated 
within  one  of  their  swimming  organs.  Such 
parts  were  seen  by  Eschscholtz  only  in  some 
individuals,  and  on  this  account  he  was  dis- 
posed to  regard  them  as  ovaries.  But  Messrs. 
Quoy  and  Gaimard  seem  to  consider  it  more 
probable  that  the  minute  botryoidal  bunches  of 
vesicles,  which  surround  the  base  of  each 
sucker  on  the  lengthened  filaments,  (before 
alluded  to  as  being  subservient  both  to  nutri- 
tion and  to  locomotion,)  are  the  ovaries.* 
It  does  not  appear  that 
either  Eschscholtz  or 
Messrs.  Quoy  and  Gai- 
mard saw  the  ova. 

In  the  ciliograda,  the 
ovaries  are  more  obvious. 
They  consist  of  two  or 
four  vesicular  organs, 
each  placed  between  two 
of  the  cilia-bearing  arches. 
In  cydippe,  they  are  of  a 
red  colour,  and  nearly  cy- 
lindrical shape.  The  ova 
are  spherical. 

The  parts  in  the  pul- 
mograda  corresponding  to 
the  organs  just  referred  to, 
are  eight  round  bodies,  of 
small  size,  situated   near 
the   margin  of  the    disc, 
each  formed  of  a  vesicle, 
containing,  at  its  free  ex- 
A  portion  of  the    treraity,     many     minute 
ovtgerous  filament     hexagonal      corpuscules  ; 
of    Diphyes  much     there  is  aUached  to  each 
magnified.  vesicle  a  digitated  appen- 

dix, which  seems  to  be  hollow,  and  to  com- 
municate with  the  circular  vessel.  These 
organs  were  seen  by  Gaede  and  by  Muller 
in  medusa  capillata,  and  M.  aurita,  and  by 
Eschscholtz  in  some  species  of  cyanea,  st/ie- 
nonia,  pelagia,  and  chrysaora  ;  Dr.  M.  Ed- 
wards has  observed  them  also,  at  certain 
seasons,  in  rhizosloma ;  and  in  carybdea  mar- 
supialis,  he  found,  midway  between  each 
pair  of  pendent  filaments,  and  immediately 
above  a  little  notch  in  the  margin,  four 
spots  of  a  deep  brown  colour,  each  of  which 
appeared,  under  the  microscope,  to  be  formed 
partly  by  a  minute  spherical  body,  having  a 
granular  aspect,  as  if  it  were  filled  with  eggs, 
and  partly  by  a  little  sac,  with  puckered  sides, 
which  is  imbedded  in  the  gelatinous  substance 
of  the  body.  These  he  regards  as  the  ovaries.f 
But,  notwithstanding  their  having  found  gra- 
nular bodies  like  ova  in  the  organs  above 
described,  neither  Gaede  nor  Muller  considered 
them  as  ovaries.  Muller  regarded  the  granules 
as  excrementitious  matters  ;  and  Gaede  thought 
that  he  saw  the  ovaries  in  the  plaited  mem- 
branes of  the  gastric  cavities;  whence  he 
observed  the  ova  descend  into  certain  minute 

*  Ann.  des  Sc.  Nat.  x.  8. 

t  Ann.  des  Sc.  Nat.  xxviii.  250. 


vesicles  imbedded  in  the  margins  of  the  arms- 
lie  remarked  that,  in  medusa  aurita,  when  the 
cells  in  the  arms  were  filled  with  eggs,  the 
plaited  membranes  had  none  :  and,  on  the  other 
hand,  when  there  were  no  eggs  in  the  arms,  the 
plaited  membranes  were  studded  with  them. 
Cuvier  was  also  of  opinion  that  the  ova  are 
formed  in  the  plaited  membranes  above  men- 
tioned, and  that  they  are  matured  in  the  mar- 
gins of  the  arms.* 

No  observations,  so  far  as  we  know,  have 
hitherto  been  made  on  the  development  of  the 
ova ;  but  Dr.  Grant  has  recently  stated  that  the 
ova  of  equorea  are  furnished  with  cilia,  and 
have  locomotive  powers,  like  the  ova  of  the 
porifera  and  polypifera.^  The  colours  of  the 
acalephse  often  depend  on  the  tints  of  their  ova: 
these  are  generally  red,  but  sometimes  brown, 
yellow,  or  purple. 

VIII.  Geographical  distribution. — We  con- 
ceive that  a  brief  notice  of  this  part  of  their 
natural  history  may,  in  some  measure,  illus- 
strate  the  physiology  of  the  acalephae.  They 
are  met  with  in  all  seas  ;  but  certain  families 
exist  more  abundantly  in  some  localities  than 
in  others.  The  ciliograda  and  pulmograda, 
for  instance,  are  inhabitants  chiefly  of  the  colder 
regions,  while  the  physograda  are  seldom 
found  beyond  the  limits  of  the  tropical  zone. 
Some  float  in  bays,  and  near  land,  but  the 
greater  number  in  the  high  seas.  Medusa:  and 
cyanea  are  met  with  only  in  the  cold  and  tem- 
perate zones  of  the  northern  hemisphere.  Cy- 
dippe lives  in  the  North  Arctic  Ocean,  as  well 
as  in  the  Pacific,  under  the  equator.  One  species 
of  cestum  inhabits  the  Mediterranean, — another 
the  South  Sea.  It  frequently  happens  that 
enormous  numbers  of  one  species  are  met  with 
closely  grouped  together,  so  as  somewhat  to 
impede  a  ship's  progress  for  two  or  three  suc- 
cessive days ;  after  which,  not  a  single  indi- 
vidual of  the  same  species  is  seen.  In  the 
European  seas,  it  is  chiefly  in  summer  and 
autumn  that  the  acalephae  swim  on  the  surface. 
In  winter,  they  probably  sink  to  the  bottom. 

BIBLIOGRAPHY. — Madeer,  Tentamen  systematis 
Medusarum  stabiliendi,  in  Nova  Acta  Aca  '.  Natur. 
curios,  vol.  viii.  Append,  p.  19  ;  and  Papers  in  the 
Svenska  Vetenskaps  nya  Handlingar  An.  1791, 
transl.  into  Germ.  s.  t.  Neue  Abb.  and.  der  Schwed. 
Akademie,  &c.  Jahr  1791  ;  Seite  75,  149,  227. 
Dana,  De  quibusdam  urticae  marinae  differentiis  : 
Miscel.  Societal.  Taurinens.  v.  iii.  p.  206.  Muller, 
Beschreibung  zweier  Medusen  :  Beschaeft.  der  Ber- 
liner Gesellsch.  Nalurfor.  Freunde  Bd.  2.  S.  290. 
Cuvier,  Sur  1'organization  de  quelques  Meduses  ; 
Societe  Philomat.  A.  3,  F.  2,  p.  69.  Strom,  A 

gaper  in  Danish  on  the  Medusa  palliata  in  the 
krifter  der  Kiobenhab.  Selskabs  nye  Saml.  Deel.  3, 
S.  250.  Swartx,  Medusa  pelagica  beskrifven : 
Svenska  Vetens.  Acad.  Hand.  A.  1791,  S.  188  in 
the  German  transl.  T.  1791,  S.  172.  Gaede,  Bey- 
traege  zur  Anatomic  und  Physiologie  der  Medusen, 
8vo.  Berl.  1816.  Quoy  et  Gaimard,  Zoologie  d'un 
Voyage  autonr  du  Monde,  2  vols.  4to.  Atlas  fol. 
Paris,  1824.  Duperrey,  Voyage  autour  du  Monde 
4to.  Atlas  fol.  Paris,  1826-1834. 

(John  Coldstream.) 


*  Regne  Animal,  second  edit.  iii.  277. 
Carus,  Comp.  Anat.  ii.  307. 
t  Lectures,  Lancet,  No.  565.  p.  483. 


See  also 


ACIDS,  ANIMAL.     AC11ITA. 


47 


ACIDS,  ANIMAL.  Several  acids  are 
found  in  animal  products,  some  of  which  are 
peculiar  to  organized  bodies,  and  others  com- 
mon to  them  and  to  the  other  kingdoms  in 
nature.  The  former  are  characterized  by  their 
analogy  to  other  organic  compounds,  and  are 
ternary  or  quaternary  combinations  of  carbon, 
hydrogen,  oxygen,  and  nitrogen.  The  latter 
are  for  the  most  part  binary  compounds,  such 
as  the  phosphoric,  carbonic,  muriatic,  sul- 
phuric, and  fluoric  acids. 

With  the  exception  of  lactic  acid,  the  exis- 
tence of  which  as  a  distinct  definite  compound 
is  doubtful,  there  is  only  one  acid  which  can 
strictly  be  called  peculiar  to  animals,  namely, 
the  uric  acid.  The  oxalic,  benzoic,  and  acetic 
acids  are  common  to  animals  and  vegeta- 
bles. 

The  other  animal  acids  are  not  found  ready 
formed,  but  are  artificially  produced  by  various 
chemical  processes  in  which  animal  matters  are 
concerned.  Such  are  the  various  acids  from 
fat  and  oil,  the  animal  pyroacids,  the  purpuric 
acid,*  and  a  few  others.  There  are  also  cer- 
tain acids  almost  peculiar  to  individual  animals, 
such  as  the  formic,f  the  allantoic  or  amniotic,J 
the  bombic,  &c.,§  and  one  or  two  which  are  the 
products  of  disease. 

Under  the  articles  FAT,  URINE,  MILK,  and 
BONE,  will  be  found  the  details  respecting  the 
principal  animal  acids. 

(  W.  T.  Branch.) 

AC  RITA  (a,  priv.  x£tva>,  discerno,)  a  pri- 
mary division  of  the  animal  kingdom  founded  by 
Virey,  and  so  called  by  Macleay,||  composed  of 
the  lowest  classes  of  the  radiate  animals  of 
Cuvier,  and  characterised  by  an  indistinct,  dif- 
fused, or  molecular  condition  of  the  nervous 
system. 

The  necessity  for  a  dismemberment  of  the 
Radiata  of  Cuvier,  which  RudolphiH  justly  calls 
a  chaotic  group,  has  been  felt,  and  directly  or 
indirectly  expressed,  by  most  naturalists  and 
comparative  anatomists.**  It  is  impossible,  in- 
deed, to  predicate  a  community  of  structure 
in  either  the  locomotive,  excretive,  digestive, 
sensitive,  or  generative  systems,  with  respect  to 
this  division,  as  it  now  stands  in  the  "  Regne 
Animal." 

As  in  the  animal  organization  the  nervous 

*  First  obtained  by  Dr.  Prout  from  the  pure 
lithic  acid,  of  which  the  excrements  of  the  boa 
constrictor  consist. 

t  Procured  from  the  expressed  liquor  of  ants. 

t  Supposed  by  Vauquelin  to  exist  in  the  liquor 
amnii  of  tbe  cow. 

§  Extracted  by  Chaussier  from  the  silk-worm, 
but  its  existence  is  very  problematical. 

||  Horae  Entomologicae,  vol.  i.  pt.  ii.  p.  202. 

f   Synopsis  Entoxoorum,  p.  572. 

*  Lamarck  observes,  "  Les  animaux  apathlque* 
(as  he  terms  the  Acrita)  furent  tres-improprement 
appeles  zoophytes:  ils  ne  tiennent  rien  de  la  nature 
vegctale,  et  tous  generalemeut  sont  completement 
des  animaux.  La  denomination  d'animaux  ra- 
yonnes  ne  leur  convient  pas  plus  que  la  prece- 
dente  ;  car  elle  ne  'peut  s'appliquer  •,  qu'a  une  partie 
d'entr'eux  •,  et  il  s'en  trouve  beaucoup  parmi  eux 
qui  n'ont  absolunnnt  rien  de  la  forme  rayonnante." 
Anim.  sans  Vertebres  i.  p.  390. 


system  is  that  which  is  subject  to  the  fewest 
varieties,  and  as  its  relative  perfection  is  the 
surest  indication  of  the  relative  perfection  of 
the  entire  animal,  the  modifications  of  this 
system  necessarily  indicate  the  highest  or  pri- 
mary divisions  of  the  animal  kingdom,  and 
form  their  distinguishing  characters. 

Taking,  then,  the  nervous  system  as  a  guide, 
the  radiata  of  Cuvier  will  be  found  to  re- 
solve themselves  into  two  natural  groups,  of 
which  the  first,  composed  of  the  Polyastric  In- 
J'usoria  of  Ehrenberg,  the  Polypi  of  Cuvier, 
the  Entozoa  parenchyniatosa,  Cuv.  or  Sterel- 
mintlia,  and  the  Acalepha?,  differs  in  the  absence 
or  obscure  traces  of  nervous  filaments  from 
the  second  division,  including  the  Echinoderma, 
the  Entozoa  cavitaria  or  Cceldm'mtha,  the  epi- 
zoa,  and  the  Roti/'era,  Ehr.,  in  which  nervous 
filaments  are  always  distinctly  traceable,  either 
radiating  from  an  oral  ring,  or  distributed,  in  a 
parallel  longitudinal  direction,  according  to  the 
form  of  the  body. 

These  different  conditions  of  the  nervous 
system  are  accompanied  with  corresponding 
modifications  of  the  muscular,  digestive,  and 
vascular  systems,  and  a  negative  character,  ap- 
plicable to  the  higher  division  of  Cuvier's 
Radiata,  may  be  derived  from  the  generative 
system. 

With  respect  to  the  muscular  system,  we  find 
that  although  all  the  Acrita  possess  the  loco- 
motive faculty  at  some  period  of  their  exist- 
ence, and  many  never  become  fixed,  yet  that 
distinct  muscular  fasciculi  are  not  necessarily 
developed.  In  the  fresh-water  polype,  for  ex- 
ample, the  whole  of  the  homogeneous  paren- 
chyma of  which  it  consists  is  equally  con- 
tractile ;  and  even  in  the  medusa,  which  ranks 
among  the  highest  of  the  Acrita,  no  distinct 
muscular  organs  for  effecting  the  contractions 
of  the  gelatinous  disc  have  yet  been  detected. 
In  the  higher  division  of  radiata,  on  the  other 
hand,  which  from  the  filamentous  condition  of 
the  nervous  system  may  be  termed  Nemato- 
neura,  the  muscular  system  is  always  distinctly 
eliminated. 

The  difference  in  the  condition  of  the  diges- 
tive system  between  the  Acrite  and  Nemato- 
neurous  classes  is  still  more  striking:  in  the 
former  the  alimentary  canal  is  excavated  in  the 
parenchyma  of  the  body,  and  is  devoid  of  dis- 
tinct parietes :  in  the  Nematoneura  it  is  pro- 
vided with  a  proper  muscular  tunic,  and  floats 
in  an  abdominal  cavity. 

A  corresponding  difference  is  presented  by 
these  two  divisions  of  the  invertebrate  animals, 
in  the  condition  of  the  vascular  system.  Where 
traces  of  sanguiferous  organs  are  met  with  in 
the  Acrita,  they  are  equally  with  the  digestive 
organ  devoid  of  proper  parietes,  but  consist 
of  reticulate  canals  in  the  substance  of  the 
body,  generally  situated  near  the  surface,  and 
in  which  a  cyclosis  of  the  nutrient  fluids  is 
observed  analogous  to  that  of  plants,  but  not 
a  true  circulation.  This  structure  obtains  in 
the  Acrita  as  low  down  in  the  scale  as  the  poly- 
gastrica,  in  which  class  Ehrenberg  has  deter- 
mined the  existence  of  a  superficial  network 
of  vessels  containing  an  opaline  fluid.  In  those 


48 


ACRITA. 


genera  of  sterelraintha  or  parenchymatous  in- 
testinal worms  which  manifest  traces  of  the 
circulating  system,  the  fluids  undulate  in 
canals  of  a  similar  structure,  as  is  displayed  in 
the  planariae,  and  parasitic  trematoda,  and  also 
in  the  echinorhynchi,  in  some  species  of  which 
genus  the  cutaneous  canals  form  a  rich  net- 
work.* In  the  acalephae  the  condition  of  the 
vascular  system  is  equally  simple  with  that  of 
the  lowest  Acrita,  as  is  exemplified  in  the  mar- 
ginal reticulate  canals  in  the  disk  of  the  rhizos- 
toma.  In  the  Nematoneura,  on  the  contrary, 
those  classes  which  manifest  a  circulating  sys- 
tem distinct  from  the  digestive  tube,  as  the 
echinoderma  and  rotifera,  possess  vessels  with 
proper  parietes,  distinguishable  into  arteries 
and  veins. 

No  Nematoneurous  class  presents  an  example 
of  generation  by  spontaneous  fision  or  gem- 
mation, but  these  modes  of  reproduction  are 
common  in  the  Acrite  division. 

The  planariae  among  the  sterelmintha  are 
capable  of  indefinite  multiplication  by  simple 
division;  and  the  medusae  are  stated  to  pro- 
duce, not  ova,  but  ciliated  locomotive  gem- 
mules  or  internal  buds.  The  various  examples 
of  these  plant-like  modes  of  generation  which 
the  polypi  and  polygastrica  present  are  fa- 
miliar to  most  persons,  and  will  be  especially 
treated  of  under  their  respective  articles. 

The  fissiparous  and  gemmiparous  modes  of 
reproduction  are  not,  however,  the  exclusive 
modes  by  which  the  Acrite  classes  are  perpetu- 
ated. Most  of  the  sterelmintha  are  propagated 
by  means  of  ova :  in  the  cystica  and  cestoi- 
dea,  the  generative  organs  consist  of  ovaries 
alone,  or  are  cryptandrous ;  in  the  tremato 
da,  a  fecundating  gland  is  superadded  to  the 
ovary;  while  in  the  acanthocephala  the  sexes 
are  separate,  so  that  thus  early  in  the  animal 
kingdom,  we  find  typified  all  the  different 
modes  of  generation  by  which  the  race  is  con- 
tinued in  the  higher  classes  of  animals. 

The  different  conditions  of  the  important 
organic  systems  which  are  thus  seen  to  obtain 
in  the  great  group  of  animals  called  Radiata 
and  Zoophyta  fully  justify  a  partition  of 
the  group  corresponding  with  those  differ- 
ences. For  the  lower  organized  division  we 
retain  the  name  proposed  by  Macleay,  but  ex- 
tend its  application  to  the  acalephae  ;  and  thus 
constituted  it  may  be  characterized  as  follows. 

Sub-kingdom  ACRITA. — Gelatinous  polymor- 
phous animals,  without  distinct  nervous  fibre, 
or  visceral  cavities. 

Alimentary  canal  excavated  in  the  parenchyma 
of  the  body,  generally  without  an  anus. 

SanguiJ'erous  system  composed  of  reticulate 
canals  without  proper  tunics. 

Generation  in  most  fissiparous  or  gemmi- 
parous ;  in  some  oviparous.-^ 

The  Acrita  have  been  termed  Protozoa,  as 


*  Rudolph!  terms  one  species  echinorhynchus 
vasculosus,  from  this  circumstance. — Synopsis  Ento- 
zoonun,  p. 581. 

t  The  definition  of  the  Acrita  given  by  Macleay 
is  confessedly  a  negative  one  as  referred  to  animals  j 
it  is  as  follows  : 


being  on  the  first  step  of  animal  organization. 
They  are  analogous  to  the  ova  or  germs  of  the 
higher  classes,  and  have,  therefore,  been  termed 
by  Carus  Oozoa ;  and  as  the  changes  of  the 
embryo  succeed  each  other  with  a  rapidity 
proportionate  to  the  proximity  of  the  ovum  to 
the  commencement  of  its  development,  so  also 
we  find  that  in  each  class  of  Acrita  there  are 
genera  which  advance  into  close  approximation 
with  some  one  or  other  of  the  classes  belong- 
ing to  the  higher  divisions  of  the  animal  king- 
dom. It  results,  therefore,  from  this  tendency 
to  ascend  in  the  scale  of  organization  that  there 
is  greater  difficulty  in  assigning  constant  or  gene- 
ral organic  characters  to  the  Acrita  than  to  any 
of  the  higher  divisions  of  animals.  Even  in 
the  nervous  system,  we  find  as  we  are  led  step 
by  step  from  the  hydra  to  the  actinia  in 
the  class  Polypi,  that  the  nervous  globules 
begin  to  manifest  the  filamentary  arrangement 
about  the  oral  orifice  in  the  last  named  genus. 
That,  again,  in  tracing  the  successive  complica- 
tion of  the  sterelmintha  from  the  hydatid  to  the 
echinorhynchus  we  also  come  to  perceive  traces 
of  longitudinal  nervous  filaments  in  the  latter 
highly  organized  genus  of  parenchymatous 
worms.  In  the  acalephae  the  examples  of  the  ag- 
gregate form  of  the  nervous  system  would  seem 
to  be  more  numerous  and  distinct.  Ehrenberg 
has  detected  what  he  considers  as  a  nervous  sys- 
tem in  a  gelatinous  medusa;  and  Dr.  Grant 
has  recently  described  a  nervous  collar  giving 
off  simple  filaments  in  the  more  highly  or- 
ganized beroe,  which,  in  its  distinct  intestine 
and  anal  outlet,  recedes  too  far  from  the  medu- 
sidae  to  be  placed  in  a  natural  arrangement  in 
the  same  class.  Many  of  the  polygastrica  are 
endowed  with  simple  visual  organs  or  ocelli, 
in  the  form  of  red  or  yellow  spots;  similar 
organs  of  a  dark  colour  are  exhibited  by  the 
planariae,  and  Nordmann  also  describes  them 
in  some  internal  parasitic  trematoda.  Ehren- 
berg has  recently  discovered  coloured  ocelli 
in  a  medusa,  and  he  ascribes  a  sense  of 
taste  to  the  polygastrica. 

The  indications,  however,  of  the  special  senses 
in  the  Acrita  are  feeble  and  obscure,  and  in  the 
least  doubtful  instances  the  organs  are  evidently 
of  the  simplest  and  most  elementary  nature. 

For  the  most  part  all  the  different  systems 
seem  blended  together,  and  the  homogeneous 
granular  parenchyma  possesses  many  functions 
in  common. 

Where  a  distinct  organ  is  eliminated  it  is  often 
repeated  indefinitely  in  the  same  individual. 
Thus  in  the  polypi  the  nutritious  tubes  of  one 
individual  are  generally  supplied  by  numerous 
mouths,  and  it  has,  consequently,  the  semblance 


tf  Animalia  gelatinosa  polymorpha,  interaneis 
nullis  medullaque  indistincta. 

"  Os  interdum  indistinctum,  sed  nutritio  absorp- 
tioue  externa  vel  interna  semper  sistit.  Anus 
nullus. 

"  Reproductio  fissipara  vel  gemmipara,  gemmis 
modo  exteris,  modo  internis,  interdum  acervatis. 

"  Pleraque  ex  individuis  pluribus  semper  cohae- 
rentibus  animalia  composita  sistunt." — Horae  Ento- 
mologicae,  ii.  p.  224.  See  also  Lamarck,  Anim. 
saas  Vertebres,  ii.  p.  2. 


ADHESION. 


of  a  composite  animal ;  the  polygastrica  derive 
their  name  from  an  analogous  multiplication  of 
the  digestive  organ  itself.  Among  the  sterel- 
niintha  vve  find  instances  where  the  generative 
system  is  the  subject  of  a  similar  repetition, 
each  joint  of  the  lamia1  being  the  seat  of  aseparate 
ovary,  though  all  are  nourished  by  continua- 
tions of  one  simple  system  of  nutritious  tubes. 
The  calcareous  and  siliceous  sponges,  again, 
which,  in  eliminating  the  first  sketch  of  an  in- 
ternal earthy  skeleton,  seem  to  lose  the  few 
characteristics  of  animal  life  which  they  before 
possessed,  are  limited  to  the  repetition  of  a 
simple  spiculum. 

The  formative  energies  of  the  Acrita  being 
thus  expended  on  a  few  simple  operations,  and 
not  concentrated  on  the  perfect  development  of 
any  single  organ,  it  is  not  surprising  that  the 
different  classes  should  exhibit  the  greatest 
diversity  of  external  figure.*  But  it  has  been 
well  observed  that  Nature,  so  far  from  forgetting 
order,  has,  at  the  commencement  of  her  work, 
in  these  imperfect  animals  given  us  a  sketch  of 
the  different  forms  which  she  intended  after- 
wards to  adopt  for  the  whole  animal  kingdom. 
Thus  in  the  soft,  sluggish  sterelmintha  we  have 
the  outline  of  the  mollusca ;  in  the  fleshy  living 
mass  which  sui  rounds  the  earthy  hollow  axis  of 
the  polypi  natantes,  she  has  sketched  a  verte- 
brated  animal ;  and  in  the  crustaceous  covering 
of  the  living  mass,  and  the  structure  more 
or  less  articulated  of  the  polypi  vaginati  we 
trace  the  form  of  the  annulose  or  articulate 
classes. 

(Richard  Owen.) 

ADHESION,  ('from  ad-hoerere,  Lat.  adhesio, 
Fr.  adherence,  Germ,  wiederanheilung,  Ital.  ade- 
sione, )  that  process,  by  the  occurrence  of  which, 
when  two  living  surfaces,  naturally  or  artifi- 
cially separated  the  one  from  the  other,  are 
brought  into  mediate  or  immediate  contact, 
and  inflammation  is  developed,  those  surfaces 
may  become  adherent  the  one  to  the  other. 

This  adhesion  may  be  effected  either  by  the 
intervention  of  a  stratum  of  exhaled  fibrino- 
albuminous  matter,  inorganic  in  the  first  in- 
stance, but  at  a  subsequent  period  acquiring 
organization,  and  becoming  a  perfect  and  per- 
manent cellular  bond  of  union  ;  or  it  may  not 
occur  until  after  suppuration  has  been  estab- 
lished and  granulating  surfaces  are  presented ; 
these  surfaces  enter  into  adhesion,  and  in  this 
case  the  bond  of  union  is  not  so  decidedly 
cellular  in  character  as  in  the  former;  it  is  more 
or  less  dense  and  fibro-cellular. 

In  either  case,  the  medium  of  union  pre- 
sents peculiar  modifications  dependent  upon 
the  tissue  on  which  it  is  developed.  This  circum- 
stance, and  especially  the  deposition  of  osseous 
matter,  where  bony  union  is  required,  was  one 
of  the  strongest  arguments  used  for  the  purpose 
of  establishing  the  existence  of  the  presiding 
intelligent  principle  of  Stahl. 

If  the  first  process,  that  in  which  the  fibrino- 
albuminous  exhalation  obtains,  be  interfered 
with,  that  is,  if  a  more  intense  degree  of  in- 

"   Macleay,  ibid,  p.  123. 


flammation  be  developed,  such  exhalation  can 
no  longer  occur,  but  the  second  state,  that  in 
which  a  purulent  exhalation  shall  be  the  pro- 
duct, may  be  induced. 

It  is  upon  tli is  principle,  viz.  that  a  certain 
quantity  of  inflammation  shall  predispose  to 
the  first  species  of  union,  which  is  termed 
union  by  the  first  intention  ;  and  that  a  greater 
quantity  may  produce  a  purulent  exhalation, 
and  therefore  be  opposed  to  such  union,  that  is 
founded  the  following  precept.  "  When  it  is 
deemed  prudent  to  prevent  union  by  the  first 
intention,  we  have  merely  to  introduce  between 
the  surfaces,  and  retain  there  from  eighteen  to 
twenty-four  hours  a  piece  of  lint,  by  which  a 
sufficient  degree  of  inflammation  will,  usually, 
be  excited  to  ensure  a  suppurating  surface." 

From  the  time  when  the  phenomena  of  in- 
flammation were  first  carefully  studied,  until 
very  recently,  it  has  been  commonly,  if  not  uni- 
versally maintained,  that  adhesion  could  never 
be  accomplished  in  the  absence  of  inflamma- 
tion. 

In  the  present  day,  Breschet*  and  some  others 
have  endeavoured  to  establish  that  adhesion 
does  not,  necessarily,  imply  the  pre-existence  or 
co-existence  of  inflammation  ;  and  as  it  appears 
to  me  upon  very  insufficient  evidence.  They 
say  that  adhesion  may  result  from  a  "  primitive 
disposition  of  the  organization"  and  as  evi- 
dence of  the  existence  of  this  disposition,  they 
refer  to  certain  congenital  affections,  occlusion 
of  the  eyelids,  and  of  the  lachrymal  canal, 
irnperforations  of  the  mouth,  the  anus,  and  so 
on.  Why  they  should  assume  that  phenomena, 
the  mechanism  of  which  appears  identical, 
should  be  effected  by  a  totally  different  agency 
in  intra  and  in  extra-uterine  life,  it  is  not  easy 
to  understand,  and  I  believe  such  is  not  the  fact. 

We  may  have  certain  of  these  occlusions, 
accomplished  in  extra-uterine  life,  but  never 
without  the  intervention  of  inflammation  ;  and 
what  possible  reason  have  we  for  supposing 
that  if  these  occlusions  do  commonly,  nay 
always,  occur  in  consequence  of  the  develop- 
ment of  inflammatory  action,  that  this  agency 
shall  be  wanting  during  uterine  life  ?  None,  I 
apprehend,  beyond  simple  assumption. 

Imperforation  of  the  eyelids  and  occlusion 
of  the  lachrymal  canal  differ  from  imperfora- 
tion  of  the  mouth  and  of  the  anus,  in  that  the 
former  result,  not  from  the  presence  of  an 
anomalous  membrane,  but  only  from  the  union 
of  existing  membranes,  which  are  normally 
separated  the  one  from  the  other.  In  the  greater 
number  of  cases  the  eyelids  are  simply  adherent, 
either  at  one  or  many  points,  or  along  the  whole 
length  of  their  border,  and  I  would  say  are 
always  so  in  consequence  of  inflammation. 

The  other  imperforations  to  which  allusion 
has  been  made,  are  dissimilar  to  those  of  the 
eyelids.  Imperforation  of  canals  opening  upon 
the  surface  of  the  body  is  a  case  in  which,  al- 
most always,  there  has  been  an  arrest  of  de- 
velopment ;  all  the  canals  which  in  the  adult 
are  lined  by  a  mucous  membrane,  continuous 
with  the  skin  at  their  orifice,  are  naturally,  at 

*  Diet,  de  Med.  art.  Adherence. 


50 


ADHESION. 


a  certain  epoch  of  embryo  life,  imperforate. 
These  organic  states,  which  nosologists  have  so 
often  considered  as  diseases,  are,  therefore, 
simply  primitive  conditions  preserved  by  ano- 
maly, and  become  permanent  instead  of  tran- 
sient.* It  may,  therefore,  be  inferred  that  the 
greater  number  of  cases  adduced  as  evidence 
of  adhesion  in  intra-uterine  life  are  not  in 
point,  and  if  they  were  it  may  still  be  asserted, 
and  the  assertion  be  borne  out  by  analogy, 
that  they  had  not  occurred  in  the  absence  of 
inflammation. 

John  Hunter  seems  to  have  had  the  idea  that 
adhesion  may  occur  in  the  absence  of  inflam- 
mation in  certain  cases,  namely,  in  those  where 
blood  has  been  effused,  that  this  blood  may 
become  organized  and  form  a  bond  of  union. 
He  says,  "  It  does  not  seem  necessary  that 
both  surfaces,  which  are  to  be  united,  should 
be  in  a  state  of  inflammation  for  the  purpose 
of  effecting  an  union  ;  it  appears  only  necessary 
that  one  should  be  in  such  a  state,  which  is  to 
furnish  the  materials,  viz.  to  throw  out  the 
coagulating  lymph,  and  the  opposite  unin- 
flamed  surface  accepts  simply  of  the  union  ; 
nor  is  it  even  necessary  that  either  surface 
should  be  in  a  state  of  inflammation  to  admit 
of  union :  we  often  find  adhesions  of  parts 
which  can  hardly  be  called  inflamed ."f 

I  believe  that  no  solution  of  continuity  can 
be  obliterated  in  the  absence  of  inflammation, 
the  injury  which  has  occasioned  the  solution 
of  continuity,  and  the  effusion  of  blood,  being 
sufficient  to  excite  inflammation.  The  only 
circumstance  under  which  it  seems  to  me  to 
be  possible  that  union  could  be  produced  in  the 
absence  of  inflammation,  is  one  which  can  only 
rarely  occur;  and  even  then,  although  the 
possibility  of  the  occurrence  can  hardly  be 
denied,  its  reality  may  be  reasonably  ques- 
tioned. If  a  portion  of  blood,  for  instance,  be 
effused  into  a  serous  cavity,  its  colouring 
matter  is,  after  a  time,  removed,  and  a  fibrino- 
albuminous  coagulum  remains.  This  coagulum 
coming  in  contact  with  a  previously  uninflamed 
serous  membrane,  may  become  united  to  this 
membrane  :  and  it  is  believed  by  some  pa- 
thologists  that  this  union  occurs  without  the 
supervention  of  inflammation.  Another  si- 
tuation where  it  is  believed  by  certain  patho- 
logists  that  union  is  produced  by  similar 
means,  is  in  a  portion  of  artery  included  be- 
tween two  ligatures,  the  blood  which  has  been 
included  between  the  two  points  undergoing  a 
similar  change  to  that  which  I  have  already 
described,  and  adhesion  of  the  clot  to  the  in- 
ternal tunic  of  the  artery  being  effected  in  the 
absence  of  inflammation. 

Such  cases  may  carry  conviction  to  the  mind 
of  a  superficial  observer,  but  a  more  careful  in- 
vestigation will  lead  to  an  opposite  conclusion. 
My  own  observations  induce  me  to  think,  that 
of  all  the  causes  by  which  adhesive  inflam- 
mation of  serous  membranes  maybe  produced, 
the  most  remarkable  perhaps  is  an  extravasation 


*  Isid.  Geoff.  St.  Hilaire,  Hist,  des  Anomalies  de 
1'Oreanization,  t.  i.  p.  532. 

t  On  the  Blood  and  Inflam.  Ed.  1828,  p.  319. 


of  blood  into  their  cavities,  which  appears  to 
excite  just  the  precise  quantity  of  inflammation 
necessary  for  the  production  of  adhesion.  If 
we  examine  the  point  at  which  such  coagula 
are  maintained  in  contact  with  serous  mem- 
branes, before  perfect  union  is  established,  we 
shall  find  between  the  coagulum  and  the  mem- 
branes a  stratum  of  exhaled  matter,  the  exist- 
ence of  which  would  lead  to  the  conclusion 
that  the  clot  has  excited  in  the  membrane  as 
much  inflammation  as  is  necessary  for  the  pro- 
duction of  such  exhalation. 

In  solutions  of  continuity  where  blood  has 
been  effused  between  the  edges,  it  was  main- 
tained by  John  Hunter*  that  this  blood  was 
the  provisional  bond  of  union  ;  this,  I  appre- 
hend, is  not  the  case.  Whether  protected  from 
the  atmospheric  air,  which  appears  to  exercise  a 
very  decided  influence  in  decomposing  it,  as  in 
some  fractures,  or  directly  exposed  to  it,  as  in 
ordinary  solutions  of  continuity,  this  coagu- 
lum never,  during  the  early  periods,  adheres 
with  sufficient  firmness  to  attach  to  each  other 
the  borders  of  a  wound  If,  however,  any  por- 
tion of  the  coagulum  remain  after  a  fibrino- 
albuminous  exhalation  has  been  formed  upon 
the  divided  surfaces,  it  may  become  in  this  way 
organised,  and  permanently  adherent. 

After  the  preceding  remarks,  it  will  therefore 
be  held  in  this  article  that  whenever  an  adhe- 
sion has  been  effected  between  two  surfaces, 
naturally  or  artificially  separated,  that  that 
adhesion  must  have  taken  place  through  the  in- 
tervention of  inflammation  ;  that  inflammation 
arrived  at  a  certain  height  will  be  accompanied 
by  afibrino-albuminous  exhalation; — that  if  the 
inflammation  be  carried  beyond  that  point,  a 
purulent  secretion  may  be  established,  and 
when  this  is  developed,  union,  by  what  is 
termed  the  first  intention,  cannot  occur  ;  granu- 
lations are  then  developed,  and  union  by  what 
is  termed  the  second  intention,  may  follow. 
The  process  by  which  each  kind  of  union  is 
effected  I  shall  now  proceed  to  describe  in  de- 
tail. 

In  all  cases,  whether  two  naturally  separate 
tissues  are  to  be  united,  or  whether  a  solution 
of  continuity  is  to  be  repaired,  there  appears  to 
be  a  certain  uniformity  in  the  means  by  which 
the  union  is  accomplished.  Inflammation  is 
developed,  and  a  material  susceptible  of  or- 
ganization is  exhaled,  which  becomes  the  con- 
necting medium.  This  matter  in  its  greatest 
state  of  simplicity  is  exuded  under  the  form 
of  lymph,  upon  the  surface  of  the  parts  to  be 
united  ;  it  is  coagulated,  and  transformed  into 
a  soft  pulp  ;  it  gradually  increases  in  density, 
acquires  a  reticular  or  porous  aspect,  a  first 
rudiment  of  organization,  and  as  a  second  de- 
gree exhibits  in  its  substance  red  spots,  then 
striae,  which  have  the  appearance  of  vascular 
ramifications,  and  at  last  bloodvessels. 

It  is  hardly  possible  to  collect  this  lymph  in 
a  state  of  purity  except  in  the  canal  of  an  artery 
where  it  has  been  exhaled  between  two  ligatures. 
It  is  then  presented  under  the  form  of  a  whitish 
matter,  of  a  soft  and  fibrinous  consistence,  which 

*  Loc.  cit.  p.  253. 


ADHESION. 


is  rendered  particularly  evident  when  the 
lymph  is  submitted  to  the  action  of  boiling 
water ;  it  dissolves  almost  completely  in  a  warm 
solution  of  caustic  potash,  though  less  promptly 
than  thickened  albumen,  but  more  rapidly 
than  fibrine. 

This  matter,  which  is  probably  the  same  with 
that  by  which  all  parts  of  the  body  are  nourished 
and  preserved,  but  in  the  case  before  us  secreted 
in  increased  quantity  and  preserving  a  strong 
tendency  to  coagulate,  has  nothing  in  it  which 
is  necessarily  opposed  to  the  healthy  action  of 
the  animal  economy.  In  fact  we  may  consider 
exudation  as  a  nutrition,  much  exalted  by  in- 
flammatory action,  which  is  itself  only  an 
exaltation  of  the  vital  properties. 

We  may  admit  four  periods  or  states  of 
change  to  which  this  material  which  consti- 
tutes the  medium  of  adhesion  is  subject — 
a  first,  the  period  of  development;  a  second, 
a  period  of  increase ;  a  third,  that  of  organi- 
zation; and  a  fourth,  that  of  mutation;  in 
which  it  is  changed  into  a  cellular  tissue. 

In  the  first  period,  we  find  that  in  twenty- 
four,  and  sometimes  even  in  nineteen  hours 
after  we  have  irritated  a  serous  membrane,  the 
pleura  of  a  dog,  or  of  a  rabbit  for  instance,  that 
this  membrane  is  much  injected,  and  that  there 
has  been  formed  upon  its  surface  an  extremely 
thin,  pulpy  stratum,  which  may  very  easily  be 
removed  :  the  second  period  commences  when 
this  exudation  has  assumed  a  membraniform 
appearance,  and  is  characterized  by  an  aug- 
mentation of  thickness  and  of  density  :  the  third 
period  is  characterised  by  still  greater  density 
and  the  presence  of  vessels.  Stoll  believed  that 
these  membranes  might  become  organised  in 
twelve,  nine,  or  even  eight  days  after  the  inva- 
sion of  the  disease.  Home  believed  that 
vessels  might  appear  in  twenty-four  hours. 

In  the  fourth  period,  the  membrane  loses 
some  of  its  thickness,  and  every  day  assumes 
more  and  more  of  the  appearance  of  cellular 
tissue ;  and  when  perfected,  there  is  not  only 
identity  of  appearance  between  cellular  tissue 
and  these  membranes,  but  also,  according  to 
Laennec,*  identity  of  use,  and  even  of  disease, 
except  that  this  tissue  very  rarely  contains  adi- 
pose matter,  f 

Nothing  in  our  subject  is  more  curious  or 
more  important  than  the  organisation  of  these 
membranes ;  their  vessels  are  thin,  delicate, 
and  similar  to  those  of  the  pia  mater ;  their 
form  and  their  direction  are  extremely  simple ; 
they  are  not  tortuous,  and  they  proceed,  usually, 
in  fasciculi,  almost  like  the  lymphatics  of  the 
extremities.  We  may  easily  convince  ourselves 
that  their  formation  is  sometimes  very  prompt, 
by  the  perusal  of  the  following  case.  A  por- 
tion of  strangulated  intestine,  which,  after  the 
incision  of  the  herniary  sac,  did  not  present 
many  bloodvessels,  was  examined  after  the 
death  of  the  individual,  which  occurred  in 
twenty-nine  hours  after  the  operation,  by  Sir 
Everard  Home  :  he  found  the  portion  of  in- 

*  De  1'Auscultation  Mediate,  torn.  ii.  p.  293. 
t  Laennec  states  that  he  has  "  quelquefois  "  seen 
fat  developed  in  these  cellular  laminae.  Loc.  cit. — ED. 


testine  which  had  been  strangulated  profoundly 
inflamed,  and  covered  in  many  points  by  a 
"  layer  of  coagulable  lymph :"  this  intestine  was 
injected  with  very  fine  size,  and  two  small 
bloodvessels  were  found  passing  along  through 
the  new  membrane  into  which  the  injection 
had  penetrated. 

According  to  Laennec*  we  may  observe  the 
following  phases  in  the  organisation  of  these 
membranes. 

The  rudiments  of  bloodvessels  are  at  first 
presented  under  the  form  of  striae  of  blood, 
which  are  more  voluminous  than  the  vessels  by 
which  they  are  to  be  succeeded.  The  blood 
appears  to  have  penetrated  into  the  tissue  of  the 
membrane,  as  if  pushed  by  a  strong  injection ; 
yet  in  examining  the  points  of  the  membrane,on 
which  the  layer  of"  coagulable  lymph  "  is  depo- 
sited, we  find  no  destruction,  nor  any  orifice  of 
a  vessel,  but  only  spots  of  blood.  Soon,  ac- 
cording to  Laennec,  "  these  lines  of  blood  take 
a  cylindrical  form,  and  ramify  in  the  manner  of 
bloodvessels,  still  preserving  a  considerable 
diameter.  If,  at  this  epoch,  we  carefully  ex- 
amine them,  we  find  that  these  vessels  have  an 
external  coat  which  is  soft,  and  formed  of  blood 
scarcely  concrete,  to  which  they  owe  their 
colour.  After  having  incised  this  coat,  we 
withdraw  a  sort  of  mould,  or  rounded  fasci- 
cular  body,  whitish  and  fibrous,  evidently 
formed  of  concrete  fibrine,  and  of  which  the 
centre  appears  perforated  and  permeable  to  the 
blood.  Uowever  small  be  the  canal,  it  is  these 
fibrous  fasciculi  which  should,  by  thinning,  form 
the  tunics  of  the  bloodvessels." 

These  delicate  observations  have  not,  so  far 
as  I  know,  been  confirmed  by  other  observers  : 
those  authors  who  have  spoken  of  newly  deve- 
loped vessels,  among  whom  we  may  name 
Hunter,  Monro,  Soemmering,  do  not  speak  of 
this  mode  of  development.  Hunter  and  Home 
explain  it  differently;  they  say  there  is  at  first 
a  formation  of  small  ampullae,  containing  only 
a  colourless  fluid :  second,  a  union  of  these 
ampullae,  and  production  of  a  vascular  net- 
work, not  yet  supplied  with  blood :  third,  an 
inosculation  between  the  newly  developed 
vessels,  and  those  of  the  inflamed  membrane, 
and  next  the  ingress  of  blood.  Beclard  was  of 
the  same  opinion.f  Gendrin  thinks  that  the 
new  vessels  are  developed  by  the  action  of  the 
primitive  vessels  ;  he  says,  "  that  the  blood  is 
excreted  by  the  adjoining  capillaries,  opening 
into  the  soft  and  fibrinous  tissue  deposited  in 
the  inflamed  part;  this  blood  becomes  concrete, 
and  the  vascular  impulsion,  a  tergo,  being  con- 
tinued, new  blood  is  pushed  into  it  and  hollows 
it.  Thus  the  little  vascular  rudiment  is  pro- 
longed into  an  irregular,  flexuous,  and  unequal 
stria,  which  meets  another  and  unites  with  it, 
continuing  in  this  way  to  prolong  itself  into 
the  least  resistent  portion  of  the  fibrinous  de- 
position. "J 

To  some  extent  the  opinions  of  Laennec  and 


*  Loc.  cit. 

t  Anat.  Generale,  p.  195. 

t  Hist.  Anat.  des  Inflam.   torn.  ii.   $   1303.  and 
1571. 

E  2 


ADHESION. 


Gendrin  are  alike ;  they  believe  that  the  forma- 
tion of  the  new  vessel  consisted  in  this,  that  the 
little  clot  was  perforated,  and  that  it  was  pene- 
trated by  liquid  blood. 

The  experiments  of  Brande*  would,  however, 
lead  to  a  different  conclusion  ;  he  shewed  that 
the  air  contained  in  the  blood  had  much  in- 
fluence in  the  formation  of  bloodvessels.  This 
air  is  carbonic  acid  gas,  and  its  quantity  appears 
to  be  nearly  equal  in  the  two  kinds  of  blood  ; 
being  estimated  at  a  cubic  inch  for  every  ounce 
of  blood.  This  gas  maybe  separated  from  the 
blood  by  the  air-pump,  and  it  escapes  with  a 
kind  of  bubbling  or  effervescence,  causing  the 
ascent  of  the  mercury  in  a  barometer  attached 
to  the  apparatus. 

It  has  been  remarked  that  during  the  coagu- 
lation of  the  blood,  a  large  quantity  of  carbonic 
acid  gas  escapes;  this  coagulation,  observed 
under  the  microscope,  has  shewn  that  the  gas, 
by  escaping  in  all  directions,  forms  a  net-work 
of  canals,  the  branches  of  which  anastomose 
with  each  other ;  and  that  this  net-work  pre- 
serves its  form  after  desiccation.  It  has  also 
been  established  that  it  is  this  gas  which  forms 
those  canals  in  coagulated  blood ;  because,  if 
by  means  of  the  air-pump  we  deprive  the  blood 
of  it,  before  it  is  coagulated,  they  do  not  occur. 

Sir  E.  Home  has  even  injected  the  vessels 
which  were  developed  in  the  coagulum  soon 
after  the  blood  was  taken  from  a  vein.  If  the 
formation  of  new  vessels  occur  even  in  a  coa- 
gulum of  blood  removed  from  the  living  body, 
but  preserving  still  a  certain  quantity  of  its 
heat,  and  of  its  vitality,  with  more  reason  might 
we  expect  that  a  similar  phenomenon  should 
obtain  during  life :  and  this  fact  has  been  de- 
monstrated by  experiments  performed  on  a 
rabbit,  in  which  had  been  produced  a  hemor- 
rhage from  a  small  branch  of  the  mesenteric 
artery  :  after  twenty-four  hours,  the  coagulum 
which  was  formed  was  injected. 

The  formation  of  vessels  in  coagulated  blood, 
by  means  of  the  carbonic  acid  gas  which  tra- 
verses it  in  all  directions,  is  in  perfect  accord- 
ance with  the  observations  which  have  been  made 
by  M.  Bauer  upon  germinating  wheat,  which 
were  instituted  for  the  purpose  of  shewing  the 
influence  of  the  globule  of  air.  These  globules 
are  manifested  below  a  bud  of  mucilaginous 
substance ;  they  push  it  forward,  elongate  it, 
and  thus  form  a  filament. 

I  do  not,  however,  believe  that  either  of 
these  theories  correctly  explains  the  pheno- 
menon. 

It  was  for  a  long  time  believed  that  false 
membranes  were  never  organised  ;  that  nature 
had  given  to  the  parts  of  our  economy  an 
almost  unlimited  power  of  development,  but 
not  the  faculty  of  communicating  life  to  the 
products  of  the  circulation;  that  false  mem- 
branes appeared  to  be  organised  only  because 
they  constituted  a  kind  of  frame-work  through 
which  vessels  from  the  inflamed  tissue  might 
be  prolonged :  ulterior  observations,  however, 
have  shewn  that  these  media  are  really  or- 
ganised. We  have  no  general  rules  as  to  the 


time  when  such  organisation  shall  commence. 
It  seems  to  be  dependent  upon  inexplicable 
individual  dispositions.  It  may,  however,  be 
remarked,  that  the  greatest  analogy  exists  be- 
tween the  mode  of  development  of  vessels  in 
these  media  of  adhesion  and  their  mode  of 
production  in  the  membrane  of  the  yolk  in  the 
chick,  saving  always  this  remarkable  circum- 
stance, namely,  the  inconstancy,  the  irregu- 
larity of  the  work  of  organisation  in  the  former, 
and,  on  the  contrary,  the  constancy  and  the 
regularity  of  the  occurrence  in  the  latter 
case. 

These  media  are  in  fact  secreted  by  a  tissue, 
the  vitality  of  which  is  exalted  to  a  certain 
extent,  and  it  appears  to  impress  upon  the  pro- 
duct of  its  secretion  a  commencement  of  vitality, 
as  in  generation.  All  these  circumstances  ap- 
pear to  me  to  demonstrate  that  these  vessels  are 
the  product  of  a  spontaneous  generation — a  true 
epigenesis ;  so  indeed,  to  a  certain  extent, 
thought  Hunter.  lie  says,  "  In  a  vast  number 
of  instances  I  have  observed,  that  in  the  sub- 
stance of  the  extravasation  there  were  a  great 
number  of  spots  of  red  blood,  so  that  it  looked 
mottled.  The  same  appearance  was  very  ob- 
servable on  the  surface  of  separation  between 
the  old  substance  and  the  new,  a  good  deal 
like  petechial  spots.  Was  this  blood  extra- 
vasated  along  with  the  coagulating  lymph  ? 
In  this  case  I  should  rather  have  supposed  it 
would  have  been  more  diffused.  I  have  there- 
fore suspected  parts  have  the  power  of  making 
vessels,  and  red  blood,  independent  of  the 
circulation."* 

If  the  inflammation  be  not  strictly  confined 
to  that  state  in  which  the  albumino-fibrinous 
exhalation  is  accomplished,  but  proceeds  to  the 
next  stage,  the  exhalation  entirely  changes 
character ;  pus  is  produced,  a  granulating  sur- 
face is  developed,  and  union  is  accomplished 
by  the  intervention  of  another  tissue,  and  by  a 
slower  process  than  that  which  we  have  already 
described.  This  is  the  process  which  is  always 
observed  in  mucous  membranes,  scarcely  ever 
in  serous;  for  in  the  former,  the  albumino-fibri- 
nous matter  never  becomes  organised,  and  can 
therefore  never  be  the  medium  of  a  permanent 
union.  In  these  membranes,  if  adhesion  occur, 
the  inflammation  must  proceed  to  the  succeed- 
ing stage.  Adhesion  of  mucous  membranes, 
however,  does  not  often  occur — it  is  not  com- 
patible with  the  performance  of  their  functions. 

Soon  after  the  secretion  of  pus  is  established 
granulations  are  developed,  and  a  state  favour- 
able to  adhesion  is  produced.  The  develop- 
ment of  granulations  occurs  in  the  following 
manner : — upon  the  surface, about  to  suppurate, 
is  exuded  a  layer  of"  coagulable  lymph  ;"  this 
lymph  becomes  penetrated  by  bloodvessels, 
nerves,  and  absorbents,  which  give  birth  to 
granulations.  These  granulations  are  developed 
much  earlier  in  some  tissues  than  in  others — 
in  a  stump,  for  instance,  we  see  them  first 
upon  the  cellular  tissue,  then  upon  the  mus- 
cular, then  the  fibrous,  and  lastly  upon  the 
osseous  tissue  :  they  appear  to  form  as  much 


Phil.  Trans.  1818.  pp.  172  and  185. 


*  Loc.  cit.  pp.  388-9. 


ADHESION. 


more  readily  as  the  tissue  may  be  more  cellular 
and  vascular.  That  these  organs  are  very  va.s- 
cular  is  evident  from  the  rapidity  with  which 
they  bleed  upon  the  slightest  contact ;  that  they 
contain  nerves  is  shewn  by  the  pain  which 
is  produced  in  them  by  the  slighest  touch : 
does  not  their  prompt  destruction  by  slight 
causes  seem  to  indicate  the  existence  of  absor- 
bents / 

No  one  has  made  more  interesting  researches 
into  the  nature  of  these  bodies  than  Sir  Everard 
Uome.*  lie  carefully  observed  the  changes 
which  occurred  in  an  ulcer  of  the  leg.  By  using 
a  lens  which  enlarged  objects  eight  times,  he 
saw  that  granulations  were  formed  in  the  fol- 
lowing manner :  first,  is  seen  a  mass  of  capil- 
lary vessels  differently  arranged ;  secondly, 
small  sinuosities  containing  pus.  The  ulcer  ob- 
served during  ten  minutes,  offered,  in  the  first 
place,  an  extremely  thin  and  transparent  pel- 
licle, under  which  were  disengaged  globules  of 
gas,  then  canals  having  a  horizontal  direction, 
and  containing  blood.  The  tunics  of  these 
vessels  were  so  delicate  that  they  were  ruptured 
by  the  simple  motion  of  the  leg.  These  canals 
anastomose  with  each  other,  taking  different 
directions  ;  those  which  are  developed  the  first 
were  the  next  day  changed  into  true  vessels. 
Soon  these  new  vessels  have  enough  of  solidity 
to  admit  of  our  passing  a  needle  under  them 
and  raising  without  rupturing  them.  The  forma- 
tion of  all  these  parts  is  due,  according  to 
Home,  to  the  coagulation  of  pus,  and  the  de- 
velopment of  carbonic  acid  gas ;  "  for  if  the 
puriform  matter  be  wiped  off,  these  phenomena 
are  not  produced."  \Vhen,  on  the  contrary,  he 
employed  substances,  calculated  to  coagulate 
the  pus,  the  formation  of  those  vessels  was 
accelerated.  He  concludes  from  his  experiments 
that  bloodvessels  are  developed,  almost  as  it 
were  under  the  eye  of  the  observer ;  that  they 
are  not  a  prolongation  of  pre-existing  vessels ; 
that  they  are  formed  independently  of  the  action 
of  the  subjacent  solid  parts.  So  far,  therefore, 
although  the  processes  may  differ,  yet  the 
general  points  of  union  between  the  two  modes 
is  singularly  similar. 

While  suppuration  is  proceeding,  another 
operation  is  in  progress  under  the  layer  of  gra- 
nulations. A  stratum  of  cellular  tissue,  at  first 
simple  and  not  very  resistent,  afterwards  fibro- 
cellular,  and  lastly  fibrous,  is  organised  insensi- 
bly to  serve  as  the  base  of  the  succeeding  me- 
dium of  union. 

When  granular  surfaces  are  brought  into  con- 
tact, and  the  tendency  to  secrete  pus  has  ceased, 
they  enter  into  adhesion.  This  tendency  is 
marked  by  a  diminution  of  activity  in  the  gra- 
nulations; the  membrane  ceases  to  secrete  pus, 
and  the  granulations  become  firmer  and  con- 
tracted :  before  union  can  be  effected,  the  sup- 
purating surface  must,  therefore,  change  its 
nature — must  be  destroyed.  A  state  like  that  in 
simple  union  by  the  first  intention  is  produced  ; 
the  secretion  becomes  plastic,  and  somewhat 
analogous  to  that  which  accompanies  that  mode 
of  union. 

*   Home  on  Ulcers. 


When  these  new  tissues  or  media  of  union 
are  developed  between  surfaces  naturally  free, 
the  structure  of  the  two  portions  of  the  organ 
between  which  they  are  seated  becomes  changed. 
In  serous  or  mucous  membranes,  as  well  as  in 
those  surfaces  which  are  immediate  modifica- 
tions of  these  two  systems,  this  may  be  ob- 
served. When,  for  example,  the  pleura  costalis 
becomes  adherent  to  the  pleura  pulmonalis,  the 
point  of  union  is  no  longer  a  serous  membrane ; 
the  free  surface  having  disappeared,  an  un- 
interrupted continuity  is  established  between 
the  subserous  cellular  tissue  of  the  pleura  cos- 
talis, and  the  interlobular  cellular  tissue  of  the 
lung.  This  conversion  is  frequent  in  the  peri- 
toneum ;  in  the  tunica  vaginalis  a  similar  effect 
is  produced  by  the  common  operation  for  hy- 
drocele  ;  in  synovial  membranes  a  similar  effect 
occurs  in  what  is  termed  false  ankylosis. 

Having  described  the  general  laws  by  which 
the  phenomena  of  adhesion  are  governed,  1 
shall  now  point  out,  generally,  the  modifica- 
tions which  are  impressed  upon  it  in  different 
tissues. 

It  is  upon  serous  membranes  that  we  may 
with  most  advantage  study  the  process  of  ad- 
hesion, not  only  because  it  is  more  rapidly 
developed  there,  but  because  it  much  more 
frequently  occurs  there  than  in  other  tissues. 
If  we  examine  the  surfaces  of  two  such  mem- 
branes which  have  been  recently  united,  com- 
mencing at  a  certain  distance  from  the  point  of 
adhesion,  we  see  the  layer  of  coagulable  matter 
effused  between  the  two  surfaces  become  thinner 
as  we  approach  the  point  of  contact.  If  the 
adhesion  be  sufficiently  recent  to  admit  of  our 
separating  the  surfaces,  we  see  the  intermediate 
layer  tearing,  but  remaining  adherent  to  the 
inflamed  surfaces.  If  the  inflammation  be 
more  advanced,  and  the  pseudo-membrane  be 
more  dense  and  organised,  we  find  that  the 
very  thin  layer  of  new  deposition  by  which  the 
union  has  place  is  more  resistent  than  the 
thicker  layer  of  organisable  matter  by  which  it 
is  surrounded  ;  and  at  a  later  period  we  may 
discover  vascular  filaments  attaching  the  ad- 
herent portion  of  the  new  tissue  to  that  upon 
which  it  has  been  developed.  These  filaments 
are  as  much  more  evident  as  the  adhesion  is 
more  immediate  :  of  this  we  may  very  easily 
assure  ourselves  by  cutting  transversely  two 
portions  of  digestive  tube  which  have  become 
to  a  certain  extent  adherent  by  their  external 
tunic.  The  adhesion  may  be  already  veiy 
solid  at  the  points  where  contact  is  so  imme- 
diate that  we  can  scarcely  distinguish  the  in- 
terposed matter.  Very  delicate  red  capillaries 
creep  through  this  matter,  whilst  perhaps  at  the 
distance  of  some  lines,  and  even  at  the  centre  of 
an  already  organised  point,  the  contact  having 
been  less  immediate,  a  plastic  layer  of  one, 
two,  or  more  lines  in  thickness,  may  be  seen 
uniting  the  surfaces,  but  not  presenting  either 
the  solidity  or  the  organisation  of  the  exces- 
sively thin  layer  which  adjoins  it. 

When  these  adhesions  have  existed  for  a  cer- 
tain time,  the  serous  structure  completely  dis- 
appears. This  destruction  of  serous  membranes 
at  the  adherent  point  is  very  evident  around 


54 


ADHESION. 


herniae  which  have  been  inflamed ;  the  intestines 
engaged  in  the  tumour  are  enveloped  by  a 
more  or  less  dense  layer  of  cellular  tissue ;  and 
hence  many  herniae  thus  circumstanced  have 
been  described  as  having  no  hernial  sac.  This 
sac  has,  however,  originally  existed,  but  has 
disappeared  by  the  adhesions  which  have  been 
formed  between  it  and  the  displaced  organs, 
adhesions  by  which  the  cellular  tissue  which 
replaces  the  serous  membrane  has  been  deve- 
loped. 

If  we  consider  these  adhesions  in  relation  to 
their  frequency  in  the  serous  cavities,  we  see 
that  they  exist  most  frequently  in  the  pleura, 
existing  in  nearly  half  the  adult  bodies  ex- 
amined. After  the  pleura  comes  the  perito- 
neum, then  the  pericardium ;  those  of  the  tunica 
vaginalis  are  less  common,  but  the  arachnoid 
is,  of  all  serous  membranes,  especially  relative 
to  its  extent,  that  where  these  adhesions  are 
most  unfrequent. 

The  absence  of  mobility  appears  singularly 
to  favour  this  phenomenon :  thus  in  the  pleura 
they  most  frequently  occupy  the  superior  parts, 
and  in  the  peritoneum  most  frequently  occur 
between  the  viscera  forming  a  hernia,  and  be- 
tween the  convex  surface  of  the  liver  and  the 
diaphragm. 

The  membranes  between  which  such  adhe- 
sions occur,  must  usually,  of  course,  be  in 
intimate  relation,  the  one  with  the  other 
during  the  time  when  the  process  is  in  progress 
of  accomplishment,  though  now  and  then  the 
distance  is  considerable ;  but  they  may  after- 
wards become  separated  to  great  distances : 
those  cellular  bands  which  are  so  commonly 
seen  in  the  thorax  are  evidences  of  this  fact. 

Some  circumstances  tend  to  demonstrate 
that  these  bands  in  serous  structure  may  at  a 
certain  period  of  their  existence  be  absorbed 
and  disappear,  and  the  secreting  surface  be 
reproduced.  M.  Ribes  states  that  occasi- 
onally we  do  not  find  any  trace  of  such  bands, 
nor  any  adhesion  in  the  peritoneum  of  persons 
who  have  had  penetrating  wounds  of  the  ab- 
domen. Beclard  examined  an  insane  person 
who  had  several  times  stabbed  himself  in  the 
abdomen.  At  the  points  where  the  more 
recent  of  these  wounds  had  been  inflicted 
considerable  adhesions  were  found;  beneath  the 
older  cicatrices  no  vestige  of  adhesion  was 
found.  A  case  of  artificial  anus  occurred  in 
the  practice  of  M.  Dupuytren,  by  which  faecal 
matter  passed  during  twelve  days.  The  pa- 
tient died  at  the  end  of  seven  months.  At  the 
examination  after  death,  it  was  found  that  the 
portion  of  intestine  in  which  the  accidental 
opening  had  existed,  was  distant  from  the  ab- 
dominal cicatrix  between  four  and  five  inches. 
A  very  attenuated  cellular  band  extended  from 
the  cicatrix  to  the  portion  of  intestine.  Doubt- 
less a  short  time  would  have  sufficed  for  the 
absorption  of  this  band,  when  the  intestine 
would  have  been  set  at  liberty  and  the  serous 
surface  restored. 

In  the  course  of  lectures  which  Bichat  de- 
livered only  a  few  months  before  his  death, 
he  maintained  that  adhesion  was  never  pro- 
duced between  mucous  surfaces,  and  that  con- 


sequently the  cavities  lined  by  this  tissue  were 
never  obliterated.  Few  statements  have  given 
rise  to  more  extensive  discussion  than  this ; 
few  discussions  have  up  to  the  present  moment 
been  attended  by  less  satisfactory  results.  In 
his  first  dictum  I  believe  he  was  clearly  right, 
in  the  second  as  clearly  wrong. 

Mr.  Hunter's  opinion  was  in  accordance 
with  that  of  Bichat :  he  says,  "  that  in  all  the 
outlets  of  the  body  called  mucous  membranes, 
the  order  of  inflammation  differs  from  that 
which  occurs  in  cellular  membrane,  or  in  cir- 
cumscribed cavities.  In  these  latter  adhesive 
inflammation  is  immediately  admitted  to  ex- 
clude, if  possible,  suppuration,"  In  internal 
canals,  where  adhesions  would  in  most  cases 
prove  hurtful,  the  parts  run  immediately  into 
the  suppurative  inflammation,  the  adhesive  in- 
flammation being  in  common  excluded.* 

Mucous  membranes,  when  unchanged  by 
disease,  are  not  capable  of  becoming  adherent 
the  one  to  the  other,  and  the  reason  of  this  is 
simple.  1  have  already  stated  that  no  per- 
manent adhesion  can  occur  in  the  living  body 
without  the  intervention  of  a  new  tissue,  which 
at  a  certain  indefinite  or  undetermined  period 
of  its  existence  becomes  organized. 

A  pseudo-membrane  of  considerable  extent 
may  be  thrown  out  upon  an  inflamed  mucous 
surface;  but  this  membrane,  1  apprehend, 
never  becomes  organised,  and  union  between 
mucous  surfaces  cannot  therefore  be  permanent 
unless  some  other  agency  be  called  into  action. 
But,  as  soon  as  inflammation  has  destroyed  the 
characters  from  which  these  membranes  derive 
their  name ;  when  the  mucus,  which  like  an 
inorganic  layer  appears  to  oppose  itself  so 
successfully  against  immediate  contact,  thereby 
preventing  the  organization  of  the  effused  mat- 
ter, no  longer  exists ;  when  the  cellular  element 
which  forms  the  basis  of  this  membrane  is 
developed,  then  adhesion  by  means  of  the 
union  of  granular  surfaces  is  effected  with  the 
greatest  facility ;  of  this  we  have  evidence  in 
most  of  the  mucous  canals.  It  is  not  rare, 
for  instance,  to  meet  with  complete  obliteration 
of  the  vagina,  of  the  cystic  duct,  and  so  on. 

It  is  stated  very  generally  that  the  opinion 
of  Bichat  is  entirely  unfounded  ;  that  inflam- 
mation of  the  vagina  is  followed  by  complete 
occlusion,  without  destruction  or  transforma- 
tion of  the  mucous  membrane,  and  that  similar 
effects  may  occur  in  the  Fallopian  tubes,  the 
uterus,  and  other  mucous  canals.  That  these 
are  produced  is  perfectly  true,  but  never  until 
the  disorganization  to  which  I  have  alluded 
has  occurred. 

It  is  maintained  triumphantly  as  a  con- 
firmation of  the  opinion  that  no  transformation 
occurs,  that  when  these  adhesions  are  sepa- 
rated, we  have  the  healthy  mucous  membrane 
performing  its  functions  as  before.  This,  how- 
ever, is  not  the  case  ;  the  membrane  is  essen- 
tially different,  and  it  is  not  without  difficulty 
that  we  can  overcome  its  tendency  to  enter 
into  adhesion  again.  That  a  membrane  is  pro- 
duced, which  performs  functions  analogous  to 

*  Loc.  cit.  p.  305. 


ADIPOCERE. 


the  primitive  membrane,  is  true.  If  we  ex- 
amine a  fistulous  canal  which  has  existed  for 
a  certain  time,  we  find  it  invested  by  a  mem- 
brane similar  in  appearance,  and  performing 
an  analogous  function  to  the  primitive  mucous 
membrane, — so  rapidly  does  nature  under  cer- 
tain circumstances  adapt  an  organ  to  the  per- 
formance of  the  function  to  which  it  is  des- 
tined. 

As  it  is  therefore  upon  the  organization  of 
this  pseudo-membrane  that  the  species  of  union 
of  which  I  am  treating  is  dependent,  some  re- 
mark upon  that  subject  becomes  necessary.  It 
has  been  maintained  by  Albers,  Suemmering, 
andLarrey,  that  these  new  formations  upon  mu- 
cous membranes  may  become  organized.  The 
former  of  these  gentlemen  believes  that  the 
false  membrane  of  croup  is  commonly  organ- 
ized. Soemmering,  it  is  said,  possessed  pre- 
parations which  demonstrated  the  fact.  Cail- 
leau*  supports  this  opinion,  as  well  as  Vil- 
lermef  and  Guersent.J  I  have  never  seen 
this  membrane  present  the  slightest  vestige  of 
organization,  nor  have  I  ever  found  any  one, 
with  the  exceptions  I  have  named,  who  has, 
although,  to  my  knowledge,  they  have  been 
sought  for  during  many  years,  by  a  number 
of  the  most  competent  observers  of  the  present 
day.  And  as  I  believe  the  investigations  of 
morbid  phenomena  are  more  accurately  made 
at  present  than  at  any  former  period,  I  adhere 
to  the  opinion  that  organization  of  these  mem- 
branes upon  mucous  surfaces  never  occurs; 
and  that  union  by  "  the  first  intention "  can 
never  occur  in  those  canals  which  are  invested 
by  mucous  membrane.  But  when  the  com- 
position of  the  mucous  membrane  becomes 
destroyed  or  disorganized  by  inflammation,  and 
a  granular  surface  is  presented,  adhesion  may 
be  and  is  frequently  produced. 

The  epidermis  with  which  the  skin  is  fur- 
nished forms  an  inorganic  stratum  which  is 
opposed  to  all  adhesion;  but  remove  this 
epidermis,  render  the  surface  bleeding,  or  sup- 
purating, and  adhesion  may  be  produced  with 
the  greatest  facility.  It  is  against  this  ten- 
dency we  have  constantly  to  struggle  for  the 
purpose  of  preventing  the  adhesion  of  fingers 
to  each  other,  to  the  palm  of  the  hand,  and 
so  on, — so  common  a  consequence  of  burns. 
Adhesion  may  in  this  tissue  occur,  therefore, 
by  the  development  of  the  fibrino-albuminous 
medium,  or  by  that  of  granulations.  The 
synovial  membrane  of  joints  may  become 
adherent,  constituting  a  species  of  ankylosis, 
which  is  termed  "  false."  In  these  cases  the 
secretion  of  synovia  diminishes  and  ultimately 
ceases,  the  contiguous  surfaces  lose  their  polish, 
become  rugous,  and  contract  adhesions.  (See 
JOINTS.)  In  osseous  tissues,  adhesion  may 
be  effected  either  through  the  agency  of  the 
albumino-fibrinous  exhalation  already  de- 
scribed, or  that  of  granulations.  (See  BONE.) 
In  cartilaginous  tissues  the  mechanism  of  ad- 

*  Rapport  du  Concours  sur  le  Croup. 

t  Diet,  des  Sc.  Med.  torn,  xxxii.  p.  260. 

t  Diet,  de  Med   art.  Croup. 


hesion  is  different ;  and  in  speaking  of  the 
process  in  these  tissues,  it  is  necessary  to  di- 
vide the  tissue  into  those  which  are  invested 
by  a  more  or  less  dense  fibrous  perichondrium, 
and  those  which  are  without  it.  To  the  first 
appertain  the  cartilages  of  the  ribs,  of  the 
larynx,  and  all  those  which  Bichat  termed  fibro- 
cartilages.  The  second  class  comprehend  the 
diarthrodial.  It  is  in  fact,  I  believe,  upon  the 
presence  or  absence  of  the  perichondrium,  that 
are  dependent  the  principal  differences  which 
are  presented  in  the  pathological  condition  of 
these  organs.  The  non-diarthrodial  as  well 
as  the  fibro-cartilages,  when  they  are  ruptured 
or  divided,  are  not  united  by  a  cartilaginous 
substance. 

In  the  wounds  of  cartilages,  with  loss  of 
substance,  there  is  formed  a  kind  of  cellulous 
matter,  which  is  a  secretion  from  the  perichon- 
drium ;  in  fact  no  phenomena  of  reproduction 
are  observed  where  this  membrane  does  not 
exist ;  thus  it  is  never  observed  in  diarthrodial 
cartilages.  We  may  cut  and  mutilate  these 
latter,  and  after  many  days  we  shall  find  the 
wound  almost  as  it  was  on  the  first  day. 
When  the  cartilages  of  the  ribs  are  ruptured, 
their  union  is  often  effected  by  an  osseous  ring 
which  surrounds  the  two  fragments.  See  the 
articles  ARTERY,  ENCEPHALON,  NERVE,  FI- 
BROUS TISSUE,  MUSCLE,  VEIN,  for  the  pheno- 
mena of  adhesion  in  these  structures. 

BIBLIOGRAPHY. — Freeke,  on  the  art  of  healing, 
cicatrising,  incarning,  &c.  8vo.  Lond.  1748.  Bezoet, 
De  modo  quo  natura  solutum  redintegrat.  4to. 
Lugd.  Batav.  1763.  (Rcc.  in  Sandifort  Thes.  Diss. 
vol.  iii.  p.  147.)  Spallanzani,  Prodromo,  &c. 
sopra  la  reproduzione  animali,  4to.  Modena,  1768. 
Ejus,  Opiiscoli  de  fisica,  &c.  2  vol.  8vo.  Modena. 
1776.  Eyting,  De  consolidatione  vulnerum.  4to. 
Argent.  1770.  Moore,  On  the  process  of  nature  in 
the  filling  up  of  cavities,  healing  wounds,  &c.  4to. 
Lond.  1789.  Nannoni,  De  Similium  partium  corp. 
hum.  constit.  regeneratione.  (In  Roemeri  Delect. 
Opusc.  Ital.  vol.  i.)  Arnemann,  Versuche  neber 
die  Regeneration  an  lebenden  Thieren.  8vo.  Gotting. 
1782.  Murray,  De  redintegratione  partium,  &c. 
8vo.  Cassel,  1786.  Bell,  Discourses  on  wounds. 
8vo.  Edin.  1795—1812.  Balfour,  Obs.  on  Adhe- 
sion. 8vo.  Lond.  1815.  Stoll,  Ratio  Medendi,  pars 
v.  &  vii.8vo.  Vienna,  1768.  Hunter  on  the  Blood, 
Inflammation,  &c.  Bichat,  Anatomie  Gen.  Beclard, 
ditto.  Breschet,  Diet,  de  Med.  art.  Adherence. 
Cruveilhier,  Diet,  de  Med.  et  Chir.  Prat.  art. 
Adhesions.  Laennec,  De  1' Auscultation  Mediate, 
torn.  ii.  pp.  111.  et  seq.  Brande,  in  Phil.  Trans. 
1818.  Gendrin,  Hist.  Anat.  des  Infl.  passim. 
2  torn.  Paris,  1826.  Andral's  Pathological  Ana- 
tomy. Home  on  Ulcers.  8vo.  Lond.  1801. 

(Benjamin  Phillips,) 

ADIPOCERE,  from  adeps  and  cera:  a  term 
given  to  a  peculiar  fatty  matter,  somewhat  re- 
sembling spermaceti  in  appearance,  and  sup- 
posed to  partake  of  the  properties  of  fat  and 
wax.  In  the  year  1789,  Fourcroy  communi- 
cated to  the  Royal  Academy  of  Sciences  at 
Paris  a  curious  account  of  the  changes  sus- 
tained by  the  human  bodies  interred  in  the 
cemetery  of  the  Innocents  in  that  city;  some 
of  these  had  been  piled,  for  a  succession  of 
years,  closely  upon  each  other,  in  large  cavities 
containing  from  one  thousand  to  fifteen  hundred 


ADIPOSE  TISSUE. 


individuals.  One  of  these  graves,  opened  in 
Fourcroy's  presence,  had  been  full,  and  closed 
for  fifteen  years.  When  the  coffins  were  opened, 
the  bodies  appeared  shrunk  and  flattened,  and 
the  soft  solids  were  converted  into  a  brittle  cheesy 
matter,  which  softened  and  felt  greasy  when 
rubbed  between  the  fingers.  The  bones  were 
brittle ;  and  the  texture  of  the  abdominal  and 
thoracic  viscera  no  longer  discernible,  but 
lumps  of  fatty  matter  occupied  their  places. 

It  is  not  uncommon  to  find  masses  of  this 
adipocere  in  the  refuse  of  dissecting-rooms, 
especially  when  heaps  of  such  offal  are  thrown 
into  pits  and  wells,  and  suffered  gradually  to 
decay.  The  carcases  of  cats  and  dogs  and 
other  drowned  animals  also  often  exhibit  more 
or  less  of  a  similar  change ;  and  Dr.  Gibbes 
(Phil.  Trans.  1794)  found  that  lean  beef,  se- 
cured in  a  running  stream,  underwent  a  change 
into  fat  in  the  course  of  three  weeks.  Fat,  and 
the  adipose  parts  of  animals,  also  undergo  a 
change  in  appearance  and  composition  under 
similar  circumstances:  tallow  becomes  brittle 
and  pulverulent,  and  may  be  rubbed  between 
the  fingers  into  a  white  soapy  powder.* 

Gay  Lussac,  Chevreul,  and  some  other  emi- 
nent chemists,  conceive  that  muscular  fibre,  skin, 
&c.  is  not  convertible  into  adipocere, but  that  this 
compound  results  entirely  from  the  fat  originally 
present  in  the  substance,  and  that  the  fibrin 
is  completely  destroyed  by  putrefaction.  There 
are  cases,  however,  in  which  the  conversion 
of  muscle  and  of  fibrin  into  fat  can  scarcely 
be  doubted,  (Annals  of  Philosophy,  xii.  41,) 
though  the  propriety  of  applying  the  term  adipo- 
cere to  such  fatty  matter  may  be  questionable. 
The  action  of  very  dilute  nitric  acid  upon  some 
of  the  modifications  of  albumen  is  also  attended 
by  their  conversion  into  an  adipose  substance. 

The  chemical  properties  usually  ascribed  to 
adipocere  are  the  following:  it  fuses  at  a  tem- 
perature below  100°;  it  dissolves  in  boiling 
alcohol,  and  the  greater  portion  is  deposited  as 
the  solution  cools;  the  action  of  ether  resembles 
that  of  alcohol ;  it  is  saponified  by  the  fixed 
alkalies,  but  not  by  ammonia.  It  would  ap- 
pear, however,  from  Chevreul's  experiments, 
that  adipocere  is  not  a  mere  modification  of 
fat,  or  a  simple  product,  but  that  it  is  a  soap 
composed  of  margaric  acid  and  ammonia. 
These  combinations  of  adipose  substances  and 
their  further  chemical  history  will  be  given 
under  the  article  FAT. 

BIBLIOGRAPHY. — Fourcroy,Acad.Rle.des  Sciences 
de  Paris,  1787.  Gibbes,  Conversion  of  animal 
muscle  into  a  substance  resembling  spermaceti. 
Phil.  Trans.  1794.  Conversion  of  animal  sub- 
stances into  fatty  matter.  Phil.  Trans.  1795.  Vide 
also'Annules  de  Chimie,  t.  v.  154  ;  t.  viii.  17 — 72  ; 
Crell's  chemische  Annalen  for  1792  and  1794  :  and 
John's  Tabellcn.  1.  B.  p.  35. 

(  W.  T.  Brande.) 

*  If  a  portion  of  the  fatty  degeneration  of  the 
liver  be  immersed  for  some  time  in  water,  it  will 
furnish  an  excellent  specimen  of  adipocere.  The 
writer  of  this  note  had  lately  an  opportunity  of 
observing  the  process  of  the  conversion  of  a  large 
portion  of  liver  into  this  substance. — R.  B.  T. 


ADIPOSE  TISSUE.— (Lat.  Telaadiposa 
Fr.  tissu  adipeux,  tissu  graisseux,  Germ,  das 
Fttt,  Ital.  adipe. 

Many  of  the  old  anatomists,  as  Mondini, 
Berenger,  Vesalius,  and  Spigelius,  represent 
the  fat  (adeps  vel  pinguedo)  of  the  animal  body 
as  entirely  distinct  from  the  membrana  carnosa, 
or  cellular  membrane.  The  separate  existence 
of  a  proper  adipose  membrane,  however,  si- 
tuate between  the  skin  and  the  filamentous 
tissue,  or  membrana  carnosa,  was  first  taught 
by  Malpighi,  then  distinctly  maintained  by 
De  Bergen  and  Morgagni,  and  finally  demon- 
strated by  William  Hunter.  Collins,  James 
Keill,  and  other  anatomists  adopted  the  views 
of  Malpighi,  and  Haller  was  disposed  latterly 
to  imitate  De  Bergen  and  Morgagni,  in  assigning 
to  the  fat  of  the  animal  body  a  situation  dis- 
tinct from  that  of  the  cellular  membrane.  And 
in  this  country  the  independent  existence  of 
the  adipose  membrane  was  recognized  by 
Bromfield,  John  Hunter,  and  others. 

It  was  still,  however,  confounded  with  that 
of  the  filamentous  tissue  under  the  general 
name  of  cellular  membrane,  adipose  mem- 
brane, and  cellular  fat,  by  Winslow,  Dionis, 
Portal,  Sabatier,  Bichat,  and  Meckel,  and 
described  as  a  variety  or  modification  of  the 
cellular  membrane;  and  Blumenbach  considers 
it  as  a  secretion  into  that  membrane.  Its  dis- 
tinct existence  from  the  cellular  membrane  was 
finally  admitted  by  M.  Beclard,  and  its  anato- 
mical and  physiological  relations  as  well  as  its 
chemical  properties  have  been  since  minutely 
investigated  by  M.  Raspail. 

According  to  the  dissections  of  De  Bergen 
and  Morgagni,  the  demonstrations  of  Hunter, 
and  the  observations  of  M.  Beclard,  the  struc- 
ture of  the  adipose  membrane  consists  of 
rounded  packets  or  parcels  (pelotom)  separated 
from  each  other  by  furrows  of  various  depth,  of 
a  figure  irregularly  ovoidal,  or  spheroidal,  va- 
rying in  diameter  from  a  line  to  half  an  inch, 
according  to  the  degree  of  obesity  in  the 
part  submitted  to  examination.  Each  packet 
is  composed  of  small  spheroidal  particles  which 
may  be  easily  separated  by  dissection,  and 
which  are  said  to  consist  of  an  assemblage  of 
vesicular  bags  still  more  minute,  aggregated 
together  by  very  delicate  filamentous  tissue. 
These  were  originally  described  by  Malpighi 
under  the  name  of  membranous  sacculi,  and 
by  Morgagni  under  that  of  sacculi  pinguedi- 
nosi. 

The  appearance  of  these  ultimate  vesicular 
pouches  is  minutely  described  by  Wolff  in  the 
subcutaneous  fat,  and  by  Clopton  Havers*  and 
the  first  Monro  in  the  marrow  of  bones,  in 
which  the  two  last  authors  compare  them  to 
strings  of  minute  pearls.  If  the  fat  with  which 
these  vesicles  are  generally  distended  should 
disappear,  as  happens  in  dropsy,  consumption, 
chronic  dysentery,  and  other  wasting  diseases, 
the  vesicular  sacs  collapse,  their  cavity  is  obli- 
terated, and  they  are  confounded  with  the  con- 

*  Osteologia  Nova,  Lond.  1691,  and  Obs.  Nov. 
de  Ossibus,  Amst.  1731. 


ADIPOSE  TISSUE. 


tiguous  cellular  tissue  without  leaving  any  trace 
of  their  existence. 

Hunter,  however,  asserts  that  in  such  cir- 
cumstances the  cellular  tissue  differs  from  the 
tissue  of  adipose  vesicles  in  containing  no 
similar  cavities,  remarks  that  the  latter  is  much 
more  fleshy  and  ligamentous  than  the  fila- 
mentous tissue,  and  contends  that  though  the 
adipose  vesicles  are  empty  and  collapsed,  they 
still  exist.  When  the  skin  is  dissected  from 
the  adipose  membrane,  it  is  always  possible 
to  distinguish  the  latter  from  the  filamentous 
tissue,  even  if  it  contain  no  fat,  by  the  tough- 
ness of  its  fibres  and  the  coarseness  of  the  web 
which  they  make. 

The  distinguishing  characters  between  the 
cellular  or  filamentous  and  the  adipose  tissue 
may  be  stated  in  the  following  manner.  First, 
the  vesicles  of  the  adipose  membrane  are  closed 
all  round,  and,  unlike  the  cellular  tissue,  they 
cannot  be  generally  penetrated  by  fluids  which 
are  made  to  enter  them.  If  the  temperature 
of  a  portion  of  adipose  membrane  be  raised 
by  means  of  warm  water  to  the  liquefying 
point  of  the  contents,  they  will  remain  un- 
moved so  long  as  the  structure  of  the  vesicles 
is  not  injured  by  the  heat.  If  again  an  adi- 
pose packet  be  exposed  to  a  solar  heat  of  104° 
Fahrenheit,  though  the  fat  be  completely  lique- 
fied, not  a  drop  will  escape  until  the  vesicles 
are  divided  or  otherwise  opened,  when  it  ap- 
pears in  abundance.  The  adipose  matter, 
therefore,  though  fluid  or  semifluid  in  the 
living  body,  does  not,  like  dropsical  infiltra- 
tion, obey  the  impulse  of  gravity.  Secondly, 
the  adipose  vesicles  do  not  form,  like  cellular 
tissue,  a  continuous  whole,  but  are  simply  in 
mutual  contiguity.  This  arrangement  is  de- 
monstrated by  actual  inspection,  but  becomes 
more  conspicuous  in  the  case  of  dropsical  effu- 
sions, when  the  filamentous  tissue  interposed 
between  the  adipose  molecules  is  completely 
infiltrated  while  the  latter  are  entirely  unaf- 
fected. Thirdly,  the  anatomical  situation  of 
the  adipose  tissue  is  different  from  that  of  the 
filamentous  tissue.  The  former  is  found,  1st, 
in  a  considerable  layer  extended  immediately 
beneath  the  skin ;  2dly,  in  the  trunk  and  ex- 
tremities round  the  large  vessels  and  nerves ; 
3dly,  between  the  serous  and  muscular  tissues 
of  the  heart ;  4thly,  between  the  peritoneal 
folds  which  form  the  omentum  and  mesentery  ; 
5thly,  round  each  kidney;  and,  Gthly,  in  cer- 
tain folds  of  the  synovial  membranes  without 
the  articular  capsules. 

In  each  of  these  situations  it  varies  in  quan- 
tity and  physical  properties.  In  the  least  cor- 
pulent persons  a  portion  of  fat  is  deposited  in 
the  adipose  membrane  of  the  cheeks,  orbits, 
palms  of  the  hands,  soles  of  the  feet,  pulp  of 
the  fingers  and  toes,  flexures  of  the  joints, 
round  the  kidney,  beneath  the  cardiac  serous 
membrane,  and  between  the  layers  of  the  me- 
sentery and  omentum.  In  the  more  corpulent, 
and  chiefly  in  females,  it  is  found  not  merely 
in  these  situations,  but  extended  in  a  layer  of 
some  thickness,  almost  uniformly  over  the 
whole  person;  but  is  very  abundant  in  the 


neck,  breasts,  belly,  mons  Verier  is,  and  flexures 
of  the  joints. 

It  has  been  long  observed  that  the  subcu- 
taneous adipose  layer  presents  considerable 
differences  from  the  adipose  matter  found  be- 
tween the  folds  of  the  serous  membranes  ;  and 
the  older  anatomists,  aware  of  these  differences, 
distinguished  the  former  by  the  name  of  pin- 
ft uc do,  and  the  latter  by  that  of  xebuiti.  The 
subcutaneous  adipose  membrane  is,  when 
viewed  as  a  whole,  more  elastic,  softer,  and 
less  granular  than  the  omental  fat,  and  evi- 
dently presents  the  arrangement  of  vesicular 
bags  much  more  distinctly  than  the  omental. 
It  is  in  the  subcutaneous  adipose  membrane 
indeed,  almost  exclusively,  that  the  vesicular 
arrangement  can  be  recognized.  The  subcu- 
taneous cellular  fat  also  contains  a  greater 
quantity  of  oil  than  the  omental,  which  abounds 
chiefly  in  firm,  brittle,  granular  fat. 

The  situation  where  the  vesicular  structure 
of  the  adipose  membrane  is  most  easily  de- 
monstrated is  in  the  hips  between  the  skin 
and  the  gluteal  muscles,  and  at  the  flexures  of 
the  joints  generally.  In  the  former  situation 
especially,  the  constituent  fibres  of  the  vesi- 
cular bags  are  tough,  firm,  and  ligamentous, 
and  the  bags  themselves  are  large  and  distinct. 

It  is  a  remarkable  anatomical  character  of 
the  sebaceous  or  tallow-like  fat  that  its  distri- 
bution is  confined  chiefly  to  the  external  or 
commutual  surfaces  of  several  of  the  serous 
membranes;  and  this  arrangement  presents  a 
series  of  interesting  anatomical  analogies.  Thus 
sebaceous  fat  is  found  on  the  external  surface 
of  the  pleura  costalis,  between  it  and  the  inter- 
costal muscles,  and  between  the  layers  at  the 
posterior  and  anterior  mediastinum.  It  is  also 
found  between  the  cardiac  pericardium  and  the 
muscular  substance  of  the  heart,  especially 
around  the  vessels  of  the  organ.  In  some  of 
the  large  mammalia  even  this  circumstance  is 
connected  with  peculiar  anatomical  appear- 
ances. Thus,  in  the  heart  of  the  dolphin  ( del- 
p/iinus  tursio)  we  find  the  cardiac  pericardium 
formed  into  broad  prominent  fringes,  consisting 
each  of  two  folds  of  the  membrane,  between 
which  is  interposed  a  considerable  quantity  of 
sebaceous  fat.  In  the  same  manner  the  several 
amenta,  or  peritoneal  duplicatures  in  the  abdo- 
men, may  be  recognized  as  analogous  fringes 
containing  more  or  less  sebaceous  fat;  and  the 
omental  appendages  (appendices  epiploictz)  of 
the  colon  must  be  regarded  as  examples  of  the 
same  arrangement.  Lastly,  in  the  interior  of 
the  articular  capsules  we  find  the  synovial 
membranes  forming  large  prominent  fringes, 
which,  if  immersed  in  water,  show  to  what 
extent  they  are  made  to  recede  from  the  cap- 
sule and  bone,  and  forming  cavities  of  dupli- 
cation in  which  sebaceous  matter  is  contained. 
It  thus  appears  that  none  of  the  serous  mem- 
branes is  exactly  applied  either  to  the  parietes 
of  cavities  or  to  the  surface  of  the  contained 
organs,  but  that  they  form  intervals  on  their 
outer  or  attached  surfaces,  on  which  various 
quantities  of  sebaceous  fat  are  deposited.  In 
all  these  substance^  we  do  not  recognize  the 


58 


ADIPOSE  TISSUE. 


same  distinct  arrangement  of  an  appropriate 
organ,  but  simply  masses  of  adipose,  or  rather 
sebaceous  matter,  interposed  between  the  at- 
tached surface  of  the  serous  membranes  and 
the  adjoining  or  the  contained  organs. 

Fat  occurs  in  a  third  modification  in  the 
marrow  of  bones.  The  adipose  granules,  which 
are  soft,  whitish-yellow,  and  oleaginous,  are 
here  contained  in  a  peculiar  membrano-cellular 
web,  forming  numerous  vesicles,  which  may  be 
regarded  as  an  ultra-osseous  adipose  tissue.  It 
is  a  remarkable  proof  of  the  influence  of  the 
vital  principle  that  during  life  the  substance  of 
the  bones  is  never  tinged  with  this  animal  oil, 
but  the  moment  life  is  extinct,  the  marrow 
begins  to  transude  and  impart  to  the  bones  a 
yellow  tint  and  a  greasy  aspect. 

Fat,  though  chiefly  observed  to  occur  in  the 
bodies  of  animals,  is  nevertheless  not  confined 
solely  to  these  bodies.  Thus  not  only  do  va- 
rious kinds  of  oil  and  consistent  oleaginous 
matter  occur  in  certain  vegetables,  but  sub- 
stances similar  even  to  tallow  are  found  in 
some  vegetable  productions.  A  sort  of 
tallow  is  obtained  from  the  Valeria  Indie  a,  a 
forest-tree  of  the  camphor  family,  indigenous 
in  the  Indian  Archipelago.  In  a  species  of 
croton  indigenous  in  China,  namely,  the  croton 
sebiferum  of  Linnaeus,  the  stillingia  of  Mi- 
chaux,  or  tallow-tree,  the  seeds  are  covered 
with  a  quantity  of  fat,  bearing  so  close  a  re- 
semblance in  all  its  properties  to  tallow,  that  it 
is  used  by  the  Chinese  in  the  manufacture  of 
candles  ;  and  the  fruits  of  the  aleurites  triloba, 
a  native  of  the  Sandwicli  Islands,  of  the  same 
natural  family  with  the  croton,  are  the  candle- 
nuts  of  the  inhabitants  of  these  remote  regions. 

It  is  chiefly  in  the  subcutaneous  layer  that 
the  organization  of  the  adipose  membrane  has 
been  investigated.  The  constituent  vesicles  or 
bags  consist  of  firm,  tenacious,  ligamentous, 
gray,  or  whitish-gray  coloured  substance,  mu- 
tually united  by  means  of  delicate  filamentous 
tissue.  These  vesicles  or  sacs  receive  arterial 
and  venous  branches,  the  arrangement  of  which 
has  been  described  by  various  authors,  from 
Malpighi,  who  gave  the  first  accurate  account, 
to  Mascagni,  to  whom  we  are  indebted  for  the 
most  recent.  According  to  Malpighi,*  the 
bloodvessels  divide  into  minute  ramifications, 
to  the  extremities  of  which  are  attached  the 
membranous  sacs,  containing  the  globules  of 
fat  so  as  to  bear  some  resemblance  to  the  leaves 
attached  to  the  footstalks  of  trees.  These  ve- 
sicular or  saccular  arteries  are  afterwards  di- 
vided into  more  minute  vessels,  which  then 
form  upon  the  vesicular  sacs  a  delicate  vascular 
network.  According  to  Mascagni,  who  repre- 
sents these  vessels  in  accurate  delineations,  the 
furrow  or  space  between  each  packet  con- 
tains an  artery  and  vein,  which,  being  subdi- 
vided, penetrates  between  minute  grains  or  adi- 
pose particles,  of  which  the  packet  is  composed, 
and  furnishes  each  component  granule  with  a 
small  artery  and  vein.  The  effect  of  this  ar- 


rangement is  that  each  individual  grain  or 
adipose  particle  is  supported  by  its  artery  and 
vein  as  by  a  footstalk  or  peduncle,  and  those  of 
the  same  packet  are  kept  together  not  only  by 
contact,  but  by  the  community  of  ramifications 
from  the  same  vessel.  These  grains  are  so 
closely  attached  that  Mascagni,  who  examined 
them  with  a  good  lens,  compares  them  to  a 
cluster  of  fish-spawn.  Grutzmacher  found 
much  the  same  arrangement  in  the  grains  and 
vesicles  of  the  marrow  of  bones.* 

It  has  been  supposed  that  the  adipose  tissue 
receives  nervous  filaments;  and  Mascagni  con- 
ceives he  has  demonstrated  its  lymphatics.  Both 
points,  however,  are  so  problematical,  that  of 
neither  of  these  tissues  is  the  distribution  known. 

The  substance  contained  in  these  vesicles  is 
entirely  inorganic.  Always  solid  in  the  dead 
body,  it  has  been  represented  as  being  fluid 
during  life,  by  Winslow,  Haller,  Portal,  Bichat, 
and  most  authors  on  anatomy.  The  last  writer, 
indeed,  states  that  under  the  skin  it  is  more 
consistent,  and  that  in  various  living  animals 
he  never  found  it  so  fluid  as  is  represented. 
The  truth  is  that  in  the  human  body,  and  in 
most  mammiferous  animals  during  life,  the  fat 
is  neither  fluid  nor  semifluid.  It  is  simply 
soft,  yielding,  and  compressible,  with  a  slight 
degree  of  transparency,  or  rather  translucence. 
This  is  easily  established  by  observing  it  during 
incisions  through  the  adipose  membrane,  either 
in  the  human  body  or  in  the  lower  animals. 

The  internal  or  sebaceous  fat,  however,  espe- 
cially that  interposed  between  the  fat  of  the 
serous  membranes,  is  much  more  consistent  and 
solid.  The  reason  of  these  differences  will  be 
understood  from  what  is  now  to  be  stated  re- 
garding the  proximate  principles  of  animal  fat. 

The  microscopical  and  atomical  structure  of 
fat  has  recently  formed  the  subject  of  investi- 
gation by  M.  Raspail.f  By  placing  a  portion 
of  lacerated  fat  upon  a  sieve,  with  an  earthen 
vessel  below  it,  and  directing  upon  it  a  stream 
of  water,  numerous  amylaceous  granules  are  de- 
tached and  pass  through  the  sieve,  and  after 
foiling  to  the  bottom  of  the  water  afterwards 
rise  to  the  surface,  in  the  form  of  a  crystalline 
powder,  as  white  as  snow.  When  these  par- 
ticles are  collected  by  scumming,  and  dried, 
they  form  a  starchy  powder,  though  soft  and 
somewhat  oleaginous  to  the  touch,  and  which 
does  not  reflect  the  light  in  a  manner  so  cry- 
stalline as  an  amylaceous  deposit  does. 

According  to  M.  Raspail,'  when  examined 
microscopically,  these  granules  present  forms 
and  dimensions  varying  in  different  animals, 
in  the  same  animal  and  even  in  animals  of  dif- 
ferent ages,  but  in  all  clearly  resembling  grains 
of  fecula.  In  the  human  body  these  particles 
are  polyhedral  and  not  susceptible  of  isolation. 
As  they  are  more  fluid  also  than  in  other 
animals,  it  is  necessary  to  immerse  the  portion 
subjected  to  examination  in  nitric  acid  or 
liquor  potasses,  either  of  which  has  the  effect 
of  consolidating  the  inclosed  or  central  portion 


*  De  Qmento,   Pinguedine,  et  Adiposis  Ductibus, 
p.  41. 


*  De  Ossium  Medulla,  Lips.  1758. 
t  Repertoire  Generale  d'Anat.  1827. 


ADIPOSE  TISSUE. 


of  each  granule,  and  disintegrating  the  granules 
by  the  contraction  of  chemical  agency.  The 
borders  of  these  granules  appear  by  refracted 
light  a  little  fringed — an  effect  which  M.  Ras- 
pail  attributes  to  the  corrosive  action  of  the 
nitric  acid. 

When  magnified  to  100  diameters,  they  ap- 
pear like  irregular  hexaedral  or  pentaedral 
bodies,  from  two  to  four  lines  in  diameter,  and 
all  accurately  fitted  or  conjoined  to  each  other. 
The  actual  diameter  of  these  granules  in  the 
adult  human  subject  varies  according  to  Ras- 
pail  from  .00117  to  .00562  of  an  English  inch. 
In  youth  and  infancy  they  are  stated  to  be  still 
smaller. 

The  chief  point  to  bear  in  remembrance  is 
that  the  adipose  tissue  consists  of  two  distinct 
parts,  one  a  vital  organic  and  secreting  part, 
the  other  an  inorganic  and  secreted  product, 
which  is  void  of  vital  principle.  The  chemical 
constitution  of  fat  has  been  investigated  by 
Chevreul,  Braconnot,  and  more  recently  by 
M.  Raspail.  According  to  the  researches  of 
M.  Chevreul  fat  consists  essentially  of  two 
proximate  principles,  stearine  (arsae.^,  sebum, 
sapo,j  and  elainc,  (gXatov,  oleum.}  The  former 
is  a  solid  substance,  colourless,  tasteless,  and 
almost  inodorous,  soluble  in  alcohol,  and  pre- 
serving its  solidity  at  a  temperature  of  176° 
Fahrenheit.  Elaine,  on  the  contrary,  though 
colourless,  or  at  most  of  a  yellow  tint,  and 
lighter  than  water,  is  fluid  at  a  temperature  of 
from  63o  to  65°  Fahrenheit,  and  is  greatly 
more  soluble  in  alcohol.  To  the  presence  of 
stearine  in  a  large  proportion,  the  intra-serous 
sebaceous  fat  owes  its  solidity  and  firmness ; 
whereas  the  elasticity  and  softness  of  the  sub- 
cutaneous adipose  tissue,  and  the  marrow, 
depend  upon  the  predominance  of  elaine. 

It  is  farther  important  to  attend  to  the  ele- 
mentary composition  of  fat.  Each  variety  of 
fat  consists  of  carbon,  hydrogen,  and  oxygen ; 
and  a  few,  as  hog's  lard,  blubber,  nut  oil,  and 
almond  oil,  contain  a  small  trace  of  azote. 
The  proportion  of  the  carbon  is  greatest  and 
varies  in  general  from  7-10ths  to  4-5ths  of  the 
whole.  The  proportion  of  hydrogen  varies 
from  l-10th  to  l-5th.  That  of  oxygen  varies 
from  four  or  five  parts  in  the  hundred  to 
12  and  13.  It  appears,  therefore,  that  fat  and 
each  of  its  constituent  principles  are  a  highly 
carbonaceous  animal  substance. 

Little  doubt  can  be  entertained  that  animal 
fat  is  the  result  of  a  process  of  secretion.  But 
it  is  no  easy  matter  to  determine  the  mode  in 
which  this  is  effected.  Previous  to  the  time 
of  Malpighi  it  was  a  very  general  opinion  that 
the  blood  exuding  from  the  vessels  was  con- 
verted into  adipose  matter.  This  fancy  was 
refuted  by  Malpighi,  who,  departing,  however, 
from  strict  observation,  imagined  a  set  of  ducts, 
(ductus  adiposi)  issuing  from  glands,  in  which 
he  conceived  the  fat  to  be  elaborated  and  pre- 
pared. To  this  fancy  he  appears  to  have  been 
led  by  his  study  of  the  lymphatic  glands,  and 
inability  to  comprehend  how  the  process  of 
secretion  could  be  accomplished  by  arteries 
only.  The  doctrine,  though  embraced  by 
Perrault,  Collins,  and  Hartsoecher,  was  over- 


thrown by  the  strong  arguments  which  Ruysch 
deduced  from  his  injections;  and  Malpighi 
afterwards  acknowledged  its  weakness  and  re- 
nounced it.  In  short,  neither  the  glands  nor 
the  ducts  of  the  adipose  membrane  have  ever 
been  seen,  unless  we  admit  the  testimony  of 
the  Members  of  the  Parisian  Academy,  who 
state  that  they  saw  them  in  the  civet  cat,  and 
to  this  we  must  oppose  the  fact  that  Morgagni, 
by  anatomical  evidence,  disproved  their  ex- 
istence. Winslow,  though  willing  to  adopt  the 
notion  of  Malpighi,  admits,  nevertheless,  that 
the  particular  organ,  by  which  the  fat  is  sepa- 
rated from  the  blood,  is  unknown.  Haller, 
on  the  contrary,  aware  of  the  permeability  of 
the  arteries,  and  inferring  from  the  phenomena 
of  injections  either  of  watery  liquors  or  melted 
tallow,  their  direct  communication  with  the 
cells  of  the  adipose  tissue,  and  trusting  to  the 
testimony  of  Matpighi,  Ruysch,  Glisson,  and 
Morgagni,  that  fat  exists  in  the  arterial  blood, 
saw  no  difficulty  in  the  doctrine  of  secretion, 
or  rather  of  a  process  of  separation  ;  and  upon 
much  the  same  grounds  is  this  opinion  adopted 
by  Portal.  Bichat,  again,  contends  that  no  fat 
can  be  recognized  in  the  arterial  blood,  and 
justly  adduces  the  fact,  that  none  can  be  dis- 
tinguished in  blood  drawn  from  the  temporal 
artery.  To  the  accuracy  of  this  fact  I  can 
bear  direct  testimony,  having  repeatedly  ex- 
amined with  the  view  of  recognizing  the  buffy 
coat,  and  detecting  oily  particles,  blood,  which 
I  had  drawn  from  this  vessel, — the  latter  sub- 
stance invariably  without  success.  In  wounds 
in  the  human  body  during  life,  and  living 
animals,  oily  particles  may  be  seen  floating  on 
the  surface  of  the  blood ;  but  these,  it  may  be 
said,  proceed  from  the  division  of  the  adipose 
vesicles;  and  hence  it  has  been  inferred  that 
the  arterial  blood  contains  no  adipose  or  olea- 
ginous matter. 

It  may  be  doubted,  however,  whether  facts 
of  this  kind  are  adequate  to  prove  whether 
adipose  or  oily  matter  does  not  naturally  exist 
in  the  blood,  and  both  from  the  experiments 
of  Chevreul,  and  those  of  Lecanu  and  Boudet 
it  appears  that  small  quantities  of  adipose  or 
puriloid  matter  may  be  obtained  from  this 
fluid.  M.  Chevreul,  for  example,  shows  that 
fatty  matter  may  be  obtained  from  the  fibrine 
of  arterial  blood  ;  and  from  a  series  of  elabo- 
rate and  accurate  experiments,  estimates  the 
quantity  of  fatty  matter  in  fibrine  at  from  four 
to  five  per  cent.*  Lecanu  and  Boudet  have 
also  recently  shown  that  crystals  of  pearly- 
coloured  matter  having  the  characters  of  an 
adipose  substance  exist  in,  and  may  be  ob- 
tained in  small  proportion  from  the  serum  of 
the  blood  .f  These  inferences  apply,  according 
to  the  authors,  to  blood  in  its  healthy  state. 

In  certain  states  of  the  system  the  blood 
drawn  from  the  veins  has  presented  serum  of 
an  opaque  or  milky  appearance,  and  which 
has  been  proved  to  depend  on  the  presence  of 
adipose  or  oleaginous  matter.  Thus,  indepen- 
dent of  opaque  or  milky  serum  noticed  by 

*  Journal  de  Physiol.  torn.  iv.  p.  119. 
t  Journal  dc  Pharmacia,  1830-33. 


60 


ADIPOSE  TISSUE. 


Schenke,  Tulpius,  Morgagni,  and  others, 
Hewson  and  several  cotemporary  observers 
remarked  instances  of  opacity  and  milkiness 
of  the  serum  of  the  blood,  and  from  ocular 
inspection  as  well  as  experiment  and  obser- 
vation, inferred  that  these  appearances  arose 
from  the  presence  of  oil  in  the  blood  or  its 
serum.  Soon  after  Dr.  Gregory,  in  his  Con- 
spectus, or  View  of  the  Institutions  of  Medicine, 
was  led  to  infer  apparently  from  the  fact  stated 
by  Hewson,  that  in  persons  in  whom  the 
serum  was  opaque  or  milky,  this  depends  on 
the  presence  of  fat  which  is  undergoing  ab- 
sorption, or  resumption  into  the  system.  This 
representation,  however,  was  entirely  conjec- 
tural ;  and  no  direct  proof  of  the  fact  that  oil 
does  exist  in  certain  states  in  the  venous  blood 
was  given  till  Dr.  Traill,  in  1821  and  1823, 
furnished  accurate  chemical  evidence  on  the 
point.  The  inferences  of  Dr«.  Traill  have  been 
since  confirmed  by  the  experiments  of  Dr. 
Christison,  who  found  that  milky  serum  con- 
tains oleaginous  or  adipose  matter,  consisting  of 
the  two  adipose  principles  elairie  and  stearine.* 

The  general  conclusions,  therefore,  that  may 
be  deduced  from  the  facts  now  stated  are  that 
in  the  healthy  state  adipose  matter  in  small 
proportion  exists  in  the  fibrine  of  the  blood, 
and  in  a  still  smaller  portion  in  the  serum  ; 
and  that  in  certain  morbid  conditions  of  the 
system,  in  which  there  is  any  process  of  mis- 
nutrition  or  paratrophia,  oily  matter  in  con- 
siderable quantity  may  be  found  in  the  blood, 
either  in  consequence  of  absorption  or  non- 
deposition. 

To  account,  however,  for  the  secretion  of 
adipose  matter,  it  is  not  absolutely  requisite  to 
prove  that  oleaginous  or  adipose  matter  exists 
in  the  circulating  fluid.  Even  were  it  ascer- 
tained that  oil  or  adipose  matter  does  not  exist, 
or  cannot  be  detected  in  any  of  the  elements 
of  healthy  blopd,  the  fact  would  not  form  a 
stronger  argument  against  its  formation  from 
that  fluid,  than  in  the  case  of  several  other 
principles  which  enter  into  the  composition 
of  the  animal  tissues,  and  which  nevertheless 
do  not  exist  in  the  blood.  Thus  neither  gela- 
tine, which  exists  abundantly  in  skin,  tendon, 
cartilage,  ligament,  and  bone, — nor  osmazome, 
which  is  found  in  muscle,  are  contained  in 
healthy  blood.  But  we  know  that  the  chemical 
element  of  these  substances  exist  in  the  blood, 
and  we  farther  know  that  gelatine  consists  very 
nearly  of  the  same  chemical  elements  as  albu- 
men ;  and  we  must  infer,  therefore,  that  it  is 
the  faculty  of  the  living  tissues  or  vessels  to 
arrange  these  elements  in  that  manner  and 
proportion  in  which  they  may  constitute  re- 
spectively gelatine  and  osmazome.  The  same 
reasoning  may  be  applied  to  explain  the  for- 
mation of  fat  in  the  adipose  tissue.  Its  ele- 
ments already  exist  in  the  blood,  and  the  living 
agency  of  the  tissue  seems  all  that  is  requisite 
to  effect  its  deposition.  Its  composition  and 
history  would  also  show  that  it  is  a  secreted 
product  which  consists  of  superfluous  chemical 

*  Edin.  Med.  and  Sure.  Journal,  vol.  xxxiii. 
P.  274. 


elements  not  required  in  the  formation  of  the 
albuminous  and  gelatinous  tissues. 

On  this  subject  the  interesting  experiments 
of  Berard*  and  Dobereinerf  may,  perhaps,  fur- 
nish some  intelligible  means  of  illustration. 
The  former  chemist  found  that  by  mixing  one 
measure  of  carbonic  acid,  ten  measures  of 
carburetted  hydrogen,  and  twenty  of  hydrogen, 
and  transmitting  the  mixture  through  a  red-hot 
tube,  he  procured  artificially  several  white 
crystals  which  were  insoluble  in  water,  soluble 
in  alcohol,  and  fusible  by  heat  into  an  oily 
fluid.  The  latter  chemist  prepared  a  similar 
substance  from  a  mixture  of  coal-gas  and  aque- 
ous vapour. 

It  may  therefore  be  inferred  that  while  ani- 
mal fat  is  chiefly  a  combination  of  bicarbonated 
hydrogen  with  oxygen,  or,  in  other  words,  a 
highly  carburetted  hydrate  of  oxygen,  and  con- 
tains either  little  or  no  azote,  it  is  the  animal 
substance  which  makes  the  nearest  approach 
in  chemical  constitution  to  the  vegetable  prin- 
ciples. So  close,  indeed,  is  this  approxima- 
tion that  Raspail  thinks  it  may  be  in  this  re- 
pect  compared  with  starch;  and  as  the  different 
forms  of  fecula  are  prepared  by  the  vegetable 
tissues  for  the  nutritious  stores  of  the  vegetable 
during  the  process  of  development,  he  ob- 
serves that,  in  like  manner,  fat  is  deposited 
whenever  the  nutritious  function  is  in  excess 
in  the  animal  organs. 

It  was  a  singular  fancy  of  Fourcroy  that 
the  deposition  of  fat  in  animal  bodies  was  in- 
tended as  a  sort  of  vent  for  the  superfluous 
and  unnecessary  proportion  of  hydrogen,  since 
the  idea  is  at  variance  with  chemical  facts ;  and 
it  is  not  less  singular  that  such  a  hypothesis 
should  receive  any  countenance  from  Blumen- 
bach.  Carbon  is  the  principle  which  predo- 
minates most  largely  in  fat ;  and  if  any  atten- 
tion is  to  be  given  to  such  views,  the  adipose 
tissue  ought  to  be  regarded  as  the  outlet  for 
superfluous  carbonaceous  matter,  or  at  least 
carbonaceous  matter  in  a  much  larger  pro- 
portion than  hydrogen  and  oxygen.  The  pro- 
per physiological  view,  however,  of  this  ques- 
tion appears  to  be, — that  as  the  tissues  of  the 
animal  body  consist  chiefly  of  carbon,  hy- 
drogen, oxygen,  and  azote  united  in  variable 
proportions,  and  as  most  of  these  tissues  either 
contain  or  seem  to  require  azote,  the  adipose 
appears  to  be  destined  to  receive  whatever 
carbon,  hydrogen,  and  oxygen,  are  not  re- 
quired to  be  united  with  the  azote,  in  the  forma- 
tion of  the  albuminous,  the  gelatinous,  or  the 
albumino-gelatinous  tissues. 

On  the  mechanism  of  the  deposition  of  fat 
we  possess  no  exact  information.  But  various 
facts  may  tend  to  throw  some  light  on  the  cir- 
cumstances under  which  it  takes  place,  and 
the  history  of  the  state  of  the  adipose  tissue  at 
different  periods  of  life  is  instructive. 

In  the  foetus  the  adipose  tissue  contains  a 
sort  of  whitish,  solid,  granular  matter,  which 
resembles  adipocere  rather  than  genuine  fat. 


*  Ann.  de  Chimic,  1817,  t.  v.  p.  290. 
t  Zur    Pncumatischcn  Phytochcmie,    8vo.  Jena. 
1822. 


ADIPOSE  TISSUE. 


61 


Thus  it  is  less  oleaginous,  and  more  brittle 
and  friable  than  true  fat.  In  the  infant  this 
layer  continues  the  same  in  quantity,  but  a  little 
more  oleaginous,  till  the  period  at  which  the 
individual  begins  to  exert  the  muscles  of  loco- 
motion. The  fat  then  rapidly  diminishes  in 
quantity,  and  after  the  child  has  begun  to 
walk  and  run,  the  fat  has  almost  entirely  dis- 
appeared from  most  parts  of  the  adipose  tissue, 
except  the  orbits,  cheeks,  neck,  buttocks  and 
the  flexures  of  the  joints ;  but  even  in  these 
regions  it  is  much  less  abundant  and  much 
more  consistent. 

The  marrow  presents  similar  changes.  The 
bones  of  the  foetus  are  void  of  a  distinct  me- 
dullary canal,  and  present  merely  a  reddish, 
homogeneous,  vascular  pulp,  some\vhat  con- 
sistent, but  presenting  soft  compressible  por- 
tions. This  state  continues  some  time  after 
birth.  As  the  individual  passes  from  infancy 
to  childhood,  the  interior  of  the  bone  is  formed 
into  cancelli,  adipose  or  oleaginous  matter  is 
deposited  in  the  intra-osseous  tissue  within 
the  cancelli,  and  as  the  vessels  of  the  medullary 
membrane  gradually  mould  the  medullary 
canal,  this  oleaginous  matter  is  most  abun- 
dantly deposited  in  the  interior  of  the  cylin- 
drical bones.  The  marrow,  however,  is  much 
less  oleaginous,  and  more  like  a  pulpy  paste 
than  it  is  in  the  adult. 

During  the  periods  of  boyhood  and  youth 
fat  continues  very  sparing  in  the  adipose  tissue, 
and  especially  in  the  male  sex.  After  puberty, 
however,  it  becomes  more  abundant,  especially 
in  females.  After  this  period  the  deposition 
of  fat  depends  more  or  less  on  the  habits  of 
the  individual,  as  to  eating  and  drinking  and 
corporeal  exertion.  In  general  the  deposition 
of  fat  becomes  more  copious  and  general  after 
the  age  of  forty  or  forty-two  than  previously. 

From  these  several  facts  it  appears  to  result 
that  fat  is  to  be  regarded  as  a  secretion  by  the 
capillary  vessels  of  the  adipose  tissue  from  the 
blood,  and  that  the  tissue  and  its  vessels  are 
to  be  distinguished  from  the  fat  or  the  matter 
secreted  in  the  relation  of  vital  agents  and 
organic  products.  Upon  the  whole  the  idea 
of  Haller  as  modified  by  Mascagni  regarding 
the  origin  of  the  fat  appears  to  be  the  most 
probable,  viz.  that,  while  the  arteries  secrete 
an  imperfectly  formed  oily  fluid,  the  thinner 
parts  are  absorbed  either  by  lymphatics  or  by 
veins,  and  the  residue  is  left  in  a  more  con- 
sistent and  solid  form. 

I  think,  in  conclusion,  that,  taking  all  the 
circumstances  already  stated  into  consideration, 
it  may  be  inferred  that  adipose  matter,  or  its 
constituent  elements  exist  in  the  blood,  chiefly 
as  complementary  elements  of  the  albuminous, 
gelatinous,  osmazomatous,  or  gelatino-albu- 
minous  principles  employed  in  the  nutrition  of 
the  several  tissues ;  and  that,  as  the  carbon, 
hydrogen,  oxygen,  and  azote  are  employed  in 
the  formation  of  the  latter  tissues,  the  great 
excess  of  carbon,  and  the  smaller  excess  of  hy- 
drogen and  oxygen,  not  employed  in  the  for- 
mation of  these  tissues  are  arranged  by  the 
capillaries  in  such  proportions  as  to  form  adi- 
pose matter;  and  that  this  adipose  matter, 


though  fluid,  when  first  formed,  becomes  more 
consistent  and  fixed  after  deposition  in  its 
appropriate  tissues. 

The  pathological  conditions  of  the  ad i pom: 
tissue. 

\.  Inflammation. — From  various  facts,  and 
especially,  observing  the  phenomena  of  certain 
cases  of  what  have  been  denominated  diffuse 
inflammation  of  the  cellular  membrane,  1  for- 
merly inferred  that  the  peculiar  phenomena  of 
certain  intense  and  malignant  forms  of  this 
disorder,  depend  on  inflammation  not  of  the 
cellular  membrane,  but  of  the  adipose  tissue. 
This  conjecture  I  have  since  had  opportunities 
of  completely  verifying  as  to  certain,  if  not  the 
majority  of  cases  of  diffuse  inflammation. 

a.  In  cases  of  diffuse  inflammation  affecting 
the  arm,  the  inflammation  has  spread  along 
the  adipose  membrane,  producing  sero-puru- 
lent  suppuration  and  sloughs  of  the  adipose 
tissue.  In  cases  of  inflammation  at  the  verge 
of  the  anus,  the  disease  spreads  along  in  the 
same  manner,  and  affects,  almost  exclusively, 
the  adipose  tissue  around  the  anus  and  rectum, 
and  along  the  gluttei  muscles.  It  is  in  the 
same  manner  that  the  adipose  cushion,  with 
which  the  bloodvessels  are  surrounded,  is  oc- 
casionally the  seat  of  a  species  of  bad  inflam- 
matory action  terminating  in  fetid  and  sloughy 
suppuration. 

That  these  forms  of  diffuse  inflammation 
truly  depend  on  inflammation  of  the  adipose 
membrane,  I  must  further  maintain,  from  the 
fact  that  the  disease  occurs  not  only  in  the  ex- 
ternal adipose  cushion,  but  in  the  internal  or 
sebaceous  fat.  I  have  seen  an  example  of  in- 
flammation in  the  adipose  cushion  surrounding 
the  left  kidney,  in  which  the  whole  of  this 
substance  was  converted  into  an  ash-coloured, 
fetid,  semifluid  pulp,  mixed  with  shreddy  fila- 
ments, and  in  which  this  suppurative  slough- 
ing process  had  opened  a  passage  from  the  fat 
of  the  left  kidney  into  the  interior  of  the  trans- 
verse arch  of  the  colon.  The  instance  of  in- 
flammation and  subsequent  mortification  of  the 
adipose  membrane  surrounding  both  kidneys, 
detailed  by  Dr.  Thomas  Turner,  in  the  fourth 
volume  of  the  Transactions  of  the  College  of 
Physicians  in  London,  is  an  example  of  the  same 
species  of  disease.  In  the  case  witnessed  by  my- 
self, the  disease  gave  rise  to  the  usual  symptoms 
said  to  attend  diffuse  inflammation.  Though 
no  great  degree  of  pain  was  felt,  the  pulse  was 
quick  and  small,  the  tongue  brown  and  dry, 
the  countenance  dingy  and  lurid,  and  the  eyes 
heavy,  the  bowels  difficult  to  be  affected  by 
medicine,  the  urine  scanty  and  high-coloured, 
and  at  length  suppressed  ;  and  the  patient, 
after  muttering  delirium  and  typhomania  on  the 
second  day  of  the  attack,  with  subsultus  tendi- 
num,  passed  into  a  comatose  state,  which  ter- 
minated on  the  fourth  day  in  death. 

h.  This  doctrine  further  does  not  rest  upon 
evidence  deduced  from  the  mere  symptomatic 
characters  of  the  disorder.  In  fatal  instances 
of  diffuse  inflammation,  we  find  the  adipose 
membrane  not  only  partially  mortified  and 
suppurated,  but  that  part  of  it  adjoining  to  the 
skin  and  to  the  bloodvessels  very  much  loaded, 


62 


ADIPOSE  TISSUE. 


with  injected  vessels  containing  dark-coloured 
blood. 

c.  It  is  chiefly  in  the  corpulent,  either  by 
habit  or  by  age,  that  this  disease  assumes  its 
most  exquisite,  intense,  and  unmanageable 
forms.  In  persons  of  this  description,  who  it 
is  matter  of  common  observation  are  generally 
not  only  plethoric  but  bloated,  and  liable  to 
imperfect  circulation,  and  disorders  of  the  cir- 
culation and  secretions  generally,  and  in  whom 
very  slight  causes  often  induce  serious  disor- 
ders, the  adipose  tissue  appears  to  lose  a  great 
proportion  of  the  small  degree  of  vital  energy 
which  it  possesses,  and  the  more  abundant  its 
secreted  product  is,  the  less  active  are  its  vessels 
and  the  inherent  properties  of  the  membrane. 
In  consequence  of  this  greatly  impaired  energy, 
slight  causes,  as  cold,  injury,  punctures,  &c. 
produce  suddenly  a  complete  loss  of  circula- 
tion and  action  in  the  tissue ;  for  it  is  not  in- 
creased but  diminished  action ;  and  this  im- 
paired energy  continues,  until  the  natural  func- 
tions of  the  tissue  become  extinct.  It  is  thus 
that  the  secreted  or  inorganic  matter  of  the 
adipose  tissue  becomes,  as  it  were,  a  cause  of 
strangulation  of  the  tissue  itself,  or  at  least 
leads  so  directly  to  suppress  the  energies  of  its 
organic  part,  that  it  is  incapable  of  resisting 
morbific  agents  of  ordinary  power,  and  hence 
the  organic  part  either  may  be  smitten  with 
immediate  death  or  is  very  easily  made  to 
assume  a  very  low  and  imperfect  form  of  mor- 
bid action,  which  speedily  terminates  in  death. 

On  this  subject  it  is  further  proper  to  ob- 
serve that  Mr.  Bromfield,  surgeon  to  St. 
George's  Hospital,  who  sixty  years  ago  main- 
tained the  distinct  characters  and  situation  of 
the  adipose  membrane  from  the  cellular,  taught 
also  that  the  former  was  liable  to  inflammation, 
but  erroneously  imagined  that  this  inflamma- 
tion was  of  the  circumscribed  kind  only.* 

2.  Hemorrhage. — Effusion  of  blood  into  the 
adipose  tissue  is  not  very  common.     It  is  ob- 
served in   the   same   circumstances  nearly  in 
which  it  occurs  in  the  filamentous  tissue.  Thus 
it  has  been  seen  in  land  and  sea-scurvy.     Hux- 
harn  observed  it  in  fevers  with  petechial  erup- 
tions.    And  Cleghorn  states  that  one  of  the 
appearances  after  death  in  the  continuous  and 
malignant  tertians  of  Minorca  was  extravasa- 
tion of  blood  in  the  form  of  black  patches  in 
the  adipose  layer  of  the  mesentery,  omentum, 
and  colon. 

3.  Excessive  deposition. — In  certain  subjects, 
and  in  peculiar  circumstances,  the  quantity  de- 
posited is  enormous.     The  average  weight  of 
the  human  subject  at  a  medium  size  is  about 
160  pounds,   or  between  eleven  and  twelve 
stones.     Yet  instances   are   on   record   of  its 
attaining,  by  deposition  of  fat  in  the  adipose 
membrane,  the  extraordinary  weight  of  510  and 
600  pounds,  or  from  thirty-five  to  forty  stones. 
Cheyne  mentions  a  case  in  which  the  weight 
was  448  pounds,  equal  to  thirty-two  stones. 
In  the  Philosophical  Transactions  are  recorded 
two  cases  of  persons  so  corpulent,  that  one 
weighed  480  pounds  and  another  500  pounds. 

*  Chirurgical  Observations,  vol.  i.  p.  94. 


And  the  Breslau  Collections  contain  cases  in 
which  the  human  body  weighed  580  and  600 
pounds. 

In  females  and  in  eunuchs  it  is  more  abun- 
dant than  in  males ;  in  females  deprived  of  the 
ovaries  it  is  more  abundant  than  in  those  pos- 
sessed of  these  organs ;  and  it  is  well  known 
that  sterility  is  frequent  among  the  corpulent  of 
both  sexes.  In  some  circumstances  this  accu- 
mulation may  be  so  great  as  to  constitute  dis- 
ease, (polysarcia  adiposa  of  several  nosolo- 
gists);  and  in  other  circumstances  the  deposi- 
tion of  fat  is  a  means  which  the  secreting 
system  seems  to  employ  to  relieve  fulness  and 
tension  of  the  vessels,  and  if  not  to  cure,  at 
least  to  obviate  morbid  states  of  the  circula- 
tion. (Parry.)  Accumulations  of  fat  are  said 
to  take  place  in  some  animals  in  a  few  hours 
in  certain  states  of  the  atmosphere.  During 
a  fog  of  twenty-four  hours  continuance,  thrushes, 
wheat-ears,  ortolans,  and  red-breasts  are  report- 
ed to  become  so  fat  that  they  are  unable  to  fly 
from  the  sportsman.  (Bichat.) 

4.  Extreme  diminution. — The  diminution  or 
disappearance  of  fat  is  much  more  frequent 
than  its  extraordinary  abundance.  This  dimi- 
nution is  said  to  depend  on  one  or  other  of  the 
following  causes.  1st.  Long  abstinence,  as  in 
fasting,  and  the  periodical  sleep  of  dormant 
animals  ;  2d,  organic  diseases,  as  consumption, 
cancer,  disease  of  the  liver,  of  the  heart,  ulce- 
ration  of  the  intestines,  &c. ;  3d,  purulent  col- 
lections or  secretions ;  4th,  leucophlegmatic 
and  dropsical  states ;  5th,  gloomy  and  melan- 
choly thoughts  or  passions ;  6th,  long  and  un- 
interrupted effort  of  the  intellectual  powers ; 
7th,  preternatural  increase  of  the  natural  evacu- 
ations, as  in  cholera,  diarrhoea,  diabetes,  &c. 
mucous  discharges,  especially  from  the  pulmo- 
nary and  intestinal  membranes,  as  in  chronic 
catarrh,  inflammation  of  the  intestines,  and 
dysentery ;  8th,  long  and  intense  heat,  whether 
natural,  as  during  hot  summers,  or  artificial,  as 
in  furnaces,  hot-houses,  &c. ;  9th,  running, 
riding,  and  every  species  of  fatiguing  exercise 
long-continued,  as  is  exemplied  in  the  case  of 
grooms  at  Newmarket,  Doncaster,  &c. ;  10th, 
states  of  long  disease,  not  organic;  llth,  night- 
watching  and  want  of  sleep  in  general;  12th, 
immoderate  use  of  spirituous  liquors;  13th, 
habit  of  eating  bitter  and  spiced  or  acid 
aliments. 

Yet  even  in  these  states  the  fat  of  the  animal 
body  is  seldom  entirely  wasted.  In  several 
organic  diseases,  in  which  great  emaciation 
takes  place,  a  considerable  quantity  of  fat  is 
always  found  in  the  orbits  behind  the  eyeball, 
round  the  substance  of  the  heart,  around  the 
kidneys,  in  the  colon,  and  in  the  mesentery 
and  omentum.  Thus  one  or  both  lungs  may 
be  extensively  occupied  by  tubercles  and  indu- 
rated portions  giving  rise  to  the  usual  symptoms 
of  pulmonary  consumption  terminating  fatally, 
yet  without  removing  the  fat  from  the  subcuta- 
neous layer  of  the  chest  and  belly;  and  in 
various  organic  affections  of  the  brain  espe- 
cially, a  considerable  quantity  of  fat  is  found, 
not  only  in  the  subcutaneous  layer,  but  at  the 
outer  surface  of  the  serous  membranes. 


ADIPOSE  TISSUE. 


According  to  the  observations  of  William 
Hunter,  anasarcous  dropsy  is  the  only  disease 
in  which  the  fat  of  the  adipose  membrane  is 
entirely  consumed.  "  This  disorder,  when  in- 
veterate, has  that  effect  in  such  a  degree,  that 
we  find  the  heart  or  mesentery  in  such  subjects 
as  free  from  fat  as  in  the  youngest  children." 
This,  however,  is  in  some  degree  denied  by 
Bichat,  who  contends  that  it  is  not  uncommon 
to  find  much  subcutaneous  fat  in  subjects 
greatly  infiltrated.*  It  is  obvious  that  much 
will  depend  on  the  stage  of  the  disease.  It 
cannot  be  expected  that  the  moment  serous 
infiltration  appears  in  the  filamentous  tissue, 
all  the  fat  should  be  at  once  removed  from 
the  adipose.  The  process  of  absorption  is 
gradual  as  is  that  of  deposition ;  and  the  infe- 
rence of  Hunter  may  be  regarded  as  nearly 
exact  in  reference  to  long-continued,  or  what 
he  terms  inveterate  dropsy.  It  is  certain,  that 
while  it  is  very  difficult  to  deprive  the  bones  of 
ordinary  subjects  of  oil,  those  of  dropsical  sub- 
jects are  the  only  ones  which  it  is  possible  to 
obtain  free  from  this  substance. 

In  certain  diseases,  especially  those  the  ter- 
mination of  which  is  attended  with  serous 
effusion  into  the  cavities  of  the  serous  mem- 
brane, the  fat  is  partly  absorbed  or  may  be 
converted  into  a  sort  of  sero-gelatinous  fluid. 
In  chronic  dysentery,  for  example,  the  subcu- 
taneous fat  and  that  of  the  heart  and  omentum, 
in  a  great  measure  disappear,  while  in  their 
place  we  find  effused  an  orange-yellow  coloured 
sero-albuminous  fluid,  of  a  jelly-like  aspect, 
which  coagulates  on  the  application  of  heat  or  the 
addition  of  re-agents.  In  the  bodies  of  those, 
also,  cut  off  by  scirrhous  disorganization  or 
cancerous  ulceration,  the  greater  part  of  the 
fat  is  in  like  manner  absorbed,  and  in  its  place 
appears  a  dirty  orange-yellow  coloured  sero- 
albuminous  fluid. 

The  removal  of  the  fat  from  its  containing 
membrane  is  effected  by  the  process  of  absorp- 
tion, the  agents  of  which  are  supposed  by 
William  Hunter,  Portal,  Bichat,  and  Mascagni, 
to  be  the  lympathics.  According  to  the  results 
of  the  experiments  of  Magendie,  Mayer,  Tiede- 
mann  and  Gmelin,  Segalas  and  others,  it  must, 
in  some  measure  at  least,  be  ascribed  to  the  in- 
fluence of  minute  veins.  It  is  a  point  of  some 
interest  to  know  in  what  form  it  is  absorbed, 
whether  as  oily  matter,  or  after  undergoing  a 
process  of  decomposition  The  observation  of 
Dr.  Traill,  above  quoted,  would  lead  to  the 
former  view;  but  it  is  not  easy  to  conceive  that 
this  should  be  uniform.  We  want,  in  short, 
correct  facts  on  the  point  at  issue. 

5.  Adipose  sarcoma. — This  consists  in  an  un- 
usual deposition  of  firm  fatty  matter  in  cells, 
the  component  fibres  of  which  are  sufficiently 
firm  to  give  it  consistence.  The  tumour,  which 
is  generally  globular,  is  always  surrounded  by 
a  thin  capsule,  formed  by  the  condensation  of 
the  contiguous  filamentous  tissue.  The  tumour 
is  supplied  by  a  few  bloodvessels,  which  pro- 
ceed from  the  capsule,  but  which  form  so 
'^nder  an  attachment  that  they  are  readily 

*  Anat.  Gen.  vol.  i.  p.  57. 


broken,  and  the  tumour  is  easily  scooped  from 
its  seat.  This  sort  of  tumour  occurs  almost 
invariably  in  the  adipose  membrane,  and  seems 
to  consist  in  a  local  hypertrophy  of  the  part  in 
which  it  is  found.  It  may  have  a  broad  basis, 
but  is  often  pendulous,  or  attached  by  a  narrow 
neck  or  stalk.  It  is  the  most  common  form 
of  sarcomatous  tumour,  and  may  occur  in  any 
part  of  the  body  in  which  there  is  adipose  mem- 
brane, but  is  chiefly  found  on  the  front  and 
back  of  the  trunk,  and  not  unfrequently  on  two 
places  at  the  same  time. 

6.  Steatoma. — In  adipose  sarcoma  the  adi- 
pose  matter   is   deposited   in    cells,    and  the 
tumour  derives  a  degree  of  firmness  from  the 
fibres  with  which  it  is  thus  traversed  in  every 
direction.     In  other  instances,    however,    the 
adipose  matter  is  deposited  in  a  mass  in  the 
cavity  of  a  spherical  or  spheroidal  cyst,  formed 
in  the  filamentous  or  adipose  tissue ;  and  the 
tumour  is  soft  and  compressible,  and  seems  to 
contain  fluid  or  semifluid  matter.     When  cut 
open  it  is  found  to  contain  a  soft  semifluid 
matter  of  the  consistence  of  honey,  but  of  oily 
or  adipose  properties.     In  such  circumstances 
the  inner  surface  of  the  cyst,  or  at  least  the 
vessels  of  this  surface,  are  the  agents  which 
secrete   the  fatty  matter.     This  tumour  may 
occur  either  in  the  filamentous  or  the  adipose 
tissue,  but  is  to  be  regarded  as  an  example  of 
local  deposition  of  adipose  matter.     It  may 
appear  in  any  region  of  the  filamentous  tissue, 
but  is  most  frequent  about  that  of  the  head  and 
face.     Small  steatoms  are  not  unfrequent  in  the 
eyelids  and  in  the  scalp.     Larger  ones  are  more 
frequent  about  the  neck. 

7.  Lipoma. — This  name   was   first  applied 
by  Littre  to  a  wen  or  cyst,  filled  with   soft 
matter,  possessing  the  usual  properties  of  ani- 
mal fat.     The  matter  of  steatom,  according  to 
this  surgeon,  is  either  not  or  imperfectly  in- 
flammable,  by  reason  of  its  degeneration  or 
commixture  with  some  other  animal  secretion. 
The  propriety  of  this  distinction  has  been  de- 
nied by  Louis  and  others,  who  maintain  that 
these  tumours   differ  in  nothing,  unless   per- 
haps in  degree.     It  has  been  favoured,  never- 
theless, by  Morgagni,  and  adopted  by  Plenck, 
Desault,  Bichat,  and  various  foreign  surgeons, 
and  is  defended  by  Boyer,  who  represents  the 
steatom  as  differing  from  llpoma  in  the  matter 
being  white,  firm,  and  changed  from  its  origi- 
nal character,  and  in  possessing  the  tendency 
to  degenerate  into  cancer.     Plenck  had  previ- 
ously distinguished   the  llpoma  by  its   being 
destitute  of  a  cyst,  a  circumstance  not  required 
by  Littre. 

Though  thus  admitted  to  differ,  the  anato- 
mical character,  as  given  by  Morgagni,  and 
confirmed  by  Boyer,  is  in  both  nearly  the 
same  :  a  cyst,  containing  unchanged  fat,  or 
granular  adipose  matter,  in  cells  formed  by  the 
original  fibres  of  the  adipose  membrane,  ac- 
cording to  Morgagni,  or  those  of  the  filamen- 
tous tissue,  according  to  Boyer.  At  the  base 
or  stalk,  in  the  case  of  pendulous  steatom,  the 
cells  are  compressed,  but  loose  in  the  body  of 
the  tumour. 

This  description,  with  the  alleged  cancerous 


64 


AGE. 


tendency,  accords  more  with  the  characters  of 
the  adipose  sarcoma  than  those  of  the  genuine 
wen.  Personal  examination  enables  me  to  say, 
that,  in  the  case  of  small  steatoms  of  the  scalp, 
eyelids,  face,  &c.  no  fibres  of  this  kind  are  re- 
cognized ;  and  to  such,  if  any  distinction  be 
adopted,  the  name  of  llpoma  should  be  con- 
fined. In  the  case  of  such  larger  steatoms  as 
1  have  seen  in  other  regions  of  the  body,  though 
the  contents  are  firmly  connected  together,  and 
some  filamentous  threads  may  be  seen  here 
and  there,  or  the  tumour  may  even  be  separa- 
ble into  masses,  I  have  not  been  able  to  trace 
the  distinct  arrangement  of  cells,  mentioned  by 
Morgagni  and  Boyer.  Weidmann  mentions, 
that  in  one  case  the  matter  of  steatom  was  a 
sort  of  liquefied  fat,  and  in  another  firm  and 
dense,  and  not  divided  into  lobes  or  cells. 
The  other  forms  of  encysted  tumours,  distin- 
guished by  the  names  of  atheroma,  (a0»?£&;^a, 
pulticula,  ab  oe,^tx,^oe.,pultis  genus, )  and  mtliceris 
(pefaKrigu;,  met  and  cer«,  honey  wax,)  are  to  be 
viewed  rather  as  varieties  of  the  steatom  than 
as  generically  different.  The  substance  con- 
tained may  differ  in  consistence,  but  is  nearly 
the  same  in  essential  qualities. 

8.  Melanosis. — The  adipose  membrane  is  a 
frequent  seat  of  this  singular  deposition.  The 
black  or  melanose  matter  is  found  in  the  sub- 
cutaneous adipose  membrane,  arid  the  subja- 
cent cellular  tissue  of  the  chest  and  belly ;  it 
is  not  uncommon  in  the  fat  of  the  orbit ;  it  is 
very  commonly  seen  in  the  adipose  cushion  on 
the  forepart  of  the  vertebral  column,  on  that  sur- 
rounding the  kidneys,  and  in  the  fat  of  the  anus 
and  rectum  ;  it  is  found  in  the  anterior  and 
posterior  mediastinum  ;  and  it  is  found  be- 
tween the  folds  of  the  mesentery,  of  the  meso- 
colon,  and  of  the  omentum.  It  is  also  found 
in  the  substance  of  the  marrow  of  bones  ;  and, 
perhaps,  in  most  cases  in  which  the  osseous 
system  appears  to  be  stained  with  the  melanose 
deposite,  the  dark  matter  may  be  traced  to  the 
medullary  particles,  the  situation  of  which  it  is 
found  accurately  to  occupy. 

In  all  these  situations  it  appears  in  various 
degrees  of  perfection,  and  in  different  forms. 
It  may  be  disseminated  in  black  or  inky  spots, 
through  the  adipose  membrane ;  it  may  be  ac- 
cumulated in  spherical  or  spheroidal  masses  of 
various  size  and  shape ;  or  it  may  be  found  in 
the  form  of  brown  or  ebon-coloured  fluid  or 
semifluid,  enclosed  in  a  cyst  formed  of  the 
contiguous  tissue,  more  or  less  condensed. 

The  melanose  matter  is  entirely  destitute  of 
organization,  and  is  to  be  regarded  as  the  result 
of  a  peculiar  secretion.  No  vessels  have  been 
traced  into  it;  and  when  bodies  affected  with 
this  deposite  are  minutely  injected,  the  vessels 
can  be  traced  no  farther  than  the  enveloping 
cyst.  (Breschet.)  It  is  also  to  be  noticed  that 
it  is  never  deposited  exactly  in  the  site  of  orga- 
nic fibres,  but  always  between  them,  and  very 
generally  in  the  precise  situation  of  the  adipose 
particles.  These  several  circumstances  show 
that  the  melanose  disease  consists  not  in  a  de- 
generation or  conversion  into  another  substance, 
but  in  the  deposition  of  a  new  form  of  matter 
in  the  manner  of  a  secretion. 


In  what  form  the  melanose  substance  is  first 
deposited  we  have  few  accurate  facts  to  enable 
us  to  form  a  judgment.  Laennec  is  of  opinion 
that  it  is  first  deposited  in  a  solid  form,  and 
afterwards  becomes  fluid.  The  former  he  con- 
siders the  stage  of  crudity,  the  latter  that  of 
softening  (ramollisement.)  Several  facts,  how- 
ever, would  lead  to  the  conclusion,  that  when 
first  deposited  it  was  fluid,  and  afterwards  ac- 
quired consistence.  Thus  in  several  dissec- 
tions performed  by  Drs.  Cullen  and  Carswell,* 
the  matter  of  the  small  tumours,  which  are 
supposed  to  be  of  short  duration,  were  found 
to  be  softest,  and  sometimes  as  fluid  as  cream. 
In  like  manner,  in  a  case  recorded  by  M. 
Chomel,  in  which  the  disease  was  found  in  the 
liver  in  the  shape  of  large  cysts,  the  melanose 
matter  was  more  fluid  in  the  centre  than  in  the 
circumference  of  the  cysts.  Upon  the  whole, 
if  the  melanose  deposite  be,  as  is  supposed,  an 
inorganic  secretion,  the  idea  of  its  bring  poured 
forth  from  the  vessels  at  first  in  a  fluid  or  semi- 
fluid state  is  most  probable,  and  most  consis- 
tent with  the  usual  phenomena  and  laws  of 
animal  processes. 

BIBLIOGRAPHY. — Mnlpighi,  de  omento,  pingue- 
dine,  et  adiposis  ductibus.  Op.  Omn.  fol.  Lond. 
1686.  C.  A.  De  Berqen,  Programma  de  Mem- 
brana  Cellulosa  in  Haller  Disp.  Anat.  Select, 
torn.  iii.  Haller,  Elerae:  ta  Physiologiae,  lib.  i. 
sect.  4.  W.  Hunter,  On  Cellular  Memb.  in  Med. 
Obs.  and  Inquiries,  v.ii.  p.  26.  Bachiene,  Diss.  de 
Adipe  humano,  4to.  Ultraj.  1774.  Janssen,  Pin- 
guedinis  Animalis  consideratio.  8vo.  L.  B.  1784. 
Redhead,  Diss.  de  Adipe.  8vo.  Edinb.  1789.  Vogel, 
Diss.  sur  la  graisse.  8vo.  Paris,  1806.  Allmer, 
Diss.  In.  De  pinguedine  animali,  4to.  Jena;  1823. 
Heusinger,  System  der  Histologie.  8vo.  Gruetz- 
macher,  De  Medulla  Ossium.  (Rec.  in  Haller.  Disp, 
Anat.  vol.  vi.)  Lorry,  Sur  la  graisse  (Mem.  Soc. 
R.  de  Med.  1779.  Kuhn,  De  pinguedine.  4to.  Lips. 
1825.  Bedard,  Anatomie  Generate,  p.  156. 
Chevreul,  Rf.cherches  Chimiqties  sur  les  corps 
gras  d'origin  animale,  8vo.  Paris,  1823 ;  and  Ma- 
gendie's  Journ.  de  Phys.  torn.  iv.  Raspail,  in 
Repertoire  Gen.  d'Anat.  torn.  iii.  et  iv.  et  Nouveau 
Systeme  de  Chimie  Organique,  or  Henderson's 
Translation. 

(David  Cralgie.J 

AGE.  —  (Lat.  fctas.  Gr.  SiAma.  Germ. 
Alter.  Fr.  age.  Ital.  eta.}  This  word,  in  its 
most  extended  sense,  may  express  any  period  of 
duration.  In  reference  to  the  human  body  it 
is  used  to  denote  either  the  whole  time  occu- 
pied by  this  system  in  passing  through  its 
several  stages  from  birth  to  decay,  or,  in  a 
more  limited  signification,  that  particular  por- 
tion of  existence  commonly  designated  old 
age.  It  is  in  the  former  of  these  meanings 
that  we  employ  the  prefix  to  the  following  arti- 
cle ;  in  other  words,  we  propose  to  give  an 
account  of  the  organic  and  functional  changes 
which  the  human  system  undergoes,  from  the 
commencement  of  extra-uterine  life  to  the 
period  of  its  dissolution  by  natural  decay. 

The  term  of  human  existence  has  been  va- 
riously divided,  and  in  many  instances  with 
a  view  to  adapt  its  divisions  to  certain 
fanciful  notions  respecting  the  power  of  num- 

*  Trans.  Med.  Chir.  Soc.  Edinb.  vol.  i.  p.  264. 


AGE. 


bers;  but  the  only  rational  principle  on  which 
we  can  distinguish  certain  definite  periods, 
must  be  that  of  observing  alterations  in  the 
condition  of  the  whole  body  or  of  its  several 
organs,  and  the  correspondence  which  they 
bear  to  particular  epochs.  The  old  Aristo- 
telian division  of  human  life  into  three  stages, 
growth,  maturity,  and  decline,  is  founded  on 
this  principle ;  for,  viewing  man  as  a  whole, 
the  conditions  in  which  he  is  an  imperfect,  a 
complete,  or  a  declining  member  of  his  species, 
are  well  marked.  But  these  conditions  are 
capable  of  subdivision  according  to  the  changes 
which  particular  organs  have  undergone ;  in 
other  words,  man,  in  the  progress  of  his  pcr- 
J'ectionnement,  makes  certain  acquisitions  in  his 
structures  and  functions,  and  in  his  decline 
suffers  certain  losses  and  impairments ;  the 
more  striking  of  these  additions  to,  or  sub- 
tractions from  his  resources,  suggest  the  well- 
known  division  of  existence  into  infancy,  boy- 
hood, puberty  or  adolescence,  manhood,  old 
age,  and  decrepitude.  It  is  not  our  intention 
to  discuss  the  subject  of  age  by  describing  the 
characteristics  of  the  stages  last  enumerated ; 
we  think  it  better  to  take  a  view  of  the  general 
revolutions  which  transpire  in  the  human 
economy  during  growth,  maturity,  and  decline, 
and  under  each  of  these  heads  to  mention  the 
changes  which  particular  organs  undergo  in  the 
course  of  time,  without  limiting  ourselves  to 
distinct  stages,  the  determination  of  which  must 
be,  to  a  certain  extent,  arbitrary. 

The  consideration  of  the  alterations  which 
take  place  in  the  body  during  its  progress  from 
infancy  to  manhood  might  very  properly  be 
preceded  by  some  remarks  on  those  ultimate 
processes  which  are  essential  to  growth,  viz. — 
nutrition,  secretion  and  absorption  ;  but,  for 
information  upon  this  interesting  subject,  the 
limits  prescribed  to  this  article  compel  us  to  re- 
fer the  reader  to  that  upon  NUTRITION,  in  which 
the  processes  alluded  to  will  be  viewed  in  rela- 
tion not  only  to  the  development,  but  also  to 
the  maintenance,  and  to  the  decay  of  the 
tissues. 

On  comparing  a  young  with  an  adult  animal 
we  are  at  first  struck  by  the  difference  in  bulk  ; 
but  immediately  afterwards  our  attention  is 
attracted  by  the  difference  in  their  respective 
capabilities  of  action, — a  difference  not  merely 
proportionate  to  that  of  size.  A  closer  ex- 
amination informs  us,  that  in  the  infant  many  of 
the  parts  of  the  body  are  absolutely  incomplete, 
as  organs  or  instruments,  and  we  proceed  to  in- 
vestigate whether  this  imperfection  holds  with 
all  the  organs  or  only  with  some  of  them;  and 
if  the  latter  be  the  case,  whether  the  parts  thus 
existing  only  in  a  rudimentary  state  belong  to 
a  particular  class.  Now,  the  organs  and  func- 
tions of  man,  in  common  with  those  of  other 
animals,  are  divided  into  those  which  he  shares 
with  organic  beings  in  general,  and  those 
which  distinguish  him  as  an  animal ;  the  former 
subserving  his  own  independent  existence,  the 
latter  his  existence  in  relation  to  external  ob- 
jects of  his  consciousness  ;  these  more  or  less 
subjected  to  the  control  of  volition,  those  re- 
moved, under  ordinary  circumstances,  from  the 

VOL.   I. 


government  of  this  principle.  Hence  these  tvro 
classes  have  been  variously  named  organic 
and  animal,  nutritive  and  relative,  automatic 
and  voluntary  ;  and,  as  life  is  a  term  employed 
to  designate  the  collective  functions  according- 
to  some  physiologists,  or  the  cause  of  them  ac- 
cording to  others,  we  have  organic  life  and 
animal  life,  &c.,  &c.  But  the  animal  functions 
are  truly  supplemental ;  they  could  not  subsist 
but  by  virtue  of  the  organic ;  while,  on  the 
other  hand,  the  latter  are  perfectly  capable  of 
a  separate  existence,  as  in  the  vegetable  world, 
or  in  those  conditions  of  animal  life  in  which 
its  characteristics  are  all  but  suspended,  such 
as  profound  sleep  and  apoplexy.  Yet,  al- 
though the  functions  of  relation  are  thus  de- 
pendent on  those  of  nutrition,  it  is  evident,  at  a 
moment's  glance,  that  the  latter  viewed  col- 
lectively in  an  animal  structure,  would  present 
an  aspect  altogether  incomplete,  and  different 
from  that  which  we  notice  in  the  system  of  a 
vegetable.  In  the  one  case  they  were  obviously 
intended  to  act  only  for  themselves  and  for  one 
another ;  in  the  other  they  have  an  ulterior 
object  to  fulfil,  but  for  which  they  would 
not  have  been  called  into  existence  and  opera- 
tion; this  object  is  the  production  and  support 
of  the  functions  that  constitute  the  animal. 
If  we  now  look  at  the  new-born  infant  in  con- 
trast with  the  full-grown  man,  we  at  once  per- 
ceive that  the  essential  difference  between  them 
has  reference  to  the  life  of  relations ;  in  other 
words,  the  immaturity  of  the  former  is  not  de- 
termined by  the  state  of  the  vegetative  organs, 
which,  as  organs,  are  perfect,  but  by  the  unde- 
veloped conditions  of  the  parts  which  are  to 
receive  impressions  from,  and  to  re-act  upon 
surrounding  objects.  Thus,  on  the  one  hand, 
we  observe  that  the  food  adapted  to  the  little 
being  is  rapidly  converted  into  chyle,  that 
the  blood,  after  undergoing  its  requisite  changes, 
performs  its  circuit  freely  and  effectively,  and 
that  the  activity  of  the  nutritive,  secernent,  and 
absorbent  processes  is  evidenced  by  the  quick 
increase  of  growth,  and  by  the  abundant  fluids 
contained  in  the  various  tissues.  But,  on 
turning  to  the  relative  functions,  we  find  the 
case  altogether  reversed  ;  sensation  is  dull,  faint, 
and  flitting;  voluntary  motion  scarcely  ex- 
ceeds the  amount  necessary  for  obtaining  nutri- 
ment from  the  parent ;  while  the  demonstra- 
tions of  intelligence  are  the  very  lowest  com- 
patible with  our  belief  in  the  possession  of 
such  a  principle  by  the  being  in  question.  An 
examination  of  the  organs  devoted  to  these 
several  actions  leads  to  results  in  accordance 
with  what  we  observe  in  the  functions  them- 
selves; in  the  one  class  the  organization  is 
complete,  in  the  other  much  remains  to  be 
accomplished.  If  the  apparatus  of  digestion 
be  inspected,  the  parts  employed  in  deglutition, 
viz.,  the  tongue,  pharynx,  and  oasophagus,  will 
be  found  fully  formed  ;  in  the  stomach  the 
parts  required  for  accommodating  the  aliment 
during  its  stay  and  for  mixing  certain  fluids 
with  it,  are  properly  developed;  no  deficiency 
is  observable  in  the  structure  of  the  liver 
and  pancreas ;  and  the  chyliferous  vessels  are 
pervious,  extensile,  and  perhaps  contractile.  If 


AGE. 


we  proceed  to  the  organs  of  circulation,  similar 
conditions  are  observable.  In  the  heart  the  seve- 
ral cavities,  valves,  and  fibrous  arrangements  are 
duly  proportionate  to  each  other,  and  possess  such 
qualities  of  firmness,  pliancy,  extensibility  and 
contractility  as  are  required  for  receiving,  expel- 
ling, agitating,  and  keeping  in  separate  compart- 
ments the  two  different  kinds  of  blood  ;  the 
arteries  are  found  resistent  enough  to  hold  the 
blood  within  their  calibres,  and  at  the  same 
time  elastic  enough  to  adapt  themselves  to  the 
varying  quantity  of  their  contents,  while  the 
veins  are  found  so  organized  both  as  to  the 
muscularity  of  their  coats,  and  to  the  perfection 
of  their  valves,  as  to  be  quite  capable  of  con- 
veying the  fluid  back  to  the  heart.  Not  less 
complete  is  the  apparatus  of  respiration, 
whether  we  regard  the  development  of  the 
diaphragm,  or  the  elasticity  of  the  thorax,  or 
the  cellular  and  tubular  arrangements  in  the 
lungs  and  their  appendages.  For  affording  the 
necessary  conditions  for  the  occurrence  of  those 
molecular  motions  which  constitute  deposition 
and  absorption,  and  upon  which  secretion  also 
depends,  we  find  an  infinite  number  of  capillary 
tubes  well  formed  for  supplying  the  fluids  from 
which  new  particles  may  be  taken,  and  to  which 
old  ones  may  return,  and  so  disposed  as  not  to 
interfere  with  the  action  of  any  supposable 
chemical  affinities.  If  we  next  direct  our  at- 
tention to  the  organs  of  the  animal  functions, 
an  opposite  set  of  facts  will  directly  meet  us. 
In  the  locomotive  system,  the  bones  are  dis- 
covered imperfectly  ossified,  the  muscles  de- 
ficient in  fibrin,  and  the  tendons  and  ligaments 
in  firmness  and  density.  Of  the  organs  of 
sensation  it  may  be  said,  in  general  terms,  that 
the  mechanism  employed  in  the  application 
of  the  appropriate  stimulus  is,  for  the  most  part, 
incomplete,  while  a  difference  is  also  observa- 
ble in  certain  properties  of  the  nervous  sub- 
stance. 

From  this  view  it  might  at  first  be  con- 
cluded that,  in  order  to  trace  the  changes  that 
ensue  between  the  commencement  of  extra- 
uterine  life  and  the  attainment  of  maturity,  we 
have  only  to  look  for  them  in  the  organs  of 
the  relative  life.  But  the  survey  that  we  are 
about  to  take  of  the  changes  in  question  will 
show  that  the  other  class  of  organs  are  by  no 
means  exempt  from  alteration,  although  the 
changes  are  not  those  of  development.  They 
will  be  found  to  have  reference  to  degree  or 
amount  of  function  rather  than  to  capacity. 

The  external  characters  of  the  infant  just 
eliminated  from  the  uterus  at  the  full  period  of 
gestation  are  as  follows: — the  integuments 
are  thin,  tender,  and  covered  with  a  white 
unctuous  matter ;  the  nails  just  reach  the  ends 
of  the  fingers  ;  the  trunk  and  limbs  are  round 
and  plump;  and  the  articulations  are  in  a 
state  of  flexion.  The  average  weight  of  the 
body  is  about  six  or  seven  pounds ;  the  length 
varies  from  seventeen  to  twenty-one  inches, 
sometimes  falling  short  of  or  exceeding  these 
limits.  The  point  which  lies  midway  between 
the  two  extremities  is  at  the  umbilicus.  The 
dimensions  of  the  head  and  of  the  abdomen 
are  very  large  in  proportion  to  the  other  cavities, 


and  as  compared  with  their  own  measurements  in 
after  periods  of  life.  The  pelvis  looks  con- 
tracted, the  thorax  flattened  at  its  sides  and 
prominent  in  front,  and  the  lower  extremities 
are  less  developed  than  the  upper.  A  line 
drawn  from  the  occiput  to  the  chin  measures 
five  inches  and  three  lines ;  from  the  occiput 
to  the  forehead  four  inches  and  three  lines ; 
and  from  the  vertex  to  the  base  of  the  skull 
three  inches  and  six  lines.  The  circumference 
of  the  head,  taken  along  the  course  of  the 
median  line,  is  from  thirteen  to  fourteen  inches ; 
but  taken  horizontally,  and  passing  over  the 
parietal  protuberances,  it  seldom  measures 
more  than  ten  or  eleven  inches.  The  contrast 
between  this  general  aspect  and  that  of  a  full- 
grown  man  is  too  obvious  to  require  any  repre- 
sentation of  it  here. 

The  characters  of  the  interior  will  be  best 
described  and  understood  by  examining  ana- 
lytically the  several  apparatuses  of  the  func- 
tions. Of  the  latter  the  most  simple  and 
primitive  is  assimilation,  consisting  of  certain 
molecular  motions  which  maintain,  repair,  and 
mould  the  organic  tissues.  We  have  already 
observed  that  the  requisites  for  this  function 
are  perfect  in  the  new-born  infant;  a  copious 
supply  of  the  fluid  from  which  the  textural 
particles  are  to  be  elaborated,  a  ready  ingress 
for  this  fluid,  and  a  no  less  ready  egress  for 
that  which  receives  the  particles  no  longer 
required  in  the  process.  All  that  we  know 
of  the  mechanism  employed  is  a  porous  ex- 
tensile substance,  varying  in  its  chemical  con- 
stitution according  to  the  nature  of  the  tissue. 
Porosity  is  resolvable  into  a  collection  of 
infinitely  minute  tubes,  and  the  degree  of 
porosity  is,  therefore,  determined  by  the 
number  of  the  tubes ;  the  extensibility  depends 
on  the  composition  of  the  tubes.  The  tissues 
of  the  infant  are  soft,  they  abound  in  fluids, 
and  are  more  capable  of  imbibition  or  artificial 
injection  than  at  later  periods  of  life ;  this 
being  consequently  possesses  a  complete  me- 
chanism of  nutrition.  But  this  mechanism 
can  be  of  little  utility  unless  the  nutrient 
fluid  be  supplied  liberally,  and  after  furnish- 
ing the  atoms  for  the  formation  of  the  several 
textures  give  place  to  fresh  supplies.  These 
conditions  are  afforded  by  the  arteries  and 
veins. 

There  is  no  period  of  human  existence  in 
which  the  processes  of  interstitial  growth  are 
so  active  as  in  infancy,  whether  they  be 
instanced  in  the  accretion  of  matter,  in  the 
change  of  composition,  or  in  the  modification 
of  form.  This  fact  is  in  harmony  with  the 
state  of  the  capillary  system  just  described, 
and  it  will  be  found  to  correspond  no  less 
with  the  relative  construction  of  the  arteries 
and  veins.  The  function  of  the  former  of 
these  is  to  convey  the  blood  into  the  tissue, 
of  the  latter  to  take  it  away ;  consequently 
in  a  part  where  the  growth  is  most  energetic, 
we  might,  a  priori,  expect  that  the  former 
would  be  more  numerous,  capacious,  and 
distensible.  This  is  well  known  to  be  the 
case  from  actual  observation,  partly  of  the 
effects  of  artificial  injection,  and  partly  of 


AGE. 


the  phenomena  of  disease.     An  examination     commences,    and   rapidly  proceeds  until  the 
of  the  textural  properties  of   the  two  sets  of     thickness  of  the  latter  is  to  that  of  the  former 
vessels   leads   to   the   same    conclusion.      Sir     as   1:4.     This  change  corresponds  with  the 
Chfton   Wintringham,    in    his    Experimental     closure  of  the  foramen  ovale,  tin-  <>l»lit< ration 
Enquiry,  fully  demonstrated  that  the  venous     of  the  ductus  arteriosus,  and  the  consequ.  nt 
coats   in   the   young   animal    far    exceed   the     execution  of  the  systemic  circulation   by  the 
arterial   in   density,    and   that,    consequently,     left  ventricle  only.     The  relative  capacitV 
they   are  less   subject  to   distension.      When     the  right  and  left  cavities  begin  to 
maturity  is  attained,  the  disproportion  between     after  birth.     From  tables  given  by   M< •«•: 

longer  appears  that,  while  at  birth  the  capacity  of  the 
former  compared  with  that  of  the  latter  is  as 
1  :  1$,  at  the  age  of  50  it  is  nearly  3:1.* 

The  lungs  at  the  moment  of  birth  undergo 

vessels,  these  can  be  of  no  avail  unless  the  a  more  remarkable  alteration  in  their  form, 
fluid  they  contain  possesses  certain  chemical  their  texture,  and  their  contents,  than  any 
properties.  Now  the  blood  in  early  extra-  other  organ  in  the  system ;  but  during  infancy 
uterine  life  presents  the  same  general  characters  and  childhood  they  present  no  appreciable 
as  in  more  advanced  periods ;  but  there  is  yet  change  in  their  organization,  although  a  change 


no 


the    resistances   of  these   vessels 
exists. 

However  well  provided  the  infant  may  be 
with  the  mechanical  apparatus  of  pores  and 


wanting  a  comparative  analysis  of  this  fluid 
at  different  ages.*  Inferentially  we  can  enter- 
tain no  doubt  that  it  is  fully  adapted  to  the 
purposes  of  nutrition,  when  we  consider  the 
conditions  of  the  chylifactive  and  respiratory 
functions,  and  that,  although  the  differences 
of  its  composition  in  early  and  in  more  mature 


must  be  inferred  from  the  increase  of  their 
function.  In  infancy  there  is  a  smaller  con- 
sumption of  oxygen ;  and  the  power  of  gene- 
rating heat,  a  function  so  intimately  connected 
with  respiration,  is  inferior  to  that  possessed 
in  later  periods.  Much  light  has  been  thrown 
on  this  subject  by  the  researches  of  Dr.  Ed- 


periods  have  not  been  denned  by  experiment,     wards;  and  practical  observations  of  the  highest 


they  must  bear  a  relation  to  the  different  de- 
grees of  nutrition  and  secretion.  The  differ- 
ence, however,  between  the  blood  of  the  infant 
and  that  of  the  aged  is  perceptible  to  the 
senses,  and  will  be  noticed  hereafter. 

Pursuing  the  channels  of  the  blood  to  the 
heart,   we   find   this   organ,    as   stated  above, 


mportance  in  the  management  of  infants, 
founded  upon  the  facts  which  he  has  ascer- 
tained, are  to  be  met  with  in  his  valuable 
work.f  The  inspirations  and  expirations  are 
more  frequent  at  this  early  period,  although 
the  chemical  actions  between  the  air  and  the 
blood  are  less  considerable.  This  greater  fre- 


complete  in  its  functions.     Its  volume,  how-  quency  is  a  necessary  accommodation  to  the 

ever,  is  large  in  proportion  to  the  size  of  the  rapidity  of  the  circulation.    At  puberty  there 

body.      Its  parietes  are   less  firm  in  texture,  is  a  marked  development  of   the  organs  of 

and   of    a  paler  colour  than  they  afterwards  respiration ;  the  volume  of  the  lungs  increases 

become  ;  but  their  contractility  is  more  active,  in  conformity  with  the  expansion  of  the  thorax; 


The    pulsations  are   from    120   to    140  in  a 
minute.      The   large  volume   is   in  harmony 


while  the  greater  determination  of  the  blood 
to  their  vessels  is  indicated  by  the  deeper  hue 


with  the  quantity  of  the  fluid,  the  comparative  of  the  parenchyma,  by  the  liability  to  pulmo- 
weakness  of  its  parietes  with  the  small  extent  to  nary  hemorrhage,  so  characteristic  of  this 
which  their  impulse  requires  to  be  propagated,  period,  and  perhaps  also  by  certain  diseases 
and  with  the  trifling  resistance ;  and  the  quick  which  affect  the  nutrition  of  these  organs. 
successions  of  its  contractions  furnish  the  fresh  The  corresponding  activity  of  function  is  null- 
supplies  of  the  nutriment  required  by  the  cated  by  the  increased  power  of  calorification, 
energy  of  growth.  In  the  progressive  develop-  the  energy  of  muscular  motion,  and  the  exalta- 


ment  of  this  organ  we  notice  that  the  bulk, 
although  increasing  so  long  as  general  growth 
continues,  is  proportionately  smaller,  a  cir- 
cumstance that  corresponds  with  the  diminution 


tion  of  the  cerebral  actions;  functions  well 
known  to  have  a  direct  relation  with  that  of 
respiration  ;  while  the  establishment  of  the 
generative  faculty  appears  to  own  a  connexion, 


of   the   circulating   fluid ;    the  fibres  become     though  somewhat  more  remote,  with  the  pul- 


stronger  and   of  a   deeper  hue,    so   that  the 
contractions  are  more  capable  of   propelling 


monary  development. 

We  pass  from  the  system  which  imparts 


v^wii  1. 1  a,VsiiwLio     cue     niv/ic*     Vsu.ijci.uii'     \Ji       |*«v|/v*au«£  v     j; »  .  ,  -.    .    , 

the  blood  through  the  greater  extent  which  it  new  properties  to  the  blood   to    tn; 

has  now  to  traverse,  or,  more  strictly  speaking,  supplies  it  with  nutriment.     No  imper 

of  communicating  a  shock  to  a  greater  column;  is  discoverable  in  the  apparatus  < 

but  the  pulsations  are  slower,  agreeably  to  the  in  the  new-born  infant ;  every  01 

diminished  requirements  on  the   part  of  the  plete   as  an   organ     but    passes   throi 

capillary  actions.     We  must  not  omit  to  ob-  rious  changes  in  adaptation  on  the  . 

serve   that   at   birth  the   parietes   of  the   left  to  the  food  that  is  supplied,  and  to  the  mode 


ventricle  scarcely  exceed  those  of  the  right  in     of  receiving  it,  and  on  the  other  hand  tn  the 
thickness;  but  from  this  period  an  alteration     demands  of  the  other  parts  of  the  t  ody.     Ih 

organs  employed  in  conveying  and  modifying 

*    De  Blainville  states,    on    the    authority    of     the  chyle,  viz.  the  lacteals  and  the  mesent 
Fourcroy,  that  in  infancy  the  albumen  of  the  blood 
is    more   abundant,    that   the  fibrin  is  softer    and 


more   gelatinous,    and   that  the  phosphates  are  in 

--J-    Cours 


de  Physiologic,  t.  ii.  p.  262. 


*  Manuel  d  A  aat.  t. 


translated  by 


p.  284. 


&c. 


AGE. 


glands,  are  in  a  state  of  high  development, 
as  indicated  both  by  their  size  and  by  their 
tendency  to  disease.  The  stomach  and  duo- 
denum are  fully  formed,  but  the  sensibility 
of  their  mucous  membrane  is  adapted  only  to 
the  milk  of  the  mother;  any  other  kind  of 
food  has  a  greater  or  less  tendency  to  produce 
irritation.  This  membrane  is  thick,  extremely 
villous  and  vascular,  and  consequently  of  a 
rose-colour.*  In  young  persons  it  assumes 
a  milky  or  satin-like  appearance;  in  the  adult 
it  becomes  slightly  ash-coloured,  especially  in 
the  duodenum  and  in  the  commencement  of 
the  ileum  ;  in  the  old  subject  it  is  more  de- 
cidedly ashy.  Its  whitish  appearance,  according 
to  Andral,f  is  found  either  in  very  old  persons 
or  in  younger  subjects  who  have  died  of  ma- 
rasmus. In  the  adult  the  small  intestines, 
according  to  Orfila,J  bear  a  proportion  of  eight 
to  one  as  compared  with  the  distance  from  the 
mouth  to  the  anus ;  in  the  infant  the  propor- 
tion is  no  less  than  twelve  to  one.§  The  large 
intestines  are  longer  with  respect  to  the  small 
intestines  in  the  infant  than  in  the  adult;  but  their 
calibre  is  proportionally  smaller.  Ascending  to 
the  mouth  we  might  be  tempted  to  say  that 
there  is  evidence  of  incompleteness  in  the  ab- 
sence of  teeth;  but  a  moment's  consideration 
assures  us  that  the  organs  collected  in  this  part 
are  all  eminently  adapted  to  their  function. 
The  food  is  already  prepared  by  the  mother, 
and  only  needs  to  be  extracted  and  conveyed 
into  the  pharynx ;  actions  which  are  perfectly 
achieved  by  the  lips,  cheeks,  and  tongue. 
When  the  period  has  arrived  at  which  this 
food  can  no  longer  be  furnished  with  safety 
to  the  mother,  and  when  all  the  purposes  are 
accomplished  which  were  intended  in  this 
close  connexion  between  the  two  beings — 
purposes  in  all  probability  of  a  moral  as  well 
as  a  physical  character — the  infant  is  prepared 
for  a  more  independent  existence  by  the  emer- 
gence of  teeth.  This  event  generally  begins 
about  the  sixth  or  seventh  month  by  the  appear- 
ance of  the  two  middle  incisors  in  the  lower 
jaw ;  these  are  followed  by  the  corresponding 
teeth  in  the  upper  jaw;  next  are  seen  the 
lateral  incisors  below  and  above :  the  rest 
appear  in  the  following  order ; — the  first  molars, 
the  canines,  and  the  second  molars ;  those  of 
the  lower  jaw  having  generally  the  priority 
of  emergence.  The  milk-teeth,  as  they  are 
called,  by  the  end  of  the  seventh  year  have 
given  way  to  the  second  and  permanent  series. 
For  the  different  characters  of  the  two  sets, 
the  order  of  their  appearance,  and  other  par- 
ticulars, we  beg  to  refer  the  reader  to  the 
article  TEETH.  That  the  first  series  should 
be  only  temporary  is  a  necessary  provision, 
in  conformity  with  the  change  in  the  conforma- 
tion of  the  maxillary  bones  which  ensues  at 
the  same  time. 

We  must  not  leave  the  alimentary  tract  with- 

*  Billard,  Traite  des  Maladies  des  Enfans,  &c. 

t  Precis  d'Anat.  Pathol. 
i    }  Lemons  de  Med.  Leg.  t.  i.  p.  62. 

§  This  statement  is  at  variance  with  that,  of 
Meckelj,  who  says  that  the  small  intestine  is  much 
shorter  in  the  early  periods.  Op.  cit.  t.  iii.  p.  424. 


out  observing  that  the  fibres  of  the  stomach 
and  intestines  in  infancy  and  childhood  are, 
like  those  of  the  heart  and  other  involuntary 
muscles,  more  irritable  than  in  after  life ;  hence 
the  contents  of  these  viscera  are  propelled  more 
rapidly,  and  the  evacuations  are  more  frequent; 
their  tissue  is  also  softer,  and  their  colour  more 


approaching:  to  white. 
The  liver 


undergoes  a  great  change  after 
birth  both  in  form  and  in  function.  The  pecu- 
liar circulation  of  which  it  formed  so  important 
an  organ  during  foetal  life  being  abolished, 
the  left  lobe  which  nearly  equalled  the  right 
in  volume,  is  diminished  to  a  third  of  its  original 
size.  But  while  the  umbilical  vein  and  the 
canalis  veriosus  are  obliterated,  the  vena  portse 
is  developed,  and  the  bilious  secretion  becomes 
the  predominant  function.  Of  the  further 
changes  which  this  organ  experiences,  we  have 
very  little  knowledge,  except  that  the  whole 
bulk  is  greatly  lessened,  and  that  the  colour  of 
its  parenchyma  becomes  darker,  and  that  it  is 
more  subject  to  disease  in  after  periods.  Oc- 
casionally we  meet  with  instances  in  which  the 
foetal  proportions  of  the  liver  continue  through 
life  (Andral).  The  bile  has  not  been  carefully 
examined  with  reference  to  particular  ages, 
but  it  is  known  to  be  less  viscid  and  to  contain 
a  smaller  quantity  of  its  peculiar  principles 
in  infancy ;  while  its  greater  liability  to  con- 
cretions at  more  advanced  periods  indicates  an 
alteration  in  its  composition.  The  gall-blad- 
der, though  small  at  birth,  contains  bile,  green 
in  colour  and  bitter  in  taste,  and  soon  becomes 
enlarged. 

The  spleen  also  increases  in  volume,  but 
what  alteration  takes  place  in  the '  progress 
to  maturity,  in  its  function,  must,  of  course,  be 
doubtful  until  the  function  itself  be  better 
understood.  Probably  its  enlargement  is  con- 
nected with  the  distended  condition  of  the 
venous  system.  Of  the  changes  in  the  pan- 
creas and  salivary  glands,  we  know  little  more 
than  that  their  texture  increases  in  firmness. 
The  lacteals,  lymphatics,  and  their  respective 
ganglions  have  a  very  marked  development. 
It  is  to  be  regretted  that  no  observations  have 
as  yet  been  made  upon  the  composition  of  the 
chyle  at  different  ages.  There  are  doubtless 
many  alterations  corresponding  to  the  varying 
activity  of  the  digestive  function,  and  to  the 
kinds  of  aliment  used  at  those  periods. 

So  much  for  the  organs  and  functions  which 
are  concerned  in  augmenting  or  modifying  the 
nutrient  matter.  Before  proceeding  to  those 
of  the  relative  life,  we  must  allude  to  the 
organs  of  excretion.  The  kidneys  at  birth 
have  not  lost  the  traces  of  their  lobular  forma- 
tion, but  these  are  soon  effaced.  The  weight 
of  these  organs  at  birth  is  to  that  of  the  whole 
body  as  1-80;  in  the  adult  1-240.  The  me- 
dullary portion  is  more  abundant  than  the  corti- 
cal in  early  life.  The  supra-renal  capsules  soon  be- 
gin to  shrink  from  their  foetal  size.  The  ureters 
are  large,  and  the  bladder  has  a  more  elongated 
form  than  in  after  periods ;  it  also  occupies  a 
higher  situation  above  the  pelvis.  The  func- 
tional qualities  of  these  forms  are  not  so  well 
ascertained  as  the  analogy  of  their  organization  to 


AGK. 

that  of  inferior  animals.  The  urine  is  retained 
a  shorter  time  in  the  bladder ;  it  is  more  aqueous 
and  less  impregnated  with  saline  and  animal 
ingredients  than  in  after  life;  there  is  also  a 
particular  deficiency  of  urea.  Of  the  intes- 
tines we  have  already  spoken  ;  their  contents 
are  copious  but  less  feculent  than  they  after- 
wards become.  The  perspiration  affords  a  si- 
milar character  to  that  of  the  other  excrernenti- 
tious  secretions,  being  more  aqueous,  less  sa- 
line, and  less  odorous.  On  the  whole  it  may 
be  said  that  less  activity  is  indicated  in  the 
egestive  than  in  the  ingestive  system. 

Of  the  defensive  organs,  or  those  which 
are  exposed  to  surrounding  agents,  we  may 
remark,  in  general  terms,  that  although  fully 
adequate  to  the  demands  of  the  infant  under 
the  circumstances  of  his  existence,  they  acquire 
a  development  proportionate  to  his  growing  in- 
dependence of  the  care  of  others.  The  skin 
increases  in  firmness,  and  the  epidermis  in  thick- 
ness ;  the  sebaceous  follicles  become  larger  and 
more  numerous,  and  the  hair  is  more  abundant. 

There  is  a  portion  of  the  nervous  system 
which  we  have  every  reason  to  consider  more 
related  with  the  functions  which  have  been  just 
reviewed,  than  with  those  of  the  animal  life,  and 
which  might  a  priori  be  expected  to  bear 
a  corresponding  ratio  of  developement.  We 
allude  to  the  ganglions;  they  appear  to  be 
fully  formed  at  birth,  but  what  changes  they 
undergo  between  that  period  and  maturity  we 
do  not  profess  to  know.  In  old  age  their 
tissue  is  found  hardened,  shrunken,  and  of  a 
greyish  colour.  (Bichat.) 

The  changes  that  we  have  next  to  take 
notice  of  are  of  a  totally  different  character 
from  the  foregoing.  They  consist  not  merely 
in  augmentations  of  size,  correspondently  with 
the  general  increment  of  the  body,  or  in  modi- 
fications of  organs  according  to  the  altered 
circumstances  under  which  they  have  to  act, 
but  in  processes  essential  to  the  completeness 
of  certain  organs.  These  are  the  parts  em- 
ployed in  locomotion,  voice,  sensation,  and 
thought.  We  shall  begin  with  the  osseous 
system. 

Bones  are  not  subservient  to  locomotion 
only ;  they  have,  in  some  parts  of  the  body, 
the  important  office  of  enclosing  and  defending 
'from  external  injury  the  more  delicate  organs  of 
the  system.  We  shall  find,  therefore,  that  in 
the  young  animal,  according  as  they  fulfil  the 
one  office  or  the  other,  their  development  will 
differ.  But  whatever  be  the  functions  of  the 
bones,  they  require,  for  the  perfection  of  that 
function,  three  mechanical  properties, — firm- 
ness, lightness,  and  tenacity.  They  must  not 
admit  of  flexion,  and,  at  the  same  time,  the 
density  of  their  substance  must  not  render 
them  cumbrous  by  weight,  or  brittle  in  texture. 
To  present  these  three  conditions,  the  organs  in 
question  consist  of  two  principal  ingredients, 
an  animal  matter  and  an  earthy  matter,  most 
intimately  interwoven  ;  the  one  preventing  such 
vibrations  as  would  occasion  risks  of  fracture, 
the  other  affording  the  necessary  strength  in 
supporting  weights, and  in  resisting  the  divellent 
tendencies  of  antagonist  muscles.  The  pro- 


portion which  these  parts  bear  to  e  ,d,  ,nh«- 
vanes  with  .  the  tgea  of  the  hum;,,,  subject! 
Viewed  as  u  part  of  the  system  cl«  v,,u  ,1  ,.',  ,1  ,.' 
lite  of  relations,  bones  aiv  used  u  ,, 
support,  as  levers  in  various  attitudes  and  mo- 
tions, and  as  />,»///>  r/V//,/>///  to  the  mus,  k 
tendons.  On  examining  the  constitution  of 
these  portions  of  the  osseous  syM.-m  in  the 
new-born  infant,  we  find  the  quantity  of  <al- 
careous  salts  comparatively  small,  and  even 
the  animal  substance  softer  than  in  later  pe- 
riods, in  consequence  of  the  greater  ratio  of 
gelatine.  In  growth  these  proportions  undergo 
a  gradual  altemtion  ;  the  gelatine  is  dimu, 
the  cartilage  becomes  firmer,  and  both  give 
way  to  the  deposition  of  earthy  particles :  in 
the  increase  of  density  produced  by  this  de- 
position consists  the  process  of  ossification. 
To  particularize  the  incompleteness  of  tin- 
osseous  system  would  require  us  to  enter  upon 
the  anatomy  of  almost  every  bone  in  the  body, 
an  investigation  incompatible  with  the  limits  of 
this  article.  Some  idea  of  it  may  be  obtained 
from  the  fact  that  all  the  epiphyses  of  the  long 
bones,  and  the  greater  number  of  the  apophyses 
are  as  yet  but  cartilaginous;  they  derive  their 
ossification,  not  from  an  extension  of  the  pro- 
cess in  the  bones  to  which  they  are  attached, 
but  from  ossific  centres  within  their  own 
spheres.  In  the  tarsus  the  only  bones  in 
which  ossification  has  commenced  are  the  as- 
tragalus and  os  calcis.  The  carpus  is  entirely 
cartilaginous.  The  os  innominatum  of  the  pel- 
vis consists  of  three  separate  bones ;  ossifica- 
tion has  but  just  commenced  in  the  descending 
ramus  of  the  pubis,  and  the  ascending  part  of 
the  ischium  ;  and  the  consolidation  of  the  pel- 
vis is  not  complete  till  after  the  thirteenth  year. 
The  long  bones  have  no  central  medullary 
cavity  in  the  early  periods  of  intra-uterine  life ; 
but  in  the  fcetus  at  its  full  term,  the  animal 
matter  which  occupied  that  space  has  begun  to 
be  absorbed,  and  the  deposition  of  osseous 
matter  takes  place  in  the  form  of  a  cylindrical 
sheath,  so  that  the  canal  exists  at  this  period, 
though  in  an  incomplete  state.  The  medullary 
canal  is  analogous  to  the  cells  of  the  short  and 
flat  bones,  and  of  the  extremities  of  the  long 
bones,  which  are  also  incomplete  in  infancy. 
The  shape  of  the  cylindrical  bones  is  mani- 
festly different  from  that  which  they  afterwards 
assume ;  thus  there  is  a  much  smaller  dispro- 
portion between  the  diameters  of  the  extremi- 
ties and  that  of  the  shaft ;  the  surface  is  less 
furrowed  by  sinuses  or  roughened  by  ridges; 
differences  exactly  corresponding  to  the  imper- 
fect development  of  the  muscles,  which,  when 
more  bulky  in  their  middle  portions,  require  a 
larger  space  for  their  accommodation  about 
the  body  of  the  bone,  and  when  stronger  in 
contraction,  require  attachments  that  will 
them  in  firmness.  The  osseous  system  is  not 
complete  till  after  the  age  of  twenty. 

There  is  no  part  of  the  skeleton  in  which  we 
have  a  more  striking  illustration  of  its  gradual 
development  than  in  the  bones  of  the  face  and  in 
the  cranium.  It  is  not  till  the  seventh  year  that 
a  separation  begins  to  take  place  between  the 
tables  of  the  skull,  that  the  frontal  sinus  begins 


70 


AGE. 


to  open,  that  the  nasal  bones  lengthen,  that  the 
cells  of  the  malar  and  upper  maxillary  bones 
are  enlarged,  that  in  consequence  of  this  ex- 
pansion of  their  cavities  the  outer  lamina  pro- 
jects, and  that  the  lower  jaw  is  elongated. 
The  stationary  condition  of  the  tabula  vitrea 
is  conformable  to  the  arrest  in  the  increment  of 
the  brain ;  the  extension  of  the  outer  table  to 
the  increasing  power  and  action  of  the  muscles 
attached  to  it ;  the  development  of  the  sinuses 
and  cells  to  that  of  the  voice  and  certain  of  the 
senses ;  and  the  projection  of  the  jaws  to  the 
increased  number  of  the  teeth.  But  although 
these  changes  commence  as  early  as  the  seventh 
year,  they  are  not  complete  till  the  twenty-first, 
or  even  later.  At  this  time  the  countenance 
becomes  settled,  not  merely  by  the  full  deve- 
lopment of  the  muscles,  which  express  the 
predominant  emotions  of  the  individual,  but 
also  by  the  complete  adjustment  of  the  bony 
arrangements  j ust  enumerated. 

Those  portions  of  the  osseous  system  which 
are  employed  in  protecting  the  organs  enclosed 
by  them  from  external  compression  or  injury, 
have  attained  a  degree  of  growth  far  surpass- 
ing that  of  the  bones  devoted  to  locomotion 
and  to  the  mechanism  of  sensation.  The  ribs,  for 
instance,  defending  the  lungs  and  the  heart, 
and  playing  so  important  a  part  in  respiration, 
are  farther  advanced  in  the  ossific  process  than 
the  bones  of  the  extremities.  But  the  most 
striking  fact  of  this  kind  is  presented  in  the 
spinal  column.  The  annular  portions  of  the 
vertebrae  which  form  the  canal  of  the  medulla 
spinalis,  are  found  strongly  ossified  at  birth, 
but  the  bodies  of  these  bones,  which  are  to  be 
used  hereafter  in  supporting  the  weight  of  the 
head  and  trunk,  are  very  slightly  expanded, 
and  all  but  devoid  of  earthy  particles,  while 
the  processes  to  which  the  muscles  employed 
in  the  flexion  and  extension  of  the  column  after- 
wards contract  attachments,  are  either  only 
shaped  in  cartilage,  or  may  be  said  to  have  no 
existence. 

Passing  from  the  bones  to  the  muscles,  we 
observe  the  latter  no  less  incomplete  in  infancy 
as  it  regards  their  physical  characters ;  they  are 
pale,  flabby,  and  easily  torn  ;  they  contain  less 
fibrine  than  in  after  years;  their  contractility  is 
weak  though  easily  excited ;  and  the  fasciculi 
and  fibres  are  but  loosely  connected  from  the 
want  of  the  fasciae  and  aponeuroses  which  brace 
them  in  later  periods.  As  life  advances,  the 
fibres  become  redder,  more  distinct,  and 
stronger.  A  readiness  to  contract  is  manifested 
very  early,  but  it  is  not  till  maturity  that  these 
organs  are  able  to  maintain  contraction  for  any 
length  of  time.  They  suffice  well  for  the  quick 
and  buoyant  motions  of  the  lively  child,  but 
fail  in  those  violent  and  prolonged  exertions 
required  by  the  labours  of  manhood.  The 
form  of  the  muscles  changes  materially  in  the 
progress  of  years ;  thus,  they  swell  out  in  the 
middle,  and  occasion  a  great  difference  in  the 
proportions  of  the  limbs.  Those  portions  of  the 
locomotive  apparatus  attached  to  the  muscles 
and  articulations,  viz.  the  tendons  and  liga- 
ments, undergo  corresponding  changes.  In 
infancy  they  are  soft  and  gelatinous ;  gradually 


they  become  firmer,  their  gelatine  acquires 
a  more  glutinous  character,  and  the  membrane 
which  envelopes  them  is  more  condensed.  Every 
one  knows  the  different  products  obtained  by 
boiling  the  tendinous  parts  of  young  and  adult 
animals;  in  the  one  they  have  the  qualities  of 
jelly,  in  the  other  of  glue.  The  readiness  with 
which  the  joints  of  a  child  are  strained  or  dis- 
located is  likewise  well  known.  The  imma- 
ture condition  of  the  infant  is  strongly  marked 
in  the  ankles,  which  are  turned  inwards,  and 
would  never  suggest  the  use  to  which  the  feet 
are  to  be  applied,  but  for  our  familiarity  with 
the  change  that  afterwards  occurs.  The  car- 
tilages and  fibro- cartilages  are  subjected  to 
a  development  corresponding  to  that  of  the 
fibrous  tissue. 

Into  the  composition  of  the  vocal  appa- 
ratus we  know  that  muscular,  fibrous,  and 
cartilaginous  tissues  enter;  and,  as  these 
are  altered  by  age,  the  mechanism  which 
they  constitute  might  a  priori  be  expected 
to  suffer  similar  modifications.  The  larynx 
of  the  infant  is  small  and  almost  circular; 
consequently  the  lips  of  the  glottis  and 
the  superior  ligaments  are  very  short.  This 
configuration,  viewed  in  connection  with  the 
immaturity  of  the  muscular  tissue,  accounts  for 
the  shrill  wailing  cry,  which  is  the  only  vocal 
sound  produced  at  this  early  period  of  human 
existence,  and  the  only  one  required,  since 
the  quick  instinct  of  maternal  affection  can 
interpret  these  simple  notes  into  an  eloquent 
language.  No  very  appreciable  alteration  takes 
place  in  these  parts  at  the  time  when  speech  is 
acquired,  for  this  attainment  has  more  con- 
nection with  the  development  and  command  of 
the  muscles  of  the  pharynx  and  mouth,  as  well 
as  with  the  organ  of  intelligence,  which  enables 
the  human  being  to  discriminate  sounds  and  to 
imitate  them.  Fortunately  the  oral  and  pha- 
ryngeal  muscles  are  some  of  the  foremost  in 
development,  being  required  in  suction  and 
deglutition.  A  progressive  change  goes  on  in 
the  larynx,  though  it  is  not  very  evident  till  the 
period  of  puberty  in  the  male,  when  the  thyroid 
cartilage  is  elongated,  and  with  it  the  thyro- 
arytenoid  muscle.  At  this  epoch  occurs  the 
moulting  of  the  voice,  or  an  accession  of  gravity 
in  the  tones,  occasioned  by  the  elongation  of 
the  parts  just  mentioned.  The  projection  of 
the  pomum  Adami  takes  place  at  the  same 
time.  In  the  female  larynx  scarcely  any  change 
occurs,  and  the  voice  iii  consequence  remains 
acute.  We  have  already  spoken  of  the  facial 
bones  and  their  cavities,  parts  which  exercise 
a  very  decided  influence  on  the  sonorousness 
of  the  voice. 

We  must  now  hasten  to  the  consideration 
of  the  parts  employed  in  that  other  distin- 
guishing function  of  animals,  viz.,  sensation. 
There  are  two  grand  divisions  of  the  organs  of 
sensation,  those  which  we  understand,  and  those 
which  we  do  not.  The  former  consist  of  the 
various  kinds  of  animal  mechanism  whereby 
the  external  causes  of  sensation  are  modified,  the 
latter  of  the  nervous  substance  intermediate  to  the 
external  excitant,  and  that  state  of  consciousness 
which  we  denominate  sensation.  We  know 


AGE. 


71 


that  the  eye  collects  rays  of  light  and  con- 
centrates them  on  its  internal  surface,  but  are 
utterly  ignorant  of  the  changes  which  the  re- 
tina, the  optic  nerve,  and  the  brain  undergo  in 
producing  that  condition  of  our  sentient  exis- 
tence which  we  call  vision.  It  is  true  that  we 
are  aware  that  certain  states  of  these  parts  are 
incompatible  with  sight ;  but  why  they  are  so 
is  quite  beyond  our  knowledge.  We  are,  as  it 
regards  our  acquaintance  with  the  adaptation  of 
nervous  tissue  to  the  production  of  sensation, 
in  the  same  predicament  as  a  man  who  watches 
the  working  of  a  steam-engine,  and  knows  that 
a  certain  quantity  of  fuel,  of  water,  of  valvular 
compression,  &c.  is  necessary  to  its  motion, 
but  has  no  idea  of  the  laws  of  caloric,  vapori- 
zation, constitution  of  elastic  fluids,  &c.  Our 
science  demonstrates  the  fitness  of  the  external 
and  internal  ear  for  receiving,  propagating, 
multiplying,  and  diffusing  vibrations,  but  why 
the  contact  with  the  auditory  nerve  produces 
sound,  is  an  all  but  impossible  inquiry ;  as  well 
as  the  reason  why  the  sensation  may  be  absent 
when  the  organ  is  in  perfect  order,  and  the 
nerve  to  all  appearance  unchanged ;  or  why  the 
sensation  may  occur  without  vibrations,  as  in 
dreaming,  and  many  nervous  disorders.  The 
same  may  be  said  of  the  skin;  it  is  well 
adapted  for  coming  in  contact  with  the  points 
or  superficies  of  bodies,  but  who  can  say  why 
the  nerves  spread  over  it  occasion  certain  feel- 
ings ?  These  remarks  are  premised  merely  to 
shew  that  it  must  not  excite  surprise,  if  we  are 
unable  to  point  out  completely  the  changes 
which  age  produces  in  the  human  body,  corres- 
pondently  with  the  changes  of  its  sentient  fa- 
culties. 

It  has  already,  in  all  probability,  struck  the 
mind  of  the  reader,  that  the  great  develop- 
ment of  the  cerebral  system  in  the  infant  is 
inconsistent  with  the  principle  which  we  have 
been  endeavouring  to  demonstrate,  viz.,  that  the 
growth  of  the  human  body  consists  essentially 
in  the  elevation  of  the  organs,  subservient  to  the 
animal  functions,  from  a  rudimentary  state. 
The  more  we  grow,  the  smaller  is  the  proportion 
of  the  brain  to  the  rest  of  the  fabric.  But  it 
is  no  less  true  that  the  functions  of  the  brain 
grow  with  our  growth.  How  then  are  we  to 
reconcile  these  opposite  facts  ?  We  must  cer- 
tainly discard  the  opinion,  that  the  bulk  of  the 
organ  is  proportionate  to  its  power,  and  exa- 
mine the  composition  and  the  relations  of  its 
various  parts  to  each  other. 

Limited  as  our  knowledge  is  of  the  requisite 
conditions  of  nervous  substance  for  its  func- 
tion, we  are  notwithstanding  aware  of  two  ex- 
tremes of  softness  and  hardness,  which  comprise 
those  states  of  the  tissue  which  are  compatible 
with  the  exercise  of  its  peculiar  faculty.  Patholo- 
gists  well  know  that  ramollissement  and  indu- 
ration of  the  brain  may  produce  the  same  lesion 
of  function,  viz.,  abolition  of  sensation  ;  while  it 
is  equally  well  known  that  approximations  to 
the  same  conditions  will  produce  impairment  of 


but  particularly  as  it  regards  the  functions  of 
the  nervous  system,  is  matter  of  uiu\,  i 
servation.     It  might  thru  ,}  /,/•/<*/•/  i 
that  one  of    the  changes  in  cerebral   -m\\tli 
would  be  a  tendency  to  a  certain  intt-niK  ,li,,t<.- 
degree  of  consistence,  and  this  is  found  u<  m.illy 
to  be  the  case. 

From  a  careful  comparison  of  the  size  and 
weight  of  the  brain  at  different  ages,  it  was  ascer- 
tained by  the  Wenzels,  and  is  demonstrated  in 
tables  contained  in  their  work,De  Pen  it  i. . 
bri  Structura,*  that  although  the  organ  increases 
very  sligthly  in  bulk  after  the  third  year,  its 
weight  does  not  attain  its  maximum  till  after 
the  seventh,  so  that  up  to  this  time  there  is  a 
progressive  increase  of  density.  After  the 
seventh  year  there  is  no  great  difference  either 
in  size  or  density.  (The  size  of  the  brain  must 
not  be  confounded  with  that  of  the  head,  which 
after  the  period  that  we  speak  of,  is  detenu  m.<l 
by  the  growth  of  the  external  table  of  the  skull, 
correspondently  with  the  projection  of  the  bones 
of  the  face.)  There  must,  therefore,  be  some  other 
change  than  that  of  density,  to  account  for  the 
augmentation  of  intellectual  power  in  the  suc- 
ceeding periods,  and  herein  our  information  is 
most  at  fault.  Nevertheless  we  are  not  altogether 
without  intimations  of  organic  changes.  The 
majority  of  physiologists  are  agreed  that  the 
function  of  the  cortical  substance  is  of  a  higher 
character  than  that  of  the  medullary.  The 
lower  we  descend  in  the  animal  series,  the  less 
we  find  of  the  cineritious  matter,  which  is  not 
apparent  at  all  in  the  invertebrata,  nor  indeed 
in  fishes.  It  is,  therefore,  not  without  proba- 
bility conceived  that  this  matter  is  more  imme- 
diately concerned  in  thought ;  and,  conformably 
with  this  view,  we  find  its  colour  more  strongly 
marked,  as  boyhood  stretches  on  to  manhood.-)- 
We  may  mention  as  corroborative  of  this  cir- 
cumstance, that  M.  Foville,  an  eminent  in- 
vestigator of  the  pathology  of  mental  diseases, 
asserts  that  the  principal  lesions  in  the  brains 
of  maniacs  occur  in  the  grey  tissue.}  The 
convolutions  again  afford  us  some  hints  upon 
the  subject  before  us.  Intelligence  is  in  direct 
proportion  to  their  extent,  and  we  accordingly 
find  that  these  parts  are  deeper  as  age  advances. 
As  the  existence  of  the  posterior  cerebral  lobes, 
and  of  the  corpus  rhomboideum  in  the  cere- 

*  See   the    notes   to  Milligan's  Translation   of 
Magendie's  Physiology. 

f  This  observation  refers  to  the  cineritious  raal 
of  the  convolutions.   In  certain  other  parts  this  sub- 
stance diminishes  after   birth.     Thus,  in  the  full- 
erown  fretus,  the  medulla  oblongata  is  grey  through- 
out, but  soon  begins  to  whiten,  first  .in  the  corpora 
pyramidalia,    and  afterwards  in  the  ohvana.     fl 
outer  surface  of  the  tuber   annulare,  and    of  the 
crura  cerebri,  is  also  grey  at  the  commencement  of 
extra-uterine  life;    but  they  lose  this  colour  ai 
a  few  weeks.      In  the  thalami  optici  and  torpor; 
striata  there  is  no   distinction  o*  white  and  grev 
matter,  the  latter  alone  being  visible      See  Meckel. 
Manuel    d'Analomie,     t.   n.    p.    717.        RUB 
functions  of  these  parts  in  mature  age  are  better 
understood  than  at  present    ,t  would  ^  useless  to 
l    relatioi 


this  faculty.     Now  in  infancy  the  brain  is  ex-  culate  upon  the  physiological  relation*  of 

tremely  soft,  almost   pultaceous,  while    in    old      changes  which  they  undergo  in  earlier  peri 


tremely  soft,  almost  pultaceous,  while  in 
age  it  is  extremely  hard  in  comparison,  and  the 
similarity  of  the  two  ages  in  many  respects 


^DJct.de  Med.'ct  Chir. 
tion  Mcntale. 


Pratique,  art.   Ali6na- 


7'2 


AGE. 


bellum,  is  observed  only  at  the  top  of  the 
animal  scale,  we  might  expect  that  in  the  pro- 
gress of  age  there  would  be  a  change  in  the 
relations  of  these  parts  to  the  whole  mass,  but 
we  cannot  find  that  any  researches  have  been 
prosecuted  in  elucidation  of  these  points. 

Most  of  what  we  have  predicated  of  the  pro- 
gressive actions  in  the  brain,  is  likewise  appli- 
cable to  the  cerebellum  and  spinal  marrow, 
and  nerves.  The  latter  parts,  however,  are 
more  forward  in  their  organization,  being  de- 
voted to  the  more  primitive  functions  of  sensa- 
tion and  voluntary  motion,  while  the  former  is 
the  instrument  of  the  faculties  more  eminently 
intellectual.  The  proportion  of  the  cerebellum 
to  the  brain  at  birth,  is,  according  to  Meckel, 
as  1-23;  the  former  weighing  nearly  3£  drachms, 
the  latter  9  or  10  oz.  A  month  after  birth  the 
ratio  is  V17;  after  six  months,  1-8. 

The  proportion  between  the  spinal  marrow 
and  the  brain  at  birth,  and  for  five  months 
after,  is  1-107  or  even  1-112  ;  the  brain  at  the 
former  period  weighing  9oz.  4dr.,  and  the 
spinal  marrow  45gr.,  while  at  the  latter  period 
the  cerebral  organ  weighs  21oz.,  and  the  spinal 
l£dr.  In  the  foetus  of  five  months  the  propor- 
tion is  1-63,  of  three  months  VI 8.  In  the 
adult  it  is  1-40.  The  diminishing  ratio  of  the 
brain  to  the  spinal  marrow  is  in  obvious  har- 
mony with  the  elongation  of  the  vertebral 
column,  and  with  the  general  growth  of  the 
members.  The  medulla  oblongata  is  propor- 
tionally larger  in  early  than  in  advanced  life ; 
the  corpora  pyramidalia  and  olivaria  being  dis- 
tinct and  prominent;  a  fact  which  corresponds 
with  the  development  of  the  brain. 

The  longitudinal  dimensions  of  the  corpora 
quadrigemina  at  birth  exceed  those  of  the  adult 
period ;  after  the  former  period  they  increase 
only  in  their  transverse  diameter. 

The  concretions  of  the  Pineal  glands  have  not 
begun  to  be  formed  till  the  seventh  year.  They 
are  sometimes  wanting  in  very  advanced  age, 
according  to  the  observations  of  Meckel  and 
the  Wenzels,  which  we  have  had  oppor- 
tunities of  verifying  by  our  own  dissections. 
The  number  of  these  bodies  increases  with  the 
progress  of  life,  and  their  colour  is  paler  in 
youth  and  old  age  than  in  intermediate 
periods.* 

So  much  then  for  the  nervous  organs  of 
sensation.  Our  attention  must  next  be  directed 
to  the  mechanism  intermediate  to  the  nerves, 
and  the  excitants  of  sensation.  The  simplest 
kind  of  sensation  is  that  which  informs  or  re- 
minds us  that  we  are  possessed  of  bodily  parts, 
such  as  members  and  internal  organs.  The  me- 
chanism employed,  if  there  be  any,  is  unknown. 
Nerves  are  distributed  through  the  tissues,  we 
feel  those  tissues,  and  conclude  that  these  feel- 
ings result  from  relations  between  the  nerves  and 
the  other  textural  molecules  with  which  they  are 
in  contact.  These  feelings  must  of  course  vary 
with  age  because  the  tissues  alter,  but  whether 
the  susceptibility  is  increased  we  cannot  say, 
and  only  venture  to  remark  that  the  proba- 

*  For  further  details  see  the  works  of  Meckel  and 
Tiedemann. 


bility  of  this  being  the  case  is  suggested  by  the 
fact,  that  adults  are  more  subject  to  perver- 
sions of  sensibility  than  children;  witness  the 
various  nervous,  hypochondriacal,  and  hys- 
terical disorders  with  which  adults  are  almost 
exclusively  visited. 

The  next  order  of  sensations  in  respect  of 
simplicity  are  those  of  tact,  or  those  by  which 
we  are  made  acquainted  that  foreign  bodies 
are  in  contact  with  our  skin.  It  is  perhaps  in 
some  respects  only  a  modification  of  the  first- 
mentioned  sensation,  but  it  requires  the  pre- 
sence of  something  not  belonging  to  us.  It  is 
true  that  other  parts  than  the  skin  may  convey 
the  notion  of  an  external  body  being  applied  to 
them,  but  they  do  not  afford  any  perception  of 
the  qualities  of  the  body  ;  it  is  merely  the 
affection  of  themselves  which  is  produced  by 
that  body.  We  are  aware  that  all  sensation 
may  be  analysed  in  the  same  manner  with 
similar  results,  but  it  is  enough  for  our  present 
purpose  that  the  sensation  excited  on  the  skin  is 
less  selfish,  if  we  may  use  the  term  in  this  sense, 
and  ought  to  be  so,  in  order  that  it  may  serve 
its  office  of  supplying  some  knowledge  of  the 
external  world.  Doubtless  the  organization  of 
the  epidermis  and  of  the  skin  itself,  as  well  as 
the  greater  distribution  of  nervous  matter,  occa- 
sion the  difference.  The  dermoidal  tissue  in 
modifying  the  external  cause  stands  in  the  same 
relation  to  the  nerves  of  tact,  as  the  eye  to  the 
optic  nerve,  or  the  nose  to  the  olfactory.  The 
organ  of  tact  is  affected  by  age;  the  skin  in 
very  early  life  appears  less  susceptible  of  im- 
pressions, and  differs  in  its  tissue,  the  papillae 
being  less  developed.  A  change,  however,  is 
soon  effected  in  this  respect,  and  as  we  advance 
towards  manhood,  it  becomes  less  gelatinous 
and  more  fibrous.  It  must  be  confessed,  how- 
ever, that  the  modifications  which  it  undergoes 
in  reference  to  its  function  of  sensation,  are  not 
well  defined.  This  circumstance  is  owing  to 
the  variety  of  sensations  to  which  it  ministers, 
such  as  (in  addition  to  what  we  have  men- 
tioned) feelings  of  heat  and  cold,  dryness 
and  moisture,  &c.  and,  secondly,  to  its  being 
also  an  organ  for  other  and  very  different  func- 
tions, such  as  transpiration,  secretion,  and  ab- 
sorption. 

Touch  has  a  far  more  complicated  mechanism 
than  tact.  It  is  one  of  the  senses  properly  so 
called,  or  the  special  senses,  and  like  the  others 
of  its  class  is  distinguished  by  its  requiring  the 
assistance  of  muscles.  Its  sensations  are  com- 
pounded of  tact  and  muscular  resistance,  and 
the  organ  is  that  wonderful  instrument  the  hand. 
The  imperfect  state  of  this  organ  in  infants  must 
have  been  noticed  by  every  one  ;  it  is  generally 
closed  and  capable  of  grasping  but  very  feebly ; 
at  all  events  a  long  time  occurs  before  the 
little  being  learns  to  arrange  the  sensitive 
tips  of  the  fingers,  and  to  adjust  the  thumb  in 
such  a  manner  as  to  ascertain  with  nicety  the 
form,  consistence,  and  other  properties  of 
bodies.  Whether  the  skin  is  less  sensitive  in 
these  subjects  we  cannot  say,  but  it  is  quite 
certain  that  the  muscles,  which  effect  the  digital 
motions  alluded  to,  are  not  developed  any  more 
than  those  in  other  parts  of  the  body.  Fine- 


AGE. 


ness  of  touch,  tactus  eruditus,  is  one  of  the 
most  difficult  attainments  of  manhood. 

Concerning  the  alterations  in  the  olfactory 
apparatus  we  have  already  spoken,  when  the 
development  of  the  facial  bones  was  under 
consideration.  The  sense  of  smell  is  mani- 
fested pretty  early,  but  there  can  be  no  great 
precision  and  nicety  in  its  exercise,  both  from 
defect  of  surface,  and  from  the  want  of  mus- 
cular power  and  command,  in  adjusting  the 
quantity  and  impetus  of  the  air  that  conveys 
the  odorous  particles.  Thus,  some  agents  are 
only  appreciated  by  a  sudden  inhalation  through 
the  nostrils,  as  if  to  bring  the  particles  with  a 
certain  degree  of  force  upon  the  Schneiderian 
membrane.  This  art  the  child  does  not  under- 
stand. 

Taste  being  a  sense  so  essential  to  the  main- 
tenance of  the  system,  whether  by  inducing  the 
animal  to  take  the  trouble  of  eating,  or  by 
warning  him  of  improper  aliment,  is  mani- 
fested very  early.  The  usual  description  of  the 
mechanism  of  taste  would  give  just  cause  for 
questioning  what  was  said  respecting  the  ne- 
cessity of  a  co-operation  of  muscular  action 
with  the  five  senses.  Taste  is  described  as 
the  result  simply  of  the  application  of  sapid 
bodies  to  the  tongue,  palate,  velum  palati,  &c. 
But  these  bodies  excite  no  sensation  without 
the  aid  of  muscles.  A  certain  degree  of  com- 
pression is  necessary,  which  is  accomplished 
by  pressing  the  tongue  against  the  roof  of  the 
mouth.  Any  one  may  assure  himself  of  this  fact 
by  placing  a  strongly  flavoured  substance  on 
the  tongue  when  projected  from  the  mouth ; 
no  taste  wrill  ensue  till  the  member  is  with- 
drawn and  then  pressed  against  the  palate. 
This  observation  applies  not  only  to  the  tongue 
but  also  to  the  palate  itself,  and  that  sensitive 
surface  the  velum.  In  each  instance,  however, 
the  effect  may  be  imitated,  by  compressing 
with  the  finger  the  part  where  the  substance  is 
applied. 

Taste  must  undergo  a  progressive  develop- 
ment correspondently  with  the  muscular  or- 
gans. It  is,  to  say  the  least,  very  doubtful  if 
a  child  could  perform  those  delicate  manoeuvres 
of  the  tongue  and  palate,  which  are  practised 
by  gourmands  or  professed  wine-tasters.  There 
is  something  more  than  this  muscular  action, 
however,  to  be  taken  into  consideration.  The 
more  refined  flavours  are  probably  felt  and 
estimated  by  the  lining  membrane  of  the  nasal 
passages.  It  is  common  to  remark  that  the 
scent  of  a  substance  is  similar  to  its  taste,  but 
in  all  probability  the  two  sensations  are  iden- 
tical ;  for  the  taste  in  question  is  not  perceived 
if  the  nostrils  be  closed ;  witness  the  abolition 
of  taste  during  a  catarrh.  If  therefore  so  close 
a  connection  exists  between  the  two  senses, 
it  is  clear  that  the  development  of  the  organi- 
zation belonging  to  the  one  must  influence  the 
other  function  ;  and  it  has  been  already  pointed 
out  that  the  olfactory  surface  increases  with 
growth. 

The  new-born  infant  is  probably  all  but  deaf; 
even  the  loudest  sounds  produce  no  sensible 
impression.  The  nurse's  lullaby,  therefore,  is 
for  some  time  superfluous ;  by  degrees,  how- 


73 


ever,  the  shrill  tones,  of  which  such  strain,  for 
the  most  part  consist,  begin  to  be  a|>i>iv,,.(i,,l  • 
the  precise  period  however  ur  ,1,,  ,„„  u,^.' 
In  correspondence  with  this  ohtusity  \M-  (i,,,! 
the  organ  incomplete,  but  tin-  incompl 
has  reference  rather  to  the  external  th;m  to  t|1(. 
internal  ear.  Thus  the  pinna  is  very  i 
and  therefore  unfitted  for  collet  tin-  viliiMtions  • 
the  same  may  be  said  of  the  meatus  auditorial! 
In  like  manner,  the  membrana  tynipan, 
oblique,  and  scarcely  more  than'a  continuation 
of  the  superior  surface  of  the  meatus,  and  thus 
little  calculated  to  receive  the  vibrations.  Tin  M. 
parts  are  also  covered  with  a  .soft  matter  very 
unfavourable  to  vibrations ;  the  tympanum  is 
very  small,  and  the  mastoid  cells  do  not  .AM. 
In  the  progress  of  age  all  these  parts  gradually 
increase  in  hardness,  and  consequently  are  bet- 
ter adapted  to  their  function.  There  are  mus- 
cles attached  to  this  sense  also,  but  we  are 
deficient  in  observations  on  their  degree  of  de- 
velopment, though  we  may  infer  their  condition 
from  analogies  in  the  rest  of  the  muscular 
system. 

Lastly,  we  come  to  the  organ  of  vision,  of 
which,  however,  there  is  not  much  to  be  said. 
The  differences  between  the  visual  organ  in  the  in- 
fant and  in  the  adult  consist  more  in  degree  than 
in  kind;  thus  the  sclerotic  membrane  is  less 
elastic,  and  the  cornea  is  less  conical,  in  conse- 
quence of  the  smaller  quantity  of  aqueous  hu- 
mour; (the  greater  thickness  of  this  coat  is  pro- 
duced by  the  serosity  contained  between  its  la- 
minae;) thecrystalline  lens  is  lessdense, but  more 
convex  in  form.  The  pigmentum  is  in  smaller 
quantity  at  birth  than  afterwards;  while  the  retina 
is  thicker  and  more  pulpy  than  in  more  ad- 
vanced periods.  The  yellow  tint  of  the  foramen 
of  Soemmering  does  not  become  visible  till 
some  time  after  birth,  but  deepens  with  the 
progress  of  life,  till  the  stage  of  decline, 
when  it  grows  paler.  It  has  been  ascertained 
that  perfect  images  are  formed  on  the  retina ; 
and  yet  for  the  first  few  days  the  child  gives  no 
indication  of  visual  sensation,  and  when  objects 
appear  to  attract  its  attention,  they  are  only 
those  which  are  vividly  illuminated.  The  de- 
ficiency therefore  must  exist  in  the  optic  nerve, 
though  we  are  ignorant  of  the  organic  condition 
on  which  this  insensibility  is  dependent.  We 
observe,  moreover,  that  the  eye  is  much  more 
passive  than  in  the  adult,  that  it  follows  the 
motion  of  luminous  bodies,  or  is  fixed  upon 
them  with  little  or  no  apparent  interference  of 
the  will.  This  muscular  incompleteness,  then, 
tallies  with  what  we  have  noticed  with  respect  to 
the  other  senses.  The  eye  is  known  in  its  advance 
towards  manhood  to  increase  in  the  capability 
of  adapting  itself  to  different  distances;  but  as 
we  are  ignorant  of  the  mechanism  made  use  of 
for  this  purpose,  it  is  useless  to  look  for  cor- 
responding organic  alterations.  We  must  not 
omit  to  notice  those  appendages  to  the  appara- 
tus of  vision,  called  eyebrows,  which  become 
much  more  prominent  as  life  advances,  by  the 
development  of  the  frontal  sinuses,  and  are 
therefore  belter  adapted  for  shading  the  eyes. 

The  generative  apparatus  is  situated  inter- 
mediately to  the  animal  and  the  organic  s\  >t«  in. 


74 


AGE. 


The  evolution  of  the  organs  connected  with  this 
function  marks  the  age  of  puberty;  and  the 
changes  in  which  this  evolution  consists,  both 
in  the  male  and  in  the  female,  are  too  well 
known  to  require  their  specification  here.  The 
influence  of  this  development  on  the  mental 
and  moral  characters  of  either  sex,  is  likewise 
sufficiently  familiar  even  to  the  most  superficial 
observer. 

The  human  being  is  related  with  the  external 
world  passively  and  actively,  independently  of 
those  organic  actions  and  reactions  that  are 
constantly  occurring  in  his  system  with  regard 
to  outward  agents.  He  derives  perceptions 
from  objects  about  him,  and  he  reacts  on  them 
by  his  power  of  muscular  motion.  But  in  his 
growth  we  mark  that  the  perfection  of  those 
organs,  which  are  scarcely  more  than  passive 
in  his  relative  life,  advances  much  more  ra- 
pidly than  those  which  enable  him  to  take  a 
more  active  part.  Thus  the  eye  and  the  ear 
attain  a  certain  maturity  of  organization  and 
function,  long  before  the  bones  and  muscles, 
which  officiate  in  locomotion.  The  bones  and 
muscles  connected  with  the  organs  of  sensation, 
and  therefore  partaking  of  the  passive  character, 
are  also  equally  forward  in  their  development. 
What  is  the  probable  final  cause  of  this 
arrangement?  If  all  our  voluntary  motions 
were  the  immediate  consequences  of  our  sen- 
sations, as  some  of  them  undoubtedly  are, 
such  as  those  which  close  the  dazzled  eyes,  or 
refuse  the  bitter  food,  or  withdraw  from  pain- 
ful contact;— if  all  these  followed  directly  on 
sensations,  it  would  indeed  be  a  strange  ano- 
maly, if  the  systems  that  belong  to  each  were 
not  precisely  on  the  same  level  of  development. 
But  this  is  not  the  case ;  all  the  more  impor- 
tant motions,  important  as  it  regards  that  world 
in  which  man  exists,  as  an  intelligent  and 
social  creature,  though  less  so  as  it  respects  his 
individual  being,  are  the  results  of  a  mental 
condition,  no  less  distinct  from  sensation  than 
from  muscular  motion.  This  state  is  desire,  or 
as  it  is  commonly  called  when  the  antecedent 
of  action,  will  or  volition.  Probably  no  men- 
tal state  is  more  simple  than  this,  and  it  may 
follow  any  other.  It  is  therefore  the  more 
necessary  that  it  should  be  preceded  by  such 
intellectual  changes  as  will  give  it  a  right 
direction ;  in  other  words,  that  it  should  come 
under  the  dominion  of  certain  faculties.  But 
in  early  life  the  faculties  to  which  we  allude , 
are  very  imperfectly  developed;  those  only 
have  attained  any  thing  like  maturity  which 
are  in  immediate  relation  with  the  senses; 
such  are  perception,  memory,  association,  and 
imagination ;  while  the  reflective  faculties, 
such  as  comparison,  reasoning,  abstraction,  all 
in  fact  that  constitute  man  a  judicious  expe- 
rienced agent,  are  rudimentary.  The  conse- 
quence is  that  the  desires  or  volitions  are  pro- 
verbially vain  and  dangerous.  Let  us  observe 
a  child  of  seven  years  old  ;  his  senses  are  suffi- 
ciently acute  for  all  ordinary  purposes,  although 
they  are  deficient  in  precision  and  delicacy; 
he  has  seen  many  attractive  objects,  he  has 
heard  many  wouderful  stories,  and  tasted  many 
exquisite  delights ;  he  remembers  them  vividly, 


he  associates  them  rapidly,  and  often  in  shapes 
very  different  from  those  in  which  they  were 
formerly  combined.  Desires  follow  which 
would  prompt  him  to  execute  the  most  ridicu- 
lous and  mischievous  schemes.  But  happily 
the  muscular  system,  by  which  alone  he  could 
accomplish  them,  is  too  immature  and  feeble 
for  his  puerile  purposes.  Here  then  is  the 
final  cause  that  we  were  in  search  of;  the  active 
corporeal  functions  of  relation  must  not  ad- 
vance beyond  the  governing  faculty  of  the 
mind. 

But  why,  it  might  hastily  be  asked,  should 
not  the  senses,  the  mental  faculties,  and  the 
motive  powers,  all  have  been  equally  deve- 
loped? The  question  is  absurd,  if  we  consider 
but  a  moment  the  manner  by  which  the  mind 
accomplishes  its  growth  ;  that  its  higher  powers 
result  from  the  accumulation  of  innumerable 
sensations,  by  which  in  fact  the  former  are 
nourished  and  exercised. 

We  shall  now  introduce  a  brief  account  of 
some  researches  upon  the  height,  weight,  and 
strength  of  the  human  body,  at  different  ages, 
prosecuted  by  M.  Quetelet,  of  Brussels.  Not 
having  room  for  the  numerical  tables,  or  the 
particular  observations,  from  which  his  general 
conclusions  are  derived,  we  must  content  our- 
selves with  a  statement  of  the  latter,  and  refer 
those  of  our  readers  who  may  be  desirous  of 
seeing  the  former,  to  the  author  himself.  His 
deductions  as  to  the  growth  of  human  stature 
are  as  follows:  (1)  the  growth  is  most  rapid 
immediately  after  birth ;  it  amounts  in  the  first 
year  of  infancy  to  about  two  decimetres 
(nearly  eight  inches.)  (2)  The  growth  dimi- 
nishes as  the  child  advances  towards  the 
fourth  or  fifth  year;  thus,  during  the  second 
year  his  increase  of  height  is  only  half  what  it 
was  the  first  year,  and  during  the  third  year  it 
is  not  more  than  one-third.  (3)  After  the 
fourth  or  fifth  year,  the  stature  increases  pretty 
regularly  until  the  age  of  sixteen,  and  the  an- 
nual growth  is  about  fifty-six  millim,  (two  inch.) 

(4)  After  puberty  the   stature  still  increases, 
though  slightly ;  thus,  from  the  sixteenth  to  the 
seventeenth  year,   the  increase  is  about  four 
centim.  (If  inch);   and  in  the  two  following 
years,  only  two  centim,  and  a  half  (one  inch.) 

(5)  The  stature  does  not  appear  to  be  quite 
completed  even  at  the  age  of  twenty-five. — 
These  observations  refer  only  to  absolute  growth, 
but  if  the  annual  increase  of  stature  be  com- 
pared with  the  height  which  has  been  attained, 
it  will   be  found  that  the  infant,  after  birth, 
increases   in    the   first    year  by   two  fifths  of 
his   height;    in   the   second   by  one-seventh; 
in  the  third  by  one-eleventh;    in  the   fourth 
by   one-fourteenth;    in  the   fifth    by   one-fif- 
teenth ;   in   the  sixth  by  one-eighteenth ;  &c. 
so  that  the  relative  growth  continually  dimi- 
nishes after  birth. 

In  addition  to  these  statements  M.  Quetelet 
has  ascertained  that  the  rules  of  growth  are  not 
the  same  in  both  sexes;  1st,  because  the  female 
at  birth  is  less  than  the  male;  2dly,  because 
her  development  is  completed  earlier;  3dly, 
because  her  annual  growth  falls  short  of  that  of 
the  male.  It  appears  likewise  that  the  stature 


AGE. 


of  persons  living  in  towns,  taken  at  the  age  of 
nineteen,  exceeds  that  of  residents  in  the  coun- 
try by  two  or  three  centim  (1  or  l\  inch);  and 
that  the  children  of  persons  in  easy  circum- 
stances, and  those  of  studious  habits,  are  gene- 
rally above  the  middle  height.* 

A  memoir  by  the  same  author  devoted  to  an 
examination  of  the  weight  of  the  human  subject 
at  different  ages,  contains  a  series  of  interesting 
conclusions,  from  which  we  select  the  following. 
(1.)  At'  the  period  of  birth  there  is  an  inequality 
both  as  to  weight  and  to  stature,  in  the  two  sexes  ; 
the  medium  weight  of  males  being  3  kil.  20, 
(rather  more  than  7  Ibs.),  that  of  females  2  kil. 
91,  (about  6£  Ibs.);  the  height  of  the  former 
Om.  496,  (about  19  inch.);  that  of  the  latter 
Cm.  483,  (about  18  inch.)  (2.)  The  weight  of 
the  infant  diminishes  the  first  three  days  after 
birth,  and  does  not  begin  to  increase  till  the 
second  week.  (3.)  At  the  same  age  the  male  is 
generally  heavier  than  the  female;  it  is  only 
about  the  twelfth  year  that  their  weights  are 
equal.  Between  the  first  and  eleventh  year  the 
difference  of  weight  is  fiom  1  kil.  to  1  kil.  and 
a  half;  between  sixteen  and  twenty,  about  6  kil. 
and  after  this  period  from  8  to  9  kil.  (4.)  At 
full  growth  the  weight  is  almost  exactly  twenty 
times  what  it  was  at  birth,  while  the  stature  is 
only  about  three  and  a  quarter  more  than  it 
was  at  that  period.  This  holds  good  with  both 
sexes.  (5.)  In  old  age  both  sexes  lose  about 
6  or  7  kil.  of  their  weight,  and  7  centim.  of 
their  height.  (6.)  During  the  growth  of  both 
sexes,  we  may  reckon  the  squares  of  the  weights, 
at  the  different  ages,  as  proportional  to  the  fifth 
powers  of  the  heights.  (7.)  After  full  growth 
in  each  sex,  the  weights  are  very  nearly  as  the 
squares  of  the  heights.  (From  the  two  prece- 
ding statements  it  may  be  deduced  that  the 
increase  in  the  longitudinal  direction  exceeds 
that  in  the  transverse,  including  in  the  latter 
both  width  and  thickness.)  (8.)  The  male  at- 
tains his  maximum  weight  towards  the  fortieth 
year,  and  begins  to  lose  it  sensibly  towards  the 
sixtieth.  The  female  does  not  attain  her  maxi- 
mum weight  till  about  the  fiftieth  year.  (9.) 
The  weights  of  full-grown  and  well-formed 
persons  vary  in  a  range  of  about  1  to  2,  while 
the  heights  vary  only  from  1  to  1$.  This  state- 
ment is  deduced  from  the  following  table  :f 


Male  weight 
Female 


Male  stature 
Female    . 


Maximum. 

Minimum. 

Medium. 

KIL. 

KIL. 

KIL. 

98.5 

49.1 

63.7 

93.5 

63.7 

55.2 

MET. 

MET. 

MET. 

1.990 

1.740 

1.684 

1.740 

1.408 

1.579 

*  Recherches  sur  la  loi  de  la  Croissance  de 
I'Homme,  par  M.  Quetelet.  Annales  d'Hygiene 
Publique,  &c.  t.  vi.  p.  89. 

t  Ann.  d'Hygiene,  t.  x.  p.  27.  To  the  above 
memoir  M.  Villerme  has  appended  some  extracts 
from  manuscript  notes  found  among  the  papers  of 
M.  Tenon,  and  written  about  the  year  1783.  They 
contain  observations  which  correspond,  in  many  re- 
spects, with  those  of  Quetelet. 


The  last  researches  of  this  industrious  ob- 
server have  been  devoted  to  the  muscular  p. 
of  man  at  different  ages,  and  have  Wn  hm 
very  recently  published.  In  the  course  of  Ins 
memoir  he  refers  to  two  tables;  one  statin  -  tin- 
relative  power  of  draught  (la  force  r6nale),  at 
the  several  periods ;  the  other,  the  relative  ma- 
nual strength  (la  force  manuelle) ;  in  each  > 
estimated  by  the  dynamometer.  The  results 
are  very  much  what  might  be  expected  a  priori. 
It  appears  that  the  maximum  of  the  "  force 
renale  "  is  at  the  age  of  twenty-five  ;  and  that 
the  difference  in  the  extent  of  this  kind  of  mus- 
cular power  between  males  and  females,  is  less 
during  childhood  than  at  the  adult  age.  Thus, 
in  the  former  period  the  male  surpasses  the 
female  by  one-third,  towards  puberty  by  one- 
half;  and  at  full  growth,  his  strength  is  double 
that  of  the  other  sex.  The  manual  force  is 
greatest  at  the  age  of  thirty,  and  at  all  ages  is 
greater  in  the  male  than  in  the  female  ;  before 
puberty,  in  the  ratio  of  3  :  2,  after  this  period, 
in  the  ratio  of  9:5.  The  average  manual 
strength  of  a  man  is  equivalent  to  89  kil.  and 
exceeds  his  weight  by  19  kil.,  so  that  he  might 
support  himself  by  his  hands  only,  even  with  a 
considerable  weight  attached  to  his  feet.* 

This  and  the  preceding  memoirs,  we  are 
told  by  M.  Quetelet,  are  extracted  from  a  work 
which  he  is  about  to  publish,  entitled  "  Sur 
I'Homme  et  le  developpement  de  ses  faculte"s ; 
ou,  Essai  de  Physique  Sociale."  We  need 
scarcely  add  that  we  are  justified  inspecting 
from  the  specimens  already  presented  to  us,  a 
series  of  valuable  and  highly  interesting  facts, 
together  with  deductions  of  no  ordinary  im- 
portance and  originality. 

Having  thus  briefly  traced  the  changes  that 
precede  maturity,  we  may  ask  what  is  it  that 
prevents  the  processes  of  growth  from  advancing 
at  the  same  rate  as  they  have  hitherto  done  ? 
Why,  so  long  as  they  are  undisturbed  by  dis- 
ease or  unnatural  circumstances,  should  they 
not  advance  ad  infinitum,  or  at  least  why 
should  they  not  raise  man  to  the  strength  and 
dimensions  which  poets  have  fabled  in  their 
Titans  ?  The  same  food,  the  same  atmosphere, 
the  same  light  and  heat,  the  same  electric 
agencies,  by  which  the  organs  have  been  main- 
tained or  excited,  are  still  around  them  and 
exerting  their  influence.  Why,  then,  should 
they  never  transcend  a  certain  point?  Why 
should  the  stature,  however  much  it  may  vary 
between  a  Boruwlaski  and  an  O'Brien,  yet 
never  rise  above  a  certain  measure  ?  Why  does 
the  strength  never  exceed  the  powers  of  a  Milo 
or  a  Desaguliers,  or  the  intellect  surpass  the 
limits  of  Aristotle,  Shakspeare,  or  Newton? 
These  are  interesting  but  impossible  problems. 
If  we  say  that  a  certain  quantum  of  vital  power 
is  allotted  to  the  growth  of  man,  and  that  while 
a  portion  is  expended  in  raising  him  to  matu- 
rity, the  residue  must  be  husbanded  for  con- 
ducting him  through  the  remaining  portion  of 
his  duration,  else  he  might  suddenly  stop  short 

*  Ann.  d'Hygiene,  &c.  Oct.  1834,  t.  xii.  p.  294. 


AGE. 


in  his  career  without  passing  those  stages  that 
prepare  him  for  the  cessation  of  his  existence  ; 
— what  do  we  gain  by  such  an  explanation  ? 
Nothing ;  for  the  term  vital  power  which  we 
employ  is  but  a  hypothetical  cause,  or  if  more 
closely  examined,  is  scarcely  even  this ;  it  is 
but  an  abstract  term  applicable  to  a  number  of 
actions  that  do  not  occur  in  the  inorganic 
world.  The  vital  power  of  a  body  is  but  the 
collective  manifestation  of  its  vital  actions,  and 
to  say  therefore  that  only  a  certain  quantum  of 
vital  power  is  inherent  in  it,  is  but  to  express 
in  other  words  the  simple  fact  that  those  actions 
are  circumscribed.  Discarding  this  explana- 
tion, shall  we  say  that  the  fact  must  be  referred 
to  some  deficiency  in  the  media  of  the  being's 
existence;  that,  although  the  aliment,  the  air, 
the  light  and  caloric  are  competent  to  the  pro- 
duction of  a  certain  degree  of  growth,  they 
cannot  extend  it,  and  that,  were  their  conditions 
different,  the  animal  development  would  be 
more  perfect.  It  is  easy  perhaps  to  suppose 
this,  but  we  do  not  see  how  it  can  be  proved, 
nor  indeed  that  existing  analogies  favour  it. 
On  the  surface  of  our  globe  there  is  every 
variety  in  the  temperature,  in  the  humidity,  and 
in  the  electric  conditions  of  the  atmosphere, 
and  every  diversity  in  the  articles  of  food  em- 
ployed; in  more  limited  spheres  there  are  the 
greatest  diversities  in  these  several  respects 
produced  artificially  by  the  various  occupations 
of  mankind  ;  and  although  we  find,  both  among 
races  and  individuals,  great  varieties  of  deve- 
lopment, which  may  occasionally  be  traced  to 
some  relation  with  the  media  in  which  they 
live,  these  varieties  are  by  no  means  in  propor- 
tion to  the  differences  of  the  media,  and  in  the 
majority  of  cases  the  former  are  independent 
of  the  latter.  In  the  temperate  zone,  with  a 
due  proportion  of  animal  and  vegetable  diet, 
man  appears  to  attain  his  most  perfect  deve- 
lopment, and  with  however  great  skill  he 
adapts  these  circumstances,  he  never  surpasses 
a  certain  point,  and  from  what  we  know  of  his 
physiology  no  great  alteration  in  any  one  of  the 
external  stimuli  of  his  existence  could  be  tole- 
rated. A  different  proportion  of  the  oxygen, 
nitrogen,  and  carbon  in  the  atmosphere,  we 
know  full  well  to  be  noxious ;  a  larger  or 
smaller  quantity  of  aqueous  vapour  suspended 
in  it  will  occasion  many  well-known  maladies ; 
the  same  may  be  said  of  alterations  in  the  ba- 
lance of  the  electricity  that  surrounds  us.  Great" 
extremes  of  heat  and  cold  may  be  borne  for 
awhile,  but  it  is  obvious  that  they  are  not  so 
well  adapted  to  a  healthy  state  of  the  system, 
and  therefore  to  its  growth,  as  intermediate  de- 
grees ;  and  consequently  it  is  not  easy  to  con- 
ceive any  degree  either  above  or  below  these 
limits  consistent  even  with  existence.  Fami- 
liar enough  also  are  we  with  the  effects  of  full 
and  sparing,  of  simple  and  mixed  dietetics, 
and  with  the  fact  that  between  certain  well- 
known  bounds  lie  the.  salutary  quantities  and 
qualities.  From  all  which  it  appears  suffici- 
ently evident,  that  we  cannot  conceive  any 
difference  iu  the  amount  or  properties  of  the 
known  stimuli  of  life,  that  would  be  more 


favourable  to  the  growth  of  man,  than  those 
which  are  to  be  found  in  the  range  of  the  known 
variations,  whether  natural  or  artificial.  From 
the  beginning  there  must  have  been  established 
a  direct  relation  between  the  organization  of 
the  body  and  the  outward  elements;  the  latter 
are  nothing  but  stimulants  adapted  to  co-exist- 
ing susceptibilities,  or  to  put  it  more  closely, 
man  is  not  made  by,  but  for  or  with,  the  sur- 
rounding agents ;  his  lungs  are  fashioned  in  cor- 
respondence to  the  atmosphere  which  he  breathes, 
his  digestive  organs  to  the  food  that  is  spread 
so  plenteously  before  him,  and  his  nervous 
system  to  the  subtle  imponderable  agents  that 
play  about  him ;  consequently  as  his  organs 
only  act  in  concert  with,  and  do  not  result  from 
the  media  of  his  existence,  a  development  be- 
yond that  which  he  is  known  to  acquire  must 
proceed  quite  as  much  from  the  former  as  from 
the  latter;  and  the  supposition,  the  value  of 
which  we  have  been  endeavouring  to  estimate, 
thus  falls  to  the  ground.  If  man  could  become 
a.  larger,  more  powerful,  or  more  sagacious 
animal  than  he  now  is,  he  must  not  only  live  in 
different  media,  but  must  possess  a  different 
constitution ;  in  other  words,  the  characters 
that  distinguish  him  as  a  species  must  be 
altered.  The  question,  then,  that  offered  itself 
remains  to  our  apprehension  unsolved  by  either 
of  the  hypotheses.  The  limitation  of  man's 
development  is  like  the  definite  period  of  his 
duration,  and  a  hundred  other  circumstances 
connected  with  his  existence,  an  ultimate  fact ; 
no  event  that  we  are  able  to  discover  intervenes 
between  its  production  and  the  will  of  the 
Deity. 

Maturity,  though  varying  with  every  indi- 
vidual, may  be  said  to  take  place  somewhere 
between  the  ages  of  twenty-five  and  thirty.  It 
is  a  general  opinion  that  it  is  a  stationary  con- 
dition ;  that  when  such  changes  have  taken 
place  in  the  frame,  as  render  the  human  being 
capable  of  undertaking  the  various  duties  and 
occupations  to  which  adults  alone  are  adequate, 
there  are  no  further  alterations  till  the  period  of 
declining  age  ;  that,  in  short,  growth  has  entirely 
ceased.  But  this  idea  is  not  strictly  correct, 
for  there  is  in  all  probability  no  period  when 
the  system  is  absolutely  stationary;  it  must 
either  be  advancing  to  or  receding  from  the 
state  of  perfection.  This  is  of  course  more 
obvious  when  we  know  that  augmentation  of 
bulk  is  only  a  part  of  that  process  which  per- 
fects the  organization.  (See  NUTRITION.)  It 
is  true  that  at  the  adult  age  the  determinate 
height  and  figure,  the  settled  features,  the 
marked  mental  and  moral  character,  naturally 
give  rise  to  the  idea  that  a  fixed  point  has  been 
attained ;  but  a  little  inquiry  soon  teaches  us 
that  the  individual  is  still  the  subject  of  some 
progressive  changes.  It  is  the  stature  only  that 
is  stationary,  for  this  depends  on  the  skeleton, 
which  ceases  to  lengthen  before  the  period  we 
speak  of.  But  the  capability  of  powerful  and 
prolonged  muscular  exertions  increases  for  some 
years ;  there  must  consequently  be  a  change  in 
the  muscular  tissue.  The  intellectual  faculties 
have  not  attained  their  maximum,  although  we 


AGE. 


77 


do  not  hesitate  to  consider  them  mature;  we     structures  are  supplied  with   nmt.nals  by  the 

Mb     fluids  in  those  structures,  it  is  rvidn.t  tint  th.-y 
the      must  at  any  time  be  incensed,  dimmish,-.!,  at 


must  therefore  infer  that  there  is  a  correspond- 
ing organic  development  of  some  kind  in 
cerebral  substance.  Maturity  then  would,  ac- 
cording to  this  view,  require  to  be  dated  at  a 
period  much  later  than  that  which  is  usually 
assigned  to  it.  It  is  enough,  however,  without 
referring  further,  to  know  that  although  at  the 
adult  period  the  organs  of  animal  life  are  so 
developed,  that  we  cannot  consider  them  im- 
perfect instruments,  they  are  even  afterwards 
the  subjects  of  a  perftctionnement.  What  is 
commonly  meant  then  by  maturity,  is  in  strict- 
ness that  period  of  human  existence,  during 
which  the  processes  of  growth  and  decline  are 
passing  into  each  other  by  such  slow  degrees 
as  to  be  imperceptible. 

In  this  important  era  of  the  life  of  man, 
more  important  even  than  the  season  of  adole- 
scence, we  must  leave  him  in  the  full  posses- 
sion of  all  the  faculties  and  energies  which  his 
Maker  has  allotted  him,  fulfilling  his  destiny  of 
good  and  evil,  encountering  and  triumphing 
over  peril,  toil,  and  pain,  scaling  the  rough 
steep  of  ambition,  threading  the  dark  intricate 
paths  of  gain,  labouring  for  the  happiness  or 
misery  of  his  fellow-creatures,  supported  all 
the  while  by  the  consciousness  of  a  strength 
that  seems  never  to  fail  him,  of  resources  never 
to  be  exhausted ;  we  must  allow  a  few  years  to 
roll  by,  and  then  return  to  him,  when  weary, 
wayworn,  and  broken  with  the  storms  of  life, 
he  has  discovered  that  there  are  limits  to  his 
powers  of  action  and  endurance  ;  that  of  the 
objects  which  he  proposed  as  the  ends  of  his 
labours,  while  a  few  have  been  accomplished, 
the  majority  are  either  vain  or  unattainable; 
and  that  a  race  fresh  in  vigour,  and  high  in 
hope,  the  images  of  his  former  self,  are  over- 
taking and  thrusting  him  away  from  the  scenes 
of  his  exertions.  What  are  the  revolutions 
that  have  transpired  in  his  system  ? 

The  formative  organs  of  all  the  tissues  of 
the  body  are  in  reality  the  tissues  themselves ; 
whether  it  be  a  muscle,  or  a  gland,  or  the  coat 
of  a  vessel,  the  parts  which  essentially  produce 
its  growth  are  nothing  more  or  less  than  its 
own  constituent  molecules,  the  mutual  attrac- 
tions of  which  in  deposition  and  absorption 
constitute  assimilation ;  for  there  is  no  proof 
that  vessels  are  used  for  any  other  purpose 
than  that  of  conveying  the  nutrient  fluids  to 
and  from  the  places,  where  the  ultimate  mole- 
cules arrange  themselves  in  the  form  of  tissue. 
The  altered  qualities,  then,  which  are  presented 
by  the  tissues,  in  whatever  organs,  in  the  de- 
cline of  life,  must  depend  immediately  upon 
alterations  in  their  own  molecular  motions 
and  affinities.  The  nature  of  these  alterations 
will  of  course  correspond  to  the  nature  of  each 
tissue ;  and  unless  we  mistake,  they  will  all 
be  found  to  agree  in  one  character,  viz.  a  sim- 
pler composition,  a  lower  kind  of  organization 
than  they  formerly  possessed.  But  the  discussion 
of  this  point  will  be  more  conveniently  deferred 
till  we  shall  have  briefly  recited  the  principal 
changes  in  the  more  important  parts  of  the 
body. 

As  the   nutritive  secretions  of  the  various 


otherwise  modified  by  changes  ...  thr  quantity 
and  properties  of  these  fluids.  Jt  ii  therefore 
a  natural  commencement  of  the  subject  to  begin 
with  the  circulating  system. 

Nothing  is  more  obvious  in  the  condition  of 
the  aged  as  contrasted  with  the  young  than  tin- 
different  ratio  between  the  fluids'and  ih(-  solids, 
the  former  being  remarkably  deficient.  There 
is  not  only  a  notable  diminution  in  the  quantity 
of  oleaginous  or  serous  secretions,  which  ;„•'»• 
generally  contained  in  the  cellular  parts  «,f  tin- 
body,  but  it  is  manifest  that  the  tissues  are  per- 
meated by  a  much  smaller  proportion  of  blood. 
This  fluid  moreover  is  very  different  in  quality 
from  what  it  was  in  earlier  life;  it  is  I, 
rial,  its  colour  has  not  the  same  bright  red  it 
once  presented,  it  has  a  large  proportion  of 
serum,  and  its  coagulum  is  less  firm  in  con- 
sistence.* Correspondently  with  the  defi- 
ciency of  fluids,  many  parts  which  once 
contained  them  are  shrunk  or  obliterated.  The 
capillary  system  becomes  infinitely  less  ex- 
tended than  it  once  was  ;  many  of  the  extreme 
branches  of  the  arteries  themselves  are  no  longer 
to  be  penetrated,  and  those  which  remain  per- 
vious, are  far  less  distensible  than  formerly. 
There  is  indeed  a  remarkable  change  in  the 
coats  of  these  vessels ;  they  are  not  only  con- 
tracted in  diameter,  but  are  become  denser  and 
more  rigid  in  texture.  In  this  respect  they  dif- 
fer from  the  veins,  which  in  old  age  are  more 
dilatable  than  in  youth,  and  consequently  con- 
tain a  larger  quantity  of  blood.  The  final 
cause  of  this  is  evident ;  in  youth  the  arteries 
must  convey  a  relatively  larger  quantity  to  sup- 
ply the  increasing  structures ;  in  the  decline  of 
life,  when  the  latter  are  decreasing,  there  can  no 
longer  be  any  need  for  the  same  supply; 
the  permission,  however,  of  an  accumulation  in 
the  veins,  where  it  is  less  likely  to  be  productive 
of  injury,  appears  to  be  an  accommodation  to 
the  diminution  of  the  circulating  powers. 

If  we  trace  the  arteries  from  their  extremities 
back  to  the  heart,  we  shall  find  their  calibres 
every  where  diminished,  their  coats  less  elastic, 
less  capable  of  adapting  themselves  to  the 
varying  quantity  of  their  contents,  in  some 
places  resembling  the  texture  of  ligament,  in 
some  that  of  cartilage,  and  in  others  studded 
with  deposits  of  osseous  matter.  The  heart 
itself  presents  marks  of  degeneration  no  less 
decided  ;  its  cavities  are  shrunk,  its  fibres  pale, 
and  but  feebly  contractile,  and  fat  will  some- 
times seem  to  take  .the  place  of  the  muscular 
substance.  Frequently,  also,  the  coronary  arte- 
ries are  found  ossified,  and  the  same  alteration 
is  not  uncommon  in  the  valves. 

All  these  facts  account  for  the  slow,  languid, 
staggering  circulation  characteristic  of  advanced 
life  ;  there  is  less  blood  to  be  transmitted  to  the 
various  organs,  and  that  which  is  sent  is  pro- 
pelled with  a  degree  of  feebleness  that  shows 
how  little  energy  is  required  in  its  motion,  when 

*  De  Blainville  is  of  opinion  that  these  change* 
arc  exaggerated.  Cours  Ue  Physiologic,  i.  26'2. 


78 


AGE. 


so  few  nutritive  actions  are  transpiring.  We 
have  spoken  of  the  altered  character  of  the 
blood,  of  its  being  less  arterial  and  of  a  darker 
tint :  this  change  is  explained  by  the  alteration 
in  the  respiratory  system.  The  lungs  are  be- 
come lighter,  the  cells  being  relatively  much 
larger,'*  and  the  parenchyma,  which  consists 
principally  of  bloodvessels,  being  greatly  di- 
minished. This  alone  would  not  explain  why 
the  blood  is  imperfectly  arterialized,  because, 
although  the  respiratory  surface  is  diminished, 
less  of  that  fluid  enters  the  organ.  But  the 
bronchial  membrane  is  always  in  a  more  or  less 
unhealthy  condition,  being  covered  with  a  thick 
and  copious  secretion,  that  constitutes  the  "  old 
man's  catarrh,"  and  prevents  a  due  intercourse 
between  the  air  and  the  blood.  Besides  this 
circumstance,  the  expansion  of  the  chest  is  less 
perfect  in  consequence  of  the  diminished  elas- 
ticity of  the  parietes  of  the  chest  produced  by 
the  ossification  of  the  cartilages  and  other 
causes :  the  muscles  also  participate  with  less 
energy  in  the  respiratory  movements.  Every 
thing  in  the  history  of  advanced  life  indicates 
the  diminution  in  the  vigour  of  the  circulation 
and  respiration.  The  apathy  and  languor  of 
mind,  the  deficiency  of  many  secretions,  and 
the  general  decrease  of  animal  heat,  but  par- 
ticularly in  the  parts  most  distant  from  the  heart, 
are  all  more  or  less  intimately  connected  with 
the  failure  of  these  vital  actions. 

On  turning  to  the  digestive  apparatus  we 
have  abundant  marks  of  deterioration.  The 
teeth  fall  out,  the  alveolar  processes  are  ab- 
sorbed, and  the  gums  become  hardened.  In 
addition  to  these  there  is  a  change  in  the  mus- 
cularity of  the  stomach ;  it  has  become  weak, 
attenuated,  and  less  contractile.  The  same  is 
true  of  the  intestines.  The  lacteal  vessels  are 
much  fewer  in  number,  and  scarcely  any  lym- 
phatic glands  are  to  be  met  with.  Every  thing 
intimates  that  the  food  is  less  perfectly  acted 
upon,  and  that  consequently  less  chyle  is  ex- 
tracted, and  transmitted  to  the  circulation. 

Since,  then,  in  these  several  systems,  we  find 
marks  of  diminution,  impairment,  depravation, 
it  is  not  wonderful  that  nutrition,  which  is  per- 
formed by  means  of  the  materials  supplied  by 
those  systems,  partakes  of  the  same  characters. 
But  as  nutritive  changes  must  have  occurred  in 
the  various  deteriorated  parts  just  spoken  of, 
it  would  be  incorrect  to  say  that  alterations  of 
tissue  depend  solely  on  the  alterations  of  these 


*  M.  Andral,  in  his  description  of  the  atrophy  of 
the  lung  which  occurs  in  aged  persons,  says,  "  In 
some  cases  the  walls  of  the  cells  disappear  alto- 
gether, and  we  only  find  in  their  stead  some  delicate 
laminae  or  filaments,  traversing  in  different  directions 
cavities  of  various  sizes.  In  the  parts  of  the  lung 
where  these  alterations  exist,  there  are  no  longer  to 
be  found  either  bronchial  ramifications,  or  vesicles 
properly  so  called,  but  merely  cells  of  greater  or  less 
diameter,  divided  into  several  compartments  by  im- 
perfect septa  or  irregular  laminae.  Many  of  these 
cells  bear  a  perfect  resemblance  to  the  lung  of  the 
tortoise  tribe,  and  they  all  approach  to  it  more  or 
less  as  to  a  type  of  organisation,  towards  which  the 
human  being  in  this  case  seems  to  descend.  Pathol. 
Anat.  v.  ii.  p.  528,  translated  by  Drs.  Townsend 
and  West. 


systems,  though  they  are  promoted  by  them  ; 
they  must,  in  fact,  have  assisted  each  other. 
The  altered  tissues  could  not  have  been  easily 
thus  changed,  without  a  defect  in  the  quantity 
or  quality  of  the  matters  out  of  which  they  are 
formed  ;  nor  could  the  latter  defects  have  easily 
occurred  without  some  alteration  in  the  texture 
of  the  parts  employed  in  conveying  and  ela- 
borating the  nutrient  fluid.  It  is  an  old  saying, 
that  the  functions  of  the  body  form  a  circle  :  if 
this  be  true  of  their  healthy  condition,  it  is  not 
less  so  of  their  diseases  and  decline. 

The  organs  and  tissues  subservient  to  the 
organic  life  having  undergone  vitiation  and 
diminution,  we  may  expect  to  find  equal  or 
even  greater  decay  in  the  parts  which  are  alto- 
gether dependent  upon  them,  or  the  organs 
of  the  supplemental  life.  These  indeed,  as 
they  are  the  last  to  be  developed,  are  some  of 
the  first  to  present  marks  of  decline,  and  evi- 
dently for  the  same  reason,  viz.  because  they 
are  appended  to  and  generated  by  the  other 
parts  of  the  system,  and  also  are  more  open  to 
our  observation.  The  body  is  indeed,  in  this 
respect  as  in  many  others,  not  unlike  a  poli- 
tical community ;  no  great  change  can  occur  in 
its  internal  arrangements,  such  as  a  failure 
or  derangement  of  its  energies  and  resources, 
without  a  manifestation  of  this  weakness  or 
disorder  in  its  foreign  relations. 

Let  us  proceed,  then,  to  examine  the  ravages 
which  are  wrought  by  the  hand  of  time  on  the 
organs  of  locomotion  and  sensation,  in  the 
same  order  in  which  we  have  traced  the  deve- 
lopments and  amplifications,  once  lavished  by 
the  self-same  agent. 

And  first  of  the  bones.  The  process  of 
development  in  these  parts  consisted  of  a 
certain  adjustment  of  the  animal  to  the  earthy 
matter,  in  order  to  give  the  requisite  firmness, 
toughness,  and  solidity.  As  life  advances,  the 
phosphate  and  carbonate  of  lime  are  found  to 
exceed  the  proportion  of  the  cartilage  and 
gelatine.  The  general  conformation  of  the 
bones  is  less  regular ;  they  look  shrunken  and 
worn.  When  handled  they  feel  lighter,  not- 
withstanding the  osseous  substance  is  in  excess; 
a  fact,  which  results  from  the  diminished 
quantity  of  the  fluids,  and  one  or  two  other 
circumstances  to  be  mentioned  presently.  The 
processes  and  ridges,  once  so  eminent  and  dis- 
tinct, are  comparatively  effaced ;  this  alteration 
accords  with  the  wasting  and  diminished  exer- 
cise of  the  muscles  that  were  attached  to  these 
eminences.  On  looking  for  the  lines  and  spaces, 
which  are  occupied  in  early  life  by  cartilages  or 
membranes,  and  which  are  visible  even  in 
manhood,  we  now  find  every  trace  of  them 
vanished.  Thus,  the  divisions  between  the 
epiphyses  and  shafts  of  the  long  bones,  the 
line  of  union  between  the  bones  of  the  pelvis, 
and,  in  a  still  more  marked  degree,  the  sutural 
outlines  of  the  bones  of  the  head,  are  no  longer 
perceptible.  They  are  all  filled  up  with  bony 
deposit,  and  the  pelvis  and  cranium  form 
single  bones ;  even  the  foramina  by  which  the 
nutrient  arteries  entered  the  tissue  are  con- 
tracted or  obliterated.  The  cellular  structure 
between  the  tables  of  the  cranium  is  removed  ; 


AGE. 


and  the  outer  plate  has  approximated  and 
indeed  become  identified  with  the  inner; 
hence  we  see  more  depressions  on  the  surface 
of  an  aged  skull. 

On  inspecting  the  internal  structure  of  these 
organs,  we  find  the  cavities  that  contain  the 
marrow  much  more  extensive  than  formerly, 
and  the  medullary  tissue  reduced  to  a  con- 
sistence scarcely  exceeding  that  of  oil.  The 
cells  also  of  the  short  bones  and  of  the  ex- 
tremities are  more  expanded,  and  the  laminae 
which  form  them  are  very  much  attenuated. 

The  deficiency  of  animal  matter  renders  the 
bones  of  the  aged  fragile ;  they  are  broken  by 
the  most  trivial  accidents.  It  is  also  the  cause 
of  their  slowness  to  unite;  for  the  activity  of 
assimilative,  and  consequently  of  reparative 
processes,  is  dependent  on  the  vascularity  and 
fluidity  of  a  tissue.  The  lightness,  however, 
of  these  organs  produced  by  the  same  cause  is 
beneficial,  or  at  all  events  in  harmony  with  the 
state  of  the  muscular  system. 

If  we  next  turn  our  attention  to  the  ar- 
ticulations, we  shall  find  that  similar  pro- 
cesses of  disqualification  for  former  functions 
have  ensued.  The  spinal  column,  which 
once  adapted  itself  with  such  ease  and  flexi- 
bility to  the  motions  and  curves  of  the 
body,  has  become  almost  as  rigid  as  a  single 
bone  by  the  drying  up  of  the  intervertebral 
cartilages,  and  sometimes  by  the  encroach- 
ments of  ossification.*  Scarcely  any  traces  of 
cartilages  between  the  ribs  and  the  sternum 
can  now  be  found ;  one  of  the  causes  to  which 
we  alluded  above,  in  connection  with  dimi- 
nished respiration.  The  same  deficiency  of 
cartilage  is  observable  in  the  bones  of  the  wrist 
and  of  the  tarsus.  A  change,  the  opposite  of 
mobility,  may  also  be  detected  in  the  liga- 
ments which  embrace  the  joints;  they  are 
dense,  dry,  and  inelastic.  The  gelatine  which 
enters  so  largely  into  their  composition  has 
become  altered  in  its  chemical  properties ; 
it  is  less  easily  soluble  in  water,  and  has  all 
the  characters  of  glue  rather  than  of  jelly. 
Ill-adapted  as  this  state  of  the  articulations  is 
to  the  purposes  of  motion,  it  is,  we  think,  not 
altogether  difficult  to  discern  its  appropriateness 
to  the  human  being  at  this  advanced  period. 
Were  the  joints  supple  and  flexible,  while  the 
muscles  have  so  little  power,  how  much 
greater  would  be  the  risks  of  accidents  to  the 
aged  man  in  the  slight  motions  which  he 
achieves.  In  order  to  preserve  their  frames 
from  falling,  those  whose  joints  move  easily 
upon  each  other  are  compelled  to  exercise  those 

'  *'  Cependant  il  est  rare  que  les  fibro-cartilages 
s'ossifient  chez  les  snjets  avances  en  age.  A  la 
verite  on  voit  souvent  les  vertebres  se  reunir  avec 
les  autres  au  moyen  d'une  substance  osseuse,  mais 
cette  souture  depend  bien  plus  rarement  de  1'ossi- 
fication  des  fibro-cartilages  que  de  la  formation  de 
lames  osseuses  a  la  circonierence  des  deux  faces 
par  lesquelles  se  regardent  les  coups  des  vertebres. 
Cependant  j'ai  observe  quelquefois  aussi  I'ossifica- 
tion  des  fibro-cartilages  intervertebraux,  et  j'ai 
trouve  alors,  en  sciant  longitudinalement  la  colonne 
epiniere,  que  plusieurs  vertebres  etaient  soudees 
ensemble,  et  confondues  en  une  seule  masse." — 
Meckel,  Manuel  d'Anat.  t.  i.  p.  364. 


muscles  which  keep  the  limbs  in  the  rvm.isite 
degrees  of  extension  ami  stability,  durin -•  cer- 
tain attitudes  and   motions;    but  tins  end 
accomplished   in  the  feeble  old  subject  by  tin- 
very  stiffness  of  his  articulations. 

The  muscles  are  subject  to  dian^o  no  less 
decided  than  those  in  the  organs  jusl  ,, 
tioned.  They  are  pale,  flabby,  atrophied,  and 
indisposed  to  contract  on  the  application  of 
stimuli ;  but  the  fibre  itself  is  tough  and  not 
easily  torn,  and  the  true  muscular  suhst .,: 
seems  to  have  given  way  in  some  places  to  a 
sort  of  dense  cellular  membrane,  or  a  yellow- 
ish degeneration  of  tissue  particularly  de- 
scribed by  Bichat.  Their  tendons  are  often 
studded  with  calcareous  matter,  and  the  sheaths 
in  which  they  play  are  rigid  and  unmoistened 
with  synovia.  They  obey  the  stimulus  of  the 
will  tardily  and  irregularly;  the  uncertain 
tremulous  movements,  the  tottering  gait,  the 
stooping  posture,  the  unsteady  grasp  of  the 
aged,  are  familiar  to  every  one. 

The  organ  of  voice  comes  next  to  be  con- 
sidered. The  larynx,  once  composed  of  seve- 
ral cartilages  that  moved  freely  on  each  other, 
is  now  a  cavity  capable  of  much  less  variation 
in  its  dimensions,  owing  to  the  rigidity  of  its 
parietes;  the  extent  of  the  cavity  gives  in  early 
old  age  that  depth  of  tone,  which  by  its  gravity 
and  solemnity  excites  our  homage.  In  more 
advanced  age,  however,  the  tone  becomes 
hoarse,  shrill,  and  piping;  this  in  all  pro- 
bability is  produced  by  the  contraction  and 
stiffness  of  the  rima  glottidis,  but  still  more 
by  the  want  of  vigour  in  the  muscles  of  the 
mouth  and  throat.  The  incapability  of  ma- 
naging the  tone,  and  the  tremulous  articu- 
lation, are  also  results  of  changes  in  the  muscles 
of  the  larynx,  pharynx,  and  tongue,  similar  to 
those  which  transpire  in  other  parts  of  the 
muscular  system.  Many  senile  impediments 
of  speech  are  also  produced  by  the  loss  of 
teeth,  by  the  falling  in  of  the  cheeks,  and  by 
the  disproportion  of  the  lips  to  the  space  which 
they  occupy. 

In  our  investigation  of  the  signs  of  decay  in 
the  parts  that  are  subservient  to  sensation 
and  thought,  we  shall  be  met  by  the  same 
difficulties  which  formerly  opposed  our  way, 
when  inquiring  into  the  phenomena  of  their 
development.  We  traced  the  progress  of  the 
nervous  substance  both  in  the  nerves  and  in 
the  cerebro  -  spinal  centre  from  the  almost 
pulpy  state  recognized  in  the  infant,  to  its  firm 
consistence  in  the  adult.  If  we  now  inves- 
tigate the  anatomical  quality  presented  by  the 
tissue  in  advanced  life,  we  shall  find  that  it 
has  shared  the  alteration  of  nearly  all  the  other 
tissues, — that  in  short  it  has  increased  in  density. 
This  fact  viewed  in  connection  with  another, 
namely,  that  ramollissement  and  induration 
produce  very  nearly  the  same  lesion  of  func- 
tion, will  account  for  the  failure  in  the  sensific 
powers  of  old  age.  Besides  this  alteration  in 
the  substance  of  the  nerves,  they  are  found  to 
be  diminished  in  diameter;  their  neurilemmes 
are  become,  like  other  membranous  parts,  much 
harder  and  stronger.  Moreover,  Bichat  has 
remarked  that  the  nervous  tissue  of  old  ani- 


80 


AGE. 


mals  is  much  less  easily  affected  by  reagents 
than  that  of  younger  ones ;  so  that  there  would 
appear  to  be  an  alteration  in  the  chemical 
composition  as  well  as  in  the  mechanical  con- 
sistence. 

That  which  has  been  said  of  the  matter  of 
the  nerves  is  also  true  of  the  brain.  The 
whole  bulk  is  diminished  arid  the  density 
greater  than  in  earlier  years.  Some,  however, 
assert  that  it  is  even  softer  than  in  manhood. 
M.  Blandin  makes  a  remark  of  this  kind, 
in  commenting  upon  Bichat's  statement  of  a 
greater  hardness  in  the  tissue,  and  says  that 
it  might  be  expected  a  priori,  since  there  is  so 
strong  a  correspondence  between  the  two  ex- 
tremes of  life.  There  is  reason,  however,  to 
think  that  this  remark,  if  true  at  all,  applies 
only  to  the  cerebral  organ  of  persons  very  far 
advanced ;  and  it  is  not  improbable  that  dis- 
eased softening  has  in  other  cases  been  mis- 
taken for  the  natural  effect  of  age.  The  mem- 
branes investing  the  brain  like  the  neurilemmes 
(for  they  belong  to  the  same  system)  are  also 
thicker  and  more  resistent.  The  vascularity 
of  the  organ  is  greatly  diminished ;  on  a  di- 
vided surface  no  red  dots  are  visible  as  at 
periods  less  advanced. 

The  alterations  in  the  mechanism  of  the 
senses  must  next  be  considered.  The  skin, 
which  is  the  medium  between  the  nerves  of 
tact,  and  external  agents,  undergoes  great 
changes  in  the  progress  of  life.  It  becomes 
drier,  harder,  less  flexible,  and  at  the  same 
time  looser,  in  consequence  of  the  absorp- 
tion of  the  adipose  substance.  By  the  latter 
qualities  the  function  of  the  skin  is  more 
evidently  impaired,  in  that  modification  of  it 
more  expressly  denominated  touch,  or  the 
sense  of  tact  united  with  certain  muscular 
feelings  in  the  fingers  and  hands.  By  the 
looseness  of  the  integuments,  the  slowness  and 
weakness  of  the  muscles,  the  stiffness  of  the 
digital  joints,  and  that  dulness  of  sensation 
which  exists  in  this  as  in  every  other  part  of  the 
system  more  or  less,  the  hand  is  notably 
deteriorated  in  old  age. 

In  the  olfactory  apparatus  we  find  that, 
although  the  cavities  and  sinuses,  through 
which  the  Schneiderian  membrane  is  ex- 
tended, are  rather  increased  than  diminished 
in  size,  the  membrane  itself  is  attenuated  and 
less  pulpy.  The  nerve  also  is  mentioned  by 
Rulher*  to  be  evidently  contracted  and  wasted. 
The  sense  of  taste  so  closely  connected  with 
that  just  spoken  of  survives  to  the  extremes!  limit 
of  existence ;  the  final  cause  of  which  is  evi- 
dent. It  is  too  intimately  connected  with  one 
of  the  processes  of  organic  life  to  be  easily 
dispensed  with,  although  one  of  the  functions 
of  the  superadded  life.  It  is,  however,  feebler 
than  at  periods  less  advanced,  and  requires 
the  excitement  of  more  piquant  aliment ;  this 
is  partly  owing  to  the  diminished  sensibility 
of  the  gustatory  nerve  itself,  and  partly  to  the 
diminution  of  the  sense  of  smell,  on  the  per- 
fection of  which  depends  our  appreciation  of 
the  more  delicate  species  of  sapidity.  The 

*  Diet,  de  Med.  art.  Aye. 


surface  of  the  tongue  is  more  rugose  than  in 
younger  subjects,  and  there  is  generally  a  de- 
ficiency of  moisture,  which  is  an  additional 
cause  of  diminished  sensation. 

The  ear,  both  in  its  external  appendages 
and  in  its  internal  structure,  presents  certain 
conditions  which  very  well  account  for  the 
frequency  of  deafness  among  the  aged.  It  is 
true  the  cartilages  become  harder,  more  elastic, 
and  therefore  more  vibratory,  but  the  internal 
surface  of  the  meatus  is  often  thickened,  and 
obstructed  by  a  dense  cerumen.  The  mem- 
brana  tympani  is  more  rigid  and  therefore  less 
capable  of  varying  with  the  degree  of  the  vibra- 
tions. In  the  internal  cavity,  although  the 
mastoid  cells  are  enlarged  as  life  advances, 
the  deficiency  of  the  liquor  cotunnii  in  the 
vestibule,  the  cochlea,  and  the  semicircular 
canals,  must  greatly  interfere  with  the  produc- 
tion of  hearing.  In  addition  to  all  these  cir- 
cumstances there  is  probably  an  idiopathic 
insensibility  of  the  nerve. 

The  modifications  of  the  organ  of  vision  are 
familiar  to  all  who  have  paid  even  the  most 
superficial  attention  to  the  science  of  optics. 
The  cornea  is  less  transparent  and  less  convex, 
partly  from  the  diminution  of  the  aqueous 
humour,  and  partly  from  the  condensation  of 
its  texture.  The  latter  change  is  more  marked 
at  the  circumference,  where  a  nebulosity  is 
often  formed,  which  has  gotten  the  name  of 
gerontotoxon,  or  arcus  senilis.  The  pigmentum 
diminishes,  and  the  iris  grows  paler  in  con- 
formity with  the  altered  colour  of  the  hair. 
The  crystalline  lens  is  denser,  less  transparent, 
and  often  acquires  a  yellow  tint ;  the  vitreous 
hufnour  likewise  suffers  a  decrease.  The  retina 
is  considerably  attenuated,  but  has  increased  in 
firmness.  The  punctum  luteum  is  paler,  and 
not  unfrequently  altogether  effaced ;  a  change 
which,  in  the  opinion  of  Meckel,*  bears  a  direct 
ratio  to  the  diminution  of  the  transparency  of 
the  cornea.  These  several  .alterations  are  ne- 
cessarily followed  by  two  results — diminished 
refraction  of  the  rays  of  light,  and  torpor  of  the 
nervous  function,  both  of  which  prod  uce  pres- 
byopia. That  long  sight  bears  a  relation  with 
nervous  as  well  as  more  mechanical  causes  is, 
we  think,  attested  by  the  fact  that  this  kind  of 
vision  is  modified  by  temporary  excitement  of 
the  brain,  as  in  phrenitis.f 

If  we  now  take  a  retrospect  of  the  revolu- 
tions which  have  occurred  in  the  several  struc- 
tures enumerated,  and  endeavour  to  arrange 
them  under  specific  heads,  it  will  be  found 
that  diminution  of  bulk,  deficiency  of  fluid, 
and  condensation  of  substance,  comprehend 
them  all  or  nearly  all.  The  attenuatjon  has 
been  generally  ascribed  to  a  preponderance  of 
absorption  over  deposition,  or  a  reverse  of  that 
condition  in  which  incremental  growth  consists. 
But  we  cannot  enter  upon  the  question  here, 
and  must  refer  to  the  article  NUTRITION,  con- 
tenting ourselves  with  the  remark  that  it  seems 
a  superfluous  multiplication  of  causes  to  sup- 

*  Op.  cit.  t.  iii.  p.  261. 

t  See  Abercrombie  on  Diseases  of  the  Brain. 


AGE. 


pose  that  absorption  increases,  when  the  cessa- 
tion or  diminution  of  deposition  fully  explains 
the  fact,  provided  the  absorption  is  only  main- 
tained in  its  usual  ratio. 

Concerning  the  lessened  quantity  of  fluid  we 
have  already  made  some  remarks,  and  hinted 
at  its  relation  with  impaired  digestion  and 
slackened  circulation.  Here  it  is  sufficient  to 
observe  that  the  fact  is  a  sign  of  diminished 
vitality,  by  which  we  mean  merely  a  diminu- 
tion of  vital  actions,  especially  of  those  of  nu- 
trition. The  abundance  of  fluid  in  the  young 
succulent  body  is  adapted  to  the  constant  accu- 
mulation of  new  particles,  and  to  the  increasing 
complexity  of  the  organization  of  the  tissues, 
as  well  as  to  the  reparation  of  waste,  or  to  the 
counteraction  of  decomposition; — by  the  still 
abundant  though  diminished  quantity  in  the 
adult  the  composition  is  maintained  and  ren- 
dered more  exquisite; — in  the  old  man  there  is 
only  enough  required  to  keep  up  that  degree  of 
renovation,  which  is  necessary  to  the  integrity 
of  the  structure,  and  even  this  action  is  less 
than  in  former  periods,  because  the  organiza- 
tion, from  its  chemical  nature,  is  less  prone  to 
decomposition.  This  brings  us  to  the  con- 
sideration of  the  third  general  fact,  or  the 
condensation  of  tissue,  which  will  require 
more  particular  notice,  because  great  impor- 
tance has  been  assigned  to  it  by  some  writers. 
The  condensation  is  a  result  of  the  deficient 
humidity  just  spoken  of;  but  this  is  not  all, 
otherwise  the  condensation  would  be  merely 
that  of  dryness ;  the  tissue  itself  is  of  firmer 
materials.  Thus  membrane  becomes  ligament, 
ligament  cartilage,  cartilage  bone,  and  bone 
increases  in  its  earthy  proportions.  This  har- 
dening of  the  whole  body  is  spoken  of  by 
many  writers  as  the  cause  of  decay,  and  ulti- 
mately of  death,  by  the  gradual  closure  of  all 
the  small  vessels,  and  the  obstruction  to  vital 
motions ;  while  the  methods  of  averting  old 
age,  proposed  by  the  same  authors,  turned 
chiefly  upon  an  artificial  supply  of  moisture  to 
the  body.  Galen  constantly  alludes  to  this 
condition  when  treating  of  old  age,  and  the 
means  of  resisting  its  tendencies.*  Lord  Bacon, 
in  his  curious  and  highly  interesting  treatise, 
entitled  Historia  Vitae  et  Mortis,  has  much  to 
say  upon  desiccation  and  the  methods  of  pre- 
venting it,  suqh  as  bathing  and  inunction. 
The  fable  of  the  restitution  of  old  ^sop  by 
the  cauldron  of  Medea,  he  considers  typical 
of  the  utility  of  the  warm  bath  in  softening 
the  substance  of  the  body.  So  much  stress 
does  Haller  lay  on  the  effect  of  the  universal 
tendency  to  induration,  that  he  tells  us  that  one 
of  the  reasons  why  fishes  are  so  long-lived  is 
because  their  bones  are  never  hardened  to  the 
same  degree  as  in  the  higher  animals — "  Inter 
animalia  aves  longaeviores  sunt,  longaevissimi 
pisces,  quibus  cor  minimum,  et  lentissimum 
incrementum,  et  ossa  nunquam  indurantur." 
Primae  Lineae,  §  972.  There  is,  however,  we 
think,  but  little  foundation  for  the  supposition 
that  induration  stands  in  the  relation  of  cause 

*  See  his  treatises  De  Sanitate  Tuenda,  and  De 
Marasmo. 
VOL.  I. 


to  the  general  failure  of  the  functions  of  the 
body.  It  is  rather  a  symptom  of  decline,  or 
one  of  the  phenomena  in  \\hi<  h  decline  con- 
sists, and  is  therefore  itself  the  effect  of  the 
failure  or  alteration  of  some  of  the  functions, 
more  especially  of  the  assimilative.  It  •  , 
deterioration  of  interstitial  secretion,  partly 
promoted  by  the  changes  in  circulation,  in  di- 
gestion, and  probably  in  innervation,  and  partly 
itself  contributing  to  these  changes,  but  pri- 
marily owing  its  origin,  like  the  latter,  to  the 
ultimate  law,  which  determines  that  at  a  certain 
period  decay  shall  transpire.  It  is  in  one  re- 
spect a  descent  in  the  scale  of  organization.  This 
indeed  is  indicated  by  the  paucity  of  fluids  and 
by  the  slow  nutritive  motions,  which  conditions 
are  always  sufficient  to  warrant  our  application 
of  the  terms,  diminished  vitality  or  less  vitalized 
structure;  but  the  substance  itself,  indepen- 
dently of  these  deficiencies  of  action,  belongs 
to  a  more  simple  organization.  We  examine  a 
bloodvessel,  and  instead  of  finding  its  coats  of 
that  complex  texture  which  enables  it  to  ac- 
commodate itself  by  a  property,  known  only 
in  living  bodies,  similar  but  superior  to  elasti- 
city, we  mean  tonicity,  we  observe  a  plate  of 
osseous  matter,  unyielding,  insensible,  immo- 
bile, possessing  no  other  vital  character  than 
bare  assimilation  or  molecular  growth.  We 
search  for  those  admirably  constructed  sub- 
stances which  are  interposed  between  the  ribs 
and  the  sternum,  and  by  their  elasticity  give 
extent  and  facility  to  the  respiratory  move- 
ments, and  we  discover  them  converted  into 
the  same  matter  as  the  contiguous  bones,  with 
the  coarse  property  of  cohesion,  and,  as  in  the 
former  instance,  with  nothing  but  its  growth  to 
redeem  it  from  the  character  of  mere  inorganic 
matter.  We  untangle  the  muscle,  and  instead 
of  the  irritable  fibre,  soft  in  texture  but  firm  in 
contraction,  we  find  a  torpid  substance,  scarcely 
fibrous  in  form,  firm  in  mere  physical  cohesion, 
weak  in  vital  contraction,  and  consequently  of 
a  degraded  organization.  The  processes  of 
induration  about  the  joints,  the  glands,  and 
the  integuments,  will  all,  when  examined,  be 
found  to  approximate  more  than  the  former 
conditions  of  these  parts  to  the  qualities  of  the 
inanimate  world.  Homogeneousness  of  sub- 
stance is  alone  an  indication  of  a  low  organi- 
zation, and  a  body  which  possesses  both  this 
property  and  hardness,  maybe  considered  on 
the  very  outskirts  of  the  region  of  vitality. 
Such  are  the  properties  of  osseous  deposits. 
May  we  not  here  perceive  an  analogy  with  the 
animals  of  the  inferior  classes  ?  In  many  of 
the  mollusca  how  trifling  a  degree  of  vitality 
seems  adequate  to  the  formation,  growth,  and 
reparation  of  their  calcareous  coverings  and 
appendages;  or  to  go  down  to  the  coralines, 
madrepores,  and  porifera,  we  observe  that  the 
very  lowest  structure  that  can  be  considered 
animal  is  sufficient  to  secrete  or  assimilate 
those  vast  collections  of  earthy  matter  which 
pave  the  ocean,  and  rise  into  islands,  moun- 
tains, and  mighty  continents.  In  this  har- 
dened constitution,  this  simplified  but  dege- 
nerate structure,  we  see  that  the  frame  of  man, 
in  its  natural  decay,  loses  the  characters  that 


AGE. 


once  distinguished  it  from  the  dust,  and  that 
not  less  literally  than  truly  it  has  become  more 
and  more  "  of  the  earth  earthy." 

We  have  now  traversed  as  far  and  as  mi- 
nutely as  our  space  would  allow,  the  organs 
and  tissues,  with  their  various  alterations.  It 
remains  for  us  to  inquire  whether  any  one  of 
them  may  be  considered  to  stand  in  the  rela- 
tion of  cause  to  the  others.  We  have  already 
dismissed  the  supposition,  that  rigidity  and  con- 
cretion are  productive  of  the  other  alterations, 
and  we  also  partly  entertained  the  question, 
when  treating  of  the  relations  between  assimi- 
lation, the  fluids,  and  the  organs  subservient  to 
circulation  and  digestion.  But  there  are  one  or 
two  additional  points  which  must  be  alluded  to 
in  this  place. 

The  decay  of  all  the  organs,  concerned  in 
the  life  of  relations,  has  been  shewn  to  depend 
on  a  failure  in  the  actions  which  are  necessary 
to  their  generation  and  maintenance;    these 
organs   may,  therefore,  be  dismissed  at  once 
from  our  inquiry  into  the  causation  or  priority 
of  the  processes   of  degeneration.      Yet  the 
observation  of  the  marked  declension  of  the 
function  of  the  nervous  system  throughout  the 
body,    has    led    to   the   hypothesis,  that  the 
failure  in  this  power  is  the  ultimate  fact  in  the 
history  of  our  decline,  the  fact  to  which  all  the 
others  may  be  traced.     This  view  is  suggested 
by  Dr.  Roget  in  his  justly-admired  article  on 
Age,  in  the  Cyclopaedia  of  Practical  Medicine. 
He  considers  the  general  condensation  of  tissue 
throughout  the  system,  to  be  occasioned  by  a 
diminished  force  of  circulation,  which  allows 
the  capillaries  to  collapse  and  become  obli- 
terated; the  weakened  circulation  this  distin- 
guished author  is  inclined  to  attribute  to   a 
diminution  of  nervous  power  in  the  muscular 
fibres  of  the  heart ;  whence  he  infers  that  the 
declension  of  nervous  power  bears  the  priority 
in  the  chain  of  events.     W7e  do  not  feel  pre- 
pared to  adopt  the  inference ;  for  if  we  admit 
this  failure  in  the  innervation  of  the  heart,  (and 
whether  its  fibres  are  dependent  on  nerves  for 
their  contractility,  is  still  an  unsettled  ques- 
tion,) are  we  to  pass  over  the  condition  of  the 
blood  ?     Might  we  not  say  that  the  enfeebled 
contractions  of  the  heart  are  referable  to  an 
alteration  in  the  properties  of  its  appropriate 
stimulus  ?     It  is  known  that  this  vital  fluid  has 
been  less  affected  by  respiration  than  in  former 
periods  of  our  existence ;  we  might  therefore, 
when  searching  for  the  earliest  antecedent  in 
decay,  stop  at  the  imperfect  arterialization  of 
the  blood.     But  this  would  be,  in  our  humble 
opinion,  to  pause  too   soon.      The    deficient 
oxygenation  of  the  circulating  fluid  is  sufficiently 
well  known  to  be  the  effect  of  certain  changes 
in  the  apparatus  of  respiration.     And  to  what 
do  these  changes   belong  ?     To   a  variety  of 
structural,  functional,  and  nervous  phenomena, 
which,  if  pursued,  would  lead  us  into  a  maze 
of  events,  from  which  it  would  be  impossible 
to  select  that  which  was  earliest  in  its  occur- 
rence.    Or  if  we  leave  the  respiratory  system, 
and  follow  the  blood  backward  to  the  process 
of  chylification,  and  ultimately  to  digestion,  we 
shall,  as  was  shewn  above,  be  equally  unsuc- 


cessful in  obtaining  satisfaction.     Or  finally,  if 
we  return  to  the  heart,  and  investigate  the  dimi- 
nished nervous  power,  admitting  this  diminu- 
tion to  be  alone  sufficient  for  the  debility  of 
circulation,  is  it  possible  to  stop  at  this  pheno- 
menon ?     Nervous  power  is  nothing  but  the 
function  of  nervous  substance,  and  whether  the 
latter  belongs  to  the  ganglionic  system,  or  to 
the  cerebro-spinal,  it  may  have  undergone  some 
change,  or  have   been  stimulated   differently 
from  usual.     We  know  that  the  sensibility  of 
the  nervous  system  is  most  intimately  connected 
with  the  quality  of  the  blood, and  with  the  force  of 
its  impulse  ;  so  that  if  it  be  true  that  diminished 
circulation  is  the  effect  of  diminished  innerva- 
tion, it  is  no  less  true  that  the  latter  is  also  the 
result  of  the  former.     Thus  it  appears  that  in 
this  inquiry  we  are  constantly  arguing  in   a 
circle,  and  it  can  scarcely  be  otherwise ;  the 
principal  structures  and  functions  of  the  organic 
life  commenced  simultaneously ;  they  must].de- 
cline  simultaneously :  they  assisted  one  another 
to  grow  ;  they  accelerate  each  other  in  the  way 
to  dissolution.     If,  however,  we  are  disposed 
in  some  measure  to  qualify  this  remark,  and 
still  hold  that  there  must  be  some  organic 
changes  primary  in  the  work  of  decay,  all  ana- 
logies must,  we  think,  conduct  us  to  the  simple 
processes  of  assimilation   and  secretion,  into 
which  all  the  more  complicated  functions  must 
be  ultimately  resolved ;    but  we  can   go   no 
farther,  for  we  know  not  what  determines  or 
modifies  the  play  of   those  subtle  affinities, 
motions,    and    contractions,    in    which    such 
changes  consist. 

Some  fancy  that  the  enigma  is  solved  by  the 
hypothesis  of  a  diminished  vital  power ;  but 
we  have  already  attempted  to  show  that  the 
interpretation  is  without  value,  when  applied  to 
the  cessation  of  development ;  the  same  reasons 
render  it  equally  useless  as  a  key  to  the  hiero- 
glyphics of  decay.  Not  less  vain  were  the 
endeavours  of  those  who  could  satisfy  their 
philosophy  with  such  a  subterfuge  of  ignorance 
as  was  afforded  in  the  theory  of  a  sum  of  exci- 
tability, originally  allotted  to  the  system,  and 
gradually  exhausted,  &c.;  as  if  excitability 
could  possibly  mean  any  thing  more  than  an 
expression  of  the  collective  phenomena  of  ex- 
citement, or  vital  movement.  It  is  exactly  on 
a  par  with  the  doctrine  of  decreasing  vitality.* 
Some  talk  prettily  and  poetically  of  the  vital 
flame  burning  out,  of  oil  gradually  wasting,  of 
fuel  expended,—  phrases  applicable  enough  as 
metaphors,  but  absurd  when  propounded,  as 
they  too  often  are,  as  statements  of  matters 
of  fact. 

When  philosophy  has  failed  to  discover  an- 
tecedences, she  may  still  find  a  prolific  source 
of  employment  in  the  study  of  harmonies. 
There  is  no  event  to  be  found  in  the  relation  of 
cause  to  those  organic  changes  which,  without 
the  intervention  of  accidental  agents,  ultimately 
affix  a  bound  to  the  duration  of  man's  existence. 
As  no  cause  can  be  elicited  for  the  termination 
of  development,  neither  can  we  better  explain 

*  "La  gene  de  1'influence  vitale  s'accroit  saus 
cesse." — Cabanis. 


ALBINO. 


83 


why  growth  does  not  continue  stationary,  and 
maintain  the  bodily  structures  for  a  series  of 
ages,  so  long  as  external  circumstances  remain 


the  ratio  of  subsistence.    The  time  ommi.-d 
in  attaining  maturity  bean  a  «lir«-«  -t 

to  the  period  of  existence  in  tin- 


same.     We    live  in  the  midst  of    agents     consequently,    if  life  were   proloi 

its  present  limits,  that  time  during  which  the 
offspring   of    man   is  either  helpless  or  very 


the 

that  both  supply   us  with  life  and  infest  us 

with  poison  :  for  a  time  we  resist  the  baneful 

tendencies,  and  then  gradually  succumb,  but  dependent  on  the  parents,  would  be  al- 

in  what  manner  we  are  at  present  ignorant,  ened,   and  the  accidents  of  disease  or  other 

The  prevalence  of  certain  functions  has  been  casualties  remaining  the  same,  it  is  cl- 

supposed  to  fortify  certain  animals  against  the  confusion,   distress,    and   manift.' 

outward  agents  or  inward  processes  that  would  would  accrue  to  a  rising  generation. 

otherwise  urge  them  to  dissolution.     The  in-  the  attainment  of  maturity  and  of  its  accompa- 


fluence  of  respiration  upon  nutrition  is  well 
known,  and  consequently  a  large  sum  of  respi- 
ration has  been  alleged  to  account  for  the 
longevity  of  birds ;  but  there  are  equal  or 
much  greater  instances  to  be  found  among  fishes 
and  reptiles,  the  amount  of  whose  respiration  is 
extremely  small.  In  the  one  case  the  vitality 
is  said  to  be  less  rapidly  consumed,  in  the 
other  to  be  more  abundantly  supplied  ;  expla- 
nations which  amount  to  little  more  than 
statements  of  the  same  facts  in  different  lan- 
guage. Lord  Bacon  was  of  opinion  that  birds 
owe  their  lengthened  existence  partly  to  the 
smallness  of  their  bodies,  and  partly  to  their 
being  so  well  defended  by  their  teguments 
from  the  atmosphere ;  while  he  accounted  for 
the  long  life  of  fishes  by  the  non-occurrence 
of  desiccation  in  their  aqueous  element.  There 
is  nothing  satisfactory  to  be  obtained  from 
speculations  of  this  sort.  The  most  that  we 
can  learn  is  the  variation  in  the  term  of  exist- 
ence by  the  influence  of  various  outward 
agents  and  modes  of  life.  But  whatever 
variation  may  be  discovered,  it  will  still  appear 
that  climate,  and  time,  and  custom,  and 
science  have  never  prolonged  the  date  beyond 
certain  limits.  The  study  of  these  circum- 
stances, and  the  appliances  of  art,  undoubtedly 
tend  to  enable  a  greater  number  to  attain  the 
extreme  goal,  but  can  never  give  the  power 
of  transgressing  it.  Vain,  then,  as  Boerhaave 
observes,  are  the  hopes  of  men  who  look  for 
an  agerasia! 

Although  at  present,  then,  we  cannot  trace 
the  causes  of  the  bounded  nature  of  our  existence, 
yet  it  is  not  difficult  to  discern  its  fitness  to  our 
constitution,  and  to  the  universal  frame  of 
things.  The  brevity  of  life  is  an  ancient  com- 
plaint ;  lamentations  have  been  chaunted  over 
it  time  out  of  mind  :  but  its  antiquity  does 
not  redeem  this,  any  more  than  many  other 
opinions  equally  hoary,  from  the  character  of 


nying  faculties,  it  is  not  clear  that  any  thin.? 
would  be  gained  by  the  possession  of 
for  a  longer  period  than  is  now  allowed  ;  sii  i 
know  but  too  well  that  men,  after  a  time,  lost.-  tin- 
spirit  of  enterprise  once  engendered  by  the  con- 
sciousness   of    increasing    or    lately-acquired 
powers,  and  fall  into  habits  of  action  which 
they  are  unwilling  to    abandon,  but    which 
do  not  advance  the  resources  of  the  species 
beyond  a  certain    limit.      Hence  the  advan- 
tage of  their  giving  way  to  others,  to  whom 
they  can  commit  their  knowledge,  and  who, 
by  their  unworn  energy,  will  advance  it  fur- 
ther.    "  Life  is  sufficient  for  all  its  purposes 
if  well  employed,"  was  well  observed  by  Dr. 
Johnson  ;  and  what  follower  of  medicine  can 
forget  that  the  immortal  sage  of  Cos,  by  the 
example  which  he  afforded  in  his  well-spent 
life,  disarmed  his  own  antithesis  of  its  woful 
point:   o  /3/o? 


BIBLIOGRAPHY.  —  Lord  Bacon,  Historia  vitze  ct 
mortis.  Pollich,  Diss.  de  nutrimento,  incremento, 
statu,  et  decremento  corp.  hum.  4to.  Strasb.  1763. 
Ploucquet,  Diss.  sistens  aetates  humanas  eorumque 
jura,  4to.  Tubing.  1778  ;  (Recus  in  Frank  Delect. 
Opuseul.  vol.  vii.)  Daignan,  Tableau  des  varietes 
de  la  vie  bum.  2  vol.  8vo.  Par.  1786.  Rush,  Med. 
inquiries,  vol.  iv.  Esparron,  Ess.  sur  les  ages  de 
rhomme,  Thes.  de  Paris,  an.  xi.  Ranque,  Des 
predominances  organiques  des  differens  ages,  Thcs. 
de  Par.  1803.  Wesener,  Spec.  hist,  hominis  varias 
ejus  periodos,  &c.  sistens,  8vo.  Kraebcrg.  1804. 
Lucce,  Grundriss  der  Entwickelungsgeschichte  des 
menschlichen  Kb'rpers.8vo.  Marburg,  1819.  Burdach, 
Die  Physiologie  als  Erfahrungswissenschaft,  8vo. 
Leipz.  1803.  Renauldin,  Diet,  des  Sc.  Med.  art. 
<  Age/  Rullier,  Diet,  de  Med.  art.  '  Ages/  Begin, 
Diet,  de  Med.  et  Chir.  Prat.  art.  'Age/  Roget, 
Cyc.  of  Pract.  Med.  art.  <  Age/  Copland's  Diet. 
art.  '  Age/  Also  the  anatomical  and  physiological 
systems  of  Adelon,  Beclard,  Bichat,  Bostoch,  &c. 

(J.  A.  Symonds.) 
ALBINO.  ($yn.Albinismus,leucopathia,  Icu- 


a  prejudice.     Every  consideration  of  the  fact  in  cathiopia). — This  term,  as  employed  in  phy- 

question  with  reference  to  the  universe  must  siology,  appears  to  have  been  first  used  by  the 

"justify  the  ways  of  God  to  man"  in  the  dis-  Portuguese*  to  designate  a  peculiar  condition 

position  of  this  as  of  every  other  event.  We  have  of  the  human  body,  which  was  occasionally 

only  to  conceive  the  circumstance  altered,  in  cor-  observed  among  the  negroes   in   the  west< 

respondence  to  the  idle  wish  of  some  aspirant  parts  of  Africa.     It  consists  in  the  skin  and 

,  ..  i  .1  , 1     • -1««  *,  i  /* j.1 .l.Ii/t         nrVhil/*       in        fllO 


to  longevity,  and  we  see  that  every  thing  else 
also  would  require  to  be  changed ;  that,  in 
short,  the  beautiful  arrangements  of  the  world 
and  of  our  social  relations  would  be  broken. 
To  notice  one  or  two  of  these :  if  the  life  of 
man  were  longer  than  it  now  is,  his  progeny 
would  need  to  be  greatly  abridged  from  their 
present  numbers,  or  they  would  soon  exceed 


the  hair  being  perfectly  white,  while  in  the 


*  Vossius,  de  Nili  origine,  cap.  19.  p.  69 ;  see 
also  Ludolf,  Hist,  ^tbiop.  Com.  lib.  i.  cap.  14. 
No  100  p.  197.  The  name  by  which  the  African 
Albinoes  are  known  among  their  countrymen 
Dondos  :  by  the  French  they  are  frequently  termed 
Blafards. 

G    '/ 


84 


ALBINO. 


form  of  the  features  and  in  all  other  respects 
the  individuals  in  question  exactly  resemble 
the  negro  race.  Another  striking  peculiarity 
of  the  Albino  is  the  state  of  the  eye,  which  is 
of  a  delicate  pink  or  rose  colour ;  it  is  likewise 
so  sensible  to  light  as  to  be  unable  to  bear  the 
ordinary  light  of  the  day,  while  in  the  evening, 
or  in  a  dark  shade,  its  functions  appear  to  be 
sufficiently  perfect.  We  learn  from  Wafer, 
who  accompanied  Dam  pier  in  one  of  his  voy- 
ages, and  who  relates  his  adventures  in  crossing 
the  Isthmus  of  Darien,  that  Albinoes  are  not 
unfrequently  found  among  the  inhabitants  of 
this  district.*  We  are  also  informed  by  various 
travellers  and  naturalists  that  they  are  often 
met  with  in  some  of  the  oriental  isles,  more 
especially  in  Java  and  Ceylon  ;f  in  all  these 
cases  exhibiting  the  peculiar  appearance  of  the 
skin,  hair,  and  eyes,  while,  in  other  respects, 
they  conformed  to  the  external  and  physical 
characters  of  the  people  among  whom  they  are 
found.  The  same  circumstance  occurs  in  this 
country  and  in  the  other  parts  of  Europe,  al- 
though, if  we  are  to  place  any  confidence  in 
the  accounts  of  travellers,  the  Albino  is  much 
more  frequently  met  with  in  tropical  climates, 
especially  in  the  western  parts  of  Africa,  and 
in  Darien,  than  in  the  more  northern  regions.^ 

*  Wafer's  New  Voyage,  p.  134 ..  8  ;  Buffon,  Hist. 
Nat.  t.  iii.  p.  500;  WoodVTrans.  v.  iii.  p.  419,  10  ; 
Pauw,  Recherches  sur  les  Americains,  par.  4, 
sect.  1.  t.  ii.  p.  1  et  seq.  ;  Raynal,  Hist,  des  Indes, 
t.  iii.  p.  288.  The  earliest  account  which  we  have 
of  the  South  American  Albinoes  is  by  Cortez,  in 
the  narrative  of  his  conquest  of  Mexico,  which  he 
transmitted  to  Charles  V.  In  describing  the  palace 
of  Montezuma,  among  other  objects  of  rarity  or 
curiosity  which  were  found  in  it,  he  says,  "  In  hujus 
palatii  particula  tenebat  homines,  pueros,  fcemi- 
nasque  a  nativitate  candidos  in  facie,  corpore,  ca- 
pillis,  superciliis,  et  palpebris."  De  Insulis  nuper 
inventis  narrat.,  p.  30  of  "  Nar.  Sec. ;"  see  also 
Clayton,  in  Manch.  Mem.  v.  iii.  p.  261  et  seq. 

t  Buffon,  t.  iii.  p.  399  and  415  :  Wood's  Trans. 
v.  iii.  p.  328,  9  and  344.  We  have  not  been  able 
to  procure  the  "  Voyages  de  Legal,"  which  is  re- 
ferred to  by  Buffon  and  others,  as  containing  the 
original  account  of  the  Albinoes,  or,  as  they  have 
been  termed,  Chacrelos,  of  Java.  With  respect  to 
the  Bedas  of  Ceylon,  as  originally  described  by 
Ribeyro,  Hist,  de  Ceylon,  ch.  xxiv.,  and  more 
lately  by  Percival,  Account  of  Ceylon,  ch.  13,  and 
by  Cordiner,  Desc.  of  Ceylon,  v.  i.  c.  4,  it  seems 
evident  that  they  are  not  to  be  considered  as  Albi- 
noes. The  only  remark  which  Ribeyro  makes  on 
their  physical  character  is,  "  Us  sont  blancs  comme 
des  Europeens,  et  il  y  a  meme  des  roux  parrai 
eux,"  p.  178.  Percival,  who  saw  some  of  them, 
states  that  their  complexions  are  fairer  and  more 
inclined  to  a  copper  colour,  than  those  of  the  other 
inhabitants  ;  while  all  that  is  said  by  these  writers 
respecting  their  habits  and  modes  of  life  indicates 
that  they  are  a  distinct  race  or  tribe.  The  term 
Beda,  or  Badah,  appears  to  be  a  corruption  of 
Vaddah,  or  Veddah,  which  Knox  informs  us  is  the 
name  of  the  aborigines  of  the  island ;  Account  of 
Ceylon,  p.  61  ;  see  also  Brown,  in  Brewster's 
Encyc.  art.  "  Ceylon,"  p.  704  ;  Cordiner  and  Per- 
cival, ut  supra. 

t  Vossius  and  Ludolph,  ubi  supra  ;  Argensola, 
Conquist.  de  las  Islas  Malucas,  lib.  ii.  p.  71, 
speaks  of  Albinoes  as  not  uncommon  in  these  islands; 
De  la  Croix,  Relation  de  1'Afrique,  par.  iii.  liv.  ii. 
sect.  ii.  $.  13,  "  Albinos,  hommes  blancs,  ou 


We  meet  with  a  few  scattered  remarks  in  the 
writings  of  the  ancients,  which  render  it  evident 
that  this  peculiar  state  of  the  human  body  had 
fallen  under  their  notice.  We  have  the  follow- 
ing passage  in  Pliny :  "  Idem  "  (Isigonus 
Nicaeensis)  "  in  Albania  gigni  quosdam  glauca 
oculorum  acie,  e  pueritia  statim  canos,  qui 
noctu  plus  quam  interdiu  cernant."*  The  same 
circumstance  is  referred  to  by  Aulus  Gellius  : 
"  . .  . .  in  ultima  quadain  terra,  quae  Albania 
dicitur,  gigni  homines,  qui  in  pueritia  canescunt, 
et  plus  cernunt  oculis  per  noctem,  quam 
inter  diem  ;"f  and  by  Solinus :  he  says  that  the 
Albanians  "  albo  crine  nascuntur ;"  "  glauco 
oculis  inest  pupula,  ideo  nocte  plus  quam  die 
cernunt."]:  Pliny,  in  speaking  of  the  inhabi- 
tants of  a  certain  district  in  the  interior  of 
Africa,  names  them  Leucaethiopes  ;§  and,  as  it 
has  been  supposed  that  in  this  passage  he 
referred  to  the  Albinoes,  the  term  has  been 
applied  to  them  by  some  eminent  modern 
naturalists; ||  but  it  appears  more  probable  that 
the  Leucaethiopes  were  a  tribe  of  negroes 
whose  complexion  was  rather  less  dark  than  that 

Mores  blancs,"  informs  us  that  they  compose  a 
considerable  body  of  attendants  at  the  court  of  the 
king  of  Loango  ;  the  same  statement  is  made  by 
Ludolf,  ubi  supra,  and  by  the  author  of  the  Hist. 
Gen.  des  Voyagesj  t.  vi.  p.  250  et  seq. :  Bowdich, 
Mission  to  Ashantee,  p.  292,  observes,  that  the 
king  had  at  his  court  "  nearly  one  hundred  negroes 
of  different  colours,  through  the  shades  of  red 
and  copper  to  white ;"  he  adds  that  they  were 
"  generally  diseased  and  emaciated ;"  some  of 
these  were  probably  Albinoes.  Cook,  in  his  first 
voyage,  saw  six  Albinoes  in  the  small  population 
of  Otaheite,  v.  ii.  p.  188 ;  in  his  second  voyage 
he  saw  one  in  New  Caledonia,  v.  ii.  p.  113,  4 ; 
and  in  his  third  voyage,  he  met  with  three  in  the 
Friendly  Isles,  v.  i.  p.  381,  2.  These,  it  may  be 
remarked,  must  have  belonged  to  the  Malayan 
variety.  See  also  Winterbottom,  Account  of  Sierre 
Leone,  v.  ii.  p.  166  et  seq. ;  Stevenson,  in 
Brewster's  Encyclopaedia,  art.  "  Complexion," 
p.  41,  2;  Bory  St.  Vincent,  L'Homme,  t.  ii. 
§.  "  Hommes  Monstreux,"  p.  143-7 ;  also  in  Diet. 
Class.  d'Hist.  Nat.  art.  "  Homme,"  p.  166  et 
seq.;  Renauldin,  in  Diet,  des  Scien.  Med.  art. 
««  Albino  ;"  Lawrence's  Lect.  p.  287  ;  Is.  St.  Hi- 
laire,  Anom.  de  1'Organization,  t.  i.  par.  ii.  liv.  iii. 
ch.  i.  p.  296,  314,  5,  and  art.  "  Mammiferes,"  in 
Diet.  Class.  d'Hist.  Nat.  p.  113.  Some  of  the 
earlier  writers  did  not  hesitate  to  affirm,  that  they 
were  confined  to  the  offspring  of  negroes,  Monge, 
Journ.  Phys.  1782,  p.  401  et  seq.  Suppl.  We 
have  no  very  distinct  account  of  Albinoes  among 
the  Chinese  and  Mongols,  but  they  appear  to  be 
as  frequent  among  the  Malays  and  native  Americans 
as  among  the  ^Ethiopians. 

*  Hist.  Nat.  lib.  7.  cap.  2.  See  the  note  of 
Cuvier,  in  his  edition  of  7th  .  .  llth  books  of 
Pliny,  t.  i.  p.  18. 

t  Noct.  Attic,  lib.  9.  cap.  4. 

t  Polyhistor,  cap.  15.  p.  25.  See  the  remarks 
of  Saumaise,  Exerc.  Plin.  p.  134,  and  of  Pauw, 
t.  ii.  note  in  p.  13. 

§  Lib.  5.  cap.  8.  We  also  find  the  same  term  in 
Pomponius  Mela,  lib.  1.  cap  4,  and  in  Ptolemy, 
Geog.  lib.  4.  cap.  6;  but  it  is  not  accompanied  by 
any  description  of  the  people  so  designated. 

[I  Among  others  by  Bltimenbach,  Gen.  hum. 
var.  §  78.  See  Is.  St.  Hilaire,  p.  297,  note.  We 
may  remark  that  the  term  is  objectionable,  as  indi- 
cating that  the  Albino  is  confined  to  the  ^Ethiopic 
variety. 


ALBINO. 


85 


of  the  Africans  generally.*  It  has  been  like- 
wise supposed  that  Celsus  alluded  to  the  Al- 
bino, when  he  speaks  of  a  peculiar  condition 
of  the  skin  under  the  name  of  Leuce  ;f  but 
this  appears  to  be  a  morbid  cutaneous  affection, 
and  to  have  no  reference  to  the  subject  now 
under  consideration. 

From  the  number  of  Albinoes  which  were 
supposed  to  exist  in  certain  countries,  as  well 
as  from  the  marked  peculiarity  in  their  ap- 
pearance, an  opinion  was  long  entertained  that 
they  formed  a  distinct  race  or  variety  of  the 
human  species,};  originating  in  some  unknown 
cause,  and  bearing  the  same  relation  to  the 
other  inhabitants  of  the  countries  in  which 
they  are  found  that  the  acknowledged  varieties 
of  the  human  species  bear  to  each  other.  But 
this  opinion,  although  sanctioned  by  high 
authority,  may  be  considered  as  decisively 
disproved  by  the  well-ascertained  fact,  that 
Albinoes  are  born  of  parents  who  do  not  possess 
this  characteristic  peculiarity  of  the  skin,  hair, 
and  eyes.§ 

Although  Albinoes  are  of  comparatively  rare 
occurrence  in  Europe,  yet  we  have  had  a  suffi- 
cient number  of  examples  to  render  us  per- 
fectly familiar  with  the  appearance  which  they 
present,  and  with  the  precise  nature  of  the 

*  See  the  note  of  Hardouin  in  loco,  Valpy's  ed. 
p.  1285,  Le  Maire's,  t.  ii.  p.  438  ;  also  the  remark 
of  M.  Marcus  in  M.  Ajasson's  Trans,  of  Pliny, 
t.  iv.  p.  185.  It  is,  perhaps,  to  this  lighter  coloured 
negro,  rather  than  to  the  proper  Albino,  that  we 
must  refer,  in  part  at  least,  the  accounts  which  are 
given  by  travellers  of  the  great  number  of  white 
Africans  that  have  been  collected  in  certain  situa- 
tions. We  may  remark  that  all  accounts  of  Albi- 
noes that  are  given  in  general  terms  only,  should  be 
received  with  a  certain  degree  of  caution,  unless  the 
peculiar  state  of  the  eye  is  distinctly  noticed. 
Humboldt  .remarks  that  the  missionaries,  when 
they  tmet  with  any  Indians  that  were  less 
black  than  ordinary,  were  accustomed  to  call  them 
white  ;  Pers.  Nar.  by  Williams,  v.  iii.  p.  287  et 
seq.  See  Prichard,  in  Medical  Cyclop.  Art.  "  Tem- 
perament," p.  163. 

t  De  Medicina,  lib.  5.  cap.  28.  §  19. 

$  This  appears  to  have  been  the  case  even  with 
Haller,  El.  Phys.  xvi.  4.  13.  p.  492.  Voltaire  main- 
tains this  hypothesis,  Essai  sur  les  moeurs,  (Euvr. 
t.  xiii.  Introd.  and  p.  7,  8.  Buffon  inclines  to  it; 
but  his  opinion  on  this  point  is  not  decided  or 
uniform,  t.  iii.  p.  501.  See  Is.  St.  Hilaire,  p.  295. 

$  In  addition  to  the  authors  already  referred  to, 
we  have  a  case  of  this  kind  by  Helvetius,  Hist. 
Acad.  Sc.  1734,  p.  15  .  .  7.  The  Albiness  described 
by  Buffon  was  born  of  black  parents :  see  also 
Castillon,  in  Berlin  Mem.  1762,  p.  99  .  .  105  ;  Dic- 
quemarc,  Journ.  Phys.  1?77,  p.  357  .  .  0,  and  1788, 
p.  301  et  seq.  ;  Hist.  Acad.  Scien.  1744,  p.  12,  3; 
and  Maupertuis,  Ven.  Phys.  p.  135  etseq.  :  Jeffer- 
son, Notes  on  Virginia,  p.  103  . .  5,  mentions  an  in- 
stance of  three  Albino  sisters  born  of  black  parents  ; 
two  of  these  had  black  children  ;  Firmin,  Descrip.  de 
Surinam,  t.  i.  p.  153,  5  ;  Goldsmith's  Anim.  Nature, 
t.  i.  p.  452,  3  ;  Brue,  Hist,  des  Voyages,  t.  iii. 
p.  370,  0.  See  on  this  point  Is.  St.  Hilaire,  p.  303. 
We  have  a  decisive  proof  that  the  peculiarity  of 
the; Albino  is  merely  accidental  and  individual, 
and  does  not  constitute  a  distinct  variety,  in  the 
state  of  the  offspring  of  an  Albino  and  a  black 
negro,  which  is  not  intermediate  between  the  two, 
as  in  the  case  of  the  Mulatto ;  Hunter,  on  the 
Anim.  (Econ.  p.  248  ;  Is.  St.  Hilaire,  p.  305.. .7. 


circumstances  which  characterize  them.*  The 
skin  is  of  a  milky  whiteness,  without  the 
slightest  admixture  of  the  brown  or  olive  tint 
which  is  found  in  the  complexion  of  even  the 
fairest  European  female ;  the  hair  is  also  per- 
fectly white,f  and  's  generally  of  a  soft  or 
silky  texture,  while  all  the  coloured  parts  of 
the  eye  are  of  a  delicate  rose  colour.  We 
are  informed  that  the  skin  of  the  African  and 
American  Albino  is  not  only  completely  free 
from  any  shade  of  brown  or  olive,  but  that  it 
is  also  devoid  of  the  pink  tinge  which  is  found 
more  or  less  in  the  complexion  of  the  European. 
It  would  appear,  likewise,  that  the  skin  of 
the  tropical  Albino  is  frequently  in  a  diseased 
state,  being  /covered  with  scales  of  a  leprous 
nature,  and  with  a  serous  exudation,  which 
proceeds  from  the  fissures  or  clefts  that  take* 
place  in  various  parts  of  the  surface.}: 

It  has  been  a  very  general  opinion,  that  be- 
sides the  peculiar  state  of  the  integuments,  the 
Albino  possesses  a  general  delicacy  of  habit 
and  constitution,  and  that  he  exhibits  a  defici- 
ency even  of  mental  power.§  For  this  latter 
opinion  there  appears  to  be  no  sufficient  foun- 
dation, and  with  respect  to  the  former  we  may 
remark,  that  any  general  weakness  of  the  phy- 
sical frame,  if  it  be  actually  found  to  exist,  may 
be  probably  referred,  at  least  in  some  degree, 
to  the  peculiar  condition  of  the  eyes  and  the 
skin,  which  are  not  well  adapted  either  to  a 


*  We  have  a  copious  list  of  references  in  Blu- 
menbach,  p.  278  . .  0,  in  Lawrence,  p.  281  .  .  9,  and 
in  Is.  St.  Hilaire,  ut  supra  and  $.  5.  One  of  the 
earliest  of  what  may  be  considered  as  the  correct 
descriptions  is  that  of  Buffon,  Supp.  t.  iv.  p.  559 
et  seq.  The  descriptions  of  Blumenbach,  $.  78, 
and  of  Saussure,  Voy.  §.  1037 . .  .  1043,  are  par- 
ticularly correct  and  characteristic  :  to  this  we  may 
add  the  more  recent  account  of  Is.  St.  Hilaire,  t.  i. 
par.  2,  liv.  3.  ch.  1,  §.  2  and  5.  We  are  informed 
by  Ludolf,  ubi  supra,  that  the  first  modern  writer 
who  distinctly  mentions  the  Albino  is  Tellez. 

f  Blumenbach  particularly  characterizes  the 
whiteness  of  the  hair  of  the  Albino  as  being  "  gilva, 
colori  cremoris  lactis  quodammodo  comparanda," 
p.  275. 

|  See  Vossius,  Ludolf,  De  la  Croix,  Cook's  First 
Voyage,  and  Winterbottom,  ut  supra ;  Blumen- 
bach,  p.  274  ;  Buffon,  in  Hist.  Acad.  Scien.  1760, 
p.  17 ;  St.  Hilaire,  p.  304,  5 :  Wafer,  in  his  de- 
scription of  the  white  inhabitants  of  Darien,  p.  134, 
et  seq.,  says  that  there  is  a  white  down  on  their 
skin. 

$  Wafer,  p.  134-8  ;  Buffon,  t.  iii.  p.  503  ;  Wood's 
Trans,  vol.  iii.  p.  420  ;  Voltaire,  t.  xv.  p.  269,70- 
Pauw,  t.  ii.  p.  9,  10;  Raynal,  t.  iii.  p.  288;  Du- 
bois  on  the  People  of  India,  ch.  xv.  p.  199  et  seq.  ; 
Firmin,  t.  i.p.  153. .  5;  Dalin,  in  Amoen.  Acad.  t.  vi. 
p.  74,  note  ;  Isert,  Voy.  en  Guinee,  ch.  xv.  p.  199 
et  seq.  ;  Labillardiere,  Voyage,  t.  ii.  p.  141  ;  Win- 
terbottom, «t  supra ;  Rayer,  sur  le  Peau,  t.  ii. 
p.  193  . .  203  ;  Blandin,  Diet.  Med.  Chir.  Pr*c.  "Al- 
binie;"  Breschet,  Diet,  de  Med.  "  Albino;'' 
Sonini,  in  his  edition  of  Buffon,  t.  xx.  p.  355-6, 
note.  So  far  as  regards  the  state  of  the  intellect, 
the  charge  is  repelled  by  M.  Sachs,  who  gives  a 
minute  account  of  the  peculiarity  in  his  own  person 
and  that  of  his  sister  ;  Hist.  Nat.  duor.  Leuca3thio- 
pum.  Jefferson  informs  us,  that  the  Albinesses,  of 
whioh  he  gives  an  account,  were  "  uncommonly 
shrewd,  quick  in  their  appehension  and  reply," 
p.  103-5. 


ALBINO. 


bright  light  or  to  a  high  temperature,  and  there- 
fore render  the  individuals  less  able  to  bear 
exposure  to  the  weather,  or  to  perform  the 
ordinary  occupations  of  life.  To  the  same 
cause  may  be  ascribed  the  morbid  condition  of 
the  skin,  which,  as  was  remarked  above,  occurs 
not  unfrequently  in  hot  climates,  and  which  is 
not  observed  in  the  European  Albino.  Partly 
from  the  circumstances  stated  above,  and  partly 
from  the  idea  of  imperfection  or  defect,  which 
is  connected  with  their  appearance,  the  tropical 
Albino  is  generally  regarded  by  his  country- 
men with  a  degree  of  compassion  or  even  of 
contempt  ;*  and  hence  is  derived  one  of  their 
popular  denominations,  chacrelas,  which  is  a 
corruption  of  kakkerlakken,  the  Dutch  name 
for  the  cock-roach,  as  being,  like  those  animals, 
able  to  leave  their  haunts  only  in  the  evening.^ 
Besides  the  complete  Albino,  which  we  have 
now  described,  there  are  occasional  examples 
of  individuals,  where  the  whiteness  of  the  skin 
exists  in  certain  parts  of  the  surface  only,  while 
the  remainder  of  the  body  is  of  its  ordinary 
colour 4  In  the  majority  of  cases  the  peculi- 
arities which  constitute  the  Albino  are  connate, 
and  continue  during  life  without  any  change. 
There  are,  however,  some  instances,  where  the 
whiteness  of  the  skin  does  not  exist  at  birth, 
but  makes  its  appearance  at  a  subsequent  pe- 
riod, generally  by  slow  degrees,  until  the  com- 
plete Albino  character  is  induced. §  When 

*  Vossius,  p.  68,  informs  us  that  they  are  avoided 
by  the  other  negroes,  as  supposed  to  be  diseased. 
De  la  Croix  says  the  negroes  regard  them  as  mon- 
sters, and  do  not  permit  them  to  multiply,  ut  supra. 
Dubois,  p.  199  et  seq.  observes  that  they  are  named 
lepers  by  birth,  and  that  when  they  die  their  bodies 
are  not  buried  or  burnt,  but  cast  on  dunghills.  See 
also  Firmin,  ubi  supra. 

t  Blumenbach,  p.  277 :  Lawrence,  p.  287 :  St. 
Hilaire,  p.  296. 

J  Phil.  Trans,  vol.  xix.  p.  781,  and  Lowthorpe's 
Abridg.  vol.  iii.  p.  8  ;  Buffon,  t.  iv.  p.  565.  tab.  2,  et 
p.  571, 'tab.  3  ;  Arthaud,  in  Journ.  Phys.  1789 .!pt.  2. 
p.  277,8  ;  Rush,  in  Amer.  Trans,  vol.  ii.  p.  392  et 
seq.  ;  Gumilla,  El  Oron.  Ilus.  t.  i.  p.  109  et  seq.  ; 
Ditto,  Hist,  de  1'Oronoque,  trad.  t.  i.  p.  150  et  seq.  ; 
Jefferson,  p.  105 ;  Blumenbach,  §  48 ;  Rayer,  ut 
supra  ;  Is.  St.  Hilaire,  p.  309  et  seq.  ;  Isert,  p.  156. 
Bell,  in  Travels  in  Asiatic  Russia,  p.  217,8,  saw 
a  number  of  persons  -with  white  spots  oil  the  skin, 
but  it  seems  probable  that  this  was  the  effect  of 
some  cutaneous  disease.  The  partial  Albino  appears 
to  have  been  ;  noticed  by  the  ancients ;  Lucian, 
Prometh,  t.  i.  p.  15. 

§  Blumenbach,  p.  276,  says  it  is  "  semper  con- 
natus ;"  see,  also,  Lawrence,  p.  285.  There  are, 
however,  certain  well  authenticated  cases,  where 
the  skin  of  the  negro  has  gradually  changed  its  co- 
lour from  black  to  white  ;  sometimes  the  change 
has  been  general,  sometimes  only  partial ;  Bates, 
in  Phil.  Trans,  vol.  li.  p.  175  et  seq.  ;  Gualtier,  in 
Journ.  Phys.  t.  Ixx.  p.  248  et  seq.  ;  Le  Cat,  sur  le 
Peau,  p.  112  et  seq.  ;  Rayer,  ut  supra  ;  Fisher,  in 
Manch.  Mem.  vol.  v.  p.  314  et  seq.  ;  Rush's  Re- 
marks on  the  same,  Amer.  Trans,  vol.  iv.  p.  289 
et  seq.  In  one  of  the  four  cases  which  are  men- 
tioned by  Le  Cat,  the  change  of  colour  appears  to 
have  been  the  consequence  of  a  severe  burn  or  scald. 
Besides  the  partial  Albino,  we  have  what  has  been 
termed  the  imperfect  Albino,  where  the  peculiarity 
exists  in  a  certain  degree  only  ;  Is.  St.  Hilaire,  $.  4. 
p.  312  ct  seq. 


once  formed  it  does  not  seem  that  it  ever  dis- 
appears, or  is  even  in  any  degree  diminished, 
nor  have  we  any  authentic  accounts  of  its  being 
removed  by  any  constitutional  change,  either 
natural  or  morbid,  or  by  external  applications. 

Although,  as  has  been  stated  above,  this 
peculiarity  occurs  in  individuals,  who  did  not 
derive  it  from  their  parents,  yet,  like  all  those 
deviations  from  the  ordinary  structure  of  the 
body,  which  have  been  styled  accidental  varie- 
ties, when  once  produced,  it  is  disposed  to 
propagate  itself  by  hereditary  descent.  There 
are  also  certain  individuals,  who  have  a  ten- 
dency to  produce  it;  so  that  even  among  the 
few  European  Albinos,  of  which  we  have  a 
minute  account,  we  have  cases  of  its  occurrence 
in  two  or  more  members  of  the  same  family, 
either  as  connected  by  parental  descent,  or  by 
collateral  relationship.*  We  have  no  instance 
on  record  of  the  offspring  of  a  male  and  female 
Albino. 

The  whiteness  of  the  skin  and  hair,  both 
general  and  partial,  is  not  confined  to  the  hu- 
man race  ;  it  is  found  in  most,  if  not  in  all  the 
species  of  the  mammalia,  and  in  some  of  these, 
as  in  the  dog,  the  horse,  and  the  rabbit,  is  the 
subject  of  daily  observation  ;f  in  most  of  them, 
however,  the  peculiar  state  of  the  eye  does  not 
exist.  These  white  varieties,  like  other  analogous 
cases  among  the  lower  animals,  when  once 
produced,  are  strictly  hereditary,  in  which  re- 
spect they  differ  somewhat  from  the  human 
Albino. 

Various  opinions  have  been  entertained  by 
physiologists  respecting  the  nature  of  this  pecu- 
liarity, whether  it  should  be  considered  as  a 
morbid  affection,^  depending  upon  a  diseased 
state  of  the  constitution,  and  also  respecting 
its  immediate  or  efficient  cause.  The  first  of 
these  points  may  be  regarded  as  a  verbal  con- 
troversy, depending  altogether  upon  our  defi- 
nition of  morbid  action ;  but  we  conceive,  that 
according  to  the  ordinary  definition  of  the  term, 
we  should  not  consider  it  as  a  disease,  but  as  a 
connate  deviation  from  the  perfect  structure  of 
the  animal  frame,  not  produced  by  an  external 
cause,  and  not  removable  by  a  remedial  agent. 
For  a  correct  knowledge  of  its  physical  cause, 
we  are  indebted,  in  the  first  instance,  to  an  in- 
genious conjecture  of  Blumenbach's,  who  ac- 
counted for  the  red  colour  of  the  eye,  and  its 
extreme  sensibility  to  light,  by  the  absence  of 
the  pigmentum  nigrum.§ 

*  See  particularly  Saussure's  account  of  the  two 
boys  of  Chamouni  and  Sachs's  Narrative  ;  also  Blu- 
menbach, p.  276  and  279,  note  ;  Firmin  and  Jeffer- 
son ut  supra  ;  Pauw,  t.  ii.  p.  25  ;  Bory  St.  Vincent, 
L'Homme,  'p.  144,  mentions  an  Albino  of  the  third 
generation;  Is.  St.  Hilaire,  passim. 

t  Blumenbach,  p.  281,  2 :  Is.  St.  Hilaire,  p. 
297..  9. 

|  "  Ad  cachexias  referenda  videtur  affectio," 
Blumenbach,  p.  274  ;  Is.  St.  Hilaire,  §.  6,  supposes 
that  there  are  two  species  of  Albinism,  one  the  eifect 
of  disease,  the  other  a  true  anomaly ;  but  we  con- 
ceive that  the  term  is  not  correctly  applied  to  the 
former  state. 

§  Comment,  de  Oculis  Leucaethiopum,  et  De 
Gen.  Hum.  var.  §.  78. 


ALBINO. 


87 


This  conjecture  was  shortly  after  verified  by 
Buzzi  of  Milan,  who  took  advantage  of  an 
opportunity  which  presented  itself,  of  dissecting 
the  eye  of  an  Albino,  in  which  the  pigmentum 
nigrum  could  not  be  detected.*  He  also  ex- 
amined the  structure  of  the  skin,  which  appeared 
to  be  deprived  of  the  rete  mucosum,  that  part 
of  it  in  which  its  specific  colour  is  supposed  to 
reside  ;  the  hair  was  also  found  to  be  deficient 
in  its  central  coloured  part.f  Whether,  in 
these  cases,  the  pigmentum  nigrum  of  the  eye 
and  the  rete  mucosum  of  the  skin  are  absolutely 
deficient,  or  are  only  deprived  of  their  colouring 
matter,  so  as  not  to  be  detected  by  the  eye,  is  a 
point  on  which  different  opinions  have  been 
formed  by  anatomists ;  J  perhaps,  upon  the 
whole,  we  may  be  induced  to  consider  the  lat- 
ter opinion  as  the  most  probable. 

What  are  the  circumstances  in  the  consti- 
tution of  the  parents  which  should  lead  to  this 
peculiarity  in  their  offspring  is  entirely  un- 
known, nor  have  any  conjectures  been  formed 
on  the  subject  which  can  be  considered  as  even 
plausible.§  The  hypothesis  of  Buffon,  which 
at  one  time  obtained  a  considerable  degree  of 
credit,  that  white  is,  as  it  were,  the  primitive 
colour  of  nature,  which,  by  various  external 
causes,  is  changed  to  brown  or  black,  but  which 
the  body  has  always  a  tendency  to  resume 
under  favorable  circumstances,) |  is  completely 
without  foundation  :  nor  does  it  appear  that 
we  can  explain  it  upon  the  principle,  that  do- 
mestication and  the  habits  of  civilized  life  have 
a  tendency  to  produce  a  lighter  shade  of  the 
complexion,  because  we  trace  no  connexion 
between  the  supposed  cause  and  the  effect, 

*  For  some  remarks  "  on  the  colour  of  the  pigment 
of  the  eye,"  and  its  effect  on  vision,  as  applicable 
to  the  eye  of  the  Albino,  see  Hunter,  p.  243  .  .  253  ; 
also  Blumenbach,  $.  51.  "  Capillorum  cum  cute 
consensus,"  and  §.  53,  ' '  Irides  oculorum  cum  capil- 
lorum  colore  consentientes." 

t  Sachs  gives  us  a  minute  account  of  the  analysis 
of  the  hair  of  the  Albino,  compared  with  Vatiquelin's 
analysis  of  hair  in  its  ordinary  state,  from  which  it 
appears  that  no  iron  could  be  detected  in  it. 

j  Blandin,  Diet.  Med.  Chir.  Prat.  «'  Albinee ;" 
Rayer,  §.  630. 

§  Mansfeldt  is  disposed  to  ascribe  the  production 
of  the  Albino  state  to  some  shock  given  to  the 
foetus,  by  an  impression  made  upon  the  mother  ;  it 
is  characterized  as  a  "  cessation  totale,  momentanee 
d'action  cerebrale  ;  "  Journ.  Compl.  t.  xv.  p.  250  et 
seq.  Is.  St.  Hilaire  essentially  adopts  this  hypo- 
thesis, ascribing  the  peculiar  state  of  the  skin  to  an 
"  arret  de  developpement,"  in  consequence  of  which 
the  colouring  matter  is  not  formed  at  the  requisite 
period,  p.  319,0.  The  idea,  that  it  depends  upon 
something  peculiar  in  the  seminal  matter  of  the 
parent,  which  was  maintained  by  Herodotus,  Thalia, 
$.  101,  and  was  controverted  by  Aristotle,  Hist. 
Animal,  lib.  3.  cap.  22,  has  been  revived  by  Mau- 
pertuis,  Diss.  2,  and  by  Pauw,  t.  i.  p.  179,  and  t.  ii. 
p.  21.  Le  Cat  refers  the  colour  of  the  negro  to  a  pecu- 
liar substance,  which  he  names  "  ^thiope  animal," 
which  he  supposes  is  contained  in  their  fluids,  ana- 
logous to  the  black  inky  matter  of  the  cuttle  fish  ; 
par.  2.  art.  1 ;  the  absence  of  this  substance  con- 
verts the  negro  into  an  Albino. 

||  T.  iii.  p.  502,3. ;  Wood's  trans,  t.  iii.  p.  422. 
We  may  remark  that  this  speculation  of  Buffon's  is 
precisely  the  reverse  of  that  of  Hunter,  p.  243  et 
seq. 


and  because  the  production  of  the  Albino  is 
complete  in  the  first  instance,  and  not  brought 
about  by  any  gradual  or  progressive  alteration. 
It  appears  that  we  must  come  to  the  con- 
clusion, that  although  the  anatomical  or  phy- 
sical cause  of  the  peculiarity  is  ascertained,  yet 
that  we  are  entirely  ignorant  of  its  remote 
cause,  or  of  that  train  of  circumstances  which 
leads  to  its  production.* 

*  "  The  following  cases  have  not  been  referred 
to  in  the  body  of  the  article;  DelaNux,  Hist. 
Acad.  Scien.  1744,  p.  13;  Camelli,  Phil.  Trans. 
v.  xxv,  p.  2268;  Duddell  on  the  Eye,  Suppl.  to, 
sect.  iii.  $.  30  et  seq.  ;  Percival,  Irish  Trans,  v.  iv. 
p.  97,  8  ;  Hunter,  Anim.  (Econ.  p.  250,  1  ;  Traill, 
in  Nich.  Journ.  v.  xix,  with  an  Add.  by  the  editor  ; 
Mansfeldt,  Journ.  Compl.  t.  xv  ;  Ansieux,  in  Journ. 
Med.  de  Corvisart,  t.  xiv,  p.  263,  4. 

For  the  following  epitaph,  which  appears  to  have 
been  written  on  an  Albino  child,  we  are  indebted 
to  a  literary  friend,  the  Rev.  Jos.  Hunter. 

•'  Upon  Thomas,  son  of  Ric.  Elmhurst  by  Mar- 
garet his  wife,  daughter  to  Ric.  Micklethwaite  : 
whose  promising  parts,  were  interrupted  by  an  early 
death. 

"  .  .  .  This  boy  no  Albiau  was,  yet  gray  hair'd 

borne 

Who  saw  old  age  and  night  as  soon  as  morne. 
His  grave's  a  cradle  ;  there  his  God  him  lay'd 
Betimes  to  sleep  lest  he  the  wanton  play'd. 
Bid  him  good  night !  i'th  bed  of  dust  sleep  on 
Until  the  morne  of  Resurrection. 

"  Anagram. 

"  Lo  Earth  misseth  me,  1632." 
From  the  Church  of  Worsborough,  Com.  York. 

BIBLIOGRAPHY. — Ansieux,  in  Journ.  Med.  de 
Corvisart,  t.  xiv.  Argensola,  Conquist.  de  las  Islas 
Malucas.  Lond.  1609.'  Aristoteles,  OperaaDuVal. 
Par.  1619.  Arthaud,  in  Journ.  Phys.  pour  1789. 
Bates,  in  Phil.  Trans,  v.  li.  Bell's  Travels.  Glas. 
1763.  Blandin,  in  Diet.  Med.  Chir.  Prac.  "Albinie." 
Blumenbach,  Gen.  Hum.  var.  (ed.  3.)  Gott.  1795; 
Ditto f  Comment,  de  Oculis  Leucaeth.  Gott.  1786. 
Bory  St.  Vincent,  in  Diet.  Class.  d'Hist.  Nat., 
"  Homme  ;"  Ditto,  1'Homme.  Par.  1827.  Bostock, 
in  Brewster's  Encyc.  "  Albino."  Bowdich,  Mis- 
sion to  Ashantee.  Lond.  1819.  Breschet,  in  Diet, 
de  Med.,  "  Albino."  Brown,  in  Brewster's  Encyc., 
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Buffon,  Hist.  Nat.  (ed.  2).  Par.  1750. ;  Ditto,  by 
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Exerc.  Plinian.  Traj.  ad  Rhen.  1689.  Stevenson, 
in  Brewster's  Encyc.  "  Complexion"  Traill,  in 
Nicholson's  Journ.  v.  xix.  Voltaire,  CEuvres.  Par. 
1819.  Vossius,  de  Nili  Origine.  Hag.  Com.  1666. 
Voyages,  Hist.  Gen.  des,  Haye,  1747.  Wafer's 
New  Voyage.  Lond.  1699.  Winterbottom's  Account 
of  Sierra  Leone.  Lond.  1803. 

(J.  Bostock.) 

ALBUMEN,  (Fr.Albumine,  Germ.  Eyweis- 
sstojf,)  is  one  of  the  most  important  proximate 
principles  of  animal  bodies ;  it  is  the  leading 
ingredient  of  the  blood,  of  many  of  the  secretions, 
and  of  muscular  fibre,  cartilage,  and  membrane : 
the  white  of  egg  (whence  the  generic  term  albu- 
men) presents  it  in  considerable  purity,  and  it 
is  from  this  source,  and  from  the  serum  of  the 
blood,  that  we  chiefly  obtain  it  for  the  purposes 
of  experiment.  In  this  article  we  shall  describe 
the  leading  properties  of  albumen;  and  in 
others,  refer  to  its  principal  modifications. 

The  white  of  egg  may  be  regarded  as  a 
combination  of  albumen  with  water ;  it  con- 
tains small  quantities  of  saline  substances, 
•which  are  inseparable  in  its  liquid  state.  When 
it  is  evaporated  at  a  temperature  below  120°, 
it  dries  into  a  brittle,  shining,  transparent  sub- 
stance of  a  pale  yellow  colour,  inodorous  and 
tasteless.  Its  ultimate  constituents,  exclusive 
of  saline  matters  and  a  trace  of  sulphur,  are 
carbon,  hydrogen,  nitrogen,  and  oxygen ;  of 
these  the  relative  proportions  have  been  deter- 
mined by  Gay  Lussac  and  Thenard,  who 
analysed  the  white  of  egg  dried  at  212°;  and 
by  Dr.  Prout,  who  employed  the  dried  serum 
of  slightly  inflammatory  blood  ;  the  following 
table  shows  its  theoretical  composition  as  con- 
trasted with  these  experimental  results  : — 


Atoms.  Equivs.  Theory. 

Carbon..  8       48  51.61 

Hydrogen  7         7  7.53 

Nitrogen    1       14  15.05 

Oxygen     3       24  25.81 


G.  Lussac.  Prout. 

52.883  50.00 

7.540  7.78 

15.705  15.55 

23.872  26.67 


1        93     100.00     100.000     100.00 


White  of  egg,  when  heated  to  about  150°, 
coagulates,  that  is,  it  becomes  a  white,  translu- 
cent, and  somewhat  elastic  substance,  which, 
when  cautiously  dried,  shrinks  up  and  assumes 
the  appearance  of  horn,  becoming  tough,  yel- 
lowish, and  insoluble  in  water.  Two  parts  of 
white  of  egg  and  one  of  water  entirely  co- 
agulate when  duly  heated ;  equal  parts  remain, 
under  the  same  circumstances,  semi-fluid;  a 
mixture  of  one  part  of  white  of  egg  and  ten  of 
water  becomes  opaque,  but  is  not  coagulated  ; 
and  a  milkiness  is  perceptible  when  the  al- 
bumen only  forms  a  thousandth  part  of  the 
solution.*  Fresh-laid  eggs,  and  those  which 
have  been  oiled  upon  the  surface  do  not  per- 
fectly coagulate  when  put  into  boiling  water,  in 
consequence,  probably,  of  the  dilute  state  of 
the  albumen.  One  hundred  parts  of  the  fresh 
albumen  of  the  egg,  when  carefully  evaporated 
in  vacuo,  leave  a  residue  ==  fifteen  parts.  One 
hundred  parts  of  the  coagulated  white  of  a 
duck's  egg  (dried  in  vacuo  with  sulphuric 
acid)  leave  13.65  parts,  which,  steeped  in 
water,  acquires  its  original  appearance,  but  in 
four  days  only  took  up  68  of  water,  though  it 

had  lost  86. 35 .f 

When  albumen  is  made  part  of  the  voltaic 
circuit,  it  presents  appearances  dependent  upon 
the  power  used,  which,  when  considerable, 
excites  so  much  heat  as  to  coagulate  it;  but 
with  a  feeble  power  and  the  poles  sufficiently 
distant,  coagulation  ensues  most  plentifully  at 
the  negative  platinum  wire ;  a  coagulum  also 
forms  at  the  positive  wire,  where  acid  is  also 
sparingly  evolved.  These  phenomena  are  much 
interfered  with  by  the  evolution  of  gaseous 
matters  at  the  respective  poles,  which  occasion 
a  froth,  and  the  appearance  of  more  extensive 
coagulation  than  actually  occurs. 

When  coagulated  white  of  egg  is  boiled  for 
several  hours,  it  shrinks  up  and  becomes  har- 
dened, communicating  traces  of  animal  matter 
to  the  water.  Heated  by  high  pressure  steam 
in  a  copper  digester  to  400°,  it  blackens  the 
interior  of  the  vessel,  and  dissolves,  leaving 
a  small  residue  of  unaltered  albumen.  The 
solution  is  brown,  and  has  the  odour  of  boiled 
meat  (from  osmazome  ?).  This  action  deserves 
further  investigation.! 

White  of  egg  soon  runs  into  putrefaction, 
and  evolves  sulphuretted  hydrogen.  The  se- 
rum of  blood  kept  for  two  years  in  a  well- 
stopped  phial,  blackened  its  interior,  and  be- 
came a  stinking,  pale,  yellow  liquid,  still  co- 
agulable  by  heat,  and  containing  hydro-sul- 
phate, carbonate,  and  acetate  of  ammonia,  and 
a  fetid  volatile  matter :  a  portion  of  yellowish 
white  purulent-looking  matter,  containing  un- 
decomposed  albumen,  remained  at  the  bottom 
of  the  phial.  Coagulated  white  of  egg,  even 
under  water,  long  resists  putrefaction. 

*  Bostock,  Nicholson's  Journal,  vol.  xiv.  and 
Medico-Chirurgical  Transactions,  vol.  i.  and  11. 

t  Chevreul,  |Mem.  du  Museum  vn.  IbO.  Ann. 
de  Ch.  et  Ph.  xix.  46. 

|  Gmelin,  Handbuch  der  Theoretischen  Chemie, 
ii.  1053.  3rd  ed.  Frankfort,  1827. 


ALBUMEN. 


89 


One  hundred  parts  of  dried  white  of  egg, 
subjected  to  destructive  distillation,  yielded 
carbonic  acid,  carburetted  and  sulphuretted 
hydrogen,  prussic  acid,  carbonate  of  ammonia 
partly  in  solution  and  partly  sublimed,  stinking 
volatile  oil,  and  14.9  of  spongy  difficultly  com- 
bustible carbon,  which,  by  incineration,  left 
2.21  of  ash  composed  of  carbonate  of  soda, 
phosphate  of  soda,  and  phosphate  of  lime, 
(Hatchett.) 

Nitric  acid,  dropped  into  a  solution  of  albu- 
men, forms  a  white,  flaky  precipitate,  which  is 
more  or  less  abundant  according  to  the  state 
of  dilution  of  the  solution,  and  which  is  soluble 
in  ammonia  and  potash.  When  coagulated 
white  of  egg  is  kept  for  some  weeks  in  very 
dilute  nitric  acid,  it  acquires  a  yellow  colour, 
and  if  digested  in  boiling  water  it  dissolves, 
and  has  acquired  the  properties  of  gelatine, 
and  is  precipitated  by  tan  and  muriate  of  tin. 
Hatchett.)*  Cold  nitric  acid  sp.  gr.  1.25, 
gradually  tinges  coagulable  white  of  egg  of  a 
yellow  colour,  dissolving  a  little  of  it,  and 
forming  malic  acid,  with  the  evolution  of  nitro- 
gen ;  its  surface  becomes  tallowy,  and  in 
twenty-four  hours  it  falls  into  a  pale  yellow 
powder,  which  is  acid  and  composed  of  nitric, 
nitrous,  and  malic  acids  with  albumen ;  when 
thoroughly  washed  with  water,  it  becomes  more 
neutral  and  of  an  orange  colour,  still  reddening 
litmus,  and  remaining  insoluble  in  water,  but 
soluble  in  caustic  potash  .f  When  coagulated 
white  of  egg  is  digested  in  hot  nitric  acid, 
nitrogen,  nitrous  gas,  carbonic  acid,  and  prussic 
acid  are  formed,  and  a  dark  yellow  solution 
obtained,  which  is  precipitated  by  the  addition 
of  water  and  ammonia,  and  which  contains 
malic  and  oxalic  acids,  bitter  matter,  and  fat. 
(Hatchett.)J 

Sulphuric  acid  is  a  less  powerful  precipitant 
of  albumen  than  nitric  acid.  Dilute  sulphuric 
acid  dropped  into  an  aqueous  solution  of 
albumen  occasions  a  precipitate  which  is  so- 
luble in  excess  of  acid ;  ferrocyanate  of  po- 
tassa  throws  it  down.  When  coagulated  albu- 
men is  digested  in  sulphuric  acid,  very  slightly 
diluted,  it  yields  a  deep  crimson  solution.§  Coa- 
gulated serum  digested  in  sulphuric  acid  diluted 
with  six  parts  of  water,  converts  it  into  acid 
sulphate  of  albumen,  which,  when  edulcorated 
with  cold  water,  becomes  more  neutral,  and 
is  soluble  in  warm  water,  forming  a  gelatinous 
solution,  which  is  precipitated  by  sulphuric, 
muriatic,  and  nitric  acids,  and  by  the  alkalies. 
(Berzelius.)H  Coagulated  white  of  egg  digested 
in  hot  sulphuric  acid  becomes  carbonized 
without  forming  artificial  tan.  (Hatchett.) 

When  a  solution  of  recently  fused  phosphoric 
acid  (pyro-phosphoric  acid)  is  added  to  solution 

*  Phil.  Trans.  1799. 

t  Berzelius  Lehrbuch  der  Thier.  Chemie,  p.  38. 
Wbhler's  Translation.  Dresden,  1831. 

J  Phil.  Trans.  1799. 

§  According  to  Raspail,  when  sugar  is  previously 
dissolved  in  the  sulphuric  acid,  the  albumen  is  co- 
loured purple,  which  is  deeper  in  proportion  as  the 
acid  and  sugar  are  in  greater  quantity. 

U  Lehrbuch  der  Thier.  Chemie. 


of  albumen,  it  occasions  an  abundant  pre- 
cipitate :  the  acid  gradually  loses  this  property, 
and  again  acquires  it  by  fusion  and  ignition. 
(Berzelius.) 

Muriatic  acid  occasions  a  precipitate  in  al- 
buminous solutions,  and  entirely  throws  down 
the  albumen  when  aided  by  heat;  but  the 
precipitate  is  soluble  in  excess  of  acid,  and 
in  ammonia  and  potassa.  A  muriated  albu- 
men may  be  formed  in  the  same  way  as  the 
sulphate.  (Berzelius.)  Coagulated  egg-albu- 
men digested  in  muriatic  acid  gradually  ac- 
quires a  purple  colour.  (Hatchett.)  Albumen 
which  has  been  precipitated  by  muriatic  acid, 
often  becomes  reddish  when  collected  and  ex- 
posed upon  a  filter. 

When  coagulated  seralbumen  is  digested 
in  acetic  acid,  it  becomes  soft  and  transparent, 
and,  aided  by  a  gentle  heat,  dissolves  with  the 
evolution  of  a  little  nitrogen.  This  solution 
is  precipitated  by  the  alkalies,  but  a  slight  excess 
again  renders  it  clear :  it  is  also  precipitated  by 
sulphuric,  nitric,  and  muriatic  acids,  and  by 
ferrocyanate  of  potassa.  When  this  acetic  so- 
lution of  albumen  is  evaporated,  it  leaves  a 
transparent  sour  residue,  soluble  in  warm  water 
acidulated  by  acetic  acid.  (Berzelius.) 

Albumen  is  slowly  soluble  in  liquid  ammo- 
nia. In  solution  of  potassa  it  becomes  gelati- 
nous, and  yields  a  pale  yellow  green  solution, 
precipitable  by  acids  and  alcohol,  and  by  acetic 
acid.  Heated  in  liquid  potassa,  albumen 
evolves  ammonia. 

Alcohol  and  ether  coagulate  ovalbumen,  but 
pure  ether  (free  from  alcohol)  does  not  co- 
agulate seralbumen.  (Gmelin.)  When  serum 
is  shaken  with  ether,  it  soon  separates  upon 
the  surface,  holding  fatty  matter  in  solution. 
(Gmelin.)  Coagulated  serum  digested  in  al- 
cohol or  ether  yields  a  solution  of  fatty 
matter. 

Coagulated  ovalbumen,  when  long  boiled  in 
water,  becomes  bulky  and  falls  into  pieces,  and 
a  small  portion  is  dissolved :  the  filtered  so- 
lution, evaporated  at  212°,  leaves  a  pale  brown 
film,  and  is  alkaline ;  it  is  rendered  turbid  by 
mineral  acids,  acetic  acid,  and  tincture  of 
galls,  and  by  many  metallic  salts. 

When  albumen  which  has  been  cautiously 
dried  at  a  low  temperature  (without  coagula- 
tion) is  triturated  with  four  parts  of  water, 
it  yields  a  solution  resembling  fresh  al- 
bumen. 

A  solution  of  the  white  of  an  egg  in  a  pint 
of  water  occasions  no  precipitate  in  lime,  bary- 
tic  or  strontia  water,  nor  in  solution  of  sulphate 
of  lime.  Some  of  the  neutral  salts  render 
it  more  or  less  turbid,  and  it  is  copiously 
precipitated  by  solution  of  alum.  Nitrate, 
acetate,  and  subacetate  of  lead  are  precipitated 
by  albuminous  solutions.  One  part  of  fresh 
ovalbumen  in  2000  of  water,  or  one  of  dried 
albumen  in  10,000  of  water  is  rendered  turbid 
by  subacetate  of  lead.  A  four-hundredth  part 
of  liquid,  or  a  two  thousandth  of  solid  albumen 
is  precipitable  by  corrosive  sublimate.  (Bos- 
tock.)  The  precipitate  is  blackened  by  potassa, 
and  is  probably  a  compound  of  muriate  ofalbu- 


90 


AMPHIBIA. 


men  and  calomel.  Nitrate  of  silver,  muriate 
of  gold ,  and  of  platinum ,  also  precipitate  album  i- 
nous  solutions.  These  precipitates  are  mostly 
triple  compounds  of  acid,  albumen,  and  oxide, 
and  several  of  them  are  redissoluble  in  excess 
of  liquid  albumen. 

Albumen  is  precipitated  by  tannin  in  the 
form  of  a  yellow  viscid  combination.  Water, 
holding  a  thousandth  part  of  solid  or  a  two- 
hundredth  of  liquid  ovalbumen,  becomes  tur- 
bid after  some  hours  by  the  addition  of  a 
solution  of  galls  containing  2.5  per  cent,  of 
solid  matter.  (Bostock.) 

The  above  are  the  principal  chemical  pro- 
perties of  liquid  and  solid  albumen  as  obtained 
from  the  egg  and  from  serum  of  blood  ;  several 
of  their  modifications  will  be  noticed  under 
other  heads,  such  as  FIBRIN E,  MILK,  BILE, 
&c. 

The  cause  of  the  coagulation  of  albumen  is,  in 
many  cases,  obscure  and  even  inexplicable.  It  ap- 
pears possible  that  the  acids  by  which  it  is  co- 
agulated enter  into  combination  with  it  so  as  to 
form  insoluble  compounds;  the  same  change  pro- 
bably happens  with  certain  metallic  salts,  and 
with  tan ;  its  coagulation  by  alcohol  has  been 
ascribed  to  the  abstraction  of  water.  Having 
remarked  the  copious  coagulation  of  albumen 
at  the  electro-negative  pole  in  the  voltaic  cir- 
cuit, I  was  induced  to  ascribe  the  fluidity 
of  albumen  to  combined  soda,  the  evolution 
of  which  seemed  to  cause  its  solidification,  and 
it  appeared  possible  that  the  acids  and  even 
alcohol  might  also  occasion  coagulation  by  the 
abstraction  of  soda ;  and  that  its  more  enigma- 
tical coagulation  by  heat  only,  might  be  as- 
scribed  to  the  transfer  of  soda  from  the  albu- 
men to  the  water.  It  has  been  objected  to 
this  statement  that  the  addition  of  alcali  to 
coagulated  albumen  does  not  reproduce  liquid 
albumen,  and  that  acetic  acid  causes  no  co- 
agulation ;  but  when  albumen  is  once  coagu- 
lated, its  properties  are  essentially  modified, 
and  acetic  acid,  or  even  acetate  of  soda  appear 
to  form  soluble  compounds  with  it.  (Gmelin.) 
Dr.  Turner*  supposes  that  albumen  combines 
directly  with  water  at  the  moment  of  being 
secreted,  at  a  time  when  its  particles  are  in 
a  state  of  minute  division  ;  but  as  its  affinity  for 
that  liquid  is  very  feeble,  the  compound  is 
decomposed  by  slight  causes,  and  the  albumen 
thereby  rendered  quite  insoluble.  The  or- 
ganization of  albumen  may  certainly  be  con- 
cerned in  its  singular  properties  with  respect  to 
many  coagulants  :  there  are  several  albuminous 
fluids,  which  we  shall  hereafter  refer  to,  which 
contain  globules  resembling  thosexof  the  blood. 
In  the  voltaic  coagulation  of  albumen,  that 
which  separates  at  the  positive  pole  contains 
globules,  which,  under  the  microscope,  resem- 
ble the  blood-globules  deprived  of  their  co- 
louring matter.f 

The  readiest  tests  of  the  presence  of  albumen 
in  fluids  are  its  coagulation  by  heat,  alcohol, 


*  Elements  of  Chemistry,  4th  ed.  868. 
t  Prevost  et  Dumas,  Ann.  de  Chimie  et  Physique 
xxiii.52. 


and  acids;  when  it  is  too  dilute  for  such 
detection,  it  may  be  subjected  to  voltaic  elec- 
tricity, or  tested  by  corrosive  sublimate,  or 
by  ferrocyanate  of  potassa;  the  alcali  should, 
in  the  latter  case,  be  previously  neutralized 
by  acetic  acid.  It  would  appear,  from  Orfila's 
experiments,  that  white  of  egg  is  an  antidote 
to  the  effects  of  corrosive  sublimate  when  taken 
into  the  stomach,  and  that,  if  administered  in 
sufficient  quantity  immediately  after  the  recep- 
tion of  the  poison,  it  prevents  the  progress 
of  the  symptoms.  The  white  of  one  egg 
appeared  sufficient  to  render  four  grains  of  the 
poison  ineffective. 

The  readiness  with  which  some  metallic 
oxides  are  received  into  the  system  may  per- 
haps be  ascribed  to  their  affinity  for  albumen, 
with  which  some  of  them  form  compounds  not 
easily  decomposable,  and  in  which  the  metallic 
oxide  cannot  be  detected  by  the  usual  tests, 
till  they  have  been  subjected  to  heat  sufficient 
to  decompose  the  organic  matter.  Mercury 
and  silver  are  thus,  in  certain  cases,  detected  in 
the  secretions  and  excretions. 

(W.  T.  Brande.) 


AMPHIBIA.—  (A^pK,  utrinque,  £to$,  vita. 
Fr.  Amphibies.  Germ.  Amphibien.  Ital. 
Amphibie.)  A  class  of  vertebrated  animals, 
hitherto  almost  universally  considered  as  an 
order  of  REPTILIA,  constituting  the  Batrachia 
of  the  later  erpetologists.  To  the  retention 
of  the  latter  appellation,  as  derived  from  the 
Greek  name  of  a  single  form  of  the  group, 
and  as  bearing  no  reference  to  any  character 
either  of  structure  or  of  habit,  there  is  an 
obvious  objection.  The  term  Amphibia  is 
therefore  here  adopted,  as  designating  one  of 
the  most  striking  peculiarities  of  the  class; 
namely,  the  change  which  takes  place  at  an 
epoch  of  their  life,  more  or  less  advanced, 
from  an  aquatic  respiration  by  branchise  to  an 
atmospheric  respiration  by  true  lungs,  and 
an  equivalent  and  consequent  alteration  in 
their  general  structure  and  mode  of  life. 

The  Amphibia  may  be  characterized  as 
"  vertebrated  animals,  with  cold  blood,  naked 
skin,  oviparous  reproduction,  and  most  of  them 
undergoing  a  metamorphosis  or  change  of  con- 
dition, having  relation  to  a  transition  from  an 
aquatic  to  an  atmospheric  medium  of  respi- 
ration." 

These  characters,  by  many  of  which  the  am- 
phibia are  distinguished  from  the  reptilia,  are 
sufficiently  determinate  and  important  to  justify 
our  considering  them  as  a  distinct  class,  ac- 
cording to  the  generally  received  principles  of 
zoological  arrangement  ;  notwithstanding  most 
even  of  the  modern  writers  on  the  subject  have 
retained  them  as  merely  an  order  of  reptilia. 
But  it  will  also  be  seen  that  if  in  the  adult  state 
they  approach  the  reptilia  in  many  points  of 
their  general  structure,  their  organization,  during 
the  early  and  imperfect  condition  of  the  tad- 
pole, partakes  no  less  of  that  of  fishes.  As 
an  osculant  or  intermediate  form,  connecting 
two  others  of  higher  typical  importance,  it  may 
be,  certainly  of  greater  extent,  and  consisting 


AMPHIBIA. 


91 


of  groups  having  more  striking  distinctive  cha- 
racters, there  is  not,  perhaps,  a  more  interesting 
and  satisfactory  instance  in  the  whole  range  of 
the  animal  creation  than  is  afforded  us  in  the 
class  of  amphibia :  a  circumstance  which  can 
only  be  fully  appreciated  by  following  out  the 
structure  of  each  system  of  organs,  first  as  it 
exists  temporarily  in  the  tadpole,  and  ultimately 
in  its  permanent  condition  in  the  perfect  animal. 

The  class  has  been  variously  divided  into 
groups  according  to  the  different  views  of  the 
naturalists  by  whom  they  have  been  arranged. 
The  division  adopted  by  many  zoologists  of 
the  present  day,  according  to  the  mere  presence 
or  absence  of  the  tail  in  the  perfect  state,  is 
not  only  liable  to  the  objections  which  belong 
to  all  merely  dichotomous  arrangements,  but 
appears  to  be  far  less  natural  and  less  consistent 
with  the  physiological  characters  of  the  groups 
than  that  which  may  be  derived  from  the 
absence  or  presence  and  the  duration  of  the 
branchiae.  Thus  the  frogs  and  toads,  which 
in  the  adult  state  have  not  the  vestige  of  a  tail, 
and  the  salamanders  and  tritons,  which  retain 
that  organ  through  life,  all  agree  in  the  early 
possession  of  branchioa,  which  are  subsequently 
lost  and  replaced  by  true  lungs,  and  in  un- 
dergoing consequently  a  total  change  in  the 
medium  of  their  respiration ;  whilst  the  pro- 
teus  and  the  siren  retain  their  branchiae,  with 
lungs,  (rudimentary  at  least,)  and  probably 
throughout  life  possess  synchronously  the  two- 
fold function  of  aquatic  and  atmospheric  re- 
spiration. The  amphiuma  and  menopoma  have 
not  as  yet  been  observed  to  possess  branchiae 
at  any  period  of  their  existence,  though  further 
observations  are  necessary  to  warrant  the  con- 
clusion of  an  absolute  non-existence  of  a  meta- 
morphosis in  these  genera. 

It  appears  to  me  that  no  one  arrangement 
hitherto  given  sufficiently  distinguishes  the 
different  forms  ;  and  I  venture  to  propose  the 
following  modifications  as  more  consistent  with 
the  diversities  of  structure  in  the  different 
groups. 

Class  AMPHIBIA. 

Order  1. — AMPHIPNEURTA. 

Body  elongate,  formed  for  swimming.  Feet 
either  four,  or  two  anterior  only.  Tail  com- 
pressed, persistent.  Respiration  aquatic  by 
means  of  branchiae,  throughout  life,  co-existing 
with  rudimentary  lungs.  Branchiae  external, 
persistent.  Eyes  with  palpebrae. 

Genera,  Proteus,  Siredon,  Menobranchus, 
Siren,  Pseudobranchus. 

Order  2. — ANOURA. 

Body  short  and  broad.  Feet  during  the  tad- 
pole state  wanting ;  afterwards  four,  the  hinder 
ones  long  and  formed  for  leaping.  Tail  before 
the  metamorphosis,  long,  compressed ;  after- 
wards totally  wanting.  Ribs  wanting.  Ver- 
tebrae few  and  anchylosed.  Tympanum  open. 
Respiration  at  first  aquatic  by  branchiae  ;  after- 
wards atmospheric  by  lungs.  Branchiae  at  first 
external,  but  withdrawn  within  the  chest  before 


the  metamorphosis.    Impregnation  effected  ex- 
ternally during  the  passage  of  the  ova. 

Genera,  Rana,  Hyla,  Ceratophrys,  Bufo, 
Rhinella,  Otilop/ta,  Ductylethra,  Bombinator, 
Breviceps. 

Order  3. — URODELA. 

Body  long,  slender.  Feet  always  four.  Tail 
long,  persistent.  Ribs  very  short.  Respi- 
ration at  first  aquatic  by  external  branchiae, 
afterwards  atmospheric  by  cellular  lungs.  Ver- 
tebrae numerous  and  moveable.  Tympanum 
concealed.  Impregnation  internal. 

Genera,  Salamandrina,  Salamandra,  Molge. 

Order  4. — ABRANCHIA. 

Body  long,  formed  for  swimming.  Feet  four. 
Cranium  solid.  Tail  compressed.  Respi- 
ration by  means  of  lungs  only:  branchiae  none. 
No  metamorphosis  known. 

Genera,  Menopoma,  Amphiuma. 

Order  5. — APOD  A. 

Body  elongate,  slender,  anguiform.  Feet 
none.  Tail  very  short,  almost  wanting.  Lungs 
one  larger  than  the  other.  (The  existence  of 
branchiae  at  any  period  of  life  unknown.)  Ribs 
very  short.  Sternum  wanting.  Ears  concealed. 
Impregnation  unknown,  probably  internal. 

Genus,  Cacilia. 

I.  Osteology. — The  changes  which  take  place 
in  the  habits  and  formation  of  these  animals, 
in  their  passage  from  the  tadpole  or  pisciform 
state  to  their  adult  and  permanent  condition, 
are  not  confined  to  any  one  system  of  organs 
or  of  functions.  The  skeleton,  the  organs  of 
motion,  of  sensation,and  of  digestion  are  not  less 
the  subject  of  these  changes  than  those  of 
respiration  and  circulation :  it  will,  therefore, 
be  necessary,  in  treating  of  each  system  of 
organs,  to  describe  not  merely  their  structure 
in  the  perfect  state,  but  the  less  advanced 
grade  of  organization  from  which  they  emerge 
in  passing  from  the  condition  of  a  fish  to  that 
of  a  reptile. 

In  the  adult  state,  however,  they  are  found 
to  vary  considerably  in  the  form  and  composi- 
tion of  the  skeleton,  according  to  their  habits, 
and  to  the  existence  or  absence  of  a  tail.  The 
principle  of  compensation,  or,  in  other  words, 
the  extreme  developement  of  one  set  of  organs 
at  the  expense  of  another,  which  is  so  often 
seen  to  take  place  in  every  form  of  animals, 
is  here  strikingly  illustrated.  In  the  frogs, 
whose  movements  on  land,  from  their  feeding 
chiefly  on  terrestrial  prey,  are  necessarily  ex- 
tensive, we  find  the  hinder  legs  developed  to 
an  extraordinary  degree,  for  the  purpose  of 
enabling  them  to  take  enormous  leaps,  by 
which  they  not  only  seek  or  pursue  their  prey 
at  a  distance  from  the  water,  but  rapidly 
escape  from  danger,  and  rapidly  regain  their 
place  of  refuge  in  the  nearest  pond  or  rivulet. 
As  it  is  evident  that  a  long  tail  and  a  generally 
elongated  body,  with  a  flexible  spine,  would 
Jbe  not  only  useless  but  inconsistent  with  these 
habits,  we  find  these  animals  absolutely  tail- 


92 


AMPHIBIA. 


less,  the  body  contracted  longitudinally  into 
as  short  a  space  as  possible,  the  vertebrae  very 
few,  and  anchylosed  or  soldered  together  into 
a  single  immoveable  piece,  and  wholly  devoid 
of  ribs. 

On  comparing  with  this  formation,  on  the 
other  hand,  the  extensive  developement  of 
the  tail,  the  long  flexible  body,  and  gracile 
form  of  the  newts  or  aquatic  salamanders, 
and  reflecting  upon  the  obvious  object  of  this 
structure  in  facilitating  their  motions  in  the 
water,  we  should  hardly  be  prepared  to  find 
that  the  extraordinary  extension  of  the  hinder 
extremities  in  the  frogs,  the  primary  object  of 
which  is  to  afford  the  great  powers  of  leaping 
just  alluded  to,  is  made  subservient  also  to 
their  aquatic  life,  by  enabling  them  to  swim 
with  great  facility,  aided  by  a  web  of  skin 
extending  between  the  toes  of  the  hinder 
feet. 

Now  as  we  shall  hereafter  see,  when  treating 
on  the  respiration  of  these  animals,  that  the 
occasional  presence  of  water,  and  its  applica- 
tion to  the  surface  of  the  skin,  is  equally 
essential  to  the  well-being  of  both  these 
forms,  it  is  very  interesting  to  observe  how 
admirably  this  peculiarity  in  the  general  re- 
quirements is  provided  for  by  the  very  different, 
and  even  opposite,  construction  of  their  form 
and  limbs,  which  their  individual  habits  of  life 
demand. 

But  to  return  to  the  detailed  anatomy  of  the 
skeleton.  On  examining  the  general  texture 
of  the  bones  in  this  class,  there  is  an  obvious 
advance  towards  the  firm  calcareous  substance 
of  those  of  the  higher  forms  of  vertebrated 
animals  when  compared  with  the  bones  of 
fishes,  they  being  more  compact,  and  less  tran- 
sparent and  flexible  than  in  the  latter  animals. 
The  cranial  bones,  though  they  retain  to  a 
certain  extent  the  character  of  those  of  fishes, 
in  the  permanent  disunion  of  the  different 
centres  of  ossification,  at  least  in  many  in- 
stances, yet  they  do  not  overlap  each  other, 
as  in  that  class,  but,  on  the  contrary,  remain 
with  their  margins  at  least  in  contact,  and  in 
many  cases  actually  united,  though  not  by 
true  sutures.  The  elements  of  which  the 
cranium  is  essentially  composed,  and  which 
in  a  higher  grade  of  organization  are  found 
consolidated,  are  here  still  exhibited  as  distinct 
pieces ;  a  state  of  things  which  is  strikingly 
imitated  in  the  progress  of  the  development 
of  these  parts  in  the  highest  classes  during 
their  growth.  It  is  also  to  be  observed  that  the 
bones  of  the  face  are  more  closely  united  to 
those  of  the  cranium  and  to  each  other  in 
the  higher  than  in  the  lower  forms  of  the  class, 
exhibiting  distinct  and  obvious  links  in  the 
development  of  these  parts,  which  we  see  so 
beautifully  and  gradually  perfected  in  the  as- 
cending series  from  fishes  up  to  man. 

The  following  enumeration  of  the  separate 
cranial  bones  of  the  amphibia,  as  existing  in 
the  menopoma  alleganiensis,  the  gigantic  sala- 
mander of  America,  will  illustrate  the  general 
relations  of  the  distinct  centres  of  ossification, 
here  remaining  permanently  detached. 


Fig.  14. 


In  figs.  14  and  15  the  different  elements 
are  thus  designated: — a.  the  frontal;  b.  the 
exterior  frontal ;  c.  the  parietal ;  d.  the  nasal ; 


e.  the  occipital ;  f.  the  pterygoid ;  g.  the 
tympanic ;  h.  the  jugal ;  i.  the  superior 
maxillary;  k.  the  intermaxillary;  /.  the  vomer; 
m.  the  sphenoid ;  n.  corresponding  to  the  or- 
bitary  processes  or  alae  of  the  sphenoid.  In 
the  frog  and  most  others  the  palatine  bones 
are  distinct.  We  here  find  that  the  separate 
portions  or  elements  which  in  this  class  are 
permanently  detached,  correspond  almost  ex- 
actly with  the  number  found  in  the  cranium 
of  fishes. 

It  will  be  observed  by  a  reference  to  the 
figures,  that  the  intermaxillary  bones — and  this 
is  more  or  less  the  case  in  all  the  amphibia — 
are  much  developed  transversely,  as  in  the 
fishes,  an  affinity  which  has  been  already  so 
much  insisted  on,  and  which  is  borne  out  by 
the  condition  of  all  the  other  parts  of  the  cra- 
nium. The  lateral  extension  of  the  upper  and 
lower  maxillary  bones,  for  instance,  as  well  as 
of  the  tympanic  and  jugal,  expands  the  general 
form  of  the  skull,  without  involving  any  ex- 
pansion of  the  cavity  of  the  cranium,  which  is 
restricted  to  a  small,  central,  elongated  space. 
The  latter  bones  also  terminate  in  a  condyle, 
which  is  received  into  a  shallow  glenoid  cavity 
of  the  lower  jaw,  a  peculiarity  which  offers  a 


AMPHIBIA. 


93 


still  further  illustration  of  the  proximity  of  this 
class  to  the  fishes.  The  lower  jaw  consists  of 
three  distinct  pieces  on  each  side,  an  anterior, 
a  lateral,  and  a  posterior  or  articular  portion. 
The  anterior  bone  supports  the  teeth  in  those 
genera  which  have  teeth  in  the  lower  jaw,  and 
unites  with  its  fellow  at  the  symphysis.  In 
frogs  the  lower  jaw  is  devoid  of  teeth,  but  they 
are  found  in  the  upper  jaw,  bordering  the  in- 
termaxillary and  the  maxillary  bones ;  and  the 
vomers  are  also  furnished,  each  with  a  trans- 
verse row  of  teeth ;  but  in  the  salamander,  the 
menopoma,  the  proteus,  and  others,  they  are 
found  occupying  the  margin  of  the  lower  jaw. 
In  the  toads  there  are  no  teeth  in  the  lower  jaw, 
but  the  edge  of  the  jaw-bone  is  serrated.  The 
second  bone  of  the  inferior  maxilla  occupies 
the  side,  and  is  larger  even  than  the  former.  It 
has  at  the  posterior  part  a  coronoid  process, 
behind  and  within  which  is  placed  the  third 
bone,  which  forms  the  medium  of  articulation 
with  the  cranium. 

It  is  to  the  os  hyoides  that  the  principal  interest 
attaches  in  the  present  class,  as  it  is  that  bone 
which  undergoes  the  most  remarkable  changes 
in  its  form  and  relations  during  their  transforma- 
tion, passing  from  the  office  of  supporting  the 
branchial  organs  into  a  true  os  hyoides,  and 
thus  offering,  as  Cuvier  has  beautifully  shewn, 
an  elucidation  of  the  true  nature  of  this  ap- 
paratus in  fishes.  As  this  bone,  however,  has 
a  direct  relation  with  the  respiratory  functions, 
I  shall  explain  these  changes  while  treating  on 
that  part  of  the  subject. 

The  spinal  column  varies  exceedingly  in  the 
different  forms  of  the  amphibia.  In  the  highest 
form  the  vertebrae  are  fewer  than  are  found  in 
any  other  animals.  In  the  common  frog 

Fig.  16. 


there  are  but  nine,  and  in  the  pipa  only  eight. 
Of  the  nine  vertebrae  in  the  frog,  the  first,  the 
atlas,  a,  has  no  transverse  processes  ;  there  are 
two  articular  surfaces  situated  anteriorly,  by 
which  it  is  articulated  to  the  two  occipital 
condyles.  In  the  seven  following  vertebrae  the 
anterior  articular  surfaces  of  the  bodies  are 
concave,  and  the  posterior  convex.  This  con- 
vex tubercle,  which  enters  the  concavity  of  the 


next  vertebra,  consists  of  the  intervertebral  car- 
tilage converted  into  bone.  In  the  tadpole 
condition  of  the  animal  (and  this  remains  per- 
manently the  case  in  the  perenni-branchial 
forms,  as  the  menobranchus,  the  proteus,  &c.) 
this  intervertebral  substance  retains  the  soft  con- 
sistence which  characterises  it  in  fishes ;  and, 
as  in  that  class,  it  is  contained  in  the  circum- 
scribed cavity  formed  by  the  cup-like  hollows 
of  the  two  articular  surfaces  of  contiguous 
vertebrae.  The  elongated  fish-like  form  of 
those  amphibia  which  retain  their  branchiae 
throughout  life,  requires  that  this  structure 
should  also  be  permanent ;  and  we  have  thus 
another  beautiful  example  of  that  perfect  chain 
of  organisation  which  is  manifested  by  this 
class  of  animals,  from  the  fish  upwards  to  the 
reptilia. 

The  vertebrae  of  the  adult  frog  have  long 
transverse  processes  (fig.  16,  6),  but  are  wholly 
destitute  of  ribs — a  class  of  bones  which 
would  be  utterly  useless  in  the  particular 
modes  of  locomotion  to  which  these  animals  are 
restricted,  and  the  absence  of  which  implies 
a  peculiarity  in  the  act  of  respiration,  which 
will  be  described  hereafter.  The  spinous  pro- 
cesses are  very  short ;  the  articular  are  oblique, 
the  posterior  of  each  being  placed  above  the 
anterior  of  the  following  one. 

The  last  or  sacral  vertebra  has  large  transverse 
processes  (fig.  16,  c)  directed  a  little  back- 
wards, to  which  the  ilia  (fig.  16,  d)  are  at- 
tached; and  to  the  body  of  this  vertebra  is 
united  by  two  tubercles,  a  long  single  bone, 
extending  backwards  to  above  the  anus.  This 
bone  (fig.  16,  e)  is  considered  by  Cuvier  as  a 
second  sacral  vertebra ;  but  by  Schultze, 
Altena,  Dr.  Grant,  and  others,  it  is  regarded 
as  the  coccyx.  The  vertebral  canal  occupies 
the  anterior  third  of  a  carina  or  crest,  which 
runs  along  the  upper  surface  of  this  bone, 
diminishing  gradually  in  its  course  until  it 
wholly  disappears. 

The  spinal  column  in  the  other  orders  of 
the  class  differs  in  a  remarkable  degree  from 
that  which  has  been  just  described.  In  the 
salamander  there  are  thirteen  dorsal,  two  sacral, 
and  about  twenty-five  caudal  vertebrae,  which  in 
the  genus  molge  or  newt  are  increased  to  upwards 
of  thirty.  In  these  the  anterior  surface  of  the 
body  is  convex,  and  the  posterior  concave,  a 
contrary  arrangement  to  that  which  occurs  in 
frog.  The  transverse  processes  are  directed 
a  little  backwards,  each,  excepting  the  atlas, 
supporting  a  small  rib,  which  is  scarcely  curved. 
The  menopoma  has  a  similar  arrangement.  In 
the  siren  are  found  forty-three  vertebrae  in  the 
trunk,  and  forty-four  or  more  in  the  tail.  They 
all  retain  in  a  great  measure  the  form  of  those 
of  fishes  and  of  the  tadpole  of  the  higher  orders 
of  this  class,  particularly  in  the  existence  of  the 
intervertebral  cavity  or  double  cone,  formed 
by  the  apposition  of  two  hollowed  surfaces  of 
their  bodies,  and  filled  by  a  semi-cartilaginous 
mass  or  intervertebral  substance.  Eight  only 
of  the  vertebrae,  commencing  with  the  second, 
bear  ribs,  which  are  extremely  small,  and  in 
fact  merely  rudimentary.  In  the  tail  the  trans- 


94 


AMPHIBIA. 


verse  processes  are  only  found  on  a  few  of  the 
most  anterior  vertebrae. 

The  spine  of  the  proteus  is  not  sufficiently 
different  from  that  of  the  siren  to  require  any 
particular  description. 

The  construction  of  the  members,  both  an- 
terior and  posterior,  especially  the  latter,  will 
be  found  to  be  arranged  on  very  different  plans, 
according  to  the  habits  and  requirements  of  the 
different  groups,  and  particularly  their  mode  of 
progression.  In  the  apoda,  as  the  ccecilia,  there 
are  not  even  the  rudiments  of  limbs.  In  the 
other  orders  they  exist  under  very  different 
degrees  of  development,  according  as  they  are 
constructed  for  leaping  and  swimming,  as  in 
the  frogs,  toads,  &c.,  or  for  creeping,  as  in  the 
salamanders;  or  they  are  rudimentary,  and 
without  any  very  apparent  use,  as  in  the  am- 
phiuma.  It  will  be  necessary  to  give  a  cursory 
description  of  these  forms. 

Of  the  anterior  extremity  in  the  anoura. — 
The  shoulder  of  the  frog  (fig.  16,  f.  Jig.  17.) 
consists  of  the  scapula,  the  clavicle,  and  the 
coracoid  bone,  which  all  combine  to  form  the 
glenoid  cavity  for  the  head  of  the  humerus. 
The  scapula  is  composed  of  two  very  distinct 
portions.  The  upper,  (Jig.  17,  a,)  which  is 


Fig.  17. 


permanently  cartilaginous,  at  least  at  its  mar- 
gin, is  articulated  moveably  to  the  inferior  and 
more  solidly  ossified  piece,  (Jig.  17,  b,)  at  the 
inferior  and  posterior  part  of  which  is  the  arti- 
cular surface  forming  its  portion  of  the  glenoid 
cavity,  immediately  anterior  to  which  it  is  at- 
tached to  the  clavicle.  (Jig.  17,  c.)  This 
bone  is  slender  and  straight,  and  is  connected 
beneath  with  its  fellow  in  the  median  line. 
The  coracoid  bone  (fig.  17,  d)  is  considerably 
larger  than  the  clavicle,  and  is  also  connected 
with  its  fellow  by  its  broad  median  margin. 
The  sternum  consists  of  several  pieces,  ex- 
tending from  before  the  clavicles  to  some  dis- 
tance behind  the  coracoid  bones;  the  latter 
terminates  in  a  broad  xiphoid  cartilage.  These 
parts  differ  considerably  in  their  relative  pro- 
portions in  different  genera. 

The  arm  is  developed  in  a  very  inferior  de- 
gree compared  with  the  hinder  extremity.  The 
humerus  (fig.  17,  g)  is  short  and  thick,  having 
a  rounded  head,  received  into  the  glenoid  ca- 


vity of  the  shoulder-joint.  The  opposite  extre- 
mity forms  an  almost  globular  surface  for  its 
articulation  with  the  bone  of  the  fore-arm, 
which  is  still  shorter,  and  consists  of  the  radius 
and  ulna  united,  (fig.  17,  h,)  having  only  a 
slight  groove  to  show  their  line  of  union.  The 
carpal  bones  (Jig.  16,  i)  are  six  in  number, 
supporting  the  four  metacarpal  bones,  (fig.  16, 
k.)  The  index  and  middle  finger  have  each 
two  phalanges,  the  others  three.  The  index  is 
particularly  large  in  the  male.  The  thumb  is 
merely  rudimentary. 

The  posterior  extremity  is  greatly  developed 
in  the  frogs,  for  the  purpose  before  mentioned, 
of  enabling  them  to  take  long  leaps,  and  to 
swim  with  great  rapidity  and  energy.  The 
pelvis  consists  of  the  three  essential  bones  of 
this  part,  the  ilium,  ischium,  and  pubis  on 
each  side.  The  iliac  bones,  (fig-  16,  d,)  di- 
verging above,  are  moveably  articulated  with 
the  sacrum .  They  then  extend  backwards,  and 
form,  together  with  the  small  ischiatic  and  pubic 
bones,  (fig.  16, 19)  the  cotyloid  cavities  for  the 
reception  of  the  femur.  This  bone  (fig.  16,  m) 
is  nearly  twice  as  long  as  the  humerus,  cylin- 
drical, and  having  a  slight  double  curve. 
The  leg  consists,  like  the  fore-arm,  of  but  one 
bone,  the  tibia  and  fibula  being  anchylosed 
through  their  whole  length.  This  bone  (Jig. 16, 
n)  is  even  a  little  longer  than  the  femur.  It 
is  succeeded  by  two  bones  of  considerable 
length,  (Jig.  16,  o,)  having  very  much  the 
aspect  of  a  tibia  and  fibula,  but  which  must 
be  considered  as  bones  of  the  tarsus  greatly 
modified,  and  are  most  probably  the  os  calcis 
and  the  astragalus.  Between  these  elongated 
bones  and  the  metatarsal  are  four  small  tarsal 
bones.  The  metatarsal  bones  (Jig.  16,  p)  are 
much  elongated,  as  are  also  the  phalanges, 
(fig.  16,  q°)  for  the  purpose  of  forming  strong 
oars  or  paddles  with  the  intervention  of  a  broad 
web  of  integument.  The  inner  toe  is  consi- 
derably developed,  and  the  whole  structure  of 
the  foot  and  leg  thus  combines  to  furnish  a  pow- 
erful and  efficient  organ  of  progression. 

The  elongated  forms  of  the  aquatic  sala- 
mander, the  proteus,  the  siren,  &c.,  in  which 
the  vertebrae  are  developed  to  so  great  an  extent, 
present  the  opposite  extreme  in  the  structure  of 
their  limbs.  These  are  small,  feeble,  and  ap- 
pear as  it  were  abortions.  In  the  genus  triton 
and  in  the  salamandra,  which  possess  both  an- 
terior and  posterior  extremities,  they  differ  but 
little  in  their  general  form  and  development. 
The  bones  of  the  fore-arm  as  well  as  of  the  leg, 
instead  of  being  respectively  anchylosed  into 
a  single  piece,  as  in  the  frogs,  are  permanently 
separate,  consisting  of  a  distinct  ulna  and  radius 
in  the  former,  and  an  equally  distinct  tibia  and 
fibula  in  the  latter.  The  toes  are  four,  both 
before  and  behind;  they  are  short,  slender, 
and  of  slight  construction. 

This  imperfect  development  of  the  extremi- 
ties is,  however,  as  we  have  seen,  admirably 
compensated  by  the  extraordinary  extent  of  the 
spine  both  in  the  body  and  the  tail ;  and  while 
the  limbs  afford  but  very  imperfect  means  of 
progression  on  land,  the  structure  of  the  spine 


AMPHIBIA. 


is  admirably  adapted  to  the  purpose  of  swim- 
ming, which  is  performed  either  by  a  succes- 
sion of  curves,  as  in  the  amphiuma  and  the 
siren,  or  by  the  alternate  flexure  of  the  tail,  as 
in  the  tritons  and  the  menobranchus. 

Having  given  this  general  sketch  of  the  os- 
teology of  the  amphibia  in  the  adult  state,  it 
will  be  interesting  to  examine  the  structure  of 
the  skeleton  in  the  tadpole.     It  has  already 
been  observed  that  in  this  early  condition  of  its 
existence   the   animal   resembles  fishes  in   all 
the  most  remarkable  characters  of  its  organi- 
zation.    We  find  accordingly  that  the  limbs, 
which  are  at  first  scarcely  perceptible  by  the 
most   minute   examination,   become  gradually 
developed,    passing    through    a    rudimentary 
form   beneath  the  integuments,    from   which 
they  do  not  emerge  until  they  have  acquired 
considerable  size  and  a  very  defined  figure. 
The  hinder  legs  are  first  seen,  and  are  early 
employed  as  a  feeble  assistance  to  the  more 
effective  tail,    as   instruments   of  progression. 
The   tail  is  developed,    however,    to  a  great 
degree,  occupying  the  same  relative  size  and 
situation  as  it  is  found  to  do  in  fishes.     The 
coccygeal  vertebrae  are  numerous,  forming   a 
long   column,   not  ossified,    but  retaining  its 
cartilaginous  structure,  at  least  in  those  forms 
in  which  it  is  deciduous;  but  in  the  salamanders, 
the  tritons,  the  proteus,  and  all  others  of  the 
urodcht,  it  becomes  ossified  instead  of  being 
absorbed.     In  the  frog  and  other  anoura,  as 
the  permanent  organs   of  progression  acquire 
their  full  development,  the  tail  is   slowly  re- 
moved by  interstitial  absorption,  not  suddenly 
falling  off  as   some  have   supposed,  but  be- 
coming gradually   smaller  and   smaller   until 
it  wholly   disappears.     The  cranium   under- 
goes no  other  important  change  than  that  of 
the  gradual  ossification  and  expansion   of  its 
different  elements,  the  centres  of  ossification 
being  at  first  wholly  disunited  as   in  fishes, 
and  afterwards  assuming  the  more  consolidated 
structure    and    closer  approximation   to   each 
other,  by  which  they  approach  the  reptilia. 

II.  Muscular  system. — The  similarity  which 
has  been  already  shewn  to  exist  in  the  osseous 
system  of  fishes  and  of  the  tadpole  and  peren- 
nibranchiate  amphibia,  would  naturally  lead 
to  the  conclusion  that  a  corresponding  affinity 
would  be  found  in  the  muscular  apparatus. 
The  muscles  which  are  employed  for  progres- 
sion in  those  early  forms  of  vertebrated  beings, 
are  found  to  consist  of  oblique  layers,  abutting 
upon  a  median  line,  and  extending  along  the 
whole  length  of  the  tail  on  each  side.  A  similar 
general  direction  obtains  in  the  muscles  both  of 
the  trunk  and  tail  in  the  long-bodied  forms  of 
the  permanently  tailed  amphibia.  The  direction 
of  their  action  therefore  is  horizontal,  and  their 
progression  is  effected  by  the  alternate  action 
of  the  muscles  on  each  side.  These  oblique 
caudal  muscles  in  the  tadpole  of  the  tailless 
tribe,  become  absorbed  with  the  vertebrae  to 
which  they  are  attached,  as  the  animal  gradually 
assumes  its  permanent  form;  but  its  aquatic 
habits  are  still  provided  for  by  the  extraordinary 
magnitude  of  the  flexors  and  extensors  of  the 
thigh,  leg,  and  foot,  which  are  in  perfect  ac- 


cordance with  the  great  length  of  the  bones  of 
this  extremity,  which  has  been  described.    The 
muscles  which  form  this  important  apparatus 
of  motion  are  exactly  analogous  to  those  which 
are  so  peculiarly  developed  in  the  human  leg. 
Thus  the  large  glutei  extend  the  femur,  the 
rectus  and  triceps  extend  the  leg,  and  by  their 
united  and  sudden  action  forcibly  throw  the 
whole  limb  into  a  straight  position,  whilst  the 
gastrocnernii,  which  are  here  as  in  the  human 
subject  of  sufficient  size  to  form  a  considerable 
calf  of  the  leg,  enable  the  foot  with  the  wide 
expanse  of  its  toes,  connected  as  they  are  by  a 
tense  web,  to  strike  with  great  force  and  effect 
the  resisting  medium  in  which  they  live,  assisted 
by  the  flexors  of  the  toes,  which  are  called  into 
action  at  the  same  instant.     The  same  beau- 
tiful mechanism  is  no  less  adapted  for  the  pe- 
culiar nature  of  their  progression  on  land ;  by 
it  they  are  enabled  to  take  those  long  and  vigo- 
rous leaps  which  particularly  characterize  some 
of  the  genera  of  the  acaudate  family  of  this 
class.     It  is  obvious   that  the   same   sets   of 
muscles  must  be  developed  for  the  performance 
of  the  energetic  and  sudden  movements  above- 
mentioned  as  are  required  to  sustain  the  upright 
form  of  the  human  subject  in  its  erect  position, 
those,  namely,  which  extend  at  once  the  thigh 
upon  the  pelvis,  the  leg  upon  the  thigh,  and 
the  heel  upon  the  leg;  and  hence  arises  the 
remarkable  similarity  in  the  conformation  of 
the  leg  in  these  otherwise  remote  forms,  and 
hence  too  the  act  of  swimming  in  man  must 
be  a  tolerably  accurate  imitation  of  the  same 
effort  as  exhibited  by  the  frog. 

III.  Organs  of  digestion. — The  foregoing 
consideration  of  the  various  structures  of  the 
organs  appertaining  to  locomotion  would  pre- 
pare us  for  corresponding  differences  in  those 
belonging  to  this  important  office.  These 
variations,  however,  are  not  found  exactly  to 
follow  those  which  have  been  described  in  the 
former  class  of  organs.  The  tadpole  condition 
of  the  higher  amphibia  does  not  correspond 
in  the  nature  of  its  food,  nor  consequently  in 
the  structure  of  the  alimentary  canal,  with 
the  class  of  fishes,  nor  indeed  with  that  per- 
manent tadpole,  as  it  may  be  called,  the 
larviform  axoloth. 

The  teeth,  as  has  been  already  stated,  vary  in 
the  different  genera  not  so  much  in  their  size  and 
form  as  in  their  situation.  Thus  the  whole  of  the 
amphibia  have  teeth  in  the  palate;  the  sala- 
manders have  them  also  in  both  the  upper 
and  lower  jaws,  the  frogs  in  the  upper  only, 
and  the  toads  in  neither.  In  the  two  latter 
genera  the  palatine  teeth  are  placed  in  a  trans- 
verse line,  interrupted  in  the  middle.  In  the 
salamanders  they  form  two  parallel  lines,  con- 
taining not  less  than  thirty  on  each.  In  the 
menopoma  they  occupy  the  anterior  palatine 
margin  of  the  vomer,  forming  a  line  on  each 
side  parallel  with  the  maxillary  and  inter- 
maxillary teeth.  In  the  axoloth  they  are 
arranged  in  the  quincuncial  order,  and  are  nu- 
merous. But  the  most  remarkable  form  and 
arrangement  of  the  palatine  teeth  is  found  in 
the  siren,  in  which  they  have  the  quincuncial 
arrangement;  they  are  placed  on  two  small 


96 


AMPHIBIA. 


bony  plates  on  each  side,  probably  rudiments 
of  the  vomer  and  palatine  bones.  Each  of 
the  larger  has  six  or  seven  lines  of  teeth,  about 
twelve  on  each  line;  and  each  smaller  bone 
bears  four  ranges  of  five  or  six  teeth ;  making 
in  all  nearly  two  hundred  teeth  in  the  palate. 
Those  of  the  lower  jaw  in  this  animal  are 
placed  in  similar  order.  In  the  proteus  the 
teeth  nearly  resemble  those  of  the  salamander. 

The  maxillary  teeth  are  always  slender, 
sharp-pointed,  and  closely  -set.  The  frog  has 
about  forty  on  each  side  of  the  upper  jaw,  of 
which  eight  belong  to  the  intermaxillary  bone. 
The  salamander  has  about  sixtyabove  and  below. 

In  the  tadpole  state  of  the  frog  the  mouth 
is  very  small,  and,  instead  of  teeth,  is  occu- 
pied only  by  minute  horny  plates  of  just 
sufficient  consistence  to  abrade  the  soft  mixed 
food  which  it  finds  on  the  surface  of  animal 
or  vegetable  substances  in  the  water.  Its  sto- 
mach and  intestinal  canal  are  of  very  different 
form  from  that  which  they  afterwards  assume. 
The  intestine  is  of  nearly  equal  size  throughout 
its  whole  length.  It  is  very  long,  being  not 
less  than  ten  times  the  length  of  the  actual 
space  from  the  mouth  to  the  anus,  and  is  coiled 
up  in  a  circular  form,  occupying  the  greater 
part  of  the  abdominal  cavity.  The  canal,  as 
we  shall  presently  see,  changes  its  character 
materially  during  the  metamorphosis  of  the 
animal,  becoming  gradually  shorter  until  it  is 
not  a  quarter  of  the  length,  in  proportion  to 
the  size  of  the  animal,  which  it  exhibited  in 
its  earlier  condition. 

In  the  adult  amphibia  the  whole  alimentary 
canal  is  of  a  very  simple  character.  The 
oesophagus  is  wide  and  comparatively  short. 
The  stomach  single,  consisting  of  a  simple  sac, 
elongated  in  the  lengthened  forms  of  the  sala- 
mander, the  proteus,  and  other  aquatic  species. 
The  intestine  is  but  slightly  convoluted,  even 
in  the  short  tailless  family ;  and  there  is  com- 
paratively little  difference  in  the  diameter  of 
its  two  distinct  portions.  It  terminates,  as  in 
the  reptilia,  in  a  cloaca,  or  pouch,  which  also 
receives  the  openings  of  the  urinary  and  genital 
organs.  The  anus  in  the  toads  and  frogs  opens 
on  the  hinder  part  of  the  back  ;  in  the  other 
forms  it  is  situated  beneath  at  the  commence- 
ment of  the  tail,  as  in  the  reptilia. 

The  liver,  the  pancreas,  and  the  spleen  are 
found  in  the  whole  of  the  amphibia ;  and 
these  organs  are  observed,  in  the  elongated 
aquatic  forms,  to  assume  a  corresponding 
lengthened  shape.  The  liver  is  of  considerable 
size,  particularly  in  the  salamanders.  The 
gall-bladder  exists  in  all  cases,  varying,  how- 
ever, in  size  and  form  in  the  different  genera. 

IV.  Lymphatic  and  lacteal  system. — This 
system  is  highly  interesting  in  the  amphibia, 
on  account  of  its  extreme  development,  and 
of  its  presenting  several  important  and  remark- 
able peculiarities  in  its  structure. 

The  investigations  of  Professor  Muller  of 
Berlin  have  lately  brought  to  light  the  existence 
of  pulsating  cavities  in  the  course  of  the  lympha- 
tics, constituting  a  sort  of  ventricles  for  the  pro- 
pulsion of  their  fluids  towards  the  veins  into 
which  they  are  received.  In  the  frog  two  pairs  of 


these  little  pulsating  sacs  are  found  ;  at  the  pos- 
terior part  one  is  situated  on  each  side  of  the 
extremity  of  the  coccygeal  bone,  behind  the  hip- 
joint,  and  the  anterior  ones  under  the  posterior 
edge  of  the  scapula  by  the  transverse  process 
of  the  third  vertebra.  These  cavities  are  of 
considerable  size,  and  pulsate  with  some  degree 
of  regularity  :  the  pulsations,  however,  do  not 
coincide  with  those  of  the  heart,  nor  are  those 
on  the  one  side  always  synchronous  with 
those  on  the  other.  The  posterior  ones  convey 
the  lymph  received  from  the  legs  and  hinder 
parts  of  the  body  into  the  ischiatic  veins,  and 
the  anterior  pair,  into  which  the  absorbents 
of  the  arms  and  the  anterior  parts  of  the 
viscera,  &c.  open,  convey  this  fluid  into  the 
jugular  veins.  The  internal  structure  of  these 
sacs  is  cellular;  they  communicate  freely 
with  each  other  on  each  side  by  anastomosing 
vessels.  On  inflating  the  organ,  not  only  the 
lymphatic  vessels  are  inflated,  but  the  whole 
of  the  veins  also.  Dr.  Marshall  Hall  had 
previously  observed  a  somewhat  similar  pul- 
sating cavity  in  the  eel. 

These  lymphatic  ventricles  in  the  amphibia 
have  still  more  recently  received  further  exami- 
nation and  illustration  by  Professor  Panizza 
of  Pavia,  who  published  the  result  of  his 
researches  in  the  year  1833.*  Professor  Muller's 
discovery  was  published  in  the  previous  year 
in  the  Berlin  Annals. 

The  lymphatic  system  is  developed  to  an 
extraordinary  degree  in  the  frogs,  as  well  as 
in  several  other  genera  of  this  class,  its  vessels 
being  found  in  numbers  and  of  considerable 
size  immediately  under  the  skin. 

The  lacteals  ramify  upon  the  surface  of  the 
intestine  in  two  layers,  anastomosing  and 
forming  intricate  plexuses  on  the  mesentery, 
and  terminating  in  two  trunks,  or  thoracic 
ducts,  which  pass  forwards  one  on  each  side 
of  the  spinal  column. 

V.  Of  the  sanguiferous  system. — If  the 
changes,  so  frequently  alluded  to,  which  the 
animals  of  this  class  undergo  in  passing  from 
the  condition  of  a  fish  to  that  of  a  reptile,  have 
received  repeated  illustrations  in  the  considera- 
tion of  the  structure  of  the  skeleton,  of  the 
organs  of  motion,  and  of  those  of  digestion,  far 
more  interesting  and  important  are  those  which 
occur  in  the  character  of  the  circulation ;  in 
which  the  view  which  has  been  taken  of  the 
true  situation  of  the  amphibia  in  the  chain  of 
animal  development  receives  the  most  satis- 
factory proof.  Beginning  life  with  all  the 
essential  characters  of  the  fishes,  even  in  the 
functions  of  circulation  and  respiration,  pos- 
sessing the  single  branchial  heart  of  that  class, 
how  wonderful  and  beautiful  are  the  changes 
which  these  systems  of  organs  undergo,  as  the 
branchiae  become  obliterated  to  give  place  to 
pulmonic  cavities,  and  the  heart  at  the  same 
time  assumes  the  compound  character  and  form 
of  a  systemic  and  pulmonic  heart,  in  accordance 
with  the  change  in  the  respiratory  organs. 

The  newts,  or  water-salamanders,  afford  the 
most  satisfactory  opportunity  of  observing  these 

*  Sopra  il  sistema  linfatico  dei  rettili.  fol.  Pav. 
1833. 


AMPHIBIA. 


97 


changes,  as  the  branchiae  are  large  in  propor- 
tion, and  remain  external  during  the  whole 
period  of  their  existence ;  the  animal  also 
acquires  considerable  size  before  these  organs 
of  aquatic  respiration  are  lost.  The  heart  in 
the  early  stage  of  these  animals  consists  of  a 
systemic  auricle,  which  receives  the  whole  of 
the  blood  from  the  system  after  circulation,  and 
of  a  ventricle  which  propels  it  through  a  third 
cavity,  the  bulbus  arteriosus,  to  the  branchial 
arteries,  of  which  there  is  one  given  to  each 
branchial  leaf.  From  the  capillary  branches 
of  these  arteries  the  aerated  blood  is  received 
by  the  branchial  veins,  which,  as  in  fishes, 
concur  to  form  an  aorta  without  an  intervening 
ventricle.  From  the  last,  or  posterior  branchial 
artery,  on  each  side  is  given  off  a  branch 
which  goes  to  the  rudimentary  pulmonic  sac, 
and  which  ultimately  forms  the  trunk  of  the 
pulmonary  artery.  But  the  most  interesting 
and  important  change  is  that  by  which  the 
continuous  branches  of  what  were  originally 
the  branchial  arteries  combine  to  form  the  two 
trunks  of  the  aorta.  This  is  effected  by  means 
of  small  communicating  branches  between  the 
branchial  arteries  and  the  branchial  veins, 
which,  as  the  branchiae  become  absorbed,  and 
their  minute  branches  are  obliterated  and  lost, 
gradually  enlarge  until  they  become  continuous 
trunks;  and  the  artery,  which  was  originally 
branchial,  then"  becomes  the  single  root  of  the 
two  descending  aortae,  and  at  its  base  gives  off 
the  pulmonary  artery. 

The  two  veins  which  return  the  blood  from 
the  rudimentary  air-sacs  gradually  enlarge  as 
these  cavities  become  more  important,  and 
assume  the  character  of  lungs ;  and  at  length 
they  receive  the  name,  as  they  perform  the 
function,  of  pulmonary  veins.  These  by  de- 
grees become,  as  it  were,  distended  at  their 
point  of  union  with  the  heart,  and  ultimately 
form  the  second  auricle. 

This  general  description  will  be  better  un- 
derstood by  a  reference  to  the  subjoined 
figures  taken  from  the  tabular  views  of  M. 
St.  Ange,  of  which  an  English  edition  has 
been  published  by  Mr.  Jones.* 

The  following  detailed  description  of  those 
figures  is  necessary  to  the  correct  understanding 
of  this  intricate  but  interesting  arrangement. 
Fig.  18. 


The  first  period,  previous  to  any  change  having 
taken  place  in  the  branchiae,  is  given  in  fig.  18. 
Four  pairs  of  trunks  (1,  2,  3,  4)  go  off  from 
the  heart.  The  first  branch  on  each  side  (1) 
gives  off  a  small  anastomotic  branch  (5) ; 
after  which  it  becomes  divided  into  numerous 
branchial  filaments  (6);  these,  by  their  ulti- 
mate subdivision,  terminate  in  a  capillary  tissue 
or  network  (7),  from  which  arise  other  minute 
returning  vessels,  forming,  by  their  junction,  a 
single  large  vessel  (9),  which  brings  back 
blood  into  the  general  circulation  after  it  has 
been  aerated  in  its  course  through  the  branchiae. 
The  second  branch  (2)  also  gives  off  a  small 
one  (14)  previously  to  its  subdivision  in  the 
second  branchial  leaflet,  which  branch  enters 
the  returning  vessel ;  thus  producing  a  com- 
munication between  the  two  vessels  2  and  9, 
as  in  the  former  case.  The  returning  vessel 
then  terminates  in  the  arch  of  the  aorta,  in 
which  the  two  vessels  13  and  15  also  terminate. 
The  third  principal  vessel  (3)  is  similarly 
distributed  on  the  third  branchial  leaflet,  and 
the  corresponding  returning  vessel  (16)  termi- 
nates in  the  aorta,  as  in  the  other  case.  The 
arch  of  the  aorta,  thus  formed,  gives  off  a 
branch  (21),  which,  after  receiving  the  fourth 
branch  from  the  heart  (4),  goes  into  the  lungs 
(19). 

The  second  period,  shewn  in  Jig.  19,  occurs 
Fig.  19. 


*  Tabular  view  of  the  circulation  in  vertebrated 
animals. 
VOL.  I. 


w 

when  the  branchiae  begin  to  contract.  The 
anastomotic  branch  (5),  shewn  in  the  former 
figure,  is  not  much  enlarged,  and  assumes  the 
character  of  a  continuous  trunk  with  1 .  The 
branches  (11  and  12)  have  increased  in  size,  but 
the  original  continuation  of  1  going  to  the  bran- 
chiae, has  decreased  in  the  same  proportion.  The 
anastomotic  branch  (14)  has  acquired  the  size 
of  the  arch  of  the  aorta,  whilst  the  continuation 
of  2  is  diminished,  and  the  branchial  leaflet 
is  contracted  in  a  corresponding  degree.  The 
branch  3  has  become  exceedingly  small;  and  4, 
which  was  before  the  smallest,  is  now  the  largest 
of  all.  By  these  changes  in  the  relative  di- 
mensions of  the  different  vessels,  especially 
in  the  enlargement  of  the  anastomotic  branches, 
the  whole  system  of  the  circulation  is  gradu- 
ally being  altered,  until,  in  the  third  period, 
(fig.  20,)  it  has  assumed  the  character  of  that 
in  the  reptile,  by  the  total  obliteration  of  the 
branchiae  and  their  vessels,  and  the  enlarge- 
ment of  those  branches,  which,  at  first  only 
anastomotic,  have  now  become  principal. 
In  the  adult  condition  of  the  animal,  there- 

H 


AMPHIBIA. 


Fig.  20. 


fore,  the  heart  consists  of  a  single  ventricle, 
and  of  two  auricles.  The  existence  of  a  se- 
cond auricle  was  first  demonstrated  in  the 
higher  forms,  the  frogs  and  toads,  by  Dr.  Davy,* 
and,  although  in  the  latest  works  of  Cuvier 
and  Meckel  the  auricle  in  these  forms  is  de- 
scribed as  single,  yet  the  more  complicated 
structure  has  since  been  amply  confirmed  by 
many  other  anatomists.  Weberf  especially 
has  described  the  biauricular  structure  in  a 
large  American  frog ;  but  he  failed  to  demon- 
strate it  in  the  perennibranchiate  amphibia. 
From  a  very  interesting  paper  by  Mr.  Owen, 
in  the  first  volume  of  the  Zoological  Society's 
Transactions,}  it  appears  that  the  biauricular 
structure  of  the  heart  was  ascribed  by  Hunter 
to  all  the  amphibia  except  the  perennibranchiate 
forms;  in  which,  however,  the  existence  of 
the  left  auricle  has  been  satisfactorily  deter- 
mined by  Mr.  Owen,  who  has  also  given  some 
very  interesting  illustrations  of  the  mode  in 
which  the  coexistence  of  branchiae  and  rudi- 
mentary lungs  is  associated  with  certain  pecu- 
liarities of  the  circulation.  The  circulation  in 
the  adult  amphibia,  then,  assumes  exactly  the 
character  which  we  find  in  the  reptilia,  but 
in  the  most  simple  form. 

The  little  pulmonic  auricle  receives  the 
blood  perfectly  aerated  from  the  lungs  by 
means  of  the  pulmonary  veins.  The  systemic 
auricle  at  the  same  time  receives  the  impure 
blood  from  the  system  by  the  venae  cavae.  The 
blood  from  the  two  auricles  is  sent  together 
into  the  single  ventricle  where  it  becomes 
mixed,  and  this  mingled  arterial  and  venous 
blood,  thus  but  half  purified,  is  propelled  by 
the  same  impulse,  partly  into  the  pulmonary 
arteries  to  be  more  perfectly  purified,  and  the 
remainder  through  the  aorta  and  the  whole 
circulating  system  to  the  different  organs  of  the 
body.  The  aeration  of  the  blood,  therefore, 
is  but  imperfect;  a  condition  which  is  met 
with  equally  in  the  whole  of  the  reptilia. 

VI.  Respiration. -~- The  preceding  observa- 
tions on  the  circulation  have  in  some  measure 
necessarily  anticipated  the  account  which  we 
have  to  offer  of  the  correlative  function  of  re- 
spiration, and  the  character  of  those  changes 

*  Zool.  Journal,  vol.  ii. 

t  Beitrage  von  dem  Herzen  der  Batrachier,  8vo. 
1832. 

t   Part  iii.  p.  213. 


to  which  its  organs  are  subjected  in  the  transit 
of  the  amphibia  from  the  pisciform  to  the 
reptile  state.  Breathing  water,  in  the  first 
instance,  exclusively,  these  animals  are  fur- 
nished in  the  tadpole  condition  with  branchiae 
or  gills,  of  a  leaf-like  form,  considerably  sub- 
divided, though  far  less  so  than  in  the  fishes. 
These  branchiae  are,  in  the  first  instance,  in  all 
cases  external ;  but  in  the  higher  forms  of  the 
class  they  remain  so  situated  only  for  a  brief 
space,  becoming,  as  in  the  frogs  and  toads, 
internal  at  a  very  early  period  of  their  ex- 
istence. They  are  supported  by  cartilaginous 
or  osseous  arches,  connected  with  the  os  hy- 
oides,  and  the  changes  which  they  undergo  are 
accompanied  by  alterations  in  the  form  of  that 
bone,  to  which  allusion  has  already  been  made, 
and  an  account  of  which  will  now  be  given. 

At  that  period  of  the  tadpole's  existence, 
at  which  its  branchiae  are  in  full  action,  and 
the  lungs  still  restricted  to  the  state  of  a  black- 
ish, rudimentary  tissue,  we  find  the  tympanic 
bones,  (jigs.  21,  22,  e,)  developed  to  a  great 

Fig.  21.  Fig.  22. 


extent,  and  forming  the  basis  to  which  the 
branchial  apparatus  is  suspended,  by  means  of 
a  rather  thick  angular  portion,  f/gs.21,  22,  a.) 
This  has  been  shewn  by  Cuvier  to  represent 
what  in  the  fishes  is  composed  of  three  bones, 
and  is  the  medium  by  which  in  them  the 
whole  branchial  apparatus  is  suspended  to  the 
temporal,  and  which  bears  also  the  branchi- 
ostegous  rays.  Between  these  two  lateral 
branches  is  a  single  piece,  (Jigs.  21,  22,  &,) 
which,  according  to  the  same  authority,  cor- 
responds to  the  chain  of  bones  placed  in  most 
fishes  between  the  two  first  branchial  arches. 
To  the  posterior  point  of  this  bone  are  attached 
two  rhomboidal  portions,  (c,  c,)  to  the  external 
margins  of  which  are  suspended  the  arches  on 
which  the  branchiae  are  supported,  and  which 
represent  the  chain  of  bones  in  fishes,  bearing 
the  two  last  branchial  arches. 

As  the  age  of  the  tadpole  increases,  and  its 
metamorphosis  is  proceeding  unseen,  (Jigs. 
23,  24,)  we  find  the  branches  which  support 


Fig.  24. 


the  branchial  apparatus  («)  gradually  lengthen- 
ing, and  becoming  more  and  more  slender, 
and  at  length  exhibiting  the  two  long  cartila- 
ginous pieces,  by  which  the  os  hyoides  is 


AMPHIBIA. 


99 


attached  to  the  cranium  ;  (fg.  25,  «,)  the  single 
piece  (/>,)  and  the  two  rhomboidal  pieces  (r,  c ,) 
in  the  meantime  become  united  and  extended, 
(jigs.  25,  26,)  and  gradually  lose  by  absorption 

Fig.  25.  Fig.  26. 

d 


the  branchial  arches,  and  ultimately  form  a 
broad  disc,  the  body  of  the  os  hyoides,  the 
anterior  margin  of  which  on  each  side  is  di- 
lated into  a  scutiform  process,  and  the  posterior 
margin  bears  two  bony  appendages,  which  are, 
in  fact,  the  posterior  cornua  of  that  bone. 

Such  are  the  changes  which  this  bone  un- 
dergoes during  the  gradual  passage  of  the 
amphibious  animal  from  the  tadpole  state,  in 
which  it  represents  the  class  of  fishes,  to  its 
perfect  or  reptile  condition;  and  it  affords  a 
most  interesting  instance  of  the  manner  in 
which  the  true  nature  of  an  organ,  existing 
under  ambiguous  circumstances  in  one  class  of 
animals,  is  often  clearly  illustrated  by  its  cha- 
racters, or,  as  in  the  present  instance,  by  its 
transformations,  in  another. 

The  minute  filiform  branchiae,  which  are 
appended  to  the  tadpole  of  the  frog  im- 
mediately behind  the  head,  have  essentially 
the  same  structure  as  is  observed  in  the  gills 
of  the  perennibranchiate  family,  as  the  siren 
and  the  proteus,  though  in  a  different  form. 
In  the  proteus  each  branchia  consists  of  three 
principal  divisions  or  branches,  from  each  of 
which  proceed  seven  or  eight  leaves,  again  sub- 
divided into  numerous  regular  leaflets  form- 
ing the  ultimate  divisions  of  the  branchiae,  on 
which  the  extreme  capillary  branches  of  the 
vessels  ramify,  and  in  which  the  blood  under- 
goes its  necessary  change.  A  minute  rami- 
fication of  the  branchial  artery,  conveying  the 
impure  blood  from  the  heart,  enters  each  leaf- 
let at  its  base,  (jig.  27,  a.)  and  passes,  along 

Fig.  27. 

fr- 


its shorter  or  inner  margin,  giving  off  capillary 
branches  in  its  course,  which,  after  meandering 
over  the  surface  of  the  leaflet,  and  commu- 
nicating with  each  other  in  various  directions, 
pass  over  to  the  opposite  margin  of  the  leaflet, 
and  reunite  in  a  corresponding  ramification  of 
the  branchial  vein  (6),  which  passes  out  at 
the  base  to  combine  with  the  corresponding 
branches  from  the  other  leaflets,  and  convey 
the  aerated  blood  back  to  the  heart.  This  is 
the  general  structure,  modified  however  in  the 
different  genera,  by  which  this  important  func- 
tion is  effected  in  all  the  amphibia,  as  long  as 
they  are  confined  to  their  aquatic  life ;  and 
whilst  the  higher  groups  lose  these  organs  as 
they  advance,  and  acquire  the  necessary  organs 
for  atmospheric  respiration,  those  of  the  lower 
forms  retain  them  throughout  life,  coexistent 
with  rudimentary  lungs ;  and  thus  probably 
exhibit  the  remarkable  phenomenon  of  a  two- 
fold mode  of  respiration  at  one  and  the  same 
time  in  the  same  individual. 

Such,  then,  is  the  general  structure  of  the 
organs  of  aquatic  respiration,  whether  in  the 
early  and  transitory  form  in  which  it  is  seen  in 
the  frog  and  the  salamander,  or  in  the  perma- 
nent character  which  belongs  to  it  in  the  peren- 
nibranchiate group  of  the  siren,  the  axolotl,  the 
menobranchus,  and  the  proteus.  But  as  the 
former  of  these  groups  acquires  gradually  a  per- 
fect and  unmixed  atmospheric  respiration,  and 
as  the  pulmonary  cavity  serving  this  office  is 
only  slowly  developed,  so  we  find  in  the  pe- 
rennibranchiate forms  that  the  lungs  also  exist, 
though  in  little  more  than  a  rudimentary  state. 
The  early  condition  of  the  lungs  in  the  cadu- 
cibranchiate  genera,  in  which  they  ultimately 
exhibit  a  somewhat  advanced  structure,  is  that 
of  a  mere  rudimentary  sac,  without  internal 
cells  or  any  appearance  of  even  the  commence- 
ment of  that  more  perfect  structure  which  they 
afterwards  acquire.  Gradually,  however,  the 
inner  surface  is  furnished  with  small  processes, 
forming  little  sacs  or  cells,  on  which  the  capil- 
lary branches  of  the  pulmonary  vessels  ramify, 
and  through  the  infinitely  attenuated  surfaces 
of  which  the  impure  blood  undergoes  its  essen- 
tial process  of  depuration. 

In  the  lower  forms  of  the  class,  as  in  it\e  pro- 
teus anguinus  for  instance,  the  air-bags,  for  they 
scarcely  deserve  the  name-of  lungs  in  this  state, 
never  arrive  at  this  advanced  stage  of  develop- 
ment, but  remain  permanently  in  the  condition 
of  simple  membranous  sacs.  Every  part  of 
the  apparatus  belonging  to  that  organ  is  equally 
rudimentary.  The  glottis  consists  of  nothing 
more  than  a  small  slit  in  the  lower  part  of  the 
fauces,  placed  between  the  branchial  apertures 
of  each  side.  The  margin  of  this  little  opening, 
which  has  no  cartilaginous  ring  to  support  it,  is 
furnished  with  a  small  soft  pair  of  muscles,  by 
which  it  is  opened.  The  tube  leading  from  this 
opening  speedily  bifurcates,  and  one  passes  to 
each  air-bag.  In  this  rudiment  of  a  trachea 
and  of  bronchi,  there  is  no  appearance  of  car- 
tilaginous rings ;  it  is  a  mere  membranous 
canal,  each  branch  of  which  opens  without  any 
other  apparatus  into  its  air-cell.  From  the 
perfect  condition  of  the  branchiae,  and  the  very 

H  2 


100 


AMPHIBIA. 


simple  structure  of  these  pulmonary  sacs,  it  will 
readily  be  seen  that  the  function  of  respiration 
could  be  only  very  ineffectively  aided  by  the 
latter  organs,  even  were  there  no  other  diffi- 
culty arising  from  the  imperfect  structure  of  the 
apparatus  which  in  the  air-breathing  amphibia 
serves  the  office  of  conveying  the  air  into  the 
lungs.  A  short  description  of  the  means  by 
which  the  act  of  inspiration  is  effected  in  the 
frog  will  enable  us  to  judge  how  far  it  may  be 
possible  that  the  rudimentary  lungs  in  the  pro- 
leus  and  siren  are  to  be  considered  as  performing 
any  such  function. 

In  the  adult  frog,  toad,  salamander,  and  all 
others  of  the  higher  orders  of  amphibia,  the 
reception  of  air  into  the  lungs  is  effected  not 
by  the  primary  expansion  of  the  pulmonic  cavity 
and  the  consequent  rush  of  air  into  it,  but  by 
the  act  of  forcing  air  into  the  lungs,  or  in  fact 
by  a  simple  act  of  swallowing.  This  is  effected 
in  the  following  manner.  The  os  hyoides  and 
tongue  are  brought  downwards  to  a  considerable 
extent,  and  the  cavity  of  the  mouth  being  thus 
much  enlarged,  the  air  enters  by  the  nostrils. 
The  pharynx  is  then  shut  at  the  posterior  part, 
so  as  to  prevent  the  passage  of  air  into  the  ceso- 
phagus,  and  the  cavity  being  suddenly  con- 
tracted by  means  of  the  muscles  acting  on  the 
os  hyoides,  the  air  is  necessarily  forced  through 
the  glottis  and  trachea  into  the  lungs,  as  the 
posterior  nares  are  closed  either  by  their  mar- 
gins acting  as  a  valve,  or  by  the  pressure  of  the 
tongue  against  them.  This  view  of  the  mode 
of  inspiration  explains  the  cause  of  the  well- 
known  fact,  that  if  the  mouth  of  frogs  be  held 
open  they  perish  from  actual  suffocation  ;  for 
the  motions  of  the  os  hyoides  being  thus  im- 
peded, and  an  external  passage  being  also 
afforded  for  the  air,  respiration  by  the  injection 
of  air  into  the  lungs  is  obviously  impossible. 
Any  other  mode  of  inspiration,  connected  with 
the  primary  expansion  of  the  thoraco-abdo- 
minal  cavity  is  obviously  impossible  in  the  frog 
and  its  congeners,  from  the  total  absence  of  ribs. 
It  may  not  be  out  of  place  to  explain  here  the 
mode  in  which  the  peculiar  noise  uttered  by  the 
male  frog,  called  croaking,  is  produced.*  Ac- 
cording to  the  observations  of  P.  Camper,  the 
inspired  air  is  forced  against  the  inferior  surface 
of  the  tongue,  the  protuberance  of  which  di- 
vides it  as  it  were  into  two  currents,  which  pass 
into  the  membranous  sacs  adhering  to  the 
lower  jaw  and  existing  exclusively  in  the  males. 
From  these  sacs  it  is  directed  over  the  tongue, 
and  by  its  vibration  the  peculiar  sound  in  ques- 
tion is  produced. 

It  is  an  interesting  question  whether  in  the 
perennibranchiate  amphibia,  the  organs  which 
have  just  been  described  as  rudimentary  lungs, 
do  ever  serve  the  purposes  of  respiration  in 
even  the  smallest  degree ;  and  it  is  one  of  no 
small  difficulty.  The  superficial  structure  of 
the  nares  in  the  siren  and  the  proteus,  in  which 
they  almost  exactly  resemble  those  of  fishes, 
and  which  would  preclude  the  mode  of  inspi- 
ration practised  by  the  frogs,  together  with  the 
slight  and  attenuated  character  of  the  mem- 

*  Comment.  Soc.  Reg.  Scient.  Getting,  v.  ix. 


branous  tube  and  sacs,  would  almost  lead  to 
the  conclusion,  assumed  by  Rusconi,that  in  the 
proteus  at  least  these  organs  do  not  exercise 
any  function  appertaining  to  respiration.  If 
these  animals  be  confined  for  a  considerable 
time  in  the  same  water,  the  branchiae  become 
purple  instead  of  having  the  florid  red  colour 
which  characterizes  them  in  a  healthy  state, 
and  they  die  asphyxiated.  On  the  other  hand, 
the  very  excitement  of  the  two  sacs,  accom- 
panied by  tubes  of  such  length,  and  opening  to 
the  pharynx  by  a  sort  of  simple  glottis,  go- 
verned by  a  distinct  muscular  apparatus,  would 
seem  to  warrant  the  opinion  that  a  nearer  affi- 
nity to  true  lungs  is  to  be  traced  in  these 
organs  than  in  the  air-bag  of  fishes,  though 
recent  observations  have  shewn  the  latter  organ 
to  be  analogous  to  the  lowest  rudimentary  state 
of  lungs  in  the  higher  animals.  The  chain  of 
affinities,  therefore,  is  here  perfect,  as  far  as  re- 
gards the  pulmonary  cavities. 

VII.  The  nervous  system. — The  centre  of 
the  nervous  system  offers  a  not  less  striking  in- 
stance of  the  progressive  development  of  the  am- 
phibia in  their  passage  from  the  pisciform  to  the 
reptile  state  than  those  which  we  have  already 
shewn  in  the  organs  of  the  other  functions  of  the 
body.  The  condition  of  the  brain  in  the  early 
state  of  the  frog  tadpole,  the  genus  in  which  the 
changes  are  most  strongly  marked,  is  almost  ex- 
actly that  which  it  possesses  in  the  fishes.  The 
linear  arrangement  of  the  different  lobes,  the 
bread  and  lobed  form  of  the  medulla  oblongata, 
the  small  cerebellum,  the  large  size  of  the  op- 
tic thalami,  with  the  distinct  ventricles  which 
they  contain,  and  the  very  diminutive  extent  of 
the  hemispheres,  all  evince  a  low  degree  of 
development,  and  one  not  yet  emerged  from 
that  which  we  find  in  the  brain  of  fishes.  The 
same  imperfect  character  is  also  observed  in  the 
spinal  marrow,  which  even  in  the  frog  is  con- 
tinued into  numerous  coccygeal  vertebrae,  and 
as  the  extremities  are  not  yet  in  existence,  is 
devoid  of  those  enlargements  which  afterwards 
take  place  where  the  nerves  of  the  anterior  and 
posterior  members  are  given  off.  The  brain 
becomes  developed,  however,  in  a  very  short 
period  ;  the  changes  which  take  place  being 
very  rapid,  though  at  last  not  very  considerable; 
the  hemispheres  become  enlarged,  expanding 
laterally  and  in  some  measure  upwards,  con- 
stituting the  first  step  towards  that  superiority 
in  position,  as  well  as  in  size,  over  the  other 
lobes,  which  is  so  conspicuous  a  character  of 
these  important  portions  of  the  brain  in  the 
higher  animals.  Fig.  28.  represents  the  brain 


1,  pneumogastric  nerve; 
2,  ninth  pair;  3,  sixth 
pair  ;  4,  acoustic  ;  5,  fa- 
cial ;  6,  the  eye  ;  7,  optic 
nerve  and  its  tubercle  ;  8 
and  9,  base  of  the  hemi- 
spheres ;  10,  anterior  por- 
tion of  ditto  ;  11,  pedicle 
of  olfactory  lobe. 

in  the  common  frog  after  Serres.     As  the  limbs 
begin  to  make  their  appearance,  the  enlarge- 


AMPHIBIA. 


101 


ments  of  the  spinal  cord  are  observed  to  take 
place,  and  the  contraction  of  the  coccygeal  ver- 
tebra; into  a  single  linear  bone,  is  accompanied 
by  a  corresponding  diminution  in  the  length  of 
that  part  of  the  spinal  marrow,  which  at  length 
only  extends,  in  the  form  of  a  small  filament, 
into  the  anterior  third  of  that  bone. 

The  inferior  condition  of  the  brain  which  has 
been  described  as  existing  in  the  tadpole  of  the 
higher  species,  is  permanent  in  the  proteus  and 
other  perennibranchiate  genera ;  so  that  the 
brain  of  the  animal  just  named  bears  a  very 
obvious  resemblance  to  that  of  the  larva  of  the 
aquatic  salamander  or  triton. 

VIII.  The  organ  of  vision. — The  eye  differs 
considerably  in  its  form  and  magnitude  in  dif- 
ferent genera  of  the  amphibia,  and  without  any 
very  apparent  relation  to  either  their  habits  or 
their  circumstances.  In  the  frogs  and  some 
others  they  are  remarkably  large  and  prominent ; 
in  the  salamanders  they  are  comparatively  small, 
though  from  their  at  least  equally  aquatic 
habits,  this  difference  might  perhaps  have 
scarcely  been  anticipated,  and  in  the  coecilia,  as 
the  name  imports,  the  eyes  are  scarcely  if  at  all 
visible.  In  the  latter  animal  the  same  object 
has  doubtless  been  intended  by  this  absence  of 
vision,  as  in  the  mole  and  many  other  ani- 
mals, whose  common  subterranean  mode  of 
life  would  render  the  possession  of  acute 
sight  not  only  generally  useless,  but  an  extreme 
inconvenience  on  their  occasional  appearance 
above  the  surface. 

In  some  points  of  their  structure  the  eyes  of 
the  amphibia  are  not  remotely  related  to  those 
of  the  fishes  ;  as,  for  instance,  in  the  flattened 
anterior  surface  of  most  of  them,  arising  from 
the  small  supply  of  the  aqueous  humour,  and 
in  the  depth  of  the  crystalline.  In  some  of 
the  lower  forms,  there  can  scarcely  be  said  to 
be  a  true  orbit,  the  eyes  being  fixed  as  it  were 
in  the  integuments,  and  surrounded  by  a  mass 
of  minute  veins,  intermixed  with  extremely 
small  branches  of  nerves.  Rusconi  states  that  in 
the  proteus  he  was  not  able  to  discover  muscles, 
nor  even  the  optic  nerve  ;  though  on  carefully 
and  gently  raising  the  hemispheres  of  the  brain 
a  minute  nervous  filament  was  seen  going  to- 
wards the  foramen  which  serves  for  the  passage 
of  the  ophthalmic  artery ;  but  whether  this 
was  the  optic  nerve  or  not,  appears  a  matter  of 
entire  doubt.  In  fact,  the  structure  of  the  eye 
in  this  animal,  on  the  whole,  is  very  imperfect. 

In  the  frog,  on  the  contrary,  the  eye  is  fully 
developed,  and  all  the  essential  parts  of  its 
structure  sufficiently  conspicuous.  The  globe 
of  the  eye  is  large  and  projecting ;  the  scle- 
rotic is  considerably  solid  and  tough,  and  semi- 
transparent  ;  the  cornea  is  large,  and  though 
somewhat  flattened,  is  much  less  so  than  in 
fishes,  or  in  the  lower  forms  of  the  elass.  The 
inner  surface  of  the  choroid  is  extremely  black, 
and  the  external  of  a  silvery  whiteness.  The 
ciliary  processes  have  not  with  certainty  been 
discovered  in  these  animals,  unless,  as  Altena 
suggests,  a  little  tubercular  mass,  occupying 
nearly  their  situation,  and  closely  connected 
with  the  edge  of  the  choroid  and  with  the  cap- 


sule of  the  crystalline,  may  be  a  modification 
of  this  structure.  The  iris  is  covered  on  its 
posterior  surface  with  pigmentum  nigrum  ;  the 
anterior  having  a  shining  metallic  lustre,  pre- 
cisely similar  to  that  which  we  see  in  fishes. 
The  contractility  of  the  pupil  asserted  by 
Carus  is  denied  by  Altena  and  others.  The 
retina  is  thick,  and  covers  the  whole  internal 
surface  to  the  capsule  of  the  crystalline.  The 
vitreous  humour  is,  in  proportion,  abundant, 
and  the  lens  is  large  and  of  a  spheroidal  shape, 
consisting  of  numerous  concentric  laminae,  en- 
closing a  nucleus  of  extreme  density,  exhibiting 
a  close  relation  to  the  state  of  this  part  in 
fishes.  There  are  in  the  frog  three  nalpebrae ; 
or  perhaps,  with  greater  strictness  ot  analogy, 
it  might  be  said  that  there  are  two  palpebrae, 
and  a  sort  of  expansion  of  the  inferior,  serving 
as  a  membrana  nictitans.  The  superior  pal- 
pebra  is  small,  and  is  not  possessed  of  any 
degree  of  mobility;  the  inferior  is  broad,  ex- 
panded, and  semitransparent.  It  has  an  in- 
ternal membranous  expansion,  which  has  just 
been  alluded  to,  and  which  is  capable  of  cover- 
ing the  whole  eyeball. 

IX.  The  organ  of  hearing. — The  function 
of  hearing  exists  in  very  different  degrees  in 
the  different  groups  of  amphibia.  The  aquatic 
habits  to  which  the  lower  forms  are  confined 
by  their  branchial  respiration,  would  render  an 
acute  perception  of  sonorous  impulses  as  unne- 
cessary as  it  would  be  incompatible  with  the 
dense  medium  in  which  they  live ;  and  we  find 
in  this  sense,  as  in  every  other  function  of  the 
body,  the  most  perfect  concord  existing  be- 
tween the  habits  of  the  animal  and  its  structural 
arrangements.  The  pisciform  aquatic  genera 
of  this  class,  therefore,  are  found  to  possess  as 
near  an  affinity  to  the  fishes  in  the  structure  of 
the  organ  in  question  as  in  most  others ;  and  in 
this  they  are  also  imitated  by  the  tadpole  state 
of  the  higher  reptiliform  groups,  the  adult 
condition  of  which  exhibits  a  much  more  ad- 
vanced development  of  the  acoustic  organ.  In 
the  proteus  and  the  allied  genera,  there  is 
neither  a  tympanic  cavity,  nor  membrana  tym- 
pani ;  it  consists  of  a  large  cavity  hollowed  as 
it  were  out  of  the  temporal  bone,  at  the  bottom 
of  which  cavity  is  the  sacculus  with  its  creta- 
ceous body  ;  the  fenestra  oval  is  is  closed  by  a 
bony  lamina,  the  representative  of  the  stapes. 
Behind  the  sacculus  are  the  membranous  semi- 
circular canals.  The  whole  organ  is  covered 
externally  by  the  integuments,  without  any  pos- 
sible communication  with  the  atmosphere. 

In  the  frog,  on  the  other  hand,  the  whole 
structure  is  more  complicated.  The  sacculus, 
which  is  membranaceous,  is  filled  with  the 
cretaceous  matter,  which  is  here  semifluid, 
having  the  appearance  of  cream.  The  semi- 
circular canals  are  contained  within  the  sub- 
stance of  the  temporal  bone.  The  ossicula 
auditus  are  three,  united,  and  contained  within 
the  tympanum,  which  they  traverse,  and  are 
attached  to  the  membrana  tympani,  a  broad 
round  membrane,  perfectly  superficial,  and  very 
distinct  from  the  surrounding  integument.  The 
cavity  of  the  tympanum  is  not  capacious.  It 


102 


AMPHIBIA. 


communicates  with  the  external  air  by  means  of 
an  Eustachian  tube  passing  from  it  to  the 
fauces.  In  all  the  essential  parts  of  this  struc- 
ture, there  is  but  little  variation  from  that 
which  exists  in  the  true  reptilia. 

X.  The  organ  of  smell. — The  nares  in  the 
perennibranchiate  amphibia  are,  like  those  of 
fishes,  confined  to  little   more  than   a   slight 
cavity  on  the  anterior  part  of  the   head,  and 
having  no  continued  canal  by  which  they  can 
communicate  with  the  cavity  of  the  mouth.     In 
the  proteus  the  similarity  of  this  organ  to  that 
of  fishes  is  so  complete,  that    even    the    pli- 
cated radiations  of  the  lining  pituitary  mem- 
brane are  almost  exactly  imitated.      It  is  of 
considerable  size,  and  is  contained  in  a  length- 
ened canal  or  cavity,  the  parietes  of  which  are 
in  no  part  osseous.     The  nostrils  terminate  im- 
mediately under  the  upper  lip.     The  olfactory 
nerves  are  rather  large,  and  no  sooner  emerge 
from  the  cavity  of  the  cranium  than  they  divide 
into  numerous  branches  of   various    lengths, 
which   enter  every  part  of  the  soft  pituitary 
membrane. 

In  the  more  highly  developed  genera  the 
organ  of  smell  has  the  more  advanced  structure 
which  is  observed  in  the  reptilia.  The  nostrils 
are  partly  cartilaginous,  partly  osseous,  and 
extend  into  the  cavity  of  the  mouth,  though  the 
posterior  openings  are  placed  much  more  for- 
ward than  in  the  higher  classes  of  vertebrata. 
The  olfactory  nerves  enter  the  nostrils  through 
two  openings  in  the  ethmoid  bone.  The  ab- 
sence of  the  convoluted  and  extensive  surfaces 
of  the  turbinated  bones,  the  entire  simplicity  of 
the  canal  of  the  nostrils,  and  the  small  extent  of 
its  surface,  must  restrict  these  animals  to  a  very 
circumscribed  enjoyment  of  this  function;  and 
it  is  probable  that  the  sensibility  to  odours  is 
much  more  acute  in  the  aquatic  forms,  in  which 
the  organs  of  sight  and  of  hearing  are  so  im- 
perfectly developed,  than  in  the  frogs,  in  which 
the  organs  of  these  senses  are  much  more 
elaborately  formed. 

XI.  Of  the  organ  of  taste. — The  sense  of 
taste,  in  all  the  amphibia,  as  well  as  in  fishes, 
is  probably  very  obtuse.     The  tongue  in  the 
urodela  is  small,  and  attached  closely  at  every 
part.     In   the   anoura,   on  the  contrary,  it  is 
developed    to  an  extraordinary  degree;    it   is 
very  long,  bifid,  and  the  anterior  half  is  not 
only  free,  but,  in  its  quiescent  state,  doubled 
back  upon  the  posterior  fixed  part,  and  capa- 
ble of  being  thrown   forwards  and  again   re- 
tracted with  the  rapidity  of  lightning,  serving 
as    a    most   efficient    means   of  arresting  the 
quickest  movements  of  insects,  which  it  con- 
veys into  the  back  part  of  the  mouth  to  be 
swallowed. 

The  application  of  the  tongue  as  an  assistant 
in  respiration,  by  closing  the  posterior  nares,  in 
all  higher  groups  of  the  class,  has  been  before 
alluded  to. 

XII.  The  dermal  or  tcgumentari/  system. — 
The   absence   of  all   hard   scaly    adventitious 
covering  to  the  skin  of  the  amphibia  is  one  of 
the  most  common,  or  perhaps  it  may  be  said, 
the  only  universal  peculiarity  by  which  they 


are,  as  a  class,  distinguished  from  all  reptilia. 
The  amphibious  nature  of  their  progressive 
development,  or  the  existence  at  the  earliest 
period  of  even  rudimentary  branchiae,  can 
scarcely  be  said  to  be  without  exceptions,  as 
several  genera  have  already  been  mentioned  as 
not  having  yet  been  observed  in  this  condition. 
But  the  naked  skin  is  a  character  belonging 
equally  to  all,  from  the  serpentiform  coecilia  to 
the  typically  amphibious  frog,  and  the  pisciform 
axoloth  and  proteus. 

The  skin  of  the  aquatic  genera  is  soft,  smooth, 
and  furnished  with  a  secreting  surface,  by 
means  of  which  it  is  kept  constantly  moist, 
and  in  a  state  suitable  for  that  cutaneous  respira- 
tion which  strikingly  characterises  these  ani- 
mals. Many  of  those  which  are  generally 
inhabitants  of  the  land,  as  the  terrestrial  sala- 
manders, the  toads,  and  others,  are  provided 
with  numerous  cutaneous  glands,  which  secrete 
a  tenacious  milky  fluid,  which  is  somewhat 
acrid,  and  may  perhaps  be  deleterious  if  swal- 
lowed in  any  quantity  ;  though  the  old  opinion 
of  the  poisonous  nature  of  these  animals  is 
altogether  without  foundation.  The  fluid  which 
is  poured  out  from  these  cutaneous  follicles  in 
the  common  salamander  is  copious,  of  a  milky 
colour,  and  consists  of  mucus,  with  the  addi- 
tion of  some  acrid  matter,  the  nature  of 
which  is  not  yet  known.  From  the  quan- 
tity which  is  suddenly  secreted  when  the  ani- 
mal is  injured  or  any  part  of  the  surface 
irritated,  it  is  not  improbable  that  even  the 
effect  of  fire  may  for  a  few  moments  be  arrested 
by  it ;  and  thus  may  have  originated  the  fable 
of  the  salamander  having  the  power  of  remaining 
unconsumed  and  unhurt  when  thrown  upon 
burning  coals.  The  acrid  nature  of  the  cuta- 
neous secretion  of  the  toad  was  confirmed  by 
the  observations  of  Dr.  Davy  a  few  years  since. 

The  cuticle  of  these  animals  is  frequently 
shed ;  that  of  the  aquatic  species  comes  off  in 
shreds,  and  is  washed  away  from  the  skin.  In 
the  toads  a  very  curious  process  takes  place  for 
its  removal.  When  the  cuticle  has  become  dry 
and  unyielding,  and  a  new  and  softer  surface 
is  required,  the  deciduous  layer  splits  down 
the  median  line  of  the  back  and  of  the  abdo- 
men at  the  same  time.  The  whole  cuticle  is 
thus  divided  into  two  parts.  By  numerous  con- 
vulsive twitchings  and  contortions  of  the  body 
and  legs,  this  separation  becomes  more  and 
more  considerable,  and  the  cuticle  is  gradually 
brought  off  the  back  and  belly  in  folds  towards 
the  sides.  It  is  then  loosened  from  the  hinder 
legs  by  similar  movements  of  those  limbs,  and 
finally  removed  from  them  by  the  animal  bring- 
ing first  one  and  then  the  other  forwards  under 
the  arm,  and  by  then  withdrawing  the  hinder 
leg  its  cuticle  is  left  under  the  fore  leg.  The 
two  portions  are  now  pushed  forwards  to  the 
mouth,  by  the  help  of  which  the  anterior  ex- 
tremities are  also  divested  of  it.  The  whole 
mass  is  now  pushed  by  the  hands  into  the 
mouth,  and  swallowed*  at  a  single  gulp. 
The  new  cuticle  is  bright,  soft,  and  covered 
with  a  colourless  mucus;  the  old  skin  was 
harsh,  dry,  dirty,  and  opaque.  This  curious 


AMPHIBIA. 


103 


process  I  have  repeatedly  watched.  I  have 
observed  shreds  of  cuticle  hanging  about  the 
terrestrial  salamander,  which  would  lead  to  the 
opinion  that  this  animal  does  not  disengage 
itself  from  its  deciduous  skin  m  the  same 
manner  as  the  toad;  but  as  the  .individuals 
under  notice  were  not  in  health,  the  observa- 
tion is  inconclusive. 

But  the  most  interesting  circumstance  con- 
nected with  the  functions  of  the  integuments  of 
these  animals,  or  indeed  with  any  part  of  their 
economy,  is  their  cutaneous  respiration,  or  the 
power  which  the  dermal  surface  possesses  of 
effecting  those  changes  in  the  blood,  which  are 
essential  to  life,  and  which  are  usually  per- 
formed by  particular  organs  set  apart  for  that 
express  object,  and  modified  according  to  the 
aquatic  or  atmospheric  medium  in  which  the 
depurating  agent  is  applied  to  them. 

Although  the  experiments  of  Spallanzani  had 
long  ago  demonstrated  that  carbonic  acid  was 
produced  by  the  contact  of  the  atmosphere 
with  the  skin  of  frogs,  the  subject  had  never 
been  examined  with  the  care  and  attention 
which  its  importance  demands,  until  the  in- 
vestigations of  Dr.  Edwards  of  Paris,  given  in 
his  work  "  On  the  Influence  of  Physical  Agents 
on  Life,"  set  the  question  at  rest,  and  esta- 
blished the  proposition  by  a  series  of  interesting 
experiments,  so  admirably  arranged,  so  satis- 
factorily conducted,  and  so  logically  reasoned 
upon,  as  to  leave  no  vacuity  in  the  regular 
line  of  induction,  nor  doubt  of  the  strict  correct- 
ness of  his  conclusions. 

The  existence  of  a  cutaneous  respiration  in 
frogs  was  proved  by  the  simple  experiment  of 
tying  a  piece  of  bladder  over  the  head  so  tightly 
as  to  produce  complete  strangulation,  and  then 
placing  them  under  water.  On  examining  the 
air  contained  in  the  vessel  after  an  hour  or  two, 
a  sensible  quantity  of  carbonic  acid  was  de- 
tected. 

On  placing  frogs  in  vessels  filled  respec- 
tively with  river  water  and  with  water  which 
had  been  deprived  of  its  air  by  boiling,  and 
inverted  over  the  apertures  perforated  in  the 
shelf  of  a  pneumatic  trough,  containing  ninety- 
eight  and  a  half  pints,  those  in  the  latter  lived 
on  the  average  little  more  than  half  as  long  as 
those  in  the  aerated  water.  On  trying  the 
effect  of  stagnant  water  renewed  at  intervals, 
they  were  found  to  live  two  months  and  a  half, 
and  then  died  from  accidental  neglect  of  renew- 
ing the  water.  Similar  results  followed  ex- 
periments made  under  running  water.  The 
effects  of  temperature  in  these  experiments 
were  very  striking,  and  prove  that  the  duration 
of  life  under  water  is  in  an  inverse  proportion 
to  the  elevation  of  the  temperature  from  32°  to 
about  107,  at  which  point  the  animals  die 
almost  instantly.  But  these  effects  of  tempera- 
ture were  found  to  be  modified  by  an  increase 
of  respiration,  whether  by  their  rising  to  the 
surface  and  breathing  the  atmosphere,  or  by 
the  quantity  of  aerated  water  being  increased. 

Such  is  a  rapid  glance  at  some  of  the  results 
observed  by  this  distinguished  physiologist,  on 
the  cutaneous  respiration  of  aerated  water ; 


those  which  are  connected  with  atmospheric 
respiration  by  the  same  surface  are  no  less 
interesting.  In  order  to  render  the  experiments 
as  rigorously  satisfactory  as  possible,  pulmo- 
nary respiration  was  prevented  by  actual  stran- 
gulation, rather  than  by  keeping  the  mouth 
open,  a  method  which  appears  liable  to  some 
degree  of  uncertainty.  A  ligature  was  passed 
round  the  neck  of  six  frogs,  using  the  most 
rigid  compression,  so  as  completely  to  exclude 
any  possible  passage  of  air.  One  of  them 
lived  twenty  days  ;  those  placed  in  five  ounces 
and  a  half  of  water  had  died  in  from  one  to 
three  days.  As  the  severity  of  the  operation 
of  strangulation  might  probably  have  hastened 
death,  another  mode  was  tried,  namely,  the 
total  excision  of  the  lungs, — an  operation  which 
appeared  to  produce  but  little  suffering;  the 
animals  were  then  placed  on  moist  sand.  Of 
three  frogs  thus  treated,  two  died  on  the  thirty- 
third  day,  and  the  remaining  one  on  the 
fortieth. 

Other  experiments  were  instituted  to  resolve 
the  converse  of  the  former  proposition,  whether 
life  can  be  prolonged  by  pulmonary  respiration 
alone,  unaided  by  that  of  the  skin  ?  The  re- 
sult of  the  experiments  made  upon  tree  frogs 
and  upon  the  bufo  obxtetricans,  was  that  pul- 
monary respiration  is  not  sufficient  to  support 
life,  without  being  accompanied  by  the  influ- 
ence of  the  skin. 

The  results  of  these  experiments  are  not 
only  highly  interesting  as  regards  the  habits  of 
the  particular  tribe  of  animals  which  were  the 
subject  of  them,  but  still  more  so  with  refer- 
ence to  some  important  questions  in  general 
physiology ;  but  as  their  bearing  on  these 
points  can  only  be  shown  by  viewing  them  in 
relation  with  all  the  other  subjects  treated  of  in 
the  admirable  work  from  which  they  are  taken, 
it  would  be  out  of  place  to  consider  them  here. 
It  is  impossible,  however,  not  to  be  struck 
with  the  evidence  they  afford,  that  the  respi- 
ratory organ,  that  surface  through  the  medium 
of  which  the  blood  undergoes  its  necessary 
change  by  the  action  of  oxygen,  whether  pul- 
monary, branchial,  or  cutaneous,  and  whether 
the  medium  of  its  access  be  water  or  the  at- 
mosphere, is  in  all  cases  similar,  being  a 
modification  of  the  cutaneous  surface.  And 
as  we  see  in  the  instance  before  us,  the  same 
surface  capable  of  performing  either  atmos- 
pheric or  aquatic  respiration,  the  inference  is 
obvious,  that  pulmonary  and  branchial  organs 
may,  and  probably  do,  possess  an  identity  of 
structure.When  it  is  considered  too  that  moisture 
is  absolutely  essential  to  atmospheric  respira- 
tion, whether  pulmonary  or  cutaneous,  the 
identity  of  the  two  processes  becomes  still 
more  unequivocal. 

This  view  of  the  subject  receives  considerable 
confirmation  from  the  fact  that  branchiae,  are 
in  many  animals  capable  of  exercising  the 
office  of  atmospheric  respiration  through  the 
medium  of  a  very  small  quantity  of  water  ;  as 
the  land  crabs  of  torrid  regions  are  enabled  to 
traverse  immense  districts  under  a  burning 
sun,,  by  means  of  those  little  reservoirs  of 


104 


AMPHIBIA. 


r,  described  by  Dr.  Milne  Edwards, 
formed  by  duplicatui-es  of  the  lining  mem- 
brane of  the  branchial  cavity.  The  eel  too,  as 
i>  well  known,  will  live  for  a  long  time  out  of 
water,  from  its  branchial  cavity  being  capable  of 
retaining  a  sufficient  quantity  of  water  to  bathe 
the  branch  iiv  for  a  considerable  time,  thus 
preserving  those  organs  in  a  respirable  state. 

XI II.  Of'  transpiration  ami  i>f  secretion. — 
The  particular  condition  of  the  skin  already 
d escribed,  naked  and  consisting  of  a  moist 
mucous  surface,  would  render  it  probable  that 
cutaneous  transpiration  should  be  exceedingly 
extensive  and  rapid  in  these  animals  :  this  is 
in  fact  the  case  to  such  an  extent,  that  when 
exposed  to  too  great  a  degree  of  heat,  the  eva- 
poration of  transpired  fluid  is  sufficient  to  pro- 
duce a  very  rapid  decrease  in  the  weight  of  the 
animal  ;  which,  if  exposed  for  a  sufficiently 
long  period  to  its  influence,  becomes  almost 
dried  up  and  d 

One  object,  and  that  not  an  unimportant 
one,  of  the  sensible  transpiration  of  fluid  in 
these  animals,  the  frogs  especially,  is  un- 
doubtedly to  preserve  the  skin  in  a  condition 
fit  for  the"  performance  of  that  cutaneous  respi- 
ration which  has  been  described.  But  its  still 
more  obvious  purpose  is  to  aflbrd  a  quantity  of 
fluid  for  evaporation  from  the  surface,  in  order  to 
reduce  and  equalize  the  temperature  of  the  body 
when  exposed  to  a  degree  of  heat,  sufficient  to 
incommode  or  injure  it.  This  will  appear 
very  reasonable  when  we  reflect  that  these  ani- 
mals will  die  in  a  few  minutes,  if  placed  in 
water  of  107  decrees  of  Fahr.,  though  respiring 
freely  with  the  head  above  the  water,  whilst, 
on  the  contrary,  they  will  support  for  hours  the 
action  of  damp  air  of  the  same  temperature. 

The  water  which  is  thus  transpired  is  not 
the  result  of  the  absorption  of  fluids  taken  in 
by  the  mouth,  for  these  animals  do  not  appear 
to  drink.  It  is  received  by  absorption  on  the 
surface  of  the  skin,  to  which  part  it  is  after- 
wards restored  when  necessary.  But  in  order 
to  be  re  idy  whenever  circumstances  call  for  its 
use.  the  fluid  thus  absorbed  is  conveyed  into  a 
membranous  cavity,  formed  generally  of  two 
lobes,  opening  into  the  cloaca,  where  it  is  re- 
tained, to  be  again  absorbed,  and  again  con- 
,  d  to  the  surface  for  the  purposes  just  men- 
tioned. \Yhen  a  frog  is  suddenly  alarmed,  or 
seized,  it  ejects  from  its  cloaca  a  quantity  of 
pure,  limpid  water,  for  the  purpose  of  lighten- 
ing itself,  that  it  may  leap  with  greater  facility. 
This  fluid  is  expelled  from  the  sac  in  question, 
and  is  often  mistaken  for  urine,  and  the  sac  for 
a  urinary  bladder.  Hence,  if  a  frog  be  kept  in 
a  moist  situation,  without  having  access  to 
water  in  any  form  but  in  vapour,  the  skin  is 
always  kept  moist,  and  the  water-bag  a 
filled. 

Such  is  the  function  attributed  in  the  first 
place  by  Townson  to  the  sac  in  question,  and 
after  him  by  Dumeril,  Altena,  and  others  :  but 
Cuvier.  Dr.  Grant,  and  many  other  anato- 
mists consider  that  it  is  the  true  urinary  blad- 
der. That  Townson's  opinion  is  correct  ap- 
pears, says  Altena,  ••  from  the  circumstance  that 


the  ureters  do  not  terminate  in  the  bladder,  but 
in  the  rectum  itself."  Dr.  Grant  states,  that  on 
the  contrary,  "the  bladder  receives  the  ureters." 

The  kidneys  are  of  a  lengthened  form,  in  the 
aquatic  genera,  but  are  shorter  in  the  frogs  and 
other  anoura. 

XIV.  On  the  restoration  of  lost  parts. — 
The  fact  that  parts  lost  by  accident,  or  re- 
moved for  the  purpose  of  experiment,  become 
reproduced  in  many  of  the  lower  animals,  has 
been  known  for  aces.  The  actual  multipli- 
cation of  the  species  in  many,  perhaps  all  the 
polygustrie  animalcula,  by  spontaneous  sepa- 
ration,— that  of  the  hydra" by  artificial  division, 
— the  restoration  of  lost  anus  in  the  different 
species  of  asterias,  of  the  anterior  or  posterior 
extremity  of  the  body  in  the  earthworm,  of 
the  claws  of  the  lobster,  and  other  Crustacea, 
and  of  portions  of  the  head  in  the  pulmo- 
niferous  mollusca,  are,  all  of  them,  phenomena 
which  have  attracted  the  attention,  and  occu- 
pied the  experiments  of  physiologists,  at  va- 
rious periods.  The  experiments  of  Plateretti, 
Spallanzani,  Murray,  Bonnet,  and  others,  have 
shewn  that  it  is  not  in  the  invertebrate  forms 
alone  that  we  are  to  look  for  this  phenomenon, 
but  that  the  amphibia,  and  even  some  reptilia, 
will  reproduce  either  the  limbs  or  the  tail, 
when  removed.  This  restoration  of  the  tail 
in  the  saurian  reptiles  is  indeed  a  common 
occurrence,  and  it  often  happens  that  the  new 
tail  is  double  through  the  whole  of  the  restored 
length. 

Of  all  the  observers  of  this  curious  phe- 
nomenon in  the  amphibia,  Bonnet*  stands  pre- 
eminent for  the  laborious  and  patient  zeal  with 
which  all  his  experiments  were  conducted,  no 
less  than  tor  the  conscientious  strictness  with 
which  they  are  recorded.  In  many  experi- 
ments he  cut  off  the  anterior  or  posterior  limbs 
of  the  common  water  salamander  or  triton, 
which  he  found  to  be  invariably  restored,  and 
even  the  toes  were  reproduced,  and  acquired 
some  degree  of  motion.  The  tails  were  also 
amputated  at  various  distances  from  the  base, 
and  were  always  renewed.  The  same  limb 
was  in  some  cases  removed  and  restored  four 
times  consecutively.  In  all  cases  it  was  ob- 
served that  warmth  encouraged  and  that  cold 
retarded  the  regeneration  of  the  part.  The 
restored  portions  were  not  generally  well- 
formed,  but  in  some  instances  varied  by  t\ 
in  others  by  defect.  One  of  the  most  t 
ordinary  results  was  that  which  followed  the 
extirpation  of  an  eye  from  one  of  these  ani- 
mals. In  the  course  of  a  year  this  organ  was 
completely  restored,  and  its  organization  was 
found  to  be  perfect. 

Dumeril  records  a  remarkable  experiment 
of  this  nature,  in  his  latest  work  on  the  rep- 
tilia.  The  subject  was  the  triton  mmr- 
monttus.  Three-fourths  of  the  head  were  cut 
off,  and  the  animal  was  deposited  at  the  bot- 
tom of  a  large  vessel  having  half  an  inch  depth 
of  water,  which  was  constantly  renewed.  It 
continued  to  live,  and  to  move  slowly.  The 

*  (Euvres.  iu  4to.     Neufchatel,  1769. 


AMPHIBIA. 


105 


nostrils,  the  tongue,  the  eyes,  and  the  ears 
were  gone;  the  animal  could  therefore  enjoy 
no  relation  to  external  objects  but  by  the  sense 
of  touch.  It  nevertheless  evinced  conscious- 
ness, creeping  cautiously  and  slowly  about, 
occasionally  raising  the  neck  to  the  surface  as 
if  attempting  to  breathe.  The  process  of  cica- 
trization at  length  completely  closed  the  aper- 
tures of  respiration  and  of  deglutition.  It  lived 
three  months  after  the  operation,  and  then  died 
from  accidental  neglect.  After  all,  this  expe- 
riment proves  only  the  respiratory  function  of 
the  skin,  a  fact  already  sufficiently  established 
by  the  observations  of  Dr.  Edwards  before 
detailed,  and  its  cruelty  does  not  appear  to  be 
compensated  for  by  its  results. 

XV.  Of  reproduction.— The  impregnation 
of  the  ova  in  the  amphibia,  is  effected  without 
actual  coitus ;  that  is  to  say,  it  either  takes 
place  out  of  the  body,  as  in  the  anoura,  or  the 
impregnating  fluid  is  received  by  the  mere 
contact  of  the  external  opening  of  the  cloaca 
in  the  two  sexes,  as  in  the  tailed  forms.  The 
only  exception  to  this  statement  is  in  the  land 
salamander,  the  male  of  which  has  a  small 
intromittent  organ.  The  act  itself  of  impreg- 
nation therefore  differs  materially  in  these  two 
divisions  of  the  class.  The  generative  organs 
of  both  sexes  are  double,  and  are  placed  sym- 
metrically in  the  abdomen.  The  testes  in  the 
higher  forms  of  the  class,  the  frogs  and  toads, 
are  small  globular  oval  bodies,  having  exter- 
nally a  bright  white  appearance,  from  the 
tunica  albuginea,  and  internally  a  somewhat 
loose  texture,  and  a  yellowish  colour.  They 
are  placed  behind  the  liver,  attached  to  the 
vertebral  column  ;  the  vasa  deferentia  are 
numerous,  disposed  in  pairs;  they  form  a 
small  epididymis,  and  passing  on  the  outer 
side  of  the  kidneys  back  towards  the  cloaca, 
dilate  into  vesiculae  seminales,  just  before  they 
terminate  in  that  cavity.  These  organs,  as  in 
many  other  animals,  become  much  enlarged  at 
the  breeding  season. 

The  ovaria  are  situated  in  the  anterior  and 
upper  part  of  the  abdomen,  and  are  internally 
divided  into  numerous  sacs,  by  duplicatures 
of  the  peritoneum,  by  which  also  they  are 
bound  to  each  side  of  the  spine.  These  sacs 
are  torn  at  the  period  of  depositing  the  eggs, 
whether  by  the  pressure  of  the  arms  of  the 
male,  as  asserted  by  Prevost  and  Dumas,  or 
otherwise,  appears  uncertain.  The  oviducts  are 
small  at  their  commencement,  and  become 
large  towards  their  termination  in  a  sort  of 
dilated  sac,  which  Altena  terms  the  uterus; 
they  are  of  a  pulpy  substance,  having  an  in- 
ternal secreting  surface;  and  the  eggs  during 
their  passage  through  them  become  enveloped 
in  a  gelatinous  mass.  They  dilate  into  a  sort 
of  uterine  cavity  just  mentioned,  which  opens 
into  the  cloaca. 

The  mode  by  which  the  eggs  of  the  frog 
pass  from  the  ovaries  into  the  oviducts  appears 
yet  to  be  doubtful.  The  observations  of  Pre- 
vost and  Dumas  on  this  subject  are  generally 
received  as  correct,  but  their  statements  are 
denied  in  some  particulars  by  Altena,  and 


doubted  in  others.  They  state  that  the  ova, 
detaching  themselves  from  the  ovaries,  are 
seized  by  the  opening  of  the  tube,  but  they  do 
not  state  the  mode  by  which  this  act  is  effected. 
It  is  a  question  which  was  long  since  examined 
with  great  care  by  Swammerdam,  and  which 
brought  him  into  a  controversy ;  and  he  con- 
fesses at  last  his  ignorance  of  the  mode  in  which 
it  actually  takes  place. 

The  ovaries  enlarge  greatly  at  the  breeding 
season,  and  the  ova  at  the  time  of  their  depo- 
sition fill  the  body  almost  to  bursting.  At  the 
time  of  impregnation  the  male  placing  himself 
on  the  back  of  the  female,  embraces  the  body  with 
astonishing  force  with  the  anterior  legs,  which 
are  pressed  under  the  axillae,  and  the  tuber- 
cular thumbs,  which  are  at  this  period  con- 
siderably enlarged  to  enable  him  to  retain  his 
hold,  are  so  essential  to  this  object,  that  if 
they  be  cut  off,  he  can  no  longer  clasp  the 
female  with  the  requisite  force.  The  instinct 
which  instigates  the  male  frog  to  this  act  at  the 
season  of  breeding  is  astonishingly  powerful, 
and  sometimes  no  less  remarkably  blind. 
Thus,  it  is  recorded  by  Walter,  and  has  been 
often  observed  by  others  since  his  time,  though 
the  object  of  this  curious  fact  has  been  un- 
accountably overlooked,  that  frogs  are  occa- 
sionally found  in  the  spring  adhering  with 
great  force  to  different  parts  of  the  skin  of 
pike  ;  and  a  near  relative  of  the  writer  of  this 
article  has  seen  an  instance  of  the  same  kind, 
where  several  frogs  were  so  closely  fixed  to  a 
large  pike  as  to  require  some  force  to  remove 
them.  This  instinct  of  adhesion  is,  in  fact, 
sometimes  fatal  to  its  legitimate  object.  I  have 
before  now  taken  from  the  water  a  large  con- 
glomeration of  male  frogs,  amounting  to  per- 
haps twelve  or  more,  with  one  solitary  female 
in  the  middle  of  the  mass,  dead  and  putrid, 
and  even  some  of  the  males,  towards  the  in- 
terior, pressed  into  an  almost  lifeless  and  shape- 
less lump. 

While  the  male  is  thus  closely  embracing 
the  female,  an  operation  which  sometimes  lasts 
for  more  than  a  month,  the  eggs,  to  the  num- 
ber of  several  hundreds,  are  gradually  ejected 
from  the  cloaca,  either  in  masses  as  in  the 
frog,  or  in  double  chaplets  as  in  the  toad,  and 
impregnated  by  the  sprinkling  of  the  semen, 
as  they  pass  out  under  the  male.  In  some 
species,  as  the  bufo  obstetricans,  the  female  is 
assisted  in  the  act  of  expulsion  by  the  hinder 
legs  of  the  male.  When  the  eggs  are  thus 
deposited  in  the  water,  the  jelly-like  substance 
in  which  each  is  enveloped  absorbs  a  large 
quantity  of  it,  and  the  whole  mass  speedily 
enlarges  to  many  times  the  size  of  the  animal 
from  which  it  was  expelled. 

The  male  of  the  bufo  obstetricans  just  men- 
tioned, when,  by  his  assistance,  the  eggs  are 
excluded,  attaches  them  to  his  thighs  by  glu- 
tinous threads,  and  carries  them  about  with 
him  until  the  young  are  ready  to  leave  them, 
when  he  seeks  a  pool  of  water  in  which  he 
deposits  them,  and  the  young  shortly  afterwards 
come  forth. 

The  impregnation    of    the    tailed    aquatic 


106 


AMPHIBIA. 


genera,  as  the  tritons,  is  effected  by  a  totally 
different  mode.  During  the  spring,  the  males 
acquire  a  considerable  dorsal  membrane,  which 
runs  the  whole  length  of  the  back  and  tail, 
and  is  sometimes  curiously  indented  or  fringed 
at  its  edge.  This  membrane  is  gradually  lost 
after  the  breeding  season,  and  its  use  appears 
to  be  to  assist  in  the  act  of  impregnation. 
The  male,  instead  of  adhering  to  the  female 
like  the  frog,  swims  by  her  side  pursuing  her 
in  all  her  rapid  and  changing  courses  through 
the  water,  till  at  length  both  remaining  for  a 
moment  quite  still,  he  suddenly  turns  up,  by 
the  assistance  doubtless  of  the  dorsal  mem- 
brane, and  places  for  an  instant  the  edges  of 
the  cloacal  aperture  in  contact  with  hers.  It 
is  at  this  instant  that  the  semen  is  ejected  and 
received.  The  eggs  are  afterwards  deposited 
slowly,  and  comparatively  few  in  number, 
upon  some  part  of  an  aquatic  plant,  on  which 
the  female  supports  herself  by  holding  by  her 
hinder  legs. 

When  the  embryo  has  gradually  acquired 
its  larva  development,  and  is  ready  for  its 
aquatic  life,  it  bursts  the  thin  membrane  which 
encloses  it,  and  emerges  in  the  fish-like  form 
which  has  been  so  often  alluded  to  in  this  paper. 

XVI.  Metamorphosis, — The  changes  which 
take  place  in  the  different  organs  during  the 
progress  of  this  extraordinary  phenomenon, 
have  been  already  detailed.  It  remains  to 
trace  the  general  form  of  the  animal  from  the 
egg  through  its  larva  condition  till  it  receives 
its  permanent  form,  and  to  point  out  some 
remarkable  peculiarities  observed  in  different 
genera. 

In  the  frog,  the  toad,  and  probably  all  the 
anoura,  the  respiratory  organs  undergo  a  double 
change,  the  branchiae  being  first  external  for  a 
very  brief  period,  and  afterwards  internal  during 
the  remainder  of  its  larva  existence.  In  all 
the  other  forms  in  which  branchiae  have  been 
detected,  they  remain  external  till  they  are  lost. 

The  tadpole,  whether  of  the  anoura  or  of 
the  urodela,  possesses,  at  first,  as  we  have  seen, 
the  same  means  of  progression  as  belong  to  the 
class  of  fishes.  That  of  the  triton  retains  its 
branchiae,  co-existent  with  four  perfect  legs, 
until  it  is  about  a  third  of  its  ultimate  length. 
In  the  frog  the  legs  which  first  make  their 
appearance  are  the  hinder  ones ;  and  from  the 
great  development  of  the  tail,  and  the  con- 
tinuous form  of  the  head  or  abdomen,  they  ap- 
pear as  if  they  came  through  immediately  be- 
hind the  head. 

As  the  terrestrial  salamander,  though  pre- 
ferring moist  places,  does  not  frequent  the 
water,  the  young  have  not  the  opportunity  of 
being  developed  in  that  medium ;  but  as  the 
essential  character  of  their  organisation  requires 
that  the  first  portion  of  their  existence  should 
be  passed  in  the  condition  of  a  tadpole  or  larva, 
we  find  that  the  whole  of  its  metamorphosis 
takes  place  whilst  in  the  oviduct,  where  it  is 
found  with  small  branchiae  on  each  side  of  the 
neck,  which  are  lost  as  the  animal  enters  upon 
its  terrestrial  existence.  Like  the  viper,  there- 
fore, this  animal  is  ovo-viviparous. 


The  arrest  of  the  metamorphosis  in  the  lower 
or  perennibranchiate  forms  is  confined  to  the 
organs  of  locomotion  in  part,  to  those  of  cir- 
culation, and  of  respiration.  The  organs  of 
reproduction  receive  their  full  development, 
though  even  in  these  there  is  a  considerable 
resemblance  to  those  of  the  fishes. 

One  of  the  most  remarkable  peculiarities  in 
the  whole  of  this  class,  with  regard  to  the  sub- 
ject now  under  consideration,  is  the  reproduc- 
tion and  metamorphosis  of  the  pipa  or  Surinam 
toad.  It  has  long  been  known  that  the  eggs 
are  developed  in  cells  on  the  buck  of  the 
mother;  but  the  facts  connected  with  this 
curious  circumstance  have  only  of  late  years 
been  ascertained.  It  is  now  established  that 
the  cells  on  the  skin  of  the  female  are  not 
persistent,  but  grow  as  the  eggs  enlarge,  and 
are  removed  after  the  young  leave  them.  The 
male  impregnates  the  eggs  as  the  toad,  but 
immediately  places  them  on  the  skin  of  the 
mother's  back;  here  they  are  attached  by  a 
tenacious  mucus,  and  the  skin  gradually  thickens 
in  the  interstices,  forming  at  length  a  cell  around 
each.  In  these  cells  the  young  ones  not  only 
leave  the  eggs,  but  actually  undergo  their 
metamorphosis ;  and  when  they  leave  the  back 
of  the  parent,  they  have  lost  all  the  characters  of 
the  tadpole,  and  have  become  perfect  animals. 

It  is  impossible  to  contemplate  the  structure 
and  habits  of  this  remarkable  class  of  animals 
without  being  struck  by  the  many  interesting 
points  which  they  offer  for  the  investigation  of 
the  physiologist.  Whether  we  consider  the 
evident  and  perfect  transition  which  many  of 
them  present,  from  the  form  and  structure  of 
an  inferior  to  that  of  a  superior  type  or  organiza- 
tion, the  facilities  which  they  afford  us  of 
tracing,  as  it  were  under  the  eye,  those  mys- 
terious changes  and  grades  of  development 
which  in  most  cases  are  accessible  only  at  par- 
ticular epochs,  or  are  wholly  concealed  during 
their  progress  in  the  hidden  recesses  of  the 
reproductive  organs,  or  whether  we  view  the 
modifications  which  they  present  of  the  respi- 
ratory and  other  important  functions  of  life,  it  is 
not,  perhaps,  saying  too  much  to  aver  that  there 
is  scarcely  any  class  of  animals  which  invites  the 
study  and  contemplation  of  the  lover  of  physi- 
ological science  by  phenomena  at  once  so  varied 
and  so  interesting  as  the  Amphibia. 

BIBLIOGRAPHY. — Boddaert,  Abhand.  von  Am- 
phibien,  in  Bcrl.  Gesels.  Naturf.  Freunde  B.  ii.  S. 
369.  Gray,  on  the  class  of  animals  called  by  Lin- 
naeus Amphibia.  Phil.  Trans.  1789,  p.  21.  Schnei- 
der, Amphib.  Physiol.  spec.  4to.  Frft.  a  M .  1790-92. 
Ditto,  Hist.  Amphib.  nat.  et  literar.  8vo.  Jena, 
1799-1801.  Laurenti,  Synops.  Reptil.  8vo.  Vim. 
1768.  Meyer,  Synops.  Reptil.  8vo.  Getting.  1795. 
Latreille,  Contin.  of  Buffon.  Hist.  Nat.  des  Am- 
phib. Ditto,  Hist.  Nat.  des  Salamandres,  8vo. 
Paris,  1800.  Brongniart.  Essai  d'une  Classif. 
Nat.  des  Reptiles.  'Societe  Philom.  A.  iii.  T.  2. 
Oppel,  Ord.  Fam.  u.  Gattung.  der  Amphibien.  4to. 
Munich.  1811.  Merrem,  Tent.  System.  Amphib. 
8vo.  Marb.  1820.  Roesel  von  Rosenhof,  Hist, 
nat.  Ranar.  nostrat.  fol.  Norib.  1746-61.  Ed.  Alt. 
auct.  germ.  s.  t.  Naturgesch.  der  Froesche,  &c. 
fol.  Niirnb.  1800-15.  Steinheim,  Entwickelung  d. 
Frosche.8vo.Hamb.  1820.  Hasselt,  Demctamorph. 


ANIMAL  KINGDOM. 


107 


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in  Appendices,  &c.  Ranur.  8vo.  Tubing.  1111. 
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1820.  Breyer,  Fabric.  Ranae  Pip*.  4to.  Bf-rl. 
1811.  KCotxe,  De  Rana  cornuta.  4io.  Berl.  1816. 
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De  Salamandr.  corp.  adip.  ovariis,  £c.  4to.  Berl. 
1818.  Rwconi,  Descr.  Anat.  delle  larve  (ielle  Sa- 
lamandre,  &c.  4to.  Pavia,  1817.  Ej.  Amours  des 
Salamandrcs  fol.  Milan.  1821.  Ej.  Develop,  du 
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(T.  Bell.) 

ANIMAL  KINGDOM,  an  appellation 
given  to  that  great  division  of  natural  bodies 
to  which  ANIMALS  belong.  Like  the  other 
kingdoms  of  nature,  the  mineral  and  the  vege- 
table, it  is  divided  into  numerous  sub-king- 
doms, classes,  orders,  genera,  and  other  subor- 
dinate groups,  according  to  the  properties  and 
forms  of  the  objects  which  it  comprehends. 
As  the  primary  grand  divisions  of  the  mineral 
kingdom  are  founded  on  the  primitive  forms  of 
crystallization,  and  those  of  the  vegetable  king- 
dom on  the  endogenous  and  exogenous  modes 
of  growth,  zoologists  have  endeavoured  to  find 
some  common  principle  for  their  first  divisions 
of  the  animal  kingdom.  The  most  common 
function  in  animals,  and  in  all  organized  beings, 
is  generation,  and  we  find  the  animal  kingdom 
divided  into  four  distinct  groups  by  the  modifi- 
cations of  this  function,  viz.,  jissipara,  gemmi- 
para,  ovipara,  and  vivipara.  But  as  the  fissi- 
parous  and  gemmiparous  modes  of  generation 
are  effected  without  the  presence  of  distinct 
permanent  organs,  as  the  fissiparous  mode 
occurs  in  isolated  species  belonging  to  classes 
remote  from  each  other  in  the  scale,  and  as 
nearly  all  the  classes  of  the  animal  kingdom 
belong  to  the  oviparous  division,  the  modifica- 
tions of  this  system  do  not  present  the  means 
of  establishing  primaiy  divisions  suitable  for 
the  purposes  of  zoology.  Although  the  pro- 
cess of  internal  digestion  is  not  so  universal 
as  the  function  of  generation,  the  internal 
alimentary  cavity  is  the  most  universal  organ 
of  animals,  and  its  forms  therefore  merit  a 
first  consideration  in  the  establishment  of  pri- 
mary groups.  It  is  found,  however,  that  in 
animals  whose  general  structure  is  nearly  the 
same,  the  alimentary  apparatus  varies  so  much 
according  to  the  nature  of  the  food,  as  to  render 
hopeless  any  attempt  to  subdivide  the  animal 
kingdom  from  its  modifications;  as  from  its 
having  one  or  two  apertures,  from  its  being 
a  simple  sac  or  a  lengthened  intestine,  from 
its  having  one,  two,  or  more  stomachs  or  glands 
developed  in  its  course,  or  other  modifications 
of  this  kind. 

In  the  circulating  system  we  are  presented 
with  better  means  for  such  divisions  than  in  the 
digestive,  for  the  radiated  classes  have  only 


vessels  for  their  circulation,  the  articulated 
classes  have  a  superadded  ventricle,  the  mollus- 
cous classes  and  fishes  a  bilocular  heart,  am- 
phibia and  reptiles  a  trilocular  heart,  and  the 
birds  and  mammalia  have  four  cavities  in  that 
organ.  The  respiratory  organs  likewise  afford 
the  means  of  founding  primary  divisions,  as 
into  ciliated,  branchiated,  and  pulmonated 
classes,  in  ascending  from  the  lowest  to  the 
highest  forms  of  that  system. 

The  primary  divisions  of  the  animal  kingdom 
adopted  by  Aristotle,  viz.,  animals  with  red 
blood  and  animals  without  red  blood,  are  ob- 
viously founded  on  a  single  principle  of  classi- 
fication, and  correspond  with  the  more  recent 
divisions  of  vertebrata  and  invertebrata ;  but 
from  the  number  of  distinct  classes  of  animals 
now  comprehended  under  each  of  these  divisions, 
they  are  quite  unsuitable  as  primary  groups  in 
the  present  advanced  state  of  the  science  of 
zoology.  Considering  the  functions  of  the 
nervous  system  or  the  intellectual  conditions  of 
animals  as  a  means  of  classification,  Lamarck 
proposed  three  great  divisions,  the  lowest  of 
which  comprehended  the  animals  regarded  by 
him  as  apatliic  or  automatic,  the  second  the 
sensitive,  and  the  highest  the  intelligent,  which, 
however,  are  too  hypothetical  to  answer  the 
purposes  of  the  zoologist.  Without  any  fixed 
principle  for  the  establishment  of  his  primary 
groups,  Cuvier  divided  the  animal  kingdom 
into  the  radiated,  the  articulated,  the  molluscous, 
and  the  vertebrated  divisions,  which  have  been 
generally  adopted  by  naturalists.  From  the 
importance  of  the  nervous  system  in  the  living 
economy  of  animals,  some  have  sought  in  its 
modifications  a  means  of  establishing  primary 
or  grand  divisions  of  the  animal  kingdom  on 
principles  more  uniform  and  philosophical  than 
those  commonly  employed.  In  the  radiated  or 
lowest  classes  of  animals,  wherever  the  nervous 
system  is  perceptible,  as  in  actinia,  medusa, 
beroe,  asterias,  echinus,  holothuria,  &c.  it  is 
found  in  the  form  of  filaments  disposed  in  a 
circular  manner  around  the  oral  extremity  of 
the  body.  This  lowest  form  of  the  nervous 
system  is  expressed  by  the  term  cyclo-neura, 
and  although,  like  the  radiated  and  every  other 
character  assigned  to  these  classes,  it  is  of 
partial  application,  it  marks  the  uniform  con- 
dition of  that  system  on  which  the  manifesta- 
tions of  life  are  chiefly  dependent,  and  which 
principally  establishes  the  relations  of  animals 
to  surrounding  nature.  A  different  form  of  the 
nervous  system  is  found  in  the  long  cylindrical 
trunks  of  the  helminthoid  and  entomoid  classes, 
where  we  observe  almost  from  the  lowest  ento- 
zoa  to  the  highest  Crustacea,  a  double  nervous 
chord  or  column  extending  along  the  whole  of 
the  ventral  surface  of  the  body.  This  form  of 
the  nervous  system,  common  to  the  articulated 
classes  of  animals,  is  expressed  by  the  term 
diplo-neura,  and  it  is  found  to  accompany  an 
organization  generally  more  complex  than  that 
of  the  cyclo-neurose  classes,  and  inferior  to  that 
of  most  of  the  succeeding  divisions  or  sub- 
kingdoms,  especially  in  the  organs  of  vegetative 
or  organic  life,  as  the  vascular,  the  digestive, 
and  the  glandular  apparatus.  The  nervous 


108 


ANIMAL  KINGDOM. 


system  is  more  concentrated  around  the  en- 
trance to  the  alimentary  canal  in  the  mollus- 
cous classes,  where  it  generally  forms  a  trans- 
verse series  of  ganglia,  disposed  around  the 
O3sophagus,  a  character  which  is  expressed  by 
the  term  cyclo-gangliata.  The  dorsal  position 
of  the  great  ganglia  and  nervous  columns  of 
the  cephalopods,  and  their  partial  protection  by 
an  organised  osseous  internal  skeleton,  leads  to 
the  condition  of  the  nervous  system  presented 
by  the  vertebrated  classes  of  animals,  where  its 
central  parts  are  in  the  form  of  a  lengthened  dorsal 
nervous  chord  developed  anteriorly  into  a  brain, 
and  protected  by  a  vertebral  column  and  cra- 
nium. The  vertebrated  classes  are  thus  de- 
signated spini-cerebrata,  from  the  form  of  the 
most  influential  part  of  their  organization. 

To  the  lowest  sub-kingdom  or  cyclo-neurose 
division  belong  five  classes  of  animals;  viz., 

1.  Polygastrica,  microscopic,  simple,  transpa- 

Fig. 


rent,  soft,  aquatic  animals,  in  which  no  nervous 
filament  has  yet  been  detected,  generally  pro- 
vided with  eyes,  with  a  circular  exsertile  dental 
apparatus  around  the  mouth,  and  with  vibratile 
cilia  for  respiration  and  progressive  motion, 
and  provided  with  numerous  internal  stomachs 
or  cceca  communicating  with  the  alimentary 
cavity.  (See  POLYGASTRICA.) 

2.  Porifera,  simple,  aquatic,  soft,  animals, 
without  perceptible  nervous  or  muscular  fila- 
ments or  organs  of  sense,  with  a  fibrous  internal 
skeleton  sometimes  supported  with  silicious  and 
sometimes  with  calcareous  spicula,  the  body 
permeated  with  a  soft  gelatinous  flesh,  covered 
externally  with  minute  absorbent  pores,  tra- 
versed by  numerous  ramified  anastomosing 
canals,  which  commence  from  the  pores  and 
terminate  in  large  open  vents,  as  seen  in  the 
annexed  figure  of  the  halina  pap'Ularis,  Gr. 
(Jig.  29),  which  represents  the  animal  as  alive, 
29. 


under  water,  with  the  usual  currents  passing 
inwards  through  its  pores  (a  a),  traversing  its 
internal  canals  (6),  and  escaping  by  the  larger 
vents  (c,  d.)  (See  PORIFERA.) 

3.  Polypifera,  aquatic  animals,  of  a  plant- 
like  form,  generally  fixed,  of  a  simple  internal 
structure,  for  the  most  part  without  perceptible 
nerves  or  muscles,  or  organs  of  sense,  and  nou- 
rished by  superficial  polypi,  which  are  developed 
from  the  fleshy  substance  of  the  body,  as  in  the 
campanularia  dichotoma,  (fig.  30),  wher^  the 

Fig.  30. 


irritable  fleshy  tubular  portion  of  the  animal  is 
seen  to  occupy  the  interior  of  the  base,  the 
stem,  and  the  branches,  and  to  extend  in  the 
form  of  polypi  from  the  open  terminal  cells. 
The  polypi  of  most  zoophytes  are  provided 
with  tentacula  around  their  orifice,  as  seen 
at  B,  (fig.  31),  and  the  margins  of  these  ten- 
tacula are  generally  furnished  with  numerous 
minute  processes,  termed  cilia,  (see  CILIA,)  by 
the  rapid  vibration  of  which,  currents  are  pro- 
duced in  the  surrounding  water  for  the  pur- 
pose of  attract- 
ing food  and 
of  aerating  the 
surface  and 
fluids  of  the 
body,  as  repre- 
sented in  fig. 
3,  A.  (See  PO- 
LYPIFERA.) 
4.  Acalepha,  soft  aquatic  free  animals,  of  a 
simple  structure,  generally  of  a  gelatinous  and 
transparent  texture,  and  emitting  an  acrid  se- 
cretion which  is  capable  of  irritating  and 
inflaming  the  skin  like  the  stinging  of  a  nettle, 
from  which  the  name  of  the  class  is  derived. 
They  rarely  possess  a  solid  skeleton  or  a  per- 
ceptible nervous  system.  They  are  all  marine, 
often  luminous,  sometimes  they  possess  eyes 
with  a  crystalline  humour,  they  feed  on  minute 
floating  animals,  and  swim  by  the  contractions 
of  a  highly  vascular  and  irritable  mantle  or  by 
means  of  air-sacs,  or  by  the  rapid  movement  of 


ANIMAL  KINGDOM. 


external  vibratile  cilia,  as  in  the  beroe  pileus 
represented  in  Jig.  32.     This  figure  represents 


Fig.  32. 


one  of  the  ciliograde  acalephae  in  which  the 
mouth  («)  is  directed  downwards,  and  leads,  by 
a  narrow  oesophagus,  to  a  wide  stomach  (6), 
and  from  this  the  intestine  proceeds  straight 
through  the  axis  of  the  body  to  the  anus  (c)  at 
the  opposite  pole.  The  longitudinal  nerves  (g), 
as  in  holothuria,  proceed  from  a  nervous  ring 
around  the  oesophagus.  The  ovaries  (d)  extend 
along  the  sides  of  the  intestine  ;  the  surface  of 
the  body  is  provided  with  eight  longitudinal 
bands  of  pectinated  broad  vibratile  cilia  (M), 
and  two  long  ciliated  tentacula  (Jf)  extend 
from  two  curved  lateral  sheaths.  (See  ACA- 

LEPH^l.) 

5.  Echinoderma,  simple  aquatic  animals, 
for  the  most  part  provided  with  a  calcified  ex- 
terior skeleton  or  a  coriaceous  skin,  the  body 
for  the  most  part  radiated,  globular,  or  cylin- 
drical, often  provided  with  a  distinct  nervous, 
muscular,  respiratory,  and  vascular  system. 
These  animals  have  received  the  names  of  echi- 
noderma,  from  the  spines  or  tubercles  which 
generally  cover  their  exterior  surface,  as  seen  in 
the  annexed  figure  of  the  echinus  esculentus 
(fig.  33.)  The  mouth  (6)  is  here  in  the  centre 


Fig.  33. 


of  the  lower  surface, 
and  the  intestine  (b,b.) 
connected  to  the  shell 
by  a  mesentery  (c),  on 
which  vessels  are  ra- 
mified, passes  in  a 
convoluted  manner 
upwards  to  the  oppo- 
site axis  where  the 
anal  aperture  (a)  is 
surrounded  by  the  five 
openings  of  the  ova- 
ries (d,d.}  The  mouth 
is  surrounded  with  a 
maxillary  apparatus 
containing  five  teeth, 
and  the  exterior  of  the 
complicated  and  solid 


shell  is  seen  to  be  provided  with  moveable  cal- 


--J 


109 


careous  spines.  These  animals  are  for  the  most 
pait  free,  but  some  are  fixed,  as  the  crinoid 
echinoderma,  the  vascular  system  is  unpro- 
vided with  auricle  or  ventricle,  and  the  diges- 
tive canal  is  seldom  furnished  with  distinct 
glandular  organs.  There  is  sometimes  a  simple 
stomach  with  one  aperture  and  numerous  late- 
ral cceca,  and  sometimes  a  lengthened  intestine 
with  two  terminal  openings.  Some  marine 
animals  without  an  echinodermatous  covering 
are  placed  in  this  class  from  the  similarity  of 
their  structure  in  their  more  essential  organs, 
as  is  the  case  with  the  holothuria  represented  in 
Jig.  34.  The  mouth  (a)  is  here  surrounded  with 
34  ramose  tenta- 

cula (c)  and 
an  osseous  ap- 
paratus. The 
intestine  is 
long,  convolu- 
ted, vascular, 
supported  by 
a  mesentery, 
and  termi- 
nates in  a 
cloaca  (i)  at 
the  opposite 
axis  of  the  bo- 
dy. The  rami- 
fied internal 
branchiae  (ff) 
open  from  the 
cloaca ;  the 
great  systemic 
artery  receives 
the  aerated 
blood  from  the 
branchiae,  and 
the  organs  of 
generation(wi) 
open  near  the 
anterior  part 
of  the  body. 
The  irritable  coriaceous  skin  is  supported  by 
five  broad  longitudinal  subcutaneous  muscular 
bands,  and  five  crowded  series  of  tubular  mus- 
cular feet  extend  from  its  surface.  (See  ECHI- 
NODERMA.) 

The    SECOND    SUB-KINGDOM    Or    DIPLO-NEU- 

ROSE  DIVISION  comprehends  four  classes  of 
helminthoid  animals  and  the  same  number  of 
entomoid  classes,  viz. 

6.  Entozoa,  parasitic, simple, internal,or  fixed 
animals,  for  the  most  part  of  a   lengthened 
cylindrical  form,  without    distinct  organs   of 
sense  or  any  internal  skeleton,  the  mouth  or 
anterior  part  of  the  body  generally  provided 
with  recurved  sharp  spines,  the  body  generally 
covered  with  an  elastic  white  transparent  inte- 
gument, the  nervous  system  seldom  distinct, 
the   vascular  system  without  auricle  or  ven- 
tricle, without  respiratory  organs,  and  with  the 
sexes  generally  separate.    (See  ENTOZOA  ) 

7.  Rotifera,  minute  aquatic  animals  with 
distinct  nervous  and  muscular  systems,  provided 
with  eyes,  lateral  maxillae,  a  dorsal  vessel,  an 
intestine  with  two  apertures,  and  with  vibratile 
cilia  disposed    generally  in  a  circular  form 


110 


ANIMAL  KINGDOM. 


around  the  anterior  part  of  the  body.  They 
are  termed  rotifera  from  the  appearance  of 
revolving  wheels  produced  by  the  rapid  move- 
ment of  the  cilia  disposed  around  the  mouth. 


One  of  these  minute  wheel-animalcules,  the 
hydatina  senta,  is  represented  highly  magnified 
in  Jig.  35,  where  the  mouth  (a)  is  surrounded 
with  long  vibratile  cilia  (b  6).  The  oesophagus 
(c)  leads  to  a  capacious  stomach  (d),  which 
becomes  a  narrow  intestine  below,  opening 
into  the  cloaca  (e),  where  the  genital  organs 
(i,i,g,g,h,)  also  terminate.  Several  ganglia 
surround  the  oesophagus,  and  a  dorsal  vessel 
(o  o)  is  seen  extending  along  the  middle  of  the 
back  and  sending  out  regular  transverse 
branches.  All  the  rotifera  are  free,  most  are 
naked,  many  are  sheathed  or  loricated,  they 
exhibit  no  branchial  or  pulmonary  organs,  they 
are  remarkable  for  their  fertility  and  their 
tenacity  of  life.  (See  ROTIFERA.) 

8.  Cirrhopoda,  aquatic,  articulated,  diplo- 
neurose  animals,  with  articulated  cirrhi,  and 
branchiae  for  respiration,  body  covered  with 
a  fleshy  mantle,  and  fixed  in  a  multivalve 
shell.  These  animals  are  all  marine,  the 
branchiae  are  fixed  to  the  bases  of  the  articu- 


lated cirrhi,  the  mouth  is  provided  with  man- 
dibles and  maxillae,  there  is  a  pulsating  dorsal 
vessel,  and  a  double  longitudinal  knotted  sub- 
abdominal  nervous  chord.  The  cirrhopoda  have 
been  commonly  placed  among  the  molluscous 
classes  from  the  form  of  their  exterior  coverings. 
(See  CIRRHOPODA.) 

9.  Annelida,  with  a  long  cylindrical  body 
generally  divided  into  transverse  segments,  and 
covered  with  a  soft  skin;  the  head  commonly 
provided  with  antennae  and  numerous  simple 
eyes,  and  the  mouth  with  maxilla? ;  the  organs 
of  motion  in  the  form  of  simple  seta?  or  cirrhi 
extending  from  the  sides  of  the  body  in  a  sin- 
gle or  double  row.  The  vascular  system  of 
the  annelida  consists  of  arteries  and  veins, 
without  a  distinct  auricle  or  ventricle,  and  the 
blood  is  generally  of  a  red  colour.  The  re- 
spiratory organs  are  generally  in  form  of  external 
branchiae,  sometimes  of  internal  air-sacs,  and 
the  alimentary  canal  passes  straight  through 
the  body  with  two  terminal  openings,  and  with 
numerous  lateral  coeca  developed  in  its  course, 
as  seen  in  that  of  the  leech,  hinido  mcdicinalis, 
Fig.  36.  (fig.  36.)  These  lateral  coeca  (b, 
f>  d>  e>f>  g>  h>  h  k,  m,}  increasing 
in  length  and  size  from  before 
backwards,  are  often  much  more 
lengthened  and  divided,  as  in  the 
halithea.  Many  of  the  red- 
blooded  worms  are  fixed  in  cal- 
careous, arenaceous,  or  other 
tubes,  and  many  are  free  and 
naked.  (See  ANNELIDA.) 

1 0.  Myriapoda,  with  a  length- 
ened articulated  body  equally 
developed  throughout ;  the  head 
provided  with  antennae  and  sim- 
ple eyes ;  the  segments  of  the 
trunk  free,  without  distinction 
of  thorax  and  abdomen;  the 
segments  furnished  with  one 
or  two  pairs  of  articulated  legs 
adapted  for  progressive  motion  on  land;  the 
respiration  is  aerial,  and  performed  by  trachea?, 
which  ramify  from  their  commencement  in 
stigmata  which  open  along  the  whole  extent 
of  the  body.  They  do  not  undergo  me- 
tarmorphosis,  nor  possess  compound  eyes  nor 
wings,  and  they  have  always  more  than  six 
pairs  of  feet.  (See  MYRIAPODA.) 

1 1 .  Insecta,  with  six  articulated  legs  extend- 
ing from  an  articulated  trunk,  which  is  divided 
into  a  head,  thorax,  and  abdomen ;  the  head  is 
provided  with  a  labium,  a  labrum,  mandibles, 
and  maxillae,  with  compound  and  often  also 
with  simple  eyes,  and  a  pair  of  antennae  and 
palpi ;  the  thorax  supports  the  six  legs,  and 
commonly  one  or  two  pairs  of  wings,  and  has 
attached  to  it  the  moveable  segments  of -the 
abdomen,  which  embrace  the  principal  organs 
of  digestion,  circulation,  and  generation.  The 
respiration  is  effected  by  tracheae,  which  form 
continuous  lateral  trunks  before  they  ramify 
through  the  body.  The  circulation  is  aided  by 
a  pulsating  dorsal  vessel  provided  with  nu- 
merous valves,  and  the  alimentary  canal  is 
furnished  with  salivary  and  hepatic,  and  often 
with  pancreatic  glands.  The  sexes  are  sepa- 


ANIMAL  KINGDOM. 


Ill 


rate,  and  the  genital  organs,  slow  in  their 
development,  are  highly  complicated  in  the 
perfect  state.  These  animals  generally  pass 
through  a  series  of  metamorphoses,  and  throw 
off  their  exuvial  covering  five  or  six  times 
during  their  development.  This  class  is  the 
most  numerous  in  the  animal  kingdom,  com- 
prehending about  a  hundred  thousand  species. 
The  greater  part  of  their  life  is  spent  in  the 
larva  state,  during  which  they  are  generally  most 
voracious,  like  the  young  of  other  classes.  In 
the  adult  state  the  masticating  organs  and  the 
digestive  apparatus  vary  much  according  to 
the  kind  of  food  in  the  different  species,  as  is 
seen  in  comparing  the  alimentary  canal  of  a 
carnivorous  cicindela  campestris  (Jig'  37.)  with 

Fig.  37. 


Fig.  38. 


that  of  a  phytophagous  melolontha  vulgaris, 
(fig.  38.)  In  the  carnivorous  insect  (Jig.  37.) 
the  intestine  passes  nearly  straight  through  the 
body  with  few  enlargements  in  its  course,  and 
the  glandular  organs  have  a  simpler  struc- 
ture. The  oesophagus  passes  down  narrow 
from  the  head,  and  dilates  into  a  wide  glandu- 
lar crop  (a),  which  is  succeeded  by  a  minute 
gizzard,  and  this  is  followed  by  the  chylific 
stomach  (6,r),  which  is  covered  like  the  crop 
with  minute  glandular  cryptae  or  follicles.  At 
the  pyloric  extremity  of  the  chylific  stomach,  the 
liver,  in  form  of  simple  biliary  ducts,  pours  its 
secretion  into  that  cavity  by  two  orifices  on  each 
side  (</)•  The  short  small  intestine  (e}  opens  into 
a  wide  colon  (J'\  which  terminates  in  the  anus 
(g).  In  the  vegetable-eating  insect,  {fig.  38) 
the  alimentary  canal  is  more  lengthened,  con- 
voluted, and  capacious,  with  more  numerous 
dilatations,  and  the  glandular  organs  are  more 
developed.  The  crop  (a)  of  the  melolontha  is 


succeeded  by  a  minute  rudimentary  gizzard,  and 
to  this  succeeds  a  long  and  sacculated  glandu- 
lar or  chylific  stomach,  which  becomes  narrow 
and  convoluted  below,  and  terminates  in  a 
small  pyloric  dilatation,  which  receives  the 
four  terminations  of  the  biliary  organs.  The 
succeeding  part  of  the  intestine  is  also  con- 
voluted, and  has  three  enlargements  in  its 
course  to  the  anus  (e).  The  liver  (c  c)  is 
here  of  great  magnitude,  and  has  its  secreting 
surface  much  extended  by  the  development  of 
innumerable  minute  coaca  from  its  primary 
ducts.  Insects  also  often  present  distinct 
urinary  organs,  and  numerous  glands  in  both 
sexes  connected  with  the  organs  of  generation. 
(See  IKSECTA.) 

12.  Arachnida,  with  the  head  and  thorax 
united,  generally  four  pairs  of  legs  ;  with- 
out antenna,  or  compound  eyes,  or  wings, 
or  metamorphosis  ;  the  trunk  divided  into  a 
cephalo-thorax  and  abdomen ;  the  head  is  often 
provided  with  two  pairs  of  chiliform  manduca- 
tory organs  ;  the  eyes  are  simple.  The  respi- 
ration is  aerial,  sometimes  performed  by  tra- 
chea, and  sometimes  by  pectinated  pulmonary 
sacs  opening  on  the  sides  of  the  abdominal 
surface  of  the  trunk.  In  their  nervous,  res- 
piratory, and  circulating  systems  they  indicate 
a  higher  grade  of  development  than  insects, 
and  like  them  are  generally  inhabitants  of  the 
land,  attaining  considerable  size  and  strength, 
with  cunning,  cruel,  carnivorous  habits,  and 
often  provided  with  poisonous  instruments. 
(See  ARACHNIDA.) 

13.    Crustacea,   with  the  head  and   thorax 
generally  united,  two  pairs  of  antennae,  two 


112 


ANIMAL  KINGDOM. 


compound  eyes,  more  than  four  pairs  of  legs, 
the  respiration  effected  by  gills,  and  the  shell 
generally  hard  and  calcareous.  These  ento- 
moid  aquatic  animals  are  generally  carnivorous, 
and  have  a  short  and  straight  alimentary  canal. 
Their  circulating  system  is  often  aided  by  a 
muscular  ventricle.  l"he  sexes  are  separate, 
and  the  organs  of  generation  are  double  and 
symmetrical  in  both  sexes.  Their  biliary  or- 
gans have  a  conglomerate  form,  being  com- 
posed of  minute  glandular  follicles  grouped 
together  into  lobules  and  larger  lobes.  Some 
of  these  animals  are  fixed  and  parasitic,  and 
breathe  by  their  general  exterior  surface ;  most 
are  free,  and  respire  by  means  of  branchiae 
placed  under  the  sides  of  the  carapace  or  ex- 
posed on  the  under-surface  of  the  post-abdomen. 
(See  CRUSTACEA.) 

The  THIRD,  or  CYCLO-GANGLIATED  or  mol- 
luscous DIVISION  of  the  animal  kingdom,  com- 
prehends five  classes,  viz. : — 

14.  Tunicata,  soft,  aquatic,  acephalous 
animals,  breathing  by  internal  branchiae,  never 
in  form  of  four  pectinated  laminae,  and  covered 
by  a  close  external  elastic  tunic  furnished  with 
at  least  two  apertures.  The  exterior  tunic  is 
lined  by  a  muscular  coat ;  sympathetic  ganglia 
are  observed  in  the  abdominal  cavity,  and  the 
respiratory  organs  are  ciliated  as  in  higher 
molluscous  classes  for  the  production  of  the 
respiratory  currents.  The  mouth,  unprovided 
with  tentacula  or  other  organs  of  sense,  opens  at 
the  bottom  of  the  abdominal  cavity,  as  seen  in  the 
cynthia  dione.  (Fig.  39.  a.)  The  short  oesopha- 

Flg.  39. 


tral  orifice  (</)  of  the  sac,  where  it  terminates 
in  the  anus  (c).  The  thoracic  orifice  (e),  or  the 
entrance  to  the  respiratory  cavity,  is  generally 
provided  with  numerous  delicate  tentacula  (y), 
and  a  nervous  longitudinal  filament  (A)  is  ge- 
nerally observed  to  encompass  that  opening,  and 
to  terminate  in  a  small  glanglion  (g).  These  ani- 
mals are  entirely  marine,  most  are  fixed,  some 
are  free ;  they  are  all  female,  like  the  conchifera ; 
the  circulation  is  aided  by  a  muscular  heart. 
Many  are  organically  connected  in  groups, 
others  are  isolated,  (See  TUNICATA.) 

15.  Conchifera,  acephalous,  aquatic  ani- 
mals, covered  with  a  solid  calcareous  shell, 
consisting  of  at  least  two  pieces,  and  breathing 
by  internal  branchiae  in  form  of  four  pectinated 
laminae.  These  bivalved  animals  have  the 
mouth,  as  in  the  former  class,  situated  at  the 
bottom  of  the  respiratory  or  thoracic  cavity ; 
the  stomach  is  surrounded  and  perforated  by 
the  lobes  of  the  liver ;  the  circulation  is  aided 
by  a  bifid  or  a  divided  auricle  and  by  a  mus- 
cular ventricle,  which  is  generally  perforated 
by  the  rectum,  as  seen  in  the  annexed  figure  of 
the  organs  of  the  spondylus,  (Jig.  40.)  The 

ibrU 


Fig.  40. 


gus  leads  to  a  capacious  stomach  (6),  sometimes 
surrounded  by  the  lobes  of  a  small  liver,  which 
pours  its  secretion  into  that  cavity  as  in  higher 
mollusca.  From  the  stomach  a  short  wide 
convoluted  intestine  proceeds  to  near  the  ven- 


two fimbriated  lips 
(a)  which  surround 
the  mouth  are  pro- 
longed laterally  into 
four  tapering  flat  pec- 
tinated tentacular  ex- 
pansions (b).  The 
-stomach  (c)  and  the 
intestine  are  sur- 
rounded by  the  large 
mass  of  the  liver  (i), 
and  the  rectum,  near 
the  adductor  muscle 
(m),  penetrates  the 
ventricle  of  the  heart 
(d),  at  some  distance 
from  the  anus  (ej. 
The  branchial  veins 
(g,  h)  return  the 
aerated  blood  to  the 
two  lateral  divisions 
of  the  auricle,  these 
pour  it  into  the  ventri- 
cle, by  which  it  is  pro- 
pelled forwards  and 
backwards  through 
the  system,  so  that  the  heart  is  here,  as  in 
other  invertebrated  classes,  a  systemic  organ. 
(See  CONCHIFERA.) 

16.  Gasteropoda,  body  invertebrate  and  in- 
articulate, provided  with  a  head  which  for  the 
most  part  supports  tentacula  and  simple  eyes, 
and  furnished  with  a  muscular  foot,  extended 
under  the  abdomen,  and  adapted  for  creeping. 
These  animals  are  sometimes  naked,  more 
generally  covered  with  a  univalve,  unilocular, 
solid,  external  shell.  Some  gasteropods  breathe 
by  a  pulmonary  cavity,  most  by  branchiae  va- 
riously disposed  on  the  surface  or  under  an 
open  mantle.  Most  are  marine,  many  inhabit 
fresh  waters,  and  some  reside  on  land.  The 
higher  forms  are  mostly  carnivorous,  and  the 
lower  orders  phytophagous,  and  this  difference 
affects  principally  their  alimentary  apparatus, 


ANIMAL  KINGDOM. 


113 


as  seen  by  comparing  that  of  the  carnivorous 
buccinum  undatwH,   (fig-  41,)  with  the   same 


Fig.  41 


apparatus  in  the  phytophagous  patella  vulgata, 
fjig.  42.)  Like  most  of  the  predaceous  gas- 
teropods  the  buccinum  is  provided  with  a  long 
muscular  proboscis,  (Jig.  41,  o,  b,)  capable  of 
being  extended  to  a  distance  from  the  mouth, 
and  enclosing  a  bifid  tongue  covered  with  sharp 
recurved  teeth.  The  oesophagus  near  the  sto- 
mach dilates  into  a  small  crop  (c),  and  to  this 
succeeds  a  round  membranous  stomach  (d,  e}. 
The  whole  remaining  intestine  is  shorter  than  the 
oesophagus,  and  dilates  into  a  wide  colon  (J',~) 
before  terminating  in  the  anus  (g),  on  the  right 
side  of  the  body  under  the  open  mantle.  The 
liver,  of  great  size,  and  accompanying  the 
testicle  (i)  in  the  turns  of  the  spire,  pours 
its  secretion  into  the  stomach  as  in  the  acepha- 
lous classes.  The  vas  deferens  following  the 
right  side  of  the  body  terminates  at  the  end  of 
the  male  organ  (A)  in  a  small  tubular  styliform 
duct.  In  the  patella,  (Jig.  42,)  however,  which 
feeds  on  marine  plants, the  mouth  (a)  is  provided 
with  a  long  slender  convoluted  tongue  covered 
with  numerous  rows  of  teeth  like  a  long  file. 
The  wide  and  sacculated  oesophagus  (rf)  leads 
to  a  capacious  and  lengthened  stomach  (J\  g\ 
surrounded  by  the  large  liver,  and  the  long 
convoluted  intestinal  canal  (A)  makes  several 
turns  imbedded  in  the  mass  of  the  liver  before 
it  arrives  at  the  short 
Fig.  42.  dilated  rectum  (i) 

and  anus  (/c).  The 
salivary  glands  are 
generally  of  great 
size  in  this  class, 
and  present  some- 
times in  the  same 
species  both  the 
simple  follicular 
and  the  conglome- 
rate forms.  The 
pancreas  likewise  is 
often  present  in  form 
of  a  single  follicle 
opening  into  the  sto- 
mach along  with  the 
biliary  ducts.  The 
inferior  orders  are  mostly  male  and  female,  but 

VOL.    I. 


in  the  higher  forms  the  sexes  are  distinct.    (See 
GASTEROPODA.) 

17.  Pteropotldj  body  organized  for  swim- 
ming, mantle  closed  above,  branchiae  external, 
no  muscular  foot  for  creeping,  shell,  when 
present,  always  thin,  pellucid,  unilocular,  and 
inoperculate.  These  soft,  minute,  floating  ani- 
mals are  all  marine,  and  are  enabled  to  swim 
by  means  of  two  lateral  musculo-cutaneous  fin- 
like  expansions,  on  the  surface  of  which  the 
respiratory  branchiae  or  vascular  plexuses  are 
placed.  These  lateral  fins  are  never  supported 
by  rays.  The  head  is  generally  provided  with 
retractile  or  sheathed  tentacula,  seldom  with 
eyes.  The  body  is  sometimes  entirely  naked, 
often  protected  by  a  delicate  thin  transparent 
shell,which  encloses  the  abdomen  and  is  covered 
with  a  fold  of  the  skin.  They  appear  to  be  most 
closely  allied  to  the  inferior  testaceous  cepha- 
lopods  in  the  nature  and  form  of  their  shells 
and  in  their  locomotive  powers,  and  also  in 
the  general  simplicity  of  their  internal  struc- 
ture, especially  of  their  generative  organs.  The 
structure  of  one  of  the  naked  pteropods,  clio 
borealis,  is  represented  in  Jig.  43,  where  the 
abdominal  cavity  is  exposed  by  the  mantle 

Fig.  43. 


being  opened  from  behind.  The  mouth  (a) 
leads  to  a  long  oesophagus  (6),  which  is  sur- 
rounded by  a  circular  series  of  nervous  gan- 
glia (t).  The  stomach  (c  c)  is  imbedded  in  the 
lobes  of  the  liver  (g),  which  open  by  numerous 
short  ducts  into  its  cavity.  The  oesophagus  is 
accompanied  by  the  two  long  simple  salivary 
follicles  (/c),  and  at  the  left  or  pyloric  extremity 
(d}  of  the  stomach  is  placed  the  heart  (i},  en- 
closed in  its  pericardium,  which  receives  the 
arterialized  blood  from  the  branchial  veins,  and 
sends  it  through  the  system.  The  bottom  of 
the  abdomen  or  cavity  of  the  mantle  (A)  is 
occupied  as  in  the  cephalopods  with  the  gene- 
rative organs,  which  consist  of  an  ovary  (/) 
and  long  oviduct  (m,  o),  into  which  a  short 
wide  coecum  (n),  commonly  considered  as  a 
testicle,  pours  its  secretion.  The  oviduct  termi- 
nates on  the  left  side,  near  the  anus  (e)y  in  a 
small  glandular  sac  (<?),  beneath  which  is  the 
rhenal  sac  (p}.  The  pteropods  are  commonly 
found  floating  in  immense  numbers  at  the  sur- 


114 


ANIMAX  KINGDOM. 


fare  of  the  water  in  still  warm  evenings  in 'tro- 
pical seas ;  some,  as  the  clio  borealis,  figured 
above,  abound  in  the  Arctic  seas.  (See  PTE- 
ROPODA.) 

18.  Cephalopoda,  free  cyclo-gangliated  or 
mulluscous  animals,  with  the  feet  disposed 
around  the  head,  respiring  by  internal  branchiae, 
and  with  the  abdominal  cavity  enveloped  by  a 
muscular  mantle  open  anteriorly.  The  cepha- 
lopods  are  all  marine  animals  capable  of  swim- 
ming by  means  of  membranous  or  muscular 
expansions,  which  are  never  supported  by  rays. 
The  surface  of  the  body  is  often  naked,  some- 
times covered  with  a  shell,  which  is  generally  po- 
lythalamous,  rarely  monothalamous,  and  always 
inoperculate.  There  is  often  a  concealed,  loose, 
dorsal,  calcareous  or  horny  shell  contained  in  a 
shut  subcutaneous  sac.  The  mouth  is  fur- 
nished with  two  horny  or  calcified  mandibles, 
and  the  rudiments  of  an  internal  organized 
cartilaginous  cranium  and  vertebral  column  are 
generally  perceptible,  together  with  some  de- 
tached parts  of  the  skeleton  of  vertebrata.  The 
oesophagus  is  surrounded  by  a  nervous  collar, 
from  which  two  supra-abdominal  nervous  co- 
lumns generally  extend  along  the  middle  of  the 
back,  and  sympathetic  ganglia  are  observed  in 
the  abdominal  cavity  as  in  the  inferior  mollus- 
cous classes.  These  are  predaceous  animals, 
and  the  alimentary  canal,  though  generally 
furnished  with  three  enlargements,  forming  a 
crop,  a  gizzard,  and  a  spiral  or  proper  chylific 
stomach,  is  always  very  short.  There  are  two 
pairs  of  salivary  glands;  the  liver  is  of  great 
size,  and  pours  its  secretion,  with  that  of  the 
pancreatic  follicles,  into  the  stomach,  as  in  the 
inferior  classes.  There  is  always  a  strong  mus- 
cular systemic  ventricle,  and  generally  a  di- 
vided auricle  placed  at  the  beginning  of  the 
branchial  arteries.  The  common  form  of  the 
chylopoietic  organs  is  seen  in  those  of  the 
loligopsis  guttata,  (jig.  44,)  where  the  liver 

(a    a    a    a) 


Fig.  44. 


pours  its  se- 
cretion by 
ducts  (b), 
which  are 
surrounded 
and  pene- 
trated by 
the  pancrea- 
tic follicles 
(c  c),  and 
which  unite 
into  a  single 
canal  before 
they  open  by 
a  valvular 

aperture  into  the  third  or  chylific  stomach  (fg). 
The  crop  (d)  ends  in  the  strong  muscular  giz- 
zard (e},  and  from  the  third  stomach  (,/'g)  the 
short  intestine  (A)  ascends  in  front  of  the  livev 
to  terminate  by  a  valvular  anus  at  the  base  of 
the  funnel.  The  naked  species  have  a  glandu- 
lar sac  for  secreting  a  black  inky  matter,  which 
appears  to  be  wanting  in  those  protected  by  an 
external  shell,  excepting  in  the  argonauta, 
where  the  shell  is  seen  in  the  ovum,  and  where 
there  is  a  slight  membranous  connexion  be- 


tween the  animal  and  its  thin  delicate  calca- 
reous covering.  The  sexes  are  generally  sepa- 
rate, but  the  lowest  foraminiferous  cephalo- 
pods  appear  to  approach  to  the  pteropods  in 
the  male  and  female  character  of  the  genital 
organs.  (See  CEPHALOPODA.) 

The  last  or  highest  DIVISION  of  the  animal 
kingdom,  comprehending  the  vertebrated  or 
red-blooded  animals,  or  SPINI-CEREBRATA, con- 
sists of  five  distinct  classes,  characterised  chiefly 
by  their  generative,  their  sanguiferous,  and 
their  tegumentary  organs,  viz. — 

19.  Pisces,  cold  and  red-blooded  oviparous 
vertebrated  animals,  with  one  auricle  and  one 
ventricle  to  the  heart,  breathing  by  permanent 
branchiae,  and  with  fins  for  progressive  motion. 
They  have  a  vertebral  column  and  cranium, 
enclosing  a  spinal  cord,  and  brain  consisting 
of  a  medulla  oblongata,  optic  lobes,  cerebral 
hemispheres,  olfactory  tubercles,  and  a  cere- 
bellum. The  hands  and  feet  are  always  formed 
like  fins  for  progressive  motion  in  a  watery 
element.  The  fins  are  supported  by  rays  pro- 
longed from  the  skeleton,  the  body  is  generally 
covered  with  scales,  the  trunk  is  organized 
for  the  lateral  motion  of  the  tail,  there  is 
no  sacrum,  and  the  pelvic  arch  is  unconnected 
with  the  vertebral  column.  The  bones  are 
elastic  or  cartilaginous,  and  the  centres  of 
ossification  for  the  most  part  remain  perma- 
nently detached.  The  bodies  of  the  vertebrae 
terminate  in  two  cup-like  cavities,  they  move 
on  elastic  tense  intervertebral  sacs,  and  the 
transverse  processes  are  directed  vertically 
downwards  in  the  coccygeal  region  of  the 
skeleton  to  facilitate  the  lateral  motion  of  the 
trunk.  The  muscles,  of  a  white  colour,  are 
disposed  in  oblique  strata  on  the  sides  of  the 
trunk  for  the  movement  of  the  elastic  vertebral 
column.  The  mouth,  destitute  of  salivary 
glands,  is  generally  furnished  with  numerous 
unequal,  irregular,  fangless,  osseous  teeth,  and 
the  wide  oesophagus,  short  like  the  neck,  leads 
to  a  capacious  stomach,  from  which  the  in- 
testine, shorter  than  in  the  higher  classes,  and 
nearly  equal  throughout,  proceeds,  without 
ccecal  enlargement,  to  terminate  in  a  cloacal 
sac  on  the  inferior  surface  of  the  trunk.  The 
liver  is  large,  and  pours  its  secretion  generally 
by  a  single  duct  into  the  duodenum,  near  the 
pyloric  extremity  of  the  stomach  and  close 
to  the  opening  of  the  pancreatic  duct,  as  shown 
in  the  annexed  figures  of  these  parts  in ,  the 
frog-fish  (Jig.  45,  A)  and  the  cod  (Jig.  45,  B). 
The  oesophagus  (a)  of  the  frog-fish  (Jig  45,  A) 
leads  to  a  large  globular  stomach  (c)  with  a 
strong  muscular  cardiac  sphincter  (b}.  The 
pyloric  extremity  is  also  surrounded  with 
strong  muscular  bands  (d),  and  beyond  its 
pyloric  valve  two  pancreatic  simple  glandular 
follicles  (ee)  open  into  the  duodenum  (g)  close 
to  the  opening  of  the  ductus  communis  chole- 
dochus  {/).  In  the  cod  (  fig.  45,  B)  the  wide 
oesophagus  (a)  leads  to  a  long  and  capacious 
muscular  stomach  shut  below,  and  immediately 
beyond  the  pyloric  valve,  formed  by  a  circular 
fold  of  the  mucous  coat,  open  the  ducts  of 
numerous  straight  and  simple  pancreatic  folli- 


ANIMAL  KINGDOM. 


Fig.  45. 


cles  (e  e)  along  with  the  ductus  coramunis 
choledochus  (f)-  The  cartilaginous  plagi- 
ostome  fishes,  the  most  complicated  of  this 
class,  have  a  conglomerate  form  of  the  pan- 
creas opening  in  the  same  situation.  In  the 
sturgeon  and  in  the  sword-fish  an  interme- 
diate form  is  seen  between  the  simple  pan- 
creatic follicles  of  the  invertebrated  classes 
and  the  more  complicated  conglomerate  organ 
in  the  higher  vertebrata.  This  is  shown  in 
the  annexed  figure  of  the  chylopoietic  viscera 
as  I  found  them  in  the  xiphias  gladius  (Jig. 
46),  where  the  liver  (a)  is  raised  up  "to  show 

Fig.  46. 


the  three  hepatic  ducts  uniting  with  the  cystic 
from  the  curved  gall-bladder  (c)  to  form  a  very 
short  ductus  communis  choledochus.  The 
pancreas  (c?)  forms  a  large  reniform  mass  com- 

red  of  numerous  straight  follicles  produced 
a  the  successive  divisions  of  the  great  termi- 
nal duct  (e)  of  this  organ.  This  large  inter- 
mediate organ  is  surrounded  with  a  distinct 
muscular  tunic  to  force  its  contents  into  the 
duodenum  immediately  beyond  the  pyloric 
valve  (b}.  The  tortuous  small  intestine  ends 
by  a  valvular  orifice  (/)  in  a  very  short  but 
distinct  colon,  which  presents  no  coecum  in  its 
course  to  the  anus  (g).  The  bilocular  heart 


115 

of  fishes  is  entirely  branchial;  it  is  often  pre- 
ceded by  a  sinus  vcnosw,  and  is  always 
succeeded  by  a  bulbus  arteriosus,  which  often 
presents  numerous  internal  valves  in  its  course. 
The  venous  blood  is  entirely  sent  through  the 
gills,  and  the  branchial  veins,  after  giving 
branches  to  the  anterior  parts,  unite  to  form 
the  aorta  which  sends  the  arterialised  blood 
through  the  rest  of  the  system  without  the  aid 
of  a  systemic  heart.  The  respiration  is  effected 
by  the  transmission  of  water  through  the  mouth 
or  through  distinct  spiracula,  and  over  the 
surface  of  the  branchiae,  which  are  internal  in 
the  adult,  and  are  often  preceded  by  external 
branchiae  in  the  young.  The  lungs  are  always 
rudimentary,  when  present,  sometimes  in  form 
of  a  shut  single  air-bag,  sometimes  divided 
or  ramified,  and  most  generally  communicating 
by  a  ductus  pneumatic  us  with  the  intestine  or 
stomach,  or  oesophagus,  but  seldom  employed 
for  respiration.  Fishes  are  oviparous  and  have 
the  sexes  separate ;  the  ovaries  are  continuous 
with  the  oviducts  in  osseous  fishes,  and  de- 
tached from  them  in  the  plagiostome  chon- 
dropterygii,  and  impregnation  sometimes  takes 
place  internally  and  sometimes  after  the  ova 
are  separated  from  the  body.  (See  PISCES.) 

20.  Amphibia,  cold  and  red-blooded,  verte- 
brated,  oviparous  animals,  with  three  cavities  of 
the  heart,  with  a  naked  skin,  and  breathing,  in 
the  young  state,  by  gills.     These  animals  com- 
mence their  career  like  fishes  with  one  auricle 
and  one  ventricle,  which  send  the  whole  of  the 
blood  through  the  branchiae,  and  they  have  at 
this  period  also  double  concave  bodies  of  the 
vertebrae,  as  in  fishes.     Many  retain  the  gills 
through  life,  accompanied  with  pulmonic  cavi- 
ties, from  which  the  arterialised  blood  is  sent  to 
a  small  left  auricle.     These  animals  are  termed 
amphibia  from  the  metamorphosis  to  a  terres- 
trial from  an  aquatic  life  seen  in  most  of  the 
species.     Their   skeleton   is   imperfectly   con- 
solidated, their  ribs  very  short  or  wanting,  their 
pelvic  arch  free  or  nearly  so,  and  their  atlantal 
and   sacral   extremities  often  very  imperfectly 
developed  or  partly  deficient.     Their  toes  are 
destitute  of  claws,  as  their  skin  is  of  scales, 
and  the  respiration  through  their  naked,  highly 
sensitive,  and  secreting  surface  compensates  for 
the  imperfect  development  or  limited  use  of 
their  lungs,  especially    during  submersion  or 
hybernation.     Some   reside   constantly  in  the 
water,  others  occasionally,  and  others  continue 
on  land.     The  male  organ  of  intromission  is 
rarely  developed,  and  impregnation  of  the  ova 
is  generally  effected   externally.    The  genital 
organs  are  double  and  symmetrically  developed 
in  both  sexes.     The  perennibranchiate  amphi- 
bia, especially  the  axolotl,  have  been  shown  by 
Weber  to  possess  a   double  auricle    like  the 
caducibranchiate  species.     (See  AMPHIBIA.) 

21.  Reptilia,  cold  and  red-blooded,  ovipa- 
rous, vertebrated  animals,  with  two   auricles 
and   one  ventricle,   not  breathing  by  gills  in 
their  young  state,  covered  with  scales,  and  with 
the   means   of  internal  impregnation.     These 
animals,  whether  aquatic  or  terrestrial,  breathe 
only  by  means  of  lungs,  and  their  pulmonic 
respiration  and  the  left  auricle  of  the  heart  are 

j  2 


116 


ANIMAL  KINGDOM. 


greater  than  in  the  amphibia.  Their  bones  are 
more  consolidated  than  in  the  lower  vertebrata, 
their  pel  vie  arch,  when  developed,  is  more  firmly 
attached  to  the  vertebral  column,  the  centres  of 
ossification,  especially  of  the  cranial  bones, 
generally  remain  detached,  the  extremities  are 
for  the  most  part  more  competely  developed, 
and  the  toes  are  generally  provided  with  claws. 
Their  cerebellum  is  remarkably  small,  their 
muscular  irritability  languid,  and  they  have 
great  tenacity  of  life.  This  ventricle,  which 
receives  both  the  venous  and  arterialised  blood, 
is  more  or  less  divided  by  an  ascending  imperfect 
septum.  The  thoracic  and  abdominal  cavities 
are  not  separated  by  a  muscular  diaphragm, and 
the  lungs  extend  backwards  over  the  abdominal 
viscera.  Their  organs  of  generation  are  double 
in  both  sexes,  and  symmetrically  developed  on 
the  two  sides  of  the  body.  The  two  portions 
of  the  corpus  cavernosum  are  often  detached 
and  bifid ;  the  chorion  of  the  ova  is  generally 
thin  or  coriaceous,  seldom  calcified  or  hard, 
and  the  instincts  of  the  parent  generally  extend 
to  the  protection  of  the  young.  (See  REPTILIA.) 
22.  Aves,  warm  and  red-blooded,  ovipa- 
rous, vertebrated  animals,  with  four  cavities  of 
the  heart,  covered  with  feathers,  and  with  their 
arms  organized  for  flight.  Their  bones  are  the 
most  compact  and  dense  in  texture,  the  most 
extensively  anchylosed,  and  generally  contain 
air  admitted  from  the  cells  of  the  lungs.  Their 
tympanic  bone  is  moveable,  they  have  horny 
mandibles  in  place  of  teeth,  their  coracoid 
bones  reach  the  sternum,  the  sternal  ribs  are 
ossified,  and  they  want  the  tarsal  bones.  Their 
diaphragm  never  forms  a  complete  partition 
between  the  thoracic  and  abdominal  cavities. 
The  hemispheres  of  the  brain  are  without  con- 
volutions, the  optic  lobes  are  large  and  hollow, 
the  cerebellum  is  large  and  sulcated,  and  the 
posterior  enlargement  of  the  spinal  chord  of 
great  size.  The  great  irritability  of  their  mus- 
cular system  corresponds  with  the  great  extent 
of  their  respiration,  the  high  development  of 
their  nervous  system,  the  rapidity  of  their  cir- 
culation, and  the  increased  energy  of  all  their 
functions.  Their  alimentary  canal  is  furnished 
with  a  crop,  a  glandular  infundibulum,  a  giz- 
zard, and  generally  with  two  cceca-coli,  as  seen 
in  the  annexed  diagram  (Jig.  47),  showing  the 

Fig.  47. 


common  form  of  these  parts  in  a  gallinaceous 
bird.  In  these  gallinaceous  birds  the  oesopha- 
gus (a)  sends  out  at  a  right  angle  with  its 
course  a  large  crop  (6),  with  a  contracted 
neck,  and  supplied  with  glandular  follicles. 
Beneath  this  is  the  infundibulum  or  glandular 
stomach  (c),  with  numerous  large  follicles 
placed  between  the  mucous  and  muscular 
coats,  and  this  opens  into  the  large  muscular 
gizzard  (d*),  provided  externally  with  two  strong 
digastric  muscles  (e}.  The  cardiac  and  py- 
loric  orifices  of  the  gizzard  are  close  to  each 
other  (/),  and  towards  the  lower  part  of  the 
small  intestine  a  minute  coecum  often  indi- 
cates the  original  entrance  of  the  yolk-bag. 
The  two  long  cceca-coli  (g)  commence  by  nar- 
row entrances  (A),  and  the  short  colon  ends 
in  a  common  cloaca  (/)  for  the  genital  arid 
urinary  secretions. 

Inthepredaceous  birds,  as  the  eagles  (figAQ), 
the  oesophagus  («),  the  crop  (6),  the  infundibu- 
lum (c),  and  the  gizzard  (de\  are  capacious,  thin, 

Fig.  48. 


and  membranous,  and  form  a  continuous  cavity 
for  the  prey,  from  which  the  indigestible  parts 
can  be  thrown  out  in  a  bolus.  In  these  birds 
the  cceca-coli  (g)  are  very  small,  sometimes 
unequal,  or  wanting.  The  urinary  («)  and 
genital  organs  (kk)  enter  the  cloaca  (/)  near 
the  anus.  The  right  ventricle  of  birds  has  the 
tricuspid  valve  in  form  of  a  thick  strong  mus- 
cular fold,  and  the  aorta  descends  on  the  right 
side.  The  lungs  form  two  undivided,  light- 
coloured  lobes,  fixed  by  pleurae  to  the  back  part 
of  the  trunk,  the  last  rings  of  the  trachea  form 
an  inferior  larynx,  the  bronchi  pass  in  a  mem- 
branous form  through  the  lungs,  and  the  lungs 
open  into  large  membranous  abdominal  air- 
cells,  which  communicate  with  the  interior  of 
the  bones.  This  extensive  aeration  of  their 
systemic  as  well  as  their  pulmonic  vessels  gives 
energy  to  their  muscles  for  their  aerial  life  and 
their  distant  migrations,  and  a  high  tempera- 
ture to  their  body  for  the  incubation  of  the 
egg.  Their  plumage  and  their  downy  covering 
are  the  best  suited  for  their  aerial  life  and  their 
high  internal  heat.  Their  organs  of  generation 
are  double  and  symmetrical  in  the  male,  and 


ANIMAL  KINGDOM. 


117 


generally  unsymmetrical  in  their  development 
in  the  female.  The  testes  are  internal,  and  the 
vasa  deferentia  terminate  in  the  cloaca,  where 
there  is  sometimes  a  grooved  organ  of  intro- 
mission. In  the  female  the  left  ovary  and 
oviduct  are  developed,  the  right  for  the  most 
part  atrophiated  and  useless.  The  cavity  of 
the  cloaca  in  most  birds,  as  seen  in  that  of  the 
great  condor  of  the  Andes  (fig-  49),  receives 
the  end  of  the  rectum  («),  which  forms  a  wide 

Fig.  49. 


rectal  vestibule  (6) :  beneath  this  lies  the  part 
analogous  to  the  urinary  bladder  (c  d).  Lower 
than  the  urinary  sac  are  found  the  two  openings 
of  the  ureters  (//  A),  with  the  pervious  oviduct 
on  the  left  side  (./'),  and  the  remains  of  the 
impervious  oviduct  (g)  on  the  right  side.  The 
bursa  Fabricii  and  the  clitoris  (when  present) 
are  placed  more  posteriorly  in  the  preputial 
cavity.  The  most  distinct  forms  of  these  gene- 
rative and  urinary  parts,  and  the  nearest  ap- 
proach to  the  mammalia  are  seen  in  the  cloaca 
of  the  ostrich  (.//g.  50),  where  the  rectum  (a) 
opens  into  a  wide  and  distinct  rectal  vestibule 
(6),  which  extends  into  a  large  urinary  bladder 
(rf).  Beneath  the  urinary  bladder  is  the  ure- 
thro-sexual  canal  (e),  into  which  the  two  ureters 

Fig.  50. 


(h  k  h*  A*)  and  the  oviducts  (//*/*  #)  °Pen 
towards  the  dorsal  and  lateral  part.  The  pre- 
putial cavity  («')  is  the  terminal  portion  in  which 
the  distinct  clitoris  is  here  lodged.  The  ova 


are  impregnated  internally,  their  chorion  is 
calcined,  and  their  development  is  effected  by 
incubation.  (See  AVES.) 

23.  Mammalia,  warm  and  red-blooded  ver- 
tebrata,  having  four  cavities  of  the  heart,  with 
a  viviparous  mode  of  generation,  and  possessing 
mammary  glands ;  with  the  lungs  free  in  a 
distinct  thoracic  cavity,  and  generally  having 
the  body  more  or  less  covered  with  hair.  The 
bodies  of  their  vertebra  unite  by  flat  surfaces, 
the  tympanic  bone  is  fixed,  the  jaws  are  gene- 
rally furnished  with  teeth  lodged  in  deep  alveoli, 
the  coracoid  bone  rarely  reaches  the  sternum, 
and  the  posterior  extremities,  when  present,  are 
always  attached  by  the  pelvic  arch  to  a  solid 
sacrum.  The  thoracic  and  abdominal  cavities 
are  separated  by  a  muscular  diaphragm.  The 
hemispheres  of  the  brain  contain  large  ventri- 
cles, and  rarely  want  convolutions,  the  optic 
lobes  are  small,  concealed,  solid,  and  divided 
by  a  transverse  sulcus,  the  commissures  of  the 
brain  and  cerebellum,  and  the  hemispheres  of 
the  cerebellum  are  large.  The  alimentary 
canal  is  of  great  length,  the  colon  long  arid 
wide,  with  a  single  crecum,  and  sometimes 
with  a  vermiform  appendix,  and  the  anal  open- 
ing is  generally  distinct  from  the  urinary  and 
genital  passages.  The  tricuspid  valve  is  thin 
and  membranous,  the  aorta  descends  on  the 
left  side,  there  is  no  inferior  larynx,  the  epi- 
glottis is  distinct,  and  the  bronchi  continue 
cartilaginous  into  their  ramifications  in  the 
lungs.  The  lungs,  generally  divided  into  lobes, 
move  freeely  fn  a  distinct  thoracic  cavity,  and 
have  no  abdominal  cells  or  perforations  on  their 
surface,  as  in  birds.  There  is  always  a  urinary 
bladder,  and  the  urethra  in  the  male  passes 
through  a  tubular  penis.  The  organs  of  gene- 
ration are  double  in  both  sexes,  symmetrical  in 
the  male,  and  rarely  unsymmetrical  in  the 
female.  The  oviducts  commonly  unite  at  their 
lower  part  to  form  a  uterus,  in  which  the  ovum 
becomes  again  connected  with  the  parent,  and 
is  hatched.  There  are  mammary  glands  open- 
ing externally  for  lactation  during  the  helpless 
condition  of  the  young.  (See  MAMMALIA.) 

These  are  the  PRIMARY  and  SECONDARY 
DIVISIONS  of  the  ANIMAL  KINGDOM,  the  strtic- 
ture,  classification,  and  history  of  which  it  is 
proposed  to  consider  in  this  Cyclopaedia,  under 
the  heads  of  the  several  classes  as  enumerated  in 
the  subjoined  table. 

ANIMALIA. 

I.  Sub-regnum,  Cyclo-neura  vel  Radiata. 

Classis  1.  Polygastrica. 

2.  Porifera. 

3.  Polypi fera. 

4.  Acalephae. 

5.  Echinoderma. 

II.  Sub-regnum,  Diplo-neura  vel  Articulate. 

Classis  6.  Entozoa. 

7.  Rotifera. 

8.  Cirrhopoda. 

9.  Annelida. 

10.  Myriapoda. 

11.  Insecta. 

12.  Arachnida. 

13.  Crustacea. 


118 


ANIMAL. 


III.  Sub-regnum  Cyclo-gangliatavel  Mollusca. 

Classis  14.  Tunicata. 

15.  Conchifera. 

16.  Gasteropoda. 

17.  Pteropoda. 

18.  Cephalopoda. 

IV.  Sub-regnum  Spini-cerebratavelVertebrata. 

Classis  19.  Pisces. 

20.  Amphibia. 

21.  Reptilia. 

22.  Aves. 

23.  Mammalia. 

For  the  BIBLIOGRAPHY  of  this  article  see  that 
appended  to  each  of  the  articles  on  the  classes  of 
animals  and  COMPARATIVE  ANATOMY  (Introduc- 
tion. ) 

( R.  E.  Grant.) 

ANIMAL  (from  anima,  breath,  the  living 
principle.  Lat.  animal.  Gr.  Qov.  Fr.  animal. 
Germ.  Thier.  Ital  animale).  The  objects  of 
the  material  universe  were  long  considered  as 
arranging  themselves  naturally  into  three  grand 
divisions,  or  kingdoms,  as  they  were  called :  the 
animal,  the  vegetable,  and  the  mineral.  Closer 
attention,  however,  and  a  more  careful  study  of 
the  qualities  and  actions  of  the  various  bodies 
composing  these  kingdoms,  lead  to  the  con- 
clusion that  two  of  them  have  much  in  com- 
mon, and  consequently  that  a  two-fold  division 
suffices  to  comprehend  the  whole  of  the  objects 
in  nature, — these  are  the  inorganic,  or  lifeless, 
and  the  organic,  or  living ;  the  first  embracing 
minerals,  fluids,  gases,  or  the  various  forms 
in  which  simple  brute  matter  presents  itself  to 
our  observation  ;  the  second  including  vegeta- 
bles and  animals. 

As  the  subject  ANIMAL  may  be  regarded  in 
the  light  of  the  very  kernel  and  epitome  of  the 
entire  matter  treated  in  the  pages  of  our 
Cyclopaedia,  we  shall  give  such  extension  to 
this  head  as  its  importance  seems  to  demand, 
studying  brevity  nevertheless,  and  embracing 
in  general  views  the  particular  points  which 
will  be  illustrated  in  detail  in  the  different 
articles  on  anatomy  and  physiology,  human 
and  comparative. 

COMPARISON  OF  THE  ORGANIC  AND  INORGANIC 
WORLDS. 

Physical  qualities  and  elementary  composi- 
tion of  unorganized  and  organized  bodies. — 
The  organic  and  inorganic  kingdoms  of  nature 
are  distinguished  from  one  another  by  many 
strong  features  of  difference, — first,  in  reference 
to  their  general  physical  qualities,  external 
form,  volume,  and  elementary  composition ; 
and  second,  in  regard  to  their  capacities  of 
action. 

The  forms  of  the  objects  composing  the 
inorganic  world,  indeterminate  when  they  are 
considered  in  their  masses,  are  reducible  to  a 
very  few  simple  crystalline  shapes  when  they 
are  regarded  in  their  parts.  The  cube,  the  hexa- 
hedron, the  rhomb,  the  prism,  &c.  are  the  ele- 
mentary forms  of  the  inorganic  world :  plane 
surfaces  and  straight  lines  uniting  under  differ- 
ent inclinations,  and  originating  angles  that 
measure  certain  determinate  numbers  of  de- 


grees are  the  accidents,  which  give  them  their 
characteristic  and  individual  shapes. 

But  the  inorganic  world  has  not  absolutely 
even  this  limited  perfection  of  form,  if  the  ex- 
pression may  be  allowed.  In  order  that  the  ob- 
jects which  compose  it  may  exhibit  themselves 
under  the  form  of  crystals,  solution  of  some 
kind,  rest,  time,  and  space  are  required ;  and 
these  or  any  of  these  being  denied,  the  ob- 
jects of  the*  unorganized  world  present  them- 
selves or  exist  as  simple  aggregates  of  mo- 
lecules, shapeless  in  their  component  parts  as 
in  their  masses.  And  further,  even  when  the 
objects  of  the  inorganic  world  do  present  them- 
selves under  definite  forms,  these  are  not  ne- 
cessary and  invariable.  Carbonate  of  lime, 
to  take  a  single  instance,  occurs  crystallized 
not  only  in  rhombs,  but  in  hexahedral  prisms, 
in  dodecahedrons,  the  several  faces  of  which 
are  pentagons,  in  solids  terminated  by  twelve 
triangles  with  unequal  sides,  &c.  In  their 
material  composition,  too,  unorganized  bodies 
are  essentially  homogeneous:  one  part  of  a 
mineral  does  not  differ  from  another. 

This  is  very  different  from  what  occurs  in 
the  world  of  organization.  From  the  lowest 
to  the  highest  of  living  beings  the  shape  is 
determinate  for  the  individual,  not  only  as 
a  whole,  but  even  as  each  of  its  component 
parts  is  concerned.  Instead  of  being  cir- 
cumscribed within  angles  and  right  lines  like 
the  objects  of  the  inorganic  kingdom,  those 
of  the  organic  are  mostly  rounded  in  their 
forms,  or  they  are  branched,  or  articulated  and 
made  up  of  several  parts,  which  present  varieties 
of  conformation  in  harmony  with  the  kinds  of 
offices  they  have  to  perform,  or  the  conditions 
surrounded  by  which  the  beings  thus  fashioned 
exist.  Neither  do  they  consist  of  homogeneous 
particles  like  minerals,  but  are  made  up  in 
general  of  heterogeneous  parts :  in  plants  we 
have  roots,  leaves,  branches,  flowers,  &c. ;  in 
animals  muscles,  nerves,  bones,  and  a  great 
number  of  organs  besides,  each  itself  reducible 
to  a  variety  of  simpler  parts  or  elements,  en- 
titled tissues. 

The  organic  world  also  presents  an  immea- 
surably greater  variety  of  forms  than  the  in- 
organic :  the  myriads  of  animals  and  vegeta- 
bles that  people  and  possess  the  earth  differ  to 
infinity  from  each  other  in  their  forms  and 
physiognomies. 

Size. — Neither  is  there  less  discrepancy  be- 
tween the  inorganic  and  the  organic  world  in 
the  quality  of  size,  which,  in  the  first,  is 
perfectly  indeterminate,  being  greater  or  less, 
simply  as  the  constituent  molecules  happen 
to  be  aggregated  in  larger  or  in  smaller  num- 
bers. The  volume  of  organized  bodies,  on 
the  contrary,  is  determinate;  every  animal, 
every  vegetable,  has  a  particular  stature,  a  cer- 
tain bulk,  which  is  that  of  its  species  also,  and 
is  within  narrow  limits  alike  in  regard  to  all 
the  individuals  composing  the  kind. 

Composition. — Contrasted  in  their  chemical 
nature,  organized  and  unorganized  bodies  pre- 
sent numerous  and  striking  points  of  dis- 
similarity. Modern  chemistry  enumerates  no 
fewer  than  fifty-two  elementary  or  simple  sub- 


ANIMAL. 


119 


stances,*  besides  the  imponderables  —  light, 
caloric,  and  electricity.  The  whole  of  these 
are  met  with  in  the  mineral  or  inorganic  world; 
but  no  more  than  nineteen  of  them  have  been 
detected  in  the  constitution  of  organized  bo- 
dies.f  Six  of  this  number,  indeed, — oxygen, 
hydrogen,  carbon,  azote,  phosphorus,  and  cal- 
cium, occur  in  such  abundance  as  to  compose 
almost  the  whole  mass  of  organized  bodies ; 
the  remaining  thirteen  are  met  with  but  spa- 
ringly distributed,  and  some  of  them  even 
appear  to  be  adventitious,  and  by  no  means 
essential  to  the  constitution  of  the  bodies  in 
which  they  are  encountered. 

Speaking  generally,  the  chemical  composi- 
tion of  inorganic  objects  may  be  stated  to  be 
the  more  simple,  many  of  them  consisting  of 
a  single  element  only,  and  when  more  com- 
pound generally  presenting  binary,  and  at 
most  ternary  combinations  of  known  elements. 
Organized  bodies,  on  the  other  hand,  are  never 
made  up  of  single  elements,  they  are  not  even 
binary  combinations,  vegetables  in  the  aggre- 
gate being  at  least  ternary,  and  animals  at 
least  quaternary  compounds.  Though  the 
elements  which  compose  inanimate  objects, 
therefore,  are  more  numerous,  the  combinations 
they  enter  into  are  less  complex  than  those  they 
form  in  the  constitution  of  living  things. 

Another  difference  in  the  chemical  consti- 
tution of  unorganized  and  of  organized  bodies 
consists  in  the  mode  or  form  in  which  the  che- 
mical elements  exist  in  each.  In  the  former 
they  present  themselves  immediately  as  it  were, 
the  chemist  in  his  analyses  coming  upon  them 
at  once ;  in  the  latter  they  occur  under  two 
forms,  the  one  immediate  as  in  minerals,  the 
other  mediate,  or  arranged  under  a  variety  of 
new  and  peculiar  shapes,  which,  with  reference 
to  the  bodies  they  mainly  constitute,  are  con- 
veniently and  fairly  spoken  of  as  elements, 
with  the  prefix  organic,  they  being  exclusively 
the  products  of  life  and  organization ;  these 
are  also  frequently  spoken  of  as  the  immediate 
principles  of  vegetables  and  animals. 
.  In  the  inorganic  world,  again,  the  con- 
stituent elements  of  bodies  are  always  united 
by  virtue  of,  and  in  harmony  with,  the  general 
laws  of  chemical  affinity,  whilst  in  the  organic 
the  compounds  formed  are  very  often  even 
the  opposites  of  those  that  would  have  been 
originated  under  the  dominion  of  these  laws. 
From  this  it  comes  that,  whilst  the  chemist 
finds  almost  as  little  difficulty  in  recomposing 

*  Oxygen,  hydrogen,  carbon,  phosphorus,  sul- 
phur, borium,  silenium,  iodine,  fluor,  chlorine, 
bromine,  azote,  silicium,  zirconium,  aluminium, 
yttrium,  glucynium,  magnesium,  calcium,  stron- 
tium, baryum,  potassium,  sodium,  lithium,  man- 
ganese, zinc,  iron,  tin,  arsenic,  molybdenum,  tung- 
sten, columbium,  chromium,  antimony,  ciranium, 
cerium,  cobalt,  titanium,  bismuth,  cadmium,  cop- 
per, tellurium,  lead,  mercury,  nickel,  osmium, 
silver,  gold,  platinum,  palladium,  rhodium,  and 
iridium. 

t  Oxygen,  hydrogen,  carbon,  azote,  phosphorus, 
sulphur,  iodine,  bromine,  chlorine,  floor,  silicium, 
aluminium,  magnesium,  potassium,  sodium,  cal- 
cium, manganese,  iron,  and  copper. 


as  in  disintegrating  inorganic  objects,  he  has 
hitherto  failed  in  compounding  any  one  of  the 
higher  organic  products  or  immediate  prin- 
ciples of  plants  and  animals.*  Chemical 
analysis  we  may  therefore  imagine  to  be  a 
process  of  a  very  different  nature  as  applied 
to  inorganic  objects  from  what  it  is  when  ap- 
plied to  organic  substances.  With  reference 
to  the  former  it  signifies  a  simple  disintegra- 
tion, vvitli  an  inherent  capacity  in  the  elements 
separated  to  reunite  into  the  compound  ana- 
lysed ;  in  the  latter  it  constantly  implies  de- 
struction, without  any  such  continuing  power 
of  recombination  among  the  constituent  ele- 
ments. Chemical  synthesis,  consequently,  is 
an  expression  that  can  only  be  logically  used 
in  connection  with  inorganic  objects. 

Considered  with  reference  to  their  intimate 
texture,  organized  beings  are  no  less  strikingly 
different  from   unorganized  bodies.     The  last 
are  either  solid,  or  fluid,  or  gaseous  ;  they  never 
occur  commingled,    each   subserving  the  ex- 
istence of  the  other.     The  water  of  crystalli- 
zation, and  the  globules  of  this  and  other  fluids 
occasionally  found   included  within  the  sub- 
stance of  minerals,  are  but  adventitious,  being 
in   the   first  instance   entangled   among  their 
component  molecules,  in  the  second  imprisoned 
within  accidental  cavities  in  their  substances 
but  contributing    in   nowise  to  the  existence 
or  duration  of  the  matter  that  surrounds  them. 
Organized  bodies,  on  the  other  hand,  consist 
uniformly  of  solid  and  of  fluid  parts :  whilst 
the  vegetable  has  its  woody  fibre  and  constituent 
parenchyma,  it  has  its  sap  also ;  and  animals 
with  their  firmer  bones,  muscles,  cellular  sub- 
stance,  &c.   have    likewise  blood   circulating 
through   their   bodies,   or   various   fluids   de- 
posited within  their  tissues,  which  are  just  as 
essential  to  their  constitution  and  continuance 
as  the  containing  parts  themselves.     It  is  even 
by  the  mutual  play  of  the  solids  and  fluids 
which  enter  into  the  composition  of  organized 
beings  that  they  manifest  themselves  in  action 
or  exhibit  the  phenomena  which  are  peculiar 
to  them,  and  which  we  denominate  vital.     It 
were   indifferent  whether  we   took   away  the 
solids  (were   such   a   thing   possible)  or  the 
fluids  of  a  vegetable  or  an  animal ;  in  either 
case  it  must  perish.     The  solids  and  fluids  of 
organized  beings  consequently  are  in  intimate 
and  inseparable  relationship  one  with  another. 
Consistence. — From  this  admixture  of  solids 
and  fluids  in  the  world  of  organization  results 
the  variety  of  consistence  which  its  objects  pre- 
sent.    In  the  inorganic  kingdom,  rigidity, — 
rigidity,  too,  which  is  uniform, — is  one  of  the 
distinguishing  characteristics.     In  the  organic, 
on  the  contrary,  pliancy  and  softness,  which 
vary  as  well  in  every  individual  as  in  almost 

*  The  exceptions  to  this  position  are  scarcely 
worth  noticing— one  or  two  of  the  more  simple 
organic  elements,  oxalic  acid  and  urea,  for  ex- 
ample, have  been  formed  synthetically,  and  a 
substance  bearing  a  remote  affinity  to  fat  has  also 
been  produced.  No  one,  however,  has  ever  suc- 
ceeded in  forming  fibrinc,  neurine,  fecula,  gum, 
&c.  synthetically. 


120 


ANIMAL. 


every  part  of  the  same  individual,  are  no  less 
strongly  marked  and  inherent  features.  So- 
lidity or  hardness  may  be  looked  upon  as  the 
term  of  perfection  of  a  mineral ;  softness,  on 
the  other  hand,  often  appears  to  be  the  term  of 
perfection  among  vegetables  and  animals,  the 
parts  in  these  being  generally  softer  in  proportion 
as  they  have  more  important  or  noble  offices  to 
perform.  The  tender  fibrils  of  the  root,  the 
leaves,  flowers,  stamina  and  pistilla  in  plants ; 
the  brain,  vessels,  viscera,  &c.  in  animals,  are 
softer  than  the  bark  and  woody  fibre,  than  the 
bones,  ligaments,  skin,  &c.  which  form,  as 
it  were,  but  the  frame  and  covering  of  the 
proper  fabric.  This  quality  also  varies  in  the 
organic  world  according  to  the  age  of  the  in- 
dividual :  the  nearer  any  organized  being  is  to 
its  birth  or  origin,  the  softer  will  it  generally  be 
found  to  be ;  the  longer  it  has  lived,  the  harder 
will  it  as  uniformly  be  ascertained  to  have 
become.  Many  organized  beings,  indeed,  in 
the  first  stages  of  their  existence,  are  wholly 
fluid;  they  only  acquire  consistence  as  they 
are  evolved  and  approach  maturity. 

It  is  almost  needless  to  speak  of  the  ex- 
tent to  which  inorganic  bodies  differ  from  or- 
ganic in  these  respects;  they  are  rigid  and 
hard  in  all  their  parts  alike,  and  never  vary  in 
consistence  from  the  moment  of  their  forma- 
tion to  that  of  their  disintegration  or  decom- 
position. 

The  elementary  particles  or  molecules  en- 
tering into  the  composition  of  organized  and 
unorganized  objects,  also  differ  in  their  essen- 
tial nature.  All  organized  beings,  in  fact, 
whether  their  solids  or  fluids  are  regarded, 
appear  to  be  made  up  of  or  to  contain  glo- 
bular or  oval  and  sometimes  flattened  cor- 
puscles. The  simplest  plants, — the  confervae, 
tremellae,  &c.,  and  the  simplest  animals, — the 
infusoria,  polypi,  &c.,  are  alike  composed  of 
globules  and  a  fluid ;  nor  is  the  case  different 
as  regards  the  most  complicated  vegetable  or 
animal  that  exists.  The  elementary  globule 
has  now  been  discovered  in  almost  all  the 
solids  and  fluids  both  of  vegetable  and  of 
animal  bodies, — in  the  sap  and  cambium  or 
succus  proprius  of  vegetables,  and  in  the 
blood,  chyle,  milk,  and  other  fluids  of  animals ; 
in  the  fecula,  albumen,  parenchyma  of  the 
leaves,  cells  of  the  flowers,  &c.  of  plants,  and 
in  the  cellular  membrane,  muscle,  brain,  nerve, 
gland,  &c.  of  animals. 

Nothing  of  the  same  kind  has  yet  been  de- 
tected among  inorganic  bodies.  Angular  par- 
ticles separable  to  infinity  into  others  of  a  like 
description  are  the  elements  of  composition  in 
minerals. 

Globules,  then,  are  to  be  regarded  as  the 
elementary  constituents  of  organized  bodies, 
as  the  ultimate  molecules  possessing  a  distinct 
form,  which  by  their  aggregation  compose  them. 
The  first  step,  indeed,  in  the  singular  pro- 
cess by  which  infusory  animals  are  eliminated 
during  the  decomposition  of  organized  sub- 
stances, is  the  formation  of  globular  corpuscles; 
these,  by  their  subsequent  aggregation  in  some 
cases  and  individual  evolution  in  others, 


appear  to  give  birth  to  the  organized  atoms 
that  by-and-by  make  their  appearance ;  and, 
as  we  have  said,  globules  are  now  admitted  to 
form  the  basis  of  the  different  tissues  which 
enter  into  the  composition  of  the  very  highest 
among  animals.  These  various  tissues,  in  fact, 
would  seem  to  result  from  the  different  modes 
in  which  the  elementary  globules  are  disposed  ; 
and  it  is  not  improbable  that  the  difference 
of  function  they  exhibit  may  yet  be  found  in 
harmony  with,  and  perhaps  depending  on,  pe- 
culiarity of  arrangement  in  their  constituent 
molecules. 

This  aggregation  of  the  organic  molecules 
into  a  variety  of  tissues  and  peculiar  organs 
forms  another  essential  feature  of  difference 
between  the  organized  and  the  unorganized 
world.  Minerals,  indeed,  as  they  manifest  no 
variety  of  phenomena  analogous  to  those  of 
life,  required  no  diversity  of  elementary  con- 
stitution in  their  different  parts  ;  they  are  con- 
sequently homogeneous.  In  minerals  the  com- 
ponent molecules  are  arranged  in  layers  placed 
one  upon  another,  so  that  their  crystals  can  be 
readily  cleft  in  a  variety  of  directions,  according 
to  the  elementary  arrangement  of  these.  In 
vegetables  and  animals,  on  the  other  hand,  the 
constituent  molecules  always  form  tissues,  the 
fibres  of  which  interlace  or  cross  one  another  ; 
in  no  living  or  organic  thing  do  we  observe 
aught  similar  to  what  is  called  the  cleavage  in 
minerals. 

From  this  it  comes  that  minerals  are  as  com- 
plete in  their  parts  as  they  are  in  their  masses  : 
the  minutest  spark  of  carbonate  of  lime  has  all 
the  properties  of  a  crystal  of  this  substance, 
were  it  as  large  as  a  mountain.  The  case  is 
very  different  in  regard  to  organized  beings  ; 
these  consist  of  a  number  of  organs,  the  sum 
of  whose  actions  constitutes  the  peculiar  vitality 
of  each  being,  and  no  individual  part  or  organ 
enjoys  capacity  to  manifest  itself  abstractedly 
from  the  system  to  which  it  belongs.  All  the 
parts  of  organized  bodies  are  mutually  en- 
chained by  bonds  of  the  strictest  causality; 
this  even  follows  necessarily  from  the  manner 
in  which  they  originate  and  are  evolved.  The 
radicle  that  bursts  from  the  fecundated  seed 
of  a  plant  determines  the  growth  of  the  stem, 
which  subsequently  and  in  its  turn  plays  the 
same  part  with  reference  to  the  leaves  and 
flowers, — the  parts  that  appear  first  are  the 
cause  of  the  appearance  of  those  that  follow 
at  later  stages.  No  relation  of  this  kind  exists 
among  inorganic  bodies.  When  a  crystal  is 
formed  in  the  midst  of  a  fluid,  the  particles 
composing  it  unite,  in  conformity  with  the  mere 
laws  of  cohesion  and  affinity,  not  in  consequence 
of  any  determining  influence  in  the  particles 
which  cohered  the  first,— each  stage  or  period 
of  the  process  of  crystallization  is  independent 
of  that  which  preceded  it.  Whilst  the  parts 
of  an  inorganic  body,  therefore,  can  exist  with 
all  their  qualities,  as  well  in  a  state  of  disin- 
tegration as  in  one  of  aggregation,  the  com- 
ponent parts  of  organic  bodies  can  only  exist 
with  their  distinguishing  properties  when  united 
to  the  entire  being.  Individuality  in  the  or- 


ANIMAL. 


121 


ganic  world,  far  from  existing  in  the  integral 
molecule  as  it  does  in  the  inorganic,  can  only 
be  said  to  exist  in  the  mass  of  integral  mo- 
lecules united  into  that  congeries  of  organs 
which  constitutes  a  particular  being.  As  a 
consequence  of  this  independence  on  the 
one  hand,  and  dependence  on  the  other,  we 
find,  that  whilst  in  the  inorganic  world  the 
several  parts  may  be  modified  without  the 
others  feeling  the  influence  of  the  change  in- 
duced, in  the  organic,  implication  of  one  part 
and  modification  of  one  action  are  commu- 
nicated to  and  manifested  in  the  state  and 
actions  of  all  the  other  parts. 

Considered  with  regard  to  their  duration, 
the  objects  composing  the  organic  and  the 
inorganic  world  differ  essentially.  In  the  former 
this  period  is  determinate  and  definite,  and, 
although  it  varies  greatly,  it  depends  in  a  great 
measure  on  circumstances  inherent  in  the  in- 
dividuals ;  in  the  latter  it  is  indeterminate  and 
indefinite,  and  when  the  objects  composing  it 
cease  to  be,  it  is  generally  in  consequence  of 
circumstances  exterior  to  themselves.  Organized 
beings  exist  for  a  limited  time  and  in  oppo- 
sition to  many  of  the  physico-chemical  laws ; 
unorganized  beings  exist  indefinitely,  and  only 
in  harmony  with  the  whole  of  these  laws. 
Organic  beings  continue  to  exist  in  conse- 
quence of  a  kind  of  reciprocal  action  with 
external  things,  and  especially  by  virtue  of  an 
incessant  change  and  renewal  in  their  con- 
stituent elements.  The  very  condition  of  ex- 
istence of  an  unorganized  body  is  quiescence ; 
any  new  action  between  its  molecules  them- 
selves, or  between  these  and  others  external  to 
them,  any  addition  to,  or  subtraction  from,  its 
component  parts,  implies  the  destruction  of  its 
individuality. 

In  the  organic  world,  new  forms  result  from 
the  actions  of  forms  already  existing,  which 
have  the  wonderful  property  of  producing 
others  similar  to  themselves  ;  and  this  in  virtue 
of  no  general  physico-chemical  law,  but  of 
an  especial  power  inhering  in  each  organized 
being  individually.  There  is  nothing  like  this 
faculty  of  procreation  or  of  generation  in  the  in- 
organic world.  When  a  crystal  is  produced,  it 
is  necessarily  at  the  expense  of  one  or  of  others 
that  have  already  existed,  or  of  a  combination 
of  the  elements  of  these ;  destruction  is  here  a 
necessary  preliminary  to  production,  and  the 
process  is  simply  one  of  re-formation,  not  of 
genesis  or  creation.  Neither  in  the  re-forma- 
tions of  the  inorganic  world  do  we  find  that  the 
forms  are  always  necessarily  the  same  as  those 
which  preceded  them :  the  crystalline  form 
doe.s  not  depend  on  the  nature  of  the  integral 
molecules,  but  on  their  mode  of  aggregation 
and  number.  In  the  organized  world,  again, 
nothing  is  more  certain  and  fixed  than  that  the 
form  of  the  new  being  shall  resemble  that 
which  gave  it  birth. 

The  last  distinction  we  shall  mention  under 
this  head  of  material  composition  and  physical 
qualities  between  organic  and  inorganic  bodies 
is,  perhaps,  less  striking,  though  not  less  in- 
teresting on  that  account :  it  is  this, — that  whilst 


in  inorganic  bodies  the  composition  is  quite  de- 
terminate, in  organised  beings,  although  con- 
stituting particular  species,  the  composition 
may  present  individual  differences  or  modifica- 
tions. These  are  designated  by  the  titles  tem- 
perament, constitution,  4  c-  There  is  no  corres- 
ponding modification  recognizable  in  the  in- 
organic world. 

From  what  has  now  been  said,  it  appears 
that  organized  and  unorganized  bodies  differ 
essentially  from  one  another  in  their  general 
physical  qualities  and  material  constitution. 
The  form  of  the  organized  being  is  determinate, 
and  its  outline  is  rounded  or  undulating;  its 
size  is  limited ;  its  duration  is  temporary  ;  its 
composition  is  an  assemblage  of  heterogeneous 
parts,  of  solids  and  fluids,  arranged  so  as  to 
compose  a  variety  of  fibrous  and  cellular 
tissues,  and  aggregates  of  organs  or  parts 
differing  from  one  another  in  their  form,  struc- 
ture, and  functions,  but  all  nevertheless  mu- 
tually dependent  one  upon  the  other,  and  con- 
curring to  a  common  end, — the  preservation 
of  the  individual,  which  has  place  by  virtue  of 
an  internal  activity  denominated  life,  amulst 
incessant  changes  and  renovations  of  the 
matter  entering  into  its  composition,  and 
the  continuation  of  the  species,  which  is  a 
genesis  or  creation,  implying  neither  destruc- 
tion nor  alteration  in  the  mode  of  being  of 
the  individual  or  individuals  from  whom  the 
new  formation  springs. 

Actions  of  unorganized  and  of  organized 
objects.  —  But  form,  size,  material  composi- 
tion, duration,  mode  of  origin,  &c.  are  not 
the  only  particulars  in  the  history  of  or- 
ganic and  inorganic  bodies  which  are  capa- 
ble of  being  contrasted,  and  in  which  differences 
may  be  made  to  appear. 

All  that  exists  is  active;  every  entity  performs 
actions,  or  manifests  forces  by  which  its  own  ex- 
istence is  continued,  and  by  which  it  participates 
in  the  various  phenomena  of  the  universe.  Of 
these  actions  or  forces  there  are  two  grand 
classes,  the  one  general,  the  other  special :  the 
first  are  the  physico-chemical  laws  which  per- 
vade space  and  include  the  universe ;  the 
second  are  the  vital  laws,  which  embrace  within 
their  dominion  plants  and  animals,  or  things 
organized  and  having  life. 

The  most  general  of  all  the  forces  possessed 
are  those  of  attraction  and  repulsion,  which 
inhere  in,  and  are  manifested  by,  all  existing 
things,  organic  as  well  as  inorganic.  Every 
object  gravitates  or  has  weight,  coheres  in  its 
several  parts,  exhibits  chemical  affinities,  and 
yields  to  the  expansive  influence  of  caloric. 
Inorganic  objects  exhibit  these  general  forces 
alone,  and  are  absolutely  under  their  control. 
Organized  bodies  are  also  subjected  to  the  same 
general  forces;  but  they  are  often  modified, 
nay,  they  are  sometimes  even  abrogated  and 
set  at  nought  by  vegetables  and  animals  alike, 
in  virtue  of  the  special  powers  inherent  in 
themselves.  These  special  powers  have,  in  fact, 
the  singular  property  of  subtracting,  in  various 
degrees,  the  beings  they  actuate  from  the  in- 
fluence of  the  general  laws  of  creation.  In- 


122 


ANIMAL. 


stead  of  obeying  the  universal  law  of  gravita- 
tion, vegetables,  for  instance,  shoot  upwards, 
and  propel  their  juices  from  the  roots  to  the 
leaves ;  animals  also  distribute  their  blood  in 
opposition  to  the  laws  of  gravitation,  and  by 
their  powers  of  motion  overcome  the  universal 
physical  law  that  tends  to  fix  them  in  one  place. 
The  force  of  cohesion  is  not  a  merely  passive 
property  in  the  organized  as  it  is  in  the  unorgan- 
ized world,  and  the  laws  of  chemical  affinity 
are  especially  set  at  nought  both  by  plants  and 
animai?,  their  constituent  elements  being  even 
generally  united  into  combinations  the  con- 
trary of  those  which  these  laws  ordain.  Animals 
and  vegetables  are  farther  abstracted  from  the 
general  law  of  caloric,  the  more  perfect  of  them 
at  least  having  a  specific  temperature,  inde- 
pendent of  that  of  the  medium  which  sur- 
rounds them,  and  which  varies  in  conformity 
with  changes  in  the  peculiar  actions  of  which 
in  them  it  is  the  product. 

There  is  even  a  distinction  between  the 
organized  and  unorganized  world  to  this  extent, 
— that  while  the  physico-chemical  laws  do- 
minate the  inorganic  world  rigorously,  and  the 
bodies  that  belong  to  it  seem  to  have  begun 
to  be  as  they  continue  to  exist  through,  or  in 
harmony  with,  their  prescriptions,  no  organized 
body  known  has  either  sprung  into  being  or 
continues  to  exist  through  the  agency  of  purely 
physical  or  purely  chemical  forces.  The  whole 
of  the  special  properties  of  organized  beings 
consequently  must  be  held  to  be  effects  of  the 
agent  denominated  life,  and  of  the  laws  which 
this  agent  originates.  The  organized  world  is, 
therefore,  a  creation  within  a  creation,  a  some- 
thing superadded  to  the  material  universe  and 
to  the  generally  pervading  forces  that  keep  its 
parts  in  their  places,  and  endow  them  with 
what  may  be  called  their  necessary  pro- 
perties. 

Nor  is  it  only  whilst  endowed  with  life  that 
organized  differ  from  unorganized  beings. 
Many  of  the  distinguishing  and  peculiar  pro- 
perties of  these  remain  for  a  season  at  least 
after  life  has  left  the  organization  it  had  built 
up.  The  extensibility  and  elasticity  of  the 
tissues  of  animals  especially,  were  held  by 
the  distinguished  Bichat  as  even  independent 
of  life,  which  he  owned  increased  their  energy, 
but  which  he  denied  as  their  cause,  seeing  that 
they  continue  to  exist  after  death.  These  pro- 
perties are  undoubtedly  peculiar,  and  are  at 
all  events  effects  of  forces  which  life  has  called 
into  play,  both  the  tissues  which  possess 
elasticity  and  contractility,  and  these  qualities 
themselves  having  been  engendered  under  the 
influence  of  vitality. 

In  these  properties,  forces  or  capacities  of 
action  common  to  all  the  objects  of  nature, 
unorganized  as  well  as  organized,  we  see  the 
objection  to  the  old  denomination  of  inert, 
which  was  applied  to  one  of  the  great  classes. 
Nothing  that  exists  is  inert  or  inactive ;  but 
organized  have  an  infinitely  wider  field  of 
action  than  unorganized  bodies.  Let  us,  in 
illustration  of  this  position,  examine  in  succes- 
sion the  various  actions  by  which  bodies  gene- 


rally originate,  continue  their  existence,  un- 
dergo such  modifications  as  they  present  in  the 
course  of  their  existence,  and  by  which  they 
come  to  an  end  or  die. 

Origin. — Unorganized  bodies,  minerals  for 
example,  commence  their  existence  from  the 
instant  that  circumstances  exterior  to  them- 
selves detach  them  from  the  mass  of  some 
other  mineral,  precipitate  them  from  a  state  of 
solution  in  a  fluid,  or  brin«  their  constituent 
elements  into  a  position  in  which  they  can 
combine  together.  In  this,  it  is  evident,  there 
is  nothing  like  generation,  as  the  term  is 
applied  to  organized  bodies,  which  all  alike, 
vegetables  as  well  as  animals,  spring  from  a 
molecule,  an  atom,  which  has  once  belonged 
to,  and  which  has  proceeded  from,  a  being 
similar  to  themselves.  Vegetables  spring  from 
seeds,  animals  from  eggs.  Organized  beings, 
therefore,  are  engendered,  their  existence 
is  a  consequence  of  that  of  other  beings  like 
themselves  ;  and  in  their  succession  they 
depend  one  upon  another.  Minerals,  on  the 
contrary,  have  no  powers  of  reproduction  ; 
they  cease  to  be,  if  at  any  time  they  originate 
another  mineral,  and  they  are  individually  in  a 
state  of  perfect  independence.* 

In  the  mode  in  which  organic  and  inorganic 
bodies  continue  their  existence,  there  is  also  a 
striking  dissimilarity.  In  the  inorganic  world 
we  observe  no  actions  tending  to  preserve  the 
individual,  other  than  those  which  have  pre- 
sided over  its  formation  :  it  continues  to  exist 
through  the  continuing  agency  of  the  affinities 
and  of  the  attraction  of  cohesion  which  called 
it  into  being.  Animals  and  vegetables,  on  the 
contrary,  have  special  powers  for  their  pre- 
servation superadded  to  those  by  the  peculiar 

*  It  were  long  to  enter  here  into  the  discussion 
of  what  has  been  called  equivocal  generation,  which, 
if  admitted,  militates  against  several  of  the  in- 
ferences just  deduced.  It  is  quite  certain  that 
infusions  of  any  organized  substance  do  speedily 
become  filled  with  animals  distinct  in  their  kinds 
and  lately  shown  to  be  much  more  complicated  in 
their  structure  than  was  long  supposed.  It  is 
almost  as  difficult  to  conceive  that  these  infusory 
animals  proceed  from  eggs  contained  in  the  fluids 
in  which  they  appear,  as  to  imagine  that  they 
proceed  from  the  combination,  per  se,  of  their  con- 
stituent elements.  Did  we  incline  to  admit  the 
reality  of  equivocal  generation,  it  is  certain  that 
its  occurrence  must  be  referred  to  other  than  the 
general  laws  of  nature,  with  which  we  have  al- 
ready had  occasion  to  show  the  laws  of  life  to  be 
in  opposition,  much  rather  than  in  harmony.  It 
would  be  absurd  to  believe  that  these  general 
physico-chemical  laws,  absolutely  inimical  to  life, 
should  at  any  time  call  it  into  being.  Equivocal 
generation  being  acknowledged,  therefore,  it  would 
seem  necessary  to  infer  a  third  order  of  laws  be- 
sides the  physico-chemical  and  the  vital,  the 
nature  of  which  is  altogether  unknown  to  us. 
The  number  of  creatures  which  were  presumed 
to  owe  their  being  to  equivocal  generation,  has 
been  very  much  curtailed  by  the  progress  of  science 
in  modern  times  ;  and  it  is  not  impossible  that  the 
mystery  which  still  overhangs  the  genesis  of  the 
infusoria  may  one  day  be  dissipated,  and  their  pro- 
duction demonstrated  to  be  in  harmony  with  those 
laws  which  are  known  to  preside  over  the  origin 
of  higher  classes  of  vegetables  and  animals. 


ANIMAL. 


123 


agency  of  which  they  have  been  created. 
Inorganic  bodies  exist  through  the  absence  of 
all  change  in  their  interior;  organized  beings 
exist  by  force  of  change :  there  are  two  pro- 
cesses, one  of  renewal,  the  other  of  decom- 
position, perpetually  going  on  within  them  ; 
they  are  continually  appropriating  from  bodies 
exterior  to  themselves  a  quantity  of  matter 
which  they  have  the  singular  faculty  of  ela- 
borating into  their  proper  substance,  and  they 
have  at  the  same  time  the  power  of  withdraw- 
ing portions  of  the  matter  which  already  forms 
them,  and  rejecting  these  from  their  interior  as 
no  longer  fitted  for  their  preservation.  Vege- 
tables, by  means  of  their  roots  and  their  leaves, 
draw  from  the  earth  and  from  the  air  materials 
which  they  elaborate  into  juices  fitted  for  their 
nourishment,  at  the  same  time  that  they  throw 
off,  especially  by  means  of  their  leaves,  a  por- 
tion of  the  matter  which  had  been  absorbed, 
either  as  superfluous  or  as  improper  to  enter  into 
their  composition.  In  the  same  manner  ani- 
mals appropriate  to  themselves  various  amounts 
of  matter  in  the  shape  of  atmospheric  air  and 
food,  from  which  they  prepare  a  fluid  proper 
for  their  maintenance,  at  the  same  time  that 
they,  by  virtue  of  peculiar  processes,  with- 
draw from  their  bodies  such  portions  of  mat- 
ter as  have  already  fulfilled  their  destination, 
and  cast  them  out  under  the  form  of  excre- 
tions. Organized  bodies,  consequently,  are 
preserved  as  individuals  by  a  process  of  nu- 
trition, a  process  which  implies  dependence 
on  other  bodies,  and  alternate  appropriation 
and  rejection  of  the  particles  of  these ;  the  ex- 
istence of  an  organized  being,  in  fact,  only  con- 
curs with  the  presence  and  appropriation  of 
substances  external  to  itself,  with  a  perpetual 
accession  of  matter  on  the  one  hand,  and  of  its 
rejection  on  the  other,  whilst  unorganized 
bodies  are  more  certainly  continued,  as  their 
state  of  isolation  or  abstraction  from  all  ex- 
ternal influences  is  more  complete.  Organized 
beings,  in  a  word,  continue  to  exist  by  virtue 
of  certain  inherent  especial  powers ;  un- 
organized simply  by  virtue  of  the  general 
powers  that  pervade  the  universe  in  harmony 
with  which  they  were  originally  framed. 

The  modifications  undergone  by  organized 
and  unorganized  bodies  are  peculiar  and  cha- 
racteristic in  each  class.  In  the  first  place 
modification  or  change  is  no  necessary  con- 
dition to  the  existence  of  an  unorganized  body, 
as  it  is  of  one  that  is  organized.  A  mineral  in 
a  state  of  complete  isolation  might  remain 
eternally  unchanged  ;  a  plant  or  an  animal,  on 
the  contrary,  cannot  be  conceived  as  existing 
for  a  moment  abstracted  from  the  universe 
around  it,  and  without  undergoing  change. 
A  mineral,  in  the  instant  of  its  formation, 
acquires  all  the  properties  that  distinguish  it  at 
any  after-stage  of  its  existence ;  in  plants  and 
animals,  on  the  other  hand,  as  we  witness  an 
origin,  so  we  observe  a  series  of  modifications 
denominated  ages, — they  commence  their  ex- 
istence, they  increase  in  size,  they  attain  ma- 
turity, and  they  decline  and  ultimately  die. 

Any  change  which  unorganized  bodies  ex- 
hibit is  accidental,  and  happens  under  the 


influence  of  agencies  external  to  themselves ; 
the  changes  which  organized  beings  undergo 
in  the  course  they  run  from  incipience  to  their 
end,  are  on  the  contrary  necessary,  and  take 
place  in  consequence  of  powers  inherent  in 
themselves. 

Any  change  which  an  unorganized  body  ex- 
periences happens  on  its  surface :  its  mass  is 
increased  or  diminished  by  simple  addition  to 
or  subtraction  from  its  particles;  it  does  not 
increase,  neither  does  it  shrink  and  decay  in 
all  its  parts  like  plants  and  animals,  in  which 
increase  and  diminution  take  place  at  one  and 
the  same  time  from  within  and  from  without. 
Increase  in  the  unorganized  world  happens 
through  juxta-position,  in  the  organic  through 
intus-smccption.  Organized  bodies,  conse- 
quently, as  they  alone  are  generated,  as  they 
alone  possess  powers  of  self-preservation  and  of 
reproduction,  so  do  they  alone  grow,  advancing 
necessarily  from  infancy  to  maturity  and  old 
age,  or  exhibit  what  are  called  ages.  (See  AGE.) 
Organized  bodies  further  meet  our  obser- 
vation in  two  different  states, — those,  namely, 
of  health  and  of  disease,  nothing  correspond- 
ing to  which  is  encountered  in  the  inorganic 
world. 

Whatever  has  a  beginning  has  also  an  end. 
But  the  mode  in  which  organized  and  un- 
organized bodies  cease  to  be,  and  the  influences 
that  determine  their  periods  of  being,  are  ex- 
tremely different.  A  mineral  ends  when  the 
affinities  that  combined  it,  and  the  attraction 
of  cohesion  that  held  its  particles  together,  are 
overcome.  This  language  implies  that  its 
destruction  is  effected  by  agencies  external  to 
itself — by  the  action  of  other  bodies,  and  of 
circumstances  over  which  it  has  no  controul. 
The  destruction  of  a  mineral  is,  therefore,  in 
nowise  necessary,  neither  is  it  spontaneous : 
abstract  a  mineral,  as  we  have  said,  from  all 
external  agency,  and  its  endurance  is  inde- 
finite. 

Very  different  is  the  case  with  regard  to 
animals  and  vegetables ;  as  their  continuance 
depends  on  the  process  of  nutrition,  their  end 
hangs  upon  the  cessation  of  this  act;  and  as 
the  tenure  by  which  they  enjoy  existence  is 
temporary,  the  machine  of  organization  being 
calculated  to  endure  but  for  a  season,  their 
death  or  destruction  is  both  spontaneous  and 
necessary.  Organized  bodies  which  alone  owe 
their  being  to  generation,  which  alone  continue 
their  existence,  reproduce  their  kinds,  grow, 
attain  maturity,  and  become  aged  by  virtue  of 
powers  inherent  within  themselves,  so  do  they 
alone  die. 

The  period  of  endurance  of  unorganized 
bodies  may  often  be  calculated  approximatively 
according  to  their  masses,  their  densities,  the 
aptitudes  of  their  elements  to  enter  into  new 
combinations,  &c.;  that  of  organized  bodies 
cannot  be  inferred  from  these  or  any  other 
merely  mechanical  principles.  Indeed,  data 
from  which  the  duration  of  organized  bodies 
may  be  estimated  are  altogether  wanting.  We 
only  know  that  every  species  has  within  nar- 
row limits  a  period  which  it  cannot  pass ;  but 
why  this  period  should,  in  particular  instances, 


124 


ANIMAL. 


be  confined  to  a  few  weeks,  months,  or  years, 
or  be  extended  to  centuries,  we  cannot  tell. 

Nor  is  it  only  whilst  endowed  with  all  their 
peculiar  and  inherent  properties  that  organized 
differ  from  unorganized  bodies.  No  longer 
manifesting  their  especial  powers,  organized 
bodies  begin  to  be  disintegrated ;  their  con- 
stituent elements,  held  together  in  opposition 
to  the  laws  of  chemical  affinity,  become  ame- 
nable to  these,  and  forthwith  enter  into  new 
combinations,  which  imply  the  utter  destruc- 
tion of  the  organization  as  it  had  been  formed, 
and  hitherto  preserved.  Organized  beings,  as 
they  alone  die,  so  do  they  also  alone  undergo 
putrefaction — a  process  nothing  precisely  si- 
milar to  which  occurs  in  the  inorganic  world. 

From  this  review  of  the  distinguishing  pecu- 
liarities of  organized  and  unorganized  bodies, 
it  appears  that  organization  implies  vitality, 
and  that  organization  and  life  are  insepara- 
ble conditions.  It  would  be  going  too  far 
to  say  that  they  were  synonymous  terms : 
organization  is  the  mode  of  structure  proper 
to  living  beings ;  life  is  the  series  of  actions 
they  exhibit.  And  this  in  fact  appears  to  be 
about  the  least  objectionable  definition  of  life 
than  can  be  given  :  life  in  the  series  of  actions 
manifested  by  organized  beings ;  would  we  go 
farther,  we  must  condescend  upon  an  enumera- 
tion of  these  actions, — namely,  incipience  by 
a  genesis  or  creation ;  temporary  endurance  as 
individual  by  nutrition,  and  indefinite  continu- 
ance as  species  by  reproduction,  modification 
during  the  term  of  existence  known  by  the 
title  of  age,  and  end  by  death,  to  which  spe- 
cific acts  or  phenomena  must  be  added  the 
peculiar  inherent  power  which  living  beings 
possess  of  overcoming  the  general  physico- 
chemical  laws  that  dominate  the  rest  of  the 
universe. 

Thus  far  we  have  discussed  and  contrasted 
the  physical  qualities  and  phenomena  common 
to  organized  or  living  beings  at  large,  with 
such  as  inhere  or  are  manifested  by  unorganized 
bodies  generally,  more  especially  minerals;  we 
have  still  left  untouched  those  that  severally 
pertain  to  the  two  grand  divisions  of  the  or- 
ganized world,  and  that  are  peculiar  to  each 
living  thing  individually;  and  here  we  shall 
find  that  the  manifestations  of  vitality  are  al- 
most as  various  as  the  species  that  people  the 
earth.  In  the  same  manner  as  we  have  hitherto 
gone  on  contrasting  first  the  material  compo- 
sition, and  then  the  actions  of  organic  and 
inorganic  bodies,  we  shall  still  proceed  by 
comparing  the  material  composition  and  the 
capacities  of  action  of  the  different  classes  of 
organized  beings  first,  and  next  of  the  several 
individuals  composing  these  classes  one  with 
another. 

COMPARISON  OF  ANIMALS  AND  VEGETABLES. 

Animals  and  vegetables  were  longheld  essenti- 
ally and  irreconcilably  distinct  from  one  another. 
We  have  already  had  occasion,  however,  to 
observe  in  how  many  particulars  they  are  iden- 
tical. The  material  composition  of  both  is  often 
in  opposition  with  the  general  physico-chemical 
laws,  both  are  made  up  of  a  combination  of 


solids  and  fluids,  both  consist  of  a  variety  of 
heterogeneous  parts,  and  both  have  determinate 
sizes  which  they  cannot  exceed.  Moreover, 
both  are  possessed  of  vitality, — in  other  words, 
both  commence  by  a  genesis,  preserve  them- 
selves as  individuals  by  nutrition,  and  as  spe- 
cies by  reproduction  ;  both  grow  by  intus-sus- 
ception,  undergo  the  mutations  which  are 
denominated  ages,  endure  for  a  time,  present 
themselves  in  health  or  labouring  under  disease, 
and  both  decay  and  die.  How  intimately  ani- 
mals and  vegetables  are  associated,  how  nearly 
they  resemble  one  another,  will  farther  appear 
as  we  advance  in  the  following 

Comparison  of  the  general  physical  qualities 
and  material  composition  of  Vegetables  and 
Animals. — As  a  general  axiom  the  material 
constitution  of  vegetables  may  be  said  to  be 
less  complex  than  that  of  animals;  this  at  least 
is  more  especially  the  case  as  the  individuals 
at  the  top  of  the  two  scales  are  concerned. 

No  distinguishing  feature  of  either  class  is 
derivable  from  general  diversity  of  Size.  Be- 
tween the  microscopic  lichen  and  infusory  ani- 
mal, and  the  gigantic  adansonia  and  whale, 
plants  and  animals  of  every  intermediate  mag- 
nitude are  encountered. 

Neither  is  there  much  to  be  said  upon  the 
differences  which  vegetables  and  animals  pre- 
sent when  their  Forms  are  contrasted.  The 
forms  of  many  are  alike  amorphous,  or  simply 
globular ;  certain  pulverulent  fungi  in  the  one 
class,  and  monads  in  the  other,  resemble  each 
other  greatly.  Among  both,  individuals  also 
occur  whose  parts  are  disposed  around  a  centre ; 
yet  we  do  not  advance  far  before  we  discover  a 
peculiarity  in  animals,  namely,  composition  by 
the  union  of  two  similar  or  symmetrical  halves 
along  a  middle  line  or  axis,  nothing  similar  to 
which  has  even  been  imagined  in  the  vegetable 
world,  the  members  of  which  on  the  contrary 
often  exhibit  a  horizontal  division,  but  without 
anything  of  symmetry,  into  root  and  branches. 
As  a  general  law  the  animal  kingdom  may  be 
said  to  affect  the  globular  or  simply  produced 
form,  with  radii  in  the  shape  of  extremities 
sent  off  from  a  central  part ;  the  vegetable  to 
exhibit  a  greater  tendency  to  ramification  or 
division  into  branches. 

In  point  of  chemical  composition  animals 
and  vegetables  consist  very  nearly  of  the 
same  elements:  oxygen,  hydrogen,  carbon, 
nitrogen,  phosphorus,  sulphur,  iodine,  bro- 
mine, chlorine,  potassium,  sodium,  calcium, 
silicium,  magnesium,  manganese,  and  iron 
have  been  detected  in  both;  aluminium  and 
copper  have  hitherto  only  been  discovered  in 
vegetables,  and  fluor  only  in  animals.  But 
these  elements  are  united  in  each  in  very  dif- 
ferent relative  proportions.  Carbon  predomi- 
nates greatly  in  the  more  solid  parts  of  vege- 
tables,  nitrogen  in  the  bodies  of  animals  gene- 
rally, although  to  this  rule  there  are  many  notable 
exceptions ;  albumen,  fibrine,  and  gelatine  all 
contain  much  more  carbon  than  nitrogen,  and 
certain  fungi  include  a  very  large  proportion  of 
nitrogen  in  their  composition.  Several  ele- 
ments, met  with  abundantly  in  animals,  occur 
but  sparingly  distributed  among  vegetables, 


ANIMAL. 


125 


phosphorus,  for  example,  and  sulphur.  The 
earth  afforded  by  animal  bodies  incinerated,  is 
mostly  lime  in  a  state  of  saline  combination  ; 
whilst  that  yielded  by  vegetables,  besides  lime, 
consists  of  alumina,  with  an  admixture,  greater 
or  smaller  in  amount,  of  scilica. 

The  peculiar  combinations  which  form  what 
are  called  immediate  principles,  are  much  more 
numerous  in  the  vegetable  than  in  the  animal 
kingdom,  and  are  also  generally  more  simple 
in  the  former  than  in  the  latter,  the  immediate 
principles  of  vegetables  being  mostly  ternary 
compounds,  whilst  those  of  animals  are  gene- 
rally quaternary,  nitrogen  being  added  in  these 
last  to  the  carbon,  hydrogen,  and  oxygen,  which 
form  the  organic  elements  of  the  first.  The 
immediate  principles  in  both  classes  are  divided 
into  acids  and  oxides ;  and  many  of  these  they 
have  in  common.  Vegetables,  however,  have  a 
third  order  of  substances  entering  into  their 
composition,  of  which  we  discover  no  traces 
among  animals;  these  are  the  vegetable  sali- 
fiable  bases. 

There  are  but  few  acids  which  exist  in  the 
vegetable  and  animal  kingdoms  in  common ; 
and  whilst  their  number  is  small  among  ani- 
mals, it  is  very  great  among  vegetables. 

The  hydrocyanic  acid  has  only  been  dis- 
covered in  vegetables;  when  it  is  procured 
from  animal  substances,  it  is  always  formed  un- 
der peculiar  circumstances,  or  during  their  de- 
composition. 

Of  the  organic  oxides,  some — albumen,  osma- 
zorne,  sugar — are  common  to  both  animals  and 
vegetables ;  but  they  occur  in  very  different 
proportions  in  each  :  sugar,  which  is  so  abundant 
among  plants,  is  scarcely  to  be  detected  among 
animals  ;  and  osmazome,  which  is  so  univer- 
sally distributed  among  animals,  has  only 
hitherto  been  discovered  in  a  few  fungi.  Of  the 
ternary  compounds  of  carbon,  hydrogen,  and  oxy- 
gen, such  as  starch, gum,  sugar,  the  resins,  woody 
fibre,  fixed  oils,  volatile  oils,  camphor,  extractive 
matter, <$c.  which  enter  so  largely  into  the  consti- 
tution of  vegetables,  there  are  but  a  very  few 
to  be  discovered  among  animals,  such  as  the 
sugar  of  the  milk  and  urine,  the  resin  of  the 
bile  and  of  the  urine,  the  elaine  and  stearine  of 
the  fat,  the  volatile  oily  principle  of  castoreum, 
&c.  and  the  camphor  of  cantharides. 

The  quaternary  organic  compounds  of  car- 
bon, hydrogen,  oxygen,  and  nitrogen,  which 
form  the  principal  elements  in  the  composition 
of  the  bodies  of  animals,  are,  on  the  contrary, 
very  rare  among  vegetables.  The  most  com- 
mon of  these  are  albumen,  gelatine,  fibrine, 
animal  mucus,  and  osmazome ;  the  less  com- 
mon enumerated  are  the  matter  of  the  saliva, 
caseous  matter,  urea,  and  the  pigmentary  mat- 
ter of  the  eye. 

Still  vegetables  are  not  without  several  of 
these  quaternary  compounds,  such  as  albumen 
and  osmazome,  and  they  even  possess  others 
which  are  peculiar  to  themselves,  such  as  gluten, 
the  matter  of  the  pollen  of  flowers,  indigo  and 
several  extractive  colouring  principles  ;  to  say 
nothing  of  the  whole  exclusive  class  of  salifiable 
bases,  quinia,  cinchonia,  veratria,  strychnia, 
morphia,  &c.,  &c.,  which  appear  to  be  com- 


pounds of  carbon,  united  in  large  proportion 
with  a  little  oxygen,  hydrogen,  and  nitrogen. 

Comparison  of  the  organic  composition  or 
texture  of  animals  and  vegetables. — We  find 
many  and  much  more  striking  differences  in 
the  texture  than  in  the  chemical  composition 
of  the  two  great  classes  of  organized  beings. 
Both  are  made  up  of  solids  and  fluids;  but 
with  a  few  exceptions,  the  proportion  which 
the  solid  bear  to  the  fluid  parts  is  much  greater 
in  vegetables  than  in  animals. 

The  fluids  contained  in  the  bodies  of  the 
higher  animals,  the  blood,  chyle,  spermatic 
fluid,  bile,  urine,  &c.  have  in  general  a  very 
different  character  from  those  that  constitute  the 
sap  of  the  more  perfect  vegetables,  or  that  are 
deposited  as  secretions  in  the  nectaries  and 
various  cavities  of  their  flowers,  leaf-stalks, 
stem,  &c. 

But  the  solids,  entering  into  the  composition 
of  each  class,  are  still  more  widely  dissimilar 
both  in  their  outward  and  in  their  intimate 
characters.  The  most  simple  vegetables,  the 
cryptogamia,  appear  to  consist  of  a  homo- 
geneous tissue,  forming  rounded  or  oblong  cells 
filled  with  fluids  or  a  granular  substance,  with- 
out any  trace  of  proper  tissue ;  it  is  only 
when  we  come  to  the  phanogamous  vegeta- 
bles that  we  find  any  distinction  of  tissues, 
namely,  a  cellular  and  a  tubular  tissue,  the 
whole  body  of  the  plant  being  surrounded  with 
a  distinct  integument  or  bark. 

The  cellular  tissue  of  vegetables,  whilst  still 
young,  is  soft,  homogeneous,  and  contains 
cellules  filled  with  a  fluid  often  charged  with 
globules;  when  full  grown,  this  tissue  is  made 
up  of  cells  properly  so  called,  being  spaces 
surrounded  with  solid  membranous  parietes  of 
various  forms  and  sizes  containing  different 
matters.  These  cells  appear  composed  of  vesi- 
cles placed  side  by  side  and  running  one  into 
another,  surrounding  the  spiral  and  nutrient 
vessels  of  the  stem  and  bark,  and  opening  so 
as  to  form  reservoirs  filled  with  air,  or  resinous, 
oily,  or  mucilaginous  fluids. 

The  tubular  or  vascular  tissue  of  vegetables 
occurs  under  two  different  forms — spiral  vessels, 
and  nutrient  vessels.  The  former  present 
themselves  in  great  abundance  amidst  the 
woody  fibres,  but  penetrate  also  into  the  leaves, 
and  even  into  the  stamina,  pistilla,  and  fruit. 
They  are  not  met  with  in  the  bark.  These 
vessels  seem  specially  destined  to  include  and 
conduct  the  sap,  which  from  the  root  ascends 
to  the  extreme  branches  and  leaves  of  all  vege- 
tables. The  nutrient  vessels,  so  called  from  con- 
taining a  fluid,  the  cambium  or  succus  proprius, 
different  from  the  sap,  prepared  from  this  by 
elaboration  in  the  leaves,  have  now  been  demon- 
strated in  a  great  number  of  vegetables;  they 
are  principally  contained  in  the  soft  inner  layer 
of  the  bark,  but  they  also  penetrate  every  part 
for  the  purpose  of  conveying  the  essentially 
nutritive  juice  or  blood  of  the  plant. 

These  elementary  tissues,  combined  and 
arranged  in  a  great  variety  of  modes,  constitute 
the  root,  trunk,  leaves,  flowers,  and  fruit  of  all 
vascular  vegetables ;  and  it  is  wonderful  how 
nearly  the  whole  of  this  tribe,  however  dis- 


ANIMAL. 


similar  in  their  outward  appearance,  resemble 
one  another  in  their  intimate  structure. 

The  tissues  that  enter  into  the  composition 
of  animals  are  much  more  numerous  than  those 
of  vegetables.  The  most  universally  distributed 
of  these  in  the  more  perfect  species  of  animals 
are  the  cellular,  the  vascular,  the  nervous,  and 
the  muscular,  to  which  must  be  added  the 
tendinous  or  fibrous,  the  osseous,  the  cartila- 
ginous, and  the  horny,  which  are  less  uniformly 
diffused  among  the  individuals  composing  the 
animal  kingdom. 

The  cellular  is  the  tissue  the  most  universally 
encountered  among  animals ;  it  is  demonstrable 
from  the  very  lowest  to  the  very  highest.  Its 
general  appearance  is  that  of  a  soft,  homo- 
geneous, whitish,  semi-transparent,  extensible, 
and  during  life  slightly  contractile  substance. 
It  is  permeable  to  air  and  liquids,  and  is  easily 
distended  by  either  of  these,  when  it  forms  a 
series  of  continuous  cavities  or  cells,  strangers 
at  first  to  its  constitution,  but  so  readily  pro- 
duced as  to  have  given  the  tissue  its  distin- 
guishing title.  The  cellular  tissue  is  dispersed 
abundantly  through  every  part  of  the  animal 
body  ;  it  enters  as  a  principal  element  into  the 
composition  of  many  other  tissues;  it  pervades 
the  innermost  parts  of  almost  all  organs,  and  in 
a  modified  shape  forms  a  covering  for  them 
externally;  it  may  be  said  to  constitute  the 
frame-work  of  the  organs  generally,  supporting 
them  in  their  particles  as  it  does  in  their  masses ; 
it  connects  them  together  also,  includes  and 
accompanies  the  bloodvessels  that  supply  them 
with  nourishment,  fills  the  intervals  between 
them,  and  establishes  continuity  between  every 
part  of  individual  organized  beings.  The  cellu- 
lar tissue  consists  of  filaments  and  laminae, 
mingled  and  entangled  together ;  the  interstices 
it  contains,  and  which  may  be  blown  up  into 
cells,  appear  to  be  moistened  during  life  by  a 
thin  vapour,  or  a  variable  quantity  of  serous 
fluid.* 

The  cellular  substance  appears  to  constitute 
the  element  of  the  various  membranes  encoun- 
tered in  animal  bodies  :  the  fibrous  membranes, 
the  skin,  the  mucous  membranes,  the  serous 
membranes,  and  the  synovial  membranes,  are 
all  readily  resolvable  into  cellular  tissue ;  they 
in  fact  appear  to  consist  of  this  tissue  in  dif- 
ferent states  of  condensation. 

The  vascular  is  another  tissue  extensively 
distributed  among  animals.  Three  modifica- 
tions of  the  vascular  tissue  have  been  reckoned 
by  anatomists,  occurring  respectively  in  arteries, 
veins,  and  lymphatics. 

The  third  tissue  which  is  peculiar  to  animals 
is  the  nervous.  This  may  be  held  the  most 
eminently  distinctive  of  this  class  of  organized 
beings,  as  it  is  by  its  intermedium  that  they 
exhibit  almost  all  the  faculties  which  place 
them  so  immeasurably  above  vegetables  in  the 

*  Rudolphi  assigns  as  a  distinction  between 
animal  cellular  tissue  and  that  of  vegetables,  that 
the  latter  exhibits  cells  of  a  more  or  less  regular 
form  with  firm  walls,  nothing  of  which  kind  exists 
in  the  former  :  Rudolphi  Anat.  der  Pflanzen,  S.  26, 
quoted  in  Tiedemann,  Physiologic,  Ister  Band,  S. 


scale  of  creation,  and  as,  generally  speaking, 
they  may  be  reckoned  by  so  much  the  more 
perfect  as  particular  portions  of  this  system 
are  more  fully  developed.  The  element  of 
the  nervous  tissue  is  a  soft,  whitish,  and 
little  consistent  substance,  composed  of  mi- 
nute globules  surrounded  by  a  semifluid  sub- 
stance, and  connected  together  by  a  tissue  of 
cellular  membrane  of  extreme  tenuity.  The 
globules  are  mostly  disposed  longitudinally, 
when  they  form  the  medullary  fibres  of  the 
brain  ;  surrounded  by  denser  sheaths,  they  take 
the  form  of  nerves.  In  all  the  higher  animals 
at  least,  two  orders  of  nerves  are  distinguished, 
each,  however,  being  intimately  connected  with 
the  other, — the  nerves  of  animal,  or,  better,  of 
phrenic  life,  and  the  nerves  of  organic  or  vege- 
tative life.  The  nerves  of  the  first  order  are 
connected  in  the  higher  classes  of  animals  with 
a  brain  and  spinal  cord ;  those  of  the  second 
proceed  from  small  bodies  of  a  reddish  grey 
colour,  and  irregular  shape,  named  ganglions. 
The  functions  of  the  first  take  place  with  con- 
sciousness, those  of  the  second  without  this 
mental  phenomenon.* 

The  fourth  tissue  peculiar  to  animals  is  the 
muscular.  In  several  of  the  very  lowest  tribes 
of  these,  indeed,  the  existence  of  this  tissue 
cannot  be  demonstrated ;  yet  its  actions  begin 
to  be  manifested  at  a  very  low  grade  in  the 
scale.  The  element  of  the  muscular  tissue  is 
a  fibre,  on  the  ultimate  constitution  of  which 
there  have  been  many  disputes.  The  ultimate 
muscular  fibre  would  appear  to  consist  of  a 
series  of  solid  globules  longitudinally  disposed, 
and  connected  into  larger  and  larger  fasciculi, 
which  at  length  compose  the  distinct  bundles 
denominated  muscles.  Fibrine  is  the  organic 
element  of  the  muscular  tissue.  Its  peculiar 
and  distinguishing  property  is  its  capacity  to 
contract  or  to  become  shorter,  and  to  relax  again 
or  return  in  its  quiescent  state  to  its  first  lentgh. 

The  muscles,  like  the  nerves,  are  divided 
into  two  classes  or  orders,  the  one  under  the 
influence  of  the  will,  the  other  independent  of 
it.  The  texture  is  different  in  each  of  these 
two  orders  :  in  the  voluntary  muscles,  the  fibres 
and  bundles  of  which  the  peculiar  tissue  con- 
sists are  very  regularly  disposed,  and  generally 
in  straight  and  parallel  lines  relatively  to  one 
another ;  in  the  involuntary  muscles  again,  the 
fibres  appear  of  different  degrees  of  density, 
run  parallel  or  obliquely  with  regard  to  one 
another,  are  superposed  in  layers,  intermingled 
and  entangled  like  a  kind  of  felt,  &c. 

*  Some  physiologists  have  gone  so  far  as  to 
suppose  a  rudimentary  nervous  system  among 
vegetables,  which  would  imply  consciousness  on 
their  parts  of  their  existence.  This,  at  least,  is 
a  very  doubtful  presumption,  but  we  are  not  with- 
out abstract  arguments  which  might  be  adduced  in 
favour  of  the  supposition.  How  immensely  would 
the  sphere  in  which  the  bounty  of  the  Creator 
had  displayed  itself  then  appear  enlarged  !  The 
number  of  beings  conscious  of  the  joys  of  exis- 
tence would  be  increased  a  thousand  fold  ;  and  it 
is  even  delightful  to  imagine  these  lower  parta- 
kers of  organization  with  ourselves  and  animals, 
also  enjoying  the  light  and  sunshine,  the  sequence 
of  day  and  night,  the  freshness  of  spring,  and  the 
fulness  of  autumn. 


ANIMAL. 


127 


The  fifth  tissue  which  prevails  -among  ani- 
mals is  the  fibrous.  This  is  or  may  be  divided 
into  the  tendinous  and  ligumentous.  These  are 
alike  subservient  to  the  muscular  tissue  and  to 
the  function  of  voluntary  motion.  They  con- 
sist of  fibrous,  parallel  bundles,  of  a  white 
colour  and  pearly  lustre,  of  great  strength,  and 
possessing  little  elasticity. 

The  sixth  tissue  which  is  peculiar  to  animals 
(the  first  of  those  less  universally  distributed)  is 
the  osseous.  This  forms  the  frame-work  or 
skeleton  which  gives  form  and  fixity  to  all  the 
other  parts  entering  into  the  constitution  of  the 
higher  animals.  The  essential  organic  element 
of  bone  is  a  cellular  net-work  consisting  of 
gelatine,  within  the  meshes  of  which  certain 
calcareous  salts,  the  phosphate  and  a  little 
carbonate  of  lime  especially,  are  deposited  in 
order  to  give  them  greater  solidity. 

The  cartilaginous  is  generally  reckoned  as 
the  seventh  among  the  elementary  tissues  of 
animals ;  it  may  and  has  been  very  properly 
assimilated  to  the  osseous :  the  bones  are  car- 
tilaginous at  first,  and  with  the  progress  of 
years  many  of  the  cartilages  show  a  tendency 
to,  or  do  actually  become,  converted  into  bone. 
The  cartilages  that  cover  the  articular  heads  of 
the  bones  are  almost  the  only  ones  that  show  no 
disposition  to  undergo  this  change.  The  organic 
element  of  cartilage  is  gelatine. 

Thejibro-carti/aginous  is  a  mere  modification, 
although  an  interesting  one,  of  the  cartilaginous 
or  rather  of  the  fibrous  tissue.  The  fibro-car- 
tilages  are  very  strong,  and  particularly  elastic. 

The  horny  and  calcareous  coverings  of  in- 
sects, and  the  Crustacea  have  uses  corresponding 
to  those  of  the  bones.  The  calcareous  shells 
of  the  mollusca,  too,  bear  a  certain,  though 
a  very  remote  analogy  to  the  skeletons  of  the 
higher  animals. 

The  horny  or  eighth  tissue  peculiar  to  ani- 
mals might  with  propriety  be  reckoned  among 
the  number  of  those  that  are  very  widely  dis- 
tributed. We  meet  with  it  in  the  epidermis  of 
man,  and  as  low  in  the  scale  at  least  as  the 
molluscs  and  annelides ;  it  is  the  most  universal 
clothing  provided  by  nature  for  the  bodies  of 
animals. 

So  much  for  the  simple  tissues  entering  into 
the  composition  of  animals,  to  many  of  which 
nothing  analogous  can  be  discovered  among 
vegetables.  But  these  are  by  no  means  the 
only  solid  elements  that  make  up  the  aggregate 
of  animal  bodies.  The  organs,  as  we  entitle 
them,  for  the  performance  of  certain  functions 
so  generally  encountered  among  animals, — the 
lungs,  liver,  stomach,  kidneys,  testes,  ovaries, 
&c.,  &c.,  are  so  many  peculiar  compounds  of 
the  more  simple  tissues,  occasionally  with  ad- 
ditions denominated  parenchyma,  nothing  cor- 
responding to  which  has  ever  been  discovered 
among  vegetables.  These  various  organs  are 
associated  in  animals  into  groups,  denominated 
systems,  which  severally  tend  to  the  accom- 
plishment of  the  individual  functions  mani- 
fested by  the  creature  examined, — the  teeth, 
tongue,  salivary  glands,  resophagus,  stomach, 
liver,  pancreas,  and  intestinal  canal,  constitute 
one  great  and  important  system,  subservient  to 


the  conversion  of  food  into  nourishment,  and 
the  preservation  of  the  individual ;  the  testes, 
penis,  vagina,  uterus,  and  ovaries,  in  the  two 
sexes,  compose  another  great  system  by  which 
the  species  is  continued,  and  so  on. 

Besides  these  solids  we  have  a  great  variety 
of  fluids,  which  in  animal  bodies  subserve 
various  and  important  purposes  :  we  have,  for 
instance,  the  general  nutrient  fluid  distributed 
to  all  parts  of  their  bodies,  denominated  blood. 
We  have  a  variety  of  fluids  prepared  for  aiding 
or  accomplishing  the  act  of  digestion, — the 
saliva,  gastric  juice,  pancreatic  juice,  and  bile  ; 
we  have  various  fluids  as  emunctories  of  the 
worn-out  parts  and1  particles  of  the  system, — 
the  perspiration  and  the  urine ;  and  we  have  a 
peculiar  fluid  prepared  as  a  means  of  con- 
tinuing the  species — the  spermatic  fluid.  Fluids 
corresponding  in  their  destination  to  one  or 
two  of  these  are  also  met  with  among  vege- 
tables, but  there  they  are  greatly  modified. 

Comparison  of  the  vital  manifestations,  or  ac- 
tions of  vegetables  and  animals. — In  considering 
generally  the  manifestations  of  vitality  in  vegeta- 
bles and  animals,  we  immediately  become  aware 
of  very  distinct  and  peculiar  tendencies  in  each 
class.  A  disposition  to  produce  diversity  of  parts, 
and  a  symmetrical  arrangement  of  these,  are  as 
striking  features  in  the  acts  by  which  animals 
are  evolved,  as  the  opposite  or  a  disposition  to 
reproduce  to  infinity  similar  parts  without  sym- 
metry is  a  character  inherent  in  vegetables.  The 
liver,  spl een , heart,  intestinal  canal ,  pancreas,  and 
vertebral  column,  are  the  principal  asymmetrical 
parts  in  animals  ;  the  organs  of  the  senses,  the 
lungs,  kidneys,  testes,  ovaries,  lateral  bones  of 
the  head,  and  extremities,  and  the  muscles,  are 
the  principal  symmetrical  parts  ;  and  these  seve- 
rally cannot  be  said  to  be  repeated, — they  only 
exist  in  pairs,  on  either  side  of  the  mesial  plane. 
Such  accessory  and  unessential  organs  as  hair, 
scales,  feathers,  &c.  are  the  only  ones  that 
are  found  repeated  among  animals.  The  very 
opposite  of  this  tendency  prevails  among  vege- 
tables; we  find  nothing  like  symmetrical  ar- 
rangement on  either  side  of  a  middle  plane,  and 
we  see  the  same  parts  repeated  again  and  again 
to  infinity,  so  that  any  single  part,  a  branch,  for 
instance,  becomes  an  epitome  of  the  entire 
tree. 

Another  peculiarity  in  the  mode  in  which 
the  vital  processes  build  up  vegetables  and 
animals  consists  in  the  situation  and  disposition 
assigned  to  the  various  organs  entering  into 
their  composition.  Whilst  in  plants  the  whole 
of  the  organs  destined  to  the  manifestation  of 
particular  functions, — the  leaves,  flowers,  sta- 
mina, pistilla,  roots,  &.C., — are  placed  externally, 
and  their  interior  or  trunk  is  a  mere  prop  upon 
which  these  parts  are  hung,  in  animals  the 
whole  of  the  essential  organs  destined  for  the 
preservation  of  the  individual  and  continuation 
of  the  species  are  concealed,  so  that  their  ex- 
terior is  the  shell,  their  interior  the  receptacle 
for  the  especial  lodgement  and  protection  of 
these. 

Such  diversity  in  the  arrangement  of  the 
parts  composing  vegetables  and  animals  does 
away  with  the  necessity  for  the  existence  among 


128 


ANIMAL. 


the  former  of  any  thing  like  those  central  organs 
found  in  the  latter,  which,  from  the  interior  of 
the  body,  and  generally  from  the  mesial  plane, 
send  oft'  radii  of  communication  to  every  atom 
of  the  organization,  and  prove  the  media  that 
unite  their  several  and  often  widely  separated 
parts  into  a  whole.  We  discover  nothing  like 
prolongations  from  central  organs — from  a  heart, 
an  artery,  a  stomach,  and  a  spinal  cord  or 
ganglionic  system,  among  vegetables.  Hence  the 
independence  of  the  several  parts  of  vegetables 
one  upon  another,  hence  their  susceptibility  of 
being  multiplied  by  cuttings,  and  even  of  some 
species  arising  complete  from  their  leaves. 

A  third  and  very  important  peculiarity  in 
regard  to  the  mode  in  which  the  vital  processes 
are  performed  in  the  animal  and  vegetable 
kingdom  is  that  many  take  place  with  con- 
sciousness or  knowledge  of  their  occurrence,  in 
the  one,  whilst  they  all  occur  unconsciously  in 
the  other.  In  vegetables  the  whole  of  the 
acts  whose  sum  constitutes  their  vitality  are 
perfectly  irresistible,  and  take  place  in  them 
without  their  knowledge,  and  uninfluenced  by 
their  will.  A  great  many  of  the  vital  acts,  in- 
deed, take  place  without  consciousness  among 
animals  also,  such  as  the  circulation  of  the 
blood,  the  digestion  and  assimilation  of  the 
food,  &c.,  but  the  moment  the  animal  passes 
the  sphere  of  its  individual  existence,  whenever 
it  has  to  act  beyond  itself,  we  find  conscious- 
ness of  the  action  superadded  to  the  capacity  to 
act.  The  very  lowest  animals  select  their  food, 
search  for  and  appropriate  their  aliment  as  it 
presents  itself  to  them ;  the  most  perfect  vege- 
table, on  the  contrary,  absorbs  irresistibly,  and 
without  perception  or  will,  the  materials  brought 
into  contact  with  its  roots  in  the  earth,  and  its 
leaves  in  the  air.  The  same  wide  differences 
are  apparent  in  the  act  by  which  the  species 
is  continued :  animals  search  for,  and,  by  an 
inherent  virtue  denominated  instinct,  implying 
consciousness,  distinguish  the  other  individual 
of  opposite  sex,  of  which  they  have  need  in 
order  to  procreate  their  kind ;  in  vegetables, 
on  the  contrary,  all  is  passive ;  the  pollen  or 
fecundating  powder  is  projected  or  falls  upon 
the  pistillum,  or  is  even  left  to  be  brought  into 
contact  with  this  part  by  accident,  without 
participation  in  the  act,  without  consciousness 
of  or  will  in  its  performance. 

These  two  last  named  manifestations,  the 
one  subservient  to  the  preservation  of  the  in- 
dividual, the  other  to  the  continuance  of  the  spe- 
cies, are  accompanied  with  such  circumstances 
in  animals  as  presuppose  in  them  other  two 
peculiar  faculties  :  these  are  perception  and  the 
power  of  locomotion.  To  preserve  themselves 
as  individuals  and  as  species,  they  required 
powers  which  should  make  them  acquainted  with 
and  enable  them  to  establish  relations  between 
their  own  bodies  and  the  world  beyond  them. 
By  the  faculty  of  perception,  which  may  be 
taken  as  synonymous  with  sensibility  in  its 
widest  acceptation,  an  animal  is  made  aware 
of  his  individual  existence,  as  well  as  of  that 
of  the  material  universe  without  him.  This 
faculty  also  takes  cognizance  of  all  the  internal 
sentiments,  feelings,  or  desires  of  which  by  his 


constitution  he  is  susceptible,  and  which  are 
always  in  harmony  with  the  part  he  is  destined 
to  play  in  creation.  Sensibil.ty  may  therefore 
be  denned :  the  faculty  by  which  impressions 
from  without  as  well  as  sensations,  emotions, 
and  intellectual  acts  from  within  are  perceived. 
The  organ  of  this  faculty  is  by  universal  con- 
sent admitted  to  be  the  nervous  system.  The 
faculty  itself,  as  the  above  definition  indicates, 
is  susceptible  of  being  considered  under  two 
heads  :  as  the  impressions  perceived  or  percep- 
tions come  from  without,  or  as  they  emanate 
from  within.  The  organs  of  the  senses  are  the 
media  through  which  external  impressions  reach 
the  percipient  principle  which  resides  in  the 
brain  and  medulla  oblongata  in  the  higher 
animals,  the  nervous  ganglia  in  the  lower,  and 
these  same  parts  are  the  instruments  or  elabo- 
ratories  of  the  internal  sensations.  Both  of 
these  kinds  or  modes  of  perception  were  alike 
necessary  to  the  beings  endowed  with  them. 
The  external  sensations  are  the  watchmen  of 
the  system,  admonishing  animals  of  the  pre- 
sence of  the  objects  they  require  for  their  pre- 
servation ;  the  internal  feelings,  in  like  manner, 
are  centinels  which  admonish  them  of  their 
wants  and  lead  to  the  employment  of  the  organs 
by  which  these  may  be  supplied. 

By  the  faculty  of  locomotion,  again,  an  animal 
accomplishes  all  the  promptings  of  his  inward 
nature;  he  places  himself  in  relation  with 
the  beings  and  the  things  which  he  is  ad- 
monished by  his  instincts  or  internal  faculties 
are  necessary  to  him  for  his  preservation  as 
individual  and  continuance  as  species.  Made 
aware  of  his  wants  by  perception,  by  the 
faculty  of  locomotion  he  is  enabled  to  minis- 
ter to  them.  These  two  powers,  let  us  ob- 
serve, always  exist  together;  the  one,  indeed, 
necessarily  supposes  the  other.  Sensibility  or 
perception  is  the  monitor,  locomotion  the  agent. 
Without  perception  locomotion  could  have  sub- 
served no  end  ;  without  some  capacity  of  loco- 
motion perception  would  have  been  a  vain  in- 
heritance. 

Vegetables  evidently  possess  no  power  of 
locomotion  analogous  to  that  inherent  among 
the  higher  animals, — where  the  seed  falls  there 
the  plant  springs,  there  it  attains  maturity,  and 
there  it  dies.  Neither  do  they  manifest  any 
thing  like  sensibility  in  outward  act  that  can 
be  ascribed  to  volition  or  consciousness :  their 
nature,  in  fact,  made  perception  unnecessary  to 
them ;  and  having  no  power  of  locomotion,  it 
would  have  been  useless  in  the  two  great  acts 
by  which  organized  beings  minister  to  their  pre- 
servation as  individuals  and  to  their  existence 
as  species.  Still  it  is  impossible  to  deny  every 
thing  like  capacity  of  outward  motion  to  vege- 
tables. Although  they  have  no  power  of  trans- 
porting themselves  over  the  surface  of  the  earth 
or  through  its  waters  like  animals,  many  of 
them  exhibit  motions  in  their  leaves  and  flowers 
in  relation  with  the  state  of  the  atmosphere, 
and  the  diurnal  revolution  of  the  earth ;  the 
sexual  organs  in  several  species  move  the  one 
towards  the  other;  and  about  the  foot-stalks 
and  petioles  of  the  mimosa  pudica  and  other 
plants  we  observe  particular  organs  that  con- 


ANIMAL. 


129 


tract  when  stimulated,  very  much  in  the  same 
way  as  the  muscular  fibre  among  the  higher 
animals.  Moreover,  the  motions  by  which  the 
radicle  constantly  seeks  the  ground  or  tends 
downwards  and  the  plumula  shoots  into  the 
air,  that  by  which  some  of  the  higher  phano- 
gamous  plants  twist  in  spirals  around  objects 
near  them,  and  by  which  all  preserve  one  side 
of  their  leaves  towards  the  light,  cannot  be  held 
as  accidental  or  merely  mechanical  acts.  Seve- 
ral genera  of  the  confervse  and  tremellae  even 
exhibit  such  remarkable  oscillatory  movements 
as  have  induced  different  naturalists  and  phy- 
siologists to  reckon  them  among  the  number  of 
the  animals. 

With  all  this,  however,  locomotion  among 
vegetables  is  a  very  limited  power  contrasted 
with  the  faculty  among  animals.  These  exhibit 
all  the  automatical  motions  of  vegetables,  and 
have  in  addition  a  particular  system,  the  mus- 
cular, superadded  to  their  organization,  by  which 
many  of  the  most  important  offices  of  the  eco- 
nomy are  performed :  not  only  instrumental 
in  procuring  the  food  by  which  they  are  main- 
tained, but  in  putting  into  play  the  digestive 
and  respiratory  apparatus  by  which  the  nutri- 
tive juices  are  prepared  and  assimilated,  and 
finally  distributed  among  the  higher  tribes  to 
every  part  of  the  body.  The  existence  of  this 
system  is  in  fact  one  of  the  grand  characteristics 
of  the  more  perfect  animals.  By  its  means 
they  react  upon  the  external  world  and  modify 
it  according  to  their  wants ;  by  its  means  they 
guide  their  senses  and  enlarge  the  sphere  of 
their  acquaintance  with  things  beyond  them- 
selves ;  by  its  means  they  impress  the  air  with 
the  tones  and  articulate  sounds,  or  execute  the 
signs  by  which  they  make  known  the  various 
states  of  their  affective  or  moral  and  intellectual 
being  to  one  another ;  finally,  by  its  means  the 
sexes  approximate,  and  those  acts  take  place 
which  lead  to  the  engenderment  of  new  indivi- 
duals and  the  continuance  of  species. 

The  best  informed  among  physiologists,  how- 
ever, do  not  confine  the  motions  of  all  animals 
to  the  act  of  the  particular  tissue  we  denominate 
muscular.  The  polypes  and  many  even  of  the 
massy  acalephs,  to  say  nothing  of  the  smaller 
infusories,  rotifers,  &c.  though  they  move 
freely,  cannot  be  shown  to  possess  muscular 
fibres  in  their  constitution ;  neither  indeed  can 
any  nervous  system,  upon  which  muscular 
contractions  and  voluntary  motion  have  always 
been  held  dependent,  be  demonstrated  in  these 
creatures.  It  is  consequently  probable  that  the 
means  by  which  spontaneous  motion  takes 
place  in  these  lower  animals  are  peculiar,  as 
indeed  we  must  acknowledge  the  evident  mo- 
tions which  occur  under  many  other  circum- 
stances in  the  world  of  organization  to  be. 

But  let  us  now  turn  to  the  special  manifesta- 
tions of  vitality  of  the  two  great  classes  of 
organized  beings  we  are  engaged  in  examining. 
These  we  shall  consider  in  the  following  order, 
which  is  also  that  we  have  adopted  in  contrast- 
ing the  manifestations  of  activity  of  unorganized 
and  oiganized  beings, — namely,  origin  or  repro- 
duction, nutrition  or  self-preservation,  changes 

VOL.  I. 


undergone  during  the  period  of  existence,  or 
the  ages,  and  death,  or  end. 

ORIGIN,  or  the  acts  by  which  species  are  con- 
tinued.— Vegetables  and  animals  alike  derive 
their  origin  from  a  birth  or  genesis  accom- 
plished in  two  different  modes,  either  without 
the  concurrence  of  opposite  sexes,  or  with  such 
a  concurrence.  When  organized  beings  are  pro- 
duced without  the  concurrence  of  opposite 
sexes,  the  parent  either  divides  into  several 
pieces,  each  of  which  becomes  an  independent 
individual,  or  throws  out  burgeons  or  buds 
from  its  surface,  which,  being  detached  in  due 
season  exist  as  self-sufficing  types  of  the  spe- 
cies. When  organized  beings  spring  from  the 
concurrence  of  sexes,  again,  two  sets  of  organs 
minister  to  the  generation,  the  one  denominated 
male,  supplying  a  fecundating  matter,  the  other 
entitled  female,  furnishing  a  germ,  which  sub- 
sequently to  its  impregnation  by  the  male 
organ  undergoes  a  series  of  evolutions  that  end 
in  the  issue  of  an  individual  resembling  the 
parents,  and  fitted  by  its  own  acts  to  preserve 
itself  and  to  continue  its  kind. 

Both  of  these  modes  of  reproduction  are 
common  to  vegetables  and  animals.  Confervae 
and  polypi  alike  exhibit  the  first  mode,  almost 
without  a  difference  :  buds  or  sprouts  arise 
from  the  surface  of  both ;  these  adhere  for  a  time, 
acquire  a  certain  size,  and  are  finally  detached  to 
become  independent  beings.  Again,  the  polype 
divided  into  several  pieces,  gives  origin  in  each 
of  these  parts  to  distinct  polypi,  exactly  as  the 
cuttings  of  vegetables  take  root  and  grow  into 
perfect  trees,  shrubs,  &c. 

The  second  mode  of  reproduction — that  by 
the  concurrence  of  sexes,  or  of  organs  deno- 
minated respectively  male  and  female, — is  also 
exhibited  by  vegetables  and  animaV;  indiffer- 
ently; but  there  are  numerous  circumstances 
distinguishing  this  manner  of  reproduction  in 
the  two  classes  of  organized  beings.  In  the 
first  place,  the  sexual  organs  do  not  exist  from 
the  earliest  period,  and  during  the  whole  course 
of  the  life  of  vegetables,  as  they  do  in  animals ; 
the  sexual  organs,  in  fact,  only  occur  among 
vegetables  at  the  time  of  flowering,  and  perish 
whenever  the  end  of  their  evolution  has  been 
accomplished,  never  serving  oftener  than  once 
for  the  generative  act.  The  sexual  organs  of 
all  animals,  again,  that  live  for  more  than 
a  year,  suffice  repeatedly  for  their  office ;  and 
if  they  are  not  required  to  accomplish  this 
oftener  than  once  in  the  short-lived  tribes,  it  is 
probably  from  no  inherent  incapacity  to  serve 
again,  or  any  destruction  of  the  organs  them- 
selves, but  simply  because  the  term  of  existence 
of  the  organism  of  which  they  formed  a  part  is 
complete,— they  perish  with  the  system  to 
which  they  belonged. 

Another  grand  though  not  an  invariable  dis- 
tinction between  vegetables  and  animals  is  the 
mode  in  which  the  sexes,  or  sexual  organs — for 
these  may  be  taken  as  synonymous  terms — are 
distributed  among  the  individuals  of  each  class. 
Speaking  generally,  it  may  be  said  that  the 
sexual  organs  are  as  commonly  divided  be- 
tween two  individuals  among  animals  by  whom 


130 


ANIMAL. 


the  species  is  represented,  as  they  are  confided 
to  one  among  vegetables,  which  is,  therefore, 
singly  the  type  of  its  kind.  In  both  classes, 
indeed,  there  are  exceptions  to  this  general  law : 
the  flowers  of  all  vegetables  do  not  contain 
stamina  and  pistilla,  or  male  and  female  organs, 
neither  are  the  opposite  sexes  invariably  repre- 
sented by  two  different  individuals  among 
animals.  In  many  plants  the  male  organs  are 
known  to  exist  in  one  flower,  the  female  in 
another,  but  both  developed  on  the  same 
branch ;  in  many  others,  again,  they  exist  on  dif- 
ferent sterns,  and  are  often  evolved  widely  apart 
from  one  another.  In  the  same  manner,  many 
of  the  lower  tribes  of  animals  include  within 
their  individual  organisms  male  and  female 
organs;  this  is  the  lasewith  several  tribes  of 
the  genus  mollusca,  gasteropoda,  the  helix, 
limax,  and  lepas,  for  instance,  with  the  whole 
of  the  extensive  classes  of  the  annelida,  en- 
tozoa,  echinodermata,  &c. 

But  though  there  be  resemblance  to  this 
extent  among  vegetables  and  animals  in  regard 
to  organs,  in  the  act  by  which  fecundation 
is  accomplished  there  is  a  wide  and  essential 
difference ;  for  whilst  vegetables  impregnate 
themselves,  or,  rather,  whilst  the  impregnation 
of  vegetables  is  a  purely  passive  process,  with- 
out perception  of  or  concurrence  in  its  accom- 
plishment on  their  parts, — the  pollen  of  the 
anthers  of  those  flowers  that  have  male  and 
female  organs  being  simply  shed  upon  the 
pistilla,  the  impregnation  of  animals,  so  far  as 
our  knowledge  goes,  appears  to  be  almost  as 
generally  a  consequence  of  a  connexion  be- 
tween two  different  individuals,  and  of  volition 
with  consciousness  on  their  several  parts. 
Although  many  animals  have  both  male  and 
female  parts  included  within  the  same  organism, 
it  would  seem  that  comparatively  few  have  the 
power  of  impregnating  themselves :  two  in- 
dividuals of  the  like  species  meet,  and  give 
and  take  reciprocally  ;  so  that  there  is,  in  fact, 
much  less  difference  between  the  highest  and 
the  lowest  tribes  of  the  animal  kingdom  in  the 
essentials  by  which  races  are  continued,  than 
at  first  sight  appears,  much  less  certainly  than 
there  is  between  the  vegetables  and  animals 
that  are  most  nearly  allied.  The  modes  in 
which  fecundation  takes  place  in  vegetables  at 
large,  and  in  animals  probably  without  exception, 
are  inherently  and  essentially  distinct :  an  her- 
maphrodite animal  is  still  a  very  different  thing 
from  an  hermaphrodite  flower. 

Another  difference  between  vegetables  and 
animals,  less  important,  indeed,  but  still  in- 
teresting, lies  in  the  number  of  the  organs  pos- 
sessed by  each  destined  for  the  continuation  of 
the  species.  In  many  vegetables  the  organs 
are  single,  one  flower  being  taken  as  a  repre- 
sentative of  the  sexes ;  in  a  much  larger  pro- 
portion of  plants,  however,  the  organs  are  mul- 
titudinous. Among  animals,  on  the  contraiy, 
with  a  few  exceptions  in  the  very  lowest  tribes, 
the  asterias,  &;c.  where  they  are  multidinous, 
the  essential  male  and  female  organs,  the  testes 
and  ovaria,  exist  singly  or  in  pairs  only. 

A  third  diversity,  and  one  that  is  striking 


and  almost  universal,  between  those  species  of 
plants  and  animals  in  which  the  sexes  are 
represented  by  two  individuals,  lies  in  the 
difference  of  conformation,  size,  and  general 
character  of  the  individuals  in  the  one  class, 
and  their  perfect  similarity  in  the  other.  There 
are  very  few  dioecious  plants  the  males  of 
which  are  distinguishable  from  the  females; 
there  are  very  few  tribes  of  animals,  on  the 
contrary,  in  which  the  distinction  of  sex  is  not 
extremely  apparent,  the  males  being  generally 
larger,  stronger,  and  more  courageous ;  the 
females  smaller,  more  delicately  formed,  and 
more  timid  in  their  disposition.* 

A  fourth  distinction  which  deserves  to  be 
noted  betwixt  animals  and  vegetables  is  in  the 
diversity  of  the  act  by  which  the  new  being 
is  separated  from  the  parent,  and  commences 
its  independent  existence.  The  period  at  which 
this  happens,  indeed,  is  determinate,  and  fixed 
in  both  alike,  but  it  is  accompanied  with  con- 
sciousness among  animals,  whilst  it  is  alto- 
together  unwittingly  accomplished  among  ve- 
getables. 

From  this  review  of  the  mode  in  which 
animals  and  vegetables  are  called  into  be.ng, 
or  of  the  acts  which  lead  to  their  creation,  the 
main  and  most  striking  differences  observable 
in  the  two  classes  are  these  :  whilst  in  vegeta- 
bles the  whole  of  the  acts  that  constitute  re- 
production,— the  union  of  the  sexes,  the  fe- 
cundation of  the  ovum,  and  the  birth  of  the 
new  being  are  accomplished  without  the  will 
and  without  the  consciousness  of  the  indi- 
vidual, but  irresistibly  and  necessarily,  they 
are  left  in  some  particulars,  at  least,  to  the 
will,  and  take  place  with  the  consciousness 
of  the  individuals  among  animals. 

NUTRITION,  or  the  acts  by  ivhich  the  indi- 
vidual is  preserved. — Every  thing  in  nature 
changes,  and  organized  beings  only  con- 
tinue their  existence  with  their  aptitudes 
to  manifest  the  acts  that  draw  so  wide  a 
line  of  demarcation  between  them  and  unor- 
ganized bodies,  by  a  perpetual  renewal  or  re- 
composition,  and  as  incessant  a  rejection  or 
decomposition  of  their  elements.  Nutrition  is, 
therefore,  at  least,  a  two-fold  act,  implying 
absorption  or  appropriation  of  nutritive  matter, 
and  excretion  or  rejection  of  the  old  and  worn- 
out  particles  that  have  already  served  their 
office  in  the  economy  :  it  consists,  in  fact,  as 
we  have  said,  of  an  incessant  decomposition 
and  reconstruction  of  the  fabric  of  the  living 
organized  being.  Nutrition,  however,  is  a  very 
comprehensive  term,  and  includes  the  whole  of 
the  vital  acts  by  which  the  individual  continues 

*  One  of  the  most  striking  exceptions  to  this  law 
occurs  among  some  especially  of  the  smaller  species 
of  the  birds  of  prey.  In  many  of  these  the  female 
is  much  more  powerful,  heavier,  and  even  more 
courageous  than  the  male.  The  care  of  the  off- 
spring, by  one  of  nature's  ordinances,  devolving 
principally  upon  the  female,  the  supply  of  flesh 
for  the  brood — a  supply  procured  by  violence — 
might  often  have  failed  had  she  not  in  these 
tribes  been  provided  with  superior  strength  and 
courage  to  insure  its  regularity  and  abundance. 


ANIMAL. 


131 


its  existence, — namely,  among  the  higher  tribes 
of  living  things,  the  absorption  or  ingestion  of 
food  or  alimentary  matter ;  the  preparation  of 
this  food  by  the  processes  of  digestion  and 
respiration ;  the  distribution  of  the  nutritive 
matter  fitted  for  its  ends,  to  every  part  of  the 
system  by  means  of  a  circulation ;  the  conver- 
sion of  the  nutritive  matter  into  the  solids 
and  fluids  or  proper  substance  of  the  indi- 
vidual, and  finally  the  depuration  and  rejection 
of  the  worn-out  parts  and  particles  by  means 
of  certain  secreting  organs.  These  various  pro- 
cesses in  themselves  will  be  particularly  con- 
sidered in  the  article  NUTRITION,  to  which  the 
reader  is  referred.  Meantime  let  us  contrast 
these  different  functions  as  they  manifest  them- 
selves in  each  of  the  two  grand  divisions  of 
the  organized  world. 

Assumption  of'  aliment.  —  The  earth  and 
the  atmosphere,  and  the  carbonic  acid 
and  water  they  contain,  are  the  sources 
whence  vegetables  derive  their  food.  Here 
they  find  aliment  ready  prepared  for  their  use, 
or  rather,  as  passive  agents,  they  depend  on 
the  earth  and  the  atmosphere  for  a  supply 
of  the  elements  required  for  their  continuance. 
Those  physiologists  are  now  admitted  to  have 
been  mistaken  who  supposed  that  the  food  of  ve- 
getables was  furnished  by  the  inorganic  earth, 
air,  and  water,  with  which  their  roots  and 
leaves  are  in  relation ;  more  accurate  experi- 
ments have  shown  that  plants  are  as  dependent 
as  animals  on  supplies  of  substances  that  have 
once  had  life  for  their  support.  When  plants 
are  made  to  grow  in  pure  earth  and  in  distilled 
water,  they  appear  to  do  so  by  a  kind  of  de- 
composition of  themselves,  one  part  perishing 
and  affording  food  to  that  which  continues  to 
live.  To  base  a  distinction  between  animals 
and  vegetables,  consequently,  on  the  presump- 
tion that  the  one  lived  on  organic,  the  other  on 
inorganic  substances,  was  incorrect :  animals 
and  vegetables  are  alike  in  this  respect ;  both 
feed  upon  organized  matter,  and  this  not  al- 
ways or  necessarily  in  a  state  of  decomposition, 
as  we  observe  among  parasitic  tribes,  which 
subsist  on  the  living  juices  of  the  individuals 
they  cling  to.  The  food  of  animals,  however, 
may  be  stated  generally  to  be  both  more  various 
and  also  more  complex  in  its  chemical  com- 
position than  that  of  vegetables,  and  whilst 
vegetables  take  all  their  food  in  a  liquid  shape, 
animals  much  more  commonly  live  on  a  mix- 
ture of  solids  and  fluids. 

The  assumption  of  food  by  vegetables  and 
animals  takes  place  under  very  different  cir- 
cumstances. In  vegetables  it  is  necessary  and 
independent  of  the  individual;  it  is  also  in- 
cessant ;  and,  farther,  it  takes  place  from  the 
external  surface,  inasmuch  as  it  is  with  this 
that  the  materials  which  supply  the  nutriment 
are  in  contact. 

Animals,  however,  have  not  generally  their 
food  prepared  for  their  use  brought  into  con- 
tact with  their  bodies,  neither  are  they  passive 
in  its  assumption;  they  have  mostly  to  search 
for  it  abroad,  and  are  provided  with  special 
organs  for  this  purpose.  The  act  by  which 
they  take  it  is  not  necessary,  neither  is  it  in- 


cessant. They  have  also  to  select  their  food, 
and  are,  therefore,  furnished  with  faculties 
which  guide  them  in  their  choice;  namely,  taste 
and  smell.  Lastly,  the  absorption  of  the  truly 
nutritious  matter  is  accomplished  from  their 
interior,  the  crude  material  assumed  as  food 
having  been  first  prepared  by  elaboration  in  a 
cavity  called  a  stomach. 

As  organized  living  beings,  the  soundest 
philosophy  and  best  ordered  experiments  lead 
us  to  infer  that  there  is  little  if  anything  me- 
chanical in  the  mode  in  which  either  vegetables 
or  animals  absorb  nutriment.  The  absorption 
of  their  aliment  by  vegetables  is  influenced  by 
the  seasons,  their  state  of  health  or  disease, 
their  age,  and  external  circumstances  gene- 
rally,— the  temperature,  state  of  dryness  or 
moisture,  &c.  of  the  air  with  which  they  are 
surrounded;  the  cause  of  the  absorption  of 
their  food  by  vegetables  is,  therefore,  some- 
thing different  from  what  is  called  capil'ary 
attraction,  or  the  law  by  which  fluids  ascend 
in  tubes  of  small  calibre. 

The  proper  passage  of  the  nutriment  into  the 
bodies  of  animals  occurs  from  their  interiors, 
and  in  a  very  large  proportion  (probably  in 
every  somewhat  perfect  member)  of  the  class, 
by  means  of  a  special  set  of  vessels  denomi- 
nated lacteals  or  lymphatics,  no  system  cor- 
responding to  which  exists  among  vegetables. 

The  very  lowest  tribes  of  the  animal  king- 
dom, the  entozoa,  acalephse,  polypi,  &c.  having 
no  proper  vessels  of  any  kind,  the  cellular 
membrane  of  which  they  consist  absorbs,  and 
by  virtue  of  a  peculiar  vital  process,  distributes 
the  nutritive  juices  extracted  from  the  matters 
received  into  the  stomach  and  alimentary  canal 
to  all  parts  of  their  bodies.  Those  tribes  of 
animals  which  have  naked  skins  have  the  faculty 
of  absorbing  by  their  exterior  also. 

Still  less  than  in  vegetables,  can  we  suppose 
that  the  process  by  which  in  animals  nutriment 
is  ultimately  absorbed  into  the  body,  whether 
from  the  exterior  or  the  interior,  is  akin  to 
mechanical  or  capillary  attraction.  The  tissues 
of  which  animal  bodies  consist  are,  indeed, 
permeable  to  fluids,  but  this  does  not  explain 
the  collection  of  these  fluids  in  so  many  tribes 
into  particular  canals,  and  still  less  does  it 
solve  the  problem  of  the  continued  motion 
onwards  in  determinate  directions  within  these 
channels. 

Absorption  of  alimentary  and  other  matters, 
therefore,  in  both  of  the  grand  divisions  of  the 
organized  world,  must  be  held  as  a  vital  act, — 
as  one  of  the  particular  laws  superadded  in 
organized  beings  to  the  general  system  of  phy- 
sico-chemical ordinances  that  rule  the  universe 
and  its  parts.  This  quality  is  common  to 
vegetables  and  animals. 

By  far  the  greater  number  of  animals  have 
one  or  more  special  openings,—  a  mouth  or 
mouths,  by  which  they  take  in  such  sub- 
stances as  are  fitted  for  their  nourishment. 
Even  the  greater  number  of  animals  as  low  in 
the  scale  as  the  infusoria,  have  been  recently 
demonstrated  (by  Ehrenberg)  to  be  provided 
with  an  opening  of  this  kind.  Several,  how- 
ever, seem  to  receive  aliment  by  the  way  of 


ANIMAL. 


absorption  alone.  The  mouth  is  a  cavity  of 
extremely  varied  character  and  construction 
adapted  universally  to  the  circumstances  in 
which  animals  exist.  Nothing  analogous  to  a 
mouth  is  met  with  in  any  vegetable. 

The  food  having  been  selected  and  seized  is 
next  transferred  to  the  cavity  in  which  it  un- 
dergoes an  elaboration  that  fits  it  to  be  received 
into  the  proper  system  of  the  animal  and  con- 
verted into  its  own  substance.  We  do  not 
find  anything  like  the  pouch  denominated  a 
stomach  in  any  member  of  the  vegetable  king- 
dom. The  matter  fitted  for  its  nourishment, 
absorbed  by  the  root,  is  transmitted  to  the 
stem,  and  from  thence  makes  its  way  into  the 
leaves  of  the  vegetable.  It  does  not  pass  un- 
changed, however,  from  the  earth  into  the  root, 
or  at  least  it  has  advanced  but  a  very  short  way 
on  its  course  to  the  leaves,  before  it  is  found 
to  have  undergone  certain  changes,  which  are 
also  known  to  be  greater  in  amount  as*  it  is 
examined  at  a  greater  height  or  distance  from 
the  root.  Although  growing  from  the  same 
soil  too,  the  sap  of  vegetables,  i.  e.  the  fluid 
which  is  passing  upwards  through  the  woody 
fibres,  is  found  to  be  universally  different. 
Whether  the  peculiar  qualities  thus  acquired 
by  the  simple  moisture  holding  certain  salts, 
&c.  in  solution,  which  is  the  food  all  vege- 
tables derive  through  their  roots,  be  the  effect 
of  vital  elaboration  within  the  cells  of  the 
woody  fibre,  or  result  from  an  admixture  of  the 
cambium  or  fluid  which  has  already  undergone 
assimilation  in  the  leaves,  is  still  uncertain. 
We  are  inclined  to  believe  that  a  process  ana- 
logous to  digestion  does  actually  take  place 
within  the  woody  conduits  of  the  sap  of  vege- 
tables ; — why  should  it  not,  or  why  should 
any  new  properties  acquired  by  matters  sub- 
jected to  the  influence  of  the  peculiar  laws 
of  vitality  be  held  as  resulting  from  mere  ad- 
mixture ? 

The  very  same  thing,  in  fact,  happens  among 
the  lowest  tribes  of  animals  which  takes  place 
in  all  vegetables :  the  substances  fitted  for  their 
nourishment  penetrate  or  are  absorbed  into 
their  systems,  and  are  there  assimilated  without 
the  intermedium  of  any  special  apparatus. 
We  mount  but  a  very  short  way  in  the  scale 
of  the  animal  creation,  however,  before  we 
meet  with  a  peculiar  pouch,  destined  for  the 
reception  of  the  aliment,  and  accomplishment 
of  the  first  steps  in  the  processes  by  which,  in 
the  more  perfect  animals,  it  is  finally  assimi- 
lated. This  pouch  is  the  stomach,  and  with 
the  rest  of  the  digestive  apparatus  with  which 
it  is  connected,  is  in  intimate  and  uniform  re- 
lationship with  the  kind  of  food  upon  which 
animals  are  led  by  their  instincts  to  live. 

All  the  accessaries  of  the  assimilating  cavity 
or  stomach  which  we  find  in  animals,  from 
the  organs  of  sense  that  guide  them  in  their 
choice 'of  aliment,  to  the  lips  that  seize  it,  the 
teeth  or  jaws  that  bruise  it  or  destroy  its 
vitality,  the  muscular  actions  by  which  it  is 
swallowed,  and  the  chemico-vital  processes  by 
which  it  is  dissolved,  and  the  purely  vital  sen- 
sibilities by  which  such  parts  as  are  proper  for 
"nourishment  are  retained,  and  such  as  are  im- 


proper for  this  purpose  are  expelled, — all  of 
these  are  wanting  among  vegetables. 

There  are  yet  other  processes  which  form  an 
essential  item  in  the  acts  by  which  organized 
beings  universally  continue  their  existence, 
which  it  is  necessary  we  should  include  in  this 
summary  of  the  common,  particular,  and  dis- 
tinguishing attributes  of  vegetables  and  ani- 
mals. One  of  the  most  important  of  these  is 

Respiration. — The  leaves  in  the  more  per- 
fect vegetables  are  the  instruments  of  respi- 
ration ;  their  place  is  supplied  by  the  general 
surface  in  those  plants  that  are  aphyllous.  Vege- 
tables that  live  in  air  act  immediately  by 
means  of  their  respiratory  organs  upon  the 
ambient  medium  ;  those  that  live  in  water, 
upon  the  air  held  in  solution  by  the  fluid 
around  them. 

Vegetables  are  well  known  to  exhale  .abun- 
dantly from  the  surface  of  their  leaves,  or 
stems,  in  case  they  have  no  leaves.  The  mat- 
ter exhaled  is  principally  water.  They  have 
also  the  farther  property  of  decomposing  one 
of  the  elements  of  atmospheric  air,  namely, 
carbonic  acid  gas.  In  the  sunshine  the  leaves 
of  vegetables  fix  the  carbon  which  enters  into 
the  composition  of  this  gas,  and  set  the  oxy- 
gen at  liberty ;  in  the  dark,  however,  a  very 
different  process  goes  forward  ;  they  then 
actually  absorb  oxygen  and  exhale  carbonic 
acid  gas ;  the  balance,  however,  in  the  aggre- 
gate is  not  equal  between  these  opposite  pro- 
cesses, a  much  larger  quantity  of  carbon  being 
fixed  by  the  decomposition  of  carbonic  acid 
gas  and  oxygen  set  at  liberty,  than  there  is  of 
oxygen  absorbed  and  carbonic  acid  gas  set  free. 
These  acts  are  essential  to  the  life  and  health 
of  vegetables ;  their  end  and  object  appear  to 
be  the  preparation  of  their  proper  nutritive 
fluids  or  cambium  :  the  sap  which  reached  the 
leaves,  colourless,  not  coagulable,  without  glo- 
bules, mere  water  holding  carbonic  acid, 
acetic  acid,  a  muco-saccharine  matter,  and 
various  salts  in  solution,  is  in  them  converted 
into  a  greenish  fluid,  partly  coagulable,  and 
full  of  globules,  which  special  vessels  then 
distribute  for  the  growth  and  maintenance  of 
the  different  parts. 

The  respiratory  act  is  necessary,  and  goes  on 
without  the  aid  or  concurrence  of  the  indi- 
vidual among  vegetables. 

Animals  are  no  less  dependent  than  vege- 
tables on  communication  with  the  air  of  the 
atmosphere,  either  immediately  or  mediately, 
for  a  continuance  of  their  existence,  or  the 
manifestation  of  those  acts  whose  sum  con- 
stitutes their  lives.  In  the,  very  lowest  tribes 
the  communication  between  them  and  the  air 
of  the  atmosphere  takes  place  over  the  surface 
of  the  body  generally,  without  the  intermede 
of  any  particular  organ  or  organs  for  the  pur- 
pose. The  fluids  absorbed  into  their  bodies 
are  brought  into  contact  with  the  atmospheric 
air  in  those  points  where  they  approach  the 
external  surface,  and  there  appear  to  undergo 
the  changes  necessary  to  fit  them  for  being 
convertecf  into  the  substance  of  the  animals 
themselves.  Simple  as  this  process  may  ap- 


ANIMAL. 


133 


pear,  slender  as  the  means  of  accomplishing  it 
may  seem  to  be,  it  is  nevertheless  essential : 
interrupted  for  any  length  of  time,  the  animal 
inevitably  perishes.  A  process  of  such  im- 
portance, as  may  be  imagined,  is  not  long  left 
without  its  appropriate  and  special  apparatus. 
This  varies  extremely  in  its  structure,  in  the 
different  tribes  of  animals,  and  according  to  the 
circumstances  surrounded  by  which  they  live. 
Some  have  lungs,  branchiae  or  gills,  and 
tracheae  opening  by  spiracula,  of  infinitely  va- 
ried construction. 

Respiration  is  also  carried  on  vicariously 
in  a  very  large  proportion  of  animals,  if  not 
perhaps  in  all  to  a  certain  extent,  by  means 
of  the  skin,  and  in  some  even  by  the  instru- 
mentality of  the  alimentary  canal. 

The  changes  effected  in  the  atmospheric 
air  by  the  respiratory  apparatus  of  all  animals 
are  similar,  but  they  differ  from  those  that  are 
produced  by  the  corresponding  implements  in 
vegetables :  the  proportion  of  oxygen  it  con- 
tains universally  diminishes,  and  the  quantity 
of  carbonic  acid  gas  it  holds  in  solution  as 
invariably  increases  in  amount.  A  quantity  of 
water  or  of  watery  vapour  is  at  the  same  time 
thrown  off.  This  is  exactly  the  opposite  of 
what  we  have  seen  to  be  the  effect  of  respi- 
ration among  vegetables;  in  these  the  quantity 
of  oxygen  is  augmented,  whilst  that  of  car- 
bonic acid  gas  is  diminished.  The  nutritive 
fluids  newly  prepared  by  the  apparatus  of 
digestion,  or  that  have  already  gone  the  round 
of  the  system,  are  by  a  variety  of  means  ex- 
posed, in  the  special  or  common  apparatuses 
mentioned,  to  the  influence  of  the  atmospheric 
air,  from  the  contact  of  which  they  undergo 
certain  important  and  often  manifest  changes 
that  fit  them  for  their  ultimate  office  in  the 
animal  economy, — the  maintenance  of  its 
parts,  with  their  inherent  capacities  to  execute 
the  various  functions  imposed  upon  them. 

The  respiratory  act  among  animals  takes 
place  with  the  knowledge  and  with  the  assist- 
ance and  implied  will  of  the  individual. 
Animals  are  informed  of  the  necessity  of  re- 
spiring by  the  feeling  of  a  want,  an  uneasiness, 
just  as  they  are  admonished  of  the  necessity 
of  taking  aliment  by  the  painful  sensations 
denominated  hunger  and  thirst. 

The  essence  of  respiration  in  the  two  grand 
classes  of  organized  beings  would  therefore 
appear  to  be  different,  and  might  be  made 
the  ground  of  a  definitive  distinction  between 
the  members  of  each  kingdom.  Carbon  is  the 
object  for  which  the  respiration  of  plants  is 
instituted  ;  oxygen  the  end  for  which  re- 
lations are  established  between  animals  and  the 
atmosphere.  Another  grand  difference  be- 
tween the  respiration  of  plants  and  animals  is 
the  involuntanness  of  the  act  in  the  one,  and 
its  voluntariness  in  the  other,  its  occurrence 
with  unconsciousness  in  the  one,  and  with  con- 
sciousness in  the  other. 

The  nutrient  juices  thus  prepared  have 
now  to  be  distributed  ;  this  is  done  by  means 
of  a  peculiar  motion  impressed  upon  the  fluids 
in  virtue  of  a  vital  law  with  the  nature  of 


which  we  are  still  very  imperfectly  acquainted. 
Let  us  use  the  word  circulation  in  a  sense 
implying  motion  generally,  not  motion  in  a 
circle  to  designate  the  act  by  which  in  the 
organized  world  the  nutritive  juices  are  dis- 
tributed through  the  frames  of  the  objects 
composing  it. 

Circulation. — There  can  be  no  doubt  of  the 
existence  of  a  circulation  among  vegetables  ;  in 
many  species  currents  in  opposite  directions 
have  even  been  seen  with  the  aid  of  the  micro- 
scope, and  this  not  only  among  the  lowest  and 
most  simple  in  their  structure  of  the  class,  but 
also  in  the  highest  and  most  complicated.  The 
circulation  of  vegetables  appears  to  take  place 
within  two  different  congeries  of  vessels,  ex- 
tremely numerous,  and  disposed  according  to 
their  nature  in  different  parts  of  the  plant.  The 
vessels  that  pump  or  transmit  the  sap  from  the 
roots  to  the  leaves,  for  instance,  as  we  have 
already  had  occasion  to  state,  run  within  the 
woody  parts  of  plants  ;  those  that  receive  the 
modified  juices  of  the  leaves,  again,  take  their 
course  downwards  within  the  bark.  These  two 
sets  of  vessels  anastomose  within  the  substance 
of  the  leaves,  but  no  where  else ;  the  second 
set  can  alone  be  said  to  have  a  distribution 
throughout  the  vegetable,  for  every  part  appears 
to  depend  on  them  for  its  supply  of  nourish- 
ment, even  the  extreme  points  of  the  roots, 
which  were  themselves  the  first  instruments  in 
collecting  the  aliment  still  unfit  for  the  purposes 
of  nutrition.  The  best  informed  vegetable 
physiologists  are  of  opinion  that  the  nutritive 
fluid  once  sent  off  from  the  leaves  nev^r  finds 
its  way  back  to  these  organs  again  ;  it  is  ab- 
sorbed or  fixed  by  the  different  parts  or  struc- 
tures to  which  it  is  distributed,  ministering  to 
their  increment  generally,  and  enabling  each  to 
manifest  its  specific  function  in  the  vegetable 
economy. 

In  this  motion  of  the  fluids  of  vegetables  it 
is  evident  that  there  is  little  analogous  to  what 
we  find  within  the  bodies  of  animals  somewhat 
elevated  in  the  scale.  But  let  us  first  cast 
a  hasty  glance  at  what  does  take  place  within 
this  other  division  of  the  organic  kingdom  be- 
fore instituting  a  comparison  between  the  func- 
tions of  circulation  in  the  two.  All  animals, 
from  the  mammalia  downwards  to  the  entozoa, 
— birds,  reptiles,  fishes,  the  mollusca,  Crustacea, 
arachnida,  insecta,  and,  among  the  radiata,  the 
holothuriae,  echini,  and  asteriae,  include  within 
their  organisms  particular  canals  or  vessels  for 
containing  and  distributing  their  nutrient  juices, 
and  within  which,  moreover,  these  are  in  motion 
in  a  circle.  In  the  acalephae  we  still  find  canals 
branching  off  from  the  digestive  cavity  and  dis- 
tributing the  nourishment  there  prepared  to  the 
different  parts  of  the  body  :  in  these,  however, 
we  no  longer  find  any  contrivance  for  establish- 
ing a  circular  motion  in  the  nourishing  juices. 
Still  lower  in  the  scale,  among  the  polypes  and 
actinese,  for  example,  we  discover  no  branched 
appendages  or  canals  for  the  distribution  of  the 
nutrient  fluids ;  those  prepared  in  the  stomachs 
of  the  animals  appear  to  penetrate  their  sub- 
stance directly,  and  to  permeate  the  homo- 
geneous cellular  tissue  of  which  they  consist, 


134 


ANIMAL. 


In  the  tribes  which  have  a  circulation,  in 
the  strict  sense  of  that  word,  we  find  two  or- 
ders of  vessels, — arteries  and  veins,  in  which 
the  nutritive  juices,  or  blood,  moves  respec- 
tively in  opposite  directions,  from  the  trunks 
towards  the  branches  in  the  one,  from  the 
branches  towards  the  trunks  in  the  other. 
These  vessels  anastomose  freely  by  their  ex- 
tremities, which  terminate  and  originate  in 
every  part  of  the  body,  and,  farther,  meet  in  a 
common  central  cavity,  which,  when  furnished 
with  muscular  parietes,  is  entitled  heart.  With- 
in the  circle  of  vessels  thus  established,  the 
nutrient  fluid  of  animals  is  in  perpetual  or  next 
to  perpetual  motion  during  the  term  of  their 
lives.  In  the  higher  classes  the  main  agent  in 
producing  this  motion  is  the  central  organ  in 
which  the  veins  and  arteries  meet;  but  it  is  not 
the  only  cause  of  the  circulation,  this  act  going 
on  vigorously  in  circles  and  in  situations 
wherein  the  heart's  action  can  have  very  little 
influence,  and  in  some  tribes  where  the  heart 
is  even  altogether  wanting. 

The  circulation  in  the  greater  number  of 
animals,  however,  is  a  more  complicated  pro- 
cess than  that  which  has  just  been  described  ; 
it  consists,  in  fact,  of  two  parts  perfectly  dis- 
tinct from  each  other;  one  whereby  the  blood 
is  exposed  to  the  action  of  the  air  in  the  appa- 
ratus which,  in  connexion  with  the  respiratory 
process,  we  have  denominated  lungs,  gills,  &c., 
another  by  which  it  is  finally  distributed  for 
the  uses  of  the  system.  This  double  circula- 
tion is  accomplished  by  a  great  variety  of  con- 
trivances (vide  articles  HEART  and  CIRCULA- 
TION). In  some  tribes  we  find  more  than  one 
vessel, — two,  or  three,  each  apparently  inde- 
pendent of  the  other,  though  communicating 
together,  which  are  subservient  to  the  distri- 
bution of  the  nutrient  fluid  to  the  different  parts 
of  the  body  of  the  animal. 

The  chief  differences  between  vegetables  and 
animals  with  respect  to  their  circulation,  con- 
sequently, appear  to  be  these :  in  vegetables 
the  motion  of  the  sap  or  aliment  takes  place 
through  the  whole  of  one  of  the  tissues  of 
which  they  consist;  that  of  the  cambium  or 
proper  nutritive  fluid  through  the  whole  of 
another  of  these  tissues,  in  opposite  directions 
simply,  and  by  the  intermedium  of  fascicu- 
lated, very  numerous,  and  independent  vessels  ; 
whereas  the  aliment  of  animals  does  not  cir- 
culate through  their  bodies,  but  the  nutritive 
fluid  prepared  from  it  is  collected  and  con- 
fined within  peculiar  channels,  connected  at 
both  extremities  in  such  wise  as  to  form  a  con- 
tinuous circle.  In  vegetables  we  perceive 
nothing  like  tendency  towards  or  distribution 
from  a  central  reservoir,  nothing  like  ramifica- 
tion from  larger  to  smaller  branches,  &c. ;  con- 
sequently not!) ing  like  a  heart,  as  we  do  in 
animals  above  the  very  lowest.  In  vegetables, 
again,  we  see  nothing  like  the  two-fold  distri- 
bution of  the  nutrient  fluid  within  different 
orders  of  vessels,  the  one  to  the  organs  of 
respiration,  the  other  to  the  system  at  large,  as 
occurs  among  all  animals  possessing  a  some- 
what complicated  organization. 

We  have  recognized  the  heart  as  the  princi- 


pal cause  of  the  motions  performed  by  the  .fluids 
within  the  bodies  of  animals ;  but  as  neither 
all  animals  have  a  heart  and  yet  exhibit  their 
nutrient  fluids  in  motion  ;  indeed,  as  a  distinct 
circulation  of  the  blood  may  be  demonstrated 
in   many  animals,  and   probably  takes   place 
in  all  at  periods   of  their  evolution  anterior 
to  the  existence  of  a  heart ;  and  further,  as 
vegetables  exhibit  a  motion  or  circulation  of 
their  fluids  without  the  agency  of  any  special 
organ,  it  is  necessary  to  acknowledge  a  new 
law  by  virtue  of  which  the  fluids  of  organized 
beings  generally  go  their  round  or  reach  their 
destination.     This  law  has  been  designated  as 
the  propulsive, — a   power  inherent  in  the  nu- 
tritive globules  of  living  beings,  and  one  of 
the  special  laws  superadded  to  the  general  and 
all-pervading  forces  that  regulate  the  universe. 
One  fundamental   distinction  between   the 
bodies  of  the  organic  and  inorganic  kingdoms 
we  have  found  based  upon  the  permanence  of 
the  parts,  the  constancy  of  the  relations,  affi- 
nities, &c.  of  the  component  elements  of  the 
one,  and  the  incessant  changes  or  renewals  and 
decompositions  which  these  parts  or  elements 
undergo  in  the  other.     The  various  processes 
by  which  the  aliment  of  vegetables  and  animals 
is  converted  into  a  succus  proprius,  the  final 
means   of  their   individual   conservation   and 
evolution  we  have  now  examined  ;    we  have 
only  farther  to  discover  this  nutrient  juice  con- 
verted into  the  different  tissues  and  substances 
of  which  organized  beings  consist,  to  have  a 
complete  view  of  the  vital  act  of  nutrition. 
But  here  we  are  compelled  to  pause.     Of  the 
processes  by  which  this  transformation  is  ac- 
complished we  know  next  to  nothing ;  all  we 
are  assured  of  is,  that  each  tissue  and  organ 
seizes  upon  and  converts  into  its  proper  sub- 
stance those  particles  enveloped  in  the  general 
mass  of  circulating  fluids  brought  into  rela- 
tionship with  it,  and  which  are  adapted  to  this 
purpose,  at  the  same  time  that  the  particles 
which  have   already  been   consolidated    and 
served  their  office  are  reduced  to   the   fluid 
state,  absorbed  back   into  the  torrent  of  the 
circulation,   and   afterwards    either   abstracted 
and  thrown  out  of  the  body  by  the  operation 
of  certain  organs  charged  with  this  duty,  or 
being  subjected  to  the  action  of  the  atmos- 
pheric air  in   the  lungs,  gills,  skin,  &c.  are 
restored  to  their  fitness  once  more  to  enter  as 
temporary   constituents   of    the    organization. 
It  is  evident,  therefore,  that  we  are  only  ac- 
quainted   with   this   operation    in   its   effects. 
The  act  of  ultimate  nutrition  has  been  happily 
entitled  one  of  continuous  generation  in  each 
living  being  and  its  parts  ;  it  takes  place  in 
conformity  with  the  laws  of  vitality  instituted, 
and  probably  originating  and  ending  in   living 
organized  beings. 

This  subject,  however  interesting,  we  must 
reluctantly  forsake,  referring  to  the  article  on 
NUTRITION,  and  to  the  consideration  of  what 
has  been  called  the  nisus formations,  or  plastic 
power  in  our  article  on  FCETAL  DEVELOPMENT. 

Vegetables  and  animals,  from  this  review, 
appear  to  differ  little  from  one  another  in  all 


ANIMAL. 


135 


that  regards  their  nutrition.  The  processes  that 
lead  to  this  conclusion  may  be,  and,  indeed, 
are  more  complicated  among  animals  than 
among  vegetables  ;  but  the  essence  of  the  final 
act  is  very  nearly  the  same  in  both.  Neither 
shall  we  be  able  to  demonstrate  any  great 
want  of  uniformity  between  these  different 
classes  of  organized  beings  in  several  of  the 
actions  which  we  shall  next  discuss  ;  in  others, 
however,  we  shall  discover  an  impassable  line 
of  demarcation  between  them.  The  first  of 
these  actions  which  we  shall  consider  is 

Secretion. — \Ve  have  already  had  occasion 
to  mention  the  watery  exhalation  and  oxygen 
thrown  off  by  the  leaves  of  vegetables.  Divers 
other  substances  are  excreted  by  the  same  parts, 
— water,  various  acrid,  glutinous,  saccharine, 
and  balsamic  substances.  It  is  even  by  means 
of  the  leaves  that  vegetables  throw  out.  those 
substances  which  they  may  have  absorbed  by 
their  roots,  and  which  seemed  calculated  to 
injure  them.  We  are  at  no  loss,  moreover,  to 
demonstrate  numerous  apparently  glandular 
organs  in  vegetables  for  the  elaboration  of  a 
variety  of  substances,  many  of  them  very  acrid. 
The  flowers  of  vegetables'  secrete,  in  the  first 
place,  certain  matters,  the  infinite  variety  of 
whose  odours  proclaims  them  to  be  different; 
the  nectaries  are  also  filled  with  fluids,  which 
are  sweet  in  many  tribes.  Lastly,  in  the 
flowers,  the  male  fecundating  matter,  and  the 
fluid  that  moistens  the  pistillum  are  secreted. 
Nor  are  vegetables  without  internal  secretions, 
among  the  number  of  which  certain  aeriform 
fluids  are  not  the  least  curious.  The  other 
secretions  of  vegetables  are  of  infinite  variety, 
— gummy,  oleaginous,  balsamic,  camphoric, 
&c.  &c.  These  are  all  stored  up  in  cells  con- 
tained in  different  parts  ^f  each  individual 
plant,  and  undoubtedly  either  subserve  im- 
portant purposes  in  their  several  economies, 
with  the  nature  of  which  we  are  very  imper- 
fectly acquainted,  or  are  in  relation  with  some 
other  system  in  the  universe,  affording  food  to 
numerous  tribes  of  insects,  or  materials  which 
stand  in  relation  to  animals  and  man  as  means 
of  accomplishing  a  variety  of  ends,  the  impulses 
to  which  they  bring  into  the  world  with  them, 
though  they  are  launched  upon  existence  un- 
furnished with  the  materials. 

We  have  also  hinted  at  the  watery  and 
gazeous  products  of  the  respiration  of  animals, 
and  consideration  for  a  moment  enables  us 
to  make  a  long  catalogue  of  other  secretions 
both  with  reference  to  individuals  arid  to 
species.  We  have,  for  instance,  the  limpid 
fluids  that  bedew  the  cellular  and  serous  mem- 
branes, serum  and  synovia,  and  fill  various 
cavities  in  the  body — the  chambers  of  the 
ear  and  of  the  eye  particularly  ;  those  that 
moisten  and  defend  the  surfaces  of  the  mucous 
membranes,  the  tears  and  mucus ;  those  that 
are  subservient  to  digestion,  the  saliva,  gastric 
juice,  pancreatic  juice,  and  bile";  those  that 
lubricate  and  prevent  the  surfaces  exposed  to 
the  air  from  drying,  the  sebaceous  or  oleaginous 
fluids  of  the  skin,  and  cerumen  of  the  ears  ; 
those  that  are  laid  up  as  reservoirs  of  nutriment 


or  defences  from  the  cold,  the  fat,  marrow,  &c.; 
those  that  are  the  vehicles  for  the  worn-out 
particles  of  the  body,  the  urine  and  perspira- 
tion ;  those  that  minister  to  the  reproduction 
of  the  species,  the  fluids  of  the  female  germ 
or  ovum,  the  spermatic  and   prostatic   fluids 
of  the  male  ;  and  finally,  those  that  are  poured 
out  among  the  mammalia  as  the  first  aliment 
for  the  newly-born  being,  the  milk.     Nor  is 
the  list   exhausted,   for   numerous   specie*  of 
animals  have  peculiar  fluids  which  are  useful 
to  them  in  the  places  they  hold  in  the  svstem 
of  creation ;  among   these   are  the  venomous 
fluids  of  serpents,  and  of  the  stings  of  numerous 
insects,  the  inky  fluid  of  the  cuttle  fish,  the 
fetid  fluids  of  the  anal  glands  of  the  carnivora, 
rodentia,  &c. ;   the  fluid   with   which    spiders 
weave  their  web ;    the   wax  with  which   bees 
build  their  cells,  &.c.     Secretion  is,  therefore, 
a  much  more  extensive  function  among  animals 
than  among  vegetables ;  the  products  are  still 
more  various,  and  the  apparatus  by  which  they 
are  eliminated  is,  generally  speaking,  far  more 
complicated   among  the   former  than    among 
the  latter.     Certainly,  in  the  very  lowest  tribes 
of  animals,  secretion  is  an  exceedingly  simple 
process  contrasted  with  what  it  becomes  in  the 
higher,  whose  organization  is  more  complex. 
Among    the    polypi,    medusa?,    and   entozoa, 
the  whole  of  this  function  seems  to  consist  in 
a  kind  of  transudation,  or  exhalation  from  the 
surface  of  their  homogeneous  bodies,  without 
the  intermedium  of  any  special  organ.    Among 
animals  higher  in  the  scale  we  find  secretion 
performed   in  two   modes, — by  vessels,  when 
the  act  is  entitled  exhalation,  and  by  means 
of  certain   special    organs   named   glands,  an 
arrangement  which  \ve  also  find  among  vege- 
tables.    The  skin  and  pulmonary  surface  are 
the   great   implements    of   exhalation    among 
animals,  as  the  leaves  are  among  vegetables ; 
almost  all  the  rest  of  the  secretions  take  place 
by  the  instrumentality  of  glands. 

In  vegetables  secretion  seems  to  be  limited 
to  the  preparation  of  the  nutrient  fluid  by  the 
elimination  of  certain  matters,  and,  so  far  as 
our  knowledge  extends  of  the  end  to  be  an- 
swered by  any  act,  for  the  formation  of  the 
generative  fluids;  we  do  not,  in  fact,  find 
among  vegetables  any  apparatus  set  apart  for 
the  excretion  of  matters  derived  from  a  change 
in  the  constituent  particles  of  the  organs  once 
formed.  Among  animals,  again,  the  apparatus 
by  which  this  depuration  of  the  system  is  ac- 
complished is  one  of  the  most  important  of  all 
to  the  preservation  of  the  individual.  Secretion 
among  vegetables  is  a  function  much  more 
under  the  influence  of  external  circumstances 
than  it  is  among  animals  ;  it  is  also  more  sub- 
ject to  periodical  changes  among  the  former 
than  among  the  latter,  and  whilst  the  function 
is  mostly  called  into  activity  by  the  stimulus  of 
light,  heat,  &c.  in  the  one,  it  rather  obeys  cer- 
tain internal  and  peculiar  stimuli  transmitted 
through  the  medium  of  the  nervous  system  in 
the  other. 

Like  all  the  other  special  modes  of  activity 
manifested  by  organized  beings,  secretion  is 


136 


ANIMAL. 


one  of  the  products  of  the  laws  of  vitality  with 
the  essence  of  which  we  are  altogether  un- 
acquainted. 

Besides  the  secretion  of  the  various  gaseous, 
fluid  and  solid  matters  mentioned,  vegetables 
and  animals  appear  in  common  to  possess  the 
power  of  disengaging  certain  imponderable 
elements — heat,  light,  and  electricity. 

Heat. — There  has  been  considerable  variety 
of  opinion  among  physiologists  with  regard  to 
the  extent  to  which  vegetables  have  the  power 
of  maintaining  a  temperature  of  their  own  inde- 
pendently of  that  of  the  surrounding  media. 
Nor  is  this  question,  in  our  opinion,  yet  com- 
pletely set  at  rest.  It  is  certain  that  trees  in 
high  northern  latitudes  endure  a  cold  many  de- 
grees below  zero  without  injury,  whilst  in  in- 
tertropical  countries  they  are  frequently  ex- 
posed even  in  the  shade  to  a  heat  above  that 
of  any  animal  without  perishing;  actual  ex- 
periment, indeed,  proves  that  they  preserve  a 
temperature  intermediate  between  that  of  the 
extreme  heat  and  extreme  cold  of  the  diurnal 
variations  of  those  latitudes  in  which  they  are 
indigenous.  This  circumstance  is  explained 
variously,  some  attributing  it  to  a  vital  property 
in  plants  to  regulate  to  a  certain  extent  their 
own  temperature,  others  alleging  that  it  is 
merely  owing  to  the  indifferent  conducting 
qualities  of  the  materials  of  which  vegetables 
are  composed.  The  thermometer  has  been  seen 
several  degrees  below  the  freezing  point  of 
water  within  the  trunks  of  fir  trees,  without 
their  vitality  being  affected ;  but  it  is  probable 
that  the  constitution  of  this  tribe  renders  them 
capable  of  enduring  such  a  reduction  of  tem- 
perature with  impunity  as  would  prove  fatal  to 
other  trees  with  simple  watery  sap. 

On  the  other  hand,  it  is  quite  certain  that  the 
flowers  of  many  vegetables  have  the  power  of 
disengaging  heat,  a  difference  of  ten,  twenty, 
and  even  more  than  thirty  degrees  having  been 
observed  at  sun-rise  between  the  temperature 
of  the  atmosphere  and  that  of  the  flowers  of 
different  vegetables  in  southern  latitudes,  and 
the  same  thing  is  known  to  occur,  though  to  a 
less  extent,  in  northern  countries. 

It  would  therefore  be  unfair,  with  such  facts 
before  us,  to  deny  altogether  to  vegetables  the 
faculty  of  disengaging  caloric.  Arguments,  in- 
deed, a  priori,  might  be  adduced  to  show  that 
they  must  almost  necessarily  possess  such  a 
property :  they  are  the  subjects  of  incessant 
change ;  and  one  of  the  most  universal  of  the 
physical  laws  involves  a  change  of  temperature 
on  any  change  of  constitution. 

If  the  faculty  of  vegetables  generally  to 
secrete  or  eliminate  caloric  be  doubtful,  how- 
ever, it  is  indisputable  that  among  all  animals 
a  little  raised  above  those  at  the  very  bottom  of 
the  scale,  there  is  an  inherent  power  of  gene- 
rating caloric,  which  in  their  state  of  maturity 
is  nearly  determinate  as  regards  each  particular 
species.'  Mammalia  and  birds  have  universally 
the  highest  temperatures. 

Reptiles  or  cold-blooded  animals,  as  they 
are  improperly  called,  have  also  the  power  of 


engendering  heat,  and  of  regulating  their  own 
temperature :  this  faculty,  however,  and  the 
degree  of  heat  they  possess  at  different  times, 
are  influenced  to  a  very  considerable  degree  by 
the  heat  of  the  media  in  which  they  live.  The 
same  statements  may  be  made  with  regard  to 
fishes.  The  temperature  of  these  creatures  is 
generally  several  degrees  above  that  of  the  water 
they  inhabit;  but  it  also  varies  with  the  tem- 
perature of  their  native  element. 

Many  insects  have  a  very  decided  power  of 
engendering  heat  and  of  regulating  their  tem- 
perature ;  and  similar  faculties  have  been  de- 
monstrated in  the  Crustacea,  the  mollusca,  and 
the  annelida.  These  tribes,  however,  are  all 
very  much  influenced  by  the  temperature  of  the 
media  surrounded  by  which  they  live. 

No  great  difference  is  therefore  discernible 
between  vegetables  and  animals  in  the  faculties 
they  possess  of  engendering  caloric  and  regu- 
lating their  own  temperature;  the  faculty  is 
only  much  more  decided,  and  possessed  to  a 
far  greater  extent  among  the  more  perfect 
classes  of  animals  generally  than  among  vege- 
tables at  large.  It  may  very  fairly,  in  the 
present  state  of  our  knowledge,  be  ascribed  as 
a  common  property. 

As  to  the  mode  in  which  heat  is  engendered, 
opinions  are  still  very  much  divided.  The 
chemical  and  mechanical  explanations  that 
have  been  given  of  the  phenomenon  are  not 
universally  applicable.  All  we  can  say  at  the 
present  day  is  that  the  production  of  heat  and 
the  power  of  regulating  their  temperature  pos- 
sessed by  organized  beings  is  another  of  the 
hidden  and  singular  laws  or  properties  intro- 
duced into  the  system  of  the  universe  with  their 
creation. 

Light. — Many  unorganized  bodies  have  the 
property  of  shining  or  giving  out  light  for  some 
time  after  they  have  been  exposed  to  the  bright 
rays  of  the  sun,  or  have  been  heated  in  the  fire, 
or  when  they  are  struck  together  or  smartly 
compressed,  and  this  certainly  without  any 
decomposition  of  their  substance.  The  disen- 
gagement of  light,  again,  is  a  very  uniform 
accompaniment  of  the  decomposition  and  com- 
position of  inorganic  substances,  and  it  appears 
to  be  a  very  constant  attendant  upon  electrical 
phenomena. 

Various  organic  substances  and  products  of 
organization  have  a  similar  property;  living 
vegetables,  too,  particularly  the  flowers,  have 
been  seen  to  give  out  light  by  authorities  so 
respectable,  that  though  the  fact  has  been 
called  in  question  by  others  of  great  name, 
there  seems  no  sufficient  reason  for  treating  all 
that  has  been  said  on  the  subject  as  illusion  : 
in  the  physical  sciences  negatives  cannot  be 
received  as  evidence  of  equal  value  with  posi- 
tives. 

No  one  thinks  of  calling  in  question  the 
luminousness  of  animals ;  most  of  the  innu- 
merable inferior  tribes  that  live  in  the  sea, 
appear  to  possess  and  to  manifest  this  pro- 
perty at  different  seasons.  The  luminous- 
ness  of  the  ocean  itself,  so  familiarly  known, 
seems  to  depend  on  the  presence  of  multitudes 


ANIMAL. 


137 


of  infusory  animals  within  its  bosom.  Many 
tribes  of  insects  shine  in  the  dark.  The  phe- 
nomenon is  not  certainly  known  to  be  mani- 
fested by  any  of  the  class  of  reptiles,  birds,  or 
mammalia.  It  appears  to  depend,  in  insects 
particularly,  on  the  presence  of  a  peculiar 
matter,  secreted  by  their  bodies  and  stored  up 
in  particular  points,  which,  under  the  influence 
of  a  temperature  elevated  in  a  certain  degree, 
and  the  contact  of  atmospheric  air,  enters  into 
a  kind  of  combustion  during  which  light  is 
emitted.  Is  the  phenomenon  dependent  on 
one  common  cause  in  both  vegetables  and 
animals,  supposing  that  it  does  really  occur 
among  the  former? 

Electrical  phenomena  are  extensively  ex- 
hibited by  the  objects  composing  the  unor- 
ganized'-and  the  organized  world.  In  fact, 
wherever  there  is  composition  and  decompo- 
sition going  on,  there  are  electrical  phenomena 
manifested.  The  action  of  the  immense  mass 
of  vegetables  on  the  air,  the  evolution  of  oxygen 
in  the  sunshine,  and  the  formation  of  carbonic 
acid  during  the  dark,  has  even  been  supposed 
by  an  ingenious  natural  philosopher  of  France 
(Pouillet)  to  be  the  principal  source  of  the 
electricity  of  the  atmosphere. 

Galvanic  electricity  is  excited  by  the  contact 
of  the  different  parts  of  which  animal  bodies 
consist,  particularly  of  the  nerves  and  muscular 
flesh;  the  nerve  of  a  frog's  thigh  exposed  and 
isolated,  touched  with  a  piece  of  quivering 
flesh  from  the  body  of  a  bullock  just  slain,  also 
isolated,  causes  the  muscles  to  which  the  nerve 
is  distributed  to  contract  energetically  (Hum- 
boldt).  The  same  phenomenon  occurs  when 
different  other  parts  and  fluids,  particularly  the 
blood,  are  used  to  form  a  chain.  But  the 
electrical  phenomena  manifested  by  animals  at 
large,  are  weak  when  contrasted  with  those 
exhibited  by  certain  fishes  provided  with  spe- 
cial voltaic  piles  or  galvanic  batteries  by  which 
they  give  at  will,  but  not  otherwise,  electrical 
shocks  of  such  violence  as  to  stun  larger  ani- 
mals and  even  to  deprive  smaller  ones  of  life. 
This  electricity  of  animals  must  be  held  as  a 
vital  phenomenon ;  several  of  them  have  in- 
deed a  peculiar  apparatus  for  the  preparation 
of  the  shock,  to  speak  of  the  phenomenon  by 
its  effects,  in  our  ignorance  of  its  essence  or 
efficient  cause,  but  this  loses  its  power  when 
the  nerves  that  are  abundantly  distributed  to  it 
are  divided. 

Electrical  phenomena  are  not  so  obviously 
displayed  by  any  other  tribe  of  animals  as  by 
fishes ;  but  it  has  been  rendered  next  to  certain 
that  muscular  contractions  are  uniformly  accom- 
panied by  a  kind  of  electrical  discharge  from 
the  nervous  fibrils  distributed  to  the  special  or- 
gans of  voluntary  motion. 

Animals,  from  this  brief  review,  appear  to  pos- 
sess electrical  capacities  in  a  much  higher  de- 
gree than  vegetables,  in  which  the  phenomenon 
is  even  explicable  on  ordinary  chemical  prin- 
ciples, whilst  among  animals  it  is  unquestion- 
ably one  of  the  effects  of  vitality. 

We  have  already  indicated  the  existence  of 
two  faculties  among  animals  which  become 


necessary  or  complemental  to  them  as  agents 
entrusted  with  their  preservation  as  individuals, 
and  their  continuation  as  kinds;  these  are 
voluntary  motion  and  sensation.  But  motion 
in  the  abstract  is  a  phenomenon  of  much  more 
extensive  occurrence  among  organized  beings 
than  the  notion  we  form  of  the  act  as  connected 
with  the  existence  of  a  muscular  system.  Mo- 
tion is  in  fact  a  quality  inherent  in  organized 
beings ;  they  cannot  be  conceived  as  existing 
without  change,  and  change  implies  motion. 
In  most,  or  indeed  in  the  whole  of  the  actions 
which  we  have  glanced  at  as  manifested  by 
them,  we  have  supposed  motion.  The  simplest 
of  all  animals,  the  infusoria,  move  about  in 
many  cases  with  great  briskness;  the  polypes, 
composed  of  an  uniform  gelatinous  mass,  also 
move  in  various  directions ;  the  acalephs,  with 
a  similar  structure,  rise  from  the  bottom  and 
propel  themselves  through  the  waters  of  the 
ocean  by  a  succession  of  contractions  of  their 
disc,  of  their  tentacula,  or  of  the  fringe-like 
or  foliaceous  bodies  with  which  several  orders 
of  the  genus  are  provided.  Many  of  the  en- 
tozoa  too,  whose  bodies  consist  of  a  simple 
gelatinous  or  mucous  tissue,  execute  motions  in 
various  senses. 

But  it  is  not  only  as  a  whole  that  a  body 
endowed  with  life  and  organization  possesses  a 
capacity  of  motion.  Many  of  its  parts,  and 
particularly  the  globules  which  enter  as  essen- 
tial and  integral  parts  of  the  fluids  contained 
in  organized  bodies,  have  inherent  powers  of 
motion;  the  globules  of  the  blood,  for  instance, 
those  of  the  spermatic  fluid,  and  perhaps  also 
the  germ  included  within  the  ova  of  the  polype, 
mollusc,  &c.,  have  all  been  observed  in  motion, 
and  the  means  by  which  it  is  accomplished 
even  demonstrated  in  many  cases.  But  there 
is  nothing  absolutely  peculiar  in  such  indivi- 
dual instances,  for  we  must  need  conceive 
motion  in  the  first  constituent  elements  of  all 
organisms  without  exception,  long  before  a 
muscular,  a  cellular,  a  nervous,  or  any  other 
distinct  system  has  existence.* 

Motion  of  all  kinds,  therefore,  automatic  as 
well  as  that  which  is  voluntary,  must  be  held 
as  a  quality  inherent  in  organized  or  living 
beings.  The  cause  of  this  phenomenon,  as  of 
so  many  others  manifested  in  the  world  of  or- 
ganization, has  been  the  subject  of  much  dif- 
ference of  opinion  and  of  much  dispute  among 
physiologists,  and  many  titles  have  been  ima- 
gined by  which  the  agent  or  primary  cause  of 
the  act  has  been  sought  to  be  designated,  or 
the  act  itself  to  be  explained. 

It  is  quite  certain  that  the  capacity  to  com- 
mence and  to  continue  the  phenomena  which 
we  designate  as  vital,  or  the  motions  which 
constitute  these  phenomena,  depends  first  on 
a  variety  of  external  conditions,  such  as  a 

*  Such  motion  is  indubitable.  The  organic  glo- 
bule has  capacities  of  motion  inherent  in  itself, 
different  from  the  motions  of  unorganized  objects 
in  a  state  of  extreme  division,  as  is  proved  by  the 
motions  of  each  kind  of  body  being  different,  and 
those  of  organized  globules  being  interrupted  by  the 
electric  spark,  or  whatever  destroys  their  vitality 
—  acids,  alkalis,  poisons,  &c. 


138 


ANIMAL. 


certain  temperature,  intercourse  with  the  air 
of  the  atmosphere,  supplies  of  aliment,  and 
the  access  of  light,  and  it  is  indubitable  that 
organized  beings  exhibit  phenomena  that 
may  be  designated  excitability,  irritability, 
vital  force,  &c.,  which  are  only  other  names 
for  these  manifestations ;  but  it  is  also  certain 
that  external  conditions  are  of  themselves  ina- 
dequate to  originate  manifestations  of  vitality, 
and  that  the  phenomena  of  living  organized 
beings,  generally  designated  excitability,  irrita- 
bility, incitability,  &c.,  are  consequences  of  a 
state  of  things  to  explain  which  they  have  been 
conceived  as  causes,  under  the  title  of  life, 
vital  principle,  soul,  &c.  The  term  excitability 
should  be  used  in  physiology,  in  the  very 
widest  sense,  to  signify  a  property  inherent  in 
organized  matter  generally,  to  be  determined 
to  manifestations  of  activity  under  and  in  con- 
formity with  external  influences  (Tiedemann). 
\Ve  in  fact  see  organized  matter  of  every  de- 
scription— the  green  matter  of  Priestley,  con- 
fervae,  infusory  animals,  &c.,  acquiring  organic 
forms  under  the  dominion  of  outward  influences, 
and  every  species  of  organized  being  existing 
within  a  determinate  circle  of  external  agency. 

It  were  a  grave  mistake  to  suppose  this 
agency  either  chemical  or  mechanical  in  its  na- 
ture ;  when  of  such  potency  as  to  act  either 
chemically  or  mechanically  it  is  destructive 
instead  of  productive  of  vital  phenomena. 
These  phenomena,  therefore,  and  external 
influences  are  rather  in  opposition  to  one 
another  than  identical.  External  influences  ex- 
cite organized  beings  to  manifest  their  inherent 
capacities;  they  do  not  bestow  these  capacities ; 
all  organized  beings,  indeed,  and  each  parti- 
cular tissue  of  every  individual  among  them, 
are  excited  in  different  modes  by  the  various 
influences  from  without ;  the  stimulus  is  iden- 
tical, the  effects  are  infinitely  different. 

But  organized  beings,  and  especially  ani- 
mals, are  not  dependent  on  external  influences 
alone  for  the  manifestation  of  their  peculiar 
properties;  they  have  themselves  the  additional 
power  of  engendering  stimuli  proper  to  arouse 
into  activity  the  various  organs  and  systems  of 
which  they  are  composed.  The  fluids  circu- 
lating through  every  part  of  their  bodies  may 
be  regarded  in  the  light  of  the  most  generally 
distributed  stimuli  of  this  description.  The 
nrevous  system  is  another  and  important  source 
of  excitation,  the  influence  of  which  is  felt  in 
every  part  of  the  organism  of  all  animals  above 
the  very  lowest.  The  various  instincts,  appe- 
tites, propensities,  sentiments,  and  intellectual 
faculties,  also,  which  all  emanate  from  the 
nervous  system,  are  inherent  causes  of  a  vast 
variety  of  manifestations  of  activity  among  the 
more  perfect  animals.  There  are  yet  other 
stimuli  of  a  mechanical,  or  chemical,  or  pecu- 
culiar  nature,  which  excite  unusual  or  ano- 
malous manifestations ;  in  this  category  may 
be  placed  contagions  of  different  kinds,  the 
causes  of  epidemic  diseases,  medicines,  &c. 

With  regard  to  the  essence  or  cause  of  this 
property  of  the  organic  globule  to  commence, 
and  of  the  perfectly  developed  organism  to 
manifest  the  various  phenomena  whose  sum 


constitutes  their  vitality,  and  endows  them 
with  their  various  cognizable  properties,  all  we 
can  say  is  that  it  appears  to  inhere  immedi- 
ately in  the  particular  state  of  matter  which 
composes  them.  What  this  state  is  in  itself 
we  cannot  tell ;  but  we  are  familiar  with  the 
phenomena  which  ensue  from,  and  which  in- 
deed reveal  to  us  its  existence.  It  is  evidently 
as  diversified  as  species,  and  as  the  systems  or 
organs  possessed  by  the  individuals  severally 
composing  these :  there  is  a  power — the  nisus 
formations,  the  vis  plastica,  in  the  matter  sus- 
ceptible of  formation, — the  organic  globule,  the 
germ, — which  presides  over  and  regulates  its 
acts;  and  there  are  powers  inherent  in  the  parts 
or  organisms  to  which  the  plastic  force  gives 
rise,  in  accordance  with  which  they  manifest 
the  special  acts  that  distinguish  them.  It 
would  be  improper,  however,  to  regard  this 
power  or  these  powers  as  forces  apart  from 
and  other  than  the  globules,  germs  or  organisms 
themselves ;  in  the  present  state  of  our  know- 
ledge we  cannot  separate  exciting  causes  from 
manifestations  of  activity;  all  we  can  venture 
to  say  is  that  germs  exist,  that  organisms  exist 
with  inherent  capacities  of  action  in  harmony 
with  the  peculiar  states  of  their  constituent 
elements,  thus :  the  germ  of  the  infusory  ani- 
mal exists  with  its  inherent  capacity  to  en- 
gender an  infusory  animal,  the  germ  of  the 
polype  with  its  inherent  power  to  produce  a 
polype;  in  the  same  way  the  various  tissues, 
vessels,  glands,  &c.  of  vegetables  and  animals 
exist  with  their  special  capacities  of  excitation, 
which  are  manifested  in  the  particular  functions 
they  severally  perform.  Excitability  is  there- 
fore a  multiform  property  and  a  consequence, 
not  a  single  peculiar  power  inherent  in  orga- 
nized beings,  the  fundamental  cause  of  their 
actions  and  identical  with  or  itself  the  living 
principle.  Dependent  on  the  integrity  and 
continuance  of  the  functions  of  nutrition,  how 
can  it  be  the  cause  of  these?  Only  manifested 
in  kind,  with  the  occurrence  of  specific  organs, 
how  can  it  be  the  cause  of  their  several  ma- 
nifestations ? 

We  are  altogether  in  the  dark  with  regard 
to  the  mode  in  which  the  motions  and  other 
actions  of  organized  beings  are  performed,  how 
or  by  what  law  the  globule  that  in  the  infusion 
of  organic  matter  is  to  become  an  infusory 
animal  moves,  as  well  as  of  the  manner  in 
which  the  contractility  of  a  muscle  is  excited 
by  the  stimuli  fitted  to  call  this  quality  into 
action.  The  contractility  of  the  infusoria,  po- 
lypi, medusae,  and  other  similar  tribes  appears 
to  be  peculiar.  The  motions  exhibited  by  the 
confervae,  tremellae,  and  simplest  vegetables 
are  also  peculiar  to  them,  they  differ  from 
those  manifested  by  the  simplest  animals  in 
being  entirely  under  the  influence  of  external 
influences,  and  showing  nothing  like  spon- 
taneity. The  tissues  of  all  animals,  even  the 
most  complicated,  show  traces  of  a  vital  ten- 
sion or  contractility,  different  from  simple 
elasticity  and  not  depending  on  muscularity; 
the  cellular  membrane,  skin,  fibrous  tissues 
generally,  excretory  ducts,  and  vessels  of  all 
descriptions  tend  to  contract  upon  the  parts 


ANIMAL. 


139 


and  fluids  they  surround  and  include.  This 
tonicity  or  peculiar  contractility  disappears 
in  great  part  with  the  cessation  of  life :  a 
wound  made  in  a  dead  body  never  trapes  as 
it  does  in  a  living  one.  Something  of  the 
same  kind  exists  in  vegetables ;  the  sap  as- 
cends with  greatly  increased  velocity  in  the 
young  shoots  under  the  influence  of  stimuli  of 
different  kinds,  and  its  flow  is  checked  by  nar- 
cotics and  altogether  arrested  by  poisons ;  it  is 
probable,  therefore,  that  it  takes  place  in  con- 
sequence of  a  vital  tonicity  or  contractility  in 
the  sides  of  the  sap- vessels  which  contain  it. 


within,  and  of  the  phenomena  that  occur 
without  them.  Even  this  distinction,  how- 
ever, is  only  applicable  as  regards  species  con- 
siderably raised  above  the  lowest ;  would  we 
indicate  the  differences  between  the  most  in- 
ferior members  of  either  series  we  must  con 
descend  upon  particulars,  and,  in  some  in- 
stances, even  call  in  analogy  and  inference  to 
our  aid  in  laying  down  the  chart  of  their  re- 
semblances and  dissimilarities. 


From   this   general   review  of  the   physical 
construction  and  vital  phenomena  of  the  two 
grand  classes  of  organized  beings,  vegetables 
and  animals,  it  is  impossible  not  to  remark  the 
strong   features  of  resemblance,   and   yet   the 
numerous   points   of   difference  they  exhibit. 
Both  have  a  beginning,  which  happens  very 
much  in  the  same  way  in  each ;  both  live  as 
individuals  by  the  susception  of  aliment  and 
its  prepration  by  a  variety  of  processes,  which, 
in   their  essence,  differ  but  little  from  one  an- 
other ;  both  continue  themselves  as  kinds  in  a 
surprisingly  similar  manner ;  both  exhibit  the 
changes  denominated  age ;  both  have  a  merely 
temporary  existence,  consequently  both  exhibit 
the  phenomenon  entitled  death,  and  both  are 
decompounded  after  the  cessation  of  life,  their 
constituent  elements  assuming  new  shapes,  in 
obedience   to    the   general    laws   of   chemical 
affinity,  which  had  been  set  at  nought  during 
the  existence  of  the  individuals  in  either  class. 
Notwithstanding  these  striking  points  of  re- 
semblance between  vegetables  and  animals  in 
all  that  is  essential  or  general,  it  is  impossible, 
as  we  have   seen,  to   condescend   upon    par- 
ticulars without  immediately  detecting  differ- 
ences  that   distinguish   in    the   most    marked 
manner  the  individuals  of  the  one  class  from 
those  of  the  other.     It  is  always  in  their  lowest 
or   most   simple  species   that  we  remark  the 
most    striking    similarity   between   vegetables 
and  animals,  and  it  is  among  these  that  we 
constantly  find   ourselves  most  at  a   loss   for 
characters  distinctive  of  each.     We  observe  no 
evidence  of  anything  like  a  connected  chain 
of  being  from  the  lowest  or  most  simple,  to 
the  highest  or  most  complicated  vegetable,  and 
from   this   through   the   most   inferior  animal 
upwards  to  man  ;  it  is,  on  the  contrary,  in  the 
extremes   or  lowest  grades   of  each  that  the 
greatest   similarity  prevails ;    here   vegetables 
and   animals   approximate  very  closely,   here 
they  literally  inosculate,  but  from  this  common 
point  they  begin  to  form  two   distinct  series, 
which    diverge   ever   more    and  more   widely 
from  one  another  as  they  ascend.     Without 
attention  to  particulars,  it  would  seem  impos- 
sible to  adduce  as  ultimate  terms  of  distinction 
between  vegetables  and  animals,  other  faculties 
than  those  of  voluntary  motion  and  sensation 
as  peculiar  to  the  latter,  in  virtue  of  the  one  of 
which  powers  they  are  rendered  in  a  great  mea- 
sure masters  of  their  own  existence,  whilst  by  the 
other  they  are  endowed  with  consciousness  of 
many   of    the   various   acts    that    take    place 


COMPARISON  OF  ANIMALS  WITH  ONE  ANOTHER. 

This  head  is  also  comprised  within  that  of 
our  enti>e  Cyclopaedia.  The  glance  we  shall 
cast  over  the  field  it  embraces  will,  therefore, 
be  very  cursory,  and  the  views  taken  of  the 
objects  it  presents  extremely  general. 

JPkysicut  qualities  and  material  constitution 
of  annuals — In  point  of  size,  animals  differ 
most  widely  from  one  another.  The  existence 
of  some  is  only  made  known  by  the  aid  of  a 
powerful  microscope,  the  length  of  others  ex- 
ceeds a  hundred  feet,  and  their  weight  amounts 
to  many  tons.  These  extremes  include  animals 
of  every  intermediate  bulk. 

Tbejorm  assumed  by  animals  presents  many 
more  interesting  particulars  for  study  and  in- 
vestigation than  the  mere  bulk  of  their  bodies. 
The  consideration  of  this  accident  has  even 
been  made  the  ground  of  a  classification  of  the 
objects  included  within  the  animal  kingdom 
by  several  naturalists,  and  although  not  adopted 
as  the  sole  basis  of  any  one  now  generally 
received,  it  nevertheless  furnishes  the  element 
upon  which  several  of  the  classes  even  of  the 
most  recent  are  established.  Some  animals 
present  themselves  in  the  likeness  of  a  globule, 
others  of  a  filament,  and  others  of  a  small 
fattened  membrane  (the  cyclides).  Various 
animals,  again,  from  exhibiting  no  uniform  or 
regular  shape,  have  been  entitled  amorphous  or 
heteramorphous . 

Animals  which  exhibit  a  determinate  form 
naturally  arrange  themselves  into  two  classes ; 
their  bodies    are    either    disposed    around    a 
centre,  or  they  consist  of  two  similar  halves 
cohering  along  a  middle  plane  or  axis;    the 
first  are  the   radiata,  the  second  the  bin  aria 
or  symmetrica  of  naturalists.     The  radiata  are 
not  a  very  extensive  class  of  animals,  neither  is 
their  organization  extremely  complicated.    The 
symmetrical  is  a  much  more  numerous  class 
than  the  radiated,  and  includes  within  its  limits 
creatures  of  such  simple  structure  as  the  en- 
tozoa,  and  of  such  complicated  fabric  as  quad- 
rupeds and  man.     Of  the  symmetrical  animals, 
some  consist  of  a  mere  trunk  without  appen- 
dices or  limbs ;  those  that  are  provided  with 
limbs,  again,  have  them  in  the  shape  of  feet, 
fins,  wings,  or  hands,  according  to  the  media 
in  which  they  live.     In  some  the  body  forms 
as  it  were  a  single  piece,  in  others  it  is  divided 
into  portions,  such  as  head,  trunk,  and  tail. 
Sometimes  it  is  naked ;  at  others  it  is  covered 
with   shells,  scales,  spines,  hair,  &c.     Some- 
times the  general  integument  is   continuous, 
unpierced  by  any  opening  that  leads  to  the 
interior,  at  others  it  is  reflected  inwards,  and 
lines  extensive  cavities  there  contained. 


140 


ANIMAL. 


With  regard  to  structure,  as  may  be  imagined, 
the  amorphous  tribes,  at  the  bottom  of  the 
scale,  are  the  most  simple  of  all.  The  bodies 
of  some  of  these  are  without  any  internal 
cavity,  and  without  any  division  of  parts; 
they  are  homogeneous  masses,  generally  gela- 
tinous in  appearance,  and  simply  cellular  in 
structure,  without  arrangement  into  tissues  or 
particular  organs.  The  external  surface  of 
these  animals  imbibes  the  matters  which  are 
fitted  to  subserve  the  purposes  of  nutrition, 
and  we  may  presume  that  it  throws  off  by 
transpiration  such  particles  as  are  worn  out 
or  have  accomplished  this  end.  The  external 
surface  is  also  the  organ  of  respiration  in  these 
animals.  They  procreate  by  the  evolution  of 
gemmi  from  their  surface,  and  if  they  possess 
sensibility  the  element  to  which  it  is  attached 
must  be  generally  diffused  throughout  their  sub- 
stance. 

The  organization  of  the  radiata  becomes  con- 
siderably more  complicated.  Fluids  are  no 
longer  absorbed  from  the  external  surface  of 
the  body ;  we  meet  with  an  internal  cavity,  the 
rudiment  of  a  digestive  apparatus,  having  a 
single  opening  in  some  of  the  species,  which 
serves  consequently  for  both  mouth  and  anus, 
but  in  others  presenting  two  openings,  a  mouth 
properly  so  called  on  one  side  of  the  body,  and 
an  anus  on  the  other.  Through  the  walls  of 
this  cavity  the  nutritive  fluids  make  their  way, 
and  infiltrate  the  general  mass  of  the  animal's 
body.  In  this  class  we  also  discover  the 
rudiments  of  a  nervous  and  of  a  muscular  sys- 
tem. The  nervous  system  consists  of  rounded 
masses  of  a  soft  whitish  substance,  equal  in 
number  to  that  of  the  radii  composing  the 
animal,  connected  together  by  slender  white 
cords,  and  sending  off  filaments  of  the  same 
description  to  all  parts  of  the  body,  but  espe- 
cially to  the  outer  integument,  and  to  the  inter- 
nal digestive  apparatus.  The  muscular  system 
consists  of  reddish  and  whitish  fasciculated 
fibres  disposed  in  the  line  of  the  motions.  The 
external  surface  of  these  animals  is  still  the  only 
organ  of  respiration  they  possess. 

The  three  systems  now  enumerated — the 
digestive,  the  nervous,  and  the  muscular — are 
readily  demonstrated  in  the  majority  of  the 
symmetrical  animals,  and  are  even  very  soon 
found  to  have  acquired  complication,  and  to 
have  sundry  other  parts  and  organs  superadded 
to  them.  The  digestive  apparatus  consists  of 
a  mouth  for  the  susception  of  aliment,  of  a 
stomach  for  its  elaboration,  of  an  intestinal 
canal  from  which  the  nutrient  juices  are  ab- 
sorbed, and  of  an  anus  from  which  the  un- 
digested residue  is  expelled.  Whilst  in  the 
radiata  the  nutritious  fluids  passed  through  the 
parietes  of  the  digestive  cavity  to  impregnate 
the  body  of  the  animal,  and  be  assimilated 
with  its  substance  ;  in  the  binaria  we  find 
vessels,  the  rudiments  of  a  circulating  system, 
employed  in  receiving  the  juices  prepared  in 
the  digestive  apparatus  and  transmitting  these 
to  all  parts  of  the  body.  Digestion,  too,  in  this 
class  becomes  a  more  complicated  process  than 
in  the  radiata,  and  various  secreted  fluids, 
saliva  and  particularly  bile,  the  special  products 


of  large  and  evidently  important  organs,  arc 
added  to  the  alimentary  mass  in  its  progress 
through  the  intestinal  canal. 

In  addition  to  the  digestive  apparatus  and 
general  exteinal  respiratory  surface  we  by-and- 
by  find  an  especial  system  dedicated  to  the 
aeration  of  the  juices  prepared  for  nutrition; 
this  is  the  respiratory  apparatus.  Of  extreme 
simplicity  in  the  first  instance,  being  little 
or  no  more  than  a  fold  of  integument  turned 
inwards,  and  forming  a  simple  cavity  or  sac 
within  the  body  of  the  animal,  it  is  soon 
rendered  more  complex  in  its  structure,  being 
distributed  in  the  manner  of  vessels  under  the 
name  of  tracheae  or  canals  to  different  parts  of 
the  body,  or  being  confined  to  a  particular 
district,  and  entitled  lungs  or  gills  as  it  is  fitted 
to  receive  the  atmospheric  air  immediately,  or 
lo  make  use  of  this  elastic  fluid  suspended  or 
dissolved  in  water. 

The  existence  of  this  separate  respiratory 
apparatus  presupposes  that  of  another  system, 
namely,  the  circulatory.  The  fluids  prepared 
by  the  organs  of  digestion  are  not  yet  fitted  to 
minister  to  the  growth  and  nutrition  of  the 
organization ;  to  be  made  apt  for  this  purpose 
they  require  exposure  to  the  air  in  the  lungs  or 
gills  wherever  these  organs  exist,  and  these  be- 
ing distinct,  or  contained  in  a  particular  region 
of  the  body,  a  series  of  conduits  were  re- 
quired, first  to  carry  the  fluids  thither,  and 
to  transmit  them  subsequently  to  every  part  of 
the  organization  for  its  support.  Like  all  the 
other  systems  of  animals,  the  circulatory  exists 
of  various  degrees  of  complexness;  when  first 
encountered  it  consists  of  a  series  of  simple 
canals  or  vessels,  which  diverge  on  every  hand ; 
by-and-by  it  has  several,  and  finally  one,  forc- 
ing piece,  or  heart  superadded  to  it,  which 
impels  the  fluids  by  its  contractions  to  every 
the  most  remote  part  of  the  organization. 

Among  animals,  however,  nutrition  is  not  a 
process  simply  of  addition  or  composition ; 
it  is  also,  perhaps  universally,  one  of  subtrac- 
tion or  of  decomposition.  We  have  seen  the 
composition  provided  for  by  special  systems 
in  animals  occupying  very  low  grades  in  the 
scale  of  creation ;  we  mount  but  a  short  way 
before  we  encounter  an  apparatus  which  pre- 
sides over  the  decomposition  also  in  the  shape 
of  another  system  of  vessels,  the  veins  and 
especially  the  lymphatics ;  these  collect  the 
superfluous  and  worn-out  particles  from  every 
part,  pour  them  into  the  general  current  of  the 
circulation,  wherein  being  exposed  in  the  vital 
elaboratory  of  the  lungs  they  are  either  assi- 
milated anew  and  made  fit  once  more  to  form 
an  integral  part  of  the  organization,  or,  being 
subjected  to  the  action  of  certain  glands,  they 
are  singled  out,  abstracted,  and  finally  ejected 
from  the  system  entirely.  In  the  most  com- 
plicated animals  therefore  a  peculiar  appa- 
ratus for  the  depuration  of  the  system  is  su- 
peradded as  complementary  to  the  absorbents. 
This  we  find  in  the  glandular  bodies  familiarly 
known  as  the  kidneys ;  the  vehicle  in  which  the 
decayed  particles  are  withdrawn  is  the  urine. 

W  hen  we  examine  the  instruments  of  sensa- 
tion, we  find  them  becoming  gradually  more 


ANIMAL. 


141 


and  more  numerous,  and  the  nervous  system 
generally  more  and  more  complicated  as  we 
rise  in  the  scale  of  animal  creation.  The  ner- 
vous system  is  before  long  found  to  consist  of 
other  parts  than  a  series  of  similar  ganglions 
supplying  at  once  the  organs  of  sensation  and 
those  of  digestion ;  it  has  a  central  part  super- 
added,  from  which  issue  immediately  the 
nerves  that  supply  the  organs  of  the  senses, — 
sight,  hearing,  taste,  and  smell,  which  at  the 
same  time  make  their  appearance  with  their 
especial  capacities.  This  central  superadded 
portion  is  the  brain,  with  its  prolongation  in 
the  vertebrata  entitled  spinal  marrow.  Nor  in 
the  more  perfect  classes  of  the  animal  king- 
dom is  the  nervous  system  even  thus  simple  ; 
among  them  it  consists  essentially  of  two 
grand  divisions,  the  one  including  the  brain 
and  spinal  cord  and  the  nerves  thence  pro- 
ceeding, the  other  constituted  by  the  system  of 
the  great  sympathetic,  or  that  series  of  ganglions 
which,  situated  on  either  side  of  the  vertebral 
column,  from  the  head  to  the  pelvis,  are  con- 
nected with  one  another,  and  with  the  cerebro- 
spinal  system,  by  branches  of  communication, 
and  furnish  the  digestive  apparatus  with  almost 
the  whole  of  the  numerous  nerves  it  receives. 

The  nervous  system  in  its  relative  degree  of 
development  and  complexity  becomes  the 
ultimate  standard  by  which  the  perfection  of 
animals  is  estimated,  and  their  place  in  the 
scale  of  creation  assigned  to  them  :  if  man 
stand  alone  and  unattended,  as  he  undoubtedly 
does,  upon  the  summit  of  the  pyramid,  it  is 
only  because  he  possesses  in  his  brain  the 
organs  of  certain  moral  and  intellectual  facul- 
ties which  occur  in  no  other  living  thing;  these 
confer  on  him  his  humanity;  these  are  the  ma- 
terial parts  to  which  the  soul  is  wedded  during 
his  existence. 

In  intimate  connection  with  the  functions  of 
phrenic  or  animal  life,  and  developed  nearly 
in  the  same  ratio,  is  the  muscular  system,  the 
most  universal  agent  of  locomotion.  Exceed- 
ingly simple  at  first,  and  operating  at  great 
disadvantage  through  a  want  of  levers  and 
points  of  support,  we  trace  it  becoming  gra- 
dually more  complicated  as  we  ascend,  and, 
finally,  provided  with  a  complementary  skeleton 
or  frame-work  by  means  of  which  it  acts  to  the 
best  advantage.  The  skeleton  among  animals 
is  of  two  kinds, — external  and  horny,  internal 
and  osseous.  In  the  first  case  the  muscular 
system  is  inclosed  within  the  resisting  pieces 
which  it  has  to  move;  in  the  second  it  is 
without  these,  and  is  arranged  around  them. 
The  bones  and  muscles  together  compose  the 
numerous  and  variously  fashioned  instruments 
with  which  animals  accomplish  the  promptings 
of  their  inward  appetites  and  instincts.  They 
form  feet,  fins,  hands,  the  prehensile  tail,  &c. 
The  muscular  system,  and  a  modification  of 
the  osseous,  the  cartilaginous,  moreover,  com- 
pose the  most  universal  instrument  by  which 
animals  communicate  their  vicinity,  their  states, 
their  dispositions  or  affections,  &c.  to  one  ano- 
ther— this  is  the  larynx. 

The  means  by  which  species  are  continued, 
are  extremely  varied.  The  very  lowest  tribes 


of  animals  we  have  seen  shooting  forth  buds 
exactly  like  vegetables,  and  these  being  in  due 
season  detached  from  the  body  of  the  parent, 
find  themselves  fitted  to  commence  an  inde- 
pendent existence.  At  the  next  step  we  take 
in  ascent,  however,  we  meet  with  particular 
organs  of  reproduction ;  and,  singular  enough, 
the  moment  these  exist  they  are  not  of  one, 
but  of  two  kinds,  denominated  male  and  fe- 
male. Sometimes  these  organs  are  possessed 
by  single  individuals,  far  more  commonly, 
however,  they  are  divided  between  two,  whence 
the  so  uniform  division  of  the  beings  com- 
posing the  animal  kingdom  into  sexes.  The 
simplest  form  of  the  male  organ  of  generation 
is  a  gland  secreting  a  fecundating  fluid  (the 
testis)  and  an  excretory  duct:  the  simplest 
form  of  the  female  apparatus  of  generation  is 
a  gland  or  body  producing  germs  (the  ovary) 
and  an  excretory  duct.  In  a  greater  state  of 
complication  or  development  these  essential 
parts  in  the  male  have  an  instrument  super- 
added  to  them  by  which  the  fecundating  fluid 
is  carried  directly  into  the  body  of  the  female, 
and  in  the  female  the  ovary  has  a  dilatable 
cavity  superadded  in  which  the  germ  remains 
for  a  season,  and  until  its  included  embryo 
attains  such  a  state  of  development  as  is  com- 
patible with  its  more  independent  existence 
surrounded  by  the  circumstances  amid  which 
it  is  afterwards  to  live.  In  the  higher  classes, 
the  connection  between  the  parent  and  offspring 
does  not  cease  immediately  on  the  birth  of 
the  latter,  and  in  the  highest  of  all  we  find 
the  female  furnished  with  a  complementary 
apparatus  (the  mammae),  from  which  she  fur- 
nishes her  young  with  food  during  the  first 
period  of  Its  existence. 

Actions  of  animals. — The  foregoing  rapid 
sketch  of  the  grand  features  of  distinction 
among  animals  with  reference  to  their  struc- 
ture naturally  leads  to  the  inference  of  di- 
versity of  function  in  harmony  with  the  pecu- 
liar organization  possessed  by  each.  In  the 
lowest  grades  of  animal  existence  we  have 
seen  to  how  simple  a  process  the  act  of  nutrition 
— this  act  so  complicated  among  the  more 
elevated  tribes, — is  reduced.  It  consists  merely 
of  imbibition  or  absorption  by  and  of  exha- 
lation from  the  general  surface  of  the  body. 
The  matters  absorbed  appear  to  be  assimilated 
incontinently,  or  to  be  made  a  part  of,  and  to 
receive  the  form  proper  to,  the  animal  in  the 
instant  of  their  assumption:  applied  imme- 
diately to  the  homogeneous  organism,  the 
nutriment  is  forthwith  made  a  portion  of  its 
substance.  The  vital  decomposition  of  the 
bodies  of  these  lower  animals  is  accomplished 
with  the  same  simplicity  and  directness :  the 
surface  that  absorbs  is  also  that  which  exhales 
the  worn-out  particles  of  the  system. 

The  first  step  by  which  nutrition  becomes 
more  complex,  as  we  rise  in  the  scale  of  cre- 
ation, is  the  institution  of  a  process  of  solution 
(digestion),  by  which  the  matters  appropriated 
as  aliment  are  prepared  for  reception  into 
the  body.  This  process  of  solution  is  accom- 
plished by  powers  inherent  in  the  animal  itself, 
within  a  cavity  destined  for  the  purpose.  In 


142 


ANIMAL. 


our  survey  of  the  structure  we  have  already 
seen  to  how  great  an  extent  the  organization 
became  complicated  as  a  consequence  of*  this 
centralization  of  the  office  of  digestion,  and 
with  what  variety  of  superadded  function  this 
complication  was  attended,  namely,  external 
absorption,  sanguification  or  the  formation  of 
a  fluid,  the  pabulum  of  nutrition,  confined 
within  vessels,  respiration,  circulation,  and, 
finally,  assimilation,  in  regard  to  the  compo- 
sition ;  whilst  with  reference  to  the  vital  de- 
compositions we  have  discovered  another  spe- 
cies of  interstitial  or  internal  absorption,  and 
depuration  of  the  system  by  one  principal 
apparatus,  the  kidney,  to  which  the  cutaneous 
and  pulmonary  exhalations  may  be  added  as 
supplementary. 

But  every  one  of  these  functions,  and  its 
organic  apparatus,  are  themselves  modified, 
according  to  internal  aptitude,  and  in  con- 
formity with  the  circumstances  surrounded  by 
which  animals  commence  and  continue  their 
existence.  Digestion  is  a  very  simple  process 
in  those  cases  in  which  it  takes  place  within 
a  single  cavity,  having  but  one  opening,  and 
no  complementary  apparatus  of  any  kind, 
compared  with  what  it  is  when  connected  with 
an  apparatus  for  bruising  the  food,  for  mixing 
it  with  saliva,  for  macerating  it  in  a  crop  or  a 
series  of  reticulated  and  foliaceous  pouches, 
mixing  it  with  bile,  pancreatic  juice,  &c.  &c., 
and  transmitting  it  along  a  muscular  canal, 
of  six,  eight,  or  ten  times  the  length  of  the 
body  to  which  it  belongs. 

Absorption,  in  like  manner,  among  the  most 
inferior  classes  is  essentially  one  and  undi- 
vided either  in  kind  or  destination.  It  is  in 
itself  adequate  to  the  entire  office  of  nutrition, 
seizing  and  transmitting  the  matters  which  are 
fitted  for  this  end,  elaborating  the  food  and 
atmospheric  air  at  the  same  instant  of  time, 
and  effecting  immediately  the  composition  of 
the  whole  animal  organism.  In  animals  higher 
in  the  scale,  we  perceive,  in  the  first  place,  that 
there  are  several  species  of  absorption :  there 
is,  in  the  first  place,  the  absorption  from  the 
surface  of  the  digestive  passages  and  that  from 
the  surface  of  the  lungs,  gills,  skin,  &c.  or  of 
the  respiratory  apparatus.  Again,  absorption  is 
not  limited  to  furnishing  materials  for  the  com- 
position of  the  organism  ;  it  is  also  entrusted 
with  the  office  of  abstracting  from  its  interior 
the  particles  which  are  worn  out  and  no  longer 
fit  to  continue  the  ends  of  their  existence  in 
the  places  they  occupy.  Nor  is  this  all ;  for 
it  is  by  absorption  that  the  amount  of  those 
exhaled  fluids  which  moisten  internal  cavities, 
having  no  external  communications,  is  regu- 
lated, and  by  which,  as  it  would  appear,  many 
of  the  secreted  fluids,  the  bile,  and  the  sper- 
matic fluid  in  particular,  are  inspissated  and 
rendered  more  fit  to  accomplish  the  important 
ends  they  subserve  in  the  economy.  Absorp- 
tion in  the  highest  classes  of  all  is  even  per- 
formed by  two,  and  perhaps  three  different 
orders  of  vessels,  the  lacteals,  namely,  the 
lymphatics,  and  the  veins. 

Further,  absorption  is  not  in  the  higher  as 
it  is  in  the  lower  classes  of  animals  a  function 


effecting  immediately  the  composition  and  de- 
composition of  the  parts  and  particles  of  the 
organization.  It  is  intermediate  to  the  pre- 
paration of  the  nutritious  juices  and  their  ap- 
propriation or  assimilation  by  the  organism. 
The  lacteals  or  absorbent  vessels  of  the  in- 
testines collect  the  fluid  called  chyle  from  the 
pultaceous  alimentary  mass  in  its  progress 
through  the  intestines.  But  this  fluid  is  not 
yet  fitted  to  subserve  nutrition;  as  a  pre- 
liminary it  has  to  be  subjected  to  the  action 
of  the  atmospheric  air  in  the  gills,  lungs,  &c., 
where,  being  converted  into  arterial  blood,  it 
first  becomes  apt  to  minister  to  the  growth 
and  reparation  of  the  body  and  its  parts.  So 
also  in  regard  to  decomposition :  the  fluids 
collected  from  all  parts  by  the  lymphatics  and 
veins,  are  not  immediately  rejected  from  the 
economy,  as  useless  and  having  already  accom- 
plished all  of  which  they  are  susceptible,  but 
being  first  exposed  to  the  contact  of  the  at- 
mosphere, and  then  made  to  undergo  the 
scrutiny  of  the  depurative  organs,  they  are 
either  retained,  being  restored  to  their  pristine 
capacity  to  subserve  nutrition,  or  are  abstracted 
from  and  thrown  out  of  the  body  as  no  longer 
fit  to  aid  in  its  growth  and  maintenance. 

Intercourse  with  the  air  of  the  atmosphere  is 
essential  to  every  living  thing,  and  we  should  a 
priori  have  anticipated  very  considerable  variety 
in  the  means  by  which,  as  well  as  the  mode  in 
which  this  intercourse  is  established.  Among 
the  inferior  tribes  which  are  nourished  by  ab- 
sorption immediately  from  the  surface  of  their 
body,  and  which  find  the  materials  of  their 
nutrition  ready  prepared  for  their  use  in  the 
circumambient  media,  we  may  presume  that 
the  matters  absorbed  have  either  undergone 
the  needful  changes  by  exposure  to  the  air 
previously  to  their  assumption,  or  that  these 
changes  take  place  at  the  time  they  are  ap- 
propriated. Where  digestion  is  a  preliminary 
to  absorption  and  assimilation,  it  is  evident 
that  this  could  not  have  been  the  case;  and 
hence  the  necessity  for  that  modification  of  the 
function  of  aeration  entitled  respiration.  Look- 
ing generally,  we  observe  two  principal  varieties 
in  the  mode  by  which  aeration  is  accomplished : 
in  some  classes  there  are  a  number  of  holes 
arranged  symmetrically  along  the  sides,  and 
communicating  with  air-vessels  entitled  tra- 
cheae, which  are  subsequently  distributed  to 
every  part  of  the  body.  The  air  in  this  case 
is  evidently  brought  into  communication  with 
the  nutrient  juices  already  arrived  at  their 
destinations ;  and  the  necessary  changes  are 
wrought  in  them  at  the  instant  of  their  assimi- 
lation. Here  the  respiration  is  very  properly 
said  to  be  diffuse  or  disseminated.  In  other 
classes,  again,  in  which  the  respiration  is  local 
or  concentrated,  in  harmony  with  the  existence 
of  a  special  apparatus,  which  we  have  spoken 
of  under  the  title  of  lung  or  gill,  aeration  is 
accomplished  by  the  access  of  the  air  on  the 
one  hand,  and  the  exposure  to  its  action  of  the 
nutritive  fluid  on  the  other,  the  effect  of  which 
is  to  convert  the  latter  into  arterial  blood,  and 
to  make  it  fit,  upon  its  distribution  by  appro- 
priate channels,  to  accomplish  the  ultimate  and 


ANIMAL. 


143 


immediate  nourishment  of  every  part  of  the 
organization. 

The  different  media  in  which  animals  live 
involves  the  supposition  of  another  modifica- 
tion as  to  the  mode  in  which  the  blood  or 
nutritive  fluid  is  aerated.  Those  that  live  in 
air  respire  this  elastic  fluid  immediately;  those 
that  live  in  water,  again,  respire  it  mingled 
with  or  dissolved  in  the  surrounding  medium. 
The  tracheae  of  those  animals  whose  respira- 
tion is  diffuse,  and  that  exist  on  the  surface 
of  the  earth,  consequently  are  filled  with  air; 
those  of  the  creatures  that  exist  in  water  are 
conduits  for  the  constant  transmission  of  this 
fluid.  When  the  respiration  is  concentrated, 
corresponding  modifications  in  the  function 
are  encountered  according  to  the  medium  in 
which  animals  live :  the  air  is  either  received 
immediately  into  the  body, when  the  apparatus 
is  known  as  a  lung,  or,  suspended  among 
water,  it  is  passed  over  the  surface  of  the 
respiratory  organ,  which  is  then  denominated 
gill.  Quadrupeds  and  birds  respire  univer- 
sally by  means  of  lungs,  fishes  and  the  mol- 
lusca  by  means  of  gills.  In  certain  reptiles 
the  function  is  carried  on  by  means  both  of 
lungs  and  gills,  and  as  it  would  appear  even 
by  the  general  surface  of  the  body  either  vica- 
riously, or  at  one  and  the  same  time.  These 
are  the  only  true  amphibious  animals. 

A  circulation,  properly  so  called,  is  the  ap- 
panage of  an  organization  already  somewhat 
complicated,  consequently  of  an  animal  con- 
siderably raised  in  the  scale  of  creation.  This 
function,  it  is  evident,  as  implying  in  its  sim- 
plest sense  a  progressive  motion  of  the  general 
nutritive  fluid  or  blood,  can  only  exist  where 
such  a  fluid  is  encountered.  It  is  altogether 
wanting,  therefore,  among  those  animals  in 
which  nutrition  is  accomplished  immediately. 
We  ascend  but  a  little  way  in  the  scale  before 
we  find  the  function  consisting  not  only  of  an 
outward  or  progressive  motion  of  the  nutritive 
fluids,  but  of  a  retrograde  motion  also  of  these 
same  fluids  modified  in  their  nature,  and  re- 
quiring exposure  to  a  greater  or  less  degree  in 
some  form  of  respiratory  apparatus  to  fit  them 
anew  for  distribution  to  the  organization  at 
large.  The  fluid  in  this  instance  parts  from 
a  centre,  and  returns  thither  after  having  made 
the  round  of  the  system.  Circulation  in  this 
acceptation  only  occurs  among  those  animals 
that  have  a  separate  respiratory  apparatus,  and 
in  which  we  meet  with  absorption  of  nutri- 
ment from  without,  and  of  lymph,  &c.  from 
within.  The  pabulum  of  nutrition  is  taken 
up  by  lacteals  and  veins  from  the  digestive 
apparatus,  and  by  veins  and  lymphatics  from 
the  rest  of  the  organism  for  transmission,  under 
the  name  of  venous  blood,  to  the  apparatus  of 
respiration,  whatever  its  form.  In  this  the 
fluid,  still  immature  and  unapt  for  assimilation, 
is  exposed  in  vessels  of  infinite  minuteness 
and  extreme  tenuity  to  the  action  of  the  at- 
mospheric air,  and  having  undergone  in  these 
a  certain  change,  it  begins  to  be  collected  by 
another  set  of  vessels,  which  form  branches  suc- 
cessively of  larger  and  larger  size,  until  finally 
it  is  projected  from  the  respiratory  apparatus  in 


one  or  more  trunks,  under  the  name  of  arterial 
blood,  fitted  for  assimilation  by  the  organization 
at  large,  and  proving  the  principal  stimulus 
under  the  influence  of  which  its  various  par- 
ticular organs  accomplish  their  offices. 

Circulation,  however,  as  a  function,  is  com- 
plicated in  the  same  degree  as  the  apparatus 
by  which  it  is  effected.  In  some  classes  we 
find  the  circulation  taking  placing  through 
vessels  ow/y,  one  set  distributing  the  blood  from 
the  respiratory  apparatus  to  the  body  generally, 
another  collecting  this  fluid  again,  and  the 
newly-absorbed  matters  from  the  body  at  large, 
and  transmitting  these  for  elaboration  anew  in 
the  organ  of  respiration.  In  other  tribes,  and 
this  invariably  after  the  very  lowest  grades  of 
the  scale  are  passed,  we  find  the  hollow  muscle, 
or  forcing  apparatus,  which,  in  glancing  at  the 
differences  of  structure,  we  have  spoken  of 
as  the  heart  superadded  to  the  circle  of  vessels, 
which  even  in  its  simplest  state  consists  of 
at  least  two  cavities  communicating  with  one 
another,  one  for  the  reception  of  the  blood 
from,  the  other  for  the  projection  of  this  fluid 
to  the  general  system. 

But  the  blood  does  not  follow  the  direct 
and  simple  course  here  supposed  in  almost 
any  case.  There  is  the  aeration  of  the  fluid 
in  the  way,  and  means  to  accomplish  this 
important  end  must  of  course  be  provided. 
Among  many  animals  it  would  appear  by 
no  means  necessary  that  the  whole  of  the 
blood  should  undergo  exposure  in  the  respira- 
tory apparatus,  in  order  to  fit  it  for  the  wants 
of  the  organization  ;  a  part  only  is  sent  thither, 
and  this  on  admixture  with  the  remainder 
suffices  to  revivify  the  mass.  In  this  case  it 
is  not  imperative  that  the  two  kinds  of  blood — 
the  unaerated  or  venous,  and  the  aerated  or 
arterial — should  be  kept  distinct;  there  is  con- 
sequently no  occasion  for  more  than  one  re- 
cipient cavity  or  auricle,  into  which  the  aerated 
blood  from  the  organ  of  respiration,  and  the 
unaerated  blood  of  the  system  are  poured  in 
common  and  mingled,  and  one  projecting 
cavity  or  ventricle  from  which  the  mixed  cur- 
rent is  distributed  partly  to  the  respiratory  ap- 
paratus and  partly  to  the  system  at  large. 
Here  the  blood  in  its  course  describes  no  more 
than  a  single  circle,  beginning  and  ending  in 
the  heart,  which  is  then  characterized  as  simple, 
consisting,  as  has  been  said,  of  a  single  auricle 
and  a  single  ventricle.  Among  other  tribes  of 
animals,  however,  the  whole  mass  of  blood 
requires  to  undergo  aeration  in  the  respiratory 
apparatus  each  time  it  completes  its  round 
before  it  can  again  subserve  the  wants  of  the 
organization.  In  this  instance  it  is  evident  that 
the  aerated  and  unaerated  blood  require  to  be 
most  particularly  prevented  from  commingling, 
and  that  a  single  or  simple  heart  will  no  longer 
suffice  as  the  implement  of  circulation.  This 
complex  circulation  is  met  with  among  ani- 
mals so  low  in  the  scale  as  to  be  unprovided 
with  a  heart,  v\hen  of  course  it  is  accomplished 
by  means  of  vessels  only.  In  some  tribes  the 
one  portion  of  the  function  is  performed  by  the 
medium  of  vessels,  the  other  by  the  agency  of 
a  heart  which  is  now  connected  with  the  gene- 


144 


ANIMAL. 


ral  systemic  circulation,  now  with  the  pul- 
monic,  being  situated  in  the  one  case  in  the 
course  of  the  aerated,  in  the  other  in  that  of 
the  unaerated  current  of  blood.  In  the  most 
elevated  classes  of  animals,  finally,  the  double 
circulation  is  effected  by  means  of  two  hearts, 
one  dedicated  to  the  projection  of  the  un- 
aerated blood  into  the  lungs,  the  other  to  the 
propulsion  of  the  aerated  fluid  through  the 
general  system.  These  two  hearts,  indeed, 
adhere  to  one  another,  and  are  usually  spoken 
of  as  if  they  constituted  no  more  than  a  single 
organ,  having  however  four  cavities,  two 
auricles  and  two  ventricles,  but  they  are 
not  less  distinct  on  that  account,  and  are 
severally  the  centre  of  a  particular  circula- 
tory system,  one  of  which  commencing  in  the 
cavities  for  the  venous  or  unaerated  blood,  ex- 
tends through  the  respiratory  apparatus  (then 
uniformly  a  lung),  and  back  to  the  cavities  for 
the  arterial  aerated  blood ;  the  other,  com- 
mencing in  the  cavities  just  named,  extends  to 
every  part  of  the  organization,  and  terminates 
in  the  cavities  for  the  unaerated  blood,  where 
the  lesser  round  recommences,  to  be  followed 
in  its  turn  by  the  greater,  and  so  on,  during 
the  whole  period  of  existence. 

Assimilation  appears  to  be  identical  in  all 
animals;  it  is  the  ultimate  term  of  nutrition, 
and  however  varied  the  apparatus  that  minis- 
ters to  the  act,  the  act  itself  we  may  presume 
not  to  differ  in  its  essence  in  one  animal  from 
what  it  is  in  another. 

Akin  to  assimilation  we  have  secretion,  and 
this  is  a  function  that  offers  extensive  differences 
in  every  class  of  the  animal  kingdom.  It  is 
generally  spoken  of  as  of  two  kinds,  excretion, 
and  secretion,  properly  so  called.  In  the  lowest 
tribes  excretion  is  quite  simple,  consisting  of  a 
mere  exhalation  from  the  general  surface  of  the 
body.  In  the  more  elevated  we  find  another 
and  very  important  form  of  excretion  super- 
added,  that,  namely,  of  the  urine,  the  nature  of 
which,  and  the  mode  in  which  it  takes  place, 
we  have  already  indicated  in  speaking  of  the 
structure.  Secretion,  however,  even  in  the 
classes  but  a  little  raised  above  the  lowest,  is  a 
function  of  much  more  varied  import,  and  con- 
sists of  a  great  many  other  processes  than  that 
by  which  the  bodies  of  animals  are  depurated 
and  their  blood  maintained  in  a  state  fit  to 
supply  all  the  wants  of  the  system.  We  ad- 
vance but  a  little  way  before  we  begin  to  detect 
distinct  organs  destined  for  the  secretion  of 
peculiar  fluids  from  the  general  mass  of  cir- 
culating nutriment,  evidently  subservient  in 
many  cases  to  the  most  important  ends  of  the 
economy,  and  by  no  means  destined  to  be 
rejected  from  the  system  as  useless,  like  the 
excretions  properly  so  called.  It  seems  even 
that  it  is  by  a  process  analogous  to  secretion 
that  the  imponderable  matters — the  heat,  light, 
and  electricity,  which  we  have  acknowledged 
as  elements  in  the  constitution  of  organized 
beings,  are  eliminated. 

All  animals  possess  sensibility  or  sensation, 
though  evidently  in  the  most  dissimilar  degrees. 
Some  have  been  supposed  to  possess  the  faculty 
of  perceiving  impressions  made  upon  them  by 


external  objects,  but  to  have  no  power  of  re- 
acting upon  external  nature,  they  being  without 
the  faculties  which  in  the  higher  classes  prompt 
to  action.  This  state;  however,  of  animal  ex- 
istence is  rather  hypothetical  than  demonstrable, 
and  in  animals  generally  we  observe  not  only  the 
aptitude  to  be  impressed,  but  inherent  capacities 
inducing  reaction  upon  the  world  around  them. 
The  sensitive  life  of  these  beings  consequently 
consists  of  two  items — the  senses  and  their 
organs,  external  and  internal,  by  which  im- 
pressions are  received  and  cognized,  and  the 
affective  and  intellectual  faculties  by  which  the 
motives  to  action,  the  propensities,  sentiments, 
instincts,  appetites,  &c.,  are  originated,  and 
the  means  and  modes  of  accomplishing  their 
promptings  are  supplied. 

Animals  evidently  differ  immensely  in  the 
degrees  in  which  they  are  endowed  with  ex- 
ternal and  internal  senses.  Some  appear  to 
possess  none  of  the  external  senses  save  touch  ; 
others,  in  addition  to  this,  have  taste  and  smell ; 
the  most  perfect  besides  these  three  reckon 
sight  and  hearing.  The  internal  senses,  in  like 
manner,  are  more  or  less  acute,  more  or  less 
numerous,  according  to  the  consitution  of  ani- 
mals :  those  of  hunger  and  thirst  are  probably 
universally  distributed,  and  the  most  keenly 
felt ;  then  come  those  which  induce  the  respira- 
tory act,  the  sexual  act,  &c. ;  and  here  we 
find  ourselves  among  the  propensities  which 
exist  in  very  different  numbers  and  kinds  in 
every  different  species  of  animal.  Some  tribes 
tend  their  offspring,  others  leave  their  progeny 
to  the  care  of  accident,  which  in  this  case 
always  suffices  for  their  protection  ;  some  con- 
gregate in  herds  or  shoals,  others  live  solitary 
or  in  pairs;  some  are  bold  and  rapacious, 
Others  timid  and  gentle,  &c.  When  we  ex- 
amine animals  generally,  with  reference  to  the 
sentiments  or  moral  faculties,  we  find  them 
still  more  or  less  like  each  other  in  many 
respects,  some  being  cautious  or  cowardly, 
proud  or  haughty,  persevering  or  obstinate,  &c., 
in  various  proportions.  When  we  contrast  all 
other  animals  with  man,  however,  in  regard  to 
moral  endowment,  we  immediately  perceive 
the  broad,  the  impassable  line  of  difference  that 
runs  between  the  lord  of  creation  and  all  the 
other  beings  that  with  him  partake  of  life.  The 
feeling  which  leads  man  to  view  his  actions  in 
their  bearing  upon  others  or  in  relation  to  jus- 
tice, is  extremely  weak  among  animals,  if  in- 
deed it  do  actually  exist  among  them  at  all. 
The  same  may  be  said  of  the  sentiment  which 
leads  mankind  to  wish  well  to  all,  and  to 
succour  and  relieve  those  that  are  suffering  and 
unfortunate.  The  feeling,  again,  that  raises 
man  to  the  imagination  of  a  something  beyond 
nature,  the  sentiment  that  inclines  him  to  reve- 
rence and  adore  his  Maker,  thus  in  one  way  re- 
vealed to  him,  and  the  wonderful  impulse  that 
leads  him  to  look  beyond  time  and  his  merely 
temporary  existence,  and  thence  to  conceive  in- 
finity and  eternity,  are  so  many  moral  attributes 
which  man  alone,  of  all  created  things,  possesses. 
Similar  diversities  in  intellectual  endowment 
are  apparent  when  we  survey  the  animal  king- 
dom at  large.  Intelligence  appears  utterly 


ANIMAL. 


145 


wanting  in  numerous  and  extensive  classes,  and 
it  varies  conspicuously  in  the  members  of  every 
tribe  among  which  it  is  apparent.  In  his  in- 
tellectual powers  man  is  not  less  eminently 
raised  above  all  the  other  beings  of  creation 
than  in  his  moral  constitution  :  he  alone  takes 
note  of  the  phenomena  that  pass  around  him 
with  ulterior  views,  and  he  alone  perceives  the 
relation  between  effect  and  cause,  preparing 
and  foreseeing  consequences  long  before  they 
happen. 

Locomotion  is  a  function  so  evidently  in  re- 
lation with  the  circumstances  surrounded  by 
which  animals  exist,  and  with  the  apparatus  by 
which  it  is  accomplished,  that  it  is  enough  to 
refer  back  to  the  structure  for  proof  and  illustra- 
tion of  its  infinite  modifications  among  the 
various  genera  and  species  of  the  animal  king- 
dom. Some,  by  their  constitution,  are  inca- 
pable of  motion  from  place  to  place,  but  they 
still  perform  those  partial  motions  which  their 
preservation  as  individuals  require — taking  their 
food,  respiring,  voiding  their  excretions,  &c. 
Those  that  can  move  from  one  place  to  another 
have  organs  in  relation  to  the  mode  in  which 
this  motion  is  accomplished,  whether  it  be  by 
creeping,  by  swimming,  by  running,  leaping, 
flying,  Sec.  &c.  Every  partial  movement  ex- 
ecuted by  the  higher  animals  has,  farther,  its 
own  special  apparatus  :  the  intestinal  canal  has 
its  muscular  parietes;  the  necessity  that  is  felt 
to  communicate  internal  sensations  and  ideas 
has  its  pathognomonic  means  in  the  looks, 
gestures,  sounds  of  the  voice,  and  so  on. 

Nor  is  it  only  in  the  greater  or  less  degree  of 
complexity  of  their  general  structure,  in  the  num- 
ber and  diversity  of  their  particular  organs,  or  in 
those  of  the  actions  whose  sum  constitutes  their 
vitality,that  animals  differ  from  one  another;  they 
vary  farther  in  the  degree  in  which  these  organs 
and  these  functions  are  enchained  or  mutually 
dependent.  In  the  most  simple  animals  so 
complete  is  the  independence  of  the  several 
parts,  that  their  bodies  may  be  divided  into 
numerous  pieces  without  injury  to  the  vitality 
of  any  one  of  them,  each  possessing  in  itself 
the  capacity  to  commence  a  separate  existence. 
In  animals  somewhat  more  elevated  in  the  scale 
we  observe  very  extensive  powers  of  reproduc- 
tion at  least,  of  parts  that  have  been  lost,  and  even 
of  continuing  existence  in  very  insignificant 
remainders  of  their  bodies.  In  the  most  ele- 
vated tribes,  however,  the  dependence  of  every 
part  upon  the  whole  becomes  such  that  neither 
will  the  body  essentially  mutilated  survive,  nor 
will  any  part  of  the  slightest  consequence  con- 
tinue to  live.  Among  the  beings  at  the  bottom 
of  the  scale  we  have  in  fact  found  the  organiza- 
tion to  be  homogeneous,  or  without  distinction 
of  parts,  and  nutrition  to  be  accomplished  by 
means  of  an  immediate  absorption  and  exhala- 
tion; and  as  every  part  possesses  the  structure 
which  makes  it  capable  of  these  two  acts,  every 
part,  it  is  evident,  suffices  for  its  own  existence. 
In  the  higher  classes  of  animal  existence,  how- 
ever, nutrition  requires  the  concurrence  of  a  mul- 
titude of  peculiar  acts ;  and  in  order  that  life  may 
be  continued  in  any  fragment  of  one  of  the  mem- 
bers of  these,  it  is  plain  that  this  fragment  must 

vor.  i. 


contain  the  organs  of  every  one  of  the  functions 
essential  to  nutrition.  Further,  it  is  certain  that 
the  nervous  system,  when  once  it  has  fairly  made 
its  appearance,  strictly  dominates  the  nutritive 
function,  and  that  every  part  of  the  nervous 
system  itself  becomes  progressively  more  and 
more  dependent  on  one  of  its  portions,  the 
encephalon  or  brain,  as  animals  stand  higher  in 
the  scale  of  creation,  and  as  the  functions  over 
which  the  nervous  parts  preside  respectively 
are  themselves  of  a  higher  order.  These  are 
new  and  additional  reasons  for  the  centraliza- 
tion of  life,  or  for  the  complete  dependence  of 
the  organs  and  their  functions  one  upon  another 
among  the  more  perfect  animals — man,  the 
quadrumans  and  quadrupeds,  birds,  &c. 

So  much  for  the  acts  that  minister  to  the 
preservation  of  the  individual.  Let  us  now  turn 
to  the  interesting  series  by  which  species  are 
continued.  In  the  very  lowest  grades  this  end 
is  accomplished  without  the  concurrence  of 
sexes  :  at  a  determinate  period  of  its  life  the 
animal  either  separates  into  several  fragments, 
which  become  so  many  new  and  independent 
individuals,  or  it  throws  out  a  number  of  buds 
or  germs  from  its  external  surface  or  from  a 
particular  internal  cavity.  The  first  of  these 
modes  of  reproduction  is  entitled  fissiparous, 
the  second  external  gemmiparous,  and  the  third 
internal  gemmiparous. 

When  we  examine  animals  in  the  next  grade, 
we  find  reproduction  taking  place  by  the  con- 
currence of  sexes,  or  rather  of  two  kinds  of 
organs  which  we  afterwards  discover  divided 
between  different  individuals,  who  are  then 
said  to  be  of  opposite  sexes.  When  the  male 
and  female  organs  are  united  in  the  same  indi- 
vidual it  is  denominated  an  hermaphrodite  ani- 
mal, and  in  some  cases  seems  to  suffice  for  its 
own  impregnation  ;  more  generally,  however, 
hermaphrodite  animals  are  not  capable  of  per- 
forming this  act  upon  themselves,  but  require 
the  concurrence  of  another  individual  of  similar 
constitution:  the  two  hermaphrodites  meet  and 
severally  impregnate  one  another. 

Among  the  more  perfect  classes  of  the  ani- 
mal kingdom  the  organs  of  reproduction  are 
universally  allotted  to  two  different  individuals, 
males  and  females,  which  consequently  become 
in  their  dualism  representatives  of  their  species. 
Agreeing  in  this  single  feature,  the  modifica- 
tions in  the  process  of  reproduction  are  never- 
theless extremely  numerous.  In  some  cases 
the  fecundating  fluid  of  the  male  is  only  ap- 
plied to  the  egg  or  germ  of  the  female  after  its 
extrusion  from  her  body,  as  happens  among 
fishes,  several  reptiles,  &c.;  in  others  the  male 
fluid  is  injected  into  the  body  of  the  female, 
and  made  to  fecundate  the  germ  still  attached 
to  its  parent.  This  act  is  generally,  though  not 
invariably,  accomplished  by  means  of  a  penis, 
or  male  external  organ,  with  which  many  birds 
and  all  the  animals  above  them  in  the  scale  of 
animal  creation  are  then  provided. 

With  this  contact  or  intermixture  of  bodies 
we  have  the  following  varieties  in  the  after-parts 
of  the  process :  the  egg  or  germ  now  fecun- 
dated is  either  forthwith  expelled  from  the 
body,  and  it  is  only  subsequently,  under  the  in- 


146 


ANIMAL. 


fluence  of  a  certain  temperature,  and  after  the 
lapse  of  a  certain  time,  that  the  young  being 
bursts  the  shell  and  commences  its  independent 
existence ;  this  is  the  case  among  oviparous 
animals.  Or  otherwise :  the  fecundated  egg 
makes  its  way  so  slowly  through  the  passages 
that  lead  from  the  ovary  outwards,  that  it  is 
hatched  before  it  can  escape,  so  that  the  young 
one  passes  from  the  body  of  the  mother  imme- 
diately. Animals  in  whom  this  happens  are 
justly  said  to  be  ova-viviparous.  In  the  third 
and  last  place,  the  fecundated  ovum  is  imme- 
diately loosened  from  the  ovary,  but  instead  of 
being  laid,  or  extruded  from  the  body  immedi- 
ately, it  only  passes  along  a  canal  to  a  certain 
distance  from  the  ovary,  where  it  meets  with  a 
reservoir  or  cavity  (the  uterus)  to  which  it  at- 
taches itself,  and  within  which  it  commences 
a  series  of  evolutions,  at  the  expense  of  the 
mother,  preliminary  to  its  final  expulsion  with 
instincts  ready  formed,  and  an  organization  so 
perfect  as  enables  it  to  begin  its  separate  ex- 
istence. The  classes  in  which  this  mode  of 
reproduction  obtains,  and  they  are  the  highest 
of  all,  including  quadrupeds  and  man,  are  en- 
titled viviparous,  so  that  in  these,  besides  the 
connection  of  the  sexes  and  the  fecundation  of 
the  germ,  we  have  the  phenomena  of  utero- 
gestation  and  labour. 

And  here  the  proper  work  of  reproduction 
ends;  but  the  young  are  so  generally  born  in 
some  sort  immature,  that  in  the  higher  classes 
the  connection  between  the  offspring  and  pa- 
rent does  not  cease  immediately.  In  the  class 
of  mammalia,  indeed,  the  connection  is  little 
less  intimate  during  the  earlier  periods  of  extra 
uterine  life  than  it  was  during  the  whole  term 
of  intra-uterine  existence  ;  the  young  being 
still  depends  upon  its  mother  for  the  whole  of 
its  nourishment,  and  very  generally  for  the 
supply  of  warmth  it  requires  and  the  protection 
needful  to  it  till  able  to  provide  for  itself. 

Many  of  the  particulars  now  merely  glanced 
at,  and  numerous  others,  the  mention  of  which 
has  been  omitted  entirely,  will  be  found  de- 
tailed, and  their  bearing  and  importance  illus- 
trated in  the  article  on  GENERATION,  to  which 
the  reader  is  therefore  referred. 

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REGION  OF  THE  ANKLE. 


147 


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Anatomic  generale.  The  systems  of  Physiology  of 
Adelon,  Bostock,  Burdach,  Magendie,  Mayo, 
Richerand,  Rudolphi,  and  Tiedeman.  (To  the 
admirable  Physiologic  of  the  last  mentioned  judi- 
cious, learned,  and  laborious  author,  the  writer  of 
the  present  article  stands  greatly  indebted.  The 
work  has  been  lately  translated  into  English  by 
Drs.  Gully  and  Lane.) 

( R.  Willis.) 

ANKLE,  REGION  OF  THE,  (surgical 
anatomy),  (region  tibio-tarsienne,  Velp.)  The 
relative  positions  and  other  particulars  con- 
nected with  the  parts  found  in  the  region  of  the 
ankle,  owing  to  the  numerous  accidents  which 
occur  here,  are  matters  of  great  interest  to  the 
surgeon.  The  extent  and  boundaries  of  this  re- 
gion are  by  no  means  so  distinctly  defined  as 
those  of  many  others  ;  hence,  in  isolating  it  for 
special  description,  the  surgical  anatomist  is 
obliged  to  assign  to  it  arbitrary  or  imaginary 
limits.  We  propose  to  adopt  the  following 
boundaries  for  this  region,  viz.  superiorly  a  hori- 
zontal line  drawn  round  the  leg  two  inches  above 


the  malleoli,  and  inferiorly  a  line  drawn  across 
the  dorsurn  and  sides  of  the  foot  at  the  same 
distance  from  those  bony  prominences.  In  this 
space  are  comprised  the  ankle-joint  and  several 
important  vessels,  tendons,  and  other  soft  parts 
well  worthy  of  attention. 

In  examining  the  external  characters  of  this 
region  we  notice  four  well-marked  prominences, 
one  on  either  side,  termed  malleotus,  (internus 
v.  externus) ;  a  third  posteriorly,  which  cor- 
responds to  the  tendo  Achillis;  and  a  fourth  in 
front,  resulting  from  the  projection  of  the  astra- 
galus. The  malleoli  do  not  accurately  corres- 
pond either  in  situation  or  shape  to  each  other : 
the  internal  lies  upon  a  plane  superior  and 
anterior  to  the  external,  and  in  a  well  formed 
person  is  much  less  sharp  and  prominent, — 
a  fact,  the  recollection  of  which  is  of  great  im- 
portance in  estimating  deformity  or  dislocation 
of  the  joint.  The  cylindrical  prominence  be- 
hind, as  it  depends  upon  the  tendo  Achillis, 
will  of  course  vary  in  size  and  tension  accord- 
ing to  the  relaxation  or  contraction  of  the 
gastrocnemii  muscles.  Upon  either  side  of 
the  tendo  Achillis,  between  it  and  the  malleo- 
lus  we  meet  with  a  deep  groove,  called  by 
some  the  calceo-malleolar  furrow :  that  upon 
the  outside  is  extremely  well  marked,  and  we 
may  here  distinctly  feel  through  the  integu- 
ments two  of  the  peronei  tendons :  the  internal 
calceo-malleolar  groove  is  broader  and  shal- 
lower, but  of  much  greater  interest,  for  through 
it,  in  addition  to  certain  tendons,  we  have 
transmitted  the  principal  vessels  and  nerves  des- 
tined for  the  sole  of  the  foot.  The  anterior 
prominence,  named  in  popular  language,  "  the 
instep,"  is  rounded  in  the  transverse  direction, 
and  in  some  individuals  projects  much  more 
than  in  others.  On  throwing  the  foot  and  toes 
into  action,  as  in  walking,  we  can  here  dis- 
tinctly recognize  the  tendons  of  the  tibialis 
anticus,  extensor  pollicis,  extensor  digitorum 
longus,  and  peroneus  tertius,  and  almost  in 
the  mesial  line  may  be  felt  pulsating  distinctly 
the  anterior  tibial  artery. 

Having  thus  examined  the  landmarks  which 
are  to  guide  us  in  our  anatomical  investigation 
of  this  region,  we  may  next  proceed  to  inquire 
into  the  nature  and  relations  of  its  constituent 
parts.  Besides  the  bones,  cartilages,  and  liga- 
ments which  immediately  constitute  the  joint, 
and  form  the  basis  of  the  region,  we  have  like- 
wise several  other  structures  entering  into  its 
formation ;  integuments,  muscles,  vessels, 
nerves,  and  fasciae  are  here  arranged  in  suc- 
cessive layers  beneath  each  other.  We  shall 
accordingly  describe  four  layers, —  namely, 
1.  the  skin;  2.  the  subcutaneous  cellular 
tissue;  3.  the  fasciae;  and  4.  the  tendons, 
vessels,  and  nerves,  which  lie  in  immediate 
contact  with  the  articulation. 

1.  The  skin  forms  a  complete  investment 
for  the  whole  region,  but  its  structure  and 
properties  differ  considerably  in  different  situ- 
ations. Upon  the  inner  ankle  it  i:i  smooth  and 
thin,  and  possessed  of  but  little  extensibility  ; 
so  that  in  operating  here,  if  we  look  forward 
to  union  by  the  first  intention,  it  becomes  a 
matter  of  great  moment  to  preserve  as  much 

i.  2 


148 


RKGION  OF  THE  ANKLE. 


of  the  skiu  as  possible.  Owing  to  the  same 
peculiarities  of  the  integuments  in  this  situ- 
ation, no  lebs  perhaps  than  to  the  frequent 
motion  of  the  part,  wounds  and  ulcers  occur- 
ring upon  the  inner  ankle  are  extremely  tedious 
and  troublesome,  in  many  instances  laying 
bare  the  bone,  and  finally  even  occasioning  its 
destruction.  Upon  the  outer  ankle,  the  skin 
is  more  pliant  and  extensible;  hence  the  greater 
facility  of  healing  wounds  and  ulcers  in  this 
part;  and  hence,  too,  the  more  frequent  occur- 
rence of  abscess  and  extravasation  beneath  the 
surface.  At  the  posterior  part  of  the  region 
the  skin  acquires  great  strength  and  thickness, 
becoming  as  it  passes  downwards  still  more 
dense  and  unyielding,  approximating  in  fact 
to  the  character  of  the  plantar  integument. 
Upon  the  instep  it  is  also  of  tolerable  thick- 
ness, particularly  in  those  individuals  whose 
feet  are  usually  uncovered.  In  this  situation, 
however,  it  is  soft  and  extensible :  its  natural 
pliancy  being  still  further  increased  by  the 
secretion  of  numerous  sebaceous  follicles 
thickly  scattered  throughout  its  substance.  It 
is  here,  owing  to  the  frequent  motions  of  the 
joint,  thrown  into  transverse  rugae,  and  hence, 
in  making  an  incision,  to  give  exit  to  matter, 
it  may  be  proper  to  prefer  a  transverse  to  a 
vertical  direction. 

2.  The  subcutaneous  cellular  tissue. — The 
structure  and  properties  of  the  subcutaneous 
cellular  tissue  are  not  the  same  throughout  the 
whole  region,  but  like  the  skin,  which  we 
have  just  considered,  its  characters  vary  in  dif- 
ferent situations.  Thus,  upon  the  instep,  it  is 
at  the  upper  part  loose  and  distensible,  full  of 
adipose  cells,  and  similar  in  every  respect  to 
the  subcutaneous  tissue  of  the  leg,  of  which  it 
is  a  prolongation :  as  it  descends,  however,  it 
becomes  more  dense  and  unyielding,  and  ad- 
heres more  closely  to  the  skin  which  covers, 
and  to  the  annular  ligament  which  is  placed 
beneath  it.  This  anatomical  fact  at  once  ex- 
plains why  it  is  that  when  subcutaneous  ab- 
scess or  infiltration  occurs  on  the  anterior  part 
of  the  leg  or  foot,  the  passage  of  the  fluid 
either  upwards  or  downwards  is,  for  a  time  at 
least,  impeded  at  the  ankle-joint.  It  is  like- 
wise owing  to  the  density  of  the  subcutaneous 
tissue  across  the  ankle,  that  its  cells  do  not 
permit  the  accumulation  of  adipose  substance 
here;  hence  in  very  fat  persons  and  also  in 
children  whose  subcutaneous  fat  is  usually 
abundant  upon  the  leg  and  foot,  the  instep  is 
as  it  were  strangulated  by  a  deep  transverse 
furrow.  Upon  the  malleoli  the  characters  of 
the  subcutaneous  tissue  present  great  differ- 
ences: upon  the  inner  one  it  is  scanty  and 
delicate,  but  of  a  compact  structure,  and  con- 
tains few  if  any  adipose  cells.  Upon  the  outer 
one  it  is,  on  the  contrary,  much  more  copious, 
of  a  loose  and  yielding  texture,  and  usually 
contains  a  greater  quantity  of  fat.  These  dif- 
ferences of  texture  will  explain  why,  after 
severe  contusion,  extravasations  so  frequently 
occur  upon  the  outer  part  of  the  joint  and 
so  seldom  upon  the  inner ;  why  abscess  is  so 
much  oftener  met  with  in  the  one  situation 
than  in  the  other ;  and  why  the  transmission 


of  pus  and  serum  from  any  of  the  neighbour- 
ing regions  takes  place  so  much  more  easily 
about  the  outer  than  about  the  inner  ankle. 
At  the  posterior  part  of  the  region,  the  sub- 
cutaneous tissue  assumes  again  new  characters  : 
losing  here  its  soft  lamellated  texture  it  be- 
comes suddenly  dense  and  filamentous,  ad- 
hering with  great  firmness  to  the  integuments 
above,  and  to  the  fascia  beneath :  as  we  trace 
it  down  it  becomes  more  dense  and  elastic ; 
the  cells  formed  by  the  decussation  of  its 
filaments  become  loaded  with  a  firm  granular 
fat;  in  a  word,  it  already  begins  to  put  on  the 
characters  of  the  dense  fibro-adipose  cushion, 
which  is  found  in  the  sole  of  the  foot.  Hence 
it  is  that  wounds  and  abscesses  of  the  part  we 
are  now  considering,  approach  in  character 
those  of  the  plantar  region  :  hence  the  slight 
swelling,  the  severe  pain  ;  hence  in  both  cases 
the  necessity  of  a  prompt  and  free  evacuation 
of  the  matter. 

Before  leaving  this  subject  we  should  ob- 
serve that  the  subcutaneous  tissue  of  the  region 
we  are  now  considering  transmits  certain  ves- 
sels and  nerves.  In  front  of  the  inner  ankle 
we  meet  with  the  incipient  branches  of  the 
great  saphena  vein  and  the  ultimate  filaments 
of  the  saphenus  nerve :  the  venous  branches 
are  here  of  such  a  size  that  they  have  fre- 
quently been  selected  by  the  phlebotomist  as 
the  seat  of  operation.  Anteriorly  we  find  the 
filaments  of  the  musculo-cutaneous  nerve,  and 
externally  the  roots  of  the  lesser  saphena  vein, 
and  its  accompanying  nervous  filaments. 

3.  The  fascia  or  aponeurosis  forms  the  next 
stratum  we  have  to  examine:  it  is  placed  be- 
tween the  subcutaneous  tissue  and  the  tendons. 
The  fascia,  like  the  two  preceding  layers,  forms 
a  general  investment  for  the  whole  region. 
Its  structure  and  properties,  like  those  of  the 
preceding  layers,  vary  considerably,  according 
to  the  situation  in  which  we  view  it.  Upon 
the  instep  it  becomes  continuous,  above  with 
the  aponeurosis  of  the  leg,  and  inferiorly 
with  the  dorsal  aponeurosis  of  the  foot,  but, 
for  very  obvious  reasons,  surpassing  both  of 
these  in  strength.  This  additional  strength  is 
owing  to  the  accessory  band  of  fibres  which 
passes  transversely  across  the  instep,  interlaced 
with  the  proper  oblique  fibres  of  the  fascia, 
and  to  which  is  given  the  name  of  anterior 
annular  ligament.  Arising  from  the  anterior 
edge  of  the  inner  ankle  this  annular  ligament 
passes  outwards  and  soon  meets  with  the  ten- 
don of  the  tibialis  anticus :  at  this  point  it 
splits  into  two  layers ;  the  one  passes  before, 
the  other  behind  the  tendon,  and  they  unite 
again  at  its  outer  edge.  The  same  mechanism 
is  repeated  in  the  case  of  the  extensor  pollicis 
tendon  which  lies  immediately  external  to  the 
last-named  tendon ;  and  lastly  in  those  of  the 
extensor  digitorum  longus  and  peroneus  tertius. 
In  contemplating  the  mechanism  and  uses  of 
this  ligament,  the  surgical  anatomist  cannot 
but  perceive  that  certain  inconveniences  must 
result  from  its  division :  its  use  being  obviously 
to  bind  down  the  tendons  in  this  situation,  and 
to  form  canals  for  their  free  and  separate  trans- 
mission, it  is  clear  that  after  its  division  in  the 


KECiiON  OF  THE  ANKLE. 


living  subject,  when  the  individual  attempts  to 
flex  the  foot  or  extend  the  toes,  these  tendons 
will  not  only  form  an  unseemly  projection 
upon  the  instep,  but  also  the  accuracy  and  per- 
fection of  these  motions  will  be  much  im- 
paired. Upon  the  lateral  parts  of  the  region, 
the  fascia  is  so  intimately  united  to  the  peri- 
osteum, that  it  is  almost  impossible  to  separate 
them  from  each  other,  and  hence  some  have 
denied  its  existence  here.  Behind  both  mal- 
leoli,  it  becomes  however  again  very  distinct, 
forming  in  both  situations  a  band  similar  to 
that  which  we  have  just  seen  upon  the  instep. 
The  internal  annular  ligament  arising  from 
the  posterior  edge  of  the  inner  malleolus 
passes  backwards  to  the  os  calcis;  it  is 
thrown  like  a  bridge  across  that  deep  gutter 
which  divides  the  heel  and  ankle  from  each 
other,  and  it  is  destined  like  the  anterior  liga- 
ment to  form  a  covering  to  the  tendons  and 
other  parts  which  pass  through  this  region. 
Like  the  anterior,  the  internal  ligament  also 
consists  of  two  layers  closely  united  to  each 
other.  To  express  more  distinctly  the  me- 
chanical disposition  of  these  layers,  we  may 
say  that  the  bridge  formed  by  the  internal 
annular  ligament  consists  of  two  arches  ; 
through  the  anterior  arch  are  transmitted  the 
tibialis  posticus  and  the  flexor  digitorum 
longus  tendons,  wrapped  each  in  its  own 
synovial  theca :  the  posterior  arch  is  occupied 
with  the  posterior  tibial  vessels  and  nerves, 
and  the  tendon  of  the  flexor  longus  pollicis 
muscle.  Having  thus  safely  conducted  these 
important  organs,  the  superficial  layer  of  the 
ligament  fixes  itself  into  the  os  calcis,  while 
the  deep  one  passes  backwards  and  upwards 
to  become  continuous  with  the  deep  fascia  of 
the  leg.  Behind  the  external  malleolus,  the 
fascia  forms  another  but  less  remarkable  liga- 
ment, which  Blandin  calls  the  "  external  an- 
nular:" this  passes  from  the  fibula  to  the 
astragalus,  and  forms  with  the  posterior  edge 
of  the  malleolus  a  deep  osseo-fibrous  canal  for 
the  transmission  of  the  peroneus  longus  and 
brevis  tendons. 

At  the  back  part  of  this  region,  t!ie  fascia  is 
also  found  covering  the  great  tendo  Achillis  ; 
this  tendon  also,  like  the  smaller  ones  we  have 
just  spoken  of,  is  not  merely  covered  super- 
ficially, but  is  contained  within  a  sheath, 
formed  by  the  splitting  of  the  fascia  into  two 
layers  :  the  posterior  layer  we  may  regard  as 
the  continued  fascia  itself;  the  deep  one  passes 
in  front  of  the  tendon,  and  if  we  trace  this  up- 
wards, we  shall  find  it  becoming  ultimately 
continuous  with  the  deep  fascia  of  the  leg.  An 
acquaintance  with  the  disposition  and  structure 
of  the  fascia  we  have  thus  described,  will  en- 
able the  surgical  anatomist,  in  almost  every  in- 
stance, to  explain  the  time,  situation,  and  pro- 
gress of  abscesses  occurring  in  this  region:  he 
will  at  once  comprehend  that  three  distinct 
sorts  of  abscess  may  form  here  : — one  in  the 
subcutaneous  tissue,  and  which  being  super- 
ficial to  the  fascia  can  hardly  penetrate  deeply 
toward  the  joint ;  another,  occurring  between 
the  two  layers  of  that  membrane,  in  those 
situations  where  it  splits  to  include  the  ten- 


dons ;  such  an  abscess  will  have  little  tendency 
to  point  in  front,  being  bound  down  by  the 
superficial  layer  of  the  fascia,  or  to  penetrate 
deeply  for  a  similar  reason ;  but  to  its  free 
passage  upwards  or  downwards  in  the  course 
of  the  tendons,  little  or  no  obstacle  is  presented. 
Lastly,  matter  may  accumulate  under  both 
layers  of  the  fascia,  where  its  deep  position  and 
close  confinement  render  it  alike  dangerous,  and 
of  difficult  detection. 

4.  The  next  stratum  is  perhaps  less  entitled 
to  that  name  than  those  we  have  hitherto 
described.  Instead  of  forming,  like  them,  a 
general  investment  for  the  whole  region,  it 
consists  of  several  distinct  and  independent  or- 
gans scattered  irregularly  about  the  joint :  we 
shall  enumerate  them  in  the  order  in  which  we 
propose  to  treat  of  them,  viz.,  tendons,  mus- 
cles, arteries,  veins,  lymphatics,  and  nerves. 

a.  Tendons.  Upon  the  instep  we  find  no 
fewer  than  seven  tendons  passing  towards  the 
foot :  the  internal  is  the  largest  of  all,  it  is  that 
of  the  tibialis  anticus  running  obliquely  for- 
wards and  inwards  to  the  inner  cuneiform  bone. 
Close  upon  its  outer  side  is  the  tendon  of  the 
extensor  pollicis  ;  still  more  outwards  we  meet 
with  the  four  tendons  of  the  extensor  digitorum 
longus,  and  most  externally  of  all,  or  nearest 
to  the  outer  ankle,  that  of  the  peroneus  tertius. 
We  need  not  revert  to  the  subject  of  the  fibrous 
sheaths  furnished  to  these  tendons  by  the  fascia 
or  annular  ligament;  but  we  should  here  care- 
fully observe,  that  both  sheaths  and  tendons  are 
completely  lined  by  a  synovial  apparatus.  He 
who  is  at  all  acquainted  with  the  general  patho- 
logy of  synovial  membrane  will  understand  why 
it  is  that  effusions  so  frequently  form  about  the 
instep  ;  why  adhesion  of  the  opposite  walls  of 
these  synovial  sheaths  will  almost  destroy  the 
power  of  extending  the  toes  and  of  flexing  the 
foot ;  and,  lastly,  he  cannot  but  draw  the  im- 
portant practical  deduction,  that  in  operations 
about  the  instep  we  should  avoid,  if  possible, 
cutting  into  these  synovial  sacs. 

Behind  the  inner  malleolus  we  meet  with 
three  tendons,  —  that  of  the  tibialis  posticus 
most  anterior,  and  in  close  connexion  with  the 
posterior  surface  of  the  malleolus  internus;  that 
of  the  flexor  digitorum  longus  a  little  further 
back ;  and  still  more  posterior,  and  at  a  little 
distance  from  the  others,  the  tendon  of  the 
flexor  pollicis  longus.  These  are  included,  as 
we  have  already  explained,  in  fibrous  sheaths 
formed  by  the  internal  annular  ligament,  each 
sheath  and  tendon  having  its  own  synovial 
lining.  We  may  here  observe  a  good  anatomical 
reason,  why  inflammation  affecting  the  sheath 
of  the  flexor  digitorum  will,  cateris  paribus, 
be  more  likely  to  prove  dangerous  than  that  of 
the  tibialis  posticus :  for,  as  the  synovial  sheaths 
of  the  former  extend  along  the  whole  sole  of  the 
foot,  little  or  no  obstacle  is  presented  to  the 
disease  extending  itself  into  that  region  :  whereas 
the  tendon  of  the  tibialis  being  inserted,  not. 
upon  the  sole,  but  rather  upon  the  inner  edge 
of  the  foot,  its  synovnl  membrane  forms  here 
a  cul-de-sac,  no  doubt  presenting  some  obsta- 
cle to  the  inflammation  extending  beyond  this 
point.  Behind  the  outer  malleolus  there  exists 


150 


REGION  OF  THE  ANKLE. 


a  deep  groove,  in  which  two  important  tendons 
are  contained,  those,  namely,  of  the  peroneus 
longus  and  brevis.  They  are  lodged  in  a  canal 
which  we  have  already  described  as  formed  by 
the  bone  and  the  external  annular  ligament, 
and  this  canal  is  lined  by  a  distinct  synovial 
membrane  reflected  upon  it  from  the  tendons. 
Having  passed  over  the  ligaments  of  the  outer 
ankle,  the  peronei  tendons  are  next  applied 
upon  the  surface  of  the  os  calcis;  and  here, 
though  previously  in  close  apposition,  and  in- 
deed contained  within  the  same  synovial  sheath, 
they  become  separated  by  a  ridge  projecting 
from  the  bone.  The  peroneus  longus  tendon  plays 
behind  it  as  upon  a  pulley,  and  instances  have 
occurred,  where,  owing  to  the  fracture  of  this 
little  osseous  septum,  the  peroneus  longus  has 
been  dislocated  forwards  upon  that  of  the 
brevis.  It  has  also  happened  that  both  peronei 
tendons  have  been  dislocated  forwards  from 
their  groove  behind  the  malleolus,  and  thrown 
in  front  of  that  eminence.  Were  such  an  acci- 
dent left  without  surgical  interference,  it  is  inte- 
resting to  reflect  how  completely  altered  would 
be  the  action  of  these  two  muscles,  if  that  action 
were  not  completely  suspended  by  the  inflam- 
mation and  obliteration  of  the  synovial  sheath 
consequent  on  the  accident ;  instead  of  extend- 
ing the  foot  and  pointing  the  toe,  as  they  do  in 
their  natural  state,  they  would  become  con- 
verted into  flexors  and  abductors  of  the  foot. 
At  the  posterior  part  of  the  region,  the  tendo 
Achillis  forms  a  remarkable  projection.  In  our 
account  of  the  fascia,  we  have  described  the 
sheath  within  which  this  tendon  is  contained. 
We  may  further  observe  that  this  tendon  is 
separated  from  the  joint,  and  also  from  the 
deep  vessels  and  nerves  of  the  leg,  by  a  consi- 
derable interval,  so  that  it  has  frequently  been 
cut  across  without  injury  to  the  articulation  or 
wound  of  any  other  important  part.  Its  mode 
of  insertion  into  the  os  calcis  is  also  worthy 
attention ;  instead  of  being  fixed  into  the  whole 
posterior  surface  of  that  bone,  it  occupies  by 
its  insertion  merely  the  lower  half  of  it ;  supe- 
riorly the  bone  and  tendon  are  not  even  in  con- 
tact, for  here  a  distinct  synovial  bursa  is  inter- 
posed between  them.  The  liability  of  this 
large  bursa  to  inflammation  and  effusion  should 
be  carefully  borne  in  mind  by  the  surgeon  :  and 
he  who  is  aware  of  its  office,  placed  as  a  friction 
roller  between  the  tendon  and  bone,  will  duly 
estimate  how  much  disease  of  this  bursa  will 
impede  the  motions  of  progression.  Owing  to 
the  interposition  of  the  bursa,  rupture  of  the 
tendo  Achillis  has  occurred  even  below  the 
upper  edge  of  the  os  calcis  ;  and  if,  having  cut 
across  the  tendon,  we  forcibly  extend  the  foot 
so  as  to  elevate  the  heel,  we  shall  at  once  com- 
prehend how  indispensably  necessary  it  is  to 
maintain  the  extended  position  in  our  treatment 
of  this  important  accident. 

b.  Muscles. — There  are  bu  t  few  muscular  fibres 
met  with  in  the  region  of  the  ankle :  the  flexor 
digitorum  brevis  arises  upon  the  instep ;  and 
posteriorly  we  find  some  of  the  fibres  of  the 
flexor  pollicis  longus,  which  are  here  continued 
down  a  considerable  way  upon  the  tendon. 

c.  Arteries. — The  arteries  about  the  ankle. 


from  their  liability  to  injury  and  disease,  become 
of  great  interest.  Upon  the  instep  the  course 
and  relations  of  the  anterior  tibial  artery  de- 
mand particular  attention;  the  vessel  here 
does  not  run  exactly  in  the  median  line  of  the 
foot,  but  is  somewhat  nearer  to  the  inner  than 
to  the  outer  malleolus :  we  may  always  reach 
it  with  perfect  certainty,  by  cutting  between  the 
tendon  of  the  extensor  digitorum  longus,  and 
that  of  the  extensor  pollicis ;  these  overlap  it 
upon  either  side,  and  afford  considerable  protec- 
tion against  wounds  or  other  injuries.  Not- 
withstanding the  facility  of  reaching  the  vessel 
in  this  situation,  it  is  by  no  means  advisable  to 
do  so  when  it  is  at  all  possible  to  avoid  it,  inas- 
much as  to  expose  the  artery  here  it  is  necessary 
to  wound  the  synovial  sheaths,  and  inflammation 
and  adhesionwould  be  the  probable  consequence 
of  such  an  injury.  The  branches  of  the  in- 
ternal malleolar  artery  are  found  upon  the 
inner  part  of  the  region,  running  upon  and  in 
front  of  the  inner  ankle,  and  anastomosing  with 
others  passing  forwards  from  the  posterior 
tibial,  thus  insuring  a  sufficient  supply  of  blood 
to  the  joint,  even  when  the  trunk  of  the  anterior 
tibial  itself  has  been  tied.  But  these  vessels 
are  of  much  inferior  importance  compared  with 
the  posterior  tibial,  whose  main  trunk  lies  in 
the  fossa  between  the  heel  and  the  malleolus 
internus.  It  is  here  occasionally  the  subject  of 
operation,  and  hence  its  course  and  relations 
should  be  very  carefully  noted.  We  have  al- 
ready enumerated  the  tendons  passing  beneath 
the  annular  ligament  in  this  situation  ;  the  most 
anterior  is  that  of  the  tibialis  posticus,  imme- 
diately behind  it  lies  that  of  the  flexor  digi- 
torum, and  still  more  posteriorly,  at  the  interval 
of  about  an  inch,  is  found  the  tendon  of  the 
flexor  pollicis ;  in  this  interval  between  the  two" 
latter  tendons  runs  the  posterior  tibial  artery, 
not  however  equidistant  from  both,  but  nearer 
to  that  of  the  flexor  digitorum ;  it  rests  upon 
the  tibia  and  internal  tibio-tarsal  ligament,  and 
is  covered  by  the  integuments  and  annular 
ligament;  its  venae  comites  run  one  upon 
either  side ;  and  the  posterior  tibial  nerve  lies 
close  behind  it,  but  as  the  vessel  descends  get- 
ting gradually  to  its  inner  side.  Notwith- 
standing the  few  coverings  of  the  artery  in  this 
situation,  yet  owing  to  the  heel,  the  ankle,  and 
the  tendo  Achillis  projecting  around,  and  bearing 
off  as  it  were  those  coverings  from  it,  the  vessel 
is  here  at  a  considerable  depth  from  the  surface ; 
and  any  one  who  supposes  it  can  be  easily  found 
in  the  living  subject,  will  form  a  very  erroneous 
idea  of  its  true  position : — hence  it  i*  that  all 
good  writers  on  surgical  anatomy  recommend 
us  to  take  up  the  artery  in  the  lower  third  of 
the  leg,  rather  than  in  the  calceo-malleolar 
groove.  Several  small  vessels  ramify  about 
the  outer  ankle,  the  external  malleolar  coming 
from  before  meets  here  with  the  terminating 
branches  of  the  peroneal  artery  from  behind,  but 
these  small  vessels  are  interesting  to  the  sur- 
gical pathologist  rather  than  to  the  regional 
anatomist  or  operative  surgeon. 

d.  Veins. — Two  veins,  the  "  venae  comites," 
accompany  each  of  the  larger  arteries :  in  all 
operations  upon  the  artery,  the  close  apposition 


JOINT  OF  THE  ANKLE. 


151 


of  the  veins,  and  the  possibility  of  mistaking 
one  for  the  other,  should  be  remembered  by 
the  surgeon.  In  front  of  the  inner  malleolus 
we  observe  one  or  two  openings  in  the  fascia, 
through  which  small  branches  of  communication 
pass  between  the  superficial  and  deep  veins; 
these,  no  doubt,  are  the  principal  channels 
through  which  the  venous  blood  of  the  integu- 
ments about  the  foot  and  instep  is  returned, 
after  the  operation  of  tying  the  great  saphena 
vein. 

e.  Lymphatic*. — The  lymphatics  consist  like- 
wise of  two  sets ;    the  one  lying  beneath   the 
integuments  and  scattered  irregularly  over  the 
region ;  the  other  lying  beneath  the  fascia,  and 
for  the  most   part  accompanying   the   blood- 
vessels.   Some  anatomists  speak  of  a  lymphatic 
gland   lying  upon    the   instep,    and    receiving 
several  of  these  deep  absorbents ;  in  the  majo- 
rity of  cases  there  is  no  such  gland,  and  its 
existence    in    any    appears    to    us    extremely 
doubtful. 

f.  Nerves. — The  nerves  in  this  region  have 
the  same  general  distribution   as   the  arteries. 
In  our  account  of  the  larger  arteries,  we  have 
already  minutely  assigned  the  relation  which 
their  accompanying  nerves  bear  to  them.     We 
may  thus  briefly  enumerate  them : — in   front, 
the   musculo-cutaneous  and  anterior  tibial ;  on 
the  inner  side  the  terminal  ramifications  of  the 
internal  saphenus  and  the  posterior  tibial ;  and 
on  the  outside,  the  terminal   branches  of  the 
external  saphenus.     For  further  particulars  re- 
specting the  nerves,  we  refer  to   the   articles 
LUMBAR  NERVES;  SACRAL  NERVES. 

For  the  BIBLIOGRAPHY  of  this  article  and  all 
others  on  surgical  anatomy,  see  the  Bibliography 
of  ANATOMY  (INTRODUCTION.) 

(John  E.  Brenan.) 

ANKLE,  JOINT  OF  THE.— (Normal  ana- 
tomy.) (Fr.  articulation  du  coude-pied.  Germ. 
Fusagelenk.  Ital.  caviglia.)  The  ankle-joint,  or 
tibio-tarsal  articulation,  results  from  the  junc- 
tion of  the  leg  and  foot.  For  reasons  which 
will  appear  when  we  come  to  explain  its  mo- 
tions, it  is  ranked  in  the  excellent  and  com- 
prehensive classifications  of  Bichat  andCloquet 
as  a  perfect  angular  ginglymus.  The  security 
of  the  ankle-joint,  more  perhaps  than  of  any 
other  in  the  body,  is  owing  to  the  peculiar 
form  of  its  bones,  and  to  their  exact  adap- 
tation to  each  other;  in  this  respect  it  has 
aptly  been  compared  to  the  tenon  and  mortise 
joint,  so  frequently  used  by  mechanics,  the 
strength  of  which,  as  is  well  known,  is  chiefly 
owing  to  the  peculiar  form  and  close  fitting  of 
its  component  parts.  Upon  the  "pper  part  of 
the  foot,  we  meet  with,  it  is  said,  a  true  and  well 
defined  tenon,  and  upon  the  lower  part  of  the 
leg  a  tolerably  perfect  mortise  for  the  reception 
of  the  tenon.  The  comparison,  though  perhaps 
not  strictly  correct,  will  however  assist  us  in 
understanding  how  much  the  security  of  this 
joint  depends  upon  the  form  and  fitting  of  its 
bones  ;  and  will  explain  to  the  beginner  why, 
in  treating  of  the  ankle-joint  in  particular  with 
a  view  to  demonstrate  its  use  and  mechanism, 
a  brief  account  of  its  bones  becomes  par)  of  our 


description  no  less  essential  than  of  its  liga- 
ments themselves.  In  our  account,  therefore, 
of  this  articulation,  we  shall,  in  the  first  place, 
describe  its  bones;  next  its  ligaments;  and, 
lastly,  shall  offer  some  remarks  upon  its  me- 
chanism and  uses. 

a.  The  Bones. — Three  bones  contribute  to 
the  formation  of  the  ankle-joint;  the  tibia  and 
fibula  form,  by  the  union  of  their  inferior  por- 
tions, a  deep  depression,  into  which  the  head  of 
the  astragalus  is  received.  The  tibia,  as  it  ap- 
proaches the  joint,  looses  gradually  its  prismatic 
shape,  and  assumes  a  well-defined  cubical  or 
quadrangular  form.  On  its  lower  extremity  it 
presents  a  quadrilateral  articulating  cavity, 
covered  in  the  recent  state  with  cartilage ;  this 
cavity  is  transversed  from  before  backwards  by 
an  obtuse  ridge  which  subdivides  it  into  two 
smaller  cavities.  Of  the  four  sides  or  margins 
of  this  articulating  cavity,  the  anterior  is  almost 
straight  transversely,  but  convex  or  rounded  off 
in  the  vertical  direction,  with  the  obvious  design 
of  permitting  a  greater  flexion  to  the  foot;  the 
anterior  tibio-tarsal  ligament  arises  from  this 
margin.  The  posterior  margin  is  also  straight 
transversely,  but  vertically  convex,  to  permit  an 
increased  extension  to  the  foot ;  the  posterior 
tibio-fibular  ligament  is  connected  here :  a 
shallow  oblique  groove  is  met  with  upon  the 
outer  part  of  this  surface,  for  the  transmission 
of  the  flexor  longus  pollicis  tendon.  The  ex- 
ternal side  presents  a  depression  for  the  reception 
of  the  fibula ;  this  articulating  portion  is  pro- 
longed upwards  for  nearly  an  inch,  is  of  a 
triangular  form  with  the  base  below ;  the  sides 
of  the  triangle  give  attachment  to  the  anterior 
and  posterior  tibio-fibular  ligaments ;  and  the 
area  of  the  triangle  is  rendered  rough,  except  at 
its  lowest  part,  by  the  attachment  of  the  inferior 
interosseous  ligament, — another  strong  bond  of 
union  between  these  bones.  The  inner  edge  is 
prolonged  downwards  nearly  an  inch  in  length, 
forming  the  prominence  known  by  the  name  of 
malleolus  internus;  this  is  placed  upon  a  plane 
superior  and  anterior  to  the  malleolus  externus; 
it  is  somewhat  flattened  in  shape,  and  has  one 
surface  looking  inwards  or  towards  the  mesial 
line  ;  this  in  the  living  subject  is  covered  only 
by  the  integuments ;  the  outer  surface  enters 
into  the  formation  of  the  joint,  hence  it  is 
tipped  with  cartilage  to  permit  the  astragalus  to 
play  upon  it;  the  anterior  edge  is  sharp  and 
gives  origin  to  the  anterior  tibio-tarsal  ligament; 
the  posterior  edge  is  traversed  by  a  broad  and 
generally  well-marked  groove,  which  transmits 
the  tendons  of  the  tibialis  posticus  and  flexor 
digitorum  longus ;  the  apex  of  the  malleolus 
is  below,  and  gives  attachment  to  the  deltoid  or 
internal  tibio-tarsal  ligament. 

Thejibula,  as  it  approaches  the  foot,  becomes 
suddenly  enlarged  in  size,  applies  itself  firmly 
to  the  tibia,  and  then  descends  nearly  an  inch 
and  a  half  below  its  point  of  union  with  that 
bone.  The  prominence  formed  by  the  fibula 
in  this  situation  is  named  the  malleolus  externus ; 
it  is  much  larger  than  the  internal,  and  placed 
behind  and  somewhat  below  it.  The  external 
surface  of  this  fibular  maHeohis  is  covered 
merely  l>y  the  integuments  ;  the  internal  surface 


JOINT  OF  THE  ANKLE. 


is  tipped  with  cartilage,  and  convex  in  the  ver- 
tical direction,  being  received  upon  a  corres- 
ponding concavity  on  the  outer  side  of  the 
astragalus;  upon  the  lower  and  back  part  of 
this  inner  surface  may  be  seen  a  deep  depres- 
sion, where  the  posterior  fibulo-tarsal  ligament 
arises;  the  anterior  edge  of  the  malleolus  is 
sharp,  and  gives  origin  to  the  anterior  fibulo- 
tarsal  ligament ;  the  posterior  edge  is  marked 
by  a  deep  groove,  whieh  transmits  the  tendons 
of  the  peronei  muscles,  longus  and  brevis. 
The  apex  of  the  malleolus  is  below,  and  gives 
origin  to  the  middle  fibulo-tarsal  ligament. 

The  astragalus  enters  into  the  formation  of 
the  ankle-joint  by  its  superior  surface,  and  a 
portion  of  its  two  lateral  surfaces.  On  the 
superior  surface  we  observe,  anteriorly,  a  well 
marked  groove  forming  part  of  the  neck  of  the 
astragalus  ;  into  this  groove  the  anterior  tibio- 
tarsal  ligament  is  inserted.  Immediately  be- 
hind the  groove  we  meet  with  an  articulating 
eminence  of  an  oblong  quadrilateral  form,  an 
inch  and  a  half  in  its  antero-posterior,  and  about 
an  inch  and  a  quarter  in  its  transverse  measure- 
ment; (this  transverse  measurement  is,  however, 
a  little  greater  in  front  than  behind ;)  the  emi- 
nence is  remarkably  convex  from  before  back- 
wards, and  concave  from  side  to  side ;  the  outer 
edge  somewhat  more  elevated  than  the  inner  ; 
it  is  completely  covered  with  cartilage,  and  cor- 
responds to  the  articulating  cavity  upon  the  in- 
ferior exremity  of  the  tibia.  Upon  the  inner 
side  of  the  astragalus,  we  find  a  small  articu- 
lating surface  of  a  triangular  form,  with  the 
base  above  and  apex  below;  it  is  convex  in 
the  vertical  direction,  and  is  tipped  with  car- 
tilage prolonged  ftom  the  superior  surface: 
upon  thetriangular  surface  the  internal  malleolus 
plays  ;  the  remaining  portion  of  the  inner  side 
of  the  astragalus  is  rough,  and  occupied  chiefly 
by  the  insertion  of  the  internal  tibio-tarsal 
ligament.  The  external  side  of  the  astragalus 
is  also  marked  by  an  articulating  surface  of  a 
much  greater  size  for  the  reception  of  the  ex- 
ternal malleolus :  it  too  is  of  a  triangular  form 
with  the  base  above ;  concave  in  the  vertical, 
and  slightly  convex  in  the  antero-posterior 
direction. 

b.  Ligaments. — We  have  already  compared 
the  mechanism  of  this  joint  to  that  of  the  tenon 
and  mortise ;  the  mortise  cavity,  however,  is  not, 
as  we  have  seen,  cut  out  of  a  solid  bone,  but 
teing  formed  in  great  part  in  the  lower  extremity 
of  the  tibia,  is  completed  on  the  outer,  side  by 
the  fibula,  which  is  firmly  united  with  the  tibia 
by  strong  ligaments,  forming  what  is  called  the 
i  nferior  tibw-fibulur  articulation.  We  shall  not 
now  describe  the  ligaments  which  here  unite  the 
tibia  and  fibula,  referring  to  the  article  on  the 

TlBlO-FIBULAR  ARTICULATION  ;    but  W6  must 

observe  that,  however  it  may  be  advisable,  in 
anatomical  descriptions,  to  separate  this  last 
named  articulation  from  the  ankle-joint,  they 
are  perfectly  inseparable  in  their  functions,  the 
integrity  of  the  latter  being  essentially  dependent 
on  that  of  the  former :  indeed  it  may  be  said, 
that,  by  virtue  of  the  great  strength  of  the  liga- 
mentous  connexion  between  the  tibia  and  fibula 
in  the  former  articulation,  the  mortise  is  n* 


strong,  nay,  in  some  respects  stronger,  than  if  it 
had  been  formed  out  of  solid  bone. 

The  ligaments  which  connect  the  tenon  and 
mortise  together,  or  to  speak  more  literally, 
which  tie  the  tibia  and  fibula  with  the  tarsus, 
are  five  in  number,  namely,  two  tibio-tarsal 
and  three  fibulo-tarsal  ligaments. 

1 .  The  internal  tibio-tarsal  ligament  is  also 
called  the  internal  lateral,  and  by  Weitbrecht 
the  deltoid  ligament.     There  is,  however,  no 
reason  why  we  should  not  apply  to  it  likewise 
that  principle  of  nomenclature  which  is  so  gene- 
rally and  with  such  advantage  applied  to  other 
ligaments.     It  arises  by  a  truncated  apex  from 
the  point  of  the  inner  malleolus,  and  from  the 
little  fossa  at  its  outer  surface ;  its  fibres  change 
as  they  proceed  downwards  and  are  fixed  into 
the  inner  surface  of  the  astragalus  and  os  calcis, 
some  proceeding  as  far  forwards  even  as  the 
scaphoid  bone.     The  posterior  fibres  are  strong 
but  short ;    the  anterior  are  much  larger  and 
not  so  thick.     Its  internal  surface  is  lined  by 
the  synovial  membrane  of  the  joint;  and  on  its 
internal  surface  it  is  covered  by  the  tendon  of 
the  tibialis  posticus,  and  it  sends  some  of  its 
fibres    to     the  sheath    of    the   flexor   longus 
digitorum  tendon.     In  flexion  of  the  leg  the 
anterior  fibres  are  relaxed,  and  the  posterior  are 
rendered   tense:    in   extension   the  reverse  of 
course  takes   place.      2.  The  anterior   tibio- 
tarsal  ligament  (lig.  tibio-tarsal,  Cloquet)  con- 
sists of  a  few  loose  fibres  scattered  over  the 
synovial  membrane,  and  in  some  instances  so 
delicate  and  so  separated  by  pellicles  of  fat  as 
to  be  scarcely  perceptible.    They  arise  from 
the  fore  part  of  the  inner  malleolus  and  the 
adjacent  anterior  portion  of  the  tibia,  and  de- 
scend obliquely   downwards  and  outwards  to 
be  inserted  into   the  neck   of  the   astragalus. 
This  ligament  is  covered  anteriorly  by  the  ten- 
dons of  the  tibialis  anticus,  extensor  proprius 
pollicis,  and  extensor  digitorum  longus  :  poste- 
riorly it  is  in  contact  with  the  synovial  mem- 
brane.    3.  The  anterior  fibulo-tarsal  ligament 
(lig.fibule  anterius,  Weitb.,  anterior  external 
lateral,  Boyer)  arises  from  the  anterior  edge  of 
the  outer  malleolus,  a  few  lines  from  its  ex- 
tremity;   it  descends  obliquely  forwards  and 
inwards,  and  is  fixed  into  the  astragalus  imme- 
diately in  front  of  the  articulating  surface  which 
receives  the  fibula:   it  is  scarcely  an  inch  in 
length,  of  an  oblong  quadrilateral  form,  and  is 
frequently  subdivided  into  two  distinct  parts. 
In  extension  of  the  foot  it  is  rendered  tense ; 
in  flexion  it  is  relaxed.     4.  The  middle  fibulo- 
tarsal  ligament   ( lig.  fibula   medium  perpen- 
diculare,   Weitb.,   external    lateral    ligament, 
Cloq.)  is  a  round  fasciculus  of  fibres  having 
almost  the  appearance  of  a  tendon  which  arises 
from  the  apex  of  the  external  malleolus,  de- 
scends obliquely  backwards,   and  is  attached 
to   the  outside   of  the    os    calcis.      It    does 
not  appear  to  us  that  in  any  position  of  the 
joint  this  ligament  takes  a  perpendicular  course, 
although  that  epithet  has  been  applied  to  it  by 
Weitbrecht.     It  is  related  superficially  to  the 
peroneus  longus  tendon,  and  by  its  deep  sur- 
face to   the  synovial  membrane,  to  the  astra- 
galus, and  os  calcis.     In  flexion  of  the  foot  this 


JOINT  OF  THE  ANKLK. 


153 


ligament  is  rendered  tense ;  hence  it  appears 
designed  to  limit  motion  in  this  direction  :  in 
extension  it  is  of  course  relaxed.  5.  The  /ws- 
teriorjibulo-tarsal\\ga.mei}t(  lig.  fibula  postcrius, 
Weitb.,  posterior  external  later  at,  Boyer)  arises 
from  the  little  fossa  upon  the  inner  and  back 
part  of  the  outer  malleolus ;  it  passes  backwards 
and  inwards  almost  horizontally,  or  at  least  de- 
scends very  slightly,  and  is  inserted  upon  the 
back  part  of  the  astragalus  into  the  outer  edge 
of  that  groove  which  transmits  the  flexor  longus 
pollicis  tendon.  This  ligament  is  stronger  than 
either  of  the  two  preceding,  and  is  frequently 
divided  into  several  distinct  fasciculi.  From 
its  superior  edge  an  accessory  band  sometimes 
passes  upwards  and  inwards  over  the  synovial 
capsule  to  be  fixed  into  the  tibia.  Walther 
has  described  this  band  under  the  name  of  the 
oblique  ligament,  and  it  is  well  represented  by 
Weitbrecht  (jig.  65,  tab.  xxii.) 

The  synovial  membrane  of  the  ankle-joint  is 
of  very  great  extent :  it  lines  not  only  the 
articular  surface  of  each  malleolus,  the  several 
ligaments  we  have  just  described,  and  the 
articulating  cavity  upon  the  lower  portion  of 
the  tibia,  but  it  is  prolonged  upwards  between 
the  tibia  and  fibula,  forming  in  that  situation  a 
little  cul-de-sac  :  this,  however,  is  merely  for  the 
extent  of  a  few  lines,  for  its  further  progress  up- 
wards is  interrupted  by  the  inferior  interosseous 
ligament,  (Jig.  61.)  From  the  circumference 
of  the  tibio-fibular  mortise  the  synovial  mem- 
brane passes  downwards  upon  the  astragalus, 
covers  its  superior  articulating  eminence,  and 
sends  prolongations  upon  its  lateral  articulating 
surfaces.  It  is  remarkably  loose  upon  the 
anterior  and  posterior  parts  of  the  joint,  and  is 
said  to  contain  a  greater  quantity  of  synovia 
than  any  other  synovial  membrane  in  the  body. 
Certainly  its  strength  is  much  increased  by 
those  scattered  fibres  to  which  we  have  given 
the  name  of  anterior  tibio-tarsal  ligament  : 
posteriorly  it  is  weakest,  for  here  few  if  any 
ligamentous  fibres  can  be  detected,  though 
Boyer  and  Weitbrecht  speak  confidently  of 
such. 

c.  Mechanism  and  function  of  the  ankle-joint. 
— To  understand  properly  the  mechanism  and 
function  of  the  ankle-joint,  we  must  carefully 
contemplate  it  in  the  opposite  conditions  of  rest 
and  motion. 

1.  Viewing  it,  then,  in  the  first  place,  as  the 
individual  stands  at  rest,  we  observe  that  the 
leg  and  foot  meet  each  other  in  the  ankle-joint 
at  a  right  angle,  and  we  are  particularly  struck 
with  this  fact  upon  finding  that  this  disposition 
occurs  in  scarcely  any  other  animal  than  man. 
This  interesting  fact  in  comparative  anatomy  is 
by  no  means  an  accidental  arrangement;  its 
design  is  obviously  in  reference  to  the  proper 
position  of  the  body  in  each  animal.  It  has, 
for  instance,  frequently  been  alluded  to  as  one 
of  the  many  anatomical  proofs  that  the  erect 
position  is  natural  to  the  human  subject :  had 
the  leg  and  foot  been  articulated  at  any  other 
than  a  right  angle  the  upright  position  of  the 
body  could  not  be  maintained,  at  least  without 
great  and  incessant  muscular  exertion.  Another 


point  worthy  of  our  attention  is  that  when  the 
ankle  is  at  rest  and  the  body  in  the  upright 
position,  the  fibula  plays  no  part  in  the  func- 
tion performed  by  the  joint :  it  is  the  tibia 
alone  which  receives  the  weight  of  the  body, 
and  transmits  it  to  the  astragalus.  This  fact 
should  be  carefully  borne  in  mind,  for  it  has 
considerable  influence  upon  the  accidents  so 
frequently  occurring  here.  The  astragalus,  from 
the  way  in  which  it  supports  the  body,  has  often 
been  compared  to  the  key-stone  of  an  arch,  the 
arch  being  represented  by  the  foot.  That  the 
foot  presents  an  arched  concavity  at  its  lower 
part  cannot  be  doubted ;  but  it  is  by  no  means 
so  certain  that  this  is  designed  upon  the  prin- 
ciple of  the  architectural  arch  to  support  the 
weight  of  the  body  :  in  fact,  the  astragalus, 
which  receives  the  entire  weight,  does  not  cor- 
respond to  the  centre  of  this  arch.  The  true 
design  of  the  vaulted  form  of  the  foot  is  to 
permit  its  accommodating  itself  to  the  several 
irregularities  of  surface  which,  both  in  standing 
and  progression,  it  must  encounter. 

The  motions  of  flexion  and  extension  are  the 
only  ones  permitted  at  the  ankle-joint.  In 
flexion  the  astragalus  rolls  from  before  back- 
wards in  the  tibio-fibular  mortise;  it  maybe 
continued  until  the  foot  and  leg  form  with 
each  other  an  angle  of  about  sixty  degrees ; 
at  this  point  further  flexion  is  prevented,  partly 
by  the  tension  of  the  middle  fibulo-tarsal  liga- 
ment, and  still  more  effectually  by  the  neck  of 
the  astragalus  coming  into  contact  with  the 
lower  edge  of  the  tibia.  In  flexion  the  anterior 
tibio-tarsal  and  fibulo-tarsal  ligaments  are  both 
relaxed ;  the  posterior  and  middle  fibulo-tarsal 
are  rendered  tense ;  the  internal  tibio-tarsal 
ligament  has  its  posterior  fibres  stretched  and 
its  anterior  ones  loosened.  2.  In  extension 
the  foot  not  only  returns  to  its  rectangular  posi- 
tion with  the  leg,  but  may  even  be  carried 
beyond  this,  so  as  to  form  with  the  tibia  an 
obtuse  angle  of  about  one  hundred  and  fifty 
degrees.*  Further  extension  is  at  this  point 
prevented  by  the  tension  of  the  ligaments  which 
lie  in  front,  and  also  by  the  astragalus  behind 
coming  into  contact  with  the  lower  edge  of  the 
tibia.  During  extension  the  astragalus  rotates 
forwards  in  the  tibio-fibular  mortise ;  the  pos- 
terior ligaments  are  relaxed,  the  anterior  are  put 
upon  the  stretch,  the  state  of  each  individual 
ligament  is,  in  short,  reversed  from  what  we 
have  just  described  as  its  condition  in  the 
opposite  motion  of  the  joint.  3.  A  slight  degree 
of  lateral  motion  of  the  ankle  is  perceptible  in 
the  dead  subject,  but  during  life  it  cannot  be 
said  to  exist :  hence,  in  the  classification  of 
Cloquet  and  Bichat,  the  joint  is  properly 
ranked  under  that  variety  of  ginglymus  to  which 
we  apply  the  term  "perfect." 

The  ankle  is  the  analogue  of  the  wrist-joint 
in  the  superior  extremity,  and  accordingly, 
though  there  are  certain  points  of  difference 
between  them,  the  general  character  of  both  is 

*  According  to  Hildebrandt  the  angle  of  flexion 
is  45°,  and  the  angle  of  extension  according  to 
Rosenthal  (Handb.  der  Chir.  Anat.)  is  175°.— ED. 


154 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


the  same.  It  is  no  less  interesting  than  instruc- 
tive to  contrast  these  two  articulations  with 
each  other,  for  in  doing  so  we  find  that  the 
modifications  of  structure  here,  as  well  as  in 
all  other  instances,  are  referable  to  the  peculiar 
function  which  each  part  is  destined  to  perform. 
The  hand  in  the  human  subject  is  exclusively 
an  organ  of  prehension  ;  the  foot  is  one  merely 
of  support : — now  this  simple  fact  at  once  fur- 
nishes us  with  a  clue  to  all  difficulties.  The 
great  strength  and  sudden  expansion  of  the 
tibia  and  fibula  at  the  ankle,  are  evidently  a 
provision  to  sustain  the  weight  of  the  body  and 
to  increase  the  basis  of  its  support;  in  the 
radius  and  ulna  such  size  and  strength  would 
have  been  to  no  purpose,  and  hence  these  bones 
at  the  wrist  are  comparatively  thin  and  delicate. 
At  the  ankle  we  should  naturally  have  expected 
frequent  dislocations,  owing  to  the  great  weight 
from  above,  and  to  the  great  mobility  which  for 
the  purposes  of  progression  must  at  the  same 
time  necessarily  exist  here  ;  these  are  two  most 
formidable  causes  of  displacement ;  but,  as  if  in 
compensation,  we  find  two  strong  buttresses  (the 
malleoli)  projecting  one  upon  either  side  of  the 
joint,  and  rendering  such  displacement,  under 
ordinary  circumstances,  almost  impossible.  At 
the  wrist,  where  there  is  no  weight  to  be  sup- 
ported, such  lateral  splints  would  have  been 
superfluous  :  hence  the  imperfect  and  almost 
rudimental  malleoli  of  the  radius  and  ulna; 
hence  the  shallow  and  imperfect  cavity  ; 
hence,  in  a  word,  the  anatomical  confor- 
mation which  constitutes  the  ankle-joint  a 
ginglymus,  and  the  wrist  an  arthrodia.  In 
the  motions  of  the  ankle  and  wrist-joints  we 
observe  likewise  a  striking  difference:  in  the 
former,  lateral  motion  would  have  been  super- 
flous  in  reference  to  the  function  of  the  foot ; 
at  the  wrist,  on  the  contrary,  a  free  lateral  mo- 
tion is  indispensable  to  increase  the  sphere  of 
action  of  the  hand. 

For  the  BIBLIOGRAPHY  of  this  article,  see  that 
of  ARTICULATION. 

(John  E.  Brenan.) 

ANKLE-JOINT,  ABNORMAL  CONDI- 
TION OF  THE.— The  deviations  from  the  na- 
tural or  normal  condition  of  the  ankle-joint  may 
be  classed  under  those  which  are  referable  to 
accident  and  to  disease :  any  defects  which 
may  be  considered  to  result  from  congenital 
malformation  shall  be  elsewere  treated  of. 
(See  FOOT.) 

Accidents. — The  different  structures  which 
immediately  compose  the  ankle-joint,  as  well 
as  those  which  surround  this  articulation,  and 
are  merely  accessary  to  its  functions,  are,  each 
and  all,  liable  to  numerous  accidents,  the  most 
important  of  which  we  shall  here  advert  to. 

These  accidents  may  affect  the  tendons,  the 
ligaments,  or  the  bones. 

Tendons. — Those  tendons  which  pass  behind 
the  inner  and  outer  malleoli  are  occasionally 
displaced  ;  and,  although  the  accident  must  be 
considered  a  rare  one,  it  ought  not  here  be 
overlooked. 


"  The  two  peronaei  extensor  muscles,"  says 
the  late  Mr.  Wilson,*  "  where  they  pass  behind 
and  below  the  fibula  over  a  smooth  lubricated 
surface  of  that  bone,  are  bound  to  it  by  a  strong 
ligament ;  but  should  the  ligament  give  way, 
one  or  both  of  these  tendons  may  escape  from 
the  groove  or  pulley  in  which  they  usually  play, 
and  being  thrown  forwards  over  the  edge  of 
the  bone,  in  this  new  situation  their  action  on 
the  foot  will  be  to  bend  it  on  the  leg,  when  in 
their  natural  position  it  was  to  extend  it.  The 
peronsei  having  been  habituated  to  act  with  the 
extensor  muscles,  continue  to  contract  at  the 
same  time  with  them,  but  now  they  oppose 
the  effect  which  formerly  in  conjunction  with 
the  extensor  muscles  they  produced  upon  the 
foot,  and  by  so  doing  excite  much  pain  and 
irritation  in  addition  to  the  lameness.  When 
this  situation  of  the  tendon  is  discovered  early, 
the  tendon  can  be  readily  restored  to  its  proper 
place,  but  if  this  is  not  done,  it  forms  a  new 
groove  on  the  fore  part  of  the  bone,  and  the 
old  one  is  filled  up,  or  otherwise  so  altered 
that  it  cannot  receive  the  tendon,  and  thus  the 
pain  and  lameness  may  continue  for  life. 
I  have  seen  this  occurrence  sometimes  in  the 
living  body  early  enough  to  return  the  tendon, 
and  have  been  consulted  in  cases  where  it 
could  not  be  returned ;  in  one,  where  the  pain 
was  so  violent  that  I  recommended  the  divi- 
sion and  removal  of  part  of  the  tendon ;  the 
muscle  then  contracted  to  its  full  extent,  and 
afterwards  shrunk,  and  no  inconvenience  was 
felt  after  the  operation.  I  have  met  with  two 
or  three  instances  of  this  kind  of  displacement 
of  tendons  in  bodies  brought  into  the  dissect- 
ing-room ;  but  of  the  previous  history  of  the 
cases  I  could  know  nothing."  Mr.  Wilson 
adds,  "  Those  tendons  which  pass  in  grooves 
behind  the  inner  ankle  are  liable  to  a  similar 
displacement.''  Of  the  latter  accident  we  have 
known  but  one  instance,  but  of  the  former 
several. 

Ligaments.  —  Accurate  anatomical  investi- 
gations of  the  actual  condition  of  the  various 
structures  which  compose  the  ankle-joint, 
when  affected  by  a  sprain,  have  shown  that 
in  slight  cases  of  sprain  of  this  joint  no- 
thing unnatural  has  been  discovered,  as  the 
bonds  of  union  between  the  bones  have  been 
merely  stretched  or  strained.  In  others  more 
severe,  the  ligaments  have  been  found  broken 
or  torn  from  their  attachment  to  the  bones, 
the  synovial  sac  opened,  and  its  fluid  to  have 
escaped  from  the  cavity  of  the  joint ;  the  cel- 
lular tissue  around  has  been  filled  with  extrava- 
sated  blood,  and  with  synovial  and  serous  fluids. 
In  these  cases  the  nerves,  bloodvessels,  ten- 
dons, even  the  skin  itself,  have  been  subjected 
to  a  degree  of  stretching  and  extension,  more 
or  less  considerable.  Baron  Dupuytren,  from  nu- 
merous observations  on  the  living  subject,  from 
post-mortem  examinations,  and  experiments,  is 
of  opinion  that  a  slight  accidental  torsion  of  the 
foot  inwards  or  outwards,  amounting  to  a 
sprain,  only  produces  an  injury,  in  which 

*  Wilson's  Lectures  on  the  Bones,  &c. 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


155 


the  ligaments  are  merely  stretched  ;  but  that  a 
greater  effort  produces  a  separation  of  the 
lateral  ligament  from  one  or  other  of  the  mal- 
leoli  by  laceration  of  its  compact  tissue,  or  of 
the  periosteum  which  covers  it,  while  the  liga- 
ments themselves  remain  unbroken.  Oppor- 
tunities do  not  often  occur  of  discovering 
the  effects  of  sprains  on  the  joints  by  anato- 
mical examination  made  at  various  periods 
after  the  accident ;  but  although  Dupuytren's 
opinion  may  be  correct  as  to  the  majority  of 
cases,  still  others  have  found  the  lateral  liga- 
ments ruptured  across,  instead  of  having  been 
torn  from  the  bone.  Mr.  Wilson  found,  in 
a  case  where  the  patient  died  five  days  after 
a  severe  sprain  of  the  ankle-joint,  that  the  del- 
toid ligament  binding  the  tibia  to  the  foot  was 
lacerated,  and  that  the  synovial  membrane  of 
the  ankle-joint  was  also  much  torn.  In  older 
cases  he  found  evidences  of  chronic  inflamma- 
tion in  the  ligamentous  structures  around  the 
joint ;  that  these  structures  were  thickened 
and  vascular,  and  had  lost  much  of  their  plia- 
bility. 

The  pain  and  inability  to  walk,  the  sudden 
effusion  around  the  injured  ankle,  the  ecchy- 
mosis,  tenderness  of  the  skin  and  tension, 
the  signs  of  this  injury  expressed  by  the  living 
structures,  are  all  accounted  for  by  the  lesions 
which  an  anatomical  examination  of  these  in- 
juries of  the  ankle-joint  discovers.  This  also 
explains  what  practical  writers  have  noted  of 
sprains,  viz.  that  sometimes  the  ankle-joint 
which  has  been  affected  by  this  accident, 
rapidly  and  perfectly  recovers, — that,  on  the 
other  hand,  it  is  not  unfrequently  so  weakened 
by  the  injury,  as  to  become  peculiarly  suscep- 
tible of  a  renewal  of  the  sprain  from  slight 
causes ;  sometimes  the  articulation  contracts  a 
rigidity,  by  which  for  a  time,  or  even  for  life 
itself,  its  proper  functions  are  interfered  with, 
and  a  permanent  osdema  of  the  soft  parts 
around  the  joint  is  too  often  in  these  cases 
established. 

Bones.  —  The  bones  which  contribute  to 
form  the  ankle-joint  are  liable  to  fracture  and 
to  luxation.  These  bones,  we  know,  are  the 
tibia,  fibula,  and  astragalus ;  for  an-  account  of 
the  accidents  which  affect  the  latter  particularly, 
we  refer  to  the  article  FOOT,  and  shall  here, 
as  succinctly  as  we  can,  notice  the  various  dis- 
placements of  the  bones  of  the  leg  at  the 
ankle-joint,  which  have  been  observed  to  be 
the  result  of  a  fracture  through  one  or  both 
of  the  malleoli,  or  of  an  accidental  rupture  of 
the  ligaments  which  tie  these  eminences  to  the 
foot. 

When  we  reflect  on  the  great  strength  of  the 
ligaments  which  connect  the  astragalus  to  the 
tibia  and  fibula,  and  the  support  which  the  ar- 
ticulation derives  from  the  prolongation  down- 
wards of  the  malleoli,  we  can  easily  perceive 
that  a  luxation  of  the  foot  must  be  the  effect 
only  of  some  very  violent  cause,  and  that  this 
accident  can  very  rarely  (in  a  true  sense)  be  a 
simple  one.  Effusions  of  blood,  rupture  of  all 
the  surrounding  ligaments,  fracture  of  the 
external  or  even  of  both  the  malleoli,  wounds 
of  the  soft  parts,  and  even  protrusion  of  the 


bones,  are  contingences  which  frequently  render 
the  dislocation  of  the  tibia  at  the  ankle-joint 
a  very  complex  accident. 

The  most  superficial  view  of  the  structure 
of  the  ankle-joint  will  convince  any  one  that 
no  lateral  displacement  of  the  bones  of  the 
leg  can  occur,  without  its  having  been  im- 
mediately preceded  by  a  fracture  of  either  the 
tibial  or  peronaeal  malleolus  ;  but  such  a  view 
would  warrant  the  conjecture,  that  a  luxation 
in  the  direction  forwards  or  backwards  may 
possibly  take  place,  simply  from  the  rupture 
of  the  ligaments  of  the  joint  alone,  and  the 
action  of  muscles.  Such  a  luxation  as  this 
last,  when  no  fracture  exists,  should  be  best 
entitled  to  the  name  of  simple ;  yet  those 
luxations  of  this  articulation  (such  is  the 
vagueness  of  surgical  language),  whether  ac- 
companied with  fracture  or  not,  are  all  called 
simple,  provided  there  be  no  wound  through 
the  integuments  communicating  with  the  cavity 
of  the  joint.  In  this  latter  case  alone  the 
luxation  is  denominated  compound,  of  which 
it  is  not  our  intention  here  to  treat. 

WTe  shall  arrange  the  luxations  of  the  bones 
of  the  leg  at  the  ankle-joint  in  the  above  sense 
called  simple  luxations,  into  those  which  occur 
in  the  direction  inwards,  outwards,  forwards, 
and  backwards,  and  each  of  these,  it  is  be- 
lieved, may  be  a  partial  or  a  complete  lux- 
ation. 

Luxation  of  the  Tibia  inwards. — This  luxa- 
tion may  be  complete  or  incomplete  :  we 
shall  first  treat  of  the  most  common  form  of  it 
or  that  termed  partial  Dislocation  of  the  Tibia 
inwards  from  the  Astragalus,  or  Pott's  luxation. 
Mr.  Pott,  in  describing  this  accident,  observes, 
"  that  the  support  of  the  body,  and  the  due 
and  proper  use  and  execution  of  the  office  of 
the  joint  of  the  ankle,  depend  almost  entirely 
on  the  perpendicular  bearing  of  the  tibia  upon 
the  astragalus,  and  on  its  firm  connexion  with 
the  fibula.  If  the  former  bone  is  forced  from 
its  just  and  perpendicular  position  on  the 
astragalus ;  or,  if  it  be  separated  by  violence 
from  its  connexion  with  the  latter,  the  joint  of 
the  ankle  will  suffer  a  partial  luxation  inter- 
nally :  this  is  the  case  when,  by  leaping  or 
jumping,  the  fibula  breaks  in  its  weak  part, 
within  two  or  three  inches  of  its  lower  ex- 
tremity. When  this  happens,  the  inferior  frac- 
tured end  of  the  fibula  falls  inwards  towards 
the  tibia,  that  extremity  of  the  bone  which 
forms  the  outer  ankle  is  turned  somewhat  out- 
wards and  upwards,  and  the  tibia,  having  lost  its 
proper  support,  and  not  being  of  itself  capable 
of  steadily  preserving  its  true  perpendicular 
bearing,  is  forced  off  from  the  astragalus,  in- 
wards, by  which  the  ligaments  are  torn,  thus 
producing  a  perfect  fracture  and  a  partial  dis- 
location."* 

If  we  are  called  to  examine  a  patient  who 
has  recently  suffered  this  accident,  we  find  that 
the  ankle-joint  now  possesses  some  degree 
of  lateral  mobility.  In  the  normal  state  of  the 
ankle-joint  we  know  that  the  quadrilateral 
cavity  formed  by  the  tibia  and  fibula  for  the 

*  Pott's  Works  by  Earle,  vol.  i.  p.  327. 


156 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


reception  of  the  astragalus,  makes  with  the 
latter  a  perfect  mortise  joint,  which  admits 
of  motions  of  flexion  and  extension,  but 
allows  of  no  motion  whatever  laterally  or 
horizontally;  for  it  must  be  recollected  that 
those  motions  of  inclination  of  the  foot,  known 
under  the  names  of  adduction  and  abduction, 
are  not  movements  in  the  ankle-joint,  but  take 
place  in  the  joints  of  the  tarsus :  but  the  un- 
natural mobility  in  question  is  very  great  when 
the  fibula  is  broken  at  its  lower  part;  this  is 
shewn,  when,  after  the  surgeon  has  bent  the  limb 
to  relax  the  muscles,  the  leg  is  fixed  by  one 
hand  placed  at  its  lower  extremity,  whilst  the 
other  moves  the  foot  from  within  outwards; 
the  foot  is  then  seen  to  move  in  a  transverse 
line  and  to  quit  the  axis  of  the  leg ;  the  mal- 
leolus  internus  projects  inwards,  and  the  mal- 
leolus  externus  is  moved  upwards  and  out- 
wards, and  all  these  appearances  vanish,  when 
by  a  contrary  movement  we  bring  the  foot  to 
its  natural  position. 

When  we  le,ave  the  limb  for  a  moment  to 
itself,  we  notice  that  there  is  a  remarkable 
change  in  the  point  of  incidence  of  the  axis 
of  the  leg  upon  the  foot.  The  tibia  and  upper 
fragment  of  the  fibula,  although  really  remain- 
ing in  their  natural  position,  appear  driven  in- 
wards, while  the  foot  is  rotated  outwards. 

The  changes  of  direction  of  the  leg  and  foot 
are  such,  that  if  the  axis  of  the  leg  were  pro- 
longed inferiorly,  instead  of  falling  on  the 
astragalus,  it  would  leave  this  bone,  and  con- 
sequently the  whole  foot,  more  or  less  on  its 
outer  side;  hence  the  impossibility  patients 
experience  of  bearing  upon  the  foot  ,  which 
only  presents  its  inner  edge  to  the  ground. 


Fig.  51. 


Fig.  52. 


Partial  luxation  of  the  Tibia  inwards,  or  Pott's 
luxation. 


This  change  is  a  necessary  and  constant  effect 
of  the  displacement  of  the  foot,  when  the 
fibula  ceases  to  support  it  on  the  outer  side, 
arid  when  the  peronsei  muscles  begin  to  con- 
tract. The  foot  and  external  malleolus  which 
make  part  of  one  system,  move  in  one  direc- 
tion ;  the  tibia  and  upper  fragment  of  the  fibula 
move,  or,  to  speak  perhaps  more  correctly, 
remain,  in  another.  The  centre  of  this  new 
motion  is  no  longer  in  the  articulation,  but, 
in  an  oblique  line,  passing  through  the  joint, 
and  extending  from  the  malleolus  internus  to 
the  point  of  fracture  of  the  fibula:  this  line  is 
well  expressed  in  Jig.  51,  representing  the  frac- 
ture of  the  fibula,  and  taken  from  the  engrav- 
ing which  accompanies  the  work  of  Pott. 

The  retiring  angle  seen  (fig.5\,  52,  a)  in  this 
partial  luxation  of  the  tibia  inwards,  on  the 
outer  part  of  the  articulation,  and  the  pro- 
jecting one  (b)  existing  at  the  inner,  consti- 
tute the  most  striking  features  of  the  accident ; 
these  angles  correspond  exactly  to  the  extremi- 
ties of  the  line  above-mentioned,  in  the  direc- 
tion of  which  the  weight  of  the  body  acts,  when 
the  foot  being  turned  outwards  this  line  may 
be  seen  to  traverse  the  leg  obliquely  from  the 
lower  part  of  the  upper  fragment  of  the  broken 
fibula  to  the  malleolus  internus. 

We  cannot  omit  to  notice  also,  that  there  is 
in  all  these  cases  a  remarkable  rotation  of  the 
whole  foot  on  its  long  axis,  in  such  a  direction 
that  the  upper  surface  of  the  astragalus  looks 
obliquely  upwards  and  inwards,  f/g.52,cj  the 
inner  edge  of  the  foot  is  turned  downwards, 
the  sole  inclined  outwards,  the  outer  edge 
raised,  and  the  dorsum  turned  directly  upwards. 
The  extent  of  this  rotatory  motion  is  besides 
always  proportioned  to  the  displacement  out- 
wards ;  both  are  attributable  to  the  same  causes, 
viz.  the  weight  of  the  body,  and  the  action  of 
the  peronaei  muscles,  when  the  patient  has  at- 
tempted to  walk  after  the  fracture  has  occurred. 

It  is  on  these  combined  movements  when 
not  corrected  by  a  proper  mode  of  treatment, 
that  the  deformity  of  the  foot,  and  all  the 
consequent  difficulties  in  walking,  depend. 

Complete  luxation  of  the  tibia  inwards  from 
the  astragalus,  complicated  with  a  simple  frac- 
ture of  the  fibula. — This  is  a  very  severe,  and, 
fortunately,  a  very  rare  accident.  In  alluding 
to  it,  Dupuytren  says,*  that  "  the  foot  is  not 
only  susceptible  of  being  carried  outwards,  but 
also  upwards  at  the  same  time;"  a  double 
displacement,  which  he  had  observed  to  occur 
only  once  in  200  cases  of  fractures  of  the 
fibula  treated  in  the  Hotel  Dieu  for  fifteen 
years,  "  but  the  case  was  so  marked,"  he  says, 
"  that  in  future  it  cannot  be  mistaken  or  passed 
over  in  silence."  It  cannot  occur  unless  the 
fibula  is  fractured ;  for  this  condition  is  indis- 
pensable to  any  displacement  of  the  foot  in- 
wards or  outwards ;  it  requires  besides  a  com- 
plete laceration  of  the  short  thick  ligaments 
placed  between  the  tibia  and  fibula,  the  strength 
of  which  is  such  that,  in  most  experiments  on 

*  Sur  la  Fract.  de  1'Extremite  inferieure  du  Pe- 
rone,  in  Annuaire  Med.  Chir.  des  Hopitaux  de 
Paris,  1809,  4to.  and  folio. 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


157 


the  dead  subject,  they  resist  more  powerfully 
than  the  structure  of  the  bones  themselves. 

It  was  as  a  consequence  of  the  fracture  of 
the  fibula  and  a  rupture  of  these  ligaments, 
that,  in  the  case  alluded  to,  the  astragalus  was 
seen  dislocated  outwards,  and  then  drawn  up 
on  the  outer  side  of  the  tibia.  In  short,  the 
astragalus,  the  malleolus  externus,  and  the  foot, 
which  formed  but  one  system  of  parts  firmly 
connected,  were  drawn  first  to  the  outer  side  of 
the  leg,  and  then  two  inches  upwards  on  the 
tibia. 

A  carpenter,  aged  fifty-four  years,  was  ad- 
mitted into  the  Hotel  Dieu,  in  February,  1816. 
His  right  leg  presented  all  the  signs  of  fracture 
of  the  fibula  at  its  inferior  part,  such  as  devia- 
tion and  rotation  of  the  foot  outwards,  promi- 
nence of  the  tibia,  and  of  the  internal  malleolus 
inwards,  depression  and  crepitation  above  the 
outer  ankle ;  but  that  which  most  attracted  the 
attention  was,  1st,  the  shortening  of  the  limb, 
and,  2dly,  the  enormous  increase  in  breadth  of 
the  space  which  should  naturally  intervene  be- 
tween the  two  malleoli.  The  sinking  down  of 
the  lowest  part  of  the  tibia,  even  to  the  level  of 
the  sole  of  the  foot,  where  the  projection  of  the 
internal  malleolus  could  be  felt,  the  elevation  of 
the  astragalus,  of  the  peroneal  malleolus,  and  the 
whole  of  the  foot  along  the  external  surface  of 
the  tibia,  even  to  two  inches,  were  all  symp- 
toms quite  unusual  in  fracture  of  the  fibula, 
and  left  no  doubt  that  the  ligaments  which 
stretched  inferiorly  from  this  bone  to  the  tibia 
had  been  lacerated,  and  that  the  foot,  yielding 
to  a  violent  effort  from  within  outwards,  and 
from  below  upwards,  had  been  luxated  in  these 
directions,  and  had  carried  with  it  the  peroneal 
malleolus.  This  then  is  evidently  a  case  of 
complete  dislocation  of  the  tibia  inwards,  or, 
as  the  French  writers  would  call  it,  a  luxation 
of  the  foot  outwards  and  upwards. 

Although  this  species  of  luxation  has  not 
been  specially  described  in  any  of  our  English 
works,  I  doubt  not  but  such  an  accident  has 
been  observed,  although  it  is  possible  that  its 
nature  was  not  always  clearly  understood.  Sir 
A.  Cooper,  in  his  valuable  work  on  Disloca- 
tions and  Fractures,  states  that  the  foot  has  also 
been  known  to  be  thrown  upwards,  between 
the  tibia  and  fibula,  by  the  giving  way  of  the 
ligament  which  unites  these  bones;  but  he 
adds  that  this  accident  is  only  an  aggravated 
form  of  an  internal  dislocation. 

We  find  but  little  difficulty  in  comprehend- 
ing how  the  accident  described  by  Dupuytren 
may  occur,  because,  the  fibula  having  been 
first  fractured,  the  broken  bone  and  ruptured 
ligaments  permit  the  foot  to  yield  to  the 
powerful  action  of  the  muscles  on  the  back 
part  and  outside  of  the  leg,  which  draw  it  at 
first  outwards,  and  then  upwards ;  but  on  the 
contrary,  it  is  not  easy  to  imagine  any  force 
capable  of  overcoming  the  resistance  of  the 
many  inter-osseous  ligaments  which  exist,  and 
of  the  fasciae  and  annular  membranes  which 
surround  the  bones  of  the  leg :  a  force  must  be 
great  indeed  which  can  overcome  the  muscles 
also,  and  cause  a  divarication  of  the  bones  of  the 
leg  sufficient  to  permit  the  astragalus  and  rest 


Fig.  53. 


Fig.  54. 


Complete  luxation  of  tlie 
tibia  inwards  or  of  the  foot 
outwards  and  upwards. — 
(Dupuytren.) 


Dissection  of  a  case  of 
the  same  class  as  fig.  53, 
from  the  museum  of  St. 
Thomas's  Hospital. 


of  the  foot  to  be  thrown  upwards  between  the 
tibia  and  fibula.  Supposing  this  last  case  pos- 
sible, the  shortening  of  the  limb  and  its  newly- 
acquired  breadth  between  the  malleoli  might 
lead  to  error,  and  the  two  cases  here  alluded  to 
be  at  first  sight  confounded ;  but  in  Dupuy- 
tren's  case,  the  fracture  of  the  fibula,  the  over- 
lapping of  its  fragments,  and  above  all  the 
ascent  of  the  external  malleolus,  so  much  above 
the  level  of  the  internal,  will  always  constitute 
such  characteristic  marks,  that  when  such  an 
accident  presents  itself,  we  conceive  it  cannot 
be  confounded  with  any  other  injury  of  this 
articulation. 

What  are  the  anatomical  characters  of  this 
complete  luxation  of  the  tibia  inwards,  with 
displacement  of  the  foot  and  outer  malleolus 
upwards  and  outwards?  It  is  evident  that 
there  must  be  very  extensive  injury  done  in 
such  cases  to  the  ligaments  and  bones ;  the  fibula 
must  be  fractured  near  the  ankle,  and  it  is 
probable  that  some  fragments  of  the  tibia  may 
be  carried  off  with  the  fibula,  for  such  is  the 
strength  of  the  ligaments  between  the  lower  part 
of  the  tibia  and  fibula,  where  these  unite  for 
the  reception  of  the  astragal  us  (vid.fg.  61),  that 
there  is  reason  to  believe  that  the  bone  itself 
would  break  before  the  ligaments  would  yield. 
If  a  portion  of  the  tibia,  however,  is  not  broken 
off  and  carried  with  the  fibula,  these  transverse 
fibrous  bands  must  be  torn,  as  well  as  those 


158 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


oblique  ligaments  which  pass  before  and  be- 
hind from  the  fibula  to  the  tibia.  The  proper 
interosseous  membrane  itself  must  be  detached 
from  between  the  bones  to  allow  the  astragalus 
to  ascend  along  the  outside  of  the  tibia.  While 
the  ligaments  which  connect  the  outer  malleolus 
to  the  tibia  must  be  torn,  those  which  unite  it 
to  the  foot  remain  entire,  the  deltoid  or  internal 
lateral  ligament  must  be  completely  torn  across, 
as  well  as  the  synovial  sac  of  the  articula- 
tion ;  nor  should  it  be  forgotten  that  the  annu- 
lar ligaments  and  strong  fasciae  at  the  lower 
part  of  the  leg,  must,  in  so  severe  and  ex- 
tensive an  injury,  be  lacerated;  the  tendons, 
muscles,  and  other  structures  may  escape  injury, 
the  astragalus  and  outer  malleolus  are  dragged 
up  (fg.  54,  a,  6),  their  ascent  being  only  limited 
by  the  lower  point  of  the  upper  fragment  of 
the  fibula  (c),  which  remains  in  its  natural 
relation  to  the  tibia,  except  that  it  must  be 
somewhat  approximated  to  it ;  the  lowest  point 
of  the  superior  fragment  of  the  broken  fibula 
rest  upon  the  summit  of  the  articular  pulley  of 
the  astragalus,  as  is  well  seen  in  a  preparation 

B'eserved  in  the  collection  of  St.  Thomas's 
ospital  Museum,  the  delineation  of  which  we 
have  borrowed  from  Sir  A.  Cooper's  work.  The 
preservation  of  this  specimen,  which  in  our 
mind  is  a  true  example  of  the  complete  dislo- 
cation of  the  tibia  inwards,  and  of  the  external 
malleolus  astragalus  and  foot  upwards  and 
outwards,  is  a  new  proof  of  the  truth  of  the 
observation  we  have  above  made,  that  this 
severe  accident  had  not  altogether  escaped  the 
notice  of  English  surgeons,  although  the 
11  Annuaire"  contains  the  first  accurate  account 
of  the  external  signs  by  which  it  may  be  recog- 
nized in  the  living  subject. 

Luxation  of  the  tibia  outwards,  complicated 
with  simple  fracture  of  one  or  both  of  the  mal- 
leoli. — This,  it  is  said,  is  one  of  the  most  dan- 
gerous of  the  dislocations  to  which  the  ankle  is 
liable,  for  its  production  has  been  noticed  to 
be  attended  with  greater  violence,  and  to  be 
accompanied  by  more  contusion  of  the  integu- 
ments, more  laceration  of  ligaments,  and  greater 
injury  to  bone,  than  we  have  occasion  to  ob- 
serve in  the  production  of  the  other  luxations 
of  this  joint. 

The  astragalus  in  this  accident  is  carried  towards 
and  below  the  external  malleolus(7zg.  55),  whilst 
the  outer  edge  of  the  foot  is  turned  downwards, 
its  inner  edge  upwards,  and  the  sole  inwards, 
the  tibial  malleolus  disappears,  and  is  hidden 
at  the  bottom  of  a  retiring  angle  formed  by  the 
inner  side  of  the  leg  and  foot,  and  the  peroneal 
malleolus  forms,  with  the  astragalus,  a  salient 
angle  rounded  off  on  the  outside.  Looking 
only  to  the  change  of  form,  situation,  and  rela- 
tive position  of  the  leg  and  foot,  we  might  sup- 
pose the  case  one  of  congenital  club-foot.*  The 
luxation  of  the  tibia  outwards,  with  inversion 
of  the  sole  of  the  foot,  is  one  of  the  most  rare 
and  most  difficult  cases  to  explain.  Its  pro- 
duction must  be  the  result,  we  suppose,  of  co- 
incidences rare  and  unusual.  There  may  be  a 
certain  obliquity  in  the  line  of  direction  of  the 

*  Dupuytren,  Annuaire. 


Fig.  55. 


Fig.  56. 


Luxation  outwards  of  the         Dissection  of  the  luxa- 
tibia  and  fibula   with   ob-     tion  outwards  (Museum 
lique  fracture  of  the  tibia.      of  St.  Thomas's    Hospi- 
tal}.    [Fty.55.] 

fracture  coinciding  with  a  considerable  degree 
of  resistance  in  the  lower  fragment  of  the  fibula : 
thus,  if  we  can  suppose  that  a  fracture  shall 
traverse  the  tibia  obliquely  from  above  down- 
wards, and  from  within  outwards,  so  that  the 
point  of  the  upper  fragment  be  directed  down- 
wards and  outwards,  and  the  lower  fragment  point 
upwards  and  inwards,  and  if  to  this  obliquity 
we  suppose  added  a  certain  resistance  on  the 
side  of  the  lower  fragment  of  the  fibula,  it  is 
plain  that  the  foot  being  unable  to  turn  out- 
wards, must  be  carried  inwards  by  the  action 
of  the  muscles,  and  with  this  inversion,  &c. 
some  little  shortening  of  the  limb,  at  least 
when  measured  on  its  inner  side,  may  be  ex- 
pected. 

If  this  accident  be  neglected,  the  cure  which 
nature  attempts  is  very  imperfect,  the  ankle-joint 
becomes  stiff  and  rigid  (fg.  56),  the  interval  be- 
tween the  internal  and  external  malleolus  is 
much  increased^  the  latter  presses  heavily 
against  the  integuments,  which,  when  the  limb 
is  much  exercised,  have  a  strong  tendency  to 
inflame  and  suppurate,  the  outer  edge  of  the 
foot  throughout  its  whole  line  presses  the 
ground,  whether  the  patient  be  standing  or 
walking,  while  the  inner  edge  is  somewhat 
elevated  and  curved  inwards.  In  the  dissec- 
tion of  this  accident,  it  will  be  found  that  the 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


159 


malleolus  interims  is  fractured,  and  in  general, 
we  suppose,  with  the  obliquity  from  above 
downwards,  and  within  outwards,  above  de- 
scribed. The  deltoid  ligament  remains  un- 
broken, the  capsular  membrane  is  torn  in  front, 
the  fibula  has  been  found  obliquely  fractured, 
as  well  as  the  tibia,  or  the  three  ligaments 
which  connect  it  to  the  tarsus  have  given  way; 
none  of  the  tendons  suffer,  and  haemorrhage  to 
any  extent  in  these  cases  seldom  or  never  occurs, 
as  the  large  arteries  generally  escape  injury. 

Luxation  of  the  tibia  and  fibula  forwards, 
and  also  luxation  of  these  bones  backwards  from 
the  articular  pulley  of  the  astragalus,  without 
fracture. — In  the  simple  and  complete  luxa- 
tion of  the  bones  of  the  leg  forwards  at  the 
ankle-joint,  (without  fracture,)  the  articular 
pulley  of  the  astragalus  is  placed  behind  the 
inferior  extremity  of  the  tibia,  which  last  rests 
partly  on  the  superior  surface  of  the  neck  of 
the  astragalus,  and  partly  on  the  os  naviculare. 

In  the  simple  and  complete  luxation  of  the 
tibia  backwards,  (without  fracture,)  the  inferior 
extremity  of  the  tibia  is  placed  behind  the  arti- 
cular pulley  of  the  astragalus,  and  corresponds 
to  the  posterior  part  of  the  superior  surface  of 
the  os  calcis.  In  both  these  luxations,  the  na- 
tural connexion  with  each  other  of  the  bones  of 
the  leg  remains  undisturbed,  and  the  two  mal- 
leoli  advance  or  recede  together,  according  to 
the  direction  in  which  the  displacement  has 
occurred.  In  both,  the  capsular  membrane  and 
the  posterior  and  lateral  ligaments  must  be  ex- 
tensively lacerated,  and  most  of  the  flexor  and 
extensor  tendons,  in  some  degree,  put  upon  the 
stretch. 

The  luxation  of  the  bones  of  the  leg  forwards 
cannot  take  place,  but  in  a  forced  and  sudden 
extension  of  the  leg  on  the  foot,  when  the  latter 
being  retained  by  some  obstacle,  and  solidly 
supported,  we  fall  backwards. 

The  luxation  of  the  tibia  backwards,  on  the 
contrary,  cannot  happen  unless  when  the  foot 
is  strongly  flexed,  the  toes  being  elevated  and 
retained  in  this  position,  we  fall  forwards. 

Authors  have  seldom  failed  to  notice  these 
simple  luxations  forwards  and  backwards  of 
the  bones  of  the  leg,  yet  for  our  part,  no  mat- 
ter to  what  source  we  apply  for  information, 
we  cannot  satisfy  our  minds  that  we  can  adduce 
a  single  well-marked  example  of  luxation  of 
the  bones  of  the  leg  at  the  ankle-joint,  unac- 
companied by  a  fracture  of  one  or  both  of  the 
malleoli ;  we  would  not,  however,  be  under- 
stood to  deny  the  possibility  of  such  an  occur- 
rence, but  merely  to  state  our  conviction  that 
such  an  accident  must  be  exceedingly  rare. 

We  have  now  to  consider  luxations  of  the 
tibia  from  the  astragalus,  forwards  and  back- 
wards, when  complicated  with  a  simple  frac- 
ture of  the  fibula  or  tibia  close  to  the  articula- 
tion :  these  may  be  complete  or  partial. 

Complete  luxation  of  the  tibia  forwards  from 
the  articular  part  of  the  astragalus  compli- 
cated with  a  simple  fracture  of  the  fibula. — 
This  accident  may  arise  from  the  same  causes 
nearly  as  those  which  may  be  supposed  to 
influence  the  more  simple  luxation  in  the  same 
direction;  and  as  we  know  that  when  the 


fibula  is  fractured  near  its  malleolus,  the  pe- 
ronaei  muscles  may  under  certain  circumstances 
effect  a  luxation  of  the  tibia  inwards,  so  that 
displacement  which  we  are  now  considering 
may  be  the  result  of  the  action  of  the  gastro- 
cnemius  and  solaeus.  These  acting  on  the  foot, 
which  in  consequence  of  the  fracture  is  no 
longer  fixed  by  the  malleolus  externus,  cause 
the  astragalus  to  slip  from  before  backwards, 
and  the  lower  end  of  the  tibia  forwards,  and 
move  the  lower  fragment  of  the  fibula  in  such 
a  manner  that  its  malleolar  extremity  is  carried 
backwards,  and  the  upper  part  forwards.  This 
action  of  these  muscles,  however,  only  pro- 
duces a  very  incomplete  dislocation  whenever 
the  internal  malleolus  is  uninjured,  or  the  foot 
in  this  case  being  carried  outwards  and  back- 
wards at  the  same  time;  but  when,  as  often 
happens,  either  the  internal  malleolus  or  del- 
toid ligament  is  broken,  this  displacement  may 
be  as  complete  and  direct  as  the  simple  dis- 
location forwards  of  the  tibia.  We  then  find  the 
foot  lengthened  behind  and  shortened  in  front ; 
a  semicircular  excavation  occurs  in  the  former 
direction,  and  an  osseous  tumour  raises  the 
tendons  and  ligaments  on  the  front  of  the 
ankle,  but  it  is  to  be  particularly  remarked 
that,  whilst  in  the  simplest  form  of  luxation 
of  the  tibia,  i.  e.  where  there  is  no  fracture, 
the  external  malleolus  follows  the  tibia  and 
fibula,  and  forms  a  projection  corresponding 
to  that  of  the  internal,  it  is  in  this  case 
dragged  backwards  with  the  foot  to  which  it 
is  attached  by  the  lateral  ligaments,  and  no 
longer  has  the  same  direction  as  the  bones  of 
the  leg. 

In  the  dislocation  forwards  of  the  tibia 
(whether  simple  or  complicated  with  a  frac- 
ture of  the  fibula)  from  the  astragalus,  the 
articular  pulley  of  this  bone  is  placed  behind 
the  inferior  articular  cavity  formed  for  it  in  the 
tibia ;  but  this  latter  bone  at  the  same  time, 
it  will  be  recollected,  must  now  rest  on  the  dor- 
sum  of  the  tarsus,  where  it  is  formed  by  the  upper 
part  of  the  neck  of  the  astragalus  and  os  navi- 
culare. When  the  tibia  has  thus  once  advanced 
before  the  articular  pulley  of  the  astragalus,  the 
luxation  forwards  is  as  complete  as  it  well  can 
be ;  in  our  opinion,  to  imagine  any  more  com- 
plete luxation  of  the  tibia  forwards,  we  should 
be  obliged  to  presume  that  this  bone  in  its 
advance  on  the  dorsum  of  the  foot  had  com- 
pletely cleared  the  astragalus,  and  then  rested 
"  on  the  os  naviculare  and  os  cuneiforme  in- 
ternum"  *  which  last  form  part  of  the  anterior 

*  The  weight  that  so  justly  attaches  to  any  ob- 
servations from  Sir  A.  Cooper,  induced  us  to  con- 
sider well  the  account  he  gives  of  the  dissection  of 
this  complete  luxation  of  the  tibia  forwards,  in  his 
work  on  Dislocations  and  Fractures ;  and  we  find 
that  we  cannot  reconcile  it  with  our  ideas  of  the 
anatomy  of  the  injury.  We  are  sorry  in  this  in- 
stance to  be  obliged  to  differ  from  an  authority, 
to  which  we  feel  indebted  for  many  observation^ 
copied  into  these  pages  ;  but  we  think  there  must 
be  error  in  the  following  passage  taken  from  the 
valuable  work  to  which  we  allude,  page  178,  8th 
edition. 

"  On  dissection,  the  tibia  is  found  to  rest  upon 
the  upper  surface  of  the  os  naviculare  and  os  cunei- 


160 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


range  of  the  tarsus,  a  situation  which  the  tibia 
could  not  well  occupy,  without  a  previous 
lesion  of  the  tendons  of  the  tibialis  anticus, 
and  stretching  of  the  other  extensors :  from 
such  a  relative  position  of  the  bones  of  the  leg 
and  foot  would  result  a  shortening  of  the  dorsum 
of  the  foot  and  an  elongation  of  the  heel  to  an 
extent  which,  we  believe,  has  never  been  no- 
ticed. 

Partial  luxation  of  the  tibia  forwards,  with 
simple  fracture  of  one  or  both  of  the  malleoli. 
— The  complete  'luxation  forwards  of  the  tibia 
from  the  astragalus,  which  we  have  described 
in  the  preceding  section,  all  writers  look  upon 
as  the  more  common  form  of  dislocation  for- 
wards ;  while  the  partial  luxation  in  this  di- 
rection is  considered  a  rare  accident.  My 
opinion  upon  this  subject  is  quite  different; 
for  some  experience  in  these  accidents  leads 
me  to  say,  that  a  complete  luxation  of  the  tibia 
forwards  from  the  articular  pulley  of  the  astra- 
galus is  rare,  but  that  a  partial  luxation  in  this 
direction  accompanied  with  a  simple  fracture 
of  one  or  both  of  the  malleoli,  is  an  accident 
by  no  means  uncommon. 

The  signs  of  this  partial  luxation  of  the  tibia 
forwards  are  nearly  the  same  as  those  we  have 
stated  to  belong  to  the  complete  luxation  in 
this  direction  ;  they  are,  however,  as  might  be 
expected,  more  faintly  marked,  and,  conse- 
quently, may  more  easily  be  neglected ;  but, 
after  all,  these  signs  are  so  evident,  that  it  is 
wonderful  how  with  common  attention  they 
can  be  overlooked.  It  may  not  be  amiss  to 
subjoin  the  following  case  as  illustrative  of  the 
common  partial  luxation  forwards : — 

A  man,  aged  twenty- two  years,  was  ad- 
mitted into  Jervis  -  Street  Hospital,  at  three 
o'clock,  A.M.  of  the  26th  of  December,  1833. 
He  stated  that  he  and  a  friend  had  been 
drinking  together  in  a  public  house,  that  in 
the  middle  of  the  night  they  quarrelled,  that 
he  was  knocked  down,  and  was  unable  to  rise, 
in  consequence  of  his  having  received  a  severe 
injury  of  his  left  ankle  :  his  friend  then  pro- 
cured some  assistance  and  carried  him  to  the 
hospital;  at  my  visit,  I  found  him  in  bed, 
complaining  of  much  pain,  his  leg  extended 
and  resting  on  its  outer  side ;  the  heel  was  re- 
tracted, and  between  it  and  the  calf  of  the  leg, 
instead  of  the  ordinary  line  which  marks  the 
course  of  the  tendo  Achillis,  there  was  a 
conspicuous  semicircular  curve,  (Jig-  57, «,  b); 
in  a  word,  the  heel  was  lengthened,  and  the 
dorsum  of  the  foot  seemed  much  shortened ; 
in  the  situation  of  the  ankle-joint  in  front, 
there  was  a  remarkably  hard,  prominent,  trans- 
forme  internum,  quitting  all  the  articulatory  sur- 
face of  the  astragalus,  excepting  a  small  portion  on 
its  fore  part,  against  which  the  tibia  is  applied." 
Now,  a  single  glance  at  the  skeleton  of  a  foot  will 
shew  us,  that  a  portion,  however  small,  of  the  ar- 
ticulatory surface  of  the  astragalus,  together  with, 
secondly,  the  upper  part  of  the  neck  of  this  bone  ; 
thirdly,  the  os  naviculare ;  and,  fourthly,  the  os 
cuneiforme  internum,  nearly  form  a  space  equiva- 
lent to  a  third  of  the  length  of  the  whole  foot, 
an  extent  of  surface,  which,  manifestly,  the  arti- 
culating portion  of  the  dislocated  tibia  could  not 
occupy. 


verse  ridge  made  by  the  advance  of  the  lower 
extremity  of  the  tibia  and  extensor  muscles  of 
the  toes,  while  beneath  this  there  was  a  marked 
depression,  where  the  skin  and  annular  liga- 
ment seemed,  as  it  were,  pinched  in,  drawn 
under  the  lower  edge  of  the  articular  part  of 
the  tibia;  the  foot  was  pointed  downwards, 
no  movement  of  flexion  or  extension  could  be 
communicated  to  the  ankle-joint,  but  it  ad- 
mitted of  some  little  motion  in  a  horizontal, 
and  also  in  a  lateral,  direction,  when  the  leg 
was  firmly  grasped  with  one  hand  and  the  foot 
moved  with  the  other. 

It  was  remarkable  that,  although  the  man 
had  no  power  whatever  over  the  motions  of 
the  joint,  he  could,  while  he  lay  in  bed,  move 
his  whole  limb  about  with  much  freedom,  and 
(as  there  was  probably  a  locking  of  the  bones 
with  each  other)  these  voluntary  movements 
were  not  accompanied  by  any  increase  of 
pain. 

The  fibula  could  be  felt  to  be  fractured 
about  an  inch  and  a  half  above  the  lowest 
point  of  the  outer  malleolus,  "  the  foot,  the 
outer  malleolus,  and  short  portion  of  the 
broken  fibula,  formed  one  system  of  parts," 
and  were  carried  for  the  length  of  an  inch  or 
more  horizontally  backwards,  while  there  was 
a  projection  forwards,  of  the  lower  articular 
part  of  the  tibia,  and  the  internal  malleolus 
itself  was  advanced  in  the  same  proportion : 
it  is  to  be  observed,  that  there  was  no  crepitus, 
because  it  was  the  deltoid  ligament  only  which 
was  torn ;  the  tibia  was  not  broken,  and 
the  ends  of  the  fractured  fibula  were  evidently 
far  separated  from  each  other.  When  the 
luxation  was  reduced,  which  was  effected  with- 
out much  difficulty,  crepitus  could  be  felt, 
proving  the  restoration  to  its  place  of  the 
lower  fragment  of  the  fibula. 

This  is  a  species  of  fracture  and  luxation, 
which  can,  by  proper  management,  be  readily 
redressed,  and  no  deformity  remains,  if  time 
be  not  lost  after  the  accident  has  occur- 
red ;  but  if  the  fibula  become  solidly  united 
in  its  new  situation,  the  motions  of  the  ankle- 
joint  are  for  ever  lost,  and  the  patient  is  doomed 
to  lameness  for  life. 

In  the  month  of  September  1833,  a  woman, 
aged  fifty-three  years,  was  admitted  into  Jervis- 
street  Hospital,  whose  left  ankle-joint  presented 
all  the  characters  above  assigned  to  the  partial 
dislocation  forwards  of  the  tibia,  combined  with 
a  simple  fracture  of  the  fibula ;  she  stated  that 
she  had,  two  months  previously,  broken  her 
leg  close  to  the  ankle  joint,  and  had  been  at- 
tended at  her  own  house,  from  a  dispensary,  by 
a  pupil,  who  applied  pads  and  lateral  splints, 
but  when  after  a  time  all  the  splints  were  re- 
moved, she  found  that  her  limb  was  deformed, 
her  ankle  stiff,  her  foot  rigidly  extended,  and 
pointed  downwards,  so  as  to  be  nearly  useless 
to  her;  as  two  months  had  elapsed  since  the 
accident,  before  she  applied,  no  promise  of 
relief  could  be  held  out  to  her.  She  there- 
fore left  the  hospital,  but  not  before  I  was 
enabled,  through  the  kindness  of  Mr.  Sutton, 
to  obtain  a  cast  of  the  leg  and  foot,  from 
which  figures  57  and  58  are  copied.  As  I 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


161 


Partial  luxation  forwards  of  the  tibia  at 
the  external  ankle,  with  fracture  of  the  fibula 
near  the  malleolus. 

Fig.  57. 


Viewed  on  the  external  side. 


Fig.  58. 


Viewed  on  the  internal  side. 

a,  b,  semicircular  excavation  posteriorly,  and 
projection  of  the  heel  backwards ;  c  prominence 
formed  by  the  tibia  projected  on  the  dorsum  of  the 
foot;  d  displacement  of  the  external  malleolus 
backwards  along  with  the  foot. 

was  anxious,  before  these  pages  went  to  press, 
again  to  examine  this  case,  I  requested  Mr.  S. 
to  make  inquiry  about  her;  he  learned  that 
the  woman  died  dropsical  a  few  days  before, 
and  with  much  difficulty  procured  for  me  an 
opportunity  to  examine  the  limb,  which  on 
careful  dissection  presented  the  following  ap- 
pearances:— the  whole  extremity  was  somewhat 
wasted,  the  skin  on  the  sole  of  the  foot  was 
smooth  and  fine,  shewing  that  she  had  been 
able  to  walk  but  little  since  the  accident;  the 
foot  was  in  a  position  of  almost  rigid  extension, 
the  toes  were  directed  downwards,  the  range  of 
motion  of  flexion  and  extension  did  not  exceed 
one  inch,  in  short,  all  the  usual  characters 
assigned  to  the  partial  dislocation  forwards  of 
the  tibia  and  displacement  of  the  foot  back- 
wards were  seen;  when  the  skin  was  re- 
moved from  the  fascia  of  the  leg  and  foot, 
the  intervening  cellular  membrane  was  found 
infiltrated  with  serum,  the  skin  was  adherent 
to  the  inner  malleolus,  the  vena  saphena 
and  the  nerve  of  the  same  name  were  thick- 
ened and  firmly  connected  together,  the  ex- 
VOL.  i. 


tensor  tendons  were  stretched  over  the  tibia, 
and  were  somewhat  flattened,  and  the  grooves 
which  transmit  the  tendons  that  play  behind 
the  inner  and  outer  malleolus  were  deepened. 
We  now  directed  our  attention  to  the  state  of 
the  bones;  we  found  that  the  tibia  was  dis- 
placed forwards,  that  its  anterior  edge  was  ad- 
vanced more  than  one  inch  beyond  its  natural 
situation,  and  that  it  much  overhung  the  os 
naviculare,  but  such  was  the  direction  and  state 
of  obliquity  of  the  tibia  with  respect  to  the 
foot,  that  it  could  not  be  said  to  rest  upon  that 
bone ;  between  the  os  naviculare  and  the  infe- 
rior articular  extremity  of  the  tibia  there  inter- 
vened much  fat  of  a  yellow  hue  and  fibrous 
texture,  like  intervertebral  substance ;  the  inter- 
nal malleolus  itself  had  not  escaped  injury,  the 
deltoid  ligament  had  not  in  this  instance  as  in  the 
former  given  way  f  the  internal  malleolus  itself 
had  been  broken,  and  a  small  portion  of  the  back 
part  of  the  edge  of  the  articular  cavity  of  the  tibia 
was  detached,  and  both  malleoli  were  retracted, 
or  carried  backwards  with  the  foot;  the  fibula 
above  the  fractured  portion  was  directed  down- 
wards and  a  little  forwards,  and  was  somewhat 
parallel  to  the  tibia,  yet.  more  than  naturally 
approximated  to  it,  a  circumstance  which  ac- 
counted for  the  contracted  rounded  form  the 
middle  of  the  leg  possessed ;  the  lower  frag- 


Fig.  59. 


Viewed  on  the  external  side. 
Fig.  60. 


Viewed  on  the  internal  side. 


Skeleton  preparations  of  fig.  57  and  58. 
M 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


ment  of  the  fibula  was  directed  from  below 
upwards,  a  little  inwards,  and  very  much  for- 
wards, so  as  to  make  with  its  shaft  a  remark- 
able angle  salient  anteriorly;  this  bone  had 
been  traversed  by  the  fracture  obliquely,  from 
above  downwards  and  from  before  backwards. 
The  external  malleolus  was  placed  about 
one  inch  and  a  quarter  behind  its  usual  situa- 
tion, and  was  consequently  dislocated  at  its 
tibio-fibular  articulation,  having  burst  those 
strong  ligaments  which  connect  these  bones 
together,  and  which  are  so  seldom  found  to 
yield. 

Luxation  of  the  bones  of  the  leg  backwards 
at  the  ankle-joint. — A  luxation  of  one  or  both 
bones  of  the  leg  at  the  ankle-joint  backwards, 
whether  the  accident  be  what  has  been  called 
complete  or  incomplete,  whether  accompanied 
with  a  fracture  of  the  fibula,  or  merely  with  a 
rupture  of  the  ligaments,  is  a  displacement 
which  must  be  considered  exceedingly  rare. 
Boyer,  in  his  valuable  work,  gives  no  case  of 
it  from  his  own  observation ;  and  in  alluding 
to  such  an  accident,  states  that  no  author,  to 
his  knowledge,  has  given  a  single  example  of 
it.  Sir  A.  Cooper  evidently  has  not  seen  it; 
for  he  says,  "  1  have  seen  the  tibia  dislocated 
in  three  different  directions,  inwards,  forwards, 
and  outwards ;  and  a  fourth  species  of  disloca- 
tion is  said  sometimes  to  occur,  viz.  back- 
wards." Baron  Dupuytren  states  that  he  has 
never  seen  this  accident.* 

Mr.  Colles  has  given  me  the  notes  of  one 
case,  and  it  is  the  only  one  he  can,  in  his  exten- 
sive experience,  recollect  to  have  met  with,  of 
a  partial  dislocation  of  the  lower  part  of  the 
tibia  and  fibula  backwards,  and  has  also  shewn 
me  the  cast  he  had  taken  of  the  leg.  In  this 
case  the  tibia  seemed  thrown  partially  back- 
wards, from  the  articular  pulley  of  the  astraga- 
lus; the  fibula  was  unbroken,  and  was  also 
carried  backwards  with  the  tibia;  the  foot, 
measured  from  the  instep  upon  its  dorsum,  was 
longer  than  that  of  the  opposite  side,  the  heel 
was  shorter  and  less  pointed,  the  space  in  front 
of  the  tendo  Achillis,  near  to  the  os  calcis, 
was  partially  filled  up,  and  a  hard  swelling  oc- 
cupied the  lower  and  back  part  of  the  tibia, 
which  was  evidently  formed  by  a  quantity  of 
callus,  which  had  cemented  together  the  frag- 
ments of  a  fracture  of  the  lowest  part  of  the 
tibia;  the  leg  was  shorter  than  the  opposite 
limb. 

It  would  have  been  interesting  to  have  learned 
the  precise  manner  in  which  this  accident  had 
occurred  ;  but  as  to  this,  or  the  immediate 
symptoms  which  followed  the  injury,  I  could 
get  no  satisfactory  information.  The  man  did 
not  apply  to  Stevens's  Hospital  until  the  bones 
were  united  in  their  new  and  faulty  position. 
Besides  the  partial  dislocation  backwards  of  the 
tibia,  this  bone  with  the  outer  malleolus  of  the 
fibula  was  inclined  somewhat  outwards;  and 
the  man  walked  lame  and  most  awkwardly  on 

*  Je  n'ai  jamais  vu  de  luxation  du  pied  en  avant, 
dans  les  fractures  du  perone  et  de  Textremite  du 
tibia. — Annuaire  Medico-Chirurgical,  1819,  Paris 
p.  159. 


the  outer  edge  of  the  heel  and  foot,  the  inner 
side  of  which  was  somewhat  curved  inwards. 

I  have  had  occasion  to  notice  a  displace- 
ment of  the  tibia  backwards  on  the  os  calcis, 
in  a  case  where  the  astragalus  sloughed  in  con- 
sequence of  a  compound  injury  to  the  external 
malleolus  and  ankle-joint;  but  such  a  case  is 
different  from  that  now  under  our  considera- 
tion, although  the  possibility  of  such  an  occur- 
rence should  not  be  lost  sight  of. 

2.  Morbid  anatomy,  a.  Acute  inflammation 
of  the  synovial  membrane  of  the  ankle-joint 
produces  changes  in  the  synovial  fluid  of  the 
articulation  both  in  quantity  and  quality,  and 
alterations  very  generally  in  the  appearance  and 
structure  of  the  membrane ;  I  say  very  generally, 
for  I  have  known  an  exception  to  the  rule,  in  a 
case*  of  acute  synovitis  of  the  ankle-joint  which 
caused  the  death  of  the  patient  in  fifty  hours 
from  its  first  onset ;  during  the  whole  of  the 
time  the  patient  never  slept  nor  ceased  to  com- 
plain of  the  agonizing  pain  of  the  ankle-joint. 
At  the  post-mortem  examination,  before  the 
skin  was  removed,  the  extensors  of  the  toes  were 
observed  to  be  displaced  by  the  fluid  which 
distended  the  synovial  sac  of  the  articulation, 
and  fluctuation  was  now,  as  during  life,  to  be 
felt  in  two  tumours  which  existed  in  front  of 
the  two  malleoli ;  the  interior  of  the  joint  was 
occupied  by  a  turbid  oily  synovial  fluid;  no 
false  membrane  existed,  and  if  there  had  been 
increased  vascularity  during  life,  no  trace  of  it 
was  discoverable  at  the  time  of  examination  : 
increased  quantity  with  altered  quality  of  the 
synovial  fluid  were  the  only  deviations  from 
the  normal  condition  which  could  be  noticed. 
Portions  of  the  synovial  membrane  are,  how- 
ever, occasionally  found  covered  with  false 
membrane.  Pus  has  also  been  found  in 
the  joint,  sometimes  laudable,  sometimes 
foetid,  and  of  a  brownish  red  colour;  the 
membrane  has  been  found  thickened,  and  has 
afforded  evidence  of  increased  vascularity,  and 
even  in  some  points  has  presented  a  villous  ap- 
pearance. In  very  young  subjects  I  have  known 
acute  inflammation  of  the  ankle-joint  in  a  few 
days  extend  itself  to  the  epiphysis,  and  produce 
separation  of  it  from  the  shaft  of  the  tibia ;  and  in 
such  cases  a  displacement  of  the  shaft  inwards, 
and  of  the  epiphysis  and  foot  outwards,  occurs 
from  the  action  of  the  muscles,  as  in  Pott's  luxa- 
tion. Acute  inflammation  commencing  in  the 
synovial  membrane  of  the  ankle-joint  sometimes 
extends  farther  than  this :  there  have  been  cases 
in  the  Richmond  Hospital,  and  the  specimens 
have  been  preserved  in  the  museum,  of  acute 
synovitis  of  the  ankle  in  which  the  inflammation 
extended  through  the  vascular  junction  of  the 
epiphysis  and  shaft  of  the  tibia,  and  having 
occupied  the  cellular  junction  of  the  periosteum 
with  the  anterior  and  inner  surface  of  the  tibia, 
soon  ended  in  the  formation  of  pus  and  lymph, 
which  detached  from  the  bone  its  immediate 
covering,  and  produced  effects  which  termi- 
nated in  the  death  of  the  patient.  I  have  seen 
this  detachment  of  the  lower  epiphysis  of  the 
tibia  in  an  infant  six  days  old,  the  result  of  acute 

*  See  Dublin  Journal,  vol.  iv.  p.  1. 


ABNORMAL  CONDITION  OF  THE  ANKLE-JOINT. 


IGiJ 


synovitis,  with  purulent  deposition  in  the  joint, 
and  in  a  young  man  aged  twenty,  but  have  not 
observed  it  ever  to  occur  in  older  subjects  ;  and 
conclude  that  it  is  one  of  the  consequences  of 
synovitis  of  the  ankle-joint,  which  is  only  to  be 
noticed  at  an  age  when  the  epiphyses  are  not 
yet  consolidated  with  the  shaft  of  the  tibia. 

In  these  very  acute  attacks  of  inflamma- 
tion, its  ravages  are  seldom  confined  to  the 
structure  which  seemed  to  be  the  'point  du 
dipurC  of  the  disease ;  the  cartilages  are  in 
some  cases  removed  from  the  tibia,  fibula,  and 
upper  surface  of  the  astragalus  with  astonishing 
rapidity;  the  porous  surface  of  the  bones  has 
also  been  found  exposed,  and  their  substance 
to  afford  evidence  of  its  having  been  in  a  state 
of  inflammation.  Surgeons  should  ever  bear 
in  mind,  that  the  synovial  membrane  of  the 
ankle-joint  passes  very  far  forwards  on  the 
upper  surface  of  the  astragalus,  even  as  far  as 
within  a  few  lines  of  the  junction  of  this  bone 
with  the  os  naviculare,  so  that  an  accidental 
wound  high  upon  the  instep  might  very  readily 
give  rise  to  a  fatal  synovitis  of  the  ankle-joint. 
Moreover,  by  an  experiment  on  the  dead  sub- 
ject, it  may  be  shown  that  a  very  slight  direc- 
tion too  much  upwards  of  the  edge  of  the  knife 
when  the  operation  of  partial  amputation,  ac- 
cording to  Chopart,  is  performed,  may  wound 
the  most  anterior  part  of  the  synovial  sac  of  the 
ankle-joint,  and  the  consequences  of  such  a 
mishap  might  prove  fatal,  or  at  all  events 
greatly  aggravate  the  ills  which  even  without 
such  cause  too  frequently  follow  Chopart's 
operation. 

Again,  the  synovial  membrane  extends  very 
low  down,  even  to  the  lowest  point  of  the  inner 
side  of  the  peroneal  malleolus,  along  the  outer 
or  fibular  surface  of  the  astragalus  (fig-  61,  «). 

It  has  very  frequently  happened  to  the  wri- 
ter's knowledge,  that  inflammation  commencing 
in  the  body  of  the  os  calcis,  or  in  the  fibrous  or 
synovial  tissue  of  the  articulation  between  the 
os  calcis  and  under  surface  of  the  astragalus,  has 
crept  up  to  the  ankle-joint  by  this  route  between 
the  fibula  and  astragalus;  when,  therefore,  opera- 
tions and  cauterizations  are  performed  by  surgeons 
to  cure  the  carious  state  of  the  os  calcis,  the  close 
contiguity  of  such  an  important  articulation  as 
that  of  the  ankle  should  be  recollected.  The 
great  proximity  of  the  ankle-joint  to  that  be- 
tween the  under  surface  of  the  astragalus  and 
os  calcis  can  only  be  estimated  by  making  a 
vertical  section  of  the  tibia,  fibula,  astragalus, 
and  os  calcis,  passing  transversely  across  these 
bones  and  through  the  malleoli,  as  may  be  seen 
in  fig.  61  ;  and  if  a  subject  be  selected  in  which 
the  epiphysis  has  not  been  consolidated  with 
the  rest  of  the  bone,  a  useful  view  may  be  had 
illustrating  many  of  the  preceding  practical 
observations,  and  explaining  clearly  how  in- 
flammation, traumatic  or  idiopathic,  once  esta- 
blished in  the  ankle-joint,  can  pass  through  the 
epiphysis  to  the  periosteum  of  the  tibia ;  and  ori- 
ginating either  in  the  body  of  the  os  calcis,  or  in 
some  of  the  structures  composing  the  articulation 
between  this  bone  and  the  under  surface  of  the 
astragalus,  can  be  propagated  to  the  ankle-joint : 
such  a  view  as  this  will  shew  the  necessity  of con- 


Fig.  61, 


sidering,  in  connexion,  the  normal  and  abnor- 
mal state  of  these  important  articulations. 

b.  Chronic  disease. — The  effects  of  chronic 
diseases  on  the  tissues  composing  the  ankle- 
joint  are  next  to  be  considered  ;  these  are  vari- 
ous, and  may  be  referred  to  the  influence  of 
specific  diseases,  such  as  gout,  syphilis,  struma, 
rheumatism,  &c.;  but  the  effects  of  most  of  these 
on  this  particular  articulation  need  not  here  be 
discussed,  as  they  will  be  sufficiently  dwelt  on 
elsewhere  in  this  work  (see  JOINT):  we  deem  it, 
however,  right  to  enter  somewhat  into  detail  in 
the  description  of  those  morbid  appearances  of 
the  ankle-joint  which  are  supposed  to  be  of  a 
scrophulous  origin,  and  which  are  denominated 
white  swelling  of  the  ankle-joint.  The  external 
characters  of  the  affection  are  pretty  much  those 
in  common  with  the  same  melancholy  disease, 
in  whatever  articulation  of  the  extremity  it  is 
situated ;  the  swelling,  at  first  soft,  and  appear- 
ing in  front  of  each  malleolus,  seems  divided 
into  two  by  the  extensor  tendons ;  after  a  time 
it  becomes  more  solid,  and  assumes  somewhat  of 
a  globular  form  ;  here  as  elsewhere,  however,  it 
does  not  completely  surround  the  joint.  The 
limb  above  is  wasted  and  the  heel  is  retracted  ; 
the  foot  is  cedematous,  and  the  toes  are  pointed 
downwards,  no  motion  of  flexion  or  extension 
can  be  communicated  to  the  foot ;  but  when  the 
bones  are  moved  laterally,  an  unnatural  motion 
is  communicated  to  the  foot,  and  a  grating  of 
rough  and  carious  surfaces  in  advanced  cases 
can  be  felt :  the  sides  of  the  swelling  are 
studded  over  with  numerous  fistulous  orifices, 
from  which  even  now  a  thin  sanious  matter  can 
be  pressed  ;  a  probe  introduced  passes  either 
directly  through  one  or  other  of  the  malleoli, 
or  by  a  circuitous  route  into  the  interior  of 
the  joint  through  the  sinuses,  which  are,  as 

M  2 


164 


ANNELIDA. 


it  were,  the  excretory  ducts  leading  from  the 
interior,  and  conducting  out  the  sanious  and 
sabulous  matter  which  proceed  from  the  dege- 
nerated cartilages,  synovial  membranes,  and 
bones  of  the  diseased  joint.  The  skin  is  thin, 
soft,  and  shining,  and  moveable  on  the  sur- 
face, except  where  the  tistulous  orifices  exist. 

The  anatomical  characters  of  this  disease  in 
its  advanced  stage  affecting  this  articulation  we 
have  many  opportunities  of  observing.  When 
the  superficial  coverings  of  the  swelling  are 
removed,  the  fat  is  remarked  to  be  consistent 
and  yellow,  the  cellular  tissue  interposed  be- 
tween the  ligaments,  tendons,  and  muscles  is 
infiltrated  with  a  viscid,  semi-fluid,  spongy, 
homogeneous  mass ;  sometimes  this  tissue  be- 
comes so  thick,  and  is  so  connected  with  the 
lateral  ligaments  of  the  ankle-joint,  and  so  in- 
terposed among  their  softened  fibres,  as  to  render 
a  clean  dissection  of  these  last  impracticable ;  so 
that  the  ligamentous  and  cellular  structures 
around  the  joint  appear  to  have  undergone  a 
species  of  fibre-cartilaginous  degeneration  ;  the 
viscid  glairy  matter  infiltrated  around  the  joint 
with  the  tumefied  ligaments  are  the  parts  which 
cause  the  principal  swelling,  and  give  to  the  fingers 
examining  it  that  deceptive  feeling  of  fluctuation 
which  characterises  the  white  swelling  wherever 
situated. 

The  few  muscular  fibres  to  be  found  near  this 
joint  are  pale  and  of  a  gelatinous  appearance, 
being  infiltrated  with  the  same  matter  as  that 
which  pervades  the  more  superficial  structures. 
The  tendons,  nevertheless,  preserve  their  natural 
colour  and  consistence.  The  periosteum  will 
be  found  much  thickened  and  easily  detached 
from  the  bone. 

The  bones  of  the  joint,  and  those  in  its  vici- 


nity, are  very  usually  more  or  less  atrophied, 
and  have  undergone  a  process  of  degeneration  ; 
notwithstanding,  however,  what  has  been  said 
on  high  authority  to  the  contrary,  these  bones 
are  occasionally  enlarged  and  expanded  ;  they 
have  lost  much  of  their  specific  gravity,  their 
spongy  tissue  is  softened,  yellowish,  and  easily 
penetrated  by  a  knife,  and  filled  with  a  matter 
resembling  adipocere,  or  a  yellow  semi-fluid 
fat. 

The  heel  it  has  been  noticed  is  elongated, 
and  the  foot  measured  from  the  tibia  to  the 
toes  on  the  dorsum  is  shortened  very  generally, 
and  pointed  downwards.  Dissection  discovers 
the  cause  of  this  frequent  phenomenon  in  a  par- 
tial dislocation  of  the  tibia  forwards  on  the 
astragalus,  the  softened  ligaments  allowing  the 
action  of  the  gastrocnemii  and  solaei  to  drag 
the  whole  foot  backwards.  In  the  interior  of 
the  articulation,  a  more  or  less  considerable 
quantity  of  a  sanious  matter  is  found;  while 
the  cartilages  covering  the  end  of  the  tibia 
and  fibula,  and  surfaces  of  the  astragalus,  are 
softened,  adhere  but  slightly  to  the  bones,  and 
have  been  partially  removed,  leaving  exposed 
the  porous  structure  of  the  latter. 

The  arteries,  veins,  and  capillaries  present  no 
peculiarity,  except  that  the  naturally  white 
ligamentous  tissue  is  more  freely  supplied  than 
usual  with  red  vessels.  The  neurilema  of  the 
posterior  tibial  nerve  is  evidently  much  thick- 


ened, so  as  to  give  it  an  appearance  of  enlarge- 
ment; the  small  nerves  around  the  joint  seem 
also  hypertrophied. 

(  R.  Adams.) 

ANNELIDA,  (a  generally  adopted,  but 
barbarous  latinization  of  the  French  term 
'  Annelidas,'  from  '  Annellus,'  a  little  ring ; 
ought  rather  to  be  written  <  Annulata'or  '  An- 
nellata.') — The  natural  group  of  Annelida 
comprehends  all  the  invertebrated  animals 
which  have  a  soft  body  divided  into  transverse 
segments  or  rings;  a  distinct  central  nervous 
system  disposed  in  the  form  of  a  longitudinal 
gangliated  chord,  blood  coloured  (generally 
led),  and  contained  in  a  system  of  appropriate 
and  very  distinct  vessels ;  and,  lastly,  organs  of 
locomotion,  consisting  either  of  flesjiy  appen- 
dages provided  with  bristles,  or  of  bristles  only ; 
or  of  a  prehensile  cavity  situated  at  each  ex- 
tremity of  the  body  ;  but  never  of  articulated 
members,  as  in  the  Arachnida,  Crustacea,  and 
Insecta. 

The  establishment  of  this  class  is  due  to 
Cuvier.  Prior  to  him,  Pallas,  Miilhsf,  and 
Otho  Fabricius,  had  made  observations  of  great 
interest  on  the  animals  of  which  it  is  com- 
posed; and  we  find  in  the  writings  of  the 
author  of  the  Miscellanea  Zoologica  the  most 
happy  ideas  respecting  the  natural  relations 
which  these  animals  bear  to  one  another. 
Nevertheless,  these  works  had  at  first  but  little 
influence  on  the  classification  of  the  Inverte- 
brata,  and  for  a  long  time  naturalists  persisted  in 
following  the  method  of  Linnaeus,  who  united 
under  the  term  Vermes,theMollusca,  Zoophyta, 
and  Annelida,  and  dispersed  the  latter  in  three 
different  sections  of  that  great  class;  confound- 
ing some  with  the  Entozoa  (intestinal  worms), 
others  with  the  Acephalous  Mollusca,  and  others 
again  with  the  Testacea. 

It  was  in  the  work  entitled  "  Tableau  Ele- 
mentaire  de  1'Histoire  Naturelle  des  Animaux," 
published  in  the  years  1797-8,  that  M.  Cuvier 
laid  the  first  foundation  of  a  natural  distribution 
of  invertebrated  animals.  He  collected  together 
in  the  class  Vermes  the  species  which  more  lately 
have  constituted  the  groups  of  Annelida  and 
Entozoa,  and  established  in  it  the  two  divisions 
corresponding  to  those  which  are  generally 
adopted  at  the  present  day.  Having  subse- 
quently determined  the  presence  of  red  blood 
in  the  leech,  and  having  investigated  the  circu- 
lating apparatus  in  these  animals,  Cuvier  sepa- 
rated the  "  red-blooded''  from  the  "  intestinal" 
worms,  and  constituted  for  the  former  a  distinct 
class,  to  which  Lamarck  afterwards  gave  the 
name  of  "  Annelides,"  which  has  been  gene- 
rally adopted,  and  is  used  at  the  present  day 
by  most  naturalists.* 

This  classification  being  based  essentially  on 
anatomical  structure,  has  been  adopted  by 
Lamarck,  Dumeril,  Savigny,  Leach,  Latreille, 


*  See  Cuvier,  Bulletin  des  Sciences  par  laSociete 
Philomathique,  an  vii.  et  x.  Lamarck,  Discours 
d'ouverture  du  cours  des  Animaux  sans  Vertebres 
prononce  en  Mai  1806,  et  Histoire  des  Animaux  sans 
Vertebres, 


ANNELIDA. 


165 


&c.,  but  is  not  received  by  all  zoologists  of  the 
present  day.  M.  De  Blainville,  in  his  metho- 
dical distribution  of  the  animal  kingdom,  has 
adopted  another  plan.  Taking  the  exterior 
organs  for  the  base  of  his  system,  this  naturalist 
divides  the  articulate  animals,  which  he  terms 
"  Entomozoaires,"  into  seven  classes,  of  which 
the  penultimate,  viz.,  the  "  chetopodes,"  com- 
prehends the  Annelidans  provided  with  loco- 
motive bristles,  and  of  which  the  last,  viz,  the 
"  apodes,"  is  composed  of  the  Annelidans  des- 
titute of  those  organs,  together  with  the  planariae 
and  intestinal  worms.* 

The  general  plan  of  organization  exhibited 
in  the  animals  which  are  grouped  together  by 
Cuvier  under  the  name  of  "  vers  intestinaux," 
and  the  numerous  affinities  which  connect  the 
planarivE  and  several  helminlha  to  the  Annelida, 
appear  to  us  fully  to  justify  a  partial  adoption 
of  the  innovations  introduced  by  M.  De  Blain- 
ville, and  to  indicate  that  the  natural  position 
of  the  white-blooded  worms  is  by  the  side  of 
those  with  red  blood,  at  the  bottom  of  the  sub- 
kingdom  of  articulate  animals;  whilst  in  the 
system  of  Cuvier  the  Annelida  are  placed  at 
the  head  of  that  great  division  of  the  animal 
kingdom,  and  the  entozoa  are  left  among  the 
zoophytes.  But,  on  the  other  hand,  similar 
reasons  appear  to  us  to  oppose  the  adoption  of  the 
divisions  which  M.  De  Blainville  has  proposed 
for  the  articulate  animals.  That  zoologist,  in 
fact,  establishes  a  distinction  between  his  che- 
topoda  and  apoda  as  wide  as  between  the  former 
and  the  insecta,  arachnida  and  Crustacea,  and 
thus  separates  from  the  setiferous  annelidans  to 
place  among  the  intestinal  worms  the  hirudines, 
which  approximate  to  the  former  and  deviate 
from  the  latter  in  many  of  the  most  important 
points  of  their  organization  ;  for  example,  in  the 
existence  of  a  gangliated  nervous  system. 

This  arrangement  does  not  appear  to  us  to 
accord  with  the  spirit  of  a  natural  classification, 
in  which  the  several  divisions  ought  to  be  in- 
dicative of  the  different  degrees  of  importance 
which  the  modifications  of  the  animal  organiza- 
tion present. 

In  the  present  state  of  science  the  class  An- 
nelida ought  in  our  opinion  to  be  preserved 
nearly  as  it  was  established  by  Cuvier,  but 
should  be  joined  with  the  entozoa  and  rotifera, 
to  form  a  great  division  of  the  sub-kingdom 
articulata,  distinct  from  the  natural  group,  con- 
sisting of  insecta,  myriapoda,  arachnida,  and 
Crustacea.  The  affinities,  indeed,  between  the 
setiferous  annelidans  and  the  hirudines  are  too 
close  to  admit  of  their  being  arranged  in  sepa- 
rate classes ;  and,  on  the  other  hand,  every  day 
discloses  new  facts  of  a  nature  which  demon- 
strate that  the  vermiform  animals  pass  from 
one  to  another  by  almost  insensible  gradations. 
Thus  the  researches  of  M.  Dugbs  on  the 
planariae  show  how  closely  their  structure  ap- 
proaches that  of  certain  red-blooded  worms,  and 
the  distinction  founded  on  the  colour  of  the 
nutritious  fluid  no  longer  suffices  to  separate 

*  See  the  Bulletin  de  la  Soc.  Philomathique, 
1818  •,  De  1'Organization  des  Animatix  par  M.  de 
Blainville,  torn.  i.  table  7  ;  and  the  article  •  Vers'  of 
the  Dictionnaire  des  Sciences  Naturelles,  torn.  Ivii. 


them  ;  for  on  the  one  hand  it  is  proved  that 
the  colour  of  the  blood  is  yellow  and  not  red 
in  some  of  the  annelidans  properly  so  called; 
while  on  the  other  hand  1  have  recently  ob- 
served on  the  shores  of  the  Mediterranean  an 
animal  which  differs  from  the  genus  prostoma 
only  in  the  possession  of  red  blood.  We  now 
know  intestinal  worms  which  have  a  circulation 
and  a  vascular  system  as  well  formed  as  that  of 
the  annelida,  which  they  already  resemble  so 
much  by  their  outward  form.  The  absence  of 
a  rudimentary  nervous  system  in  the  entozoa  is 
called  in  question  by  skilful  anatomists.  Lastly, 
the  excellent  works  of  Ehrenberg  on  the  in- 
fusoria of  the  class  rotifera  prove  the  analogy 
that  exists  between  these  minute  beings  and  the 
articulate  animals  generally,  but  more  espe- 
cially to  the  annelida. 

The  differences  which  the  annelida  present 
among  themselves  have  necessitated  their  di- 
vision into  many  secondary  groups  or  orders. 
In  the  latest  work*  that  has  been  published  on 
the  classification  of  these  animals,  they  have 
been  divided  into  four  orders,  under  the  names 
of  Annelida  errant  ia,  Annelida  tubicola,  Anne- 
lida terricola,  and  Annelida  suctoria  (suceuses). 
This  classification  is  based  on  the  combination 
of  the  modifications  which  exist  in  the  struc- 
ture of  these  beings,  and  does  not  materially 
differ  from  that  proposed  by  M.  Cuvier  in  the 
Regne  Animal,  and  by  M.  Savigny  in  the 
great  work  on  Egypt. 

The  following  is  a  table  of  the  principal 
characters  which  distinguish  these  groups. 
First  Order. — ANNELIDA  ERRANTIA. 
Body,  with   soft  appendages  (cirri,  branchiae, 

or  antennae),   generally   disposed    over   the 

whole  length  of  the  animal,  and  not  collected 

towards  the  cephalic  extremity. 
Feet  generally  very  distinct,  armed  with  seta:  or 

bristles,  which  have  very  rarely  the  form  of 

hooks. 
Head  generally  distinct,  and  provided  with  eyes, 

antennae,  and   a   retractile   proboscis,  often 

with  jaws. 

(This  order,  which  nearly  corresponds  to  that 
of  the  Annelida  dorsibranchiata  of  Cuvier,  com- 
prehends the  genet*.  Apkrodita,  Polynoe,Polyo- 
dontes,  Acoetes,  Sigalion, Palmyra,  Amphinome, 
Chloeia,  Euphrosyne,  Hipponoe,  Eunice,  Onu- 
phis,  Diopatra,  Lysidice,  Lombrincreis,Aglaura> 
(Enone,  Nereis,  Syllis,  Hesione,  Alciope,  Myri- 
ana,  Pftyllodoce,  Nephtya,  Goninada,  Glycera> 
Aricia,  Aonis,  Ophelia,  Cirrhatulis,  Peripatus, 
Chetopterus,  Arenicola.} 

Second  Order. — ANNELIDA  TUBICOLA. 
Body,  with  soft  appendages,  for  the  most  part 

collected  together  at  the  cephalic  extremity. 
Feet,  almost  always  of  two  kinds,  generally  de- 
prived of  cirri,  and  armed  with  hooked  bristles. 
Head  not  distinct,  without  eyes,  antennae,  pro 

tractile  proboscis,  or  jaws. 
(This  order  corresponds  to  that  established  by 
Cuvier  under  the  same  name,  and  includes  the 

*  See  Classification  des  Annelides  et  description 
des  especes  qui  habitent  les  cotes  de  la  France, 
par  MM.  Audouiu  et  Milne  Edwards,  torn.  ii. 
des  Recherches  pour  servir  al'Hist.  Nat.  du  littoral 
de  la  France. 


166 


ANNELIDA. 


genera  Serpula,  Sabella,  Tercbella,  Amphitrite, 
Hermella,  and  Siphostoma.') 

Third  Order. — ANNELIDA  TERRICOLA. 
Body,  completely  destitute  of  soft  appendages. 
Feet,  scarcely  or  not  at  all  distinguishable,  and 

represented  only  by  some  bristles. 
Head  not  distinct,  without  eyes,  antennae,  or 

jaws. 
This  order  comprehends  the  genera  Clymena, 

Lumbricus,  Na'is,  fyc. 

In  the  classification  of  M.  Cuvier  it  is  united 
to  the  Hirudinida  to  form  the  order  Anne- 
lides  abranches. 

Fourth  Order. — ANNELIDA  SUCTORIA. 
Body  destitute  of  bristles  for  locomotion,  com- 
pletely apodous,   and  without   soft  appen- 
dages.    A  prehensile  cavity  in  the  form  of  a 
sucker  at  each  extremity  of  the  body. 
Head,  not  distinct,  but  generally  provided  with 

eyes  and  jaws. 

This  order  is  composed  of  the  family  of  Hiru- 
dinida, and  of  the  genus  Branchellion. 

External  conformation. — The  Annelida  have 
always  an  elongated,  generally  cylindrical,  and 
vermicular  form;  sometimes,  however,  they 
are  flat  or  more  or  less  oval.  The  body  is  com- 
posed, as  we  have  already  observed,  of  a  series 
of  rings,  not  of  a  horny  or  calcareous  texture  as 
in  the  majority  of  insects  and  Crustacea,  but 
membranous  and  separated  from  each  other 
only  by  a  transverse  fold  of  the  integument;  as  is 
seen  in  certain  larvae.  The  number  of  these  rings 
is  occasionally  very  considerable  (some  nereida 
have  more  than  500),  and  in  many  annelida  it 
varies  considerably  indifferent  individuals  of 
the  same  species,  and  seems  to  increase  with  age. 
In  some  instances  these  segments  are  sub- 
divided into  two  or  more  transverse  bands  by 
furrows. 

In  general  each  ring  supports  a  pair  of  mem- 
bers, and  when  an  apparently  single  segment 
gives  origin  to  a  greater  number  of  these  or- 
gans, it  is  easy  to  perceive  that  it  results  from 
the  union  of  many  rings  blended  together. 
The  two  extremities  of  the  body  are  sometimes 
dilated  in  the  form  of  suckers  (in  the  suctorious 
annelidans),  but  in  general  nothing  of  the  kind 
exists,  and  the  anterior  extremity  either  resem- 
bles the  rest  of  the  body,  or  it  terminates  in  a 
head  more  or  less  distinct  (as  in  the  nereida, 
see  Jig.  62),  often  supporting  eyes  (a),  and  fili- 

Fig.  62. 


form  appendages  called  antennae,  (b,c),  the  num- 
ber of  which  is  generally  three,  four,  or  five. 

The  mouth  is  situated  at  the  extremity  of  the 
body,  and  in  the  acephalous  annelida  is  di- 
rected forwards,  but  in  the  cephalous  species 
this  opening  is  situated  below  the  base  of  the 
head.  The  anus  is  placed  at  the  opposite  ex- 
tremity, and  is  almost  always  found  on  the 
dorsal  aspect  of  the  body.  A  certain  number 
of  Annelida  are  completely  apodous,  and  do 
not  present  the  least  trace  of  an  appendage  on 
any  of  the  segments  of  the  body  (the  hirudinidse). 
Others  exhibit  on  either  side  many  rows  of 
bristles,  which  fulfil  the  office  of  feet  (the  terri- 
colae).  In  others,  again,  the  bristles  of  which 
we  have  spoken  are  supported  on  a  fleshy 
tubercle  more  or  less  prominent,  and  more  or 
less  complicated  in  structure,  and  to  these 
organs  the  name  of  feet  is  applied. 

The  feet  of  the  Annelida,  when  they  present 
the  maximum  of  development  of  which  they 
are  susceptible  in  that  class  of  animals,  are  com- 
posed each  of  two  very  distinct  portions,  placed 
one  above  the  other,  and  appertaining  the  one  to 
the  dorsal,  the  other  to  the  ventral  arch  of  the 
ring.  (See/g.  63,which  represents  one  of  the  feet 


Fig.  63. 


of  an  amphinome.)  M.  Savigny,  who  was  the 
first  to  study  with  due  care  the  zoological  cha- 
racters furnished  by  these  appendages  of  the 
annelida,  gave  to  these  portions  of  the  feet  the 
names  of  dorsal  oar  (a)  and  ventral  oar  (6)  (rame 
dorsal  et  rame  ventral).  Sometimes  these  oars 
are  pretty  distant  from  one  another,  (fig.  63.) 
sometimes  they  are  separated  only  by  a  shallow 
fissure  (Jig-  64.  which  represents  the  foot  of  a 
nereid),  and  occasionally  they  are  so  intimately 
blended  together  that  they  can  hardly  be  dis- 


Fig.  64. 


ANNELIDA. 


167 


languished,  and  form,  as  it  were,  but  a  single 
organ  ;  lastly,  there  are  cases  in  which  only 
one  of  the  oars  would  seem  to  be  developed. 
If  one  were  disposed  to  compare  the  loco- 
motive system  of  the  annelida  with  that  of  tlie 
other  articulate  classes,  the  ventral  oar  should  be 
regarded  as  analogous  to  the  members  which  in 
the  Crustacea,  Insects,  &c.  are  variously  modified 
to  constitute  the  legs,  the  jaws,  or  the  antennae  : 
and  the  dorsal  oar  ought  to  be  considered  as 
representing  the  appendages,  which,  though 
wanting  in  the  greater  number  of  articulate 
animals,  yet  acquire  a  considerable  develop- 
ment on  the  last  two  rings  of  the  thoracic 
segment  of  most  insects  and  constitute  the 
wings.  In  this  particular  the  annelida  afford 
an  example  of  the  greatest  uniformity  in  the 
development  of  the  appendicular  system  in  the 
articulate  division  of  the  animal  kingdom. 

Each  oar  is  essentially  composed  of  a  fleshy 
tubercle  more  or  less  prominent,  which  sup- 
ports different  productions  of  the  integument, 
incloses  the  bristles  (c),  and  which  is  more 
especially  designated  by  the  name  of  foot. 
Towards  the  base  of  the  setiferous  tubercle 
there  is  generally  a  membranous  appendage, 
sometimes  filiform,  sometimes  lamelliform, 
called  the  cirrus  (d,  e) ;  lastly,  it  is  also  above 
the  margin  and  near  the  base  of  these  organs 
that  the  branchiae  (/)  take  their  origin,  but  in 
general  it  is  only  the  dorsal  oar  that  supports 
them.  All  the  above  parts  may  exist  simul- 
taneously, but-  it  often  happens  that  one  or 
more  are  atrophied  to  a  greater  or  less  degree, 
or  are  altogether  deficient;  and  this  either 
along  the  entire  body  or  on  certain  segments 
only.  Thus  in  the  terricolous  annelida  there 
are  no  cirri;  in  the  hermellae  they  are  pre- 
sent on  the  ventral,  but  not  on  the  dorsal  oar ; 
while  in  the  cirrhatulae  the  reverse  obtains. 

In  most  of  the  annelida  errantia  the  setiferous 
tubercle  of  both  oars  is  wanting  on  the  first 
rings  which  follow  the  head,  whilst  the  cirri 
assume  a  very  great  development,  and  form  the 
appendages  termed  by  systematic  authors  ten- 
tacular cirri.  (Fig.  62,  d.} 

A  similar  modification  may  be  frequently 
remarked  in  the  composition  of  the  appen- 
dicular system  of  the  last  ring  of  the  body,  and 
thence  results  a  certain  number  of  filiform  pro- 
ductions called  styles.  Lastly,  the  antennae  of 
the  annelida,  which  must  not  be  confounded 
with  the  antennae  of  insects  and  Crustacea,  may 
also  be  considered  as  representing  the  cirri  of 
the  dorsal  oar  of  those  rings,  the  union  of  which 
constitutes  the  head.* 

The  annelida  pass  in  general  a  somewhat 
stationary  life,  and  a  great  number  among 
them  remain  constantly  buried  in  the  earth  or 

*  For  further  details  regarding  the  external  struc- 
ture of  the  annelida  the  reader  may  consult  the 
excellent  work  of  M.  Savigny,  intitled  "  Systeme 
des  Annelides,"  principally  of  those  found  on  the 
coasts  of  Egypt  and  Syria;  the  article  '  Vers '  of 
the  Dictionnaire  des  Sciences  Naturelles,  torn.  Ivii. 
by  M.  De  Blainville ;  and  a  more  recent  publica- 
tion on  the  same  subject  inserted  in  the  Annales 
dos  Sciences  Nature-lies,  torn,  xxviii,  xxix,  and  xxx, 
and  in  the  second  volume  of  the  «  Rcchf-rches  pour 
servir  a  1'Hist.  Nat.  du  littoral  de  la  France,  par 
MM.  Audouin  et  Milne  Edwards.' 


enclosed  in  tubes  formed  by  the  mucus  which 
is  secreted  by  the  skin,  and  which,  while  hard- 
ening, commonly  agglutinates  together  frag- 
ments of  shells  and  sand.  The  formation  of 
these  sheaths  is  very  quick.  I  have  seen  them 
fabricated  in  the  course  of  a  few  hours.  Some- 
times they  are  of  extreme  tenuity,  occasionally 
they  are  as  tough  as  thick  leather,  and  there 
are  some  which  possess  very  considerable 
hardness  and  are  composed  in  great  proportion 
of  carbonate  of  lime,  like  the  shells  of  mol- 
lusca.  In  the  greater  part  of  these  animals 
locomotion  is  produced  by  general  undulations 
of  the  body  determined  by  contractions  of  a 
layer  of  muscular  fibres  extending  from  one 
ring  to  another,  and  fixed  to  the  inner  surface 
of  the  skin.  But  in  other  species  the  change 
of  place  is  effected  by  the  action  of  the  feet, 
of  which  we  have  spoken ;  or  by  the  contrac- 
tion of  the  tentaculae  which  surround  the 
mouth,  as  in  the  terebellae,  and  which,  by 
shortening  themselves,  drag  on  the  body  of 
the  animal  in  the  same  manner  as  the  arms  of 
the  cephalopods :  lastly,  by  the  action  of  the 
suckers  with  which  the  extremities  of  the  body 
are  furnished. 

The  bristles  (Jig.  63  and  64,  f,)  with  which 
the  feet  of  the  annelida  are  provided,  do  not  serve 
merely  as  little  levers  to  facilitate  their  move- 
ments, but  are  also  offensive  arms,  and  their 
structure  is  very  curious.  They  differ  con- 
siderably from  the  hairs  of  other  articulate 
animals,  which  are  nothing  more  than  small 
tubular  prolongations  of  the  epidermic  layer. 
By  their  mode  of  connexion  with  the  integu- 
ments and  their  mode  of  formation  they  ap- 
pear to  approach  the  hair  of  mammalia,  but 
their  disposition  is  of  a  more  complicated  na- 
ture. They  are  inclosed  in  sheaths  provided 
with  muscular  fibres,  by  the  aid  of  which  the 
animal  can  protrude  and  retract  them  again : 
in  general,  also,  they  are  not  merely  simple 
conical  filaments,  but  their  extremity  is  often 
shaped  like  a  harpoon,  a  lance,  or  a  barbed 
arrow,  and  the  annelidan  uses  it  to  inflict  a 
wound  upon  its  enemies.* 

Sensation. — Tactile  sensibility  is  considerable 
in  these  animals,  and  it  seems  to  reside  prin- 
cipally in  the  antennae,  the  cirri,  and  the 
tentacula.  They  do  not  appear  to  possess  a 
sense  of  hearing,  and  there  are  many  among 
them  which  do  not  manifest  any  sign  of  sen- 
sibility to  light ;  but  in  others,  eyes  (jig-  62,  «,) 
exist,  the  number  of  which  is  sometimes  very 
considerable,  but  the  structure  very  simple. 
They  are  coloured  points,  (generally  black,)  and 
situated  on  the  dorsal  aspect  of  the  head  or  on 
the  cephalic  sucker.  In  the  setiferous  anne- 
lida there  are  never  more  than  two  pairs,  but 
in  the  hirudinidae  or  leeches  their  number 
often  increases  to  eight  or  ten.  The  anatomy 
of  these  eyes  has  recently  been  studied  by 
Professor  Muller  of  Berlin,  and  according  to 
his  researches  it  would  seem  that  these  organs 
do  not  contain  a  crystalline  lens,  or  a  trans- 
parent body  analogous  to  the  vitreous  cones  of 


*  Sec  Observations  sur  les  Foils  des  Annelides 
consideres  rotnme  moyen  de  Defense,  par  MM. 
Audouin  et  Milne  Edwards,  op.  cit.  torn.  ii.  p.  31. 


168 


ANNELIDA. 


the  Crustacea  and  insecta,  but  consist  simply  of 
a  terminal  ganglion  of  the  optic  nerve  covered 
by  a  layer  of  black  pigment  and  placed  imme- 
diately beneath  the  integument,  which  is  thin  and 
transparent  at  that  part.* 

Nervous  system. — In  like  manner  the  ner- 
vous system  of  the  annelida 
Fig.  65.  is  verv  simple.     It  occupies 

._ a  the  middle  line  of  the  ventral 

— c  aspect  of  the  body,  and  con- 
sists of  a  double  series  of  mi- 
nute ganglions  of  medullary 
matter,  more  or  less  inti- 
mately united  or  even 
blended  together,  and  equal 
in  number  to  the  number 
of  rings.  ( See  Jig.  65.  repre- 
senting the  nervous  system 
of  the  aphrodita  aculeata). 
The  ganglions  give  origin 
to  lateral  branches,  and 
are  connected  together  by 
two  chords  of  communi- 
cation, sometimes  separate, 
sometimes  united  into  a  sin- 
gle trunk,  so  as  to  constitute  a 
longitudinal  chain  extended 
through  the  entire  length  of 
the  body.  The  first  of  these 
ganglions  (a)  is  lodged  in  the 
head,  or  at  least  at  the  ante- 
rior extremity  of  the  animal, 
in  front  of  or  above  the  di- 
gestive tube;  the  rest  are 
placed  below  that  canal ; 
whence  it  results  that  the  two 
nervous  chords  which  form 
the  media  of  communi- 
cation between  the  cephalic 
ganglion  and  the  first  of  the 
sub-cesophageal  series  pass 
along  the  sides  of  the  oeso- 
phagus, and  form  around  that 
canal  a  species  of  collar  or 
ring ;  a  character  which  is  common  to  all  the 
articulate  animals. f 

Organs  of'  digestion. — The  alimentary  canal 
in  the  annelida  extends  from  one  end  of  the 
body  to  the  other,  and  has  an  external  com- 
munication at  both  extremities.  The  mouth  is 
generally  provided  with  a  projectile  proboscis, 
which  is  formed  by  the  anterior  portion  of  the 
digestive  canal,  which  can  be  inverted  and  pro- 
truded like  the  finger  of  a  glove,  and  possesses 
muscles  for  the  express  object  of  effecting  these 
movements  (see  Jig.  66,  which  represents  the 

Fig.  66. 


*  See  Annales  des  Sciences  Nat.  torn.  xxii. 

+  See  Cuvier,  Anat.  Comparee,  torn.  i. ;  Trevi- 
ranus,  iiber  der  stachlichten  Aphrodite,  Zeitschrift 
f iir  Physiologic,  3  Band  ;  Moquin  Tandon,  *'  Mo- 
nograph, des  Hirudines/'  Morrem,  "  Sur  le  Lom- 
bric/'  &c. 


proboscis  of  a  phyllodoce,  and^g.  67,  that  of  a 
nereis).  The  surface  is  frequently  beset  with 
small  papillae,  and  its  extremity  armed  with 

Fig.  67. 


horny  jaws  (ni),  the  disposition  of  which  varies 
in  different  genera.  It  is  to  be  observed  that 
these  jaws  are  almost  always  placed  laterally 
like  the  mandibles  of  other  articulate  animals, 
and  cannot  act  upon  one  another  in  the  direc- 
tion of  the  axis  of  the  body,  as  in  the  vertebrata, 
but  are  not  to  be  regarded  as  analogous  to  the 
mandibles  and  maxillae  of  insects  and  Crustacea. 
In  their  structure,  the  jaws  of  the  annelida  ap- 
proximate rather  to  the  solid  plates  with  which 
the  interior  of  the  stomach  in  some  Crustacea  is 
provided,  and  to  the  hooks  which  arm  the 
mouth  of  certain  gasteropodous  molluscs.  This 
conformation  of  the  oral  apparatus  is  met 
with  only  in  the  annelida  errantia ;  in  the 
annelida  terricola  there  is  scarcely  a  vestige  of 
a  proboscis,  and  never  any  teeth  or  jaws.  In 
the  annelida  suctoria,  the  mouth,  which  is 
placed  at  the  bottom  of  the  cephalic  sucker,  is 
also  occasionally  protruded  in  the  form  of  a 
small  tubular  proboscis,  and  in  other  species 
its  margins  are  armed  with  little  horny  jaws  ; 
lastly,  in  the  annelida  tubicola,  nothing  of  the 
kind  is  to  be  seen,  but  in  general  the  superior 
border  of  the  mouth  forms  a  sort  of  projecting 
lip,  which  is  provided  with  long  tentacles, 
sometimes  simple  and  filiform,  sometimes  pec- 
tinated and  resembling  tufts.  In  certain  erratic 
annelida,  the  Agliope,  for  example,  there  are 
also  found  around  the  mouth  small  tentacula, 
which  are  quite  distinct  from  the  tentacular 
cirri,  and  which  appear  to  be  analogpus  to  the 
appendages  of  which  we  have  just  made 
mention. 

The  oesophagus  which  succeeds  the  pro- 
boscis or  mouth  presents  nothing  worthy  of 
notice,  but  it  is  in  general  quite  distinct  from 
the  stomach.  The  conformation  of  the  latter 
organ  varies  much.  Sometimes  the  stomach  is 
a  simple  enteroid  tube  (as  in  the  nereida  and 
terebellae) ;  sometimes  it  is  composed  of  two 
pouches,  of  which  the  first  is  membranous 
and  may  be  compared  to  a  crop,  while  the 
second  is  muscular  and  is  analogous  to  a 
gizzard,  as,  for  example,  in  the  lumbrici, 
thalassenuB.  In  other  cases  the  stomach  pre- 
sents on  either  side  a  succession  of  enlarge- 
ments which  have  in  general  the  form  of 
rounded  cells,  but  which  sometimes  consti- 
tute sacs  or  vast  and  much  elongated  ccecums, 
(as  in  some  hirudihes,/gs.  68  and  69.)  Lastly, 


ANNELIDA. 


169 


Fig.  68. 


Fig.  69. 


we  may  observe  that  these  ccecums  are  replaced 
by  blind  canals,  either  simple  or  ramified; 
thus  in  the  arenicola,  or  sand  worm,  we  find 
that  there  communicate  with  the  second  sto- 
mach two  ccecums  terminated  by  a  soft  point, 
with  thick  parietes  of  a  yellow  colour ;  and  in 
the  aphroditae  the  stomach  opens  on  either  side 
into  a  score  of  membranous  appendages,  which 
commence  of  very  contracted  diameter,  but 
afterwards  insensibly  become  dilated  and  di- 
vide into  many  branches :  (see  Jig.  70,  a,  the 
retracted  probos- 

Fig.  70.  cis,   b  bj  the  ap- 

pendages.) This 
type  of  structure 
leads  to  that  which 
is  manifested  in 
the  planariae,  and 
also  approximates 
to  what  one  sees 
in  the  parasitic 
arachnida. 

The  intestine 
which  succeeds 
the  stomach  is 
generally  narrow, 
and  in  the  majo- 
rity of  the  anne- 
lida  extends  in  a 
direct  line  to  the 
anus.  In  some 
species,  as  the 
amphitrites,  it 
presents  a  greater 
or  less  number 
of  convolutions. 
There  does  not 
exist  in  these 
animals  a  gland 
which  can  be  re- 
garded as  a  liver, 


properly  so  called  :  the  appendages  which  are 
grouped  around  the  stomach  in  the  arenicola: 
may,  indeed,  be  biliary  vessels  analogous  to 
those  of  insects  rather  than  true  cceca ;  but  in 
the  earthworms  and  many  other  annelides  the 
bile  would  seem  to  be  secreted  by  a  peculiar 
organ  of  a  yellow  colour  and  pulpy  texture, 
which  surrounds  like  a  sheath  a  great  part  of  the 
digestive  canal.  Lastly,  in  certain  annelida,  as, 
for  example,  the  thalassemae,  there  exists  on 
either  side  of  the  oesophagus  a  small  organ, 
which  would  seem  to  have  a  secretory  office, 
and  may  very  probably  be  a  salivary  gland.* 

Circulation. — The  blood  in  almost  all  the 
annelida  differs  from  that  of  every  other  in- 
vertebrate animal  by  its  red  colour;  some- 
times, however,  this  fluid  has  scarcely  a  tinge. 
According  to  M.  De  Blainville  the  blood  of 
the  aphroditae  is  yellow,  and  MM.  Mayor  and 
Gosse,  of  Geneva,  assert  that  the  circulating 
fluid  of  the  genus  clepsina,  one  of  the  hirudi- 
nidae  or  leech-tribe,  is  even  altogether  white. 
When  the  blood  of  an  annelide  is  examined 
with  the  microscope  it  is  seen  to  contain  circu- 
lar globules,  but  of  a  much  larger  size,  and  in 
far  less  number  than  in  human  blood  :  it  coa- 
gulates after  rest  like  the  blood  of  the  higher 
animals,  but  it  appears  to  contain  a  very  small 
proportion  of  fibrine. 

The  blood  circulates,  as  we  have  already 
stated,  in  peculiar  vessels,  which  its  red  colour 
renders  easily  distinguishable. 

The  vascular  system  has  been  best  studied 
in  the  earthworm :  above  the  alimentary  canal 
there  runs  along  the  entire  length  of  the  body 
a  contractile  vessel  (fig.  71,  a,)  which  is  con- 
sequently dorsal,  and  in  which 
the  blood  passes  generally 
from  behind  forwards,  some- 
times in  large  waves,  some- 
times by  small  quantities  pro- 
pelled by  the  successive  con- 
tractions of  the  divisions  which 
this  vessel  forms  through  its 
entire  extent.  A  portion  of  the 
circulating  fluid  then  passes 
into  another  vessel  (c),  which 
originates  at  the  anterior  ex- 
tremity of  the  one  above- 
mentioned,  and  which  runs 
backwards  along  the  ventral 
surface  of  the  body  below  the 
nervous  column,  from  which 
circumstance  it  has  been  cal- 
led the  sub-nerval  vessel  by 
Duges.  But  the  greater  part 
of  the  blood  which  is  con- 
tained in  the  dorsal  vessel,  in- 
stead of  following  this  chan- 
nel, passes  into  seven  or  eight 
pairs  of  large  lateral  branches 
composed  each  of  a  series  of 
dilatations  or  rounded  ve- 


*  See  Willis,  '  De  Anima  Brutorum  ;'  Pallas, 
*  Miscellanea  Zoologica ;'  Cuvier,  '  Anat.  Comp.' 
Treviranus,  op.  cit.  Moquin  Tandon,  op.  cit. ; 
Duges,  op.  cit.  j  Home,  <  Lectures  on  Comp. 
Anat.' 


Fig.  71 


170 


ANNELIDA. 


sides  (d),  which  are  highly  contractile.  These 
'  moniliform  vessels'  are  placed  in  a  situation 
corresponding  to  the  ovaries :  they  are  directed 
downwards  and  open  into  a  ventral  vessel  (6), 
which  occupies  the  middle  line  of  the  inferior 
aspect  of  the  animal,  following  the  same  track 
as  the  sub-nerval  vessel,  but  situated  less 
superficially.  Its  parietes  are  contractile,  and 
it  may  be  seen  alternately  dilating  and  con- 
tracting simultaneously  at  every  part  along 
the  whole  of  its  extent.  The  blood  flows 
into  this  ventral  vessel  from  before  backwards, 
and  leaves  it  to  re-enter  the  dorsal  vessel 
by  passing  through  the  branches  (e)  which 
ascend  perpendicularly  to  join  the  latter,  on 
either  side  of  the  alimentary  canal,  which  they 
thus  embrace,  and  to  which  they  furnish  a  great 
number  of  ramifications.  The  blood  con- 
tained in  the  sub-nerval  vessel  flows  equally 
from  before  backwards,  and  ascends  to  re-enter 
the  dorsal  vessel  by  lateral  channels  (/),  ana- 
logous to  the  anastomosing  vessels  which  we  have 
just  described,  but  situated  more  superficially 
than  those.  These  superficial  transverse  or 
dorso-abdominal  vessels,  as  they  are  termed  by 
M.  Duges,  severally  receive  a  large  branch 
from  their  corresponding  deep-seated  dorso- 
abdominal  vessel,  and  distribute  to  the  skin  a 
number  of  ramifications  which  appear  to  be 
specially  destined  to  bring  the  blood  into 
contact  with  the  oxygen  necessary  for  respi- 
ration.* 

In  the  genus  na'is  the  moniliform  vessels, 
which  in  the  earthworm  perform  in  some  degree 
the  office  of  a  composite  heart,  seem  to  be  re- 
placed by  a  single  pair  of  wide  veins,  which  are 
contractile  and  analogous  to  a  divided  heart,  and 
both  the  superficial  and  deep-seated  transverse 
vessels  by  which  the  blood  ascends  to  the 
dorsal  trunk  seem  to  rise  from  one  and  the  same 
ventral  trunk;  so  that  the  circulatory  appa- 
ratus is  more  simple  in  these  annelida  than 
in  the  earthworms.  The  same  plan  pervades  the 
sanguiferous  system  in  the  other  setiferous  an- 
nelidans,  in  which  the  branchiae  are  distributed 
throughout  the  entire  length  of  the  body ;  but 
when  these  organs  are  collected  together  at  a 
determinate  point  of  the  anterior  extremity 
of  the  body  it  is  a  little  different.  Thus  in 
the  terebellae  the  ventral  vessel  is  seen  to 
bifurcate  and  to  form  two  lateral  branches 
which  have  the  form  of  an  arch,  and  which, 
after  having  passed  over  the  sides  of  the 
O3sophagus,  re-unite  above  that  tube  to  form  a 
single  trunk.  This  trunk  reaches  the  anterior 
extremity  and  gives  origin  to  three  pairs  of 
primary  branches,  which  descend  to  the  vesi- 
cular receptacles  at  the  base  of  the  branchiae, 
and  distribute  the  blood  to  these  organs. 

In  the  leech-tribe  the  vascular  system,  on 
the  contrary,  is  more  complicated,  for  the  san- 
guiferous circle  is  composed  of  four  longitu- 
dinal trunks,  and  the  branches  which  bring 
them  into  communication  with  each  other. 
Of  the  four  longitudinal  vessels  two  occupy 
the  dorsal  and  ventral  aspects  of  the  mesial 

*  See  Duges,  '  Recherches  suv  les  Annclides 
abranches,'  Anuales  des  Sciences  Nat.  t.  xv. 


line,  and  two  the  sides  of  the  body.  The 
dorsal  and  ventral  trunks  communicate  toge- 
ther by  dorso-abdominal  branches  correspond- 
ing to  each  segment  of  the  body.  The  lateral 
trunks  also  render  to  the  dorsal  trunk  a  series 
of  dorso-lateral  branches,  and,  moreover,  mu- 
tually communicate  by  a  series  of  abdomino- 
lateral  branches  which  glide  transversely  be- 
neath the  nervous  chords.  The  dorsal  and 
ventral  vessels  are  evidently  analogous  to  those 
which  we  have  designated  by  the  same  names 
in  the  earthworm  and  na'is;  and  the  lateral 
vessels  may  be  compared  to  the  sub-nerval 
trunk  of  the  earthworm,  except  that,  instead 
of  being  single  and  situated  in  the  mesial  line, 
they  form  a  circle  in  which  the  blood  undu- 
lates sometimes  in  one  direction,  sometimes  in 
another,  but  always  pursuing  an  opposite 
course  in  the  two  canals.  Lastly,  in  addition 
to  the  above  *  general  circulation,'  there  is 
observed  in  the  leech-tribe  something  ana- 
logous to  the  l  lesser  circulation/  (fig-  72)  : 

Fig.  72. 


this  is  effected  in  the  branches  (6,  e)  of  the  dorso- 
lateral  vessels  («),  which  are  for  the  purpose  of 
bringing  the  blood  into  contact  with  the  aerated 
water  contained  in  the  small  membranous 
vesicles  (./)  situated  at  the  sides  of  each  seg- 
ment of  the  animal,  and  opening  externally 
upon  the  inferior  aspect.* 

Respiration. — From  what  has  been  said  of 
the  mechanism  of  the  circulation  in  the  annelida, 
it  will  be  seen  that  respiration  must  be  effected 
either  in  the  vesicles  above  mentioned,  or  on  the 
surface  of  the  body.  Such  in  fact  is  the  case ; 
the  skiu  is  in  general  the  seat  of  that  function  ; 
but  in  the  greater  number  of  instances,  the 
integument,  instead  of  maintaining  the  same 
texture  throughout,  and  acting  upon  the  air  in 
the  same  manner  at  every  point  of  its  extent, 
presents  at  particular  spots  peculiar  modi- 
fications, and  thus  gives  rise  to  special  organs 
of  respiration  called  '  branchiae.' 

The  branchiae  of  the  annelida  are  almost 
universally  membranous  appendages,  highly 
vascular,  fixed  to  a  certain  number  of  the  feet 
of  the  animal,  or  inserted  upon  the  back  near 
the  base  of  these  organs. 

In  the  nereida  and  some  other  congeneric 
annelida,  the  appendages  which  are  designated 
branchiae,  and  which  in  fact  seem  to  be  in  an 

*  See  Moquin  Tandon,  op.  cit.    Duges,  op.  cit. 


ANNELIDA. 


171 


Fig.  73. 


especial  manner  subservient  to  respiration,  are 
simply  a  kind  of  papillae  or  laminated  cutane- 
ous productions  very  little  or  not  at  all  sub- 
divided, attached  either  to  the  extremity  or 
base  of  the  feet  and  distributed  in  an  almost 
uniform  manner  over  the  entire  length  of  the 
body,  (fig.  64,  /*,/,/.)  In  the  eunice,  and  other 
allied  genera,  their  position  is  the  same,  but 
they  assume  the  form  of  an  elongated  filament, 
furnished  with  a  series  of  prolongations  of  a 
similar  filiform  shape,  disposed  like  the  teeth 
of  a  comb,  and  traversed  longitudinally  by  a 
canal  filled  with  red  blood,  (Jig.  73,./'.)  In 
the  amphinomian  family, 
as  in  the  former  groups, 
these  branchiae  are  placed 
on  almost  every  segment 
of  the  body,  so  that  these 
organs  form  along  the  whole 
extent  of  the  back  a  double 
row ;  but  here  their  struc- 
ture is  more  complicated,for 
the  filaments  are  extremely 
subdivided,  (fig.  63,  /.) 
In  the  arenicoltf,  the  form 
of  the  branchiae  is  almost 
the  same  as  in  the  amphinomes,  but  they  are 
limited  in  their  position  to  the  middle  seg- 
ments of  the  body.  In  the  genus  terebella 
the  branchiae  are  also  highly  ramified  vascular 
appendages  to  the  integument,  but  their  num- 
ber is  inconsiderable,  and  they  are  all  inserted 
near  the  cephalic  extremity  of  the  back.  In 
the  serpulae,  the  membrane  which  forms  a 
sort  of  thoracic  disc  near  the  cephalic  ex- 
tremity of  the  body,  ought  to  be  regarded  as 
an  organ  of  respiration,  and  it  is  probable  that 
the  tentacles  surrounding  the  mouth  like  a 
crown  of  plumes  are  subservient  to  the  same 
function.*  In  the  hirudinse  respiration  is  in 
part  effected  by  the  external  skin,  but  there 
exists  in  these  annelida  a  series  of  small  mem- 
branous sacs,  which  communicate  externally 
each  by  a  minute  orifice  situated  on  the  ven- 
tral aspect  of  the  body :  these  sacs  derive  from 
the  numerous  vessels  which  ramify  upon  their 
parietes  a  considerable  quantity  of  blood. 
Water  penetrates  into  these  organs  and  seems 
to  subserve  a  true  respiratory  purpose.  These 
sacs  are  commonly  denominated 


sacs,7  and  some  authors  think  that  they  receive 
into  their  interior  atmospheric  air  in  a  gaseous 
form.  Their  number  varies  from  fifteen  to 
twenty,  and  it  may  be  observed,  when  a  living 
leech  is  irritated  after  being  recently  removed 
from  water,  that  a  small  quantity  of  liquid 
escapes  from  their  apertures. 

In  the  lurnbrici  terrestres  there  is  in  like 
manner  found  in  each  segment  and  on  eitherside 
of  the  digestive  tube,  an  enteroid  vessel  folded 
upon  itself,  containing  a  liquid  and  opening 
outwardly  by  a  particular  pore.  These  sacs 
are  less  vascular  than  in  the  leeches;  never- 
theless there  is  reason  to  believe  that  they  fulfil 
an  analogous  office,  and  perform  a  more  or  less 


*  See,  for  additional  details,  the  works  already 
cited  of  Savigny,  De  Blainvillc,  and  Audouin  and 
Milne  Edwards. 


important  part  in  respiration.  Lastly,  it  has 
been  proved  that  in  the  annelida  there  are 
other  pores,  placed  on  the  back,  which  tra- 
verse directly  the  dermo-muscular  envelope, 
and  communicate  with  a  cavity  intermediate  to 
the  muscles  and  intestines,  and  imperfectly 
divided  by  transverse  septa,  into  which  air  or 
water  can  penetrate.  This  structure  may, 
indeed,  belong  to  the  respiratory  apparatus, 
but  science  does  not  yet  possess  sufficient  data 
to  solve  that  question.  An  analogous  dis- 
position has  been  observed  in  the  nai's.* 

Generation. —  The  generative  apparatus  is 
only  very  imperfectly  understood  in  the  anne- 
lida. It  appears  that  all  these  animals  are 
hermaphrodite,  but  that  they  cannot  fecundate 
themselves ;  the  intercourse  of  two  individuals 
being  necessary  for  the  accomplishment  of  the 
act  of  generation.  It  is  in  the  earthworm  and 
leech  that  this  part  of  their  anatomy  and  phy- 
siology has  been  most  completely  studied. 

In  the  leeches  the  sexual  apertures  are  placed 
at  the  inferior  surface  of  the  body  towards  the 
anterior  third,  and  separated  from  one  another 
by  the  intervention  of  five  segments.  The 
anterior  aperture  belongs  to  the  male  organs, 
and  at  the  season  of  reproduction  a  filiform 
and  highly  contractile  penis  is  observed  to  be 
protruded  from  that  part,  (fig.  74,  75,  a.) 


Fig.  75. 


This  communicates  in- 
ternally with  a  narrow 
cylindrical  canal  (b\ 
which  in  its  turn  opens 
into  a  kind  of  whitish 
vesicle  of  a  pyriform 
shape  (c)  commonly  cal- 
led the  vesicula  semi- 
nalis.  On  each  side 
of  this  vesicle  there 
is  an  oval  whitish  body 
(rf)  composed  of  con- 
torted tubes  filled  with  a  whitish  liquid :  each 
of  these  organs  is  a  testicle ;  and  they  seve- 
rally give  origin  to  a  slender  vas  deferem 
(fig.  75,  e)  of  the  same  colour,  which  opens 
into  the  vesicula  seminalis.  Lastly,  from  the 
posterior  extremity  of  the  testicle,  another  fili- 
form duct  (/)  is  continued,which  passes  back- 
wards on  each  side  of  the  nervous  cord,  and 
gives  origin  to  a  series  of  pedunculated  vesicles 
filled  with  a  whitish  fluid  similar  to  that  which 

*  For  the  structure  of  the  pulmonary  sacs,  see 
Willis,  op.  cit.  Thomas,  '  Memoires  pour  servir 
a  1'Histoire  Naturclle  des  Sangsues.'  Home  '  Lec- 
tures on  Comp.  Anatomy,'  Moquin  Tandon,  op.  cit. 
Morren  de  Lumbric.  tcrrest.  Duges,  op.  cit. 


172 


ANNELIDA. 


Fig.  76. 


is  contained  in  the  rest  of  the  apparatus. 
These  organs  (Jig.  74,  g)  are  generally  regarded 
as  accessory  vesicles,  and  they  vary  both  in 
number  and  form  in  different  species. 

The  female  apparatus  is  of  much  less  mag- 
nitude, but  also  presents  a  sufficiently  com- 
plicated structure :  it  is  situated  between  the 
two  canals  leading  to  the  accessory  vesicles  of 
the  male  apparatus,  and  is  a  little  posterior  to 
the  penis.  The  external  orifice,  of  which  we 
have  already  spoken,  communicates  with  a  short 
canal  (jig.  74  and  76,  //),  of  a  greyish  colour, 
which  leads  to  a  sort  of 
pouch  (i).  This,  accord- 
ing to  some  authors, 
is  analogous  to  an  ute- 
rus, but  in  the  opi- 
nion of  other  natura- 
lists is  merely  a  copu- 
lative vesicle  for  the  pur- 
pose of  retaining  the 
fecundating  liquid  which 
is  there  deposited  by 
the  male  in  the  act  of 
copulation.  This  sac  is  bent  upon  itself,  and 
a  duct  (j)  may  be  observed  to  be  continued 
from  the  anterior  extremity  which  leads  to  the 
ovaries  (k) :  these  are  small  whitish  bodies  two 
in  number,  and  in  close  approximation  to  one 
another. 

In  the  earthworm,  the  only  parts  that  can  be 
regarded  as  male  organs  are  some  sacs  or 
vesicles  varying  in  number  from  two  to  seven, 
and  situated  in  a  longitudinal  series  on  either 
side  of  the  ventral  aspect  of  the  body  towards 
its  anterior  extremity.  Each  of  these  vesicles 
adheres  to  the  parietes  of  the  splanchnic  cavity, 
by  a  small  canal  opening  directly  outwards  by 
pores  placed  on  the  posterior  and  inferior  part 
of  the  corresponding  ring:  there  is  farther  a 
canal  of  communication,  which  is  continued 
directly  from  one  vesicle  to  another  of  the 
same  lateral  series ;  and  at  the  season  of  co- 
pulation there  is  found  in  the  interior  of  these 
organs  a  viscid  liquid  abounding  with  seminal 
microscopic  animalcules.  The  outlets  of  the 
female  apparatus  occupy  the  sixteenth  segment 
of  the  body,  and  are  continuous  internally 
with  two  narrow  canals  directed  forwards,  and 
situated  on  the  internal  side  of  the  above 
mentioned  vesicles.  Having  reached  the  ova- 
ries, each  of  these  canals  (Jig-  77,  «)  divides 
into  two  branches  (6), 
which  bend  inwards  and 
terminate  by  a  globular 
enlargement  (c).  This  is 
seen  with  the  assistance  of 
the  microscope  to  be  itself 
formed  by  a  continuation 
of  the  canal  puckered  up 
into  numerous  folds, which 
are  enveloped  in  a  com- 
mon membrane.  To  each 
of  these  enlargements  are 
appended  a  pair  of  ova- 
ries, the  entire  number 
of  which  is  consequently  eight,  four  on  either 
side.  The  colour  of  these  ovaries  is  whitish, 
their  texture  pulpy,  and  their  interior  is  beset 


Fig.  77. 


with  numerous  minute  vesicles,  which  are  the 
ova.  At  the  period  of  copulation  the  ovaries 
are  filled  with  a  whitish  fluid,  which  is  pro- 
bably the  spermatic  secretion,  but  it  is  not 
easy  to  comprehend  how  the  male  apparatus 
can  introduce  it  into  that  part.*  According 
to  Redi,  the  ova,  after  being  detached  from  the 
oviduct,  pass  along  the  whole  extent  of  the 
body  towards  the  vicinity  of  the  anus,  whence 
they  are  expelled  by  two  orifices  stated  to  be 
near  the  termination  of  the  alimentary  canal 
or  to  open  in  its  interior.  According  to  Mon- 
tegre  it  is  the  fetus  and  not  the  ovum  which 
traverses  the  body  to  escape  by  the  above 
passages,  and  the  lumbrici  according  to  this 
view  are  viviparous.  This  statement  has  been 
adopted  by  many  authors  without  perhaps 
sufficient  examination;  but,  according  to  recent 
observations  by  Duges,  it  would  seem  not  to 
be  correct,  and  that  what  have  been  regarded 
as  the  young  of  the  earthworm  are  in  fact  a 
species  of  intestinal  worm. 

In  the  na'is  the  male  organs  are  less  nume- 
rous than  in  the  lumbrici,  but  differ  very  little 
in  other  respects.  They  consist  of  a  single 
pair  of  vesicles  opening  externally  by  a  wind- 
ing canal,  which  terminates  by  a  small  fissure 
on  the  eleventh  segment  of  the  body.  The 
ovaries  are  disposed  in  four  principal  masses, 
between  which  there  winds  a  long  oviduct, 
of  which  the  extremity  can  be  protruded  out- 
wardly like  a  penis.-j- 

In  some  annelida,  as  the  clepsina  carena, 
the  ova  are  developed  and  hatched  before 
exclusion,  so  that  the  young  are  born  alive; 
but  most  of  the  class  are  oviparous,  and  what 
is  very  remarkable,  the  same  ovum  sometimes 
incloses  the  germs  of  many  embryos :  this  is 
the  case  in  the  earthworm,  each  ovum  of  which 
produces  two  individuals,  and  in  the  leech  the 
ova  contain  severally  as  many  as  eighteen 
embryos.  One  might  at  first  view  suppose 
that  the  same  circumstances  obtained  in  the 
na'is;  but  what  appears  to  be  an  ovum  with 
multiplied  germs  is  in  reality  nothing  more 
than  an  aggregate  of  simple  ova. 

Reproduction. — Some  annelida  not  only  per- 
petuate the  race  by  the  ordinary  modes  of  gene- 
ration, but  enjoy  the  singular  faculty  of  pro- 
ducing new  individuals  by  a  transverse  division 
of  the  body.  A  na'is  or  an  earthworm  cut  in 
two  and  placed  under  favourable  circum- 
stances, will  continue  to  live,  and  each  moiety 
will  become,  in  appearance  at  least,  a  perfect 
animal.  This  fact,  which  was  first  determined 
by  Reaumur  and  Bonnet,  has  since  been  veri- 
fied by  M.  Duges,  Sangiovanni,  and  many 
other  observers :  the  anterior  portion  of  the 
animal  reproduces  a  new  tail,  and  the  posterior 
portion  developes  a  head. 

That  faculty  which  the  two  portions  of  the 
earthworm's  body  possess  of  manifesting  the 


vital   properties    independently   of    one   ano- 
her,   and  even  after  having  been   separated, 


may   be   explained    to    a    certain    degree  by 
the   known    structure   of    these   animals   and 

*  See  Willis,  Duges,  &c. 
f  See  Duges,  op.  cit. 


ANUS. 


173 


the  general  laws  of  physiology.  With  the 
exception  indeed  of  the  generative  organs 
which  are  concentrated  in  a  peculiar  part  of 
the  body,  it  is  easy  to  observe  that  each  seg- 
ment of  the  body  is  almost  the  exact  repe- 
tition of  all  the  rest :  they  all  possess  the  same 
organs,  and,  however  the  total  number  of  rings 
may  vary,  there  results  no  change  of  any  im- 
portance in  the  general  structure  of  the  animal. 
Now  it  may  be  laid  down  as  a  law  in  phy- 
siology, that  a  parity  of  organization  neces- 
sitates a  similitude  of  action ;  and  it  results 
that  as  in  depriving  an  earthworm  of  a  given 
number  of  segments  no  organ  is  removed  of 
which  it  does  not  still  retain  the  analogue,  no 
function  is  completely  destroyed;  and  conse- 
quently that  if  such  a  mutilation  should  weaken 
the  vital  action,  it  does  not  change  its  nature. 
Tin's  holds  good  for  both  the  segments  of  the 
animal :  each  continues  to  possess  all  the 
organs  essential  to  individual  existence,  and 
consequently  if  their  resisting  energy  be  suf- 
ficiently great,  there  can  be  no  reason  why  they 
should  not  continue  to  live  independently  of 
one  another,  and  become  two  distinct  worms.* 
But  if  the  anterior  moiety  thus  becomes  a 
perfect  animal,  it  is  probable  that  this  may 
not  happen  to  the  posterior  portion,  but  that 
the  new  individual  formed  by  this  part  will 
always  continue  deprived  of  generative  organs. 
For  the  anterior  moiety  retains  exclusively  the 
reproductive  organs  of  the  original  individual, 
and  there  is  nothing  which  authorizes  the  belief 
that  the  earthworm  possesses  the  power  from 
being  simply  mutilated,  of  reproducing  the 
whole  apparatus  on  any  part  of  the  posterior 
moiety.  This,  however,  is  a  circumstance  which 
it  would  be  easy  to  determine. 

From  the  sketch  that  we  have  given  of  the 
organization  of  the  annelida,  it  will  be  seen 
that  there  exists  in  this  branch  of  zoology  many 
hiatuses.  Anatomists,  in  fact,  have  hardly 
paid  attention  to  any  but  the  leech,  the  earth- 
worm, and  the  na'is,  and  we  possess  only  a 
vague  notion  of  the  internal  structure  and 
physiology  of  the  erratic  and  tubicolar  species; 
their  comparative  study  would  form  an  interest- 
ing subject  of  research. 

BIBLIOGRAPHY.— Cuvier,  Anat.  Comparee,  t.  i. 
— Bulletin  dcs  Sciences  par  la  Societe  Philoma- 
thique,  an  vii.  et  x.  Lamarck,  Discours  d'ouver- 
ture  du  cours  des  animaux  sans  vertehres,  pro- 
nonce  en  Mai  1806,  et  Histoire  des  animaux  sans 
vertebres.  Blainville,  De  1 'organization  des  ani- 
maux, t.  i.  tab.  7 — Dictionnaire  des  Sciences 
Naturelles,  art.  Vers,  t.  Ivii.  Audouin  fy  Milne 
Edwards,  Recherches  pour  servir  a  Fhistoire  natu- 
relle  du  littoral  de  la  France,  t.  ii.  Moquin  Tandon, 
Monograph,  des  Hirudines,  4to.  Montp.  1827. 
Morrem,  De  lumbrici  terrest.  hist.  nat.  4to.  Bruss. 
1829.  Pallas,  Miscellanea  Zoologica,  4to.  Lugd. 
Bat.  1775.  Home,  Lectures  on  Comp.  Anat.  Duges, 
Annales  des  Sc.  Nat.  t.  xv.  Thomas,  Memoires 
pour  servir  a  1'histoire  nat.  des  sangsues,  8vo.  Paris, 
1806.  Muller,  Vermium  terrestriura  et  fluviatilium, 
&c.  historia,  2  parts,  8vo.  Copenhag.  and  Lips. 
1773-74 ;  Ejus,  Von  Wurmern  des  siissen  und 
salzigen  Wassers,  4to.  Kopenhag.  1771 ;  Ej.  Zoo- 

*  See  the  article  Organisation  of  the  '  Dictionaire 
Classique  d'Histoire  Naturelle,'  and  the  Intro- 
duction to  my  '  Elemens  de  Zoologie/ 


logiaDanica,  fol.  Copenh.  1788-1806.  Schweigger, 
Handb.  d.  Naturgeschichte  d.  skeletlosen  ungeglie- 
derten  Thieren,  8vo.  Leipz.  1820.  Weller,  Circa 
animalium  quaedam  classium  inferiorum  incremen- 
tum  etvitam,  8vo.  Halle,  1817.  Klein,  Descript. 
Tubulorum  marinorum,  4to.  Danz.  1777.  Otto,  De 
Sternapside  et  Liphostomate  diplochaito,  vermibus 
duobus  marinis,  4to.  Bresl.  1820.  Leo,  De  struc- 
tura  lumbrici  terrestris,  4to.  Regiom.  1820.  Clesius, 
Beschreibung  d.  medicinischen  Blutigels,  8vo. 
Hadamar,  1812.  Kuntxmann,  Anat.-Physiol.  un- 
tersuchung  iiber  d.  Blutigel,  8vo.  Berl.  1817.  Krtolg, 
Naturhist.  Abhandlung  uberd.  Blutegel,  8vo.  Wien. 
1820.  Johnson,  A  treatise  on  the  medicinal  leech, 
8vo.  Lond.  1816— Further  Obs.  on  the  leech,  8vo. 
Lond.  1820.  Poupart,  Anat.  Hist,  of  the  leech  from 
Journ.  des  Svavans  1697,  Phil.  Trans.  1697.  Mo- 
rand,  Anatomic  de  la  Sangsue  :  Mem.  de  Paris, 
1739.  Bebiena,  De  Hirudine  sermones  quinque  : 
Comment.  Bonon.  t.  7.  Cuvier,  Sur  les  vaissaux 
Sanguins  des  sang-sues  :  Soc.  Philom.  An  7. 
Wichmann,  Vom  Gu'rtel  des  Regenwurms  :  Beschaft. 
der  Gesells.  Naturforsch.  Bd  3.  Chamisso,  De  ani- 
malibus  e  classe  Vermium  in  circumnavig.  terrse 
observatis,  4to.  Berol.  1819.  Delle  Chiaje,  Mem. 


de  structura  lumbrici  terrestris,  4to.  Berl.  1820. 
Olivi,  Zoologia  Adriatica,4to.  Bassano,  1792.  Sorg, 
Circa  respirationem  insectorum  et  vermium,  12mo. 
Rudolst.  1805.  Savigny,  Mem.  sur  les  animaux 
sans  vertebres,  8vo.  Paris,  1816 ;  Ejus,  Systeme 
des  annelides,  dans  le  grand  ouvr.  sur  1'Egypte, 
fol.  Paris. 

(H.  Milne  Edwards.) 

ANUS,  (in  anatomy,)  from  Anus  vel  An- 
nus,  a  round,  a  circle,  (syn.  ostium  recti, 
podexj  culus.  Gr.  9T£&;xTo$.  Fr.  anus.  Germ . 
After.  Ital.  ano.)  is  a  term  commonly  applied 
to  the  lower  extremity  of  the  rectum  :  properly 
speaking,  it  is  the  inferior  orifice  of  the 
alimentary  tube,  through  which,  in  the  higher 
orders  of  animals,  the  excrementitious  portion 
of  the  food,  as  also  the  excretions  from  the  di- 
gestive apparatus,  are  discharged  ;  for  obvious 
reasons  it  is  endowed  with  powers  to  assist  in 
expelling,  as  also  with  the  faculty  of  retain- 
ing these  for  a  considerable  tiine  :  such  oppo- 
site but  important  qualities  would  infer  the 
existence  of  a  somewhat  complicated  muscular 
apparatus,  more  or  less  under  the  influence  of 
the  will,  as  also  a  structure  in  other  respects 
worthy  of  attention. 

The  presence  of  an  anus  indicates  a  complex 
system  of  digestive  organs  ;  hence  in  many  of 
the  inferior  or  simpler  classes  of  the  invertebrate 
division  of  animals  it  is  absent,  and  in  many 
of  the  superior  of  this  division,  as  well  as  in 
several  of  the  vertebrata,  it  presents  considerable 
variety  as  to  structure,  function,  and  position. 
In  some  of  the  zoophytes,  such  as  the  in- 
fusory  animalcules  there  is  no  central  digestive 
cavity,  and  of  course  no  distinct  outlet.  In  them 
absorption  takes  place  by  imbibition  through 
pores  into  cells,  in  a  manner  somewhat  similar 
to  a  sponge ;  and  most  probably  excretion  (if  any 
occurs)  takes  place  through  the  same  orifices. 
In  others  of  this  class,  such  as  the  acalephae, 
where  a  rudimental  cavity  appears  in  the  body 
of  the  animal,  a  single  orifice  admits  the  food 
necessary  for  its  support,  and  the  excremeri- 
titious  portion  (if  any)  is  ejected  through  the 
same  opening.  In  the  actiniae,  also,  where  a 


174 


AN-US. 


distinct  stomach  exists,  and  where  the  retained 
matter  obviously  undergoes  certain  changes, 
the  one  orifice  serves  the  two-fold  purpose 
of  admission  to  the  food,  as  well  as  of  exit  to 
its  residuum.  Even  in  some  of  the  echino- 
dermata,  as  the  asteriae,  in  which  the  digestive 
apparatus  is  more  developed,  the  central  cavity 
becoming  more  complex,  the  latter  is  still  but 
a  cul  de  sac,  which  can  be  protruded  at  the 
mouth,  the  only  orifice  it  presents.  In  other 
species,  however,  of  this  class,  the  anus  ap- 
pears ;  thus  in  the  English  echinus,  where  the 
masticating  apparatus  is  so  remarkable,  this 
opening  exists  on  the  surface  of  the  animal, 
opposite  to  the  mouth.* 

Jn  the  sipunculi  the  anus  opens  near  the 
mouth,  and  in  the  holothuriae  near  the  respira- 
tory organ  .f 

In  the  several  families  of  the  articulata,  viz. 
insecta,  Crustacea,  and  vermes,  the  anus  exists, 
and  is  always  found  at  that  end  of  the  animal 
opposite  to  the  mouth,  and  most  generally  on 
its  inferior  surface. 

In  the  mollusca  it  is  also  present,  but  it 
holds  situations  singularly  differing  in  the 
different  orders  and  genera  of  this  class ;  thus 
in  the  cephalopoda,  as  the  cuttle-fish,  the 
rectum  opens  into  a  sort  of  cloaca,  which  is 
situated .  before  the  neck,  and  which  also  re- 
ceives the  semen  and  ova,  as  well  as  the 
secretion  from  the  ink-bag.  In  the  gastero- 
poda, as  the  slug,  it  is  generally  found  near 
the  pulmonary  cavity.  In  the  patella  or 
limpet,  however,  it  opens  on  the  head,  and 
in  the  doris  on  the  back,  surrounded  by  a 
delicate  fringe,  a  sort  of  branchial  tuft.  In 
most  of  the  acephala,  except  the  oyster,  the 
rectum  extends  along  the  back  of  the  animal, 
beneath  the  hinge,  and  above  the  respiratory 
organs ;  it  then  passes  through  the  heart,  and 
opens  above  the  posterior  muscle  of  the  shells, 
into  the  cavity  of  the  maulle,  or  between  its 
edges,  the  anal  opening  presenting  the  appear- 
ance of  a  fleshy  disc  or  sphincter. 

Among  fishes  the  anus  varies,  in  the  osseous 
and  cartilaginous  divisions  of  this  class ;  in  the 
former  it  usually  presents  the  appearance  of 
a  round  opening  leading  into  a  longitudinal 
groove ;  it  is  placed  in  front  of  the  anal  fin,  and 
of  the  urinary  and  genital  aperture,  contrary 
to  what  occurs  in  all  other  vertebral  animals. 
In  the  cartilaginous  fish,  as  the  ray  and  shark, 
this  groove  is  deeper,  and  has  the  appearance 
of  a  true  cloaca,  through  which  are  discharged, 
as  in  the  sepiae  and  in  birds,  not  only  the  alvine, 
but  also  the  urinal  and  seminal  excretions. 

In  reptiles  the  anus  serves  as  the  opening 
of  a  cloaca,  or  common  receptacle  of  the  re- 
siduum of  the  food,  as  well  as  of  the  urine, 
semen,  or  ova ;  in  the  batrachia,  as  the  frog, 
it  is  situated  at  the  end  of  the  back,  and  there- 
fore above  the  body  of  the  animal.  In  the 
chelonia,  as  the  tortoise,  it  is  under  the  tail. 
In  the  sauria  and  ophidia  it  is  a  transverse  cleft, 
but  in  the  salamander  it  is  a  longitudinal  fissure 
with  two  prominent  lips. 

*  Home's  Lect.  on  Comp.  Anat.  vol.  ii.  p.  76. 
f  Cuvier's  Comp.  Anat.  t.  iv.  p.  143. 


In  birds  the  rectum  expands  above  the  anus 
into  the  cloaca,  which  also  receives  the  ter- 
minations of  the  ureters,  the  ends  of  the  vasa 
deferent! a,  and  the  penis  (when  the  latter 
exists)  ;  also  the  openings  of  the  oviducts,  and 
of  the  bursa  Fabricii.  In  all  the  mammalia 
the  rectum  terminates  in  a  distinct  anal  open- 
ing, which  is  placed  at  the  posterior  or  in- 
ferior extremity  of  the  trunk,  directly  under 
the  origin  of  the  tail,  and  usually  in  a  direc- 
tion opposite  to  the  mouth,  and  in  all  it  is 
placed  behind,  and  not,  as  in  fish,  before  the 
urinary  and  sexual  orifice ;  in  some  few  of  the 
quadrumana,  as  the  mandril,  it  is  directed 
upwards.  In  almost  all  mammalia  it  is  a  dis- 
tinct orifice,  giving  passage  to  the  faeces  only  ; 
in  the  beaver  and  sloth,  however,  the  rectum 
and  urethra  have  a  common  termination.  The 
monotrematous  animals  also,  such  as  the 
echidni  and  ornithorhynci,  form  a  complete  ex- 
ception to  this  statement;  in  these  singular 
and  anomalous  creatures  a  single  opening  gives 
exit  to  the  faecal  and  urinary  secretions,  and 
also  subserves  sexual  purposes.  (See  INTES- 
TINAL CANAL.) 

ANUS  (in  human  anatomy).  In  the  present 
article  we  propose  to  examine  not  merely  the 
structures  which  immediately  bound  this  open- 
ing in  man,  in  their  normal  and  healthy  state,  as 
well  as  in  their  abnormal  and  diseased  condi- 
tions, but  we  shall  also  examine  the  parts  which 
enclose  and  surround  it,  and  which  can  exert  an 
influence,  direct  or  indirect,  on  its  functions ; 
that  is,  we  shall  consider  the  anatomy,  normal 
and  abnormal,  of  the  parts  contained  in  the 
Anal  Region. 

The  Anal  Region  is  synonymous  with  the 
posterior  portion  of  the  perinaeum  ;  its  triangular 
area  is  denoted  by  the  following  outlines :  the 
apex,  which  is  posterior  and  superior,  is  marked 
by  the  extremity  of  the  os  coccygis ;  its  base, 
which  is  before  and  below  the  latter,  is  defined 
by  an  imaginary  line  extending  transversely 
from  one  tuber  ischii  to  the  other,  and  each 
side  is  denoted  by  a  line  drawn  from  the  last 
named  process  to  the  point  of  the  coccyx  : 
these  lateral  boundaries  correspond  to  the  mar- 
gins of  the  glutaei  maximi  muscles,  which  over- 
lap the  inferior  or  the  great  sacro-sciatic  liga- 
ments; the  base  or  the  transverse  line  before 
mentioned,  separates  the  anal  from  the  anterior 
perineal  or  urethral  region :  in  the  adult  male 
this  line  will  be  found  to  be  about  three  inches, 
or  nearly  three  inches  and  a  quarter  in  length  ; 
in  the  female  it  is  about  half  an  inch  longer, 
and  more  certainly  so  if  the  individual  ex- 
amined have  borne  children ;  great  variety,  how- 
ever, has  been  found  to  exist  in  this  measure- 
ment, the  extremes  of  which  may  be  stated  at 
two  and  four  inches.  In  children  under  twelve 
years  of  age  this  transverse  diameter  of  the 
perinaeum  is  considerably  less,  in  consequence 
of  the  extreme  narrowness  of  the  pelvis  prior  to 
puberty. 

The  anal  region  contains  the  lower  portion 
of  the  intestinum  rectum,  several  muscles,  and 
fasciae,  some  nerves  and  vessels  of  importance, 
and  an  abundance  of  adipose  substance.  The 


ANUS. 


175 


quantity  and  consistence  of  the  adipose  substance 
found  in  this  region  vary  considerably  in  dif- 
ferent individuals  at  the  several  periods  of  life, 
and  under  various  conditions  of  health  ;  a  fact 
most  important  for  the  surgeon  to  bear  in  mind, 
inasmuch  as  this  diversity  causes  corresponding 
differences  in  the  physical  characters  which  this 
region  presents  under  these  particular  circum- 
stances. In  children,  and  in  the  female,  in  youth 
and  middle  age,  as  also  in  the  robust  and 
healthy  male,  this  region  will  be  found  plump, 
or  convex  around  the  anus,  whereas  in  the  ema- 
ciated, the  sickly,  or  the  old,  it  often  presents  the 
very  opposite  appearances;  and  a  proportional 
difference  may  be  observed  in  the  depth  of  the 
perinaeum,  or  in  the  distance  between  the  neck 
of  the  bladder  and  the  surface  :  the  greatest 
extremes  of  this  difference  have  been  found 
between  two  and  four  inches,  a  circumstance 
which  bears  materially  on  the  lateral  operation 
of  lithotomy. 

So  much  of  the  Rectum  as  lies  beneath  the 
cul  de  sac  of  the  peritoneum,  may  be  consi- 
dered as  appertaining  to  the  anal  region,  and 
must,  therefore,  be  noticed  at  present;  below 
the  reflection  of  that  membrane,  this  intestine 
descends  obliquely  forwards  between  the  sacrum 
and  bladder,  in  the  male  as  far  as  the  prostate 
gland,  and  in  the  female  as  far  as  the  vagina; 
it  is  there  on  a  level  with  the  inferior  extremity 
of  the  coccyx,  and  then  it  bends  downwards 
and  backwards,  and  ends  in  the  anal  opening  ; 
the  perinaeal  portion  of  the  Rectum,  therefore, 
is  convex  forwards  and  concave  towards  the 
coccyx ;  hence  in  introducing  into  this  intestine 
the  bougie,  enema  pipe,  or  even  the  finger,  it 
should  be  directed  at  first  upwards,  and  for- 
wards, and  then  upwards  and  backwards :  in 
the  child,  however,  this  precaution  is  not  ne- 
cessary, as  the  course  of  this  intestine  is  not  so 
much  curved,  the  name  of  Rectum  being  then 
more  correctly  applied  than  in  the  adult. 

In  order  to  examine  the  several  parts  con- 
tained in  the  anal  region,  the  thighs  should  be 
fully  separated,  flexed,  and  fixed  on  the  pelvis; 
the  first  object  which  attracts  attention  is  the 
Anus. 

This  opening  is  situated  in  the  median  line, 
at  the  bottom  as  it  were  of  a  deep  excavation, 
which  is  bounded  on  either  side  by  the  tube- 
rosity  of  the  ischium,  with  the  superincumbent 
muscular  and  adipose  substance ;  in  the  erect 
position  it  appears  at  a  great  depth  from  the 
surface,  in  consequence  of  the  approximation 
of  the  nates.  In  the  adult  the  anus  is  from  one 
inch  to  an  inch  and  a  half  distant  from  the 
point  of  the  coccyx,  and  three  inches  from  the 
arch  of  the  pubis ;  it  is  in  some  measure,  but 
not  perfectly,  fixed  in  its  situation,  anteriorly 
by  an  indirect  attachment  to  the  interosseous 
or  triangular  ligament  of  the  urethra,  and  pos- 
teriorly by  a  dense  fibrous  tissue,  which  forms 
a  sort  of  raphe  between  it  and  the  coccyx,  and 
to  which  the  muscles  and  integuments  adhere. 
In  the  natural  and  healthy  state,  the  anus  pre- 
sents the  appearance  of  a  small  rounded,  or 
rather  elliptical  orifice,  whose  border  is  thrown 
into  numerous  small  plaits,  or  ruga,  which 
during  the  extended  state  of  the  opening  are 


effaced  ;  these  rugae  are  occasionally  so  deep  as 
to  admit  of  the  escape  of  a  small  quantity  of 
fluid.  As  the  skin  approaches  the  margin  of 
this  opening  it  becomes  very  fine  and  delicate, 
is  gathered  into  those  several  radiated  folds  or 
plaits,  which  sink  into  it,  and  in  the  same  man- 
ner as  at  the  other  outlets  of  the  body,  it  be- 
comes continuous  with  the  lining  mucous  mem- 
brane of  the  intestine,  there  being  no  exact  line 
of  demarcation,  except  that  of  an  increased 
vascularity,  to  distinguish  the  one  from  the  other. 
This  plaited  condition  of  the  skin  which  lines 
this  opening  arises  from  the  close  contraction 
of  the  subjacent  muscle,  and  is  doubtless  de- 
signed to  admit  of  the  more  easy  dilatability 
of  the  anus  during  defecation;  this  opening, 
however,  is  never  equal  to  the  diameter  of  the 
rectum  at  a  little  distance  above  it.  In  the 
child  the  integument  surrounding  the  anus  is 
smooth  and  red,  in  the  adult  it  is  of  a  deep 
brown  colour  and  studded  with  several  fine 
hairs,  which,  however,  are  usually  absent  in  the 
female.  In  this  situation  also  the  cutaneous 
follicles  are  very  distinct  and  numerous,  but 
not  so  prominent  as  in  the  scrotum ;  they  secrete 
a  mucous  or  sebaceous  matter  which  gives  to 
the  skin  a  shining  or  oily  appearance,  and 
adapts  it  to  the  functions  of  the  part:  from  the 
absence  or  from  the  vitiated  condition  of  this 
secretion,  painful  and  troublesome  excoriations 
not  unfrequently  ensue.  In  the  healthly  state 
the  margin  of  the  anus  feels  firm  and  resisting, 
and  together  with  the  surrounding  muscles 
forms  a  floor  or  support  to  the  inferior  part  of 
the  pelvis,  in  the  centre  of  which  floor  the 
rectum  and  its  contents  are  maintained,  and 
on  either  side  a  mass  of  cellular  and  adipose 
substance. 

Muscles. — The  muscular  apparatus  connected 
with  the  lower  extremity  of  the  rectum  consists 
of  the  superficial  and  the  deep  sphincters  of 
the  anus,  also  the  right  and  left  levatores  am, 
to  which  may  be  added  the  two  transversi 
perincei,  and  the  two  coccygcei  muscles. 

The  first  two,  namely,  the  sphincter  muscles, 
surround  the  anus,  and  may  be  regarded  as  a 
modification,  or  as  a  particular  development  of 
the  general  circular  muscular  tunic,  which  is 
continued  around  the  whole  alimentary  tube 
from  the  mouth  to  the  anus,  and  which  in  dif- 
ferent situations  exhibits  a  considerable  increase 
in  colour  and  consistence,  for  example,  in  the 
lips,  around  the  fauces,  the  oesophagus,  the 
pylorus,  &c.  The  name  of  these  muscles  in- 
dicates their  principal  function,  while  the  other 
muscles  which  have  been  alluded  to  proceed  from 
certain  fixed  points  to  be  inserted  into  the  lower 
extremity  of  the  rectum,  and  must,  therefore, 
rather  serve  to  retain  the  anus  in  its  situation 
or  to  restore  it  to  its  natural  condition,  when 
in  the  exercise  of  its  functions  it  has  been  con- 
siderably dilated,  or  slightly  displaced  by  the 
expulsive  efforts  of  the  diaphragm  and  abdo- 
minal muscles.  We  shall  first  examine  the 
descriptive  anatomy  of  these  individual  muscles, 
and  then  consider  their  several  powers  or  pur- 
poses in  the  economy  of  the  surrounding  organs. 
Although  there  are  two  sphincter  muscles  of  the 
anus,  yet  this  name  is  generally  applied  to  the 


176 


ANUS. 


more  superficial  of  these ;  we  shall  distinguish 
these  muscles  by  the  names  of  sphincter  ani 
cutaneus  vel  ellipticus,  and  sphincter  ani  pro- 
J'undus  vel  orbiculuris. 

Sphincter  ani  cutaneus  (ertytyyu,  constringo,) 
coccygeo-anal,  sphincter  externus,  constrictor 
ani}  is  the  first  muscle  which  meets  the  eye  of 
the  anatomist  in  the  dissection  of  this  region. 
It  may  be  exposed  by  dividing  the  integuments 
from  the  coccyx  to  near  the  back  part  of  the 
anus,  and  thence  extending  an  incision  on  each 
side,  and  about  half  an  inch  distant  from  the 
edge  of  this  opening  to  its  forepart,  whence  it 
should  be  continued  indefinitely  along  the  me- 
dian line  of  the  perinaeum ;  the  integument 
should  then  be  carefully  dissected  off  from  either 
side  of  this  elliptical  incision. 

The  muscle  thus  exposed  is  thin  and  flat,  of 
an  elongated  and  elliptical  form,  and  cleft  in  the 
centre  to  embrace  the  opening  of  the  anus ;  it 
arises  posteriorly  fleshy  and  cellular  from  the 
point  of  the  coccyx,  and  from  a  tense  fibrous 
or  cellular  tissue,  called  the  recto-coccygceal  liga- 
ment, which  extends  from  the  coccyx  to  the 
back  part  of  the  anus,  where  it  divides  and  is 
lost  in  the  cellular  tissue  on  either  side.  From 
this  origin  the  fibres  of  the  sphincter  collect 
into  a  rounded  fasciculus,  which  proceeds  for- 
wards and  downwards,  increasing  in  size,  and  at 
the  back  of  the  anus  divides  into  two  bands 
which  pass  one  on  either  side  of  this  opening, 
each  spreading  out  till  it  is  an  inch  or  even 
more  in  breadth ;  again  converging  in  front  of 
the  anus,  these  bands  unite  into  a  fasciculus, 
which  in  the  male  is  very  long  and  passes  for- 
wards and  upwards  between  the  skin  and  the 
acceletatores  urinae  muscles,  to  be  partly  in- 
serted into  the  median  line  of  the  superficial 
fascia  of  the  perinaeum,  and  partly  confounded 
and  interlaced  with  the  transversi  perinaei,  and 
with  the  muscles  which  cover  the  bulb  of  the 
urethra;  through  the  medium  of  these  last 
it  is  even  attached  to  the  common  cellulo- 
tendinous  central  point  of  the  perinaeum,  be- 
tween the  rectum  and  the  bulb,  whereby  it 
is  enabled  to  act  on  this  part  of  the  urinary 
canal.  This  anterior  insertion  is  very  variable 
in  different  persons  ;  in  some  it  stops  abruptly 
at  Ihe  bulb,  while  in  others  it  continues  to  run 
forwards  between  the  skin  and  the  acceleratores 
as  far  as  the  dartos,  in  which  it  terminates.  In 
the  female  this  anterior  fasciculus  is  much 
shorter,  and  ends  in  the  sphincter  or  con- 
strictor vaginae ;  in  the  male  its  attachment  to 
the  muscles  of  the  bulb  is  often  deficient,  so 
that  in  the  course  of  the  dissection,  when  the 
superficial  fascia  has  been  removed,  this  ex- 
tremity of  the  muscle  will  be  found  detached 
and  its  insertion  isolated.  The  entire  of  the 
inferior  surface  of  this  muscle  is  in  contact  with 
the  integuments,  its  superior  surface  is  related 
to  the  levatores  ani,  acceleratores  urinae,  and 
transversi  perinaei  muscles ;  in  front  of  the 
anus  it  is  confounded  with  the  two  latter,  and 
immediately  behind  it  with  the  formerly  named 
muscles ;  its  external  border  is,  of  uncertain  ex- 
tent, and  is  imbedded  in  adeps,  while  its  inter- 
nal edge  is  in  close  relation  with  the  delicate 
inflected  anal  skin,  being  separated  only  by  a 


fine  cellular  tissue.  This  muscle  is  composed 
entirely  of  fleshy  fibres,  occasionally  intersected 
by  cellular  and  imperfect  tendinous  bands; 
these  fibres  are  placed  in  concentric  arches, 
those  of  opposite  sides  unite  at  acute  angles, 
and  sometimes  interlace  before  and  behind  the 
anus ;  the  fasciculi  are  frequently  separated  by 
considerable  intervals,  so  that  they  appear  like 
different  muscles  ;  some  of  the  internal  fibres 
assume  a  circular  arrangement ;  in  the  female 
this  muscle  is  shorter,  broader,  and  more 
rounded,  particularly  in  front.  In  structure 
and  appearance  this  muscle  presents  great 
diversity ;  in  some  it  is  red,  strong,  and  large, 
in  others,  so  pale  and  weak  as  to  be  difficult  of 
perfect  demonstration ;  it  is  also  probable  that 
during  life  great  differences  exist  as  to  its 
power  of  contraction. 

The  use  of  this  muscle  is  obviously  to  close 
the  anus,  the  skin  of  which  it  throws  into  small 
rugae  ;  hence  when  the  sphincter  is  paralysed, 
there  is  incontinence  of  the  contents  of  the  rec- 
tum ;  the  most  internal  fibres  will  tend  to  close 
the  opening  more  perfectly  than  the  external  or 
elliptical,  which  will  reduce  it  rather  to  a  cleft 
or  fissure ;  this  muscle  can  also  raise  the  anus 
somewhat,  and  at  the  same  time  draw  back  and 
compress  the  bulb  of  the  urethra;  it  will  also 
express  the  secretion  from  the  anal  glands  and 
follicles.  The  sphincter  ani  may  be  properly 
said  to  belong  to  the  class  of  mixed  muscles, 
both  as  relates  to  its  structure  and  function  ;  as 
to  the  former,  its  paleness,  scattered  fibres, 
connection  with  the  commencement  of  the  mu- 
cous surface,  and  absence  of  true  tendon  ally  it 
to  the  muscular  system  of  organic  life;  while  on 
the  other  hand  the  parallel  direction  of  its  fas- 
ciculi, and  the  arrangement  of  many  of  the 
latter  in  the  surrounding  adeps,  assimilate  it  to 
the  muscles  of  voluntary  motion.  In  its  functions 
also  it  appears  to  border  on  the  province  of  each 
division  of  the  muscular  system ;  thus  without 
the  efforts  of  the  will,  or  even  without  any  in- 
ternal cognizance,  it  continues  in  a  state  of  al- 
most permanent  contraction,  and  as  uncon- 
sciously relaxes  when  the  functions  of  the  part 
impress  upon  its  sensibility  the  necessity  of  so 
doing ;  while  on  the  other  hand  the  will  can 
exert  a  considerable  control  over  its  powers, 
and  can  cause  it  to  contract  with  considerable 
and  continued  energy,  as  well  as  throw  it  into 
a  state  of  atony  and  .relaxation.  Although  this 
muscle  belongs  to  the  same  class  with  the  other 
sphincters,  the  orbiculares  oris  and  palpebra- 
rum,  yet  it  manifests  a  considerable  difference  in 
its  vitality.  The  natural  and,  therefore,  the  usual 
condition  of  these  other  sphincters  is  relaxation ; 
hence  the  mouth  continues  open,  and  partly 
from  the  same  cause  too,  the  eyelids  are  apart ; 
whereas  the  natural  condition  of  the  sphincter 
ani  when  at  rest  is  contraction,  and  hence  the 
anal  opening  is  always  closed,  although  the 
muscle  is  still  capable  of  contracting  with  con- 
siderably more  energy  when  any  of  the  contents 
of  the  rectum  suddenly  approach  the  orifice, 
or  when  any  irritation  exists  in  its  vicinity. 

The  Sphincter  ani  internus  vel  orbicularis 
(Sphincter  infest male,  Winsl.)  is  of  much  less 
extent  than  the  former,  and  is  situated  more 


AN  IS. 


177 


deeply;  it  is  closely  connected  to  the  mucous 
membrane,  or  the  fine  lining  integument,  and 
appears  a  particular  development  of  the  circular 
fibres  of  the  intestine,  like  those  which  surround 
the  pyloric  extremity  of  the  stomach.  This  cir- 
cular muscular  ring  consists  of  several  fine  and 
pale  fasciculi  of  fibres,  which  are  closely  con- 
nected together,  and  when  contracted  form  a 
thick  ring  around  the  intestine  immediately  with- 
in the  anus ;  this  muscle  may  be  exposed  either 
by  detaching  the  lining  membrane  which  is  but 
loosely  attached  to  it,  or  removing  the  rectum 
from  the  subject,  everting  and  distending  it. 
The  mucous  membrane  being  then  detached, 
the  muscle  will  be  distinct ;  its  upper  border 
is  continuous  with  the  circular  fibres  of  the 
rectum,  and  a  distinct  cellular  line  separates  it 
from  the  cutaneous  sphincter ;  anteriorly  it  is 
connected  with  the  levatores  ani  muscles. 

The  action  of  this  muscle  must  be  to  assist 
the  former  sphincter  in  closing  the  lower  ex- 
tremity of  the  rectum  and  supporting  its  con- 
tents ;  in  the  process  of  defsecation  it  assists  in 
the  expulsion  of  the  residual  portions  of  the 
faecal  matter,  by  the  sudden  or  almost  spas- 
modic action  which  succeeds  its  relaxation ; 
moreover,  it  strongly  opposes  the  entrance  of 
any  foreign  body  by  the  anus ;  so  that  from 
its  power  of  resisting  the  ingress  or  egress  of  any 
substance,  it  may  be  considered  as  constituting 
a  perfect  pylorus. 

The  subcutaneous  adipose  tissue  in  perineo 
is  very  abundant  in  some  situations ;  close  to 
the  anus,  or  between  the  sphincter  and  the 
skin,  there  is  but  very  little ;  hence  abscesses 
but  seldom  form  there,  except  of  very  limited 
size,  such  as  small  furunculi,  or  as  the  result  of 
circumscribed  inflammation  in  some  of  the  fol- 
licles around  the  opening;  whereas  at  either 
side  of  the  anus  and  rectum  there  always  exists 
a  considerable  quantity  of  cellular  and  adipose 
matter,  the  former  remarkable  for  the  large 
size  of  its  cells,  which,  are  intersected  by  irre- 
gular bands  or  fibres  from  the  perinaeal  fascia, 
and  which  give  the  whole  some  degree  of 
elasticity ;  the  adipose  substance  is  abundant, 
very  soft,  loose,  sometimes  reddish,  and  fills 
those  large  spaces  which  exist  on  either  side  of 
the  rectum.  In  no  part  of  the  body  do  ab- 
scesses so  frequently  form  as  in  these  ischio- 
rectal  spaces ;  and  as  such  abscesses  are  very 
generally  attended  with  consequences  tedious, 
troublesome,  and  dangerous,  it  may  be  right 
to  make  a  few  remarks  on  the  anatomy  of 
these  regions. 

Each  Ischio-rectal  space  is  a  deep  triangular 
hollow,  the  base  being  situated  towards  the 
integuments,  the  apex  towards  the  cavity  of 
the  pelvis  ;  the  outer  side  is  formed  by  the 
ischium,  and  the  inner  by  the  rectum  with 
its  muscles;  this  intestine,  together  with  the 
attachments  of  the  levatores  ani  behind  and 
before,  separates  the  two  spaces  from  each 
other,  but  the  cellular  membrane  of  one  side 
communicates  with  that  of  the  opposite,  and 
hence  in  cases  of  diffused  or  extensive  suppu- 
rations, the  fluid  is  occasionally  observed  to 
pass  from  one  side  to  the  other;  anteriorly 
the  transversus  perinoei,  and  posteriorly  the 

VOL.  I. 


eoccygeus  muscles  bound  this  hollow.  Kach 
of  these  triangular  recesses  is  lined  on  all  sides, 
except  towards  the  skin,  by  fasciae,  a  view  of 
which  may  be  obtained  by  dissecting  out  of 
either  all  the  contained  adeps.  There  may 
then  be  observed  near  the  apex,  or  the  deepest 
part  of  the  recess,  a  strong  and  tense  aponeu- 
rotic  line,  which  is  the  inferior  folded  surface 
of  the  pelvic  fascia,  which  in  this  situation 
sends  oft'  its  inferior  or  descending  layer ; 
this  latter  immediately  divides  into  two  laminae, 
an  internal  and  an  external ;  the  latter  is  called 
the  obturator,  the  former  the  ischio-rectal  fascia ; 
the  former  is  very  strong  and  distinct,  the  latter 
very  thin  and  cellular. 

The  obturator  fascia  descends  a  little  ob- 
liquely outwards  and  is  inserted  into  the  falci- 
form process  of  the  great  sacro-sciatic  liga- 
ment, and  into  the  tuberosity  and  ramus  of  the 
ischium.  It  is  very  dense,  being  composed  of 
strong  aponeurotic  fibres,  and  it  conceals  and 
separates  from  the  perinseum  the  obturator  in- 
tern us  muscle,  and  the  internal  pudic  nerves 
and  vessels,  the  perinaeal  and  hemorrhoidal 
branches  of  which  pierce  it  as  they  proceed 
to  their  destination.  The  internal  layer,  or  the 
Iskio-rectal  fascia,  is  much  weaker  and  more 
cellular  than  the  last;  from  the  before-men- 
tioned aponeurotic  line  it  descends  obliquely 
inwards  along  the  lower  and  outer  surface 
of  the  levator  ani  as  far  as  the  sphincter,  when 
it  becomes  thin  and  cellular,  and  is  lost  in  the 
surrounding  adipose  tissue.  Thus,  by  the 
unfolding  or  division  of  the  inferior  layer  of 
the  pelvic  fascia  into  these  two  laminae,  the 
obturator  and  ischio-rectal  fasciae,  these  re- 
cesses are  completely  lined,  and  by  the  gradual 
degeneration  of  the  last  named  aponeurosis 
into  cellular  and  fibrous  bands,  which  inter- 
lace in  every  direction,  the  large  mass  of  adi- 
pose substance  is  enclosed  and  supported,  whilst 
a  general  firmness  and  elasticity  is  imparted 
to  the  whole  region.  Towards  the  posterior 
part  of  each  of  these  regions  a  cul  de  sac  is 
enclosed  between  these  fasciae  and  overlapped 
by  the  glutaeus  maximus,  on  the  surface  of 
which  the  fascise  become  extended,  and  ulti- 
mately lost.  A  somewhat  similar  but  smaller 
cul  de  sac  exists  anteriorly  behind  each  trans- 
versus perinaei  muscle.  An  inspection  of  the 
Ischio-rectal  spaces  will  serve  to  explain  not 
only  the  great  size  to  which  abscesses  here 
attain,  but  also  the  difficulty  in  effecting  a  cure 
when  they  have  been  of  long  standing  and  of 
considerable  magnitude  ;  the  constantly-vary- 
ing form  of  the  rectum  on  one  side,  the  im- 
moveable  surface  of  the  pelvis  on  the  opposite, 
a  muscle  above,  and  the  integuments  below, 
all  tend  to  prevent  the  possibility  of  effecting 
any  permanent  apposition  between  the  sides  of 
the  cavity,  while  very  generally  the  state  of  the 
constitution  is  equally  unfavourable  to  any 
healthy  action  in  the  part.  These  several  facts 
have  impressed  surgeons  with  the  propriety  of 
opening  all  such  abscesses  in  a  very  early 
stage,  otherwise  a  large  cavity  will  be  formed, 
the  rectum  denuded,  and  very  frequently 
opened  by  ulceration. 

Trunsversi    perintfi    muscles    ( Tachio-peri- 


178 


ANUS. 


neal). — This  pair  of  small  muscles   extends 
in  a   direction    nearly   parallel    to   the    ante- 
rior border  of  the  anal  region  ;    each   arises 
from  the   inside   of  the   tuber  ischii,  passes 
inwards,  forwards,  and  downwards  to  join  its 
fellow  in  the  median  line  of  the  perineum, 
where  it  is  also  partially  attached  to  the  cuta- 
neous sphincter  of  the  anus,  and  to  the  acce- 
leratores  urinae  muscles,  or  in  the  female  to  the 
constrictor  vaginae.     These   muscles  are  very 
unequal  in  appearance  in  different  subjects; 
in  some  they  are  feeble  and  indistinct,  in  others 
very  strong,  and  sometimes  divided  into  two 
on  one  or  both  sides,  the  additional  or  minor 
muscle  being  superior  and  anterior.      In  the 
female  these  muscles  are  often  found  more  dis- 
tinct than  in  the  male,  but  even  here  much 
variety  exists  ;  in  many  subjects  they  appear 
to  be  simply  composed  of  some  of  the  anterior 
and  partially  detached  fibres  of  the   middle 
portions  of  the   levatores  ani  muscles.     The 
transversi  perinsei  muscles  form  the  bases  of 
the  two  lateral  triangular  regions  contained  in 
the  anterior  or  urethral  perinaeum,  and   one 
of  them,   the  left,  is   necessarily  divided   in 
the  lateral  operation  for  lithotomy;  they  are 
surrounded  by  much  adipose  matter  ;  two  arte- 
ries, both  branches  of  the  internal  pudic,  take 
a  course  parallel  to  them,  —  viz.,  the  super- 
ficial transverse  perinaeal,  and  the  deep  trans- 
verse, or  the  artery  of  the  bulb.    These  muscles 
are  enveloped  between  the  layers  of  the  perinaeal 
fasciae.    The  superficial  layer,  which  is  continu- 
ous with  the  Ischio-rectal,  covers  them  in  their 
course  forwards  to  the  urethral  muscles,  and 
the  deep  layer,  or  the  triangular  ligament  of 
the  urethra,  which  is  continuous  with  the  ex- 
ternal or  Ischiatic  layer  or  obturator  fascia,  lies 
between  them  and  the  pelvis.     These  muscles, 
therefore,  will  have  the  effect  of  making  tense 
the   different  perinaeal  aponeuroses,  and  thus 
they  can  support,   strengthen,  and  compress 
generally  the  parts  in  the  perinaeum  ;  they  can 
also  compress,  and  thus  assist  in  clearing  the 
orifice  of  the  anus,  at  the  same  time  that  they 
draw  back  and  raise  this  part,  somewhat  in 
the  same  manner  as  the  levatores  ani  muscles. 
According  to  some  anatomists  these  muscles 
are  considered  as  dilators  of  the  bulb  of  the 
urethra,  as  well  as  of  the  vagina ;  but  it  is  more 
than  doubtful  whether  they  can  exert  any  such 
action.     When  these  muscles  are  divided,  the 
base  of  the  deep  perinaeal  fascia,  or  triangular 
ligament  of  the  urethra,  is  exposed.     This  will 
be  observed  to  have  some  influence  in  main- 
taining the  rectum  and  anus  in  their  situation  ; 
its  posterior  border,    being    attached   to    the 
levatores  ani  muscles,  and  to  the  bulb  of  the 
urethra,  serves  to  maintain  a  close  connection 
between  these  parts,  which  is  still  further  ef- 
fected by  the  interlacement  of  the  muscles  of 
the  anus  with  those  which  cover  the   bulb. 
(See  PERINEUM.) 

Levatores  ani  (sous-pubio-coccygien). — This 
pair  of  broad,  thin,  flat,  and  nearly  square 
muscles  form  a  septum  somewhat  broader 
above  than  below,  between  the  pelvis  and 
perinaeum,  which,  together  with  the  aponeu- 
roses covering  its  upper  and  lower  surfaces, 


and  with  the  coccygeal  muscles  and  the  trian- 
gular ligament  of  the  urethra,  completely  in- 
tercepts all  communication  between  these  two 
regions   except    through  the   natural  passages 
for  the  urethra,  vagina,  and  rectum.     Although 
these  muscles  are  described  as  two,  there  ap- 
pears no  good  reason  for  the  division,  for  the 
fibres  of  opposite  sides  have  a  common  in- 
sertion,  partly   into  the  circumference  of  the 
rectum  and  partly  into  a  middle  cellulo-ten- 
dinous  raphe  before  and  behind  that  intestine. 
It  appears  more  correct  to  consider  these  muscles 
as  one  circular  muscular  septum  extended  across 
arid  within  the  lower  opening  of  the  pelvis, 
concave  towards  this  cavity,  and  convex  to- 
wards the  perinaeum.     The  fibres  attached  by 
their  circumference  to  the  interior  of  the  pelvis, 
and  converging  thence  towards  the  median  line 
of  the  perinaeum,  are  inserted  into  and  around 
the  rectum  ;  in  fact  the  muscle  resembles  the 
diaphragm  in  form,  in  the  circumference  being 
its  origin  or  fixed  attachment,  and  the  central 
portion  being  its  insertion,  also  in  its  being 
perforated  for  the  transmission  of  certain  parts ; 
the   analogy  only  fails  in   the  absence  of  a 
central  tendon,  and  in  the  fibres  being  prin- 
cipally inserted  into  the  parts  passing  through 
it.     The  fact,  however,  of  there  being  an  inter- 
ruption in   the  origin  of  this  muscle  in  the 
middle  line  both  before  and  behind,  in  which 
respect  again   there  is   a  resemblance  to  the 
sternal  and  vertebral  deficiences   in  the  dia- 
phragm, is  the  cause  of  its  being  described  as 
consisting  of  a  right  and  left  muscle,  which  dis- 
tinction, it   should   be  observed,   is   only   an 
artificial  one,  for  during  life  the  fibres  of  both 
sides  act  together,  and  in  all  respects  constitute 
but  a  single  muscle. 

The  origin  of  the  levator  ani  muscle  may  be 
exposed  by  tearing  the  peritonaeum  from  the 
parietes  of  the  pelvis,  together  with  a  con- 
siderable quantity  of  loose  cellulo-adipose 
membrane.  The  recto-vesical  layer  of  the  pel- 
vic fascia  should  then  be  divided  near  to  the 
neck  and  sides  of  the  bladder,  and  carefully 
raised  towards  the  wall  of  the  pelvis.  The 
muscle  will  then  be  seen  to  arise  on  each  side 
by  three  attachments,  which,  however,  form  one 
continuous  semicircular  line  extending  from 
the  pubis  to  the  spine  of  the  Ischium;  its 
anterior  portion  is  attached  to  the  back  part  of 
the  pubis,  a  little  above  its  arch,  and  imme- 
diately below  the  anterior  vesical  ligaments  by 
short  aponeurotic  fibres  commencing  a  little 
distance  from  the  symphysis,  and  extending 
outwards  as  far  as  the  notch  in  the  thyroid 
hole ;  its  second  or  middle  attachment  is  to 
a  strong  tendinous  arch,  which  extends  from 
the  pubis  to  the  spine  of  the  Ischium,  and 
which  is  formed  at  the  separation  or  junction 
of  the  pelvic  fascia  into  its  superior  or  recto- 
vesical  layer,  and  its  inferior  or  perinaeal  layer ; 
its  third  or  posterior  attachment  is  to  the  spinous 
process  of  the  ischium.  All  the  fibres  pass 
downwards  and  towards  the  median  line  to 
their  insertion ;  the  inferior  border  of  this 
muscle  is  shorter  but  thicker  than  the  superior. 
The  fibres  of  the  first,  or  pubal  portion,  des- 
cend a  little  obliquely  backwards  on  each  side 


ANUS. 


179 


of  the  prostate  gland  and  membranous  portion 
of  the  urethra,  and  converging  beneath  the 
latter  are  inserted  in  common  between  the  bulb 
and  the  fore-part  of  the  rectum  into  the  central 
point  of  the  perinaeum  ;  these  portions  in  their 
descent  present  a  well-defined  edge  inwards  or 
towards  the  median  line.  The  middle,  or 
aponeurotic  portion,  is  broad  and  thin  above, 
the  vesical  fascia  adhering  so  closely  to  it  as  to 
render  its  separation  difficult.  As  it  descends 
it  increases  in  thickness,  expands  close  to  the 
rectum,  and  is  inserted  into  the  coats  of  that 
intestine,  intermingling  with  its  longitudinal, 
fibres,  and  with  the  sphincter  ani ;  in  the  female 
it  is  intimately  attached  to  the  vagina  also. 
The  posterior  or  Ischiatic  portion  passes  al- 
most transversely  inwards,  and  is  inserted  into 
the  coccyx,  and  into  the  cellulo-tendinous  line 
which  extends  from  the  latter  to  the  rectum ; 
some  fleshy  fibres  are  continuous  from  one 
muscle  to  the  other.  This  portion  of  the  le- 
vator  ani  is  more  aponeurotic  than  the  pre- 
ceding, and  its  posterior  border  is  connected  to 
the  Ischio-coccygaeus  muscle.  The  external  or 
inferior  surface  of  this  muscle  is  inclined  down- 
wards, and  is  more  or  less  related  to  the  obtu- 
rator and  ischio-rectal  fasciae,  to  the  glutaeus 
maxim  us  and  transverse  perinaeal  muscles  and 
vessels,  and  to  the  mass  of  anal  fat.  The 
internal  or  concave  surface  looks  upwards,  and 
is  closely  covered  by  the  vesical  fascia,  below 
which  it  is  in  contact  with  the  rectum,  bladder, 
prostate  gland,  and  urethra,  or  with  the  uterus 
and  vagina.  This  muscle  is  disposed  on  the 
rectum  in  the  same  manner  in  the  female 
as  it  is  in  the  male;  the  fibres  are  also  inti- 
mately connected  to  the  vagina. 

The  action  of  the  levator  ani  muscles  is 
two-fold,  and  not  confined  to  the  mere  ele- 
vation of  the  anus,  as  its  name  would  im- 
ply. First,  they  act  as  a  moveable  floor  to 
the  abdomen  and  pelvis,  which  can  antago- 
nize the  diaphragm ;  these  two  fleshy  planes 
being  opposed  to  each  other,  can,  by  a  slight 
action  of  one  or  both,  materially  alter  the 
perpendicular  axis  of  the  abdomen,  which 
extends  between  them.  This  axis  is  at  its  great- 
est length  during  the  state  of  expiration,  and  is 
most  diminished  when  both  these  muscles  are 
forcibly  contracting.  The  levatores  ani,  how- 
ever, have  less  influence  in  effecting  this  change 
than  the  diaphragm ;  they  serve  chiefly  to 
support  the  lower  region  of  the  pelvis  and  the 
several  viscera  this  cavity  contains  against  the 
combined  protruding  forces  of  the  diaphragm 
and  abdominal  muscles  in  violent  exertions  of 
the  body,  or  in  forcible  efforts  of  respiration, 
or  in  the  evacuation  of  the  contents  of  the  rec- 
tum and  bladder ;  and,  secondly,  they  not 
only  raise,  but  dilate  the  anus,  by  drawing  out 
its  circumference  so  as  to  overcome  the  sphinc- 
ters ;  at  the  same  time  they  compress  and 
assist  in  emptying  the  rectum,  particularly  the 
dilated  pouch,  which  is  a  little  above  the  anus; 
they  also  resist  the  prolapsus  of  the  mucous 
coat  of  the  intestine,  and  raise  it  after  it  has 
been  to  a  certain  extent  protruded  by  the  action 
of  the  abdominal  muscles.  They  raise  and  draw 
forward  the  coccvx  after  it  has  been  forced  back 


by  abdominal  pressure  in  parturition,  or  in  the 
ordinary  evacuation  of  the  bowels,  and  further, 
by  raising  and  compressing  the  trigone  of  the 
bladder,  they  assist  in  expelling  its  contents, 
and  for  the  same  reason  they  can  also  empty  the 
vesiculae  seminales  of  their  fluid.  The  anterior 
portions  of  these  muscles  are  intimately  con- 
nected to  the  membranous  part  of  the  urethra, 
and  are  variously  modified  in  different  indi- 
viduals and  in  different  animals;  we  consider 
those  muscular  fasciculi  which  have  been  de- 
scribed differently  by  anatomical  writers  under 
different  names,  compressores  urethrae,  &c.,  as 
parts  of  or  appendages  to  these  muscles  :  these 
urethral  portions  of  the  levatores  ani  can  cer- 
tainly compress  the  membranous  part  of  the 
urethra  and  empty  its  canal  ;  they  can  even 
interrupt  or  suddenly  stop  the  stream  of  urine, 
and  thus  they  may  occasionally  aid  the  neck  of 
the  bladder  in  retaining  the  contents  of  that 
organ. 

The  Ischio-cocct/gcei  muscles  are  situated  at 
the  posterior  inferior  part  of  the  pelvis ;  they 
are  thin,  flat,  and  triangular,  composed  of  a  mix- 
ture of  fleshy  and  tendinous  fibres.     The  apex 
or  origin  of  each  is  attached  to  the  spine  of  the 
Ischium,  and  its  base  is  inserted  into  all  the  side 
of  the   coccyx,  and  a  small  portion  of  the 
sacrum  ;  they  are  partly  covered  by  the  great 
sciatic  ligaments.     The  superior  and  posterior 
border  is  connected  to  the  lesser  sciatic  liga- 
ment, and  the  anterior  border  is  in  part  con- 
tinuous with  the  levator  ani  muscle ;  the  an- 
terior or  pelvic  surface  is  connected  to  the 
rectum  and  the  surrounding  adipose  substance. 
This  pair  of  muscles  appear  as  a  prolongation 
of  the  levatores  ani,  and  are  of  use  in  com- 
pleting the  inferior  boundary  of  the  pelvis; 
they  thus  support  the  rectum  and  the  pelvic 
viscera,  and  they  also  serve  to  retain  the  coccyx 
and  restore  it  to  its  situation  when  protruded  by 
the  diaphragm  and  abdominal  muscles  in  the  pro- 
cess of  parturition,  and  in  the  act  of  defalcation, 
or  when  drawn  too  much  forward  by  the  levatores 
ani  muscles.     If  the  several  muscles  in  this 
region  be  now  partially  removed  on  one  side, 
the  lower  extremity  of  the  rectum  will  become 
more  distinct,  and  will  be  found  surrounded  by 
a  quantity  of  loose,  fatty,  cellular  tissue,  sepa- 
rating it  from  the  surrounding  muscles  and 
bones;  this  contains  many  nervous  filaments 
and  numerous  bloodvessels,  particularly  veins. 
(See  INTESTINAL  CANAL.)     Anteriorly  in  the 
male    subject  a  small   triangular   space,   the 
bulbo-rectal  hollow,  will  now  become  distinct ; 
this  is  situated  between  the  anus  and  mem- 
branous portion  of  the  urethra ;  the  base  of  it 
is  at  the  skin  of  the  perinaeum ;  the  apex  at 
the  prostate :  to  the  last  the  rectum  will   be 
seen  rather  intimately  connected.  The  bulb  and 
the  membranous  portion  of  the  urethra  bound 
this  space  in  front,  and  the  rectum   behind. 
(See  PERINEUM  and  URETHRA.) 

Rectum.—  In  addition  to  the  several  muscles 
which  have  now  been  severally  noticed,  and 
which  thus  serve  not  only  to  retain  and  support 
the  rectum  and  anus,  but  which  even  enter  into 
the  structure  of  the  former,  we  have  further  to 
consider  the  parts  more  immediately  composing- 


180 


ANUS. 


the  parietes  of  the  lower  extremity  of  the  in- 
testine;  these  are  the  longitudinal  muscular 
fibres,— the  mucous  membrane,  and  the  sub- 
mucous  cellular  tissue.  The  longitudinal  fibres 
of  the  alimentary  tube  exist  through  its  whole 
extent,  but  like  the  circular  are  differently  mo- 
dified in  different  situations;  thus  along  the  oeso- 
phagus they  are  very  fully  developed,  also  along 
the  arches  of  the  stomach;  in  both  these  situa- 
tions the  fibres  are  strong  and  somewhat  red ; 
whereas  on  the  parietes  of  the  small  intestines 
they  are  very  indistinct  and  pale ;  on  the  coecum 
and  colon  they  are  still  pale,  but  very  distinct, 
being  collected  into  three  flat  fasciculi  or  bands. 
On  the  rectum,  as  on  the  oesophagus,  they  are 
again  fully  developed  as  to  thickness  and  num- 
ber ;  their  colour  is  still  rather  pale.  In  the 
two  superior  thirds  of  this  intestine,  or  as  low 
down  as  the  prostate  gland,  they  predominate 
over  the  circular  fibres,  which  are  internal, 
whereas  in  the  lower  third  the  latter  prevail; 
the  former  terminate,  some  by  becoming  con- 
tinuous or  intermingled  with  the  fibres  of  the 
levatores  ani,  others  with  the  cutaneous  sphinc- 
ter so  low  as  the  border  of  the  anus,  and  some 
are  inserted  into  the  submucous  tissue  of  the 
intestine ;  these  fibres  are  continuous  superiorly 
With  those  of  the  colon ;  they  serve  to  continue 
that  successive  series  of  contractions  or  shorten- 
ings of  the  intestine,  which  essentially  assist  in 
the  process  of  defaecation.  As  the  longitudinal 
fibres  of  the  rectum  resemble  those  of  the  oeso- 
phagus, so  the  inferior  circular  fasciculi  or  the 
sphincters  are  like  the  muscles  of  the  pharynx, 
not  merely  in  their  increased  strength  and  colour, 
but  also  in  their  vital  power.  Over  the  lon- 
gitudinal fibres  the  will  lias  no  control,  whereas 
the  inferior  circular  are  to  a  certain  extent  under 
its  influence.  Here,  then,  as  in  the  organs  of 
deglutition,  we  perceive  the  animal  and  organic 
powers  still  distinct  as  to  their  elementary  na- 
ture, but  becoming  intimately,  nay  inseparably 
associated  for  wise  and  obvious  purposes. 

In  the  act  of  defaecation  the  offices  of  the  se- 
veral muscles  connected  with  the  anus  may  be 
summed  up  as  follows : — When  the  contents 
of  the  rectum,  particularly  if  of  a  solid  con- 
sistence, are  being  expelled,  the  whole  rectum 
descends,  and  the  perinaeum  becomes  promi- 
nent in  consequence  of  the  viscera  being  forced 
against  it  by  the  contraction  of  the  diaphragm 
and  abdominal  muscles.  The  presence  of  the 
faeces  irritates  the  muscular  fibres  of  the  rectum; 
the  longitudinal  fibres  shorten  the  intestine, 
while  the  successive  actions  of  the  circular 
urge  down  the  faecal  mass;  these  two  orders 
of  muscular  fibres  are  the  true  antagonists  to 
the  sphincters.  During  this  stage,  however, 
the  sphincters  are  relaxed,  and  the  anus  be- 
comes dilated,  partly  by  the  contents  of  the  rec- 
tum distending  it,  ana  partly  by  the  levatores 
ani  muscles,  which  are  nevertheless  in  a  suffi- 
ciently relaxed  condition  to  allow  the  protru- 
sion of  the  rectum  and  anus,  while  they  still 
support  the  latter  to  a  certain  extent,  and  thus 
exert  a  sort  of  check  against  its  forcible  de- 
scent ;  they  also  tend  to  open  the  orifice  of 
the  anus.  During  this  forcible  expulsion,  a 
small  portion  of  the  mucous  lining  is  frequently 


protruded.  The  expulsion  of  the  last  portion 
of  faeculent  matter  is  then  effected  by  the  sub- 
sequent strong  and  gradual  contraction  of  the 
levatores  ani  compressing  the  rectal  pouch,  and 
raising  the  rectum  and  anus  to  their  former 
position,  and  lastly,  the  sudden  action  of  the 
sphincters  clears  and  closes  the  orifice. 

The  mucous  membrane  lining  the  rectum  is 
in  every  respect  highly  organized,  it  is  thrown 
into  several  folds,  and  is  larger  and  looser 
than  the  other  coats,  hence  portions  can  be 
easily  removed  by  operation,  and  are  not 
unfrequently  detached  by  gangrene.  As  it 
approaches  the  anus,  it  is  very  red,  soft,  and 
fungous,  being  highly  vascular,  presenting  the 
orifices  of  several  glands,  follicles,  or  lacunas. 
It  is  here  very  loosely  connected  to  the  muscu- 
lar fibres,  and  is  frequently  found  thrown  into 
irregular  folds ;  these  are  protruded  somewhat 
during  defaecation,  and  when  morbidly  enlarged 
or  thickened,  are  not  unfrequently  the  source 
of  considerable  pain  and  inconvenience.  As  the 
mucous  membrane  is  not  contractile,  these  folds 
are  necessarily  increased  when  the  longitudinal 
fibres  of  the  rectum  contract  and  shorten  the 
intestine;  they  are  then  protruded  together 
with  the  faecal  matter.  Immediately  above  the 
plaited  margin  of  the  anus  the  skin  and  mu- 
cous membrane  become  continuous  ;  the  ter- 
mination of  the  cuticle  appears  rather  abrupt, 
just  within  the  internal  sphincter.  Some  de- 
scribe it  as  continued  higher  up,  and  gradually 
lost  on  the  surface.  I  have  not  been  able  to 
exhibit  it  satisfactorily  higher  than  the  point 
indicated,  nor  does  it  appear  to  me  that  it 
extends  through  this  orifice  by  any  means  to 
the  same  extent  as  through  the  other  outlets 
of  the  body,  the  mouth,  nose,  urethra,  or  va- 
gina. In  the  latter  passage  in  particular  'it 
is  very  distinct,  even  in  health  ;  and  in  disease, 
as  in  cases  of  prolapsus  uteri,  its  develop- 
ment becomes  considerable;  whereas  in  pro- 
lapsus ani,  that  is,  a  protrusion  of  the  mucous 
lining  of  the  rectum,  at  a  little  distance  above 
the  anus,  I  have  not  found  the  protruded 
mass  to  become  covered  with  cuticle :  I  have 
seen  cases  of  long  standing  in  which  the  surface 
presented  the  same  soft,  vascular  tissue  as  it 
does  at  first.  It  does  not  controvert  this  state- 
ment to  find  tumours  about  the  margin  of  the 
anus  (hemorrhoids  or  polypi)  covered  with  a 
thickened  or  developed  cuticle;  for  in  such 
cases  the  cutaneous  covering  is  derived  from 
the  elongation  of  the  surrounding  skin,  which 
has  increased  in  density  from  exposure  to  the 
air,  and  from  continued  irritation.  The  same 
remark  will  apply  to  cases  of  artificial  anus, 
no  matter  in  what  situation  :  in  all  these  the 
villous  surface,  which  protrudes  during  the 
peristaltic  acton,  retains  its  mucous  charac- 
ters, and  does  not  become  covered  with  cu- 
ticle. From  these  facts  it  may  be  inferred 
that  cuticle  is  never  developed  in  any  situation 
in  which  it  did  not  originally  exist,  but  that 
circumstances  favour  the  increase  or  more  full 
development  of  it  in  those  situations  where  it 
naturally  occurs,  even  though  its  normal  con- 
dition be  extremely  delicate  and  fine. 

nd  vessels. — The  submucous  tissue 


ANUS. 


181 


in  the  vicinity  of  the  anus  is  very  loose,  and  the 
seat  of  nervous  and  vascular  plexuses ;  in  the 
latter  the  venous  system  predominates. 

A  consideration  of  the  functions  of  the  rec- 
tum and  of  its  surrounding  muscles,  its  re- 
markable irritability  and  sensibility  in  health, 
as  well  as  its  sympathies  in  disease,  would  lead 
us  to  infer  what  dissection  proves  to  exist, 
namely,  that  this  organ  is  largely  supplied  with 
neives;  numerous  branches  are  furnished  to  it 
from  the  sacral  plexus,  which  is  formed  by  the 
union  of  the  inferior  spinal  nerves,  also  from 
the  hypogastric  plexus,  which  is  chiefly  com- 
posed of  filaments  of  the  sympathetic.  The 
sacral  plexus  of  spinal  nerves  furnishes,  in 
addition  to  many  others,  the  hemorrhoidal, 
vesical,  and  pudic  branches ;  the  hemorrhoidal 
nerves  are  directed  principally  towards  the  in- 
ferior part  of  the  rectum,  some  ascend  to  the 
colon,  others  descend  even  to  the  sphincter 
ani :  they  divide  into  numerous  filaments, 
which  are  chiefly  distributed  to  the  muscular 
fibres  of  the  rectum  and  the  adjacent  muscles; 
the  vesical  nerves  in  their  course  to  the  bladder 
give  some  filaments  to  the  rectum,  and  the  in- 
ferior or  perinaeal  division  of  the  pudic  nerves 
also  send  several  branches  to  the  levator  and 
sphincter  ani  muscles.  The  ht/pogastric  plexus 
of  nerves  is  composed  of  filaments  from  the 
sacral  plexus,  which  interlace  with  some  from 
the  inferior  rnesenteric  plexus,  and  with  nume- 
rous branches  from  the  sacral  ganglions  of  the 
sympathetic  nerves.  This  plexus  supplies  the 
rectum,  as  also  the  other  pelvic  viscera;  the 
branches  accompany  the  bloodvessels,  and  are 
distributed  principally  to  the  mucous  and  sub- 
mucous  tissue.  The  cellular  tissue,  also,  about 
the  coccyx,  and  the  adjacent  muscular  fibres 
receive  some  filaments  from  the  coccygeal  plexus 
of  the  sympathetic.  This  supply  of  nerves 
from  these  two  very  different  sources,  the  one 
presiding  over  voluntary,  the  other  over  in- 
voluntary motion,  corresponds  with  the  well- 
known  functions  of  this  organ,  and  causes  its 
muscles  to  be  classed  by  the  physiologist  under 
the  head  of  mixed  muscles,  that  is,  partaking 
of  the  common  characters  of  the  animal  or 
voluntary,  and  the  organic  or  involuntary  sys- 
tems. Its  supply  of  spinal  nerves  serves  to 
explain  not  only  the  influence  which  the  will  can 
exert  over  its  functions,  but  also  the  impaired 
or  altered  state  of  its  powers  in  case  of  disease 
or  injury  of  the  brain  or  spinal  cord  ;  thus  irrita- 
tion of  the  latter  may  cause  morbid  irritability 
and  contraction  of  the  rectum,  and,  necessarily, 
constipation  of  the  bowels;  or,  again,  paralysis 
of  the  spinal  cord  from  injury  or  compression 
may  lead  to  perfect  atony  of  the  sphincters,  and 
to  the  involuntary  discharge  of  the  contents  of 
the  rectum.  The  general  distribution  of  the 
branches  of  the  sacral  and  hypogastric  plexuses 
to  the  several  pelvic  viscera,  and  to  the  muscles, 
&c.  in  the  perinseum,  associates  these  different 
organs  with  each  other,  which  is  so  necessary  to 
their  functions,  and  with  the  urinary  and  genera- 
tive organs,  connecting  more  particularly  the 
muscles  of  the  anus  with  the  muscular  coat  of 
the  urinary  bladder  and  with  the  parts  about 


its  cervix.  This  interlacement  and  subsequent 
general  distribution  of  these  nerves  serve  also 
to  establish  those  several  sympathies  which  are 
found  to  exist  in  acute  and  chronic  diseases  of 
the  rectum  and  anus,  between  this  intestine  and 
the  other  pelvic  viscera.  In  some  the  uterus 
and  vagina  partake  of  the  irritation,  in  others 
the  urinary  bladder  is  almost  incessantly  irri- 
tated to  expel  its  contents ;  or,  on  the  other 
hand,  when  the  sympathetic  irritation  engages 
its  cervix  and  the  parts  in  its  vicinity,  the 
most  painful  retention  of  urine  is  endured. 
Chronic  disease  of  this  intestine  is  also  very 
generally  attended  with  occasional  attacks  of 
pain  and  irritation  in  different  portions  of  the 
alimentary  canal,  as  also  with  pain  in  the 
sacrum  and  loins,  and  in  various  other  direc- 
tions, which  may  in  most  cases  be  explained  by 
referring  them  to  nervous  irritation  extending  in 
the  course  of  some  of  the  nervous  communica- 
tions which  are  found  to  exist  in  such  num- 
bers in  the  pelvis. 

The  rectum,  like  the  rest  of  the  alimentary 
canal,  is  freely  supplied  with  blood.  Its  arte- 
ries are  named  h(emorrhoidal,  and  are  derived 
from  three  sources,  viz.,  the  abdominal  aorta, 
the  internal  iliac,  and  the  internal  pudic  arte- 
ries. The  superior  hsemorrhoidal  is  the  con- 
tinuation of  the  inferior  mesenteric,  a  branch  of 
the  aorta ;  the  middle  hemorrhoidal  is  derived 
either  from  the  internal  iliac  or  from  some  of 
its  branches ;  and  the  inferior  or  external  he- 
morrhoidal branches  from  the  perinseal  division 
of  the  pudic.  The  latter  are  destined  directly 
to  the  confines  of  the  anus,  and  are  lodged  in 
the  subcutaneous  adeps.  The  two  former  be- 
long properly  to  the  rectum,  and  are  above  the 
levatores  ani  muscles.  These  arteries  divide 
into  several  small  branches,  which  anastomose 
together,  and  form  a  continued  chain  of  inos- 
culations along  this  intestine,  somewhat  similar 
to  that  which  is  continued  along  the  whole  of 
the  alimentary  tube.  They  form  a  complicated 
vascular  net-work  between  and  within  the  mus- 
cular fibres,  and  are  largely  distributed  to  the 
mucous  and  submucous  tissues.  Some  branches 
of  considerable  size  not  unfrequently  descend 
so  low  even  as  the  sphincter,  particularly  at  its 
posterior  parts.  These  are  liable  to  be  divided 
in  operations  for  the  cure  of  fistulae,  and  some- 
times give  rise  to  a  haemorrhage,  troublesome 
and  difficult  to  restrain.  In  such  operations  the 
external  hsemorrhoidal  arteries  also  are  very 
commonly  opened,  and  bleed  smartly ;  they  can 
be  secured,  however,  with  much  less  difficulty 
than  the  divided  extremities  of  the  superior  or 
middle  haemorrhoidal  vessels. 

The  whole  of  the  rectum,  particularly  its 
lower  portion,  is  encompassed  by  numerous 
veins,  which  in  some  persons  are  very  large 
and  plexiform.  In  the  perinacum,  also,  many 
venous  plexuses  are  found  in  the  subcutaneous 
adeps.  The  external  haemorrhoidal  arteries 
have  their  external  venae  comites,  which  run 
outwardly  to  end  in  the  internal  pudic  veins 
(branches  of  the  internal  iliac).  Some  of  their 
branches  ramify  around  the  anus,  and  in  some 
cases  form  a  plexus,  in  which  hrcmorrhoidal 


182 


ANUS. 


tumours  are  frequently  developed;  the  mid- 
dle haemorrhoidal  veins  are  uncertain  as  to 
number,  size,  and  situation,  but  the  superior 
are  very  large  and  numerous;  their  branches 
form  repeated  anastomoses  in  the  submucous 
tissue  around  the  intestine,  and  frequently 
present  all  the  appearance  of  erectile  tissue, 
particularly  in  front,  communicating  below 
with  the  perinaeal  veins,  before  with  a  plexus 
of  vaginal  or  prostatic  veins,  and  above  with 
the  trunk  of  the  inferior  mesenteric  which 
leads  to  the  vena  portae.  This  latter  communi- 
cation, as  also  the  absence  of  valves  in  the 
portal  system,  has  laid  the  foundation  of  the 
practice  of  applying  leeches  to  the  anal  region 
in  chronic  inflammatory  affections  of  the  liver 
and  bowels.  The  same  facts  also  have  been 
adduced  to  explain  the  frequency  of  haemor- 
rhoids, varices,  and  vascular  congestion  about 
the  anus  and  rectum  in  cases  of  diseased  and 
hardened  liver,  which,  under  such  circum- 
stances, is  supposed  to  obstruct  the  circulation 
by  impeding  the  returning  blood  through  the 
venae  portae. 

ABNORMAL     CONDITION     OF     THE     ANUS      AND 
NEIGHBOURING    PARTS. 

Congenital  malformations. — The  lower  ex- 
tremity of  the  rectum  and  anus  not  unfre- 
quently  present  in  the  new-born  foetus  con- 
genital malformations,  some  of  which  are  in- 
compatible with  continued  existence,  while 
others  admit  of  protracted  suffering,  with  great 
inconvenience  and  imminent  danger  to  life; 
while,  again,  some  may  be  relieved  by  the  in- 
terference of  art.  Hence  it  is  necessary  to  con- 
sider these  anomalous  appearances  with  a  view 
to  discriminate  those  which  are  curable  from 
those  in  which  all  remedial  attempts  are  totally 
useless.  The  following  congenital  malforma- 
tions have  been  noticed  by  surgical  writers, 
some  of  which  have  come  under  our  own  ob- 
servation. 

\.  The  anus  has  appeared  at  first  view  to  be 
natural,  but  on  a  more  accurate  examination 
no  canal  has  been  found  above  it;  and  after 
death  it  was  discovered  that  the  rectum  was 
absent,  that  the  left  colon  ended  in  a  cul  de 
sac,  and  that  a  dense  fatty  substance  occupied 
the  situation  of  the  rest  of  the  canal.  It  is  plain 
that  no  operative  interference  could  avail  in 
such  a  case.  In  some  cases  of  this  want  of 
rectum  the  anus  has  been  absent  also.* 

2.  The  anus  and  rectum  have  appeared 
natural,  but  after  death  it  has  been  found  that 
the  latter  was  interrupted  in  one  part  of  its 
course,  and  that  the  intestine  had  ended  above 
that  in  a  cul  de  sac.  This  state  of  parts  must 
lead  to  the  same  practical  conclusion  as  that 
last  mentioned.  In  these  and  in  such  like  cases 
of  unhappy  malformation,  some  have  suggested, 
as  a  "  dernier  resort,"  the  propriety  of  opening 
the  intestinal  canal  at  some  point  in  the  abdo- 
men, so  as  to  evacuate  its  contents  and  establish 
permanently  an  artificial  anus.  The  proposal 
was  first  made  by  Littre,f  of  opening  the 

*  See  Diet,  dcs  Sciences  Med.  t.  xxiv.  p.  129. 
t  Mem.  de  FAcadem.  des  Sciences,  1720. 


sigmoid  flexure  of  the  colon  in  the  left  iliac 
region.  A  successful  case  of  this  operation  is 
recorded  as  having  been  performed  by  Duset* 
on  a  boy  twenty-four  hours  after  birth :  the 
child  was  reported,  at  twelve  years  of  age,  to 
be  in  good  health,  with  an  artificial  anus  esta- 
blished in  the  left  iliac  fossa.f 

3.  No  anus,  but  the  rectum  has  opened  into, 
and  its  contents  escaped  either  by  the  urethra 
in  the  male,  or  by  the  vagina  in  the  female. 
This   condition    is    an   approximation   to   the 
cloaca  of  birds,  and  of  some  fishes.     Life  may 
continue  under  such  an  arrangement,  particu- 
larly in  the  female,  when  the  intestine  opens 
into  the  vagina,  with  great  inconvenience  no 
doubt ;  but  in  the  male  the  prognosis  cannot 
even  be    so   favourable,    as  the   urethra    can 
scarcely  suffice  to  give  exit  to  the  faeces  after 
some  time ;  and  as  the  bladder  and  organs  in 
its  vicinity  will  be  subject  to  constant  irrita- 
tion.     Cases   are,  however,  recorded   of  life 
being  protracted  for  several  months;  and  in 
one  case,  a  boy,  who  lived  for  eight  months, 
on  examination  after  death  it  was  found  that  a 
cherry-stone  had  blocked   up  the  passage  of 
communication  between  the  rectum  and  ure- 
thra.    In  such  a  state  of  parts  it  has  been  ad- 
vised to  cut  through  the  perinaeum  in  the  situa- 
tion of  the  anus,  and  endeavour  to  open  the 
extremity  of  the  rectum.    The  bladder  should 
be  previously  emptied  of  urine,  and  a  sound 
or  staff  be  retained  in  it,  as  a  guide  to  the 
operator  to   protect  it  from   injury.      In  the 
other    somewhat  parallel   condition    of   these 
parts  in  the  female,  the  exit  for  the  alvine  mat- 
ters is  usually  more  free ;  and  several  cases  are 
on  record  of  life  being  continued  for  several 
years.     These  cases  offer  more  encouragement 
for  operative  interference  than  the  former.     A 
curved  probe  may  be  passed  from  the  orifice 
in  the  vagina  into  the  rectum,  and  then  directed 
towards  the  perinaeum  to  the  situation  of  the 
anus.     An  incision  is  to  be  then  made  upon 
it ;  and  when  the  canal  of  the  rectum  is  thus 
opened  to  the  surface,  the  channel  is  to  be  kept 
carefully  dilated,  in  order  to  oppose  the  natural 
tendency  in  the  parts  to  close. 

4.  The  anus   may  be  open,  but  the  con- 
tents of  the  intestine  retained,  in  consequence 
of  a  congenital  contraction  of  the  rectum  at 
some  distance  above,  owing  either  to  a  mem- 
branous septum  extending  across  it,  or  to  a 
circular  thickening  and  contraction.    Such  cases 
may  be  overlooked,  and   their  cause   remain 
unknown  until  after  death  :  in  cases,  therefore, 
of  obstinate  constipation  at  this  early  age,  this 
part  should  be  particularly  examined.     Petit  J 
describes  this  condition,  and  mentions  a  case 
in  which  he  detected  such  an  obstruction  in  the 
rectum,  about  an  inch  above  the  anus.    This 
he  divided  by  a  pharyngotome,  with  success. 
The  division  may  be  effected  by  a  bistoury,  if 
situated  low  down ;    or  by  a  trochar,  if  at  a 
considerable  distance  from  the  anus. 

*  Recueil  Periodiqtie  de  la  Societe  de  Med.  de 
Paris,  t.  iv.  p,  45. 

t  Diet,  des  Sciences  Med.  t.  xxiv.  p.  126. 
f  Mem.  de  FAcad.  de  Chirurg.  t.  i.  p.  385. 


AM  S. 


183 


5.  No  anus,  but  the   rectum  is  continued 
pervious  as   far  as  the  integuments,  which  in 
some  cases  are  then  prominent,  and  of  a  violet 
colour,  from  the  meconium  appearing  through 
in  the  siiuation  which  the  anal  opening  should 
occupy.  In  other  cases  the  skin  is  thick  and  hard, 
and  gives  no  indication  of  the  situation  of  the 
rectum.  In  such  circumstances  the  surgeon  must 
divide  the  integuments,  either  by  a  crucial  or  by 
a  transverse  and  longitudinal  incision,  and  then 
proceed  cautiously  until  he   exposes   the  dis- 
tended  rectum.      When  the  skin  only  inter- 
venes, the  prognosis  as  to  the  result  of  this 
operation  may  be  favourable,  as  the  sphincters 
are  probably  perfect ;  but  when  the  cul-de-sac 
of  the  rectum  is  deep-seated,  then  experience 
affords  but  little  encouragement  to  hope  for 
success.     Death   is  inevitable   in   such  cases, 
unless  relief  can  be  afforded,  and  but  very  few 
cases  of  successful  operations  are  on  record.* 
6.  The  anus  and  the  continuous  portion  of 
the   rectum  are  so  contracted  as   scarcely   to 
admit  of  any  fluid  discharge :  we  have  even  seen 
it  scarcely  pervious  to  air,  so  that  on  forcing  in 
a  grooved  director,  a  considerable  burst  of  flatus 
has  escaped.     This  contraction  may  exist  be- 
low, and  yet  the  rectum  be  perfectly  natural 
above.      This   contraction   is   sometimes    not 
sufficiently  noticed  for  several  days  or  perhaps 
weeks  after  birth,  because  occasionally  there  is 
a  small  discharge  of  fecal  matter ;  it  ultimately, 
however,  excites  attention  from   the  great  diffi- 
culty, straining,  pain,  and   crying   manifested 
at   each   evacuation.     This    condition  of   the 
parts  sometimes  admits  of  relief,  by  simple 
dilatation,  by   introducing  a   soft  bougie,   or 
some  prepared   sponge,  which  should  be  re- 
placed after  each  evacuation,  and  secured,  if 
possible,  by  adhesive  plaster  and  a  bandage. 
Should  these  means  fail,  an  effectual  cure  may 
be  obtained,  as  we  have  seen,  by  a  division  of 
the  circumference.    This  may  be  done  by  intro- 
ducing into  the  rectum  a  button-pointed  bis- 
toury  for  about  an   inch  on   a  director,  and 
dividing  the  wall  of  the  intestine  transversely, 
towards  the  ischium,  first  on  one  side,  and  then 
on  the  other,  to  the  depth  of  about  one  quarter 
of  an  inch.   The  part  must  be  carefully  dressed, 
and  the  edges  of  each  wound  kept  separate  by 
lint.     The  success  of  the  operation  greatly  de- 
pends on  the  care  in  the  after  treatment,  par- 
ticularly in  renewing  the  dressing  whenever  it 
has  been  displaced. 

The  anus  is  occasionally  found  much  con- 
tracted in  new-born  children  who  are  con- 
taminated by  syphilis,  and  may  be  mistaken  for 
a  congenital  malformation,  especially  of  the  kind 
last  noticed,  though  not  one  in  the  strict  sense 
of  the  expression;  yet  as  it  generally  occurs 
at  birth,  it  deserves  the  consideration  of  the 
practitioner  in  midwifery,  whose  attention  is 
often  first  called  to  it  by  the  same  symptoms 
that  attend  the  congenital  malformation  of  this 
opening,  namely,  pain,  difficulty,  and  straining 
at  each  evacuation,  and  a  peculiarly  small  aper- 
ture. On  examination,  however,  there  are 

*  See  some  observations  by  Petit,  Mem.  de 
1'Acad.  de  Chirurg.  t.  i.  p.  378. 


other  appe-.ira.nces  which  will  assist  in  explain- 
ing the  real  nature  of  the  case,  such  as  brown 
or  dark  discolouration  of  the  surrounding  parts, 
also  considerable  moisture,  frequently  excoria- 
tion, and  even  superficial  ulceration  in  the  adja- 
cent structures.  Small  fissures  in  the  anus,  also, 
are   observable,  discharging  tenacious  matter. 
Similar  appearances  may  exist  about  the  com- 
missures of  the  lips ;  some  soft  granulations  or 
condylomata  are  also  often  present  in  the  im- 
mediate vicinity  of  the  anus  ;  these  frequently 
extend  into  the  canal  for  a  very  little   way. 
Other  constitutional  symptoms  also  are  usually 
present,  such  as  copper-coloured  blotches  on 
the  skin,  a  tendency  to  cracking  and  excoriation 
of  the  skin  about  the  hands  and  feet,  and  but- 
tocks, an  imperfect  development  of,  or  a  ten- 
dency to  a   separation   of  the   nails,   general 
emaciation,  suspicious  appearances  about  the 
mouth    and    tongue,    and   a  remarkable  and 
peculiar  hoarseness  in  crying.     Many,  if  not 
most  of  these  symptoms,  aided  sometimes  by 
the  history  of  the  parents,  will  lead  the  prac- 
titioner to  distinguish  this  contraction  of  the 
anus  from  the  congenital  malformation  before 
described.     The  distinction  is  important,  as  the 
treatment  in  both  is  totally  different;  the  syphi- 
litic  contraction    invariably    yields   to   gentle 
courses  of  mercury,  administered  in  such  form 
and  dose  as  the  circumstance  of  the  case  shall 
denote  to  be  necessary.     The  local  complaint 
disappears  as  the  constitution   is   restored  to 
health.      Soothing,  emollient  applications  are 
the  best  topical  remedies ;  should  there  be  any 
ulceration  or  excoriation  about  the  part,   the 
surface    should  be   slightly   stimulated   daily, 
either  by  caustic  or  by  the  ordinary  mercurial 
lotions. 

Morbid  conditions. — The  anus  is  the  seat  of 
several  morbid  affections,  some  of  which  pro- 
ceed from  a  specific  cause ;  others  are  merely 
local.  The  specific  diseases  are  syphilis  and 
cancer ;  and  the  most  common  local  derange- 
ments to  which  the  anus  is  subject  are,  super- 
ficial ulcerations,  excoriations,  fissures,  with  or 
without  contraction  of  the  orifice  from  exces- 
sive irritability  of  the  sphincter  muscle,  pro- 
lapsus ani,  haemorrhoids,  fistula  in  ano,  polypi, 
&c.  Some  of  these  last  mentioned  affections 
must,  strictly  speaking,  be  considered  as  ap- 
pertaining to  the  rectum,  under  which  head 
the  reader  will  find  them  noticed.  As,  how- 
ever, the  anus  is  more  or  less  engaged  in  these 
diseases,  we  shall  make  some  observations  on 
each.  The  anus  is  also  subject  to  laceration  in 
parturition,  and  from  other  causes. 

Syphilis  affects  the  anus  at  all  ages  ;  its  ap- 
pearances in  the  infant  have  been  already 
noticed.  In  the  adult  it  may  present  the  primary 
venereal  ulcer,  which  will  have  the  same  cha- 
racter here  as  elsewhere,  only  somewhat  modi- 
fied by  the  position  and  function  of  the  part. 
The  primary  ulcer  may  be  produced  either  by 
the  direct  application  of  the  virus,  or  by  ex- 
tension of  ulceration  from  the  neighbouring 
organs,  as  not  unfrequently  occurs  in  the 
female.  When  the  chancre  is  confined  to  the 
anus,  which  is  very  seldom  the  case,  it  may  be 
difficult  to  discriminate  between  it  and  ulccra- 


184 


ANUS. 


ions  from  other  causes.  Ulcers  in  this  region 
are  very  generally  difficult  and  slow  to  heal, 
owing  to  the  irritation  to  which  they  are  exposed 
from  the  passage  of  the  faeces,  and  from  the 
motion,  pressure,  and  changes  of  form  to  which 
the  parts  are  necessarily  subject.  Syphilis 
frequently  appears  here  in  the  form  of  fissures, 
clefts,  rhagades :  these  are  very  distinct,  and 
different  from  the  fissures  attending  the  irri- 
table anus.  The  syphilitic  fissure  is  chiefly  in 
the  integuments;  it  seldom  extends  to  any 
distance  within  the  anus  :  the  edges  are  some- 
what elevated  and  thickened,  and  the  surface 
secretes  an  adhesive  pus,  which  forms  crusts 
or  scabs.  Although  in  some  instances  these 
fissures  or  rhagades  are  attended  with  pain  in  de- 
faecation,  yet  we  have  met  many  cases  in  which 
they  caused  very  little  uneasiness,  and  thus 
contrasted  remarkably  with  the  simple  or  the 
irritable  fissure.  Warts,  condylomata,  or  ex- 
crescences about  the  anus  are  also  frequent 
effects  of  syphilis  in  this  region.  These  are 
generally  on  the  cutaneous  side  of  the  anus, 
and  very  rarely,  I  believe,  extend  within  it : 
they  are  not,  therefore,  difficult  to  distinguish 
from  those  vascular  excrescences  which  are  of 
mucous  origin,  and  which  so  commonly  pro- 
trude at  the  anus.  Syphilitic  warts  and  con- 
dylomata have  generally  a  broad  base;  their 
surface  is  flattened  by  pressure  against  the  op- 
posite nates,  soft  and  moistened  with  an  offen- 
sive sero-purulent  fluid.  In  these  cases  the 
surrounding  skin  is  often  excoriated,  and  clefts 
and  superficial  ulcers  frequently  exist  in  the 
vicinity  of  the  anus. 

Cancer  is  a  disease  to  which  the  rectum  is 
very  liable,  and  may  attack  any  part  of  the 
intestine,  but  usually  exists  at  some  inches 
above  the  anus.  This  opening,  however,  may 
become  implicated  by  the  extension  of  the  dis- 
ease. We  occasionally  see  that  form  of  cutaneous 
cancer  called  "  cancer  scrott"  extend  along  the 
perinaum  and  involve  the  circumference  of  the 
anus.  Its  parietes  may,  however,  be  prima- 
rily affected  by  cancer,  in  which  case  the 
disease  will  commence  by  a  chap  or  fissure, 
or  more  frequently  by  a  tubercle,  which,  gra- 
dually increasing  in  size  and  in  breadth,  at 
length  ulcerates  and  shoots  out  a  cauliflower 
mass  of  granulations  which  protrude  through  the 
opening,  causing  great  uneasiness,  pain,  and  dif- 
ficulty in  defaecation  :  the  surrounding  parts  in 
time  become  involved,  ulceration  extends,  and 
a  bleeding  surface,  very  unhealthy,  sloughy  in 
some  parts,  and  fungoid  in  others,  discharging 
sanious  and  unhealthy  matter,  is  an  almost  in- 
cessant source  of  pain  and  irritation,  which  in 
time  wastes  the  health  and  strength  of  the 
patient.  As  no  local  application  or  consti- 
tutional treatment  has  yet  been  able  to  arrest 
this  disease,  it  has  been  proposed  to  extirpate 
the  anus  and  the  lower  end  of  the  rectum  when 
in  this  condition.  Unfavourable  as  this  opera- 
tion may  appear,  and  rarely  as  it  has  been 
undertaken  in  this  country,  it  has  been  fre- 
quently performed  in  France,  and  with  some 
success.* 

*  See  Velpeau,  Med.  Oper,  t.  iii.  p.  1033. 


The  anus  is  often  affected  with  warty  ex- 
crescences, which  by  a  superficial  observer  might 
be  condemned  as  cancerous,  yet  these  are  not 
of  a  malignant  character,  and  may  be  cured  by 
local  remedies  and  due  attention  to  the  gene- 
ral health.  I  have  seen  a  warty  tubercular 
appearance  about  the  anus,  extending  through 
it,  and  even  involving  the  mucous  surface  for 
some  height,  and  contracting  the  orifice  so 
much  as  to  cause  great  pain  and  difficulty  in 
defaecation,  and  also  materially  impairing 
the  general  health  by  continual  irritation ;  yet 
this  state  of  parts  is  not  malignant,  nor  is  it 
prone  to  ulceration.  Attention  to  the  consti- 
tution, to  the  functions  of  the  bowels,  with 
local  applications,  will  effect  a  cure.  The  anus 
is  also  frequently  affected,  and  even  incon- 
venienced by  the  growth  of  common  warts  ; 
these,  however,  can  be  speedily  removed  either 
by  the  scissors  or  by  caustic. 

Excrescences  frequently  protrude  through  the 
anal  opening,  which  are  not  warty  or  cutaneous 
growths,  but  elongations  of  the  mucous  mem- 
brane from  a  little  distance  above  the  anus. 
The  anatomical  disposition  of  these  parts,  before 
alluded  to,  together  with  a  very  relaxed  state 
of  the  mucous  membrane,  accounts  for  the  fre- 
quency of  this  occurrence.  In  some  these  pro- 
trusions only  appear  during  defaecation,  in  others 
they  are  permanent,  but  much  increased  in 
volume  during  that  act ;  and,  indeed,  in  some 
they  are  so  large  and  fill  up  so  much  of  the 
canal,  that  they  must  be  extruded  before  the 
faeces  can  escape.  These  excrescences  are  soft, 
and  very  vascular ;  they  often  appear  without 
any  assignable  cause,  though  frequently  they  are 
attributed  to  haemorrhoids,  to  constipation  of 
the  bowels,  to  violent  straining  efforts  in  de- 
faecation, to  fistula,  or  to  long-continued  irrita- 
tion from  any  cause. 

Prolapsus  ani,  or  procidentia  ani,  although 
a  term  in  somewhat  common  use,  is  rather  an 
incorrect  one,  as  the  anus  itself  is  too  well 
maintained  in  its  situation  to  descend,  at  least  to 
any  appreciable  distance;  the  term  rather  implies 
a  protrusion  of  a  considerable  portion  of  the 
relaxed  mucous  membrane  of  the  rectum,  or  a 
portion  of  the  large  intestine  itself,  which  must 
have  become  "  invaginated  or  introsuscepted," 
and  then  protruded  through  the  anus ;  in  these 
conditions  the  anus  is  rather  dilated,  the  mu- 
cous membrane  sometimes  remains  protruded 
after  defaecation,  but  in  others  it  returns  after 
this  process,  or  it  can  be  returned  by  the  gentle 
pressure  of  the  hand :  this  is  not  uncommon 
in  children  and  in  elderly  persons.  This  disease 
has  been  ascribed  to  a  relaxation  of  the  sphincter ; 
a  circumstance  which,  however,  does  not  seem 
to  be  proved,  for  in  paraplegia  and  in  paralysis 
of  the  sphincter,  we  do  not  find  that  the  mem- 
brane protrudes,  although  the  anus  is  often  in 
these  cases  very  dilatable ;  the  condition  referred 
to  ought  perhaps  rather  to  be  considered  as  one 
of  the  effects,  than  as  the  cause  of  the  disease ; 
moreover  in  some  other  instances  the  sphincter 
appears  rather  irritable,  and  painfully  and  dan- 
gerously constricts  the  protruded  mass,  which 
must  then,  in  order  to  save  the  intestine  from 
gangrene,  be  reduced  by  pressure  properly 


ANUS. 


185 


applied,  and  by  attention  to  posture.  In  the 
procidentia  of  old  persons,  Mr.  Hey  conceives 
that  the  relaxed  state  of  the  lower  part  of  the 
intestine  and  of  its  surrounding  cellular  tissue, 
are  in  fault,  and  that  hence  the  folds  or  ex- 
crescences about  the  anus  remain,  even  when 
the  parts  have  been  returned  ;  he  therefore  sug- 
gests the  removal  of  these  flaps  from  the  cir- 
cumference of  the  opening,  and  relates  some 
well-marked  cases  in  support  of  this  practice, 
in  which  the  operation  had  been  successfully 
performed. 

The  margin  of  the  anus,  like  that  of  the 
mouth,  is  subject  to  Ju*ure$t  chaps,  and  super- 
ficial excoriations,  sometimes  caused  by  lace- 
ration induced  by  the  passage  of  large  and 
hardened  faeces,  but  sometimes  arising  spon- 
taneously, and  sometimes  connected  with  a 
peculiarly  irritable  and  contractile  condition  of 
the  sphincter  ani.  This  disease  must  not  be 
confounded  with  haemorrhoids;  on  examin- 
ation it  is  not  easily  seen,  but  little  is  appa- 
rent, the  anus  is  much  contracted,  the  orifice 
somewhat  redder  than  natural,  slightly  tender 
on  pressure,  but  exquisitely  so  on  dilating  it 
by  introducing  the  finger;  this  must  be  done 
cautiously  and  slowly,  a  cleft  will  then  be 
observed  just  where  the  skin  and  mucous 
membrane  join,  generally  on  one  side  extending 
a  little  way,  from  half  an  inch  to  an  inch  and 
a  half,  longitudinally  up  the  intestine;  on  di- 
lating the  part  still  more,  the  surface  of  the 
fissure  will  be  seen  slightly  ulcerated,  and 
when  touched  it  is  exquisitely  painful ;  the 
surrounding  muscle  is  in  a  state  of  rigid  con- 
traction. It  is  doubtful  whether  the  contrac- 
tion is  the  cause  of  the  fissure,  or  whether  the 
latter  is  the  cause  of  the  irritable  and  con- 
tracted condition  of  the  muscle.  Both  expla- 
nations may  be  occasionally  correct;  but  it  is 
most  probable  that  the  irritable  state  of  the 
muscle  induces  the  ulcerated  fissure,  inasmuch 
as  this  muscular  contraction  occasionally  exists 
without  any  fissure,  and  is  then  equally  pain- 
ful ;  and  fissures  frequently  exist,  as  in  syphilis, 
without  inducing  any  spasmodic  constriction 
of  the  muscle,  and  accordingly  are  attended 
with  little  or  no  pain. 

Contraction  of  the  anus  also  frequently  ex- 
ists without  any  fissure ;  sometimes  it  is  con- 
genital, sometimes  it  appears  in  the  adult;  the 
pain  and  other  symptoms  are  nearly  analogous, 
and  as  severe  as  in  the  case  of  fissure ;  the 
examination  by  the  finger  however  does  not 
detect  one  part  to  be  more  painful  than  another, 
as  is  the  case  in  that  disease ;  and  this  is  almost 
the  only  symptom  distinguishing  these  two 
affections. 

The  term  luemorrhoid  has  been  applied  by 
writers,  practitioners,  and  invalids  to  any  con- 
dition of  the  rectum  and  anus  in  which  a 
discharge  of  blood  takes  place.  It  is,  how- 
ever, more  correctly  applied  to  the  small  tu- 
mours which  are  frequently  seen  at  and  very 
close  to  the  inner  border  of  the  anus  or  even 
occupying  the  very  aperture,  also  to  somewhat 
similar  productions  situated  within  the  rectum, 
at  the  distance  of  one,  two,  or  even  three 
inches  above  the  anus.  From  such  tumours 


occupying  these  different  positions,  they  have 
been  arranged  by  all  writers  into  external  and 
internal  haemorrhoids;  the  latter  are  very  im- 
portant and  demand  the  close  attention  of  the 
surgeon,  both  as  to  their  pathology  and  sym- 
ptoms, as  being  frequently  obscure  and  liable 
to  be  mistaken  not  merely  for  the  ordinary 
diseases  of  the  anus,  such  as  fissure,  blind 
internal  fistula,  &cc.,  but  also  to  be  confounded 
with  a  varicose  condition  of  the  veins  of  the 
rectum,  which  is  by  no  means  an  uncommon 
condition,  or  with  those  vascular  tumours 
which  are  productions  of  the  mucous  mem- 
brane occasionally  protruding  at  the  anus, 
that  have  been  already  noticed,  and  are 
of  a  wholly  different  character  from  true  hae- 
morrhoidal  tumours,  or  with  the  protrusions 
of  the  mucous  membrane  itself,  the  effect  of 
the  relaxation  of  its  cellular  connections.  As 
the  full  consideration  of  this  important  branch 
of  pathology  belongs  to  the  article  on  the  mor- 
bid anatomy  of  the  rectum,  we  shall  here  con- 
fine ourselves  to  a  few  observations  on  external 
haemorrhoids  and  analogous  tumours. 

External  hemorrhoids  appear  at  the  border 
of  the  anus  as  small  bluish  tumours,  the 
colour  however  varying  according  to  the  con- 
dition of  the  tumours,  being  sometimes  of  a 
dark  and  deep  red  or  black,  at  others  pale  and 
almost  white ;  in  size  they  vary  from  a  grain 
of  small  shot  to  a  large  cherry ;  they  are  some- 
times full  and  almost  bursting,  at  others  they 
are  soft  like  a  flaccid  nipple,  empty  or  with- 
ered ;  they  are  covered  on  the  anal  side  by  the 
delicate  cuticle  which  is  smooth  and  glossy, 
and  on  the  outer  side  by  the  common  integu- 
ment; when  small,  they  are  moveable  and  can 
be  distinctly  felt  to  be  in  the  subcutaneous 
cellular  tissue;  when  large  and  tense,  they  ap- 
pear more  connected  with  the  skin  itself; 
an  attentive  examination  can  always  distinguish 
between  these  and  the  several  excrescences, 
vegetations,  or  condylomata,  which  have  been 
already  mentioned  as  the  effects  of  syphilis, 
as  also  the  folds  or  crests  of  integument  and 
mucous  membrane  which  are  found  so  fre- 
quently prolonged  from  the  border  of  the 
anus.  These  tumours  remain  in  many  persons 
for  years  free  from  pain,  and  productive  of 
little,  if  of  any,  inconvenience ;  occasionally, 
however,  and  periodically  in  some,  they  en- 
large, inflame,  and  interfere  with  the  functions 
of  the  anus,  and  by  sympathy  engage  the  ad- 
jacent organs,  and  are  relieved  either  by  a 
copious  discharge  of  blood,  or  by  suppuration, 
or  by  the  interference  of  art. 

The  liability  of  the  veins  immediately  about 
the  anus  to  varicose  enlargement  appears  in 
some  measure  founded  in  anatomical  structure. 
If  we  inject  the  intestinal  veins  in  the  adult 
with  wax  injection,  we  shall  often  find  a  little 
above  the  anus,  just  where  the  skin  and  mu- 
cous membrane  unite,  a  sort  of  constriction  on 
the  vessels;  the  veins  appear  larger  imme- 
diately above  it,  and  again  below  it,  and 
many  of  the  branches  in  the  venous  plexus 
around  the  anus  appear  to  be  enlarged,  while 
in  the  very  spot  or  circular  line  alluded  to, 
the  vessels  appear  to  be  compressed.  It  may 


186 


ANUS. 


occur,  then,  that  hardened  faeces  impacted  in 
the  rectal  pouch,  which  is  above  this  point,  may 
assist  in  obstructing  the  more  free  flow  of 
blood,  and  thus  encourage  the  enlargement 
of  these  anal  veins,  and  the  same  effect  may 
be  still  further  induced  by  the  muscular  pres- 
sure employed  in  defaecation ;  in  support  of 
this  view  we  find  that  children  are  almost  free 
from,  this  varicose  condition  of  these  veins, 
unless  under  peculiar  circumstances ;  and  in 
the  adult  it  usually  occurs  in  those  of  con- 
stipated habit  of  bowels ;  it  is  also  relieved  or 
removed  by  attention  to  their  functions.  The 
true  hsemorrhoidal  tumours,  external  as  well  as 
internal,  must  be  rega'rded  as  essentially  dif- 
ferent from  a  varicose  condition  of  the  anal 
veins,  although  they  are  often  connected  with 
the  latter,  and  it  must  be  admitted  that  in 
some  cases  they  may  owe  their  origin  in  a  great 
-measure  to  venous  dilatation.  Varices  of  the 
anal  veins  are  simple  dilatations  either  of  a 
trunk  or  of  some  of  the  branches  of  these 
vessels ;  their  cavity  is  continuous  with  that  of 
the  vein,  and  freely  communicates  with  it, 
and  pressure  on  the  varix  empties  it  of  its 
contents ;  its  tunics  are  the  venous  coats  and 
the  membrane  of  the  intestine;  whereas  hremor- 
rhoidal  tumours  are  wholly  distinct  from  the 
veins,  and  are  either  simple  cysts,  lined  by 
a  smooth  membrane,  or  they  are  composed 
of  a  spongy  cellular  texture,  not  unlike  the 
erectile  tissue.  This  latter  is  usually  the  con- 
dition of  recently  formed  haemorrhoids,  whereas 
in  those  of  long  standing  the  single  or  divided 
cyst  is  the  ordinary  structure ;  this  cyst  will  be 
found  to  contain  a  little  blood,  partly  fluid 
and  partly  coagulated  ;  and  when  the  internal 
surface  is  minutely  examined,  one  or  more 
fine  pores  will  be  visible,  the  orifices  of  ca- 
pillary vessels,  through  which  warm  water, 
if  steadily  injected  by  the  inferior  mesenteric 
artery,  will  exude  on  the  surface.  In  the  cellular 
or  more  recent  haemorrhoids  the  texture  ap- 
pears very  vascular,  soft,  and  spongy,  as  also 
the  surface  of  the  tumour,  from  which  blood  or 
serum  will  sometimes  exude  during  life. 
These  cellular  haemorrhoids  in  time  become 
circumscribed,  the  cellular  texture  becomes 
more  or  less  perfectly  absorbed,  and  the  cyst- 
like  structure  becomes  more  developed  ;  how- 
ever a  very  recently  formed  haemorrhoid  may, 
and  sometimes  does,  present  a  distinct  cyst  or 
cavity,  as  may  be  readily  conceived  when  we 
consider  the  process  whereby  these  tumours 
come  to  be  developed,  which,  as  far  as  our 
observation  extends,  is  as  follows :  from  con- 
tinued irritation  from  any  exciting  cause,  such 
as  disease  of  the  intestine  or  anus,  worms,  or 
from  a  local  plethoric  condition,  spontaneous, 
as  far  as  we  can  know,  the  capillary  circulation 
is  increased  in  the  loose  submucous  tissue  in 
this  region,  a  small  quantity  of  blood,  or 
lymph,  or  serum,  is  effused  into  it,  perhaps 
from  the  rupture  of  some  small  vessels,  or 
exhaled  from  their  dilated  extremities.  A 
slight  degree  of  inflammation  attends  this  con- 
dition :  the  part  affected,  that  is,  the  cellular 
tissue,  becomes  more  highly  organized,  thick- 
ened, vascular,  and  spongy.  After  some  time, 


this  increased  vascular  action  subsides,  and  in 
process  of  time  the  whole  may  nearly  dis- 
appear, but  in  general  a  part  of  this  more 
highly  organized  spongy  tissue  remains,  it 
being  fully  supplied  with  nourishment;  the 
absorbents  in  due  course  modify  its  appear- 
ance ;  the  surrounding  thickening  is  removed, 
as  also  some  portion  of  the  cellular  mass, 
and  thus  the  formation  of  the  haemorrhoidal 
cyst  is  completed.  A  structure  like  this,  con- 
nected with  the  capillary  system,  must  be 
influenced  by  the  same  causes  as  can  affect 
the  latter  ;  thus  irritation  local  or  general,  me- 
chanical injury,  or  general  or  local  plethora 
are  all  capable  of  exciting  increased  action  in  it, 
and  of  inducing  all  those  symptoms  and  changes 
which  are  so  well  known  to  attend  during 
haemorrhoidal  inflammation. 

Fistula  in  ano  is  a  disease  of  such  very  fre- 
quent occurrence,  and  so  well  understood  and 
described  by  every  surgical  writer,  that  it  is 
scarcely  necessary  to  do  more  than  allude  to 
it  in  this  place :  strictly  speaking  it  is  not  a 
disease  of  the  anus,  as  that  opening  is  in 
general  totally  unaffected,  except  as  regards  its 
functions :  it  should  rather  be  regarded  as  a 
disease  of  the  anal  region.  There  is  one  form 
of  fistula  in  ano,  however,  which  is  seated  on 
the  very  confines  of  this  opening ;  it  is  trou- 
blesome and  distressing,  attended  with  heat, 
itching,  and  excoriation,  pain  during  defaeca- 
tion, and  constant  purulent  or  sero-purulent 
discharge :  without  due  attention  it  may  be 
overlooked  by  the  surgeon,  as  the  orifice  is  so 
close  to  the  anus  as  to  be  concealed  by  the 
natural  rugae,  and  so  small  as  only  to  admit  a 
lachrymal  probe ;  the  sinus  is  not  more  than 
an  inch  or  half  an  inch  long;  its  internal 
opening  is  on  the  very  edge  of  the  anus,  the 
whole  is  immediately  under  the  skin,  and  does 
not  involve  any  other  structure ;  it  is  not  pre- 
ceded by  regular  abscess,  neither  does  it  or  the 
treatment  necessary  for  its  cure  involve  the 
sphincter  or  any  other  structure,  except  the 
fine  integuments ;  it  most  probably  originates 
in  irritation  of  some  of  the  anal  sebaceous 
follicles,  and  sometimes  two  or  three  of  such 
fistulae  may  exist  at  the  same  time. 

The  true  or  deep  fistula  in  ano  has  its  origin 
in  deep-seated  abscess  commencing  close  to 
the  rectum,  or  in  the  centre  of  the  ischio-rectal 
space  of  either  side :  when  in  the  former, 
some  mechanical  irritant  or  some  disease  of 
the  intestine  may  have  been  the  cause  or 
origin  of  the  abscess ;  when  in  the  latter,  it 
often  arises  without  any  obvious  reason,  but 
frequently  appears  to  have  been  connected 
with  some  peculiar  delicate  or  morbid  con- 
dition of  the  constitution.  All  abscesses  in 
this  situation  do  not  necessarily  end  in  fistula ; 
if  they  have  been  small,  superficial,  opened 
early,  and  treated  judiciously,  they  may  be 
healed  as  perfectly  as  abscesses  in  any  other 
situation;  but  when  deap-seated,  of  slow 
growth,  and  long  continuance,  and  when  de- 
pending on  some  deep-seated  mechanical  irri- 
tant or  on  constitutional  causes,  then  the  ab- 
scess usually  attains  considerable  size,  and 
having  opened  either  into  the  rectum  or  through 


AORTA. 


187 


the  integuments,  or  in  both  these  directions, 
it  continues  to  secrete  and  to  discharge  a  con- 
siderable quantity,  and  shews  no  disposition  to 
alter  its  action  or  to  heal.  We  have  already 
detailed  all  the  local  peculiarities  of  the  ischio- 
rectal  region  (the  seat  of  this  abscess)  which 
can  satisfactorily  explain  the  difficulty  or  the 
impossibility  of  keeping  at  rest  or  retaining  in 
apposition  the  sides  of  the  cavity,  a  condition 
almost  essential  to  the  healing  of  an  abscess  in 
any  situation,  and  hence  the  necessity  of  sur- 
gical interference.  Abscess  in  this  region 
frequently  originates  close  to  the  rectum  in 
consequence  of  irritation  and  ulceration  in  this 
intestine;  this  irritation  may  be  caused  by 
disease,  such  as  cancer  or  stricture  of  the 
rectum,  or  by  some  foreign  body  becoming 
impacted  in  one  of  the  lacunae.  Above  the 
sphincter  is  the  rectal  pouch,  and  an  irre- 
gularly shaped  or  sharp  substance,  such  as  a 
pin,  a  fish-bone,  or  one  of  the  small  bones  of 
a  fowl,  &c.  brought  into  this  in  the  fcecal  mass, 
may  catch  in  its  villous  or  rugous  surface,  the 
muscular  powers  of  the  intestine  are  excited 
by  this  irritation  to  increased  and  repeated 
efforts  of  expulsion ;  these  only  serve  to  im- 
pact more  closely  the  foreign  body  in  the 
parietes  of  the  intestine ;  the  submucous  tissue, 
which  may  now  contain  the  whole  or  part  of 
this  substance,  becomes  inflamed,  suppuration 
follows,  an  abscess  is  formed  close  to  the  intes- 
tine; in  some  time  the  matter  is  discharged 
either  through  the  rectum  and  anus,  or  coming 
to  the  surface  of  the  nates  it  receives  exit  by 
puncture.  In  this  case  of  abscess,  which  we 
suppose  to  have  been  caused  by  a  foreign  body 
impacted  in  the  intestine,  the  matter  is  usu- 
ally discharged  by  the  rectum,  at  least  at  first, 
although  this  exit  will  not  always  prevent  it 
still  tending  towards  the  cutaneous  surface  : 
in  cases  of  fistula,  however,  arising  from  such 
a  cause,  we  are  most  likely  to  meet  with  the 
blind  internal  jistula,  at  least  in  the  early 
period;  whereas,  when  abscess  forms  spon- 
taneously in  this  region,  and  opens  on  the 
surface,  the  intestine  is  often  at  first  and  for 
some  time  wholly  disengaged  from  the  disease, 
even  after  the  abscess  has  opened,  notwith- 
standing which  it  is  productive  of  great  in- 
convenience and  more  or  less  of  pain  during 
defaecation ;  in  this  state,  when  the  fistula  or 
abscess  remains  discharging  through  the  skin 
only,  it  constitutes  what  is  termed  a  blind 
external  jistula ;  by  degrees  the  rectum  be- 
comes denuded,  and  ultimately  ulceration 
opens  it  by  one,  and  sometimes,  but  rarely, 
by  more  orifices ;  this  opening  is  usually  about 
half  an  inch  above  the  edge  of  the  anus,  and 
between  the  two  sphincters.  I  have  observed 
it  to  hold  this  situation  in  a  great  number  of 
cases,  which  I  have  examined  both  in  the 
living  and  the  dead ;  in  a  few  instances,  how- 
ever, I  have  found  it  opening  at  a  higher  point. 
When  the  abscess  arises  from  irritation  in  the 
rectum,  then  I  have  observed  the  internal 
opening  to  be  higher,  that  is,  in  the  dilated 
pouch  of  the  rectum,  which  during  life  will 
appear  to  be  from  an  inch  and  a  half  to  two 
inches  from  the  anus ;  but  when  the  abscess 


has  commenced  spontaneously  in  the  anal 
adeps,  and  opened  on  the  surface  first,  I  have 
then  in  general  found  the  rectal  opening  less 
than  an  inch  distant  from  the  anal  orifice,  and 
in  a  groove  or  recess  between  the  two  sphinc- 
ters. When  the  abscess  discharges  by  two 
openings,  that  is,  through  the  skin  and  through 
the  rectum,  a  perfect  or  complete  jistula  is  then 
said  to  exist. 

Fistulas  occasionally  appear  in  the  anal  region 
which  have  their  source  at  a  much  greater  dis- 
tance; thus,  any  diseases  of  the  uterus  or 
vagina  in  the  female,  of  the  prostate  or  urethra 
in  the  male,  which  end  in  suppuration,  may 
cause  collections  of  pus  which  will  burrow 
under  the  fasciae  and  skin  to  the  vicinity  of 
the  anus,  and  open  near  it  or  even  into  the 
rectum.  Psoas  and  lumbar  abscesses  also  may 
descend  into  the  pelvis  and  approach  the  sur- 
face, either  in  front  or  at  one  side  of  the  anus. 
In  morbus  coxae  also  chronic  abscesses  which 
form  about  the  nates  not  unfrequently  open  in 
the  same  situation. 

Polypus  is  seldom  a  disease  of  the  anus ;  it 
most  usually  grows  from  the  rectum,  and  pro- 
trudes occasionally  only  at  the  anus. 

(Robert  Harrison.) 

For  the  Bibliography  of  this  article  see  that 
of  INTESTINAL  CANAL. 

AORTA*  (human  anatomy).  —  (Arteria 
magnet.  Fr.  aorte.  Germ.  Aorta,  die  grouse 
Schlagader.  Gr.  «O^T«.)  Hippocrates  applied 
the  term  ao^ra*  to  the  lower  part  of  the  bronchi. 
Aristotle  called  the  great  trunk  of  the  arterial 
system  <pfa^  otogrri. 

The  aorta,  one  of  the  two  great  arteries 
which  spring  from  the  heart,  is  the  trunk  of  the 
arterial  system  of  the  general  circulation ;  it 
arises  from  the  extreme  right  part  of  the  base 
of  the  left  ventricle  of  the  heart,  which,  from 
this  circumstance,  is  sometimes  called  the 
aortic  ventricle.  There  is  a  ring  of  tendinous 
structure  surrounding  the  aortic  opening  of  the 
ventricle,  which  in  the  stag  and  some  others  of 
the  ruminantia  is  more  or  less  partially  ossified; 
into  this  ring  the  muscular  fibres  of  the  heart 
are  inserted.  The  middle  tunic  of  the  aorta 
is  divided  at  its  commencement  into  three 
semicircular  flaps  by  an  equal  number  of  angu- 
lar notches,  forming  thus  a  festooned  edge 
which  is  bordered  throughout  its  whole  extent 
by  a  marginal  tendinous  cord.  These  three 
semicircular  flaps  touch  the  aortic  opening  of 

*  The  etymology  of  this  term  is  by  no  means 
clear.  The  following  extract  from  Spigelius  (de 
corp.  hum.  fabrica)  gives  a  not  improbable  origin 
for  it.—  "Veteribus  Graecis  aoprnv  dictam  fuisse 
vaginam  cultrorum  Macedonibus  familiarem,  quo- 
rum manubrium  nonnihil  incurvatum  erat,  ad  quam 
sane  figuram  quam  proxime  accedere  videtur  arte- 
riae  magnae  truncus,  qua  parte  ex  corde  onginem 
suam  d ucit."  Cloquet  suggests  the  theme,  etof  reopen, 
suspendor,  "  parceque  I'aorte  consideree  dans  sa. 
totalite  parait  comme  suspendue  an  cceur."  Aris- 
totle, by  whom  the  term  seems  to  have  been  first 
employed,  generally  denominated  it  4>Xs4-  t'ha.rrw, 
in  reference  to  the  vena  cava,  which  he  considered 
the  greater  vein. —  R.  B.  T. 


188 


AORTA. 


the  ventricle  at  three  equidistant  points  by  the 
centres  of  their  convex  edges,  where  the  fibres 
of  their  marginal  cord  become  intimately 
blended  with  those  of  the  tendinous  ring  of  the 
aortic  opening  of  the  ventricle ;  between  these 
points  are  three  triangular  intervals,  each  of 
which  is  occupied  by  a  thin  tendinous  expansion 
of  considerable  strength,  having  one  of  its  sides 
continuous  with  the  tendon  which  encircles 
the  aortic  opening  of  the  ventricle,  and  the 
other  two  continuous  with  the  marginal  ten- 
dinous cord  of  the  festooned  commencement 
of  the  middle  tunic  of  the  aorta. 

The  convex  margins  of  the  sigmoid  valves  of 
the  aorta  are  attached  to  the  margins  of  the 
semilunar  flaps,  and  are  composed  of  thin  ex- 
pansions sent  off  from  their  marginal  tendinous 
cord,  covered  by  a  reflexion  of  the  lining  mem- 
brane common  to  the  heart  and  arteries.  Hence 
it  follows  that  the  fibres  of  the  middle  tunic 
of  the  aorta  are  not  continuous  with  the 
muscular  fibres  of  the  ventricle,  being  sepa- 
rated from  them  by  the  tendinous  structure 
above  described  ;  this  tendinous  connexion  is 
strengthened  and  supported  externally  by  a 
layer  of  dense  cellular  membrane,  which  may 
be  regarded  as  the  commencement  of  the 
cellular  or  external  tunic  of  the  arterial 
system.  The  lining  membrane  of  the  heart, 
after  being  reflected  over  the  sigmoid  valves, 
extends  itself  into  the  aorta,  and  becomes 
continuous  with  the  lining  membrane  of  that 
vessel.  The  muscular  substance  of  the  heart 
rises  in  form  of  a  swollen  annular  border 
around  the  commencement  of  the  aorta  for  a 
little  distance,  and  is  connected  to  it  by  dense 
cellular  membrane.  The  serous  layer  of  the 
pericardium  passes  loosely  from  the  surface 
of  the  heart  over  the  aorta;  a  quantity  of 
soft  adipose  substance,  which  is  absent  in  the 
foetus  during  the  earlier  months,  begins  to 
collect  under  the  serous  membrane  in  this 
situation,  sometimes  before,  sometimes  after 
birth,  and,  increasing  as  life  advances,  is  found 
in  considerable  quantity  in  old  age.  The  fore- 
going description  of  the  connexion  of  the  aorta 
with  the  heart  has  been  determined  by  my  own 
dissections  repeatedly  performed,  and  agrees,  in 
its  leading  particulars,  with  the  account  given 
of  it  by  M.  Beclard* 

The  aorta,  arising  from  the  left  ventricle 
of  the  heart  opposite  the  left  side  of  the  body 
of  the  fourth  thoracic  vertebra,  ascends  at  first 
obliquely  forwards,  and  to  the  right  behind  the 
middle  bone  of  the  sternum,  until  it  arrives 
at  the  right  side  opposite  the  second  intercostal 
space,  and  behind  the  sternal  articulation  of 
the  cartilage  of  the  second  rib ;  it  then  stretches 
backwards  and  to  the  left,  opposite  the  junction 
of  the  upper  and  middle  portions  of  the  ster- 
num, on  a  level  with  the  body  of  the  second 
thoracic  vertebra,  and  curving  downwards  it 
reaches  the  left  side  of  the  body  of  the  third 
thoracic  vertebra,  on  which  there  is  a  slight 
depression  for  lodging  it;  from  this  point  it 
descends  through  the  posterior  mediastinum, 

*  Diet,  de  Medecine,  art.  Aorte.  Elemens 
d'Anat.  Generate,  par  Beclard.  Paris,  1823. 


advancing  in  its  course  downwards  from  the 
left  side  to  the  front  of  the  bodies  of  the  ver- 
tebrae ;  it  passes  through  the  aortic  opening  of 
the  diaphragm,  enters  the  abdomen,  and  on  the 
body  of  the  fourth  abdominal  vertebra  gives 
off  the  two  primitive  iliac  arteries,  in  which  it 
seems  at  first  view  to  terminate;  the  aorta, 
however,  does  not  end  here,  but  is  continued, 
although  greatly  reduced  in  size,  under  the 
name  of  the  middle  sacral  artery,  as  far  as 
the  extremity  of  the  os  coccygis. 

The  aorta  is  usually  divided  by  anatomists 
into  three  portions;  the  curved  portion  fiom 
the  heart  to  the  third  thoracic  vertebra  is  called 
the  Arch  of  the  aorta  ;  the  remaining  portion 
of  the  vessel,  to  which  the  name  of  descending 
aorta  has  been  sometimes  given,  is  called 
Thoracic  aorta  above  the  diaphragm,  and  Ab- 
dominal  aorta  below  that  muscle. 

The  Arch  of  the  aorta  is  divided  into  three 
portions,  for  the  purpose  of  describing  its  nu- 
merous important  relations  to  surrounding  parts 
with  greater  accuracy;  these  are,  first,  the 
ascending  or  anterior  limb  ;  second,  the  trans- 
verse portion  ;  and,  thirdly,  the  descending  or 
posterior  limb.  The  commencement  of  the 
aorta  is  covered  anteriorly  and  to  the  left  by 
the  pulmonary  artery,  on  the  right  by  the  right 
auricular  appendage,  the  tip  of  which  overlaps 
it  in  front,  and  behind  it  rests  on  the  sinus 
of  the  left  auricle.  The  ascending  limb  of  the 
arch  lies  first  in  front  of  the  right  pulmonary 
artery,  as  that  vessel  crosses  behind  it  in  its 
course  to  the  right  lung,  and  then  it  gets  in  front 
of  the  right  bronchus,  and  the  cluster  of  bron- 
chial glands  which  fill  up  the  angle  formed  by 
the  bifurcation  of  the  trachea;  it  is  bounded 
on  the  right  side  by  the  superior  vena  cava, 
and  on  the  left  by  the  pulmonary  artery ;  an- 
teriorly it  is  separated  from  the  sternum  by  the 
anterior  margins  of  both  lungs,  which  here 
approximate,  and  by  the  narrowest  part  of  the 
anterior  mediastinum,  where  the  attached  sur- 
faces of  the  opposite  pleurae  touch.  This 
portion  of  the  aorta  is  contained  within  the  bag 
of  the  pericardium,  the  serous  layer  of  which 
invests  it  in  every  part  except  where  it  lies 
in  contact  with  the  pulmonary  artery. 

The  transverse  portion  of  the  arch  is  shorter 
than  the  ascending  limb.  The  three  great  arte- 
ries of  the  head  and  upper  extremities  arise 
from  its  superior  sides ;  inferiorly  it  rests  on  the 
left  bronchial  tube  ;  in  front  it  has  the  cellular 
membrane  of  the  anterior  mediastinum,  the 
thymus  gland,  and  the  inferior  part  of  the  vena 
innominata;  behind  it  rests  on  the  trachea  a 
little  above  its  bifurcation,  and  on  the  left  re- 
current nerve.  The  posterior  limb  is  the  shortest 
portion  of  the  arch;  it  lies  immediately  behind 
the  division  of  the  pulmonary  artery,  which 
is  connected  to  it  by  a  ligament,  the  remains  of 
the  ductus  arteriosus ;  and  it  is  crossed  by  the 
left  par  vagum ;  on  the  right  side  it  is  in  con- 
tact with  the  oesophagus,  thoracic  duct,  and 
left  side  of  the  body  of  the  third  thoracic  ver- 
tebra ;  the  rest  of  the  circumference  of  the 
thoracic  aorta  is  covered  by  the  left  pleura,  and 
is  in  contact  with  the  internal  surface  of  the 
left  lung.  In  the  generality  of  adults  having 


AORTA. 


189 


the  chest  well  formed,  and  the  heart  and  the 
arch  of  the  aorta  free  from  disease,  the  origin 
of  the  aorta  is  opposite  the  sternal  articulation 
of  the  cartilage  of  the  fourth  rib  of  the  left 
side  in  the  male,  and  the  intercostal  space 
above  it  in  the  female;  the  ascending  limb  of 
the  arch,  which  is  behind  the  middle  bone 
of  the  sternum  in  the  greater  part  of  its  length, 
may  be  felt  pulsating  on  the  right  side  of  the 
sternum  in  the  second  intercostal  space ;  the 
highest  part  of  the  transverse  portion  of  the 
arch  is  on  a  plane  with  the  centre  of  the  sternal 
extremities  of  the  first  pair  of  ribs,  and  about 
an  inch  below  the  upper  margin  of  the  ster- 
num :  the  arch  of  the  aorta  terminates  oppo- 
site the  lower  edge  of  the  cartilage  of  the 
second  rib  of  the  left  side. 

The  t/wracic  aorta  descends  in  the  posterior 
mediastinum,  and  advances  from  the  left  side 
to  the  front  of  the  thoracic  portion  of  the  spine, 
crossing  in  its  course  the  left  intercostal  veins, 
and  the  left  vena  azygos  when  that  vein  exists ;  in 
front  it  is  covered  by  the  left  bronchus,  the  pos- 
terior surface  of  the  pericardium,  the  lower  ex- 
tremity of  the  oesophagus,  and  the  left  stomachic 
cord  of  the  par  vagum  ;  on  the  right  side  it  is 
bounded  by  the  oesophagus,  thoracic  duct,  and 
vena  azygos ;  on  the  left  side  it  is  covered  by 
the  pleura,  and  in  contact  with  the  internal 
surface  of  the  left  lung,  and  at  its  lower  extremity 
the  left  splanchnic  nerve  comes  into  contact 
with  it,  and  most  frequently  accompanies  it 
through  the  diaphragm. 

The  abdominal  aorta,  which  enters  the  abdo- 
men between  the  crura  of  the  diaphragm,  des- 
cends along  the  front  of  the  abdominal  ver- 
tebrae and  the  left  lumbar  veins;  it  is  covered 
in  front  by  the  solar  plexus  of  nerves,  the 
stomach,  pancreas,  transverse  portion  of  the 
duodenum,  the  splenic  and  left  renal  veins,  the 
small  intestine,  and  the  root  of  the  mesentery  ; 
on  the  right  side  it  is  bounded  by  the  abdomi- 
nal vena  cava,  and  the  commencement  of  the 
thoracic  duct,  and  on  the  left  it  is  covered  by 
the  peritoneum  going  to  form  the  left  layer 
of  the  mesentery.  The  termination  of  the  aorta 
in  the  common  iliacs  and  the  middle  sacral 
arteries  is  a  little  below  the  level  of  the  um- 
bilicus. 

A  remarkable  deviation  from  the  cylindrical 
form,  which  is  one  of  the  general  characteristics 
of  the  arterial  system,  is  observable  in  two  parts 
of  the  arch  of  the  aorta ;  the  first  of  these  occurs  at 
the  commencement  of  this  vessel  in  form  of  three 
dilatations  corresponding  to  the  semilunar  flaps 
already  described  ;  they  were  first  pointed  out 
by  Valsalva,  and  have  received  the  name  of  the 
lesser  sinuses  of  the  aorta ;  they  exist  at  all 
periods  of  life,  and  increase  in  size  with  years ; 
the  other  deviation  from  the  cylindrical  form  is 
a  dilatation  on  the  right  side  of  the  ascending 
limb  of  the  arch  at  its  junction  with  the  trans- 
verse portion  ;  this  dilatation,  which  does  not 
exist  in  the  foetus,  grows  larger  as  life  advances, 
and  appears  to  be  produced  by  the  impulse 
of  the  blood  striking  against  this  part  of  the 
aorta  at  each  successive  systole  of  the  left 
ventricle.  The  aorta  in  the  succeeding  part  of 
its  course  gradually  grows  smaller  in  a  degree 


proportionate  to  the  size   of  the   branches  it 
gives  off. 

The  thickness  of  the  aorta  is  proportionally 
less  than  that  of  its  branches;  it  is  thinner  at  its 
commencement  than  in  the  arch,  in  which  part, 
according  to  Haller,  it  is  thicker  by  an  eighth 
on  the  convex  than  on  the  concave  side;  it 
gradually  diminishes  in  thickness  as  it  descends 
through  the  thorax  and  abdomen,  but  its  power 
of  resisting  distention  instead  of  being  dimi- 
nished in  an  equal  degree  was  found  by  Win- 
tringham  to  be  greater  at  its  lower  part  than 
near  the  heart.* 

The  structure  of  the  aorta  is  the  same  as 
that  of  the  rest  of  the  arterial  system  in  general ; 
its  external  tunic,  however,  is  slighter  than  that 
of  all  other  arteries  except  those  of  the  brain, 
it  is  weaker  the  nearer  it  is  examined  to  the 
origin  of  the  aorta  ;  it  is  strengthened  near  the 
heart  by  the  covering  which  the  serous  layer  of 
the  pericardium  gives  to  the  aorta,  and  by  an 
expansion  from  the  fibrous  layer  of  that  mem- 
brane, which  is  lost  on  the  transverse  portion  of 
the  arch.  The  cellular  sheath  of  the  aorta  in 
which  the  soft  fat  around  its  origin  is  deposited, 
becomes  so  fine  where  the  vessel  is  passing  out 
of  the  pericardium  as  to  lead  some  anatomists 
to  deny  its  existence  in  this  situation ;  it  becomes 
more  evident  in  the  course  of  the  descending 
aorta  through  the  mediastinum,  and  is  still 
more  considerable  around  the  abdominal  aorta, 
where  it  is  usually  loaded  with  a  considerable 
quantity  of  adipose  substance. 

The  branches  which  arise  immediately  from 
the  aorta  may  be  divided  into  orders,  according 
to  the  degree  of  remoteness  or  the  relative  size 
and  importance  of  the  parts  which  they  supply 
with  blood ;  first,  the  branches  which  convey 
blood  to  the  two  extremities  of  the  trunk  and 
the  limbs  attached  to  them ;  these  arteries, 
which  are  of  considerable  size,  are  the  arteria 
innominata,  the  leftc  arotid  and  left  subclavian, 
which,  arising  from  the  transverse  portion  of 
the  arch,  are  distributed  to  the  head,  neck,  and 
upper  extremities,  and  the  primitive  ili&c  arte- 
ries which  arise  from  the  lower  part  of  the 
abdominal  aorta  supplying  the  pelvis  and  the 
lower  extremities.  2nd  order. — Branches  some- 
what smaller  going  to  the  thoracic  and  abdomi- 
nal viscera  and  the  parietes  of  the  chest  and 
abdomen ;  the  coronary  arteries  which  supply 
the  heart  arise  from  the  aorta  immediately  after 
its  origin ;  the  bronchial  arteries  which  supply 
the  substance  of  the  lungs,  and  the  intercostal 
arteries  supplying  the  parietes  of  the  chest 
arise  from  the  thoracic  aorta;  the  cceliac,  su- 
perior and  inferior  mesenteric,  which  supply 
the  digestive  organs ;  the  renal  arteries  which 
supply  the  kidnies ;  the  spermatic  going  to  the 
organs  of  generation,  the  inferior  phrenic  sup- 
plying the  diaphragm,  and  the  lumbar  arteries 
going  to  the  parietes  of  the  abdomen  and  lum- 
bar region  of  the  spine,  are  the  vessels  of  this 
order  which  arise  from  the  abdominal  portion 
of  the  aorta.  3rd  order. — Branches  of  much 
smaller  size  are  sent  from  the  aorta  to  se- 

*  Experimental  Inquiry  on  some  parts  of  the 
Animal  Structure.  London,  1740. 


190 


AORTA. 


condary  parts  which  lie  in  its  vicinity,  as  the 
thymus,  the  pericardium,  the  oesophagus,  the 
lenal  capsules,  ureters,  &c.  4th  order. — Small 
arterial  twigs  lost  in  the  neighbouring  cellular 
substance,  lymphatic  glands,  and  in  the  coats 
of  the  aorta  itself. 

Development.  —  The  aorta  appears  to  be 
formed  in  the  foetus  prior  to  the  heart  and  sub- 
sequently to  the  system  of  the  vena  porta,  with 
which,  according  to  Baer,  Rathke,  and  Meckel, , 
it  is  connected  by  a  small  dilatation  described  by 
Dr.  Allen  Thomson*  as  a  curved  tube,  which  is 
the  rudiment  of  the  heart.  (See  OVUM.)  Whilst 
the  heart  has  but  a  single  ventricle,  the  aorta  and 
the  pulmonary  artery  form  a  common  trunk, 
which  afterwards  becomes  divided  by  the  de- 
delopment  of  the  contiguous  portions  of  the 
circumference  of  both  vessels  ;  during  the 
remaining  periods  of  intra-uterine  life,  and 
for  a  short  time  after  birth,  the  pulmonary 
artery  communicates  with  the  aorta  by  the  duc- 
tus  arteriosus,  which  appears  as  a  continuation 
of  the  trunk  of  the  pulmonaiy  artery  opening 
into  the  concavity  of  the  arch  of  the  aorta  at  its 
termination.  The  ductus  arteriosus  becomes 
impervious  soon  after  birth,  and  having  under- 
gone a  process  of  complete  obliteration,  is  finally 
concerted  into  a  ligamentous  cord.  The  size 
of  the  arch  of  the  aorta  is  less  in  proportion  in 
the  foetus  than  in  the  adult,  whilst  the  thoracic 
aorta  is  larger,  being  increased  in  size  below 
the  ductus  arteriosus.  The  arch  lies  closer  to 
the  spine  in  the  foetus  in  consequence  of  the  tra- 
chea and  bronchi  behind  it  being  so  much  less 
developed  than  in  the  adult,  and  the  thymus 
which  is  between  it  and  the  sternum  being 
so  much  larger  during  foetal  life.  In  old  age 
the  curvature  of  the  arch  of  the  aorta  is  much 
greater  in  consequence  of  the  great  sinus  having 
increased  considerably  in  size. 

Anomalies. — The  aorta  presents  occasional 
varieties  or  anomalies  in  the  mode  of  its  origin, 
its  course,  termination,  and  the  number  and 
situation  of  its  branches.  It  is  an  interesting 
fact,  that  almost  every  irregularity  hitherto 
observed  in  the  course  and  branching  of  the 
aorta  in  the  human  subject,  represents  the  dis- 
position which  that  vessel  constantly  exhibits 
in  some  of  the  inferior  animals.  The  anomaly 
pf  the  aorta  arising  from  both  ventricles,  and 
causing  that  condition  called  cyanosis,  will  be 
more  properly  considered  in  the  article  HEART, 
The  following  anomalies  of  the  course  of  the 
aorta  have  been  recorded  by  anatomists  : — 

1st.  The  aorta  sometimes  divides  imme- 
diately after  its  origin  into  a  right  and  left 
trunk,  which,  after  having  each  given  off  the 
arteries  of  one  side  of  the  head  and  one  upper 
extremity,  join  to  form  the  descending  aorta. 
Malacarnef  has  described  a  remarkable  case 
of  this  anomaly;  the  aorta  was  of  an  oval 
form  at  its  origin,  its  greater  diameter  being 
to  its  lesser  in  the  proportion  of  three  to  two, 
it  had  five  sigmoid  valves  in  its  interior,  it 
divided  immediately  after  its  origin  into  a  right 

*  Vide  Edinburgh  New  Philosophical  Journal, 
by  Dr.  Jameson,  for  October,  1830. 

t  Osservazioni  in  Chirurgia.     Torino,  1784. 


and  left  trunk,  from  each  of  which  arose  a 
subclavian,  an  external  and  an  internal  carotid : 
after  the  two  trunks  had  run  for  a  space  of 
four  inches  distinct,  they  joined  to  form  the 
descending  aorta.  Hommel,  a  Norwegian  ana- 
tomist,* relates  a  case  in  which  the  transverse 
portion  of  the  arch  of  the  aorta  divided  into 
two  trunks,  one  of  which  passed  before  and 
the  other  behind  the  trachea,  after  which  they 
joined  to  form  the  descending  aorta,  having 
encircled  the  trachea  with  a  sort  of  ring :  this 
anomalous  division  of  the  arch  of  the  aorta  is 
the  more  remarkable  as  it  approaches  the  con- 
dition of  the  vessel  which  is  constant  in  all 
known  reptiles.  2d.  The  arch  of  the  aorta  is 
sometimes  absent,  in  consequence  of  the  vessel 
dividing,  immediately  after  its  origin,  into  two 
great  trunks,  one  of  which  gives  off  the  arte- 
ries of  the  head  and  upper  extremities,  whilst 
the  other  becomes  the  descending  aorta.f  This 
distribution  is  similar  to  that  in  the  horse, 
rhinoceros,  and  other  pachydermata,  in  the 
ruminantia,  and  some  of  the  rodentia.  3rd. 
Varieties  in  the  course  of  the  arch  sometimes, 
although  rarely,  occur,  as,  for  instance,  when 
the  arch  of  the  aorta,  instead  of  crossing  to  the 
left  in  the  usual  manner,  curves  over  the  right 
bronchus,  and  gets  to  the  right  side  of  the 
spine,  whence  it  either  immediately  crosses 
behind  the  trachea  and  oesophagus  to  the  left, 
or  continues  its  course  along  the  right  side  of 
the  spine  to  the  lower  part  of  the  thorax ; 
in  cases  of  complete  transposition  of  the  vis- 
cera, where  the  heart  is  in  the  right  side  of  the 
chest,  the  arch  of  the  aorta  is  also  reversed, 
in  which  case  its  thoracic  portion  descends 
along  the  right  side  of  the  spine.|  Instances 
are  recorded  in  which  the  descending  aorta, 
a  little  below  its  arch,  was  very  much  con- 
tracted in  its  area  or  even  completely  obliterated 
for  a  certain  distance,  below  which  it  resumed 
its  full  size :  the  circulation  in  these  cases  was 
carried  on  by  the  anastomosing  of  large  col- 
lateral branches  arising  above  and  below  the 
constricted  or  obliterated  part.§ 

Anomalies  of  the  branches  of  the  aorta  are 
more  frequent :  according  to  Meckel  the 
branches  arising  from  the  arch  deviate  from 
the  normal  condition  in  one  person  out  of 
every  eight.||  The  branches  arising  from  the 
arch  of  the  aorta  present  three  kinds  of  ano- 
maly, which,  as  to  their  frequency,  occur  in  the 
following  order :  1st,  an  increase  in  their  num- 
ber; 2d,  a  diminution;  and  3d,  an  anomaly 
in  the  identity  or  order  of  the  branches  arising 
from  this  part  without  any  increase  or  diminu- 
tion of  their  number.  In  anomalies  of  the  first 

*  Comm.  Noric.  ann.  1737. 

t  Vide  Abhandlungen  des  Josephinischen  Medi- 
cinisch-Chirurgischen  Akademie.  Band,  i.  S.  271. 
Taf.  6.  Wien.  1787. 

$  Meckel  Handbuch  der  Menschlichen  Anatomic. 
Band  iii.  Halle  and  Berlin,  1817.  Abernethy  in 
Phil.  Trans.  1793. 

§  Desault  in  Journal  de  Chirurgie,  torn.  ii. 
Dr.  Goodison  in  Dublin  Hosp.  Reports.  Brasdor 
Recueil  Periodique  de  la  Societe  de  Medecine. 
Paris,  torn.  iii. 

||  Handbuch  der  Menschlichen  Anatomic. 
Band  iii.  Halle  and  Berlin,  1817. 


AORTA. 


191 


kind,   the    number   of  branches   is   most  fre- 
quently increased  to  four,  by  the  left  vertebral 
arising  from  the  arch  between  the  left  carotid 
and  left  subclavian,  as  in  the  phoca  vitulina ; 
next  to  this  in  frequency  is  the  instance  of  the 
inferior  thyroid  arising  from  the  arch  between 
the  innominata  and   left  carotid,  then  the  in- 
ternal mammary,    and,   lastly,    the  most   un- 
usual is  the  thymic  artery  :  it  is  more  unusual 
to  find  the  number  of  branches  coining  from 
the  arch  increased  to  four,  in  consequence  of 
the  innominata  being  absent,  the  right  carotid 
and  right  subclavian  arising  separately  ;  in  such 
a  distribution  the  right  subclavian    most   fre- 
quently arises  from   the  left  extremity  of  the 
arch  after  the  left  subclavian ;  it  may,  how- 
ever, be  the  first  branch  of  the  arch  to  the  right, 
or  it  may  arise  between  the  two  carotids,  or, 
as   more    rarely  happens,    between    the    left 
carotid   and  left  subclavian.     The  number  of 
branches   arising   from  the   arch   will    be  in- 
creased to  five  or  upwards,  when  two  or  more 
of  the  above-mentioned  anomalous  branches 
arise  from  it  at  the  same  time.     Of  the  second 
kind  of  anomaly,  or  that  by  diminution  of  the 
number  of    branches,    the    most   frequent   is 
where  these   are   reduced   to   two,    of  which 
there  occur  the  following  varieties :  a.  the  in- 
nominata sometimes  gives  off  the  left  carotid 
as  an  additional  branch,  and  the  left  subcla- 
vian arises  separately,  as  in  many  quadrumana, 
several  of  the  carnivora,  as  the  lion,  cat,  dog, 
\veazel,  several  rodentia,  &c. ;  6.  sometimes  there 
are  two  arteriae  innominatae,  each  dividing  in 
a  symmetrical  manner  into  the  subclavian  and 
carotid  of  its  own  side,  as  in  cheiroptera  and 
the  dolphin  ;  c.  sometimes  when  the  arch  gives 
off  but  two  trunks,  one  of  them  divides  into 
the  two  carotids,  ^nd  the  other  into  the  sub- 
clavians ;    d.   the   right   subclavian  may  arise 
distinct,  and  a  common  trunk  give  off  the  two 
carotids  and  left  subclavian ;   the  origin  of  a 
single   trunk  from  the  arch  of  the  aorta  sup- 
plying  the   arteries   of   the   head   and   upper 
extremities   is  equivalent  to  a  division  of  the 
aorta  into  an  ascending  and  descending  trunk, 
already  noticed.     The  third  kind  of  anomaly 
partakes  of  the  characters   of  the    two   pre- 
ceding, although  the  number  of  branches  is 
the  same  as  in  the  normal  state :  its  varieties 
are,  a,  the  left  vertebral  arising  from  the  arch, 
whilst  the  left  carotid  comes  from  the  inno- 
minata ;  b,  the  two  carotids  may  arise  from  a 
common  trunk  between  the  origins  of  the  right 
and   left  subclavians,   as    in  the  elephant ;  c, 
the   right  subclavian   and   right   carotid   may 
arise  as  distinct  branches,  whilst  the  left  carotid 
and    left   subclavian    come    from   a   common 
trunk,   forming   a  complete  inversion  of  the 
usual  order ;  rf,  the  left  carotid  may  arise  from 
the  innominata,  whilst  the  right  carotid  comes 
from  the  part  of  the  arch  in  the  situation  usu- 
ally occupied  by  the  origin  of  the  left  carotid. 
Anomalies  of  the  branches  of  the  descending 
aorta  are  less  frequent ;  the  following  are  among 
the  more  remarkable :  a,  the   coeliac  and  dia- 
phragmatic may  arise  above  the  diaphragm ; 
one   or  both   of    the  diaphragmatics  may  be 
given  off  by  the  coeliac  ;  sometimes  the  coeliac 


and  superior  mesenteric  arise  by  a  common 
trunk  as  in  the  tortoise;  sometimes  there  are 
two  or  more  renal  arteries  on  one  or  both  sides, 
and  sometimes  the  primitive  iliacs  are  given 
off  much  higher  than  usual,  in  which  case  they 
are  sometimes  connected  by  a  cross  branch 
before  they  divide  into  the  external  and  in- 
ternal iliacs  :  it  sometimes  happens,  when  the 
iliacs  are  given  off  higher  than  usual,  that  the 
inferior  mesenteric  arises  from  the  left  of 
them. 

The  diseased  conditions  of  the  aorta  are 
described  in  the  articles  ARTERY  and  HEART. 
The  aorta,  as  Beclard  remarks,*  is  more  sub- 
ject than  any  other  artery  to  the  ovoid  dila- 
tation in  its  ascending,  and  the  lateral  dila- 
tation in  its  descending  portion ;  it  is  also  very 
subject  to  osseous  or  calcareous  deposits,  to 
fissures  and  ulcerations,  to  tubercles  and  small 
abscesses  in  its  parietes,  and  to  aneurism. 
Wounds  of  the  aorta  are  constantly  mortal. 
Laennec  has  observed  a  particular  lesion  of 
this  vessel ;  it  was  a  fissure  of  the  internal 
and  middle  coats,  from  which  the  external  tunic 
was  extensively  separated  by  a  quantity  of 
blood  which  had  been  effused  between  it  and 
the  middle  tunic.  The  late  Mr.  Shekelton  has 
described,  in  the  Dublin  Hospital  Reports, 
a  form  of  aneurism  of  the  lower  part  of  the 
abdominal  aorta,  in  which  the  blood  forced  its 
way  through  the  internal  and  middle  coats, 
dissected  the  middle  from  the  external  for  the 
space  of  four  inches,  and  then  burst  into  a  lower 
part  of  the  canal  of  the  artery,  forming  a  new 
channel  which  eventually  superseded  the 
old  one,  which  the  pressure  of  the  tumour 
obliterated. 

Granular  excrescences  are  sometimes  formed 
on  the  valves  of  the  aorta,  which   Corvisart 


conjectured  to  be  of  venereal  origin.  The  in- 
ternal tunic  of  the  aorta  sometimes  presents  a 
red  appearance,  not  peculiar,  however,  to  this 
vessel,  and  occurring  in  certain  forms  of  fever. 
Obliteration  or  constriction  of  the  aorta  is  a 
condition  rarely  met  with;  its  existence  may 
be  traced  either  to  pressure  on  the  vessel  from 
without,  morbid  thickening  of  its  coats,  or  the 
formation  of  coagula  internally ;  this  latter 
occurrence  being  most  usually  a  consequence 
of  the  spontaneous  cure  of  aneurism. 

Aneurisms  of  the  aorta  produce  various 
effects  on  surrounding  parts  ;  thus  the  heart, 
lungs,  trachea,  oesophagus,  pulmonary  artery, 
large  veins,  thoracic  duct,  and  the  various 
organs  in  the  abdomen  placed  in  their  vicinity, 
may  suffer  derangement  of  their  functions, 
displacement,  atrophy  or  partial  destruction, 
according  to  the  degree  of  pressure  to  which 
they  are  subjected. 

Aneurisms  occurring  in  the  ascending  por- 
tion of  the  aorta,  which  is  within  the  pericar- 
dium, are  often  attended  during  life  by  many 
symptoms  very  similar  to  those  of  disease  of  the 
heart  itself,  while  their  pressure  may  produce 
a  diminution  of  the  calibre  of  the  pulmonary 
artery,  obstruct  the  free  passage  of  the  blood 
through  the  vena  cava  superior,  and  even  in- 

*  Dictionnaire  de  Medecinc,  art.  Aorte. 


192 


AORTA. 


terfere  with  the  full  distension  of  the  auricles. 
Aneurisms  of  the  transverse  portion  of  the 
aorta,  when  directed  forwards,  usually  project 
at  the  right  side  of  the  sternum  about  the 
second  intercostal  space  :  when  the  sac  extends 
upwards  towards  the  neck,  it  frequently  be- 
comes a  matter  of  extreme  difficulty  to  dis 
tinguish  an  aneurism  of  the  aorta  from  an 
aneurism  of  the  innominata  or  some  other 
large  arterial  trunk  in  the  neighbourhood  ; 
cases  are  on  record,  where  the  pressure  of  such 
aneurisms  of  the  aorta  caused  obliteration  of 
the  subclavian  and  common  carotid.  When 
aneurisms  extend  backwards,  they  produce  a 
variety  of  effects,  interfering  with  respiration 
and  deglutition  from  their  pressure  on  the 
trachea  and  oesophagus,  sometimes  producing 
obliteration  of  the  thoracic  duct.  The  pres- 
sure produced  by  aneurisms  of  the  thoracic 
and  abdominal  aorta  occasionally  cause  ab- 
sorption of  the  bodies  of  the  vertebrae,  and  give 
rise  to  an  appearance  not  very  dissimilar  to 
that  produced  by  caries. 

Aneurisms  of  the  arch  of  tj^j  aorta  do  not 
so  often  terminate  fatally  by  making  their  way 
through  the  anterior  parietes  of  the  chest,  and 
opening  externally  as  by  bursting  internally : 
when  they  occur  in  that  part  of  the  arch  of  the 
aorta  covered  by  the  pericardium,  they  most 
usually  burst  into  the  sac  of  that  membrane ; 
cases  are  recorded  in  which  aneurisms  of  the 
aorta  have  burst  into  the  pulmonary  arterv,* 
or,  taking  a  direction  backwards,  have  opened 
into  the  trachea,  oesophagus,  or  the  substance 
of  the  lungs.  Aneurisms  of  the  thoracic  por- 
tion of  the  aorta  sometimes  burst  into  the  left 
pleura,  sometimes  into  the  posterior  medi- 
astinum :  they  have  been  known  to  point  at  the 
left  side  of  the  spine,  after  having  caused  ab- 
sorption of  the  heads  of  the  ribs  and  sides 
of  the  bodies  of  the  vertebrae.  In  two  cases 
observed  by  Laennec  and  Mr.  Chandler,  aneu- 
rism of  the  thoracic  aorta  burst  into  the  spinal 
canal.  Aneurisms  of  the  abdominal  aorta 
most  usually  burst  into  the  cellular  tissue  of 
the  lumbar  regions  behind  the  peritoneum, 
seldom  into  the  sac  of  that  membrane.  An 
aneurism  of  the  abdominal  aorta  has  been 
observed  to  make  its  way  backwards  by  the 
side  of  the  spine,  and  point  in  such  a  situation 
as  to  have  been  at  first  mistaken  for  lumbar 
abscess. 

Branches  of  the  aorta.  I.  Branches  arising 
from  the  arch. — From  the  arch  of  the  aorta 
five  branches  are  given  off;  two  from  its  com- 
mencement, the  coronary  arteries,  and  three 
vessels  of  considerable  size  (jig.  78  a  b  c),  from 
the  upper  part  of  its  transverse  portion  to 
supply  the  head  and  the  upper  extremities. 
The  coronary  arteries  of  the  heart  or  the  car- 
diac arteries  arise  from  the  aorta  close  to  its 
origin,  and  immediately  above  the  free  borders 
of  the  sigmoid  valves ;  they  are  usually  two  in 
number,  one  for  each  ventricle. 

The  right,  anterior    or    inferior    coronary 
artery  is  often  larger,  seldom  smaller  than  the 

*  Dr.  Wells  in  Trans,  of  a  Society  for  Improve- 
ment of  Medical  and  Surgical  Knowledge,  vol.  iii. 


Fig.  78. 


A  B,  arch  of  the  aorta. 
C,  thoracic  aorta. 
I),  abdominal  aorta. 
E,  common  iliac  artery. 
g,  middle  sacial  artery. 

left;  it  arises  from  the  anterior  side  of  the 
aorta  above  the  anterior  sigmoid  valve,  coming 
out  from  between  the  roots  of  the  aorta  and 
pulmonary  artery,  it  passes  downwards  and  to 
the  right  side  in  the  groove  between  the  right 
auricle  and  ventricle,  turns  round  the  right  edge 
of  the  heart  until  it  reaches  the  groove  of  the 
septum  on  the  inferior  surface  of  that  organ, 
when  it  changes  its  direction,  coursing  afong 
that  groove  until  it  arrives  at  the  apex  of  the 
heart,  where  it  anastomoses  with  the  left  coro- 
nary artery ;  in  its  course  it  gives  off  to  the 
right  and  left  many  tortuous  branches  arising 
nearly  at  right  angles,  the  right  branches  are 
smaller  and  go  to  the  right  auricle,  the  left  are 
larger  and  belong  to  the  right  ventricle,  which 
they  traverse  in  a  longitudinal  direction  to- 
wards its  apex.  From  the  origin  of  the  right 
coronary  artery  two  small  branches  are  given 
off,  one  to  the  commencement  of  the  pul- 
monary artery  and  the  surrounding  fat,  which 
anastomoses  behind  the  pulmonary  artery 
with  a  branch  of  the  left  coronary;  the  se- 
cond branch  anastomoses  with  the  bronchial 
arteries. 

The  left  posterior  or  superior  coronary 
artery  arises  between  the  left  auricle  and  the 
posterior  surface  of  the  pulmonary  artery,  de- 


AORTA. 


193 


scending  to  the  left  between  the  left  auricle 
and  pulmonary  artery,  and,  having  reached  the 
groove  at  the  base  of  the  heart,  dividing  into 
two  or  three  branches  ;  one  anterior  longitu- 
dinal descends  along  the  anterior  groove  of  the 
septum  to  the  apex  of  the  heart,  where  it  anas- 
tomoses with  the  termination  of  the  right 
coronary  artery,  with  which  it  holds  frequent 
communication  by  branches  which  it  sends 
over  the  anterior  surface  of  the  right  ventricle, 
while  it  sends  some  large  branches  to  the  left 
ventricle;  this  branch  at  its  commencement 
gives  small  twigs  to  the  aorta  and  pulmonary 
artery.  The  second  branch  of  the  left  coronary 
artery  covered  by  the  great  coronary  vein  passes 
from  right  to  left  in  the  groove  between  the 
left  auricle  and  ventricle,  to  both  of  which  it 
gives  many  branches,  turns  round  the  left 
border  of  the  heart,  changes  its  direction,  and 
descends  by  the  side  of  the  right  coronary 
artery  to  the  apex  ;  the  third  branch  sinks  into 
the  substance  of  the  septum  and  continues  its 
course  to  the  apex;  this  branch  sometimes 
arises  directly  from  the  aorta ;  in  this  latter  case, 
of  course,  there  will  be  three  coronary  arteries 
arising  from  the  aorta;  Meckel  has  once  seen 
four  ;  the  supernumerary  coronary  artery  does 
notarise  above  any  particular  valve,  but  usually 
close  to  the  origin  of  one  of  the  normal 
branches.  It  is  rare  to  find  but  one  coronary 
artery  in  the  human  subject,  which  corresponds, 
according  to  Camper,  with  the  normal  con- 
formation in  the  elephant.  The  three  large 
branches  arising  from  the  transverse  portion 
of  the  arch  of  the  aorta  and  sent  to  the  head 
and  upper  extremities,  will  be  described  in  a 
separate  article. 

II.  Branches  of  the  thoracic  aorta. — These 
may  be  divided  into  anterior  and  lateral.  The 
anterior  branches  are,  the  bronchial,  cesophageal, 
and  posterior  mediastinal.  The  lateral  are  the 
inferior  or  aortic  intercostal  arteries.  The 
bronchial  arteries  are  usually  two  in  number, 
one  for  each  lung ;  sometimes,  however,  there 
are  two  for  each  lung,  and  sometimes  the  right 
and  left  bronchial  arise  from  a  common  trunk, 
which  usually  springs  from  the  first  aortic  in- 
tercostal of  the  right  side. 

The  right  bronchial  artery  most  usually  arises 
from  the  first  aortic  intercostal  artery  of  the 
right  side,  which  supplies  it  after  having  arrived 
at  the  right  side  of  the  spinal  column  behind 
the  oesophagus,  sometimes  it  comes  direct  from 
the  aorta;  it  proceeds  in  a  tortuous  course  under 
the  right  bronchus,  to  the  root  of  the  right  lung, 
after  having  given  small  branches  to  the  oeso- 
phagus, the  pleura,  the  back  part  of  the  peri- 
cardium and  the  bronchial  glands. 

The  left  bronchial  artery  arises  immediately 
from  the  aorta  and  passes  in  front  of  the  oeso- 
phagus to  the  left  bronchus,  to  the  posterior 
side  of  which  it  attaches  itself.  Both  bronchial 
arteries  are  similarly  distributed  through  the 
lungs,  dividing  with  the  bronchi,  along  each 
branch  of  which  they  send  two  or  more  tortu- 
ous twigs.  The  relation  of  the  bronchial  arte- 
ries to  the  other  vessels  of  the  lungs  will  be 
more  particularly  noticed  in  the  article  LUNG. 

The  asophageal  arteries  vary  in  number  from 

VOL.  i. 


two  to  seven  :  they  are  inferior  to  the  bronchial 
in  size :  they  arise  from  the  front  of  the  thoracic 
aorta,  and  are  distributed  to  the  oesophagus,  on 
which  they  anastomose  freely  with  descending 
branches  of  the  inferior  thyroid  from  above,  in 
the  middle  of  the  oesophagus  with  the  bronchial, 
and  below  with  branches  of  the  phrenic  and 
coronary  artery  of  the  stomach, 

The  posterior  mediastinal  arteries  are  nume- 
rous and  small;  they  send  branches  to  the 
oesophagus,  thoracic  aorta,  thoracic  duct,  ab- 
sorbents, and  cellular  membrane  of  the  pos- 
terior mediastinum,  anastomosing  with  the 
bronchial,  oesophageal,  and  some  branches  of 
the  right  thoracic  intercostal  arteries. 

Inferior  or  aortic  intercostal  arteries. — Of 
the  eleven  intercostal  spaces  the  two  superior  are 
mostly  supplied  with  arteries  from  the  superior 
intercostal  branch  of  the  subclavian ;  and  as  the 
first  aortic  intercostal  artery  frequently  supplies 
the  third  arid  fourth  intercostal  spaces,  we  often 
meet  with  but  eight  pairs  of  intercostal  arteries 
coming  immediately  from  the  aorta  (jig.  78,  d). 
The  first  right  aortic  intercostal  is  usually  the 
largest  of  the  series  in  consequence  of  giving 
origin  to  the  right  bronchial ;  the  size  of  the  ifrter- 
costal  arteries  diminishes  in  general  from  above 
downwards.  All  the  intercostal  arteries  arise 
rather  from  the  posterior  part  of  the  aorta,  those 
of  opposite  sides  arising  very  near  each  other, 
and  sometimes  springing  from  a  common  trunk. 
At  first  they  descend  obliquely  on  the  vertebral 
column,  at  an  acute  angle  to  the  trunk  of  the 
aorta.  The  right  intercostal  arteries  are  longer 
than  the  left,  in  consequence  of  the  position  of 
the  thoracic  aorta  on  the  left  side  of  the  spine. 
Each  artery  is  lodged  at  first  in  a  groove  on 
the  side  of  the  body  of  each  vertebra,  enters  the 
intercostal  space  passing  behind  the  ganglia  of 
the  sympathetic  nerve,  and  immediately  divides 
into  two  branches,  one  posterior  or  dorsal,  the 
other  anterior  or  intercostal.  The  posterior 
branch  passes  backwards  through  a  space  above 
the  neck  of  each  rib  and  below  the  tran verse 
process  of  the  superior  of  the  two  vertebrse,  with 
which  the  head  of  the  rib  is  articulated  ;  it 
gives  some  branches  to  the  bodies  of  the  ver- 
tebrae, and  in  passing  the  intervertebral  hole 
it  sends  branches  inwards  to  the  spinal  cord, 
which  anastomose  with  the  spinal  arteries.  The 
continuation  of  the  vessel  is  distributed  to  the 
longissimus  dorsi,  sacro-lumbalis,  and  other 
muscles  along  the  side  of  the  spine,  as  well  as 
to  the  integuments  of  the  back.  The  ante- 
rior or  proper  intercostal  branch  is  usually 
larger  than  the  posterior,  and  traverses  the 
intercostal  space.  At  first  it  is  situated  be- 
tween the  pleura  and  external  intercostal 
muscle,  it  shortly  divides  into  two  smaller 
branches,  a  superior  and  an  inferior,  which  get 
between  the  two  layers  of  intercostal  muscles. 
The  inferior  branch,  usually  the  smaller,  runs 
forwards  along  the  superior  border  of  the  in- 
ferior rib,  and  passes  obliquely  over  its  surface 
to  the  periosteum  covering  it.  The  superior 
branch,  larger  than  the  former,  enters  a  groove 
in  the  lower  edge  of  the  superior  rib,  about  its 
angle,  in  company  with  the  intercostal  nerve, 
and  passes  forwards  between  the  two  layers  of 

o 


194 


AORTA. 


intercostal  muscles,  towards  the  junction  of  the 
rib  with  its  cartilage,  where  it  descends  from 
the  rib  towards  the  middle  of  the  intercostal 
space,  and  there  anastomoses  with  the  anterior 
intercostal  arteries  sent  off  from  the  internal 
mammary.  Besides  supplying  the  intercostal 
muscles,  pleura,  and  ribs,  the  intercostal  arteries 
give  several  branches,  which  pierce  the  external 
layer  of  intercostal  muscles,  and  carry  blood 
to  the  muscles  and  integuments  covering  the 
thorax.  The  lower  intercostalsalso  send  branches 
to  the  abdominal  muscles,  diaphragm,  and 
quadratus  lumborum,  which  freely  anastomose 
with  the  internal  mammary,  epigastric,  phrenic, 
lumbar,  and  circumflex  iliac  arteries. 

Anastomoses. — The  intercostal  arteries  have 
a  chain  of  anastomoses  with  each  other  by 
communicating  branches  which  cross  the  heads 
of  the  ribs.  By  this  means  the  superior  freely 
communicate  with  the  subclavian  by  its  inter- 
costal artery.  Inferiorly,  their  anastomosis 
with  the  phrenic,  circumflex  ilii,  and  lumbar 
arteries,  is  equally  free;  internally  they  anasto- 
mose with  the  arteries  of  the  spinal  cord,  and 
in  front  with  the  internal  mammary  and  epi- 
gastric. 

III.  Branches  of  the  abdominal  aorta. — 
They  may  be  divided  into  anterior  and  lateral. 
The  anterior  branches  are,  the  inferior  phrenic, 
cctliac,  superior  and  inferior  mesenteric. 

Phrenic  arteries. — The  phrenic  arteries  are 
two  in  number;  they  arise  from  the  aorta  im- 
mediately after  its  entrance  into  the  abdomen, 
generally  distinct,  sometimes  from  a  common 
trunk,  and  occasionally  one  or  both  arise  from 
the  coeliac  artery,  or  one  of  its  branches.  Each 
phrenic  artery  passes  outwards  in  front  of  the 
crus  of  the  diaphragm,  and  along  the  upper 
edge  of  the  renal  capsule  of  its  own  side.  The 
right  artery  passes  behind  the  vena  cava,  and 
the  left  behind  the  oesophagus.  They  run  on 
the  abdominal  surface  of  the  diaphragm,  and 
at  the  posterior  edge  of  the  cordiform  tendon 
each  vessel  divides  into  an  external  and  an 
anterior  branch.  The  external  branch  supplies 
tiie  fleshy  substance  of  the  ala  of  the  diaphragm, 
and  sends  several  branches  towards  the  external 
attachments  of  that  muscle  which  anastomose 
with  the  lower  intercostal  and  lumbar  arteries ; 
while  the  anterior  branch,  coursing  round  the 
margin  of  the  cordiform  tendon,  supplies  the 
anterior  part  of  the  diaphragm,  and  anastomoses 
with  its  fellow  of  the  opposite  side,  behind  the 
ensiform  cartilage,  sending  forwards  branches 
to  anastomose  with  the  internal  mammary. 

Minute  branches  are  given  oft  by  the  phrenic 
arteries  near  their  origins  to  the  semilunar 
ganglia  and  renal  capsules :  a  small  twig  from 
the  right  phrenic  ascends  along  the  vena  cava 
through  the  diaphragm  to  anastomose  with  the 
comes  nervi  phrenici  of  the  internal  mammary. 
Another  similar  twig,  given  to  the  oesophagus 
by  the  left  phrenic,  while  passing  behind  that 
tube,  anastomoses  with  the  middle  cesophageal 
arteries. 

The  ccdiac  artery,  called,  also,  caliac  axis, 
is  one  of  the  largest  and  shortest  of  the  vessels 
given  off  by  the  abdominal  aorta.  It  generally 
arises  from  the  aorta,  between  the  crura  of  the 


diaphragm  opposite  the  junction  of  the  last 
dorsal  and  first  abdominal  vertebra,  having  the 
renal  capsules  and  semilunar  ganglia  on  either 
side  of  it,  with  the  lobulus  Spigelii  to  the  right, 
the  cardiac  orifice  of  the  stomach  to  the  left, 
the  superior  border  of  the  pancreas  inferiorly, 
and  the  stomach  and  lesser  omentum  in  front : 
it  is  closely  embraced  by  branches  of  the  solar 
plexus. 

The  coeliac  artery,  which  is  often  scarcely 
half  an  inch  in  length,  immediately  divides  into 
three  branches,  the  gastric  or  coronaria  superior 
ventriculi,  the  hepatic,  and  the  splenic,  which 
constitute  the  tripod  of  Haller.  Sometimes  the 
cceliac  axis  gives  off  the  phrenic  and  superior 
capsular. 

Coronary  artery  of  the  stomach. — The  coro- 
nary artery  is  the  smallest  of  the  three  branches 
furnished  by  the  trunk  of  the  caliac ;  it  some- 
times arises  from  the  aorta  itself.  Passing 
upwards,  forwards,  and  to  the  left,  it  arrives 
at  the  cardiac  orifice  of  the  stomach,  from 
which  it  proceeds  forwards  and  to  the  right, 
following  the  direction  of  the  lesser  arch  of 
the  stomach  until  it  arrives  near  the  pylorus, 
where  it  anastomoses  with  the  pyloric  branch 
of  the  hepatic.  When  the  coronary  artery  has 
arrived  at  the  cardiac  orifice  of  the  stomach,  it 
sends  one  or  more  branches  upwards  along  the 
oesophagus  which  supply  that  part  with  blood, 
and  anastomose  with  the  cesophageal  arteries 
from  the  thoracic  aorta :  it  then  sends  branches 
round  the  cardiac  orifice,  which  nearly  encircle 
that  part,  and  ramify  over  the  great  extremity  of 
the  stomach,  where  they  anastomose  with  the  vasa 
brevia  of  the  splenic.  In  its  course  along  the 
lesser  arch  of  the  stomach  the  coronary  sends 
many  branches  over  both  surfaces  of  that  viscus, 
which  anastomose  with  each  other  and  with 
the  right  and  left  gastro-epiploic.  The  ter- 
minal branch  of  the  coronary  which  ends  at 
the  pylorus  is  sometimes  called  superior  pyloric. 
Sometimes  the  coronary  artery  gives  off  the 
right  hepatic  immediately  before  reaching  the 
cardiac  orifice  of  the  stomach. 

The  hepatic  artery  passes  forwards  and  to 
the  right  under  the  lobulus  Spigelii  to  the  neck 
of  the  gall-bladder.  In  this  part  of  its  course 
it  gives  a  few  twigs  to  the  gastro-hepatic  omen- 
tum and  the  inferior  surface  of  the  liver ;  when 
it  reaches  the  pylorus,  it  gives  two  considerable 
branches  called  the  pyloric  and  the  right  gastro- 
epiploic.  The  pyloric  passes  from  right  to  left 
along  the  lesser  arch  of  the  stomach,  where  it 
meets  the  coronary  with  which  it  anastomoses, 
sending  several  branches  over  the  anterior  and 
posterior  surfaces  of  the  stomach  to  anastomose 
with  the  right  gastro-epiploic  artery.  The  right 
gastro-epiploic  artery,  much  larger  than  the 
pyloric,  arises  after  that  vessel ;  it  passes  down- 
wards behind  the  pylorus,  and  arrives  at  the 
greater  arch  of  the  stomach,  along  which  it 
courses  from  right  to  left  and  anastomoses 
with  the  left  gastro-epiploic.  While  passing 
behind  the  pylorus,  it  gives  several  branches  to 
the  pancreas  and  duodenum,  one  of  which, 
somewhat  larger  than  the  rest,  called  pancreatico- 
duodenalis,  lies  concealed  between  the  duo- 
denum and  head  of  the  pancreas,  and  anasto- 


AORTA. 


195 


moses  with  the  branches  which  the  pancreas 
receives  from  the  superior  mesenteric.  As  the 
gastro-epiploic  artery  courses  along  the  greater 
arch  of  the  stomach,  it  gives  off  numerous 
branches,  some  of  which  ascend  on  the  anterior 
and  posterior  surfaces  of  the  stomach,  and 
anastomose  with  the  coronary  and  pyloric ; 
others  descend  in  the  anterior  layer  of  the  great 
omentum :  some  branches  from  these  ascend 
in  the  posterior  layer  of  this  fold  of  membrane 
until  they  reach  the  arch  of  the  colon,  where 
they  anastomose  with  the  colic  branches  of  the 
superior  mesenteric. 

After  having  given  off  these  branches,  the 
hepatic  artery  ascends  towards  the  right  within 
the  capsule  of  Glisson,  in  front  of  the  vena 
porta,  and  to  the  left  of  the  ductus  com  munis 
choledochus.  Having  reached  the  transverse 
fissure  of  the  liver,  it  divides  into  the  right  and 
left  hepatic  arteries  which  enter  the  liver  by 
divisions  corresponding  to  those  of  the  vena 
porta,  the  right  branch  having  previously  given 
off  the  cystic  artery,  which  arises  opposite  the 
junction  of  the  cystic  and  common  hepatic 
ducts,  attaches  itself  to  the  neck  of  the  gall- 
bladder, and  soon  divides  into  two  branches, 
one  of  which  ramifies  over  the  inferior  surface 
of  that  reservoir,  while  the  other  sinks  between 
the  liver  and  the  gall-bladder.  For  further 
particulars  relating  to  the  hepatic  artery  vide 
LIVER. 

The  splenic  is  the  largest  of  the  three  branches 
of  the  cueliac.  Immediately  after  its  origin  it 
passes  with  numerous  contortions  to  the  left, 
behind  the  stomach  and  along  the  superior 
border  of  the  pancreas  to  the  fissure  of  the 
spleen.  In  this  course  it  gives  off  pancreatic 
branches  (pancreatic^  magnee  et  parv<e),  which 
anastomose  with  the  pancreatic  branches  of 
the  right  gastro-epiploic.  It  gives  a  large 
branch,  the  left  gastro-epiploic,  which  some- 
times arises  from  one  of  the  branches  in  which 
the  splenic  terminates.  This  branch  passes 
onwards  to  the  left  until  it  reaches  the  greater 
arch  of  the  stomach,  along  which  it  descends, 
passes  to  the  right  until  it  meets  the  right 
gastro-epiploic,  with  which  it  anastomoses. 
In  its  course  it  gives  off,  like  the  right  gastro- 
epiploic,  superior  branches,  which  pass  over 
the  anterior  and  posterior  surfaces  of  the  sto- 
mach to  anastomose  with  the  branches  of  the 
coronary  and  inferior  branches  which  descend 
in  the  great  omentum,  where  they  have  a  simi- 
lar distribution  with  the  descending  branches 
of  the  right  gastro-epiploic  :  near  the  fissure  of 
the  spleen,  the  splenic  artery  divides  into  five 
or  six  branches,  which  anastomose  by  arches, 
and  enter  the  substance  of  that  organ.  Before 
entering  the  substance  of  the  spleen  these 
branches  give  off  large  vessels,  called  vasa 
brevia,  which  bend  to  the  right,  and  are  dis- 
tributed to  the  great  extremity  of  the  stomach, 
spreading  over  its  anterior  and  posterior  sur- 
faces, where  they  anastomose  with  branches  of 
the  coronary  and  right  gastro-epiploic. 

The  superior  mesenteric  artery,  often  larger 
than  the  coeliac,  arises  from  the  aorta  imme- 
diately after  the  caliac ;  sometimes  from  a  trunk 
common  to  both  vessels,  as  in  the  tortoise.  This 


artery  is  at  first  concealed  by  the  pancreas,  it 
descends  perpendicularly  behind  that  gland 
and  crossing  the  termination  of  the  duodenum 
arrives  at  the  root  of  the  mesentery,  between 
the  two  layers  of  which  it  descends.  In  the 
middle  of  this  fold  of  the  peritoneum  it  forms 
a  considerable  curve,  the  convexity  of  which  is  to 
the  left,  and  directs  its  course  towards  the  ter- 
mination of  the  small  intestine  in  the  right  iliac 
region,  forming  near  its  termination  a  second 
curve,  the  concavity  of  which  is  to  the  left. 
Near  its  origin  this  artery  gives  some  branches 
to  the  duodenum  and  pancreas,  by  means  of 
which  it  anastomoses  with  the  branches  of  the 
hepatic  and  splenic  sent  to  these  organs  :  in  the 
mesentery  it  sends  off  from  its  left  side  the 
arteries  of  the  small  intestines,  and  from  its 
right  the  arteries  which  it  supplies  to  the  jjreat 
intestine. 

Arteries  of  the  small  intestines. — These  arise 
from  the  left  side  of  the  superior  mesenteric, 
varying  in  number  from  fifteen  to  twenty;  the 
superior  are  longer  and  larger,  those  which 
succeed  them  appear  to  diminish  progressively 
in  length  and  size,  they  all  advance  between 
the  two  layers  of  the  mesentery  to  the  concave 
side  of  the  intestine ;  at  a  certain  distance  from 
their  origin  they  divide  into  secondary  branches 
which  diverge  from  each  other  at  acute  angles  ; 
these  secondary  branches  subdivide  into  still 
smaller  branches,  which,  diverging  in  a  similar 
manner,  form  arches  of  anastomoses  with  cor- 
responding branches  of  the  adjoining  arteries  ; 
the  convexities  of  these  arches  are  all  turned 
towards  the  intestine,  and  from  them  numerous 
branches  arise,  which,  by  dividing  and  anasto- 
mosing like  the  larger  trunks,  form  a  second 
series  of  smaller  arches  ;  other  branches  arising 
from  the  convexities  of  these  arches  divide  and 
anastomose  to  form  still  smaller  and  more 
numerous  arches ;  thus  we  have  three,  some- 
times four,  and  occasionally  five  series  of 
arches,  formed  by  the  subdivisions  of  these 
arteries  before  they  reach  the  intestine,  and 
presenting  in  the  mesentery  a  network  with 
large  meshes.  From  the  convexities  of  the 
extreme  arches  which  form  the  outer  border  of 
this  network,  thousands  of  small  arteries  pass 
in  a  straight  direction  to  the  tube  of  the  intes- 
tine ;  these  form  two  series,  an  anterior  and  a 
posterior,  which  apply  themselves  to  the  oppo- 
site surfaces  of  the  intestine,  and  anastomose 
with  each  other  on  its  convex  border.  The 
detailed  description  of  their  further  distribution 
will  come  under  consideration  in  the  article 
INTESTINAL  CANAL. 

Colic  arteries. — The  superior  mesenteric 
sends  off  three,  sometimes  only  two,  branches 
from  its  concavity,  called  right  colic  arteries,  dis- 
tinguished as  superior  or  colicu  media,  middle  or 
colica  dextra,  and  inferior  or  ileo-colic ;  when 
there  are  but  two,  the  superior  and  middle  form 
but  a  single  trunk ;  the  inferior  is  generally 
distinct. 

The  right  superior  colic  or  colica  media  arises 
a  few  inches  distant  from  the  origin  of  the  supe- 
rior mesenteric;  it  passes  forwards  between  the 
layers  of  the  meso-colon  towards  the  middle  of 
the  transverse  colon,  and  divides  into  a  right 

o  2 


196 


AORTA. 


and  left  branch;  the  right  follows  the  right 
part  of  the  transverse  colon,  and  anastomoses 
with  the  superior  branch  of  the  colica  dextra  ; 
the  left  branch  follows  the  left  portion  of  the 
transverse  colon,  and  communicates  with  the 
left  colic  branch  of  the  inferior  mesenteric 
artery. 

The  colica  dextra  or  middle  right  colic  artery 
arises  close  to  the  colica  media,  sometimes  from 
a  trunk  common  to  both,  and  sometimes  from 
the  ileo-colic.  After  its  origin  it  passes  for- 
wards, upwards,  and  to  the  right  in  the  meso- 
colon  towards  the  ascending  colon,  and  divides 
into  two  branches  ;  one  superior  ascends  to 
anastomose  with  the  right  branch  of  the  colica 
media,  the  other  descends  along  the  concavity 
of  the  ascending  colon,  and  communicates  with 
the  ascending  branch  of  the  ileo-colic. 

The  ileo-colic,  coecal,  or  inferior  right  colic 
passes  downwards,  and  to  the  right  towards  the 
eacum,  and  then  divides  into  three  branches ; 
the  first  ascends  in  the  meso-colon,  and  anas- 
tomoses with  the  descending  branch  of  the 
colica  dextra ;  the  second  communicates  in  the 
mesentery  with  the  termination  of  the  superior 
mesenteric ;  and  the  third,  arising  in  the  angle 
between  the  two  preceding,  passes  behind  the 
junction  of  the  ileum  with  the  ccecum  :  at  this 
place  it  gives  off  a  branch  which  forms  a  small 
arch  in  the  mesentery  of  the  vermiform  appen- 
dix, and  then  divides  into  two  branches,  one 
of  which  passes  upwards  on  the  colon,  and  the 
other  descends  on  the  coecum.  The  colic  arte- 
ries, by  their  anastomoses  with  each  other, 
form  arches,  from  the  convexities  of  which, 
turned  to  wards  the  intestine,  numerous  branches 
arise;  each  of  these  again  divides  into  two, 
which  with  the  contiguous  vessels  form  smaller 
arches,  and  straight  branches  finally  arise  from 
the  ultimate  arches,  which,  passing  on  either 
side  of  the  intestine,  include  it  between  them, 
and  anastomose  on  its  convex  edge. 

In  the  foetus  we  have  the  omphalo-mesen- 
teric  artery  arising  from  the  superior  mesen- 
teric ;  this  vessel,  which  passes  along  the  um- 
bilical cord  to  the  vesicula  alba,  becomes 
obliterated  towards  the  end  of  the  second 
month  of  gestation. 

The  iriferior  mesenteric  artery  arises  from  the 
front  of  the  aorta  to  its  left  side,  at  about  an 
inch  or  an  inch  and  a  half  above  the  origins  of 
the  primitive  iliacs ;  it  sometimes  arises  from  the 
left  primitive  iliac,  especially  when  the  aorta 
has  divided  higher  than  usual ;  instances  of  the 
absence  of  this  artery  are  very  rare,  but  interest- 
ing as  presenting  an  example  of  the  normal 
condition  in  birds  and  reptiles,  in  which  the 
inferior  mesenteric  artery  is  much  reduced  in 
size  or  entirely  absent. 

The  inferior  mesenteric  artery  runs  obliquely 
downwards  and  to  the  left,  and  gets  between 
the  layers  of  the  left  iliac  meso-colon,  where  it 
divides  into  many  branches,  distributed  to  the 
left  portion,  and  sigmoid  flexure  of  the  colon 
and  the  rectum ;  the  superior  branches  are  dis- 
tributed to  the  descending  portion  and  sigmoid 
flexure  of  the  colon,  and  are  called  left  colic 
arteries,  while  the  lower  branches  go  to  the 
rectum  under  the  name  of  superior  h<ernor- 


rhoidal  arteries.  The  left  colic  arteries  are 
three  in  number,  the  superior,  middle,  and  in- 
J'erior.  The  superior  left  colic  is  the  largest 
'of  the  three;  it  arises  from  the  inferior  mesen- 
teric immediately  after  its  origin,  passes  trans- 
versely to  the  left,  and  divides  near  the  left 
lumbar  colon  into  two  branches,  one  of  which 
ascends  to  the  transverse  meso-colon,  and 
anastomoses  with  the  colica  media  of  the  supe- 
rior mesenteric;  the  other  branch  descends 
towards  the  left  iliac  meso-colon,  where  it 
anastomoses  with  the  ascending  branch  of  the 
middle  left  colic. 

The  middle  left  colic  is  sometimes  a  branch 
of  the  preceding.  It  divides  into  two  branches; 
one  ascends  along  the  left  colon,  and  anas- 
tomoses with  the  descending  branch  of  the  left 
superior  colic ;  the  other,  inferior,  smaller  com- 
municates with  the  ascending  branch  of  the  left 
inferior  colic. 

The  inferior  left  colic  goes  to  the  sigmoid 
flexure  of  the  colon,  and  soon  divides  into  two 
branches;  one  superior  anastomoses  by  an  arch 
with  the  descending  branch  of  the  preceding, 
and  the  other  inferior  meets  a  branch  of  the 
haemorrhoidal  in  the  meso-rectum.  They  are 
distributed  to  the  intestine  in  a  similar  manner 
with  the  branches  of  the  right  colic  arteries,  as 
already  described. 

When  the  inferior  mesenteric  has  given  off 
the  colic  arteries,  it  diminishes,  takes  a  perpen- 
dicular direction,  and  reaches  the  posteror  sur- 
face of  the  rectum  lodged  between  the  layers  of  the 
meso-recturn,  here  it  takes  the  name  of  superior 
hcemorrhoidal  artery.  It  soon  divides  into  two 
branches,  a  right  and  left,  which  apply  them- 
selves to  the  sides  of  the  rectum,  sending 
branches  backwards  and  forwards  round  that 
intestine,  by  which  they  communicate  with  each 
other,  and  anastomose  below  with  the  middle 
and  inferior  haemorrhoidal  arteries;  some 
branches  anastomose  with  the  lateral  sacral  of 
the  internal  iliac. 

The  lateral  branches  of  the  abdominal  aorta 
consist  of  the  capsular,  renal  or  emulgent, 
spermatic  arteries,  small  twigs  to  the  ureters 
and  adipose  substance  in  the  vicinity  of  the 
aorta,  and  the  four  pairs  of  lumbar  arteries.  For 
an  account  of  the  capsular,  emulgent,  and  sper- 
matic arteries  we  must  refer  to  the  articles 
RENAL  CAPSULE,  KIDNEY,  and  TESTICLE. 

The  lumbar  arteries  are  four  in  number  on 
each  side  (Jig.  78,  f);  they  arise  from  the  lateral 
and  posterior  part  of  the  aorta  nearly  at  right 
angles,  they  pass  outwards  across  the  middle  of 
the  bodies  of  the  four  superior  lumbar  or  abdo- 
minal vertebrae  to  the  roots  of  their  transverse 
processes,  covered  by  the  psoas  muscle  and  the 
crura  of  the  diaphragm.  When  the  lumbar 
arteries  have  reached  the  roots  of  the  transverse 
processes  of  the  lumbar  vertebrae,  they  divide 
each  into  two  branches,  one  posterior  and  the 
other  anterior. 

The  posterior  or  dorsal  branches  are  smaller 
and  pass  backwards  between  the  transverse 
processes  of  the  lumbar  vertebrae,  opposite  the 
intervertebral  foramina,  where  they  each  send  a 
branch  inwards  to  the  spinal  cord  and  cauda 
equina;  they  then  plunge  into  the  substance  of 


AORTA. 


197 


the  great  sacro-lumbar  mass  of  muscles,  in  which 
they  are  lost,  anastomosing  frequently  with  each 
other,  and  with  the  dorsal  branches  of  the  low- 
est intercostal  and  ileo-lumbar  arteries.  The 
continuations  or  anterior  divisions  of  the  lum- 
bar arteries  pass  outwards  between  the  psoas 
and  quadratus  lumborum  muscles,  to  which  they 
give  small  branches,  as  well  as  to  the  diaphragm, 
kidney,  renal  capsule,  and  surrounding  cellular 
membrane ;  they  then  continue  their  course 
forwards  between  the  layers  of  the  abdominal 
muscles,  in  company  with  branches  of  the  lum- 
bar nerves,  and  anastomose  with  the  lower  in- 
tercostals,  mammary,  epigastric,  and  circum- 
flexa  ilii. 

The  middle  sacral  artery  arises  from  the  back 
part  of  the  abdominal  aorta,  immediately  above 
the  origins  of  the  primitive  iliacs,  from  one  of 
which  it  arises  in  some  rare  cases,  it  descends 
exactly  over  the  middle  of  the  anterior  surface  of 
the  bodies  of  the  last  abdominal  vertebra,  false 
vertebrae  of  the  sacrum  and  os  coccygis,  lying 
close  on  the  surfaces  of  those  bones ;  the 
branches  which  it  gives  off  are  distributed  in 
a  lateral  direction ;  the  first  is  the  largest  and  not 
unfrequently  is  the  fifth  lumbar  artery,  the  size  of 
which  sometimes  exceeds  that  of  the  continuation 
of  the  trunk  of  the  middle  sacral  itself.  This 
branch  divides  into  an  anterior  and  a  posterior, 
the  distribution  of  which  is  similar  to  that  of 
the  superior  lumbar  arteries.  Two  transverse 
branches  usually  arise  from  the  middle  sacral 
on  the  body  of  each  false  vertebra ;  these  pass- 
ing outwards  give  branches  to  the  periosteum 
and  the  substance  of  the  sacrum,  anastomose 
with  branches  of  the  lateral  sacral  arteries, 
and  enter  the  anterior  sacral  foramina,  where 
they  give  some  branches  to  the  origins  of  the 
sacral  nerves,  and  emerging  from  the  posterior 
sacral  foramina  are  lost  in  the  muscles  arising 
from  the  back  part  of  the  sacrum  ;  finally,  the 
middle  sacral  terminates  at  the  extremity  of  the 
coccyx  in  small  branches,  which  it  sends  to  the 
rectum  and  surrounding  fat. 

The  middle  sacral  artery  is  sometimes  found 
double;  in  the  foetus  this  artery  is  propor- 
tionally larger  than  in  the  adult,  especially  in 
the  earlier  periods  of  gestation.  In  some  ani- 
mals, the  size  of  the  middle  sacral  artery  is 
scarcely  inferior  to  that  of  the  aorta  itself,  as 
in  the  cetacea  and  fishes.  In  all  animals  fur- 
nished with  tails,  the  size  of  this  artery  bears 
a  constant  relation  to  the  size  of  that  member. 

Aneurism  rarely  affects  any  of  the  branches 
of  the  aorta  above  described  ;  it,  however,  occa- 
sionally occurs  in  the  cceliac  or  mesenteric  arte- 
ries, or  some  of  their  branches.  An  interesting 
case  of  aneurism  of  the  hepatic  artery  unat- 
tended by  pulsation  during  life,  and  which 
produced  jaundice  by  pressing  on  the  ductus 
communis  choledochus,  is  reported  by  Dr.  Wil- 
liam Stokes,  in  the  Dublin  Journal  of  Medical 
and  Chemical  Science,  for  July  1834.  We 
once  witnessed  the  dissection  of  a  female  ajjed 
forty,  under  the  care  of  the  late  Professor  Todd, 
in  the  Surgical  Hospital  of  the  House  of  Indus- 
try in  Dublin,  in  whom  three  distinct  aneurisms 
of  large  size  were  found  in  the  epigastric  region  ; 
one  of  the  hepatic  artery,  which  communicated 


with  that  vessel  by  a  longitudinal  fissure,  and 
which  had  opened  into  the  cavity  of  the  gall- 
bladder; one  of  the  trunk  of  the  coronary  artery 
of  the  stomach,  and  a  third  of  the  splenic 
artery.  A  remarkable  feature  in  this  case,  and 
that  of  Dr.  Stokes,  was  the  absence  of  pulsa- 
tion during  life,  in  consequence  of  which  the 
nature  of  the  disease  was  not  discovered  until 
the  post-mortem  examination  ;  the  above  cir- 
cumstance may  be  attributed  to  the  want  of 
resistance  in  the  surrounding  parts,  and  it  is 
one  which  frequently  obscures  the  diagnosis 
of  abdominal  aneurisms. 

BIBLIOGRAPHY. — Diet,  de  Medecine,  art.  Aorte. 
Beclard,  Elemens  d'anatomie  generate,  8vo.  Paris, 
1823.  Wintringham,  Exper.  inquiry  on  some  parts 
of  the  animal  structure,  8vo.  Lond.  1740.  A. 
Thomson,  in  Jameson's  New  Philosophical  Journal 
for  Oct.  1830.  Malacarne,  Osserv.  in  Cirurgia, 
2  pte,  8vo.  Torino,  1784.  Hommel,  in  Com.  Noric. 
An  1737.  Klintx,  in  Abhand.  d.  Joseph.  Med. 
Chirnrg.  Akademie,  Bd  i.  4to.  Wien.  1787.  Meckel, 
Hanbd.  d.  menschlichen  anatomic,  3  Bde  8vo. 
Halle  and  Berl.  1817.  Abernethy,  Phil.  Trans. 
1793.  Desault,  in  Journal  de  Chirurgie,  t.  ii. 
Goodison,  in  Dub.  Hosp.  Repts.  Brasdor,  in  Rec. 
period,  de  la  Societe  de  Medecine,  t.  iii.  8vo.  Paris. 
Stokes,  in  Dublin  Journal  of  Med.  and  Chem. 
Science,  8vo.  *  *  *  *  Bayer,  Praes.  Tiedemann, 
Diss.  de  ramis  ex  arcu  aortae  prodeuntibus,  4to. 
Salzb.  1817.  Varieties  in  the  number  and  origin 
of  the  principal  branches  of  the  aorta  are  signalized 
by  Tiedemann,  (Tabulae  arteriarum  corporis  bu- 
rn ani  fol.  mag.  Carolirh.  1827,)  in  great  numbers  ; 
also  by  Hunauld  (Mem.  de  Paris  1737  and  1740)  ; 
Neubauer  (De  Art.  thyrodea  ima)  ;  Meckel,  (Epist. 
ad  Haller,  iii.)  ;  Walter  (Mem.  de  Berlin,  1785)  ; 
J.  F.  Meckel  (Tab.  anat.  pathol.  fasc.  ii.  fol.  Lips. 
1817-26);  Haller  (Elementa  Physiologiae,  t.  ii.); 
Meckel  (Pathol.  anatomie,  3  Ph.  8vo.  Leipz.  1812, 
and  in  Archiv.  Bd.  vi.) ;  Huber  (Acta  Helvet. 
viii.)  ;  Loder  (Progr.  de  nonnul.  variet.  arteriarum, 
4to.  Jenae,  1781);  Herold  (Diss.  exh.  obs.  quasd. 
ad  corp.  hum.  partium  struct.  Marburgae,  1812)  ; 
Nevin  (Edinb.  Med.  Comment.  Dec.  2,  vol.9); 
Ryan  (De  quarundum  arteriar.  in  corp.  hum.  dis- 
tributione,  8vo.  Edinb.  1812)  ;  Schoen  (  De  nonnul. 
arteriar.  ortu  et  decursu  abnonni,  8vo.  Hal.  1823)  ; 
Schmiedel  (De  varietatibus  vasor.  pier,  magni  mo- 
menti,  4to.  Erlang.  1745) ;  Ludwig  (Obs.  quaed. 
angiolog.  4to.  Lips.  1764);  Sandifort  (De  notabil. 
vasor.  aberrationibus,  in  Obs.  anat. pathol.  4to.  Lugd. 
Batav.  1774)  ;  Koberwein  (De  vasorum  decursu 
abnormi  ejusque  vi,  &c.  4to.  Viteberg.  1810) ; 
Barkow  (Disq.  circa  originem  et  decursum  arteri- 
arum, 4to.  Lips.  1829)  ;  Otto  (Seltene  Beobach- 
tungen ;  ii  Sammlungen,  4to.  Berl.  1816-24  ;  Ejut 
Handbuch.  d.  patholog.  anatomie,  8vo.  Berl. 
1830— Englished  by  J.  South,  8vo.  Lond.  1831, 
where  there  are  copious  references)  ;  Boehmer  (  De 
4to  et  5to  rarno  ex  arcu  aortae  prod,  in  Haller. 
Disp.  Anat.  Collect,  t.  ii.)  ;  Petsche  (Sylloge  Obs. 
Anat.  Halae,  1736)  ;  Penada  (Saggio  di  Osserv. 
pathol.  anatomiche,  Padova,  1801);  Burns  (Obs. 
on  the  diseases  of  the  heart,  8vo.  Edinb.  1809)  ; 
Nicolai  (De  directione  vasorum);  Biumi  (Obs. 
anatomicae)  ;  Berlin  (Maladies  du  coeur,8vo.  Paris, 
1824)  ;  Bernhard  (Diss.  de  arter.  e  corde  pro- 
deunt.  aberrationibus,  4to.  Berol.  1818)  ;  in  the 
various  systems  of  anatomy,  particularly  those  by 
Heister,  Winslow,  and  'Hildebrandt,  by  Weber, 
in  Morgagni,  (Epist.  &c.  De  Sinubus  arteriae  magnae 
Com.  Bonon.  t.  i.)  Hunauld,  ('Obs.  Anat.  sur  une 
conformation  singul.  de  1'aorte,  Mem.  de  Paris, 
1735);  Fiorati,  (Osserv.  sopra  un  insolita  positione 
dell'aorta,  e  stravagante  origine  desuoiprimi  rami, 
in  Saggi  de  Padova,  t.  i.);  Murray,  (Sonderbane 
Stellung  einiger  grbsscren  Pulsader-stamme,  Ab- 
hand. der  Schwed.  Akad.  Jahr  1768);  Vicq  d'Azyr, 


198 


ARACHNIDA. 


(Manque  de  Fanastomose  qui  reunit  les  deux  arteres 
mesenteriques,  Mem.  de  Paris,  1776)  •,  Du  Verney, 
(Sur  les  vaissaux  omplialo-inesenteriques,  Mem.  de 
Paris,  1700)  ;  Chaussier,  (Sur  les  vaissaux  ompha- 
lo-mesenteriques  ;  Nouv.  Mem.  de  Dijon,  A.  1782. 
Societ.  Philomath,  anil);  and Tyson,( Unusual  con- 
formation of  the  emulgents,  Philos.  Trans.  1678.) 

( J.  Hart.) 

ARACHNIDA;  a§a%»»j,  aranea ;  Eng. 
arachnidans ;  Fr.  arachnides;  Germ.  Spinne ; 
Ital.  Ragni. 

This  class  of  animals  was  for  a  long  time 
confounded  with  that  of  insects,  but  it  has  been 
distinguished  therefrom  by  many  modern  natu- 
ralists, and  more  especially  by  Lamarck,  who 
has  applied  to  it  the  term  l  arachnides/  now 
universally  adopted. 

The  characters  indeed  which  the  arachnidans 
present  are  perfectly  distinct,  and  prevent  them 
from  being  confounded  either  with  crustaceans 
or  insects,  although  one  cannot  avoid  perceiving 
that  they  have  numerous  relations  with  the 
animals  of  these  two  classes,  and  they  are  con- 
sequently placed  in  natural  arrangements  be- 
tween the  crustaceans  and  insects. 

Zoologists  have  assigned  the  following  cha- 
racters as  peculiar  to  and  distinguishing  this 
class. 

Body  divided  into  thorax  and  abdomen; 
apterous.  Legs,  eight  in  the  adult  state.  Head 
continuous  with  the  chest.  Eyes  smooth.  Sex- 
Class. 


ual  orifices  situated  either  on  the  thorax  or  base 
of  the  abdomen. 

To  these  external  characters  may  be  added 
others  derived  from  the  anatomical  conditions 
of  different  organs.  Thus  all  arachnidans  pos- 
sess exclusively  an  aerial  respiration,  either 
effected  by  a  sort  of  lungs,  or  by  means  of 
tracheal  tubes,  as  in  insects.  This  difference 
in  the  respiratory  organs  is  accompanied  with 
one  not  less  marked  in  those  of  circulation; 
for  example,  all  the  pulmonary  arachnidans 
possess  vessels  which  carry  blood,  while,  on 
the  contrary,  all  those  which  have  tracheae  are 
deprived  of  bloodvessels.  Lastly,  the  latter 
species  (or  trachearies)  alone  undergo  metamor- 
phoses analogous,  in  some  respects,  to  those  of 
insects;  while  the  former  (or  pulmonaries) 
suffer  only  changes  of  integument.  We  shall 
treat  further  on  these  peculiarities  hereafter. 

Our  object  here  not  being  to  treat  of  classifi- 
cation, we  shall  refer  the  reader  for  this  subject 
to  the  works  of  Cuvier,  Leach,  Latreille, 
Walcknaer,  Duges,  and  limit  ourselves  at  pre- 
sent to  a  tabular  exposition  of  the  principal 
divisions  and  subdivisions  admitted  in  this 
class  down  to  the  genera  with  which  it  is  most 
essential  to  be  acquainted. 

Latreille,  whose  method  is  that  most  gene- 
rally adopted  by  zoologists  of  every  country, 
divides  the  arachnidans  into  two  great  orders, 
as  follows  : — 


Orders. 

/ Pulmonary  sacs  for  respiration,  6  to  12  ocelli PULMONARIA. 

"  \  Trachea  for  respiration,  not  more  than  4  ocelli TRACHEARIA. 

"Die  same  author  establishes  in  the  first  order  two  families,  which  are  characterized  as  follows  : 

Families. 
.  ARANEID&. 


\st  Order. 


ARACHNIDA 
PULMONARIA. 


Palpi  simple,  pediform;  mandibula  armed  with 
a  moveable  and  perforated  claw,  emitting  a 
poisonous  liquid 

Abdomen  inarticulate,  terminated  by  spinnarets 

Palpi  produced,  cheliform,  or  shaped  like  pin- 
cers   _„. 

Mandibula  provided  with  a  moveable  digit  . . 
^Abdomen  articulate,  without  spinnarets 


.PEDIPALPI. 


M.  Walcknaer,  who  has  made  a  special 
study  of  the  family  of  araneida  or  spinning 
arachnida,  and  who  has  published  many  works 
on  their  methodical  distribution  and  their  habits 


of  life,  has  very  recently  considered  them  with 
the  express  view  of  arriving  at  a  natural  arrange- 
ment of  them ;  the  result  of  his  labour  may  be 
seen  in  the  following 


ARACHN1DA. 


si  I 


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200 


ARACHNIDA. 


ARACHNIDA. 


201 


Of  the  external  covering  or  tegumentary 
system. — Although  the  external  covering  of  the 
arachnidans  varies  in  consistence,  according  to 
the  part  of  the  body  which  is  examined, 
yet  it  may  be  said  in  general  to  be  more  or 
less  soft,  rarely  acquiring  the  solidity  of  the 
integument  of  certain  insects,  and  still  less 
the  hardness  of  that  of  many  crustaceans.* 
Where  it  is  of  the  greatest  consistency  it  is 
elastic,  of  a.  deep  brown  colour,  and  has  an 
aspect  analogous  to  horn.  In  chemical  com- 
position, however,  it  is  always  widely  different, 
as  has  been  proved  by  the  researches  of  M. 
August  Odier,  and  some  other  chemists.  It 
contains,  in  fact,  a  substance  sui  generis, 
called  *  chitine,'  which  is  insoluble  in  potassa, 
but,  on  the  contrary,  is  soluble  in  warm  sul- 
phuric acid,  does  not  turn  yellow  with  nitric 
acid,  and  does  not  curl  up  when  burnt,  but 
leaves  an  ash,  which,  if  the  part  experimented 
on  is  sufficiently  thick,  preserves  the  form  of 
the  organ. 

The  solidity  of  the  outer  covering  is  gene- 
rally greater  on  the  thorax  than  on  the  abdo- 
men. The  genera  scorpio,  phrynus,  theli- 
phojius,  and  phalangium,  afford  an  exception 
to  this  rule,  the  rings  of  the  abdomen  being 
distinct  and  solid,  especially  on  the  dorsal 
aspect. 

In  the  spiders  properly  so  called,  (aranea,) 
and  in  the  greater  number  of  the  mites  (acari), 
the  skin  of  the  abdomen  is  very  soft,  coria- 
ceous, papiraceous,  or  even  membranous, 
transparent,  and  susceptible  sometimes  of  be- 
ing greatly  extended.  It  is  on  this  account 
that  the  abdominal  segment  of  the  body  shrinks 
and  loses  its  form  after  death,  and  from  the 
transparency  of  the  integuments  the  same 
arachnidans  present  during  lifetime  the  various 
markings  and  lively  colours  which  depend  on 
a  kind  of  pigment  situated  in  the  interior  of 
the  body. 

The  head,  as  we  have  remarked  in  our  ex- 
position of  the  characters  of  the  class,  is  always 
consolidated  with  the  thorax;  this  is  readily 
ascertained  to  be  the  fact  in  scorpions  and 
spiders,  and  in  order  to  express  this  dispo- 
sition, which  obtains  also  in  many  of  the 
Crustacea,  the  two  united  segments  are  termed 
*  cephalo-thorax ;'  the  term  abdomen  is  applied 
to  the  part  properly  so  called,  and  thus  the 
body  of  the  arachnidans  may  be  divided  into 
two  parts.  The  abdomen  may  be  either  sessile 
or  pediculate,  i.e.  it  may  either  inclose  at  its 
anterior  margin  the  posterior  part  of  the  thorax, 
as  in  the  scorpions,  or  it  may  adhere  to  the 
thorax  by  a  very  circumscribed  part  of  that 
margin,  as  in  the  spiders  properly  so  called. 
Anatomically  speaking,  the  abdomen  has  a 
very  simple  structure :  it  is  formed  of  annular 
segments  sometimes  distinct  and  hard,  as  in 
the  scorpions ;  sometimes  blended  together 
and  soft,  as  in  the  spiders  and  mites. 

The  other  division  of  the  body  or  cephalo- 
thorax  is  not  so  simple.  To  facilitate  the  study 

*  This  composition  being  precisely  analogous  to 
that  of  the  integuments  of  insects,  we  shall  treat 
of  it  in  the  article  relating  to  these  animals. 


Pholcus  rivulatus. 


of  this  part  it  is  necessary  to  consider  the 
cephalic  portion  separately  from  the  thoracic 
division.  This  it  is  easy  to  do,  where,  as  in 
many  cases,  the  junction  of  the  two  parts  is 
perfectly  distinct,  and  made  obvious  by  the  ex- 
istence of  a  furrow  along  all  the  whole  superior 
part  of  the  line  of  union,  (see  the  traces  of  it 
in  the  thorax  of  a  pholque,  pholcus  rivulatus, 
jig. 79.)  But  in  every  case  the  head  («)  is  recog- 
Fitr  79  nizable  by  constant 

characters:  it  supports 
the  eyes  and  all  the 
pieces  belonging  to 
the  oral  apparatus, 
while  the  thorax  (6), 
on  the  contrary,  gives 
c  insertion  to  the  four 
pairs  of  legs,  which 
on  account  of  their  ex- 
treme length  are  repre- 
sented in  the  figure  as 
truncated. 

The  head  is  often  as  narrow  as  the  chest, 
abruptly  truncated  anteriorly,  and  terminated 
by  a  point  posteriorly,  so  that  it  appears  by  its 
backward  prolongation  to  separate  the  right 
from  the  left  side  of  the  thorax,  and  to  be 
placed  between  them  like  a  wedge,  (as  in 
the  pholcus.)  The  suture  is  very  close,  and 
sometimes  so  far  effaced  that  it  is  no  longer 
possible  to  decide  where  the  head  ter- 
minates and  the  chest  commences.  We 
have  already  observed  that  the  head  sup- 
ports the  eyes  on  its  upper  part,  and  has  the 
oral  instruments  attached  to  its  lower  surface. 
These  consist,  first,  of  a  pair  of  mandibles  or 
forciples;  secondly,  of  a  pair  of  maxilla:; 
thirdly,  of  a  sternal  labium. 

The  number  of  annuli  or  segments  which 
enter  into  the  composition  of  the  head  of  an 
arachnidan  may  yet  be  determined  at  some 
future  period  :  we  have  made  some  attempts 
to  unravel  this  subject,  but  our  observations 
are  not  yet  sufficiently  matured  to  permit  us 
to  decide  so  difficult  a  question. 

Our  researches  on  the  thorax  of  articulate 
animals  have  led  to  more  decisive  results, 
which  we  shall  now  expound,  but  for  the 
complete  understanding  of  which  we  must 
refer  the  reader  to  the  article  INSECTA, 
where  a  more  general  theory  of  the  thorax, 
and  a  description  of  all  the  pieces  that  enter 
into  its  composition  will  be  given.  In  the 
arachnidans  many  of  these  pieces  are  entirely 
wanting;  and  their  thorax  is  consequently 
more  simple  than  that  of  insects :  it  is-  even 
more  simple  than  the  thorax  of  crustaceans, 
to  which,  however,  it  bears  a  great  resemblance 
in  many  points.  If,  for  example,  we  take  a 
large  spider,  as  a  mygale  avicularia,  and  strip 
off  the  hairs  which  clothe  the  thorax,  we  shall 
easily  perceive  a  plate,  or  plastron,  interme- 
diate to  the  right  and  left  series  of  legs.  This 
plastron  is  the  sternum,  or,  to  speak  more  cor- 
rectly, the  union  of  several  sternums,  which, 
were  it  not  for  this  union,  would  manifest 
themselves  as  four  distinct  pieces;  that  is  to 
say,  corresponding  in  number  to  the  pairs  of 
legs  which  arise  from  them.  This  sternal  plas- 


202 


ARACHNIDA, 


Iron  is  distinctly  shewn  in  Jig.  100,  e,  which 
represents  the  inferior  surface  of  the  body  of 
the  house-spider,  (tegenaria  domestica.) 

On  the  upper  surface  of  the  chest  we  find 
another  plate  much  more  extended  than  the 
sternum,  and  joined  anteriorly  with  the  head 
by  means  of  a  fissure  or  triangular  V-shaped 
notch  which  receives  it.  This  plate  or  dorsal 
shield  exhibits  divisions  or  rather  lines  of 
suture  which  the  eye  readily  distinguishes. 
They  represent  arcs  of  circles  arising  from  the 
base  of  the  legs  and  all  ending  in  the  centre 
of  the  thorax,  where  there  is  a  depression 
varying  as  to  extent  and  depth  according  to 
the  individual.  In  other  arachnidans  this 
structure  is  not  so  clearly  shewn  on  account 
of  the  close  union  of  the  different  pieces ;  but 
it  is  easy  to  detect  or  at  least  explain  the  un- 
important modifications  which  obtain  in  these 
cases.  In  the  figure,  which  we  have  taken 
from  Savigny,  of  the  pholcus  rivulatus,  the 
traces  of  the  division  may  be  readily  followed, 
(jig.  79,  &.)  Continued  comparative  researches 
have  convinced  me  that  this  dorsal  plate  of  the 
thorax  of  the  araneida  is  formed,  not  of  the 
dorsal  pieces  of  the  thorax  of  insects,  but  only 
of  the  lateral  pieces  or  those  of  the  flancs. 
For  the  arachnidans  being  deprived  of  wings, 
the  intermediate  thoracic  element  or  tergum, 
so  largely  developed  on  account  of  the  pre- 
sence of  those  organs  in  the  thorax  of  insects, 
being  no  longer  necessary,  has  completely  dis- 
appeared. How  has  this  taken  place?  The 
flancs  (pleura)  which  in  insects  were  diva- 
ricated and  pushed  to  the  sides  by  the  tergum, 
when  that  obstacle  was  removed,  have  mutu- 
ally approximated  and  become  united  toge- 
ther in  the  middle  line,  precisely  at  the  place 
where  the  little  depression  exists  which  we 
have  already  mentioned. 

We  believe  that  we  have  placed  these  facts 
beyond  all  doubt  in  our  '  Researches  on  the 
Thorax  of  Articulate  Animals/  presented  to 
the  Academy  of  Sciences  of  Paris  in  1820.* 
Now  it  is  worthy  of  remark  that  what  has  hap- 
pened to  the  arachnidans,  being  animals  de- 
prived of  wings,  is  also  found  in  the  crusta- 
ceans, which  are  equally  destitute  of  these 
organs.  Only  that  there  exists  in  some  of  the 
latter,  as  the  decapods,  a  vast  carapace  which 
occurs  independently  of  the  flancs,  and  covers 
them.  For  if  the  carapace  is  raised  in  a  crab, 
the  flancs  or  pleurae  are  seen  beneath,  extending 
obliquely  towards  one  another  as  in  the  thorax 
of  a  mygale,  with  this  single  difference,  that 
in  the  cancer,  where  the  carapace  covers  the 
flancs  and  protects  them  as  well  as  the  internal 
soft  parts,  the  pleum  or  side  pieces  remain 
divaricated  and  are  not  joined  at  their  apices 
as  in  the  my  gale. ^ 

*  See  the  Report  by  Cuvier,  in  the  Analysis  of 
the  Works  of  the  Royal  Academy  of  Sciences  for* 
the  year  1820. 

t  We  must  again  refer  to  the  articles  CRUSTACEA 
and  INS  EOT  A  for  the  full  comprehension  of  the  facts 
which  presuppose  an  anatomical  knowledge  of  the 
external  covering  of  the  animals  of  these  two 
classes.  To  those  who  already  possess  that  infor- 
mation 1  shall  observe  that  a  single  piece  of  the 


Digestive  system. — The  arachnidans,  whose 
habits  have  been  made  the  subject  of  obser- 
vation, feed  for  the  most  part  on  animal  matter, 
not  in  a  state  of  decomposition  or  even  re- 
cently dead,  but  in  the  living  state.  They 
either  boldly  seize  their  prey,  which  consists 
of  insects  of  greater  or  less  size,  or  they 
attach  themselves  to  animals  much  larger 
than  themselves,  and  live  parasitically  upon 
their  blood  or  some  other  nutritious  fluid. 
The  latter  species  are  generally  very  minute  : 
many  of  them,  as  the  mites  (acari),  require 
our  best  optical  instruments  for  their  detection. 
The  above  differences  in  habits  of  life  are 
accompanied  with  important  modifications  in 
the  organs  of  nutrition,  and  especially  in  the 
oral  apparatus,  which  we  proceed  to  de- 
scribe. 

In  the  non-parasitic  species,  as  the  pulmo- 
nary and  part  of  the  tracheary  arachnidans, 
the  mouth  consists  essentially,  first,  of  two 
mandibulte  or  forciples  (Jig.  80,  a)  in  close  ap- 

Fig.  80. 


position,  endowed  with  little  lateral  motion, 
but  rather  acting  vertically  and  provided  each 
with  a  hooked  claw  (6),  which,  near  its  point, 
is  perforated,  and  emits  a  poisonous  fluid, 
secreted  by  a  gland,  hereafter  to  be  described. 
In  other  arachnidans  of  the  same  order  the 
mandibula  are  a  species  of  pincers,  one  nipper 
of  which  is  alone  moveable,  as  in  the  scor- 
pions. Secondly,  of  two  maxilla  (e  c),  each 
in  the  form  of  a  more  or  less  flattened  and 
villous  lobe,  provided  with  a  palp  or  jointed 
appendage  (e?)  projecting  more  or  less  from  the 
mouth,  and  terminated  sometimes  by  pincers 
as  in  the  scorpions,  sometimes  by  a  simple 

tlancs  of  insects  (epimera)  forms  the  back-part  of 
the  thorax  of  spiders  ;  the  other  piece  (episternum) 
already  in  a  rudimentary  state  in  the  crustaceans, 
has  completely  disappeared  from  the  thorax  of  the 
arachnidans,  each  segment  of  which  consequently 
consists  only  of  two  pieces,  the  sternum  below,  th« 
epimera  above. 


ARACHNID  A. 


203 


claw,  as  in  the  spiders,  at  least  the  females, 
for  in  the  males  this  palp  is  frequently  the  seat 
of  a  singular  apparatus  (e),  hereafter  to  be 
described.  Thirdly,  of  a  sternal  labiurn  (f), 
which,  as  its  name  implies,  is  inserted  into  the 
sternum,  and  does  not  give  origin  to  any  arti- 
culated appendage  or  palp.  With  respect  to 
the  composition  of  the  mouth  in  the  parasitic 
species,  such  as  most  of  the  mites,  and  we 
may  take  as  an  example  an  argas,  although 
it  is  concealed  under  the  form  of  a  beak, 
sometimes  with  a  sharp 
point,  yet  it  is  essentially 
the  same.  The  principal 
difference  consists  in  the 
dart  -  shaped  mandibles 
(a  «),  being  joined  toge- 
ther so  as  to  form  a  kind 
of  lancet,  the  sides  of 
which  are  sometimes 
denticulated,  so  as  to 
cause  them  to  adhere 
firmly  to  the  flesh  which 
they  have  penetrated. 
The  maxilla  with  their 
palp  (6)  and  the  inferior 
Head  of  a  mite  (Argas.)  la^mm  (c)  are  here  more 

or  less  intimately  blended  together,  so  as  to 
form  a  case  or  sheath.  In  some  instances  the 
maxillary  palp  remains  free,  as  in  the  argas. 

Savigny  admits  that  in  the  interior  of  the 
mouth  of  arachnidans  there  exist  three  pharyn- 
geal orifices,  and  not  a  single  one  as  in  crus- 
taceans and  insects.  These  three  orifices, 
which  are  of  almost  imperceptible  minuteness, 
are  situated  at  some  distance  from  one  another, 
and  disposed  in  a  triangular  form.  He  has 
observed  this  structure  in  spiders,  scorpions, 
and  phalangians :  but  he  represents  only  two 
orifices  in  a  genus  allied  to  galeodes.  Latreille 
denies  the  fact,  and  Treviranus,  in  his  anato- 
mical description  of  arachnidans,  mentions 
only  one  pharyngeal  orifice. 

However  this  may  be,  Savigny  confines  the 
assumption  of  food  in  spiders  to  a  true  suction  : 
"  The  mandibles,"  says  he,  "  do  not  serve  for 
bruising  the  food,  but  for  seizing  it,  and  for 
piercing  and  retaining  it  in  firm  contact  with 
the  maxillae  ;  these  subject  it  to  alternate  pres- 
sure, and  express  the  juices  which  afterwards 
pass  into  the  pharynx."*  This  is  a  matter 
of  daily  observation  when  a  spider  seizes  an 
insect. 

The  intestinal  canal  of  the  arachnidans  is 
always  short,  and  is  never  disposed  in  convo- 
lutions as  in  certain  herbivorous  insects.  This 
disposition  is  in  accordance  with  their  preda- 
ceous  habits,  and  confirms  the  general  rule, 
(but  which  to  our  knowledge  is  not  without 
many  exceptions,)  that  the  intestinal  canal  is 
longer  in  herbivorous  than  carnivorous  animals. 

In  the  spiders,  (araneae,)  and  we  may  take 
the  common  species  (tegenaria  domestica)  as 


*  See  Description  of  Egypt,  Arachnidans,  pi.  8, 
fig.  7 ' ,  E,  y,  y.  Savigny  at  first  admitted  but  two 
pharyngeal  openings,  (Memoir  sur  les  Animaux 
sans  Vertebres,  p.  57)  ;  but  subsequently  admitted 
three. 


Fig.  82. 


Tegennria  domestica. 


an  example,  the  alimentary  canal  (jig.  82 )  com- 
municates with  the  mouth  between  the  maxillae 
(a  a)  by  an  oesophagus,  rather  short  and  of  a  de- 
licate texture  (6).    This  terminates  in  four  sacs 
(c),  which  M.  Treviranus  calls  "  stomach,"  but 
which,  in  our  opinion,  merit  rather  the  name  of 
gizzards;   the  digestive  tube  then    continues, 
as   a  straight   narrow  canal   (d)   of  moderate 
length,  which  dilates  (e)  and  adheres,  by  its 
parietes,  to  a  kind  of  epiploon  filled  with  adi- 
pose granules  (/).   Posteriorly  the  dilated  part 
becomes  stronger  in  texture,  insensibly  con- 
tracts^), then  undergoes  a  second  dilatation  (h) 
before  it  opens  into  the  rectum  (i).     It  is  near 
the  latter  part,  in  a  kind  of  pouch,  that  the 
slender  vessels  open  which  M.  Treviranus  calls 
biliary  vessels,  and  which  he  is,  with  reason, 
surprised  to  see  terminating  in  so  extraordinary 
a  position.     These  vessels,  in  fact,  which  cha- 
racterize so  well  by  their  presence  the  chilific 
stomach  of  insects,  and  are  situated  in  these 
animals  more  or  less  anteriorly,  always  pre- 
ceding the  small  intestines  which  have  a  greater 
or  less  length,  terminate  in  the  spiders  in  the 
rectum  itself,  and  close  to  the  anus. 


204 


ARACHNIDA, 


Now  if  the  observations  of  M.  Treviranus 
are  correct,  and  the  four  vessels  which  he  de- 
scribes are  really  analogous  to  the  biliary  tubes 
of  insects,  we  do  not  hesitate  to  consider  all 
the  part  which  precedes  and  is  intermediate  to 
them  and  the  four  sacs,  as  the  stomach,  or 
chilific  cavity.  It  would  thus  result,  that  the 
tegenaria  domestica  would  be  deprived  of  an 
intestine  properly  so  called,  and  would  pos- 
sess no  part  destined  to  transmit  along  a  greater 
or  less  extent  the  residua  of  the  digestive  pro- 
cess. And,  indeed,  such  residua  must  neces- 
sarily be  very  inconsiderable  in  an  animal 
which  is  sustained  by  juices,  and  these  already 
animalized.  We  are,  indeed,  led  to  this  con- 
clusion by  the  structure  presented  by  the  he- 
mipterous  insects  which  are  nourished,  like  the 
spiders,  by  suction,  and  which  also  have  the 
intestines,  properly  so  called,  so  short  that  the 
biliary  vessels,  which  always  accompany  the 
posterior  extremity  of  the  stomach,  are  found 
close  to  the  anus.  We  may  form  an  idea  of 
this  disposition  by  casting  an  eye  over  the 
beautiful  figures  which  our  friend  M.LeonDu- 
four  has  just  published  in  his  "  Anatomical  and 
Physiological  Researches  on  the  Hemiptera." 


Fig.  83. 


Scorpio. 


In  the  alimen- 
tary canal  of  the 

a  scorpions  the 
biliary  vessels 
d  d  are  inserted 
much  higher  up, 
but  this  is  not 
the  only  pecu- 
liarity which 
the  anatomy  of 
these  animals 
presents.  Their 
digestive  tube 
extends  without 
any  marked  di- 
latation straight 
from  the  mouth 
(a)  to  the  anus 
which  opens  at 
the  extremity  of 

c  the  tail.  It  pre- 
sents in  this 
course  a  very 
singular  struc- 
ture: five  small 
canals  (/>)  go  off 
at  right  angles 
from  either  side, 
above  the  place 
of  communica- 
tion of  the  bili- 
ary vessels,  and 
terminate  by 
ramifying  in 
the  fatty  masses 
which  make  a 
sort  of  epiploon 
(c.)  This  tru- 
ly remarkable 
structure  is  not, 
however,  so  an- 
omalous as 
might  be  sup- 

posed,especially 


if  we  regard  as  ccecums  these  kind  of  lateral  ves- 
sels. For  the  alimentary  canal  presents  a  still 
more  ramified  condition  in  some  crustaceans, — 
we  would  cite  as  an  example  the  argulus  studied 
by  Jurine;*  and  in  another  animal  of  the  same 
class  which  M.  Milne  Edwards  and  myselff 
have  made  known  under  the  name  of  Nicothoe, 
the  intestinal  canal  sends  out  considerable 
lateral  prolongations.  In  the  leech,  and  es- 
pecially the  Clepsina,  there  exist  numerous 
co3cums.  Lastly,  certain  minute  arachnidans 
(acaridae)  are  remarkable  for  analogous  lateral 
dilatations.  It  is  to  be  observed  that  all  these 
beings  are  sustained  by  animal  juices,  and  the 
great  part,  for  the  better  gorging  of  the  same,  are 
fixed  either  momentarily  or  during  their  whole 
life  upon  the  body  of  their  victim. 

We  now  come  to  speak  of  the  epiploon  and 
the  fatty  globules  which  it  contains.  The  fat, 
or  the  substance  which  appears  as  such,  is  ex- 
tremely abundant  in  the  bodies  of  insects  and 
arachnidans.  In  the  latter  it  assumes  the  form 
of  granular  masses  or  globules  of  various  co- 
lours, and  sometimes  these  are  united  together 
by  a  thin  membrane.  In  the  araneae  the  fat  is 
especially  abundant  in  the  abdomen,  of  which, 
indeed,  it  determines  the  form.  The  use  of 
this  fatty  apparatus  cannot  be  mistaken,  and  it 
has  been  placed  beyond  doubt  by  experiment, 
that  it  supplies  the  place  of  nourishment  to  the 
animal,  either  when  the  latter  passes  the  winter 
in  a  state  of  torpidity,  like  the  hibernating  ani- 
mals, or  when  in  particular  seasons  circum- 
stances are  not  favourable  for  catching  prey. 

Respiratory  system. — The  division  which  has 
been  established  in  the  class  Arachnida  of  Pul- 
monaries  and  Trachearies  indicates  that  there 
are  in  these  animals  two  very  different  modes 
of  respiration.  In  both  cases  the  atmosphere 
penetrates  to  the  interior  of  the  body  by  orifices 
situated  on  different  points  of  the  body,  and 
called  stigmata.  The  stigmata  of  the  Pulmo-* 
nary  Arachnidans,  and  especially  those  of  scor- 
pions, are  very  conspicuous ;  they  occupy  the 
inferior  part  of  the  abdomen,  and  are  four  in 
number  on  either  side,  (1,  2,  3,  4,  fg.  84.) 
They  are  in  the  form  of  narrow  fissures,  sur- 
rounded as  in  insects  with  a  circle  of  more 
solid  substance  than  the  rest  of  the  integument, 
and  to  which  we  have  given  the  name  of  pe- 
ritrema. 

In  the  spiders  (araneae)  not  only  do  they 
differ  in  form  but  in  number  and  position. 
Treviranus  counts  four  pairs  in  the  thorax 
above  the  insertion  of  the  legs,  four  pairs  on 
the  upper  part  of  the  abdomen,  and  one  pair 
on  the  lower  surface ;  the  latter  is  the  most 
constant  and  important,  (Jig.  100,  d.) 

The  stigmata  of  the  Tracheary  Arachnidans 
are  less  easy  to  be  distinguished,  more  espe- 
cially on  account  of  the  small  size  of  the 
species  constituting  a  part  of  that  group. 
We  have  here  carefully  figured  them  in  an 
Acaroid  species  (Ixodes  Erinacei),  where  they 
are  situated  below  the  sides  and  on  the  lower 
part  of  the  abdomen,  (Jig.  85,  a,)  in  shape  like 
a  spherical  tubercle,  (Jig.  86,  a,)  perforated  by 

*  Annales  du  Museum,  torn.  viii.    p.  431.    1806. 
t  Annales  de.>  Sciences   Naturelles,    first   series, 
torn.  ix.  pi.  49. 


ARACHNIDA. 


205 


Fig.  84. 


gins  of  which  adhere  to  the  horny  circle   or 
peritrema  of  the  stigma  before  described. 

We  here  subjoin  figures  copied  from  those 
of  Professor  Miiller  of  Berlin,  which  represent 
these  parts  in  a  scorpion.  Fig.  87  shows  one  of 


Fig.  86. 


an  infinite  num- 
ber of  small 
holes,  between 
which  in  the 
centre  we  may 
remark  a  larger 
circular  plate 
(6.)  Each  little 
aperture  is  as  it 
were  stellated  at 
the  margins  (c,) 
by  which  the 
air  penetrates 
the  body  and 
gets  into  the 
...  n  tracheae.  These 
trachese  are  ana- 
logous in  struc- 
ture and  posi- 
tion to  those  of 
insects ;they  are 
elastic,  ramify 
after  the  man- 
ner of  vessels  in  the  interior  of  the  body,  and 
penetrate  to  even  the  minutest  organs. 

With  regard  to  the  internal  respiratory  organs 
of  the  Pulmonary  Arachnidans  they  have  a 
very  different  character ;  presenting  the  ap- 
pearance of  membranous  sacs  formed  by  la- 
mellae applied  to  one  another  like  the  leaves  of 
a  book,  each  of  these  little  receptacles  opens 
into  a  common  cavity,  the  membranous  mar- 


Ixodes  Erinacel 


Fig.  87. 


Fig.  88. 


ddddddddd d  d  d 


the  pulmonary  branchiae  entire,  seen  in  profile : 
a  is  the  edge  by  which  it  adheres  to  the  circum- 
ference of  the  stigma ;  b  the  simple  membrane 
without  folds ;  c  the  folds  or  leaves.  Fig.  88 
shows  a  portion  of  the  same  pulmonary  branchia 
laid  open :  a  is  the  horny  margin  of  the  stigma, 
or  peritrema,  to  which  the  simple  membrane  6 
adheres ;  c  the  common  cavity  into  which  each 
of  the  spaces  opens  which  are  formed  by  the 
laminae. 

These  organs  resemble  closely  in  their  struc- 
ture the  branchial  laminae,  and  hence  Trevi- 
ranus  and  Meckel  compare  them  to  branchiae. 
Miiller  on  the  other  hand  maintains  that  they 
are  lungs,  because,  he  says,  they  can  be  dis- 
tended with  air.  The  name  of  pulmonary 
branchiae,  which  we  have  given  them,  seems  to 
reconcile  the  two  contending  opinions,  although 
we  believe  that  the  distinction  between  lungs 
and  gills  is  in  itself  of  very  slight  importance 
when  applied  to  articulate  animals.  It  is,  for 
example,  quite  impossible  to  establish  such  a 
distinction  in  certain  crustaceans,  as  the  Onis- 
cus,  the  Asellus,  the  Cymothoa,  which  are  all 
provided  with  organs  of  an  analogous  structure, 
although  some  live  in  water,  and  others  in  air 
more  or  less  humid.  Moreover,  certain  crabs, 
as  the  terrestrial  species  called  Cancer  Ucay 
Ruricola,  &c.,  of  Linnaeus,  possess  branchiae 
which  are  much  better  adapted  for  respiration 
in  air  than  in  water.  The  Cancer  Manas,  so 
common  on  our  coasts,  is  almost  in  the  same 
case,  since  it  passes  a  great  part  of  its  life  out 
of  the  sea,  and  it  is  well  known  that  lobsters 
and  shrimps  can  live  a  long  time  out  of  water, 
provided  that  the  air  in  which  they  are  kept  is 
humid.  M.  Milne  Edwards  and  myself  have 
demonstrated,  by  decisive  experiments,  the 
conditions  in  which  the  branchiae  in  these 
animals  act  as  lungs. 

Circulating  system.  —  The  function  of  cir- 
culation, which  is  always  so  intimately  con- 
nected with  that  of  respiration,  presents,  as 
might  be  supposed,  two  different  conditions 
in  the  arachnidans.  Those  which  breathe  by 
means  of  tracheae  have  not  an  apparent  circu- 
lation ;  and  in  this  respect  they  resemble  in- 
sects : — we  attribute  to  them  simply  a  dorsal 
vessel  without  any  ramifications.  Those,  on 
the  contrary,  which  possess  branchial  lungs, 


205 


ARACHNIDA. 


d  • 


'have  an  apparatus  for  circulation  pretty  well 
developed.  It  consists  of  an  elongated  vessel 
placed  immediately  beneath  the  integument 
along  the  middle  line  of  the  dorsal  aspect  of 
the  back,  on  which  account  it  has  received  the 
name  of  dorsal  vessel  (jig.  89).  It  is  kept  in. 
its  situation  by  small  ligaments  or  muscles, 
(a  a),  which  in  insects  are  called  alts  cordis. 
The  texture  of  the  dorsal  vessel  is  membranous, 
and  pretty  firm ;  it  contains  a  colourless  fluid. 
This  heart  is  in  communication  with  numerous 
vessels,  but  hitherto  it  has  not  been  discovered 
which  of  these  terminate  in,  or  which  arise  from 
the  organ,  or,  in  other  words,  it  is  not  known 
by  what  route  the  blood  arrives  at,  or  proceeds 
from  the  heart.  We  believe  that  we  are  able 
to  dissipate  the  doubts  which  still  exist  as  to 
this  subject,  but  before  we  state  our  opinions 
we  shall  speak  of  the  anatomical  disposition  of 
the  apparatus.  Treviranus  has  described  it 
vaguely  in  the  scorpions,  but  has  well  elucidated 
its  structure  in  the  spiders  (araneee),  more  par- 
ticularly in  Club  tone  atrox  and  Tegenaria  do- 
mestica,  Fig.  89.  In  both  these  species  uu- 
merous  vessels  are 
observed  to  arise 
from  the  heart,  es- 
"  pecially  from  its 
posterior  part  (c  c.) 
These  proceed  to 
a  ramify  indefinitely, 
d  distributing  them- 
e  selves  over  every 
organ ;  and  we 
a  have  no  doubt 
e  with  respect  to 
d  their  true  arterial 
nature.  But  in  ad- 
0  dition  to  these  ves- 
sels there  exist  two 
o  others  of  larger 
a  size  (d  d,*)  which 
communicate  in 
a  one  direction  with 
a  the  heart,  in  an- 
other,  by  very  fine 
a  ramifications,  with 
the  pulmonary 
branchiae.  In  Clu- 
bione  atrox  these 
b  two  vessels  do  not 

Tegenaria  domestica. 
branches  in  their  course, 
in  our  mind  but  that  these  vessels  maintain  a 
direct  communication  between  the  heart  and 
respiratory  organs.  The  subjoined  figure 
(Jig.  89)  will  facilitate  the  understanding  of 
these  facts.  It  represents  the  heart  and  its 
appendages  in  the  house-spider,  (Tegenaria 
domestica,)  and  shows  the  two  canals  which 
communicate  with  the  heart  and  receive  the 
small  vessels  (e  e  ee)  that  come  from  the  pul- 
monary branchiae.  Treviranus,  to  whom  we 
owe  these  observations,  has  not,  however,  at- 
tempted to  explain  the  manner  in  which  the 
circulation  takes  place  in  the  arachnidans,  and 
indeed  this  is  to  be  determined  by  physiolo- 
gical experiment  and  riot  by  the  dissection  of 
the  organs  merely.  The  experiments  which  I 


give       out       any 
No  doubt  remains 


have  made,  in  conjunction  with  my  friend  M. 
Milne  Edwards,  on  the  circulation  of  the  crus- 
taceans, enable  me  to  give  a  satisfactory  and 
doubtless  true  explanation  of  that  of  the  arachni- 
dans. The  organs  which  exist  in  these  animals, 
and  we  admit  the  precision  of  the  anatomical  facts 
detailed  by  Treviranus,  are  essentially  the  same 
as  in  the  crustaceans.  We  find  a  heart,  of  the 
nature  of  which  no  one  can  entertain  a  doubt : 
then  there  are  arteries  proceeding  from  the 
heart  and  ramifying  over  every  part  of  the 
body;  lastly,  the  heart  receives  on  each  side 
vessels  which  bring  it  into  communication  with 
the  respiratory  organs.  These  latter  vessels  are 
the  analogues  of  the  branchio-cardiac  vessels 
of  crustaceans.  With  respect  to  veins,  of  which 
the  latter  animals  are  destitute,  they  are  equally 
wanting  in  the  arachnidans,  and  are  doubtless 
replaced  by  cavities  of  an  irregular  form  which 
exist  between  all  the  organs  of  the  body.  Tre- 
viranus, indeed,  has  remarked  in  the  abdomen 
of  Tegenaria  domestica  two  small  intervals 
which  are  discoverable  through  the  integument, 
and  in  which  he  says  the  blood  may  be  ob- 
served to  be  collected.  These  reservoirs  are 
perhaps  the  analogues  of  the  venous  sinuses  of 
the  Crustacea. 

The  nature  of  the  vessels  being  thus  deter- 
mined, it  becomes  easy  to  conceive  how  the 
circulation  takes  place  in  the  arachnidans — 
the  blood,  leaving  the  heart,  is  distributed 
through  all  the  arteries  to  the  different  organs 
for  their  nutrition  :  this  being  effected,  and  the 
nutrient  fluid  being  thereby  converted  into  ve- 
nous blood,  it  begins  to  circulate  through  the 
sinuses  before  mentioned,  and  arrives  by  an 
insensible  course  at  the  pulmonary  branchiae. 
There  it  is  changed  by  contact  with  air  into 
arterial  blood,  and  returns  to  the  heart  by 
means  of  the  branchio-cardiac  vessels  (e  d}  to  be 
finally  again  propelled  through  the  arteries  (c.) 

Thus  the  ascertained  anatomical  facts,  few 
as  they  are,  permit  us  already  to  appreciate  the 
mode  of  circulation  in  the  arachnidans ;  and  we 
repeat  that  it  is  in  every  respect  analogous  to 
the  circulation  in  the  crustaceans. 

Nervous  system. — The  nervous  system  is 
gangliated,  as  in  all  the  articulate  animals; 
but  it  presents  considerable  differences  of  dis- 
position in  the  different  arachnidans :  the 
scorpions  in  this  respect  vary  much  from  the 
spiders. 

In  the  Scorpionidte  we  find  the  following 
structure  (Jig.  90): — the  first  ganglion,  which 
is  commonly  called  the  brain  (a),  and  which 
supplies  the  nerves  to  the  parts  of  the  mouth  (6,c) 
is  intimately  blended  with  the  nervous  mass 
giving  origin  to  the  nerves  of  the  legs  (d).  The 
succeeding  ganglia  are  distinct  from  one  an- 
other, and  are  seven  in  number :  the  Jirst  three 
(1  2  3)  are  situated  in  the  abdomen  proper; 
they  have  this  peculiarity,  that  they  are  united 
together  and  with  the  ganglion,  which  may  be 
termed  cerebro-thoracic,  by  three  instead  of 
two  chords  of  communication  (e),  which  is  the 
number  found  in  all  other  articulate  animals; 
the^bwr  remaining  ganglions  (4567)  occupy 
the  entire  length  of  the  post-abdomen,  or  that 
contracted  portion  of  the  body  which  is  incor- 


ARACIINIDA. 


207 


Fig.  90. 

c  b      be  rectly  termed    the 

tail. 

In  the  Aran- 
a  idee  the  ganglions 
are  fewer  than  in 
the  Scorpionidff. : 
rf  the  first  pair,  or 
that  which  consti- 
d  tutes  the  brain, 
QSg.  9 1,0,)  is  quite 
distinct  from  the 
e  thoracic  ;  these  are 
Jour  in  number  (66) 
but  have  under- 
gone a  remarkable 
fl  degree  of  centrali- 
zation, being  inti- 
mately connected 
together  so  as  in- 
deed to  form  a 
mass  in  which  all 
traces  of  junction 
are  lost>  except  at 
3  the  sides,  which 
have  remained  free 
and  in  the  form  of 
smallconoid  bodies 
directed  outwardly 
so  as  to  resemble, 
in  the  aggregate, 
the  figure  of  a  star. 
From  the  apex  of 
each  of  these  small 
cones  the  nerve  is 
given  off  to  each 
leg.  In  the  abdo- 
men there  does  not 
exist  any  ganglion, 
but  only  a  double 
longitudinal  ner- 
vous cord  (c),which 
swells  out  at  its  ter- 
mination. From 
this  swelling  (d)  a 
great  number  of 
nerves  (ee)  pass  off, 
which  are  distri- 
buted to  all  the 
organs  contained 
in  the  abdominal 
cavity. 

Organs  of  sense. 
— We  have  no- 
thing particular  to 
observe  with  re- 
spect to  the  smell  or  hearing  of  the  arachnidans, 
for  we  are  ignorant  of  the  existence  of  these 
senses  in  the  class,  or  at  least  of  the  parts  of 
the  body  in  which  they  are  seated.  With  re- 
gard to  taste,  the  choice  which  the  arachnidans 
make  of  their  food  sufficiently  indicates  that  it 
exists  in  variable  degree ;  the  organ  is  situated 
probably  at  the  entrance  of  the  pharynx. 
With  regard  to  touch,  the  delicacy  of  that  sense 
is  in  the  ratio  of  the  tenuity  of  the  integument; 
but  the  extremities  of  the  legs,  and  more 
especially  of  the  maxillary  palps  seem  to 
be  expressly  destined  to  bring  the  individual 


\ 


*%•••*. 

into  relation  with  sur- 
rounding objects.  The 
sense  of  sight  is  the 
only  one  respecting 
which  no  doubt  can 
exist ;  particularly  in 
the  species  which  are 
the  most  perfect  of  the 
class,  such  as  the  spi- 
ders, scorpions,  &c. 
The  eyes  belong  to 
that  kind  which  are 
termed  simple,  in  op- 
position to  those  de- 
nominated compound, 
and  which  are  found 
exclusively  in  insects 
and  crustaceans. 

These  simple  eyes 
(ocelli)  in  arachnidans 
are  two,  four,  six,  or 
eight  in  number ;  they 
are  situated  on  the  an- 
terior part  of  the  body 
either  superiorly  or  la- 
terally. With  respect 
to  size  they  differ  not 
only  in  different  spe- 
cies, but  in  the  same 
*  individual,  as  in  the 

Platyscelum,    (Jig.  92,)  and  especially  in  the 

Attus. 

Fig  92. 


In  the  Scorpions  (Jig.  93)  there   are  two 
eyes  (a  a)  situated  on  the  dorsal  aspect  of  the 


Fig.  93. 


cephalo-thorax,  and  closely  approximated  to 
the  mesial  line  :  these  are  of  much  larger  size 
than  the  minute  simple  eyes  (b  6),  which  are 
placed  on  the  sides  and  near  the  outer  margins 
of  the  same  segment.  The  two  mesial  eyes, 
on  account  of  their  size,  have  been  selected  by 
Miiller  for  the  subject  of  his  researches,  which 
he  published  at  Leipsic,  and  which  have  been 
translated  by  extract  in  the  17th  volume  of  the 
first  series  of  the  "  Annales  des  Sciences  Natu- 
relles."  The  following  are  the  principal  re- 


208 


ARACHNIDA. 


suits  of  the  labours  of  this  accomplished  na- 
turalist. 

He  finds  that  each  of  these  simple  eyes  is 
composed,  1st,  of  a  cornea;  2dly,  of  a  crys- 
talline lens;  3dly,  of  a  vitreous  body;  4thly, 
of  a  kind  of  chamber;  5thly,  of  a  choroid; 
6thly,  of  a  retina. 

The  cornea,  as  is  shewn  in  jig.  94,  which 

represents   a  vertical   section   of  the   eye,    is 

smooth  and  con- 

Fig.  94.  vex  externally  («,) 

its  superficies  pre- 
a  senting  none  of 
those  divisions 
which  characte- 
rize the  cornea  of 
the  compound 

«  eyes    of    insects. 

The  internal  sur- 
face is  deeply 
concave,  and  in 
the  hollow  he- 
misphere thus 

formed  is  lodged  the  anterior  part  of  the  crys- 
talline lens.  This  body  (6)  is  of  a  spherical 
figure,  of  a  hard  and  transparent  texture,  resem- 
bling in  these  respects  the  crystalline  lens  of 
Fishes.  Posteriorly  it  rests  upon  but  does  not 
penetrate  the  vitreous  humour.  The  vitreous 
humour  (c)  is  composed  of  a  granular,  soft 
material,  is  larger  than  the  chrystalline,  plano- 
convex anteriorly,  wholly  convex  behind.  As 
the  crystalline  lens  rests  upon  without  sinking 
into  the  vitreous  humour,  there  remains  a  cir- 
cular channel  or  space  filled  with  an  aqueous 
humour,  to  which  the  term  chamber  may  be 
appropriately  given,  and  which  may  be  com- 
pared to  the  posterior  chamber  of  the  eye  of 
some  of  the  vertebrata. 

The  retina  (e}  is  applied  to  the  back  part  of 
the  vitreous  humour,  and  is  in  some  degree  an 
expansion  of  the  optic  nerve  (g).  It  is  lined  by 
a  choroid,  or  membrane  saturated  with  a  co- 
loured matter,  or  kind  of  pigmentum  (/),  which 
is  afterwards  reflected  over  the  anterior  margin 
of  the  plano-convex  surface  of  the  vitreous 
humour  so  as  to  form  there  a  sort  of  pupil,  the 
aperture  of  which  exceeds  the  diameter  of  the 
crystalline,  but  is  less  than  that  of  the  vitreous 
humour.  Such  is  the  somewhat  complicated 
structure  of  one  of  the  large  eyes  of  a  scorpion, 
by  the  knowledge  of  which  physiologists  are 
now  enabled  better  to  understand  the  mode  in 
which  vision  is  effected  in  the  arachnidans. 

Organs  of  secretion. — We  designate  thus  the 
organs  that  emit  outwardly  a  matter  which  is 
sometimes  liquid,  and  sometimes  becomes  con- 
crete by  contact  with  the  atmosphere.  The 
position  of  these  organs  varies;  in  one  case 
they  occupy  the  anterior  part  of  the  body,  in 
another  they  are  observed  at  the  opposite  extre- 
mity. The  nature  and  properties  of  the  matter 
secreted  is  not  less  variable ;  in  some  instances 
it  is  an  irritating  or  poisonous  liquid  which  the 
animal  introduces  by  means  of  a  more  or  less 
sharp  pointed  hook  into  the  interior  of  the  body 
to  which  it  may  be  applied ;  in  other  instances, 
again,  it  is  a  substance  which  is  at  first  in 
a  liquid  state,  but  soon  becomes  solid  in  its 


Fig  95. 


passage  through  a  sort  of  sieve,  or,  if  I  may  be 
permitted  the  comparison,  a  cullender  pierced 
with  excessively  minute  holes.  We  shall  treat 
separately  of  these  two  kinds  of  apparatus. 

Of'  the  apparatus  for  secreting  the  irritating 
or  poisonous  liquid. — Every  one  knows  how 
quickly  a  fly  that  has  been  bitten  by  a  spider 
expires :  the  effect  is  instantaneous.  It  is  by 
means  of  the  mandibulae  or  forciples  that  the 
spider  has  inflicted  the  wound.  These  mandi- 
bulae are  each  armed  with  a  moveable  and  ex- 
tremely sharp  claw,  fjig.  95,  a,)  near  to  the 
point  of  which  is  a  minute  orifice  (6),  from 
which  there  escapes  a  drop 
of  poisonous  liquid,  which 
spreads  itself  over  the  whole 
wound  the  instant  that  it  is 
inflicted.  This  orifice,  which 
from  its  minuteness  is  very 
difficult  to  be  perceived  even 
with  a  high  magnifying  pow- 
er, communicates  with  a  fine 
or  narrow  excretory  canal  (c ), 
situated  in  the  interior  of  the 
-d  mandible  and  given  oft"  from 
the  true  secreting  organ.  This 
gland  is  lodged  in  the  inter- 
space of  the  muscles  of  the 
thorax;  it  is  in  the  form  of 
an  elongated  and  slightly 
curved  vesicle,  the  parietes 
of  which  have  a  singular 
structure.  Treviranus  describes  it  as  consisting 
of  filaments  adhering  together  and  united  by  a 
membrane  so  as  to  resemble  a  spirally  disposed 
band.  This  structure  presents,  he  thinks,  some 
analogy  to  that  of  the  trachea  of  insects.  Ly- 
onnet,  in  his  posthumous  work,  has  described 
this  part  somewhat  differently :  he  considers 
each  little  band  as  being  composed  of  two  sub- 
stances, one  fleshy,  which  contracts  upon  drying, 
the  other  squamous,  which  is  disposed  like  a 
watch-spring,  or  rather  like  Archimedes'  screw, 
and  which  always  remains  in  the  same  state. 
He  supposes  that  these  fibres,  upon  contracting, 
force  the  poisonous  liquid  into  the  excretory 
canal.  Such  a  construction  is  not,  however, 
necessary,  since  it  may  be  readily  conceived 
that  that  vesicle,  being  placed  in  the  midst  of 
very  powerful  muscles,  it  is  sufficient  that  they 
contract  in  order  to  its  compression  and  the 
consequent  propulsion  of  the  fluid  contained 
in  its  interior,  which  probably  the  parietes  have 
secreted. 

This  apparatus  appears  to  us  to  correspond, 
by  its  position,  to  that  which  is  termed,  in  in- 
sects, the  salivary  apparatus,  and  in  silk-worms 
the  silk-glands  :  it  is  even  possible  that  the 
poisonous  fluid  itself,  mingling  with  the  ani- 
mal juices  which  the  spider  introduces  by 
suction  into  its  stomach,  serves  to  facilitate 
digestion. 

Spiders  are  not  the  only  animals  of  their 
class  that  are  provided  with  this  kind  of  organs. 
Scorpions  have  also  a  poison-apparatus,  but  in 
a  very  different  position.  It  is  not  placed  in 
the  mandibles,  but  at  the  posterior  part  of  the 
body,  in  the  last  segment  of  the  tail-like  abdo- 
men. Every  one  is  familiar  with  that  pyrifonn 


ARACHNIDA. 


209 


dilatation  which  the  scorpions  carry  at  the  end 
of  the  tail  ;  it  is  terminated  by  a  little  sharp 
hook  generally  curved  backwards.  Near  its 
termination  there  may  be  observed,  as  in  the 
mandibnlous  hook  of  spiders,  a  very  minute 
orifice,  or,  according  to  some  authors,  two  dis- 
tinct lissnres.  It  is  from  this  part  that  a  lim- 
pid fluid,  having  strongly-marked  poisonous 
qualities,  exudes;  and,  corresponding  to  the  fo- 
ramen within,  there  is  the  neck  of  a  Tittle  blad- 
der which  is  the  true  secretory  organ.  Little  is 
known  respecting  its  structure:  according  to 
the  observations  of  Treviranus  it  is  surrounded 
by  a  horny  substance  and  provided  with  a 
muscle,  which  most  probably  has  for  its  func- 
tion the  compression  of  the  vesicle  and  the 
consequent  expulsion  of  the  poison. 

Apparatus  for  secreting  t lie  fluid  which  con- 
cretes in  the  air. — This  apparatus  is  peculiar  to 
certain  arachnidans  :  it  does  not  exist  in  the 
scorpions  nor  in  many  other  genera  ;  but  when 
present  it  is  always  situated  at  the  posterior 
part  of  the  body.  The  threads  by  which  the 
spiders  suspend  themselves,  and  of  which  they 
spin  their  webs,  are  emitted  from  the  extre- 
mity of  the  abdomen.  There  we  find,  in  the 
vicinity  of  the  anal  aperture,  several  small 
appendages,  which  it  is  important  not  to  con- 
found with  one  another,  (Jig.  9t3.J  Of  these 
there  are  two  which  are  small  articulated  hairy 
Fig.  96.  and  filiform  processes 

(b  b  ;  )*  the  others  are 
spinnarets,  or  the  or- 
gans by  which  the 
c  silky  threads  are  emit- 
ted. Of  the  latter, 
d  four  may  generally  be 
b  counted,  (c  d.}  Their 
structure  is  very  re- 
markable ;  it  has  been 
described  by  many 
anatomists,  and  among  others  by  Lyonnet  in 
his  posthumous  Memoirs.  This  patient  anato- 
mist has  discovered  that  the  surface  of  each  of 
the  spinnarets  is  pierced  by  an  infinite  number 
of  minute  holes,  from  each  of  which  there 
escapes  as  many  little  drops  of  a  liquid,  which, 
becoming  dry  the  moment  it  is  in  contact  with 
the  air,  forms  so  many  delicate  threads.  Im- 
mediately after  the  filaments  have  passed  out 
of  the  pores  of  the  spinnaret,  they  unite,  first 
together,  and  then  with  those  of  the  neighbouring 
spinnarets  to  form  a  common  thread  ;  so  that  the 
thread  of  the  spider,  as  it  is  employed  in  the 
manufacture  of  the  web,  or  such  as  the  creature 
suspends  itself  by  when  hanging  from  one's 

"*  Mr.  Blackball,  who  has  published  some  inter- 
esting observations  on  the  structure  and  functions 
of  spiders  in  the  third  report  of  the  British  Asso- 
ciation (1833),  and  more  at  length  in  a  recent  volume 
of  the  Linnaean  Transactions,  considers  these  pro- 
cesses to  be  also  spinnarets.  They  are  provided 
with  tubes,  which,  arranged  along  the  under  side  of 
the  terminal  joint,  present  the  appearance  of  fine 
hairs  projecting  from  it  at  right  angles ;  if  examined, 
when  in  operation,  by  a  powerful  magnifier,  the 
function  of  these  tubes  may  be  ascertained  without 
difficulty,  as  the  fine  lines  of  silk  proceeding  from 
them  will  be  distinctly  perceived.  Mr.  B.'s 
observations  were  made  on  Agelena  labyrinthica 
(Walck.)— ED. 

VOL.  I. 


finger,  is  composed  of  an  immense  number  of 
minute  filaments,  perhaps  many  thousands,  of 
such  extreme  tenuity  that  the  eye  cannot  detect 
them,  until  they  are  all  twisted  together  into 
the  working  thread.  Lyonnet  has  made  a  still 
more  curious  observation:  he  detected  in  Tcgc- 
naria  civilis  (Walck.)  a  different  anatomical 
structure  of  the  four  spinnarots.  The  pair 
which  is  above  and  a  little  longer  than  the 
other,  presents  on  its  surface  a  multitude  of 
small  perforations,  (flg-  97,J  the  edges  of 
which  do  not  project,  and  which,  therefore, 
Fig.  97.  resemble  a  sieve.  This 

structure  has  also 
been  well  described  by 
Leuwenhoeck,  Roe- 
sel,  Treviranus,  &,c. 
The  other  pair, shorter 
and  lower  than  the 
preceding,  differs  still 
further  by  having  pro- 
jecting or  mamillary 
tubes  independent  of 
the  perforations  which  also  exist  and  are  analo- 
gous to  those  above  de  cribed.  The  tubes  are 
hollow,and  perforated  at  the  extremity  (fig.  98,  a). 
Lyonnet  supposes  that  agglutinating  threads 
issue  from  these  tubes,  while  those  which  are 
Fig.  98.  emitted  from  the  per- 

forations do  not  poss- 
ess that  property.  We 
may  observe,  indeed, 
upon  throwing  a  lit- 
tle dust  on  a  spi- 
der's web,  such  as  the 
circular  one  ofaranea 
diadema,  that  it  ad- 
heres to  the  threads 
which  are  spirally  dis- 
posed, but  not  to  those  that  radiate  from  the 
centre  to  the  circumference;  the  latter  are  also 
stronger  than  the  others. 

.  99.  Internally    there 

a  exists  in  the  abdo- 

men of  spiders  a 
special  secretory  ap- 
paratus, which  con- 
sists of  intestiniform 
canals,  united  toge- 
ther, and  variable  in 
number  and  extent 
according  to  the 
species.  In  Clu- 
bione  atro.r,  they 
consist,  according 
to  Treviranus,  of 
four  vessels,  two 
large  (fig.  99,  a  a) 
and  two  small  (b  b} ; 
near  their  base,  and 
not  far  from  the 
point  where  they  open  into  the  spinnarets,  a 
number  of  small  supplementary  canals  (c  c) 
maybe  observed.  (Fig.  96  represents  the  spin- 
narets in  the  same  species.) 

Generative  system. — In  the  arachnidans  the 
sexes  are  placed,  as  in  insects,  in  different  in- 
dividuals. It  is  not  always  an  easy  matter  to 
distinguish  outwardly  the  male  from  the  female ; 


210 


ARACI-INIDA- 


but  in  some  cases  there  exists  a  well-marked 
character.  The  greater  part  of  the  aranese  of 
the  male  sex  have,  at  the  extremity  of  their 
maxillary  palp,  a  swelling  containing  a  compli- 
cated structure,  which  is  not  found  in  the 
female.  Until  lately  this  protuberance  was 
considered,  notwithstanding  its  anomalous  po- 
sition, as  the  penis  of  the  male;  and  even  now 
this  opinion  is  maintained  by  many  naturalists. 
All  observers  indeed,  both  ancient  and  mo- 
dern, agree  in  stating  that  copulation  takes  place 
by  means  of  this  part.  They  have  repeatedly 
observed  the  fact,  and  have  described  the  pro- 
cess with  all  the  details  that  can  inspire  con- 
fidence in  their  observations.  Nevertheless 
it  appears  to  us  certain,  if  the  anatomical  facts 
we  are  about  to  disclose  are  accurate,  that  there 
is  some  mistake  on  their  part,  and  that  what 
they  have  taken  for  the  act  of  copulation  was 
in  reality  only  a  prelude  to  it.  It  is  indeed 
true  that  the  male  spiders  are  distinguished 
from  the  females  by  the  swelling  at  the  extre- 
mity of  the  maxillary  palp,  and  that  that  swel- 
ling presents  a  very  complicated  structure. 
Treviranus,  Savigny,  and,  earlier  than  these, 
Lyonnet,  have  given  detailed  figures  of  it,  which 
may  be  consulted  with  advantage:  our  descrip- 
tion will  be  after  that  of  Treviranus,  and  from 
observations  made  on  the  common  spider,  Tc- 
genaria  domestica. 

The  male  of  this  species,  when  arrived  at  the 
adult  state,  presents  a  considerable  dilatation  at 
the  extremity  of  its  maxillary  palp  (Jig.  100, «). 
On  carefully  observing  this  swelling,  it  is  per- 


Fig.  100. 


ceived  to  arise  from  the 
penultimate  joint  (6), 
which  is  enlarged  and 
spiny.  The  swelling  it- 
self, or  what  has  been 
termed  penis,  (Jig.  100 
and  Jig.  101,  a,)  is  a  con- 
cave body  from  which 
a  membranous,  vesi- 
cular, and  glandiform 
body  (c)  protrudes,  ter- 
minated by  several 
horny  pieces  (d),  which 
are  curved  and  pro- 
ject but  slightly  in 
this  species,  but  ac- 
quire, in  others,  a  con- 
siderable development, 
and  protrude  in  the  form 
of  long  hooks  having  a 
much  greater  complication  of  structure. 

Fig,  101.  In  order  that  this 

part  should  be  a 
penis,  as  has  been 
supposed,  and  as 
many  naturalists 
still  believe,itought 
to  be  perforated  for 
the  emission  of 
the  prolific  liquor. 
Now,  Treviranus  is 
certain  that  it  is  not 
perforated  by  any 
foramen,  and  also  that  there  does  not  exist  in 
the  interior  of  the  palp  any  excretory  duct 


which  could  have  brought  to  this  part  the  secre- 
tion of  the  testicles.  Lastly,  and  this  proof  is 
still  more  conclusive,  on  examining  carefully 
the  under  surface  of  the  abdomen  of  a  male,  he 
discovered  at  its  base,  i.  e.  at  the  point  where  it 
is  inserted  into  the  thorax,  between  the  aper- 
tures of  respiration,  and  at  the  part  correspond- 
ing to  the  vulvary  opening  of  the  female,  two 
very  small  orifices,  placed  in  a  transverse  fissure, 
which  he  ascertained  to  be  the  true  outlets 
of  the  male  apparatus.  He  found  in  the  inte- 
rior of  the  abdomen  two  cylindrical  dilated 
vessels,  which  he  determined  to  be  the  testes. 
(Fig.  102,  b}  b.)  These  two  organs  open  into 
two  long,  slender,  tortuous, 
Fig.  102.  excretory  canals  (c),  which 

,  terminate  at  the  two  orifices 

of  which  we  have  spoken 
(a),  but  without  the  appear- 
ance of  any  superaddition  of 
a  firm  or  horny  part  that  can 
be  compared  to  a  penis. 
From  this  description  it  is 
certain  that  what  has  been 
regarded  as  the  act  of  copu- 
lation, has  been  only  preli- 
minary, and  that  the  intro- 
duction of  the  extremity  of 
the  maxillary  palp  of  the 
male  into  the  vaginal  aper- 
tures of  the  female  was  for  the 
mere  purpose  of  opening  the 
oviducts  in  order  that  the  ac- 
tual coitus  should  be  effect- 
ed with  facility  and  with- 
c  out  doubt  instantaneously  ; 
which  explains  why  no  ob- 
server has  hitherto  witness- 
ed the  act.* 

The  remarkable  sexual 
differences  which  obtain  in 
a  the  araneae  are  not  found  in 
other  arachnidans.  Thus 
in  the  scorpions  the  maxil- 
lary palps  have  a  similar  organization  in  both 
sexes,  being  terminated  by  pincers,  both  in  the 
male  and  female,  (jig.  84,  b.) 

The  external  aperture  of  the  male  apparatus 
is  placed  behind  the  thorax,  and  manifests  itself 
by  the  presence  of  a  valve  formed  by  two  semi- 
circular pieces  (fig.  84,  c.)  The  internal  struc- 
ture of  these  organs  is  but  imperfectly  known. 
Treviranus  believes  that  he  could  distinguish 
the  testicles  which  terminated  at  the  extremity 
in  a  kind  of  horny  penis.  Leon  Dufour  has 
given  a  more  detailed  description  of  these  or- 
gans, together  with  a  figure  which  represents 
each  testis,  as  being  a  large  network  of  three 
meshes  formed  by  cylindrical  tubes. 

The  male,  like  the  female  scorpion,  presents 
at  the  inferior  part  of  the  body  on  either  side  of 

*  Mr.  Blackwall  denies  the  accuracy  of  Trevi- 
ranus's  opinion,  and  supports  that  of  Lister  and  the 
older  observers,  as  to  the  sexual  function  of  the 
maxillary  palp,  founding  his  remarks  on  observa- 
tions made  on  various  individuals  of  the  genera, 
Epeira,  Theridion,  and  Agelena.  We  must  refer 
for  the  details  to  the  memoir  before  quoted  from  the 
Transactions  of  the  Linnaean  Society. — ED. 


ARACHNIDA. 


211 


the  valve  certain  organs  of  a  singular  structure 
which  are  called  combs,  pectines,  (Jig.  84,  d,) 
on  account  of  the  disposition  of  a  series  of 
small  appendages  of  which  they  are  formed, 
and  which  are  arranged  on  the  lower  surface 
one  beside  the  other,  like  the  teeth  of  a  comb. 
Many  speculations  have  been  offered  respecting 
tlu'ir  uses.  Many  naturalists  believe  that  they 
render  some  assistance  in  the  act  of  impregna- 
tion. Some  suppose  that  they  are  extended 
during  progression,  and  prevent  the  abdomen 
of  the  scorpion  from  trailing  on  the  ground  : 
others,  auain,  regard  them  as  hygrometrical 
organs,  by  means  of  which  the  animal  judges  of 
the  humidity  of  the  atmosphere.  These  are, 
however,  all  mere  gratuitous  hypotheses  un- 
supported by  any  observation  ;  and  the  fact  is 
that  we  have  yet  to  learn  the  use  of  these  pec- 
tinated appendages. 

()/'  the  female  generative  system. — It  has 
been  long  known  that  the  orifices  of  the  gene- 
rative organs  in  female  spiders  are  situated  at 
the  base  of  the  abdomen.  We  observe  on  that 
part  of  the  body  two  distinct  cavities,  (fg.103, 
a,  aj  which  are  closed  by  opercular  pieces  of 


Fig.  103. 


a  more  or  less  solid  texture,  and  it  is  at  this 
part  that  the  oviducts  terminate.  In  the  tege- 
naria  domestica,  these  oviducts  (b,  bj  are  con- 
tinued internally  in  an  insensible  manner  with 
the  ovaries,  which  consist  of  a  kind  of  bags 
(c,  c)  situated  on  each  side  of  the  intestinal 
canal,  and  to  whose  parietes  the  ova  are  attach- 
ed in  a  racemose  manner.  In  the  epeira  diadema 
the  ovaries  are  divided  by  two  longitudinal 
membranous  septa,  and  each  is  again  subdivided 
by  a  transverse  septum.  The  longitudinal  sep- 
tum has  no  orifice,  but  the  transverse  one  is 
perforated.  There  is,  therefore,  no  communi- 
cation between  the  principal  chambers  of  each 
of  these  ovaries,  but  there  is  a  passage  from  the 
anterior  to  the  posterior  division,  and  the  ova 
which  are  in  the  former  must  pass  into  the  lat- 
ter before  being  extruded.  This  structure  ex- 
plains how  it  happens  that  the  epeira  diadema 
lays  its  eggs  at  two  distinct  periods.  Another 
spider  (theridion  quadripunctatum,  \A  alck.) 
presents  a  very  analogous  organization. 

The  female  generative  apparatus  of  scorpions 
has  not  hitherto  been  studied  with  that  degree 
of  care  which  it  deserves ;  and  there  is  a  consi- 


derable difference  among  authors  with  respect 
to  this  subject;  it  therefore  requires  farther  ex- 
amination. Treviranus  and  Leon  Dufour  have 
described  these  organs  as  consisting  of  three 
elongated  tubes  ;  of  these,  two  are  lateral  and 
mutually  communicate  at  their  apices,  the  third 
is  mesial  and  communicates  with  the  lateral  by 
three  branches  which  we  observe  on  either  side. 
All  of  them,  lastly,  terminate  at  the  vaginal 
orifice  which  is  concealed  by  a  more  or  less 
rounded  plate,  and  is  situated  on  the  middle 
line  of  the  body  anterior  to  the  pectines  and 
between  the  coxae  of  the  fourth  pair  of  legs,  at 
the  same  point  where  the  penis  is  placed  in  the 
male  (^.  84,  c./ 

Copulation,  oviposition,  and  development  of 
the  ova.  Metamorphosis,  and  reproduction  of  the 
extremities. — Natural  observers  have  hitherto 
given  but  very  few  details  respecting  the  man- 
ner in  which  the  male  spider  approaches  the 
female,  in  accomplishing  the  sexual  act :  and 
we  have  already  observed  that  they  have  been  de- 
ceived in  considering  a  preliminary  step  as  the 
entire  process.  The  preliminaries  are  accom- 
panied with  very  curious  circumstances,  the 
account  of  which  may  be  found  in  all  the  me- 
moirs and  works  which  treat  of  the  animals  of 
this  class.  It  will  be  there  seen  with  what 
precaution  and  fear  the  male  makes  his  ap- 
proaches to  the  female,  who  is  always  ready  to 
attack  and  devour  him,  whether  before  or  after 
copulation.  The  majority  of  the  arachnidans 
deposit  their  eggs  in  great  numbers.  The 
female  guards  them  with  the  utmost  care,  some- 
times carries  them  about  with  her,  and  always 
prepares  a  silken  nest  for  them  which  is  fre- 
quently covered  with  a  solid  exterior.  Some 
arachnidans,  as  the  scorpions  for  example,  are 
ovo-viviparous ;  the  ova  are  developed  in  the 
interior  of  the  body  of  the  female  who  brings 
forth  her  young  possessing  the  faculty  of  loco- 
motion ;  but  they  rest  for  a  certain  time  at- 
tached to  the  back  of  the  mother,  who  guards 
and  feeds  them,  and  gives  them  a  kind  of  edu- 
cation. 

The  changes  which  occur  in  the  ova  of 
spiders  (araneae)  have  been  studied  vith  mv.ch 
care.  We  are  indebted  to  M.  Heroldt  for 
highly  interesting  observations  on  this  subject, 
published  in  the  work  entitled  "  Exercita- 
tiones  de  animalium  vertebris  carentium  in 
ovo  formatione,"  folio,  Marburg,  1824,  from 
which  an  extract  is  given  in  the  Annales 
des  Sciences  Naturelles,  first  series,  vol.  xiii. 
p.  250.  From  the  importance  of  these  re- 
searches we  here  present  an  analysis  of  them. 

The  exterior  covering  of  the  ovum  is  formed 
by  a  very  delicate  and  transparent  membrane, 
in  the  composition  of  which  no  pore  or  fibre 
can  be  distinguished  on  microscopical  in- 
spection. 

Within  this  membrane  there  is  a  liquid 
matter  in  which  Heroldt  has  distinguished 
several  essential  parts,  which  in  relation  to 
their  functions  appear  to  us  to  correspond  to 
the  vitellus,  the  albumen,  and  the  cicatricula 
of  the  egg  in  birds.  An  idea  of  the  disposi- 
tion and  size  of  these  parts  may  be  formed 
by  inspecting  the  subjoined  figure  (Jig.  104), 

p  2 


212 


ARACHNID  A. 


Fig.  104. 


representing  a  vertical 
section  of  a  fecundated 
ovum  at  the  moment 
ofexclusion,and  before 
any  organ  has  been  de- 
veloped. The  vitellus 
or  yolk  (a)  forms  the 
greatest  part  of  the 
contained  liquid  mat- 
ter, and  the  egg  is 
almost  entirely  filled  by  it :  its  colour  is  gene- 
rally that  of  yellow  ochre,  and  sometimes  has 
a  saffron  tiiv,e.  In  some  species  the  yolk  is 
grey,  white,  or  reddish  brown;  and  in  each 
case  the  colour  of  this  part  determines  the  ge- 
neral tint  of  the  egg.  If  the  yolk  be  consi- 
derably magnified,  it  is  seen  to  be  composed  of 
an  infinite  number  of  minute  globules  of  various 
sizes,  swimming  in  the  albumen,  or  surrounded 
by  it,  and  resembling  so  many  small  yolks. 

The  albumen  (6)  is  a  transparent  crystalline 
liquid,  without  distinct  organical  parts,  and 
consequently  not  presenting  any  globules,  sur- 
rounding the  vitellus  as  far  as  the  cicatricula, 
and  intermediate  in  bulk  or  quantity  to  these. 
If  an  ovum  be  opened,  and  the  liquid  which 
it  contains  be  poured  out  upon  glass,  the  albu- 
men is  seen  to  surround  the  globules  of  the 
vitellus  and  cicatricula  exactly  as  the  serum 
of  the  blood  envelopes  the  crassamentum. 
In  the  interior  of  the  egg  the  albumen  is 
situated,  like  the  cicatricula,  externally  to  the 
yolk,  and  fills  the  interspace  between  the  yolk 
and  the  exterior  membrane  of  the  egg.  It  is 
in  this  interspace  that  the  first  lineaments  of 
the  embryo  appear,  and  here  the  head,  thorax, 
members,  integuments,  and  their  appendages, 
and  all  the  internal  organs,  without  excepting 
the  intestines,  are  successively  developed. 

The  cicatricula  or  germ  (c)  is  the  smallest 
and  most  important  part  of  the  ovum.  It  is 
situated  immediately  beneath  the  exterior  co- 
vering, and  at  the  centre  of  the  circumference 
of  the  egg.  It  is  distinguished  by  the  naked 
eye  in  the  form  of  a  little  white  point.  If  it 
be  examined  with  more  care,  we  perceive  that 
it  is  of  a  lenticular  figure,  and  is  composed 
of  an  innumerable  quantity  of  whitish  granules. 
Under  the  microscope  these  granules  are  seen 
to  be  of  a  globular  figure,  somewhat  similar  in 
this  respect  to  those  of  the  yolk,  but  more  opake, 
and  of  a  smaller  diameter.  When  segregated 
and  diffused  they  present  a  striking  analogy 
to  the  grains  of  pollen,  but  with  this  difference, 
that  the  pollen  of  vegetables  is  composed  of 
vesicles  filled  with  organic  molecules,  whilst 
each  of  these  globules  of  the  cicatricula  must 
be  regarded  as  simple.  The  cicatricula  or 
perm  is  the  centre  of  radiation  of  all  the 
changes  which  take  place  in  the  ovum.  All 
the  parts  which  it  contains  seem  subordinate 
to  it,  as  we  shall  see  by  carefully  tracing  their 
development.  A  remarkable  fact  observed  by 
Heroldt  in  the  ova  of  some  undetermined 
species  of  spiders  is  this,  that  in  place  of  a 
single  cicatricula,  there  appear  to  be  several 
spread  over  different  points  of  the  surface  of 
the  ovum ;  but  these  small  germs  rapidly 
coalesce  into  one  mass,  which  soon  assumes 


.  105. 


the  ordinary  form  of  the  single  cicatricula. 
The  component  parts  of  the  ovum  being  known, 
we  proceed  to  the  metamorphoses  which  they 
undergo  up  to  the  time  when  the  young  spider 
breaks  through  the  shell. 

First  period. — The  im- 
pregnated ovum  being  de- 
posited ,  and  the  te m  perature 
being  favourable,  develop- 
ment commences.  The 
changes  always  begin  at 
the  margins  of  the  cica- 
tricula, which  appear  to  be 
resolved  into  granules,which 
extend  into  the  albumen  and 
vitellus.  The  centre  of  the  germ  remains  the 
same,  the  only  appreciable  difference  is  the 
enlargement  of  its  circumference:  (A,  gives 
the  natural  size  of  the  ovum.) 

Second  period. — The  germ  is  much  larger, 
its  margins  are  dispersed  in  numerous  granules ; 
the  centre  is  not  yet  affected  by  this  tendency 
to  molecular  dispersion,  but  has  undergone 
a  notable  modification.  It  changes  its  situation 
and  begins  to  move  towards  the  extremity  of 
the  ovum,  leaving  in  the  place  which  it  for- 
merly occupied  a  train  of  globules;  it  now, 
to  compare  small  things  with  great,  bears  some 
resemblance  to  a  comet,  the  nucleus  of  which  is 
represented  by  the  centre  of  the  germ;  the  tail, 
which  is  formed  by  the  dispersion  of  the  globules, 
is  transparent,  and  the  vitellus  which  it  covers 
may  be  as  distinctly  seen  through  it  as  the  fixed 
stars  through  the  tail  of  a  comet. 

Third  period. — The   nucleus  of  the   germ 
(jig- 106,  a),  which  has  contimied  to  change  its 
Fig.  106.  place,    is  arrived  near  the 

extremity  of  the  ovum,  but 
has  not  quite  reached  it. 
The  tract  which  it  has 
traversed  is  marked  by  an 
infinity  of  granules,  which 
are  then  so  much  dissemi- 
nated that  they  extend  al- 
most to  the  opposite  extre- 
mity of  the  ovum.  It  is 
then  that  the  kind  of  comet  which  it  represents 
is  seen  at  its  greatest  development,  and  with  all 
the  characters  that  have  been  indicated.  The 
movement  of  the  nucleus  of  the  cicatricula 
authorizes  the  supposition  that  that  body  has 
not,  at  least  at  die  earlier  periods,  a  very 
intimate  connexion  with  the  vitellus. 

Fourth  period. — The  nucleus  of  the  germ 
has  not  gone  beyond  the  point  which  it  had 
attained,  but  it  presents  a  new  change.  The 
molecules  are  disseminated  into  an  infinity  of 
granules,  nothing  remains  of  the  comet  but 
the  tail,  which  is  still  more  extended ;  but 
we  see  then  that  the  granules  dispersed  in 
the  albumen  have  a  tendency  to  reassemble  at 
the  point  where  the  germ  was  originally  situated. 
Fifth  period. — The  germ  of  the  ovum,  which 
appears  to  be  disseminated  in  the  albumen, 
has  undergone  a  very  curious  transformation. 
Its  nucleus  has  disappeared,  all  its  granules 
are  decomposed  into  almost  imperceptible  mo- 
lecules, which,  in  destroying  the  limpidity  of 
the  albumen,  have  given  it  a  clouded  appear- 


ARACHNIDA. 


213 


ance,  through  which,  however,  the  globules 
of  the  vitellus  may  be  distinguished.  A  single 
point  remains  perfectly  transparent,  and  this  is 
observed  at  the  extremity  of  the  egg  (fig.  107, 
«,)  opposite  to  that  which  the  germ  occupied 
Fig.  107.  after  its  displacement. 

Herokltcalls  this  clouded 
a]bumencolliqnamcnt/im. 
Up  to  this  period  the 
vitellus  seems  not  to  un- 
dergo any  change ;  all 
that  has  been  hitherto 
observed  takes  place  in 
the  albumen  and  in  the 
circular  space  between 
the  yolk  and  the  shell. 

Sixth  period.  —  The  colliquamentum,  or 
clouded  albumen,  which  was  extended  over 
the  yolk  so  as  to  conceal  it,  is  now  concen- 
trated upon  the  point  last  occupied  by  the 
nucleus  of  the  germ,  and  has  assumed  a  pearly 
colour  (fig.  108).  Its  consistence  is  pretty 
Fig.  108.  solid  ;  it  is  opake,  so  that 

the  globules  of  the  yolk 
~ a  can  no  longer  be  distin- 
guished through  it,  al- 
though  they  are  elsewhere 
more  conspicuous  on  ac- 
count of  the  retreat  of  the 
clouded  albumen  towards 
this  single  point;  from 
this  moment  the  colliqua- 
mentum,  which  seems  to  have  changed  its 
nature,  receives  a  new  name,  and  is  designated 
by  Heroldt  the  cambium.  The  cambium  covers 
more  than  a  fourth  part  of  the  circumference  of 
the  yolk;  its  form  is  already  pretty  well  marked, 
and  two  parts  may  be  distinguished  ;n  it; 
one  large  (&),  the  other  small  («),  which  are 
separated  by  a  kind  of  contraction.  The  form 
of  the  larger  division  is  elliptical,  and  it  is  in 
its  substance  that  the  thorax,  the  legs,  and  the 
essential  internal  parts  of  the  foetus  will  soon  be 
perceived  to  develope  themselves.  The  smaller 
division  is  of  a  rounded  form,  and  seems,  as  it 
were,  an  appendage  to  the  preceding;  it  is 
destined  to  give  origin  to  the  head,  the  or- 
gans of  sense,  and  the  appendages  of  those  of 
mastication.  So  much  being  premised,  we 
may  call,  with  Heroldt,  the  larger  division 
cambium  thoracicum,  the  lesser  one  cambium 
cephalicurn.  We  may  also,  for  the  better 
comprehension  of  the  changes  which  are  about 
to  succeed  each  other,  divide  the  superficies 
of  the  ovum  into  four  regions.  That  which 
contains  the  cambium  may  be  called  \hepectoral 
region,  the  opposite  portion  may  be  called  the 
dorsal,  and  the  two  intermediate  parts  the 
lateral  regions.  We  may  observe  that  in  other 
species  of  aranese  where  the  ova  are  spherical, 
the  germ  is  at  once  converted  into  colliqua- 
mentum, and  then  into  cambium,  without  a 
change  of  situation.  The  Aranea  c/iadema  offers 
an  example  of  this  circumstance;  in  other  re- 
spects there  is  no  important  difference  observable. 
Seventh  period. — The  two  portions  of  the 
cambium,  the  cephalic  and  thoracic,  have 
as  yet  presented  only  the  appearance  of  an 
opake  and  homogeneous  mass,  but  now  we 


Fig.  109. 


may  distinguish  traces  of  rings,  four  in  number 
on  either  side  ;  these  are  the  rudiments  of  the 
legs.  (Fig.  109,  1,  2,  3,  4.)  They  occupy  the 
lateral  aspects  of  the 
anterior  part  of  the 
ovum  ;  they  are  also 
visible  on  the  pectoral 
region,  towards  which 
they  are  prolonged  in- 
feriorly.  The  extre- 
mity of  the  first  leg  is 
contiguous  to  that  of 
the  opposite  side  ;  but 
the  three  others,  though 
of  greater  length,  yet 
own,  but  leave  a  triangular 


do  not  reach  so  lo\ 


interspace  between  them,  which  is  filled  with 
a  cloudy  and  somewhat  transparent  matter, 
through  which  the  vitelline  globules  are  visible. 
This  triangular  space,  which  is  subsequently 
to  be  covered  by  the  legs,  seems  to  give  origin 
to  the  trunk  and  to  many  parts  contained  in 
the  abdomen.  In  tracing  the  two  portions 
of  the  cambium  through  the  changes  which 
they  have  undergone,  we  find  that  the  thoracic 
portion  is  represented  by  the  legs  and  their 
intermediate  space,  and  that  the  cephalic  por- 
tion is  anterior  to  this.  The  alterations  of  the 
latter  part  are  not  less  remarkable  ;  instead 
of  being  rounded  anteriorly  it  is  truncated,  and 
we  may  perceive  a  ring  at  the  sides,  which  is  not 
divided  on  the  inferior  middle  line  of  the  body, 
and  which  represents  the  maxillary  palps  (6). 
One  may  even  distinguish,  as  if  through  a 
cloud,  the  rudiments  of  the  mandibles.  It 
is  probable  that  all  the  parts  which  appertain 
to  the  head,  as  the  eyes,  the  mandibular 
hooks,  and  the  maxillae,  have  their  limits  well 
defined  from  this  period.  With  respect  to  the 
head,  (ct)  it  is  neatly  separated  from  the  chest  ; 
and  this  fact  it  is  of  importance  to  dwell  on, 
since  in  all  the  full-grown  spiders  the  conflu- 
ence of  the  two  parts  is  most  intimate,  and  their 
original  separation  only  indicated  by  a  groove 
of  greater  or  less  depth.  The  ovum,  also, 
now  presents  some  other  new  appearances; 
these  are  a  kind  of  furrows  or  arched  folds 
(c  c),  which  are  seen  on  the  vitellus  behind 
the  legs  ;  and  which  deserve  attention,  since 
they  indicate  the  formation  of  the  common 
teguments  of  the  foetus.  And  we  must  here 
observe  thaf  the  parts  which  are  already  de- 
veloped have  an  intimate  connection  with  the 
vitellus.  Thus  if  an  ovum  be  opened  with 
all  the  precautions  requisite  for  so  delicate  an 
operation,  and  if  the  matter  of  it  be  extended  on 
a  piece  of  glass,  we  see  that  the  parts  formed 
in  the  cambium  preserve  their  general  figure, 
and  that  the  internal  layer  of  the  mucous  and 
whitish  matter  of  which  it  consists  is  in  intimate 
communication  with  the  vitellus.  It  is  implanted 
upon  the  yolk  just  as  fungi  and  other  parasitic 
plants  are  attached  to  the  trunk  of  a  tree:  the 
yolk,  then,  is  subservient  to  the  nutrition  of 
the  most  exterior  parts  of  the  body. 

Eighth  period.  —  The  exterior  parts  which  are 
developed  in  the  cambium,  viz.  the  feet,  the 
mandibles,  and  the  head,  are  more  neatly  de- 
fined. The  ovum  (Jig.  110)  now  presents  a 


214 


ARAGHNIDA. 


Fig.  110. 


very  important  pecu- 
liarity, but  which  was 
in  some  measure  in- 
dicated   in    the    pre- 
ceding   period.      Its 
size    is    slightly    di- 
minished    anteriorly, 
and  the  vitellus  con- 
sequently is   divided 
* — e  into     two     portions. 
The  smaller  and  an- 
terior part  (a)  is  rea- 
dily    distinguishable 
from  the  dorsal  part 
of  the  foetus,  and  occupies  the  place  which  sub- 
sequently becomes    that  of  the  corslet;    M. 
Heroldt  consequently  terms  it  the  thoracic  re- 
gion.    The  other  part  is  the  abdominal  region, 
which  is  very  conspicuous,  occupies  more  than 
one-half  the  bulk  of  the  ovum,  and  seems  to 
constitute  the  grpatest  portion  of  the  abdomen. 
If  the  inferior  surface  of  the  abdominal  region  be 
examined,  there  will  be  seen,  in  addition  to  a 
srx>t  which  ornaments  that  part,  some  addi- 
tional oblique  and  curved  folds,  which  indicate 
the  formation  of  the  integuments ;  another  and 
a  more  important  change  has  now  taken  place 
on  the  middle  line  of  the  superior  surface;  viz. 
an  obscure  straight  band  (b)  which  commences 
at    the    thoracic-abdominal    constriction,    and 
reaches  to  the  extremity  of  the  ovum,  becoming 
gradually   narrower  in   that   direction.      This 
band,  which  does  not  give  off  lateral  processes 
in  any  part  of  its  course,  is  to  be  considered  as 
the  rudiment  of  the  heart  or  dorsal  vessel.     The 
fluid  which  it  doubtless  contains  in  its  interior 
is  motionless.     Heroldt  thinks  that  the  forma- 
tion  of  the  fluid    is  anterior  to  that  of  the 
parietes  in  which  it  is  enclosed  :  he  also  be- 
lieves that  it  is  the  albumen  which  gives  origin 
to  the  circulatory  apparatus,  and  further  attri- 
butes to  it  the  origin  of  all  the  integuments. 
These   are,  doubtless,  important  questions  to 
solve,  but  as  they  are  the  result  of  speculation 
rather  than  direct  observation,  we  have  deemed 
it  proper  to  omit  the  theories  by  which  they  are 
supported,  and  confine  ourselves  to  a  simple 
enunciation  of  the  facts      The   eyes  (d)  are 
now  distinguishable. 

Ninth  period. — The  ovum  presents  a  more 
sensible  diminution  anteriorly,  and  is  more  dis- 
tinctly divisible  into  two  parts.  The  anterior 
and  narrow  portion  constitutes  the  smaller  ex- 
tremity, and  includes  the  head,  the  thorax,  and 
their  appendages ;  the  other  portion,  which  is 
spherical  and  of  much  larger  size,  constitutes 
the  greater  extremity  and  corresponds  to  the 
abdomen.  At  the  same  time  that  these  modi- 
fications take  place  the  ovum  becomes  slightly 
elongated,  and  all  the  parts  which  can  be  dis- 
tinguished therein  have  proceeded  towards 
their  perfection.  The  legs  now  present  slight 
traces  of  a  division  into  joints,  and  they  have 
increased  so  far  in  length  that  they  cover  almost 
the  whole  of  the  lower  surface  of  the  thorax. 

Tenth  period. — The  small  extremity,  which 
is  still  more  elongated,  is  now  found  to  be  dis- 
tinguished from  the  large  one  by  a  true  conr 
striction,  dividing  the  ovum  into  the  parts  de- 


nominated in  the  perfect  spider  '  thorax'  and 
*  abdomen.'  The  visible  parts  of  the  thorax 
are  the  mandibles,  the  palpi,  and  the  legs ; 
these  latter  appendages  are  folded  upon  the 
chest,  and  have  grown  so  long  as  to  cross  the 
middle  line  of  the  body;  they  are  locked  in  the 
interspaces  of  each  other,  like  the  fingers  when 
the  hands  are  clasped  together.  The  abdomen 
presents  nothing  remarkable,  except  the  elon- 
gated opake  streak  which  exists  along  the  middle 
of  the  inferior  surface  from  the  feet  to  the  termi- 
nation of  the  abdomen,  and  which  was  already 
visible  at  the  preceding  periods.  (Fig.  110,  e.) 
Heroldt  imagines  this  streak  to  be  an  indication 
of  the  development  of  the  internal  parts  of  the 
abdomen,  viz.  the  intestinal  canal,  the  secreting 
vessels  of  the  web,  and  the  genital  organs,  &c. 
In  proportion  as  the  foetus  increases,  the  ex- 
ternal membrane  or  covering  of  the  egg  is  ap- 
plied more  exactly  to  its  body,  and  seems  to 
represent  an  exterior  skin,  of  which  the  young 
spider  soon  divests  itself,  almost  in  the  same 
manner  as  the  caterpillar  sheds  the  skin  in 
which  it  is  enveloped. 

Eleventh  period. — By  the  progressive  in- 
crease of  the  foetus  the  membrane  of  the  egg 
becomes  so  much  stretched,  and  is  applied  so 
exactly  to  the  surface  of  the  body  of  the  animal 
that  the  different  parts  can  be  distinctly  seen 
through  it,  like  the  nymph  or  chrysalis  of  certain 
coleopterous  insects.  The  essential  parts  of  the 
thorax  are  the  head  and  the  feet.  The  head  is  of 
a  white  colour,  and  is  surmounted  by  eight 
brown  streaks  ;  the  legs,  which  are  also  white, 
are  closely  applied  to  the  chest,  with  their  extre- 
mities alternating  with  each  other.  One  may  dis- 
tinguish in  each  a  hip,a  thigh, a  leg,  and  a  tarsus. 
The  articulations  of  the  palps  and  mandibles 
are  also  visible  through  the  general  envelope  of 
the  egg.  The  inferior  streak  of  the  abdomen 
is  much  more  extended,  and  seems  to  be  divi- 
ded into  two  parts,  one  large  and  elliptical  in 
figure,  the  other  small  and  rounded ;  the  latter 
corresponds  to  the  anal  aperture;  at  this  last 
stage  of  the  development,  the  foetus  or  the  im- 
prisoned young  spider,  as  it  may  be  called, 
gives  no  sign  of  motion. 

Exclusion  or  hatching  of  the  spider. — At 
length  the  spider  bursts  the  egg  by  tearing 
through  the  exterior  membrane.  De-Geer*  has 
described  this  phenomenon.  The  outer  mem- 
brane or  pellicle  of  the  ovum  becomes  fissured 
along  the  corslet,  and  the  spider  protrudes  by 
this  aperture,  first  the  head,  the  mandibles,  the 
thorax,  and  abdomen,  after  which  there  remains 
the  more  difficult  operation  of  extracting  the 
legs  and  maxillary  palps  from  that  part  of  the 
outer  membrane  with  which  these  parts  are,  as  it 
were,  enveloped.  This  is  at  length  effected, 
though  slowly,  by  alternately  dilating  and  con- 
tracting the  body  and  legs,  upon  which  the 
animal  is  liberated,  and  capable  of  progression. 
In  proportion  as  the  parts  are  disengaged  from 
the  pellicle,  it  is  pushed  towards  the  extremity 
of  the  legs,  and  is  reduced  to  a  little  white  bag 
which  is  all  that  remains.  Sometimes  the  pel- 
licle is  found  still  slightly  adherent  to  the  ab- 

*  Mem.  sur  Ics  Insectes,  t.  vii.  p   195. 


ARACIINIDA. 


215 


domen,  but  the  spider  soon  entirely  frees  itself 
from  it.  This  is  the  mode  in  which  the  young 
spiders  of  every  species  disembarrass  themselves 
of  the  egg-covering,  and  the  operation  is  analo- 
gous to  that  of  moulting.  This  is,  however, 
only  the  first  birth:  all  the  parts  of  the  spider, 
the  head,  the  jaws,  the  le^s,  the  abdomen,  are 
still  enveloped  by  a  membrane  which  furnishes 
to  each  a  sort  of  sheath.  The  spider  is  embar- 
rassed in  all  its  movements ;  it  changes  its 
situation  with  apparent  pain,  and  is  unable  to 
construct  a  web  and  seize  its  prey  :  it  seems  in- 
deed to  be  stupified  and  indisposed  to  action. 
To  this  end,  and  in  order  to  be  fit  for  locomo- 
tion, it  is  necessary  that  it  should  free  itself  of 
this  other  covering ;  and  it  is  only  then  that  it  can 
be  said  to  see  the  light.  This  last  operation, 
or  as  it  may  be  termed  the  first  moult,  takes 
place  after  a  period,  varying  according  to  the  de- 
grees of  atmospheric  heat  and  moisture.  Some- 
times it  is  observed  within  the  first  week,  at 
ethers  it  is  not  effected  before  the  end  of  several 
weeks.  In  every  instance  the  moult  takes 
place  in  the  woolly  nest  or  general  envelope  of 
all  the  eggs,  and  the  young  spider  does  not 
quit  this  common  nest,  except  in  fine  weather, 
generally  in  the  months  of  May  and  June. 

Before  arriving  at  the  adult  state  the  spider 
changes  its  skin  many  times,  and  even  after  that 
period  it  is  still  subject  to  moults,  which  occur 
every  year  in  the  spring,  and  after  the  exclusion 
of  the  eggs.  Up  to  the  present  time  it  has 
been  admitted  that  the  Arachnidans,  from  the 
moment  of  their  exclusion  to  their  adult  state, 
undergo  no  metamorphosis,  but  are  subject 
only  to  the  moultings  of  which  we  have  just 
spoken.  This  circumstance  has  even  been  em- 
ployed by  zoologists  as  a  character  distinguish- 
ing the  arachnidans  from  the  class  of  insects, 
which  generally  undergo  metamorphoses  in  pas- 
sing through  the  conditions  of  the  larva  and 
chrysalis.  The  observation  holds  good  for  the 
greater  part  of  the  Arachnidans,  but  there  are 
many  of  this  class,  which,  in  passing  to  their 
adult  condition,  undergo  changes  which  cannot 
but  be  compared  with  the  metamorphoses  of 
insects.  Such,  for  example,  are  many  of  the 
acaridff,  upon  which  M.  Duges  has  recently 
fixed  the  attention  of  naturalists.* 

We  cannot  conclude  the  present  article, 
without  briefly  noticing  a  very  curious  phy- 
siological phenomenon  which  has  been  ob- 
served in  the  Arachnidans,  and  which  has 
long  been  noticed  in  the  class  Crustacea : 
we  allude  to  the  faculty  which  these  animals 
possess  of  reproducing  their  limbs  when  these 
have  been  accidentally  lost.  This  property, 
which  belongs  to  the  spiders,  (aranetf,)  was 
generally  doubted,  until  a  distinguished  natu- 
ralist, M.  Lepelletier,  published  the  result  of 
his  experiments ;  the  fact  is  of  too  much  im- 
portance in  science  not  to  be  dwelt  upon  with 
some  detail.  Spiders  which  have  lost  a  limb, 
according  to  this  observer,!  are  always  found 

*  See  his  interesting  Memoir  in  the  Annales  des 
Sciences,  Nouv.  Scrie,  torn  i.  and  ii.,  1834. 

t  See  Bulletin  de  la  Socicte  Philomathique. 
Paris,  Avril,  1813. 


to  have  lost  it  entirely,  that  is,  the  femur,  tibia, 
and  tarsus,  are  all  wanting.  A  portion  of  a  leg  is 
never  found  detached  at  one  of  its  joints,  nor  bro- 
ken off  between  two  joints,  nor  the  femur  remuin- 
inj,  adherent  to  the  body  by  itself,or  with  the  tibia, 
the  rest  of  the  leg  being  lost.  If  by  accident  a 
spider  should  be  met  with  in  any  of  these  con- 
ditions, it  is  either  dying  or  dead.  But  M. 
Lepelletier  remarks  that  those  which  have  lost 
one  or  more  entire  legs,  are  not  less  lively  on 
that  account. 

To  explain  these  circumstances  our  author 
commenced  a  series  of  experiments  on  spiders, 
in  the  year  1792,  with  the  following  results: — 

The  smallest  wound  in  the  thorax  or  abdo- 
men of  a  spider  is  mortal,  and  that  in  a  very 
short  time,  on  account  of  the  loss  of  the  internal 
nutrient  fluid,  which  cannot  be  staunched. 

If  a  leg  of  a  spider  be  cut  off  with  a  sharp 
instrument  either  at  one  of  its  joints,  or  in  the 
interval  of  two,  leaving  a  part  of  the  limb  ad- 
hering to  the  body,  the  spider  appears  to  suffer 
considerably  ;  it  endeavours  to  tear  off  the  rest 
of  the  leg ;  if  it  succeeds,  it  again  acquires  its 
powers  of  moving,  and  the  hemorrhage  soon 
ceases ;  in  the  contrary  case  it  perishes  in 
twenty-four  hours. 

The  luxation  of  one  of  the  joints,  or  the  frac- 
ture of  the  femur  or  tibia  in  the  middle  are 
equally  mortal,  if  the  spider  does  not  soon  dis- 
embarrass itself  of  the  leg  which  has  received 
the  injury. 

It  is  necessary  here  to  make  a  remark  upon 
the  anatomy  of  the  legs  of  spiders  and  crusta- 
•  ceans ;  they  have  the  first  joint  short,  which 
connects  the  leg  to  the  thorax;  M.  Lepelletier 
calls  this  the  haunch,  coxa.  If  a  spider  be 
seized  by  the  extremity  of  one  of  its  legs,  and 
is  left  at  liberty  to  make  its  efforts  to  escape, 
the  leg  will  be  separated  from  the  body  at  the 
junction  of  the  femur  with  the  coxa  ;  and  the 
same  thing  takes  place  when  the  body  of  the 
spider  is  held  fast,  and  the  leg  is  pulled  off.  In 
both  these  cases  the  spider  seems  not  to  suffer 
pain  ;  it  experiences  only  a  very  little  loss  of  the 
internal  fluid,  and  does  not  die  in  consequence  ; 
it  spins,  seizes  its  prey,  and  oviposits  in  the  or- 
dinary manner. 

The  preceding  facts  are  applicable  to  all 
spiders,  (arane<e,)  and  M.  Lepelletier  has  ob- 
served them  repeatedly  in  many  of  the  common 
species.  The  following  experiments  have  been 
made  only  on  the  domestic  spider,  (Tegenaria 
domestica,  Walck.)  because  it  can  be  preserved 
in  a  lively  condition,  and  for  many  years  in  a 
glass  vessel. 

We  have  successively  observed  a  great  num- 
ber of  individuals  of  this  species  which  were 
mutilated  of  one  or  more  legs.  It  was  not 
without  surprize  that  the  author  of  this  article 
observed  the  first  spider  that  was  experimented 
upon,  and  which  wanted  a  leg,  change  its  skin, 
and  after  that  operation  reappear  with  eight 
legs.  The  like  occurrence  was  frequently  ob- 
served ;  the  new  leg  was  two  or  three  lines  in 
length  when  it  first  appeared,  that  of  the  oppo- 
site side  being  less  than  an  inch  :  each  of  the 
joints  of  the  former  continued  to  grow  during 
the  whole  of  the  year. 


216 


ARM. 


The  general  result  of  these  observations,  and 
of  many  others  of  the  same  kind,  is,  1st,  that 
the  legs  of  spiders  can  be  reproduced  when 
they  have  been  torn  off;  2d,  that  this  repro- 
duction can  only  take  place  when  the  limb  has 
been  detached  as  high  as  the  moveable  base ; 
for  otherwise  an  hemorrhage  supervenes  which 
kills  the  animal;  3d,  that  the  reproduction 
takes  place  only  at  the  time  of  the  moult,  and 
that  the  new  leg  is  at  hrst  slender,  but  with  all 
its  parts  or  joints,  each  of  which  increases  pro- 
gressively, until  the  whole  has  acquired  its 
natural  relative  size.* 

BIBLIOGRAPHY. — Lister  fy  Way,  Obs.  concerning 
the  darting  of  spiders,  Phil.  Trans.  1669  and  1670. 
Homberg,  Sur  les  araignees,  Mem.  de  Paris,  1707. 
Clerck,  V"om  fangen  und  Ernahren  der  Spinnen  Abh. 
d.  Schwed.  Akad.  J.  1761.  Boissier  de  Sauvages 
Obs.  sur  une  araigne,  Mem.  de  Paris,  1758.  Ha- 
gedorn,  De  Araneis,  Miscel.  Acad.  Nat.  cur.  Dec. 
II.  an  3,  1684.  Valentini,  Curiosa  in  araneis  ob- 
servata,  ib.  Dec.  ii.  an  7,  1688.  Dorthes,  Obs.  on 
the  structure  and  ceconomy  of  some  curious  species 
of  aranea  ;  Trans,  of  Linn.  Soc.  vol.  ii.  Paullini, 
De  aranea  rara,  Misc.  Ac.  Nat.  cur.  Dec.  iii.  an  3, 
1695.  Garmann,  Aranea  acre  nutrinntur  ib.  Dec.  i. 
an  1,  1670.  Wurmb,  Beschryving  van  te  groote 
tuin-spin  van  t'Eiland  Java;  Verhand.  v.  h.  Bataaf. 
Genoot.  Deel  3.  Latreille,  Sur  la  famille  des 
araignees  mineuses,  Soc.  Philomathique,  an  7. 
Prevost,  Sur  les  araignees  mineuses  :  Mem.  de  la 
Soc.  d'Hist.  Nat.  de  Paris,  Cah.  i.  Mariyn,  Aranei ; 
or,  a  natural  history  of  spiders,  4to.  Lond.  1793. 
JHahn,  Monographic  der  Spinnen,  4to.  Nurnb. 
1820-22.  Ej.  die  Arachniden  liv.  1—10.  Clerck, 
Aranei  Suecici,  4to.  Upsal.  1757.  Mueller,  Hydra- 
rachae  quas  in  aquis  Danije,  &c.  4to.  Lips.  1781. 
Lister,  Hist.  Animal.  Angliae,  4to.  Lond.  1678; 
Germanice  cum  add.  a  Martini  et  Goeze,  8vo. 
Quedlingb.  1778.  Meyer,  Ueber  ein.  Spinnen  d. 
Getting.  Gegend.  8vo.  Gotting.  1790.  Treviranus, 
Ueber  den  innern  Ban  der  Arachniden,  4to.  Nurn- 
berg,  1812.  Heroldt,  Exercit.  de  animal,  verteb. 
carent.  formatione  in  Ovo  Pars  prima :  De  genera- 
tione  aranearum,  fol.  Marb.  1824.  Wahkenaer, 
Faune  Parisienne,  2  torn.  8vo.  Paris,  1802  ;  Ej. 
Tableau  des  Araneides,  8vo'.  ih.  1805 ;  Ej.  Hist, 
des  Araneides,  Fasc.  5,  l2mo. ;  Ej.  et  de  Blainville, 
&c.  Araneides  de  France.  Lyonnet,  Rech.  sur 
Fanatomie  et  les  metamorphoses  de  differentes  es- 
peces  d'insectes,  4to.  Paris,  1832.  Roesel,  Insecten- 
Belustigungen,  4  torn.  4to.  Niirnberg,  1746. 

(Victor  Audouin.) 

ARM.  (Surgical  anatomy.)  (The  arm,  Gr. 
B^ot^uv.  Lat.  Brachium.  Fr.  Bras.  Germ. 
Oberarm.  Ital.  Braccio.)  The  ancients  ap- 
plied this  term  to  the  whole  of  the  upper 
or  thoracic  extremity  collectively,  as  most 
persons  do  in  ordinary  discourse,  at  the 
present  day ;  but  in  anatomical  language  the 
term  is  restricted  to  that  section  of  the  upper 
limb  included  between  the  shoulder  and  the 
elbow.  The  arm  taken  in  this  limited  sense 
is  somewhat  cylindrical,  a  little  flattened, 
however,  on  its  internal  and  external  surfaces, 
particularly  towards  its  middle  ;  it  varies 

*  Mr..Blackwall,  in  the  paper  already  referred  to, 
has  relatod  an  accidental  discovery  of  the  power  of 
some  spiders  to  abstract  respirable  air  from  water. 
Several  individuals  have  preserved  an  active  state 
of  existence  under  water  for  six,  fouiteen,  or  twenty- 
ei-jht  days,  spinning  their  lines  and  exercising  their 
functions  as  if  in  air,  while  others  have  not  sur- 
vived for  a  single  hour.  — ED. 


much  in  its  proportions  as  to  length  and 
volume :  it  is  more  rounded  in  fat  persons, 
and  especially  in  females,  in  whom  it  assumes 
more  or  less  of  a  conoid  form,  tapering  to- 
wards its  lower  part.  (See^g.  1  and  2,  p.  3.; 
The  arm  is  composed  of  a  single  bone,  the 
humerus,  several  muscles,  bloodvessels,  ab- 
sorbents, and  nerves  connected  together  by 
cellular  tissue,  and  inclosed  in  an  aponeurosis, 
which  lies  immediately  beneath  the  common 
integuments.  Viewing  the  arm  extended,  the 
hand  being  placed  in  a  state  of  supination, 
we  observe  at  its  superior  and  external  part 
a  prominence  of  a  triangular  form,  the  base 
of  which  is  superior;  this  is  formed  by  the 
deltoid  muscle,  and  is  bounded  before  and 
behind  by  two  slight  grooves,  which  unite 
below  in  a  depression  called  deltoid  fossa, 
situated  immediately  over  the  insertion  of  the 
deltoid  muscle;  this  deltoid  fossa  is  the  most 
eligible  part  of  the  arm  for  the  insertion  of 
issues,  as  it  contains  a  considerable  quantity 
of  cellular  tissue,  affording  a  favourable  bed 
for  the  reception  of  peas  or  other  bodies  in- 
serted for  the  purpose  of  exciting  suppuration, 
while  it  possesses  this  additional  advantage, 
that  no  muscular  fibres  extend  across  it,  whose 
contractions  might  have  the  effect  of  deranging 
the  surface  of  the  ulcer  or  the  dressings  neces- 
sary to  be  applied  to  it,  and  Jthus  causing  an 
unnecessary  degree  of  pain.  From  the  deltoid 
fossa  a  superficial  depression  extends  along  the 
outer  edge  of  the  arm,  and  terminates  in  the 
triangular  fossa  in  front  of  the  bend  of  the 
elbow:  along  the  course  of  this  depression 
blisters  are  frequently  applied  by  the  Parisian 
and  other  continental  physicians  in  inflam- 
matory affections  of  the  thoracic  viscera, 
a  mode  of  treatment  not  generally  employed 
in  such  cases  by  the  physicians  of  tin's 
country.  Another  depression  extends  along 
the  inner  side  of  the  arm  from  the  axilla  to 
the  hollow  in  front  of  the  elbow,  where  it  joins 
the  external  depression.  Between  these  two 
depressions  there  is  an  oblong  prominence  an- 
teriorly, formed  by  the  biceps  muscle,  and  a 
more  flattened  prominence  intervenes  poste- 
riorly, formed  by  the  triceps  which  occupies  the 
whole  of  the  posterior  surface  of  the  arm. 

Skin  and  subcutaneous  tissue.  —  The  skin 
covering  the  arm  is  soft  and  delicate;  sebaceous 
glands  and  hairs  are  not  very  evident  on  it, 
especially  in  front ;  it  is  thicker  and  stronger, 
however,  on  the  posterior  surface.  The  basilic 
vein  is  generally  visible  at  the  lower  part  of 
the  internal  brachial  depression,  and  the  pul- 
sations of  the  brachial  artery  may  be  felt  along 
the  whole  of  its  course:  the  cephalic  vein  is 
sometimes  visible,  especially  in  thin  persons, 
along  the  course  of  the  external  brachial  de- 
pression. As  the  skin  of  the  arm  is  loosely 
connected  to  the  subjacent  parts,  the  edges  of 
simple  incised  wounds  in  this  region  are  easily 
retained  in  contact.  The  subcutaneous  layer 
of  cellular  tissue  or  superficial  fascia  contains 
more  or  less  adipose  substance,  in  greater  abun- 
dance in  women  and  children  than  in  men, 
and  in  greater  quantity  in  the  depressions  than 
over  the  muscular  prominences ;  the  filaments 


ARM. 


217 


of  the  cutaneous  nerves  of  the  arm  and  the 
superficial  veins  and  absorbents  lie  imbedded 
in  it:  thus  the  cephalic  vein  and  twiu's  of  the 
external  cutaneous  nerve  appear  along  the 
outer  edge  of  the  arm,  and  along  the  inner 
edge  are  found  the  internal  cutaneous  nerve, 
the  braehial  branches  of  the  second  and  third 
intercostal  nerves,  the  cutaneous  nerve  which 
arises  from  the  ulnar  high  in  the  axilla,  the 
basilic  vein,  and  a  few  lymphatic  glands, 
which  lie  at  from  one  to  three  inches  above 
the  internal  condyle. 

Aponeurosis.  —  Beneath  the  subcutaneous 
layer  of  cellular  tissue  lies  the  aponeurosis  or 
fascia,  which  invests  the  muscles  and  the  deep- 
seated  vessels  and  nerves  of  the  arm  :  this 
fascia  commences  above  at  the  superior  attach- 
ment of  the  deltoid  muscle ;  externally  and 
internally  it  rs  cont.riuous  with  the  fascia, 
which  extends  over  the  axillary  space;  descend- 
ing along  the  arm  it  is  strengthened  by  ex- 
pansions which  it  receives  from  the  tendons 
of  the  deltoid,  pectoralis  major,  and  coraco- 
brachialis  in  front ;  and  behind  it  derives  an 
accession  of  strength  from  the  aponeurosis 
which  covers  the  infra-spinatus  and  teres  minor, 
and  from  the  tendons  of  the  latissimus  dorsi 
and  teres  major.  At  the  lower  part  of  the  arm 
the  fascia  is  attached  to  the  condyles  of  the 
humerus ;  laterally  and  posteriorly  it  is  at- 
tached to  the  olecranon,  on  either  side  of 
which  it  is  continuous  with  the  fascia  on  the 
posterior  surface  of  the  fore-arm.  In  front  of 
the  elbow  this  fascia  receives  a  fasciculus  of 
fibres  from  the  tendon  of  the  biceps,  and 
becomes  continuous  with  the  fascia  covering 
the  anterior  surface  of  the  fore-arm.  The 
fascia  of  the  arm  varies  in  strength  in  different 
parts ;  it  is  very  indistinct  over  the  deltoid, 
thin  but  very  fibrous  on  the  posterior  surface 
of  the  arm  where  it  covers  the  triceps ;  it  is 
much  stronger  over  the  biceps,  and  the  thickest 
portion  of  it  is  found  along  the  inner  edge  of  the 
arm,  where  it  covers  the  braehial  artery  and  its 
accompanying  veins  and  nerves.  A  strong 
aponeurotic  septum  passes  in  from  the  fascia 
of  the  arm  to  each  of  the  lateral  ridges  of  the 
humerus;  these  septa  are  called  intermuscular 
ligaments,  and,  together  with  the  humerus, 
divide  the  space  included  within  the  general 
fascia  into  an  anterior  and  a  posterior  sheath  ; 
the  external  intermuscular  ligament  extends 
from  the  insertion  of  the  deltoid  to  the  external 
condyle ;  the  internal  extends  from  the  inser- 
tion of  the  coraco-brachialis  to  the  internal 
condyle.  Both  intermuscular  ligaments  are 
narrowest  above,  and  grow  broader  as  they 
approach  the  condyles  :  their  surfaces  give  at- 
tachment to  fibres  of  the  triceps  posteriorly 
and  to  the  brachiacus  anticus,  supinator  radii 
longus,  and  extensor  carpi  radialis  anteriorly. 
The  posterior  sheath, formed  as  above  described, 
is  chiefly  occupied  by  the  triceps  muscle,  be- 
neath which,  in  the  spiral  groove  on  the  pos- 
terior surface  of  the  humerus,  lie  the  musculo- 
spiral  or  radial  nerve  and  the  superior  pro- 
funda  artery :  this  nerve  and  the  anterior  or 
musculo-spiral  branch  of  the  superior  pro- 
funda  artery  perforate  the  external  inter- 
muscular ligament  and  enter  the  anterior 


sheath  of  the  arm  to  get  between  the  brachiacus 
anticus  and  supinator  radii  longus,  while  the 
posterior  branch  of  the  profunda  descends 
within  the  posterior  sheath  to  the  back  part 
of  the  external  condyle ;  the  ulnar  nerve  and 
the  inferior  profunda  artery  enter  this  posterior 
sheath  together  at  its  internal  side,  about  the 
middle  of  the  arm,  and  descend  within  it  to 
the  back  of  the  internal  condyle.  A  considerable 
branch  of  the  braehial  artery,  the  ramus  anas- 
tomoticus,  perforates  the  internal  intermuscular 
ligament  above  the  internal  condyle,  and  enters 
the  lower  part  of  the  posterior  braehial  sheath. 
The  anterior  sheath  of  the  arm  contains  the 
biceps,  coraco-brachialis, brachiacus  anticus,  and 
the  origins  of  the  long  supinator  and  long 
radial  extensor  muscles;  the  external  cutane- 
ous nerve  traverses  this  sheath,  perforating  the 
coraco-brachialis  above,  and  descending  ob- 
liquely outwards  between  the  brachiaeus  anticus 
and  the  biceps  it  gets  to  the  outer  side  of  the 
latter,  between  the  tendon  of  which  and  the 
supinator  radii  longus  it  pursues  its  course  to 
the  fore-arm ;  the  radial  nerve  and  the  branch 
of  the  superior  profunda  artery  accompanying 
it  are  to  be  found  in  the  lower  and  external 
part  of  the  anterior  sheath,  which  they  enter 
as  above  described  :  these  lie  deep  between 
the  brachiaeus  anticus  and  supinator  longus. 
Along  the  internal  side  of  this  anterior  sheath, 
through  its  whole  extent,  run  the  braehial 
artery,  and  its  two  venae  comites  included  in  a 
sheath  proper  to  them,  and  accompanied  by 
the  median  nerve,  which  has  very  important 
relations  to  these  vessels  :  this  nerve  is  external 
to  the  artery  above,  crosses  it  in  the  middle 
of  the  arm,  and  lies  internal  to  it  below. 
Superiorly  the  ulnar  nerve  lies  to  the  inner 
side  of  the  braehial  artery,  from  which  it  se- 
parates to  enter  the  posterior  sheath,  as  already 
noticed ;  the  internal  cutaneous  nerve,  the 
cutaneous  twig  of  the  ulnar  nerve,  and  the 
basilic  vein  for  a  short  part  of  its  course 
before  it  enters  the  braehial  vein,  also  lie  within 
this  sheath ;  and  deeply  situated  in  its  lower 
part  is  the  ramus  anastomoticus  magnus  of  the 
braehial  artery. 

Developement. —  In  the  progressive  deve- 
lopement  of  the  upper  extremity  in  the  foetus, 
the  arm  is  formed  subsequently  to  the  hand 
•and  fore-arm,  and  at  an  earlier  period  than  the 
shoulder.  In  men  the  deltoid  is  fuller,  and  the 
biceps  in  front  and  the  triceps  behind  are  more 
prominent  than  in  women :  the  greater  fulness 
of  these  two  latter  muscles,  with  the  smaller 
quantity  of  subcutaneous  fat,  give  to  the  male 
arm  a  greater  diameter  from  before  backwards 
than  in  the  transverse  direction ;  while  the 
more  slender  character  of  the  muscles  and  the 
greater  abundance  of  subcutaneous  fat  laterally 
cause  the  arm  of  the  female  to  assume  a  more 
rounded  form.  In  the  course  of  the  braehial 
artery  two  trunks  are  often  found  to  exist,  in 
consequence  of  a  high  branching  of  that  vessel, 
which  sometimes  occurs  even  at  the  lower 
border  of  the  axilla:  the  supernumerary  branch 
in  such  cases  is  most  frequently  the  radial : 
in  some  instances  it  is  the  ulnar  and  less  fre- 
quently the  interosseous  or  median  artery  of 
the  fore-arra:  When  this  irregularity  occurs,  the 


218 


ARM. 


brachial  artery  usually  preserves  its  ordinary 
relations  to  the  surrounding  parts,  while  the 
supernumerary  trunk  lies  to  its  internal  side 
and  takes  a  more  superficial  course,  some- 
times getting  above  the  fascia  of  the  arm,  as 
we  have  witnessed  in  a  few  rare  cases.  It 
occasionally  happens  that  the  brachial  artery 
divides  at  its  commencement  into  two  trunks, 
which  again  unite  at  its  lower  part.  It  is  ob- 
vious that  the  surgeon,  in  performing  operations 
on  this  artery,  should  constantly  bear  in  mind 
that  it  is  subject  to  the  above-mentioned  irre- 
gularities, and  that  he  should  cautiously  guard 
against  committing  the  error  of  including  the 
wrong  vessel  in  his  ligature. 

The  internal  side  of  the  arm  in  the  middle 
of  its  length  is  the  most  eligible  place  for 
making  compression  on  the  brachial  artery; 
here  this  vessel  is  superficial,  so  that  its  pul- 
sation can  be  felt  at  once,  whilst  it  has  nothing 
interposed  between  it  and  the  bone  but  the 
tendinous  insertion  of  the  coraco-brachialis 
muscle.  It  happens,  however,  that  the  median 
nerve  lies  immediately  over  the  artery  in  this 
situation,  a  circumstance  which  causes  com- 
pression of  the  latter  to  be  attended  with  con- 
siderable pain,  and  productive  of  injury  to  the 
nerve  if  maintained  for  too  great  a  length  of  time. 

As  the  trunk  of  the  brachial  artery  and 
several  large  nerves  traverse  this  part  of  the 
arm,  it  is  obvious  that  wounds  in  this  region 
are  liable  to  be  attended  with  more  serious 
consequences  than  those  of  any  other  part  of 
the  arm.  A  wound  in  the  posterior  region  of 
the  arm  may  be  attended  with  considerable 
haemorrhage,  if  it  should  happen  to  penetrate  so 
deep  as  to  divide  the  profunda  artery,  or  it  may 
cause  paralysis  of  the  extensor  muscles  of  the 
hand  and  fingers  by  dividing  the  radial  nerve. 

When  the  humerus  is  fractured,  the  con- 
sequent derangement  of  the  fragments  varies 
according  to  the  part  at  which  the  bone  hap- 
pens to  be  broken  ;  when  fracture  occurs  im- 
mediately above  the  insertions  of  the  pectoralis 
major  and  latissimus  dorsi,  the  lower  fragment 
is  brought  inward  towards  the  axilla  by  the 
action  of  these  muscles,  and  drawn  upwards 
by  the  action  of  the  deltoid,  biceps,  coraco- 
brachialis,  and  long  head  of  the  triceps,  whilst 
the  extremity  of  the  upper  fragment  is  rather 
turned  outwards  by  the  supra-spinatus.  In 
cases  where  the  humerus  is  fractured  imme- 
diately above  the  insertion  of  the  deltoid  and 
below  the  attachments  of  the  latissimus  dorsi 
and  pectoralis  tnajor,  the  deltoid  will  draw  the 
lower  fragment  upwards  and  outwards,  whilst 
the  upper  fragment  will  be  drawn  inwards 
towards  the  axilla  by  the  pectoralis  major  and 
latissimus  dorsi.  If  the  bone  be  broken  im- 
mediately below  the  insertion  of  the  deltoid, 
little  or  no  displacement  of  the  fragments  may 
ensue,  as  the  opposing  forces  exercised  on  the 
superior  fragment  by  the  deltoid  on  the  ex- 
ternal side,  and  the  pectoralis  major  and  latis- 
simus dorsi  on  the  internal,  pretty  nearly 
counterbalance  each  other;  it  more  generally 
happens,  however,  that  the  upper  fragment  is 
turned  outwards  by  the  preponderating  action 
of  the  deltoid  upon  it,  whilst  the  lower  frag- 
ment is  drawn  upwards  by  the  action  of  the 


biceps,  coraco-brachialis,  and  triceps.  Frac- 
tures of  that  portion  of  the  humerus  which  is 
covered  by  the  brachiseus  anticus  in  front  and 
the  triceps  behind,  are  often  unattended  by 
any  very  obvious  displacement,  in  consequence 
of  these  muscles  being  inserted  into  both  frag- 
ments ;  fractures  near  the  elbow  are  occa- 
sionally followed  by  deformities  presenting 
some  of  the  characters  of  dislocations  of  the 
elbow,  of  which  more  notice  will  be  taken  in 
the  article  ELBOW. 

General  inflammatory  enlargement  of  the 
arm  is  rare ;  it  sometimes  appears  as  a  con- 
comitant affection  with  inflammation  of  the 
veins  of  the  arm  consequent  on  the  operation 
of  phlebotomy,  in  which  case  it  not  unfre- 
quently  happens  that  abscesses  form  along  the 
course  of  the  sheath  of  the  brachial  artery ; 
red  streaks  along  the  course  of  the  lymphatics 
and  enlargement  of  the  lymphatic  glands  are 
sometimes  present  in  consequence  of  disease 
or  inflammation  affecting  the  hand  or  fore-arm. 

Amputation  of  the  arm  below  the  insertion 
of  the  deltoid  may  be  performed  either  by  the 
circular  incision  or  the  double  flap ;  when  the 
latter  method  is  practised,  the  flaps  should  be 
formed  on  the  external  and  internal  sides,  by 
which  the  more  important  vessels  and  nerves 
will  be  included  in  the  internal  flap. 

When  circumstances  require  the  performance 
of  amputation  above  the  insertion  of  the  del- 
toid, the  circular  operation  should  never  be 
practised,  for  the  following  reason ; — in  order 
to  obtain  a  sufficiency  of  covering  for  the  bone, 
the  pectoralis  major,  latissimus  dorsi,  and  tores 
major  would  all  be  detached  from  their  inser- 
tions, a  consequence  of  which  would  be  that  the 
contractions  of  these  muscles  in  opposite  di- 
rections, by  drawing  asunder  the  edges  of  the 
wound,  would  not  only  render  complete  appo- 
sition difficult  in  the  first  instance,  but  more- 
over their  continued  action  would  have  the 
effect  of  converting  the  wound  into  an  ulcer, 
which  it  would  be  extremely  difficult  if  not 
impossible  to  heal ;  therefore,  whenever  we 
have  to  amputate  so  high  up,  it  is  the  more 
judicious  mode  of  proceeding  to  make  a  flap 
including  so  much  of  the  deltoid  muscle  as 
will  form  a  sufficient  covering  for  the  stump. 
The  importance  of  attending  to  the  foregoing 
circumstances  was  first  pointed  out  by  Louis, 
the  learned  secretary  to  the  French  Academy 
of  Surgery.* 

The  arteries  which  require  to  be  tied  after 
amputation  of  the  arm  below  the  insertion  of 
the  deltoid  are  the  brachial  and  inferior  pro- 
funda on  the  internal  side ;  on  the  external  side 
there  are  often  two  branches  of  the  superior 
profunda  requiring  a  ligature,  one  of  which 
accompanies  the  musculo-spiral  nerve,  and  the 
other  runs  in  the  substance  of  the  triceps. 

When  it  becomes  necessary  to  tie  the  bra- 
chial artery  on  account  of  a  wound  or  aneu- 
rism, the  varieties  of  its  relation  to  the  median 
nerve  should  be  carefully  borne  in  mind;  at 
the  upper  part  of  the  arm  this  artery  has  the 
median  nerve  external  to  it,  and  the  ulnar 
nerve  to  its  inner  side ;  in  the  middle  of  the 

*  Memoires  de  TAcadcmie  de  Chirurgic,  torn.  v. 


ARM,  MUSCLES  OF  THE. 


arm  the  median  nerve  crosses  the  artery  in 
general  superficial  to  it,  but  sometimes  under- 
neath it,  while  in  the  lower  part  of  the  arm  this 
nerve  is  invariably  on  its  inner  side. 

When  called  upon  to  expose  the  brachial 
artery  for  the  purpose  of  tying  it,  the  surgeon 
should  recollect  that  the  course  of  the  artery 
may  be  readily  determined  by  a  line  drawn 
from  the  coracoid  process  to  a  point  midway 
between  the  condyles  of  the  humerus  on  the 
anterior  surface  of  the  elbow ;  hence  his  in- 
cision for  the  purpose  of  exposing  the  brachial 
artery  should  be  always  made  along  the  course 
of  this  line  and  perpendicular  to  the  axis  of 
the  os  humeri.  (See  BRACHIAL  ARTERY.) 

For  BIBLIOGRAPHY,  see  ANATOMY  (INTRO- 
DUCTION.) 

(John  Hart.) 

ARM,  MUSCLES  OF  THE.— The  mus- 
cles which  clothe  the  os  humeri  are  part  of  the 
deltoid,  the  biceps,  coraco-brachialis,  brach'ueus 
anticus,  the  origin  of  the  suplnutor  longus  in 
front,  and  the  triceps  behind. 

The  deltoid  belongs  to  the  shoulder,  and 
will  be  described  with  the  other  muscles  of 
that  part.  (See  SCAPULAR  REGION.) 

1.  Coraco-brachialis  (coraco-humeral). — 
The    coraco-brachialis   arises   from   the   point 
of  the  coracoid  process,  in  common  with   the 
short  head  of  the  biceps,  tendinous  in  front  and 
fleshy  behind ;  it  separates  from  the  biceps  at 
its  middle  third,  passes  inwards,  and   is  in- 
serted tendinous  into  the  internal  surface  of  the 
\humerus  a  little  above  its  middle  between  the 
triceps  and  brachiaeus  anticus. 

This  muscle  has  in  front  of  it  the  deltoid 
and  pectoralis  major,  which  cover  and  conceal 
from  view  its  upper  part;  behind  it  the  tendon 
of  the  subscapularis,  the  tendons  of  the  latissi- 
mus  dorsi  and  teres  major,  the  axillary  artery, 
the  median  and  the  external  cutaneous  nerves. 
The  latter  nerve  perforates  the  muscle  about 
its  middle,  and  passes  through  its  substance 
to  reach  the  outer  side  of  the  arm  ;  hence  the 
epithet  pcrforatus  has  been  applied  to  this 
muscle.  The  coraco-brachialis  can  carry  the 
arm  forwards  and  inwards ;  when  the  humerus 
is  fixed,  it  can  act  upon  the  scapula,  and  by 
depressing  its  coracoid  angle,  elevate  the  in- 
ferior angle  and  separate  it  from  the  ribs. 

2.  Biceps  jlexor  cubiti  (scapulo-coraco-ra- 
diul). — This  is  a  long  muscle  swollen  in  the 
centre,  divided  above  into  two  portions  called 

&*  heads,  one  internal  short,  the  other  external 
long.  The  internal  or  short  head  arises  from 
the  coracoid  process  of  the  scapula  in  common 
with  the  coraco-brachialis.  The  long  head  is 
attached  by  a  long  slender  flattened  tendon  to 
the  upper  part  of  the  margin  of  the  glenoid 
cavity,  and  is  united  by  a  dense  cellular  tissue 
to  the  glenoid  ligament.  This  tendon  passes 
over  the  head  of  the  humerus,  and  enters 
the  groove  between  the  two  tuberosities  in 
which  it  is  bound  down  by  the  fibres  of  the 
capsular  ligament  of  the  shoulder-joint ;  a  pro- 
longation of  the  synovial  membrane  also  lines 
the  groove,  and  forms  a  synovial  sheath  for 
the  tendon  ;  the  tendon  terminates  in  a  fleshy 
belly  which  unites  with  the  short  head  to  form 


tjje  large  belly  of  the  biceps ;  the  muscle  ter 
initiates  below  in  a  tendon,  which,  passing 
over  the  brachiaeus  anticus  and  the  front 
of  the  elbow-joint,  sinks  into  a  triangular 
hollow  between  the  pronator  teres  and  supina- 
tor  longus  to  be  inserted  into  the  back  part 
of  the  tubercle  of  the  radius ;  but  before  it  sinks 
into  this  triangular  space,  it  sends  off  from  its 
internal  side  an  aponeurosis  (the  sewilunar 
fascia  of  the  biceps),  which  is  inserted  into  the 
internal  condyle,  and  the  fascia  which  covers  the 
muscle  at  the  inner  side  of  the  bend  of  the  elbow. 
The  biceps  is  covered  by  the  deltoid,  the 
pectoralis  major,  the  fascia  of  the  arm  and 
integuments  in  front ;  behind  it  lies  on  the 
humerus,  coraco-brachialis,  brachiaeus  anticus, 
and  the  external  cutaneous  nerve ;  internal  to 
it  lie  the  coraco-brachialis  and  brachial  artery. 
It  bends  the  elbow  and  makes  tense  the  fascia 
of  the  fore-arm ;  it  is  also  a  very  powerful 
supinator  of  the  hand  by  virtue  of  its  insertion 
into  the  radius.  If  the  fore-arm  be  extended  and 
fixed,  it  will  depress  the  scapula  on  the  humerus. 

3.  Brachuuti  anticus  (  B.  internus,  hume- 
rocubital). — When  the  biceps  has  been  raised 
from  its   situation,  we   observe  the  brachiaeus 
anticus  deeply  situated  on  the  front  of  the  arm  ; 
it  arises  by  two  fleshy  tongues,   one  on  each 
side  of  the  insertion  of  the  deltoid ;   from  the 
whole  of  the  anterior  surface  of  the  humerus, 
and  the  internal  intermuscular  ligament  which 
separates  it  from  the  triceps,   its  fleshy  fibres 
pass  downwards  in  front  of  the  elbow,  and 
end  in  a  broad  tendon  which  is  inserted  into  a 
triangular  roughness   on  the  anterior   surface 
of  the  coronoid   process  of  the  ulna.     This 
muscle  is  covered  in  front  by  the  biceps,  supi- 
nator longus,  the  fascia  of  the  arm  and  integu- 
ments,   the    musculo-cutaneous    and    median 
nerves,  the  brachial  artery,  and  the  pronator 
teres ;  behind  it  covers  the  front  of  the  lower 
part  of  the  humerus  and  the  elbow-joint.   This 
muscle  is  the  most  powerful  flexor  of  the  fore- 
arm upon  the  arm.    As  Bichat  remarks,  flexion 
of  the  fore-arm  takes  place  directly  if  the  bra- 
chiaeus combines  its  action  with  that  of  the 
biceps ;  if  either  acts  alone,  the  flexion  is  in  the 
direction  inwards  oroutwards;  inwards  when  the 
biceps  acts  alone,  outwards  when  the  brachiaeus. 

4.  Triceps  extensor  cubiti  (brachiaus  posti- 
cus,   tri-scapulo-humero-olecranien,) — The  tri- 
ceps muscle  of  the  arm  is  situated  on  the  poste- 
rior surface  of  the  humerus,  and,  as  its  name 
implies,  has  its  origin  by  three  heads.  The  long 
head  arises  by  a  short,  flat,  thick  tendon  from 
a  rough  portion  of  the   inferior  costa  of  the 
scapula,  immediately  below  the  glenoid  cavity, 
and  passing  downwards  in  front  of  the  inser- 
tion of  the  teres  minor,  and  behind  the  teres 
major  it  forms  a  large  belly,  which  covers  the 
posterior  surface  of  the  os  humeri.     The  se- 
cond or  short  head  arises  from  the  outer  and 
back  part  of  the  os  humeri,  beginning  by  a 
pointed  origin  immediately  below  the  insertion 
of  the  teres  minor ;  it  continues  to  arise  from 
the  external  ridge  of  the  humerus  as  low  down 
as  the  external  condyle;  from  the  surface  of 
the  bone  behind  this  ridge,  and  from  the  back 
part  of  the  external  intermuscular  ligament. 
The  third  head,  which  is  the  shortest,  called 


220 


ARTERY. 


brachi&us  externus,  arises  by  an  acute  point 
from  the  internal  ridge  of  the  os  humeri,  be- 
ginning immediately  below  the  insertion  of 
the  teres  major;  it  also  arises  from  the  internal 
ridge  as  far  down  as  the  internal  condyle,  from 
the  surface  of  the  humerus  behind  this  ridge, 
and  from  the  posterior  surface  of  the  internal  in- 
termuscular  ligament.  The  three  heads  unite 
above  the  middle  of  the  os  humeri,  and  cover  the 
whole  of  the  back  part  of  that  bone ;  they  form 
a  thick  broad  tendon,  which  is  inserted  into 
the  rough  surface  on  the  superior  part  of  the 
olecranon  process  of  the  ulna,  adhering  closely 
to  the  ligamentous  fibres  covering  the  posterior 
surface  of  the  synovial  membrane  of  the 
elbow-joint ;  the  lowest  fibres  of  the  second 
and  third  heads  of  this  muscle,  which  arise 
from  the  back  of  the  condyles,  run  nearly 
horizontally  into  the  tendon. 

The  triceps  is  covered  posteriorly  by  the 
teres  minor,  deltoid,  fascia  of  the  arm  and  in- 
teguments ;  in  front  it  is  in  contact  with  the 
posterior  surface  of  the  humerus,  the  inter- 
muscular  ligaments,  and  the  back  part  of  the 
capsule  of  the  elbow-joint.  This  muscle  ex- 
tends the  elbow ;  when  the  long  head  contracts, 
it  draws  the  scapula  towards  the  humerus, 
and,  if  the  scapula  be  fixed,  it  draws  the 
humerus  backwards. 

For  BIBLIOGRAPHY,  see  MUSCLE,  and  ANATOMY 
(INTRODUCTION). 

(J.  Hart.) 

ARTERY,  (normal anatomy):  a£T»?£ia,  ano 
Toy  TOK  aepa,  TVJPSIV,  ab  aere  servando.  1'r.  ar- 
tere.  Germ.  Pulsader,  Schlagader.  Ital.  arteria. 
The  arteries  are  the  vessels  which  carry  the 
blood  from  the  heart,  and  distribute  that  fluid 
throughout  the  body.  The  trachea  was  ori- 
ginally called  artery  from  the  circumstance  of 
its  containing  the  air  which  it  transmits  to  the 
lungs.  The  term  artery  was  exclusively  ap- 
plied to  the  trachea  by  Hippocrates  and  his 
cotemporaries,  by  whom  the  vessels  now  called 
arteries  were  described  as  pulsating  veins. 
Aristotle  restricted  the  term  artery  to  the  tra- 
chea, and  described  the  aorta  as  the  lesser 
vein.  We  find  these  vessels  called  arteries 
in  the  writings  of  Aretaus,  Pliny,  and  Hero- 
philus,  probably  on  account  of  the  adoption  of 
the  opinion  of  Erasistratus,  who  taught  that  they 
contained  a  vapour  or  spirit.  The  vessels  now 
known  as  arteries,  however,  were  more  dis- 
tinctly so  designated  by  Galen,  who  affirmed 
that  they  were  full  of  blood,  and  described  the 
arteries  and  veins  as  forming  each  a  tree,  whose 
roots  implanted  in  the  lungs,  and  whose 
branches  distributed  through  the  body,  were 
united  by  a  common  trunk  in  the  heart. 

There  are  two  great  arterial  trunks — the 
aorta,  which  arises  from  the  left  ventricle  of 
the  heart,  and  the  pulmonary  artery,  which 
arises  from  the  right  ventricle  of  that  organ. 
Each  of  these  vessels  has  an  origin,  a  trunk, 
and  branches,  which  divide  and  subdivide  in 
an  arborescent  form,  until  they  are  reduced  in 
size  to  the  most  delicate  degree  of  minuteness, 
terminating  in  the  capillary  vessels,  which  can 
be  traced  entering  into  all  structures  except 
cartilage,  hairs,  and  epidermoid  parts.  Striking 


as  the  contrast  is  between  the  size  of  the  primi- 
tive arterial  trunks  and  that  of  the  almost  in- 
visible capillary  vessels,  comparatively  few 
divisions  intervene  between  the  two  extremes 
of  the  arterial  system,  their  number  hardly 
exceeding  twenty,  as  Haller  ascertained  by 
counting  the  divisions  of  the  arteries  of  the 
mesentery  between  the  place  of  their  origins 
from  the  aorta,  and  their  termination  in  the 
capillaries  of  the  intestines.* 

That  the  arteries  in  general  are  circular 
tubes  is  evident  from  an  inspection  of  their 
orifices  when  cut  across,  even  in  the  dead 
body.  The  walls  of  the  larger  arteries,  when 
empty,  collapse,  so  as  to  present,  on  a  trans- 
verse section,  an  aperture  more  or  less  ellipti- 
cal:  when  distended,  however,  either  by  the 
blood  during  life,  or  by  injection  in  the  dead 
body,  these  also  are  circular ;  so  that  the 
circular  form  may  be  considered  as  universal 
in  all  parts  of  the  animal  system  except  at  the 
origins  of  the  aorta  and  pulmonary  artery, 
where  the  circumference  of  each  of  these  ves- 
sels is  distended  into  three  sacculated  pouches 
of  equal  size,  called  the  lesser  sinuses ;  and  in 
the  ascending  portion  of  the  arch  of  the  aorta, 
which  has  a  dilatation  on  its  right  side,  in- 
creasing with  years,  called  the  greater  sinus. 

The  arteries  in  general  become  smaller  in 
their  course  in  proportion  to  the  number  of 
branches  arising  from  them.  To  this,  however, 
there  are  exceptions,  of  which  the  aorta  pre- 
sents a  remarkable  example,  being  of  as  great 
a  capacity  near  the  origins  of  the  primitive  iliac 
arteries  as  it  is  in  its  thoracic  portion,  and  the 
vertebral  arteries  are  as  large  where  they  enter 
the  foramen  magnum  of  the  occipital  bone  as 
where  they  arise  from  the  trunks  of  the  sub- 
clavians,  notwithstanding  that  they  have  given 
off  many  branches  in  the  intermediate  part  of 
their  course. 

Wherever  an  artery  runs  for  some  distance 
without  giving  off  branches,  it  appears  to  suffer 
no  perceptible  diminution  in  its  size,  as  has 
been  ascertained  by  the  experiments  referred  to 
by  Baron  Haller,!  and  repeated  by  Mr.  Hunter,}: 
in  which  the  common  carotids  were  found  as 
capacious  near  the  place  of  their  division  into 
the  external  and  internal  carotids  as  at  their 
origins ;  and  the  same  remark  being  considered 
as  equally  applicable  to  all  other  arteries  simi- 
larly circumstanced,  it  has  been  stated  in 
general  terms  that  the  arteries  and  their  branches 
are  cylindrical,  and  that  the  whole  of  the 
arterial  system  is  a  series  of  cylindrical  tubes. 

Although  the  cylindrical  form  is  pretty 
general  throughout  the  arterial  system,  it  is  by 
no  means  accurately  preserved.  Several  arteries 
increase  in  size  in  the  progress  of  their  course ; 
of  this  we  have  examples  in  the  umbilical 
arteries,  which  expand  as  they  approach  the 
placenta,  and  the  spermatic  arteries,  especially 
in  the  bull  and  wild  boar,  which  enlarge  con- 
siderably as  they  proceed  to  their  destination. 
Moreover,  Haller  §  and  Martinus  have  shown 


*  Haller,  Elementa  Physiologiae,  t.  i.  sect.  1.  $  17. 
t  Elementa  Physiologiae,  t.  i.  s.  1,  §  3. 
$  Treatise   on   the    Blood,  &c.,   p.   168  et  seq. 
4to  edit.  Lond.  1794. 

§  Elementa,  t,  i.  s.  3,  $  3. 


ARTERY. 


221 


by  experiments,  that  in  every  instance  where  an 
artery  divides  in  the  human  body,  it  undergoes 
a  dilatation  immediately  before  such  division; 
and  this  (act  derives  confirmation  from  the 
experiments  of  Mr.  Hunter  on  the  carotid  arte- 
ries :  it  is  much  more  unusual  for  an  artery  to 
diminish  in  size  in  its  course  unless  it  has 
furnished  branches.  Santorini*  states,  how- 
ever, that  he  observed  the  carotid  artery  of  an 
ostrich  (Struthio  camelus)  to  have  become  nar- 
ro.ver  in  a  portion  of  its  course  of  six  inches  in 
length,  for  which  space  no  branch  had  been 
given  off. 

The  arteries  become  smaller  and  more  nu- 
merous by  repeated  divisions :  the  combined 
area  of  the  branches  of  each  artery,  however, 
exceeds  the  area  of  the  trunk  from  which  they 
are  given  off,  in  every  instance,  in  consequence 
of  which  the  capacity  of  the  arterial  system,  as 
a  whole,  is  increased  in  proportion  to  the 
number  of  its  divisions.  It  is  from  this  cir- 
cumstance that  the  arteries  have  been  said  to 
represent  a  cone,  the  apex  of  which  is  at  the 
heart,  and  the  base  in  the  capillaries. 

When  an  artery  divides  into  several  branches 
of  unequal  size,  the  largest  usually  continues 
its  course  in  the  direction  of  the  original  trunk. 

The  branches  of  the  arteries  are  for  the  most 
part  given  off  at  acute  angles ;  some  few,  as 
the  superior  aortic  intercostals,  go  off  at  obtuse 
angles,  and  the  lumbar  arteries  arise  from  the 
aorta  at  right  angles. 

The  arteries  appear  in  general  to  take  the 
shortest  course  to  the  parts  they  supply  ;  hence 
the  tendency  they  have  to  run  in  straight  lines. 

In  many  situations  the  arteries  are  remark- 
able for  having  a  tortuous  course,  as  is  par- 
ticularly evident  in  the  arteries  of  the  stomach, 
intestines,  bladder,  uterus,  lips,  iris,  &c.,  where 
this  disposition  appears  to  be  a  provision  to 
obviate  any  interruption  to  the  circulation 
which  might  result  from  the  great  or  sudden 
changes  of  volume,  form,  or  situation  to  which 
those  organs  are  subject  in  the  performance  of 
their  functions :  in  other  instances  the  arteries 
appear  to  be  contorted  for  the  purpose  of 
breaking  the  impulse  of  the  systole  of  the  ven- 
tricle on  the  blood,  and  thereby  moderating  the 
force  with  which  that  fluid  is  propelled  into 
vessels  partaking  of  the  delicacy  of  structure 
of  certain  organs  to  which  they  are  distributed, 
as  the  arteries  of  the  brain,  spleen,  testicle,  &c. 

The  smaller  arteries,  running  among  loose 
structures,  are  rendered  tortuous  during  each 
systole  of  the  ventricle  of  the  heart,  a  pheno- 
menon which  we  have  frequently  witnessed 
where  such  vessels  were  exposed  for  a  few 
inches  of  their  course  during  surgical  operations. 

Anastomoses. — The  several  parts  of  the  arte- 
rial system  communicate  freely  with  each  other; 
and  these  communications,  known  by  the  name 
of  anastomoses,t  are  more  frequent  between  the 
arteries  in  proportion  to  the  remoteness  of  these 
vessels  from  the  heart.  Three  kinds  of  anas- 
tomosis have  been  distinguished  by  anatomists : 
first,  two  vessels  of  nearly  equal  size  approach 
and  join  so  as  to  form  an  arch  in  such  a  man- 

*  Observationes  Anatom.  c.  7.  n.  6. 
t  From  ava,  per,  no  pa.,  os. 


ner  as  to  render  it  impossible  to  determine  the 
exact  point  of  their  union  :  this  arch  gives  off 
smaller  vessels.  Of  this  kind  is  the  anasto- 
mosis which  takes  place  between  the  arteries  of 
the  intestines  and  the  arteries  in  the  neigh- 
bourhood of  joints.  Secondly,  two  arteries  are 
sometimes  connected  by  a  transverse  branch, 
as  the  two  anterior  cerebral  in  the  arterial  circle 
at  the  base  of  the  brain.  We  find  this  kind  of 
communication,  also,  between  the  two  um- 
bilical arteries  as  they  approach  the  placenta. 
Thirdly,  two  arteries  join  at  an  acute  angle,  so 
as  to  form  a  single  trunk  :  thus  the  two  verte- 
bral arteries  form  the  basilar,  the  two  anterior 
arteries  of  the  spinal  cord  unite  in  a  single 
trunk  ;  and  in  the  foetus  the  ductus  arteriosus 
joins  the  thoracic  aorta  in  a  similar  manner. 
Besides  these  more  obvious  communications 
between  vessels  of  a  larger  size,  the  anastomoses 
of  the  capillaries  are  so  frequent  as  to  give  to 
those  vessels,  when  successfully  injected,  the 
appearance  of  a  fine  net-work. 

It  is  by  means  of  the  anastomoses  that 
the  circulation  is  carried  on  in  a  limb  after  the 
trunk  of  its  chief  artery  has  been  obliterated 
by  disease,  injury,  or  a  surgical  operation ;  and 
the  well-known  efficiency  of  the  anastomosis  of 
arteries  in  re-establishing  the  circulation  in 
parts  from  which  the  direct  supply  of  blood 
through  the  principal  artery  has  been  cut  off', 
has  led  to  the  performance  of  some  of  the  most 
brilliant  operations  by  which  modern  surgery 
has  been  raised  to  the  exalted  rank  it  holds  at 
the  present  day. 

The  larger  trunks  of  arteries  are  inclosed 
within  the  cavities  of  the  body,  or  run  their 
course  on  the  sides  of  the  limbs  least  exposed 
to  external  injuries,  being  in  general  deeply 
situated  in  the  intervals  between  the  muscles, 
so  as  to  be  protected  against  wounds  or  other 
external  injuries,  to  which  they  are  therefore 
less  exposed  than  if  they  had  been  more  super- 
ficially situated. 

The  arteries  and  their  branches  are  every 
where  surrounded  by  a  layer  of  cellular  tissue, 
called  the  arterial  she.ith,  connected  more  or 
less  intimately  with  the  neighbouring  struc- 
tures, but  having  so  loose  an  attachment  to  the 
arteries  as  to  allow  them  to  glide  freely  on  its 
inner  surface  in  all  their  motions,  by  which 
means  they  frequently  escape  being  injured 
when  penetrating  wounds  traverse  parts  con- 
tiguous to  them  ;  and  it  is  owing  to  the  loose- 
ness of  the  attachment  of  the  arteries  to  their 
sheath  that  they  retract  so  remarkably  within  it 
when  cut  across.  The  sheath  is  generally 
strongest  around  the  arteries  most  exposed  to 
external  injury :  thus  it  is  particularly  strong 
where  it  surrounds  the  arteries  of  the  limbs;  it 
is  less  distinct  on  the  arteries  within  the  thorax 
and  abdomen,  many  of  which  receive  coverings 
from  the  serous  membranes;  and  it  is  so  ex- 
tremely delicate  around  the  arteries  of  the 
encephalon  as  to  have  its  existence  in  this 
situation  questioned  by  some  anatomists. 

Structure  of  arteries. — The  arteries  are  of  a 
pale  buff  colour  when  empty.  The  absolute 
thickness  of  their  parietes  is  greatest  in  the 
larger  trunks,  but  more  considerable  in  pro- 
portion to  their  calibre  in  the  smaller  branches. 


222 


ARTERY. 


The  parietes  of  arteries  are  divisible  into  three 
tunics,  known  by  the  names  of  "external,  mid- 
dle, and  internal. 

The  external  tunic,  called  the  cellular  coat, 
(tunica  cellulosa  propria  of  Haller,)  is  of  a 
whitish  colour,  thin,  dense,  and  firm  :  it  is 
formed  of  condensed  cellular  tissue,  containing 
fibres  closely  interwoven  and  crossing  each 
other  at  obtuse  angles  to  the  length  of  the 
vessels.  The  structure  of  this  tunic  is  loose 
on  its  external  surface,  and  connected  by  deli- 
cate laminae  with  the  arterial  sheath  :  its  internal 
surface  is  very  closely  attached  to  the  external 
surface  of  the  middle  tunic. 

The  middle  tunic  of  the  arteries  (the  tunica 
musculosa  of  Haller)  is  dense,  firm,  of  a  red- 
dish yellow  colour,  and  composed  of  fibres, 
which,  on  a  superficial  view,  seem  to  run 
transversely :  when  this  tunic  is  submitted  to 
a  closer  examination,  we  find  that  none  of  its 
fibres  are  sufficiently  long  to  form  perfect  rings 
encircling  the  whole  of  the  circumference  of 
the  vessels;  they  are  all  short  and  straight, 
with  a  slight  degree  of  obliquity  in  their  direc- 
tion, and  their  extremities  are  lost  among  the 
neighbouring  fibres.  The  middle  tunic  may 
be  divided  into  several  layers  by  the  knife  of 
the  anatomist,  and  these  are  found  to  increase 
in  density  from  the  external  to  the  internal 
surface.  There  are  no  longitudinal  fibres  in 
this  structure. 

As  Haller  has  remarked,  the  middle  tunic 
of  the  arteries  is  not  continuous  with  the  mus- 
cular substance  of  the  heart.     For  the  descrip- 
tion of  the  manner  in  which  the  middle  tunic 
of  the  arteries  is  connected  with  the  heart,  and 
of  the  fibrous  structure    interposed  between 
the  muscular  texture  of  that  organ  and   the 
middle  tunic  of  the  arteries,  we  refer  to  the 
article  AORTA.    The  continuity  of  the  middle 
tunic  through  all  parts  of  the  arterial  system 
is  uninterrupted.    Although  the  absolute  thick- 
ness of  this  tunic  is  greatest  in  the  aorta  and 
larger  trunks,  its  thickness  in  proportion  to 
the  area  of  the  vessels  manifestly  increases  as 
these  diminish  in  size ;  wherever  an  artery  is 
curved,  it  is  thicker  on  the  convex  than  on  the 
concave  side,  and  in  all  the  angles  formed  by 
the  divisions  of  arteries  its  thickness  is  more 
considerable  than   in   other  situations.      The 
colour  of  the  middle  tunic  is  yellower  in  the 
larger  trunks  and  more  of  a  reddish  tint  in  the 
smaller  branches.     The  middle  tunic  of  the 
arteries  has  a  degree  of  firmness  sufficient  to 
preserve  the  circular  form  of  the  artery  even 
in  its  empty  state,  and  after  the  other  tunics 
have  been  removed.     This  tunic  possesses  a 
slight  degree  of  strength  and  elasticity  in  the 
longitudinal  direction;    in  the  circular  direc- 
tion it  exhibits  both  these  properties  in  a  more 
marked  degree.    The   strength  and  elasticity 
of  this  tunic  diminish  progressively  from  the 
larger  to  the  smaller  arteries.      There  is  so 
close  a  resemblance  between  the  substance  of 
this  tunic  and  the  yellow  elastic  fibrous  tissue 
of  the  ligamenta  subflava  connecting  the  crura 
of  the  vertebrae,  as  well  in  its  yellow  colour 
and  the  firmness  of  its  fibres,  as  in  its  elastic 
property,  that  many  anatomists  regard  both  these 
structures    as    being  nearly   if   not  perfectly 


identical.  Mr.  Hunter  instituted  a  variety  of 
experiments  to  prove  that  this  tunic  possessed 
a  power  of  contraction  similar  to  that  of  mus- 
cular structure  in  addition  to  its  elasticity ; 
but,  notwithstanding  the  results  of  the  re- 
searches of  this  great  anatomist  and  physio- 
logist, by  which  he  showed,  in  the  clearest 
manner,  that  the  arteries  were  endowed  with 
a  power  of  contraction  totally  distinct  from 
their  property  of  elasticity,  he  never  demon- 
strated, in  a  positive  and  unequivocal  manner, 
the  presence  of  muscular  fibres  in  it,  nor  has  . 
any  other  anatomist,  who,  since  his  time,  may 
have  investigated  the  subject  of  the  structure 
of  this  tunic,  been  more  successful  in  dis- 
covering in  it  any  decided  trace  of  muscular 
fibres.  Beclard*  considers  it  to  be  a  pecu- 
liar elastic  tissue  having  an  intermediate  charac- 
ter between  muscular  and  ligamentous  fibre. 

From  carefully  examining  this  structure,  it 
appears  to  differ  both  from  the  yellow  elastic 
fibrous  tissue  and  from  the  muscular  tissue ; 
possessed  of  the  elasticity  of  the  former,  but 
differing  from  it  in  being  composed  of  fibres 
of  a  softer  consistence  and  more  easily  torn ; 
from  the  latter  it  differs  not  only  in  the  colour 
and  consistence  of  its  fibres,  but  moreover  in 
the  slow  and  gradual  mode  of  its  contraction 
under  the  influence  of  mechanical  or  chemical 
stimuli;  unlike  the  muscular  fibre,  it  retains  its 
power  of  resistance  as  perfectly  in  the  dead  as 
in  the  living  body. 

Bichatf  asserted  that  there  was  a  total  ab- 
sence of  cellular  tissue  in  the  structure  of  the 
middle  tunic  of  arteries.  Meckel,  who  ranks 
higher  as  an  authority  for  matters  of  fact  in 
anatomy,  has  admitted  this  assertion  as  if  it 
were  an  established  fact:  neither  of  these 
authors,  however,  has  advanced  a  single  valid 
argument  or  brought  forward  a  well-founded 
proof  in  support  of  the  correctness  of  this 
statement;  wherefore  we  feel  the  less  reluc- 
tance in  registering  our  dissent  from  such  high 
authorities  on  this  point,  which  we  found  on  the 
consideration  of  the  following  circumstances : — 
First,  there  is  no  analogous  instance  of  an 
organized  structure  receiving  bloodvessels  and 
nerves  into  which  cellular  tissue  does  not  also 
enter  as  a  component  part. 

Secondly,  we  have  the  authority  of  the 
accurate  and  learned  Haller,  in  testimony  of 
the  fact  of  the  fibres  of  the  middle  tunic  of 
the  arteries  having  cellular  tissue  interposed 
between  them,  being,  as  he  expresses  himself, 
"  cellulositate  paucissima  separatae."  Beclard 
entertains  a  similar  opinion  founded  on  the 
circumstance  that  when  a  portion  of  an  artery 
is  stripped  of  its  external  tunic,  granulations 
will  shoot  up  from  the  exposed  surface  of  the 
middle  tunic. 

Thirdly,  we  have  frequently  observed  that, 
when  a  portion  of  an  artery  stripped  of  its 
external  tunic,  is  divided  longitudinally  and 
macerated  in  water  for  several  days,  the  mid- 
dle tunic  increases  in  thickness,  and  its  fibres 
become  more  distinct  and  are  more  easily 
separated  from  each  other ;  by  continuing  the 

*  Anatomic  Generale,  p.  325. 
t  Anatomic  Generale,  torn.  iii. 


ARTERY. 


223 


maceration,  the  intervals  between  the  fibres 
become  greater,  and  as  the  putrefactive  pro- 
cess sets  in  and  advances,  the  whole  substance 
of  the  middle  tunic  takes  on  the  form  of  a 
spongy  mass,  and  ultimately  the  fibres  cease 
to  be  any  longer  discernible,  having  been  re- 
duced to  the  state  of  a  soft  pnlp,  while  the 
cellular  structure  is  rendered  more  evident. 
The  following  appears  to  us  to  be  the  rationale 
of  the  phenomena  above  described  :  the  in- 
crease in  thickness  which  the  middle  tunic  at 
first  undergoes  is  owing  to  the  cellular  tissue 
interposed  between  the  fibres  imbibing  the 
water  in  which  it  has  been  immersed,  in  virtue 
of  its  hygrometric  property ;  and  the  spongy 
appearance  observable  after  the  maceration 
has  been  continued  for  a  length  of  time,  is  the 
result  of  the  cellular  tissue  having  the  property 
of  resisting  decomposition  by  putrefaction 
much  longer  than  the  fibrous  tissue. 

The  internal  tunic  (intima  of  Haller)  is  the 
thinnest  of  the  three ;  it  is  continuous  with 
the  lining  membrane  of  the  heart,  in  extending 
from  which  into  the  arteries  it  forms  a  dupli- 
cature,  contributing  to  the  composition  of  the 
semilunar  valves:  in  the  larger  arteries,  when 
empty,  it  sometimes  forms  longitudinal  folds ; 
in  some  arteries,  such  as  the  popliteal,  and  the 
brachial  at  the  bend  of  the  elbow,  it  presents 
transverse  folds  or  wrinkles;  it  also  forms 
transverse  wrinkles  in  arteries  which  have  re- 
tracted after  amputation :  its  internal  surface, 
which  is  in  contact  with  the  blood  in  the  living 
body,  is  smooth,  polished,  and  bedewed  with 
a  fine  exhalation ;  its  external  surface  adheres 
to  the  internal  surface  of  the  middle  tunics  in 
the  larger  trunks  of  the  arteries;  this  tunic 
may  be  divided  into  two  layers,  the  internal 
of  which  is  thin  and  transparent,  while  the 
external  is  whitish  and  opaque,  having  its  struc- 
ture blended  with  that  of  the  middle  tunic ; 
it  is  the  tunica  cellulosa  Interior  of  Haller, 
and  is  the  seat  of  the  calcareous,  steatomatous, 
and  atheromatous  deposits,  which  so  frequently 
occur  as  morbid  appearances  in  the  coats  of 
the  arteries.  We  do  not  perceive  fibres  nor 
any  other  signs  of  organization  in  the  inner 
layer  of  this  tunic  in  its  healthy  state ;  it  is 
almost  completely  inelastic  and  very  brittle; 
it  tears  with  equal  facility  in  every  direction ; 
compared  with  other  structures  it  bears  the 
closest  resemblance  to  the  arachnoid  mem- 
brane of  the  brain;  the  smooth  and  highly 
polished  condition  of  the  free  surface  of  this 
tunic  is  an  admirable  provision,  whereby  the 
effect  of  friction  in  diminishing  the  velocity 
of  the  passage  of  the  blood  through  the  arte- 
ries is  reduced  to  the  smallest  possible  amount. 

The  following  mechanical  contrivance  ob- 
servable in  the  interior  of  the  arteries  would 
appear  to  be  a  provision  for  facilitating  the 
distribution  of  the  blood  through  the  divisions 
of  the  arterial  system.  As  the  branches  of  the 
arteries  mostly  arise  from  the  trunks  at  acute 
angles,  the  portion  of  the  circumference  of 
their  orifices  on  the  side  next  the  heart  is 
smooth  and  depressed,  forming  a  sort  of  chan- 
nel sloping  gently  from  the  trunk  into  the 
branch,  while  the  opposite  side,  or  that  more 
remote  from  the  heart,  is  bordered  by  a  ridge 


of  a  semilunar  valve-like  form,  composed  of  a 
duplicature  of  the  lining  membrane  in  which 
there  is  included  a  portion  of  the  middle 
tunic ;  the  more  acute  the  angle  at  which  the 
branch  arises,  the  greater  is  the  prominence  of 
this  ridge ;  it  is  altogether  absent  where  branches 
arise  at  right  angles,  as  in  the  case  of  the  emul- 
gent  arteries,  and  where  branches  arise  at  ob- 
tuse angles  to  the  trunk,  it  is  found  at  their 
orifices  on  the  side  next  the  heart. 

The  aorta  and  pulmonary  artery  are  each 
provided  with  three  valves  at  their  origins  from 
the  ventricles ;  these  valves,  called  sigmoid  or 
semilunar  from  their  semicircular  form,  are 
attached  by  their  inferior  borders,  which  are 
convex,  to  the  margins  of  the  semicircular 
flaps  or  festoons,  into  which  the  edge  of  the 
commencement  of  the  middle  tunic  of  the 
artery  is  divided  ;  the  superior  edges  of  each 
of  these  valves,  which  are  free  and  floating, 
form  two  concave  lines,  separated  by  a 
projection  in  the  centre,  in  which  is  con- 
tained a  small  cartilaginous  body,  called 
tubercle,  globulus  Arantii  or  corpus  sesa- 
moideum.  The  portions  of  the  walls  of  the 
artery  corresponding  to  the  valves  are  dilated 
in  the  form  of  pouches,  more  marked  in  the 
aorta  than  in  the  pulmonary  artery ;  these  are 
the  sinuses  of  Valsalva.  The  semilunar  valves 
are  composed  of  a  duplicature  of  the  lining 
membrane  of  the  artery,  including  within  it  a 
thin  but  strong  fibrous  expansion,  continuous 
with  the  fibrous  structure,  which  connects  the 
middle  tunic  of  the  artery  with  the  tendinous 
ring  encircling  the  arterial  opening  of  the  ventri- 
cle; the  free  border  of  each  valve  contains  a  small 
fibrous  cord,  as  described  by  Beclard,  having 
the  globulus  Arantii  attached  to  it  in  its  centre. 
An  increase  or  diminution  in  the  number  of 
the  sigmoid  valves  is  of  rare  occurrence,  more 
frequently  presented  in  the  pulmonary  artery 
than  in  the  aorta,  and  oftener  consists  in  the 
number  of  valves  being  increased  to  four  than 
diminished  to  two.* 

The  mechanism  of  these  valves  is  such  as  to 
prevent  the  blood  flowing  in  a  direction  con- 
trary to  its  regular  course  ;  for  when  that  fluid 
is  propelled  towards  the  ventricle,  they  are 
separated  from  the  parietes  of  the  artery,  and 
being  distended  by  the  column  of  blood  pres- 
sing against  their  superior  surfaces,  they  are 
laid  across  the  area  of  the  vessel,  which  they 
completely  fill  up  by  their  edges  being  thus 
brought  into  perfect  contact  and  the  globuli 
Arantii  meeting  in  the  centre.  There  are  no 
valves  in  the  arteries  in  any  other  situation. 

The  arteries,  like  other  organized  struc- 
tures, are  furnished  with  proper  nutritious 
arteries  and  veins  called  vasa  vasorum.  The 
aorta  and  pulmonary  artery  at  their  commence- 
ment receive  some  branches  from  the  coronary 
vessels  of  the  heart ;  in  all  other  situations  the 
vasa  vasorum  are  supplied  by  the  neighbouring 
bloodvessels ;  the  vasa  vasorum  are  very  evi- 
dent in  the  external  tunic  of  the  arteries,  they 
can  be  traced  until  they  penetrate  the  sub- 
stance of  the  middle  tunic,  but  not  farther ; 

*  Meckel,  Handbuch  der  menschlichen  Anato- 
mic. Band.  i. 


224 


ARTERY. 


they  are  more  numerous  and  larger  in  young 
than  in  adult  and  old  subjects. 

Absorbents  are  not  visible  on  the  coats  of 
any  arteries  except  the  larger  trunks;  however, 
the  removal  of  coagula  formed  in  the  interior 
of  all  arteries  after  the  application  of  ligatures 
may  be  regarded  as  proving  the  existence  of 
absorbents  in  every  part  of  the  arterial  system. 
The   arteries  are  plentifully  supplied    with 
nerves,  of  which  the  aortic  system  receives  more 
in  proportion  than  the  pulmonary  artery,  and 
the  smaller  arteries  more  than  the  larger  trunks. 
The  trunk  of  the  aorta,  the  pulmonary  artery, 
and  the  arteries  of  the  head ,  neck,  thorax,  ab- 
domen, and  those  of  the  genital  organs,  receive 
their  supply  from  the  nerves  of  organic  life. 
These   form  a  very  intricate  plexus  on  their 
surface.     The  arteries  of  the  extremities  receive 
their  supply  of  nerves  from  those  of -animal 
life  in  their  neighbourhood.   Two  sets  of  nerves 
have  been  described  as  being  furnished  to  the 
arteries ;  one  set,  consisting  of  softer  nerves,  of 
a  flattened  form,  are  said  to  be  lost  in  the  cel- 
lular or  external  tunic,  nervi  molles ;  the  other 
set,  more  firm  and  round,  penetrate  the  middle 
tunic,  in  which  they  form  a  thin  membraniform 
expansion,  containing  distinct  fibres.    Meckel* 
justly  considers  the  internal  nerves  as  subdivi- 
sions of  the  larger  flattened  external  branches. 
No  nerves  have  yet  been   discovered  on  the 
umbilical  arteries,  and  the  arteries  of  the  brain 
are  supposed  to  be  without  any.     The  nerves 
of  the  arteries  become  less  apparent  in  old  age. 
The  specific  gravity  of  the  arteries  exceeds 
that   of  distilled   water   in   the   proportion  of 
106  to  100.     They  are  proportionally  lighter 
and  less  dense  than  the  veins ;  while  the  veins 
possess  more  power  of  resistance,  and  are  not 
so  easily  ruptured  as  the  arteries. 

Physical  properties. — Of  the  physical  pro- 
perties of  the  arteries  the  most  remarkable  are 
the  firmness  of  their  parietes,  their  power  of 
resistance,  and  their  elasticity.  It  is  owing 
to  the  firmness,  which  principally  resides  in 
their  middle  tunic,  that  they  preserve  their 
circular  form  in  the  empty  state. 

Their  power  of  resistance  has  been  made  the 
subject  of  experiment  by  Wintringham,f  and, 
more  recently,  by  Beclard,}  from  which  the 
following  results  have  been  obtained. 

Their  power  of  resisting  rupture  is  very  great, 
and  is  generally  in  proportion  to  their  thickness, 
being  greater  in  the  aorta  than  in  the  pulmonary 
artery.  As  the  arteries  diminish  in  size,  their 
absolute  resistance  diminishes ;  however,  as  their 
relative  thickness  and  softness  increase,  their 
extensibility  and  relative  resistance  undergo  a 
proportionate  augmentation.  The  resistance  of 
all  arteries  of  equal  volume  is  not  the  same : 
for  instance,  that  of  the  iliac  artery  is  greater 
than  that  of  the  carotid.  It  is  in  the  external 
tunic  that  the  power  of  resistance  in  the  longi- 
tudinal direction  resides ;  the  resistance  in  the 
circular  direction  is  much  greater,  and  is  owing 
to  the  middle  and  external  tunics  conjointly; 
the  internal  tunic  has  very  little  power  of  re- 

*  Op.  cit. 

t  Experimental  Inquiry  on   some   parts  of  the 
Animal  Structure.     Lond.  1740. 
%  Anatomie  Generale,  p.  373. 


sistance  in  either  direction.  The  middle  and 
internal  tunics  are  as  remarkable  for  their  fra- 
gility as  the  external  is  for  its  toughness  and 
great  power  of  resistance  ;  hence  it  is,  that  when 
a  ligature  is  tightened  on  an  artery,  the  two 
former  are  divided,  while  the  latter  remains 
unbroken,  as  proved  by  the  experiments  of 
Dr.  Jones.* 

The  successful  employment  of  torsion  of  the 
arteries  as  a  means  of  suppressing  haemorrhage 
is  in  like  manner  owing  to  the  greater  power  of 
resistance  possessed  by  the  external  tunic  as 
compared  with  the  other  two.  The  process  by 
which  arteries  are  obliterated  by  torsion  is  thus 
explained  by  M.Amu  ssat,f  to  whom  belongs  the 
merit  of  having  been  the  first  to  propose  and 
practise  it.  The  divided  extremity  of  an  artery 
is  seized  between  the  blades  of  a  forceps,  and 
drawn  out  beyond  the  surface  of  the  wound  : 
the  vessel  is  then  taken  hold  of  with  a  second 
pair  of  forceps  a  few  lines  higher,  and  held 
firmly  while  the  operator  commences  to  twist 
the  forceps  with  which  he  holds  the  extremity 
of  the  vessel  in  the  direction  of  its  axis,  making 
from  five  to  nine  or  ten  turns,  according  to  the 
size  of  the  vessel  operated  upon.  On  examin- 
ing an  artery  which  has  undergone  this  process, 
it  will  be  found  that  the  middle  and  internal 
tunics  of  the  twisted  portion  have  been  broken- 
in  several  places  by  the  external  tunic,  which, 
remaining  unbroken,  is  formed  by  the  twisting 
process  into  a  sort  of  spiral  ligature,  so  tightly 
applied  round  the  inner  tunics  as  to  set  at 
defiance  every  attempt  to  unravel  it  by  twisting 
the  vessel  in  the  opposite  direction. 

The  arteries  are  highly  elastic ;  they  admit  of 
considerable  distension  in  the  longitudinal  di- 
rection, and  quickly  contract  to  their  original 
length  on  the  cessation  of  the  distending  force. 
In  the  transverse  direction  they  yield  less,  and 
after  distension  resume  their  previous  state  with 
greater  force.  When  a  fluid  is  injected  with 
some  force  into  the  arteries  in  the  dead  body, 
they  become  distended  and  elongated ;  and  if, 
when  they  are  in  this  state,  the  force  with 
which  the  injection  was  propelled  be  removed, 
they  will  contract  to  their  previous  state,  or 
nearly  so,  expelling  a  portion  of  the  fluid  which 
had  been  thrown  into  them.  During  life  the 
arteries  are  in  a  state  of  elastic  tension,  so  that, 
when  divided,  their  cut  extremities  retract  with- 
in their  sheath. 

The  arteries  are  endowed  with  the  power  of 
contracting  in  a  gradual  manner,  which  they 
exhibit  under  the  folrowing  circumstances : — 
when  the  passage  of  the  blood  is  stopped  in  the 
principal  artery  of  a  limb,  the  vessel  gradually 
contracts,  its  cavity  is  reduced  in  size,  and 
ultimately  becomes* obliterated  by  degenerating 
into  a  filamentous  band  of  cellular  tissue ;  while 
the  collateral  branches,  taking  up  its  function 
of  conveying  blood  to  the  distant  parts,  are 
proportionally  enlarged, rendered  more  tortuous, 
and  increased  in  length.  In  process  of  time 
the  number  of  enlarged  collateral  branches 
diminishes,  and  one  or  more  vessels  of  in- 
creased size  become  as  it  were  promoted  to 

*  Treatise  on  Haemorrhage.     Lond.  1805. 
t   Archives  Generales  de  Medecine,  t.  xx.  Aout, 
1829,  p.  606. 


ARTERY 


225 


the  station  which  the  principal  trunk  had  held 
in  the  circulation  while  in  its  normal  condition. 
Several  distinguished  anatomists  and  physiolo- 
gists have  considered  the  property  of  elasticity 
of  the   arteries  sufficient  to  account  for  all  the 
phenomena  of   the  circulation   of    the  blood 
through  these  vessels.     This  opinion  has  been 
principally  insisted  on  by  Haller,  Bichat,Nysten, 
and,  at  the  present  day,  by  Magendie;  elasticity, 
however,  can   only  account    for    contractions 
taking   place  in  consequence  of  previous  dis- 
tension, and  is  equally  evident  after  death  as 
during  life :  but  observation  and  experiments 
have  shewn  that,  in  the  living  body,  the  arteries 
possess  an  additional  power  of  contraction,  by 
which  their  calibre  may  be  diminished  in  various 
degrees;    in   some   instances   even   almost  to 
obliteration.      And  this  power  of  contraction 
has  been  considered  by  many   anatomists  to 
indicate  the  existence  of  a  property  of  irritability 
in  the  arteries,  similar  to,  if  not  identical  with 
muscularity.     The  existence  of  irritability  in 
the  arteries  was  denied  by  Haller  in  conse- 
quence of  his  not  having  succeeded  in  render- 
ing it  evident  by  the  application  of  chemical  or 
mechanical  stimuli.     Bichat,  Nysten,  and  Ma- 
gendie,   embraced   a  similar  opinion,   on   the 
strength  of  the  following  facts  : — mechanical  or 
chemical  stimuli,  even  the  galvanic  fluid,  ap- 
plied to  the  surfaces  of  the  arteries,  produce  no 
motions ;  when  the  fibres  of  the  middle  tunic 
are  dissected  off  in  successive  layers  in  living 
animals,  they  are  not  observed  to  display  that 
quivering  motion  visible  among  the   fibres  of 
muscles  similarly  treated.      When  cut  longi- 
tudinally, the  inner  surface  of  the  arteries  does 
not  become  everted  like  that  of  canals,  such  as 
the  intestines,  which  have  a  decidedly  muscular 
tunic  :    they  do  not  contract  when   separated 
from  the  heart.     The  finger  introduced  into  a 
living  artery  is  not  constricted;  stimuli  applied 
to  the  nerves  of  particular  arteries,  or  to  the 
nervous  system  generally,  do  not  produce  con- 
tractions; strong  acids  applied  to  arteries  pro- 
duce a  corrugation  or  crisping  of  their  struc- 
ture, not  a  contraction,  like  that  of  muscular 
structure. 

The  contrary  opinion  as  to  the  existence  of 
irritability  in  the  arteries  has  been  maintained 
by  some  of  the  most  distinguished  and  accurate 
anatomists  and  physiologists,  among  whom  are 
Hunter,  Soemmerring,andVerschuir.  It  may  be 
stated  in  a  general  manner,  as  an  objection  to 
the  arguments  of  Bichat,  founded  on  the  circum- 
stance of  the  arteries  not  having  contracted 
when  stimuli  were  applied  to  them  in  some 
experiments  which  he  performed,  that  other 
irritable  parts,  even  the  muscles  themselves,  do 
not  at  all  times  contract  on  the  application  of 
stimuli.  In  fact,  most  of  the  experiments  de- 
tailed by  Bichat,  as  proving  the  absence  of 
irritability  in  arteries,  have  been  performed  by 
Hunter,  Verschuir,  and  Hastings,  and  with 
results  directly  contrary  to  those  obtained  by 
that  very  distinguished  anatomist.  Verschuir* 
found  that  the  arteries  contracted  when  stimu- 


*  Dissertatio  de  arteriarum  ct  venarum  vi  irrita- 
bili.  Gronigen  1766. 


lated  by  the  mineral  acids,  by  electricity,  and 
the  application  of  the  point  of  a  scalpel.  Dr. 
Thomson  *  also  saw  them  contract  on  the  ap- 
plication of  ammonia,  and  when  punctured 
with  the  point  of  a  fine  needle  in  the  living 
body.  Irritating  the  nerves  by  the  galvanic 
fluid  or  by  caustic  alkalies  has  been  fol- 
lowed by  contraction  of  the  arteries.f  Mr. 
HunterJ  found  that  the  exposure  of  arteries  to 
the  air  was  followed  by  their  contraction  to 
such  an  extent  as  to  produce  their  obliteration. 
An  instance  of  this  we  have  twice  witnessed 
in  the  brachial  artery  when  exposed  during  the 
progress  of  an  operation  for  traumatic  aneurism 
at  the  bend  of  the  elbow.  The  contraction 
of  divided  arteries  is  well  known  to  be  an 
efficient  means  of  arresting  haemorrhage,  in  op- 
position to  the  force  with  which  the  blood 
is  propelled  through  them  by  the  heart's 
action. 

In  conclusion,  we  may  observe  that  the 
arteries  are  proved  to  be  both  elastic  and 
irritable ;  that  elasticity  predominates  in  the 
large  trunks,  and  irritability  in  the  smaller 
branches ;  that  their  irritability,  like  that  of 
muscles,  is  under  the  influence  of  the  nervous 
system,  and  obeys  the  immediate  application 
of  chemical  and  mechanical  stimuli,  the  effects 
of  which  must,  however,  be  very  much  modified 
by  the  influence  of  the  elasticity  with  which 
they  are  endowed.  (See  CIRCULATION.) 

In  men  the  arteries  are  said  to  have  their 
tunics  thicker,  and  to  possess  greater  density 
and  a  higher  specific  gravity  than  in  women. 
The  arteries  are  larger,  more  numerous,  and 
their  coats  are  softer  in  young  persons :  they 
become  more  fragile,  and  their  elasticity  di- 
minishes, in  advanced  life. 

In  the  progressive  development  of  parts  the 
arteries  appear  before  the  heart;  but  in  the 
chick,  during  its  evolution,  the  veins  of  the  yolk 
precede  them  in  their  development,  as  ascer- 
tained by  the  researches  of  Malpighi,§  Haller,|j 
Wolff,1T  Pander,**  and  Rolando.ft 

BIBLIOGRAPHY.  —  Hebenstreit,  Progr.  dc  arte- 
riarum corp.  human,  conliniis,  4to.  Lips.  1739 
(Rec.  in  Haller's  Coll.  Disp.  Anat.  vol.  ii.);  Ejus, 
Progr.  de  vaginis  vasorum,  4to.  Lips.  1740  (Rec.  in 
Haller,  &c.  vol.  ii.);  Ejus,  Progr.  de  flexu  arteri- 
arum, 4to.  Lips.  1741  (Rec.  in  Haller,  &c.  vol.  ii.) 
Monro,  on  the  coats  of  arteries  and  their  diseases,  in 
Ej.  Works,  4to.  Edinb.  De  la  Sone,  Sur  la  structure 
des  arteres  in  Mem.  de  Paris,  1756  and  1762. 
Van  Swieten,  De  arteriae  fabrica  et  efficacia  incorp. 
human.  4to.  Lugd.  Bat.  1725.  Albinus,  De  arteriae 
membranis  et  vasis  in  Ej.  annotat.  academic,  lib.  iv. 

*  Lectures  on  Inflammation.  Edinburgh,  1813. 
p.  75-89. 

t  Vide  a  paper  by  Sir  E.  Home  on  the  Influence 
of  the  nerves  upon  the  action  of  arteries,  Philoso- 
phical Transactions  for  1814. 

\  Treatise  on  the  Blood,  p.  114. 

\  De  formatione  pulli  in  ovo. 

H  Opera  Minora,  t.  ii. 

1   Theoria  Generations . 

**  Journal  de  Progres  des  Sciences  et  des  Tn- 
stitut.  Medicales,  t.  v.  and  Journal  de  Physique, 
t.  Ixviii.  also  his  Beitrage  zur  Entwickelungsges- 
chichte  des  Hunrhcns  im  Eie.  Wu'rtaburg,  1817. 

ft  Journal  Complementaire  du  Diet,  des  Sc. 
Med.,  t.  xi.  p.  323,  et  t.  xii.  p.  34. 

Q 


226 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


Haller,  De  arteriarum  et  venarum  fabrics  in  Ej. 
Up.  miaor.  vol.  i.  Hunter,  on  the  blood,  &c.  4to. 
Load.  1794.  Letierce,  Essai,  &c.  sur  la  membrane 
interne  des  arteres,  Thes.  de  Paris,  1829,  and  in 
Archiv.  Gen.  de  Med.  Nov.  1829.  Haller  resp. 
Berklemann,  De  nervorum  in  arterias  imperio,  4to. 
Gotting.  1744,  and  in  Halleri  Op.  Min.  t.  i. 
Wrisberg,  De  nervis  arterias  venasque  comitantibus, 
in  Ej.  Comment,  vol.  i.  8vo.  Gbttmg.  1800.  Luces, 
Obs.  Anat.  circa  nervos  arterias  adeuntes  et  comi- 
tantes,  4to.  Frft.  a  M.  1810,  Germ,  in  Reil's 
Archiv.  Bd.  ix.  Ribes,  in  Mem.  de  la  Soc.  Med. 
d'Emulation,  t.  viii.  1817,  and  in  Meckel's  Archiv. 
Bd.  v.  Verschuir,  De  Arteriarum  et  Ven.  vi  irri- 
tabili,  &c.  4to.  Groning.  1786.  Parry,  of  the  pulse, 
&c.  8vo.  Lond.  1816;  Ej.  Additional  experiments 
on  the  arteries,  8vo.  Lond.  1819.  Jaeger,  De  ar- 
teriarum pulsu,  8vo.  Viceb.  1820.  Hastings,  De 
vi  contractili  vasorum,  8vo.  Edinb.  1818;  Ejus, 
on  inflammation  of  the  mucous  membrane  of  the 
lungs,  and  inquiry  respecting  the  contractile  power 
of  the  bloodvessels,  &c.  8vo.  Lond.  1820.  Mechel, 
Verlauf  der  Arterien  und  Venen,  in  Ejus  Archiv. 
B.  i.  285  and  450.  Ehrmann,  Structure  des  ar- 
teres, &c.  4to.  Strasb.  1822.  Belmas,  Structure 
des  arteres,  &c.  4to.  Strasb.  1822.  Oppenheim, 
Experimenta  circa  vitam  arteriarum,  4to.  Mannh. 
1822.  Wreden,  Arteriologische  Tabellen.  fol. 
Hannov.  1721.  Chirol,  Tab.  de  toutes  les  arteres 
du  corps  humain,  fol.  Paris.  Muriay,  Descriptio 
arteriarum  corp.  human,  in  tab.  redacta  Diss.  i.-iv. 
4to.  Upsal,  1780-83 ;  8vo.  Lips.  1794 ;  Anglice  a 
A.  Scott,  8vo.  Edinb.  1801.  Barclay,  Description 
of  the  arteries  of  the  human  body,  12mo.  Edinb. 
1812.  Harrison,  Surg.  anat.  of  the  arteries  of  the 
human  body,  2  vol.  12mo.  Dnbl.  1824-25.  Der- 
mott,  Locality  and  distribution  of  the  arteries, 
12mo.  Lond.  1827  ;  Ej.  lilustr.  of  the  arteries,  fol. 
Lond.  1825.  Haller,  Icones  anatomicae,  fasc.  i.- 
vii,  fol.  Gotting.  1743-56.  Bell,  Engravings  of 
the  arteries,  8vo.  Lond.  1811,  1824.  Manec, 
Traite  de  la  ligature  des  arteres,  fol.  Par.  1832. 
Tiedemann,  Tab.  Arteriarum  corp.  humani,  fol. 
Caroliruhae,  1822.  Froriep,  Chirurg.  Anat.  der 
Ligaturstellen  am  mensch.  Kb'rper,  fol.  Weimar, 
1830.  Richerand,  Moyens  de  determiner  exacte- 
ment  la  situat.  et  le  trajet  des  arteres :  Societ. 
Philomat  An  13.  Blizard,  Lect.  '-ciii  the  situation 
of  the  large  bloodvessels,  8vo.  Londi'11798.  *  *  *  * 
The  comparative  anatomy  of  the  arteries  generally 
is  treated  of  in  the  Introd.  of  Blumenbach,  the 
Le9ons  of  Cuvier,  the  systems  of  Carus,  Mechel, 
Ucelli,  Grant,  &c.  Particular  subjects  are  dis- 
cussed by  the  following  writers  : — Carlisle,  Pecu- 
liarity in  the  distribution  of  the  arteries  sent  to 
the  limbs  of  slow-moving  animals,  in  Phil.  Trans. 
1800.  Rapp,  Ueber  das  Wundernetz,  in  Meckel's 
Archiv.  1827.  Barkow,  Eigenthiimlichkeiten 
im  Verlaufe  der  Schlagadern  der  Fischotter,  in 
Meek.  Archiv.  1829,  and  in  Ej.  Disquisit.  circa 
orig.  et  decurs.  Arteriarum, 4to.  Lips.  1829.  Bauer, 
Nonnul.  Avium  systema  arteriosum,  4to.  Berol. 
1825.  Nitsch,  De  avium  arteria  carotide  communi, 
Halae,  1829.  Barkow,  Schlagadersystem  derVbgel, 
in  Meek.  Archiv,  Jahr  1829.  Meckel,  in  Ej.  Ar- 
chiv, Jahr  1826.  Sehlemm,  Blutgefasssystem  der 
Srhlangen,  in  Tiedem.  u.  Treviran.  Zeitschr.  f. 
Physiologic,  2ter  Bd.  Tiedemann,  Anat.  der 
Fischherzens,  4to.  Landshut.  1809.  Rathke,  Herz^ 
kammer  der  Fische,  in  Meek.  Arch.  1826.  Cuvier 
Sf  Valenciennes,  Hist.  nat.  des  Poissons,  t.  i.  Paris, 
1828.  Owen,  on  the  Nautilus  Pompilius,  4to_Lond. 
1832. 

( J.  Hart.) 

ARTERY,  PATHOLOGICAL  CONDI- 
TIONS OF.— Notwithstanding  the  brilliant 
success  that  has  attended  the  labours  of  British 
surgeons  in  the  department  of  their  profession 
having  reference  to  the  arteries, a  success  that  has 
deprived  haemorrhage  of  its  terrors,  and  aneurism 


of  half  its  clanger,  the  pathology  of  the  arterial  sys- 
tem is  still  far  from  being  perfectly  understood. 
Doubtless,  the  appearances  of  disease  in  its  more 
advanced  and  destructive  forms  have  been  ac- 
curately described  as  they  have  been  carefully 
observed,  but  that  invaluable  information  which 
enables  a  practitioner  to  detect  its  early  and 
silent  approach,  to  trace  its  progress  by  con- 
necting each  symptom  with  the  morbid  change 
that  is  going  forward,  and  to  predict  with  accu- 
racy the  time  and  the  manner  of  its  termination, 
is  as  yet  but  very  imperfect.  Many  circum- 
stances have  unavoidably  contributed  to  this. 
It  is  quite  possible  that  arteries  may  be  in  an 
unhealthy  condition  without  presenting  any  in- 
dication of  disease  during  life,  which  is,  therefore, 
in  the  subsequent  examination  overlooked.  It  is 
more  than  questionable  whether  arteritis  occa- 
sions pain,  for  it  has  been  observed  in  situations 
in  which  the  patient  never  complained,  and  as 
persons  do  not  die  from  inflammation  of  the 
arteries,  the  intensity  of  the  disease  has  time  to 
subside,  and  its  effects  only  remain  for  obser- 
vation in  alterations  in  the  coats  of  the  vessels, 
or  in  an  aneurism.  Many  able  and  intelligent 
practitioners  who  have  met  with  aneurisms 
without  number,  have  yet  not  seen  an  example 
of  acute  arteritis,  and  are  disposed  to  consider 
the  red  colour  of  the  internal  membrane  of  the 
vessel  observed  in  cases  presumed  to  be  so  by 
others  as  a  staining  by  the  blood  after  death. 
These  facts  prove  the  imperfection  of  our  know- 
ledge of  the  pathology  of  the  arterial  system  ; 
and  years  of  patient  investigation  must  still 
be  passed  both  by  the  bed-side  and  in  the 
dissecting-room  before  the  dreams  of  hypo- 
thesis give  place  to  the  certainty  of  scientific 
demonstration. 

In  prosecuting  this  inquiry,  that  source  of 
information  so  valuable  in  the  elucidation  of 
other  subjects  in  physiology,  the  experimenting 
on  animals,  is  wholly  closed ;  the  artery  of  the 
animal  bearing  no  analogy  whatever  to  that  of 
man,  either  in  susceptibility  of  disease  or  in  the 
powers  of  reparation  after  injury.  It  appears, 
from  Dr.  Jones's*  experiments,  that  the  artery 
of  a  dog,  if  wounded  only  to  a  moderate  ex- 
tent, is  capable  of  re-uniting  and  of  healing  so 
completely  that  after  a  certain  time  the  cicatri- 
zation cannot  be  discovered,  either  on  its  inter- 
nal or  external  surface ;  whilst  it  is  nearly  certain 
that  in  man  the  wound  of  an  artery  can  only 
be  healed  by  the  complete  obliteration  of  the 
vessel  at  the  spot  where  it  has  been  injured. 
It  is  difficult  if  not  impossible  to  bleed  an 
animal  to  death  by  opening  a  moderately  sized 
artery,  whilst  few  surgeons  would  be  willing  to 
entrust  a  wound  of  a  branch  of  the  temporal  in 
man  to  the  resources  of  nature  alone.  The  facts, 
too,  that  aneurism  is  a  disease  unknown  among 
inferior  animals, — that  it  cannot,  by  any  inge- 
nuity of  contrivance,  be  artificially  produced, and 
that  the  earthy  depositions  so  commonly  met 
with  in  the  arteries  of  aged  persons  are  peculiar 
to  the  human  species,  would  tend  to  shew  that 
some  difference  of  structure  existed,  some  pe- 
culiarity favourable  to  the  production  of  dis- 

*  Jones  on  Haemorrhage,  pp.  107  to  111  incl. 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


227 


ease  in  the  artery  of  the  latter.  Indeed,  in 
examining-  and  comparing  the  artery  of  a  sheep 
or  a  dog  with  that  of  man,  some  very  obvious 
differences  are  apparent:  the  former  is  firmer 
it' not  actually  thicker  in  its  coats;  it  maintains 
its  circular  form  more  completely,  and  seems  to 
possess  the  quality  of  elasticity  in  a  greater 
degree  of  perfection.  These  circumstances, 
however,  are  insufficient  to  account  for  that 
comparative  freedom  from  disease  ;  and  pro- 
bably the  greater  susceptibility  of  man  may  be 
traced  to  the  indulgence  of  certain  habits  and 
propensities  from  which  the  animal  is  debarred, 
and  which,  in  many  other  instances  as  well  as 
in  this,  seem  to  be  the  predisposing  causes 
of  disease  in  the  human  race. 

The  surgical  pathology  of  the  arteries  presents 
itself  in  two  different  though  equally  interesting 
points  of  view,  one  having  reference  to  the 
effects  of  a  wound  or  other  injury  to  a  healthy 
vessel,  embracing  a  consideration  of  the  pro- 
cess by  which  such  injury  is  remedied  or  re- 
paired by  the  efforts  of  nature  alone  or  by  the 
assistance  of  art,  and  the  circumstances  that 
influence  its  success  or  failure ;  the  other  refer- 
ring to  the  appearances  and  consequences  of 
disease,  either  as  it  commences  idiopathically 
within  the  vessel  itself,  or  is  propagated  from 
adjacent  parts  or  structures  to  it.  A  lesion 
of  the  structure  of  an  artery  is  of  but  slight 
importance  provided  its  function  is  unimpaired, 
that  is,  as  long  as  the  blood  it  was  destined  to 
circulate  passes  through  it  or  is  conveyed  by 
some  other  channel  in  the  natural  course  of  the 
circulation  :  even  the  aorta  has  been  obliterated 
without  any  serious  inconvenience  to  the  indi- 
vidual in  whom  it  occurred.  But  when  the 
lesion  is  of  such  a  nature  as  to  interfere  with 
this  function,  when  the  blood  is  allowed  to 
escape  either  externally  as  from  an  open  wound, 
or  internally  as  in  the  different  species  of  aneu- 
rism, results  of  a  most  formidable  nature 
ensue,  greatly  modified,  however,  in  their  cha- 
racter and  consequences  by  a  number  of  cir- 
cumstances highly  deserving  of  attention. 

Wounds  and  injuries  of  arteries.  —  It 
cannot  have  escaped  observation  that  the 
nature  of  the  wound  or  rather  of  the  substance 
that  occasioned  it  exerts  a  striking  influence 
on  the  phenomena  both  of  haemorrhage  and  of 
the  process  by  which  it  is  restrained.  Lacerated 
wounds  seldom  bleed,  although  the  torn  artery 
may  be  left  hanging  out  an  inch  or  more  be- 
yond the  adjacent  surface.  Gun-shot  wounds, 
also,  if  the  artery  is  completely  divided,  are 
not  often  followed  by  haemorrhage,  although 
some  instances  to  the  contrary  occasionally 
happen ;  but  if  the  vessel  is  only  notched  or 
partially  cut,  the  bleeding  is  as  profuse  as  from 
any  other  cause.  If  an  artery  is  wounded  by  a 
cutting  instrument  or  by  puncture,  however,  the 
blood  is  poured  out  most  freely ;  yet  even  here 
there  are  varieties,  according  to  the  size  and 
importance  of  the  vessel,  the  extent  and  direc- 
tion of  the  accompanying  wound,  and  the  cir- 
cumstance of  the  division  of  the  artery  being 
partial  or  complete.  In  like  manner  the  sub- 
sequent progress  of  the  case  will  exhibit  con- 
siderable variety,  and  demonstrate  the  fallacious 


views  of  those  who,  grounding  their  opinions  on 
experiment,  would  limit  the  process  of  recovery 
to  one  operation,  and  regard  the  efforts  of 
nature  as  alike  in  all,  whereas,  as  has  been 
remarked  by  Mr.  Guthrie,  this  process  essen- 
tially depends  on  the  size  and  variation  of 
structure  of  the  artery ;  it  is  not  the  same  in 
large  as  in  small  arteries;  and  it  is  not  even 
quite  the  same  in  the  upper  and  lower  ends  of 
the  same  artery. 

When  a  limb  has  been  torn  off  by  a  cannon- 
shot,  by  the  fall  of  a  tree  on  it,  or  by  any  simi- 
lar violence,  the  arteries  do  not  bleed:  very 
frequently  the  main  trunk  is  seen  hanging  an 
inch  or  more  from  the  wound,  pulsating,  or  at 
least  receiving  an  impulse  from  the  sound 
portion  of  the  vessel,  though  (as  far  as  I  have 
observed)  not  containing  blood  within  it.  It 
hangs  white,  bloodless,  and  flaccid  in  the 
wound,  not  very  unlike  a  piece  of  narrow 
wetted  tape,  and  is  smaller  at  its  extremity 
than  at  any  other  part.  This  narrow  point, 
which,  according  to  Mr.  Guthrie,  is  formed  by 
the  contraction  of  the  arteiy,  is  also  in  his 
opinion  the  only  barrier  to  the  escape  of  the 
blood  ;  for  in  a  case  of  this  description  he  cut 
off  the  end  of  the  artery  at  less  than  an  eighth 
of  an  inch  from  the  extremity,  when  it  bled 
with  the  usual  vigour.  The  extraordinary  op- 
portunities this  gentleman  has  enjoyed,  and 
the  accuracy  of  observation  which  his  writings 
evince,  entitle  his  opinions  to  be  received  with 
great  deference,  although  in  a  physiological  point 
of  view  it  is  difficult  to  conceive  how  an  arteiy 
subjected  to  such  a  lacerating  force  should  not 
have  its  vital  properties  so  much  impaired  as 
to  prevent  its  contracting  at  all,  more  par- 
ticularly at  the  spot  where  it  was  torn  across, 
and  where,  therefore,  the  greatest  injury  was 
sustained.  At  the  same  time  there  is  no  other 
mode  of  explaining  the  case.  All  that  portion 
of  the  artery  that  is  pendulous  from  the  wound 
appears  to  be  smaller  in  diameter  than  in  its 
healthy  state ;  there  is  cellular  tissue  at  its  torn 
extremity,  but  it  is  not  injected  with  blood, 
and  the  coagulum,  if  any,  within  the  vessel,  is 
so  small  as  to  be  incapable  by  its  mechanical 
resistance  of  preventing  the  escape  of  the  blood. 
As  there  are  scarcely  any  two  accidents  at- 
tended by  exactly  the  same  degree  of  injury, 
it  is  probable  that  nature  in  such  cases  possesses 
different  resources.  In  one  case  where  the  leg 
had  been  torn  oflf  by  the  falling  of  a  tree,  and 
left  attached  merely  by  a  portion  of  the  skin 
over  the  gastrocnemius  muscle,  the  posterior 
tibial  artery  hung  nearly  three  inches  from  the 
wound.  As  the  man  had  been  carried  a  dis- 
tance of  eleven  miles,  and  seemed  much  ex- 
hausted, it  was  not  deemed  right  to  attempt 
more  at  the  moment  than  merely  to  relieve  him 
of  the  annoyance  of  the  pendulous  portion  of 
the  limb  by  cutting  through  the  skin.  This 
was  performed  incautiously,  for  no  inconve- 
nience was  apprehended  ;  about  an  inch  of  the 
extremity  of  the  artery  was  removed,  and  it 
bled  just  as  in  Mr.  Guthr'ie's  case.  In  another 
instance  where  the  arm  was  shattered  by  a 
steam-engine  with  such  violence  that  some  of 
the  muscles  torn  from  their  attachments  re- 

Q  2 


228 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


mained  upon  the  wheel,  the  artery,  divided  in 
the  subsequent  amputation  more  than  two 
inches  above  the  wound,  did  not  pour  out  one 
drop  of  blood.  In  others,  still,  the  cellular 
sheath  of  the  artery  has  been  seen  injected 
wi'th  blood  in  a  state  of  coagulation,  the  pres- 
sure of  which  on  its  orifice  seemed  to  be 
sufficient  to  prevent  bleeding. 

We  are  told  that  the  observation  made  by 
Amussat,*  that  in  gun-shot  wounds  where  all 
the  parts  were  lacerated,  the  extremities  of 
even  the  larger  vessels  did  not  bleed,  suggested 
to  him  the  application  of  the  phenomenon 
to  practical  surgery,  and  led  to  the  practice 
of  the  torsion  of  arteries.  This  operation  con- 
sists in  laying  bare  a  portion  of  the  divided 
artery,  and  carefully  detaching  it  from  the  sur- 
rounding cellular  membrane  until  its  own  cel- 
lular tunic  is  distinctly  to  be  seen  ;  it  is  then 
seized  with  a  forceps,  not  unlike  the  common 
artery-forceps  of  Bell,  and  twisted  on  its  axis 
until  the  extremity  engaged  between  the  blades 
is  completely  detached  by  the  torsion.  This 
forms  something  like  a  knot  or  knuckle  at  the 
end  of  the  vessel,  which  mechanically  blocks 
it  up ;  a  coagulum  is  formed  within,  and  the 
remainder  of  the  process  is  said  nearly  to  re- 
semble that  which  succeeds  the  application  of 
a  ligature.  Not  having  practised  torsion  on 
a  vessel  of  any  considerable  size  in  the  human 
subject,  nor  had  an  opportunity  of  examining 
after  death  a  case  thus  treated,  I  am  unable  to 
comprehend,  with  sufficient  precision,  the  exact 
process  that  is  established.  In  experimenting 
on  the  femoral  arteries  of  dogs,  I  have  always 
found  that  the  immediate  obstacle  to  the  flow 
of  blood  was  a  coagulum  situated  at  the  orifice, 
and  apparently  entangled  in  the  lacerated  cel- 
lular coat;  but  for  the  reasons  already  men- 
tioned, little  confidence  can  be  placed  in  such 
investigations. 

Hitherto  we  have  been  considering  those 
wounds  of  arteries,  which,  however  important 
in  other  respects,  are  not  attended  by  haemor- 
rhage, and  although  ignorant  of  the  operations  of 
nature  in  effecting  this  result,  it  is  of  the  less  con- 
sequence, inasmuch  as  it  is  not  likely  we  shall 
attempt  to  imitate  them,  or  entrust  a  large- 
sized  vessel  to  torsion  alone.  The  wounds  of 
arteries,  accompanied  by  loss  of  blood,  present 
themselves  under  very  different  circumstances; 
there  is  always  anxiety,  agitation,  and  dismay  on 
the  part  of  the  sufferer,  and  it  may  be  that 
promptness  and  decision  in  the  practitioner 
shall  be  required  to  preserve  life.  In  any  of 
these  awful  situations,  coolness  and  self-pos- 
session can  alone  ensure  a  freedom  from  em- 
barrassment, and  these  qualities  cannot  be  ex- 
pected in  any  individual  who  has  neglected  to 
make  himself  acquainted  with  the  nature  of 
the  mischief  that  has  occurred,  and  the  means 
by  which  it  may  be  remedied. 

The  phenomena  attendant  on  arterial  hae- 
morrhage occasioned  by  incised  and  punctured 
wounds  exhibit  remarkable  varieties,  according 
to  the  size,  and  of  course  to  the  structure  of 
the  vessel ;  to  the  circumstance  of  its  having 

*  Dictionaire  de  Chirurgie  de  Rust,  torn.  ii. 


been  fairly  divided,  or  only  notched,  or  punc- 
tured ;  to  the  wound  being  so  large  and  putu- 
lous  as  freely  to  permit  the  escape  of  all  the 
blood  externally,  or  so  small  or  oblique  that 
the  fluid,  though  withdrawn  from  the  circula- 
tion, is  still  retained  within  the  limb.  There  is 
still  another  condition  of  wounded  artery  in 
which  the  blood  that  escapes  from  it  is  poured 
into  an  adjacent  vein, and  continues  to  circulate, 
though  not  in  its  proper  vessel.  However, 
these  latter  cases  are  usually  considered  and 
described  as  forms  of  aneurism,  and  will, 
therefore,  not  be  noticed  until  there  is  an  op- 
portunity of  comparing  the  different  species  of 
that  disease  one  with  another. 

When  a  large  artery  is  divided  in  an  open 
wound,  it  may  happen  that  the  patient  dies 
almost  instantaneously,  not  from  the  absolute 
quantity  of  blood  lost,  but  from  its  being  with- 
drawn too  suddenly  from  the  circulation,  just 
as  syncope  is  often  produced  by  the  rapid 
abstraction  of  blood  in  the  common  operation 
of  phlebotomy.  However,  this  is  not  uniformly 
the  case,  and  experience  has  proved  that  vessels 
of  such  size  and  importance  as  the  carotid  and 
femoral  arteries  may  be  divided,  and  yet  suffi- 
cient time  allowed  for  the  successful  interposi- 
tion of  art.  Mr.  Guthrie  states,  that  when  the 
femoral  artery  is  cut  across  in  the  upper  part  of 
the  thigh,  the  patient  does  not  always  bleed 
to  death,  although  frequently  lost;  while  if  the 
division  takes  place  in  the  middle  or  lower  half 
of  the  thigh,  the  bleeding  will  probably  cease 
of  itself.  When,  however,  an  artery  of  still 
smaller  size  is  divided,  the  powers  of  nature 
are  almost  always  competent  to  restrain  the 
haemorrhage,  and  consequently  it  is  from  an 
examination  of  vessels  of  this  class  under  such 
circumstances  that  a  knowledge  can  be  ob- 
tained of  the  nature  and  extent  of  these 
powers. 

When  a  vessel  of  moderate  size  is  divided, 
the  blood  is  poured  forth  in  jerks  from  its 
open  mouth  in  a  large  and  full  stream ;  soon, 
however,  this  stream  is  seen  to  become  dimi- 
nished in  size,  and  most  probably  it  ceases  to 
flow  per  saltum.  If  the  patient  faints,  the 
bleeding  perhaps  ceases  altogether,  nor  will  it 
be  renewed  unless  accident  or  indiscretion  gives 
to  the  blood  an  impetus  sufficient  to  overcome 
the  obstacle  that  opposes  its  exit,  whatever  that 
may  be.  When  the  artery  is  divided,  its  middle 
coat  retracts  immediately  that  its  natural  state 
of  tension  is  removed,  withdrawing  with  it  the 
lining  membrane,  but  leaving  the  cellular,  to 
which  it  is  but  loosely  attached,  hanging  out 
beyond  it.  It  contracts,  too,  in  diameter,  as  is 
evidenced  by  the  diminished  stream  of  blood. 
The  power  by  which  this  contraction  and  re- 
traction are  performed  is  a  vital  property  inhe- 
rent in  the  artery  itself;  it  has  been  called 
muscularity,  and  endless  arguments  have  thus 
been  raised  about  a  name,  as  if  no  tissue  in  the 
body  but  muscle  could  be  capable  of  contrac- 
tion. But  it  operates  in  a  manner  very  different 
from  the  rapid  and  decided  contraction  of  muscle ; 
it  is  slow,  gradual,  and  continued,  and,  there- 
fore, is  longer  in  bringing  the  large  vessel  into 
a  state  favourable  for  the  suppression  of  haemor- 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


229 


rhage  than  the  small  one.  The  next  step  is 
the  entanglement  of  blood  in  the  cellular  coat 
of  the  vessel  and  its  consequent  coagulation 
when  it  comes  to  press  in  the  most  advantageous 
direction  on  its  open  mouth,  and  the  haemor- 
rhage is  stopped. 

Thus  the  immediate  agent  of  nature,  in  the 
suppression  of  haemorrhage,  is  pressure  effected 
by  the  clot  of  blood,  whilst  the  vessel  is  placed 
by  its  own  properties  in  the  condition  most  fa- 
vorable to  the  operation ;  and  it  is  curious  to  ob- 
serve how  universally  the  principle  has  been 
acted  on,  though  probably  first  suggested  by 
accident  or  empiricism.  The  burning  iron  of 
the  older  surgeons  produced  the  pressure  of  an 
eschar ;  agaric  and  sponge  entangled  the  blood 
and  retained  a  coagulum  on  the  spot;  even  the 
more  modem  invention  of  the  ligature  is  in  the 
first  instance  only  pressure,  but  with  the  mani- 
fest advantages  of  being  applied  directly  and 
immediately,  of  being  firm  and  not  likely  to  slip, 
and  independent  of  rest,  position,  and  bandage, 
which  are  indispensable  when  other  modes  of 
compression  are  had  recourse  to. 

But  the  permanent  suppression  of  arterial 
hemorrhage  can  only  be  effected  by  the  actual 
obliteration  of  the  vessel  at  the  spot  where  it 
had  been  opened  or  divided,  a  process  that  is 
the  result  of  inflammation  of  the  lining  mem- 
brane, and  of  the  coagulating  lymph  thereby 
poured  out,  or  of  the  artery  ceasing  to  transmit 
blood  through  it,  and  thus  becoming  as  it  were 
useless  in  the  economy.  Both  these  influences 
are  exemplified  in  the  permanent  cure  of  a 
wounded  artery,  for  in  an  incredibly  short  space 
of  time  after  the  external  coagulum  has  been 
formed,,  lymph  is  effused  from  the  wound  in 
the  vessel :  and  internally,  between  this  lymph 
and  the  nearest  collateral  branch,  another  coa- 
gulum of  blood  is  formed,  to  which  a  consi- 
derable degree  of  importance  has  been  attached, 
though  probably  without  sufficient  reason.  It 
cannot  be  very  instrumental  in  controlling  hae- 
morrhage, because  it  does  not  occupy  the  entire 
capacity  of  the  artery  :  its  shape  is  conical,  the 
base  lying  on  the  lymph  poured  out  from  the 
wound,  from  which  it  gradually  tapers  to  the 
next  branch,  and  it  seems  to  be  formed  of  a  small 
quantity  of  the  blood,  which,  being  pushed  into 
that  branch,  remains  there,  is  placed  out  of  the 
current  of  the  circulation,  and  must  coagulate. 
The  transmission  of  blood  to  the  limb  below 
is  now  to  be  effected  through  the  medium  of  the 
anastomosing  vessels,  which  for  this  purpose 
become  proportionably  enlarged.  This  quality 
possessed  by  arteries  of  increasing  their  own 
diameters,  or  in  other  words  of  accommodating 
themselves  to  their  contents,  is  curious  and 
interesting,  and  although  not  admitting  of  ex- 
planation, cannot  for  a  moment  be  doubted. 
No  fact  has  been  more  satisfactorily  proved  by 
dissection,  and  like  the  contractility  of  the  artery 
already  noticed,  the  effects  of  this  power  exhibit 
themselves  gradually  and  slowly.  The  circu- 
lation of  the  limb  seems  scarcely  to  be  inter- 
rupted, for  in  a  few  minutes  the  arteries  below 
appear,  as  has  been  observed  by  Dupuytren, 
like  soft  cords  under  the  finger,  evidently  filled 
with  blood,  but  totally  devoid  of  pulsation.  It 


is  a  long  time  before  this  latter  proof  of  a  re- 
stored activity  in  the  circulation  comes  to  be 
perceptible,  and  perhaps  is  never  again  equal 
to  what  it  had  been  before  the  occurrence  of 
the  accident.  The  external  wound,  of  course, 
heals  like  any  other  of  a  similar  nature,  and  it 
is  rare  that  the  limb  experiences  any  incon- 
venience subsequently.  The  internal  coagulum 
is  soon  absorbed,  and  in  process  of  time  the 
vessel,  from  the  point  of  division  to  the  next 
branch  above  and  below,  degenerates  into  an 
impervious  ligamentous  cord. 

Such  is  the  progress  of  events  when  the 
efforts  of  Nature  are  sufficient  to  arrest  the 
bleeding;  but  after  all  it  is  a  fortunate  case 
that  ends  thus,  and  experience  teaches  that 
there  is  little  wisdom  in  leaving  a  moderately 
sized  artery  to  her  resources  alone.  What  more 
frequently  happens  is  this :  the  artery  retracts 
and  contracts  it  is  true,  and  a  coagulum  forms, 
which,  as  the  patient  becomes  faint  or  weak,  is 
allowed  to  become  consolidated,  and  for  that 
time  is  sufficient  to  save  him.  But  he  recovers, 
or  perhaps  he  uses  some  stimulus  or  some  ex- 
citement, and  the  renewed  circulation  gradually 
loosens  the  clot,  and  a  fresh  gush  of  blood  takes 
place.  This  recurs  frequently,  and  an  hamor- 
rhagic  disposition  is  formed;  the  patient  be- 
comes pale  and  exsanguineous,  anxious,  and  in 
continual  agitation,  and  without  the  interven- 
tion of  art  has  but  a  slender  chance  of  sur- 
viving. In  these  cases,  art  adopts  the  principle 
of  the  natural  cure,  only  regulating  its  force, 
and  ensuring  its  continued  operation  for  the 
requisite  period.  The  first  object  to  be  at- 
tained is  the  application  of  a  sufficient  degree 
of  pressure  to  control  the  bleeding  :  the  second 
to  maintain  that  pressure  for  a  length  of  time 
to  ensure  the  obliteration  of  the  vessel.  This 
is  not  the  place  to  discuss  the  various  methods 
that  have  been  adopted  for  the  accomplishment 
of  these  ends  ;  suffice  it  that  the  superiority  of 
the  ligature  has  been  so  far  proved  by  expe- 
rience, that  few  surgeons  of  the  present  day 
would  feel  satisfied  in  entrusting  a  large  or  im- 
portant vessel  to  a  less  powerful  or  enduring 
compression.  But  the  ligature  is  in  itself  not 
unfrequently  a  cause  of  great  and  frightful  mis- 
chief, and,  therefore,  it  will  be  necessary  to 
examine  into  all  the  circumstances  connected 
with  this  part  of  the  subject. 

In  practice,  a  ligature  is  applied  around  an 
artery  under  two  different  circumstances ;  one, 
in  the  case  of  the  wounded  and  bleeding  artery, 
it  is  placed  on  the  open  orifice  of  the  vessel ; 
the  other,  in  the  treatment  of  aneurism,  the 
artery  is  taken  up  and  tied  at  a  part  where  it 
is  supposed  to  be  sound  and  uninjured.  When, 
in  either  of  these  cases,  an  artery  is  tied,  the 
first  effect  is  obviously  to  bring  its  opposite 
sides  into  apposition,  and  to  arrest  the  flow  of 
blood  through  it.  At  the  same  time  that  the 
internal  and  fibrous  coats  being  shorter  and  less 
tough  yield  under  its  pressure  and  are  divided 
completely,  leaving  the  cellular  coat  entire, 
still  sustaining  the  ligature  in  its  place.  The 
consequences  of  this  division  of  the  internal 
coats  are  very  similar  to  those  already  explained 
as  following  the  complete  section  of  the  artery  ; 


230 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


there  is  the  same  effusion  of  lymph,  the  for- 
mation of  internal  coagulum  of  the  same  conical 
shape  and  to  the  same  extent,  the  diversion  of 
the  circulation  through  the  collateral  branches, 
and  if  the  case  proceeds  favorably,  the  ultimate 
obliteration  of  the  tube  between  the  place 
occupied  by  the  ligature  and  the  next  anasto- 
mosing branch.  But  the  ligature  is  still  to  be 
attended  to.  The  portion  of  the  cellular  coat 
included  within  its  noose  sloughs  and  dies, 
and  is  to  be  detached  from  the  remainder 
by  the  absorption  of  the  adjacent  sound  part. 
This  process  takes  place  at  different  periods  of 
time  according  to  the  size  of  the  vessel;  it 
separates  from  the  subclavian  about  the  twenty- 
second  day  after  the  operation,  from  the  femoral 
about  the  sixteenth,  and  from  the  brachial  so 
early  as  the  twelfth  or  fourteenth.  Unfor- 
tunately matters  do  not  always  proceed  thus 
favorably,  and  the  separation  of  the  ligature  is 
the  commencement  of  a  series  of  evils  to  the 
patient  and  of  embarrassment  to  the  surgeon, 
that  can  scarcely  be  paralleled  in  the  practice 
of  surgery.  It  has  been  found,  however,  by 
experience,  that  a  ligature  placed  on  an  artery 
that  has  been  fairly  divided,  is  more  rarely 
followed  by  those  ill  consequences  that  fre- 
quently ensue  when  its  continuous  tube  is  tied, 
and  as  this  latter  operation  is  so  intimately 
connected  with  the  subject  of  aneurism,  and  as 
it  will  be  necessary  to  become  acquainted  with 
the  phenomena  of  inflammation  in  these  struc- 
tures, in  order  to  understand  those  of  secon- 
dary or  consecutive  haemorrhage,  this  part  of 
the  subject  cannot  at  present  be  so  favorably 
discussed. 

Morbid  states  of  arteries.  Aneurism. — 
Aneurism  (amt^ur/xc?,  vel  a«t,'£t;c-/Aoc.)  is  a 
term  of  such  extensive  application  as  to  pre- 
clude the  possibility  of  an  accurate  definition. 
It  has  been  employed  by  Corvisart  and  others 
to  designate  certain  affections  of  the  heart,  but 
is  now  most  generally  used  to  express  a  disease 
produced  by  a  dilatation  of  an  artery,  or  by 
solution  of  continuity  in  one  or  all  of  its  coats. 
It  is  also  applied  to  any  distended  condition  of  a 
part  of  the  vascular  system,  such  as  occurs  when 
an  unnatural  communication  is  formed  between 
an  artery  and  vein,  constituting  the  diseases  of 
aneurismal  varix  and  varicose  aneurism.  The 
name  of  aneurism  by  anastomosis  has  also 
been  given  to  those  bloody  tumours,  which,  at 
first  appearing  only  as  marks  or  stains  occa- 
sioned by  a  congeries  of  vessels,  increase  either 
with  the  growth  of  the  individual,  or  according 
as  the  vascular  system  may  be  accidentally  ex- 
cited, until  finally  they  produce  results  of  a 
most  formidable  description. 

Aneurisms  have  been  classed,  first,  as  to  the 
condition  of  the  coats  of  the  artery,  a  dilata- 
tion of  them  being  considered  as  the  true  aneu- 
rism, whilst  a  rupture  or  ulceration  of  them 
constitutes  the  false :  and,  secondly,  as  to  the 
condition  of  the  effused  blood,  which,  if  it  is 
contained  within  a  sac  or  bag,  constitutes  the 
circumscribed  {form  of  the  disease,  or  if  it  has 
been  poured  out  throughout  the  circumjacent 
cellular  tissue,  forms  the  diffused  aneurism. 
The  nature  of  aneurism,  however,  will  be  better 


understood  by  considering  it  to  consist  of  such 
a  lesion  of  an  artery  as  will  permit  the  passage 
of  a  portion  of  the  blood  out  of  the  usual  course 
of  the  circulation,  though  not  out  of  the  vicinity 
of  the  injured  or  diseased  vessel,  and  according 
to  the  different  circumstances  under  which  this 
can  occur,  the  disease  will  be  found  to  arrange 
melf  under  the  following  distinct  species.  In 
the  first  four  of  these  the  effused  blood  is  either 
partially  or  entirely  withdrawn  from  the  circu- 
lation, and  becomes  coagulated  in  its  new 
situation  :  in  the  others  it  passes  from  the  usual 
course  of  the  circulation,  but  is  not  withdrawn 
entirely  from  it,  and  consequently  does  not 
coagulate. 

1.  Where  by  rupture  or  ulceration  of  the 
internal  and  middle  coats  of  the  vessel,  the 
blood  is  propelled  against  the  external  cellular 
coat,  which  becomes  thus  distended  into  a  pouch 
containing  within  it  the  extra vasated  blood,  in 
a  more  or  less  perfect  state  of  coagulation, 
which   pouch  is  termed  the  aneurismal  sac. 
This  is  circumscribed  false  aneurism. 

2.  The  true  aneurism  is  when  all  the  coats 
of  an  artery,  in  one  particular  part  of  its  cir- 
cumference, are  so  far  deprived  of  their  elastic 
properties  as  to  yield,  become  distended,  and 
form  a  pouch,  in  which  the  contained  blood  is 
similarly  circumstanced. 

3.  It  is  not  difficult  to  conceive  that  the  sac 
of  a  true  aneurism,  as  just  described,  will  not 
long   endure  its  state  of  unnatural  distension 
before  its  internal  and  fibrous  coats  either  ulce- 
rate or  rupture,  and  then  an  aneurismal  sac  is 
formed,  consisting  in  one  part  of  all  the  coats 
of  the  dilated  vessel,  and  in  the  other  of  the 
cellular  tunic  alone.    This  is  obviously  a  mixed 
form  of  aneurism. 

4.  When  there  is  a   wound,    rupture,    or 
ulceration  of  all  the  coats  of  an  artery,  in  such 
wise  as  to  permit  the  escape  of  the  blood  into 
the  adjacent  cellular  tissue,  a  dijfused  aneurism 
is  formed.      This,  for  reasons  that  need   not 
explanation,  will  be  most  frequently  observed 
to  succeed  to  wounds  or  punctures  of  vessels, 
but  it  may  also  be  the  consequence  of  an  acci- 
dental rupture  of  the  sac  of  a  circumscribed 
aneurism  allowing  the  Wood  to  pass  through 
it,  and  spread  itself  (as  it  generally  does)  in 
every  direction  throughout  the  loose  cellular 
tissue  of  the  entire  limb. 

5.  A  direct  and  immediate  communication 
may  be  established  between  an  artery  and  a 
vein  lying  close  upon  it,  as  by  the  passage  of  a 
lancet  transfixing  one  vessel  and  entering  the 
other.    This  is  the  aneurismal  varix,  obviously 
occurring  with  greater  frequency  as  the  result 
of  a  wound,  bur  nevertheless  occasionally  seen 
as  the  product  of  disease. 

6.  A  small  circumscribed   aneurismal   sac 
has  been  found  situated  between  an  artery  and 
vein  so  transfixed,  communicating  with  both, 
and  permitting  a  transmission  of  blood  from 
one  vessel  into  the  other.     This  variety  has 
been  named  the  varicose  aneurism. 

7.  A  portion  of  blood  may  be   contained 
within  a  new  and  diseased  formation  of  cellu- 
lar structure,  the  precise  nature  of  which  is 
not  understood.    The  trunks  of  the  arteries  in 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


231 


the  neighbour! lood  are  neither  distended  nor 
ruptured,  and  the  blood  within  it  passes  through 
the  general  circulation,  and  of  course  does  not 
coagulate.  It  is  difficult  to  class  this  disease 
with  aneurism  in  any  form,  yet  is  it  termed  the 
aneurism  t>i/  OtUUtomotU. 

No  part  of  the  natural  history  of  any  disease 
can  be  more  interesting  than  that  which  has 
reference  to  its  causes,  whether  predisposing 
and  remote,  or  immediately  exciting.  Cer- 
tainly, when  an  aneurism  has  been  formed,  a 
knowledge  of  the  circumstances  that  occa- 
sioned it  will  not  be  very  useful  in  contributing 
to  its  removal,  although  it  may  often  assist  in 
forming  a  prognosis  as  to  the  result  of  an 
operation  :  yet  if  it  can  be  made  available  in 
tin;  prevention  of  the  disease,  it  must  prove  of 
no  inconsiderable  value.  It  is  admitted  that 
aneurism  frequently  appears  suddenly  as  the 
result  of  a  blow,  a  strain,  or  some  violent  exer- 
tion, the  patient  being  conscious  of  something 
having  torn  or  given  way  within  him.  With 
still  greater  frequency  it  occurs  without  any 
such  consciousness  on  the  part  of  the  sufferer, 
and  persons  have  borne  this  formidable  disease 
about  them  for  months,  and  even  for  years, 
not  only  without  being  themselves  aware  of  its 
existence,  but,  if  situated  internally,  without 
its  being  recognized  by  their  professional  at- 
tendants ;*  and  it  often  happens  that  a  patient 
complains  of  the  crookening  of  the  fingers  or 
the  numbness  of  the  foot,  unmindful  of  the 
tumour  under  the  clavicle  or  in  the  popliteal 
space.  Without  denying  that  an  artery,  in  a 
perfectly  healthy  condition,  can  become  the 
seat  of  aneurism,  because  there  are  too  many 
facts  apparently  in  support  of  such  an  opinion, 
it  may  be  remarked  that  if  such  was  generally 
or  even  frequently  the  case,  the  disease  ought  to 
be  much  more  common  amongst  the  labouring 
poor,  and  also  that  it  should  prevail  amongst 
some  particular  trades.  These  considerations 
lead  to  a  belief,  that  previous  to  the  occurrence 
of  spontaneous  aneurism,  the  artery  has  under- 
gone some  change  predisposing  to  it,  although 
it  may  not  be  so  easy  to  point  out  the  nature 
of  that  change,  or  the  causes  that  lead  to  its 
production. 

It  is  observed  that  aneurism  is  of  far  less 
frequent  occurrence  in  woman  than  in  man ; 
a  comparison  between  the  numbers  of  internal 
cases  proving  this  fact  in  a  remarkable  manner, 
and  in  cases  of  external  aneurism  still  more  so. 
It  is  very  rare  to  meet  writh  a  popliteal  aneu- 
rism in  a  female.  Certainly,  the  more  labo- 
rious habits  and  constant  exposure  to  accident 
in  the  one  sex  may  in  some  respects  serve  to 
account  for  this  circumstance,  but  to  those 
who  know  that  in  many  places  women  are 
obliged  to  undergo  at  least  as  much  hardship 
and  fatigue,  the  explanation  will  be  far  from 
satisfactory.  Again,  it  has  been  stated  that 
certain  pursuits  of  life  predispose  to  aneurism, 
inasmuch  as  it  prevails  amongst  coachmen  and 
postilions,  but  there  never  has  been  even  a 
plausible  reason  offered  to  explain  this  greater 

*  A  very  curious  case  of  this  description  is  related 
in  the  Dublin  Hospital  Reports,  vol.  v.  p.  167. 


liability  of  particular  callings.  It  cannot  be 
the  bent  positions  of  the  limbs  of  such  per- 
sons, because  many  other  classes,  studious 
persons  for  instance,  maintain  similar  postures 
for  a  longer  time  and  with  greater  frequency, 
yet  is  not  aneurism  common  amongst  them. 
Neither  will  the  sudden  stretching  of  the  limb 
by  pressing  the  foot  against  the  stirrup  or  foot- 
board in  managing  the  horses  throw  any  light 
upon  the  subject,  for  it  is  found  by  experiment 
that  no  force  will  rupture  a  healthy  artery  short 
of  what  would  also  tear  asunder  the  ligaments 
of  the  adjacent  joints.  Allowing,  therefore, 
the  accuracy  and  truth  of  these  observations, 
their  explanation  is  still  to  be  sought  for. 

Some  have  supposed  that  old  age,  and  the 
deposit  of  earthy  material  which  is  formed  in 
the  arteries  at  that  period,  are  predisposing 
causes  of  aneurism ;  yet,  if  this  was  the  case, 
the  disease  should  be  very  prevalent  indeed 
among  those  advanced  in  life,  whereas  it  is 
in  reality  almost  as  rare  as  in  infancy  or  early 
youth.  Of  fifteen  cases  of  large  aneurism 
operated  on,  only  two  had  exceeded  the  age 
of  forty  years,  the  average  of  all  being  but 
thirty-one  and  a  half ;  and  if  a  larger  number 
of  cases  (inclusive  of  the  internal  forms  of  the 
disease)  were  collected  and  compared,  it  would 
probably  be  shewn  to  be  considerably  less. 
With  respect  to  the  earthy  deposit  alluded  1o, 
it  is  found  between  the  fibrous  and  internal 
coats  closely  adhering  to  the  latter,  from  which 
it  can  scarcely  be  separated :  it  is  disposed  in 
thin  laminae  or  plates  of  different  sizes,  the 
largest  being  seldom  greater  than  a  spangle, 
and  these  earthy  spots  are  distinct  and  separate, 
not  running  into  or  connected  with  each  other, 
and  never  encircling  the  vessel  with  an  un- 
interrupted bony  ring.  They  are  supposed  to 
render  an  artery  friable  and  brittle,  and  there- 
fore to  predispose  to  aneurism,  and  have  been 
considered  by  some  to  be  the  products  of 
arterial  inflammation.  Unfortunately  the  origin 
and  progress  of  this  earthy  degeneration  have 
not  yet  been  satisfactorily  traced.  Scarpa* 
seems  to  regard  it  as  arising  from  the  same 
cause  that  produces  the  steatomatous  deposit, 
and  states  that  it  cannot  be  said  to  be  proper 
to  old  age,  as  it  is  sometimes  met  with  in 
patients  who  are  not  much  advanced  in  life.  I 
have  seen  these  earthy  depositions  in  the  aorta 
of  a  female  not  twenty -five  years  of  age,  which 
was  also  highly  inflamed  and  covered  with 
spots  of  soft  steatomatous  deposit,  but  still 
that  is  far  from  proof  of  its  being  the  product 
of  active  inflammation,  or  of  its  rendering  the 
artery  weak  or  disposed  to  aneurism. 

Of  any  number  of  subjects  above  the  age 
of  sixty  brought  into  a  dissecting-room,  three- 
fourths  will  be  found  with  this  earthy  dege- 
neration in  some  of  the  arteries,  yet  the  in- 
frequency  of  aneurism  amongst  old  patients 
has  been  already  remarked.  Again,  this  de- 
posit has  been  seen  in  the  sac  of  a  true  aneu- 
rism, a  circumstance  that  would  shew  it  did 
not  greatly  interfere  with  the  distensibility  of 
the  arterial  tunics  or  render  them  more  friable, 

*  On  Aneurism,  page  90. 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


232 

and,  lastly,  a  large  and  important  vessel  in 
this  condition  has  been  tied  without  its  being 
crushed  or  broken  down  short,  and  being  fol- 
lowed by  consecutive  haemorrhage.  From 
these  observations  some  reasonable  doubt  may 
be  entertained  of  these  deposits  being  the 
result  of  inflammation,  more  particularly  as, 
at  the  period  of  life  alluded  to,  there  is  an 
evident  disposition  to  the  formation  of  earthy 
deposits  in  many  structures  and  organs  as  well 
as  in  the  arteries. 

When  a  large  aneurism  runs  its  course  with 
great  rapidity,  an  opportunity  is  frequently 
afforded  of  observing  a  condition  of  the  vessel 
most  favourable  to  the  production  of  the  dis- 
ease, and  which  therefore  may  be  considered 
as  one  of  its  direct  or  immediate  causes.  The 
vessel  in  this  case,  on  being  slit  up,  exhibits 
its  internal  lining  membrane  less  smooth  and 
polished  than  in  its  natural  state ;  its  colour  is 
changed  to  a  deep  roseate  carmine,  and  it  sepa- 
rates "from  the  subjacent  fibrous  coat  with  com- 
parative facility.  This  latter  structure  is  also 
changed  in  colour,  but  not  to  so  bright  a  red 
as  the  other.  Between  these  coats,  but  more 
closely  attached  to  the  internal,  (for  they  peel 
off  with  it,)  are  numerous  specks  of  a  soft 
steatomatous  material  of  a  white  or  pale  grey 
colour,  presenting,  on  a  superficial  inspection, 
somewhat  of  the  appearance  of  the  calcareous 
deposit  already  spoken  of.  An  artery  in  this 
condition  has  lost  more  or  less  of  its  elastic 
properties;  it  is  distended,  and  its  calibre 
increased  equally  around.  As  the  arteries  are 
always  full,  the  impulse  of  every  new  wave 
of  blood  driven  on  the  greater  quantity  con- 
tained within  the  distended  vessel  increases  its 
apparent  pulsation,  for  it  is  in  the  diastole  or 
expanded  condition  of  the  artery  that  the  pulse 
is  felt.  This  loss  of  elasticity  must  obviously 
weaken  the  vessel,  and  cause  it  to  be  less  re- 
sisting: a  fact  that  can  be  proved  by  expe- 
riment after  death,  when  an  artery  so  circum- 
stanced will  be  found  to  yield  and  tear  under 
a  distending  force  that  would  have  little  effect 
on  it  if  in  health,  and  will  explain  how  an 
apparently  trifling  exertion  may  produce  aneu- 
rism in  one  man,  whilst  numbers  of  others 
exposed  to  similar  or  even  greater  violence 
escape  safe  and  unharmed. 

If  arteritis  can  be  justly  considered  as  an 
immediate  cause  of  aneurism,  it  follows  that 
any  thing  tending  to  produce  this  condition  of 
the  vessel  will  predispose  to  the  disease.  An 
investigation  of  the  natural  history  of  this 
affection  would,  therefore,  prove  equally  useful 
and  interesting,  but  as  yet  a  sufficient  num- 
ber of  facts  have  not  been  collected  from  which 
any  useful  practical  induction  can  be  drawn. 
The  experience  of  an  individual  cannot  be 
sufficient  to  establish  a  fixed  and  general  posi- 
tion, but  may  be  valuable  if  it  induces  others 
to  a  similar  line  of  investigation,  in  order  to  its 
being  verified  or  contradicted ;  and  from  a 
minute  attention  to  the  previous  history  of 
several  cases,  I  have  frequently  been  able  to 
connect  intemperance,  particularly  in  the  use 
of  spirituous  liquors  and  repeated  or  ill-con- 
conducted  courses  of  mercury,  with  the  pro- 


duction of  arteritis.  How  far  these  can  explain 
the  comparative  infrequency  of  the  disease  in 
females  and  its  prevalence  amongst  men  sub- 
ject to  exposure,  and  too  often  of  reckless  and 
dissolute  habits,  must  be  determined  by  future 
observation  ;  but,  in  corroboration  of  the  latter 
part  of  this  opinion,  it  may  be  remarked,  that 
few  old  persons  are  subjected  to  a  course  of 
mercury  that  do  not  perish  shortly  after  by  the 
bursting  of  a  bloodvessel, — of  apoplexy,  or 
haemoptoe  most  frequently. 

When  arteritis  has  proceeded  to  the  extent 
of  producing  these  steatomatous  deposits,  if 
aneurism  is  not  inevitable,  it  is  certainly  very 
likely  to  ensue.  In  some  instances  the  loss  of 
elasticity  is  so  great  as  to  cause  all  the  coats 
of  the  vessel  to  yield  and  become  distended 
into  the  sac  of  a  true  aneurism :  in  others, 
(and  far  more  frequently)  the  process  of  ulce- 
ration  commences,  the  lining  membrane  cover- 
ing one  of  these  spots  first  becoming  soft, 
then  exhibiting  a  distinct  ulcer  which  proceeds 
from  within,  eroding  the  middle  coat  either 
through  its  entire  thickness  to  the  cellular, 
which  is  then  easily  distended  into  the  aneu- 
rismal  sac  ;  or  so  far  as  that  it  shall  be  likely 
to  give  way  and  tear  under  a  trifling  shock, 
even  under  the  impulse  of  the  circulation. 
In  the  pathological  collection  of  the  medical 
school  of  Park-street,  Dublin,  there  are  pre- 
parations exhibiting  these  forms  of  aneurism 
and  the  different  stages  of  dilatation,  of  soft' 
ening,  and  of  ulceration  in  the  most  satisfactory 
manner. 

Circumscribed  false  aneurism.  —  When  a 
person  experiences  a  sensation  as  if  something 
had  given  way  or  been  torn  within  his  limb, 
or  even  without  such  previous  warning,  per- 
ceives a  small  hard,  pulsating  tumour  situated 
somewhere  immediately  on  the  course  of  a  large 
or  leading  artery,  it  is  to  be  suspected  that  an 
aneurism  has  formed.  And'  this  suspicion  is 
confirmed,  if  the  tumour  becomes  larger  or 
smaller,  according  to  the  diastole  or  systole 
of  the  artery,  or  is  diminished  by  pressure,  or 
almost  disappears  if  the  patient  should  happen 
to  faint.  If  pressure  be  applied  on  the  trunk 
of  the  artery  between  the  tumour  and  the 
heart,  its  pulsation  ceases,  its  size  is  sensibly 
diminished,  and  it  becomes  soft  and  flaccid; 
if  on  the  farther  or  distal  side  of  the  tumour, 
its  size  is  increased,  and  its  throbbing  rendered 
far  more  evident.  The  pulsation  is  said  to 
become  more  faint  in  proportion  to  the  growth 
of  the  tumour,  and  this,  though  generally  true, 
is  not  so  universally,  for  this  symptom  will 
presently  be  found  to  be  influenced  by  a  num- 
ber of  circumstances,  such  as  the  blood  within 
the  sac  being  fluid  or  coagulated,  the  situation 
and  depth  of  the  tumour  within  the  limb,  and 
the  coverings  of  fascia  it  may  possess.  In 
most  instances  there  is  a  peculiar  whizzing 
sound,  plainly  perceptible  on  applying  the  ear 
or  a  stethoscope  to  the  tumour,  termed  by  the 
French  the  "  bruit  de  soufflet;"  but  its  pre- 
sence or  absence  is  by  no  means  pathogno- 
monic,  for  it  may  be  artificially  produced  by 
pressure  on  the  trunk  of  any  large  artery. 

On    examining    a   circumscribed   aneurism 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


after  death  or  the  removal  of  the  limb,  the 
artery  should,  if  possible,  be  always  slit  up 
on  the  side  opposite  to  that  from  which  the 
tumour  springs.  The  appearances  of  inflam- 
mation will  probably  depend  on  whether  the 
;HU  urism  be  recent  or  of  lung  standing,  and 
obviously  on  whether  it  has  been  the  result  of 
accident  or  disease.  Also,  if  it  be  recent,  the 
aperture  leading  into  the  sac  is  generally  well 
defined,  circular,  and  circumscribed,  its  edges 
remarkably  thin  and  fine :  if,  on  the  contrary, 
it  is  old,  the  aperture  is  large,  smooth,  and  so 
even  as  to  present  an  appearance  as  if  the 
lining  membrane  had  been  prolonged  from  the 
artery  into  the  sac.  On  cutting  into  the  sac 
some  fluid  blood  is  usually  found,  and  always 
a  quantity  in  a  state  of  coagulation.  Besides, 
there  is  always  more  or  less  of  fibrine,  the 
remains  of  former  coagula  deposited  in  irre- 
gular lamina?,  and  varying  in  colour  from  a 
pale  red  or  grey.  The  most  external  layers 
are  closely  fastened  to  the  internal  wall  of  the 
sac  by  means  of  large  depositions  of  flaky 
lymph,  from  which,  however,  they  can  be 
separated  by  careful  washing  or  maceration. 
This  lymph  thickens  the  walls  of  the  sac,  and 
imparts  to  them  considerable  firmness  and 
resistance.  The  sac,  itself,  is  most  generally 
of  an  oval  form,  but  to  this  there  are  some 
exceptions,  amongst  which  the  occasional  oc- 
currence of  a  dissecting  aneurism  is  the  most 
curious.  This  happens  when  the  internal  and 
middle  coats  having  ulcerated  or  given  way, 
the  blood  insinuates  itself  between  the  fibrous 
and  cellular  coats,  detaching  them  from  each 
other  to  a  considerable  extent,  whence  the  dis- 
ease has  derived  its  name.*  Such  is  an  outline 
of  the  appearances  on  dissection,  but  they  will 
avail  little  in  explaining  the  nature  of  aneu- 
rism, unless  combined  and  compared  with  the 
phenomena  of  the  disease  during  life. 

And,  in  the  first  instance,  it  must  be  recol- 
lected that  the  tumour  is  pulsatile,  a  quality 
that  proves  the  entrance  of  a  quantity  of  fluid 
blood,  arid  its  return  back  again  into  the  artery 
by  the  resistance  or  reaction  of  the  sac.  It  was 
this  circumstance  that  principally  led  Fer- 
nelius  to  believe  and  to  teach  that  aneurism 
consisted  in  a  dilatation  of  all  the  coats  of  the 
artery,  inasmuch  as  he  could  not  understand 
how  pulsation  occurred  if  the  tumour  did  not 
possess  an  elastic  covering,  and  moreover 
imagined  that  if  the  blood  was  driven  into  a 
sac  otherwise  constituted,  it  must  of  neces- 
sity remain  there  and  become  coagulated. 
It  is,  however,  unnecessary  now  to  discuss  the 
question  as  to  whether  the  sac  of  an  aneurism 
possesses  elasticity  or  not,  when  it  is  daily 
observed  that  any  tumour  (an  enlarged  gland 
for  instance)  situated  on  an  artery,  and  re- 
ceiving an  impulse  from  the  heart,  may  com- 
municate the  sensation  of  pulsation,  provided 
the  skin  and  other  elastic  tissues  covering  it 
are  sound.  Nay,  farther,  it  may  be  remarked 
that  the  pulsation  of  an  artery,  even  with  its 
elastic  coat  uninjured,  is  much  more  apparent 

*  See  Dissections  of  Aneurism,  by  John  Shekel- 
ton,  Dub.  Uosp.  Rep.  vol.  iii. 


233 


than  real,  and  when  felt  ab  externo,  is  greatly 
influenced  by  the  skin  and  its  other  coverings. 
It  is  a  fact  too  well  known  to  every  operating 
surgeon  to  be  for  a  moment  controverted,  that 
an  artery  when  exposed  exhibits  nothing  like 
the  force  of  pulsation  that  it  did  before  the 
skin  was  divided  ;  sometimes  it  is  difficult  to 
ascertain  it  satisfactorily  at  all.  The  late  Pro- 
fessor Todd  has  strongly  pointed  out  this 
circumstance  in  his  case  of  axillary  aneurism, 
published  in  the  third  volume  of  the  Dublin 
Hospital  Reports,  where  he  says,  "  For  some 
time  I  could  not  be  convinced  that  the  feebly 
pulsating  vessel,  to  which  the  point  of  my 
finger  was  applied,  was  really  an  artery  of  such 
magnitude  as  the  subclavian  ;"  and  similar 
observations  could  be  adduced,  if  necessary, 
from  other  sources. 

It  is  of  little  consequence,  then,  whether  the 
aneurismal  sac  possesses  an  elastic  covering- 
proper  to  itself  or  not,  the  resistance  of  the 
external  structures  being  sufficient  to  explain 
the  phenomenon  of  pulsation,  and  the  impor- 
tance of  the  integrity  of  these  structures  in  the 
progress  and  termination  of  the  case  is  ex- 
tremely interesting.  If  even  a  small  quantity 
of  blood  was  thrown  at  each  pulsation  of  the 
heart  into  a  yielding,  unresisting  bag,  it  must 
of  necessity  remain  there,  and  in  a  very  short 
space  of  time  the  accumulation  would  be 
enormous;  but  if  there  is  a  re-acting  force 
capable  of  returning  a  portion  of  this  blood 
and  restoring  it  to  the  circulation,  the  accumula- 
tion and  consequent  growth  of  the  tumour  will 
be  measured  by  the  quantity  of  blood  thus  left 
behind.  The  volume  of  blood  sent  into  an 
aneurismal  sac  must  be  proportioned  to  the 
aperture  through  which  it  has  to  pass,  while 
the  actual  quantity  lost  must  depend  not  so 
much  on  this  as  on  the  non-resistance  of  it  and 
its  coverings,  and  their  incapability  of  return- 
ing the  fluid  back  into  the  circulation.  Hence 
the  growth  of  external  aneurisms  is  in  general 
rapid  or  slow  according  as  they  have  existed  a 
greater  or  less  length  of  time ;  for  in  old  aneu- 
risms the  aperture  into  the  sac  is  generally 
large,  and  the  elasticity  of  the  external  coverings 
is  weakened  by  over-distension. 

The  pathology  of  aneurism  arranges  itself 
under  two  distinct  orders,  one  having  relation 
to  the  open  and  bleeding  artery,  the  other  con- 
sequent on  the  haemorrhage  being  internal. 
This  latter  circumstance  is  interesting  to  the 
surgeon,  because  the  presence  of  the  blood  in  the 
limb,  the  position  it  occupies,  and  the  pressure 
exercised  by  it  on  the  adjacent  structures  and 
organs,  very  often  form  the  most  prominent  and 
important  features  of  the  disease,  and  nearly 
as  frequently  cause  the  destruction  of  the  patient 
as  the  bursting  and  bleeding  of  the  tumour. 
But  the  consideration  of  this  part  of  the  sub- 
ject does  not  immediately  belong  to  the  patho- 
logy of  the  arterial  system,  to  which  these  re- 
marks are  more  particularly  directed.  To  re- 
turn, then,  to  the  open  or  ruptured  artery.  The 
condition  of  the  vessel  is  scarcely  different 
from  that  of  one  wounded  by  a  knife.  It  is  a 
bleeding  artery,  and  the  same  principle  that  is 
applicable  to  haemorrhage  under  any  other 


234 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


circumstances  is  also  available  here,  for  if  a 
wound  of  this  species  of  vessel  cannot  heal 
whilst  its  calibre  remains  open,  neither  can  an 
aneurism  be  cured  until  the  artery  from  which 
it  springs  is  completely  obliterated  at  the  spot 
where  the  aperture  into  the  sac  exists.  The 
complete  closure  of  the  vessel  is  to  be  accom- 
plished by  placing  its  opposite  walls  in  contact 
and  under  the  influence  of  such  pressure  as 
will  occasion  inflammation  and  the  effusion  of 
coagulating  lymph, — a  pressure  that  can  be 
applied  either  ab  externo  by  means  of  com- 
press and  bandage,  or  from  within,  by  placing 
the  blood  in  the  sac  in  a  condition  that  will 
admit  of  its  perfect  and  complete  coagulation. 

Pressure  on  the  tumour,  if  it  could  be  ex- 
actly applied  and  firmly  maintained,  ought  to 
succeed,  and,  in  truth,  has  often  been  success- 
ful, particularly  when  the  disease  is  consequent 
on  a  wound;  but  there  are  so  many  difficulties 
to  be  surmounted  and  dangers  to  be  encoun- 
tered in  its  use,  that  few  entertain  much  confi- 
dence in  it,  and  perhaps  it  never  would  be 
resorted  to  but  from  a  dread  of  consecutive 
haemorrhage  after  a  ligature.  A  bandage,  if 
applied  with  sufficient  firmness  to  operate  with 
rapidity,  occasions  such  excruciating  pain  that 
it  can  scarcely  be  endured  ;  and  if  loosely,  it  is 
liable  to  slip  ;  and  if  even  it  does  finally  work  a 
cure,  the  progress  of  the  case  is  so  protracted 
that  many  patients  become  wearied  with  the 
trial.  Again,  the  large  trunks  of  arteries 
throughout  the  extremities  are  generally  accom- 
panied by  nerves  and  veins  in  such  close 
apposition  with  them,  that  a  compress  can 
scarcely  be  applied  to  one  without  interfering 
with  the  other;  and  instances  have  occurred  of 
dreadful  mischief  having  been  occasioned  by 
interruption  of  the  venous  circulation  in  such 
cases,  even  in  the  course  of  one  night.  Finally, 
pressure  has  very  frequently  caused  the  rupture 
of  the  sac,  and  the  aneurism,  from  being  cir- 
cumscribed, has  suddenly  become  diffused ; 
and  if  there  was  no  other  source  of  apprehension 
but  the  possibility  of  this  latter  occurrence,  it 
should  make  a  surgeon  pause  before  he  adopted 
so  hazardous  a  mode  of  treatment. 

Pressure  from  within  is  effected  by  re- 
moving the  impulse  of  the  heart  from  the 
blood  within  the  sac  for  a  sufficient  time  to 
permit  of  the  sac  becoming  perfectly  filled  with 
blood,  and  for  that  blood  to  become  coagulated. 
This  object  will  be  accomplished  by  interrupt- 
ing the  flow  of  blood  under  the  impulse  of  the 
heart  through  the  leading  trunk  of  the  vessel 
for  a  given  time :  in  cases  of  small  aneurisms 
forty-eight  hours  being  sufficient,  but  the  larger 
and  older  requiring  a  longer  period.  A  ligature 
placed  around  the  vessel  between  the  tumour 
and  the  heart  effects  this  purpose ;  but  it  does 
more  than  is  requisite,  for  it  divides  its  in- 
ternal and  middle  coats,  occasions  the  effusion 
of  lymph  and  the  obliteration  of  the  artery 
there,  and  involves  the  risk  of  consecutive 
haemorrhage  afterwards  on  its  final  separation. 
To  avoid  these  inconveniences,  the  presse  artere 
of  Deschamps  and  a  number  of  other  con- 
trivances for  arresting  the  flow  of  blood  through 
an  artery,  and  admitting  of  easy  removal  after 


the  object  has  been  accomplished,  have  been 
proposed  and  tried,  but  success  has  not  been 
so  great  as  to  warrant  their  general  adoption, 
and  the  operation  by  ligature  is  still  very 
generally  preferred.  It  may  be  applied  either 
at  the  cardiac  side  of  the  tumour,  when  it  acts 
in  the  manner  above  stated,  or  between  the 
aneurism  and  the  capillary  circulation,  in  which 
case  the  principle  of  its  operation  is  somewhat 
different. 

In  the  former  instance,  when  a  ligature  is 
applied  to  the  trunk  of  an  artery,  the  supply 
of  blood  to  the  limb  below  it  is  interrupted  for 
a  few  moments;  the  aneurism  loses  its  pulsa- 
tion, and  sinks  and  diminishes  in  size  more  or 
less  according  as  its  contents  had  been  fluid  or 
coagulated.  Soon  the  blood  begins  to  flow 
through  the  collateral  branches,  and  enters  the 
aneurismal  sac  also,  but  it  passes  into  it  slowly 
and  without  impetus,  and  no  part  of  it  is  again 
forced  back  into  the  circulation.  It  coagulates 
and  comes  to  press  upon  and  close  the  ruptured 
vessel,  which  is  soon  obliterated  by  lymph,  and 
in  process  of  time  becomes  degenerated  into 
little  more  than  a  ligamentous  cord.  A  beau- 
tiful illustration  of  this  entire  process  was  seen 
in  Mr.  Crampton's  case*  of  ligature  of  the  com- 
mon iliac  artery.  The  patient  had  two  aneu- 
risms, one  of  very  large  size  at  the  groin,  the 
other  in  the  popliteal  space  of  the  same  limb, 
firmer,  and  of  much  smaller  dimension.  A  liga- 
ture of  catgut  was  placed  round  the  common 
iliac,  which  either  rotted  or  by  some  accident 
became  detached  on  the  sixth  day  :  the  pulsa- 
tion returned  in  the  larger  tumour,  which  soon 
afterwards  burst,  and  the  patient  perished.  The 
sac  of  the  popliteal  aneurism  being  so  much 
smaller  had  time  to  become  perfectly  filled  with 
blood,  which  was  there  coagulated  and  firm. 
The  ligature  had  accomplished  all  that  was 
necessary  for  it,  and  the  cure  would  have 
been  complete  even  although  the  ligature  had 
loosened — whilst  the  opposite  was  the  fact  with 
reference  to  the  larger  tumour. 

Sometimes,  soon  after  the  ligature  has  been 
applied,  pulsation  reappears  in  the  tumour. 
This  must  always  be  considered  as  an  untoward 
circumstance,  but  does  not  necessarily  involve 
the  failure  of  the  operation;  for  it  may  take 
place  under  two  different  conditions  of  the 
parts.  1.  In  aneurisms  of  very  long  standing, 
in  situations  where  there  is  a  free  and  extensive 
collateral  circulation,  probably  increased  by  the 
pressure  of  the  tumour.  In  these  the  pulsation 
does  not  return  for  some  time  after  the  vessel 
has  been  tied,  and  is  never  so  strong  as  before 
the  operation.  It  may  continue  for  several 
days,  but  gradually  diminishes  in  force,  and  at 
last  ceases.  The  progress  of  the  case  then 
resembles  that  of  the  ordinary  forms  of  the  dis- 
ease, except  that  in  this  the  cure  is  much 
more  protracted.  Apparently,  such  was  Sir 
A.  Cooper's  first  successful  case  f  of  ligature  of 
the  common  carotid  artery,  as  also  the  case  of 
carotid  aneurism  published  in  the  fifth  volume 
of  the  Dublin  Hospital  Reports.}  It  is  not  un- 

*  Medico-Chirurg.  Transactions,  vol.  xvi. 
t  Medico-Chirurg.  Transactions,  vol.  i. 
t  Page  208. 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


235 


likely  that  Mr.  Turner's  case  of  aneurism  in 
the  fore-arm,  in  which  he  secured  both  radial 
and  ulnar  arteries,  was  of  a  similar  description 
also.  2.  Where  by  an  irregular  distribution 
there  exist  two  trunks  in  the  limb,  both  con- 
veying blood  to  the  aneurismal  tumour.  Sir  C. 
Bell  had  a  case  of  popliteal  aneurism  in  the 
Middlesex  Hospital,  in  which,  just  below  the 
origin  of  the  profunda,  the  femoral  artery 
divided  into  two  branches  of  nearly  equal  size, 
which  ran  parallel  to  each  other  until  they 
arrived  at  the  spot  where  the  artery  perforates 
the  tendon  of  the  triceps  muscle,  and  there  they 
united  again.  Only  one  of  these  was  tied,  and 
although  the  pulsation  in  the  tumour  ceased 
for  a  moment,  yet  it  soon  returned,  and  never 
disappeared  until  the  patient's  death,  which 
happened  a  few  days  afterwards,  from  erysipelas. 
A  preparation  of  a  similar  distribution  is  pre- 
served in  the  Museum  of  the  Royal  College  of 
Surgeons  in  Dublin;*  and  it  is  quite  clear  that 
where  such  exists  in  an  aneurismatic  limb,  the 
securing  of  one  of  the  trunks  could  produce  no 
benefit. 

It  has  been  already  stated  that  one  of  the 
effects  of  the  ligature  on  an  artery  is  the  eventual 
obliteration  of  the  entire  calibre  of  the  vessel 
between  it  and  the  nearest  collateral  branch  at 
each  side,  and,  therefore,  it  might  be  supposed 
that  if  it  be  tied  immediately  close  beyond  an 
aneurismal  sac  in  such  wise  that  no  branch 
shall  intervene  between  the  cord  and  it,  the 
whole  of  the  canal  to  the  next  branch,  in- 
cluding the  spot  where  the  rupture  had  taken 
place,  ought  to  become  obliterated,  and  the 
aneurism  thus  be  cured.  This  is  the  principle 
that  led  to  the  performance  of  the  operation  of 
tying  the  artery  at  the  distal  side  of  the  aneu- 
rism. It  was  (I  believe)  originally  proposed  by 
Delpech,  and  put  in  practice  by  Desault,  but 
the  termination  of  the  case  gave  little  en- 
couragement for  future  trials,  and  it  fell  into 
disuse  until  of  late  years,  when  it  has  again  been 
tried  in  England,  and  still  subsequently  by 
Mott,  in  New  York,  but  not  with  a  success  to 
justify  its  general  adoption.  There  is  but  one 
artery  in  the  body  (the  common  carotid)  so 
circumstanced  as  to  answer  the  design  of  the 
operation  ;  and  even  in  this,  if  the  smallest  and 
most  trifling  branch  happened  to  intervene  be- 
tween the  aneurism  and  the  ligature,  it  must 
defeat  the  principle  of  the  operation  altogether, 
and  perhaps  tend  to  aggravate  the  disease. 

True  aneurism. — Two  different  pathological 
conditions  of  an  artery  have  been  regarded  as 
constituting  this  disease ;  one  in  which  the 
entire  circumference  of  the  vessel  is  distended, 
forming  a  tumour  of  an  oval  shape,  pulsating 
strongly  during  life,  and  not  containing  coagu- 
lated blood  :  the  other  is  where  all  the  coats  of 
an  artery  at  one  particular  spot  are  dilated  in 
such  wise  as  to  form  a  sac  springing  from  the 
side  of  the  vessel,  and  containing  blood  with- 
drawn from  the  circulation,  and  in  a  state  of 
coagulation.  Perhaps  it  would  be  more  cor- 
rect to  regard  the  former  of  these  as  a  state  of 

There  is  a  similar  preparation  in  the  Museum 
of  St.  Bartholomew's  Hospital. — Eu. 


vessel  predisposing  to  the  formation  of  a  false 
aneurism,  whilst  the  latter,  presenting  during  life 
the  same  phenomena,  and  curable  on  the  same 
principles  that  have  been  already  laid  down, 
must  be  considered  as  offering  truly  a  specimen 
of  the  disease. 

When  in  consequence  of  arteritis,  or  from 
any  other  cause,  the  elasticity  of  the  arterial 
structure  becomes  impaired  or  weakened,  a 
dilatation  of  the  vessel  at  the  spot  so  debilitated 
ought  to  be  the  result ;  and  this  probably  takes 
place  in  all  arteries  previous  to  the  formation 
of  idiopathic  aneurism.  But  the  circumstances 
that  determine  an  artery  to  become  dilated 
rather  than  to  ulcerate  are  very  obscure,  for 
the  same  morbid  appearances  in  the  vessel  are 
observed  to  precede  both.  In  the  eleventh 
number  of  the  Dublin  Journal  of  Medical 
Science  there  is  an  account  of  two  cases  of 
internal  aneurism,  one  formed  by  ulceration  of 
the  internal  and  middle  coats  of  the  artery, 
which  burst  into  the  oesophagus;  the  other, 
evidently  by  dilatation,  which  destroyed  the 
patient  by  pressure  on  the  trachea :  and  in 
both  the  aorta  exhibited  the  same  appearances 
of  inflammation  and  steatomatous  deposit  be- 
neath the  lining  membrane.  The  preparations 
are  preserved  in  the  collection  of  the  school  in 
Park-street,  and  as  showing  this  pathological 
fact  are  extremely  satisfactory.  Again,  it  is 
not  easy  to  say  what  dilatations  should  be  con- 
sidered aneurismal  or  not.  The  aorta,  in  a  great 
proportion  of  subjects  above  the  age  of  forty, 
is  dilated  ;  yet  such  dilatation  is  not  regarded 
as  an  aneurism.  Other  arteries  present  a  similar 
appearance  occasionally;  and  a  case  occurred 
not  very  long  since  in  the  Meath  Hospital,  in 
which  all  the  arteries  of  the  inferior  extremities 
in  an  aged  man  were  dilated  to  more  than 
twice  their  natural  calibre.  These  vessels  were 
found  after  death  filled  with  coagulated  blood, 
yet  as  the  fluid  seemed  to  circulate  through 
them  during  life,  and  the  patient  never  ex- 
perienced any  inconvenience,  it  is  difficult  to 
admit  them  as  specimens  of  true  aneurism. 
On  the  other  hand,  nearly  at  the  same  time,  a 
man  died  in  another  hospital  who  for  years 
had  a  small  aneurism  of  the  femoral  artery, 
with  every  observable  symptom  of  the  disease 
except  that  the  growth  of  the  tumour  was  un- 
usually slow ;  and  on  dissection  this  appeared 
to  have  been  a  species  of  true  aneurism,  caused 
by  an  equal  dilatation  of  the  entire  circum- 
ference of  the  vessel,  and  did  not  contain  coa- 
gulated blood.  It  would  seem,  then,  impos- 
sible to  pronounce  during  life  on  the  real 
nature  of  an  aneurismal  tumour,  nor  is  it  always 
easy  to  demonstrate  it  after  death. 

In  most  instances  of  aneurism,  particularly 
those  of  long  standing,  the  edges  of  the  aperture 
into  the  sac  are  smooth  and  even,  and  the  lining 
membrane  seems  to  be  prolonged  into  it.  The 
internal  wall  of  the  sac  is  so  thickened,  and  all 
the  parts  so  matted  together  and  confused  by 
depositions  of  lymph  and  fibrine,  that  the 
appearances  altogether  become  so  deceptive  as 
almost  to  countenance  the  old  opinion  as  to  the 
pathology  of  the  disease.  Professor  Scarpa, 
who  principally  opposed  the  doctrine  of  aneu- 


236 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


rism  by  dilatation,  was  obliged  to  support  his 
opinions  more  by  argument  than  by  facts  de- 
monstrable by  dissection  ;  and  although  later  in- 
vestigations, particularly  those  of  Mr.  Hodgson 
and  Mr.  Guthrie,  have  satisfactorily  proved  the 
occasional  existence  of  both  true  and  false 
aneurism,  yet  it  must  be  a  favourable  case  and 
patient  examination  that  will  enable  the  morbid 
anatomist  to  exhibit  its  nature  and  structure 
without  possibility  of  error.  When  cases  of 
inflamed  or  diseased  artery  are  seen,  compli- 
cated with  aneurism,  and  the  same  depositions 
are  observed  in  the  artery  and  in  the  sac,  it 
proves  beyond  doubt  the  identity  of  structure 
in  both.  Thus,  if  an  aorta  be  found  studded 
over  with  specks  of  a  soft  steatomatous  deposit 
situated  between  its  internal  and  middle  coats, 
and  if  on  one  side  of  it  an  aneurism  is  placed, 
in  the  sac  of  which,  throughout  its  entire  ex- 
tent, the  same  appearances  and  the  same  de- 
posit are  observed,  it  follows  that  the  same 
structures  must  exist  in  both,  and  that  one  is 
a  prolongation  of  the  other.  One  of  the  cases 
already  noticed  as  being  a  true  aneurism,  that 
destroyed  the  patient  by  pressure  on  the  trachea, 
exhibited  such  evidence  of  its  nature :  and  a 
similar  one,  but  still  more  satisfactory,  occurred 
in  the  person  of  a  gentleman,  who  died  some 
years  since.  This  patient  had  laboured  under 
some  anomalous  cerebral  symptoms,  and  on 
inspecting  the  brain  a  small  aneurismal  tumour 
was  seen  at  the  bifurcation  of  the  basilar  artery, 
in  the  sac  of  which  were  found  the  same  kind 
of  earthy  depositions  that  pervaded  all  the 
arteries  of  the  body — the  same  so  generally 
observed  in  the  arteries  of  aged  persons.  These 
examples  are  sufficient  to  prove  that  aneurism 
by  dilatation  may  exist,  and  perhaps  its  occur- 
rence in  the  aorta  and  larger  vessels  is  more 
frequent  than  has  been  supposed. 

During  the  past  spring  two  opportunities 
occurred  of  examining  into  the  nature  and 
condition  of  aneurism,  both  in  its  early  stage 
and  long  after  it  had  been  apparently  cured  by 
operation.  They  were,  probably,  both  ex- 
amples of  what  has  been  termed  true  aneu- 
rism, although  unquestionably  all  the  coats  of 
the  artery  were  not  engaged  :  and  as  the  mor- 
bid appearances  have  not  been  hitherto  de- 
scribed, it  may  be  useful  to  take  notice  of 
them  here. 

A  man  was  admitted  into  the  Meath  Hos- 
pital, with  popliteal  aneurism  in  each  ham  : 
one  of  these  had  existed  for  several  weeks  ; 
the  other  was  of  very  recent  occurrence.  The 
limb  in  which  the  older  and  larger  one  was 
situated  was  first  made  the  subject  of  opera- 
tion, the  femoral  artery  was  tied,  but  the 
patient  died  on  the  sixteenth  day  afterwards, 
of  venous  inflammation,  the  ligature  on  the 
vessel  still  remaining  firm  and  undetached. 
On  examining  the  aneurismal  tumour  exter- 
nally it  appeared  of  an  oval  shape,  and  to  have 
been  formed  by  the  gradual  expansion  of  all 
the  coats  of  the  vessel.  On  being  cut  into, 
however,  it  was  found  that  the  lining  mem- 
brane was  wanting  throughout  the  entire  extent 
of  the  sac,  the  edge  of  it  terminating  sharply 
and  abruptly,  above  and  below,  at  the  junc- 


tions of  the  tumour  with  the  more  healthy 
parts  of  the  vessel,  and  being  as  accurately 
defined  as  if  made  by  a  careful  dissection. 
The  fibrous  coat  was. evidently  continued  into 
the  tumour,  which  seemed  to  be  formed  of  an 
expansion  of  it  and  the  cellular.  It  was, 
moreover,  otherwise  diseased,  being  thickened, 
greatly  softened  and  thrown  into  irregalar  rugae 
or  folds,  the  interstices  between  which  were 
filled  with  coagula  of  lymph  or  fibrine.  As 
the  sac  of  this  aneurism  was  in  a  state  of  sup- 
puration, the  deficiency  of  the  lining  mem- 
brane was  attributed  to  that  circumstance  until 
the  other  aneurism  came  to  be  examined  when 
the  same  appearances  were  observed.  The 
second  tumour  was  not  so  large  as  a  walnut 
and  evidently  formed  by  the  gradual  expan- 
sion of  the  fibrous  coat,  for  the  abrupt  ter- 
minations of  the  lining  membrane  at  the 
healthy  extremities  of  the  artery  were  still  more 
exactly  defined. 

The  other  case  is  even  more  interesting,  be- 
cause it  exhibits  a  cure  of  aneurism  after 
operation  in  a  manner  that  has  not  been  de- 
scribed, the  principle  of  which  it  is  not  easy 
to  understand.  A  man  was  operated  on  by 
Mr.  Collis,  in  the  Meath  Hospital  for  popliteal 
aneurism  on  the  22d  of  January,  1831.  The 
ligature  came  away  on  the  seventeenth  day,  the 
tumour  diminished  ;  in  short,  every  thing  went 
on  well  and  the  patient  left  the  hospital  per- 
fectly cured.  So  far  as  the  aneurism  was  con- 
cerned, he  remained  healthy  and  free  from 
inconvenience  until  his  death,  which  hap- 
pened in  March  1835,  from  fever,  and  such  an 
opportunity  for  pathological  inquiry  was  not 
neglected.  The  tumour  which  had  been  origi- 
nally of  the  size  of  a  turkey's  egg,  was  found 
to  have  diminished  to  little  more  than  that  of  a 
walnut :  externally  it  felt  hard  and  as  if  com- 
pletely solidified  :  on  being  cut  into,  however, 
neither  artery  nor  sac  was  obliterated,  the  latter 
being  occupied  by  a  coagulum  of  a  deep  red 
colour,  through  the  centre  of  which  was  a  canal 
of  a  sufficient  size  to  allow  the  blood  from  the 
portion  of  the  artery  above  the  tumour  to  flow 
freely  into  that  below  it.  It  seemed  as  if  the 
current  of  blood  through  the  sac  had  never 
been  interrupted,  the  only  effect  of  the  former 
ligature  having  been  the  removal  of  the  im- 
pulse of  the  heart  from  it.  This  aneurism 
appeared  to  have  been  a  true  one,  so  far  as  the 
fibrous  and  cellular  coats  were  concerned,  but 
the  fact  could  not  be  so  satisfactorily  demon- 
strated as  to  admit  of  no  dispute ;  however, 
the  absence  of  the  lining  membrane  and  its 
sharp  and  abrupt  terminations  at  the  healthy 
portions  of  the  vessel  were  sufficiently  ob- 
vious. 

If  it  be  difficult  to  demonstrate  the  nature 
and  constitution  of  the  small  and  recent  aneu- 
rism, it  becomes  impossible  when  the  tumour 
has  attained  to  a  considerable  size.  It  seems 
probable,  however,  that  the  arterial  structures 
will  not  long  endure  this  state  of  unnatural 
distension,  and  they  either  ulcerate  or  tear  in 
their  internal  and  middle  coats.  A  mixed 
aneurism  will  thus  be  formed,  having  its  sac  at 
first  composed  of  all  the  structures  of  the  artery, 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


and  subsequently  in  the  largest  portion  of  its 
circumference,  of  the  cellular  coat  alone.  The 
long  continuance  and  gradual  increase  of  some 
aneurisms,  as  contrasted  with  their  sudden  and 
rapid  growth  afterwards,  have  been  explained 
on  this  supposition. 

Diffused  aneurism. — An  aneurism  is  termed 
diffused  when  the  blood,  removed  from  the 
circulation,  is  not  confined  within  a  pouch  or 
sac,  and  therefore  passes  in  every  direction 
throughout  the  cellular  tissue  of  the  limb. 
This  may  be  occasioned  by  the  rupture  or 
ulceration  of  an  aneurismal  sac,  but  far  more 
frequently  by  some  violence  applied  to  the  artery 
itself  in  such  a  manner  as  to  open  its  cellular 
as  well  as  its  other  coats.  Thus  a  spicula  of  a 
fractured  bone,  or  a  pointed  sequestrum,  in 
coming  from  a  necrosed  limb,  may  produce  the 
disease  ;  but  the  most  common  examples  that 
fall  under  a  surgeon's  observation  are  furnished 
by  awkward  or  ignorant  persons  in  their  at- 
tempts to  perform  the  operation  of  phlebotomy. 
In  the  latter  case  there  is  an  external  wound 
communicating  with  the  injured  vessel,  and 
then  it  also  presents  a  familiar  illustration  of 
traumatic  aneurism. 

When  the  blood  is  thus  diffused  throughout 
the  cellular  tissue,  there  is  always  the  greatest 
danger ;  not  so  much  from  the  loss  of  a  large 
quantity  to  the  circulation  as  from  the  rapidity 
with  which  a  limb  so  circumstanced  runs  into 
a  gangrene, — a  rapidity  so  great  that  the  mor- 
tification either  is  not  or  seems  not  to  be  pre- 
ceded by  inflammation,  and  its  occurrence  is 
often  the  first  notice  a  surgeon  receives  of  the 
extent  and  nature  of  the  accident.  When  the 
injured  artery  lies  deep  and  is  covered  by  a 
dense  and  resisting  fascia  (as  in  the  instance 
of  the  posterior  tibial  artery  being  ruptured  by 
a  blow),  it  may  bleed  for  some  time  without 
affording  any  indication  beyond  the  pain  and 
tension  complained  of  by  the  patient,  and  a 
slight  tumefaction  of  the  limb.  When,  how- 
ever, the  fascia  has  yielded  or  sloughed  and  per- 
mitted a  more  extended  diffusion  of  the  blood, 
the  part  becomes  swollen,  glassy,  and  cedema- 
tous,  pale  if  the  blood  did  not  occupy  the 
cellular  tissue  underneath,  but  of  a  livid  colour, 
like  that  of  a  bruise,  if  it  does.  The  joints 
in  the  neighbourhood  are  kept  flexed,  and  any 
attempt  at  motion  gives  intolerable  pain.  In  a 
very  short  space  of  time  circumscribed  spots 
of  gangrene  appear,  which,  on  separating,  per- 
mit masses  of  very  dark  coagula  to  protrude, 
accompanied  by  an  oozing,  or  perhaps,  a  flow 
of  arterial  blood,  under  which  a  patient  will 
very  soon  sink.  And  it  may  be,  the  real  nature 
of  the  case  has  not  been  suspected  until  this 
blood  has  made  its  appearance.  Doubtless,  if 
a  diffused  aneurism  has  been  occasioned  by  a 
wound,  the  rush  of  blood  at  the  moment,  its 
colour,  and  the  difficulty  of  controlling  the  hae- 
morrhage will  point  out  what  has  happened ; 
or  if  there  had  been  a  circumscribed  aneurism 
that  on  a  sudden  lost  its  defined  character 
while  the  limb  began  to  enlarge  above  and  below 
it,  there  would  be  good  grounds  for  suspicion ; 
but  in  any  other  case  it  is  so  difficult  to  sepa- 
rate the  pain  and  tension  and  the  other  symp- 


237 

toms  from  those  which  might  naturally  super- 
vene on  a  severe  injury,  that  the  appearance  of 
a  tendency  to  gangrene  is  too  often  the  first 
circumstance  to  create  alarm.  There  are  many 
symptoms  in  which  the  diffused  aneurism 
differs  from  the  circumscribed,  that  render 
the  diagnosis  of  the  former  particularly  diffi- 
cult. It  has  been  already  stated  that  the 
"  bruit  de  soufflet"  is,  even  when  present,  not  a 
pathognomonic  symptom,  and  if  the  vessel  lies 
deep  it  is  not  to  be  heard  at  all.  Pulsation  of 
the  tumour,  the  most  satisfactory  symptom  of 
an  aneurism,  is  generally  absent,  and  when 
otherwise,  is  very  weak,  fluctuating,  and  indis- 
tinct. To  those  who  reflect  that  the  effused 
blood  is  thrown  out  amongst  inelastic  and 
unresisting  structures,  that  no  portion  of  it  is 
returned  to  the  circulation,  but  that  it  lies 
a  coagulated  mass  amongst  the  surrounding 
cellular  tissue,  the  absence  of  these  symptoms 
will  not  require  explanation. 

Traumatic  aneurism. — But  if,  as  very  fre- 
quently happens,  the  accident  that  caused  the 
aneurism  has  also  created  an  external  wound 
communicating  with  the  injured  vessel,  and 
permitting  the  escape  of  a  portion  of  the  blood 
through  it,  although  still  a  diffused  aneurism, 
the  leading  circumstances  of  the  case  are 
essentially  altered.  This  is  the  form  of  disease 
termed  by  the  French  traumatic  aneurism, 
the  name  having  reference  not  so  much  to 
the  fact  of  its  having  been  produced  by 
violence,  as  to  the  co-existence  with  it  of  a 
solution  of  continuity  in  the  skin  and  other 
structures  external  to  the  vessel.  Thus,  although 
an  aneurism  may  be  caused  by  the  prick  of  a 
lancet  in  the  bend  of  the  arm,  or  by  a  bayonet- 
wound  in  the  thigh,  yet  if  the  external  wound 
is  healed,  or,  being  unhealed,  if  it  is  so  oblique 
or  devious  that  the  blood  flowing  from  the 
artery  does  not  escape  from  the  limb,  it  may 
not  be  called  traumatic,  whilst  a  common  pop- 
liteal aneurism  that  had  arisen  spontaneously, 
if  it  is  accidentally  opened,  assumes  the  cha- 
racter just  designated.  The  chief  peculiarity 
of  this  case,  then,  is  the  external  wound,  and  if 
it  be  conceded  that  it  is  the  resistance  of  the 
unyielding  structures  that  presses  the  coagu- 
lum  against  the  vessel,  and  thus  accomplishes 
the  cure  of  those  forms  of  aneurism  already 
described,  it  will  be  seen  that  a  material  part 
of  the  process  must  be  deficient,  and,  therefore, 
that  the  principles  applicable  to  the  former 
cannot  be  made  available  here. 

In  order  to  the  proper  understanding  of  this 
part  of  the  subject,  it  will  be  necessary  to  take 
a  familiar  case  for  illustration.  A  person  in 
attempting  to  open  a  vein  in  the  arm  strikes 
his  lancet  into  the  artery,  and  is,  perhaps, 
unconscious  of  the  extent  of  the  mischief  he 
has  occasioned.  The  arm  is  tied  up,  but  it 
swells  and  becomes  intolerably  painful.  When 
the  bandage  is  removed,  the  wound  is  found 
not  to  have  united,  and  a  coagulum  is  pro- 
bably seen  plugging  it  up,  which  loosens  occa- 
sionally and  allows  the  escape  of  a  considerable 
quantity  of  red  and  florid  blood.  In  the 
meantime  the  diffusion  throughout  the  limb 
is  extending  in  every  direction,  and  the  hsemor- 


238 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


rhages  from  the  external  aperture  are  more 
frequent.  If  this  case  is  treated  by  ligature 
at  a  distance  from  the  situation  of  the  aneu- 
rism, although  the  patient  may  appear  relieved 
at  the  moment,  that  relief  is  but  delusive.  The 
blood  may  coagulate,  but  being  unsupported 
by  any  external  resistance,  it  cannot  make  suf- 
ficient pressure  on  the  orifice  of  the  bleeding 
vessel.  Fresh  blood  is  carried  round  by  the 
collateral  circulation,  and  as  it  constantly  oozes 
from  the  punctured  artery,  it  disturbs  the  coagu- 
lum  in  the  neighbourhood,  and  bursts  out  into 
new  and  repeated  haemorrhages  until  the  sur- 
geon is  obliged  to  end  where  he  ought  to  have 
begun,  by  cutting  down  (if  he  has  still  the 
opportunity)  directly  on  the  injured  part  of  the 
vessel,  and  tying  it  above  and  below  the  aper- 
ture. The  great  difference  between  the  trau- 
matic aneurism  and  the  other  forms  of  the  dis- 
ease is,  that  in  it  the  haemorrhage  is  external  as 
well  as  internal,  and  that  the  coagulum  within 
the  limb  being  unsupported  may  press  out- 
wards through  the  wound  more  freely  than 
inwards  upon  the  vessel.  The  coagulum, 
therefore,  is  not  available  in  the  cure,  and 
the  treatment  must  have  reference  to  the 
wounded  artery  alone.  If  the  radial  artery 
was  opened  arid  bleeding  freely  from  the  ex- 
ternal orifice,  few  surgeons  would  think  of 
taking  up  the  brachial  high  in  the  arm,  know- 
ing that  the  inosculating  branches  would  still 
supply  abundance  of  blood  to  the  wound, 
and  although  the  pathology  of  traumatic  aneu- 
rism is  somewhat  different,  inasmuch  as  a 
portion  of  the  blood  lost  still  regains  within 
the  limb,  yet  the  principle  of  treatment  is 
unchanged. 

It  may  be  objected  that  in  very  many  in- 
stances of  traumatic  aneurism  success  has  at- 
tended the  application  of  a  ligature  on  a  dis- 
tant part  of  the  artery  ;  but  every  one  of  these 
cases  will  require  to  be  accurately  examined 
before  the  treatment  here  laid  down  can  be 
impeached.  The  definition  of  traumatic  aneu- 
rism must  be  borne  in  mind,  and  that  it  im- 
plies not  only  the  existence  of  a  wound,  but  of 
one  through  which  coagulated  blood  may  pro- 
trude and  fluid  blood  may  trickle.  The  only 
case  in  which  such  practice  could  succeed  is, 
where,  after  the  ligature  had  been  tied,  a  suffi- 
cient degree  of  pressure  ab  externo  could  be 
maintained  to  lay  the  opposite  sides  of  the 
wounded  artery  together,  and  produce  sufficient 
inflammation  to  procure  its  complete  oblitera- 
tion,— in  short  that  it  shall  effect  that  which 
the  resistance  of  the  skin  and  fascia  and 
other  superincumbent  structures  would  have 
accomplished  in  a  limb  less  injured.  Such 
pressure  as  this  must  occasion  intolerable  suf- 
fering; and  experience  has  proved,  in  nume- 
rous instances,  how  little  reliance  can  be 
placed  on  it. 

Secondary  hemorrhage. — Hitherto  the  ap- 
plication of  a  ligature  has  been  noticed  only 
as  a  curative  process,  its  advantages  have  been 
discussed,  and  the  manner  in  which  it  may  be 
supposed  to  operate  explained ;  but  it  has  been 
also  stated  that  "  the  ligature  is  in  itself  not 
infrequently  a  cause  of  great  and  fearful  mis- 


chief," and  as  the  consideration  of  the  different 
cases  that  might  require  the  operation  has  been 
just  concluded,  perhaps  this  may  be  a  fit  op- 
portunity for  examining  into  the  nature  of  these 
unfavourable  cases.  Secondary  or  consecutive 
haemorrhage  occurs,  as  its  name  implies,  at 
some  period  subsequent  to  the  application  of 
the  ligature,  and  the  blood  flows  from  the  place 
where  the  vessel  has  been  tied.  In  many 
instances  the  patient  has  a  kind  of  presenti- 
ment of  that  which  is  about  to  happen,  and 
becomes  restless,  uneasy,  and  agitated  ;  in 
other  instances  there  is  not  the  slightest  warn- 
ing, and  the  first  notification  of  the  mischief  is 
the  appearance  of  the  dressings  soaked  in  blood. 
In  general  it  has  been  stated  that  it  is  on  the 
separation  of  the  ligature  that  this  bleeding 
takes  place,  but  this  is  not  the  fact,  for  com- 
monly it  happens  whilst  the  cord  is  fixed  and 
firm,  and  three  or  four  days  before  its  fall 
ought  to  be  expected.  The  longer  the  ligature 
remains,  provided  no  nerve  or  fascia  had  been 
included  with  the  vessel,  the  safer  the  patient  is, 
and  it  must  be  rare  to  meet  with  secondary  hae- 
morrhage after  the  cord  has  become  detached  and 
been  quietly  withdrawn.  It  is  remarkable  that  the 
blood  comes  from  the  inferior  portion  of  the 
artery;  it  wells  up  abundantly  from  the  bottom 
of  the  wound,  and  never  flows  with  a  gush  or 
per  saltum  ;  it  is  easily  restrained  by  pressure 
on  the  bleeding  orifice ;  and  if  such  pressure  is 
accurately  applied,  and  can  be  maintained 
during  a  very  few  days,  the  cure  is  permanent, 
and  the  patient  would  be  safe  but  for  a  number 
of  collateral  circumstances,  which,  however 
important  in  the  management  of  the  case,  form, 
properly  speaking,  no  portion  of  the  pathology 
of  arteries. 

Various  causes  have  been  assigned  as  pro- 
ducing secondary  haemorrhage,  the  chief  of  which 
is  the  too  extensive  detachment  of  the  vessel 
from  its  surrounding  connexions  during  the 
operation,  an  opinion  that  I  cannot  think  is  borne 
out  by  observation.  If  it  is  supposed  that  this 
dissection  of  an  artery  is  injurious  by  depriving 
it  of  its  vascularity,  and  diminishing  its  supply 
of  nutrient  blood,  the  result  should  be  analo- 
gous if  not  exactly  like  that  which  takes  place 
when  the  vessel  is  deprived  of  its  cellular  coat 
from  any  other  cause,  that  is,  a  slough  should 
form  on  it,  on  the  separation  of  which  the 
haemorrhage  should  occur  violently  and  with 
a  gush.  An  illustration  of  this  is  familiarly 
observed  in  the  phagedenic  ulceration  of  buboes 
in  the  groin,  where  the  artery  for  a  time  appears 
to  resist  the  destructive  process,  and  lies  de- 
nuded like  a  white  cord  at  the  bottom  of  the 
sore ;  but  one  or  more  black  spots  form  upon  it, 
which  are  really  specks  of  mortification,  on  the 
detachment  of  which  the  bleeding  commences 
with  awful  violence.  Perhaps  consecutive 
haemorrhage  does  occasionally  occur  from  the 
burrowing  of  an  abscess  along  the  coats  of  an 
artery,  an  example  of  which  is  on  record  in 
Mott's  case  of  ligature  of  the  innominata,  in 
which  the  bleeding  occurred  ten  days  after  its 
removal,  was  so  violent  from  the  first  as  to 
be  with  much  difficulty  restrained,  and  de- 
stroyed the  patient  on  the  day  but  one  after- 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


wiirds.  But  it  may  be  observed  that  the  phe- 
nomena attendant  on  these  cases  are  different 
from  those  already  described  as  characteristic 
of  the  common  forms  of  the  accident — that 
they  usually  occur  at  a  later  period,  even  long 
after  the  separation  of  the  ligature  might  have 
inspired  confidence  in  the  result,  and  they  are 
evidently  more  hopeless,  for  neither  pressure 
nor  ligature  can  here  be  of  the  slightest  avail. 
Farther,  to  appeal  to  experience,  the  best  and 
surest  foundation  of  every  scientific  principle, 
is  it  not  a  matter  of  daily  observation  that  this 
much-dreaded  insulation  of  the  artery  can  have 
but  little  effect  on  the  ultimate  termination 
of  the  case,  as  operations  performed  in  this 
respect  in  the  most  bungling  and  clumsy  man- 
ner occasionally  end  well,  whilst  the  utmost 
caution  in  not  exposing  more  of  the  artery  than 
will  barely  permit  the  passage  of  the  ligature 
cannot  ensure  the  patient  from  secondary  hae- 
morrhage ? 

When  the  bleeding  is  occasioned  by  any 
defect  in  the  operation,  such  as  tying  the  cord 
too  loosely,  including  adjacent  structures,  &cc. 
it  usually  appears  so  early  as  from  the  third  to 
the  fifth  day  after  the  operation,  and  there  is 
another  form  of  early  consecutive  haemorrhage 
that  occurs  in  consequence  of  the  artery  itself 
being  inflamed  or  otherwise  diseased  at  the 
time  of  the  operation.  An  example  of  this  is  too 
often  met,  when,  as  a  means  of  controlling  con- 
secutive haemorrhage,  a  fresh  ligature  has  been 
tied  on  the  trunk  somewhere  higher  up  or 
nearer  to  the  heart.  It  has  been  remarked  by 
Dupuytren,  that  an  artery  under  such  circum- 
stances is  in  a  most  unfavourable  condition  for 
an  operation  ;  it  is  surrounded  by  cellular  tissue 
in  a  state  of  inflammation,  in  which  it  par- 
ticipates ;  its  coats  are  rendered  so  brittle  that 
they  break  down  immediately  under  the  liga- 
ture, and  the  haemorrhage  returns  in  a  few 
hours.*  It  is  worthy  of  remark  that  in  this 
case  also  the  bleeding  comes  from  the  orifice 
of  the  vessel  below  the  ligature;  indeed,  in  all 
cases  of  divided  artery,  whether  by  a  cutting 
instrument  or  by  a  cord,  the  remedial  process 
seems  to  be  different  in  the  two  fragments, 
being  far  more  perfect  in  the  upper.  On  this 
point  the  statements  of  Mr.  Guthrie  are  most 
valuable  because  founded  on  extensive  ob- 
servation, and  he  remarks  in  the  case  of  an 
artery,  the  bleeding  from  which  had  ceased  of 
itself,  that  if  it  recurs  it  is  more  likely  to 
proceed  from  the  lower  than  the  upper  portion. 
This  latter  fact  is  the  more  important  as  it  bears 
upon  another  supposed  cause  of  secondary 
haemorrhage,  namely,  the  state  of  tension  in 
which  an  artery  inclosed  in  a  ligature  is  ne- 
cessarily placed. 

Many  years  ago  it  occurred  to  Mr.  Aber- 
nethy  that, "  as  large  arteries  do  not  ulcerate 
when  they  are  tied  upon  the  surface  of  a  stump 
after  amputation,  it  would  be  right  to  tie  them 
in  cases  of  aneurism  as  nearly  as  possible  in 
the  same  manner  and  under  the  same  circum- 
stances." It  is  familiarly  known  that  he  re- 
commended for  this  purpose  the  application 

*  Le9ons  Orales,  torn.  iv.  p.  573. 


239 

of  two  ligatures  with  the  division  of  the  artery 
between  them ;  and  he  argues  that  the  divided 
portions  would  be  like  the  large  vessels  on  the 
surface  of  the  stump  in  possession  of  all  their 
surrounding  connexions,  whilst  they  are  left  in 
a  lax  state  in  consequence  of  their  division. 
But  the  cases  after  all  are  not  analogous,  be- 
cause in  the  stump  there  is  no  inferior  portion 
of  vessel  from  which  it  has  been  seen  the 
chief  cause  of  apprehension  arises — it  has  been 
cut  away,  and  only  the  superior  remains,  from 
which  it  is  rare  to  meet  with  haemorrhage 
under  ordinary  circumstances.  In  Mr.  Aber- 
nethy's  operation  it  is  only  the  upper  division 
of  the  vessel  that  bears  analogy  with  the  artery 
of  the  stump,  and  the  insufficiency  of  the 
removal  of  the  tension  in  preventing  haemor- 
rhage from  the  inferior  is  proved,  first,  by  the 
fact  that  consecutive  haemorrhage  occurs  in 
cases  that  have  been  thus  treated  proportion- 
ally as  often  as  in  others ;  and,  secondly,  by 
Mr.  Guthrie's  observation  that  in  the  case  of 
a  wound  there  is  no  tension :  the  artery  has 
been  fairly  divided,  and  its  surrounding  con- 
nexions are  undisturbed  ;  yet  the  bleeding, 
having  ceased  spontaneously,  or,  in  other  words, 
having  been  controlled  by  the  power  of  nature 
alone,  may  recur,  and  when  it  does  the  blood 
flows  from  the  lower  orifice. 

Others  have  believed  that  the  accidental 
position  of  a  collateral  branch  near  to  the 
ligature  might  be  a  cause  of  consecutive 
haemorrhage  by  interfering  with  the  formation 
of  the  internal  coagulum.  I  have  already 
stated  that  4he  importance  attached  to  this 
coagulum  was  greater  than  it  deserved ;  and  it 
will  be  only  necessary  here  to  add,  that  I  have 
tied  the  common  carotid  artery  within  an 
eighth  of  an  inch  of  its  origin  from  the  inno- 
minata  without  the  slightest  ill  consequence 
from  that  circumstance. 

It  has  been  pretty  generally  believed  that  in 
those  cases  which  have  ended  favourably, a  mild, 
healthy,  and  mitigated  process  of  inflammation 
had  been  established  which  terminated  in  the 
effusion  of  lymph  and  the  obliteration  of  the 
vessel,  whilst  in  the  unfavourable  the  inflam- 
mation was  more  violent  and  ran  into  ulce- 
ration.  Nothing  is  more  familiar  than  to  hear 
of  the  ulceration  of  an  artery  in  connexion 
with  and  as  the  cause  of  secondary  haemor- 
rhage, yet  the  existence  of  such  ulceration  is 
very  questionable.  Arteries  are  not  prone  to 
ulcerate.  It  has  been  shewn.that  in  the  midst 
of  phagedenic  destruction,  the  artery  escapes 
for  a  length  of  time,  and  when  it  is  attacked, 
it  is  rather  by  mortification:  and  the  appear- 
ance of  arteries  traversing  in  safety  the  cavities 
of  tubercular  abscesses  in  the  lungs,  where 
they  have  lain  for  weeks  or  months  bathed  in 
purulent  matter,  should  make  us  hesitate  in 
speaking  so  boldly  of  ulceration  in  these  struc- 
tures. The  fact,  as  observed  on  dissection, 
appears  to  be  quite  otherwise,  and  the  haemor- 
rhage to  be  occasioned  not  by  a  hyper-activity 
of  inflammation  tending  to  ulceration,  but  by 
an  absence  or  failure  of  the  process  altogether. 

As  persons,  the  subjects  of  consecutive  hae- 
morrhage, seldom  die  (at  least  in  this  country) 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


240 

of  actual  loss  of  blood,  it  is  not  easy  to  pro- 
cure a  dissection  which  can  satisfactorily  shew 
the  condition  of  the  vessel  at  the  moment  it 
begins  to  bleed,  and  no  subsequent  examination 
can  be  relied  on,  because  the  pressure  or  other 
means  used  to  stop  the  bleeding  may  in  the 
course  of  a  very  few  days  alter  the  appearances 
completely.  I  have  availed  myself  of  every 
opportunity  that  occurred,  and  state  the  results, 
not  with  the  presumptive  hope  of  being  able 
to  establish  any  general  principle,  but  to  excite 
others  to  inform  themselves  on  every  case  fa- 
vourable to  the  further  prosecution  of  the  in- 
quiry, and,  perhaps,  in  some  respects  to  justify 
the  opinions  I  have  formed.  It  is  worthy  of  re- 
mark, that  secondary  haemorrhage  occurs  much 
more  frequently  in  the  arteries  of  the  lower  than 
of  the  superior  extremities  or  of  the  neck,  and 
all  the  specimens  I  have  examined  were  of  the 
femoral  that  had  been  tied  from  half  an  inch 
to  an  inch  and  half  below  the  profunda.  In 
all,  the  portion  of  the  artery  above  the  ligature 
gave  indications  of  inflammation  extending 
nearly  as  high  as  the  common  iliac ;  the  lining 
membrane  more  or  less  vascular ;  the  portion 
of  the  vessel  between  the  ligature  and  profunda 
of  its  natural  size  or  slightly  diminished ;  its 
cavity  occupied  by  the  remains  of  a  coagu- 
lum.  Above  that  point  the  calibre  of  the 
trunk  was  evidently  increased,  and  the  texture 
of  its  coats  less  resisting.  The  inferior  por- 
tion resembled  a  vessel  simply  cut  across, 
its  calibre  diminished,  its  internal  coat  dis- 
coloured, its  divided  edge  smooth  and  even, 
not  rough,  jagged,  or  irregular,  as  would  pro- 
bably be  the  case  if  it  had  been  the  seat  of 
ulceration. 

When  a  ligature  is  tied  tightly  round  an 
artery,  every  thing  included  within  its  noose 
is  killed,  but  this  is  only  a  very  small  ring  of 
the  cellular  coat,  the  internal  and  middle  being 
as  completely  divided  as  if  it  had  been  done 
with  a  knife.  When  the  absorbents  have  de- 
tached the  connection  of  this  ring  with  the 
remainder  of  the  cellular  coat,  there  is  nothing 
(so  far  as  the  vessel  is  concerned)  to  retain  it 
farther,  nor  is  it  of  use  in  preventing  haemor- 
rhage :  it  might  be  withdrawn,  only  that  being 
entangled  in  lymph  or  granulations  from  the 
adjacent  parts,  such  a  proceeding  would  dis- 
turb the  divided  vessel  before  the  curative 
process  was  complete.  This  process  is  in  some 
instances,  perhaps,  never  attempted  in  the 
inferior  portion,  although  such  a  deviation 
from  the  usual  course  is  probably  not  frequent ; 
when  it  does  happen,  the  cure  is  more  tedious 
and  longer  of  accomplishment,  and  when  inter- 
terrupted  prematurely,  of  course  it  is  from  this 
portion  that  the  blood  is  poured  out. 

Whatever  the  process  is  by  which  the  ex- 
tremities of  the  two  segments  are  closed,  it  is 
certainly  not  the  same  in  both.  This  fact  I 
•was  enabled  to  verify  in  one  of  the  cases  al- 
ready alluded  to, — namely,  that  of  the  man  who 
died  on  the  sixteenth  day  after  the  operation 
for  popliteal  aneurism,  and  whilst  the  ligature 
still  remained  undetached  from  the  artery. 
The  vessel  was  carefully  removed  from  the 
body,  and  on  being  slit  up,  the  lining  mem- 


brane of  the  portion  at  the  cardiac,  side  of  the 
ligature  was  of  a  pale  yellow  cftlour  and  nearly 
of  its  natural  appearance,  with  the  exception 
of  one  or  two  broad  spots  of  a  very  li^ht  pink 
colour.  A  large  coagulum  extended  upwards 
from  the  seat  of  the  ligature,  the  base  of  which 
was  attached  to  the  lymph  situated  there.  The 
ligature  was  still  firm,  but  on  attempting  to 
tear  it  away,  the  lower  portion  of  the  vessel 
easily  separated  from  it,  leaving  it  still  fixed 
firmly  on  the  upper  section :  a  circumstance 
which  explained  a  fact  I  had  frequently  wit- 
nessed, that  of  secondary  haemorrhage  occur- 
ring before  the  final  separation  of  the  cord. 
Below  the  spot  where  it  had  been  tied  the 
vessel  appeared  to  be  of  a  deep  pink  colour 
approaching  to  carmine,  the  seat  of  which 
colouring  matter  was  in  the  cellular  tissue 
between  the  fibrous  and  internal  coats.  This 
cellular  substance  seemed  to  be  hypertrophied 
and  largely  congested  with  blood,  whilst  it 
caused  the  lining  membrane  to  be  thrown  into 
transverse  rugae  or  folds.  On  pulling  off  this 
membrane,  it  was  pale,  transparent,  and  colour- 
less— devoid  of  any  proper  vascularity  :  and 
on  looking  along  the  slit-side  of  the  vessel  the 
fibrous  coat  and  the  internal  membrane  were 
seen  like  white  lines  with  the  congested  cellu- 
lar tissue  between  them.  There  was  not  a 
particle  of  coagulum  either  of  blood  or  lymph 
in  any  portion  of  the  vessels  below  the  liga- 
ture. 

It  may  be  objected  that  in  this  very  dissec- 
tion, the  appearances  would  warrant  a  belief 
that  a  more  active  form  of  inflammation  was 
present  in  the  distal  portion  of  the  vessel, 
because  of  the  deeper  tint  of  colour  and  the 
superior  thickness  of  the  cellular  tissue  there 
observed.  Such,  however,  was  not  the  im- 
pression of  those  who  witnessed  the  dissection. 
There  was  no  result  of  inflammation  visible 
after  seventeen  days,  neither  adhesion,  nor  sup- 
puration, nor  ulceration  :  there  was  merely  a 
congested  condition  of  the  part — a  condition 
not  found  in  other  structures  or  situations  to 
lead  to  any  of  the  usual  products  of  inflam- 
mation. 

An  artery,  the  coats  of  which  have  been 
divided  by  a  ligature,  is  subject  to  the  same 
conditions  as  if  it  had  been  severed  with  a 
knife :  its  cavity  must  be  obliterated  from  the 
wounded  spot  to  the  next  collateral  branch 
above  and  below.  Now,  the  constitutional 
causes  that  can  delay  or  impede  this  oblite- 
ration, if  any,  are  not  sufficiently  known ;  but 
it  is  obvious  that  any  local  interference  may 
(as  in  a  case  of  open  haemorrhage)  prove  sin- 
gularly perilous.  During  the  first  few  days, 
whilst  the  continuity  of  the  cellular  coat  is 
still  unbroken,  there  is  no  cause  for  apprehen- 
sion; but  afterwards,  any  irregularity  of  diet, 
any  excitement  of  the  circulation,  any  unwary 
motion,  any  injudicious  meddling  with  the 
ligature;  in  short,  any  one  circumstance  that 
can  interfere  with  or  disturb  the  operations  of 
nature  within  the  part  before  they  are  perfect 
and  complete,  will  have  a  much  more  intimate 
connexion  with  the  production  of  secondary 
haemorrhage  than  any  of  the  causes  hitherto 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


advanced.  Hence  it  is,  that  the  bleeding 
occurs  some  two  or  three  days  earlier  than  the 
period  at  which  the  ligature  naturally  separates 
and  comes  from  the  wound. 

When  the  bleeding  has  commenced,  it  is  a 
case  of  haemorrhage  from  an  open  wound,  and 
must  be  managed  on  similar  principles,  that  is, 
pressure  to  a  sufficient  extent  must  be  applied 
directly  on  the  orifice  of  the  vessel.  I  have 
never  seen  a  second  ligature  applied  on  the 
mouth  of  the  vessel,  either  in  consequence  of 
the  difficulty  of  finding  the  artery  in  a  wound 
swollen  and  matted  up  with  lymph  and  gra- 
nulations, or  from  an  apprehension  of  the  ex- 
istence of  such  a  diseased  condition  of  its  coats 
as  would  cause  it  again  to  break  down  under 
the  cord.  But  I  have  frequently  witnessed 
the  effective  operation  of  direct  pressure,  par- 
ticularly in  three  cases,  which  occurred  within 
the  last  few  months,  two  of  which  were 
patients  in  the  Meath  Hospital,  and  all  of 
whom  recovered.  In  the  application  of  this 
pressure,  however,  much  caution  is  required. 
It  should  not  be  greater  than  is  absolutely 
necessary  to  command  the  haemorrhage;  it 
ought  to  be  maintained  by  means  of  some  me- 
chanical contrivance,  and  be  independent  of  all 
bandages  which  are  liable  to  stretch,  to  loosen, 
or  to  slip,  and  it  should  be  removed  the  very 
moment  this  can  be  done  with  safety.  If  the 
bleeding  has  been  perfectly  restrained  during 
three  or  four  days,  it  is  probable  it  never  will 
return.  The  sequelae  of  secondary  haemor- 
rhage ought  always  to  have  been  regarded  as 
more  important  and  more  perilous  than  the 
bleeding  itself.  I  have  invariably  found  the 
wound  to  become  the  seat  of  unhealthy  sup- 
puration:  very  frequently  abscesses  form  in 
different  parts  of  the  limb,  and  occasionally 
gangrene  supervenes.  It  is  sometimes  diffi- 
cult to  connect  any  of  these  occurrences  with 
a  lesion  of  any  structure  within  the  limb  ;  but 
too  frequently  the  mischief  can  be  evidently 
traced  to  the  pressure  being  directed  on  the 
vein,  and  being  either  too  forcible  or  too  long 
continued. 

Having  thus,  however  imperfectly,  sketched 
the  pathology  of  the  arterial  system  in  con- 
nexion with  the  use  of  the  ligature,  it  will  be 
necessary  to  revert  to  other  forms  of  disease, 
which  have  hitherto  been  postponed,  in  order 
to  permit  the  introduction  of  the  subject  of 
secondary  haemorrhage,  and  that  the  practical 
arrangement  of  aneurism  and  its  consequences, 
both  fortunate  and  otherwise,  might  be  as  un- 
interrupted as  possible. 

Aneurismal  varix. — In  the  year  1761,  Dr. 
William  Hunter*  directed  the  attention  of  the 
profession  to  a  disease  that  had  not  been  before 
observed,  one  not  indeed  very  formidable  in 
its  consequences,  but  exceedingly  curious  as  to 
its  exciting  cause  and  subsequent  progress. 
When  an  artery  and  vein  lying  in  close  con- 
tact are  transfixed  by  a  cutting  instrument  in 
such  a  manner  that  the  aperture  in  one  shall 
exactly  correspond  with  that  of  the  other ;  and 

*  Medical  Observations  and  Inquiries,  vol.  i. 
and  ii. 

VOL.  i. 


241 

when  subsequent  inflammation  has  so  glued 
and  fastened  these  apertures  together,  that, 
whilst  a  mutual  transmission  of  blood  between 
the  vessels  is  freely  permitted,  not  a  drop  will 
be  allowed  to  escape  in  any  other  direction, 
a  disease  is  formed,  to  which  the  discoverer 
gave  the  name  of  aneurismal  varix.  All  and 
each  of  these  several  conditions  are  absolutely 
indispensable,  and  there  are  so  many  chances 
of  their  not  being  fulfilled  in  a  case  of 
wounded  artery,  that  the  infrequency  of  the 
disease  may  be  easily  explained.  It  does, 
however,  occasionally  occur,  and  for  obvious 
reasons  will  most  generally  be  found  in  the 
arm  as  a  consequence  of  phlebotomy. 

Soon  after  the  infliction  of  the  injury  that 
has  been  the  cause  of  the  disease,  a  small 
tumefaction  is  observed  in  the  vein;  its  ap- 
pearance is  irregular  and  knotted,  but  it  is  soft, 
yielding,  and  disappears  on  pressure.  On 
laying  the  finger  on  it,  a  peculiar  thrilling  sen- 
sation is  perceptible,  and  on  applying  the  ear, 
a  whizzing  noise  is  heard,  very  much  re- 
sembling that  occasioned  by  a  fly  inclosed  in 
a  small  paper  bag.  These  phenomena  dis- 
appear on  either  current  of  blood  being  in- 
terrupted by  pressure  on  the  artery  above  or 
on  the  vein  below :  at  the  same  time  that  the 
tumour  subsides  a  little,  (though  it  soon  regains 
its  original  size)  and  the  peculiar  noise  is  no 
longer  heard.  If  the  disease  is  allowed  to 
advance  uninterruptedly,  the  calibre  of  the 
artery  above  the  point  of  communication  be- 
comes enlarged,  but  it  is  diminished  below :  the 
vein  also  enlarges  chiefly  in  the  direction  of 
the  current  of  its  blood,  rarely  in  the  opposite, 
and  then  but  very  slowly.  Another  interesting 
circumstance  is,  that  the  peculiar  thrill  is 
heard  and  felt  all  over  the  dilated  portion  of 
the  vein,  at  a  distance  from,  as  well  as  in  the 
immediate  neighbourhood  of,  the  point  of 
communication  between  the  two  vessels.  It 
seldom  produces  any  inconvenience  that  can- 
not be  remedied  by  the  use  of  a  moderately 
tight  bandage,  and  if  thus  managed  in  time 
never  requires  a  severer  treatment. 

From  the  circumstance  of  pressure,  either 
on  the  artery  or  vein,  diminishing  the  size  of 
the  tumour  and  removing  the  thrilling  sen- 
sation it  imparted,  it  may  be  fairly  inferred 
that  both  these  phenomena  are  produced  by 
the  meeting  of  the  two  currents  of  blood,  and 
their  mutual  resistance  to  the  escape  of  either 
from  its  proper  vessel.  And  further,  it  is  ob- 
vious that  if  the  disease  should  by  any  chance 
prove  troublesome  or  alarming  to  the  patient, 
its  growth  might  be  checked  and  its  progress 
altogether  stopped  by  permanently  obliterating 
the  canal  of  either  the  artery  above  or  the  vein 
below :  but  no  operation  that  a  surgeon  would 
be  justified  in  undertaking  can  remove  the 
tumour,  inasmuch  as  the  blood  still  will  con- 
tinue to  flow  into  and  through  the  enlarged 
vein.  The  dangers  of  secondary  haemorrhage 
after  an  artery  is  tied,  or  of  venous  inflam- 
mation if  the  other  vessel  is  tampered  with, 
ought  to  inculcate  the  greatest  caution,  and  it 
may  be  easily  understood  why  in  such  cases 
Dr.  Hunter  thought  it  advisable  not  to  interfere. 

B 


242 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


This  disease  must,  in  the  great  majority  of 
instances,  be  the  result  of  accident,  and  its 
probable  situation  has  been  already  pointed  out, 
but  it  is  also  possible  that  it  may  appear  as 
an  idiopathic  affection  without  any  previous 
violence.  Some  years  since  a  young  female 
applied  at  the  Meath  Hospital  as  an  out- 
patient, in  whom  aneurismal  varices  existed 
between  every  artery  and  vein  in  the  body  that 
lay  in  a  state  of  approximation  to  each  other. 
In  the  neck,  in  several  parts  of  the  arms,  the 
thighs,  &c.  the  peculiar  thrill  and  sound  were 
remarkably  distinct  and  plain.  She  did  not 
seem  to  experience  much  uneasiness,  nor  could 
any  probable  exciting  cause  be  assigned  for 
such  a  singular  form  of  disease.  She  had  pre- 
viously suffered  from  syphilis  and  been  sub- 
jected to  irregular  mercurial  treatment,  but  it 
would  be  scarcely  fair  to  assume  as  the  cause 
of  a  solitary  specimen  of  disease  in  one  indi- 
vidual, influences  that  operate  so  very  differ- 
ently on  others. 

Varicose  aneurism. — When  a  vein  and  artery 
communicate  with  each  other  in  a  manner 
similar  to  that  already  described,  excepting  that 
an  aneurismal  sac  formed  of  condensed  cellular 
tissue  and  containing  some  coagulated  blood  is 
interposed  between  their  orifices,  the  disease  is 
termed  a  varicose  aneurism.  As  this  disease  is 
generally  the  result  of  some  accident  in  bleed- 
ing, as  it  occupies  the  same  situation  at  the 
bend  of  the  arm,  and  as  the  sac  in  that  case  never 
attains  to  any  considerable  size,  it  is  difficult 
and  frequently  impossible  to  distinguish  during 
life  between  the  two  affections:  nor  is  the 
diagnosis  of  much  importance,  for  as  the  patho- 
logical changes  in  the  artery  and  vein,  and  the 
phenomena  produced  by  them,  are  exactly  the 
same,  so  will  be  the  rationale  of  the  treatment. 

Some  few  years  since,  a  patient  was  admitted 
into  the  Charitable  Infirmary  with  a  popliteal 
aneurism  of  the  size  of  a  child's  head,  and 
with  all  the  veins  of  the  limb,  particularly  of 
the  thigh,  enormously  distended  so  as  to  appear 
like  ropes  twisted  and  knotted  under  the  in- 
teguments.    In  every  one  of  these  veins  the 
peculiar  thrill  and  sound  of  aneurismal  varix 
could  be  distinctly  perceived.    The  account 
he  gave  of  himself  was  this  :  he  had  a  pulsating 
tumour  in  the  ham  for  fourteen  years  previ- 
ously, which  gradually  increased  to  its  present 
size,  until  the  veins  began  to  swell,  when  the 
large  tumour  became  stationary.      He  expe- 
rienced but  little  inconvenience,  and  said  he 
was  able  to  walk  eleven  or  twelve  miles  a  day. 
;  He  was  frequently  permitted  to  leave  the  hos- 
\  pital,  and  exhibited  himself  to  several  profes- 
;  sional  men  for  money.     As  he  refused  to  sub- 
mit to  any  treatment,  and  indeed  no  operation 
i  held  out  a  prospect  of  much  benefit,  he  was 
|  soon  discharged.     This  man  (I  believe)  still 
Hives,  and  as  he  resides  in  a  distant  part  of  the 
\  country,  perhaps  the  true  pathological  nature 
Jof  a  case   so  very   interesting  may  never  be 
f  ascertained.     Could  it  have  been  that  this  was 
{  originally  a  case  of  popliteal  aneurism  that  had 
burst  into  the  popliteal  vein  ?     The  position  of 
this  vein,  and  its  very  intimate  connexion  with 
the  artery,  cause  it  to -appear  to  be  a  pan  of  the 


sac  of  every  popliteal  aneurism,  and  it  is  not 
difficult  to  conceive  that  the  tumour  might  have 
given  way  in  this  particular  situation,  and  a 
communication  been  thus  established  between 
the  artery  and  vein  through  the  medium  of  the 
aneurismal  sac. 

It  may  not  be  unimportant  to  observe,  that 
rare  as  these  latter  forms  of  disease  are  acknow- 
ledged to  be,  they  are  still  more  so  in  reality 
than  is  generally  imagined.  It  often  happens- 
that  a  congeries  of  knotted  and  contorted  veins 
forms  a  tumour  strongly  resembling  the  aneu- 
rismal varix  in  its  external  characters,  and  im- 
parting similar  sensations  of  thrill  and  sound. 
If  one  of  these  happens  to  occupy  a  situation 
favourable  to  the  production  of  aneurismal  varix,. 
it  might  easily  occasion  a  mistake,  and  perhaps  it 
would  be  very  difficult  to  point  out  a  satisfactory 
diagnostic.  I  have  seen  two  of  these  tumours 
dissected,  which  during  the  lives  of  the  patients 
were  supposed  to  have  been  aneurismal  varices,. 
in  neither  of  which  could  the  slightest  commu- 
nication with  any  neighbouring  artery  be  dis- 
covered. 

•  Aneurism  by  anastomosis. — The  d isease  which 
was  so  named  by  John  Bell,  and  by  him  first 
placed  in  the  class  of  aneurismal  tumours,  has- 
no  title  to  such  a  position,  unless  that  it  forms 
a  reservoir  of  blood,  and  occasionally  exhibits 
the  phenomenon  of  pulsation.  But  it  mate- 
rially differs  in  that  the  blood  contained  within 
it  is  fluid,  is  not  withdrawn  from  the  circulation, 
and  therefore  does  not  coagulate.  The  circum- 
stances, however,  of  these  tumours  being  in- 
creased or  diminished  in  size  by  those  influ- 
ences which  excite  or  depress  the  activity  of 
the  circulation,  and  of  the  leading  trunks  of 
the  vessels  supplying  them  having,  however 
erroneously,  been  made  the  subjects  of  opera- 
tion for  their  cure,  serve  to  connect  them  in 
some  respects  with  the  pathology  of  arteries,  and 
j  ustify  a  passing  notice  of  the  subject  here.  This 
kind  of  tumour  has  also  been  called  the  nsevus 
maternus  or  mother  mark,  because  it  so  often- 
appears  from  birth  or  at  a  very  early  age,  and 
its  shape,  colour,  size,  or  situation  is  explained 
by  the  mother  on  the  supposition  of  some  sub- 
stance having  been  thrown  at  her,  or  from  other 
causes  of  affright.  It  may,  however,  appear 
for  the  first  time  in  more  advanced  life,  in  the 
form  of  a  speck  or  pimple,  which  gradually 
enlarges  until  it  constitutes  a  disease  of  a  most 
important  and  sometimes  dangerous  nature. 

The  external  characters  of  aneurism  by  anas- 
tomosis are  somewhat  varied,  and  have  admitted 
of  its  classification  under  three  forms  apparently 
distinct  from  each  other  :  1.  Where  the  mark 
or  stain  is  merely  cutaneous,  does  not  increase 
in  size,  and  is  never  pulsatile.  These  marks 
may  be  of  different  colours,  sometimes  red, 
sometimes  of  a  brassy  yellow,  or  perhaps  brown ; 
and  as  they  occasion  no  inconvenience  beyond 
the  unsightliness  of  their  size  and  situation, 
they  can  scarcely  be  considered  as  diseases. 
Indeed,  if  the  common  mole  be  admitted  un- 
der this  class  of  naevi,  in  many  instances  it 
seems  to  constitute  a  beauty  rather  than  a  defect. 
2.  Where  the  disease  is  situated  in  both  the 
skin  and  sub-cutaneous  cellular  tissue.  It 


ARTERY,  PATHOLOGICAL  CONDITIONS  OF. 


appears  as  a  patch,  slightly  elevated,  of  a  red 
or  purple  colour,  being  generally  of  a  brighter 
hue  on  the  face  or  breast,  and  darker  on  those 
parts  usually  kept  covered.  The  colour  of  the 
naevus  also  seems  to  depend  on  the  quality  of 
the  blood  with  which  it  is  altogether  or  prin- 
cipally supplied,  as  sometimes  tumours  are  met 
with  which  might  he  termed  venous  aneurisms 
of  this  description,  consisting  evidently  of 
veins  indurated,  knotted,  and  contorted  on 
each  other,  increasing  gradually,  and  never  pul- 
satile; these  frequently  occur  in  different  parts 
of  the  body  of  the  same  individual, and  are  always 
attended  more  or  less  with  pain.  The  arterial 
nan  -us  is,  however,  most  intimately  connected 
with  the  present  subject.  It  sometimes  pre- 
sents an  appearance  as  if  irregularly  granulated; 
more  frequently  is  it  smooth  and  velvety.  The 
deep  stain  possesses  a  sharp  and  circumscribed 
edge,  yet  a  net-work  of  minute  vessels  may  be 
seen  like  an  areola  around  it,  conveying  blood 
to  nourish  the  tumour,  and  therefore  forming 
an  important  part  of  the  diseased  structure. 
The  tumour  is  increased  in  size  and  intensity  of 
colour  by  every  thing  that  accelerates  the  circu- 
lation— by  exercise,  intemperance,  paroxysms 
of  passion,  and  even  by  an  elevation  of  tem- 
perature, and  hence  the  supposed  marks  of 
currants  and  other  fruits  are  said  to  grow  red 
and  ripen  at  the  proper  season.  Its  feel  is 
doughy,  and  communicates  a  sensation  as  if  it 
contained  a  jelly.  It  sinks,  and  is  diminished 
by  pressure  on  its  surface,  but  immediately  the 
pressure  is  removed  it  recovers  its  former  level. 
It  may  be  stationary  for  years,  but  the  contrary 
is  generally  observed ;  its  growth,  however,  is 
always  irregular,  being  more  rapid  at  one  period 
than  another.  3.  The  distinguishing  charac- 
teristic of  the  third  form  of  n&vus  is  its  pulsa- 
tility.  It  beats  synchronously  with  the  heart 
and  arteries.  When  wounded,  blood  of  a 
bright  red  colour  flows  from  it,  often  in  such 
abundance  as  to  occasion  syncope  or  even  more 
dangerous  consequences.  As  it  grows  larger, 
the  skin  gradually  becomes  thin ;  it  bursts  and 
bleeds  ;  masses  of  coagula  lie  upon  its  surface, 
putrefying  and  occasioning  the  most  unsightly 
appearance  and  most  offensive  odour.  This 
is  a  condition  that  cannot  endure  long,  the 
patient  soon  becomes  irritable  and  weak,  and 
falls  a  victim  to  that  irregular,  ill-formed  hectic 
which  is  seen  in  every  disease  accompanied  by 
extensive  haemorrhages.  It  is  manifest  that  the 
distinctions  between  these  latter  forms  of  nacvi 
are  merely  artificial ;  the  second  can  be  made 
to  pulsate  and  to  increase  by  heat  or  intem- 
perance, the  third  can  often  be  restrained  by  cold, 
by  abstinence,  and  other  means  that  debilitate 
the  circulation. 

The  external  appearances,  however,  yield  no 
information  as  to  the  condition'  of  the  parts 
within,  or  the  nature  of  this  newly-formed  struc- 
ture; and  on  this  subject  anatomical  investiga- 
tion affords  but  little  satisfactory  knowledge. 
When  a  nsevus  is  extirpated,  it  seems  to  consist 
of  a  mass  of  cellular  tissue,  collapsed  and 
flaccid,  which  cannot  be  unravelled,  and  seems 
to  bear  no  proportion  in  size  to  that  of  the 


243 

tumour  before  removal.  If  it  be  cut  away 
close  to  its  defined  edge,  and  without  the  ex- 
tirpation of  the  zone  of  small  vessels  already 
described,  the  bleeding  is  frightful,  and  in  very 
young  children  »nay  be  fatal,  evidently  shewing 
thiil  these  vessels  are  not  endowed  with  con- 
tractility, and  are  ;>  diseased  and  a  now  fbroia- 
tion.  If  a  nicvus  is  injected,  it  only  ai'lbrds  a 
swollen  and  unshapely  mass  of  whatever  ma- 
terial had  boon  used,  and  throws  tio  light  what- 
ever on  the  rea'  pathology  of  the  disease.  Here, 
i lion,  in  ihe  absence  of  demonstration,  theory 
and  conjecture  are  permitted,  and  all  that  is 
known,  or  supposed  to  be  known,  is  only  the 
fruit  of  speculation. 

Ficll  supposed  the  tumour  to  consist  of  a 
congeries  of  cells,  into  each  of  which  an  artery 
and  vein  opened;  that  these  cells  increased 
both  in  number  and  in  size,  with  the  growth  of 
the  patient,  until  they  became  immense  reser- 
voirs of  blood  ;  and,  finally,  that  they  became 
so  distended  as  to  burst  and  destroy  life,  as  any 
other  aneurism  would,  by  u  profuse  discharge 
of  blood.  Gut  still  this  explanation  is  defec- 
tive, as  showing  nothing  of  the  nature  of  the 
cells  themselves,  or  why  blood  poured  out  into 
them  should  not  coagulate  as  it  would  in  any 
other  cellular  structure.  It  remained  for  Du- 
pnytren  to  offer  an  ingenious  and  extremely 
probable  hypothesis  relative  to  these  points, 
and  he  conceived  the  aneurism  by  anastomosis 
to  be  a  "  tissu  erectile,"  analogous  to  that 
naturally  found  in  many  parts  of  the  body.* 

In  the  penis  of  man,  and  in  the  clitoris 
and  mamclla  of  woman,  there  is  a  particular 
structure,  capable  of  receiving,  retaining  in  a 
fluid  state,  and  afterwards  returning  a  given 
quantity  of  blood.  These  organs  are  provided 
with  strong  fibrous  sheaths,  that  prevent  their 
distension  beyond  a  certain  size,  and  arc  fur- 
nished with  a  number  of  nerves  that  preside 
over  the  circulation  through  them,  and  deter- 
mine their  conditions  of  erection  and  col- 
lapse. The  abnormal  "  tissu  erectile"  consists 
of  a  cellulated  structure,  in  itself  of  the  same 
or  a  similar  structure,  but  not  being  invested 
by  a  fibrous  sheath  or  capsule,  its  growth  is 
unrestrained,  and  the  size  to  which  it  may 
attain  has  no  limit;  and  as  it  has  not  a  similar 
distribution  of  nerves,  there  is  nothing  to  occa- 
sion either  unwonted  distension  or  collapse,  and 
it  is  left  solely  under  the  influence  of  those 
causes  that  act  upon  the  circulation.  (See 

*  The  late  Mr.  Shekelton  of  Dublin  injected  one 
of  these  tumours  with  wax  from  a  large  artery  in 
its  vicinity,  aud  corroded  away  the  animal  matter 
by  immersing  it  in  a  weak  acid  solution,  by  which 
it  was  shewn  to  consist  of  a  congeries  of  vessels 
arranged  in  a  retiform  manner,  dilated  at  some 
points  and  contracted  at  others.  An  able  and  in- 
teresting paper  was  read  on  this  subject,  and  on 
the  tortuosity  of  arteries  generally,  to  the  medical 
section  of  the  British  Association,  which  lately 
met  at  Dublin.  The  great  attainments  of  its  author 
(Mr.  Adams)  in  pathological  science  lead  us  to 
look,  not  without  some  degree  of  impatience,  for 
the  full  publication  of  the  paper,  of  which  but  an 
imperfect  report  has  appeared  in  the  Dublin  Medical 
Journal  for  September  1U35.— ED. 

R  2 


244 


ARTICULATA. 


ERECTILE  TISSUE.)  Thus  an  aneurism  by 
anastomosis  is  made  to  increase  by  heat,  by 
passion,  or  by  excess  of  any  description,  and 
by  the  removal  of  these,  or  by  the  application 
of  opposite  influences,  its  growth  may  be 
checked,  or  its  pulsation  stopped.  But  when 
once  formed,  it  remains  for  ever,  unless  re- 
moved by  spontaneous  ulceration,  by  adhesive 
inflammation  of  the  cells,  or  by  operation;  for 
although,  if  the  general  circulation  be  depressed, 
that  in  the  tumour  will  be  less  active  also,  yet 
the  structure  is  there  still  unaltered  and  ready 
to  receive  the  blood  and  to  exhibit  all  its 
wonted  phenomena  whenever  the  requisite  sti- 
mulus is  applied. 

BIBLIOGRAPHY.  —  Cowper,    on    ossifications  or 
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Vitteberg,  1723  (Rec.  in  Hallcri  Disp.   ad  Morb. 
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Ueberdie  PulsadergeschwUlste,  8vo.  Getting.  1800. 
Maunoir,  Mem.  surFanevrysme,  8vo.  Genev.  1802. 
Briot,  Sur  les  tumeurs  formes  par  le  Sang  arteriel, 
8vo.    Paris,  1802.       Scarpa,   Sull'anevrysma,   fol. 
Pavia,  1804 ;    Anglice,   by  Wishart,    8vo.    Edinb. 
1806.     Freer,  Obs.  on  aneurism  and  some  diseases 
of  the   arterial  system,  4to.  Birming.  1807.     Jones 
on  hemorrhage,  Lond.  1810.     Pelletan,  Mem.  sur 
les  anevrysmes ;    Clinique   Chirurg.    t.  i.   and   ii. 
8vo.    Paris,   1810.     Hodgson,    on   the   diseases   of 
arteries   and   veins,   8vo.  Lond.  1815;    translated 
into  German,  with  notes,  by  Koberwein  and  Krey- 
sig,  Hanover,  1819,  and  into  French  by  Breschet, 
Paris,  1819;    Ejus,  Engravings  to  illustrate  some 
of    the    diseases   of    arteries,    4to.     Lond.    1815. 
Lucte,  De  depositionibus  cretaceis  intra  cordis  val- 
vularum     arteriarumque     substantiam.      Marburg, 
1815.      Lobstein,    Mem.   sur  les   ossifications    des 
arteres ;  Mem.   de   la   Soc.   des   Sciences,  &c.    de 
Strasbourg,  t.  i.     Shehelion,    Dub.   Hosp.   Reports, 
v.  iii.      Spangenberg,    Ueber  die  Entziindung   der 
arterien,  in  Horn's  Archiv.  1804,  Bd  v.  Meli,  Storia 
d'una    angiotide,    &c.     e    consid.     gener.    intorno 
all'infiammaz.    dei    vasi     sanguiferi,    in    Omodei 


Annali  universal! ,  1821.  Dalbant,  De  Tarterite 
ou  infhiin.  des  arteres,  Theses  de  Paris,  1819. 
Barde,  Observation?,  &c.  inflammation  general, 
des  arteres,  Revue  Med.  Mai  1821.  Montesanto, 
Storia  di  un  arteritide  cronica,  Annali  di  Omodei, 

1825.  Locatelli,      Diss.     de     angioitide,    Paviae, 
1828.     Breschet,   Hist,   de  1'inflam.   des  vaissaux, 
Journ.   de   Progres.     Gendrin,  Hist.  anat.   des  in- 
flammations,   2  torn.    Paris,    1826.       Dezeimerit, 
Memoire,  &c.    Aper9u  rapide  des  decouvertes   en 
anatomic  pathologiqne,  8vo.  Paris,  1829.  *  *  *  * 
Turner,  on  the  sudden  spontaneous  obstruction  of 
the  canals  of  the  larger  arteries,  and  Supplement ; 
Transactions  of  the  Medico-Chirurg.  Soc.  of  Edinb. 
vol.  iii.     Syme,  Case  of  obstruction  of  the  arteries 
from  an  internal  cause  ;  Edinb.   Med.  and   Surg. 
Journ.    vol.    xxix.     1828.     *    *    *    *       Manxoni, 
Consid.  sugli  anevrismi ;  Mem.  della  Societa  Ita- 
liana,  t.  xviii.  Moden.  1820.     Fleischer,  Aneurys- 
matis    complicati    historia,    8vo.    Dorpat.     1822. 
Doring,  Quaedam  circa  aneurysmatumpathologiam, 
8vo.  Berl.  1822.     Lem,  Saggio  sugli  anevrismi  in- 
terni,  8vo.  Venez.  1822.     Casamayor,  Reflex,  sur 
1'anevrysme  spontane,  8vo.    Paris,  1825.     Mayer, 
De   arteriarum    regeneratione,    4to.    Bonn.    1823. 
Sch'onberg,     Sul    ristabilmento   della    circolazione 
nella  legatura,  &c.  dei  tronchi  delle  arterie,  Napoli, 

1826.  Ebel,  De  natura  medicatrice  sicubi  arteriae 
vulneratae   et   ligatae    fuerint,   4to.    Giessae,  1826. 
The  papers  of  Lawrence  and  Trovers  ou  the  ligature 
of  arteries   in  the  4th,   6th,    and  8th  volumes  of 
Med.-Chir.  Trans.     Zhuber,   Neue   Versuchen   an 
Thieren  und  deren  Resultate  uber  die  Wiederer- 
zeugung  der  Arterien,  &c.  Wien.  1827.    Corbin,  Des 
anevrysmes  spontanes  ;   Journ.  Univers.  t.  ii.  1831. 
Manec,  Traite  de  la  ligature  des  arteres,  fol.  Paris, 

1832.  Breschet,  Mem.  sur  les  anevrysmes  in  Mem. 
de   1'Acad.    Roy.   de   Med.  t.  iii.    1833.     Guthrie 
on  the  diseases  and  injuries  of  arteries,  8vo.  Lond. 

1833.  Dupuytren,    Le9ons    orales,    t.    iv.      The 
reader  should   moreover    consult    the    systematic 
works  of  Senac,  Corvisart,  Burns,  Laennec,  Kreysig, 
Bertin,  Hope,  Bouillaud,  and  Otto's   Compend.  .of 
pathological  anatomy,  by  South. 

(W.  H.  Porter.) 

ARTICULATA  (articulus,  a  joint,)  a  pri- 
mary division  of  the  animal  kingdom  founded 
by  Cuvier,*  and  characterized  by  him  as  follows : 
"  Body  jointed  externally,  corresponding  to  the 
divisions  of  the  nervous  system  internally :  a 
very  small  brain  placed  above  the  oesophagus 
gives  off  two  filaments  which  extend  along  the 
abdomen  and  unite  together  from  distance  to 
distance  by  means  of  ganglions,  which  resem- 
ble as  many  small  brains,  from  which  nerves 
are  given  off.  The  muscular  system  is  disposed 
on  the  inside  of  the  rings  or  segments  of  the 
body  so  as  to  separate  and  approximate  these 
segments;  when  there  are  articulated  mem- 
bers, the  muscles  of  these  parts  are  also  placed 
within  the  hard  parts.  The  divisibility  of  the 
body,  and  the  power  which  the  fragments 
possess  of  retaining  a  kind  of  independent 

*This  division  was  virtually  established  by  Cuvier 
in  his  earliest  work,  the  f<  Tableau  Elementaire  de 
1'Histoire  Naturelle  des  Animaux/'  although  it  was 
not  defined  with  that  clearness,  nor  its  characters 
so  fully  developed  as  in  the  Regne  Animal.  In  the 
"  Tableau  Elementaire "  the  second  section  of 
'  white-blooded  animals,'  including  the  Insecta  and 
part  of  the  Vermes  of  Linnaeus,  corresponds  pre- 
cisely with  Lamarck's  division  of  invertebrate 
animals,  which  he  first  denominated  '  Articulosa/ 
(Hist.  Nat.  des  Animaux  sans  Vertebr.  torn.  i.  p, 
454.) 


ARTICULATA. 


245 


vitality  corresponds  to  the  distribution  of  the 
nervous  system  into  as  many  centres  as  there 
are  corporeal  segments."*  With  respect  to  the 
agreement  between  the  number  of  segments  of 
the  body  and  the  ganglions  of  the  nervous  sys- 
tem, it  must  be  observed  that  in  the  higher 
crustaceans,  arachnidans,  and  insects,  the  gan- 
glions, though  originally  as  numerous  as  the 
segments,  subsequently  become  concentrated 
by  progressive  development  into  masses  which 
are  fewer  in  number,  and  that  also  in  some  of  the 
lowest  annelidans,  as  the  leech-tribe,  the  ex- 
ternal segments  are  more  numerous  than  the 
internal  ganglions. 

In  many  of  the  molluscous  class  two  nervous 
cords  proceed  backwards  from  the  supraoaso- 
phageal  ganglion  or  brain,  and  are  afterwards 
brought  into  communication  by  ganglionic 
masses  on  the  ventral  aspect  of  the  body  ;  but 
in  the  Articulata  the  uniting  ganglions  are 
always  confined  to  the  mesial  line  of  the  body, 
are  perfectly  symmetrical  in  their  arrangement, 
and  are  accompanied  by  a  symmetrical  or  bila- 
teral form  of  the  whole  body.  It  is  this  homo- 
gangliate  disposition  of  the  nervous  system 
which  essentially  distinguishes  the  Articulate 
from  the  Molluscous  and  other  divisions  of  the 
Animal  Kingdom,  and  it  is  an  infallible  guide 
to  the  true  affinities  of  the  classes  possessing 
it.  The  Cirripeda  present  a  striking  example 
of  this  fact :  these  animals,  on  account  of  their 
inarticulate  body  enveloped  in  a  fleshy  mantle 
and  protected  by  a  multivalve  shell,  were  for 
a  long  time  classed  with  the  mollusca :  but 
the  views  of  those  naturalists  who  considered 
that  they  had  closer  relations  to  the  Arti- 
culata, although  that  opinion  was  founded  on 
a  knowledge  of  their  nervous  system  only,  has 
since  been  corroborated  by  every  additional 
fact  which  has  been  discovered  respecting 
them.  Latreille,  in  his  "  Families  Naturelles 
du  llegne  Animal,"  first  placed  the  cirripeds  in 
the  Articulate  series,  but  being  guided  by  their 
adult  organization,  and  supposing  that  they 
were  deficient  in  visual  organs,  and  underwent 
no  metamorphosis,  he  joined  them  with  the  an- 
nelidans, to  form  a  division  of  Articulate  ani- 
mals, "  Elminthoida,"  distinct  from  the  "  Con- 
dylopeda"  which  include  the  insects,  arach- 
nidans, and  crustaceans,  or  the  Articulata  with 
jointed  feet.  The  later  researches  of  Mr.  I.  V. 
Thompson  and  Dr.  Burmeisterf  have  proved 
that  in  the  immature  state  the  Cirripeds  un- 


members,  and  as  their  nervous  cords  are  sim- 
ple and  not  brought  into  communication  by  a 
regular  series  of  ganglions,  we  prefer  to  leave 
the  Rotifera  and  Ccelelmintha  with  the  Entozoa 
and  Echinodermata,  as  a  separate  and  higher 
subdivision  of  Cuvier's  Radiata,  and  thus  pre- 
serve the  Articulata  as  a  distinct  and  well  de- 
fined subkingdom,  characterized  by  a  dispersion 
of  the  nervous  system  in  a  series  of  ganglions, 
symmetrically  arranged  and  brought  into  com- 
munication by  a  double  nervous  cord  ;  by  an 
articulate  or  jointed  structure  of  the  body  or  its 
appendages,  by  the  lateral  position  and  hori- 
zontal movements  of  the  jaws,  when  these  are 
present,  and  by  the  presence  of  distinct  respi- 
ratory organs.  The  subdivisions  of  this  sub- 
kingdom  are  not  founded  on  the  modifications 
of  any  single  system,  but  principally  rest  on 
the  conditions  of  the  sanguiferous  and  respira- 
tory organs,  in  connexion  with  exterior  form, 
modes  of  locomotion  and  generation. 

I.  The  Cirripeds,  (cirripedia,  cirripeda,  cir- 
rhopoda) ;    oceanic   animals  called   barnacles 
and   acorn  shells  :  they  are  characterized   by 
their  fixed  condition,   being  either  sessile,  or 
attached    to    foreign  bodies   by   means   of   a 
peduncle;   their  generation  is,  consequently, 
hermaphrodite,  without  the  intercourse  of  se- 
parate individuals,  but  the  male  and  female 
organs  are  distinctly  developed  in  each  animal. 
The  blood  is  colourless  and  is  propelled  by  a 
dorsal  vasiform  heart,  but  the  venous  system  is 
diffused.     The  branchiae  are  internal.     The  cir- 
ripeds undergo  metamorphoses,  but  are  ulti- 
mately inclosed   in   an   inarticulate   defensive 
covering  of  shelly  pieces  varying  in  number, 
form,  and  size. 

II.  The  Annelidans,  (Annelida,  red-blooded 
worms,)  are  always  locomotive;    and,  conse- 
quently, although  hermaphrodites,  they  enjoy  the 
intercourse  of  the  sexes,  and  reciprocally  fecun- 
date each  other.    Their  blood,  which  is  gene- 
rally red,  like  that  of  the  vertebrate  animals, 
circulates  in  a  closed  system  of  arteries  and 
veins,  which   sometimes  has  appended  to  it 
several    well-marked     propulsive    cavities    or 
hearts ;  they  respire  by  means  of  organs  some- 
times developed  externally,  sometimes  remain- 
ing on  the  surface  of  the  integument,  or  lodged 
in  its  interior.     Their  body,  which  is  of  an 
elongated  form,  and  covered  with  a  soft  skin, 
is  always  divided    into   numerous  transverse 


mat  m  me  immature  state  the  Cirripeds  un-     segments,  of  which  the  first,  called  the  head, 
dergo  repeated  metamorphoses  or  moults ;  that     scarcely   differs    from   the   others,  except   by 

the  presence  of  the  mouth  and  of  the  principal 
organs  of  the  senses.  Many  possess  branchije, 
arranged  the  whole  length  of  the  body,  or  situ- 
ated at  the  middle ;  others,  which  for  the  most 
part  inhabit  tubes,  have  the  branchise  collected 
at  the  anterior  part  of  the  body;  in  others, 
again,  the  respiratory  organs  are  in  the  form  of 
internal  air  sacs.  The  annelidans  never  possess 
articulated  limbs,  but  many  have,  instead  thereof, 
stiff  bristles,  or  hooks,  frequently  inclosed  in 
tubular  prolongations  of  the  integument. 

The  other  articulate  classes,  viz.,  insects, 
arachnidans,  and  crustaceans,  differ  from  the 
preceding  classes  in  the  possession  of  arti- 
culated limbs,  terminated  by  claws;  and  in 


they  move  freely  in  the  water  by  means  of 
setiferous  articulated  members,  and  during  this 
period  guide  their  wanderings  by  the  aid  of 
distinctly  developed,  though  simple  eyes. 

Besides  the  cirripeds  the  higher  organized 
infusoria  and  intestinal  worms  have  been 
proposed  by  some  naturalists  to  be  added  to 
the  articulate  division  of  Animals  :  but  as  they 
are  neither  articulated  nor  possess  articulate 

*  See  his  celebrated  memoir,  "  Sur  un  nouveau 
rapprochement  a  etablir  entre  les  classes  qui  com- 
posent  le  regne  animal."  "  Anwiles  du  Museum 
d'Histoire  Naturelle,  4to,  torn.  xix.  p.  73. 

t  Beitnige  zur  Naturgeschichte  tier  Kaukeufuesser, 
4to.  Berlin,  1834. 


246 


ARTICULATION. 


connexion  with  the  superior  powers  of  loco- 
motion afforded  by  these  appendages,  the  sexes 
are  separate,  and  the  organs  of  vision  are 
well  developed,  and  often  highly  complicated. 
Witli  the  exception  of  some  genera,  as  the 
myriapoda,  in  which  the  body  is  divided  into 
a  number  of  nearly  equal  segments,  and  of 
the  arachnida  and  many  crustac<.a,  in  which 
the  head  and  thorax  are  blended  together,  the 
body  of  the  condylupes  of  Latreille  is  divided 
into  three  principal  parts,  viz.,  the  head,  which 
bears  the  antennae,  the  eyes,  and  the  mouth ; 
the  thorax,  which  supports  the  feet  and  the 
wings,  when  the  latter  are  present;  and  the 
abdomen,  which  contains  the  principal  viscera. 

These  segments  present  different  degrees  of 
hardness  in  the  different  classes  of  condylopes, 
being  most  flexible  in  the  arachnidans,  firmer 
in  the  insects,  and  calcareous  in  most  of  the 
crustaceans.  The  origin  of  the  insertions  or 
articulations  of  the  body  which  form  so  marked 
an  external  character  of  these  animals,  is  as 
follows : — 

The  integument  is  composed  of  two  layers  or 
pellicles,  viz.,  the  epidermis  and  the  corium, 
and  is  originally  of  equable  consistence,  and 
presents  an  uninterrupted  continuity,  save  by 
some  slight  transverse  superficial  wrinkles. 
The  epidermis  subsequently  becomes  solidi- 
fied, in  arachnidans  and  insects,  by  the  super- 
addition  of  a  peculiar  substance  termed  chitinc, 
and  in  crustaceans  by  a  calcareous  deposition, 
so  as  to  be  divided  into  bands  or  rings.  As  the 
external  development  proceeds,  these  epidermic 
pieces  are  detached  posteriorly  from  the  inferior 
pellicle,  or  corium ;  and  the  intervals  of  the 
segments  remaining  membranous,  and  preserv- 
ing their  flexibility,  yield  readily  to  the  various 
movements  and  inflections  of  the  body. 

The  1 1  Id  class  of  articulate  animals  or  In- 
sects (Insccla),  are  either  myriapod  or  hexapod. 
Most  of  the  latter  are  furnished  with  wings,  which 
they  acquire  at  a  certain  age,  after  undergoing 
metamorphoses  varying  in  kind  and  degree.  In 
every  state  they  respire  by  tracheae,  or  clastic 
vessels  which  receive  the  air  by  stigmata,  situ- 
ated along  the  sides  of  the  body.  A  dorsal 
vessel  propels  the  circulating  fluid,  which  is 
afterwards  diffused  throughout  the  cellular 
tissue  of  the  body.  They  have  conglomerate  or 
compound  eyes,  and  antennae. 

IV.  The  Arachnidans  (Arachnida,  Spiders, 
Scorpions,  &c.),  are  octopod  and  apterous; 


of  gills,  and  have  no  stigmata,  or  spiracles  on 
the  surface  of  the  skin. 

In  the  Articulate  sub-kingdom,  as  in  the  ver- 
tebrate, there  may  be  traced  one  general  plan 
of  structure  pervading  all  the  classes,  but  with 
such  variations  in  it  as  are,  in  each  case,  de- 
manded by  the  particular  exigencies  of  the 
individual  to  which  it  is  applied;  but  these 
variations  are  of  such  a  nature,  that  a  gradation 
of  complexity  or  perfection  may  be  followed 
through  all  the  organic  systems.  With  regard 
to  locomotion,  we  commence  with  a  class  (the 
Cirripeds)  as  fixed  and  immoveable  as  the 
polypes  and  sponges  of  the  Acrite  sub-king- 
dom ;  and  afterwards  trace  a  series  of  forms 
adapted  first  to  slow  and  tortuous  reptation ; 
next  to  swifter  progression,  as  creeping,  run- 
ning, or  leaping ;  and,  lastly,  to  a  rapid  flight 
through  aerial  space. 

Generation,  in  like  manner,  is  effected,  in  the 
lowest  class,  without  the  intercourse  of  separate 
individuals;  afterwards  by  the  reciprocal  im- 

J)regnation  of  co-equal  hermaphrodites,  and, 
astly,  as  in  the  vertebrate  division,  by  indi- 
viduals of  distinct  sexes. 

The  perfection  of  the  nervous  system  results 
from  the  approximation  of  many  separate  gan- 
glions into  fewer  masses  of  nervous  matter.  The 
organs  of  the  senses  also  augment  in  number 
and  complexity. 

The  Articulata  present,  in  the  organs  of  the 
vital  functions,  as  strongly  marked  differences 
as  are  met  with  in  the  vertebrate  animals. 
With  respect  to  the  sanguiferous  system,  a 
gradation  may  be  traced  from  a  circulation 
in  closed  vessels  to  a  diffused  condition  of 
the  nutritious  fluid  ;  and  a  corresponding  pas- 
sage from  the  articulata  which  respire  by 
means  of  circumscribed  branchiae*  to  those 
in  which  indefinitely  ramified  trachese  carry 
the  air  to  all  the  parts  of  the  body.  The 
amount  of  respiration  thus  produced  occasions 
the  same  effects  here,  as  in  the  Vertebrate 
sub-kingdom,  and  the  Insects  thus  constitute, 
as  it  were,  the  Birds  of  the  Articulate  division 
of  animals. 

(Richard  Owen.) 

ARTICULATION  (in  anatomy),  synony- 
mous with  joint.  (Gr.  aftyov.  Lat.  articulus, 
arthrosis,  junctura.  Fr.  articulation.  Germ. 
Articulation,  Gclctik.  Ital.  articolo). 

The  power  of  motion,  to  an  extent  however 


>»JV-'VJ.|^lV/llk5j       VVV^.Ij         lilt       V^tWJJWVL       C*UU          Cll7LC.l.^U.a    .  J.11C       IH.IVYC1       ^-'1       iUVLlV^Mj      C<  /     Clll    \^ALV^l-ll.    UVSTVW^^ 

they  have  no  antennoe,  and  have  simple  eyes,     limited,  seems  to  be  inseparable  from  our  idea 


Their  circulation  is  effected  by  a  dorsal  vasi- 
form  heart  which  transmits  arterial  branches, 
and  receives  the  returning  blood  from  veins. 
Their  organs  of  respiration  vary,  some  pos- 
sessing true  pulmonary  sacs  which  open  upon 
the  sides  of  the  abdomen,  others  receiving  the 
air  by  trachese,  like  insects.  In  both  cases, 
however,  the  air  is  respired  by  lateral  orifices 
or  true  stigmata. 

V.  The  Crustaceans  (Crustacea)  have  never 
less  than  ten  feet;  they  have  two  compound 
eyes,  and  also  antennae,  which  are  generally 
four  in  number;  their  blood,  which  is  white, 
is  circulated  by  means  of  a  muscular  ventricle 
situated  on  the  back.  They  respire  by  means 


of  an  animal,  and  in  looking  through  the  animal 
series  we  find  none  which  do  not  appear  to  be 
endowed  with  this  power  whether  for  the  pur- 
pose of  progression,  or  simply  of  altering  the  po- 
sition or  condition  of  some  part  of  their  bodies 
with  respect  to  the  others.  The  organic  structure 
which  is  the  immediate  agent  in  this  motive 
power  (the  muscular  fibre),  is  one  and  the  same 
throughout  the  whole  chain  of  animals,  va- 
riously modified  according  to  the  degree  and 
force  of  the  motions  necessary  for  the  particular 
individual.  The  mechanism  by  which  this 
structure  acts  upon  the  different  parts  of  the 
body  varies  considerably,  and  increases  in 
complexity  as  the  forms  of  the  animals  them- 


ARTICULATION. 


247 


selves  become  more  complex.  In  the  lowest 
grade  of  animals  the  structure  is  so  soft  and 
pliant  that  nothing  more  is  required  to  produce 
motion  than  this  contractile  tissue,  which  acts 
in  obedience  to  certain  stimuli.  But  when 
hard  parts  are  superaddcd  to  tlie  structure 
of  the  animal,  we  then  find  a  peculiar  me- 
chanism to  allow  of  the  motion  of  these  hard 
parts  on  each  other  without  the  risk  of  injury. 
It  is  obvious  that  such  motion  could  not  take 
place  were  these  hard  parts  united  in  one  piece. 
Hence  we  find  that  they  are  subdivided  into 
segments,  and  these  segments  are  joined  to 
each  other  through  the  medium  of  some  struc- 
ture more  flexible  than  that  of  the  segments 
themselves,  or  by  an  apparatus  of  such  a  con- 
struction as  to  admit  of  the  motion  of  one 
segment  upon  the  other.  It  is  to  these  join- 
ings of  different  segments  of  an  animal  body 
that  the  term  articulations  or  joints  has  been 
applied. 

An  articulation  may,  therefore,  be  defined  to 
be  the  union  of  any  two  segments  of  an  animal 
body  through  the  intervention  of  a  structure  or 
structures  different  from  both. 

The  most  perfect  and  elaborate  forms  of 
articulations  are  those  which  are  seen  in  ani- 
mals that  possess  a  fully  developed  internal 
bony  skeleton,  and  in  none  may  they  be  studied 
with  more  advantage  than  in  man.  We  propose 
to  treat  of  the  forms  and  structure  of  the  ar- 
ticulations in  man,  and  at  the  same  time  to  in- 
quire what  modes  of  mechanism  are  employed 
for  analogous  purposes  in  the  lower  classes. 
In  the  human  subject  and  in  the  vertebrated  ani- 
mals generally,  we  shall,  indeed,  have  particular 
occasion  to  admire  the  articulations,  as  mira- 
biles  commissuras,  et  ad  stabilitatern  aptas,  et 
ad  artus  finiendos  accommodatas,  et  ad  mo- 
tum  et  ad  omnem  corporis  actionem.* 

It  will  be  observed  that  the  definition  here 
given  of  articulation  is  of  the  most  compre- 
hensive nature.  In  most  instances,  in  man,  two 
parts  articulated  together  are  joined  by  their 
solid  portions,  which  are  never  in  immediate 
apposition  with  each  other,  but  have  some 
elastic  structure  interposed  which  may  or  may 
not  form  a  bond  of  union ;  and  it  is  obvious 
that  the  fact  of  the  intervening  substance  being, 
or  not  being  also  a  bond  of  union  will  greatly  in- 
fluence the  extent  of  motion  of  which  the  joint 
is  capable.  Before  inquiring  into  the  variety 
of  forms  of  joints,  we  shall  first  examine  briefly 
the  various  structures  which  enter  into  their 
composition,  and  which  essentially  contribute 
to  the  perfection  of  their  mechanism. 

These  parts  may  be  enumerated  as  follows, 
and  we  propose  to  observe  the  same  order  in 
treating  of  them:  —  1.  Bone.  2.  Cartilage. 
3.  Fibro-cartilage.  4.  Ligament.  5.  Synovial 
membrane. 

1.  Bone.  —  The  osseous  or  an  analogous 
structure  constitutes  the  fundamental  portion 
of  an  articulation  in  all  the  vertebrated  animals, 
in  the  mollusca,  and  in  some  of  the  articulated 
classes.  In  the  human  subject  and  all  ver- 
tebrated animals  we  find  that  certain  parts  of 

*  Ciccr.  de  Nat.  Deor.  1.  ii.  c.  35. 


the  bones  have  surfaces  marked  upon  them 
in  correspondence  with  similar  surfaces  on 
others  with  which  they  are  connected,  or 
that,  as  in  the  long  bones,  the  extremities 
are  expanded  or  enlarged,  and  present  sur- 
faces which  are  adapted  to  similar  surfaces 
on  contiguous  bones.  In  this  way  are  formed 
the  articular  portions  of  the  bones,  and  we 
observe  that  these  portions  present  considerable 
varieties  in  their  characters  according  to  the 
nature  of  the  articulation  which  they  con- 
tribute to  form.  In  fact,  in  examining  these 
articular  portions  of  the  bones  we  cannot  fail 
to  notice  the  diversity  of  their  form,  so  that 
some  are  adapted  to  each  other  in  such  a 
manner  as  evidently  to  favour  motion,  and 
others  are  so  framed  as  to  limit  and  restrict  it. 
The  articular  surfaces  in  dry  bones  are  ge- 
nerally characterised  by  a  peculiar  smooth- 
ness, indicative  of  the  existence  on  them  of 
a  cartilaginous  incrustation  in  the  recent  con- 
dition. The  expansion  of  the  extremities  of 
the  long  bones  on  which  the  articular  surfaces 
are  formed  is  to  be  attributed  to  the  accu- 
mulation there  of  a  considerable  quantity 
of  the  reticular  texture,  covered  by  a  thin 
lamina  of  compact  tissue,  whereby  a  large 
surface  is  obtained  without  the  inconvenient 
increase  of  weight  which  would  necessarily 
result  did  that  portion  of  the  bone  contain 
compact  tissue  to  any  extent.  In  the  neigh- 
bourhood of  the  articular  portions  of  the  bones 
we  find  certain  eminences,  depressions,  or  rough- 
nesses, which  indicate  the  points  of  attach- 
ment of  those  bonds  of  union  by  which  the 
joints  are  secured  and  strengthened.  In  ge- 
neral it  may  be  observed  that  the  long  bones 
are  articulated  with  each  other  by  joints  which 
possess  a  considerable  extent  of  motion;  the  flat 
bones,  again,  have  articulations  very  limited  in 
their  mobility,  and  this  is  likewise  the  case 
with  the  irregular  bones. 

2.  Cartilage. — Pure  cartilage  enters  into  the 
composition  of  almost  all  joints,  but  more 
particularly  of  those  which  are  very  moveable, 
and  indeed  the  chief  purpose  for  which  it  is 
employed  in  the  economy  of  adult  animals  is 
as  an  important  and  valuable  element  in  these 
moveable  joints.  Articular  cartilage,  there- 
fore, constitutes  a  primary  subdivision  of  this 
texture  by  systematic  writers.  Its  hardness, 
its  elasticity,  and  the  limited  degree  of  or- 
ganization which  it  possesses,  peculiarly  adapt 
it  for  the  purposes  to  which  it  is  applied  in  the 
mechanism  of  the  articulations. 

Although  cartilage  is  chiefly  employed  in 
those  joints  which  possess  considerable  mo- 
bility, it  nevertheless  also  exists  in  joints  which 
are  limited  in  their  motions,  and  as  it  possesses 
peculiar  characters  according  as  it  belongs  to 
one  or  other  of  these  classes  of  articulations, 
we  may  very  conveniently  subdivide  it  into — 
a,  cartilage  of  moveable  articulations,  or  ar- 
ticular cartilage  properly  so  called,  or  diar- 
throdial  cartilage ;  6,  cartilage  of  articula- 
tions very  limited  in  their  motions,  or  cartilage 
of  sutures,  or  synarthrodial  cartilage.  Under 
these  heads  we  propose  to  treat  of  articular 
cartilage. 


248 


ARTICULATION. 


a.  Diarthrodial  cartilage.  —  The  general 
characters  of  this  class  of  articular  cartilage 
may  be  best  examined  on  the  articulating  ex- 
tremities of  the  long  bones.  Here  we  observe 
it  moulded  exactly  to  the  forms  of  those  sur- 
faces, insomuch  that,  after  a  little  maceration, 
the  cartilage  may,  by  careful  dissection,  be 
removed  from  the  bone,  to  which  it  adheres 
with  great  firmness,  and  will  be  found  to  ex- 
hibit an  exact  mould  of  the  articular  ex- 
tremity ;  hence  these  cartilages  have  been  called 
"cartilages  of  incrustation"  This  cartilage 
is  perfectly  distinct  at  the  early  periods  of  life 
from  the  temporary  cartilage  which  forms  the 
nidus  of  the  future  bone,  and  cannot  be  re- 
garded as  a  portion  of  that  cartilage  left  un- 
ossified  ;  this  may  easily  be  seen  by  examining 
a  vertical  section  of  a  femur  or  tibia  at  this 
period  ;  and  the  peculiar  arrangement  of  the 
fibres  of  the  articular  cartilage,  hereafter  to  be 
noticed,  constitutes  an  additional  proof  that  it 
is  completely  distinct  from  that  which  is  after- 
wards transformed  into  bone. 

The  physical  properties  and  general  charac- 
ters of  this  form  of  cartilage  do  not  differ  from 
those  of  the  others ;  it  possesses  the  same 
pearly  whiteness — the  same  apparent  homoge- 
neousness  of  structure — the  same  elasticity — the 
same  absence  of  vessels  carrying  red  blood.  It 
is  not  covered  by  a  perichondrium  ;  the  surface 
towards  the  joint  is  peculiarly  smooth  and  glis- 
tening, and  is  generally  supposed  to  owe  these 
properties  to  its  being  lined  by  a  layer  of  the 
synovial  sac  of  the  joint;  this  point,  however, 
has  been  controverted,  as  we  shall  notice  in  a 
subsequent  part  of  the  article.  The  first  and 
the  most  complete  investigation  of  the  true 
anatomical  construction  of  articular  cartilage 
was  that  announced  by  Dr.  William  Hunter  so 
long  ago  as  1743.*  His  paper  still  deserves 
the  most  attentive  perusal,  not  only  for  the 
actual  information  it  affords  on  its  professed 
subject,  but  as  a  specimen  of  the  careful  and 
original  method  of  observation  pursued  by  its 
distinguished  author.  To  examine  the  structure 
of  articular  cartilages,  it  is  necessary  to  subject 
them  to  boiling  or  along-continued  maceration .f 

"  When  an  articulating  cartilage  is  well  pre- 
pared," says  Dr.  Hunter,  "  it  feels  soft,  yields 
to  the  touch,  but  restores  itself  to  its  former 
equality  of  surface  when  the  pressure  is  taken 
off.  This  surface,  when  viewed  through  a 
glass,  appears  like  a  piece  of  velvet.  If  we 
endeavour  to  peel  the  cartilage  off  in  lamellae, 
we  find  it  impracticable,  but  if  we  use  a  certain 
degree  of  force,  it  separates  from  the  bone  in 
small  parcels,  and  we  never  find  the  edge  of 
the  remaining  part  oblique,  but  always  perpen- 
dicular to  the  subjacent  surface  of  the  bone. 
If  we  view  this  edge  through  a  glass,  it  appears 
like  the  edge  of  velvet,  a  mass  of  short  and 
nearly  parallel  fibres  rising  from  the  bone,  and 
terminating  at  the  external  surface  of  the  carti- 
lage :  and  the  bone  itself  is  planned  out  into 

*  Of  the  Structure  and  Diseases  of  Articular 
Cartilage,  Phil.  Trans,  vol.  xlii. 

t  The  articular  cartilage  on  the  patella  may  be 
selected  as  very  favourable  for  this  purpose.  See 
the  plate  annexed  to  W.  Hunter's  paper. 


small  circular  dimples  where  the  little  bundles 
of  the  cartilaginous  fibres  were  fixed.  Thus 
we  may  compare  the  texture  of  a  cartilage  to 
the  pile  of  velvet,  its  fibres  rising  up  from  the 
bone,  as  the  silky  threads  of  that  rise  from  the 
woven  cloth  or  basis.  In  both  substances  the 
short  threads  sink,  and  bend  in  waves  upon 
being  compressed,  but  by  the  power  of  elasti- 
city recover  their  perpendicular  bearing  as 
soon  as  they  are  no  longer  subjected  to  a 
compressing  force.  If  another  comparison 
was  necessary,  we  might  instance  the  flower 
of  any  corymbiferous  plant,  where  the  fiosculi 
and  stamina  represent  the  little  bundles  of 
cartilaginous  fibres,  and  the  calyx,  upon  which 
they  are  planted,  bears  analogy  to  the  bone."* 

The  total  absence  of  vessels  capable  of  car- 
rying red  blood  in  articular  cartilage  is  proved 
by  the  failure  of  even  the  minutest  injections  to 
pass  into  the  cartilage,  and  a  further  confirma- 
tion of  this  opinion  is  derived  from  the  fact 
that  madder  taken  into  the  system  of  a  young 
animal  does  not  stain  them.  The  attempts  of 
anatomists  to  trace  lymphatics  and  nerves  into 
this  structure  have  been  equally  unavailing. 

The  design  of  articular  cartilages,  as  means 
to  break  the  violence  of  shocks,  is  well  illus- 
trated by  comparing  the  different  arrangement 
of  the  cartilaginous  incrustation  on  convex  arti- 
cular surfaces  from  that  on  concave.  In  the 
former,  we  observe  the  layer  of  cartilage  to  be 
very  thin  at  the  circumference  of  the  articular 
surface,  its  thickest  portion  being  in  the  centre, 
while  the  opposite  arrangement  obtains  on  con- 
cave surfaces  :  there  the  thinnest  portion  of  the 
cartilage  is  in  the  centre,  and  the  layer  increases 
in  thickness  as  it  approaches  the  circumference. 

"  The  articulating  cartilages  are  most  hap- 
pily contrived  to  all  purposes  of  motion  in 
those  parts.  By  their  uniform  surface  they 
move  upon  one  another  with  ease :  by  their 
soft,  smooth,  and  slippery  surface  mutual  abra- 
sion is  prevented  :  by  their  flexibility,  the  con- 
tiguous surfaces  are  constantly  adapted  to  each 
other,  and  the  friction  diffused  equally  over  the 
whole  :  by  their  elasticity,  the  violence  of  any 
shock,  which  may  happen  in  running,  jumping, 
&c.  is  broken  and  gradually  spent;  which 
must  have  been  extremely  pernicious,  if  the 
hard  surfaces  of  bones  had  been  immediately 
contiguous.  As  the  course  of  the  cartilaginous 
fibres  appears  calculated  chiefly  for  this  last 
advantage,  to  illustrate  it,  we  need  only  reflect 
on  the  soft  undulatory  motion  of  coaches,  which 
mechanics  want  to  procure  by  springs,  or  upon 
the  difference  betwixt  riding  a  chamber-horse 
and  a  real  one.vf 

*  Loc.  cit.  p.  516. 

t  Hunter,  in  loco  citato.  Hunter's  account  of 
articular  cartilage  is  completely  confirmed  by  M. 
De  Lasone  in  a  paper  in  the  Mem,  de  1'Academie 
Royale  des  Sciences,  An  1752.  He  describes  the 
cartilage  as  "  une  multitude  des  petits  filets  adosses 
et  lies  les  uns  aux  autres  tous  perpendiculaires  an 
plan  de  1'os,  en  un  mot  parfaitement  semblables 
par  leur  structure,  ou  par  leur  position  a  la  substance 
emaillee  des  dents,  laquelle  n'est  composee,  comme 
on  sait,  que  de  filets  osseux,  poses  perpendiculaire- 
ment  sur  le  corps  de  la  dent :  la  comparaison  est 
des  plus  exactes." 


. 


ARTICULATION. 


249 


b.  Synarthrodial  cartilage. — The  cartilages 
synarthrodial  articulations  are  destined  in 
some  degree  to  act  as  bonds  of  union,  as  well 
as  means  of  separation  and  for  the  prevention 
of  the  effects  of  concussion.  They  are  simply 
cartilaginous  laminae  interposed  between  the 
osseous  articular  surfaces,  very  adherent  to  both, 
and  adherent  likewise  by  their  margins  to  the 
periosteum  or  ligamentous  expansions  which 
may  pass  from  one  bone  to  another.  We  find 
instances  of  these  cartilages  in  the  sacro-iliac 
symphysis,  or  synchondrosis,  as  it  has  been 
called  from  the  junction  of  the  bones  by  carti- 
lages;* also  in  the  sutures,  where  there  are 
very  thin  cartilaginous  laminae  interposed  be- 
tween the  osseous  margins.  These  laminae 
will  be  found  to  be  triangular  in  their  section, 
the  thin  edge  or  apex  being  internal,  which,  as 
Meckel  observes,  may  in  some  degree  account 
for  the  earlier  obliteration  of  the  sutures  on  the 
internal  than  on  the  external  surface  of  the 
cranium.  These  cartilages  of  sutures  are  not 
strictly  permanent ;  they  disappear  with  age : 
and  according  to  Beclard,  hold  the  midway,  as 
to  frequency  of  ossification,  between  permanent 
and  temporary  cartilages.f 

The  cartilages  of  the  ribs  perform  in  some 
degree  the  office  of  articular  cartilage ;  they  are 
situated  between  two  osseous  surfaces ;  they 
form  bonds  of  union,  and  their  elasticity  is 
eminently  essential  to  the  full  performance  of 
the  movements  of  the  thorax. 

In  fishes  most  of  the  moveable  articulations 
are  provided  with  elastic  cartilages,  which  serve 
the  double  purpose  of  forming  bonds  of  union 
as  well  as  of  permitting  motion  by  their  elasticity. 

3.  Fibro-cartilage. — This  remarkable  struc- 
ture, called  by  the  older  anatomists  ligamentous 
cartilage  or  cartilaginiform  ligament,  is  made 
much  use  of  in  the  articulations ;  and  it  is  well 
adapted  for  a  means  of  union,  by  reason  of  its 
great  strength,  which  it  owes  to  its  ligamentous 
part,  and  of  its  elasticity,  for  which  it  is  indebted 
to  its  cartilaginous  portion.  We  find  fibro- 
cartilage  to  be  connected  with  the  joints  under 
three  forms  : 

a.  In  the  form  of  laminae,  free  on  both  sur- 
faces to  a  greater  or  less  extent,  and  lined  to 
the  same  extent  by  the  synovial  membrane  re- 
flected upon  them. |  These  are  the  interarti- 

*  No  one  can  have  failed  to  notice  the  peculiar 
yellow  appearance  of  the  cartilage  in  the  sacro- 
iliac  articulation.  Does  that  arise  from  an  admix- 
ture of  the  yellow  elastic  tissue  with  the  pure  carti- 
lage, by  which  the  elasticity  of  the  latter  is  in- 
creased ? 

t  It  is  doubted  by  some  whether  these  cartilagi- 
nous laminje  can  be  admitted  into  the  class  of  arti- 
cular cartilages;  they  being  regarded  as  forming  a 
nidus  for  the  extension  of  the  flat  cranial  bones, 
and  the  sutures  being  supposed  to  be  useful  only  for 
this  purpose,  viz.  to  admit  of  the  growth  of  these 
bones  at  their  margins  in  a  manner  analogous  to 
that  of  long  bones  at  their  extremities.  See  Soem- 
merring  de  Corp.  Hum.  Fab.  t.  i.  p.  212,  and  Gibson 
on  the  use  of  sutures  in  the  skulls  of  animals, 
Manchester  Memoirs,  2d  series,  vol.  i. 

t  This  point,  however,  is  liable  to  the  same 
objections  as  that  of  the  continuity  of  the  synovial 
membrane  over  diaithrodial  articular  cartilages, 
which  will  be  considered  in  a  subsequent  part  of  the 
article. 


cular  cartilages  or  menisci  of  authors.  They 
are  found  in  the  temporo-maxillary,  sterno- 
clavicular,  and  tibio-femoral  articulations,  some- 
times in  the  acromio-clavicular,  between  the 
bodies  of  the  cervical  vertebrae  in  birds,  and  in 
general  in  those  joints  where  there  is  constant 
and  extensive  motion,  and  consequently  where 
the  articular  surfaces  are  exposed  to  consider- 
able friction.  The  principal  use  of  these  fibro- 
cartilaginous  laminae  must  unquestionably  be 
to  guaid  against  any  bad  consequences  likely 
to  arise  from  this  continued  friction ;  this  is 
particularly  obvious  in  the  sterno-clavicular 
articulation.  To  increase  the  depth  of  an  arti- 
cular excavation  is  another  object,  as  appears 
from  the  semilunar  cartilages  of  the  knee-joint; 
and  moreover,  in  conjunction  with  the  attain- 
ment of  these  two  objects,  to  ensure  in  all  the 
motions  of  the  joint  a  perfect  adaptation  of  the 
articular  surfaces  to  one  another,  as  will  appear 
obvious  to  any  one  who  carefully  considers  the 
construction  of  the  temporo-maxillary  or  even 
of  the  knee-joint. 

It  will  be  observed,  that  I  do  not  include  in 
the  class  of  interarticular  fibro-cartilages,  the 
lamina  which  is  commonly  known  by  the  name 
of  the  triangular  cartilage  of  the  wrist  joint,  as  is 
done  by  all  the  systematic  writers  I  have  looked 
into ;  for,  first,  it  does  not  appear  to  me  to  be 
fibro-cartilaginous  in  its  structure ;  it  is  purely 
cartilaginous ;  and,  secondly,  it  is  not  interar- 
ticular, in  the  sense  in  which  we  here  use  that 
term,  viz.,  as  lying  between  two  articular  surfaces. 
This  lamina  seems  to  be  merely  an  extension  of 
the  cartilaginous  incrustation  of  the  inferior  ex- 
tremity of  the  radius,  which  completes  the  ar- 
ticular surface  for  the  reception  of  the  first  row 
of  carpal  bones.  The  scaphoides  and  lunare  are 
provided  for  by  the  radius;  but  as  the  ulna 
could  not  be  brought  into  the  composition  of 
the  wrist-joint  without  interfering  with  the 
motions  of  the  inferior  radio-ulnar  articulation,  a 
structure  such  as  the  triangular  cartilage,  was 
necessary — one  which  would  present  a  sufficient 
opposing  surface  to  the  articular  portion  of  the 
os  cuneiforme,  and  which  would  not  impede  or 
obstruct  the  necessary  motions  of  the  joint 
between  the  radius  and  ulna. 

In  the  cases  of  the  temporo-maxillary  and 
sterno-clavicular  articulations,  these  fibro-carti- 
lages form,  in  general,  complete  septa  between 
two  portions  of  the  joint :  so  that  there  are  then 
two  synovial  sacs;  but  sometimes  there  is  a  per- 
foration in  the  centre  of  the  fibro-cartilage. 

b.  The  second  class  of  articular  fibro-carti- 
lages consists  of  those  which  Meckel  designates 
fibro-cartilages  of  circumference,  or  cylindrical 
fibro-cartilages.  They  form  fibro-cartilaginous 
brims  to  certain  articular  excavations;  they  are 
triangular  in  their  section,  attached  by  their 
basis  to  the  osseous  margin  of  the  articular 
cavity,  and  free  at  their  apices,  lined  by  synovial 
membrane  on  the  whole  of  one  side,  and  a 
great  part  of  the  other.  They  are  to  be  found 
only  in  two  joints,  namely,  on  the  margin  of 
the  acetabulum  in  the  hip-joint,  and  on  the 
edge  of  the  glenoid  cavity  in  the  articulation  of 
the  shoulder ;  in  the  former,  this  fibro-cartilage 
is  much  larger  and  stronger,  and  is  evidently 


250 


ARTICULATION. 


intended  to  obviate  the  ill  consequences  which 
must  have  resulted  from  the  violent  application 
of  the  neck  of  the  femur  against  the  bony 
margin  of  the  acetabulum :  for,  where  the 
margin  of  that  cavity  is  ligamentous,  viz.,  at 
the  notch  on  its  inner  side,  this  fibro-cartilage 
does  not  exist. 

c.  The  most  remarkable  and  beautiful  variety 
of  this  structure  belongs  to  the  third  class.  It 
consists  of  fibro-cartilaginous  laminae,  generally 
of  considerable  thickness,  which  intervene  be- 
tween two  bones  and  adhere  intimately  to  each. 
Examples  of  it  are  to  be  found  between  the 
bodies  of  the  vertebrae,  (inter vertebral  sub- 
stance)— between  the  pieces  of  the  sacrum  in 
early  life — between  the  sacrum  and  coccyx, 
and  between  the  pieces  of  the  latter — also,  be- 
tween the  ossa  pubis  at  the  joint  called  the 
symphysis  pubis.  In  this  class  of  fibro-car- 
tilages  too,  we  may  place  that  which  is  situ- 
ated between  the  scaphoid  and  lunar  bones  in 
the  carpus. 

It  is  evident  that  these  fibro-cartilages  are 
useful,  not  only  as  very  powerful  bonds  of 
union,  but  also  as  elastic  cushions  placed  be- 
tween the  bones  to  prevent  the  concussion 
which  must  necessarily  result,  did  the  unyield- 
ing bony  surfaces  come  together  with  any  de- 
gree of  force.  No  where  is  this  so  beautifully 
exhibited  as  in  that  chain  of  bones  which 
forms  the  spinal  column  in  the  mammiferous 
vertebrata,  the  strength  and  flexibility  of 
which  result  from  the  fibro-cartilaginous  discs, 
which,  placed  between  the  bodies  of  the  ver- 
tebrae, are  commonly  called  intervertebral  car- 
tilages. 

As  to  the  structure  of  articular  fibro-cartilage, 
we  can  distinctly  observe,  without  any  process 
of  dissection,  that  it  is  compounded  of  fibrous 
tissue  as  well  as  of  cartilage.  As  these  nbro- 
cartilages  generally  assume  more  or  less  of  the 
circular  form,  we  find  that  the  fibrous  tissue  is 
most  abundant  towards  the  circumference,  and 
that  the  cartilage  is  most  manifest  at  the  centre. 
In  the  intervertebral  substance,  the  fibrous 
tissue  is  arranged  in  concentric  laminae,  placed 
vertically  behind  one  another.  Each  lamina  is 
composed  of  a  series  of  interlacing  fibres,  which 
have  intervals  between  them ;  these  intervals, 
as  well  as  those  between  the  laminae,  are  filled 
by  cartilaginous  tissue ;  towards  the  centre  the 
fibrous  laminae  diminish  in  number,  the  inter- 
vals become  large,  and  at  length  the  fibrous 
tissue  disappears  in  toto ;  hence  the  gradually 
diminishing  density  towards  the  centre,  which 
characterises  the  intervertebral  substance.  In 
fishes,  there  is  such  a  diminution  of  density, 
that  the  central  part  is  fluid,  but  here  the  sur- 
faces of  the  vertebras  are  excavated,  not  plane 
as  in  the  mammiferous  vertebrata,  and  the  cha- 
racter of  the  articulation  is  thereby  materially 
altered.  The  incompressible  central  fluid  forms 
a  ball,  round  which  the  cup-like  excavations  of 
the  vertebras  play,  while  the  fibro-cartilage  at 
the  circumference  is  made  available  in  the  la- 
teral motions  of  the  spine. 

Of  the  three  varieties  of  fibro-cartilage  above 
enumerated,  the  menisci  possess  the  most  car- 
tilage in  their  structure,  and  the  circumferential 


fibro-cartilages  the  greatest  quantity  of  fibrous 
tissue. 

It  may  be  questioned  whether  that  peculiar 
structure  which  intervenes  between  the  base  of 
the  skull  and  the  condyle  of  the  lower  jaw  in 
the  whalebone  whale,  (baltena  mysticetus)  be- 
longs to  the  class  of  fibro-cartilages,  although 
it  seems  to  bear  a  nearer  resemblance  to  that 
than  to  any  of  the  other  structures  employed  in 
the  composition  of  joints.  The  following  is 
Sir  Everard  Home's  description  of  it.*  "  Be- 
tween the  condyles  of  the  lower  jaw  and  the 
basis  of  the  skull  is  interposed  a  thick  sub- 
stance, made  up  of  a  network  of  ligamentous 
fibres,  the  interstices  of  which  are  filled  with 
oil,  so  that  the  parts  move  readily  on  each  other. 
The  condyles  have  neither  a  smooth  surface 
nor  a  cartilaginous  covering,  but  are  firmly 
attached  to  the  intermediate  substance,  which 
in  this  animal  is  a  substitute  for  the  double 
joint  met  with  in  the  quadruped,  and  is  cer- 
tainly a  substitute  of  the  most  simple  kind." 

4.  Ligament. — The  term  ligament,  as  it  is 
used  by  systematic  writers  on  descriptive  ana- 
tomy, is  by  no  means  confined  to  portions  of 
the  "  fibrous  system"  of  Bichat,  although  all 
the  articular  ligaments  (properly  so  called)  be- 
long to  that  system.  Weitbrecht  comprehends 
under  this  term  all  fibrous  structures  in  and 
about  joints,  including  the  fibrous  sheaths  of 
tendons,  and  also  all  membranous  folds,  which 
are  in  any  way  concerned  in  maintaining  soft 
parts  or  viscera  in  proprio  situ.  I  apprehend, 
however,  that  a  better  definition  of  articular 
ligament  could  not  be  given  than  the  following, 
which  is  that  of  Weitbrecht,  the  words  printed 
in  italics  being  added,—"  Ligamentum  est  par- 
ticula  corporis,  plerumque  albicans,  interdum 
jlava,  ex  fibris  flexilibus,  interdum  elasticis, 
plerumque  parallele  concretis,  in  substantiam 
tenacem  fibrosam,  ruptioni  fortiter  resistentem, 
et  solidam  compacta,  eum  in  finem  creata  ut 
duae  pluresve  partes  quaa  alias  divulsae  per  se 
subsisterent,  adunentur  atque  in  situ  respectivo 
determinentur."f  Most  of  the  articular  liga- 
ments are  employed  to  unite  the  bones  which 
compose  a  joint ;  they  also  will  be  found  uniting 
some  of  the  interarticular  cartilages  within 
joints,  or  passing  from  one  part  of  a  bone  to 
another  (forming  the  "  mixed"  class  of  liga- 
ments of  Beclard) ;  and  such  is  the  vagueness 
with  which  names  are  applied  in  descriptive 
anatomy,  that  folds  of  the  sy  no  vial  membrane 
often  receive  this  appellation  without  the  least 
title  to  it. 

Articular  ligaments  are  divisible  as  regards 
their  forms  into  two  species,  the  capsular  and 
the  funicular  or  fascicular.J 

Capsular  ligaments  are  generally  cylindrical 
in  shape,  or  rather  barrel-shaped,  being  wider 
in  the  centre  than  at  the  extremes.  Each  ex- 
tremity envelopes  one  of  the  bones  that  enters 
into  the  formation  of  the  joint,  so  that  the  arti- 
cular cavity  is  completely  surrounded  by  and 
enclosed  within  the  ligamentous  capsule.  Liga- 

*  Comp.  Anat.  vol.  i.  p.  83. 
t  Syndesmologia,  §  5. 

.        T>__1_    -J  A  __  ..  A.       /~1 


oynaesmoiogio.,  y  t». 
Beclard,  Anat.  Gen. 


ARTICULATION. 


251 


merits  of  this  kind  are  composed  of  fibres 
which  are  closely  interwoven  with  each  other, 
and  they  sometimes  receive  accessions  from 
bundles  of  ligamentous  fibres  coming  from 
neighbouring  bony  prominences  (these  fibres 
being  generally  called  acceswri/  ligaments.) 
Capsular  ligaments  are  not  calculated  to  re- 
strict the  extent  or  direction  of  motion  be- 
tween the  bones  which  they  surround,  and 
we  consequently  find  them  only  in  that 
kind  of  joint  which  admits  of  motion  in  all 
directions,  viz.  the  enart/iroais  or  ball-and- 
socket  joint,  of  which  the  only  examples  in 
the  human  subject  are  to  be  met  with  in  the 
hip  and  shoulder.  The  internal  or  articular 
surface  of  capsular  ligaments  is  to  a.  great 
extent  lined  by  one  lamina  of  the  synovial 
membrane,  which  is  reflected  upon  it  from  the 
articular  portion  of  the  most  moveable  of  the 
bones  which  form  the  joint. 

Funicular  ligaments  are  found  in  the  form  of 
rounded  cords  or  flattened  bands  :  they  exist 
generally  on  the  exterior  of  joints,  very  rarely 
on  the  interior,  and  always  externally  to  the  sac 
of  the  synovial  membrane.  They  pass  from 
bone  to  bone,  adherent  sometimes  to  the  syno- 
vial membrane  of  the  articulation,  sometimes  to 
the  intervening  fibro-cartilage.  In  ginglymoid 
joints  they  are  always  placed  on  the  sides,  and 
are  called  lateral  liyaments ;  sometimes  they 
cross  or  decussate  with  each  other,  whence  the 
appellation  crucial,  and  sometimes  a  ligament 
of  this  class  assumes  a  nearly  circular  course, 
and  forms  a  greater  or  smaller  portion  of  the 
circumference  of  a  circle,  the  remainder  of  the 
round  being  completed  by  the  bone  into  which 
the  extremities  of  the  ligament  are  fixed ;  a 
ring  is  in  this  way  produced  within  which  the 
head,  or  a  special  process  of  another  bone,  is 
enclosed,  as  is  seen  to  be  the  case  particularly 
with  the  head  of  the  radius  in  the  superior 
radio-ulnar  articulation,  and  with  the  processus 
dentatus  in  the  j<>int  between  the  axis  and 
atlas :  the  ligament  in  such  instances  is  called 
coronary.  When  a  ligament  is  concealed  in 
the  interior  of  a  joint,  although  situated  exter- 
nally to  the  synovial  sac,  or,  to  speak  more 
correctly,  in  the  space  between  the  articular 
surfaces,  it  is  called  an  internal  ligament,  e.  g. 
the  ligamentum  teres  of  the  hip-joint,  the  mu- 
cous ligament  of  the  knee,  or  the  transverse 
ligament  of  the  same  articulation. 

Elastic  ligament. — Hitherto  we  have  been 
examining  ligamentous  structure,  one  of  whose 
most  prominent  characteristics  is  the  want  of 
elasticity  ;  but  we  now  come  to  a  kind  of  liga- 
ment which  forms  a  most  valuable  constituent 
in  the  mechanism  of  some  joints,  and  is  emi- 
nently distinguished  for  the  great  elasticity  which 
it  possesses.  It  differs  from  ordinary  ligament 
by  its  yellow  colour,  (whence  the  French  ap- 
pellation tissu  jaunCj)  as  well  as  by  its  elasti- 
city. We  find  it  in  the  human  subject  most 
developed  in  the  ligamenta  subflava  of  the 
vertebrae.  In  joints,  as  elsewhere,  this  tissue 
is  employed  to  restore  to  the  position  of  quie- 
scence, parts  which  have  been  previously  acted 
upon  by  muscular  contraction.  John  Hunter 


fully  appreciated  the  value  and  utility  of  this 
structure  in  supplying  the  place  of  muscle,  with 
less  expense  of  exertion  to  the  economy,  and 
assigned  it  a  place  in  the  arrangement  of  his 
museum.*  The  thyro-hyoid  and  crico-thyroid 
ligaments  in  man  are  formed  of  this  struc- 
ture. 

5.  Synovial  membrane. — The  articular  syno- 
vial membranes,  (by  the  older  anatomists  called, 
and  confounded  with,  the  capsular  ligaments,) 
like  all  others,  possess  in  common  with  serous 
membranes  the  form  of  a  sac  shut  in  all  points; 
they  line  the  whole  interior  of  the  joints,  and 
secrete  from  their  internal  surface  a  peculiar 
fluid,  obviously  destined  for  the  lubrication  of 
the  articular  surfaces.  These  membranes  are 
remarkable  for  their  great  tenuity;  they  are 
transparent;  in  a  state  of  inflammation,  their 
vascularity,  which  is  imperceptible  during 
health,  becomes  very  apparent  by  the  general 
redness  which  the  membrane  assumes ;  arid 
their  internal  or  secreting  surface  is  easily  dis- 
tinguished from  the  external,  by  contrasting  the 
smooth  and  glistening  appearance  of  the  former 
with  the  roughness  which  the  latter  receives 
from  the  cellular  tissue  and  ligamentous  fibres 
which  adhere  to  it.  The  internal  surface  of 
the  membrane  is  sometimes  thrown  into  folds 
with  fringe-like  margins,  which  project  into 
its  cavity  or  sac.  These  folds  contain  more 
or  less  of  cellular  tissue  and  a  number  of 
pellets  of  fat,  which  being  supplied  with  ves- 
sels, the  margin  of  the  synovial  fringe  is  some- 
times tinged  red.  These  folds  are  compared, 
and  certainly  with  much  justice,  to  the  epi- 
ploic  folds  of  the  abdominal  serous  mem- 
branes, more  especially  to  the  appendices 
epiploicre  of  the  great  intestine.  Beclard  sup- 
poses that  these  fringes  are  specially  the  seat  of 
the  synovial  secretion,  which  being  perspiratory 
likewise  takes  place,  though  less  abundantly 
and  manifestly,  from  the  rest  of  the  synovial 
surface.  The  best  examples  of  these  folds 
occur  in  the  knee  and  hip-joints,  in  the  former 
of  which  they  have  been  absurdly  called  alar 
ligaments. 

Some  idea  may  be  formed  of  the  manner  in 
which  the  synovial  membrane  is  related  to  the 
other  articular  structures  by  examining  the  an- 
nexed figure,  (jig.  Ill,)  representing  a  vertical 
section  of  the  knee-joint.  The  cut  margin  of 
the  synovial  membrane  is  indicated  by  «,  which 
after  lining  the  posterior  surface  of  the  patella 
and  ligamentum  patellae,  is  reflected  upon  the 
condyles  of  the  femur,  whence  it  is  carried  in 
front  of  the  crucial  ligaments  to  line  the  arti- 
cular surface  of  the  head  of  the  tibia,  and  from 
that  is  again  reflected  upwards,  and  is  con- 
tinuous with  the  portion  lining  the  posterior  car- 
tilaginous surface  of  the  patella.  This  descrip- 
tion is  founded  on  the  opinion,  which  I  believe 
to  be  correct,  that  the  analogy  between  serous 
and  synovial  membranes  is  accurate,  in  so  far 
as  their  possessing  in  common  the  form  of 
shut  sacs  is  concerned.  On  this  subject,  how- 


*  Vide  Home's  Lect.  on  Comp.  Aaat.  Lcct.  i. 
vol.  i. 


252 


ARTICULATION. 


Fig.  111. 


ever,  anatomists  are  by  no  means  likely  ever 
to  be  unanimous,  because  of  the  difficulty  or 
impossibility  of  tracing  by  the  ordinary  me- 
thods of  dissection  the  synovial  membrane 
over  the  articular  cartilages.  The  continuity  of 
this  membrane  over  the  cartilage  was  first 
distinctly  announced  and  described  by  Dr. 
W.  Hunter,  in  the  paper  to  which  we  have 
already  referred  in  the  Philosophical  Trans- 
actions :  after  him  Soemm erring  described  it, 
and  still  later  Bichat,  who  insisted  more  par- 
ticularly on  its  analogy  with  serous  mem- 
branes. Bichat's  description  has  been  followed 
by  Meckel,  Beclard,  and  most  of  the  anato- 
mists of  modern  times;  but  its  accuracy  has 
been  called  in  question  by  Cruveilhier,* 
Gordon,f  Magendie,J  Blandin,§  and  more  re- 
cently by  Gendrin||  and  Velpeau.^F 

The  advocates  for  the  continuity  of  the  syno- 
vial membranes  over  the  diarthrodial  cartilages, 
found  their  opinion  on  the  following  facts  : — 
1 .  Synovial  membranes  elsewhere,  lining  ten- 
dinous sheaths  or  bursae  mucosae,  are  distinctly 
and  obviously  shut  sacs.  2.  We  do  not  find 

*  Observations  sur  les  Cartilages  diarthrodiaux. 
Arch.  Gen.  de  Med.  torn.  iv.  p.  161. 

t  Gordon  says,  "  the  continuation  of  the  syno- 
vial membranes  over  the  surface  of  articulating 
cartilages  is,  I  am  convinced  from  a  number  of  ex- 
periments, altogether  an  anatomical  refinement." — 
System  of  Human  Anatomy,  p.  261 . 

$  Compend.  of  Physiology,  by  Milligan,  p.  450. 

§  Additions  a  Bichat,  par  Beclard  et  Blaiidin, 
p.  345. 

(I  Hist.  Anat.  des  Inflam.  t.  i.  p.  60. 

II   Anat.  Chir.  ed.  2de,  t.  i.  p.  176. 


cartilage  to  present  the  smooth  and  polished 
aspect  exhibited  by  the  articular  surfaces,  ex- 
cepting where  it  is  connected  with  synovial 
membrane,  as  it  evidently  is  to  at  least  a  cer- 
tain extent  in  the  moveable  articulations.  3.  If 
by  an  oblique  cut  we  raise  a  slice  from  an  arti- 
cular cartilage,  and  turn  it  back  so  as  to  rupture 
it  at  its  base,  we  shall  find  it  still  retained  in 
connexion  with  the  rest  of  the  cartilage  by  a 
thin  pellicle,  which  seems  to  have  all  the  cha- 
racters of  synovial  membrane.  A  similar  mem- 
brane may  be  seen  by  sawing  a  bone  vertically 
down  to  the  cartilage,  and  then  breaking  the 
cartilage  by  forcibly  separating  the  segments. 

4.  Some  observers  state  that  they  have  seen  the 
redness  of  inflammation  affecting  the  synovial 
membranes  prolonged  over  the  cartilage,*  but 
becoming  gradually  less  marked  towards  the 
centre — (this,  I  must  confess,  I  have  never  seen). 

5.  Bands  of  adhesion  are  also  said  to  have  been 
met  with  in  some  cases  of  chronic  inflammation 
of  the  synovial  membrane,  passing  from  the  ar- 
ticular surfaces,  as  well  as  from  other  parts  of 
the  interior  of  the  joint.     6.  In  that  peculiar 
disease  of  the  synovial  membrane  described  by 
Brodie,the  pulpy  substance  has  been  seen  on  the 
articular  cartilages,  as  well  as  on  the  menisci.f 

On  the  other  hand,  the  opponents  of  this 
opinion  deny  :  1,  that  the  membrane  demon- 
strable by  slicing  the  cartilage  in  the  way  above 
described,  is  any  thing  else  than  a  very  thin 
lamina  of  cartilage ;  2,  they  say  that  by  even 
the  most  successful  injection  the  fluid  cannot 
be  made  to  pass  beyond  the  margin  of  the  car- 
tilage ;  3,  they  assert  that  inflammation  always 
stops  abruptly  at  the  circumference  of  the  car- 
tilage ;  4,  and  that  if  a  synovial  membrane  did 
exist  on  the  free  surface  of  the  cartilage,  there 
would  take  place  a  continual  exhalation  of  sy- 
novia from  the  articular  surface,  contrary  to  what 
was~found  to  be  the  case  in  an  experiment  tried 
by  Cruveilhier :  synovia  was  freely  exhaled  from 
the  membrane  lining  the  ligaments,  and  after 
having  been  wiped  off  reappeared  with  rapidity ; 
but  not  so  over  the  articular  cartilage,  the  sur- 
face of  which  became  quite  dry.  J 

Cruveilhier,  however,  relates  a  case  which  in 
some  degree  invalidates  his  own  conclusions  ; 
it  was  one  in  which  fungous  granulations  sprang 
from  the  articular  surfaces  of  the  femur  and 
tibia  in  the  knee-joint,  and  by  their  adhesion 
produced  anchylosis  of  the  joint :  this  fact  Cru- 
veilhier §  very  candidly  expresses  his  inability 

*  I  am  uncertain  whether  the  fourth  case  related 
by  Sir  B.  Brodie  in  the  last  edition  of  his  work  on 
the  joints,  may  not  be  regarded  as  affording  an  in- 
stance of  this.  In  the  account  of  the  post-mortem 
examination  it  is  said,  "  The  synovial  membrane 
was  everywhere  of  a  red  colour,  as  if  stained  by 
the  secretion,"  p.  15.  Beclard,  whose  powers 
and  accuracy  of  observation  few  will  be  disposed 
to  question,  speaks  with  the  confidence  of  one  who 
had  seen  this  extension  of  the  vessels  over  the  car- 
tilage.— Anat.  Gen.  p.  214. 

t  Vide  the  17th,  18th,  19th,  21st,  and  22d  cases 
recorded  in  Sir  B.  Brodie's  work. 

|  Cruveilhier,  loc  cit. 

§  He  confesses,  "  ma  conviction  n'est  pas  cepen- 
dant  pleine  et  enliere." 


ARTICULATION. 


253 


to  explain  without  admitting  either  the  exist- 
ence of  the  synovial  membrane,  or  the  organi- 
zation* of  the  cartilages.  Velpeau,t  too,  al- 
though he  asserts  that  the  synovial  membrane 
"  terminates  at  the  circumference  of  the  carti- 
lages," furnishes  us  with  an  argument  in  oppo- 
sition to  his  own  views :  namely,  that  no  appre- 
ciable line  of  demarcation  can  be  detected 
indicating  where  the  synovial  membrane 
ceases.  "  Viewed  in  this  way,"  he  says,  "  the 
synovial  apparatus  consists  of  surfaces,  mem- 
branes, and  glandular  folds,  between  which 
there  exists  not  the  least  interruption,  and 
the  use  of  which  is  to  isolate  the  interior  of 
the  joint  from  the  tissues  which  surround  it." 

It  will  appear  then  sufficiently  evident  that 
the  weight  of  argument  preponderates  in  favour 
of  the  doctrine  that  the  synovial  membranes 
line  the  articular  surface  of  the  cartilages,  and 
that  maintains  their  analogy  with  the  serous 
membranes,  an  analogy  which  receives  the 
strongest  support  from  the  physical  properties 
of  the  synovial  membrane,  from  its  obvious 
functions  during  health,  and  from  the  diseases 
with  which  it  is  affected ;  and  I  apprehend, 
that  nothing  tends  more  fully  to  establish  iden- 
tity or  similarity  in  the  nature  of  two  mem- 
branes, than  the  fact  of  a  close  resemblance 
between  their  morbid  conditions.  We  may 
add,  what  was  long  ago  remarked  by  W. 
Hunter,  that  this  question  as  to  the  continuity 
of  the  synovial  membrane  on  the  cartilages  is 
very  similar  to  that  as  to  the  continuity  of 
the  conjunctiva  over  the  cornea  of  the  eye; 
the  affirmation  of  which  latter  question,  Gordon 
considers  equally  an  anatomical  refinement  as 
that  of  the  former. 

VelpeauJ  ascribes  much  importance  to  the 
dense  and  fine  cellular  tissue  which  is  sub- 
jacent to  the  synovial  membrane  and  is  ana- 
logous to  the  subserous  cellular  tissue  else- 
where. This  would  appear  to  be  the  seat  of 
the  vessels  which  in  a  state  of  inflammation 
give  rise  to  the  red  colour  of  the  synovial  mem- 
brane. He  particularly  alludes  to  it  as  afford- 
ing a  clue  by  which  the  formation  of  loose 
cartilaginous  bodies  in  joints  can  be  explained ; 
these  he  supposes  to  originate  in  sanguineous 
effusions  into  this  tissue,  which  subsequently 
become  indurated  and  cartilaginous,  and  push 
the  synovial  membrane  before  them  into  the 
cavity  of  the  joint.  It  will  be  remembered  by 
many  readers  that  this  opinion  is  very  similar 
to  that  of  John  Hunter  regarding  the  origin  of 
these  bodies.  § 

Allusion  has  already  been  made  to  the  fatty 
bodies  which  are  found  in  connexion  with 

*  This  is  a  bad  word  ;  we  cannot'  deny  the  orga- 
nization of  cartilages,  however  we  may  deny  that 
they  are  supplied  with  red  blood.  It  has  been  said, 
I  know  not  with  what  authenticity,  that  cartilages 
have  become  yellow  in  jaundice. 

f  Loc.  cit.  pp.  172  and  174.  He  expresses  his 
opinion  much  more  decidedly  in  the  art.  ARTICU- 
LATIONS, MALADIES  DES.  Diet,  de  Med. 

t  Loc.  cit.  v.  i.  p.  173. 

§  See  Home's  Paper,  in  Trans,  of  a  Soc.  for  the 
improvement  of  Med.  and  Chirurg.  Knowledge, 


most  of  the  joints,  and  in  general  lying  behind 
the  synovial  fringes  formerly  described.  These 
fatty  pellets  were  supposed  by  Clopton  Havers* 
to  be  the  agents  of  the  synovial  secretion,  and, 
in  consequence,  have  obtained  much  celebrity 
under  the  title  of  Haversian  glands.^  The 
opinion  of  Havers  and  his  followers  as  to  their 
glandular  nature  was  successfully  combated  by 
Bichat,  who  proved  that  they  were  merely 
composed  of  adipose  substance,  and  in  no 
way  concerned  in  the  function  of  synovial 
secretion  :  for  1st,  the  secretion  of  synovia  takes 
place  where  no  such  bodies  exist,  as  in  almost 
all  the  bursae  mucosae,  and  tendinous  sheaths  ; 
and  2d,  these  bodies  have  no  trace  of  glan- 
dular structure,  nor  are  they  provided  with  any 
thing  resembling  an  excretory  duct ;  whilst,  on 
the  other  hand,  they  possess  all  the  properties 
of  fat. 

The  synovial  sac  is  lubricated  by  the  sy- 
novia, also  called  unguen  articulare,  axungia 
articularis.  How  is  this  secreted  ?  We  believe 
it  to  be  a  perspiratory  secretion  precisely  similar 
to  that  of  the  serum  from  serous  membranes. 
Its  formation  cannot  be  imputed  to  a  com- 
bination of  the  serosity  of  the  blood  with  the 
fat,  nor  to  the  transudation  of  the  marrow  through 
the  extremities  of  the  bones,  nor,  with  Desault, 
to  a  sweating  from  all  the  parts  which  enter 
into  the  composition  of  the  articulation,  inas- 
much as  the  chemical  analysis  of  synovia 
proves  that  it  is  essentially  different  from  any 
oily  fluid,  and  does  not  contain  a  trace  either 
of  elaine  and  stearine. 

In  addition  to  the  structures  already  named 
as  entering  intrinsically  into  the  formation  of 
joints,  we  find  that  the  tendons  and  muscles, 
which  lie  in  the  immediate  vicinity  of  or  which 
surround  the  joints,  contribute  much  to  their 
strength  and  security.  In  joints  of  the  hinge 
kind  we  generally  see  the  anterior  and  poste- 
rior parts  protected  more  or  less  by  the  tendons 
of  muscles,  and  even  by  muscles  themselves 
passing  from  one  segment  of  a  limb  to  an- 
other, and  here  it  frequently  happens  that  the 
tendon  is  bound  down  on  the  bones  which  form 
the  member,  by  a  fibrous  expansion  of  great 
strength,  lined  by  a  synovial  membrane  of  the 
same  characters  as  the  articular,  but  adapted  in 
its  form  to  the  osseo-fibrous  canal  in  which  the 
tendon  is  placed,  e.g.  the  tendons  of  the  fingers. 
The  protection  and  strength  afforded  by  mus- 
cles is  particularly  evinced  in  the  case  of 
the  shoulder-joint,  where  the  capsular  ligament 
is  closely  embraced  by  four  muscles,  whose 
tendons  become  identified  with  the  fibrous 
capsule  as  they  go  to  be  inserted  into  the  bone. 
A  muscular  capsule,  as  it  were,  is  thus  provided 
for  this  joint,  by  which  the  bones  are  main- 
tained much  more  firmly  and  powerfully  in 
apposition  than  were  they  kept  together  by 
an  uncontractile  ligamentous  capsule  alone ; 
hence  the  elongation  of  the  arm  which  ap- 

*  Osteologia  Nova  :  Lond.  1691. 

t  Weitbrecht  called  these  fatty  bodies,  "  Adi- 
poso-glandulosa? ; "  and  Cowper,  "mucilaginous 
glands."  See  them  figured  in  Monro's  work  on  the 
Bursae,  Tab.  viii. 


254 


ARTICULATION. 


pears  as  a  consequence  of  paralysis,  and  hence 
also  the  greater  liability  to  luxation  which 
exists  in  a  debilitated  state  of  the  system. 
Articular  or  capsular  muscles  thus  placed,  have 
also  the  effect,  as  it  is  said,  of  preventing 
the  pinching  of  the  capsule  or  synovial  mem- 
brane between  the  articular  extremities  of  the 
bones  in  the  different  motions  of  the  joint. 

The  joints  are  very  generally  copiously  sup- 
plied with  blood,  and  are  remarkable  for  the 
arterial  anastomoses  which  take  place  around 
them.  The  best  examples  of  these  are  met  with 
in  each  of  the  joints  of  the  extremities.  The 
parts  supplied  with  blood  are  the  synovial 
membranes,  the  ligaments,  the  fat,  and  the  extre- 
mities of  the  bones;  but  the  cartilages  cer- 
tainly do  not  receive  vessels  carrying  red 
blood  :  I  believe  there  is  no  fact  in  anatomy, 
more  generally  admitted  or  belter  determined 
than  this.  The  vascular  ramifications  which 
proceed  from  these  vessels  may  be  seen,  par- 
ticularly in  young  subjects,  advancing  in  the 
subsynovial  cellular  tissue,  and  forming  a  vas- 
cular net-work  there,  as  far  as  the  margin  of  the 
articular  cartilage  where  they  stop  abruptly; 
this  is  what  W.  Hunter  described  under  the 
name  of  circulus  articuli  vasculosus. 

Of  the  forms  and  classification  of  the  arti- 
culations.— It  is  not  difficult,  by  passing  in 
review  the  various  motions  which  take  place 
between  any  two  segments  of  a  limb,  to  form 
an  idea,  a  priori,  as  to  the  kinds  and  shapes 
of  the  articulations  by  which  these  segments 
will  be  united ;  it  is  only  necessary  not  to  lose 
sight  of  the  fact,  that  in  the  construction  of  a 
joint  regard  is  had  not  to  its  mobility  alone, 
but  to  its  security,  its  durability,  and  the  safety 
of  the  neighbouring  parts.  We  may  expect 
to  find  joints  varying  in  the  degree  of  motion, 
from  the  slightest  perceptible  quantity,  to  the 
freest  that  is  compatible  with  the  maintenance 
of  the  segments  in  their  proper  relation  with 
each  other,  and  also  in  extent  of  motion,  from 
that  which  is  so  slight  as  to  admit  of  almost 
no  appreciable  change  in  the  position  of  the 
parts,  to  that  which  allows  of  the  most  ample 
variety  of  relation  between  the  segments, 
consistent  with  the  integrity  of  the  articula- 
tion. 

It  will  appear,  then,  that  the  most  simple 
kind  of  articulation  is  that  by  which  two  parts 
are  so  united  as  that  the  slightest  appreciable 
degree  of  motion  only  shall  exist  between  them. 
This  constitutes  the  first  great  division  of  joints 
— the  Synarthrosis  (jrvv,  cum,  and  agO^ov,  arti- 
culus) — where  the  parts  are  continuous,  i.  e. 
not  separated  from  each  other  by  an  intervening 
synovial  cavity.  Some  anatomists  consider  all 
synarthrodial  joints  to  be  immoveable ;  which, 
although  not  far  from  the  truth,  cannot  be  said 
to  be  strictly  accurate.  Had  immobility  been 
the  object  to  be  obtained,  I  imagine  that  that 
might  have  been  more  effectually  accomplished 
by  the  fusion  of  the  extremities  of  the  segments 
together,  as  in  anchylosis. 

In  the  second  class  of  joints,  motion  is 
enjoyed  freely  and  fully :  this  class  is  designated 
by  the  term  Diarthrosis  ($icx,,per,  and 


the  segments  are  interrupted  completely  in 
their  continuity ;  the  extremities  of  the  bones 
can  only  be  said  to  be  contiguous. 

Synarthrosis. — The  general  characters  of  the 
articulations  belonging  to  this  class  are,  1. 
that  they  are  very  limited  in  their  motion, 
insomuch  as  to  be  considered  by  some  as  im- 
moveable ;  2.  that  their  surfaces  are  continuous, 
i.  e.  without  the  intervention  of  a  synovial 
cavity,  but  with  that  of  some  structure  different 
from  bone.  The  following  varieties  may  be 
noticed  among  synarthrodial  articulations. 

a.  Suture  (Germ.  Nath  or  Naht.  Com- 
missura  cranii,  Vesal.). — When  the  margins  of 
two  bones  exhibit  a  series  of  processes  and 
indentations  (dovetailing)  which  are  received 
and  receive  reciprocally,  with  a  very  thin  car- 
tilaginous lamina  interposed,  this  is  the  ordi- 
nary kind  of  suture,  sutura  vera,  of  which 
three  kinds  are  distinguished  :  sutura  dcntata, 
where  the  processes  are  long  and  dentiform,  as 
in  the  interparictal  suture  of  the  human  skull ; 
sutura  serrata,  when  the  indentations  and 
processes  are  small  and  fine  like  the  teeth 
of  a  saw,  as  in  the  suture  between  the  two  por- 
tions of  the  frontal  bone  ;  sutura  limbosa,  when 
there  is  along  with  the  dentated  margins  a 
degree  of  bevelling  of  one,  so  that  one  bone 
rests  on  the  other,  as  in  the  occipito-parietal 
suture. 

When  two  bones  are  in  juxta-position  by 
plane  but  rough  surfaces,  the  articulation  is 
likewise  said  to  be  by  suture,  and  this  is  the 
false  suture,  sutura  nolha,  of  which  there  are 
two  kinds  :  sutura  squamosa,  where  the  be- 
velled edge  of  one  bone  overlaps  and  rests 
upon  the  other,  as  in  the  temporo-parietal 
suture,  and  harmonia  (agu,  adapto),  where 
there  is  simple  apposition :  this  last  kind  of 
articulation  is  met  with,  as  Bichat*  observes, 
wherever  the  mechanism  of  the  parts  is  alone 
sufficient  to  maintain  them  in  their  proper 
situation,  as  may  be  seen  in  the  union  of  most 
of  the  bones  of  the  face. 

It  is  in  the  articulation  of  the  bones  of  the 
skull  and  face  of  animals,  as  has  been  already 
noticed,  that  we  see  the  best  examples  of  su- 
tures. In  the  chelonian  reptiles,  as  the  tortoise, 
the  bodies,  laminae,  and  spinous  processes  of  the 
vertebras  are  united  by  suture,  and  the  same 
mode  of  articulation  unites  the  elements  of 
the  sternum  of  the  land-tortoise  to  each  other .f 
The  bones  of  the  head  of  birds  and  fishes 
are  united  chiefly  by  the  harmonic  and  squamous 
sutures.  In  the  lateral  parts  of  the  heads  of 
fishes,  and  in  the  opercula  of  their  gills,  as 
between  the  opercular  and  subopercular  bones, 
there  is  a  species  of  articulation,  most  re- 
sembling the  squamous  suture,  but  differing 
from  it  in  admitting  a  considerable  latitude  of 
motion  by  which  these  bones  can  glide  on 
one  another.}:  To  descend  still  lower  in  the 
scale,  we  may  observe  a  mode  of  joining  very 
similar  to  suture,  between  the  tubercular  and 

*  Anat.  Gen.  t.  iii.  p.  63. 

t  See  Grant's  Comp.  Anat.  p.  83,  fig.  43. 

J  Cuvier,  Lecons  d'Anat.  Comp  t..  i.  p.  125* 


ARTICULATION. 


255 


ambulacral  plates  which  form  the  shell-like 
covering  of  the  echinida.* 

The  sutures  have  the  peculiarity  of  a  con- 
siderable tendency  to  become  obliterated  by 
age,  the  intervening  cartilage  being  ossified  ; 
it  rarely  happens  that  the  sutures  are  all  ma- 
nifest in  a  human  skull  past  fifty  years  of  age, 
and  sometimes  the  obliteration  takes  place  at 
a  much  earlier  period.  The  frontal  suture  is 
by  no  means  permanent;  it  is  not  often  found 
at  puberty.  In  birds  and  fishes  this  tendency 
to  the  obliteration  of  the  sutures  is  particularly 
manifest. 

6.  Sc/tindi/lesis  (crp£n<^yA»j0>i$,  fissio,  c^^u, 
diffindo). — This  form  of  articulation  is  where 
a  thin  plate  of  bone  is  received  into  a  space 
or  cleft  formed  by  the  separation  of  two  laminae 
of  another,  as  is  seen  in  the  insertion  of  the 
azygos  process  of  the  sphenoid  bone  into  the  fis- 
sure on  the  superior  margin  of  the  vomcr  ;  and 
in  the  articulation  of  the  lacrymal  bone  with  the 
ascending  process  of  the  superior  maxillary. 

c.  Gomphosis    (yo[AQo$,    davits.       dav<itioy 
conclavatio). — When  a  bone  is  inserted  into 
a  cavity  in  another,  as  a  nail  is  driven  into  a 
board,  or  as  a  tree  is  inserted  into  the  earth 
by  its  roots,  the  articulation  is  by  gomphosis. 
The  only  example  we  have  of  it  in  the  human 
subject  or  in  quadrupeds  is  in  the  insertion 
of  the  teeth  into  the  alveoli.     In  the  weapon 
of  offence   of  the   saw-fish   we   find   also   an 
example  in  the  manner  in  which  the   strong 
osseous  spines  are  inserted  like  teeth  into  its 
lateral  edges.      Cuvier  mentions  a  variety   of 
gomphosis,  the  only  modification  of  the  above : 
it   is   where  a  bony  process   grows   from  the 
bottom  of  the  recipient  cavity,  and  is  inserted 
into  a  cavity  in  the  base  of  the  received  bone 
or  hard  part.     This  is  the  mode  of  articulation 
of  the  nails  with   the   ungueal   phalanges  in 
animals  of  the  cat  kind ;  the  nail  is  received 
into  an   osseous   sheath,   from  the  bottom  of 
which  the  body  of  the  phalanx  projects  and 
fills  up  the  cavity  of  the  nail.     A  similar  pivot 
grows   from  the   bottom  of  the   alveoli,  into 
which  the  long  canine  teeth  of  the  walrus  are 
inserted. 

d.  Amphiarthrosis  (a/^t,   utrinquc,  a^ov, 
articulus,  i.  e.  a  mixed    form  of  articulation. 
Articulatio  dubia,  Bartholin.  Synarthrosis  diar- 
throdica). — This  is  a  form  of  articulation  where 
two  plane  or  mutually  adapted  surfaces  are  held 
together  by  a  cartilaginous  or  nbro-cartilaginous 
lamina  of  considerable  thickness,    as  well  as 
by  external  ligaments.     In  virtue  of  the  elasti- 
city of  the  interposed  cartilaginous  or  fibro- 
cartilaginous  lamina,  the  amphiarthrosis  pos- 
sesses  a   manifest,  although  certainly   a  very 
limited   degree   of   motion,    and  hence  most 
systematic  writers  class  it  with  the  diarthrodial 
articulations.     To  me  it  appears  much  more 
consistent  to  place  it  among  the  synarthrodial 
joints,  for,  1.  its  anatomical  characters  agree 
precisely  with  those  of  synarthrosis ;    2.  the 
surfaces  in  amphiarthrosis  being  continuous,  it 
would  make  an  exception  in  diarthrosis  were 

*  Meckel,  Anat.  Comp.  (Fr.  transl.)  t.  ii.  p.  43. 


we  to  place  it  there;  and,  3.  its  degree  of 
motion  is  greater  than  that  of  suture,  only 
because  of  the  greater  development  of  the  in- 
terosseous  substance.  These  points  of  similarity 
led  some  anatomists  to  call  it  Diarthrosis  syn- 
arthrodica ;  for  the  reasons  above  stated,  as 
well  as  because  it  has  one  point  of  resemblance 
to  diarthrosis  in  its  greater  latitude  of  motion, 
I  propose  the  appellation  Synarthrosis  diar- 
throdica. 

The  examples  of  this  form  of  joint  in  the 
human  body  are  the  articulation  between  the 
bodies  of  the  vertebra,  that  between  the  two 
ossa  pubis  at  what  is  called  the  symphysis,  and 
that  between  the  ilium  and  sacrum.  We 
may  also,  I  think,  place  here  the  articulation 
of  the  ribs  with  the  sternum  by  means  of  the 
costal  cartilages.*'  The  bodies  of  the  vertebrae 
in  most  of  the  mammalia  are  articulated  in 
the  same  way ;  so  are  they  in  fishes  also  ;  but 
in  these  last  there  is  a  peculiarity  already  re- 
ferred to,  which  increases  the  degree  of  motion 
of  which  the  joint  is  susceptible. f  Like  the 
sutures,  the  amphiarthrosis  is  liable  to  become 
obliterated  by  age,  and  from  the  same  cause, 
namely,  the  ossification  of  the  interosseous  la- 
mina. This  is  very  common  in  the  costo-sternal 
joints,  less  so  in  the  interpubic,  and  still  more 
rare  in  the  inter-vertebral  and  sacro-iliac. 

Diarthrosis. — Evident  mobility  is  the  dis- 
tinguishing characteristic  of  this  class  of  joints; 
the  articular  surfaces  are  contiguous,  each  co- 
vered by  a  lamina  of  cartilage  (diarthrodial 
cartilage),  having  a  synovial  sac,  and  in 
some  cases  two  synovial  sacs  interposed,, 
which  are  separated  by  a  meniscus.  The  in- 
tegrity of  the  articulation  is  maintained  by  liga- 
ments which  pass  from  the  one  bone  to  the 
other.  Their  mechanism  is  much  more  com- 
plicated than  that  of  synarthrodial  joints,  being 
intended  not  only  for  security,  but  also  to  give 
a  certain  direction  to  the  motions  of  which 
they  are  the  centre. 

Before  proceeding  to  the  enumeration  of  the 
varieties  of  joints  that  come  under  this  head,  it 
will  not  be  amiss  to  describe  briefly  the  various 
motions  which  may  take  place  between  any  two- 
segments  of  a  limb,  and  which  it  is  the  object 
of  these  joints  to  admit  of.  It  is  obvious  that 
the  most  simple  kind  of  motion  which  can  exist 
between  two  plane  or  contiguous  surfaces, is  that 
of  gliding :  one  surface  glides  over  the  other,, 
limited  by  the  ligaments  which  extend  be- 
tween the  bones.  This  motion,  however,  is  not 
confined  to  plane  surfaces,  it  may  exist  evidently 
between  contiguous  surfaces  whatever  their  form. 
When  two  segments  of  a  limb,  placed  in  a 
direct  line  or  nearly  so,  can  be  brought  to  form 

*  It  may  bo  objected  to  this  arrangement  that 
at  the  sternal  extremity  of  each  cartilage  there  is- 
a  synovial  membrane  between  it  and  the  sternal 
depression.  All  anatomists  agree  in  denying  its 
existence  at  the  articulation  of  the  first  cartilage, 
and  all  admit  the  great  difficulty  of  fully  demon- 
strating its  existence  in  the  others.  For  my  own 
part  I  do  not  believe  that  it  exists  in  any. 

t  The  articulation  of  the  lower  jaw  in  the  whale- 
bone whale,  above  referred  to,  is  a  joint  of  this 
kind. 


256 


ARTICULATION. 


zm  angle  with  each  other,  the  motion  is  that  of 
flexion,  the  restoration  to  the  direct  line  is  ex- 
tension. These  two  motions  belong  to  what 
Bichat  calls  limited  opposition ;  the  flexion  and 
extension  of  the  fore-arm  on  the  arm  illustrate 
it.  Sometimes  a  motion  of  this  kind  takes 
place  in  four  directions,  indicated  by  two  lines 
which  cut  at  right  angles.  This  is  best  under- 
stood by  a  reference  to  the  motions  which  take 
place  at  the  hip-joint :  there  it  will  be  seen 
that  the  thigh-bone  may  be  brought  forward  so 
as  to  form  an  angle  with  the  tmrik,  flexion — or 
it  may  be  restored,  extension ;  it  may  be  sepa- 
rated from  the  middle  line  of  the  body  so  as  to 
form  an  angle  with  the  lateral  surface  of  the 
trunk,  abduction — or  it  may  be  restored  and 
made  to  approximate  the  middle  line,  adduc- 
tion. Bichat  terms  this  "  opposition  vague"  It 
is  evident  that  a  joint,  which  is  suscepti- 
ble of  these  four  motions,  may  also  move  in 
directions  intermediate  to  them.  When  these 
motions  are  performed  rapidly,  one  after  the 
other,  it  appears  as  one  continuous  motion,  in 
which  the  distal  extremity  of  the  bone  describes 
a  circlfe  indicating  the  base  of  a  cone  whose 
apex  is  the  articular  extremity  moving  in  the 
joint ;  this  motion  is  called  circumduction. 

Rotation  is  simply  the  revolving  of  a  bone 
round  its  axis.  It  is  important  to  bear  this 
definition  in  mind  :  through  losing  sight  of  it 
many  anatomists  have  attributed  rotation  to  a 
joint  which  really  does  not  possess  it. 

The  varieties  of  the  diarthrodial  joint  are  as 
follows : 

a.  Arthrodia  (articulatio  plana  or  plani- 
formis.J — In  this  species  the  surfaces  are  plane 
or  one  is  slightly  concave,  and  the  other  slightly 
convex :  the  motion  is  that  of  gliding,  limited  in 
extent  and  direction  only  by  the  ligaments  of 
the  joint  or  by  some  process  or  processes  con- 
nected with  the  bones.  The  examples  in  man 
are,  the  articular  processes  of  the  vertebrae,  the 
radio-carpal,  carpal,  carpo-metacarpal,  infe- 
rior radio-ulnar,  superior  tibio-fibular,  tarsal 
and  tarso-metatarsal,  temporo-maxillary,  acro- 
mio-clavicular  and  sterno-clavicular  joints. 
This  last  articulation  and  the  wrist-joint  possess 
a  greater  latitude  of  motion  than  the  others ; 
the  former,  in  consequence  of  the  shape  of  its 
articular  surfaces:  each  surface  is  convex  in 
one  diameter  and  concave  in  the  other,  so  that 
the  gliding  that  takes  place  in  this  joint  is  in 
the  direction  of  the  long  and  short  diameters, 
which  intersect  each  other  at  right  angles.  It 
is  capable,  therefore,  of  vague  opposition  in 
those  lines,  but  certainly  not  in  the  interme- 
diate directions,  the  nature  of  the  surfaces  being 
calculated  to  prevent  this.  The  wrist  owes 
its  mobility  to  the  laxity  of  its  ligaments,  which 
permit  it  to  move  as  well  in  its  transverse  as  in 
its  antero-posterior  diameters,  as  also  in  the  in- 
termediate directions;  it  consequently  admits 
of  vague  opposition  and  circumduction.  The 
articulation  of  the  metacarpal  bone  of  the  thumb 
with  the  trapezium,  is  also  an  arthrodia  very 
similar  to  the  sterno-clavicular,  but  with  a 
greater  degree  of  motion.  Arthrodial  joints  are 
generally  provided  with  ligaments,  placed  at  the 


extremities  of  the   lines  in  the  direction  of 
which  the  gliding  motion  takes  place. 

b.  Enarthrosis(diarthrosis  orbicularis — ball- 
and-socket  joint.) — This  is  a  highly  developed 
arthrodia.     The  convex  surface  assumes  a  glo- 
bular shape,  and  the  concavity   is  so  much 
deepened  as  to  be  cup-like,  hence  the  appella- 
tion ball  and  socket.    The  ball  is  kept  in  appo- 
sition with  the  socket  by  means  of  a  capsular 
ligament,  which  is  sometimes  strengthened  by 
accessory  fibres  at  certain  parts  that  are  likely 
to  be  much  pressed  upon.     The  best  example 
of  enarthrosis  is  the  hip-joint,  and  next  to  it  the 
shoulder :  in  the  latter  the  cavity  is  but  imper- 
fectly developed.     All  the  quadrupeds  have 
their  shoulder  and  hip  joints  on  this  construc- 
tion, and  the  same  common  plan  is  observed  in 
the  vertebrata  generally  whose  extremities  are 
developed.    In  birds  and  reptiles  the  bodies  of 
the  vertebrae  are  articulated  by  enarthrosis,  and 
the   solid   calcareous  spines  on  the  external 
surface  of  the  shells  of  echinida  are  adapted  to 
round  tubercles  on  which  they  move,  thus  ex- 
hibiting a  very  complete  form  of  enarthrosis.* 

This  species  of  joint  is  capable  of  motion  of 
all  kinds,  opposition  and  circumduction  being 
the  most  perfect,  but  rotation  limited.  Indeed 
what  is  called  rotation  at  the  hip-joint,  is 
effected  by  a  gliding  of  the  head  of  the  femur 
from  before  backwards,  and  vice  versa  in  the 
acetabulum;  it  is  not  a  rotation  of  the  head 
and  neck,  but  of  the  shaft  of  the  femur. 

c.  Ginglymus  (ytyyAy/Ao?,  cardo,  articulatio 
cardiniformis,  articulation  en  charniere,  enge- 
nou}  hinge-joint.) — The  articular  surfaces   in 
the  hinge-joint    are  marked    with    elevations 
and   depressions  which  exactly  fit  into  each 
other,  so  as  to  restrict  motion  in  all  but  one 
line  of  direction.    They  are  always  provided 
with  strong  lateral   ligaments,  which  are  the 
chief  bonds  of  union  of  the  articular  surfaces. 

The  elbow  and  ankle  joints  in  man  are  per- 
fect ginglymi ;  the  knee  also  belongs  to  this 
class,  but  is  by  no  means  a  perfect  specimen, 
for  in  a  certain  position  of  the  bones  of  this 
joint,  the  ligaments  are  so  relaxed  as  to  allow  a 
slight  rotation  to  take  place.  The  phalangeal 
articulations,  both  of  the  fingers  and  toes,  are 
ginglymi.  This  form  of  joint  is  most  exten- 
sively employed  among  the  lower  animals.  In 
quadrupeds,  most  of  the  joints  of  the  extremi- 
ties come  under  this  head.  In  amphibia  and 
reptiles,  too,  there  are  many  examples  of  the 
hinge-joint.  The  bivalve  shells  of  conchiferous 
mollusca  are  united  by  a  very  perfect  hinge, 
and  a  great  number  of  the  joints  of  Crustacea 
and  insects  are  of  this  form. 

The  true  ginglymus  is  only  susceptible  of 
limited  opposition :  hence  the  knee-joint  can- 
not be  regarded  as  a  perfect  example  ;  in  fact, 
in  the  perfect  ginglymus  there  is  every  possible 
provision  against  lateral  motion. 

d.  Diarthrosis  rotatorius  (commissura  tro- 
choides.) — A  pivot  and  a  ring  constitute  the 
mechanism  of  this  form  of  joint.     The  ring  is 


*  Vide  fig.  9  in  Grant's  Comp.  Anat.  p.  21.     See 
also  the  article  ECHINODERMATA. 


ASPHYXIA. 


generally  formed  partly  of  bone  and  partly  of 
ligament,  and  sometimes  moves  on  the  pivot, 
sometimes  the  pivot  moves  in  it.  The  motion 
is  evidently  confined  to  rotation,  the  axis  of 
which  is  the  axis  of  the  pivot. 

In  the  human  subject  the  best  example  of 
this  articulation  is  that  between  the  atlas  and 
odontoid  process  of  the  axis  or  vertebra  dentata. 
The  ring  is  formed  by  a  portion  of  the  anterior 
arch  of  the  atlas,  completed  behind  by  a  trans- 
verse ligament.  Here  the  atlas  rotates  round 
the  odontoid  process,  which  is  the  axis  of  mo- 
tion. Another  example  is  the  superior  radio- 
ulnar  articulation  :  here  the  ring  is  formed  one- 
fourth  by  bone,  namely  the  lesser  sigmoid  cavity 
of  the  ulna,  and  the  remaining  three-fourths  by 
the  round  ligament  called  the  coronary  ligament 
of  the  radius.  In  this  case  there  is  rotation  as 
perfect  as  in  that  just  mentioned,  but  the  head 
of  the  radius  rolls  in  the  ring,  and  the  axis  of 
motion  is  the  axis  of  the  head  and  neck  of  the 
bone.  Some  anatomists  consider  this  joint  a 
species  of  ginglymus,  which  they  designate 
lateral. 

The  terms  Sywphysis,  Synchondrosis,  Syn- 
neurosis,  Syssarcosis,  Meningosis,  have  been 
employed  by  anatomists  to  designate  certain 
kinds  of  articulation,  chiefly  in  reference  to  the 
nature  of  the  connecting  media.  Symphysis, 
although  originally  employed  with  great  extent 
of  meaning,  seems  to  have  been  in  later  days 
applied  exclusively  to  denote  the  articulations 
of  the  pelvis,  which  we  have  classed  under 
Amphiarthrosis.  I  pass  over  the  other  terms, 
because  they  ought  to  be  discarded  from  use, 
as  only  tending  to  encumber  a  vocabulary 
already  too  much  crowded  with  difficult  and 
unnecessary  terms. 

The  descriptive  anatomy  of  the  several  joints 
will  be  found  under  the  heads — ANKLE,  CRA- 
NIUM, ELBOW,  FACE,  FOOT,  HAND,  HIP, 
KNEE,  PELVIS,  RADIO-ULNAR,  SHOULDER, 
SPINE,  TEMPORO- MAXILLARY,  TIBIO-FIBU- 
LAR,  WRIST,  and  the  morbid  anatomy  under 
the  head  JOINT. 

BIBLIOGRAPHY. — Havers,  Osteologia  nova,  8vo. 
Lond.1691.  Saltzmann,  De  Articulationibus  Artuum, 
Argent.  1712.  Walther,  De  Articulis,  Ligamentis, 
&c.  4to.  Lips.  1728.  Neumann,  Lehre  von  d. 
Articulationen  d.  mensch.  Koerpers,  Freiberg,  1745. 
Isenftamm,  Diss.  de  Ginglymo,  4to.  Erlang.  1785. 
Bonn,  De  Suturarum  co:p.  hum.  fab.  et  usu,  Lips. 
1763.  Haase,  De  unguine  articular!  ejusque  vitiis, 
4to.  Lips.  1774  ;  Ej.  De  fabrica  cartilaginum,  4to. 
Lips.  1767.  Petschel,  De  Axungia  articulari,  Lips. 
1740  (Recus.  in  Halleri  Diss.  -Anat.  select.).  Weit- 
brecht,  Syndesmologia,  4to.  Petrop.  1742  (decidedly 
the  best  work  extant  on  the  descriptive  anatomy  of 
the  ligaments).  Hunter,  W.  on  the  structure  and 
diseases  of  articulating  cartilages,  Philos.  Trans. 
1743.  Schaarschmidt,  Syndesmologische  Tabellen, 
8vo.  Lange.  1782.  Monro  on  the  Bursae  mucosae, 
fol.  Edinb.  1788.  Heysigers,  Diss.  Phys.  Anat. 
de  fabrica  intima  articulationum,  8vo.  Traj.  ad 
Rhen.  1803.  Loschae,  Die  Knochen,  &c.  des 
mensch.  Koerp.  fol.  Erlang.  1804.  Bichat,  Mem. 
sur  la  membrane  synoviale  des  articulations,  Mem. 
de  la  Soc.  Philom.  An.  6.  Dickinson,  A  syndes- 
mological  chart,  8vo.  Lond.  1821.  Cooper,  B.  on 
the  ligaments,  4to.  Lond.  1825.  Cruveilhier,  Sur 
les  cartilages  diarthrodiaux,  Arch.  Gen.  de  Med. 
Fevrier,  1824.  Bichat,  Anatomic  generate.  Beclard, 
Anatomic  generale.  (The  older  and  likewise  the 


newer  systems  of  anatomy  are  mostly  deficient  in 
syndesmology ;  the  works  of  Bichat  and  Boycr, 
however,  form  exceptions,  and  arc  well  deserving 
of  a  careful  perusal  :  the  descriptions  in  the  Traitc 
des  Maladies  Chirurgicales,  t.  iv.  of  the  latter,  are 
also  very  excellent ;  and  one  of  the  most  minute 
and  accurate  accounts  we  have  of  the  ligaments  is 
contained  in  the  magnificent  work  of  Messrs. 
Bourgery  and  Jacob,  now  in  the  course  of  publica- 
tion :  Traite  complet  de  1'anatomie  de  1'homme  ; 
Anglice,  The  whole  anatomy  of  the  human  body, 
by  R.  Willis,  fol.  Paris  and  Lond.) 

( R.  B.  Todd.) 

ASPHYXIA.  (Gr.  Acrpyfia.  Fr.  Asphixie. 
Ger.  Scheintod,  Aspliyxie.  Ital.  Asfissiaf)  The 
word  Asphyxia,  according  to  its  derivation 
(from  a,  and  <r<pv|»),  pulsus,)  ought  to  signify 
what  is  usually  expressed  by  the  term  Syncope, 
i.  e.  failure  of  the  heart's  action ;  but  it  is  now 
always  used  to  express  failure  of  the  process 
of  respiration. 

It  is  hardly  necessary  to  say,  that  there  is 
no  more  general  law  of  vital  action,  in  all 
classes  of  organized  beings,  than  its  dependence 
on  oxygen,  i.  e.  on  a  certain  chemical  action 
taking  place  between  the  nourishing  fluids  of 
that  living  body  (whether  animal  or  vegetable) 
and  the  oxygen  of  the  atmosphere.  This  law 
is,  indeed,  as  general  as  the  dependence  of 
vital  action  on  heat,  and  in  like  manner  as  a 
certain  elevation  of  temperature  (short  of  what 
acts  chemically  on  the  organized  textures)  is 
destructive  to  life,  so  a  certain  concentration 
of  oxygen  in  the  air  inhaled,  at  least  by  the 
higher  orders  of  animals,  affects  them  as  a 
poison.* 

Many  organized  substances,  as  the  seeds, 
roots,  and  stems  of  vegetables,  the  pupae  of 
insects,  eggs,  even  perfect  animals  of  some  of 
the  lower  classes,  may  retain  their  vitality, 
as  is  commonly  said,  i.  e.  remain  susceptible  of 
vital  action,  for  very  various  periods  of  time, 
at  low  temperatures,  without  exercising  any 
action  on  the  oxygen  of  the  atmosphere ;  but 
whenever  the  phenomena  indicating  vital  ac- 
tion take  place  in  them,  exposure  to  oxygen, 
and  a  certain  alteration  of  the  air  surrounding 
them,  very  soon  become  necessary  conditions 
of  the  continuance  of  vitality. 

The  alterations  which  take  place  in  the  air 
in  contact  with  different  living  bodies  are  some- 
what various.  Water  is  exhaled  probably  in 
every  instance.  In  the  case  of  some  animals, 
particularly  fishes,  there  is  certainly  an  absorp- 
tion of  azote ;  and  in  that  of  vegetables  growing 
under  the  influence  of  light,  there  is  a  decided 
absorption  of  carbon  from  the  carbonic  acid 
of  the  atmosphere,  and  an  evolution  of  pure 
oxygen.  But  it  is  now  generally  agreed,  that, 
in  all  cases,  the  action  between  the  atmosphere 
and  the  nourishing  fluid  which  is  essential  to 
the  motion  and  vivifying  power  of  the  latter, 
is  that  which  is  denoted  by  the  disappearance 
of  part  of  the  oxygen  from  the  air  that  comes 
in  contact  with  that  fluid,  and  the  substitution 
of  a  quantity  of  carbonic  acid. 

Sometime  since  it  was  the  prevalent  opinion, 
that  the  nature  of  that  action  was  merely  an 

*  See  Broughton  in  Journal  of  Science,  1830. 

s 


258 


ASPHYXIA. 


excretion  of  carbon,  which  immediately  on  its 
being  evolved  from  the  nourishing  fluid,  en- 
tered into  combination  with  the  oxygen  of  the 
air,  and  was  carried  off;  and  the  chief  reason 
for  this  opinion  was,  that  the  volume  of  oxy- 
gen which  disappeared  in  the  process,  was 
believed  to  be  just  equal,  in  all  cases,  to  that  of 
the  carbonic  acid  that  appeared.  As  it  is 
known  that  the  volume  of  any  quantity  of 
carbonic  acid  is  just  the  same  as  that  of  the 
oxygen  contained  in  that  quantity  of  acid,  if 
the  fact  had  been  as  above  stated,  the  coinci- 
dence could  hardly  have  been  accidental,  and 
the  inference  would  have  been  nearly  inevitable, 
that  the  oxygen  of  the  atmosphere  did  not  enter 
the  nourishing  fluids,  but  merely  dissolved  and 
carried  off  the  excreted  carbon. 

But  the  numerous  experiments  of  Dr.  Ed- 
wards* and  of  M.  Du  Long,-f-  seem  to  have 
nearly  established  the  proposition,  that  in  the 
respiration  of  by  far  the  greater  number  of 
animals,  the  volume  of  oxygen  that  disappears 
from,  is  somewhat  greater  than  that  of  the 
carbonic  acid  that  appears  in,  the  air  employed : 
the  same  result  was  obtained  in  experiments 
by  Allen  and  Pepys  on  birds  ;J  and  if  this  be 
so,  it  is  certain  that  the  respiration  of  these 
animals  is  attended  with  an  actual  absorption 
of  oxygen,  at  least  to  a  certain  extent. 

This  conclusion  authorizes  us  to  inquire  far- 
ther, whether  it  is  not  more  probable,  that  the 
whole  of  the  oxygen  which  disappears  from  air 
in  contact  with  the  nourishing  fluid  of  living 
beings,  is  absorbed  into  that  fluid,  and  that  the 
carbonic  acid  which  appears  is  exhaled,  ready 
formed,  in  its  place.  And  several  facts  shew 
that  this  is  by  far  the  more  probable  suppo- 
sition; and  that  oxygen  is  essential  to  vital 
action,  not  merely  as  a  means  of  carrying  off 
superfluous  carbon,  which  has  become  noxious; 
but  as  itself  an  ingredient  in  the  nourishing 
fluids,  necessary  for  the  maintenance  of  their 
motion  and  vivifying  power. 

But  without  entering  at  length  into  this 
question,  which  will  be  more  fully  discussed 
under  the  head  of  Respiration,  it  is  obvious 
from  what  has  been  said,  that  provision  must 
be  made,  in  the  ceconomy  of  all  living  beings, 
for  the  exposure  of  their  fluids  to  the  air  of  the 
atmosphere,  in  circumstances  admitting  of  ex- 
halation and  absorption  ;  and  it  may  be  farther 
stated,  that,  in  the  different  classes  of  animals, 
the  amount  of  this  mutual  action  for  which 
provision  has  to  be  made,  must  be  proportioned 
to  the  energy  and  activity  of  vital  action 
which  each  animal  is  destined  to  exhibit,  these 
qualities  being  very  generally  found  to  be 
greater,  as  the  consumption  and  vitiation  of  the 
air  are  more  rapid.§ 

These  principles  explain  the  intention  of 
many  different  contrivances  and  arrangements, 
afterwards  to  be  described,  which  are  em- 

*  De  1'Influence  des  Agens  Physiques  sur  la  Vie, 
p.  410,  et  seq. 

t  Journal  de  Physiologic,  t.  iv. 

\  See  Hodgkin's  Translation  of  Edwards,  p.  486. 

$  See  Cuvier,  La  Regne  Animale,  t.  i.  p.  56  ; 
also  Marshall  Hall,  Philosophical  Transactions, 
1832,  p.  339. 


ployed  in  different  classes  of  animals  for  the 
performance  of  the  function  of  respiration ;  and 
the  variations  of  which  may  be  said,  in  a  gene- 
ral view,  to  be  determined  by  two  conditions, 
first  by  the  medium  in  which  each  animal  is 
destined  to  exist,  and  secondly,  by  the  inten- 
sity and  variety  of  vital  actions  which  it  is  to 
be  capable  of  performing. 

The  importance,  to  all  living  beings,  of  the 
action  of  oxygen  on  their  fluids  is  most  un- 
equivocally shewn  by  the  nature  of  the  fatal 
changes  which  ensue,  when  that  action  is  in 
any  way  obstructed ;  i.  e.  by  the  nature  of  the 
changes  which  take  place  in  death  by  asphyxia. 
The  study  of  these  has  long  been  held  to  be 
of  the  highest  importance,  not  only  as  a  car- 
dinal point  in  physiology,  but  as  affording  the 
only  precise  information  in  regard  to  the  fatal 
tendency  of  many  and  various  diseases. 

It  is  chiefly  in  animals  of  the  highest  orders, 
i.  e.  in  warm-blooded  animals,  that  these  phe- 
nomena have  been  studied  ;  and  it  is  to  be 
remembered,  that  in  them  the  subject  is  ren- 
dered more  complex  by  the  higher  endow- 
ments and  greater  power  over  all  functions  of  the 
body,which  the  nervous  system  there  possesses. 
When  we  trace  the  connection,  in  these  animals, 
of  the  different  changes  that  precede  the  fatal 
event,  it  is  right  to  bear  in  mind,  that  the  in- 
terruption of  the  process  by  which  their  fluids 
are  exposed  to  the  air  is  equally  fatal,  not  only 
to  those  animals  in  which  no  action  of  the  ner- 
vous system  is  concerned  in  that  process,  but 
also  in  vegetables,  where  no  nervous  system 
exists. 

The  phenomena  of  asphyxia  in  the  higher 
animals  are  very  nearly  the  'same,  in  whatever 
manner  the  access  of  air  to  the  organs  of  respi- 
ration is  prevented.  This  may  be  done,  in  the 
case  of  animals  that  breathe  by  lungs,  in  a 
great  variety  of  ways ;  by  strangulation  or  suf- 
focation, i.  e.  by  any  mechanical  means  pro- 
hibiting the  ingress  of  air  by  the  trachea  and 
bronchi ;  by  submersion  in  water  or  any  other 
fluid ;  by  confinement  in  vacuo  or  in  such 
gases  as  contain  no  oxygen,  but  are  not  them- 
selves poisonous,  such  as  azote  and  hydrogen ; 
by  forcible  compression  of  the  thorax,  prevent- 
ing its  dilatation ;  or  by  the  admission  of  air 
into  free  contact  with  the  surface  of  the  lungs 
on  both  sides  of  the  chest,  so  as  to  prevent 
their  distension,  as  in  the  celebrated  experiment 
of  Dr.  Hooke  ;  or  by  the  section,  either  of  all 
the  separate  nerves  which  move  the  muscles 
concerned  in  the  dilatation  of  the  thorax  in 
inspiration,  or  of  the  spinal  cord  in  the  upper 
part  of  the  neck,  above  the  origin  of  the 
phrenics,  by  which  the  whole  of  these  nerves 
are  simultaneously  palsied,  as  in  many  ex- 
periments of  Galen,  Cruikshank,  Le  Gallois, 
and  others.* 

In  the  case  of  fishes  or  other  animals  that 

*  These  last  are  the  lesions  of  the  nervous  sys- 
tem which  cause  sudden  death  by  asphyxia.  Sec- 
tion of  the  par  vagum,  the  sentient  nerve  of  the 
lungs,  produces  death  by  asphyxia  also,  but 
slowly,  and  through  the  intervention  of  disease  and 
disorganization  of  the  lungs,  to  be  afterwards  no- 
ticed. 


ASPHYXIA. 


259 


breathe  by  gills,  where  several  of  the  methods 
above  enumerated  are  inapplicable,  asphyxia  is 
produced,  either  by  confinement  in  air,  or  in 
distilled  water,  or  water  impregnated  with  any 
gas  that  does  not  contain  oxygen  ;  for  no  ani- 
mal has  the  power  of  decomposing  water  by 
its  organs  of  respiration,  to  obtain  oxygen, 
and  all  aquatic  animals  are  dependent,  either 
on  the  occasional  respiration  of  atmospheric 
air  by  lungs,  or  on  the  more  constant  respira- 
tion of  the  air  contained  in  water  by  gills  or 
analogous  organs. 

In  the  case  of  fishes  breathing  by  gills,  as 
the  motion  of  these  organs  is  dependent  on 
nerves  arising  as  high  as  the  medulla  oblongata, 
injury  of  the  nervous  system  must  be  as  high 
as  that  part,  in  order  to  produce  asphyxia; 
and  on  the  other  hand,  in  the  case  of  birds, 
where  the  expansion  of  the  thorax  in  inspira- 
tion is  effected  almost  entirely  by  the  motion 
of  the  ribs,  asphyxia  may  be  produced  by 
section  of  the  spinal  cord  in  any  part  of  the 
neck.* 

We  exclude  here  entirely  the  cases,  often 
described  under  the  name  of  asphyxia,  in  which 
gases  positively  noxious  (such  as  carbonic  acid, 
carburetted  hydrogen,  &c.)  have  been  breathed, 
because  accurate  observation  shows  that  these 
are  in  fact  cases  of  poisoning,  where  the  poison 
has  been  introduced  by  the  lungs,  and  not 
simply  cases  of  asphyxia. 

The  phenomena  of  asphyxia,  in  all  the  cases 
above-mentioned,  (as  occurring  especially  in 
the  warm-blooded  animals,)  may  be  divided 
into  three  stages.  The  first  is  characterized  by 
the  intensity  of  the  sensation  which  prompts  to 
acts  of  inspiration,  and  the  consequently  violent 
and  laborious,  though  ineffectual  attempts  to 
appease  that  sensation  by  the  action  of  all 
the  muscles  of  inspiration;  and  in  some  in- 
stances by  other  actions,  voluntary  or  instinc- 
tive, but  still  under  the  guidance  of  sensibility. 
Lividity  of  the  surface  takes  place  before  the 
end  even  of  this  stage.  The  next  is  distinguished 
by  insensibility,  rapidly  increasing,  and  attend- 
ed with  irregular  spasms  or  convulsions ;  and 
the  last  by  cessation  of  all  effort,  and  of  all 
outward  signs  of  life,  while  the  heart's  action 
and  circulation  are  known  still  to  go  on  for  a 
short  time. 

In  the  case  of  a  warm-blooded  animal  (ex- 
cluding the  cetacea,and  animals  that  habitually 
dive)  in  the  full  possession  of  its  vital  powers, 
exposed  to  complete  and  sudden  obstruction  of 
the  access  of  air  to  the  lungs,  it  may  be  stated, 
that  the  two  first  of  these  stages  are  very  generally 
over  within  three  minutes,  seldom  extending  to 
five,  and  that  the  circulation  through  the  heart 
has  very  generally  ceased  within  less  than  ten 
minutes  from  the  commencement  of  the  ob- 
struction. The  time  during  which  the  priva- 
tion of  air  can  be  borne  may  be  somewhat  ex- 
tended by  habit;  and  there  are  instances  of 
men  trained  to  diving  in  India  who  have  re- 
mained under  water  three,  four,  or  even  five 
minutes  without  loss  of  sensibility  or  subse- 
quent injury. 


*  Flourens 
t.  13. 


in     Annales     d'Histoire  Nahirelle. 


In  cases  of  disease,  terminating  in  death  by 
asphyxia,  all  these  stages  may  often  be  observed 
to  be  distinctly  gone  through,  although  in  a 
very  gradual  and  somewhat  irregular  manner ; 
the  dyspnoea  and  lividity  being  succeeded  by 
delirium,  often  by  spasms,  and  ultimately  by 
coma,  and  the  respiration  coming  to  a  stand 
in  general  a  little  before  the  action  of  the 
heart. 

The  most  characteristic  appearance  which  is 
seen  after  death  by  asphyxia,  is  simply  the 
great  accumulation  of  blood  in  the  vessels  of 
the  lungs,  in  the  pulmonary  artery,  right  side 
of  the  heart,  and  great  veins,  and  the  compara- 
tively empty  state  of  the  left  side  of  the  heart, 
the  larger  pulmonary  veins,  and  the  aorta.  The 
left  ventricle  is  not  found  empty  after  death, 
but  seldom  contains  half  as  much  blood  as  the 
right;  and  it  is  in  this  part  of  the  heart  that  the 
contractions  are  soonest  observed  to  cease. 
The  accumulation  of  blood  in  the  lungs  and 
right  side  of  the  heart  is  greatest  in  cases  where 
the  asphyxia  has  been  gradual,  the  access  of 
air  to  the  blood  not  having  been  absolutely 
obstructed.* 

Besides  this  appearance  of  congestion  of 
blood  in  the  thorax,  the  liver,  the  spleen,  and 
the  whole  venous  system  in  the  abdomen,  are 
generally  observed  to  be  unusually  congested 
in  such  cases,  especially  those  parts  which  are 
depending  after  death;  and  even  ecchymosis 
on  the  mucous  membrane  of  the  stomach, 
after  strangulation,  has  been  observed  by  Dr. 
Yelloly  and  others.  This  congestion  of  blood 
in  the  liver,  and  in  the  veins  of  the  abdo- 
men, is  remarkably  observed,  and  leads  to 
important  consequences,  in  various  chronic 
diseases  of  the  thorax,  threatening  death  by 
asphyxia. 

The  blood  after  this,  as  after  other  kinds 
of  sudden  or  violent  death,  is  usually  found 
fluid,  and  very  imperfectly  coagulated ;  and  in 
connection  witli  this  state  of  the  blood  there 
are  frequently  livid  marks  resembling  ecchy- 
mosis, (though  not  depending  on  extravasation 
of  blood,)  in  various  parts  of  the  surface  of  the 
body,  and  not  exclusively  in  depending  parts. 
This  appearance  is,  of  course,  most  remarkable 
in  the  face  and  neck  after  strangulation,  and  is 
much  less  observed  on  any  part  of  the  surface 
after  drowning. 

After  strangulation,  if  the  body  is  soon  ex- 
amined, congestion  of  blood  in  the  vessels  of 
the  brain  and  pia  mater  may  often  be  remarked, 
but  there  is  seldom  any  morbid  effusion.  After 
drowning,  a  frothy  fluid,  in  consequence  of  the 
introduction  of  a  small  quantity  of  water,  and 
of  efforts  at  respiration,  is  generally  found  in 
the  trachea  and  bronchi. 

The  successive  steps  by  which  physiolo- 
gists have  been  led  to  what  we  may  regard  as 
a  satisfactory  account  of  the  phenomena  now 
described,  and  of  the  death  by  asphyxia,  may 
be  recapitulated,  as  curious  in  themselves,  and 
as  affording  the  clearest  view  of  the  evidence 
on  which  the  doctrine,  which  now  appears  to 
be  we.l  founded,  is  supported. 

*  Bichat,  Recherches  Physiologiques,  &c.  (4th 
edit.)  p.  333. 

s  2 


260 


ASPHYXIA. 


1.  The  first  opinion  on  this  subject,  which 
need  be  noticed  here,  is  that  which  was  sup- 
ported by  the  great  Haller,  viz.  that  the  circu- 
lation, and  with  it  all  other  functions  of  the 
body  are  brought  to  a  stand,  because  when  the 
movements  of  respiration  cease,  and  the  lungs 
are  no  longer  dilated  and  contracted,  there  is  a 
mechanical  difficulty  to  the  propulsion  of  the 
blood  through  the  pulmonary  capillaries,  by 
which  the  fatal  stagnation  in  these  vessels,  ob- 
vious on  dissection,  is  produced. 

This  doctrine  was  satisfactorily  refuted  by 
Goodwyn,  in  his  treatise  on  the  Connection  of 
Life  with  Respiration,  who  shewed  that  the 
air-cells  of  the  lungs  are  not  necessarily  con- 
tracted at  the  time  of  asphyxia,  and  that  after 
having  once  admitted  air,  these  cells  never  are 
so  much  emptied  of  it  again,  or  contracted  on 
themselves,  as  to  offer  any  considerable  impe- 
diment to  the  free  motion  of  blood  in  their 
parietes.  Besides,  we  know  that  the  same 
stagnation  in  the  lungs  takes  place  in  the  case 
of  an  animal  confined  in  a  gas  which  does  not 
contain  free  oxygen,  as  in  the  case  of  drowning 
or  strangulation,  although  in  the  former  case, 
any  impediment  to  the  mechanical  acts  of  re- 
spiration that  can  occur,  must  be  the  conse- 
quence, not  the  cause,  of  the  fatal  changes 
within  the  chest.* 

2.  The  well-known  theory  of  Goodwyn  him- 
self on  this  subject  was,  that  the  venous  blood 
is  not  an  adequate  stimulus  to  the  left  side  of 
the  heart,  which  in  the  natural  state  circulates 
arterial  blood  only,  and  which  fails  to  contract 
upon  or  propel  blood  which  has  passed  un- 
changed through  the  lungs.f 

This  doctrine  was,  in  its  turn,  refuted  by 
Bichat,  who  showed  by  experiment  that  in  the 
case  of  strangulation  the  venous  blood  does 
penetrate  the  lungs  and  left  side  of  the  heart, 
and  is  delivered  from  the  carotid  arteries  if 
these  are  punctured ;  that  the  appearance  of 
venous  blood  in  these  arteries  is  contemporane- 
ous with  what  was  described  as  the  second 
stage  of  asphyxia,  viz.  the  insensibility  and 
spasms ;  and  further,  his  experiments  have 
been  generally  admitted  as  affording  satisfac- 
tory evidence,  that  the  circulation  of  venous 
blood  through  the  brain  is  a  sufficient  cause  for 
these  symptoms,  and  produces  them  when  the 
venous  blood  from  the  heart  of  one  dog  is  sent 
to  the  brain  of  another.  J  He  also  found  by 
experiment,  that  venous  blood  could  be  in- 
jected artificially  into  the  left  cavities  of  the 
heart,  with  the  effect  of  exciting,  not  suppress- 
ing their  action .§ 

3.  Bichat  ascribed  the  cessation  of  the  circu- 
lation in  asphyxia,  however,  not  to  the  penetra- 
tion  of  the  brain  by  venous   blood,  and  the 
consequent  insensibility  (which   is  now    well 
known  to  be  compatible  with  the  maintenance 
of  circulation  for  many  hours,  provided   the 

*  This  point  has  been  further  elucidated  by  some 
experiments,  of  which  an  account  was  read,  by 
the  author  of  this  article,  to  the  Medical  Sections 
of  the  British  Association. 

t  Connexion  of  Life  with  Respiration,  p.  82. 

$  Recherches  Physiologiques,  &c.     Art.  vii. 

S  Ilechcrehes,  £c.  p.  327. 


blood  can  be  arterialized,)  but  to  the  penetra- 
tion of  the  muscular  substance  of  the  heart  by 
venous  blood,  sent  to  it  by  the  coronary  arte- 
ries, and  which  he  held  to  be  equally  (although 
less  rapidly)  fatal  to  the  vital  action  of  this 
organ,  as  of  the  brain  or  nerves. 

4.  Later  experiments  and  observations  have, 
however,  shewn  that  this  explanation  likewise 
is,  in  some  measure,  incorrect.  In  fact,  while 
the  free  flow  of  venous  blood  in  the  carotid 
arteries  of  an  asphyxiated  animal  was  urged 
with  perfect  fairness  by  Bichat,.  as  a  refutation 
of  the  theory  of  Goodwyn,  it  was  with  equal 
justice  argued  by  Goodwyn,*  in  opposition  to 
Bichat,  that  if  the  heart's  actions  ceased  in 
asphyxia,  only  because  its  substance  is  pene- 
trated by  venous  blood  from  the  coronary  arte- 
ries, these  actions  could  not  be  restored  by 
blowing  air  into  the  lungs  and  arterializing  the 
blood  there. 

Bichat,  indeed,  foreseeing  this  objection, 
maintained  that  the  artificial  respiration  never 
is  successful  in  restoring  the  circulation,  unless 
employed  in  the  interval  which,  as  was  already 
stated,  always  exists  between  the  occurrence  of 
insensibility  and  the  final  cessation  of  the  circu- 
lation. But  subsequent  and  careful  observa- 
tions (e.g.  those  of  lioesler,  Edinburgh  Journal, 
vol.  xxiii)  show  that  life  has  been  restored,  by 
this  means,  after  warm-blooded  animals  have 
lain  from  twelve  to  seventeen  minutes  after 
their  immersion  in  water,  i.  e.  until  a  time  when 
all  observations  made  by  laying  open  the  chests 
of  similar  animals  show  that  their  circulation 
must  have  ceased.  The  records  both  of  the 
Humane  Society  in  London  und  of  a  similar 
institution  in  Paris,  seem  sufficiently  to  show 
that  resuscitation  has  occasionally  taken  place 
in  the  human  body  after  fifteen  minutes'  im- 
mersion, f  And  we  are  therefore  well  assured 
that  the  arterialization  of  the  blood  at  the  lungs 
may,  in  some  instances,  restore  the  natural  state 
of  the  heart's  action  after  the  circulation  has 
come  to  a  stand. 

Farther,  although  there  is  a  laboured  attempt, 
by  Bichat, J  to  explain  the  accumulation  of 
blood  on  the  right  side  of  the  heart,  and  the 
comparative  emptiness  of  the  left  side,  in  as- 
phyxia, consistently  with  his  own  explanation 
of  the  failure  of  the  circulation ;  vet  it  seems 
obvious,  that  if  that  explanation  were  correct, 
the  left  side  of  the  heart,  receiving  the  venous 
blood  and  contracting  on  it  until  it  loses  its 
power  from  the  penetration  of  its  own  fibres, 
should  be  found  after  death  distended  with  that 
blood;  and  that  the  accumulation  of  blood 
taking  place  in  the  lungs  and  right  side  of  the 
heart,  indicates  that  the  capillaries  of  the  lungs 
are  the  main  seat  of  the  cause  which  ultimately 
stops  the  circulation. 

That  this  is  really  the  fact  has  been  more 
unequivocally  shown,  first,  by  the  experiments 
by  Dr.  Williams,  and  afterwards  by  those  of 

*  In  a  paper,  not  published  till  after  his  death, 
but  contained  in  the  Edin.  Med.  and  Surg.  Journal, 
July  1830. 

t  See  Cyclopaedia  of  Practical  Medicine,  art. 
Asphyxia. 

$  Kecherchcs,  &c.  art.  6. 


ASPHYXIA. 


261 


Dr.  Kay,*  which  we  know  to  hace  been  care- 
fully performed,  and  sufficiently  repeated,  and 
which  appear  to  solve  satisfactorily  all  the  diffi- 
culties that  have  been  stated.  Bichat  had  not 
adverted  to  the  length  of  time  during  which  the 
circulation  of  venous  blood  by  the  left  side  of  the 
heart,  is  carried  on  in  asphyxia ;  but  the  experi- 
ments of  both  Dr.  Williams  and  Dr.  Kay  prove, 
that  this  time  is  very  short,  and  that  before  this  side 
of  the  heart  has  lost  its  contractile  power,  the 
pulmonary  veins  luive  ceased  to  deliver  the  blood 
to  it,  in  such  quantity  as  to  maintain  any  effec- 
tive action.  A  short  quotation  from  Dr.  Kay's 
paper  wiU  show  the  evidence  for  this  propo- 
sition. 

"  Experiment  1.  The  trachea  of  a  large 
rabbit  was  tied,  the  abdomen  and  chest  opened, 
and  at  the  end  of  the  second  minute  from  the 
commencement  of  the  experiment,  the  external 
iliac  artery  was  divided ;  a  considerable 
quantity  of  dark  blood  flowed,  but  at  the 
third  minute  it  had  almost  ceased  to  escape. 
The  heart  continued  contracting  vigorously; 
very  small  quantities  of  dark  blood  collected 
slowly  every  twenty  seconds  at  the  extremity 
of  the  artery.  In  five  minutes  all  flow  of  blood 
had  entirely  ceased.  The  left  heart  contracted 
spontaneously  for  a  very  considerable  period 
longer.  I  repeated  this  experiment  with  simi- 
lar results."f  Again,  one  of  the  variations  of 
the  experiment  was  as  follows :  "  Experiment  3. 
A  rabbit  was  asphyxiated  by  tying  the  trachea. 
The  chest  was  opened.  At  the  end  of  three 
minutes  and  a  half  no  pulse  could  be  discovered 
in  the  aorta.  The  left  auricle  was  then  opened, 
the  blood  contained  escaped,  and  for  a  period 
of  from  one  to  three  minutes,  blood  occasionally 
collected  in  very  minute  quantities,  as  though 
it  gradually  drained  from  the  larger  vessels  of 
the  lungs,  but  never,  as  often  as  the  experiment 
was  repeated,  collected  in  quantity.  The  heart 
continued  vigorous  the  usual  period." 

"  In  general,"  says  Dr.  Kay,  "  the  pheno- 
mena of  the  cessation  of  motion  in  the  left  heart 
in  asphyxia  are  these.  A  smaller  quantity  of 
blood  is  received  into  its  cavities,  and  expelled 
for  zi  time  vigorously  into  the  arteries.  The 
ventricle  meanwhile  diminishes  in  size,  as  the 
quantity  of  blood  supplied  becomes  less,  until 
at  length,  although  spontaneous  contractions 
still  occur  in  its  fibres,  no  blood  issues  from  a 
divided  artery,  and  the  ventricle,  by  contrac- 
tion, has  obliterated  its  cavity.  After  this, 
blood  slowly  accumulates  in  the  auricle  from 
the  large  vessels  of  the  lungs;  and  its  con- 
tractility continues  for  a  very  considerable 
period."J 

Farther  experiments  by  Dr.  Kay  show,  that 
after  the  aorta  of  an  animal  has  been  tied,  and 
after  the  muscles  of  its  lower  extremities  have, 
in  consequence,  gradually  lost  all  contractile 
power,  that  power  is  restored  for  a  time  by  the 
injection  of  venous  blood  into  the  lower  portion 
of  the  aorta  ;§  and  from  these,  and  from  some 

*  Edinburgh  Medical  and  Surgical  Journal,  vol. 
xix.  and  xxix. 

f  Edinburgh  Journal,  vol.  xxix.  p.  42. 

t  Ibid,  p.  46. 

$  Ibid,  p.  53  and  54. 


experiments  by  Dr.  Edwards,*  we  learn,  that 
the  venous  blood,  though  less  powerful  than 
arterial  in  maintaining  the  vital  power  of  mus- 
cles, is  by  no  means  rapidly  destructive  to  it. 

The  changes  in  asphyxia,  in  the  warm-blooded 
animals,  have,  therefore,  of  late  been  generally 
thought  to  be  as  follows : — that  the  venous  blood, 
though  more  or  less  noxious  to  all  parts  of  the 
body  which  it  fully  penetrates,  is  nevertheless 
transmitted  through  thelungs  in  the  first  instance, 
in  sufficient  quantity  to  stimulate  the  left  side  of 
the  heart,  and  is  sent  from  thence  in  sufficient 
quantity  to  penetrate  the  brain; — that  by  its 
action  there  it  destroys  the  sensibility,  but  that 
it  passes  more  and  more  slowly  through  the 
pulmonary  vessels,  and  after  a  few  minutes  is 
no  longer  delivered  to  the  left  side  of  the  heart 
in  such  quantity  as  to  keep  up  regular  and 
efficient  contractions  there;  and  that  thus, 
while  the  animal  life  is  suddenly  extinguished 
by  the  noxious  influence  of  venous  blood  on 
the  brain,  the  organic  life  is  more  gradually 
brought  to  a  stand  by  its  noxious  influence  in 
the  lungs,  and  the  consequent  failure  in  the 
supply  of  blood  to  the  left  side  of  the  heart. 

This  explanation  is  consistent  with  all  the 
phenomena,  and  particularly  with  the  very 
rapid  restoration  of  the  flow  of  blood  by  the 
admission  of  air  to  the  lungs  of  half-asphyxiated 
animals,  stated  by  Bichat  himself  as  a  difficulty 
in  his  view  of  the  subject. 

The  more  recent  experiments  by  Dr.  Kay 
had,  however,  led  him  to  question  the  validity, 
even  of  that  part  of  Bichat's  doctrine,  which 
has  been  most  generally  admitted,  viz.  the  ra- 
pidly noxious  effect  of  venous  blood  on  the 
brain  and  nerves.  He  found,  in  various  cases, 
that  large  quantities  of  blood  from  the  veins  of 
one  rabbit  could  be  injected  {slowly  and  cau- 
tiously, so  as  to  avoid  all  injury  of  the  cerebral 
matter)  into  the  carotid  arteries  of  another,  with- 
out causing  more  than  muscular  debility  and 
lassitude ;  so  that  he  considers  venous  blood  to 
be  only  a  weaker  stimulus  to  the  brain  than 
arterial,  not  a  direct  poison  to  it;  and  thinks 
the  sudden  insensibility  of  asphyxia  is  to  be 
explained  by  the  rapid  diminution  of  the  quan- 
tity, not  by  the  change  of  quality,  of  the  blood 
sent  to  the  brain  from  the  heart.f 

And  when  we  bear  in  mind  the  fact  stated 
in  the  outset  of  this  inquiry,  that  the  motion 
and  vivifying  power  of  the  nutritious  fluid  is 
dependent  on  its  exposure  to  oxygen,  not  only 
in  the  higher  animals,  but  even  in  the  lowest 
tribes,  and  in  vegetables,  where  neither  heart 
nor  nervous  system  exists ;  it  appears  reasonable 
to  suppose,  that  the  chief  impediment  to  the 
blood's  motion,  from  the  failure  of  the  supply  of 
oxygen,  will  be  in  the  lungs  themselves,  where  the 
venous  blood  is  accumulated  in  the  greatest  quan^ 
tity,  and  where  all  the  minute  vessels  carrying  it 
must  be  most  completely  exposed  to  its  action, 

But  before  we  can  be  completely  satisfied 
upon  this  subject,  it  will  be  necessary  to  carry 
the  inquiry  one  step  further,  and  to  ascertain 
in  what  manner  the  change  from  venous  to 

*  De  I'lnfluencc,  &c.  p.  i.  ch.  i.  and  p.  iv.  ch.  4' 
t  Treatise  on  Asphyxia,  p.  193  et  scq. 


262 


ASPHYXIA. 


arterial  blood  so  greatly  promotes  the  flow  of 
blood  through  the  capillaries  of  the  lungs,  and 
how  the  presence  of  venous  blood  in  the  begin- 
nings of  the  pulmonary  veins  can  so  effectually 
retard  it,  that  the  action  of  the  right  ventricle  of 
the  heart,  though  continuing  vigorous  for  a 
time  thereafter,  fails  of  its  wonted  effect,  and  the 
blood  stagnates  in  those  capillaries. 

The  common  expression  employed  on  this 
subject  is,  that  arterial  blood  is  a  stimulus 
peculiarly  adapted  to  excite  the  capillaries  of 
the  lungs  and  pulmonary  veins ;  and  that 
venous  blood  stagnates  in  those  capillaries  for 
want  of  power  to  excite  them.  But  it  must 
be  remembered  that  we  have  no  distinct  evi- 
dence of  the  existence  of  coats,  still  less  of 
irritable  coats  in  the  minute  capillaries  of  the 
lungs  ;*  that  although  the  circulation  there  has 
been  often  examined  with  the  microscope,  no 
contraction  of  the  vessels  has  ever  been  ob- 
served ;  that  the  only  vital  power  of  contrac- 
tion which  experiments  authorize  us  to  ascribe  to 
any  arteries,  is  a  power  of  permanent  or  tonic 
contraction  on  their  contents,  which,  when 
called  into  action,  lasts  for  some  time,  and 
while  it  lasts  must  obviously  impede  the  flow 
of  fluids  through  these  vessels  ;  that  on  these 
grounds  Magendie  and  other  eminent  physio- 
logists believe  the  only  power,  which  arteries 
can  exercise  over  their  contents,  to  be  simply  a 
power  of  either  relaxing,  so  as  to  give  them  a  free 
passage,  or  contracting  so  as  to  lessen  and  re- 
tard their  flow  ;f  and  that,  conformably  with 
these  views,  it  was  found  by  Wedemeyer,  that 
when  he  injected  stimulating  liquids  into  the 
arteries  of  living  animals,  they  were  much 
longer  of  making  their  way  into  the  veins,  than 
mild  liquids  were.J 

These  considerations  evidently  point  to  the 
conclusion,  that,  if  the  difference  depend  on  any 
vital  action  of  vessels,  venousblood,which  makes 
its  way  so  slowly  through  the  capillaries  of  the 
lungs,  must  be  the  stronger  stimulus  to  them,  and 
that  arterial  blood,which  is  transmitted  so  readily, 
must  act  as  a  sedative,  to  the  only  vital  action 
of  which  these  vessels  are  susceptible.  But 
this  conclusion  is  again  strongly  opposed  by 
the  fact,  that  in  all  other  instances,  in  relation 
to  muscular  contraction,  to  the  functions  of 
the  nervous  system,  and  of  secreting  organs, 
arterial  blood,  and  the  oxygenated  fluids  in 
general,  manifestly  possess  the  stimulating 
power,  and  venous  blood  or  carbonized  fluids 
the  sedative. 

In  this  difficulty  it  is  important  to  remember, 
that  we  have  many  facts  to  indicate  the  exist- 
ence of  powers  which  move  the  blood  and 
other  organized  fluids  in  living  animals,  inde- 
pendently of  any  contractions  of  moving  solids. 
It  would  appear  that  the  power  by  which  any 
texture  is  nourished,  or  secretion  or  excretion  is 
formed  from  the  blood,  in  any  part  of  the  circu- 
lation, is,  to  a  certain  degree,  a  cause  of  move- 
ment of  the  blood  towards  that  part,and  that  any 
stimulus  given  to  such  act  of  nutrition  or  secre- 

*  See  Marshall  Hall  on  the  Circulation,  p.  47. 
t  Physiology,  translated  by  Milligan,-  p.  409-10. 
Mayo's  Outlines,  (2nd  edit.)  p.  87  et  seq. 

J  Edinburgh  Medical  Journal,  July  1829,  p.  90. 


tion,  although  applied  at  the  extremity  of  the 
capillaries,  produces  an  effect  on  the  circulation 
which,  as  Sir  C.  Bell  expresses  it,  is  retrograde 
along  the  branches  of  the  arteries.  Thus,  the  flow 
of  blood  to  the  mucous  membrane  of  the  stomach 
and  bowels  during  digestion,  to  the  uterus  during 
gestation,  to  the  mammse  during  lactation,  to 
any  part  of  the  body  during  inflammation,  sup- 
puration, or  the  growth  of  a  tumour,  is  excited 
by  causes  acting  at  the  extremities  of  the  arte- 
ries of  these  parts  ;  although  there  is  the  same 
difficulty  in  all  these  cases,  as  in  the  case  of  the 
lungs,  in  understanding  how  a  cause  acting 
there,  and  exciting  the  only  vital  power  which 
arteries  can  be  shewn  to  possess,  should  in- 
crease the  flow  of  blood  through  them. 

It  is  always  to  be  remembered,  that  pre- 
cisely analogous  phenomena  are  observed  from 
the  application  of  heat,  or  other  stimuli,  to 
single  branches,  or  roots,  of  vegetables,  where 
there  is  no  evidence  of  the  existence,  either 
of  a  structure  or  of  a  contractile  power,  in 
the  vessels  or  cells  through  which  the  fluids 
pass,  capable  of  giving  them  a  determinate 
direction  towards  the  parts,  "which  are  thus 
stimulated ;  and  where  the  movement  of  fluids 
that  can  be  seen,  (in  the  case  of  those  plants 
that  have  milky  juices,)  is  not  only  unattended 
with  any  visible  contraction  of  solids,  but  is 
of  a  kind,  (as  the  recent  observations  of 
Schultze,  Amici,  Raspail,  and  others  indicate,) 
which  no  contractions  of  solids  appear  capa- 
ble of  producing. 

It  is  farther  to  be  observed,  that  when  venous 
blood  becomes  arterial,  it  acquires  an  increase 
of  fibrin,*  and  that  its  tendency  to  coagulation 
is  decidedly  increased,f  which  implies  such  an 
increase  of  an  attraction  of  aggregation  in  the 
particles  of  the  fibrin,  as  may  be  held  to 
be  strictly  vital.  And  on  the  other  hand, 
when  arterial  blood  becomes  venous,  according 
to  the  microscopical  observations  of  Kalten- 
brunner,  its  globules  seem  to  separate  some- 
what from  one  another,  and  its  whole  bulk  ap- 
pears somewhat  increased.^ 

Lastly,  it  is  to  be  remembered,  that  when  a 
vessel  is  opened  in  a  living  animal,  and  the 
blood  exposed  to  the  air,  the  consequence  is, 
a  movement  of  derivation  of  the  blood,  in  all 
directions,  towards  the  aperture ;  which  is  cer- 
tainly altogether  independent  of  the  heart's 
action,  and  which  the  elaborate  investigations 
of  Haller  led  him  (and  apparently  with  good 
reason)  to  think  inexplicable  likewise  by  any 
contraction  of  vessel s.§ 

The  consideration  of  all  these  facts  may 
lead  us  strongly  to  suspect,  that  the  stimulus 
to  the  circulation  which  is  given  by  the  arte- 
rialization  of  the  blood,  and  which  we  have 
found  to  act  chiefly  in  the  capillaries  of  the 
lungs,  is  of  the  nature  of  an  attraction  of  the 
venous  blood  towards  the  part  where  it  is  to 

*  Prevost  and  Dumas,  An.  de  Chimie,  t.  xxiii. 

t  See  particularly  Schroeder  Van  der  Kolk,  Com. 
de  Sanguine  Coagulante. 

±  Experimenta  circa  Statum  Sanguinis,  &c.  §  281 
&357. 

$  Mem.  sur  le  Mouvement  du  Sang,  p.  336  et 
seq. 


ASPHYXIA. 


263 


undergo  this  change,  and  towards  the  arterial 
blood  in  advance  of  it  in  the  vessels ;  not  of 
the  nature  of  an  increased  contraction  of  the 
vessels  themsleves ;  and  that  it  is  in  conse- 
quence of  the  failure  of  this  auxiliary  power 
in  the  circulation,  that  the  stagnation  of  the 
blood  in  the  lungs  in  asphyxia,  and  the  extinc- 
tion of  the  organic  life,  are  effected. 

What  has  been  said  of  the  manner  in  which 
death  is  produced  in  asphyxia,  enables  us  to 
understand  in  what  circumstances  it  can  hap- 
pen, that  life  may  be  retained,  even  by  a 
warm-blooded  animal,  for  an  unusual  length 
of  time,  without  respiration.  As  the  stop  to 
the  circulation  is  the  immediate  cause  of  death, 
it  is  obvious  that  an  animal  which  can  exist  for 
a  time,  in  a  lowered  state  of  vitality,  with 
little  or  no  circulation,  will  during  that  time 
require  no  exposure  of  its  blood  to  air,  to 
maintain  that  grade  of  vitality ;  and  farther 
that  in  such  an  animal,  as  the  brain  will  not 
suffer  from  the  afflux  of  venous  blood,  and  as 
the  lungs  will  not  be  hurtfully  congested,  these 
organs  will  retain  a  condition  much  better 
adapted  for  the  recovery  of  their  functions, 
than  they  will  in  those  cases  where  asphyxia 
is  produced  at  a  time  when  the  circulation  is 
vigorous. 

Hence  we  can  easily  understand,  that  per- 
sons who  are  in  a  state  of  syncope,  (from  a 
temporary  cause,)  in  whom  the  circulation  is 
nearly  at  a  stand  before  the  access  of  air  to 
their  lungs  is  obstructed,  may  survive  a  longer 
suspension  of  the  acts  of  respiration  than  per- 
sons in  health.  This  has  been  stated,  by  Des 
Granges  and  Fodere,  as  the  explanation  of 
some  cases  in  which  it  appears  certain,  that 
recovery  has  taken  place  after  fifteen  minutes 
or  more  of  submersion  in  water.* 

The  case  of  hybernating  animals  was,  until 
lately,  considered  to  be  of  this  nature,  i.  e.  it 
was  supposed  that  circulation  is  gradually  sus- 
pended in  those  animals,  simultaneously  with 
respiration,  and  therefore  that  such  animals, 
although  consuming  little  or  no  air,  did  not 
suffer  the  noxious  influence  of  venous  blood 
on  their  solids,  and  remained  susceptible  even 
of  sensation.  But  the  experiments  of  Dr. 
Marshall  Hall  f  appear  to  have  established  that 
in  warm-blooded  hybernating  animals  in  the 
complete  state  of  torpor,  when  respiration  is 
quite  at  a  stand  for  many  hours,  circulation, 
although  slow  and  feeble,  still  goes  on  regu- 
larly; so  that  we  must  suppose  the  essential 
peculiarity  of  these  animals,  during  the  state 
of  lowered  vitality,  to  which  they  are  reduced 
by  cold,  to  be  this,  that  the  venous  blood  has 
little  of  the  noxious  effect,  in  any  part  of  the 
system,  which  it  has,  on  them  as  on  other 
animals,  during  the  state  of  activity  ;  it  has 
neither  the  same  difficulty  of  making  its  way 
through  the  lungs,  nor  the  same  destructive 
influence  on  the  brain.  J 

*  Fodere,  Med.  Legale,  $  613. 

t  Phil.  Transactions,  1832. 

$  Dr.  M.  Hall  considers  the  essential  peculiarity 
of  these  animals  to  be,  that  the  left  side  of  the 
heart  in  them,  is  irritable  by  venous  blood  ;  but  as 
it  appears  from  the  facts  above  stated,  that  the 


The  nearest  approach  to  this  mode  of  vita- 
lity in  the  human  body,  is  in  the  case  of  the 
new-born  child,  which  has  never  felt  the  in- 
fluence of  perfectly  arterial  blood,  and  which 
has  been  known  to  live,  although  its  natural 
respiration  was  not  established  for  nearly  an 
hour  after  birth. 

The  study  of  the  fatal  changes  in  asphyxia 
is  also  of  peculiar  importance  as  illustrating 
the  manner  in  which  the  circulation,  and  the 
organic  functions  maintained  by  it,  are  con- 
nected with  the  nervous  system.  It  will  be 
observed,  that  as  the  vitality  of  hybernating 
animals,  during  the  state  of  torpor,  is  inde- 
pendent of  respiration,  so  it  is  also,  in  a  great 
measure  at  least,  independent  of  the  larger 
masses  of  the  nervous  system  ;  and  Dr.  M. 
Hall  found,  by  experiment  in  a  hedgehog  in 
this  state,  that  the  circulation  went  on  regu- 
larly for  ten  hours  after  the  gradual  but  com- 
plete destruction  of  the  brain  and  spinal  cord. 

Indeed,  the  maintenance   of  the  circulation 
after  the  head  of  an  animal  has  been  cut  off, 
by   the  artificial   respiration,  i.  e.  by  inflating 
its   lungs   in  a  manner  resembling  its  natural 
breathing,  (which  has  been  so  often  practised 
by  Fontana,  Cruikshanks,  Bichat,  Brodie,  Le 
Gallois,  Wilson  Philip,  and  others,)  is  in  it- 
self  a  clear  proof  that  the  circulation,  and 
other   functions    of  organic   life*  in   animals, 
are  necessarily  and  immediately  dependent  on 
the  animal  life,  only  inasmuch  as  the  natural 
respiration  of  animals,  and  the  arterialization  of 
their  blood,  are  dependent  on  sensation.  And  ac- 
cordingly we  know,  that  in  that  stage  of  animal 
existence,    where    the    supply    of   sufficiently 
arterialized  blood  is  provided  for  without  the 
intervention  of  sensation,  i.e.  in  the  foetus  in 
utero,  the  whole  organic  life  is  altogether  in- 
dependent of  the  animal,  and  goes  on  perfectly, 
not  only  before  sensation  is  felt,  but  even  in 
cases  where  the  essential  organs  of  sensation 
and  of  voluntary  motion,  the  brain  and  spinal 
cord,  do  not  exist.     It  is  not  until  the  moment 
of  birth,  when  the  arterialization  of  the  blood 
is  put  in  dependence  on  sensation, — that  the 
brain  and  spinal  cord  become  essential  for  the 
maintenance  of  organic  life ;  or  that  we  possess 
any  proof  of  influence  being  exercised  by  the 
nervous  system,  over  that  part  of  the  animal 
ceconomy. 

It  seems  probable,  that  if  we  possessed  the 
means  of  making  the  artificial  respiration  ex- 
actly similar  to  the  natural,  and  neither  injuring 
the  structure  of  the  lungs,  nor  introducing 
more  air  into  them  than  is  useful,  in  practising 
it,  the  circulation,  and  perhaps  all  the  func- 
tions of  organic  life,  might  be  maintained,  after 
the  head  of  an  animal  is  cut  off,  until  nearly 
the  time  when  it  must  fail  for  want  of  nourish- 
ment; but  it  must  also  be  remembered,  that 
in  the  adult  animal,  as  the  experiments  of  Le 

stop  to  the  circulation  in  asphyxia  is  at  the  lungs, 
the  chief  peculiarity  of  these  animals  must  lie 
there  also. 

*  By  organic  life,  we  mean  those  vital  acts  which 
take  place  without  the  intervention  or  consciousness 
of  the  mind  ;  by  animal  life,  those  in  which  some 
mental  act  is  an  essential  constituent. 


264 


ASPHYXIA. 


Gallois,  Dr.  Wilson  Philip,  Flourens,  and 
others  have  shewn,  injuries  of  the  brain  and 
spinal  cord,  (particularly  injuries  suddenly  in- 
flicted on  any  large  portions  of  these  organs,) 
may  directly  influence,  or  even  wholly  sup- 
press, vital  actions  belonging  to  the  head  of 
organic  life,  for  the  performance  of  which  we 
have  no  evidence  of  their  furnishing  any  ne- 
cessary condition. 

As  the  function  of  respiration  thus  appears 
to  be  the  only  link  by  which  the  organic  life 
is  immediately  and  necessarily  connected  with 
animal  life,  it  is  naturally  to  be  expected  that 
the  extinction  of  animal  life  should  affect  the 
organic  functions  just  in  the  same  way  as  the 
suspension  of  respiration  does,  and  therefore 
that  in  the  case  of  death  beginning  at  the 
brain,  as  Bichat  expressed  it,  (i.  e.  of  death 
consequent  on  the  extinction  of  sensation  and 
voluntary  motion,)  the  circulation  and  other 
organic  functions  should  be  brought  to  a  stand 
just  in  the  same  manner  as  in  death  by  as- 
phyxia. And  in  what  is  strictly  called  death  by 
coma,  this  is  really  the  case;  the  sensations  being 
gradually  more  and  more  impaired,  the  sense 
of  anxiety  in  the  chest,  which  prompts  to  the 
acts  of  respiration,  is  ultimately  extinguished  ; 
but  even  after  the  last  breath  has  been  drawn, 
the  pulsations  of  the  heart  still  continue,  and 
the  blood  then  gradually  stagnates  in  the  lungs, 
the  circulation  comes  to  a  stand,  and  the  blood 
is  found  after  death  congested  on  the  right  side 
of  the  heart,  just  as  in  the  case  of  asphyxia 
already  described. 

That  this  is  truly  the  mode  of  fatal  termina- 
tion in  cases  where  death  takes  place  strictly 
in  the  way  of  coma,  was  first  unequivocally 
proved  by  Sir  B.  Brodie,*  who  found,  by  experi- 
ment, that  animals  poisoned  by  opium  or 
other  narcotics,  and  in  which  the  acts  of  re- 
spiration had  ceased,  in  consequence  of  the 
impression  made  on  the  brain  and  the  gradu- 
ally increasing  insensibility,  might  be  recovered 
by  the  artificial  respiration,  just  as  asphyxiated 
animals  may  be.  Indeed  the  same  expedient 
had  been  previously  employed  with  success 
(although  not  suggested  by  an  equally  accurate 
view  of  its  mode  of  action)  by  Mr.  Whately.f 

The  reason  why  the  same  expedient  cannot 
be  expected  to  avail  in  cases  of  disease  termi- 
nating by  coma  is  simply  that  in  these  cases 
the  cause  of  the  coma  is  not  temporary,  like 
the  effect  of  a  narcotic  poison,  but  permanent. 
It  seems  possible  that  it  may  yet  be  found 
successful  in  some  cases  of  insensibility  with 
convulsion,  in  children,  unconnected  with  or- 
ganic lesion. 

In  so  far,  therefore,  as  the  extinction  of  the 
organic  life  is  concerned,  the  death  by  coma, 
or  beginning  at  the  brain,  resolves  itself  into  the 
death  by  asphyxia,  or  beginning  at  the  lungs, 
the  difference  lying  merely  in  the  mode  in 
which  the  arterialization  of  the  blood  is  ar- 
rested. 

But  although  this  is  strictly  true  as  to  cases 


*  Phil.  Transactions,  1812. 

t  London  Medical  Observations   and   Inquiries, 
vol.  vi. 


of  violent  death,  produced  experimentally  in 
such  a  way  that  a  single  cause  only  is  allowed 
to  operate  ;  and  although  we  occasionally  meet 
with  cases  of  equal  simplicity  in  disease,  and 
ought  always  to  keep  in  view  the  principles 
which  these  simple  cases  illustrate  in  the  treat- 
ment of  disease,  yet  it  ought  not  to  be  sup- 
posed that  either  the  death  by  asphyxia,  that 
by  coma,  or  that  by  syncope,  often  present 
themselves  to  the  observation  of  the  medical 
practitioner  in  the  same  simplicity  as  to  the 
experimental  physiologist.  We  can  state  from 
frequent  observation,  that  it  is  only  in  a  certain 
number  of  cases  of  disease,  strictly  belonging 
to  the  head,  such  as  apoplexy  or  hydrocephalus, 
that  death  takes  place  exactly  in  the  way  of 
coma,  as  above  described,  or  that  the  function 
of  circulation  can  be  observed  to  survive  that 
of  respiration ;  and  on  the  other  hand  there 
are  many  instances  of  disease  of  the  lungs, 
particularly  of  phthisis,  in  which  the  ultimate 
extinction  of  life  is  rather  in  the  way  of  syncope 
than  of  asphyxia.  The  simple  principle,  that 
the  circulation,  though  not  dependent  on  any 
action  of  the  nervous  system,  is  liable  to  be 
influenced  in  various  ways  by  causes  acting 
on  the  nervous  system,  enables  us  to  under- 
stand that  death  may  often  take  place,  in  the 
course  of  diseases,  in  a  way  different  from  that 
which  the  seat  of  the  disease  may  lead  us  to 
anticipate. 

Nevertheless  it  may  often  be  of  real  and 
practical  importance,  with  the  view  of  ac- 
quiring clear  and  precise  ideas  of  the  modes 
of  fatal  termination  which  are  to  be  expected 
in  the  course  of  diseases,  and  particularly  of 
such  diseases  as  fever — where  the  symptoms 
immediately  preceding  death,  and  the  causes 
evidently  inducing  death,  are  remarkably  various 
in  different  individual  cases, — to  study  atten- 
tively the  phenomena,  and  causes,  of  the 
fatal  termination,  in  the  simpler  cases  of  violent 
death,  such  as  those  which  have  been  here 
considered. 


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de  la  mort  des  noyes,  8vo.  Lyon.  1768.  Du  Cheinin 
d'Etang,  Mem.  sur  la  cause  de  la  mort  des  noyes  : 
reponse  a  MM.  Champeaux  et  Faisole,  8vo.  Paris, 


AVES. 


26,3 


1770.  Fothergill,  New  inquiry  into  the  suspension 
of  vital  action,  &c.  8vo.  Lond.  1795.  Caillau, 
Mem.  sur  1'asphyxic  par  submersion,  8vo.  Bordeaux, 
1799.  Fine,  De  la  submersion,  4to.  Paris,  1805. 
Berger,  Essai  sur  la  cause  de  1'asphyxie  par  sub- 
mersion, 4to.  Paris,  1805.  Pltnicqiiet,  Animadvers. 
in  statum  ac  therap.  submersorum,  4to.  Tubing. 
1799.  Hunter,  Animal  reconomy,  4to.  Leroy, 
Rechcrches  sur  les  asphyxies,  8vo.  Paris,  1829. 
Devergie,  Diet,  de  Med.  et  Chir.  Prat.,  art.  As- 
phyxie.  Ktxjet,  in  Cyclopaedia  of  Practical  Medi- 
cine, art.  Asphyxia.  Kay,  on  asphyxia,  8vo.  Lond. 
1834  (the  most  complete  and  able  work  on  this  subj  ct 
in  the  JKnyliy/i  language).  Edwards,  Sur  1'influence 
des  agens  physiques,  Englished  by  Drs.  Hodgkin 
and  Lister,  Appendix,  p.  463. 

(W.  P.  Alison.) 


AVES,  birds;  (Gr.  O§»»0«?;  Fr.  Oiseaux ; 
Germ.  Vogcln;  Ital.  Uccelli:)  a  class  of  ovi- 
parous vertebrate  animals,  with  warm  blood, 
a  double  circulation,  and  a  covering  of  feathers. 

Birds  are  organized  for  flight,  and  as  this, 
the  most  vigorous  kind  of  locomotion,  demands 
the  greatest  energy  in  the  contractility  of  the 
muscular  fibre,  so  the  respiratory  function  finds 
its  highest  development  in  the  present  class. 
Not  only  the  ramifications  of  the  pulmonary 
artery,  but  many  of  the  capillaries  of  the  sys- 
temic circulation,  from  the  singular  extension 
of  the  air-cells  through  the  body,  are  sub- 
mitted to  the  influence  of  the  atmosphere,  and 
hence  birds  may  be  said  to  enjoy  a  double  re- 
spiration. 

Although  the  heart  resembles  in  some  parti- 
culars that  of  the  Reptilia,  the  four  cavities  are 
as  distinct  as  in  the  Mammalia,  but  they  are 
relatively  stronger,  their  valvular  mechanism  is 
more  perfect,  and  the  contractions  of  this  organ 
are  more  forcible  and  frequent  in  Birds  in  ac- 
cordance with  their  more  extended  respiration 
and  their  more  energetic  muscular  actions. 

As  Birds  exceed  Mammals  in  the  activity 
of  those  functions  on  which  the  waste  and 
renovation  of  the  general  system  more  imme- 
diately depend,  so  they  possess  a  higher  stan- 
dard of  animal  heat :  their  ordinary  tempera- 
ture is  103°  and  104°,  and  according  to  Cam- 
per is  occasionally  as  high  as  107°  Fahr. 

The  modification  of  the  tegumentary  cover- 
ing characteristic  of  the  present  class  is  to  be 
regarded  rather  as  dependent  upon,  than  oc- 
casioning, this  high  degree  of  internal  tem- 
perature, which  requires  for  its  due  mainte- 
nance against  the  agency  of  external  cold  an 
adequate  protection  of  the  surface  of  the  body 
by  means  of  non-conducting  down  and  imbri- 
cated feathers ;  and  this  warm  clothing  is  more 
especially  required  to  meet  the  sudden  vari- 
ations of  temperature  to  which  the  bird  is 
exposed  during  its  rapid  and  extensive  flights. 

The  generative  product  is  always  excluded 
from  the  oviduct  in  an  undeveloped  state,  in- 
closed, in  a  liquid  form,  within  a  calcareous 
case  or  shell.  The  female  organs  are,  therefore, 
developed  only  on  the  left  side  of  the  body. 
The  ovum  is  subsequently  perfected  by  means 
of  incubation,  for  which  action  the  bird  is  es- 
pecially adapted  by  its  high  degree  of  animal 
heat. 

Birds  form  the  best  characterized,  most  dis- 


tinct, and  natural  class  in  the  whole  animal 
kingdom,  perhaps  even  in  or  ganic  nature 
They  present  a  constancy  in  their  mode  of 
generation  and  in  their  tegumen  tary  covering, 
which  is  not  met  with  in  any  other  of  the 
vertebrate  classes.  No  species  of  Bird  ever 
deviates,  like  the  Cetacea  among  Mammals, 
the  Serpents  among  Reptiles,  and  the  Eels 
among  Fishes,  from  the  tetrapodous  type  of 
formation  which  so  peculiarly  characterizes  the 
vertebrate  division  of  animals. 

The  anterior  extremities  are  invariably  con- 
structed according  to  that  plan  which  best  adapts 
them  for  the  actions  of  flight ;  and  although,  in 
some  few  instances,  the  development  of  the 
wings  proceeds  not  so  far  as  to  enable  them  to 
act  upon  the  surrounding  atmosphere  with  suffi- 
cient power  to  overcome  the  counteracting 
force  of  gravity ;  yet,  in  these  cases  they  assist, 
by  analogous  motions,  the  posterior  extremities; 
either,  as  in  the  Ostrich,  by  beating  the  air 
while  the  body  is  carried  swiftly  forward  by  the 
action  of  the  powerful  legs ;  or,  as  in  the  Pen- 
guin, by  striking  the  water  after  the  manner  of 
fins,  and  by  the  resistance  of  the  denser  me- 
dium carrying  the  body  through  the  water  in  a 
manner  analogous  to  that  by  which  the  birds 
of  flight  are  borne  through  the  air.  In  a  few 
exceptions  only  are  the  wings  reduced  to  mere 
weapons  of  offence,  as  in  the  Cassowary  and  in 
the  singular  Apteryx  of  New  Zealand,  in  which 
they  are  represented  by  a  single  spur.  In  no 
instance  do  the  anterior  extremities  take  any 
share  in  stationary  support  or  in  prehension. 

Birds  are  therefore  biped,  and  the  ope- 
rations of  taking  the  food,  cleansing  the 
plumage,  &c.  are  almost  exclusively  performed 
by  means  of  the  mouth,  which  consists  of  two 
unlabiate  and  edentate  mandibles,  sheathed 
with  horn.  To  facilitate  the  prehensile  and 
other  actions  thus  transferred  to  the  head,  the 
neck  is  elongated,  and  the  body  generally  in- 
clined forwards  and  downwards  from  the  hip- 
joints.  The  thighs  are  accordingly  extended 
forwards  at  an  acute  angle  from  the  pelvis  to- 
wards the  centre  of  the  trunk,  and  the  toes  are 
lengthened  and  spread  out  to  form  an  adequate 
base  of  support.  The  actions  of  perching, 
walking,  running,  scratching,  burrowing,  wa- 
ding, and  swimming,  require  for  their  perfect 
performance  different  modifications  of  the  pos- 
terior extremities.  The  mandibles,  again,  present 
as  many  varieties  of  form,  each  corresponding  to 
the  nature  of  the  food,  and  in  some  degree  in- 
dicative of  the  organization  necessary  for  its 
due  assimilation.  Ornithologists  have,  there- 
fore, founded  their  divisions  of  the  class  chiefly 
on  the  modifications  of  the  bill  and  feet.  Since, 
however,  Birds  in  general  are  associated  to- 
gether by  characters  so  peculiar,  definite,  and 
unvarying,  it  becomes  in  consequence  more 
difficult  to  separate  them  into  subordinate 
groups,  and  these  are  necessarily  more  arbi- 
trary and  artificial  than  are  those  of  the  other 
vertebrate  classes. 

A  binary  division  of  the  class  may  be  found- 
ed on  the  condition  of  the  newly-hatched 
young,  which  in  some  orders  are  able  to  run 
about  and  provide  food  for  themselves  the  mo- 


266 


AVES. 


ment  they  quit  the  shell  (Aves  pr&coces) ; 
while  in  others  the  young  are  excluded  feeble, 
naked,  and  blind,  and  dependent  on  their  pa- 
rents for  support  (Aves  altrices). 

SCOPOLI,  in  his  *  Introduction  to  Natural 
History,'  published  in  1777,  proposed  a  dicho- 
tomous  systematic  distribution  of  Birds,  found- 
ed on  the  form  of  the  scales  covering  the 
tarsus.  The  species  which  have  these  scales 
small  and  polygonal  are  the  Retepedes  of  this 
author;  those  which  have  the  legs  covered 
anteriorly  with  unequal  semicircular  plates  are 
the  Scutipedes. 

NITZSCH,*  the  celebrated  professor  of  natural 
history  at  Halle,  has  synthetically  grouped  to- 
gether the  feathered  tribes  under  three  grand 
orders,  according  to  the  great  divisions  of  the 
terraqueous  globe  which  form  the  principal 
theatres  of  their  actions.f  The  first  order  con- 
sists of  the  birds  of  the  air  par  excellence,  Aves 
aerea  (Luft-vogeln) ;  the  second  order  em- 
braces the  birds  of  the  earth,  Aves  terrestres 
(Erd-vogeln)  ;  the  third  great  division  includes 
the  birds  which  frequent  the  waters,  Aves  aqua- 
tics (Wasser-vogeln).  The  Eagle  and  the 
Sparrow  may  be  named  as  examples  of  the  first ; 
the  Ostrich  and  the  common  fowl  of  the 
second ;  the  Heron  and  the  Gull  of  the  third 
of  these  extensive  divisions. 

A  more  definite  arrangement  of  Birds,  in 
which  a  similar  principle  may  be  traced,  has 
been  proposed  by  a  distinguished  naturalist  of 
our  own  country,  Mr.  VIGORS.  He  divides  the 
class  Aves  intone  orders.  The  first  includes 
the  birds  which  soar  in  the  upper  regions  of  the 
air,  which  build  their  nests  and  rear  their 
young  on  the  highest  rocks  and  loftiest  trees, 
and  which  may  be  regarded  as  the  typical 
species  of  Nitzsch's  Aerial  Birds;  this  order  is 
termed  Raptores,  from  the  rapacious  habits 
and  animal  food  of  the  species  so  grouped  to- 
gether. 

The  second  order  affects  the  lower  regions  of 
the  air ;  the  birds  composing  it  are  peculiarly 
arboreal  in  their  habits,  and  are  therefore  term- 
ed Perchers  or  Insessores. 

The  third  order  corresponds  to  Nitzsch's 
Aves  terrestres,  and  is  denominated  Rasores, 
from  the  general  habit  which  these  granivorous 
species  present  of  scratching  up  the  soil  to 
obtain  their  food. 

By  dividing  the  aquatic  birds  of  Nitzsch  into 
those  which  frequent  the  fresh  waters,  and  are 
limited  to  wading  into  rivers,  lakes,  &c.  in 
search  of  their  food,  and  those  which  possess  the 
power  of  swimming  in  the  great  ocean,  we  ob- 
tain the  two  remaining  orders  of  the  quinary 
arrangement  of  Mr.  Vigors,  viz.  the  Grallatores, 
or  Waders,  and  the  Natatores,  or  Swimmers. 
The  merit  of  this  system  is  not,  however, 
confined  to  the  defining  of  the  different  groups 
in  as  clear  and  readily  appreciable  a  manner  as 
the  subject  will  admit;  but  it  also  aims  at 

*  See  Schoepfs,  in  Mechel's  Archiv  fur  Physio- 
logic, B.  12,  p.  73. 

t  Blumenbach  more  vaguely  proposes  a  Binary 
arrangement  of  Birds  on  the  same  principle  ;  he 
divides  the  class  into  Land- Birds  and  Water- Birds. 
In  Lawrence's  Blumenbach,  Corny.  Anat.  p.  xxxiii. 


displaying  the  natural  affinities  by  which  the 
several  orders  and  families  are  connected  with 
and  pass  into  one  another.  In  the  ornitholo- 
gical systems  of  other  naturalists,  who  have 
made  this  branch  of  zoology  their  particular 
study,  we  find  the  greatest  discrepancy  both  as 
to  the  number  and  value  of  the  primary  divi- 
sions of  the  class. 

Sandewall  lias  four  orders  or  cohorts. 

Vieillot,  like  Vigors,  has  five  orders. 

Linnaeus,  Cuvier,  Carus,  and  Dumeril  have 
six  orders. 

Illiger  has  seven. 

Scopoli,  Latham,  Meyer,  Wolf  and  Blain- 
ville  have  nine. 

Temminck  (1820)  has  sixteen. 

Schreffer  has  seventeen. 

Brisson  has  twenty-eight,  and 

Lacepede  has  thirty-eight  orders. 

Where  so  many  masters  of  the  science  differ, 
it  is  difficult  for  one  less  profoundly  versed  in 
ornithology  to  select  the  most  unexceptionable 
system  of  arrangement,  and  as  Km  BY*  ob- 
serves, '  the  choice  perplexes.'  We  have  here 
adopted  the  arrangement  proposed  by  that  dis- 
tinguished naturalist  as  being  the  one  which 
facilitates  the  expression  of  the  leading  ana- 
tomical differences  which  obtain  in  the  class  of 
Birds,  and  which  may  therefore  be  considered 
as  the  most  natural. 

ORDERS. 

I.  RAPTORES,  Vig.   Syn.  Accipitres,  Linn. 
Cuv.  Birds  of  Prey  or  Raveners.f 

II.  INSESSORES,  Vig.  Passeres,  Linn.  Cuv. 
Perchers. 

III.  SCANSORES,  Illig.  Cuv.  Climbers. 

IV.  RASORES,  Illig.  Gallina,  Cuv.  Scratchers. 
V.  CURSORES,     Illig.     Brevipennes,     Cuv. 

Coursers. 
VI.  GRALLATORES,  Illig.  Gralla,  Linn.  Cuv. 

Waders. 
VII.  NATATORES,     Illig.   Palmipedes,    Cuv.; 

Anseres,  Linn.  Swimmers. 
The  following  are  the  characters  of  these  orders. 

Class  AVES  (Birds.) 
Animal  vertebrated,  oviparous,  biped. 
Anterior  extremities  organized  for  flight. 
Integument  plumose. 
Blood,  red,  warm. 
Respiration  and  circulation  double. 
Lungs  fixed,  perforated. 
Negative  characters,  no  auricles,  lips,  teeth, 
epiglottis,  diaphragm,  fornix,  corpus  callosum, 
scrotum. 

Order  I.  RAPTORES. 

Body,  very  muscular. 


Fig.  112. 


Beak,  strong,  cur- 
ved, sharp-edged  and 
sharp-pointed,  often 
armed  with  a  lateral 
tooth;  upper  man- 
dible the  longest. 
(Fig  112.) 


*  Bridgewater  Treatise,  vol.  ii.  p.  444. 

f  This  word  is  proposed  by  Mr.  Kirby  as  the 
English  for  Raptores ;  it  is  the  substantive  of  rave- 
nous, from  the  verb  to  raven. 


AVES. 


267 


-/>£*,     robust,  Fig.  113. 

short,  with  three 
toes  before,  and 
one  behind  ;  all 
armed  with  long, 
strong,  crooked 
talons.  Fig.  1 13. 

All  the  Birds 
of  Prey  feed  on 
the  flesh  of  living 
or  recently  killed 
animals.  They 
have  a  prompt, 
powerful,  and  rapid  flight.  They  are  mono- 
gamous; the  female  exceeds  the  male  in  size. 
They  nidificate  in  lofty  situations  and  rarely 
lay  more  than  four  eggs :  the  young  are  ex- 
cluded in  a  blind  and  feeble  state. 

The  Birds  of  Prey  are  either  diurnal  or  noc- 
turnal. 

The  Diurnal  Raptores  have  their  eyes  di- 
rected laterally,  and  are  divided  into  the  fol- 
lowing families — Falconidte,  Eaglesand  Hawks ; 
Vulturidte,  Vultures;  and  Gypogeranida',\vh\ch 
includes  the  Secretary  vulture.  In  the  first  two 
divisions  the  characters  of  the  order  are  most 
strongly  marked  ;  in  the  third  the  legs  deviate 
from  the  ordinal  character  and  are  remarkably 
elongated,  adapting  it  to  an  inferior  kind  of 
grey,  viz.  noxious  reptiles,  serpents,  &c. 

The  Nocturnal  Raptores  have  the  eyes  directed 
forwards,  and  include  the  Strigidte  or  owl-tribe. 

Order  II.  INSESSORES. 

Legs  slender,  short,  with  three  toes  before 
and  one  behind,  the  two  external  toes  united 
by  a  very  short  membrane.* 

The  Perchcrs  form  by  far  the  most  nume- 
rous order  of  birds,  but  are  the  least  easily 
recognizable  by  distinctive  characters  common 
to  the  whole  group.  Their  feet,  being  more 
especially  adapted  to  the  delicate  labours  of 
modification,  have  neither  the  webbed  struc- 
ture of  those  of  the  Swimmers,  nor  the 
robust  strength  and  destructive  talons  which 
characterise  the  feet  of  the  Bird  of  Rapine, 
nor  yet  the  extended  toes  which  enable  the 
Wader  to  walk  safely  over  marshy  soils  and 
tread  lightly  on  the  float- 
ing leaves  of  aquatic 
plants ;  but  the  toes  are 
slender,  flexible,  and 
moderately  elongated 
with  long,  pointed  and 
slightly  curved  claws. 
(Fig.  114.) 

The  perchers  in  general  have  the  females 
smaller  and  less  brilliant  in  their  plumage  than 
the  males ;  they  always  live  in  pairs,  build  in 
trees,  and  display  the  greatest  art  in  the  con- 
struction of  their  nests.  The  young  are  ex- 
cluded in  a  blind  and  naked  state,  and  wholly 
dependent  for  subsistence  during  a  certain 

*  The  genus  Ceyr,  Lacep.  ( Akedo  tridactyla, 
Pall.)  affords  an  exception,  the  inner  toe  being 
deficient;  and  the  two  other  anterior  ones  being 
united  as  in  the  other  Syndactyles,  it  appears  as 
if  there  was  but  one  toe  in  front  opposed  to  one 
behind. 


period  on  parental  care.  The  brain  arrives  in 
this  order  at  its  greatest  proportional  size ;  the 
organ  of  voice  here  attains  its  utmost  com- 
plexity, and  all  the  characteristics  of  the  bird, 
as  power  of  flight,  melody  of  voice,  and 
beauty  of  plumage  are  enjoyed  in  the  highest 
perfection  by  one  or  other  of  the  groups  of  this 
extensive  and  varied  order. 

The  beak  of  the  Insessores  varies  in  form 
according  to  the  nature  of  their  food,  which 
may  be  small  or  young  birds,  carrion,  insects, 
fruit,  seeds,  vegetable  juices,  or  of  a  mixed 
kind.  The  modifications  of  the  rostrum 
have  therefore  afforded  convenient  characters 
for  the  tribes  or  subdivisions  of  the  order ; 
these  are  termed,  1,  Dentirostres ;  2,  Coniros- 
tres;  3,  Tenuirostres ;  4,  Fissirostres. 

The  Dentirostres,  (jfifg»115) 
characterized  by  their  insect 
food,  and  the  notch  near  the 
extremity  of  the  upper  man- 
dible, include  the  families 
termed  Laniadte  or  Shrikes  ; 
Merulidtf,  Thrushes;  Sylvi-  Rostrum  of  a  Shrike 
ad(E,  Warblers;  Pipridt?,  Tits;  and  Muscica- 
pidte,  Fly-catchers. 

The  Conirostres  (Jig.  116)  include  the  two 

Fig.  116. 


Fig.  114. 


T  -^ 
Rostrum  of  a  Crow. 

orders  of  M.Temminck,  termed  Omnivores and 
Granivores ;  and  are  characterized  by  a  strong 
and  conical  beak,  the  margin  of  which  is  gene- 
rally entire;  the  greater  part  are  omnivorous, 
the  rest  granivorous;  these  latter  are  the  Hard- 
billed  Birds  of  Ray.  The  families  of  the  tribe 
are  the  following:  Sturnida,  Starlings;  Cor- 
vid<e,  Crows ;  Buccrid<e,  Hornbills  ; 
Cross-bills ;  Fringillidtf,  Finches,  Larks. 

The     Tenuirostres 

(fg.  1 1 7)  or  suctorial  Fig*  1 1 7. 

birds  form,  Mr. Vigors 
observes,  "  the  most 
interesting  group,  per- 
haps, of  the  animal  RostrumoftheOrthorhynchus, 
worl d .  Deriving  their  or  Straight-billed  Humming 
subsistence  for  the  most  Bird. 

part  from  the  nectar  of  flowers,*  we  never  fail  to 
associate  them  in  idea  with  that  more  beautiful 
and  perfect  part  of  the  vegetable  creation,  with 
which  in  their  delicacy  and  fragility  of  form, 
their  variety  and  brilliancy  of  hues,  not  less  than 
by  their  extracting  their  nourishment  from 
vegetable  juices,  they  appear  to  have  so  many 
relations.  As  the  tribe  is  confined  exclusively 
to  the  torrid  zone  and  southern  hemisphere, 
the  naturalists  of  our  northern  latitudes  have 
little  opportunity  of  observing  their  manners 
or  of  inspecting  their  internal  construction."  -f- 

*  In  the  Humming-Birds  which  we  have  dis- 
sected, we  have  found  the  remains  of  minute  insects 
in  the  gizzard. 

t  We  have  selected  the  skeleton  of  the  Humming, 
bird,  one  of  this  tribe,  as  a  striking  illustration  of  the 


268 


AVES. 


Fig.  118. 

****». 


Rostrum  of  the 
Capiimulgus. 


This  distinguished  ornithologist  proposes  to 
divide  the  Tenuirostres  into  the  following 
families :  Cinnyrida,  Sugar-eaters ;  Trochilida, 
Humming-birds; — in  which  families  the  beak 
and  feet  are  more  remarkable  for  their  tenuity 
and  length  :  and  Promeropidee,  Hoopoes ;  Me- 
liphagidfB,  Honey-suckers  ;  Nectariniada,  Nec- 
tar-birds ; — in  which  the  slenderness  of  the  beak 
and  feet  is  less  remarkable. 

The  Fissirostres,  (fig- 
118J,  like  the  Tenuirostres, 
are  distinguished  by  a  habit 
of  feeding  on  the  wing,  but 
as  their  food,  instead  of 
vegetable  juices,  consists  of 
living  insects,  the  form  of 
the  beak  is  modified  accordingly,  and  is  re- 
markable for  its  shortness  and  the  wideness 
of  its  gape,  especially  in  the  typical  families. 
In  these  the  mode  of  catching  the  prey  is  con- 
formable to  their  distinguishing  characters  ;  they 
receive  it  in  full  flight  into  the  cavity  of  their 
mouths,  which  remain  open  for  that  purpose,  and 
where  a  viscous  exudation  within  and  a  strong 
fence  ofvibriss<e  on  the  exterior,  assist  in  secur- 
ing the  victim.  The  longer-billed  Fissirostres, 
on  the  other  hand,  seize  their  food  by  their  bills. 
The  following  are  the  families  of  the  Fissirostral 
tribe :  Hirundinida:,  Swallows ;  Caprimulgida, 
Goat-suckers;  these  are  characterized  by  the 
short,  wide,  and  weak  bill.  Todid*,  Todies ; 
Halcyonidte,  King-fishers ; 
eaters :  these  latter  fa- 


milies are  characterized 
by  their  stronger  and 
longer  bill,  and  fur- 
ther differ  from  the 
preceding  in  having 
the  external  toe  nearly 
as  long  as  the  middle 
one  to  which  it  is 
united  as  far  as  the 
penultimate  j  oint ;  they 
are  therefore  termed 
Syndactyles  by  Cuvier. 
Fig.  119  represents  the 
foot  of  the  King-fisher. 


Meropida,   Bee- 
Fig.  119. 


Order  III.  SCANSORES. 


Feet  with  two 
toes  before  and  one 
behind.  ( Fig.  120.) 
The  disposition  of 
the  toes  which  re- 
sults from  the  ex- 
ternal one  being 
turned  back  like  the 
thumb,  gives  the 
Scansores  great  fa- 
cility in  climbing 
the  branches  of 
trees,  but  proporti- 
onally impedes  their 
progression  along 
level  ground.*  Their 


Fig.  120. 


Foot  of  the  Woodpecker. 


adaptation  of  the  vertebrate  skeleton  to  powers  of 
flight. 

*  There   are   peculiar   exceptions  to  the  general 
character  in  this  as  in  most  other  orders  of  birds. 


nests  are  less  skilfully  constructed  than  those 
of  the  Insessores,  and  are  generally  made  in 
the  hollows  of  old  trees ;  one  family,  indeed, 
is  remarkable  for  depositing  its  eggs  in  the 
nests  of  other  birds.  Their  powers  of  flight 
are  moderate  ;*  their  food  consists  of  insects 
and  fruit.  The  scansorial  families  are  the 
Psittacufa,  Parrots;  Picida,  Woodpeckers, 
Wry-necks ;  Cuculidae,  Cuckoos ;  Rhamphas- 
tid(£,  Toucans. 


Order  IV.  RASORES. 

Upper  mandible,  vaulted ;  nostrils,  pierced 
in  a  membranous  space  at  their  base,  covered 
by  a  cartilaginous  scale.  Legs,  strong,  mus- 
cular ;  three  toes  before  united  at  their  base  by 
a  short  membrane,  and  one  behind,  higher 
than  the  rest,  furnished  with  short,  blunt,  and 
robust  nails,  for  the  purpose  of  scratching  up 
the  food.  Tail-fea- 
thers 14—18. 

The  food  of  the 
Scratchers,  or  gal- 
linaceous birds,  be- 
ing vegetable  sub- 
stances, as  grains  and 
seeds,  they  have  a 
large  crop  and  ex- 
tremely muscular  „ 
gizzard.  They  most-  Beak  of  the  Outn^a-fowl. 

ly  deposit  and  hatch  their  eggs  on  the  ground 
in  a  rudely  constructed  nest  of  straw.  Each 
male  has  ordinarily  many  females,  he  takes  no 
part  in  nidification  or  in  rearing  the  young ; 
and  these  are  generally  numerous  and  able  to 
run  about  and  provide  for  themselves  the  mo- 
ment they  quit  the  shell. 

The  families  of  the  Rasores  are  the  Colum- 
bida,  or  Dove-tribe  ;  Cracidte,  Curassow-birds  ; 
Phasianidtz,  Pheasant,  common  Fowl ;  Tetra- 
onidtf,  Grouse,  Partridge. 


Fig.  121. 


Order  V.  CURSORES. 

Wings  very  short,  not  used  for  flying;  legs 
robust;  Sternum  without  a  keel. 

This  order  includes  the  Brevipennes,  which 
constitute  a  tribe  of  Waders  (Grallae)  in  the 
Cuvierian  system  ;  and  form  in  the  system  of 
Mr.  Vigors,  a  family  of  Rasores  under  the 
term  Struthionida.  They  differ  remarkably 
from  one  another,  both  in  the  form  of  the  beak 
and  feet,  and  each  known  species  forms  the 
type  of  either  a  separate  genus  or  family. 

Among  the  Cuculidae,  the  '  Traveller's  Friend/  of 
South  America,'  and  among  the  Psittacidee,  the 
•  ground  parrots '  of  New  South  Wales,  are  remark- 
able for  their  preference  of  the  ground,  for  progres- 
sion along  which  their  elongated  naked  tarsus,  and 
slender  toes,  of  which  one  of  the  hind  ones  can  be 
brought  forward  to  the  front  row,  favourably  adapt 
them. 

*  The  Trichoglossi  of  New  Holland  afford  as  re- 
markable an  exception  in  respect  of  powers  of  flight ; 
for  instead  of  the  usual  short  rounded  wings  of  the 
parrot  tribe,  they  have  them  elongated  and  pointed 
like  those  of  a  hawk,  and  dart  through  the  forests 
with  inconceivable  rapidity. 


AVES. 


26 


Fig.  122. 


The  Coursers  with 
a  depressed  beak  have 
the  longest  and  strong- 
est legs,  and  run  with 
remarkable  velocity ; 
these  include 

The  Ostrich  (Stru- 
t/no Camelus)  which 
has  only  two  toes. 
(Fig.  122.) 

TheltheafR^a  Ame- 
ricana.) 

The   Cassowary  (Cas- 
suarius  galeatvs.) 

The  Emeu  ( Dromaiiis  \ 
ater.)  ) 

Of  these  four  giants  of  the  class  the  first 
inhabits  the  continent  of  Africa,  the  second 
South  America,  the  third  Java,  and  the  fourth 
Australia. 

The  Coursers,  with  a  compressed  beak,  are 
represented  by  a  single  and  now  extinct  genus, 
the  Dodo,  ( Didus  ineptus,  Linn.) 

This  bird  is  known  from  a  description  given 
by  one  of  the  early  Dutch  navigators,  and 
preserved  in  Clusius  (Exoticorum  libri  de- 
cent descr.  1605,  pp.  99  and  100);  by  an  oil- 
painting  of  the  same  period,  copied  by  Ed- 
wards (Gleanings,  plate  294);  from  a  de- 
scription and  figure  in  Herbert's  Some  Years 
Travels  in  Africa,  Asia,  4~c.  1677;  and  from 
the  Historia  Naturalis  et  Medica,  of  Jacob 
Bontius,  1658.  N 

A  foot  of  the  Dodo  is  preserved  in  the  British 
Museum,  and  a  head  in  the  Ashmolean  col- 
lection at  Oxford.  The  beak  resembles  that  of 
the  Penguin  or  Albatross  rather  than  that  of 
a  Vulture,  to  which  it  has  been  compared. 
The  foot  would  resemble  that  of  the  Apteno- 
dytes,  if  it  were  webbed,  which  however  it  is 
not  nor  has  been.  It  is  very  similar  to,  but 
proportionally  stronger  than,  the  foot  of  the 
Curassow.  We  have  examined  carefully  the 
foot  in  the  British  Museum,  and  also  the  head 
of  the  Dodo  at  the  Ashmolean  Museum,  and 
derived  a  conviction  that  they  are  the  remains 
of  a  bird  sui  generis. 

A  third  form  of  beak  among  the  Brevipennes 
or  Cursores  is  presented  by  the  Apteryx  Aus- 
tralis ;  a  bird  inhabiting  and  apparently  pecu- 
liar to  the  island  of  New  Zealand.  The  man- 
dibles are  elongated  and  slender,  the  upper 
one  is  marked  on  either  side  by  a  longitudinal 
furrow.  The  toes  are,  as  in  the  Dodo,  four  in 
number ;  but  the  fourth,  or  posterior  one,  is 
smaller,  being  reduced  almost  to  a  spur,  and 
the  three  anterior  ones  have  the  lateral  skin, 
notched  as  in  the  Phaleropes.  The  wings  are 
shorter  than  in  any  other  known  bird,  are  quite 
concealed  by  the  feathers,  and  terminate  in  a 
sharp  spine  or  claw.  The  feathers  are  narrow 
like  those  of  the  Cassowary. 

OrdoVI.   GRALLATORES. 

Legs  with  the  tibia,  and  especially  the  me- 
tatarsus very  long,  stretched  out  behind  in 
flight;  the  distal  end  of  the  tibia  unfeathered; 
toes  elongated,  straight.  Wings  long.  Body 
slender;  neck  and  beak  long. 


Fig.  123. 


Head  and  leg  of  tJie  Ibis. 
The  Waders, — or  Gralla,  as  they  were  termed 
by  Linnaeus  from  being  raised  on  their  long 
legs,  as  on  stilts, — frequent  for  the  most  part 
the  banks  of  lakes  and  rivers,  marshes,  and 
the  shores  of  estuaries,  and  derive  their  food, 
some  exclusively  from  the  waters,  feeding  on 
small  fishes,  aquatic  mollusks,  worms,  small 
reptiles,  and  insects,  as  well  as  their  spawn, 
while  others  are  of  more  terrestrial  habits  and 
food.  Of  the  latter  kind  are  the  Gruid<e,  or 
Stork  tribe,  which  are  chiefly  vegetable  feeders, 
and  resemble  the  land  birds  in  their  bill  and 
feet;  the  former  being  more  obtuse  than  in 
the  typical  waders,  and  the  latter  shorter.  Then 
follow  the  Ardeidte,  or  Heron  tribe ;  the  Scolo- 
pacida;,  Snipe,  Woodcock ;  the  Rallidtf,  Rail, 
Coot;  and  the  Charadriada,  Plover,  Sander- 
ling,  &c. 

The  Waders  are  remarkable  for  their  power 
of  preserving  a  motionless  position  upon  one 
leg  for  a  considerable  length  of  time ;  the 
mechanism  by  which  this  is  effected  will  be 
afterwards  described.  During  flight  they 
stretch  out  their  long  legs  behind  to  counter- 
balance their  long  neck,  and  the  tail  is  always 
extremely  short,  its  function  as  a  rudder  being 
transferred  to  the  legs.  They  mostly  make  or 
choose  their  nests  on  the  ground,  and  the  young 
are  enabled  to  run  about  as  soon  as  hatched, 
excepting  in  those  Waders  which  live  in  pairs. 

OrdoVII.  NATATORES. 

Body  closely  covered  with  feathers,  and 
coated  with  a  thick  down  next  the  skin.  Legs 
short,  placed  behind  the  point  of  equilibrium. 
Toes  united  by  a  membrane  or  web,  which  is 
sometimes  divided. 

The  Swimmers,  or 
Palmipedes,  are  of  all 
the  orders  of  birds  the 
most  easily  recogniza- 
ble by  the  structure  and 
position  of  their  oar- 
like  feet:  this  peculi- 
arity which  occasions  an 
awkward  gait  on  land, 
is  extremely  favourable 
to  those  birds  '  whose 
business  is  in  the  great 
waters.'  Their  body 
is  boat-shaped,  and  ge- 
nerally elongated,  as  is 
Foot  of  the  Pelican. 


Fig.  124. 


270 


AVES. 


also  their  neck.  Their  dense  plumage  is  oiled 
and  lubricated  by  the  secretion  of  the  coccy- 
geal  glands,  which  are  remarkably  developed 
for  that  purpose.  In  general  the*  males  have 
many  females,  and  in  harmony  with  this  spe- 
ciality the  young  are  hatched  in  a  condition 
which  renders  the  cooperation  of  both  parents 
for  their  support  unnecessary,  being  able  to 
take  to  the  water  and  swim  about  in  search 
of  food  the  instant  that  they  are  liberated  from 
the  egg-coverings.  The  families  of  Swimmers 
are  the  Anatidte,  Swan,  Goose,  Duck;  Co- 
lymbida,  Divers ;  Alcad<e,  Auks ;  Pelecanidg, 
Pelican,  Cormorant,  Gannet ;  Larida,  Gulls. 

1.  Osteology. — The  skeleton  of  Birds  is  re- 
markable for  the  rapidity  of  its  development 
and  the  light  and  elegant  mechanism  displayed 
in  the  adaptation  of  its  several  parts.  The 
osseous  substance  is  compact,  and  exhibits 
more  of  the  laminated  and  less  of  the  fibrous 
texture  than  in  the  other  vertebrate  classes. 
This  is  more  especially  the  case  in  those  parts 
of  the  skeleton  which  are  permeated  by  the  air. 
The  bones  which  present  this  singular  modifi- 
cation have  a  greater  proportion  of  the  phosphate 
of  lime  in  their  composition  than  is  found  in 
the  osseous  system  of  the  mammalia,  and  they 
are  whiter  than  the  bones  of  any  other  animal. 
In  the  bones  where  the  medulla  is  not  dis- 
placed or  dessicated  by  the  extension  of  the 
air-cells  into  their  interior,  the  colour  is  of  a 
duller  white.  In  the  Silk  or  Negro-fowl  of 
the  Cape  de  Verd  Islands  (Gallus  Morio, 
Temminck)  the  periosteal  covering  of  the 
bones  is  of  a  dark  brown,  and  in  some  parts 
almost  black  colour ;  but  this  ought  to  be  re- 
garded as  a  peculiarity  of  the  cellular  rather 
than  of  the  osseous  texture,  which  does  not 
differ  in  colour  from  that  of  other  birds ; 
indeed  the  thin  aponeurosis  covering  the  lateral 
tendons  of  the  gizzard  of  the  Silk-fowl  is 
observed  to  have  the  same  dark  hue  as  the 
membrane  which  invests  the  bones. 

Although  in  the  disposition  of  the  parts  of 
the  osseous  system  of  birds  the  plan  which 
pervades  the  vertebrate  type  of  structure  is 
nowhere  absolutely  violated,  yet  the  variations 
from  that  plan  required  by  the  peculiar  exigen- 
cies of  the  class  are  of  the  most  striking  and 
interesting  kind.  We  shall  successively  con- 
sider the  relations  of  these  modifications  to 
the  powers  and  habits  of  the  bird  as  they 
present  themselves  in  the  vertebral  axis,  in  the 
bones  of  the  head  and  thorax,  and  in  those 
of  the  anterior  and  posterior  extremities. 

Fig.  125. 


Skeleton  of  the  Topats  Humming  Bird  (  Trochilus  Pella 


The  vertebral  axis  or  spine  is  divisible  into  a 
cervical  (Jig- 125,  a),  dorsal  (b),  sacral  (c),  and 
caudal  ((/)  region ;  the  vertebrae  immediately 
succeeding  those  which  bear  ribs  have  a  lateral 
anchylosis  with  the  iliac  bones,  and  therefore 
there  is  no  part  of  the  spine  which  possesses 
the  characters  of  the  lumbar  vertebrae  of  mam- 
malia and  reptiles. 

The  vertebrae  are  the  first  parts  of  the  osseous 
system  which  make  their  appearance  in  the 
development  of  the  embryo,  and  they  are  of 
all  parts  of  the  skeleton  the  most  constant  in 
their  existence  and  general  characters. 

The  dorsal  or  costal  vertebras  in  birds  rarely 
form  more  than  a  fourth  part  of  the  entire 
vertebral  column,  and  in  some  of  the  long- 
necked  Grallatores,  as  the  Stork,  form  only 
an  eighth  part  of  the  spine ;  they  have  not 
been  observed  to  be  fewer  than  six  nor  more 
than  eleven  in  number  throughout  the  class : 
the  latter  obtains  in  the  Swans  (  Cygnm  canorus 
et  olor)  and  Sheldrake;  the  most  common 
numbers  are  seven  or  eight. 

The  dorsal  vertebra  are  short,  as  compared 
with  the  cervical :  they  appear  broad  when 
viewed  superiorly,  in  consequence  of  the  great 
development  of  the  transverse  processes ;  but 
their  bodies  are  much  compressed  in  the  lateral 
direction,  so  as  to  be  reduced  almost  to  the 
form  of  vertical  laminae  towards  the  sacral 
region.  This  is  especially  observable  in  the 
Penguins  ( Aptenodytes,  Catarrhactes) ;  but 
in  the  Ostrich  the  bodies  of  the  dorsal  ver- 
tebrae retain  their  breadth  throughout. 

The  bodies  are  not  united  by  intervertebral 
substances,  but  by  capsular  ligaments  and 
synovial  membranes ;  the  anterior  articular 
cartilaginous  surface  is  convex  in  the  vertical 
direction,  and  concave  in  the  transverse ;  the 
posterior  surface  is  the  reverse.  The  Penguins, 
however,  present  a  remarkable  exception  to 
this  rule.  The  posterior  surface  of  the  third 
dorsal  vertebra  is  uniformly  concave,  to  which 
the  opposed  end  of  the  fourth  vertebra  presents 
a  corresponding  convexity  :  the  ball  and  socket 
joint  is  continued  between  the  several  ver- 
tebrae to  the  last  dorsal,  which  is  anchy- 
losed  to  the  sacrum.  This  is  an  interesting 
affinity  to  the  Reptilia,  in  addition  to  numerous 
others  displayed  in  the  construction  of  these 
singular  birds.  In  most  birds  the  bodies  of 
some  of  the  middle  dorsal  vertebrae  are  an- 
chylosed  together ;  and  in  general  those  which 
are  nearest  the  sacrum.  In  the  Flamingo  we 
have  observed  this  anchylosis  extending  from 
the  second  to  the  fifth 
dorsal  vertebra.  In  the 
Sparrow-hawk  the  second, 
third,  fourth,  and  fifth 
dorsal  vertebrae  are  conso- 
lidated into  one  piece, 
while  the  sixth  enjoys  con- 
siderable lateral  motion 
both  upon  the  fifth  and 
seventh,  which  last  is  an- 
chylosed  to  the  sacrum  ; 
so  that  the  body  can  be 
rapidly  and  extensively  in- 
flected towards  either  side 


AVES. 


271 


during  the  pursuit  of  prey.  This  structure 
and  its  uses  were  first  pointed  out  by  Mr. 
H.Earle. 

The  bodies  of  the  anterior  dorsal  vertebra 
send  down  processes  from  their  inferior  or 
ventral  surfaces  for  the  advantageous  origin 
of  the  recti  antici  majores  muscles  of  the  neck. 
These  processes  differ  from  the  inferior  spines 
of  the  tail  in  not  being  perforated  for  the 
passage  of  an  artery.  This  part  of  the  spine 
is  further  strengthened  by  the  extension  of 
osseous  splints  from  the  transverse  processes, 
which  unite  those  of  contiguous  vertebrae  to- 
gether, and  also  by  the  anchylosis  of  the 
spinous  processes.  But  where  a  similar  ne- 
cessity for  the  fixation  of  the  trunk  does  not 
exist,  as  in  the  Struthious  birds  and  Penguins, 
which  cannot  fly,  all  the  dorsal  vertebrae  are 
moveable  upon  each  other.  When  it  is  con- 
sidered that  the  head,  posterior  extremities, 
and  viscera  are  suspended  in  flight  from  this 
central  portion  of  the  trunk,  and  that  it  has 
almost  exclusively  to  sustain  the  shock  of  the 
violent  contractions  of  the  principal  muscles 
of  the  wings,  the  necessity  for  the  mechanism 
consolidating  the  dorsal  vertebrae  will  be  readily 
appreciated. 

Immobility  and  strength  are  still  more  ob- 
viously required  in  that  part  of  the  spine  by 
which  the  weight  of  a  horizontal  body  is  to 
be  transferred  to  a  single  pair  of  extremities 
articulated  to  the  trunk  behind  the  centre 
of  gravity.  The  anchylosis  of  the  bodies  of 
the  vertebrae,  which  already  begins  to  appear 
in  the  last  dorsal,  is,  therefore,  continued 
through  all  the  sacral  vertebrae  as  far  as  the 
caudal  region;  and  this  consolidated  mass 
(b  to  c)  is  united  laterally  to  the  iliac  bones. 
Hence  it  is  always  difficult  to  determine  the 
number  of  vertebrae  of  which  it  is  composed. 
We  have  made  sections  of  the  sacrums  of  many 
different  birds  with  a  view  to  determine  this 
fact,  and  have  generally  found  the  number 
greater  than  that  which  is  indicated  in  the 
tables  of  Cuvier.  Thus  the  Stork  has  twelve, 
instead  of  eleven  sacral  vertebrae ;  the  Coot 
thirteen,  instead  of  seven ;  the  Kingfisher 
eleven,  instead  of  eight:  while  the  Ostrich,  on 
the  other  hand,  has  but  seventeen,  instead  of 
twenty  bones  of  the  sacrum.  The  bodies  of 
the  sacral  vertebrae  are  broad,  but  shallow,  and 
towards  the  tail  the  floor  of  the  vertebral  canal 
is  formed  by  a  mere  lamina  of  bone  :  the  canal 
is  remarkably  dilated  in  this  part  of  the  spine 
for  the  enlargement  of  the  cord  which  gives 
off  the  nerves  to  the  posterior  extremity.  It 
is  a  curious  fact  that  the  roots  of  these  nerves 
pass  out  of  the  osseous  canal  by  separate 
orifices,  the  ganglion  on  the  posterior  root 
and  the  union  of  the  two  being  external  to  the 
spine.  The  aspect  of  all  these  orifices  is  la- 
teral, in  the  intervals  of  the  transverse  pro- 
cesses of  the  different  vertebras,  which  are  not 
united  together  as  in  the  mammalia.  The  first 
four  or  five  sacral  vertebrae  give  off  two  sets 
of  transverse  processes,  one  ventral,  the  other 
dorsal ;  the  ventral  ones  are  wanting  in  the 
succeeding  four,  and  then  suddenly  reappear 
to  abut  against  the  symphysis  of  the  ilium  and 


ischium,  and  are  so  continued  double  to  the 
end.  The  spinous  processes  which  are  prin- 
cipally developed  from  the  anterior  sacral  ver- 
tebrae, give  off  from  their  extremities  lateral 
expansions,  which  anchylose  with  the  iliac 
bones,  and  form  an  osseous  roof,  arching  over 
and  concealing  the  transverse  processes. 

The  coccygeal  vertebrae  of  birds,  though  never 
prolonged  into  a  conspicuous  caudal  appen- 
dage, are  in  general  moveable  upon  each  other, 
and  are  frequently  nine  in  number.  With  the 
exception  of  the  last,  they  are.broad  and  short 
and  perforated  for  the  lodgement  of  the  spinal 
marrow.  With  the  exception  of  the  last  also 
they  have  spines  on  both  the  dorsal  and  ventral 
aspects ;  and  the  anterior  vertebrae  have  also 
transverse  processes.  The  last  caudal  vertebra 
(d,  jig.  125)  is  so  singularly  shaped,  that  were 
it  found  alone  in  a  fossil  state  it  would  hardly 
be  recognized  as  a  bone  of  the  spine.  It  has 
no  medullary  canal  and  no  processes  ;  but  is 
compressed  laterally  and  terminates  above  and 
often  also  below  in  a  sharp  edge  ;  its  posterior 
extremity  is  obtuse.  It  supports  the  coccygeal 
oil-gland,  and  affords  a  firm  basis  to  the  tail 
feathers,  which,  from  their  use  in  guiding  the 
motions  of  the  bird  through  the  air,  Linnaeus 
termed  the  rectrices* 

In  the  Toucan  the  three  last  caudal  vertebrae 
are  anchylosed  together ;  the  six  anterior  ones 
are  articulated  by  ball  and  socket  joints,  the 
ball  and  the  socket  being  most  distinct  in 
the  two  last  of  these  joints ;  that  between  the 
sixth  and  seventh  vertebrae  is  provided  with  a 
capsule  and  synovial  fluid,  the  others  have 
a  yielding  ligamentous  mode  of  connexion. 
The  spinous  processes  of  these  vertebrae,  both 
superior  and  inferior,  are  of  moderate  size,  but 
smallest  in  the  sixth,  where  the  greatest  degree 
of  motion  takes  place ;  the  transverse  pro- 
cesses on  the  contrary  are  large  and  broad 
so  as  almost  to  preclude  lateral  motion.  We 
have  given  a  more  particular  description  of 
these  vertebrae  because  of  the  singular  move- 
ments observable  in  the  tail  of  the  Toucan ; 
it  can  be  inflected  dorsad  till  the  superior 
spines  of  the  vertebra  are  brought  in  contact 
with  the  sacrum ;  and  in  the  performance  of 
this  motion  the  lateral  muscles,  which  at  first 
tend  rather  to  oppose  the  elevators,  become,  at 
a  certain  point  of  inflection  dorsad  of  the  centre 
of  motion,  elevators  themselves,  and  thus  com- 
bining with  the  elevators  jerk  the  tail  upon  the 
back ;  it  is  thus  that  the  tail  turns  as  if  on  a 
hinge  operated  upon  by  a  spring. 

As  the  prehensile  functions  of  the  hand  are 
transferred  to  the  beak,  so  those  of  the  arm 
are  performed  by  the  neck  of  the  bird ;  this 
portion  of  the  spine  is  therefore  composed  of 
numerous,  elongated,  and  freely  moveable  ver- 
tebrae, and  is  never  so  short  or  so  rigid  but  that 
it  can  be  made  to  apply  the  beak  to  the  coccy- 
geal oil-gland,  and  to  every  part  of  the  body 
for  the  purpose  of  oiling  and  cleansing  the 
plumage.  In  birds  that  seek  their  food  in 

*  In  the  tail-less  variety  of  the  common  Fowl 
the  coccygeal  vertebrae  have  degenerated  into  a 
single  unshapely  knotty  process. 


272 


AVES. 


water  it  is  in  general  remarkably  elongated, 
whether  they  support  themselves  on  the  surface 
by  means  of  short  and  strong  natatory  feet,  as 
in  the  Swan,  or  wade  into  rivers  and  marshes 
on  elevated  stilts,  as  in  the  Crane,  &c. 

The  articular  surfaces  of  the  bodies  of  the 
cervical  vertebrae,  like  those  of  the -dorsal  series 
above  mentioned,  are  concave  in  one  direction 
and  convex  in  the  other,  so  as  to  lock  into  each 
other,  and  in  such  a  manner  that  the  superior 
vertebra  move  more  freely  forwards,  the  middle 
ones  backwards,  while  the  inferior  ones  again 
bend  forwards ;  producing  the  ordinary  sigmoid 
curve  observable  in  the  neck  of  the  bird. 

This  mechanism  is  most  readily  seen  in  the 
long-necked  waders  which  live  on  fish  and 
seize  their  prey  by  darting  the  bill  with  sudden 
velocity  into  the  water.  In  the  common  Heron, 
for  example,  (Ardea  cinerea)  the  head  can  be 
bent  forward  on  the  atlas  or  first  vertebra,  the 
first  upon  the  second  in  the  same  direction, 
and  so  on  to  the  sixth,  between  which  and 
the  fifth  the  forward  inflection  is  the  greatest ; 
while  in  the  opposite  direction  these  vertebrae 
can  only  be  brought  into  a  straight  line.  From 
the  sixth  cervical  vertebra  to  the  thirteenth  the 
neck  can  only  be  bent  backwards ;  while  in 
the  opposite  direction  it  is  also  arrested  at  a 
straight  line.  From  the  fourteenth  to  the 
eighteenth  the  articular  surfaces  again  allow 
of  the  forward  inflection,  but  also  limit  the 
opposite  motion  to  the  straight  line. 

Two  transverse  processes  are  ordinarily  con- 
tinued from  the  anterior  part  of  the  bodies  of 
the  cervical  vertebrae  :  the  inter-space  of  these 
is  filled  up  externally  to  the  vertebral  artery 
by  a  rudimentary  styliform  rib,  which  is  sepa- 
rated in  the  young  bird,  but  afterwards  ancliy- 
losed,  and  directed  backwards  parallel  to  the 
body  of  the  vertebrae.  These  processes  give 
attachment  to  numerous  muscles  of  the  neck, 
and  being,  with  the  transverse  processes,  more 
strongly  developed  in  the  rapacious  birds,  give 
a  greater  breadth  to  the  cervical  region  in  that 
order. 

The  superior  spinous  processes  are  but 
feebly  developed  ;  they  are  most  distinct  on 
the  vertebrae  at  the  two  extremities  of  the 
cervical  portion  of  the  spine.  Inferior  spinous 
processes  are  also  found  on  the  vertebrae  at 
the  commencement  and  termination  of  the 
neck,  but  are  wanting  in  a  great  proportion  of 
the  intermediate  cervical  vertebrae. 

The  atlas  is  a  simple  ring.  In  general  it 
is  articulated  with  the  occipital  tubercle  by 
a  single  concave  facet  on  the  body ;  but  in 
the  Penguin  and  Ostrich  there  are  two  other 
facets,  continuous  with  the  middle  one,  but 
corresponding  with  the  anterior  articulating  pro- 
cesses of  the  rest  of  the  vertebrae  and  applied  to 
the  condyloid  portions  of  the  occipital  bone, 
while  the  middle  facet  is  articulated  to  the  ba- 
silar  portion  as  in  other  birds.  The  body  of 
the  dentata  is  joined  to  the  atlas  by  a  single 
synovial  capsule,  its  odontoid  process  is  tied 
down  by  a  strong  transverse  ligament  stretched 
above  it,  and  by  a  longitudinal  one  extending 
from  its  extremity  to  the  posterior  part  of  the 
occipital  condyle.  In  the  articulations  of  the 


bodies  of  the  remaining  cervical  vertebrae  a 
moveable  inter-articular  cartilage  is  found  in- 
closed between  reduplications  of  the  synovial 
membrane,  as  in  the  joint  of  the  lower  jaw  in 
mammalia.  The  articulations  of  the  oblique 
processes  have  no  peculiarities  worthy  of  no- 
tice. 

A  remarkable  difference  is  found  in  the 
diameter  of  the  spinal  canal  contained  in  the 
cervical  vertebrae.  If,  e.  g.  the  sixth  cervical 
vertebra  of  a  Stork  be  sawed  down  verti- 
cally, the  antero-posterior  diameter  is  greatest 
in  the  middle,  least  at  the  ends ;  but  if  it  be 
sawed  lengthwise  horizontally,  the  transverse 
diameter  is  the  reverse,  being  narrowest  at 
the  centre  and  widest  at  the  ends.  In  the 
Ostrich,  the  Swan,  and  many  other  birds  the 
spinal  canal  is  widened  in  every  direction  at 
the  extremities  of  the  vertebrae ;  and  on  the  dor- 
sal or  posterior  aspect  of  the  spine,  the  canal 
remains  open  for  some  extent  in  the  intervals  of 
the  vertebrae,  the  cord  being  there  protected 
only  by  membrane  and  the  elastic  ligaments 
which  connect  the  roots  of  the  spinous  pro- 
cesses together.  The  final  purpose  of  this 
structure  has  been  ably  illustrated  by  Mr.  Earle 
in  the  Philosophical  Transactions,  (1822,  p. 
276.)  where  he  shews  that  it  is  adapted  to  pre- 
vent a  compression  of  the  spinal  cord  during 
the  varied  and  extensive  inflections  of  the  neck. 

The  vertebrae  of  the  different  regions  of  the 
spine  bear  a  different  proportion  to  each  other 
in  respect  to  number  among  birds,  from  what 
we  observe  in  the  mammalia  and  reptilia.  The 
cervical  portion  in  this  class  is  generally  com- 
posed of  a  much  greater  number  of  vertebrae 
than  any  of  the  other  divisions  of  the  spine ; 
in  this  respect  the  fossil  reptilian  genus  called 
Plesiosaurus  alone  resembles  the  bird.  This 
singular  animal  was  an  inhabitant  of  the 
waters,  and  it  is  interesting  to  observe  that 
the  peculiarity  which  distinguishes  it,  viz.  the 
great  length  of  neck,  is  chiefly  characteristic 
of  the  Aves  aquatics  of  Nitzsch.  In  the  Gral- 
latores  the  length  of  the  neck  is  determined  by 
the  height  of  the  legs  :  in  the  Natatores  it  is 
necessary  for  the  purpose  of  obtaining  their 
food  while  swimming  the  waters.  The  dorsal 
vertebrae  are  usually  less  numerous  than  in 
mammalia.  The  caudal  vertebrae  are  subject 
to  few  variations;  they  never  project  in  the 
form  of  a  tail,  but  are  most  numerous  in  those 
birds  which  make  the  greatest  use  of  the  tail- 
feathers,  as  in  the  Swallows,  to  direct  their 
rapid  flight,  and  in  the  Woodpeckers,  where 
they  serve  as  a  prop  or  climbing  pole. 

The  following  table,  which,  with  some  cor- 
rections, is  extracted  from  Cuvier's  Lefons 
d'Anatomie  Comparee,  exhibits  the  variety 
that  exists  with  respect  to  the  number  of  ver- 
tebrae in  different  species  of  birds. 

Table  of  the  number  of  vertebra  in  birds. 

Order.   RAPTORES  Vertebra. 

Species.  Cervical.  Dorsal.   Sacral.  Caudal. 

Vulture 13  7  11  7 

Eagle 13  8  11  8 

Osprey    14  8  11 

Sparrow-hawk..  11  8  11  8 


AVES. 


273 


Species. 


Buzzard 11  7 

Kite 12  8 

Great     Horned 

Owl 13  7 

Hawk-owl 11  8 

Order.     INSESSORES. 

Flycatcher  ....  10  8 

lihick-bird 11  8 

Tanager 10  8 

Crow 13  8 

Maupie 13  8 

Ja/ 12  7 

Starling 10  8 

Gross-beak 10  7 

Bull-finch  ....  10  6 

Sparrow 9  9 

Goldfinch 11  8 

Titmouse    ....  11  8 

Lark    11  9 

Redbreast  ....  W^  8 

Swallow 1.1  ^  8 

Night-jar     ....  11  8 

Humming-bird  14  9 

Hoopoe  ......  12  7 

King-fisher  ....  12  7 

Order.     SCANSORES. 

Woodpecker  ..12  8 

Toucan    (Ariel)  12  8 

Parrot 11  9 

Order.     RASORES. 

Pigeon    13  7 

Peacock 14  7 

Pheasant 13  7 

Turkey    15  7 

Crested    Curas- 

sow 15  8 

Order.     CURSORES. 

Ostrich   18  10 

Cassowary ....  16  10 

Rhea 14  9 

Emeu 19  9 

Order.     GRALLATORES. 

Heron 18  7 

Stork 19  7 

Crane 19  9 

Argala 14  7 

Spoon-bill 17  7 

Avoset 14  9 

Plover 15  8 

Lapwing 14  8 

Wood-cock 18  7 

Curlew 13  8 

Oyster-catcher..  12  9 

Rail  13  8 

Coot 15  10 

Jacana    14  8 

Flamingo   ....  18  7 


Cervical.  Dorsal.   Sacral.  Caudal. 


10 
11 

12 
11 


10 

10 

9 

13 
13 
11 
10 
12 
11 
10 
11 
11 
10 
10 

11 
11 

10 

8 

11 


10 
12 
11 


13 
12 
15 

10 

10 


10 
12 
12 
13 
14 
10 
10 
10 
13 
10 
15 
13 
13 
13 
12 


8 
9 
7 
6 
7 
8 
7 
7 
8 
9 
8 
8 
7 
7 

9 

9* 

8 

7 
8 
5 
5 


17  9 

19  7 

?t 

19  9 


*  Cuvier  says  "plus  de  7  :  "  we  have  ascertained 
the  above  number  in  a  dissection  of  a  recent  spe- 
cimen of  this  singular  genus  ( Rhamphastos  Ariel, 
Vigors)  Zool.  Proceedings,  vol.  11.  p.  42. 

t  This  part  of  the  spine  is  singularly  modified 
and  interrupted  by  a   natural   atrophy  of  many   of 
the  vertebrae. 
VOL.  I. 


7 

14 

7 

9 

14 

8 

8 

10 

8 

8 

11 

8 

9 

13 

9 

9 

13 

8 

11 

14 

8 

10 

14 

7 

10 

14 

9 

8 

15 

8 

11 

11 

9 

9 

14 

7 

8 

13 

7 

10 

13 

7 

Spicics.  Cervical.  Dorsal.  Sacral.  Caudal 

Order.     NATATORES. 

Pelican 16 

Cormorant  ....  16 

Tern   14 

Gull 12 

Petrel 14 

Catarrhactes   . .  13 

Swan 23 

Goose 15 

Barnacle   18 

Duck 14 

Sheldrake 16 

Scoter 15 

Merganser  ....  15 

Grebe 14 

The  skull  in  all  the  Vertebrated  Classes  is 
composed  of  a  considerable  number  of  osseous 
pieces,  which,  in  the  Mammalia,  unite  in  defi- 
nite numbers  and  proportions,  so  as  to  form 
the  bones  termed  occipital,  temporal,  sphenoidal, 
&c.  In  the  cold-blooded  Vertebrati  the  com- 
ponent parts  of  these  bones  generally  remain 
separated  throughout  life,  giving  an  appear- 
ance of  great  complexity  to  the  skull,  and  occa- 
sioning much  difficulty  in  tracing  their  cor- 
respondence with  the  cranial  bones  of  the 
higher  classes.  Equal  difficulty  is  experi- 
enced in  determining  the  component  parts  of 
the  head  in  Birds,  but  from  a  very  different 
cause.  In  the  cold-blooded  Crocodile,  and 
Fish,  this  difficulty  is  caused  by  the  tardiness 
of  ossification,  which  prevents  the  coalition  of 
the  several  elements  of  the  cranial  bones  into 
their  determinate  groups ;  while,  in  Birds,  the 

Fig.  126. 


Skull  nf,i  ijcnmq 


274 


AVES. 


energetic  respiratory  and  circulating  functions 
occasion  so  rapid  an  evolution  of  the  osseous 
system,  that  the  bones  of  the  cranium  become 
at  an  early  period  anchylosed  into  one  piece, 
with  a  total  obliteration  of  the  original  har- 
monise; it  is  necessary,  therefore,  to  examine 
the  skull  of  the  Bird  at  an  early  period  of  ex- 
istence, and  to  compare  it  with  the  foetal  con- 
dition of  the  skull  of  the  Mammal,  when  it  will 
be  found  to  be  ossified  from  analogous  centres, 
which,  in  their  expansion  and  subsequent 
union,  obey  the  same  laws  of,  as  it  were, 
elective  attraction. 

The  occipital  bone  is  originally  composed 
of  four  pieces:  the  basilar,  below,  ( a, fig.  126,) 
the  two  condyloid,  laterally,  ( 6,  b,)  and  the 
expanded  spinous  process,  or  supra-occipital 
piece  above  (c).  These  fulfil  the  usual 
functions  of  the  occipital  bone,  protecting  the 
cerebellum  and  medulla  oblongata,  and  form- 
ing the  medium  of  connection  between  the 
cranial  and  cervical  vertebrse. 

The  head  is  articulated  to  the  spine  by 
means  of  a  single  hemispherical  tubercle  (x9 
fig.  126,)  which  plays  in  a  corresponding 
cavity  of  the  atlas.  In  most  birds  the  tubercle 
is  formed  exclusively  by  the  basilar  piece  of 
the  occipital  bone,  but  in  the  Ostrich  and 
Penguin  the  condyloid  portions  also  contribute 
to  its  formation,  which  is  an  approximation  to 
the  structure  of  the  occipital  condyle  in  the 
Chelonian  reptiles.  In  all  birds,  however,  the 
articulation  is  such  as  to  allow  of  a  much  greater 
extent  and  freedom  of  motion  to  the  head  than 
exists  in  the  Mammalia. 

The  temporal  bone  consists  of  the  petrous  por- 
tion, the  squamous  portion,  (d,  d,fig.  126, 127) 
and  the  tympanic  bone,  or  os  quadratum  (e.) 
The  petrous  bone  includes  the  complex  parts 
of  the  internal  ear,  and  is  soon  anchylosed  to 
the  condyloid  portions  of  the  occipital  bone, 
which  fulfil  the  functions  of  the  mastoid  pro- 
cesses. The  squamous,  or,  as  it  may  be  termed, 
the  zygomatic  portion  of  the  temporal  bone  (d) 
remains  for  a  longer  time  separate;  it  forms 
the  lateral  boundary  of  the  cranial  cavity,  as  in 
quadrupeds,  and  the  tympanic  element  is  move- 
ably  articulated  to  its  inferior  part. 

The  parietal  bones  (f,f,  fig.  127)  retain 
their  separated  condition  till  after  the  union  of 
the  occipital  pieces,  they  then  unite  and  protect 
the  posterior  part  of  the  cerebral  hemispheres. 

The  sphenoid  bone  is  composed  of  a  basilar 
portion,  (g,fig.  1 26,)  two  orbital  plates,  (h,fig. 
127,)  forming  the  floor  and  part  of  the  septum 
of  the  orbits,  and  which  rapidly  anchylose  with 
the  preceding;  two  cranial  portions,  or  alse  ma- 
jores,  (g,  fig.  127,  128,)  which  remain  longer 
separate,,  and  form  the  posterior  part  of  the  or- 
bits, and  two  pterygoid  portions  (« interarticular ' 
or  'omoid'  bones),  (i,  i,  fig.  126,)  which,  in 
birds,  abut  against  the  tympanic  or  quadrate 
bones.  The  great  alee  of  the  sphenoid  join  the 
parietal,  and  separate  the  temporal  from  the 
frontal  bones. 

The  frontal  bone  (k,  fig.  127)  continues  for 
a  longer  period  than  the  parietal  to  be  sepa- 
rated into  two  lateral  halves  by  the  continuation 
of  the  sagittal  suture  through  its  whole  length. 


Fig.  127. 


The  ant-orbital 
processes  fl3, 
fig.    127)    are 
elongated   and 
pointed,       ex- 
tending      for- 
wards to  join 
the    lachrymal 
bones,     fo,  o, 
fig.  127,)  con- 
siderably    be- 
yond  the   ori- 
gins of  the  nasal 
bones,  and  are 
separated  from 
each   other  by 
these  and  by  a 
process  of  the 
ethmoid  bone. 
The  post-orbi- 
tal     processes 
are    most    de- 
veloped in  the 
Parrots       and 
Maccaws,      in 
the    latter    of 
whichtheyjoin 

Skull  of  a  young  Ostrich.  the    lachrymal 

bones,  and  complete  the  bony  circumference 
of  the  orbits,  (fig.  128.)  In  the  Emeu  they 
remain  for  a  long  time  distinct  bones,  as  in  the 
reptiles.  The  frontal  bone  thus  forms  the 
whole  of  the  superior,  and,  more  or  less,  of  the 
outer  boundary  of  the  orbits,  and  protects  the 
anterior  part  of  the  cerebrum.  It  supports 
the  horn-like  prominences  which  are  seen  upon 
the  heads  of  the  Cassowary,  Pintado,  and  Cu- 
rassow,  the  bony  bases  of  which  commence  by 
distinct  ossifications.* 

A  small  part  of  the  ethmoidal  bone  ( /, 
fig.  127)  is  seen,  in  the  Ostrich,  on  the  ex- 
terior of  the  cranium  lodged  between  the 
ant-orbital  processes  and  nasal  bones  (n,  n.) 
The  ethmoid  separates,  as  usual,  the  orbits  from 
the  cavity  of  the  nose,  and  forms  a  great  part  of 
the  inter-orbital  septum  where  this  exists,  as 
in  the  parrots,  (m,  fig.  128.) 

In  the  mature  bird  the  whole  of  the  prece- 
ding bones,  with  the  exception  of  the  tym- 
panic elements  of  the  temporal  bone,  are 
usually  found  anchylosed  into  one  piece. 

The  internal  surface  of  the  cranium  exhibits 
a  well-marked  transverse  ridge,  which  divides 
the  cavity  into  two  principal  depressions. 
In  the  anterior  division  the  hemispheres  of 

*  «  A  most  remarkable  sexual  difference  appears 
in  the  skull  of  the  crested  Hens:  in  these  the  frontal 
portion  of  the  cranium  is  dilated  into  an  immense 
cavity,  on  which  the  crest  of  feathers  is  placed. 
This  degeneracy  "of  the  formative  impulse,  which 
is  propagated  to  the  offspring,  is  quite  unparalleled 
in  the  whole  animal  kingdom  :  I  have  lately  ex- 
amined several  heads  of  such  hens  in  a  fresh  state, 
and  have  found  that  this  peculiar  dilatation  of  the 
cranium  is  filled  by  the  hemispheres  of  the  cere- 
brum, and  is  separated  from  the  posterior  part 
which  holds  the  cerebellum,  as  in  the  common 
hen,  by  an  intermediate  contracted  portion.  — Law- 
rence's Blumenbach's  Comp.  Anat.  p.  61. 


AVES. 


275 


the  cerebrum  are  lodged,  the  rest  of  the  brain 
is  contained  in  the  posterior  division.  The 
relative  proportion  of  these  divisions  varies  in 
the  different  orders;  in  the  Insessore.s  and  Ac- 
cipitrcs  the  anterior  superior  depression  is  the 
largest;  in  the  Rasores,  the  posterior  inferior 
depression  equals,  and  in  some  species,  ex- 
ceeds the  former  in  size.  The  orbits  form  two 
slight  projections  in  the  anterior  fossa  of  the 
cranium,  which  is  partially  divided  longitu- 
dinally by  a  ridge  corresponding  to  the  inter- 
space of  the  cerebral  hemispheres.  This  is 
developed  in  the  Gallinaceous  birds  into  a 
thin  falciform  osseous  crest,  which  is  especi- 
ally remarkable  in  the  Partridge,  Turkey,  and 
Capercailzie.  It  is  also  well  developed  in  the 
Parrot  tribe.  The  sella  turcica  in  all  birds  is 
a  deep  round  cell,  lodging  the  pituitary  gland, 
as  in  the  Mammalia. 

The  foramen  magnum  (l,Jig- 126)  is  formed, 
as  usual,  by  the  union  of  the  four  pieces  of  the 
occipital  bone  :  its  size  is  considerable,  having 
relation  to  the  mobility  of  the  cranium  upon 
the  spine.  The  foramen  lacerum  posterius 
(2,  2,  Jig.  126)  is  situated  immediately  below 
the  membrana  tympani  (8,  8,^.126.)  There 
is  no  fissure  analogous  to  the  foramen  lacerum 
medius.  The  carotid  foramina  (3,  3,  fig.  126) 
are  transversely  oblong,  and  situated  on  the 
body  of  the  sphenoid ;  the  same  bone,  in  the 
Ostrich,  is  perforated  immediately  anterior  to 
the  carotid  canal  by  the  Eustachian  tube,  (4,  4.) 
The  posterior  palatine  foramina  are  wide  spaces, 
(5,  5,)  separated  from  each  other  by  the  vomer 
(q,  Jig.  126).  Anterior  to  these,  in  the  base 
of  the  skull,  are  seen  the  still  wider  posterior 
apertures  of  the  nostrils  (6,  6).  In  the  inside 
of  the  cranium  the  internal  auditory  foramina 
are  distinctly  seen.  The  foramen  lacerum  an- 
terius  is  divided  into  several  distinct  foramina. 
The  optic  foramina,  on  the  contrary,  are  closely 
approximated,  and  frequently  blended  into  one. 
The  olfactory  nerves  escape  each  by  a  single 
foramen,  and  are  continued  to  the  nose  either 
along  a  deep  groove  on  the  upper  part  of  the 
orbital  septum,  or,  as  in  the  Toucan,  pass 
through  a  complete  osseous  canal. 

The  bones  of  the  face  correspond  in  number 
and  relative  position  with  those  of  the  Mam- 
malia, but  differ  considerably  in  their  forms 
and  proportions ;  they  bear  most  resemblance 
to  the  facial  bones  of  the  Rodentia.  They  are 
always  moveably  connected  with  the  bones  of 
the  cranium,  and  retain  much  longer  than 
these  their  separate  condition. 

The  nasal 
bones  (n,  n, 
jig.  127,  128) 
are  a  large 
and  elongated 
pair,  extend 
ing  from  the 
inner  side  of 
the  ant-orbital 
processes  of 
the  frontal  to 


Skull  of  a  Parrot. 


the  outer  side  of  the  ascending  processes  of  the 
intermaxillary  bones,  expanding  as  they  ad- 
vance forwards,  and  giving  off  from  their  outer 


sides  a  process  which  curves  downwards  to 
join  the  superior  maxillary  bone,  to  which  it 
has  erroneously  been  considered  to  belong. 
The  nasal  bones  soon  anchylose  with  the 
frontal,  ethrnoidal,  inter-maxillary,  and  superior 
maxillary  bones. 

The  lachrymal  or  nngueal  bones  fo,  o,  fig.  1 27, 
128,  l,Jig.  125)  are  also  of  considerable  propor- 
tionate size.  They  are  more  exposed  than  in  mam- 
malia, and  are  usually  moveably  articulated  by 
their  mesial  or  anterior  edge  to  a  varying  number 
of  the  bones  of  the  skull.  These  are  commonly 
the  frontal,  nasal,  and  malar  bones;  but  in  the 
ostrich  the  lachrymal  articulate  with  the  palatine 
bones ;  in  the  Parrot  they  extend  backwards 
beneath  the  orbit  to  the  post-orbitals,  and  thus 
complete  the  bony  circumference  of  that 
cavity,  while  in  the  Owls  they  do  not  at  all 
articulate  with  the  frontal  bone.  They  are 
smallest  in  the  Rasores  and  Natatores,a.nd  attain 
their  greatest  development  in  the  diurnal  Rap- 
tores.  In  these  the  separated  supra-orbital 
bones  give  additional  protection  to  the  eye, 
over  which  they  form,  in  conjunction  with  the 
lachrymal,  the  projecting  arch  so  characteristic  of 
the  physiognomy  of  the  bird  of  prey. 

The  palatine  bones  (p,  p,jig.  126,)  are  of  great 
proportional  size  :  each  is  of  an  elongated, 
slender,  depressed  figure,  becoming  narrower 
anteriorly,  forming  the  posterior  part  of  the  pa- 
latine arch,  and  completing  with  the  vomer  the 
boundary  of  the  posterior  nostrils.  In  the  Rap- 
tores  the  palatine  bones  are  united  together 
only  by  a  small  part  of  their  anterior  extre- 
mities. In  the  Owls  the  posterior  extremities 
are  widely  separated  from  each  other.  In 
the  Imessores  they  are  not  united  together  in 
any  part  of  their  extent,  except  in  the  Gross- 
beak,  (Loxia  Coccothraustcs,)  at  the  anterior 
extremity.  In  this  bird  and  in  the  Parrots,  the 
palatine  bones  have  not  a  horizontal  but  a  ver- 
tical position,  contrary  to  what  they  are  in 
most  other  birds.  They  are  least  developed 
in  the  Rasores. 

Thevotner  (q,fig.  126)  is  rapidly  an chylosed 
in  the  Ostrich  with  the  sphenoid,  appear- 
ing as  a  long,  moderately  compressed,  pointed 
process,  extending  forward  from  the  spine  of 
the  sphenoid  in  the  interval  of  the  palatine 
bones,  and  dividing  the  posterior  aperture  of 
the  nose  into  two  lateral  halves.  In  most  other 
birds  it  remains  distinct  from  the  spine  of  the 
sphenoid,  as  it  is  also  in  the  ostrich  at  a  very 
early  period. 

The  intermaxillary  bone  (m,Jlg.  125,  r,  r, 
fig.  126,  127,  128)  determines  the  form,  and 
constitutes  the  greater  part,  of  the  upper  man- 
dible. It  consequently  presents  considerable 
variety  in  its  figure  and  proportions,  and  also 
in  its  mode  of  articulation,  in  different  birds ; 
but  in  every  species  it  is  of  considerable  size. 
When  completely  ossified,  which  it  is  at 
a  very  early  period,  the  intermaxillary  bone 
consists  of  three  processes  which  diverge  from, 
or  unite  to  form,  the  extremity  of  the  upper 
mandible :  the  superior  mesial  process  or  nasal 
plate  is  lamellate,  depressed  or  flattened  hori- 
zontally, extends  backwards  between  and  above 
the  lower  ends  of  the  nasal  bones,  and  becoming 

T2 


•276 


AVES. 


wedged,  as  it  were,  between  their  upper  ends,  is 
articulated  in  general  by  an  anchylosis  to  them 
and  the  ethmoid  bone.  This  union,  however, 
always  allows  of  a  certain  elastic  or  yielding 
motion  to  pressure  from  below.  In  the  Parrots, 
where  the  upper  mandible  is  an  important  in- 
strument in  their  climbing  habits,  the  nasal  plate 
of  the  intermaxillary  bone  is  joined  to  the  era- 
mum  by  a  ligamentous  substance  (II,  Jig.  128). 
The  two  lateral  or  mandibular  processes  (r,  r, 
Jig.  127)  of  the  intermaxillary  bones  diverge  and 
extend  backwards,  external  and  superior  to  the 
superior  maxillary  bones  ;  and,  in  the  Ostrich, 
they  articulate  with  the  anterior  extremities  of 
the  malar  or  zygomatic  bones.  Throughout 
their  whole  course  the  mandibular  processes 
are  in  close  contact  with,  and  soon  become  an- 
chylosed to  the  superior  maxillary  bones.  The 
ossification  of  the  intermaxillary  bone  obeys  the 
ordinary  law  of  centripetal  development.  The 
lateral  moieties  are  still  separate  in  the  chick 
at  the  conclusion  of  incubation;  and  in  the 
duckling  they  do  not  anchylose  until  six  weeks 
after  that  period.  The  union  commences  at 
the  anterior  extremity,  while  at  the  opposite 
or  cranial  end  of  the  nasal  process,  traces  of  the 
original  separation  may  frequently  be  observed 
in  the  full-grown  bird ;  these  are  very  con- 
spicuous in  the  Gulls,  (Laridee). 

The  superior  maxillary  bones  (s,  s,  Jig.  126, 
127)  are  very  seldom  united  together  in  birds. 
They  are  comparatively  of  small  size.  Each 
may  be  said  to  commence  mesiad  of  the  ori- 
gin of  the  mandibular  processes  of  the  in- 
termaxillary bone ;  it  then  expands  as  it  pro- 
ceeds backwards,  and,  opposite  the  anterior 
end  of  the  palatine  bone,  divides  into  two 
processes.  The  mesial  or  palatine  process  ex- 
tends along  the  outside  of  the  palatine  bone, 
and  soon  becomes  anchylosed  to  it;  the  ex- 
ternal or  malar  process  is  articulated  obliquely 
to  the  under  part  of  the  anterior  moiety  of  the 
zygomatic  bone.  At  the  origin  of  this  process 
a  small  projection  meets  the  descending  pro- 
cess of  the  nasal  bone.  In  most  Gallinaceous 
birds,  the  body,  or  part  anterior  to  the  palatine 
and  zygomatic  processes,  is  wanting;  but  in 
the  common  fowl  it  extends  towards  the 
mesial  line,  and  unites  with  the  vomer,  so  as 
to  divide  the  palatal  fissure  into  an  anterior 
and  posterior  cavity.  In  the  Ostrich,  where 
the  body  of  the  upper  maxillary  extends  for- 
wards to  the  symphysis  of  the  intermaxillary 
bone,  a  process  is  also  given  off  at  the  origins 
of  the  palatine  and  zygomatic  bones,  which 
passes  inwards  to  the  vomer,  and  completes, 
in  the  adult,  the  boundary  of  the  anterior  pa- 
latal fissure. 

The  movement  of  the  bony  framework  of 
the  upper  mandible  resulting  Yrom  the  union 
of  the  intermaxillary,  superior  maxillary,  and 
palatal  bones,  is  immediately  effected  by  the 
elongated  malar  or  zygomatic  bone,  (o,fig.  125, 
t,t,  Jig.  126,  127,  128,)  which  transfers  to 
the  zygomatic  process  of  the  superior  maxil- 
lary the  movements  of  the  tympanic  bone, 
being  so  placed  as  to  form  the  medium  of 
communication  between  these  parts.  It  ex- 
tends in  a  straight  line  from  one  to  the  other, 


this  being  the  form  best  adapted  to  resist  the 
pressure  upon  its  two  extremities.  With  the 
superior  maxillary  bone  it  is  soon  anchylosed, 
but  with  the  tympanic  bone  it  is  in  most  Birds 
articulated  by  a  moveable  ball  and  socket-joint, 
the  articular  surfaces  being  connected  by  a 
nbro-cartilaginous  substance;  in  the  Capri- 
mulgi,  however,  it  is  anchylosed  at  both  ex- 
tremities. The  malar  bone  is  commonly  of  a 
compressed  or  vertically  flattened  form,  but 
sometimes,  as  in  the  Ostrich,  it  is  cylindrical: 
It  is  originally  composed  of  two  pieces  placed 
in  a  parallel  line,  one  above  the  other;  the 
superior  being  pointed  at  both  extremities, 
and  much  smaller  than  the  other. 

The  tympanic,  pedicellate,  or  quadrate  bone 
(it  fig-  125,  e,  fig.  126,  128,)  is  never  anchy- 
losed with  the  o'ther  elements  of  the  temporal 
bone,  but  is  freely  moveable  as  in  most  of  the 
cold-blooded  ovipara;  and  it  is  interesting  to 
observe  that  in  the  rodent  quadrupeds,  which 
exhibit  many  other  affinities  to  birds,  the  tym- 
panic element  remains  for  a  long  period  a  de- 
tached bone,  but  is  situated  altogether  posterior 
to  the  maxillary  articulation.  In  birds,  where 
the  base  of  the  cranium  is  remarkably  shortened 
in  the  antero-posterior  diameter,  the  tympanic 
bone  is,  as  it  were,  thrust  forward  and  wedged 
in  between  the  inferior  maxillary  bone  and  the 
zygomatic  process  of  the  temporal,  thus  inter- 
cepting, and  articulating  with,  both  the  lower 
jaw  and  cheek-bones.  The  membrana  tympani 
continues,  however,  to  be  attached  by  about  half 
its  circumference  to  the  posterior  part  of  the  os 
quadratum,  arid  for  the  remainder  of  its  extent 
to  the  occipital  and  sphenoidal  bones. 

The  upper  end  of  the  tympanic  bone  is 
articulated  by  two  distinct  transverse  condyles 
with  the  zygomatic  portion  of  the  temporal 
bone;  below  these  it  is  contracted,  and  then 
expands  as  it  descends,  giving  off  a  strong 
process  from  the  middle  of  its  anterior  surface, 
which  projects  into  the  orbit,  then  a  smaller 
process  from  its  posterior  surface  extending 
backwards,  and  lastly,  sending  off  at  its  lower 
extremity  an  external  process  for  the  malar 
bone,  and  an  internal  one  for  the  pterygoid, 
between  which  processes  are  two  oblique  oblong 
convexities  for  the  articulation  of  the  lower  jaw. 

Having  an  immediate  connection  with  the  mo- 
tions of  the  whole  beak,  it  necessarily  presents 
varieties  of  form  in  different  birds,  without, 
however,  losing  the  characteristic  figure  which 
has  been  described.  By  whatever  cause  the 
tympanic  bone  is  carried  forwards,  whether 
by  the  action  of  the  pterygoid  muscles  in- 
serted into  its  orbitar  process,  or  by  the  pres- 
sure of  the  lower  jaw  upon  its  inferior  surface, 
that  motion  is  communicated  to  the  pterygoid 
and  malar  bones,  which  transfer  it,  the  one 
to  the  palatine,  the  other  to  the  superior  max- 
illary bones,  and  thus  the  upper  mandible 
is  elevated  at  the  same  time  that  the  lower 
one  is  depressed.  The  elasticity  of  the  union 
of  the  nasal  process  of  the  intermaxillary 
bone  with  the  cranium  restores  the  upper 
jaw  on  the  cessation  of  the  pressure  from 
below,  to  the  position  from  which  the  move- 
ment of  the  tympanic  bones  had  displaced  it. 


AVES. 


277 


These  movements  are  freely  allowed  in  most 
birds  from  the  nature  of  the  articulation  of 
the  tympanic  bone;  but  in  the  Struthious  birds 
they  are  more  restrained,  from  the  connection 
of  the  bone  with  the  descending  zygomatic 
process  of  the  temporal  bone ;  the  extent  of 
this  attachment  is  greatest  in  the  Emeu,  where 
it  almost  produces  a  complete  fixation  of  the 
tympanic  bone. 

The  inferior  maxillary  bone  (p,  Jig.  125,  v, 
jigs.  126,'  128,)  is  originally  composed  of  twelve 
distinct  pieces,  each  lateral  moiety  being  made 
up  of  six.  The  anterior  symphyseal  or  dental 
portion  of  each  ramus  first  unites  with  its 
fellow  at  the  symphysis;  the  two  portions 
which  form  the  condyle  (v,  Jig.  126)  next  an- 
chylose;  the  angular  (v,  Jig.  126),  supra- 
angular  and  opercular,  or  splenial  pieces  are 
consolidated  at  a  later  period.  The  anterior 
extremities  of  the  angular  and  supra-angular 
pieces  are  wedged  into  corresponding  grooves 
of  the  symphyseal  element ;  and  the  opercular 
portion  is  extended  like  a  splint  along  the 
inner  side  of  the  gomphosis,  by  which  the 
preceding  portions  are  united. 

The  traces  of  the  original  separation  of  these 
bones  long  remain  in  the  semi-aquatic  and  aqua- 
tic birds  (Grallatores  and  Nattitores),  which, 
as  the  lowest  of  the  class,  manifest  their  affinity 
in  this  respect  to  the  cold-blooded  Ovipara, 
where  this  complex  structure  of  the  lower  jaw 
continues  throughout  life. 

As  the  lower  jaw,  thus  constituted,  forms 
with  the  upper  jaw  the  principal  organ  of  pre- 
hension in  birds,  it  presents  many  variations 
of  form  and  magnitude,  which  immediately 
relate  to,  and  are  consequently  indicative  of 
their  mode  of  life,  food,  &c.  These  general 
modifications  will  be  treated  of  in  relation  to 
the  digestive  function,  but  some  of  the  less 
conspicuous  characters  of  the  lower  jaw  may  be 
more  appropriately  considered  in  this  place. 

The  rami  are  in  general  completely  anchylosed 
at  the  symphysis,  the  extent  of  the  united  por- 
tions varying  considerably  in  different  birds, 
but  occupying  in  most  cases  only  a  small  pro- 
portion of  the  jaw.  In  the  Pelicans  the  rami 
are  united  by  the  mere  extremities,  appearing  as 
if  bent  upon  each  other  at  the  symphysis,  and 
supporting  the  dilatable  sac  which  fills  up  the 
intermediate  space,  like  the  hoop  of  the  fisher- 
man's landing-net.  The  symphysis  is  also  of 
very  small  extent  in  most  other  Palmipeds. 
It  is  small  in  the  Rasores  and  Cursores.  In  the 
Storks  and  Cranes  it  extends  along  a  third  part 
of  the  entire  jaw.  In  the  Flamingo,  where  the 
anterior  part  of  the  jaw  is  bent  down  at  an 
obtuse  angle,  nearly  half  of  the  rami  are 
united.  In  the  Skimmers  ( Rhyncops),  Horn- 
bills,  and  Toucans,  two-thirds.  In  the  Curlew 
the  two  rami  are  in  apposition  for  two-thirds 
of  their  anterior  extent,  but  are  not  anchy- 
losed, and  form,  in  this  respect,  the  only 
known  exception  to  the  rule. 

In  diurnal  Birds  of  Prey,  in  many  of  the 
Parrot-tribe,  in  the  Herons  and  Swans,  each 
ramus  of  the  lower  jaw  forms  an  entire  bony 
plate.  In  the  rest  of  the  class  a  membranous 
unossiried  space  is  left  at  the  place  of  union 


of  the  symphyseal  with  the  angular,  supra- 
angular,  and  splenial  elements.  This  defi- 
ciency is  of  a  longitudinal  form,  and  is  always 
situated  behind  the  middle  of  the  ramus. 
In  the  Bustards,  Woodcocks,  Curlews,  Gulls, 
Skimmers,  Guillemots,  Petrels,  and  Pen- 
guins, there  is  a  second  foramen,  of  a  rounder 
figure,  posterior  to  the  preceding,  and  resulting 
from  a  defective  union  of  the  angular,  supra- 
angular,  and  condyloid  pieces.  In  the  Casso- 
wary this  space  is  subdivided  into  several 
small  foramina.  In  the  Emeu  (Dromuius)  and 
Ostrich  (Struthio)  there  is  a  single  small  fora- 
men at  the  corresponding  part. 

At  the  posterior  part  of  each  ramus  the  fol- 
lowing processes  are  developed  in  various 
degrees  in  different  birds.  The  suprangular 
piece  ascends  in  a  greater  or  less  degree  in 
the  form  of  a  thin  lamina  with  a  gently  rounded 
outline,  representing  the  coronoid  process. 
From  the  inner  side  of  the  condyloid  piece 
there  extends  a  more  marked  process,  which 
may  be  called  the  internal  angular ;  and  from 
the  posterior  part  of  the  ramus  a  third  process 
is  continued,  which  may  be  termed  the  posterior 
angular  process. 

The  coronoid  process  is  most  developed  in  the 
Parrots,  Gulls,  Herons, and  Cross-bills  (Loxia), 
in  some  of  which,  as  the  Loxia  coccothraustes, 
cardinally  and  pulverulent  us,  the  lower  jaw 
presents  the  following  peculiarity.  A  large 
sesamoid  bone  of  a  triangular  form,  but 
rounded  and  transverse,  with  the  base  directed 
outwards  and  the  apex  inwards,  is  situated 
at  the  posterior  and  internal  aspect  of  the 
articular  ligament  of  the  lower  jaw.  It  com- 
pletes the  maxillary  articulation  posteriorly,  and 
corresponds  by  its  anterior  articular  surface  to 
the  posterior  part  of  the  outer  condyle.  The  ar- 
ticular surface  of  the  lower  jaw  of  the  Parrots 
is  a  simple  narrow  longitudinal  furrow,  open  at 
the  two  extremities.  That  of  the  Toucans  is 
almost  equally  simple,  but  of  a  rounder  figure. 
In  most  other  birds  the  articular  surface  is 
divided  into  two  distinct  portions,  of  which 
the  internal  is  an  oblique  concavity,  the  exter- 
nal also  oblique,  but  terminating  in  a  convex 
eminence  behind. 

In  the  Rasorial  birds  the  coronoid  process  is 
feebly  developed,  but  the  internal  and  angular 
processes  are  of  large  size.  The  latter  is  very 
remarkable  in  the  great  Cock  of  the  woods, 
( Tetrao  urogallus,)  where  it  extends  upwards 
and  backwards  in  a  curved  form  for  the  extent 
of  an  inch,  affording  attachment  to  the  power- 
ful muscles  required  to  produce  the  wide  ex- 
pansion of  the  mandibles  necessary  to  seize  the 
large  fir-cones  which  constitute  its  food.  In 
the  lamellirostral  Palmipedes  not  only  are  the 
internal,  and  the  posterior  angular  processes  of 
large  size,  but  there  are  also  two  eminences  for 
muscular  attachment  on  the  outer  side  of  each 
ramus  anterior  to  the  articular  surface.  In  the 
Gulls  an  oblique  ridge  is  continued  from  a 
single  eminence  similarly  situated. 

The  articular  capsule  of  the  lower  jaw  is 
strengthened  by  lig-amentous  fibres  arising 
from  the  lower  extremity  of  the  tympanic 
bone,  and  passing  backwards  to  be  inserted  into 


278 


AVES. 


the  outer  side  of  the  internal  angular  process. 
This  ligament  assumes  a  fibro-cartilaginous 
structure  at  its  anterior  part :  it  is  attenuated 
internally,  and  is  situated  between  the  two 
bones  in  the  outer  part  of  the  capsular  ligament. 
At  the  posterior  part  of  the  joint  a  strong 
fibrous  band  extends  from  the  end  of  the  mas- 
toid  process  to  the  internal  angular  process  of 
the  lower  jaw,  so  as  to  restrain  the  forward 
movement  of  the  jaw. 

The  skull  presents  fewer  varieties  of  form  in 
birds  than  in  any  other  class  of  vertebrate  ani- 
mals. With  the  exception  of  a  few  species,  in 
which  the  beak  assumes  what  may  almost  be 
termed  a  monstrous  development,  it  has  the 
form  of  a  pretty  regular  five-sided  pyramid,  of 
which  the  occiput  forms  the  base,  and  the  an- 
terior extremity  of  the  beak  the  apex. 

The  posterior  facet  or  base  of  the  pyramid 
is  formed  by  the  upper  and  larger  portion  of 
the  occiput,  together  with  part  of  the  temporal 
bones.  It  is  the  smallest  facet  of  the  head, 
and  is  larger  in  the  transverse  than  the  vertical 
diameter.  It  presents  the  vertical  prominence 
corresponding  to  the  narrow  cerebellum,  which 
is  separated  by  a  venous  foramen  and  furrow 
(Q,fig.  126)  from  a  broad  muscular  depression 
on  either  side ;  below  these  are  the  large  occi- 
pital foramen,  (1,  jig.  126);  the  hemispheric 
tubercle,  which  unites  the  head  to  the  atlas ; 
and  on  either  side  of  this  tubercle  a  smaller 
muscular  depression,  separated  by  a  transverse 
ridge  from  the  larger  one  above,  and  per- 
forated by  the  pneumogastric  and  hypoglossal 
nerves ;  these  depressions  are  bounded  laterally 
by  the  mastoid  processes.  (10,  W,fg.  126.) 

The  inferior  facet  or  base  of  the  skull  joins 
the  posterior  and  lateral  facets  almost  at  a 
right  angle.  It  is  bounded  anteriorly  and  at 
the  sides  by  the  lower  jaw,  which,  on  account 
of  the  compressed  form  and  divarication  of  the 
rami,  scarcely  intercepts  any  part  of  the  view 
of  this  very  complicated  surface.  The  occipital 
condyle,  with  the  muscular  depressions  on 
either  side  and  the  mastoid  processes,  may  be 
considered  in  some,  and  more  especially  in  the 
Struthious  birds,  as  forming  part  of  the  base  of 
the  skull.  Anterior  to  the  basilar  portion  of 
the  occiput  comes  the  body  of  the  sphenoid, 
which  in  the  Struthionida  sends  outwards  and 
forwards  two  rounded  processes  O.K-%- 126) 
to  abut  against  the  flattened  pterygoid  bones. 
Between  the  origins  of  these,  and  anchylosed 
to  the  spine  of  the  sphenoid,  the  vomer  extends 
forwards  to  a  distance  varying  in  different  birds. 
The  tympanic  bones  are  seen  on  either  side  of 
the  body  of  the  sphenoid,  and  external  to  these 
the  zygomatic  processes  of  the  temporal ;  the 
space  circumscribed  by  these  bones,  with  the 
mastoid  processes  behind,  forms  the  expanded 
external  passage  of  the  ear,  which  is  closed  in 
the  recent  state  by  the  large  convex  membra/no, 
tympani,  (8,  8,  fig.  126.)  Anterior  to  the 
tympanic  bones  the  pterygoid  processes  (i  i, 
fig.  126)  extend  forwards  and  inwards  to  join 
the  palatine  bones;  which  are  then  continued 
forwards  to  the  superior  maxillary,  leaving 
between  them  the  large  posterior  nasal  fissure 
divided  longitudinally  by  the  vomer.  These 


fissures  are  commonly  continuous  with  the 
anterior  palatal  fissure,  (7,  7,  fig.  126,)  but  in 
the  full  grown  Struthious  and  some  Gallinaceous 
birds,  the  palatine  and  maxillary  bones  unite 
with  the  vomer  and  separate  the  two  fissures, 
thus  increasing  the  bony  floor  of  the  nasal 
cavities.  External  to  the  rami  of  the  lower 
jaw,  the  malar  or  zygomatic  bones  may  in  ge- 
neral be  seen  converging  from  the  tympanic  to 
the  superior  maxillary  bones,  the  elongated 
triangular  space  between  these  bones  and  the 
pterygoid  and  palatine  leads  directly  from  below 
into  the  large  orbits. 

The  two  lateral  facets  present  posteriorly  the 
tympanic  or  auditory  cavity,  (8,  Jig- 128,)  ante- 
rior to  which  is  the  tympanic  bone,  with  the 
malar  and  inferior  maxillary  bones  extending 
forwards  from  its  lower  extremity.  Above  the 
tympanic  bone  is  the  zygomatic  process  of  the 
temporal,  (d,  Jig.  128,)  arching  over  it  in  the 
Struthious  and  Psittaceous  birds,  as  if  to  effect 
its  normal  connection  with  the  malar  bone. 
Between  the  zygomatic  and  post-orbital  pro- 
cesses is  the  crotaphyte  depression,  (g)t/zg.l28,) 
always  well-marked,  but  bounded  by  ridges 
more  or  less  developed  in  different  birds.  At 
the  lower  part  of  this  depression  may  be  per- 
ceived the, large  foramen  common  to  the  supe- 
rior and  inferior  maxillary  divisions  of  the  trifa- 
cial  nerve.  Then  come  the  spacious  rounded 
orbits,  bounded  above  by  the  supra-orbital 
lamella,  behind  by  the  sphenoid  and  frontal  ex- 
pansions, which  form,  at  the  same  time,  the  an- 
terior walls  of  the  cranium ;  separated  from  each 
other,  but  always  more  or  less  incompletely,  by 
the  thin  sphenoidal  and  ethmoidal  plates,  the 
deficiencies  of  which  are  supplied  in  the  recent 
state  by  aponeurotic  membranes,  and  defended 
anteriorly  by  the  largely  developed  lachrymal 
bones  and  the  ethmoidal  alee,  between  which 
there  are  always  present  apertures  varying  in 
size.  The  pterygoid  and  palatine  bones,  with 
the  styliform  malar  bone,  form  a  very  incom- 
plete floor  of  the  orbit. 

Anterior  to  the  orbits  the  sides  of  the  skull 
become  gradually  narrower  to  the  end  of  the 
beak  ;  between  the  lachrymal  and  the  superior 
maxillary  bones  a  large  triangular  or  rounded 
space  is  left,  (11,  fig.  128,)  which  conducts  to 
the  nasal  cavity.  A  second  vacancy  occurs, 
anterior  to  this,  bounded  by  the  nasal,  superior 
maxillary,  and  intermaxillary  bones,  forming 
the  osseous  boundary  of  the  wide  external 
nostrils.  (12,/g.s.  127,  128.) 

The  superior  surface  of  the  cranium  is  gene- 
rally convex  in  relation  to  and  indicative 
of  the  development  of  the  brain ;  it  is  round- 
ed posteriorly,  where  it  is  generally  widest. 
Here  on  each  side  is  seen  the  temporal  de- 
pression :  the  interorbital  space  in  the  Gulls, 
Petrels,  Albatrosses,  Penguins,  and  other  sea- 
birds,  presents  also  two  depressions,  scarcely 
less  marked,  of  a  semilunar  form,  the  convexi- 
ties meeting  in  the  mesial  line,  and  lodging  a 
gland,  whose  secretion  is  carried  into  the  nose 
to  lubricate  the  pituitary  membrane.  Slight 
traces  of  these  glandular  depressions  may  be 
seen  at  13,  fig.  127,  in  the  Ostrich.  In  other 
birds  the  interorbital  space  is  moderately  con- 


AVES. 


279 


cave  or  flattened.  Anterior  to  this  part  the 
cranium  in  the  Parrot  presents  the  moveable 
junction  of  the  upper  mandible,  but  in  other 
birds  a  continued  osseous  surface  converges 
more  or  less  gradually  to  the  end  of  the  beak, 
only  interrupted  by  the  anterior  orifices  of  the 
nasal  cavity. 

The  skull  in  the  Raptures,  especially  in  the 
nocturnal  division,  is  short,  broad,  and  high,  in 
proportion  to  its  length,  and  the  cranium  is 
large  compared  with  the  face.  The  posterior 
facet  is  convex,  and  remarkably  extended  up- 
wards and  laterally,  and  is  continued  insensibly 
at  an  obtuse  angle  with  the  upper  surface. 
The  occipital  foramen  is  almost  horizontal. 
The  temporal  fossa?  are  not  very  deep,  and  do 
not  meet  above  at  the  middle  line.  The  cere- 
bral convexities  are  not  strongly  marked  ;  the 
frontal  region  is  flat.  A  longitudinal  furrow 
extends  along  the  whole  upper  surface  of  the 
cranium,  and  is  especially  remarkable  in  the 
Owls.  The  cranium  and  face  are  separated  by 
a  sudden  contraction.  The  orbits  are  very 
complete,  on  account  of  the  development  and 
complete  junction  of  the  frontal,  ethmoidal, 
ungueal,  and  palatine  boundaries. 

The  cranium  of  the  Warblers  presents  a 
more  regular  sphericity,  but  the  interorbital 
space  is  very  concave.  The  anterior  parietes 
of  the  orbits  are  large  and  very  complete  from 
the  size  of  the  lachrymal  bone  and  of  the  trans- 
verse lamina  of  the  ethmoid  ;  the  internal  and 
posterior  bony  parietes  are,  on  the  other  hand, 
remarkably  defective;  the  optic  foramina  are 
indeed  commonly  blended  into  one,  and  con- 
tinuous with  the  larger  fissures  above. 

The  distinctive  characters  of  the  skull  of  the 
Scansores  are  the  most  remarkable,  especially 
in  the  Parrots  and  Toucans.  In  the  former 
the  upper  surface  of  the  cranium  is  flattened  or 
slightly  convex,  and  greatly  extended  in  breadth 
between  the  orbits.  These  cavities  are  very 
complete  ;  and  the  nasal  inlets  on  the  sides  of 
the  skull  are  much  limited  in  size  by  the  extent 
of  ossification.  However,  the  breadth  of  the 
posterior  part  of  the  base  of  the  cranium  and 
the  large  size  of  the  pterygoid  bones  occasion 
a  very  considerable  interval  between  these  and 
the  body  of  the  sphenoid. 

In  the  Toucans  the  cranium  slightly  in- 
creases in  breadth  to  the  anterior  part  where  it 
is  joined  to  the  enormous  bill.  Its  superior 
surface  presents  an  equable  convexity.  The 
temporal  fossae,  like  those  of  the  parrots,  are 
small,  and  wholly  confined  to  the  lateral 
aspects  of  the  cranium.  The  posterior  sur- 
face, which  is  absolutely  concave  in  the  Mac- 
caws,  from  the  backward  extension  of  the 
mastoid  processes,  is  slightly  convex  in  the 
Toucans,  where  it  is  separated  from  the  upper 
surface  by  a  regularly  arched  ridge.  The 
cerebellic  prominence  extends  over  the  occi- 
pital foramen,  the  plane  of  which  inclines 
forwards  and  downwards  from  the  horizontal 
line  at  an  angle  of  45°.  The  circumference 
of  the  orbit  is  uninclosed  by  bone  at  the  pos- 
terior part,  the  postorbital  processes  of  the 
frontal  not  being  developed  as  in  the  parrots. 
The  zygomatic  process  of  the  temporal,  with 


the  ligament  extending  between  it  and  the 
malar  bone,  forms  here  the  posterior  boundary 
of  the  orbit.  The  septum  of  the  orbits  is  very 
incomplete.  The  ungueo-maxillary  fissure  and 
the  external  nasal  apertures  are  very  small, 
arid  situated  on  nearly  the  same  perpendicular 
line,  the  nostrils  open  on  the  posterior  part 
of  the  upper  mandible,  and  the  remainder  of 
the  lateral  facet  is,  therefore,  a  smooth  entire 
osseous  surface  formed  by  the  thin  parietes  of 
the  dilated  cellular  mandibles. 

In  the  Hornbills  the  skull  presents  the  same 
characters  as  in  the  Toucans,  with  the  exception 
of  that  extraordinary  species  the  Ilelmeted 
Ilornbill  ( Bttceros  Galcatus.)  In  this  bird  the 
whole  outer  surface  of  the  skull  is  sculptured 
with  irregular  furrows  and  risings,  a  character 
which  it  presents  in  uo  other  bird,  and  which 
can  only  be  compared  to  the  surface  of  the 
skull  in  the  Crocodiles.  The  posterior  surface 
is  concave,  and  separated  by  a  strongly  deve- 
loped ridge  from  the  temporal  furrows,  which 
almost  meet  at  the  vertex.  The  bony  rim  of 
die  orbit  is  completed  by  the  extension  of  the 
zygomatic  process  of  the  temporal  to  that  of 
the  malar  bone,  which,  however,  are  not  an- 
chylosed,  but  joined  by  a  ligamentous  union. 
The  bony  septum  of  the  orbits  is  complete,  and 
formed  by  two  strong  plates,  separated  by  an 
intermediate  cellular  diploe,  except  at  the  pos- 
terior part.  The  optic  foramen  is  _directed 
transversely  outwards.  In  all  the  Hornbills 
the  malar  bone  is  moveably  connected  with  the 
maxillary  as  well  as  the  tympanic  bones,  as  in 
other  birds. 

In  the  Wood-peckers  the  cranium  is  round- 
ed, the  temporal  fossae  shallow,  the  internal 
wall  or  septum  of  the  orbits  incomplete,  but 
the  anterior  boundary  is  well  developed.  The 
posterior  facet  of  the  cranium  is  raised.  The 
superior  surface  is  traversed  by  a  wide  furrow 
extending  longitudinally  forwards,  generally  to 
the  right,  but  sometimes  also  to  the  left,  as  far 
as  the  lachrymal  bone.  It  is  in  this  furrow 
that  the  elongated  cornua  of  the  os  hyoides  are 
lodged,  which  relate  to  a  peculiar  mechanism 
hereafter  to  be  described.  In  some  of  the 
larger  species  of  Wood-pecker,  as  the  Picus 
major,  L.  the  cranial  furrow  is  more  symme- 
trical. In  the  Humming-birds  it  is  double,  the 
hyoidean  furrows  being  separated  at  first  by  the 
cerebellic  protuberance,  and  afterwards  by  a 
mesial  longitudinal  ridge. 

The  skull  in  the  Rasorial  birds  is  narrow, 
but  slightly  raised,  and  without  ridges.  In 
the  Capercailzie  ( Tetrao  Urogallus)  it  is 
almost  square,  flattened  on  the  posterior  and 
superior  surfaces,  and  impressed  with  a  con- 
siderable longitudinal  furrow  anteriorly.  The 
orbit  is  very  incomplete,  the  anterior  pa- 
rietes being  almost  entirely  wanting,  and  the 
ungueo-maxillary  vacancy  being  consequently 
continuous  with  the  orbit.  In  the  Bustards 
the  posterior  boundary  of  the  ungueo-maxillary 
fissure  is  complete,  but  in  other  respects  the 
cranium  resembles  that  of  the  Rasores. 

The  skull  is  remarkable  for  its  length  in  the 
majority  of  the  Waders.  In  the  Herons  and 
Bitterns  the  occipital  region  is  low,  and  inclines 


280 


AVES. 


from  below  upwards  and  forwards ;  it  is  sepa- 
rated from  the  upper  and  lateral  regions  by  a 
well  developed, sharp, lam bdoidal  crest;  and  it 
is  divided  into  two  lateral  moieties  by  a  slight 
longitudinal  ridge.  The  temporal  fossae  are 
deeper  and  wider  than  in  any  of  the  preceding 
orders;  and  they  now  extend  upwards,  as  in 
many  of  the  carnivorous  mammalia,  to  the  sa- 
gittal line,  along  which  an  osseous  crest  is 
developed  to  extend  the  surface  of  attachment 
of  the  temporal  muscles.  The  cranium  is  ex- 
panded, anteriorly  to  the  above  fossae,  as  if  to 
allow  of  a  compensating  space  for  the  develop- 
ment of  the  cerebral  hemispheres,  the  interspace 
of  which  is  indicated  by  a  deep  longitudinal 
furrow,  almost  peculiar  to  these  genera  of 
birds.  The  roof  of  the  orbits  is  expanded  late- 
rally, which  gives  great  breadth  to  this  part  of 
the  head,  but  the  posterior  orbital  walls  are 
very  imperfect,  and  the  internal  walls  or  septum 
almost  wholly  wanting.  The  optic  foramina 
are  blended  with  each  other  and  with  the 
smaller  foramina,  which  in  other  birds  represent 
the  foramen  lacerum  orbitale.  The  anterior 
boundary  of  the  orbits  is  also  very  imperfectly 
completed,  the  ungueo-naso-maxillary  and  an- 
terior nasal  fissures  are  not  remarkable  for  their 
extent. 

Woodcocks,  Snipes,  Curlews,  and  Lapwings, 
resemble  Herons  in  their  defective  bony  orbits ; 
but  they  want  the  extended  superior  parietes 
of  those  cavities,  and  differ  much  in  the  al- 
most spherical  form  of  the  cranium,  which  is 
smooth  and  devoid  of  the  muscular  ridges 
characteristic  of  the  fish-feeding  Gralla.  In 
this  order  the  intermaxillary  bones  present 
some  of  their  most  eccentric  forms.  They  are 
narrow,  elongated,  and  curved  downwards  in 
the  Ibises  and  Curlews ;  bent  upwards  in  the 
contrary  direction  in  the  Avosets;  extended  in  a 
straight  line  in  the  Snipes  ;  singularly  widened, 
and  hollowed  out  in  the  Boat-bill  ( Cancroma); 
widened,  flattened,  and  dilated  at  the  ex- 
tremity in  the  Spoon-bill ;  thickened,  rounded, 
and  bent  downwards  at  an  obtuse  angle  in  the 
Flamingo. 

Among  the  Natatores,  the  sea-birds,  as 
the  Divers,  (Colymbus),  Grebes,  (Podiceps), 
and  Cormorants  (Carbo),  are  characterized 
for  the  defective  condition  of  the  bony  orbits, 
and  of  the  anterior  parietes  of  the  cranium ; 
the  septum  of  the  orbits  is  almost  entirely 
wanting;  in  place  of  the  posterior  parietes 
there  are  two  lacunae  leading  directly  into  the 
cranial  cavity,  one  superior,  of  large  size, 
and  one  inferior,  smaller ;  they  are,  in 
general,  separated  by  a  narrow  osseous  bar, 
but  in  the  Coulterneb,  (Fraterculu  arctica) 
this  is  also  wanting,  so  that  all  the  anterior 
cerebral  nerves  escape  by  a  common  open- 
ing. But  in  this  species  it  must  be  observed, 
that  the  vertical  lamina  of  the  sethmoid  is 
ossified  at  its  posterior  part.  In  the  Petrels 
and  Albatrosses,  the  internal  and  posterior 
walls  of  the  orbits  are  more  complete.  In 
the  Diomedea  exulans  the  optic  foramina  are 
separated  both  from  each  other,  and  from 
the  neighbouring  outlet.  The  occipital  re- 
gion is  low,  and  divided  into  a  superior  and  an 


inferior  facet,  the  latter  being  concave  from  side 
to  side.  The  plane  of  the  occipital  foramen  is 
almost  vertical.  The  occipital  or  latnbdoidal 
crista  is  well-marked,  and  the  temporal  fossae 
nearly  approximate  in  the  middle  line.  In 
these  sea-birds  and  in  the  Gulls,  the  lateral 
lacunae  in  the  bony  parietes  of  the  face  are 
very  considerable. 

A  most  remarkable  characteristic  of  the  cra- 
nium of  both  the  Brachypterous  and  Macro- 
pterous  Sea-birds  is  the  presence  of  the  two 
deep,  elongated,  semilunar  gland  ulardepressions 
before  mentioned,  extending  along  the  roof  the 
orbits.  In  the'aquatic  birds  which  frequent  the 
marshes  and  fresh  waters,  as  the  Anatida  or 
Lamellirostres,  these  glandular  pits  are  want- 
ing, or  very  feebly  marked,  as  in  the  Swans. 
They  are,  however,  again  met  with  of  large 
size,  though  shallow,  in  the  Curlews  (Nume- 
nius)  and  Avosets  (Recurvirostra);  and  are 
also  found,  though  of  smaller  size,  in  the 
Flamingo. 

Of  the  thorax. — In  every  part  of  the  skele- 
ton of  Birds,  we  may  observe  that  there  is 
a  close  adherence  to  the  oviparous  modification 
of  the  vertebrate  type  of  structure.  This  is 
manifested  in  the  forms  and  connections  of  the 
several  vertebrae,  and  of  the  cranial  bones. 
It  is  no  less  conspicuous  in  the  structure  of 
the  thorax. 

The  ribs  are  apparently  in  moderate  num- 
ber, but  when  their  analogues  are  closely 
sought  for,  they  are  found  to  extend,  as  in 
the  Crocodile,  along  the  greater  part  of  the 
cervical  region.  In  fact  the  small  styliform 
processes  which  point  backwards  from  the 
lateral  projections  on  the  anterior  parts  of  the 
bodies  of  these  vertebras  remain  separate  after 
the  true  elements  of  the  vertebrae  have  coalesced. 
In  an  Ostrich  which  had  attained  half  its  groxvth, 
we  have  found  these  spurious  ribs  still  moveable. 
They  anchylose,  however,  with  >the  transverse 
processes  in  general  long  before  the  growth  of 
the  individual  is  completed,  excepting  towards 
the  caudal  extremity  of  the  cervical  region, 
where  comparative  anatomists,  from  this  cir- 
cumstance, have  always  found  a  difficulty  in 
determining  the  commencement  of  the  dorsal 
vertebrae.  If  the  moveable  ribs  had  com- 
menced, as  in  Mammalia,  by  extending  to  the 
sternum,  the  determination  of  their  number 
would  have  been  easy;  but  they  begin,  some- 
times by  a  gradual  and  at  others  by  a  sudden 
elongation,*  opposite  the  furculum,  from  which 
point,  either  one,  or  two,  as  in  the  Humming- 
bird, (see  p,  Jig.  125,)  terminate  by  extremities 
imbedded  in  muscle,  and  unconnected  with 
any  corresponding  portion  extending  from  the 
sternum. 

Meckel  considers  the  true  number  of  ribs 
in  the  Diurnal  Raptores  to  be  nine  pairs, 
of  the  Nocturnal  eight;  in  the  Insessores  seven 
or  eight;  in  the  Scansores  nine,  except  the 
Cuckoo,  which  has  seven  or  eight ;  in  the 

*  This  is  remarkably  the  case  in  the  Wood- 
Grouse  (  Tetrao  Urogallus),  where  the  penultimate 
and  last  cervical  ribs,  instead  of  gradually  enlarg- 
ing, diminish  in  size,  so  that  the  determination  of 
the  first  thoracic  rib  is  easy. 


AVES. 


281 


RfiKores  seven  or  eight ;  in  the  Struthiones  the 
number  of  ribs  varies  ;  in  the  Ostrich  (Stru- 
t/no) we  find  ten  pairs,  of  which  the  3d,  4th, 
5th,  and  6th,  are  articulated  with  the  sternum  ; 
in  the  Nandou  ( R/iea)  there  are  nine  pairs, 
of  which  only  the  3d,  4th,  5th,  and  6th,  are 
completed  by  sternal  portions ;  in  the  Emeu 
(Dromaius)  there  are  nine  pairs,  the  3d,  4th, 
5th,  6th,  and  7th,  being  joined  to  the  sternum; 
in  the  Cassowary  (Casuurius)  there  are  ten 
pairs,  and  of  these  the  4th,  5th,  6th,  7th,  8th, 
and  9th,  have  sternal  portions.  The  last  pair 
of  ribs  in  Strut/no  and  Rhea  are  extremely 
short,  and  abut  against  the  expanded  iliac  bones. 
Among  the  Grullutures  we  find  seven  pairs  of 
ribs  in  the  Herons  (Ardea),  and  Gigantic 
Stork  (Ciconia  Argula)  while  the  Cranes 
fGrus)  have  nine,  and  the  Coots  and  Water- 
Hens  have  ten  pairs.  In  the  Natatores,  which 
vary  so  much  in  their  locomotive  powers  and 
habits  of  life,  we  find  a  corresponding  variety 
in  the  number  of  ribs ;  in  the  Willock  (Uria 
troilc)  there  are  twelve  pairs,  and  in  the  Guil- 
lemots and  allied  sea-birds  eleven;  in  the 
Swans  eleven  ;  in  the  Penguins  nine,  of  which 
six  are  articulated  with  the  sternum. 

The  true  ribs  are  not  joined  to  the  sternum 
by  elastic  cartilages,  but  by  straight  osseous 
portions,  called  sternal  ribs,  (q,  jig.  125, 
h,  Jig.  129,)  which  are  moveably  connected  at 
both  their  extremities.  These  are  the  centres 
upon  which  the  respiratory  motions  hinge ;  the 
angle  between  the  vertebral  and  sternal  ribs, 
and  between  these  and  the  sternum  becoming 
more  open  in  inspiration,  and  the  contrary 
when  the  sternum  is  approximated  to  the  dorsal 
region  in  expiration. 

As  the  ribs  are  traced  backwards,  their 
vertebral  extremities  are  seen  to  become  gra- 
dually double  or  bifurcated  from  the  in- 
creasing development  of  the  part  answering 
to  the  cervix  and  head  of  the  rib  in  Mam- 
malia. The  spurious  cervical  ribs  may  be 
plainly  seen  to  be  articulated,  like  the  pos- 
terior spurious  ribs  of  the  Cetacea,  by  the 
-tubercle  only;  and,  as  they  increase  in  length 
in  the  proximity  of  the  thorax,  the  head  of  the 
rib  is  then  seen  to  be  thrown  downwards  to 
join  a  distinct  tubercle  on  the  side  of  the  body 
of  the  vertebra  close  to  its  anterior  margin, 
but  without  encroaching  on  the  intervertebral 
space.  The  comparative  immobility  of  the 
dorsal  vertebrae  allows  of  this  mode  of  articu- 
lation ;  but  it  is  an  interesting  circumstance 
that  in  the  Ostrich,  where  the  costal  vertebra? 
preserve  their  mobility,  the  heads  of  the  ribs, 
at  least  of  those  of  the  anterior  ones,  evidently 
pass  forwards  to  the  intervertebral  space.  The 
tubercle  of  the  rib  has  thus  less  the  character 
of  a  subordinate  process  than  in  the  ribs  of 
mammalia ;  it  is  supported  on  a  pedicle,  and 
is  articulated  by  a  simple  synovial  joint  with 
the  transverse  process  of  the  correspond  ing  ver- 
tebra. The  ribs,  below  the  union  of  the  two 
articular  processes,  are  thick  and  strong,  but 
they  gradually  become  flattened,  and  increase 
in  breadth  as  they  descend  towards  the  sternum. 
This  is  especially  remarkable  in  the  second, 
third,  and  fourth  ribs  of  the  Woodpecker. 


The  dorsal  ribs  are  not  only  connected  together 
by  muscles  and  aponeurotic  membranes,  but 
cooperate  with  the  anchylosed  dorsal  vertebrae, 
in  giving  stability  to  the  trunk  by  means  of 
small  osseous  splints,  detached  from  the  pos- 
terior margin  of  each  true  rib,  and  directed 
backwards  and  upwards  to  the  next  in  suc- 
cession, to  both  of  which  they  are  united  by 
means  of  oblique  fibrous  ligaments.  In  birds 
of  powerful  flight  these  connecting  pieces  are, 
as  might  be  expected,  most  developed.  In 
the  Raptores  they  extend  beyond  and  overlap 
the  succeeding  posterior  rib,  and  in  this  order 
they  are  anchylosed. 

In  some  of  the  Struthious  birds,  as  the 
Ostrich  and  Rhea,  they  exist  from  the  third  to 
the  fifth  rib,  while  in  the  Emeu  and  Cassowary 
there  are  only  rudimentary  traces  of  them. 
In  the  Penguins  these  accessory  processes  are 
remarkable  for  their  breadth,  but  they  are 
never  anchylosed  to  the  ribs,  and  consequently 
are  apt  to  be  lost  if  care  be  not  taken  in  pre- 
paring the  skeleton. 

The  sternal  ribs  (h,  h,fig.  129)  are  of  a  less 
flattened  form  than  the  vertebral ;  they  increase 
in  length  as  they  are  situated  further  back ; 
their  costal  extremity  is  simply  rounded,  while 
their  sternal  extremity  is  extended  transversely 
and  divided  into  two  smooth  surfaces  moveably 
articulated  by  two  synovial  capsules  with  cor- 
responding cavities  in  the  sides  of  the  sternum. 
The  first  sternal  rib  is,  however,  joined  by 
fibre-cartilaginous  substance  only,  while  one 
or  two  of  the  posterior  pieces  are  anchylosed 
with  the  rib  immediately  preceding  them,  and 
do  not  reach  the  sternum.  In  the  Ostrich 
the  last  rib  abuts  against  the  ilium,  to  which  it 
is  anchylosed. 

In  the  Peacock,  Pintado,  and  common  Fowl, 
the  vertebral  and  sternal  portions  of  the  last 
pair  of  ribs  are  unconnected  with  each  other; 
the  latter  thus  representing  the  ossified  ten- 
dinous intersections  of  the  rectus  abdominis 
muscle,  as  in  the  Crocodile.  This  analogy  is 
still  more  striking  in  the  Herons,  Storks,  and 
Curlews,  and  in  many  of  the  Natatores,  in 
which  the  sternal  portions  alone  exist,  and  are 
remarkably  elongated. 

The  part  of  the  skeleton  which  has  undergone 
the  most  remarkable  modifications  in  relation 
to  the  powers  and  functions  of  the  anterior  ex- 
tremities is  the  sternum,  ( r,s,  fig.  125  and  129,) 
which  gives  origin  to  their  principal  muscles. 
It  is  so  developed,  both  in  length  and  breadth, 
as  to  extend  over  the  whole  of  the  anterior  or 
ventral  aspect  of  the  thoracic  and  of  a  great 
part  of  the  abdominal  cavities,  reaching  in 
some  birds  of  great  powers  of  flight  even  to 
the  pubic  bones,  so  as  to  require  removal  be- 
fore the  abdominal  cavity  can  be  examined. 

In  order  to  afford  origin  to  the  accumulated 
fasciculi  of  the  pectoral  muscles,  which  other- 
wise would  become  blended  together  over 
the  middle  of  the  sternum,  an  osseous  crest 
(s,  Jig.  125,  a,  Jig.  130)  is  extended  down- 
wards, analogous  to  the  cranial  crest  which 
intervenes  to  the  temporal  muscles  in  the 
carnivorous  mammalia ;  and  as  this  crest  in- 
dicates in  these  the  powers  of  the  jaw,  so  the 


282 


AVES. 


sternal  keel  bespeaks  the  strength  of  the  ante- 
rior extremity  in  the  bird. 

Besides  the  difference  of  form  and  deve- 
lopment of  the  mesial  crest  or  keel,  the  ex- 
tended sternum  presents  many  other  varieties 
in  the  different  orders  and  families  of  birds. 
A  zoological  arrangement  of  the  class  has  even 
been  founded  on  the  modifications  of  this  cha- 
racteristic and  important  part  of  the  skeleton. 
In  every  species  the  sternum  is  more  or  less 

Fig.  129. 


Sternum,  coracoida,  and  clavicles  of  a  Woodpecker. 

quadrilateral,  more  or  less  convex  outwardly, 
and  each  of  its  margins  affords  distinctive 
characters.  The  anterior  margin  presents  two 
grooves  (b,  b,  figs.  129,  130)  extending  along 
the  greater  part  of  either  side,  and  affording  a 
secure  articulation  to  the  coracoid  bones ;  and 
in  many  birds  it  sends  forward  a  process  from 
the  middle  part  where  the  two  grooves  meet, 
as  in  the  Woodpecker  and  Penguin  (e,  fig. 
129).  This  mesial  process  we  shall  term  the 
manubrial  process,  since  it  is  analogous  to  that 
which  extends  from  the  manubrium  or  first 
sternal  bone  of  the  seal,  mole,  &c. 

The  lateral  margins  are  straight  and  excavated 
anteriorly,  to  a  greater  or  less  extent,  for  the 
lodgement  of  the  sternal  ribs.  In  some  birds 
a  process  (d,jigs.  129,  130)  is  given  off  at 
each  angle  of  the  union  of  the  lateral  with  the 
anterior  margin-  as  this  process  seems  to 
supply  the  sternal  portions  of  the  anterior 
floating  ribs,  it  may  be  termed  the  costal 
process. 

The  posterior  margin  is  most  varied  in  its 
contour,  and  is  in  general  interrupted  by  fis- 
sures, (f,f,Jigs.  129,  130.)  which  are  always 
symmetrical  in  their  position,  but  vary  in 
number  and  depth,  so  that  this  margin  is  some- 
times represented  by  the  extremities  of  three 
or  five  long  processes. 

In  the  Diurnal  Raptores  the  sternum  is  a 
large  elongated  parallelogram,  convex  both  in 


the  direction  of  its  length  and  breadth,  but 
especially  in  the  latter  sense.  The  manubrial 
process  is  thick,  the  contour  of  the  keel 
convex,  and  its  margin  extended  laterally. 

In  the  Eagles  and  Secretary-bird  the  ster- 
num is  entire,  but  in  the  Vultures  and  Hawks 
it  is  pierced  on  either  side  by  a  small  round 
aperture  situated  near  the  posterior  margin. 
Ossification  sometimes  extends  along  the  apo- 
neurotic  membrane  stretched  over  this  aperture 
so  as  to  divide  it  into  two,  as  has  been  ob- 
served in  the  Buzzard;  or  so  as  to  obliterate  it  on 
one  side  only,  as  seen  by  Meckel  in  the  Kite. 

In  the  Nocturnal  Raptores  the  sternum  is 
short,  convex  as  in  the  preceding  tribe,  but 
weaker :  there  is  no  manubrial  process.  The 
keel  is  less  developed,  its  margin  less  convex, 
and  not  thickened.  The  posterior  margin  is 
concave  and  presents  two  fissures,  separated 
by  a  middle  process,  except  in  the  common 
Darn  Owl  ( Strix  flammca )  where  it  is  wanting, 
and  a  large  but  shallow  fissure  is  found  in- 
stead. 

The  greater  part  of  the  Insessorial  Birds  are 
characterized  by  the  following  form  of  sternum. 
It  is  large,  a  little  longer  than  broad,  and 
pinched  in,  as  it  were,  at  the  sides,  just  behind 
the  costal  margin.  The  keel  is  prominent  and 
convex  along  its  inferior  margin  ;  its  anterior 
margin  is  slightly  excavated,  and  terminates 
below  in  a  slightly  projecting  angle.  The  ma- 
nubrial process  is  compressed,  prominent,  and 
curved  upwards ;  the  costal  processes  are  mo- 
derately developed.  The  posterior  margin  pre- 
sents a  single  deep  fissure  OB  either  side,  and 
a  single  lateral  process,  the  extremity  of  which 
is  constantly  dilated.  The  lateral  margins  are 
slightly  excavated. 

In  the  CorvidfS  the  keel  is  more  excavated 
at  its  anterior  margin ;  the  manubrial  process 
is  stronger,  and  is  bifurcated  at  the  extremity ; 
the  posterior  fissures  are  shallower ;  the  angular 
processes  directed  outwardly  and  not  dilated 
at  the  extremity.  In  the  Swallows  (Hirun- 
do)  the  sternum  is  large  and  the  keel  greatly 
developed ;  there  are  two  posterior  fissures, 
but  they  are  still  shallower  than  in  the  Crows}; 
the  angular  processes  are  not  dilated  at  the 
extremities.  In  the  Swifts  (Cypselus)  the 
sternum  is  entire,  and  corresponds  in  its  pro- 
portional magnitude  with  the  superior  length 
and  power  of  wing  which  characterizes  this 
genus.  The  manubrial  process  is  wanting,  but 
the  costal  processes  are  moderately  long  and 
pointed. 

In  the  Humming-birds,  which  sustain  them- 
selves on  the  wing  during  the  greater  part  of 
the  day,  and  hover  above  the  plant  while  ex- 
tracting its  juices,  the  sternum  (r,  s,  Jig.  125,) 
is  still  further  developed  as  compared  with  the 
body ;  it  approaches  to  a  triangular  form,  ex- 
panding posteriorly,  where  the  margin  is  entire, 
and  rounded.  The  depth  of  the  keel  exceeds 
that  of  the  entire  breadth  of  the  sternum.  The 
coracoid  depressions  are  deep  and  approxi- 
mated ;  the  manubrial  process  is  small,  but 
evident,  and  directed  upwards  ;  the  costal  pro- 
cesses are  also  present,  but  of  small  size. 

In  the   Creepers   (Certhia)  and    Hoopoes 


AVES. 


283 


(Upupa)j  the  sternum  again  becomes  dimi- 
nished in  size,  and  presents  the  two  fissures  on 
the  posterior  margin ;  the  keel  is  moderately 
developed  ;  the  manubrial  process  is  produced 
anteriorly ;  it  is  of  a  compressed  form  in  the 
Hoopoe,  but  thick,  and  bifurcate  in  the 
Creepers ;  there  are  no  costal  processes. 

In  the  Wood-peckers  the  keel  of  the  ster- 
num is  more  feebly  developed,  its  inferior 
margin  is  straight,  and  the  angle  formed  by  its 
union  with  the  anterior  margin  truncate.  The 
manubrial  process  enlarges  as  it  advances 
forwards,  and  is  bifurcate  at  the  extremity. 
The  co.stal  processes  are  also  long,  and  curved 
forwards;  the  posterior  margin  has  four  deep 
notches  (ff,fig.  129> 

In  the  Trogons,  Hollers  (Coracias),  King- 
fishers, Bee-eaters  (Merops),  Toucans,  and 
Touracos,  the  sternum  is  characterized  by  two 
fissures  on  either  side  at  the  posterior  margin. 

J  n  the  Parrot  tribe  the  sternum  again  singu- 
larly  resembles  in  its  integrity  that  of  the  higher 
Raptor&fbeing  in  some  species  simply  perforated 
on  either  side  near  the  posterior  margin,  and  in 
others  wholly  ossified.  It  is,  however,  narrower 
in  proportion  to  its  breadth.  The  keel  is  well 
developed,  its  inferior  margin  concave,  its  an- 
terior one  describing  a  sigmoid  flexure ;  their 
angle  of  union  rounded.  The  costal  depres- 
sions occupy  almost  the  entire  lateral  margins 
of  the  sternum.  The  manubrial  process  is 
slightly  developed,  trihedral,  and  truncate  at 
the  extremity. 

In  the  Pigeons,  which  unite  the  In- 
sessorial  to  the  Gallinaceous  order,  the  ster- 
num is  narrow,  but  the  keel  is  deep,  with  its 
inferior  border  convex,  and  the  anterior  one 
curved  forwards,  thin  and  trenchant ;  the  ma- 
nubrial process  is  strong  and  bifurcated;  the 
costal  processes  short.  The  posterior  margin 
is  cleft  by  two  fissures  on  either  side  of  the 
mesial  plane,  the  lateral  and  superior  fissures 
being  the  deepest ;  the  mesial  ones  are  occasion- 
ally converted  into  a  foramen.  The  costal  surface 
of  the  lateral  margin  is,  as  in  the  Gallinaceous 
birds,  of  very  little  extent.  In  the  Crown 
Pigeon  the  superior  fissures  are  so  deep  and 
wide  as  to  convert  the  rest  of  the  lateral  margin 
into  a  mere  flattened  process,  which  is  dilated 
at  the  extremity. 

In  the  true  Kasores  the  four  posterior  fis- 
sures of  the  sternum  are  so  deep  and  wide 
from  its  defective  ossification,  as  to  give  to  the 
lateral  parts  of  this  bone,  or  hypo-sternal 
elements,  the  appearance  of  a  bifurcated  pro- 
cess extending  backwards  from  the  costal 
margin.  The  mesial  fissures  are  here  the 
deepest,  extending  as  far  as  the  anterior 
border  of  the  keel.  This  part  is  short,  straight, 
or  very  slightly  convex  inferiorly;  concave  at 
the  anterior  margin,  which  is  formed  by  two 
ridges  which  converge  to  it  from  the  anterior 
margin  of  the  sternum.  This  margin  is  con- 
vex laterally,  and  largely  excavated  for  the 
coracoid  bones;  the  depressions  are  continuous 
with  each  other,  and  the  compressed  manubrial 
process,  arching  over  the  canal,  converts  it  into 
a  foramen.  The  costal  processes  are  prolonged 
upwards  and  forwards ;  the  posterior  lateral 


processes  pass  backwards  exterior  to  the  ribs, 
supporting  them  in  the  Capercailzie,  like  a 
semi-hoop  ;  these  processes  are  dilated  at  their 
extremities. 

In  the  Grallatores  or  Waders  the  sternum 
corresponds  in  size  to  the  shortness  of  the 
thoracic-abdominal  cavity.  In  the  Ardeida 
the  grooves  of  the  anterior  surface  pass  reci- 
procally beyond  the  middle  line,  increasing  the 
surface  of  attachment  for  the  expanded  lower 
and  posterior  extremities  of  the  coracoid  bone. 
In  most  of  the  genera  the  posterior  margin  pre- 
sents a  single  fissure  on  either  side ;  these  in 
the  Storks  and  Herons  are  wider  at  the  com- 
mencement than  at  the  termination.  In  the  Plo- 
vers, Woodcocks,  Avosets,  and  Oyster-catchers, 
it  occupies  the  whole  breadth  of  the  sternum. 
In  the  Curlews,  Ibises,  and  Spoonbills,  there 
are  two  fissures  on  either  side.  In  the  Coots, 
and  Water-hens  the  single  fissures  on  either 
side  of  the  keel  are  long  and  narrow,  and  the 
lateral  portions  of  the  sternum  extend  back- 
wards beyond  the  middle,  and  become  larger 
towards  their  extremities. 

Among  the  Natatores,  the  Albatrosses, 
Petrels,  Pelicans,  and  Cormorants  present  a 
strong  wide  convex  sternum,  similar  to  the 
Storks  and  Herons;  the  keel  is  moderately 
developed,  but  prolonged  anteriorly ;  the  pos- 
terior margin  presents  a  single  slight  fissure 
on  either  side.  In  the  Penguins,  these  fissures 
are  of  considerable  extent  (f?f,fig-  130,)  ;  but 
the  keel  of  the  sternum  is  well  developed, 
even  in  the  Aptenodytes  ;  its  inferior  border  is 
straight.  In  the  Gulls  and  Sea-swallows  the 
sternum  is  of  large  size,  wide,  arid  convex ; 
it  presents  posteriorly  two  small  and  shallow 
fissures  on  either  side,  of  which  the  lateral  and 
superior  are  sometimes  converted  into  foramina. 
The  keel  extends  along  the  whole  of  the  ster- 
num, but  is  of  moderate  depth,  and  convex 
inferiorly. 

In  the  Anatida  or  Lamellirostral  tribe  the 
sternum  is  thin,  but  of  large  size,  very  convex 
transversely,  and  much  elongated.  The  keel 
is  of  moderate  depth,  and  of  a  triangular  form, 
its  inferior  margin  being  straight ;  there  is  only 
one  fissure  on  either  side  posteriorly.* 

In  the  Divers  (Colymbus)  the  portion  of 
sternum  intermediate  to  the  two  fissures  is  pro- 
longed beyond  the  lateral  pieces,  and  the  ma- 
nubrial process  is  strongly  developed,  and  of  a 
rounded  form ;  the  whole  bone  is  remarkable 
for  its  length.  In  the  Grebes  the  sternum  is 
characterized  by  a  third  mesial  fissure  of  a 
chevron  figure  intermediate  to  the  two  ordinary 
fissures  of  the  posterior  margin. 

The  sternum  of  the  Cursorial  Birds  pre- 
sents few  affinities  of  structure  to  that  of  the 
rest  of  the  class,  resembling  rather  the  ex- 
panded plastron  or  abdominal  plate  of  the 
Tortoises.  It  has  neither  a  keel,  nor  manu- 
brial, nor  costal  processes,  and  may  be  com- 
pared to  a  square  shield.  It  is  most  convex 
in  the  Rhea,  and  least  so  in  the  Ostrich ; 


*  The  modifications  of  the  sternum  in  relation  to 
the  folded  trachea  will  be  treated  of  in  the  article 
on  the  Organs  of  Voice. 


284 


AVES. 


in  the  latter  there  may  be  observed  slight  indi- 
cations of  the  two  ordinary  posterior  fissures. 

The  ossification  of  the  perfect  sternum  of 
the  Bird  commences  from  five  centres,  —  a 
middle  one  which  supports  the  keel,  termed  by 
by  Geoffrey  St.  Hilaire  the  entosternal  (a,  fig. 
129);  two  anterior  lateral  pieces,  the  hyoster- 
nals  (b,  bj  Jig.  1 29),  and  two  posterior  lateral 
pieces,  the  hyposternals  (c  c,  fig.  129).  The 
posterior  cartilaginous  appendages  he  terms 
xiphi-sternals  (g  g,fg.  129,  130).  If  to  these 
be  added  the  two  portions  or  episternals  of 
which  he  supposes  the  manubrial  process  to 
be  composed,  then  nine  elements  may  be 
reckoned  to  enter  into  the  composition  of  the 


the  coracoid  element  has  been  err  neously  re- 
garded as  the  clavicle,  in  consequence  of  its 
being  moveably  articulated  with  the  scapular 
piece.  In  the  Emeu  (  Dromaius)  it  is  interesting 
to  observe  that  the  clavicle  commences  by  a  dis- 
tinct ossification,  and  long  continues  separate ; 
it  does  not  reach  the  sternum,  but  holds  the 
same  relative  situation  as  the  continuous  acro- 
mial  or  clavicular  process  of  the  scapula  in  the 
other  Struthious  birds. 

The  scapula  (t,  fig.  125,  A,  fig.  130)  is 
most  readily  recognised  as  such,  in  the  Pen- 
guins of  the  genus  Aptenodytes,  where  it  is 
broader  and  flatter  than  in  any  other  bird  :  in 
these,  however,  it  is  of  considerable  length  in 


Fig.  130. 


sternum;  but,  hitherto,  we  have  only  met 
with  a  single  ossific  centre  in  the  manubrial 
process.  Where  the  keel  is  absent,  as  in  the 
Cursores,  the  entosternal  piece  appears  to  be 
wanting,  and  the  ossification  of  the  sternum 
here  radiates  from  lateral  centres  only. 

Of  the  anterior  extremity. — The  bones  of 
the  anterior  extremity  do  not  present  that  ex- 
traordinary development  in  the  bird  that  might 
be  expected  from  the  powers  of  the  member 
of  which  they  are  the  basis.  The  great  expanse 
of  the  wing  is  here  gained  at  the  expense  of  the 
epidermoid  system,  and  not  exclusively  pro- 
duced by  folds  of  the  skin  requiring  elongated 
bones  to  support  them,  as  in  the  Bats,  Dragons, 
and  Flying-fish.  The  wing-bones  are,  however, 
both  in  their  forms  and  modes  of  articulation, 
highly  characteristic  of  the  powers  and  appli- 
cation of  the  muscular  apparatus  requisite  for 
their  due  actions  in  flight. 

The  bones  of  the  shoulder  consist,  on  each 
side,  of  a  scapula  (h,  fig.  1 30),  a  coracoid 
bone  ( i),  and  a  clavicle  (k), — the  clavicles 
being  mostly  anchylosed  together  at  their  mesial 
extremities,  constitute  a  single  bone,  which,  from 
its  peculiar  form,  is  termed  the  os  furcator ium 
or  furculum.  In  the  Ostrich  the  two  clavicles 
are  distinct  from  each  other,  but  are  severally 
anchylosed  with  the  coracoid  and  scapula,  so  as 
to  form  one  bone  on  either  side.  In  almost 
every  other  species  of  bird  the  scapula,  coracoid, 
and  clavicle  remain  separate  or  moveably  articu- 
lated throughout  life.  In  the  American  Ostrich 
(Rhea)  and  Java  Cassowary  (Casuarius) 
the  acromial  element  or  clavicle  is  anchylosed 
with,  or  rather  is  a  continuous  ossification  from, 
the  scapula ;  but  the  coracoid  bone  is  free ; 
and  this  condition  is  worthy  of  notice  as  it 
i's  precisely  that  which  the  bones  of  the  shoul- 
der present  in  the  Chelonian  Reptiles;  where 


proportion  to  its  breadth,  and  does  not  exhibit 
any  trace  of  spinous  process.  In  the  rest  of  the 
class  it  is  a  simple  narrow  elongated  bony 
lamina,  increasing  in  thickness  as  it  approaches 
the  joint  of  the  shoulder ;  there  it  is  extended 
in  the  transverse  direction,  forming  externally 
the  posterior  half  of  the  glenoid  cavity, and  being 
internally  more  or  less  produced  to  meet  the 
clavicle,  while  it  is  strongly  attached  in  the  re- 
mainder of  its  anterior  surface  to  the  coracoid 
bone.  The  position  of  the  scapula  is  longitudi- 
nal,being  extended  backwards  from  the  shoulder, 
parallel  to  the  vertebral  column,  towards  which, 
however,  it,  in  general,  presents  a  slight  convex- 
ity. In  birds  of  strong  powers  of  flight,  as  in  the 
Swift,  (Cypselus,)  it  reaches  to  the  last  rib, 
while  in  the  Emeu,  on  the  contrary,  it  extends 
over  two  ribs  only.  In  the  Humming-bird 
(Trochilus)  its  posterior  third  is  bent  down- 
wards at  a  slight  angle. 

The  coracoid (u,fig.\ 25, i,fgs.  129,  130),  or 
posterior  clavicle,  is  always  the  strongest  of 
the  bones  composing  the  scapular  arch  :  its  ex- 
panded extremity  is  securely  lodged  below 
in  the  transverse  groove  at  the  anterior  part  of 
the  sternum,  from  which  it  extends  upwards, 
outwards,  and  forwards,  but  frequently  al- 
most in  the  vertical  position  to  the  shoulder - 
joint,  where  it  is  united  at  an  acute  angle  with 
the  scapula  and  clavicle.  It  thus  forms  the 


AYE'S. 


285 


main  support  to  the  wing,  and  the  great  point 
of  resistance  to  the  humeri  during  the  down- 
ward stroke  of  this  aerial  oar.  The  superior  or 
humeral  end  of  this  bone  is  commonly  bifur- 
cate ;  the  outer  process  is  the  strongest,  and 
completes  the  glenoid  cavity  anteriorly,  (I, 
Jig.  1 30,)  above  which  it  rises,  to  a  greater  or  less 
extent,  and  affords,  on  its  inner  side,  an  arti- 
cular surface  for  part  of  the  acromial  end  of  the 
clavicle  :  the  inner  process  is  short  and  com- 
pressed, and  is  also  joined  by  ligament  to  the 
acromial  end  of  the  clavicle.  Just  below  the 
origins  of  these  processes  an  articular  surface 
extends  transversely  across  the  posterior  part  of 
the  coracoid  bone  by  which  it  is  firmly  united 
by  fibro-cartilaginous  substance  to  the  scapula. 
The  glenoid  cavity  resulting  from  the  union  of 
these  two  bones  is  not,  however,  always  equal 
to  the  reception  of  the  entire  head  of  the  hu- 
merus.  In  the  birds,  which  Mr.  Vigors  re- 
gards as  composing  the  typical  orders  of  the 
class,  viz.  the  Rap  tores  and  Insessores,  (the 
aves  aerete  of  Nitzsch,)  a  small  but  distinct  bone 
extends  between  the  scapula  and  coracoideum 
along  the  superior  part  of  the  articular  cavity  for 
the  humerus,  which  it  thus  completes.  Nitzsch, 
the  discoverer  of  this  element  of  the  scapular 
apparatus,  denominates  it  the  capsular  bone, 
(Schulterkapselbeine)  ;  by  Meckel  it  is  called 
the  Os  humcro-scapulare,  and  is  regarded  as 
the  analogue  of  the  scapula  inferior  of  reptiles. 
In  the  Aberrant  orders  of  birds,  as  the  Rasoi^es, 
Grallatores,  and  Natatores,  there  is,  in  place 
of  this  bone,  a  strong  elastic  ligament  or  fibro- 
cartilage  extended  between  the  scapula  and 
coracoideum,  against  which  that  part  of  the 
head  of  the  humerus  rests,  which  is  not  in  con- 
tact with  the  glenoid  cavity. 

The  clavicles  (v,  fg.  125,  b,  Jig.  130)  in 
birfls,  as  in  the  mammalia,  are  the  most  variable 
elements  of  the  scapular  apparatus.  In  the 
Ground  Parrots  of  Australia  ( Pezophorus,  II- 
liger)  they  are  rudimentary  or  wholly  deficient  ;* 
they  are  represented  by  short  processes  in  the 
Emeu,  Rhea,and  Cassowary;  they  do  not  come 
in  contact  inferiorly  in  the  Ostrich,  although 
they  reach  the  sternum.  In  the  Toucans  they  are 
separate,  and  do  not  reach  the  sternum.  In  the 
Hornbills  and  Screech  Owl  (Strix  ulula)  they 
are  united  at  their  inferior  extremities  by  carti- 
lage. In  the  rest  of  the  class  they  are  anchylosed 
together  inferiorly,  and  so  constitute  one  bone, 
thefurculum,  or  merrythought.  From  the  point 
of  union  a  compressed  process  extends  down- 
wards in  the  Diurnal  Raptores,  the  Coniros- 
tral  Insessores,  the  Rasores,  most  of  the  Gral- 
latores,  and  Natatores,  in  which  a  ligament 
extends  from  its  extremity  to  the  ento-sternum. 
The  process  itself  reaches  the  sternum,  and  is  an- 
chylosed therewith  in  the  Pelicans,  Cormorants, 
Grebes,  Petrels,  and  Tropic-bird ;  also  in  the 
Gigantic  Crane,  and  Storks  in  general.  In 
the  Humming-birds,  where  the  sternum  is  so 
disproportionately  developed,  the  furculum  ter- 
minates almost  opposite  the  commencement  of 
the  keel,  but  at  some  distance  before  it;  in 

*  Mr.  Vigors  has  noticed  the  absence  of  the  os 
furcatorium  in  Psittacus  mitratus,  Platycercus  eximius, 
and  Psittucula  Galgula. 


those  species  in  which  we  have  examined  it,  be- 
longing to  the  genus  Trochilus,  Lacrp.  it  is  of 
equal  length  with  the  coracoideum,  and  not 
shorter,  as  Meckel  asserts.  As  the  principal 
use  of  this  elastic  bony  arch  is  to  oppose  the 
forces  which  tend  to  press  the  humeri  inwards 
towards  the  mesial  plane,  during  the  downward 
stroke  of  the  wing,  and  restore  them  to  their 
former  position,  the  clavicles  composing  it  are 
stronger,  and  the  angle  of  their  union  is 
more  open,  as  the  powers  of  flight  are  enjoyed 
in  greater  perfection;  of  this  adjustment  the 
Swifts,  Goat-suckers,  and  Diurnal  Birds  of 
Prey  afford  the  best  examples. 

Notwithstanding  the  anterior  extremity  is 
limited  to  one  function,  and  the  motions  of  its 
parts  are  confined  to  simple  folding  and  exten- 
sion, it  contains  the  same  number  of  joints  as 
the  arm  of  the  Monkey,  or  of  Man  himself.  We 
shall  now  successively  consider  the  bones  of  the 
Brachium,  Antibrachium,  Carpus,  Metacarpus, 
and  Digits. 

The  brachium,  or  humerus  (w,  Jig.  125, 
m,  fg.  130)  is  principally  characterized  by 
the  forms  of  its  extremities.  The  head,  or 
proximal  extremity,  is  transversely  oblong  to 
play  in  the  articular  cavity  formed  by  the  union 
of  the  scapula  and  coracoid  bone.  It  is  further 
enlarged  by  two  lateral  crests:  of  these  the 
superior,  or  external,  which  is  angular,  with  the 
thin  margin  turned  forward,  affords  an  adequate 
attachment  to  the  great  pectoral  muscle:  the 
opposite  process  has  its  margin  rounded  and 
curved  backwards,  and  it  is  beneath  the  arch 
thus  formed  that  the  orifices  are  situated,  by 
which  the  air  penetrates  to  the  cavity  of  the 
bone.  There  is  always  a  deep  depression  at 
this  part,  even  in  birds  which  have  no  air  in 
the  humerus,  as  in  the  Penguins  and  Ostrich. 
The  distal  end  of  the  humerus  is  not  less  cha- 
racteristic of  the  bird,  and  different  from  that 
of  other  vertebrate  animals.  The  articular  hinge 
is  divided  into  two  parts,  one  internal,  which  is 
the  largest,  for  the  ulna,  of  an  almost  spherical 
form,  and  one  external,  for  the  radius,  of  an 
elongated  figure,  extending  for  some  distance 
along  the  anterior  surface  of  the  humerus. 
The  radius  is  thus  made  to  describe  in  the  act 
of  bending  a  greater  portion  of  a  circle  than 
the  ulna,  and  the  whole  fore-arm  moves  in  a 
plane  which  is  not  perpendicular  to  the  anterior 
surface  of  the  humerus. 

The  humerus  is  not  always  developed  in 
length  in  proportion  to  the  powers  of  flight; 
for  although  it  is  shortest  in  the  Struthious 
Birds  and  Penguins,  it  is  also  very  short  in  the 
Swifts  and  Humming-birds.  In  the  latter,  how- 
ever, it  is  characterized  by  its  thickness  and 
strength,  the  size  of  its  muscular  processes, 
and  the  consequent  transverse  extension  of  its 
extremities ;  while  in  the  Cursores  it  is  as 
attenuated  as  it  is  short,  and  in  the  Penguins 
is  reduced  to  a  mere  lamina  of  bone  resembling 
the  corresponding  part  in  the  paddle  of  the 
turtle.  In  the  Rasores  it  rarely  equals  half 
the  length  of  the  body  ;  in  most  other  birds  it 
is  about  two-thirds  that  length;  it  attains  its 
greatest  length  in  the  Albatross.  In  this  and 
other  sea-birds,  as  the  Gulls,  Awks,  and  Petrels, 


286 


AVES. 


the  humerus  presents  a  notable  process  at  the 
outer  side,  near  its  lower  extremity;  and  in 
the  Puffin  ( Fratercula  arctica)  an  ossiculum 
is  moveably  articulated  to  this  process. 

Another  ossiculum  may  here  be  noticed,  al- 
though it  belongs  rather  to  the  ulna,  being 
essentially  the  separated  olecranon  of  that  bone. 
This  detached  sesamoid  bone  is  found  attached 
(like  the  patella  of  the  knee-joint)  to  the  capsular 
ligament  and  the  tendons  of  the  extensor  mus- 
cles, in  many  of  the  Raptores,  and  in  the  Swifts. 
In  the  Penguins  it  is  double  (n,  n,  fig.  130.) 

Of  the  two  bones  of  the  antibrachium 
(y>  fig'  125)  the  ulnar  (o,  fig.  130)  is  always 
the  strongest,  and  especially  so  in  the  Stru- 
thiones:  both  this  and  the  radius  (p,fig.  130) 
are  in  general  slender  and  straight  bones, 
slightly  enlarged  at  their  extremities,  placed 
not  by  the  side  of,  but  one  in  front  of  the  other, 
and  so  articulated  together,  and  with  the  hu- 
merus, as  to  admit  of  scarcely  any  degree  of 
pronation  or  supination,  which,  as  Meckel 
justly  remarks,  adds  to  that  firmness  and  resist- 
ing power  in  the  anterior  member  which  are 
so  necessary  during  the  actions  of  flight.  In 
the  Penguins,  the  bones  of  the  fore-arm  present 
the  same  modifications  as  the  humerus  in  re- 
lation to  the  corresponding  action  in  the  denser 
element,  or  that  of  swimming :  they  are  flat- 
tened, and  are  articulated  with  the  anterior 
edge,  and  not  the  extremity  of  the  humerus. 

The  bones  of  the  hand  are  extended  in 
length,  but  restricted  in  lateral  development. 
The  carpus  consists  of  two  bones  only,  (q,  fig. 
130,)  so  wedged  in  between  the  antibrachium 
and  metacarpus,  as  to  limit  the  motions  of  the 
hand  to  those  of  abduction  and  adduction 
necessary  for  the  folding  up  and  expansion  of 
the  wing ;  the  hand  is  thus  fixed  in  a  state  of 


Fig.  131. 


Pelvis  and  bones  of  the  leg  of  the  Diver,  or  Loon,— Colymbus  glacialis, 


pronation  ;  all  power  of  flexion,  extension,  or  of 
rotation,  is  removed  from  the  wrist-joint,  so  that 
the  wing  strikes  firmly,  and  with  the  full  force  of 
the  contraction  of  the  depressor  muscles,  upon 
the  resisting  air. 

The  metacarpus  is  principally  formed  of  two 
bones,  anchylosed  together  at  both  extremities 
(r,  r,  Jig.  \  30)  ;  of  these,  the  one  which  cor- 
responds to  the  radius  is  always  the  largest, 
and  supports  the  finger  which  has  the  greatest 
number  of  phalanges :  a  third  small  rudi- 
mental  bone  is  in  most  birds  found  an- 
chylosed to  the  outer-side  of  its  proximal 
extremity,  and  this  supports  the  single  phalanx 
of  what  is  usually  called  the  thumb.  The 
longest  or  radial  finger  is  generally  composed 
of  two  phalanges  (s,  s,  Jig.  1 30)  of  moderate 
length  ;  to  which,  in  some  birds,  a  third  smaller 
phalanx  is  added.  The  ulnar  finger  consists  of 
a  single  phalanx  only  (t,fg.  130).  These  are 
strongly  bound  together  by  ligaments  and  in- 
tegument, so  that  the  wing  loses  nothing  of  its 
force,  while  it  preserves  in  these  separated 
bones  its  analogy  with  the  anterior  extremities 
in-  the  other  vertebrated  classes.  In  Zoology 
the  large  feathers  that  are  attached  to  the  ulnar 
side  of  the  hand,  are  termed  Primarne  or  pri- 
mary feathers ;  those  which  are  attached  to  the 
fore-arm  Secundaria,  or  secundaries,  and  Tec- 
trices,  or  wing-coverts ;  those  which  lie  over 
the  humerus  are  called  Scapularia,  or  scapu- 
laries ;  and  those  which  are  attached  to  the 
thumb,  Spurue,  or  bastard  feathers.  In  some 
birds  the  wing  is  armed  with  a  spur  attached 
to  a  phalanx  at  the  radial  side  of  the  so-called 
thumb,  which,  as  Nitzsch  observes,  would 
therefore  seem  analogous  to  the  index  finger. 

The  bones  of  the  leg  or  posterior  extremity 
(Jig.  131J  do  not  exactly  correspond,  in  their 
divisions  or  principal 
groups,  to  those  of  the 
wing,  the  segment  corre- 
sponding to  the  carpus 
being  invariably  blended 
with  the  one  that  suc- 
ceeds. 

The  pelvic  bones  present 
a  remarkable  contrast  to 
those  of  the  shoulder, 
being  always  anchylosed 
on  either  side  into  one 
piece,  but  being  with 
one  exception  \  never 
joined  in  the  mesial  line, 
while  this  is  the  only  place 
where  the  elements  of  the 
scapular  apparatus  are  in 
general  united  by  bone. 
In  the  young  bird  the 
os  innominatum  is  seen 
to  be  formed  by  the  usual 
three  bones,  viz.  the  ilium, 
ischium,  and  pubis,  corre- 
sponding respectively  to 
the  scapula,  coracoid,  and 
clavicle,  of  the  anterior 
extremity. 

The  ilium  ($,fig.  125, 
a,  fig.  131.)  is  the  only 


AVES. 


287 


bone  of  the  pelvis  which  comes  in  con- 
tact with  the  vertebral  column,  and  it  ex- 
tends from  the  posterior  dorsal  vertebrae  along 
the  whole  of  the  sacrum,  to  which  it  is  early 
united  by  anchylosis.  At  its  posterior  extre- 
mity it  is  expanded  laterally  and  becomes 
anchylosed  with  the  ischium  (c,fig.  131)  pos- 
terior to  the  ischiadic  notch  (e,Jig- 131)  which 
is  thus  converted  into  a  foramen. 

The  ilium  is  of  a  considerable  size,  of  an 
elongated  form,  expanded  at  its  extremities  and 
contracted  in  the  middle  ;  the  anterior  expan- 
sion is  concave  externally,  the  posterior  on  the 
contrary  convex.  Besides  being  anchylosed 
with  the  ischium  and  sacrum,  the  spinous  and 
transverse  processes  of  one  or  two  posterior 
dorsal  vertebrae  are  commonly  joined  to  it  by 
bony  union.  In  the  Penguins,  however,  where 
the  posterior  extremities  are  ill  adapted  for 
su pporting  the  body  in  progressive  motion 
on  land,  the  ilium  appears  at  no  time  to  be 
anchylosed  with  any  part  of  the  vertebral  co- 
lumn. 

The  os  pnbis  (^  fig.  125,  b  b,  Jig.  131 )  does 
not  extend  to  meet  its  fellow  on  the  mesial 
line,  but  is  commonly  directed  backwards  like 
a  long  bent  styliform  process  (3,  Jig.  134), 
adapted  to  allow  a  safe  passage  to  the  large 
and  fragile  eggs.  In  general  it  unites  with  the 
ischium  so  as  to  complete  the  obturator  fora- 
men (J\  fig.  131),  behind  which  another  fo- 
ramen is  occasionally  formed  by  a  second 
union  with  the  ischium,  as  is  seen  in  the  Hum- 
ming-bird ;  while  in  other  Birds,  as  the  Stork, 
it  is  only  united  to  the  ischium  at  the  cotyloid 
foramen,  and  the  obturator  hole  communicates 
with  a  long  fissure  and  is  completed  posteri- 
orly by  ligament  only.  The  cotyloid  cavity  for 
the  head  of  the  thigh-bone  is  always  incomplete 
at  its  posterior  or  internal  part,  which  is  closed 
in  the  recent  state  by  a  strong  aponeurosis. 

The  ischium  (c,  jig.  131)  is  a  small  elon- 
gated bone,  slightly  convex  externally,  ex- 
tending from  the  acetabulum  backwards,  pa- 
rallel with  the  ilium. 

In  the  Struthious  Birds  the  pelvis  is  pro- 
portionally very  long,  but  narrow  ;  the  ossa 
innominata  cover  the  whole  of  the  sacrum, 
meeting  and  joining  above  that  part  like  the 
roof  of  a  dwelling.  In  the  Rhea,  or  Ame- 
rican Ostrich,  the  ischiadic  bones  meet  below 
the  sacrum,  where  they  are  united  for  a  con- 
siderable extent  by  a  symphysis,  so  that  the 
sacrum  is  closely  surrounded,  and  in  fact  its 
place  is  almost  supplied  by  the  ossa  inno- 
minata, for  the  development  of  the  included 
vertebrae  is  in  consequence  so  much  impeded, 
that  they  can  scarcely  be  detected  at  this 
part;  beyond  which,  however,  the  coccygeal 
vertebrae  suddenly  resume  their  ordinary  mag- 
nitude. This  union  of  the  ischia  does  not 
take  place  in  the  other  Struthious  birds ;  but 
the  Ostrich  presents  the  remarkable  exception, 
among  Birds,  of  the  completion  of  the  pelvic 
circle  by  the  anchyloses  of  the  pubic  bones  at 
their  inferior  extremities. 

The  femur  (Q,frg.  125,  g,fig.  131)  is  a  short 
cylindrical  bone,  deviating  from  the  straight  line 


by  a  very  slight  anterior  convexity.  The  head 
is  a  small  hemisphere;  joined,  without  the  in- 
tervention of  a  neck,  at  a  right  angle,  to  the 
shaft  of  the  bone  :  it  presents  at  its  upper  part, 
a  considerable  depression  for  the  attachment  of 
the  round  ligament.  The  single  large  trochan- 
ter  generally  rises  above  the  articular  eminence, 
and  is  continuous  with  the  outer  side  of  the 
shaft.  The  orifice  for  the  admission  of  air 
into  the  bone  is  situated  anterior  to  this  ca- 
vity. The  femur  is  most  readily  characterised 
by  the  form  of  its  lower  extremity :  this  pre- 
sents as  usual  two  condyles,  the  inner  one  cor- 
responding to  the  tibia,  the  outer  one,  which 
is  the  largest  and  the  longest,  resting  both  upon 
the  tibia  and  fibula;  upon  this  condyle  a  semi- 
circular rounded  eminence  is  observed  extend- 
ing from  the  front  to  the  back  part,  and  being 
lost  in  a  depression  at  both  extremities;  the 
result  of  this  structure  is  to  put  the  external 
lateral  ligament  upon  the  stretch  when  the 
fibula  is  passing  over  the  middle  of  the  condyle, 
and  that  ligament,  being  elastic,  pulls  the 
fibula  into  the  cavity  in  which  the  ridge  termi- 
nates, with  a  jerk — whether  the  motion  be  that 
of  flexion  or  extension,  in  either  of  which  con- 
ditions the  leg  is  by  this  structure  the  more 
firmly  locked  to  the  thigh.  It  has  been  denied 
that  the  spring-joint  ever  exists  at  the  knee,  and 
it  is  probable  that  all  birds  do  not  possess  the 
requisite  structure  in  the  same  perfection  ;  but 
a  common  indigenous  species,  the  Water-hen, 
(Gullinula  Chloropus)  affords  a  good  example 
of  the  beautiful  mechanism  in  question.  The 
femur  attains  its  greatest  development  in  the 
Ostrich ;  but  in  this  species  it  is  short  in  com- 
parison to  the  other  bones  of  the  leg,  the  length 
of  which  in  the  Stilt-bird  and  other  Waders  is 
attained  solely  by  the  elongation  of  the  tibia 
and  metatarsus. 

The  tibia  (»J%.125,M,./Zg.l31)  is  the  prin- 
cipal bone  of  the  leg — thejibula  (x,Jig-  125,  «', 
Jig.  131)  appearing  as  a  mere  styliform  process 
tapering  to  a  point  below,  and  anchylosed  for  a 
greater  or  less  extent  to  the  tibia.  The  tibia  is 
of  a  triangular  form,  especially  at  its  enlarged 
superior  extremity,  the  articular  surface  of  which 
is  unequal,  being  flat  internally,  convex  at  the 
centre,  and  concave  externally  and  in  front. 
The  inferior  articular  surface  of  the  tibia  forms 
a  considerable  transverse  trochlea,  above  which 
anteriorly  there  is  a  deep  depression.  In  ge- 
neral an  osseous  bridge  extends  transversely 
across  this  depression,  converting  it  into  a 
foramen  through  which  the  tendon  of  the  Exten- 
sor communis  digitorum  passes. 

In  the  Divers,  Grebes,  Guillemots,  and 
Albatrosses  the  middle  and  internal  crests  of  the 
tibia  unite  superiorly  and  are  extended  up- 
wards into  a  long  pointed  process  (k,  Jig.  131) 
directed  inwards  and  forwards,  anterior  to,  but 
not  supplying  the  place  of,  the  patella,  (I,  Jig. 
131)  which  will  be  always  found  as  a  distinct 
bone  behind  this  process.  The  process  is  most 
developed  in  the  genus  Colymbus,  and  affords 
extensive  attachments  by  way  of  insertion  to 
the  extensors  of  the  tibia,  and  by  way  of  origin 
to  the  extensors  of  the  metatarsus ;  by  means 


288 


AVES. 


of  the  latter  disposition  the  power  of  the  back 
stroke  of  the  foot  is  increased. 

The  Tarsus  can  only  be  recognized  as  a 
distinct  segment  of  the  leg  when  the  bones 
of  a  very  young  Bird  are  examined.  But 
in  the  Ostrich,  even  when  it  has  attained 
a  third  of  its  natural  size,  the  Astragalus  re- 
mains ununited  to  the  metatarsus.  It  is  a 
flattened  transversely  oval  bone,  convex  in  the 
middle  of  its  upper  surface,  and  irregularly 
flattened  below,  where  it  is  adapted  to  the 
three  still  partially  separated  bones  of  the 
metatarsus.  A  rudiment  of  the  os  calcis  may 
be  observed  in  the  detached  bone  which  is 
found  in  the  tendons  of  the  extensors  of  the 
foot  near  their  insertion.  The  Capercailzie 
( Tetrao  urogallus)  affords  a  good  example  of 
this  structure.  The  process  (m,  Jig.  131)  in 
which  the  above  tendons  are  inserted,  and 
which  is  very  prominent  in  the  Hasores,  Gral- 
latores,  and  Natatores,  must  also  be  regarded 
as  appertaining  to  the  tarsal  series,  since  it  com- 
mences by  a  separate  ossification. 

In  most  birds,  however,  the  tendo  Achillis 
has  no  sesamoid  bone  to  add  to  its  leverage,  and 
in  all  birds  the  astragalus  is  soon  anchylosed  to 
the  metatarsus,  constituting  with  it  one  elongated 
tarso-metatarsal  bone  (A,  fg.  125,  n,  Jig.  131). 
Traces  of  the  number  of  laterally  anchylosed 
pieces  of  which  the  metatarsus  is  composed 
are  always  more  or  less  indicated  by  longitu- 
dinal grooves.  In  the  Penguins,  indeed,  the 
anchylosis  of  the  three  metatarsal  bones  takes 
place  at  their  extremities  only,  and  they  are 
consequently  separated  from  each  other  in  the 
greater  part  of  their  extent.  They  are  also 
disproportionately  short,  and  bent  forwards 
upon  the  tibia,  so  as  to  increase  the  surface  of 
support  required  by  these  birds  when  standing 
in  their  usually  erect  position.  In  the  Gralla- 
tores  and  Struthiones,  on  the  contrary,  the 
tarso-metatarsal  bone  is  remarkably  elongated, 
the  extraordinary  length  of  leg  in  these  birds 
depending  chiefly  upon  the  extent  of  this  seg- 
ment of  the  limb. 

In  the  Stork  and  congeneric  birds,  which 
sleep^on  one  leg,  the  ankle-joint  presents  a 
mechanism  analogous  to  that  which  we  have 
above  described  in  the  knee-joint.  Here,  how- 
ever, the  projection  which  causes  the  extension 
of  the  elastic  ligaments  in  the  motion  of  the 
joint  is  in  the  inferior  bone.  Dr.  Macartney 
thus  describes  the  mechanism  :  "  There  arises, 
from  the  fore-part  of  the  head  of  the  metatarsal 
bone,  a  round  eminence,  which  passes  up  be- 
tween the  projections  of  the  pulley  on  the  an- 
terior part  of  the  end  of  the  tibia.  This  emi- 
nence affords  a  sufficient  degree  of  resistance 
to  the  flexion  of  the  leg  to  counteract  the  effect 
of  the  oscillations  of  the  body,  and  would 
prove  an  insurmountable  obstruction  to  the 
motion  of  the  joint,  if  there  were  not  a  socket 
within  the  upper  part  of  the  pulley  of  the 
tibia  to  receive  it  when  the  leg  is  in  a  bent 
position.  The  lower  edge  of  the  socket  is 
prominent  and  sharp,  and  presents  a  sort  of 
barrier  to  the  admission  of  the  eminence  that 
requires  a  voluntary  muscular  exertion  of  the 


bird  to  overcome,  which  being  accomplished 
it  slips  in  with  some  force  like  the  end  of  a 
dislocated  bone."*  It  must  be  added,  that  the 
elastic  lateral  ligaments  contribute  also  to  jerk 
the  metatarsal  tubercle  into  the  tibial  cavities, 
and  to  resist  its  displacement. 

The  lower  extremity  of  the  metatarsus  is 
divided  into  three  articular  eminences,  corres- 
ponding to  the  ordinary  number  of  anterior 
toes.  These  eminences  are  convex  from  before 
backwards,  and  the  middle  one,  which  is  the 
longest,  is  converted  into  a  pulley  by  a  mesial 
groove  which  traverses  it  in  the  same  direction. 
The  lateral  surfaces  are  simply  convex,  and 
very  narrow  ;  of  these  the  internal  is  the  short- 
est, except  in  the  raptorial  birds.  At  the  extre- 
mities of  the  grooves  which  indicate  the  lateral 
juxtaposition  of  the  metatarsal  pieces,  there  are 
ordinarily  foramina  extending  from  before  back- 
wards through  the  bone. 

A  fourth  articular  surface  is  observable  in 
most  birds  on  the  inner  and  posterior  side  of 
the  metatarsal  bone;  this  is  situated  on  an  ac- 
cessory piece  which  always  commences  by  a 
separate  ossification,  although  in  some  birds  it 
afterwards  becomes  anchylosed  with  the  inner- 
most of  the  other  juxtaposed  components  of 
the  metatarsus.  When  this  does  not  take  place, 
the  metatarsus  presents  a  rough,  more  or  less 
irregular,  oval  surface,  for  the  firm  ligamentous 
attachment  of  the  accessory  bone  which  sup- 
ports the  back  toe,  usually  termed  the  hallux  or 
posterior  thumb.  This  articulating  surface  is 
important  as  affording  a  good  distinctive  cha- 
racter for  identifying  the  bones  of  birds  in  a 
fossil  state,  and  the  more  so  as  its  position  is 
indicative  of  the  powers  of  grasping  or  perching 
— being  placed  low  down,  on  a  level  with  the 
anterior  toes,  in  those  birds  which  enjoy  the 
insessorial  power  in  the  greatest  perfection,  and 
being  gradually  removed  higher  and  higher  in 
the  Waders,  until  it  is  at  length  wholly  lost,  as 
in  the  genus  Cursorius,  the  Bustards,  and  the 
Struthious  family.  In  the  Petrel,  however, 
this  accessory  metatarsal  bone  is  wanting,  al- 
though the  hallux  is  present,  the  two  bones  of 
which  are  therefore  united  to  the  principal  me- 
tatarsal bone  by  long  ligaments.  The  tarso- 
metatarsal  bone  is  further  characterized  by 
sharp  longitudinal  ridges  of  bone  on  the  pos- 
terior surface,  which  afford  attachment  to  the 
aponeurotic  thecae  confining  the  tendons  which 
glide  along  the  metatarsus  to  the  toes. 

In  birds,  as  in  mammalia,  the  number  of 
toes  is  subject  to  great  variety;  if  the  spur  of 
the  Gallinaceous  tribe  be  regarded  as  one,  we 
may  then  reckon  the  ordinary  number  of  five 
in  these  birds,  while  in  the  Ostrich  the  toes  are 
reduced  to  two.  Birds  are,  however,  the  only 
class  of  animals  in  which  the  toes,  whatever  be 
their  number  or  relative  size,  always  differ  in 
the  number  of  their  phalanges,  yet  at  the  same 
time  preserve  a  constancy  in  that  variation. 

The  following  is  a  tabular  view  of  the  nume- 
rical relation  in  the  osseous  parts  of  the  feet  of 

*  See  Transactions  of  the  Royal  Irish  Academy, 
vol.  xiii.  p.  20. 


AVES. 


289 


birds  according  to  the  researches  of  Cuvier, 
the  discoverer  of  this  remarkable  peculiarity  in 
the  anatomy  of  birds. 

Table  of  the  number  of  toe  phalanges  in 

Jiirds. 
Number  of  Phalanges  in  the 


First  or 
inner- 
most 
toe  or 
Calcar. 

Second, 
com- 
monly 
called 
the 
Hnllux. 

Third. 

Fourth. 

Fifth'or 
outer- 
nost,or 
little 
toe. 

1  Cock    (Gal- 

lus),    Phea- 

sants (  P/ia- 

sianus),  Tur- 

keys,     Pea- 

cocks (  Pavo 

and     Lopho- 

pliorus)     .    . 

1* 

2 

3 

4 

5 

2  Raptores,Tn- 

sessores,    Co- 

lumbidce,  Cra- 

cidce,  Tetrao- 

7u'da?,and  the 

rrst    of    the 

class,  except 

it 

3* 

m 

5|| 

3  The  Genera, 

Rhea,    Dra- 

in* ii  us,  Casu- 

al-ins,     Otis 

Cursoriitx, 

Cfuiradrius, 

Hevmatopus, 

Arenaria, 

Falcinella, 

ffimatttopvt, 

Halodroma, 

Diomedea     . 

3 

4 

5 

4  The  Ostrich 

(Struthio)    . 

4 

5 

The  above  table  shows  what  are  the  toes 
which  are  deficient  in  those  birds  that  do  not 
possess  the  ordinary  number. 

The  phalanges  are  expanded  at  their  extre- 
mities, especially  at  the  posterior  ;  the  articular 
surfaces  are  concave  at  this  end,  but  divided 
longitudinally  by  a  narrow  convex  line,  to  which 
a  corresponding  unequal  surface  at  the  anterior 

*  This  is  wanting  in  the  Argus  Pheasant ;  the 
Pavo  bicalcaratus,  on  the  contrary,  has  two  spurs 
on  each  metatarsal  bone. 

t  In  the  single  genus  Ceyx  among  the  Insessores, 
and  Hemipodius  among  the  Rasores,  this  toe  is 
wanting.  In  all  the  rest,  with  the  exception  of 
the  Swifts  (Cypselus)  it  is  directed  backwards. 

\  In  the  Dentirostral  Insessores  this  toe  is  united 
by  one  or  two  phalanges  to  the  fourth. 

$  According  to  Cuvier  this  toe  and  the  fifth  in 
the  Swift  (  Cypselus)  have  only  three  phalanges  like 
the  third.  In  the  Goat-suckers  ( Cuprimulyus)  and 
Herons  (Ardea)  the  claw  of  this  toe  is  provided 
with  dentations  similar  to  a  comb  on  its  inner  side. 

||  This  toe  is  stated  by  Cuvier  to  have  only  four 
phalanges  in  the  Goat-suckers,  and  we  have  ascer- 
tained the  correctness  of  the  exception,  and  that 
it  also  obtains  in  the  Rhea.  This  toe  is  united 
to  the  fourth  toe  as  far  as  the  penultimate  joint 
in  the  Bee-eaters  (Merops),  the  Motmots  ( Prio- 
mtes),  the  King-fishers  (Aleedo),  the  Todies 
(  Todus),  and  the  Hornbills  (  Buceros ),  which  form 
in  consequence  the  family  Syiuhtctyli  of  Cuvier. 
In  the  S  ansores  this  toe  is  turned  backwards, 
and  assists  the  Hallux  in  opposing  the  other  toes. 
The  Owls  have  the  j.ower  of  turning  back  the 
outer  toe  at  pleasure. 
VOL.  i. 


end  of  the  preceding  phalanx  is  adapted,  con- 
stituting a  ginglymoid  articulation.  The  ulti- 
mate or  ungueal  phalanges  are  characterised  by 
their  anterior  pointed  terminations,  which  cor- 
respond in  form,  in  some  degree,  to  the  nature 
of  the  claw. 

132. 


Foot  of  the  Goat-sucker. 


Of  the  fossil  bones  of  birds. — Birds  differ 
from  each  other  in  a  much  less  degree  than  qua- 
drupeds, less,  perhaps,  than  any  other  class. 
The  Penguin  and  the  Ostrich  have,  indeed, 
but  a  remote  external  resemblance  with  the 
Eagle  or  the  Swallow,  but  yet  they  have  never 
been  regarded  as  other  than  birds.  The  Por- 
pesse  and  the  Whale,  on  the  other  hand,  al- 
though their  real  affinities  were  pointed  out 
by  Aristotle,  have  been  placed  by  many  sub- 
sequent Zoologists  in  a  very  different  class 
from  the  Lion  or  the  Ape,  and  in  the  older 
systems  of  Natural  History  they  always  ob- 
tained their  position  among  the  true  fishes. 

Osteological  characters  of  the  same  value 
with  those  which  serve  to  distinguish  the 
genera,  and  for  the  most  part  the  species  of 
Mammalia,  are,  therefore,  with  difficulty  found 
in  the  Class  of  Birds.  Cuvier  has  declared 
that  the  differences  in  the  skeleton  of  two 
species  of  an  ornithological  genus  are  some- 
times wholly  inappreciable,  and  that  the  oste- 
ological  characters  of  Genera  can  rarely  be 
detected  in  any  other  part  than  in  the  bones 
of  the  mandibles,  which,  do  not  always  con- 
form in  a  sufficiently  characteristic  manner 
with  the  modifications  of  the  horny  bill. 

The  determination  of  the  fossil  bones  of  this 
class  is,  therefore,  conjectural,  or,  at  least,  it 
wants  much  of  that  demonstrative  character 
which  the  bones  of  quadrupeds  afford. 

The  fossil  bones  of  birds  described  by  Cu- 
vier are  considered  by  him  to  appertain  to  a 
species  of  Buzzard,  Owl,  Quail,  Woodcock, 
Ibis,  Sea-lark,  and  Cormorant;  and,  although 
not  remarkable  for  their  number  or  for  their 
zoological  interest,  yet  they  demonstrate  that 
the  species  which  existed  at  that  remote  period, 
when  the  Anoplotheriums  and  other  extinct 
quadrupeds  trod  the  face  of  the  earth,  had  the 
same  proportion  of  parts,  the  same  length  of 
wings  and  legs,  the  same  articulations  of  the 
toes,  the  same  form  and  numerical  proportions 
of  the  vertebra;  in  short,  that  their  whole 
organization  was  regulated  by  the  same  general 

u 


290 


AVES. 


laws  of  co-existence  and  all  that  relates  to  the 
nature  of  the  organs  and  their  essential  func- 
tions, as  at  the  present  day.  They  afford  no 
evidence,  not  even  a  trace  of  any  part  having 
been  lengthened  or  curtailed,  or  otherwise  pro- 
gressively modified,  either  by  the  operation  of 
external  causes  or  by  internal  voluntary  im- 
pulse. 

Myology. — The  muscular  system  of  Birds 
is  remarkable  for  the  distinctness  and  density 
of  the  carneous  fibres,  their  deep  red  colour, 
and  their  marked  separation  from  the  ten- 
dons, which  are  of  a  brilliant  shining  colour, 
and  have  a  peculiar  tendency  to  ossification. 
This  high  degree  of  development  results  from 
the  rapid  circulation  of  very  warm  blood, 
which  is  highly  oxygenated  in  consequence  of 
the  activity  and  extent  of  the  respiratory  func- 
tion. The  energy  of  the  muscular  contraction 
in  this  class  is  in  the  ratio  of  the  activity  of 
the  vital  functions,  but  its  permanent  irrita- 
bility is  proportionally  low,  as  Carus  has  justly 
observed. 

Fig.  133. 


Muscles  of  a 

These  characteristic  properties  are  mani- 
fested in  the  greatest  degree  in  the  muscles 
of  those  families  of  the  Insessores  which  take 


their  food  on  the  wing,  as  the  Hirundinida  and 
Trochilida  (Swallows  and  Humming-birds) ; 
in  the  Diurnal  Raptores  and  in  the  long- 
winged  Palmipedes,  as  the  Albatross,  Tropic 
Bird,  &c.  In  the  more  heavy  and  slow- 
moving  Herbivorous  families,  and  in  the  short- 
winged  Swimmers,  as  the  Penguins,  &c.  the 
muscles  resemble  those  of  the  Reptilia  in  their 
softness  and  pale-colour. 

The  mechanical  disposition  of  the  muscular 
system  is  admirably  adapted  to  the  aerial  loco- 
motion of  this  class;  the  principal  masses 
being  collected  below  the  centre  of  gravity, 
beneath  the  stev.ium,  beneath  the  pelvis,  and 
upon  the  thighs,  they  act  like  the  ballast  of  a 
vessel  and  assist  in  maintaining  the  steadiness 
of  the  body  during  flight,  while  at  the  same 
time  the  extremities  require  only  long  and  thin 
tendons  for  the  communication  of  the  muscu- 
lar influence  to  them  and  are  thereby  rendered 
light  and  slender. 

Muscles  of  the  trunk. — The  muscles  of  the 
cervical  region  are  the  most  developed,  as  might 
be  expected  from  the  size  and  mobility  of  this 
part  of  the  spine ;  the  muscles  which  are  situ- 
ated on  the  dorsal  and  lumbar  regions  are,  on 
the  other  hand,  very  indistinct,  feeble,  and  but 
slightly  carneous ;  they  are  not,  however, 
entirely  wanting. 

The  Semi-spinalis  dorsi  or  Opisthotenar,  is 
easily  recognizable,  occupying  the  space  be- 
tween the  spinous  and  transverse  processes, 
arising  from  the  anterior  margin  of  the  ilium 
and  the  transverse  processes  of  the  sacrum, 
and  attached  by  means  of  long  tendons  to  the 
transverse  processes  of  the  costal  vertebrae. 
It  is  most  developed  in  those  birds  which  have 
the  greatest  mobility  in  this  part  of  the  spine, 
as  in  the  Penguins,  in  which  the  external  venter 
of  the  muscle  is  well  developed,  inserted  into 
the  vertebral  ends  of  the  ribs,  and  adapted  to 
support  the  body  in  the  erect  position  which 
these  birds  assume  while  standing. 

On  the  mesial  aspect  of  this  muscle  and 
somewhat  covered  by  it,  the  Spinalis  dorsi  may 
be  distinctly  traced,  passing  from  the  spinous 
processes  behind,  to  those  at  the  anterior  part 
of  the  trunk  and  beginning  of  the  neck. 

The  Cervicalis  ascendens  (1,  Jig.  133)  is  the 
chief  extensor  of  the  neck  :  it  rises  from  the 
spines  of  the  anterior  dorsal  vertebrae,  and  is 
inserted  by  long  and  separate  fasciculi  into  the 
posterior  articular  processes  of  the  second, 
third,  and  fourth  cervical  vertebrae.  In  this 
course  it  receives  descending  slips  of  muscle 
from  the  spines  of  the  inferior  cervical  vertebrae, 
and  ascending  fasciculi,  which  furnish  tendons 
to  the  fifth  and  sixth  vertebrae,  and  to  the  atlas, 
so  that  it  is  enabled  to  extend  the  neck  even 
while  the  head  is  raised. 

Muscles  corresponding  to  the  Intertrans- 
versales  (2)  are  continued  on  the  neck  from 
the  external  belly  of  the  Opisthotenar ;  these 
slips  extend  from  the  articular  processes  of  the 
dorsal  vertebrae  to  those  of  the  inferior  cervical. 
Posterior  to  the  Intertransversales,  the  Semispi- 
nalis  colli  (3)  is  seen  passing  from  the  trans- 
verse to  the  spinous  processes. 
The  Longus  colli  arises  from  the  anterior 


A\ 


spinous  processes  of  the  dorsal  vertebrae  and 
from  the  anterior  part  of  the  cervical  vertebra', 
and  these  slips  diverge  to  be  inserted  into  the 
transverse  processes,  and  their  appended  styles 
or  spurious  ribs. 

A  superadded  muscle,  which  may  be  re- 
garded as  a  continuation  of  the  preceding,  and 
which  corresponds  to  the  increased  number  of 
the  vertebrae  of  the  neck,  passes  from  the 
transverse  processes  of  the  five  superior  ver- 
tebrae to  the  anterior  spines  of  the  vertebrae 
immediately  anterior — a  portion  of  this  muscle 
is  shown  at  5. 

No.  6  indicates  one  of  the  most  remarkable 
muscles  in  the  cervical  region  of  Birds ;  it 
is  analogous  to  the  Biventer  ccrvicis  of  mam- 
mals, but  has  a  much  longer  and  more 
distinct  middle  tendon,  a.  6.  Its  lower  or  pos- 
terior venter,  b.  6,  arises  by  a  tendon,  most  com- 
monly from  the  short  spinous  processes  of  the 
lowest  cervical  vertebrae,  the  anterior  fleshy 
part  c  is  inserted  into  the  squamous  spine  of 
the  occiput.  This  muscle  is  well  developed 
in  the  Ostrich,  where  it  arises  as  low  down  as 
from  the  last  lumbar  vertebra,  by  a  long  ten- 
don, which  is  continued  to  the  cervical  region 
before  it  joins  the  fleshy  portion,  the  whole 
muscle  affording  a  striking  example  of  the 
peculiar  development  of  the  tendinous  over 
the  carneous  part  which  characterizes  the  mus- 
cular system  of  Birds.  In  the  Parrots  and 
Raptorial  birds,  however,  the  carneous  exceeds 
the  tendinous  part  of  this  muscle. 

The  Contplexus  (7)  arises  from  the  articular 
and  transverse  processes  of  a  variable  number 
of  the  superior  cervical  vertebrae,  and  passes 
obliquely  backwards  to  be  inserted  into  the 
occiput,  crossing  exteriorly  the  upper  belly  of 
the  preceding  muscle. 

The  Trachelo-mastoidcm  (8)  arises  from  the 
articular  processes  of  the  cervical  vertebra;  from 
the  second  to  the  sixth,  and  is  inserted  into 
the  posterior  part  of  the  basis  cranii. 

Anterior  to  the  preceding  muscle  a  portion 
of  the  Rectus  capitis  an  tic  us  major  may  be 
seen  at  4.  This  muscle  is  largely  developed, 
arising  from  the  anterior  part  of  the  sixth, 
seventh,  and  eighth  vertebrae,  and  inserted  into 
the  basis  cranii.  There  are  also  muscles  ana- 
logous to  the  Rcctns  capitis  anticus  minor,  the 
Kccti  postici  majores  et  minores,  the  ObLiquus 
cjcternus  or  superior,  and  in  the  Penguin,  a 
strong  tendon  is  given  off  from  the  Trachelo- 
mastoideus  which  represents  the  obliquus  in- 
ferior of  the  neck. 

When  it  is  remembered  that  the  cervical  re- 
gion of  the  spine  in  Birds  is  subservient  and 
essential  to  all  the  movements  and  functions 
of  the  bill,  as  a  prehensile  instrument,  and  a 
cleanser  of  the  plumage,  we  cannot  sufficiently 
admire  the  endowments  of  length,  flexibility, 
and  muscularity,  by  which  it  is  enabled  to 
fulfil  the  important  functions  of  an  additional 
extremity. 

In  the  caudal  region  of  the  spine  the  fol- 
lowing muscles  present  themselves.  On  the 
dorsal  aspect,  the  Levator  cocci/gis  (10)  ex- 
tends from  the  transverse  processes  and  lower 


extremity  of  the  .sacrum  to  the  superior  spines 
of  the  coccyx  and  the  base  of  the  last  or 
plough-share  vertebra.  This  muscle  may  be 
regarded  as  a  continuation  of  the  spinalis  dorsi. 
Beneath  it  are  found  strong  Interspiuules  mus- 
cles. 

The  Quadratus  coccygis  (11)  arises  from  the 
transverse  processes  of  the  coccygeal  vertebras 
and  is  inserted  into  the  shafts  of  the  reclrices 
or  tail-quills,  which  it  separates  and  raises. 
On  the  lateral  aspect  we  find  the  Pubo-coccy- 
geus  (12)  arising  from  the  posterior  margin  of 
the  pubis,  and  inserted  also  into  the  shafts  of 
the  exterior  rectrices;  it  is  by  means  of- these 
muscles  in  conjunction  with  the  two  preceding 
that  the  Peacock  spreads  its  gorgeous  tail. 

The  Ilio-coccygetu  (13)  extends  from  the 
posterior  margin  of  the  ilium  to  the  last  coccy- 
ueal  vertebra,  and  to  the  small  inferior  tail- 
feathers. 

On  the  ventral  or  inferior  aspect  of  the  tail, 
the  muscles  are  in  general  more  feebly  developed 
than  on  the  opposite  side,  except  in  the  Wood- 
peckers, where  the  tail,  by  means  of  its  stiff  and 
pointed  quill-feathers,  serves  as  a  prop  to  sup- 
port the  bird  on  the  perpendicular  trunks  of  trees 
on  which  it  seeks  its  food.  In  these  the  Ischio- 
cocci/geits  (14)  is  of  large  size,  extending  from 
the  lower  edge  of  the  ischiadic  tuberosity,  and 
from  the  transverse  processes  of  the  anterior 
coccygeal  vertebrae  to  the  inferior  spines  of  the 
posterior  coccygeal  vertebrae,  and  to  the  sides 
of  the  last  compressed  or  plough-share  bone. 

The  Depressor  coccygis  (15)  extends  from 
the  ventral  aspect  of  the  bodies  of  the  anterior 
coccygeal  vertebra  to  the  inferior  spines  of  the 
posterior  and  to  the  base  of  the  last  vertebra. 

Of  the  Muscles  of  the  head  those  which  are 
attached  to  it  for  its  general  motions  have 
already  been  described;  the  remaining  mus- 
cles of  this  part  are  devoted  to  the  movements 
of  the  jaws,  the  tongue,  the  eye,  and  the  ear. 
The  cutaneous  muscles  of  the  face  are  usually 
described  as  being  entirely  deficient,  and  the 
only  ones  that  can  be  regarded  as  belonging 
to  this  series  are  the  slips  of  panniculus  car- 
nosus,  analogous  to  an  occipito-fronta/is  (16), 
which  are  chiefly  developed  in  order  to  elevate 
the  crest-feathers  in  those  birds  which  possess 
that  ornament ;  there  are  also  cutaneous  slips 
which  belong  more  properly  to  the  organs  of 
hearing,  and  which  raise  the  auricular  circle  of 
feathers  in  the  Owls,  Bustards,  &c. 

The  muscles  of  the  jaws  are  chiefly  mo- 
dified in  relation  to  the  moveable  condition 
of  the  upper  mandible  and  tympanic  bone, 
and  the  subserviency  of  the  latter  to  the  actions 
of  these  parts. 

The  Temporalis  (17)  fills  the  temporal  fossa, 
which  consequently  indicates  the  bulk  of  that 
muscle  in  the  dry  skull.  It  arises  from  a 
greater  or  less  extent  of  the  temporal  and 
parietal  bones,  and,  as  it  passes  within  the 
zygoma,  becomes  closely  blended  with  the 
Musseter;  the  united  muscles  derive  an  acces- 
sion of  fibres  from  the  lower  part  of  the 
orbit,  and  are  inserted  into  the  raised  superior 
margin,  representing  the  coronoid  process ; 

u  2 


292 


AVES. 


and  into  the  sides  of  the  lower  jaw  from  the 
articulation  as  far  forward  as  the  commence- 
ment of  the  horny  bill. 

In  the  Cormorant  there  projects  backwards 
from  the  spine  or  squamous  element  of  the 
occipital  bone,  an  osseous  style  about  an  inch 
in  length,  of  a  trihedral  figure  and  tapering  to 
a  point.  It  is  not  anchylosed  as  a  process  of 
the  occiput,  but  is  moveably  articulated  to  it ; 
and  its  description  has  been  referred  to  this 
section  because  it  does  not  constitute  a  regular 
part  of  the  skeleton,  not  representing  any 
essential  element  of  the  bony  fabric,  but  is  to 
be  regarded  like  the  bony  tendons  of  the  legs 
as  an  ossification  of  the  intermuscular  aponeu- 
rosis  of  the  temporal  muscles  to  which  it 
affords  a  more  extensive  and  firmer  origin. 
This,  indeed,  is  its  essential  use,*  for  the  mus- 
cles of  the  upper  part  of  the  neck  are  inserted 
into  the  occipital  bone,  and  glide  beneath  the 
posterior  or  superadded  fasciculi  of  the  tem- 
poral muscle.  Analogous  parts  appended  to 
the  true  spinous  processes  of  the  vertebrae  are 
met  with  abundantly  in  the  inferior  vertebrate 
classes,  especially  in  fishes,  where  they  extend 
frequently  above  the  spines  of  the  whole  ver- 
tebral column,  increasing  the  surface  of  origin 
of  the  lateral  series  of  muscles. 

The  muscle  analogous  to  the  Biventer 
maxilla:  (18)  arises  by  two  portions,  the  one 
from  the  lateral  depression  of  the  occiput,  the 
other  from  the  depression  behind  and  below 
the  external  meatus  auditorius ;  they  are  in- 
serted into  the  back  part  and  angle  of 
the  lower  jaw.  A  similar  disposition  of 
the  dignstricus  is  met  with  in  many  of  the 
mammalia;  even  in  the  Orang-utan  (Simla 
Satyrus)  it  is  equally  devoid  of  a  central 
tendon,  and  is  unconnected  with  the  os  hyoides. 

The  openers  and  closers  of  the  mandibles 
present  very  slight  differences  of  bulk  in  rela- 
tion to  the  development  of  the  parts  they  are 
destined  to  move;  their  disproportion  to  the 
bill  is,  on  the  contrary,  truly  remarkable  in  the 
Horn-bills,  Toucans,  and  Pelican,  and  the  bill 
is  but  weakly  closed  in  these  in  comparison 
with  the  shorter-billed  birds. 

The  upper  mandible  is  moved  by  three 
muscles  on  either  side.  The  first  is  of  a  radiated 
form,  arises  from  the  septum  of  the  orbits,  and 
converges  to  be  inserted  into  the  external  and 
posterior  end  of  the  pterygoid  bone,  just  where 
this  is  articulated  to  the  tympanic  bone.  It 
draws  forward  the  pterygoid  bone,  which  pushes 
against  and  raises  the  upper  jaw. 

The  second  muscle  analogous  to  the  External 
Pterygoid  arises  from  the  space  between  the 
posterior  part  of  the  orbit  and  external  meatus 
auditorius,  and  is  inserted  into  the  internal 
process  and  contiguous  surface  of  the  tympanic 
bone ;  it  affects  the  pterygoid  process,  and  con- 
sequently the  upper  mandible  in  the  same 
way  as  the  preceding  muscles,  and  assists  in 
opening  the  bill. 

The  Pterygoideus  Internus  is    a  long  and 

*  See  Yarrell  '  On  the  Anatomy  of  the  Cormo- 
ant/  Zool.  Trans,  v.  iv.  p.  235. 


slender  muscle ;  it  arises  from  the  pterygoid 
process  and  body  of  the  sphenoid,  and  is  in- 
serted principally  into  the  inner  side  of  the 
lower  jaw  and  tympanic  bone ;  it  also  sends 
off  a  small  tendon  to  the  membrane  of  the 
palate.  This  muscle  draws  forward  the  lower 
jaw  and  depresses  the  upper  one. 

In  the  Cross-bill  ( Loxia  curvirostra)  there 
is  a  remarkable  want  of  symmetry  in  the 
muscles  of  the  jaws  on  the  two  sides  of  the 
head  corresponding  to  their  peculiar  position. 
Those  of  the  side  towards  which  the  lower 
jaw  is  drawn  in  a  state  of  rest  (which  varies 
in  different  individuals)  are  most  developed, 
and  act  upon  the  mandibles  with  a  force  that 
enables  the  bird  to  dislodge  the  seeds  of  the 
fir-cones,  which  constitute  its  food. 

The  articulation  of  the  lower  jaw  is  strength- 
ened and  its  movements  restrained  by  two 
strong  ligaments,  one  of  these  (a)  is  extended 
from  the  ligament  completing  the  lower  part 
of  the  orbit,  or  from  the  zygomatic  proce  ss  of 
the  temporal  bone,  and  is  inserted  at  the  outer 
protuberance  near  the  joint  of  the  lower  jaw, 
and  must  prevent  the  bill  from  being  too 
widely  opened.  The  second  ligament  extends 
from  the  zygomatic  process  of  the  temporal  bone 
directly  backwards  to  the  posterior  part  of  the 
articular  depression  of  the  lower  jaw,  and  is 
designed  to  guard  against  the  backward  dislo- 
cation of  the  lower  jaw. 

The  muscles  of  the  ribs.  —  The  levatores 
costarum  arise  from  the  posterior  part  of  the 
extremities  of  the  transverse  processes,  and 
converge  to  be  inserted  into  the  anterior 
margin  of  the  succeeding  posterior  rib.  Those 
of  the  first  and  second  ribs  represent  the 
Scalcni,  and  are  of  larger  size,  arising  from 
the  last  and  penultimate  cervical  vertebrae. 

The  Intercostales  externi  appear  to  be  con- 
tinuations of  the  Levatores  costarum,  and  are 
usually  divided  into  an  anterior  and  posterior 
moiety  corresponding  to  the  marked  separation 
and  moveable  articulation  between  the  vertebral 
and  sternal  portions  of  the  ribs ;  the  anterior 
division  arises  from  the  costal  appendage  and 
extends  to  the  anterior  extremity  of  the  rib  ; 
to  afford  a  more  advantageous  origin  to  this 
inspiratory  muscle  would  appear,  therefore,  to 
be  one  of  the  uses  of  the  costal  appendages, 
as  well  as  to  strengthen  the  connection  of  the 
ribs  to  each  other. 

The  Internal  intercostal*  commence  at  the 
sternal  extremities  of  the  ribs,  as  in  mammalia, 
but  extend  backwards  no  farther  than  the  costal 
appendages;  their  fibres  run  in  an  opposite 
direction  to  the  external  intercostals,  and  are 
shorter,  the  insertion  into  the  posterior  suc- 
ceeding rib  being  by  a  thin  but  wide  aponeu- 
rosis :  in  the  Penguin  they  are,  however, 
wholly  muscular.  Two  other  layers  of  inter- 
costal muscles,  corresponding  to  the  triangu- 
laris  sterni,  and  having  the  same  direction 
of  fibres,  are  extended  from  before  backwards 
and  outwards  to  the  four  anterior  sternal  por- 
tions of  the  ribs  ;  arising  from  the  superior  and 
external  angle  of  the  sternum. 

The  muscles  of  the  abdomen  are  small  and 


AVES. 


293 


weak,  in  consequence  of  the  protection  which  the 
extended  sternum  affords  to  the  viscera  of  that 
cavity. 

The  External  oblique  (19)  is  chiefly  remarka- 
ble for  the  transverse  arrangement  of  its  fibres ; 
these  arise  anteriorly  by  short  fleshy  digitations 
from  the  inferior  ribs,  and  by  a  large  but  very 
thin  tendon  from  the  posterior  ribs  and  the  edge 
of  the  ilium  and  pubis ;  they  are  inserted  by 
aponeurosis  into  the  anterior  margin  of  the  pubis, 
and  join  the  aponeurosis  of  the  opposite 
muscle  in  front  of  the  thin  and  tendinous 
rcctus  abdominls.  This  muscle,  by  drawing 
downwards  and  backwards  the  posterior  part 
of  the  sternum  and  sternal  ribs,  opens  the 
angle  between  these  and  the  vertebral  ribs, 
depresses,  in  consequence,  the  anterior  part 
of  the  sternum,  and  thus  dilates  the  thorax, 
and  becomes  a  muscle  of  inspiration. 

The  Internal  oblique  comes  off  fleshy  from 
the  anterior  moiety  of  the  edge  of  the  pubis, 
and  tendinous  from  the  posterior  moiety  of  the 
same  bone ;  it  is  much  smaller  than  the  pre- 
ceding, and  is  directed  forwards  and  inwards 
to  the  last  rib,  which  it  draws  backwards,  and 
thus  assists  the  preceding  in  the  compression 
of  the  abdomen  and  abdominal  air-cells,  and 
in  the  dilatation  of  the  thorax. 

The  Tramversalis  is  a  muscle  of  greater 
extent;  it  arises  from  the  whole  anterior  margin 
of  the  pubic  bones  by  carneous  fibres,  and  by 
digitations  from  the  three  posterior  ribs ;  its 
tendon  unites  with  that  of  its  fellow  in  the 
mesial  line,  extends  immediately  over  the  pe- 
ritoneum over  the  whole  abdomen  as  far  as 
the  posterior  margin  of  the  sternum  to  which 
it  is  attached. 

The  Rectus  abdominis  is  not  intersected  by 
tendinous  digitations ;  its  origin  is  by  a  broad 
thin  tendon  from  the  lower  and  posterior  half 
of  the  pubis ;  at  about  the  middle  third 
of  the  abdomen  it  becomes  carneous,  and 
is  inserted  into  the  posterior  margin  of  the 
sternum.  A  mesial  tendon  or  linea  alba  sepa- 
rates the  fleshy  portions  of  the  two  muscles. 

The  Diaphragm  arises  by  fleshy  digitations 
from  the  sternal  ribs;  in  the  Ostrich  these 
digitations  are  five  in  number  on  either  side  : 
the  carneous  fasciculi  do  not,  however,  extend 
so  far  upon  the  central  aponeurosis  as  even 
to  be  united  laterally  to  one  another,  and 
consequently  this  muscle  has  frequently  been 
denied  to  birds.  From  the  lungs  being  con- 
fined to  the  back  part  of  the  thorax,  the  dia- 
phragmatic aponeurosis  attached  to  their  inferior 
surface  is  not  extended  as  a  transverse  sep- 
tum between  the  chest  and  abdomen,  but  allows 
the  heart  to  encroach  upon  the  interspace  of 
the  lobes  of  the  liver,  as  in  reptiles.  The 
contraction  of  the  muscle  tends  directly  to  dilate 
the  lungs,  but  is  less  perfect  as  an  inspiratory 
action  from  the  aponeurosis  or  central  tendon 
being  perforated  by  large  cribriform  apertures 
for  the  passage  of  the  air  into  the  abdominal 
air-cells. 

The  Wing-Muscles. — The  muscles  of  the 
anterior  extremity,  especially  those  inserted  into 
the  humerus,  are  prodigiously  developed,  and 


form  the  most  characteristic  muscles  of  the 
bird.  The  muscles  of  the  shoulder,  however, 
are  but  small,  and  those  of  the  distal  segments 
of  the  wing  still  more  feeble. 

The  Trapezius  (20),  the  lower  half  of  which 
seems  only  to  be  present  in  birds,  arises  from 
the  spines  of  the  lower  cervical,  and  a  varying 
number  of  the  contiguous  dorsal  vertebrae,  and 
is  inserted  into  the  dorsal  margin  of  the  sca- 
pula and  the  corresponding  extremity  of  the 
clavicle  ;  the  clavicular  portion  can  commonly 
be  separated  from  the  scapular. 

The  Hhomboideus  lies  immediately  beneath 
the  preceding,  and  is  always  single ;  it  passes 
in  a  direction  contrary  to  the  trapezius  from  the 
spines  of  the  anterior  dorsal  vertebrae  to  the 
dorsal  edge  of  the  scapula. 

The  Levator  scapula  arises  by  digitations 
from  the  transverse  process  of  the  last  cervical 
vertebra,  and  from  the  first  two  ribs;  it  is  inserted 
into  the  posterior  part  of  the  dorsal  edge  of  the 
scapula,  which  it  raises  and  pulls  forwards. 

The  Serralus  magnus  antic  us  (21)  is  most 
developed  in  birds  of  prey ;  it  arises  by  large 
digitations  from  three  or  four  of  the  middle 
ribs,  and  converges  to  be  inserted  into  the  ex- 
tremity of  the  scapula. 

The  Serrutus  parvus  anticus  or  Pectoralis 
minor,  as  it  is  termed  in  Man,  arises  by  digita- 
tions from  the  first  and  second  ribs,  and  is  in- 
serted into  the  commencement  of  the  inferior 
margin  of  the  scapula.  This  is  the  largest  of 
the  muscles  of  the  scapula  in  the  Penguins. 

A  muscle,  which  may  be  regarded  either  as 
a  portion  of  the  Pectoralis  minor  or  as  the  ana- 
logue of  the  Subclavius  muscle,  arises  from  the 
anterior  angle  of  the  sternum,  and  is  inserted 
into  the  external  margin  of  the  sternal  extremity 
of  the  coracoid  bone. 

The  Supra-spinatus  (22)  arises  from  the  ante- 
rior part  of  the  outer  surface  of  the  scapula,  and 
is  inserted  behind  the  largely  developed  inter- 
nal tuberosity  of  the  humerus. 

The  muscle  which  seems  to  represent  both 
the  Infra-spinatus  and  Teres  major  (23)  has  a 
more  extensive  origin  from  the  outer  margin  of 
the  scapula  to  its  extremity,  and  is  inserted 
into  the  internal  tuberosity  of  the  humerus. 

The  Subscapularis  arises  from  the  anterior 
part  of  the  inner  surface  of  the  scapula,  and  is 
inserted  into  the  humeral  tuberosity.  It  is 
divided  into  two  portions  by  the  Pectoralis 
minor. 

The  Latissimus  dorsi  (24,  24,)  is  but  a  feeble 
muscle  in  this  class,  and  is  constantly  divided 
into  two  very  distinct  slips.  The  anterior  por- 
tion arises,  more  superficial  than  the  trapezius, 
from  the  spines  of  the  four  or  five  anterior 
dorsal  vertebrae,  and  is  inserted  near  the  tendon 
of  the  deltoid  into  the  outer  side  of  the  humerus. 
The  posterior  slip  comes  from  the  spines  of  the 
dorsal  vertebrae  above  the  origin  of  the  glutaus 
magnus,  and  sometimes  from  the  anterior  mar- 
gin of  the  same  muscle,  and  is  inserted  by  a 
broad  and  thin  tendon  immediately  in  front  of 
the  preceding  portion. 

The  Deltoidcs  (26)  is  comparatively  a  small 
muscle ;  it  arises  from  the  anterior  part  of  the 


294 


AVES. 


scapula,  and  is  inserted  along  the  middle  of  the 
outer  side  of  the  humerus ;  it  brings  the  wing 
upward  and  backward. 

Birds  have  the  Pectoralis  muscle  divided,  as 
in  many  of  the  mammalia,  into  three  portions, 
which  are  so  distinct  as  to  be  regarded  as  sepa- 
rate muscles  ;  they  all  arise  from  the  enormous 
sternum,  and  act  upon  the  proximal  extremity 
of  the  humerus. 

Thejirst  or  great  Pectoral  muscle  (25)  is  ex- 
traordinarily developed,  and  is  in  general  the 
largest  muscle  of  the  body.  In  birds  of  flight  it 
often  equals  in  weight  all  the  other  muscles 
of  the  body  put  together.  It  arises  from  the 
anterior  part  of  the  outer  surface  of  the  clavicle 
or  furculum,  from  the  keel  of  the  sternum  and 
from  the  posterior  and  external  part  of  the 
lower  surface  of  that  bone ;  it  is  inserted  by  an 
extended  fleshy  margin  into  the  inner  side  of 
the  anterior  crest  of  the  humerus.  It  forcibly 
depresses  the  humerus,  and  consequently  forms 
the  principal  instrument  in  flight. 

This  muscle  is  very  longand  wide  in  the  Nata- 
tores  generally,  but  in  many  of  these  birds,  as 
the  Penguin,  its  origin  is  limited  to  the  external 
margin  of  the  subjacent  pectoral  muscle,  which 
is  heie  remarkably  developed.  The  great  pec- 
toral is  very  long,  but  not  very  thick  in  the 
Rusores.  In  the  Herons  it  is  shorter,  but 
much  stronger  and  thicker.  Its  size  is  most 
remarkable  in  the  Humming-birds,  Swallows, 
and  diurnal  Birds  of  Prey,  where  it  is  attached 
to  almost  the  whole  outer  surface  of  the  sternum 
and  its  crest,  and  has  an  extended  insertion  into 
the  humerus. 

In  the  Ostrich  its  origin  is  limited  to  the  an- 
terior and  external  eighth  part  of  the  sternum, 
and  it  is  inserted  by  a  feeble  tendon  into  the 
commencement  of  the  crest  of  the  humerus,  to 
which  it  gives  a  strong  rotatory  motion  for- 
wards. 

The  second  Pectoral  muscle  is  situated  be- 
neath the  preceding;  it  has  the  form  of  an 
elongated  triangle :  it  arises  from  the  base  of 
the  crest  of  the  sternum  and  from  the  mesial 
part  of  the  inferior  surface  of  that  bone  ;  it  in- 
creases in  size  as  it  ascends,  then  again  be- 
comes suddenly  contracted,  passes  upwards 
and  backwards  round  the  coracoideam,  between 
that  bone  and  the  clavicle,  then  turns  down- 
wards and  outwards,  and  is  inserted,  fleshy, 
above  and  in  front  of  the  great  pectoral,  into 
the  upper  extremity  of  the  humeral  crest. 

The  interspace  between  the  clavicle,  cora- 
coid,  and  scapula,  through  which  its  tendon 
passes,  serves  as  a  pulley,  by  means  of  which 
the  direction  of  the  force  of  the  carneous  fibres 
is  changed,  and  although  these  fibres  ascend 
from  below  towards  their  insertion,  yet  they 
forcibly  raise  the  humerus,  and  thus  a  levator 
of  the  wing  is  placed  without  inconvenience 
on  the  lower  part  of  the  trunk,  and  the  centre 
of  gravity  proportionally  depressed. 

In  the  Penguins,  Guillemots,  and  Gulls, 
this  muscle  is  almost  the  largest  of  the  three, 
occupying  the  whole  length  of  the  sternum. 
It  is  remarkable  for  the  length  and  strength 
of  its  tendon,  which  is  inserted  so  as  to  draw 


forwards  the  humerus  with  great  force.  It  is 
proportionally  the  smallest  in  the  Raptores; 
and  is  very  small  and  slender  in  the  Struthious 
birds. 

We  have  already  alluded  to  the  use  which 
the  Penguin  makes  of  its  diminutive  anterior 
extremities  as  water-wings,  or  fins;  to  raise 
these  after  making  the  down-stroke  obvi- 
ously requires  a  greater  effort  in  water  than  a 
bird  of  flight  makes  in  raising  its  wings  in  air : 
hence  the  necessity  for  a  stronger  development 
of  the  second  pectoral  muscle  in  this  and  other 
Diving  Birds,  in  all  of  which  the  wings  are 
the  chief  organs  of  locomotion,  in  that  action, 
and  consequently  require  as  powerful  a  deve- 
lopment of  the  pectoral  muscles  as  the  gene- 
rality of  Birds  of  Flight. 

The  third  Pectoral  muscle,  which  is  in  ge- 
neral the  smallest  of  the  three,  arises  from  the 
anterior  part  of  the  inferior  surface  of  the  ster- 
num, and  also  by  a  more  extended  origin,  from 
the  posterior  moiety  of  the  inferior  surface  of 
the  coracoid ;  it  is  directed  forwards,  and  is 
inserted  by  a  short  and  strong  tendon  into  the 
internal  tuberosity  of  the  humerus,  which  it 
depresses. 

It  is  proportionally  large  in  the  Penguins 
and  Gulls,  but  attains  its  greatest  development 
in  the  Gallinaceous  order. 

Above  the  preceding  muscle  there  is  another 
longer  and  more  slender  one,  analogous  to  the 
Coraco-brachialis,  which  arises  from  the  middle 
of  the  posterior  surface  of  the  coracoid ;  its 
direction  upwards  is  less  vertical  than  that  of 
the  third  pectoral,  along  the  outer  side  of 
which  it  is  attached  to  the  anterior  tuberosity 
of  the  humerus.  This  muscle  is  wanting  in 
the  Struthionidtf,  is  of  small  size  in  the 
Heron  and  Goose,  is  much  more  developed 
in  the  Rapiores  and  many  Natatores,  espe- 
cially the  Penguins,  and  attains  its  greatest 
relative  size  in  the  Rasores,  where  it  arises 
from  almost  the  whole  of  the  coracoideum. 

Birds  in  general  possess  twojlexors  and  one 
extensor  (27)  of  the  fore-arm,  analogous  to  those 
which  are  found  in  the  mammalia.  They  have 
also  the  muscles  corresponding  to  the  pronators 
and  supinators  of  this  higher  class,  but  their 
action  is  limited  in  the  feathered  tribes  to  in- 
flexion and  extension  of  the  fore-arm,  and  to 
adduction  and  abduction  of  the  hand. 

A  remarkable  muscle,  partly  analogous  in  its 
origin  to  the  clavicular  portion  of  the  deltoid, 
but  differently  inserted,  is  called  by  Carus 
Extensor  plica  alaris  (30,  a  b)  and  forms 
one  of  the  most  powerful  flexors  of  the 
cubit.  It  is  divided  into  two  portions,  of 
which  the  anterior  and  shorter  arises  from 
the  internal  tuberosity  of  the  humerus ;  the 
posterior  and  longer  from  the  clavicular  ex- 
tremity of  the  coracoid  bone.  In  the  Ostrich 
and  Rhea,  however,  both  portions  arise  from 
the  coracoid.  The  posterior  muscle  (b)  sends 
down  a  long  and  thin  tendon  which  runs  pa- 
rallel with  the  humerus,  and  is  inserted,  gene- 
rally by  a  bifurcate  extremity,  into  both  the 
radius  and  ulna.  The  anterior  muscle  (a) 
terminates  in  a  small  tendon,  which  runs 


AVKS. 


along  the  edge  of  the  aponeurotic  expansion 
of  die  wing.  In  this  situation  it  acquires 
exactly  the  structure  and  elasticity  of  the  liga- 
mentum  subflavum  or  ligamentum  michae ;  it 
then  resumes  its  ordinary  tendinous  structure, 
passes  over  the  end  of  the  radius,  and  is  in- 
serted into  the  style  of  the  metacarpal  bone. 
It  combines  with  the  preceding  muscle  in 
bending  the  fore-arm;  and  further,  in  conse- 
quence of  the  elasticity  of  its  tendon,  puckers 
up  the  soft  part  of  the  fold  of  the  wing.  (See 
48,  Jig.  133.)  An  analogous  structure  is  met 
with  in  the  wing  of  the  bat. 

A  lesser  flexor  of  the  fore-arm,  and  stretcher 
of  the  alar  membrane  (31)  arises,  as  a  portion 
of  the  serratus  magnus  from  the  ribs,  and  ter- 
minates in  an  aponeurosis  inserted  into  the  alar 
membrane  and  fascia  of  the  fore-arm ;  it  is  re- 
presented in  the  figure  as  turned  aside. 

The  Extensor  metacarpi  radialis  longus  (32) 
is  the  first  muscle  which  detaches  itself  from 
the  external  condyle  of  the  humerus  (E),  and  it 
forms  the  radial  border  of  the  muscular  mass  of 
the  fore-arm ;  it  terminates  in  a  large  tendon 
about  the  middle  of  the  fore-arm,  and  this 
tendon  passes  along  a  groove  of  the  radius,  over 
the  carpus,  to  the  phalanx  of  the  so  called 
thumb,  or  spurious  wing,  into  the  radial  margin 
of  which  it  is  inserted.  It  raises  the  hand, 
draws  it  forwards  towards  the  radial  margin  of 
the  fore-arm,  and  retains  it  in  the  same  plane. 
In  the  Penguin  this  muscle  is  extremely  feeble, 
and  the  tendon  is  lost  in  that  of  the  tensor  plica 
alar  is. 

The  Extensor  metacarpi  radialis  brevis  (33) 
arises  below  the  preceding  from  the  ulnar  edge 
of  the  radius,  and  is  inserted  into  the  phalanx 
of  the  thumb  immediately  beyond  the  tendon 
of  the  preceding  muscle.  The  two  tendons  are 
quite  distinct  from  one  another  in  the  Birds  of 
Prey,  the  Ostrich  and  Parrots,  but  unite  at 
the  lower  end  of  the  fore-arm  in  the  Anatida, 
Phasianida,  and  Gruida. 

The  muscle  analogous  to  the  Extensor  carpi 
ulnaris  (34)  comes  off  from  the  inferior  extre- 
mity of  the  outer  condyle  of  the  humerus, 
passes  along  the  middle  of  the  exterior  surface 
of  the  fore-arm,  and  its  tendon,  after  passing 
through  a  pulley  at  the  distal  end  of  the  ulna, 
is  inserted  into  the  ulnar  phalanx.  It  draws 
the  hand  towards  the  ulnar  edge  of  the  fore- 
arm, and  is  the  principal  abductor  or  folder  of 
the  pinion. 

The  Flexor  metacarpi  radialis  (35)  is  a  short 
and  weak  muscle,  which  arises  from  the  inferior 
part  of  the  ulna,  descends  along  the  internal 
side  of  that  bone,  winds  round  its  lower  extre- 
mity and  the  radial  edge  of  the  carpus,  passes 
beneath  the  tendon  of  the  radial  extensors,  and 
is  inserted,  external  to  the  latter,  high  up  into 
the  dorsal  aspect  of  the  radial  phalanx  of  the 
metacarpus.  In  the  Ostrich  it  arises  from  the 
lower  third  of  the  ulna.  In  the  Penguin  it  is 
wanting. 

The  Flexor  metacarpi  ulnaris  (36)  arises 
beneath  the  fore-arm  from  the  internal  pulley 
of  the  ulna,  continues  fleshy  to  the  pinion,  and 
is  inserted,  first  into  the  ulnar  carpal  bone,  then 


into  the  ulnar  phalanx.     The  latter  insertion  is 
wanting  both  in  the  Ostrich  and  Penguin. 

The  muscles  of  the  pinion  or  hand  are  few, 
and  very  distinct  from  one  another;  the  thumb 
or  spurious  wing  is  moved  by  four  small  mus- 
cles, viz.  two  extensors,  an  abductor,  which 
draws  the  thumb  forwards,  and  an  adductor. 
The  second  digit  receives  three  short  muscles, 
two  of  which  are  extensors,  and  the  third  an 
abductor,  in  this  action  it  is  aided  by  one  and 
opposed  by  another  of  the  extensors.  The 
lesser  digit  receives  an  abductor,  which  comes 
from  the  ulnar  edge  of  the  preceding  phalanx. 

Muscles  of  the  lower  extremity. — Notwith- 
standing the  simplicity  of  the  motions  of  the 
lower  or  posterior  extremity,  the  muscles  of 
this  part  are  numerous,  and  present  several 
peculiarities  in  birds.  The  femur  can  be  moved 
freely  forward  and  backward,  but  its  rotation  is 
limited  by  a  strong  ligamentum  teres,  and  the 
structure  of  the  hip-joint  does  not  permit  it  to 
be  carried  under  the  body,  or  far  outwards. 

In  consequence  of  the  form  of  the  pelvis, 
the  psoas  magnus  and  parvus,  the  obturator 
externus  and  the  quadratics  lumborwn  do  not 
exist  in  birds. 

A  large  muscle,  regarded  by  Cuvier  as  the 
Obturator  internus,  takes  its  origin  from  the 
internal  surface  of  the  ischio-pubic  bone,  it  is 
directed  from  behind  forwards,  and  gives  off  a 
strong  and  long  tendon  which  passes  through 
the  small  opening  at  the  anterior  part  of  the 
obturator  foramen,  which  is  situated  between 
the  pubis  and  ischium,  (f,  fig.  131.)  In  this 
situation  a  muscle,  arising  from  the  external 
border  of  the  opening,  attaches  itself  to 
the  preceding,  and  is  inserted  conjointly  with 
it  into  the  posterior  and  outer  aspect  of  the 
trochanter.  Meckel  compares  this  muscle  with 
the  pectineus,  especially  as  it  exists  in  the  Sau- 
rian Reptiles,  but  observes  that  as  it  arises 
from  both  the  internal  and  external  surfaces  of 
the  circumference  of  the  obturator  foramen,  it 
may  represent  both  the  internal  and  external 
obturator  muscles.  It  is  of  an  extraordinary 
size  in  the  Ostrich. 

The  femur  is  raised  by  three  muscles. 

The  most  superficial  and  highest  of  these 
elevators  (37)  arises  by  a  broad  and  thin  aponeu- 
rosis from  the  anterior  and  external  surface  of 
the  ilium,  it  is  of  a  square  form,  descends  al- 
most in  a  straight  line,  and  is  inserted  into  the 
posterior  part  of  the  trochanter.  Meckel  re- 
gards it  as  analogous  to  the  Glutaus  medius: 
Carus  calls  it  the  Glutteus  maximus.  But  the 
latter,  according  to  Meckel,  is  represented  by 
the  posterior  part  of  what  Carus  terms  the 
Rectusfemoris  latissimus  (40). 

Anterior  to  the  Glutaus  medius  of  Meckel, 
there  is  a  much  smaller  muscle,  which  extends 
from  the  anterior  margin  of  the  ilium  to  the 
trochanter,  where  it  is  inserted  in  front  of  the 
preceding.  It  is  of  an  elongated  quadrilateral 
form,  and  it  represents  the  Glutaus  minor  of 
quadrupeds.  It  is  wanting  in  many  of  the 
Natatvres,  and  arrives  at  its  greatest  degree  of 
development  in  the  Raptorial  Order. 

A  third  muscle,  still  smaller  and  longer  than 


296 


AYES. 


the  preceding  and  situated  beneath  it,  which 
arises  from  the  outer  margin  of  the  ilium,  and 
is  inserted  into  that  part  of  the  femur  which 
corresponds  to  the  lesser  trochanter,  is  regarded 
by  Meckel  as  the  Iliacus  internus,  which  Cu- 
vier  states  to  be  wanting  in  Birds.  It  is,  how- 
ever, present  in  most,  and  is  seen  highly  deve- 
loped in  the  Ostrich. 

The  muscles  analogous  to  the  Pyramidalis 
and  Gemellus  superior  exist  in  Birds. 

There  are  most  commonly  three  adductors  of 
the  thigh.  The  inferior,  external,  and  posterior 
one  arises  from  the  middle  of  the  external  sur- 
face of  the  anterior  margin  of  the  ischio-pubic 
bone,  and  is  inserted  into  the  greater  part  of 
the  lower  half  of  the  femur  at  38. 

The  second  and  third  adductors  are  situated 
internally  to  the  preceding ;  the  latter  of  these 
may  be  compared  to  the  Pectineus. 

The  Sartorius  (39)  arises  from  the  anterior 
point  of  the  ilium,  and  passes  down  to  be 
attached  to  the  head  of  the  tibia ;  it  is  an  ex- 
tensor of  the  leg  upon  the  thigh. 

The  Rectus  femoris  (40)  arises  by  a  thin 
but  wide  aponeurosis  from  the  spines  of  the 
sacrum,  after  a  short  course  it  joins  the  Crurceus 
and  Vasti  (42),  and  is  inserted  into  the  head  of 
the  fibula.  It  corresponds  according  to  Meckel 
with  the  Tensor  vagina  femoris  and  the  Glutens 
magnus. 

The  Gracilis  (41)  arises  from  the  superior 
part  of  the  pubis,  descends  along  the  inner 
side  of  the  thigh,  and  towards  the  lower  extre- 
mity of  this  part,  is  continued  into  a  long  and 
strong  tendon,  which  passes  in  front  of  the 
knee-joint,  and  over  the  extensor  tendon  of  the 
leg  to  the  outer  side  of  the  fibula,  whence  it  pro- 
ceeds inwards,  anterior  to  the  tendon  of  the  pero- 
neal  flexor,  to  become  united  to  the  outer  origin 
of  the  flexor  perforatus  of  the  toes.  Meckel  con- 
siders that  the  muscle  now  described  represents 
the  Rectus  Jemor is  of  mammalia,  and  regards 
as  the  Gracilis  a  small  and  thin  muscle,  whose 
origin  has  been  transferred  lower  down,  from  the 
pubis  to  the  femur,  from  the  internal  side  of 
which  it  passes  to  the  internal  and  superior  part 
of  the  tibia.  Be  this  as  it  may,  the  disposition 
of  the  former  muscle  is  such,  passing,  viz.  first, 
over  the  convexity  of  the  knee-joint,  and  after- 
wards over  the  projection  of  the  heel,  that  from 
its  connection  with  a  flexor  of  the  toes,  these 
must  necessarily  be  bent  simultaneously  with 
every  inflection  of  the  joints  of  the  knee  and 
ankle.  As  these  inflections  naturally  take 
place  when  the  lower  extremities  yield  to  the 
superincumbent  weight  of  the  body,  birds 
are  thus  enabled  to  grasp  the  twigs  on  which 
they  rest  whilst  sleeping,  without  making  any 
muscular  exertion. 

There  are  three  flexors  of  the  leg :  one  (43) 
which,  although  single,  is  from  its  insertion 
into  the  back  of  the  fibula,  analogous  to  the 
Biceps  flexor  cruris  of  the  human  subject :  ano- 
ther on  the  inside  is  attached  to  the  tendon  of 
the  extensors  of  the  foot  as  well  as  the  tibia ; 
this  muscle  might  be  called  the  Semimembranosus 
(44) :  the  third  flexor  is  in  the  middle  (45), 
it  comes  from  the  ischium,  and  as  it  descends 


it  receives  a  broad  fleshy  slip  from  the  back  of 
the  femur.  It  is  inserted  on  the  back  of  the 
tibia,  the  tendon  covering  those  of  the  extensors 
of  the  heel. 

The  muscles  of  the  feet  present  in  Birds 
essential  resemblances  to  the  same  parts  in 
Reptiles.  They  are  divided  into  muscles  of 
the  tarsus,  of  the  metatarsus,  and  of  the  toes, 
the  latter  being  subdivided  into  long  and  short. 
The  principal  points  in  which  they  differ  from 
the  same  muscles  in  Reptiles  and  the  Mammalia 
are  the  following:  their  origins  and  carneous 
portions  are  not  situated  on  the  foot  but  higher 
up  on  the  tibia  and  even  on  the  femur.  The 
great  length  of  the  metatarsus  occasions  the 
smaller  muscles  to  be  of  a  greater  proportional 
length  than  in  other  animals.  The  muscular 
portions  are  most  developed  in  the  Raptores, 
Scansoresy  and  Natatores  ;  the  Insessores  and 
Rasores  present  an  intermediate  proportion ; 
the  Cursores  and  Grallatores  have  the  longest 
tendons. 

The  Gastrocnemius  (46)  has  three  distinct 
origins :  two  of  these  are  superficial,  one  from 
the  outer,  the  other  from  the  inner  condyle  of 
the  femur ;  the  third  origin  is  lower  down  from 
the  inner  side  of  the  tibia  and  fibula  (47), 
They  unite  to  terminate  in  a  thin  and  broad 
aponeurosis,  which  after  becoming  closely  con- 
nected with  a  fibre-cartilage  appertaining  to  the 
flexor  digitorum,  proceeds  to  be  inserted  into 
both  the  outer  and  inner  margins  of  the  tarso- 
metatarsal  bone. 

The  Tibialis  anticus  (48)  arises  from  the  an- 
terior part  of  the  upper  extremity  of  the  tibia, 
below  which  its  tendon  passes  through  an 
aponeurotic  loop  extended  from  the  outer  to 
the  inner  margin  of  the  tibia.  It  has  also  a 
second  origin,  by  means  of  a  slender  tendon, 
from  the  anterior  part  of  the  external  condyle 
of  the  femur.  It  is  generally  inserted  pretty 
high  up  into  the  tarso-metatarsal  bone  between 
the  outer  and  inner  margins ;  but  in  the  Psit- 
tacida  it  is  attached  lower  down  to  the  internal 
border,  so  as  to  turn  the  foot  inwards  as  well  as 
raise  it,  a  disposition  which  is  extremely  favor- 
able fov  the  act  of  climbing. 

The  Peroneus  (49)  is  a  much  smaller  muscle ; 
it  extends  from  the  lower  region  of  the  fibula, 
and  the  outer  and  anterior  edge  of  the  tibia  to 
the  tarso-metatarsal  bone,  into  the  outer  side  of 
the  base  of  which  it  is  inserted. 

The  Flexor  perforatus  sen  longus  digitorum 
(50)  forms  the  superficial  and  external  mus- 
cular mass  of  the  leg :  it  arises  by  one  mass 
from  the  posterior  part  of  the  external  side  of 
the  femur,  immediately  in  front  of  the  outer 
head  of  the  gastrocnemius ;  another  portion 
arises  from  the  outside  of  the  lower  extremity 
of  the  femur  ;  these  two  heads  unite  below  the 
middle  of  the  leg  and  constitute  one  fleshy  belly 
which  gives  off  three  tendons;  these  proceed  to 
the  proximal  phalanges  of  the  three  outer  toes 
where  they  bifurcate  to  give  passage  to  the  ten- 
dons of  \heflexor  perforans. 

The  Flexor  pollicis  (51)  arises,  by  its  anterior 
head,  from  the  anterior  and  upper  part  of  the 
tibia,  and  by  its  posterior  head  from  the  ex- 


AVES. 


297 


ternal  condylc  of  the  femur;  when  it  has 
readied  the  region  of  the  culcaneum,  it  passes 
backwards  through  a  synovial  capsule,  and 
is  inserted  into  the  proximal  phalanx  of  the 
thumb,  where  it  is  perforated  by  the  tendon 
of  the  perforans  muscle. 

The  Flexor  proj'undus  perforans  (52)  arises 
as  two  distinct  muscles,  the  one  from  the  back 
of  the  femur  and  the  other  from  the  back 
of  the  tibia  and  fibula;  the  tendons  of  these 
two  portions  unite  behind  the  metatarsal  bone, 
and  send  off  tendons  to  the  last  phalanges  of 
the  toes,  which  perforate  those  of  the  flexor 
sublimis. 

The  Extensor  longus  com  munis  digitorum 
arises  above  from  the  anterior  side  of  the  tibia, 
below  the  tibialis  anticus,  passes  beneath  a 
strong  restraining  ligament,  then  lower  down 
beneath  an  osseous  bridge,  and  lastly  across 
a  strong  ligament  situated  at  the  inferior  ex- 
tremity of  the  tarso-metatarsal  bone.  Below 
this  part  its  tendon  divides  into  three  slips 
which  are  inserted  into  the  distal  phalanges 
of  the  thiee  outer  toes  (53). 

There  are  six  long  muscles  lying  on  the 
metatarsal  bone ;  they  are  largest  and  best 
marked  in  those  birds  which  walk  most,  as 
the  Arcs  ter retires.  Two  of  these  muscles 
are  on  the  posterior  surface ;  one  goes  to  the 
base  of  the  external  toe,  which  it  abducts; 
the  other  is  inserted  into  the  root  of  the  back 
toe,  which  it  bends.  The  other  four  muscles  are 
on  the  anterior  part  of  the  metatarsus  :  the  first 
extends  the  back  toe;  the  second  goes  to  the 
base  of  the  first  toe,  and  abducts  it;  the 
third  is  spread  on  the  root  of  the  middle  toe, 
which  it  extends ;  the  fourth  lies  along  the  out- 
side of  the  metatarsus,  perforates  the  end  of 
the  bone,  and  is  implanted  into  the  inside  of 
the  external  toe,  and  abducts  it. 

Progression  on  land  is  generally  effected  in 
birds  by  the  alternate  advancement  of  the  two 
feet;  but  sometimes  they  proceed  by  leaping 
or  hopping,  rather  than  walking  ;  both  feet  are 
then  firmly  fixed  on  the  ground,  and  the  body 
is  propelled  forwards  by  a  sudden  extension 
of  all  the  joints  of  the  legs.  Birds  which  have 
sharp  claws,  as  the  Accipitres,  #c.,  retract  them 
when  they  hop,  to  prevent  their  being  blunted. 
The  Cat  tribe,  among  mammalia,  have  a  me- 
chanism effecting  a  similar  purpose.  Some 
birds  derive  assistance  in  terrestrial  progression 
by  the  flapping  of  the  wings,  and  this  is 
especially  the  case  with  the  Ostrich,  which 
runs  by  the  alternate  advancement  of  its  legs. 

The  act  of  climbing  is  performed  by  means 
of  a  peculiar  disposition  of  the  toes,  aided  by 
prehension  with  the  beak,  as  in  the  Maccaws 
and  Parrots,  or  by  the  prop  formed  by  the  stiff 
tail-feathers,  as  in  the  Woodpeckers. 

The  act  of  swimming  is  rendered  easy 
to  birds  by  the  specific  levity  of  their  body, 
arising  from  the  extension  of  the  air-cells ; 
by  the  shape  of  the  chest,  which  resembles 
the  bottom  of  a  boat ;  and  by  the  conversion 
of  the  hinder  extremities  into  oars  in  con- 
sequence of  the  membranes  uniting  the  toes 
together.  The  effect  of  these  web-feet  in 
water  is  further  assisted  by  the  toes,  having  their 


membranes  lying  close  together  when  carried 
forwards,  whilst,  on  the  contrary,  they  are  ex- 
panded in  striking  backwards.  The  oar-like 
action  of  the  hinder  legs  is  still  further  favoured 
by  their  backward  position ;  and  by  the  meta- 
tarsus and  toes  being  placed  almost  on  the  same 
perpendicular  or  vertical  line  with  the  tibia,  an 
arrangement,  however,  which  is  unfavourable 
for  walking. 

Sailing. — Some  birds,  as  the  Swan,  partially 
expand  their  wings  to  the  wind  while  swimming, 
and  thus  move  along  the  waters  by  means  of 
sails  as  well  as  oars. 

The  act  of  diving  is  performed  by  the  rapid 
and  forcible  action  of  the  wings,  beating  the 
water  as  in  flight,  by  the  feet  striking  the  waters 
backwards  and  upwards,  and  assisted  probably 
by  the  compression  of  the  air-cells. 

Flight,  the  most  important  and  characteristic 
mode  of  locomotion  in  birds,  results  principally 
from  the  construction  and  form  of  the  anterior 
extremities,  which  have  already  been  described. 

The  form  of  the  body  has  also  especial 
reference  to  this  power,  the  tiunk  being  an 
oval  with  the  large  end  forwards.  The  spine 
being  short  and  inflexible,  the  muscles  act 
to  great  advantage,  and  the  centre  of  gravity 
is  more  easily  changed  from  above  the  feet 
as  in  the  stationary  position,  to  between  the 
wings  as  during  flight.  The  head  of  the  bird 
is  generally  small,  and  the  beak  pointed,  which 
is  a  commodious  form  for  dividing  the  air. 
The  long  and  flexible  neck  compensates  for  the 
want  of  hands  and  the  rigidity  of  the  trunk, 
and  contributes  to  change  the  centre  of  gravity, 
according  to  the  required  mode  of  progression, 
by  simply  projecting  the  head  forwards,  or 
drawing  it  back.  The  position  of  the  great 
pectoral  muscles,  as  before  observed,  always 
tends  to  keep  the  centre  of  gravity  at  the  in- 
ferior part  of  the  body.  The  power  which 
birds  enjoy  of  raising  and  supporting  them- 
selves in  the  air  is  undoubtedly  aided  by  the 
lightness  of  the  body.  The  large  cavities  in 
the  bones  diminish  their  weight  without  taking 
away  from  their  strength, — a  hollow  cylinder 
being  stronger  than  a  solid  one  of  the  same 
weight  and  length.  But  the  specific  levity 
principally  depends  on  the  great  air-cells,  which 
occupy  almost  every  part  of  the  body,  and 
which  are  all  in  communication  with  the 
lungs.  The  air  which  birds  inspire  distends 
these  cells,  being  expanded  by  the  great  heat 
of  the  body.  Lastly,  the  feathers,  and  especi- 
ally the  quills,  from  their  lightness  and  elastic 
firmness,  contribute  powerfully  to  the  act  of 
flying  by  the  great  extent  which  they  give  to  the 
wings,  the  length  and  breadth  of  which  are  fur- 
ther increased  by  the  expanded  integument 
situated  in  the  bend  of  the  arm  and  in  the 
axilla. 

When  a  bird  commences  its  flight  it  springs 
into  the  air,  either  leaping  from  the  ground,  or 
precipitating  itself  from  some  elevated  point. 
During  this  action  it  raises  the  humerus,  and 
with  it  the  entire  wing,  as  yet  unfolded ;  it  next 
spreads  it  horizontally  by  an  extension  or  ad- 
duction of  the  fore-arm  and  hand  ;  the  greatest 
extent  of  surface  of  the  wing  being  thus  acquired, 


298 


AVES. 


it  is  rapidly  and  forcibly  depressed;  the  resistance 
of  the  air  thus  suddenly  struck  occasions  a 
reaction  on  the  body  of  the  bird,  which  is 
thereby  raised  in  the  same  manner  as  in  leap- 
ing from  the  ground.  The  impulse  being  once 
given,  the  bird  folds  the  wings  by  bending  the 
different  joints,  and  raises  it  preparatory  to 
another  stroke. 

Velocity  of  flight  depends  upon  the  rapidity 
with  which  the  strokes  of  the  wings  suc- 
ceed each  other.  A  simple  downward  stroke 
would  only  tend  to  raise  the  bird  in  the  air ; 
to  carry  it  forwards  the  wings  require  to 
be  moved  in  an  oblique  plane,  so  as  to  strike 
backwards  as  well  as  downwards.  The  turn- 
ing in  flight  to  the  right  or  to  the  left  is  prin- 
cipally effected  by  an  inequality  in  the  vibra- 
tions of  the  wings.  To  wheel  to  the  right  the 
left  wing  must  be  plied  with  greater  frequency 
or  force,  and  vice  versa. 

The  outspread  tail  contributes  to  sustain 
the  posterior  part  of  the  body ;  when  depressed 
during  a  rapid  forward  flight,  the  anterior  part 
of  the  body  is  raised,  and  flight  retarded ; 
•when  the  tail  is  raised  the  anterior  part  of  the 
body  is  lowered.  Some  birds  bend  the  tail  to 
one  side,  using  it  as  a  rudder  when  the  hori- 
zontal course  of  flight  is  required  to  be  changed. 

The  first  launch  of  the  bird  into  the  air  is  pro- 
duced by  an  ordinary  leap  from  the  ground, 
and  depends,  in  some  degree,  on  the  length 
of  the  legs.  Those  birds  which  have  very 
short  legs  and  very  long  wings,  as  the  Swallows, 
&c.,  cannot  leap  high  enough  to  gain  the 
requisite  space  for  the  expansion  of  their  wings, 
and  consequently  have  much  difficulty  in  raising 
themselves  from  the  ground,  and  generally  pre- 
fer throwing  themselves  from  some  high  point. 
The  manner  of  flight  varies  exceedingly  in 
different  birds,  some  dart  forward  by  jerks, 
closing  their  wings  every  three  or  four  strokes ; 
the  Woodpeckers,  Wagtails,  and  most  of  the 
small  Insessores  are  characterized  by  this  kind 
of  undulatory  motion  :  other  birds,  as  the  Swal- 
low, Crow,  &c.  fly  smooth  and  even :  the  Kite 
and  Kestrel  Hawk  and  the  great  Albatross  some- 
times appear  to  buoy  themselves  in  the  air  with- 
out any  perceptible  motion  of  the  wings. 

The  rapidity  with  which  a  strong  Bird  of  Prey 
flies  in  pursuit  of  his  quarry  is  inconceivably 
great.  The  anecdote  of  the  Falcon  belonging  to 
Henry  IV.  King  of  France,  which  flew  in  one 
day  from  Fontainbleau  to  Malta,  a  distance  of 
1350  miles,  is  well  known,  and  many  similar 
instances  are  on  record.  The  flight  of  a  Hawk, 
when  its  powers  are  fully  exerted,  is  calculated 
at  one  hundred  and  fifty  miles  an  hour.  The 
Eider-Duck's  usual  flight  has  been  ascertained 
to  be  at  the  rate  of  ninety  miles  an  hour. 

The  famous  Race-horse  Eclipse  is  said  to 
have  gone  at  the  rate  of  a  mile  in  a  minute  for 
a  very  short  distance;  but  this  speed,  if  it 
could  be  continued,  would  not  be  half  so 
great  as  that  which  many  birds  put  in  practice 
during  their  long  journeys  of  migration. 

Of  the  Nervous  System. — There  is  a  remark- 
able uniformity  in  the  form  and  structure  of  the 
brain  (fig.  \  34,  «,  b,  c,  d)  and  medulla  spinalis 
(eye)  in  the  different  orders  of  birds.  These  great 


divisions  of  the  cerebro- 
spinal  axis  are  always 
readily  distinguishable 
from  one  another  by  the 
greater  breadth  and  glo- 
bular form  of  the  brain, 
which  is  proportionally 
much  larger  than  in  the 
other  oviparous  verte- 
brata.  The  high  degree 
of  development  which 
the  spinal  cord  and 
cerebellum  present,  as 
compared  with  the  cold- 
blooded Reptilia,  has 
an  evident  relation  to 
the  extraordinary  loco- 
motive powers  with  which 
the  feathered  class  is  en- 
dowed . 

In  a  Pigeon  weighing 
eight  ounces  with,  and 
seven  ounces  without  its 
feathers,  or  three  thou- 
sand three  hundred  and 
sixty  grains,  the  cerebro- 
spinal  axis  weighs  forty- 
eight  grains,  the  weight 
of  the  spinal  cord  be- 
ing eleven,  and  that  of 
the  brain  thirty-seven 
grains. 

Of  the  Brain. —  The 
brain  of  the  bird  differs 
from  that  of  the  reptile 
in  the  superior  size  of 
the  cerebrum,  and  the 
more  complex  structure4 
of  the  cerebellum ;  it 
differs  from  the  brain  of 
a  mammal  in  the  smaller 
size  of  the  cerebellum, 
resulting  from  the  want 
of  the  lateral  lobes,  and 
in  the  absence  or  rudi- 
mentary condition  of  the 
fornix;  and  it  differs 
from  the  brain  of  every 
other  vertebrate  class  in  1 
the  lateral  and  inferior 
position  of  the  optic  lobes 
or  bigeminal  bodies.*  * 

It  cannot  be  at  once 
distinguished,  as  Cu- 
vier  asserts,  by  being 
composed  of  six  out- 
ward and  visible  masses, 
since  the  two  hemi- 
spheres, (a,  a,)  the  two 
optic  lobes,  ( b,  b,)  the 
cerebellum,  (c,)  and 
medulla  oblongata,  (d,) 


*  We  have  lately  as- 
certained that  the  corpus 
callosum  is  wanting  in  some 
of  the  marsupial  animals; 
its  presence  is  therefore  no 
longer  characteristic  of  the 
class  mammalia. 


'g-  134.; 


Brain  and  Spinal  Cord 
of  a  Goose, 


AVKS. 


299 


are  equally  obvious  in  the  brains  of  reptiles. 
They  are,  however,  differently  disposed  in  birds ; 
the  optic  lobes,  which  in  reptiles  intervene  and 
are  visible  between  the  cerebrum  and  cerebel- 
lum, being  in  birds  displaced,  as  it  were,  by 
the  hemisphere  and  cerebellum  coming  into 
close  contact,  so  that  the  optic  lobes  are  pushed 
downwards  and  to  one  side.  The  transverse 
convolutions  of  the  cerebellum  at  once  distin- 
guish, however,  the  brain  of  a  bird  from  that 
of  any  reptile  and  most  fishes ;  but  it  is  a  curi- 
ous fact  that  the  cerebellum  in  the  sharks  is 
similarly  composed  of  a  vermiform  process  only, 
transversely  folded  or  convoluted. 

The  cerebral  hemispheres  sometimes  present 
the  form  of  a  flattened  oval,  as  in  the  Parrot 
tribe,  but  in  general  are  of  a  convex  cordiform 
shape,  with  the  apex  directed  forward. 

Fig.  135.  The  optic  lobes  (b, 

Jig.  135)  are  rounded 
tubercles,  situated  be- 
low and  behind  the 
hemispheres,  in  the  la- 
teral i  n  terspace  between 
these  and  the  cerebel- 
lum. 

The  cerebellum    is 

Base  of  the  brain  of  a    composed  of  the  middle 
Pigeon.  lobe  only>  and  1S  of  a 

compressed  arched  form. 

The  medulla  oblongata  presents  neither  a 
tuber  annulare  nor  corpora  olivaria  or  pyrami- 
dalia,  but  is  a  large  uniform  tract  situated  be- 
tween and  behind  the  optic  lobes. 

On  the  lower  part  of  the  side  of  each  cere- 
bral hemisphere  there  is  a  depression  which 
corresponds  to  the  fissura  magna  Sylvii,  and  is 
the  only  appearance  which  the  hemispheres 
present  of  a  division  into  lobes.  Elsewhere 
there  are  no  traces  of  convolutions,  the  cere- 
brum in  this  respect  resembling  that  of  Kep- 
tiles  and  Fishes,  and  some  of  the  least  intel- 
ligent orders  of  Mammalia,  as  the  Rodent  ia, 
Marsupiata,  and  Edentata.  The  optic  lobes 
are  also  devoid  of  the  transverse  fissure  which 
bisects  the  optic  lobes  of  mammalia. 

The  cerebellum  is  marked  by  close  and 
transverse  anfractuosities,  such  as  characterize 
the  corresponding  portion  of  the  cerebellum  in 
mammalia,  called  the  vermiform  process. 

Fig.  136.  When   the  cerebral 

hemispheres  are  divari- 
cated from  each  other, 
(Jig.  136,^)  they  are 
seen  to  be  disunited 
through  the  whole  of 
their  vertical  extent, 
and  to  be  joined  only 
by  the  round  anterior 
commissure  of  the 
brain  (k,Jig.  136.)  In 

fact  both  the  corpus  callosum  and  fornix  are 
wanting ;  or  at  most  a  rudiment  only  of  the 
latter  part  can  be  perceived  in  the  brains  of 
some  birds,  as  the  Eagles,  Vultures,  and  Parrots. 
The  mesial  surfaces  of  the  hemispheres,  which 
are  in  contact  with  each  other,  present  a  few 
striae  which  diverge  from  the  commissure. 
These  surfaces  are  composed  of  an  extremely 


Brain  of  a  Pigeon. 


thin  layer  of  medullary  substance,  (g,)  forming 
the  internal  parietes  of  the  ventricle,  and  ex- 
tended outwardly  over  the  corpus  striutum  (i.) 
This  body  is  of  very  great  size  in  birds,  consti- 
tuting of  itself  almost  the  entire  substance  of 
the  hemisphere,  projecting  into  the  ventricle, 
(/i,)  not  only  from  below,  but  from  the  anterior 
and  outer  sides  of  the  cavity,  and  being  covered 
by  a  smooth  layer  or  fold  of  medullary  matter, 
Up)  which  increases  in  thickness  anteriorly. 
The  ventricle  does  not  extend  below  the  corpus 
striatum  to  form  an  inferior  horn ;  and,  as  in 
most  mammalia  there  is  no  extension  of  the 
cavity  backwards  to  form  a  posterior  horn, 
there  is  consequently  no  cornu  ammonis.  The 
vessel  forming  the  plexus  choroides  penetrates 
the  ventricle  beneath  the  posterior  part  of  the 
thin  internal  wall,  and  the  lateral  ventricles 
communicate  together  there,  and  with  the  third 
ventricle.  They  are  continued  anteriorly  to  the 
root  of  the  olfactory  nerve,  which  is  itself  a 
continuation  of  the  apex  of  the  hemisphere. 

Just  above  the  orifice  of  communication  there 
is  a  smooth  flattened  projection,  rounded  exter- 
nally, which  advances  into  the  ventricle  from  the 
internal  wall ;  this  is  a  rudiment  of  the  fornix. 

The  round  anterior  commissure  (k)  is  pro- 
longed on  either  side  into  the  substance  of  the 
hemispheres,  as  in  man  and  quadrupeds. 

The  optic  thalami  (I)  are  of  small  size,  and 
not  united  by  a  soft  commissure:  between  them 
is  the  cavity  called  third  ventricle  (m) ;  and 
above  and  behind  they  give  off  the  peduncles 
of  the  pineal  gland.  This  body  does  not  hang- 
freely  suspended  by  the  pedicles,  but  seems  to 
form  a  rounded  and  thickened  anterior  border 
of  the  valvulaVieussenii  or  lamelliform  commis- 
sure of  the  optic  lobes.  Carus  describes  the 
pineal  gland  as  adhering  firmly  to  the  conflu- 
ence of  the  great  veins  situated  at  the  anterior 
orifice  of  the  aqueduct  of  Sylvius.  In  Pigeons 
he  states  that  it  is  composed  of  many  segments, 
but  that  in  general  it  is  of  a  simple  and  "conical 
form ;  the  figure  which  he  gives  of  it,  from  the 
Turkey,  exhibits  a  pyriform  shape.*  The  valve 
which  closes  the  upper  part  of  the  passage 
from  the  third  to  the  fourth  ventricle,  is  a  thin 
lamella  of  great  width,  in  consequence  of  the 
distance  to  which  the  optic  lobes  are  sepa- 
rated from  one  another.  Anteriorly  the  third 
ventricle  communicates  with  the  infundibulum. 

The  fourth  ventricle  (n)  resembles  that  in 
the  brain  in  mammalia,  but  is  of  less  width ; 
its  floor  is  indented  with  the  longitudinal  fissure 
called  calamus  scriptorius. 

Besides  the  cavities  or  ventricles  above  men- 
tioned, there  are  also  two  others  situated  in  the 
optic  lobes  ( o)?  or  bigeminal  bodies,  each  of 
which,  when  laid  open,  is  seen  to  be  occupied 
by  a  convex  body  (p)  projecting  from  the 
posterior  and  internal  side  of  the  lobe;  these 
ventricles  communicate  with  the  others  in  the 
aqueduct  of  Sylvius. 

As  there  is  no  transverse  furrow  in  the  optic 
lobes,  they  cannot  be  distinguished  into  the 
protuberances  called  *  nates '  and  '  testes  '  in 


*  Anat.    Comparee,   uouv.  cd.    i.  p. 
fig.  6. 


pi.  xv. 


300 


AVES. 


the  human  brain  ;  they  have  most  resemblance, 
however,  to  the  latter  bodies. 

With  respect  to  the  substance  of  which  the 
brain  of  birds  is  composed,  we  may  observe 
that  the  bodies  analogous  to  the  corpora  striata 
do  not  merit  that  name,  as  there  are  no  alterna- 
ting striae  of  grey  and  white  matter.  In  this 
respect  the  bird's  brain  resembles  that  of  the 
cold-blooded  ovipara  and  of  the  human  fetus. 
The  substance  of  the  cerebellum  does  present 
the  admixture  of  the  two  substances,  or  arbor 
vita  (q),  but  in  a  less  complicated  degree  than 
in  mammalia. 

The  brain  in  birds  is  invested  with  the  same 
membranes  as  are  described  in  Mammalia. 

Medulla  spinalis. — The  spinal  cord  is  con- 
tinued from  the  foramen  magnum  to  the  canal 
formed  by  the  coccygeal  vertebrae,  where,  how- 
ever, it  becomes  extremely  attenuated,  and 
corresponds  in  extent  to  the  shortness  of  that 
division  of  the  vertebral  column,  terminating 
in  a  mere  filament  which  expends  itself  in 
distributing  a  few  pairs  of  nerves  through  the 
coccygeal  foramina.  As  in  the  Mammalia,  it 
appears  externally  to  be  composed  of  the  white 
or  medullary  matter,  but  contains  a  small  pro- 
portion of  grey  substance  internally.  It  is  of 
a  cylindrical  figure,  and  as  in  the  cold-blooded 
ovipara,  it  is  of  great  length  in  proportion  to 
the  brain.  An  anterior  and  posterior  fissure 
may  be  distinguished,  and  also  a  narrow  canal 
which  extends  through  its  entire  length.  Two 
enlargements  occur  in  the  course  of  the  spinal 
cord,  one  corresponding  to  the  wings,  the 
other  to  the  legs ;  and  from  these  swellings 
the  nerves  of  the  brachial  and  sacral  plexuses 
come  off  respectively.  As  might  be  expected, 
therefore,  these  enlargements  present  differ- 
ences of  relative  size  corresponding  to  the  dif- 
ferent relative  development  and  powers  of  the 
anterior  and  posterior  extremities.  In  general 
the  posterior  enlargement  is  greater  than  the 
anterior;  and  this  difference  is  very  remarkable 
in  the  Struthious  birds  in  which  the  whole 
business  of  progression  falls  upon  the  posterior 
extremities. 

Besides  the  difference  in  size,  the  spinal 
enlargements  or  ganglions,  as  they  may  be 
termed,  differ  also  in  structure ;  at  the  anterior, 
alar,  or  thoracic  enlargement  (r,  Jig.  134)  the 
spinal  cord  merely  receives  an  accession  of 
grey  and  white  medullary  substance ;  but  at 
the  beginning  of  the  sacral  swelling  (s,fg.  134) 
the  canal  of  the  cord  enlarges  in  a  remark- 
able manner,  so  that  the  lateral  cords  separate 
from  one  another  posteriorly  or  above,  pre- 
cisely as  they  do  to  form  the  fourth  cerebral 
ventricle:  the  cavity  or  spinal  ventricle  (s, 
Jig.  134)  thus  formed,  is  filled  with  a  serous 
fluid  inclosed  in  a  pia  mater.  From  the  figure 
of  this  cavity  it  has  been  termed  the  '  Sinus 
rhomboidalisJ 

Of  the  Nerves. — The  cerebral  nerves  cor- 
respond in  number  to  those  of  the  Mammalia. 
The  principal  difference  of  form  and  structure 
is  presented  in  the  olfactory  or  first  pair 
(1,  jig.  135.)  These  nerves  are  of  a  cylin- 
drical figure  and  sihall  extent,  being  continued 
from  the  anterior  extremity  or  apex  of  the 


hemispheres.  Instead  of  separating  into  fila- 
ments to  pass  out  of  the  skull  by  a  cribriform 
lamella,  each  nerve  is  continued  along  an 
osseous  canal,  accompanied  by  a  venous  trunk, 
as  far  as  the  pituitary  membrane  of  the  supe- 
rior spongy  bone  upon  which  its  filaments  are 
distributed  in  a  radiated  manner. 

The  optic  nerves  (2,  Jigs.  135, 137,)  are  in 
general  of  remarkable  size  ;  they  arise  from  the 
whole  of  the  outer  surface  of  the  optic  lobes, 
and  form  in  front  of  the  infundibulum,  a  perfect 
union,  or  chiasma,  (2*,  Jig.  137,)  in  which,  on 
making  a  horizontal  section,  some  transverse 
striae  may  be  perceived,  apparently  resulting 
from  the  decussating  fibrils  of  the  nerves. 

The  distribution  of  the  third,  (3,  Jigs.  135, 
137,)  fourth,  (4,  Jigs.  135,  137,)  and  sixth 
cerebral  nerves,  (6,  Jigs.  135,  137,)  is  almost 
the  same  as  in  Mammalia.  The  course  of  the 
fourth  pair,  immediately  above  the  supra- 
orbital  branch  of  the  fifth  pair  is  shown  at 
4*,  j0g.  137,  as  far  as  its  termination  in  the 
superior  oblique  muscle  to  which  it  is,  as  in 
other  vertebrata,  exclusively  distributed. 

The  Ji/'t h  or  trigeminal  nerve  (5,  Jigs.  \  35, 
137)  has  nearly  the  same  distribution  as  in 
Mammalia. 

The  first  or  ophthalmic  division  (5*, .fig-  137) 
passes  out  of  the  cranium  by  a  peculiar  canal 
situated  externally  to  the  optic  foramen.  It  is  of 
large  size,  and  describes  in  its  passage  through 
the  orbit  a  curve  corresponding  to  the  roof  of 
that  cavity;  it  generally  penetrates  the  substance 
of  the  facial  bones  above  the  nasal  fossae.  It 
divides  into  three  branches  ;  the  first  or  supe- 
rior is  the  smallest  and  is  lost  upon  the  pitui- 
tary membrane;  the  second  branch  is  the 
largest  of  the  three  and  the  longest ;  it  is  re- 
ceived into  an  osseous  canal,  passes  over  the 
nasal  organs,  and  terminates  at  the  extremity 
of  the  beak  in  a  great  number  of  divisions ; 
the  third  branch  of  the  ophthalmic  nerve  is 
entirely  distributed  to  the  skin  which  covers 
the  circumference  of  the  external  nostrils. 

The  second  division,  or  superior  maxillary 
nerve  passes  out  of  the  same  foramen  as  the  in- 
ferior one  (at  5",  Jig.  137,)  immediately  above 
the  tympanic  bone  or  os  quadratum  ;  it  passes 
forwards  along  the  floor  of  the  orbit,  and  in 
this  part  of  its  course  gives  off  two  filaments, 
of  which  one  joins  the  ramifications  of  the 
ophthalmic  nerve,  the  other  ascends,  penetrates 
the  substance  of  the  pterygoid  muscles  and 
the  maxillary  bone,  to  be  lost  on  the  lateral 
parts  of  the  bill.  In  those  birds,  as  the 
AnatidtE  and  other  Water- fowl,  where  the  upper 
mandible  is  notched  on  the  edge,  each  denticu- 
lation  receives  four  or  five  nervous  filaments, 
and  the  nerve  is  proportionally  of  large  size. 

The  inferior  maxillary  nerve  separates  from 
the  superior,  and  proceeds  obliquely  down- 
wards, dispensing  branches  to  the  pterygoid 
and  quadrangular  muscles  of  the  jaws;  the 
trunk  proceeds  outwards  to  the  lower  jaw 
where  it  divides  into  two  branches  an  internal 
and  an  external.  The  internal,  which  is  a  con- 
tinuation of  the  trunk,  penetrates  the  maxillary 
canal,  and  is  continued  to  the  anterior  end  of 
that  mandible.  In  the  Anatute  it  gives  off 


nerv 


AVES. 


301 


es  to  the  dentations  along  the  edge  of  the 
mandible.  The  external  branch  recedes  from 
the  internal,  perforates  the  jaw,  and  is  dis- 
tributed on  its  external  surface  beneath  the 
tegumentary  or  horny  substance  which  sheaths 
the  extremity  of  the  mandible.  It  supplies  no 
gustatory  branch  to  the  tongue,  which  is  an  or- 
gan of  prehension,  not  of  taste,  in  Birds. 

The  facial  nerve,  or  portio  dura,  exists  in 
Birds,  but  it  is  extremely  small,  its  offices 
being  hardly  required,  in  consequence  of  the 
structure  of  the  parts  of  the  face  in  this  class. 
However,  a  few  branches  may,  with  difficulty 
indeed,  be  traced,  and  the  trunk  of  the  nerve  is 
constantly  present. 

The  auditory  nerve,  or  portio  mollis,  is  large, 
very  soft  and  pulpy,  and  of  reddish  colour ; 
it  is  received  into  a  deep  depression  on  the 
internal  surface  of  the  cranium  (at  7,  fig.  137), 
whence  it  penetrates  by  several  small  foramina 
to  the  labyrinth. 

The  pneumogastric  nerve,  or  nervus  vagus, 
generally  passes  out  of  the  cranium  in  two  or 
three  filaments,  which  afterwards  rejoin.  On 
leaving  the  skull,  this  nerve  communicates 
with  the  lingual  and  glosso-pharyngeal  nerves, 
and  is  situated  between  them,  the  lingual  being 
placed  in  front.  Each  nerve  of  the  par  vagum 
passes  as  a  distinct  strong  cord  along  the  neck 
in  company  with  the  jugular  vein,  and  de- 
scending into  the  chest  forms  the  cardiac  and 
pulmonary  plexuses,  as  in  Mammalia.  The 
two  nerves  unite  behind  the  hearl,  and  proceed 
along  the  oesophagus  to  terminate  in  anasto- 
moses with  the  great  sympathetic  nerve. 

The  gtosso-pharyngeal  nerve  of  the  eighth 
pair  passes  out  of  the  cranium  through  the 
foramen  behind  the  ear,  which  corresponds  to 
the  foramen  lacerum  posterius,  by  two  filaments, 
which  immediately  unite  to  form  an  elongated 
quadrangular  ganglion  ;  this  sends  off  a  small 
internal  branch  in  front  of  the  muscles  of  the 
neck  ;  a  small  posterior  twig  which  unites  with 
the  par  vagum,  and  a  large  inferior  branch  to 
the  anterior  part  of  the  neck.  The  latter  is  a 
continuation  of  the  nerve  itself;  it  descends 
along  the  oesophagus  and  divides  into  two  prin- 
cipal branches,  of  which  one  passes  upwards 
to  the  muscles  of  the  os  hyoides,  between 
which  it  is  included,  and  this  branch  is  re- 
markably tortuous  in  the  Woodpecker  in  order 
to  be  accommodated  to  the  extensile  motions  of 
the  tongue.  The  other  branch  descends  along 
the  lateral  parieles  of  the  oesophagus,  and 
sends  off  a  twig  to  join  the  lingual  nerve. 
The  termination  of  the  glosso-pharyngeal  is 
expanded  upon  the  oesophagus. 

The  hypoglossal  nerve  (9th  pair)  escapes 
from  the  cranium  posterior  to  the  nervus  vagus 
by  the  condyloid  foramen.  It  is  very  slender 
at  its  origin;  passes  to  the  front  of  the  nervus 
vagus,  partly  uniting  with,  as  it  crosses  over  this 
nerve,  and  in  that  situation  it  detaches  a  small 
filament  analogous  to  the  descendens  noni, 
which  accompanies  the  jugular  vein  to  the 
chest.  The  trunk  of  the  hypoglossal  next 
crosses  the  glosso-pharyngeal  nerve,  then  passes 
beneath  the  cornu  of  the  os  hyoides,  and  ad- 
vances towards  the  superior  larynx,  where  it 


terminates  by  dividing  into  two  principal 
branches,  which  are  distributed,  the  one  to  the 
anterior  and  inferior,  the  other  to  the  superior 
and  internal  parts,  of  the  tongue. 

Spinal  nerves, — These  correspond  in  number 
to  the  vertebra-  of  the  spine.  They  arise,  as  in 
the  other  vertebrata  by  two  roots,  the  ganglion 
on  the  posterior  of  which  is  proportionally  very 
large.  In  the  sacral  region  of  the  spine,  the 
anterior  and  posterior  roots  escape  by  distinct 
foramina,  and  can  be  separately  divided  with- 
out laying  open  the  bony  canal,  but  they  are 
deeply  seated  and  well  protected  by  the  anchy- 
losed  processes  of  the  sacrum  and  the  extended 
iliac  bones. 

The  cervical  nerves  vary  considerably  in 
number,  the  known  extremes  being  from  ten 
to  twenty-three,  corresponding  to  the  number  of 
vertebrae.  They  are  proportionally  larger  than  in 
man,  are  tortuous  in  their  course,  to  be  accom- 
modated to  the  extensive  motions  of  the  neck, 
and  are  principally  lost  in  the  integument. 
Only  the  last,  or  last  two,  pairs  (u'  u",  fig.  134^) 
of  cervical  nerves  concur  in  the  formation  of 
the  brachial  plexus,  which  is  completed  by  the 
first  two  pairs  of  dorsal  or  thoracic  nerves  ( v). 

The  dorsal  nerves  do  not  present  any  notable 
differences  from  those  of  mammalia. 

The  sacral  nerves  have  no  other  peculiarity 
than  their  mode  of  passing  out  of  the  spinal 
canal:  they  form  exclusively  the  plexus  ana- 
logous to  the  lumbar  and  sacral  (w,Jlg.  134). 

The  nerve  analogous  to  the  phrenic  nerve  is 
wanting  in  Birds,  in  correspondence  with  the 
rudimentary  condition  of  the  diaphragm. 

The  brachial  plexus,  formed  by  the  two  last 
cervical  and  one  or  two  first  dorsal  nerves,  soon 
becomes  blended  into  a  single  fasciculus  whence 
all  the  nerves  of  the  wing  are  derived.  Accord- 
ing to  Cuvier,  the  first  four  that  are  given  off 
are  of  large  size,  and  are  distributed  to  the 
great  and  middle  pectoral  and  subclavian  mus- 
cles. A  small  filament  is  then  detached  which 
supplies  the  muscles  surrounding  the  head  of 
the  humerus  and  capsule  of  the  joint ;  this  re- 
presents the  articular  nerve.  The  rest  of  the 
plexus  divides  into  two  large  nerves,  which 
supply  the  wing. 

Macartney  describes  the  course  of  the  nerves 
of  the  wing  in  a  somewhat  different  manner, 
and  observes  that  they  more  nearly  resemble 
those  of  the  superior  extremity  in  mammalia, 
than  Cuvier  has  represented.  The  brachial 
plexus,  according  to  this  author,  gives  rise  to 
three  nerves  which  are  distributed  in  the  follow- 
ing manner : — "  The  first  is  a  very  fine  filament, 
which  runs  down  on  the  inside  of  the  arm,  and 
is  lost  about  the  internal  part  of  the  elbow. 
This  is  analogous  to  the  internal  cutaneous 
nerve.  The  second  is  a  large  cord  ;  it  gives 
off  a  very  large  branch,  which  divides  into 
many  others,  for  the  supply  of  the  pectoral 
muscles  ;  it  sends  several  smaller  branches  to 
the  muscles  under  the  clavicle  and  about  the 
joint,  and  then  proceeds  to  the  inner  edge  of 
the  biceps  muscle,  along  which  it  descends  to 
the  fold  of  the  arm,  after  giving  some  large 
muscular  branches.  Before  it  reaches  the 
joint,  it  divides  into  two  branches;  one  of 


302 


AVES. 


which  is  analogous  to  the  ulnar  nerve,  and  the 
other  soon  divides  again  into  nerves  which  are 
similar  to  the  median  and  musculo-cutaneous. 
The  median  dips  down  amongst  the  muscles  on 
the  middle  of  the  fore-arm,  to  which  it  gives 
branches,  and  afterwards  runs  along  the  inter- 
osseous  space,  passes  under  the  annular  ligament 
of  the  carpus,  and  is  distributed  to  the  short 
muscles  of  the  digiti.  The  branch  analogous  to 
the  musculo-cutaneous  nerve,  is  expanded  upon 
the  muscles  on  the  upper  edge  of  the  radius. 

11  The  ulnar  nerve,  although  it  appears  to  be 
incorporated  with  the  median  on  the  upper  arm, 
can  be  easily  separated  from  it,  and  traced  to  its 
proper  origin  in  the  brachial  plexus.  After  this 
nerve  leaves  the  median,  it  turns  over  the  end 
of  the  foramen  to  get  upon  the  edge  of  the 
ulna.  It  gives  filaments  to  the  muscles  in  this 
situation;  but  its  chief  branch  runs  down 
superficially  upon  the  ligaments  of  the  quills  in 
company  with  a  vein,  and  goes  ultimately  to 
be  lost  upon  the  ulnar  edge  of  the  hand. 

"  The  third  cord  furnished  by  the  brachial 
plexus,  supplies  the  place  of  the  radial  nerve. 
It  detaches  several  filaments  to  the  muscles  on 
the  inside  and  back  of  the  scapula.  It  gives 
off  also  the  articular  nerve,  and  then  winds 
round  the  humerus  between  the  extensor  mus- 
cles, to  which  it  furnishes  some  large  filaments. 
On  coming  to  the  outside  of  the  humerus,  it 
sends  a  branch  between  the  integuments  of  the 
fold  of  the  wing.  The  nerve  now  turns  round 
the  neck  of  the  radius,  beneath  the  muscles, 
and  forms  two  branches  ;  of  which  one  passes 
under  the  muscles  to  the  outer  side  of  the  ulna, 
along  which  it  runs  superficially  to  the  hand  ; 
the  other  branch  passes  on  the  radial  side,  but 
more  deeply  amongst  the  muscles,  goes  under 
the  annular  ligament  of  the  carpus,  proceeds 
between  the  branches  of  the  metacarpus,  and  is 
finally  lost  on  the  back  of  the  digiti."  The  same 
anatomist  describes  the  course  of  the  nerves  of  the 
posterior  extremities  as  follows. 

"  Although  Cuvier  has  given  a  more  accurate 
description  of  the  nerves  of  the  lower  extremity 
than  those  of  the  wing,  it  nevertheless  needs 
correction  in  several  particulars. 

"  The  obturator  and  femoral  nerves  arise 
from  the  same  plexus  which  is  formed  by  the 
two  last  lumbar  nerves,  by  a  communicating 
branch  from  the  first  sacral  pair.  The  obtu- 
rator nerve  passes  through  the  upper  part  of  the 
foramen  ovale,  and  is  distributed  to  the  muscles 
around  the  hip-joint,  especially  the  adductor. 
The  femoral  nerve  passes  out  of  the  pelvis  in 
company  with  the  artery,  over  the  upper  edge 
of  the  ilium.  It  divides  into  three  branches, 
which  are  dispersed  among  the  muscles  and 
integuments  on  the  anterior  and  inner  part  of 
the  thigh.  Some  of  these  filaments  are  long, 
and  descend  superficially  for  a  considerable 
way  upon  the  limb. 

"  The  ischiatic  nerve  is  composed  of  the  five 
superior  sacral  nerves ;  and  as  soon  as  it  de- 
parts from  the  plexus,  even  within  the  pelvis, 
is  easily  separable  into  its  primary  branches. 
Immediately  after  it  passes  through  the  ischi- 
adic  foramen,  it  sends  filaments  to  the  muscles 
on  the  outer  part  of  the  thigh ;  it  then  proceeds 


under  the  biceps  muscle,  along  the  back  of  the 
thigh,  about  the  middle  of  which  it  becomes 
divided  into  the  tibiul  and  the  peroneal  nerves. 

"  The  tibial  nerve,  even  before  it  arrives  in 
the  ham,  separates  into  several  branches,  which 
pass  on  each  side  of  the  bloodvessels,  and  are 
chiefly  distributed  to  the  muscles  on  the  back 
of  the  leg.  Two  of  these  branches,  however, 
are  differently  disposed  of;  the  one  accom- 
panies the  posterior  tibial  artery  down  the  leg, 
passes  over  the  internal  part  of  the  pulley,  and 
is  lost  in  small  filaments  and  anastomoses,  with 
a  branch  of  the  peroneal  nerve  on  the  inner  side 
of  the  metatarsus ;  the  other  branch  runs  down 
on  the  peroneal  side  of  the  leg,  along  the  deep- 
seated  flexors  of  the  toes,  passes  in  a  sheath 
formed  for  it  on  the  outer  edge  of  the  moveable 
pulley  of  the  heel,  and  proceeds  under  the 
flexor  tendons  along  the  metatarsal  bone,  to  be 
distributed  to  the  internal  part  of  the  two  ex- 
ternal toes. 

"  The  peroneal  nerve  is  directed  to  the  outer 
part  of  the  leg ;  it  dips  above  the  gastrocnemii 
muscles,  and  runs  through  the  same  liga- 
mentous  pulley  that  transmits  the  tendon  of  the 
biceps  muscle;  it  then  detaches  some  large 
filaments  to  the  muscles  on  the  anterior  part 
of  the  leg,  under  which  it  divides  into  two 
branches,  which  proceed  close  together,  in  com- 
pany with  the  anterior  tibial  artery  to  the  fore 
part  of  the  ankle-joint,  at  which  place  they 
separate ;  one  passes  superficially  over  the 
outer  part  of  the  joint,  the  other  goes  first 
under  the  transverse  ligament  which  binds 
down  the  tendon  of  the  tibialis  anticus  muscle 
on  the  tibia,  and  then  over  the  inner  part  of  the 
joint,  below  which  it  divides  into  two  branches, 
the  one  is  distributed  to  the  inner  side  of  the 
metatarsus  and  the  tibial  side  of  the  pollex, 
and  to  the  next  toe ;  the  other  turns  towards 
the  centre  of  the  metatarsal  bone,  and  pene- 
trates the  tendon  of  the  tibialis  anticus  just 
at  its  insertion,  and  then  rejoins  the  branch 
of  the  peroneal  nerve  it  accompanied  down  the 
leg.  They  continue'their  course  together  again 
in  the  anterior  furrow  of  the  metatarsal  bone ; 
and  at  the  root  of  the  toes,  separate  once  more, 
and  proceed  to  the  interspaces  of  the  three 
anterior  toes,  and  each  divides  into  two  fila- 
ments, which  run  along  the  sides  of  the  toes  to 
the  nail." — Rees'  Cyclopedia,  Art.  Birds. 

The  great  sympathetic  nerve  of  birds  resem- 
bles, in  many  particulars,  that  of  mammals. 
It  enters  the  cranium  by  the  same  orifice  as 
that  by  which  the  nervus  vagus  and  the  glosso- 
pharyngeal  make  their  exit;  it  there  unites 
with  the  fifth  and  sixth  pair  of  nerves.  At  the 
base  of  the  cranium  the  first  ganglion,  or  su- 
perior cervical,  is  of  a  lenticular  form,  and 
communicates  at  once  with  the  ninth  and  eighth 
pairs  of  nerves,  so  as  to  seem  as  if  it  were 
blended  with  them.  The  remainder  of  the 
chain  of  cervical  ganglions  are  very  remarkably 
situated,  being  lodged  on  either  side  in  the 
canal  of  the  vertebral  artery  formed  by  the  trans- 
verse processes ;  into  which  it  passes,  or  from 
which  it  escapes  above,  at  the  third  cervical 
vertebra,  while  below  the  sympathetic  again 
becomes  conspicuous  at  the  commencement  of 


the  thorax,  where  it  sends  a  considerable  branch 
from  the  first  thoracic  ganglion  to  join  the  pul- 
monary plexus  formed  by  the  par  vagum. 
This  ganglion  also  distributes  seven  other  fila- 
ments, one  of  which  goes  to  join  the  brachial 
plexus;  a  second  is  lost  in  the  cardiac  plexus  of 
the  par  vagum  ;  three  other  filaments  proceed 
inwardly  to  the  projection  formed  by  the  bodies 
of  the  vertebrae  to  produce  the  commencement 
of  the  splanchnic  nerve ;  lastly,  the  sixth  and 
seventh  serve  to  unite  the  first  ganglion  with 
the  second,  one  passing  above,  the  other  below 
the  head  of  die  rib,  which  they  thus  include  in 
a  lozenge-shaped  space.  Each  of  the  succeed- 
ing ganglions  forms,  in  like  manner,  a  centre  of 
nervous  radiations,  which  are  five,  six,  or  seven 
in  number,  of  which  four,  two  anterior  and  two 
posterior,  serve  to  bring  the  contiguous  ganglia 
into  communication  with  each  other;  one  or 
two  contribute  to  the  formation  of  the  splanch- 
nic nerve,  and  one  joins  the  dorsal  spinal  nerve 
situated  immediately  behind  the  ganglion. 

The  splanchnic  nerves,  formed  by  all  the  in- 
ternal thoracic  branches  of  the  great  intercostal, 
accompany  on  either  side  the  trunk  of  the 
aorta.  When  it  has  arrived  at  the  cceliac  axis, 
they  surround  it  and  form  one,  two,  or  three 
ganglions  from  which  an  immense  number  of 
filaments  are  thrown  off,  which  surround  the 
different  arteries  of  the  abdomen.  These  gang- 
lions are  evidently  the  analogues  of  the  semi- 
lunar  ganglions  of  man,  and  the  filaments  pro- 
ceeding from  them  correspond  to  the  solar 
plexus.  The  trunk  of  the  sympathetic  con- 
tinues along  the  bodies  of  the  vertebrae,  but 
the  ganglions  become  less  marked  after  the  ribs 
cease  to  be  given  off;  two  or  three  filaments 
are  given  off  from  each  of  these  small  swell- 
ings, which,  by  uniting  with  the  filaments  of 
the  opposite  side,  form  a  plexus  around  the 
aorta.  The  termination  of  the  sympathetic  may 
be  readily  traced  along  the  coccyx,  where  four 
pairs  of  ganglions  are  observable  in  the  Swan, 
the  last  of  which  join  to  form  a  ganglion  impar. 


Fig.  137. 


Cerebral  nerves,  eyes,  Sfc.  in  situ  of  a  Goose. 


303 

Organs  of  Vision. — The  eye  in  Birds  pre- 
sents many  peculiarities,  which  chiefly  relate  to 
the  extraordinary  powers  of  locomotion  in  this 
class,  tending  to  accommodate  vision  to  a  rapid 
change  of  distance  in  the  objects  viewed,  and 
to  facilitate  their  distinct  perception  through  a 
rare  medium. 

There  is  no  species  of  bird  in  which  the  eyes 
are  wanting,  or  are  rudimentary,  as  occurs  in 
the  other  vertebrate  classes. 

The  eyes  of  Birds  are,  in  the  first  place,  re- 
markable for  their  great  size,  both  as  compared 
with  the  brain  and  with  the  entire  head,  (jig. 
137,)  being  analogous,  in  this  respect,  to  the 
eyes  of  some  of  the  flying  insects.  Their  form 
is  admirably  adapted  to  promote  the  objects 
above  named.  The  anterior  segment  of  the 
eye  is  more  prominent  than  in  any  other  class 
of  animals,  and  is  in  many  birds  prolonged  into 
a  tubular  form,  terminated  by  a  very  convex 
cornea  (e,Jig.  137.)  Dr.  Macartney  observes 
that  "  the  owl  furnishes  the  most  striking  ex- 
ample of  the  disproportion  between  the  anterior 
and  posterior  spheres  of  the  eye,  the  axis  of  the 
anterior  portion  being  twice  as  great  as  that  of 
the  other.  The  obvious  consequence  of  this 
figure  of  the  globe  of  the  eye  is  to  allow  room 
for  a  greater  proportion  of  aqueous  fluid,  and 
for  the  removal  of  the  chrystalline  lens  from  the 
seat  of  the  sensation,  and  thus  produce  a  greater 
convergence  of  the  rays  of  light,  by  which  the 
animal  is  enabled  to  discern  the  objects  placed 
near  it,  and  to  see  with  a  weaker  light;  and 
hence  owls,  which  require  this  sort  of  vision  so 
much,  possess  the  structure  fitted  to  effect  it  in 
so  remarkable  a  degree." 

The  anterior  division  of  the  eye  is  least  con- 
vex in  the  swimming  birds.  The  sclerotic 
coat  is  divisible  into  three  layers.  It  is  thin, 
flexible,  and  somewhat  elastic  posteriorly,  where 
it  presents  a  bluish  shining  appearance,  without 
any  distinct  fibres,but  anteriorly  its  form  is  main- 
tained by  a  circle  of  osseous  plates  or  scales  (J\ 
fg.l  37)  interposed  between  the  exterior  and  mid- 
dle layers.  These  plates  vary  from  thirteen  to 
twenty  in  number,  and  are  situated  immedi- 
ately behind  the  cornea,  with  their  edges  over- 
lapping each  other.  They  are  in  general  thin, 
and  of  an  oblong  quadrate  figure,  becoming 
elongated  from  before  backwards  in  proportion 
as  the  bird  possesses  the  power  of  changing  the 
convexity  of  the  cornea.  In  the  nocturnal 
Raptores  the  bony  plates  are  strong  and  thick, 
and  extend  from  the  cornea  over  the  whole  of 
the  anterior  projecting  division  of  the  eye  to  the 
posterior  hemisphere,  which  they  also  contri- 
bute to  form.  The  figure  of  the  eye  is  thus 
maintained,  notwithstanding  its  want  of  sphe- 
ricity; and  in  other  classes,  as  Reptiles  and 
Fishes,  where  the  eye  recedes  from  the  spherical 
figure  from  an  opposite  cause,  viz.  the  extreme 
flattening  of  the  cornea,  that  form  is  also  pre- 
served by  the  introduction  of  an  osseous  struc- 
ture in  the  sclerotic. 

The  bony  plates  are  capable  of  a  degree  of 
motion  upon  each  other,  which  is,  however, 
restrained  within  certain  limits  by  the  attach- 
ments of  their  anterior  and  posterior  edges  to 
the  sclerotic  coat ;  and  by  their  being  bound 


304 


AVES. 


together  with  a  tough  ligamentous  substance, 
which  seems  to  be  the  continuation  of  the  scle- 
rotic between  the  edges  that  overlap  each  other. 
The  cornea  possesses  the  same  structure  as 
in  mammalia,  but  differs  with  respect  to  form. 
When  the  posterior  part  of  the  eye  is  com- 
pressed by  the  muscles,  the  humours  are  urged 
forwards  and  distend  the  cornea ;  which,  at  that 
time,  becomes  much  more  prominent  in  most 
birds  than  it  is  ever  observed  in  mammalia ; 
and  under  such  circumstances,  the  eye  is  in  a 
state  for  perceiving  near  objects.  When  the 
muscles  are  quite  relaxed,  the  contents  of  the 
eye-ball  retire  to  the  posterior  part,  and  the 
cornea  becomes  flat  or  even  depressed  :  this  is 
the  condition  in  which  we  always  find  the  eye 
of  a  dead  bird,  but  we  can  have  no  opportunity 
of  perceiving  it  during  life.  It  is  only  prac- 
tised for  the  purpose  of  rendering  objects  visi- 
ble that  are  placed  at  an  extreme  distance. 
From  the  well-known  effects  of  form  upon  re- 
fracting media,  it  must  be  presumed,  that  the 
cornea  possesses  very  little,  if  any,  convexity, 
when  a  bird  which  is  soaring  in  the  higher  re- 
gions of  the  air,  and  invisible  to  us,  discerns  its 
prey  upon  the  earth,  and  descends  with  uner- 
ring flight  to  the  spot,  as  is  customary  with 
many  of  the  rapacious  tribe. 

The  degree  of  convexity  of  the  cornea  is  also 
changed  in  birds  by  the  action  of  muscular 
fibres  especially  appropriated  to  its  motions. 
These  were  discovered  by  Crampton  ;  are  dis- 
posed around  the  circumference  of  the  cornea, 
and  are  attached  to  its  internal  layer;  they 
draw  back  the  cornea,  in  a  manner  analogous 
to  the  action  of  the  muscles  of  the  diaphragm 
upon  its  tendinous  centre. 

The  choroid  coat  re- 
sembles in  its  structure 
that  of  mammalia;  it 
is  copiously  covered 
with  a  black  pigment, 
similar  to  that  in  the 
human  eye.  Opposite 
the  bony  circle  the 
choroid  separates  into 
two  layers;  the  exter- 
nal layer  is  the  thin- 
nest, and  adheres  at  first  firmly  to  the  sclerotica, 
after  which  it  is  produced  freely  inwards  to 
form,  or  be  continuous  with,  the  iris. 

The  iris  (e,fg.  138)  is  delicate  in  its  texture, 
which  under  the  lens  appears  composed  of  a  fine 
net-work  of  interlacing  fibres, but  it  is  remarkable 
for  the  activity  and  extent  of  its  movements, 
which  seem  in  many  birds  to  be  voluntary.  The 
contraction  and  dilatation  of  the  pupil,  inde- 
pendent of  any  change  in  the  quantity  of  light 
to  which  the  eye  is  exposed,  is  most  conspicu- 
ous and  remarkable  in  the  Parrot  tribe,  but  we 
have  observed  it  also  in  the  Cassowary  and 
some  other  birds. 

The  colour  of  the  iris  is  subject  to  many 
varieties,  which  frequently  display  great  bril- 
liancy, arid  afford  zoologists  distinguishing  spe- 
cific characters  of  birds  ;  although  these  cannot 
always  be  implicitly  relied  upon. 

The  breadth  of  the  iris  varies  in  different 
species,  but  is  greatest  in  Birds  which  take 


Fig.  138. 


their  food  in  the  gloom  of  evening,  as  the 
Owls  and  Night-jar,  in  order  that  the  pupil 
may  be  proportionally  enlarged  to  admit  as 
much  light  as  possible  to  the  retina.  Carus 
observes  that  in  the  eye  of  the  Owl  is  exhibited 
with  peculiar  distinctness  the  remarkable  dis- 
tribution of  the  ciliary  nerves  and  vessels,  which, 
running  in  the  form  of  single  trunks  between 
the  choroid  and  sclerotica,  terminate  anteriorly  in 
several  ring-shaped  plexuses  for  the  supply  of 
the  iris  and  of  the  muscular  circle  of  the  cornea. 
The  pupil  is  usually  round  :  in  the  Goose  and 
Dove  it  is  elongated  transversely,  and  in  the 
Owls  is  vertically  oval. 

The  inner  layer  of  the  choroid  is  thicker  than 
the  external,  and  is  disposed  in  numerous 
thickly  set  plicae  radiating  towards  the  anterior 
part  of  the  chrystalline  lens,  where  they  termi- 
nate in  slightly  projecting  ciliary  processes,  (d, 
Jig.  138,)  the  extremities  of  which  adhere  firmly  to 
the  capsule  of  the  chrystalline.  These  processes 
are  the  most  numerous,  close  set,  and  delicate  in 
the  Owl ;  they  are  proportionally  larger  and 
looser  in  the  Ostrich. 

The  chief  peculiarity  in  the  eye  of  the  Bird 
is  the  marsupium  or  pec  ten,  (f,Jig.  138,)  which 
is  a  plicated  vascular  membrane  analogous  in 
structure  to  the  choroid,  and  equally  blackened 
by  the  pigmentum;  situated  in  the  vitreous 
humour  anterior  to  the  retina,  and  extending 
from  the  point  where  the  optic  nerve  penetrates 
the  eye  to  a  greater  or  less  distance  forwards, 
being  in  many  birds  attached  to  the  posterior 
part  of  the  capsule  of  the  chrystalline.  As  its 
posterior  point  of  attachment  is  not  to  the 
choroid  but  to  the  termination  of  the  optic 
nerve,  this  requires  to  be  first  described. 

When  the  optic  nerve  arrives  at  the  sclerotic, 
it  tapers  into  a  long  conical  extremity,  which 
glides  into  a  sheath  of  a  corresponding  figure, 
excavated  in  the  substance  of  that  membrane, 
and  directed  downwards  and  obliquely  forwards. 
The  central  or  inner  layer  of  this  sheath  is  split 
longitudinally,  and  the  substance  of  the  nerves 
passes  through  this  fissure.  A  similar  but 
longer  fissure  exists  in  the  corresponding  part 
of  the  choroid  :  so  that  the  extremity  of  the 
optic  nerve  presents  in  the  interior  of  the  eye, 
instead  of  a  round  disc,  as  in  mammalia,  a 
white  narrow  streak,  from  the  extremities  and 
sides  of  which  the  retina  is  continued.  Branches 
of  the  ophthalmic  artery,  which  are  quite  dis- 
tinct from  the  vessels  of  the  choroid,  and  ana- 
logous to  the  arteria  ccntralis  retinae,  enter  the 
eye  between  the  laminae  of  the  retina,  along  the 
whole  extent  of  the  oblique  slit  above  men- 
tioned, and  immediately  enter  or  compose  the 
folds  of  the  marsupial  membrane,  upon  which 
they  form  most  delicate  and  beautiful  arbore- 
scent ramifications. 

The  marsupium  is  lodged  like  a  wedge  in 
the  substance  of  the  vitreous  humour,  in  a 
vertical  plane,  directed  obliquely  forwards.  In 
those  species  in  which  the  marsupium  is  widest, 
the  angle  next  the  cornea  reaches  the  inferior 
edge  of  the  capsule  of  the  chrystalline ;  but 
where  it  is  narrow,  the  whole  anterior  surface 
is  in  contact  with  the  same  point.  This  con- 
tact is  so  close  in  some  birds,  as  the  Vulture, 


AVES. 


305 


Parrot,  Turkey,  Cassowary,  Stork,  Goose,  and 
Swan,  that  the  rnarsupium  seems  absolutely  to 
adhere  to  the  capsule  of  the  lens ;  but  in  many 
other  birds,  on  the  contrary,  it  does  not  extend 
further  than  two  thirds  of  the  distance  from 
the  back  part  of  the  eye,  and  is  attached  at  its 
anterior  extremity  to  some  of  the  numerous 
laminae  of  the  hyaloid  membrane  which  form 
the  cells  for  the  lodgment  of  the  vitreous  hu- 
mour. In  these  cases  the  marsupium  can 
have  no  influence  on  the  movements  of  the 
lens,  unless  it  be  endowed  with  an  erectile 
property,  and  be  so  far  extended  as  to  push 
forward  the  lens.  The  researches  of  Bauer* 
have  shewn  that  there  is  no  muscular  structure 
in  the  marsupium,  and  its  changes  of  form, 
if  such  occur  in  the  living  bird,  must  be 
effected  by  changes  in  the  condition  of  the 
vessels  of  which  it  is  almost  exclusively  com- 
posed. 

The  form  of  the  marsupium  varies  in  differ- 
ent birds ;  it  is  broader  than  it  is  long  in  the 
Stork,  Heron,  Turkey,  and  Swan ;  and  of  the 
contrary  dimensions  in  the  Owl,  Ostrich,  and 
Cassowary.  The  plicae  of  the  membrane  are 
perpendicular  to  the  terminal  line  of  the  optic 
nerve ;  they  are  of  a  rounded  figure  in  most 
species,  but  in  the  Ostrich  and  Cassowary  they 
are  compressed,  and  so  far  inclined  from  the 
plane  of  the  membrane,  that  their  convergence 
towards  its  extremity  gives  it  a  resemblance  to  a 
close-drawn  purse.f  The  folds  vary  in  num- 
ber, being  four  in  the  Cassowary,  seven  in  the 
Great  Horned  Owl,  eight  in  the  Goose,  from 
ten  to  twelve  in  the  Duck  and  Vulture,  fifteen 
in  the  Ostrich,  sixteen  in  the  Stork,  and  still 
more  numerous  in  the  Insessorial  Birds, 
amounting  to  twenty-eight,  according  toSoem- 
merring,  in  the  Fieldfare. 

The  exact  functions  of  the  marsupial  mem- 
brane are  still  involved  in  obscurity.  Its  po- 
sition is  such  that  some  of  the  rays  of  light 
proceeding  from  objects  laterally  situated  with 
respect  to  the  eye  must  fall  upon  and  be 
absorbed  by  it ;  and  Petit  accordingly  supposed 
that  it  contributed  to  render  more  distinct  the 
perception  of  objects  placed  in  front  of  the  eye. 
The  theory  originally  proposed  by  Sir  Everard 
IIome,t  which  attributed  to  the  marsupium  the 
office  of  retracting  the  lens  for  the  purpose  of 
distant  vision  by  its  muscular  contraction,  is 
opposed  by  the  numerous  examples  in  which 


*   Philosophical  Transactions,  1822,  p.  76. 

t  The  Parisian  Academicians,  who  took  their  de- 
scription of  this  part  from  the  Ostrich,  first  applied 
to  it  the  name  of  Ufarsupium  or  Bourse.  The  origi- 
nal description  is  as  follows  : — "  De  cet  entonnoir 
(the  termination  of  the  optic  nerve)  sortoit  une 
membrane  p\issceffaisant  comme  une  bourse  qui  abou- 
tissoit  en  pointe  vers  le  hord  du  Christallin  le  plus 
prochain  de  1 'entree  dn  nerf  optique.  Cette  bourse, 
qui  estoit  large  de  six  lignes  par  le  bas,  a  la  sortie 
du  nerf  optique,  et  qui  ^lloit  en  pointe  vers  le  bant, 
estoit  attachee  par  sa  pointe  an  bord  du  Chrystallin, 
par  le  moyen  de  la  membrane  qui  le  couvroit  du 
roste  de  1'humenr  vitree,  et  qui  couvroit  aussi  toute 
la  bourse  qui  estoit  noir  mais  d'un  autre  noir  que 
n'est  celuy  de  la  choroide." — Duvernoy,  in  '  Me- 
moires  pour  servir  a  1'Hist.  Nat.  des  Animaux/ 
p.  375. 

J  Croonian  Lecture,  Phil.  Trans.   1796. 

VOL.  I. 


it  does  not  extend  to  the  chrystalline,  and  by 
the  manner  of  its  attachment  in  those  cases  in 
which  it  does;  since,  as  in  these  the  mar- 
supium adheres  to  the  side  of  the  chrystalline, 
it  can  only  move  it  obliquely. 

Some  physiologists  have  supposed  that  this 
black  membrane  was  extended  towards  the  centre 
of  the  eye,  where  the  luminous  rays  are  most 
powerfully  concentrated  in  order  to  absorb  the 
excess  of  intense  light  to  which  birds  are  ex- 
posed in  soaring  aloft  against  the  blazing  sun. 
Others  have  considered  it  as  the  gland  of  the 
vitreous  humour,  and  that,  as  this  fluid  must 
be  rapidly  consumed  during  the  frequent  and 
energetic  use  made  of  the  visual  organ  by 
Birds,  it  therefore  might  require  a  superadded 
vascular  structure  for  its  reproduction. 

We  are  inclined  to  consider  the  marsupium 
as  an  erectile  organ,  adapted  to  receive  a  vary- 
ing quantity  of  blood,  and  to  occupy  a  variable 
space  in  the  vitreous  humour ;  when  fully  in- 
jected, therefore,  it  will  tend  to  push  forward 
the  lens,  either  directly  or  through  the  medium 
of  the  vitreous  humour,  which  must  be  dis- 
placed in  a  degree  corresponding  to  the  in- 
creased size  of  the  marsupium  ;  the  contrary 
effects  will  ensue  when  the  vascular  action  is 
diminished.  From  the  analogy  of  other  struc- 
tures introduced  by  Supreme  Wisdom  into  the 
mechanism  of  organized  bodies,  it  may  reason- 
ably be  supposed  that  the  marsupium  is  not 
limited  to  a  single  function. 

The  retina  is  continued  from  the  circumference 
of  the  base  of  the  marsupium,  and  after  forming 
a  few  slight  folds  expands  into  a  smooth  layer 
of  medullary  matter,  which  seems  to  terminate 
at  the  periphery  of  the  corpus  ciliare.  In  the 
Owls,  as  Haller  has  observed,  not  more  than 
half  the  globe  of  the  eye  is  lined  by  the  retina ; 
it  ceases  in  fact  where  the  eye  loses  the  sphe- 
rical form  at  the  base  of  the  anterior  cylindrical 
portion. 

The  humours  of  the  eye  no  less  correspond 
to  the  peculiar  vision  of  the  bird,  and  the  rare 
medium  through  which  it  is  destined  to  move, 
than  the  shape  of  the  globe  and  the  texture  of 
its  coats. 

The  aqueous  humour  is  extremely  abundant, 
owing  to  the  extent  of  the  anterior  chamber 
gained  by  the  convexity  of  the  cornea,  and 
its  refractive  power  must  be  considerable  in  the 
higher  regions  of  the  atmosphere.  The  mem- 
brane inclosing  it  can  be  more  readily  demon- 
strated in  birds  than  in  most  mammals,  espe- 
cially where  it  adheres  to  the  free  edge  of  the 
iris.  The  large  size  of  the  ciliary  processes 
may  have  the  same  relation  to  the  repro- 
duction of  the  aqueous,  as  the  marsupium  is 
supposed  to  have  with  reference  to  the  vitreous 
humour. 

The  chrystalline  lens  is  remarkable  for  its  flat- 
tened form,  especially  in  the  high-soaring 
Birds  of  Prey ;  it  is  also  of  a  soft  texture,  and 
is  without  any  hard  nucleus,  as  in  the  eyes 
of  Fishes  and  Reptiles.  In  the  Cormorant 
and  other  birds  which  seek  their  food  in 
water,  the  chrystalline  is  of  a  rounder  figure, 
and  this  is  peculiarly  the  case  in  the  near- 
sighted Owls  which  hunt  for  prey  in  obscure 

x 


306 


AVES. 


light.  It  is  inclosed,  as  in  Mammalia,  in  a 
distinct  capsule,  which  adheres  very  firmly  to 
the  depression  in  the  anterior  part  of  the 
vitreous  humour;  the  capsule  is  itself  lodged 
between  two  layers  of  the  membrana  hyaloidea, 
which,  as  they  recede  from  each  other  to  pass — 
t'te  one  in  front  and  the  other  behind  the  lens, 
— leave  round  its  circumference  the  sacculated 
c;inal  of  Petit. 

The  vessels  of  the  lens  are  derived  from 
those  of  the  marsupium,  which,  as  we  have 
before  observed, are  ramifications  of  the  analogue 
of  the  arteria  centralis  retina.  With  respect  to 
this  vessel  we  may  here  observe,  that  it  is  not 
continued  as  a  simple  branch  from  its  origin  to 
the  marsupium, — such  a  course  would  be  in- 
consistent with  the  important  functions  it  is 
destined  to  fulfil  in  the  present  Class.  Imme- 
diately before  penetrating  the  coats  of  the  eye 
it  breaks  into  numerous  subdivisions,  the  aggre- 
gate of  which  is  much  greater  than  the  trunk 
whence  they  proceed,  and  these  again  unite, 
forming  a  plexus  (s,fg.  139)  close  to  the  ex- 
ternal side  of  the  optic  nerve.  The  artery  of 
the  marsupium  proceeds  from  this  plexus,  and 
runs  along  the  base  of  the  folds,  giving  off  at 
right  angles  a  branch  to  each  fold,  which  in 
like  manner  sends  off  smaller  ramuli.  The 
plexus  at  the  origin  of  the  marsupial  artery 
serves  as  a  reservoir  for  supplying  the  blood 
required  for  the  occasional  full  injection  of  the 
marsupium  ;  and  a  similar  but  larger  plexus 
(4,^/iir.  139)  is  formed  at  the  origins  of  the 
ciliary  arteries  which  supply  the  erectile  tissue 
of  the  ciliary  processes  and  iris.  These  plexuses 
are  described  by  Barkow,  from  whose  Memoir* 
the  subjoined  figure  is  taken,  but  their  relation 
to  the  erectile  powers  of  the  parts  they  supply 
appears  to  have  escaped  his  notice. 

The  vitreous  humour  presents  few  peculia- 
rities worthy  of  note  ;  compared  with  the  aque- 
ous humour,  it  is  proportionally  less  in  quan- 
tity than  in  the  eyes  of  Mammalia.  The  outer 
capsule  formed  by  the  hyaloid  membrane  is 
stronger,  and  can  be  more  easily  separated 
from  the  humour. 

The  Eye-ball 
is  moved  in  Birds 
by  four  straight 
and  two  oblique 
muscles.  The 
Recti  muscles  a- 
rise  from  the  cir- 
cumference of  the 
optic  foramen  and 
expand,  as  they 
pass  forward,  to 
be  inserted  into 
the  soft  middle 
part  of  the  scle-  Muscles  of  the  eye. 

rotic.  We  have  not  been  able  to  trace  their 
insertion  distinctly  to  the  osseous  circle ; 
their  aponeurosis  cannot  be  reflected  for- 
wards from  the  sclerotica  without  lacerating 
that  membrane. 

The  Obliqui  both  arise  very  near  together 
from  the  anterior  parietes  of  the  orbit,  and  go 

*  Meckcl's  Archiven,  B.  xii,  pi.  x. 


Fig.  139. 


to  be  inserted,  the  one  into  the  upper,  the  other 
into  the  lower  part  of  the  globe  of  the  eye ;  the 
superior  obliquus  does  not  pass  through  a 
pulley,  as  in  Mammalia. 

All  the  muscles  are  proportionally  short  in 
this  class,  but  especially  so  in  the  Owls,  in 
which  the  eye,  from  its  large  size  and  close 
adaptation  to  the  orbit,  can  enjoy  but  very  little 
motion. 

In  the  subjoined  figure  and  in  fig.  140, 
«'  is  the  rectus  superior  or  attollens ;  b'  the 
rectus  inferior  or  deprimens ;  c'  the  rectus  ex- 
ternus  or  abducens ;  d'  the  rectus  interims  or 
adducens  ;  e'  the  obliquus  superior ;  f  the  ob- 
liquus  inferior  ;  g'  the  quadrat  us  ;  h'lhepyra- 
niidalis. 

The  accessory  parts  of  the  eye  in  Birds  are 
similar  to  those  of  the  higher  Reptiles.  There 
are  three  eye-lids,  two  of  which  move  vertically, 
and  have  a  horizontal  commissure,  while  the 
third,  which  is  deeper-seated,  sweeps  over  the 
eye-ball  horizontally,  from  the  inner  to  the 
outer  side  of  the  globe.  The  vertical,  or  upper 
and  lower  eye-lids,  are  composed  of  the  com- 
mon integument,  of  a  layer  of  conjunctiva,  and 
between  these  of  a  ligamentous  aponeurosis, 
which  is  continued  into  the  orbit,  and  lines  the 
whole  of  that  cavity.  The  lower  eye-lid  is  the 
one  which  generally  moves  in  closing  the  eye  in 
sleep,  and  it  is  further  strengthened  by  means 
of  a  smooth  oval  cartilaginous  plate,  which  is 
situated  between  the  ligamentous  and  con- 
junctive layers. 

The  orbicularis  muscle  is  so  disposed  as  by 
means  of  this  plate  to  act  more  powerfully  in 
raising  the  lower  than  in  depressing  the  upper 
eye-lid.  In  the  latter  it  is  continued  imme- 
diately along  the  margin :  in  the  lower  eye-lid 
the  tarsal  cartilage  intervenes  between  the  mus- 
cle and  the  ciliary  margin. 

The  levator  palpebra  sitperioris  arises  from 
the  roof  of  the  orbit,  and  is  inserted  near  the 
external  angle  of  the  lid. 

There  is  also  an  express  muscle  for  depress- 
ing the  lower  eye-lid,  as  in  the  Crocodile. 

In  the  Owls  and  Night-jar  (Caprimu/gus) 
the  eye-lids  are  closed  principally  by  the  depres- 
sion of  the  upper  one.  There  are  but  few  birds 
that  possess  eye-lashes ;  of  these  the  Ostrich  is 
an  example,  as  also  the  Horn-bills  and  the  Owls, 
in  which  they  are  arranged  in  a  double  series  ; 
but  in  these  they  are  rather  to  be  considered  as 
feathers  with  short  barbs,  than  true  eye-lashes. 

The  third  eye-lid,  or  membrana  nictitans,  is 
a  thin  membrane,  transparent  in  some  birds, 
in  others  of  a  pearly  white  colour,  which, 
when  not  in  action,  lies  folded  back  by  virtue 
of  its  own  elasticity  on  the  inner  or  nasal  side 
of  the  globe  of  the  eye,  with  which  it  is  in  close 
contact. 

Two  muscles  are  especially  provided  to  effect 
its  movements,  but  are  so  placed  as  to  cause 
no  obstruction  to  the  admission  of  light  to  the 
eye  during  their  actions.  One  of  these  is 
called  the  Quadratus  nictitantis,  (g,fig.  139;) 
it  arises  from  the  sclerotica  at  the  upper  and 
back  part  of  the  globe  of  the  eye,  and  its  fibres 
slightly  converge  as  they  descend  towards  the 
optic  nerve,  above  which  they  terminate  in  a 


AVES. 


307 


semilunar  tendinous  shenth,  having  no  express 
or  fixed  insertion.  The  second  muscle,  called 
fyramidalii  iiicfitantis,  (h,  fig.  139,)  arises 
from  the  sclerolica  from  the  lower  and 
nasal  side  of  the  eye-ball ;  its  fibres  con- 
verge as  they  pass  to  the  upper  side  of  the 
optic  nerve,  and  there  terminate  in  a  small 
round  tendon,  which  glides  through  the  pulley 
at  the  free  margin  of  the  quadrat  us,  and  wind- 
ing round  the  optic  nerve,  passes  along  a  cellu- 
lar sheath  at  the  lower  part  of  the  sclerotica, 
and  is  inserted  into  the  lower  part  of  the  mar- 
gin of  the  third  eye-lid,  along  which  it  is 
continued  for  some  distance,  and  is  gradually 
lost. 

By  the  simultaneous  action  of  the  two  mus- 
cles, the  membrana  nictitans  is  drawn  forcibly 
outwards  and  with  an  oblique  inclination  down- 
wards over  the  anterior  part  of  the  eye.*  The 
tendon  of  the  pyramidalis  gains  the  due  direc- 
tion for  that  action  by  winding  round  the  optic 
nerve,  and  it  is  restrained  from  pressing  upon 
that  nerve  during  the  action  of  the  pyramidalis 
muscle  by  the  counteracting  force  of  the  qua- 
drat us,  which  thus  augments  the  power  of  the 
antagonist  muscle,  while  it  obviates  any  incon- 
venience from  pressure  on  the  optic  nerve, 
which  its  peculiar  disposition  in  relation  to  that 
part  would  otherwise  occasion. 

To  examine  this  singular  and  beautiful  me- 
chanism, it  is  necessary  to  remove  the  muscles 
of  the  eye-ball,  especially  the  rccti. 

Lachrymal  Organs. — There  are  two  glands 
which  secrete  a  fluid  to  lubricate  the  ball  of 
the  eye,  and  facilitate  the  movements  of  the 
eye-lids  ;  one  of  these  relates  more  especially  to 
the  movements  of  the  nictitating  membrane, 
and  is  called  from  its  discoverer  the  Harderian 
Gland ;  the  other  corresponds  to  the  ordinary 
Glandula  lachrymalis. 

Fig.  140. 


*  This  oblique  motion  is  most  remarkable  in  the 
Owls,  in  which  the  nictitating  membrane  is  ac- 
companied by  the  upper  eye-lid  in  its  sweeping 
movement  across  the  eye-ball. 


The  Glanduld  Hardcriana  (i,  fig.  140) 
is  a  conglomeration  of  mucous  follicles,  which 
compensates  for  the  absence  of  Meibomian 
glands  in  Birds ;  it  is  generally  of  large  size, 
situated  at  the  internal  angle  of  the  eye, 
and  pours  out  a  thick  viscid  secretion  by  a 
small  duct  which  opens  beneath  the  nictitating 
membrane.  The  surface  of  the  gland  is  di- 
vided into  many  small  lobules,  which,  when 
injected  with  mercury,  are  seen  to  be  com- 
posed of  still  smaller  vesicles. 

It  is  interesting  to  find  that  some  of  the 
Rodentia,  which  manifest  so  many  affinities 
to  the  Class  of  Birds,  have  a  corresponding 
gland ;  in  the  Hare,  for  example,  it  is  of  large 
size  and  bipartite,  situated  at  the  internal  angle 
of  the  orbit,  and  opening  beneath  the  internal 
eye-lid. 

The  true  lachrymal  gland  is  situated  at  the 
external  angle  of  the  eye.  In  the  Goose  it  is 
of  a  flattened  form,  about  the  size  of  a  pea, 
opening  upon  the  inside  of  the  outer  angle  of 
the  eye-lids  by  a  short  and  wide  duct.  Its 
secretion  is  less  viscid  than  that  of  the  Har- 
derian gland :  but  this  is  not  uniformly  the 
case. 

The  lachrymal  duct  consists  of  a  wide  mem- 
branous canal  commencing  by  two  apertures  at 
the  nasal  canthus  of  the  eye,  and  terminating 
below  and  a  little  before  the  middle  or  great 
turbinated  cartilage.  In  the  Ostrich  there  is 
a  glandular  prominence  at  the  commencement 
of  each  of  the  lachrymal  canals ;  these  seem 
analogous  to  the  caruncula  lachrymalis.  In 
other  birds  this  structure  is  wanting. 

Nasal  gland,  (k,  Jig.  140.)—  Besides  the 
lachrymal  glands,  or  those  which  furnish  a 
fluid  for  the  purpose  of  lubricating,  defending, 
and  facilitating  the  movements  of  the  eye-ball, 
there  exists  another  gland,  which,  from  its 
position  within  or  near  the  orbit,  seems  at  first 
sight  to  appertain  to  the  preceding  series,  but 
the  secretion  of  which  is  exclusively  employed 
in  lubricating  the  pituitary  membrane  of  the 
nose.  This  gland,  which  corresponds  to  the 
nasal  glands  of  serpents,  and  those  described 
by  Jacobson*  in  Mammalia,  is  situated  in 
many  aquatic  and  marsh  birds  above  the 
supra-orbital  ridge  in  a  depression  noticed  in 
the  description  of  the  skull,  (p.  278.)  In 
most  birds  it  is  lodged  within  the  orbit  itself; 
in  some  it  is  found  under  the  nasal  bone,  or 
in  the  cavity  analogous  to  the  maxillary  sinus. 
In  the  Woodpeckers  it  is  found  in  the  sub- 
ocular  air-cell.  It  appears  to  be  present  in 
every  order  of  Aves.f 

In  the  Anserine  Birds  this  gland  is  so  situ- 
ated as  to  complete  the  superior  margin  of  the 
orbit,  f/c',  Jig.  140,)  and  is  inclosed  in  an  ex- 
tremely dense  fibrous  membrane.  Its  duct 
(/,  fig.  140)  is  long,  and  passes  to  the  nose 
along  an  osseous  groove,  behind  the  lachrymal 
bone.  Its  structure  is  simple,  like  that  of  the 
salivary  glands  in  the  same  class,  being  com- 
posed of  ramified  follicles  from  which  the 

*  Nouv.  Bullet,  des  Sc.  par  la  Soc.  Philomath, 
iii.  an  6.  p.  267. 

t   Nitzsch,  Mcckel's  Archiv.  vi.  p.  234. 

x  2 


808 


AVKS. 


acini  of  the  cells  proceed.  In  the  Albatross 
and  Penguin  we  have  traced  two  or  three 
distinct  ducts  leading  from  this  gland  to  the 
nose. 

Organ  of  Hearing. — The  structure  of  the 
organs  of  hearing  in  Birds  resembles  most  closely 
that  in  the  higher  Reptiles,  especially  the 
Crocodile.  There  is  no  concha,  or  projecting 

Fig.  141. 


Organ  of  hearing.    Owl. 

auricle  in  this  class,  for  collecting  and  con- 
densing the  rays  of  sound ;  but  to  compen- 
sate for  this  deficiency,  the  labyrinth,  and 
especially  the  semicircular  canals,  are  of  large 
size  in  proportion  to  the  cranium.  In  those 
Birds,  however,  which  enjoy  the  locomotive 
or  visual  faculties  in  a  less  perfect  degree 
than  in  the  rest  of  the  class,  there  is  found 
a  peculiar  arrangement  of  the  feathers  around 
the  external  meatus  auditorius,  which  serves 
in  some  degree  the  office  of  an  external  ear. 
The  Ostrich  and  Bustard  (d,fig.  155)  are  so 
provided,  and  these  birds  can  raise  the  auditory 
circle  of  plumes  to  catch  distinctly  any  distant 
sound  that  may  alarm  them.  The  Owls,  again, 
are  furnished  with  a  large  crescentic  mem- 
branous flap,  or  valve ;  and  the  membrana 
tympani  is  situated ^at  the  bottom  of  a  cavity 
(a,  fig.  141),  the  lining  membrane  of  which 
is  disposed  in  folds  analogous  to  those  of  the 
human  auricle.  The  opercular  flap  is  largely 
developed  in  our  common  Barn-owl  (Strix 
flammea).  This  species  is  also  remarkable  in 
having  the  membrana  tympani  attached  ex- 
clusively to  the  bony  meatus  (b,Jig.  141),  and 
not  to  the  tympanic  bone  or  os  quadratum. 

The  bony  framework  of  the  membrana  tym- 
pani is  sunk  below  the  surface  of  the  head, 
and  rarely  projects  so  far  from  the  tympanum 
as  to  deserve  the  name  of  a  meatus  or  canal : 
it  is  deficient  anteriorly,  where  it  is  bounded 
by  the  tympanic  bone,  to  which,  with  the  ex- 
ception above  mentioned,  the  membrana  tym- 
pani is  attached  for  a  greater  or  less  extent  of 
its  anterior  circumference. 

The  drum  of  the  ear  (c,  Jig.  141)  is  more 
or  less  of  an  oval  shape ;  it  has  the  same 
structure  as  in  Mammals,  but  is  extremely 
delicate ;  it  is  convex  externally,  as  in  the 
Reptiles,  not  concave,  as  in  most  Mammals. 

The  cavity  of  the  tympanum  is  widest  at  its 
outer  part,  and  very  irregular  in  the  rest  of  its 
extent.  It  communicates  by  the  usual  fora- 


mina with  the  internal  ear,  and  is  connected 
with  the  fauces  by  means  of  the  Eustachian 
tube.  It  also  communicates  by  three  other 
apertures  with  the  cells  of  the  bones  of  the 
cranium.  "  These,"  Macartney  observes,  "  are 
widened  into  something  like  canals,  where 
the  holes  open  into  them.  The  largest  of 
the  foramina  is  in  the  back  of  the  tympa- 
num, and  leads  to  the  posterior  cells,  and 
communicates  above  the  foramen  magnum 
with  the  cellular  canal  of  the  other  side.  The 
second  opening  is  placed  at  the  anterior  part 
of  the  tympanum,  and  conducts  to  the  cells  on 
the  lower  and  anterior  part  of  the  cranium. 
The  third  foramen  is  continued  amongst  the 
cells  which  surround  the  labyrinth.  Thus 
each  tympanum  has  a  communication  with 
the  interior  of  all  parts  of  the  cranium,  and 
with  each  other,  from  which  they  might  be 
reckoned  as  making  only  one  cavity.  The 
end  of  the  tympanic  bone,  also,  where  it 
contributes  to  form  the  parietes  of  the  tym- 
panum, has  a  foramen  by  which  it  derives  its 
supply  of  air.  The  auditory  cells  of  the  cra- 
nium of  birds  are  analogous  to  the  mastoid  of 
the  human  subject ;  but  from  their  extent  they 
multiply  sound  much  more.  They  are  of  the 
greatest  magnitude  in  the  nocturnal  birds  of 
prey;  the  Night-jar  (Caprimulgus)  has  them 
also  very  large  :  they  diminish  in  size  in  other 
birds,  in  which  the  posterior  canals  have  no 
direct  communication  with  each  other;  they 
are  little  observable  in  the  Struthious  Birds, 
and  are  wanting  in  the  Parrots,  but  in  their 
place  the  cavity  of  the  tympanum  is  enlarged 
posteriorly." 

The  Eustachian  tube  (e,  e,  Jig.  141)  is  very 
large  in  birds;  it  is  an  osseous  canal,  and  ter- 
minates by  a  small  aperture  close  to  the  one 
of  the  other  side,  within  the  fissure  of  the 
posterior  nares.  In  the  Swan  the  Eustachian 
passages,  after  having  reached  the  base  of 
the  skull,  pass  forwards  for  about  half  an 
inch  and  then  unite  to  form  one  common 
tube,  which  gradually  expands  until  it  termi- 
nates just  behind  the  posterior  apertures  of  the 
nose. 

The  foramina,  which  lead  from  the  tym- 
panum into  the  labyrinth,  are  situated  within 
a  fossa.  They  do  not  merit  the  distinctions  of 
foramen  ovale  and  foramen  rotundum,  being 
both  oval,  and  only' separated  by  a  small  bony 
process. 

The  ossicula  auditus  are  supplied  by  a  sin- 
gle bone,  analogous  to  the  stapes,  and  some 
cartilaginous  processes  representing  the  rudi- 
ments of  a  malleus  and  incus.  The  ossiculum 
consists  of  a  stalk  or  pedicle,  crowned  by  an 
oval  plate,  which  is  applied  to  the  foramen 
that  leads  into  the  vestibule  of  the  labyrinth. 
At  the  other  extremity  it  is  united  to  two  or 
three  cartilaginous  processes,  which  form  a  tri- 
angle that  is  attached  to  the  membrana  tym- 
pani. 

The  elongated  stapes,  or  tympanic  ossicle,  is 
moved  by  one  muscle  (f,  fig-  141),  which 
comes  from  the  occiput  and  penetrating  the 
cavity,  is  affixed  to  the  triangle  that  is  con- 
nected to  the  membrana  tympani.  This  muscle, 


AVKS. 


300 


in  consequence  of  the  connections  of  the  ossi- 
culuin,  is  a  tensor,  and  draws  the  membrana 
tympani  outwards.  It  is  counteracted  by  two 
small  tendinous  cords  that  are  extended  to  the 
internal  parietes  of  the  tympanum. 

The  labyrinth  of  the  ear  of  birds  consists 
of  the  vestibule,  the  three  semicircular  canals, 
and  the  rudiment  of  the  cochlea.  These  parts 
are  included  within  the  bones  of  the  cranium, 
which  form  a  dense  vibraiile  case  (d)  around 
the  whole  internal  ear. 

The  vestibule  is  small  in  proportion  to  the 
other  parts,  but  is  more  elongated  than  in  the 
cold-blooded  Reptilia. 

The  semicircular  canals  have  been  termed 
by  Scarpa,  from  their  gradation  in  bulk, 
caiuiles  major,  minor,  and  minimus.  The 
largest  is  most  superior,  and  has  a  vertical 
position*  (h,  fig.  141).  The  smallest  is  situ- 
ated horizontally  (k,k).  The  canalis  minor 
or  second  canal  (i)  is  vertical,  it  ascends  upon 
the  horizontal  canal,  and  opens  into  its  side 
at  m.  They  contain  corresponding  tubes  of 
vascular  membrane,  and  they  also  possess  en- 
larged ampulla,1  (/),  on  which  the  nerves  are 
distributed  in  the  same  manner  as  in  mam- 
malia. 

The  place  of  the  cochlea  is  supplied  by  a 
short  obtuse  osseous  conical  tube  (n,  fig.  141), 
as  in  the  Crocodile,  very  slightly  bent,  with 
the  concavity  directed  backwards.  Its  interior 
is  occupied  by  two  small  cylinders  of  fine  car- 
tilage, each  a  little  twisted,  and  united  by  a  thin 
membrane  at  their  origin  and  termination.  They 
proceed  from  the  osseous  bar,  which  separates 
the  two  foramina,  corresponding  to  the  foramen 
ovale  and  rotundum.  The  sulcus,  which  is  left 
between  the  cartilages,  is  dilated  near  the  point, 
and  accommodates  the  same  branch  of  the 
auditory  nerve,  which  is  sent  to  the  cochlea  in 
mammalia.  This  nerve  spreads  in  fine  fila- 
ments upon  the  united  extremity  of  the  carti- 
laginous cylinders.  The  tube  is  divided  by 
the  presence  of  the  cartilages  into  two  scala?, 
the  anterior  of  which  communicates  with  the 
vestibule  and  is  not  closed  ;  the  posterior  scala 
is  shorter,  and  communicates  with  the  tym- 
panum by  the  foramen  rotundum,  which  is 
closed  by  a  membrane.  Besides  these  parts  the 
cochlea  still  contains  a  trace  of  the  cretaceous 
substance  which  forms  so  conspicuous  a  part 
of  the  organization  of  the  internal  ear  in 
Fishes. 

The  Struthious  birds  manifest  their  close 
relation  to  the  Reptilia  by  having  the  tube 
corresponding  to  the  cochlea,  very  small  in 
proportion  to  the  other  parts. 

The  seventh  cerebral  nerve  is  received  into 
a  fossa,  and  there  divides  into  five  branches ; 
one  is  the  facial,  or  portio  dura,  and  the  others 
are  sent  to  the  semicircular  canals  and  the  tube. 
The  facial  nerve  receives  a  filament  from  the 
par  vagum,  which  traverses  the  ear,  and  is 
afterwards  distributed  to  the  palate. 

Comparetti  has  described  two  canals  leading 

*  In  the  Insessores  this  canal  is  generally  the 
smallest  of  the  three. 


from   the  labyrinth  of  birds,  which  correspond 
with  the  aqueducts  of  the  mammalia.* 

Organ  of  Smell. — The  close  affinity  subsist- 
ing between  the  cold  and  warm-blooded  ovi para 
is  no  where  more  strongly  manifested  than  in 
the  olfactory  organs.  The  external  nostrils  are 
simple  perforations,  having  no  moveable  car- 
tilages or  muscles  provided  for  dilating  or  con- 
tracting their  apertures,  as  in  mammalia.  The 
extent  of  surface  of  the  pituitary  membrane 
is  not  increased  by  any  large  accessory  cavities, 
but  simply  by  the  projections  and  folds  of  the 
turbinated  bones.  The  olfactory  nerve  is  sim- 
ple, as  in  the  Tortoise,  and  passes  out  of 
the  skull,  as  before  observed,  by  a  single  fo- 
ramen. 

The  external  nostrils  vary  remarkably  both 
in  shape  and  position,  and  serve  on  that  ac- 
count as  zoological  characters.  They  are  placed 
at  the  sides  of  the  upper  mandible  in  the 
majority  of  birds,  but  in  some  species  are 
situated  at  or  above  the  base  of  the  bill;  the 
latter  is  the  case  in  the  Toucans;  in  the  Ap- 
teryx  Australis  they  are  found  at  the  extremity 
of  the  long  upper  mandible. 

In  general  they  are  wide  and  freely  open  to 
facilitate  the  inhalation  of  air  during  the  rapid 
motions  of  the  bird,  but  sometimes  they  are 
so  narrow  that,  as  in  the  Herons,  they  will 
scarcely  admit  the  point  of  a  pin ;  and  in  ihe 
Gannet  they  have  been  supposed,  but  erro- 
neously, to  be  wanting  altogether  .f 

In  the  Rasores  the  nostrils  are  partially 
defended  by  a  scale.  In  the  Corvuta  they 
are  protected  by  a  bunch  of  stiff  feathers 
directed  forwards.  In  the  Petrels  the  nostrils 
are  produced  in  a  tubular  form,  parallel  to  one 
another  for  a  short  distance  along  the  upper 
part  of  the  mandible,  with  the  orifices  turned 
forwards  (a,  Jig.  142.) 

The  septum  narium  is,  in  general,  complete, 
and  is  partly  osseous,  partly  cartilaginous.  It 
is  perforated  in  the  Swan  just  opposite  the 
external  nostrils.  The  surface  of  the  septum 
is  very  irregular  in  this  bird,  and  the  pituitary 
membrane  which  covers  it  is  highly  vascular. 

The  outer  side  of  each  of  the  nasal  passages 
gives  attachment  to  three  turbinated  laminae. 
The  inferior  one  is  a  simple  fold  adhering  to 
the  septum  narium  as  well  as  to  the  side  of  the 
nose;  the  middle  one  is  cartilaginous  and  is 
the  largest.  It  is  of  an  infundibular  figure, 
and  adheres  by  its  base  to  the  septum  of  the 
nose,  and  externally  to  the  cartilaginous  ala  or 
side  of  the  nostril.  It  is  convoluted  with  two 
turns  and  a  half  in  the  Anserine  Birds,  but 
in  the  Grallatores  it  is  compressed  and  forms 
only  one  turn  and  a  half.  The  superior  tur- 
binated lamina  (m  m,  fig.  140)  generally 
presents  the  form  of  a  bell ;  it  is  also  cartila- 
ginous, and  adheres  to  the  ethmoidal  and 
lachrymal  bones.  It  is  hollow,  and  divided 
into  two  compartments,  which  are  prolonged 
in  a  tubular  form  ;  the  internal  one  extends  to 


*  See    Cuvier,    Logons   d'Anat.  Coinp.  torn,  ii., 
and  Macartney  in  Hccs'  Cyclopaedia,  Art.  Birds. 
t  See  Montague's  Ornithological  Dictionary. 


310 


AVES. 


the  orbit,  the  external  terminates  behind  the 
middle  tu/binated  lamina  in  a  cul-de-sac. 
These  olfactory  laminae  differ  in  regard  to  tex- 
ture. In  the  Cassowary  and  Albatross  they 
are  said  to  be  membranous.  Cuvier  states  that 
they  appeared  to  him  to  be  bony  in  the  Horn- 
bill  and  Toucan.  We  have  found  this  to  be  the 
case  in  the  recent  Toucan.  The  organ  of  smell  in 
this  singular  species  is  confined  to  the  base  of  its 
enormous  beak,  (d,e,fig.  150.)  The  canal,  which 
is  traversed  by  the  air  and  odorous  particles  in 
inspiration,  forms  a  sigmoid  curve  in  the  vertical 
direction.  The  external  orifice  is  on  precisely 
the  same  perpendicular  line  as  the  internal, 
or,  as  it  is  generally  termed,  the  posterior  nasal 
aperture.  The  external  nostril  (d,  Jig.  150) 
being  situated  on  the  posterior  surface  of  the 
upper  mandible,  where  it  is  raised  above  the 
level  of  the  cranium,  is  consequently  directed 
backwards,  secure  from  all  injury  to  which  it 
might  be  exposed  while  the  bill  was  used  in 
penetrating  dense  and  interwoven  foliage. 
The  olfactory  canal  is  at  its  commencement 
of  a  cylindrical  form,  and  about  two  lines  in 
diameter.  It  passes  forwards  for  about  half  an 
inch,  receiving  the  projection  of  the  first  spongy 
bone,  then  bends  downwards  and  backwards, 
and  is  dilated  to  admit  the  projections  of  the 
two  other  spongy  bones.  From  this  point  it 
descends  vertically  to  the  palate,  at  first  con- 
tracted and  afterwards  dilating  to  form  the  in- 
ternal or  posterior  orifice,  (e,Jig.  150.)  The 
first  or  outermost  spongy  bone  is  almost  hori- 
zontal, and  has  its  convexity  directed  outwards. 
The  second  is  nearly  vertically  placed,  with  its 
convexity  directed  backwards  :  it  terminates  in 
a  narrow  point  below.  The  superior  spongy 
bone  is  about  the  size  and  shape  of  a  pea. 
All  these  bones  are  processes  from  the  inner 
and  posterior  parietes  of  the  nasal  passage; 
they  are  cellular,  and  air  is  continued  into 
them  from  the  cranial  diploe  ;  but  the  parietes 
of  the  nasal  passage  are  entire  and  smooth, 
and  lined  by  a  delicate  pituitary  membrane,  so 
that  there  is  no  direct  communication  between 
the  cells,  the  turbinated  bones,  or  of  the  man- 
dible and  the  nasal  passages. 

In  most  birds  the  nasal  cavities  communicate 
with  the  pharynx  by  two  distinct  but  closely 
approximated  apertures.  In  the  Cormorant, 
however,  these  join  into  one  before  their  termi- 
nation posteriorly,  which  is  consequently  by  a 
single  aperture.  The  olfactory  nerves  are  dis- 
tributed exclusively  to  the  pituitary  membrane 
covering  the  septum  narium  and  the  superior 
spongy  bone.  The  pituitary  membrane  is  of 
the  most  delicate  structure,  and  is  most  vas- 
cular, where  it  covers  the  superior  turbinated 
lamina,  and  becomes  thicker  and  more  villous 
as  it  descends  upon  the  middle  one.  It  every- 
where displays  numerous  pores  of  muciparous 
glands,  which  bedew  it  with  a  lubricating 
secretion. 

According  to  Scarpa  the  acuteness  of  smell 
is  exactly  in  proportion  to  the  development  of 
the  superior  turbinated  lamina,  to  which  the 
size  of  the  olfactory  nerve  corresponds.  The 
following  is  the  order  in  which,  according  to 


his  experiments,  birds  enjoy  the  sense  of  smell, 
beginning  with  those  in  which  it  is  most  acute : 
Grallatores,  Natatores,  Raptores,  Sccmsores, 
Insessores,  Rasores. 

There  is  still,  however,  much  obscurity 
with  reference  to  the  extent  to  which  Birds 
make  use  of  their  olfactory  organs.  It  has 
been  generally  asserted  that  birds  of  prey  are 
gifted  with  a  highly  acute  sense  of  smell,  and 
that  they  can  discover  by  means  of  it  the 
carcass  of  a  dead  animal  at  great  distances ; 
but  those  who  have  witnessed  the  rapidity  with 
which  the  Vultures  descend  from  invisible 
heights  of  the  atmosphere  to  the  carcass  of  an 
animal,  too  recently  killed  to  attract  them  by 
putrefactive  exhalations,  have  generally  been 
led  to  consider  them  as  being  directed  to  their 
quarry  by  sight.  "  That  this  is  the  case,"  Dr. 
Koget  observes,  "  appears  to  be  now  suffi- 
ciently established  by  the  observations  and 
experiments  of  Mr.  Audubon,  which  show  that 
these  birds  in  reality  possess  the  sense  of  smell 
in  a  degree  very  inferior  to  carnivorous  quadru- 
peds, and  that  so  far  from  guiding  them  to 
their  prey  from  any  distance,  it  affords  them  no 
indication  of  its  presence  even  when  close  at  hand . 
The  following  experiments  appear  to  be  perfect- 
ly conclusive  on  this  subject.  Having  pro- 
cured the  skin  of  a  deer,  Mr,  Audubon  stuffed 
it  full  of  hay ;  after  the  whole  had  become 
perfectly  dry  and  hard,  he  placed  it  in  the  mid- 
dle of  an  open  field,  laying  it  down  on  its  back 
in  the  attitude  of  a  dead  animal.  In  the 
course  of  a  few  minutes  afterwards  he  observed 
a  vulture  flying  towards  and  alighting  near  it. 
Quite  unsuspicious  of  the  deception,  the  bird 
immediately  proceeded  to  attack  it  as  usual  in 
the  most  vulnerable  points.  Failing  in  this 
object,  he  next  with  much  exertion  tore  open 
the  seams  of  the  skin  where  it  had  been  stitched 
together,  and  appeared  earnestly  intent  on  get- 
ting at  the  flesh,  which  he  expected  to  find 
within,  and  of  the  absence  of  which  not  one 
of  his  senses  was  able  to  inform  him.  Find- 
ing that  his  efforts,  which  were  long  reiterated, 
led  to  no  other  result  than  the  pulling  out  large 
quantities  of  hay,  he  at  length,  though  with 
evident  reluctance,  gave  up  the  attempt,  and 
took  flight  in  pursuit  of  other  game  to  which 
he  was  led  by  the  sight  alone,  and  which  he 
was  not  long  in  discovering  and  securing. 

"  Another  experiment,  the  converse  of  the 
first,  was  next  tried.  A  large  dead  hog  was 
concealed  in  a  narrow  and  winding  ravine, 
about  twenty  feet  deeper  than  the  surface  of 
the  earth  around  it,  and  filled  with  briers  and 
high  cane.  This  was  done  in  the  month  of 
July,  in  a  tropical  climate,  where  putrefaction 
takes  place  with  great  rapidity ;  yet,  although 
many  vultures  were  seen  from  time  to  time 
sailing  in  all  directions  over  the  spot  where  the 
putrid  carcass  was  lying,  covered  only  with 
twigs  of  cane,  none  ever  discovered  it;  but  in 
the  meanwhile  several  dogs  had  found  their 
way  to  it  and  had  devoured  large  quantities  of 
the  flesh."* 

*  See  Roget,  Bridgcwater  Treatise,  vol.  ii.  p.  406. 


AVES. 


311 


Organ  of  Tasle. — The  gustatory  sense  is  very 
imperfectly  enjoyed  in  birds,  which,  having  no 
manducatory  organs,  swallow  the  food  almost 
as  soon  as  seized.  The  tongue  is  organized 
chiefly  to  serve  as  a  prehensile  instrument,  and 
its  principal  modifications  will  be  treated  of 
under  the  head  of  the  Digestive  Organs.  It  is 
generally  sheathed  at  the  anterior  part  with 
horn  (hjjig.  152),  and  is  destitute  of  papillae 
except  at  its  base  (o,  fig.  152)  near  the  aper- 
ture of  the  larynx ;  these  papillae  are  not,  how- 
ever, supplied  by  a  true  gustatory  nerve,  but  by 
filaments  of  the  glossopharyngeal.  No  branch 
of  the  fifth  pair  goes  to  the  tongue. 

The  tongue  is  proportionally  largest  and 
most  fleshy  in  the  Parrot  tribe,  and  the  food 
is  detained  in  the  mouth  longer  in  these  than 
in  other  birds.  It  is  triturated  and  commi- 
nuted by  the  mandibles  certainly,  and  turned 
about  by  the  tongue,  which  here  seems  to  ex- 
ercise a  gustatory  faculty,  since  indigestible 
parts,  as  the  coat  of  kernels,  &c.  are  rejected. 
In  the  Lories  the  extremity  of  the  tongue  is 
provided  with  numerous  long  and  delicate  pa- 
pillae or  filaments  projecting  forwards. 

Organs  of  Touch. — With  respect  to  the  tactile 
instruments,  but  few  observations  can  be  made 
in  the  class  of  Birds.  The  anterior  extremities 
have  their  digital  extremities  undivided  and 
entirely  unfitted  for  the  exercise  of  this  sense, 
and  the  posterior  extremities  are  but  little  better 
organized  for  the  purpose.  The  integument 
covering  the  toes  is  very  sparingly  supplied 
with  nerves,  and  is  of  a  texture  scarcely  fitted 
for  ascertaining  the  superficial  qualities  of 
bodies.  However,  the  villi  on  the  under  sur- 
face of  the  toes  are  observed  to  be  remarkably 
long  in  the  Capercailzie  (Tetrao  urogallus), 
but  this  is  probably  for  the  purpose  of  enabling 
them  to  grasp  with  more  security  the  frosted 
branches  of  the  Norwegian  pine-trees.  The 
Parrots  seem  to  use  their  feet  more  like  instru- 
ments of  touch,  but  in  them  the  action  may 
be  merely  prehensile. 

The  only  organ  of  touch  respecting  which 
there  can  be  no  doubt  is  the  bill.  Even  where 
this  is  covered  with  a  hard  sheath  of  horn,  some 
filaments  of  the  fifth  pair  (c,fig.  150)  may  be 
traced  terminating  in  small  papillae ;  but  in  the 
Lamelli-rostral  water-birds  the  bill  is  covered 
by  a  softer  substance,  and  is  plentifully  supplied 
by  branches  of  the  fifth  pair  of  nerves.  (See 
Nerves.)  In  the  Woodcocks  and  Snipes  the 
long  bill  is  so  organized  that  it  is  used  as  a 
probe  in  marshes  and  soft  ground  to  feel  for 
the  small  worms  and  slugs  that  constitute  their 
food. 

The  cire  in  the  Falconida,  the  wattles  of 
the  Wattle-birds  (Philedon  carunculatus  and 
Gkmcopis  cinerea)  and  of  the  Cock,  the  ca- 
runcles of  the  King-Vulture  and  Turkey,  may 
also  be  regarded  in  some  degree  as  organs  of 
touch. 

Organs  of  Digestion. — The  digestive  function 
in  birds  is  necessarily  extremely  powerful  and 
rapid  in  order  to  supply  the  waste  occasioned 
by  their  extensive,  frequent,  and  energetic  mo- 
tions, and  in  accordance  with  the  rapidity  of 


their  circulation  and  their  high  state  of  irrita- 
bility. * 

The  parts  to  be  considered  with  reference  to 
this  function  are  the  rostrum  or  beak,  the 
tongue,  the  oesophagus,  the  stomach  which  is 
always  divided  into  a  glandular  and  muscular 
portion,  the  intestines,  and  the  cloaca. 

The  glandular  organs  of  the  digestive  system 
are  the  salivary  glands,  the  proventricular  fol- 
licles, the  liver,  pancreas,  and  spleen. 

The  beak  consists  of  the  maxillary  and  inter- 
maxillary bones,  which  in  place  of  teeth  are 
provided  with  a  sheath  of  horny  fibrous  mate- 
rial, exactly  similar  to  that  of  which  the  claws 
are  composed:  this  sheath  is  moulded  to  the 
shape  of  the  osseous  mandibles,  being  formed  by 
a  soft  vascular  substance  covering  these  parts,  and 
its  margins  are  frequently  provided  with  horny 
processes  or  laminae  secreted  by  distinct  pulps, 
and  analogous  in  this  respect  to  the  whalebone 
lamina;  of  the  Whale:  M.  Geoffrey  St.  Hilaire 
has  described  a  structure  in  the  bill  of  birds 
which  presents  a  closer  approach  to  a  dentary 
system.  In  a  foetus  of  a  Perroquet  nearly  ready 
for  hatching,  he  found  that  the  margins  of  the 
bill  were  beset  with  tubercles  arranged  in  a  re- 
gular order  and  having  all  the  exterior  appear- 
ances of  teeth :  these  tubercles  were  not,  indeed, 
implanted  in  the  jaw-bones,  but  formed  part 
and  parcel  of  the  exterior  sheath  of  the  bill. 
Under  each  tubercle,  however,  there  was  a  ge- 
latinous pulp,  analogous  to  the  pulps  which 
secrete  teeth,  but  resting  on  the  edge  of  the 
maxillary  bones,  and  every  pulp  was  supplied 
by  vessels  and  nerves  traversing  a  canal  in  the 
substance  of  the  bone.  These  tubercles  form 
the  first  margins  of  the  mandibles,  and  their 
remains  are  indicated  by  canals  in  the  horny 
sheath  subsequently  formed,  which  contain  a 
softer  material,  and  which  commence  from 
small  foramina  in  the  margin  of  the  bone. 

The  different  degrees  of  hardness  and  varieties 
of  form  of  the  beak  exercise,  Cuvier  observes,f 
as  much  influence  upon  the  nature  of  birds  as 
the  number  and  figure  of  the  teeth  do  upon 
that  of  Mammals. 

The  beak  is  hardest  in  those  birds  which 
tear  their  prey,  as  in  Eagles  and  Falcons ;  or 
in  those  which  bruise  hard  seeds  and  fruits,  as 
Parrots  and  Gros-beaks;  or  in  those  which  pierce 
the  bark  of  trees,  as  Woodpeckers,  in  the  larger 
species  of  which  the  beak  absolutely  acquires 
the  density  of  ivory. 

The  hardness  of  the  covering  of  the  beak 
gradually  diminishes  in  those  birds  which  take 
less  solid  nourishment,  or  which  swallow  their 
food  entire;  and  it  changes  at  last  to  a  soft  skin 
in  those  which  feed  on  tender  substances,  or 
which  have  occasion  to  probe  for  their  food  in 
muddy  or  sandy  soils,  or  at  the  bottom  of  the 
water,  as  Ducks,  Snipes,  Woodcocks,  &,c. 

C&teris paribus,  a  short  beak  must  be  stronger 
than  a  long  one,  a  thick  one  than  a  thin  one,  a 
solid  one  than  one  which  is  flexible ;  but  the 

*  The  Cormorant  readily  devours  six  or  eight 
pounds  of  fish  daily. 

t  Anatomie  Compuree,  torn.  ii.  p.  192. 


312 


AVES. 


general   form  produces  infinite  variety  in  the 
application  of  the  force. 

A  compressed  beak  with  sharp  edges  and  a 
hooked  extremity  characterizes  both  the  Birds 
of  Prey  properly  so  called,  which  destroy  the 
smaller  quadrupeds  and  birds  (fig.  112)  ;  and 
also  the  carnivorous  species  of  a  different  order 
that  live  on  fish,  as  the  Petrels  (Jig.  142),  Al- 
Fig.  142. 


of  being  as  deep  as  it  is  long),  and  the  Skimmer 
(Rhyncops),  in  which  the  still  more  singular 
structure  obtains  of  an  inequality  in  the  length 
of  the  two  mandibles,  the  upper  one  being  con- 
siderably the  shortest;  so  that  this  bird  can 
only  get  its  food,  which  consists  of  floating 
marine  animals,  by  pushing  them  before  it 
as  it  skims  along  the  surface  of  the  water. 


Fig.  144. 


Bill  of  the  Petrel. 

batrosses,  Frigate-bird,  and  Tropic-bird.  But 
in  the  Raptures  it  is  comparatively  shorter  and 
stronger,  and  in  some  genera  a  tooth-like  pro- 
cess on  either  side  adds  considerably  to  its 
destructive  powers :  hence  the  Falcons  which 
possess  this  armature  are  reckoned  the  more 
'  noble '  and  courageous  Birds  of  Prey. 

The  Insessorial  Shrikes  which  have  their  bill 
similarly  armed  do  not  yield  in  courage  to  the 
Hawks,  notwithstanding  their  small  size,  and 
the  comparative  feebleness  of  their  wings  and 
feet:  (Jig.  11 5.) 

As  the  bill  becomes  narrower  and  straighter, 
it  characterizes  birds  of  a  voracious  habit,  but 
less  daring  in  their  attacks  on  other  birds, 
such  as  the  Crows,  Magpies,  &c.,  (jig.  116) ; 
and  the  compressed  knife-shaped  bill  is  asso- 
ciated with  similar  habits  in  the  Water-birds, 
as  the  Gulls,  Grebes,  Dabchicks,  &c. 

Another  kind  of  strong 
and  trenchant  bill,  which 
is  more  elongated  and 
without  a  hook,  serves  to 
cut  and  break,  but  not 
to  tear :  this  form  of  bill 
characterizes  the  Waders 
which  frequent  the  water 
and  prey  upon  animals 
that  make  resistance  in 
that  element,  as  reptiles, 
fishes,  &c.  In  the  He- 
rons and  Bitterns  the 
bill  is  straight;  in  the  Ibis  it  is  curved  down- 
wards (fig.  123);  in  the  Jabiru  (fig.  143)  it 
is  curved  in  the  contrary  direction. 


Fig.  143. 


Bill  of  the  Skimmer. 

Lastly,  there  are  trenchant  bills  which 
are  depressed  or  flattened  horizontally ;  they 
serve  to  seize  fishes  and  reptiles,  and  other 
large  objects;  the  Boat-bill  (Cancroma) 
exhibits  a  bill  of  this  kind  k(fig.  145),  which 
is  also  ser-  Fig,  145. 

rated   at    the 

edges.    Some          /^^- —        ^  ,  r~\\ 
speciesofFly-       /^ 
catcher     and 
Tody       have 
this   form    of 
beak     on     a 
small  scale .  Biu  °f  the  Boat-bill. 

Of  the  blunt-edged  bills  we  may  first  notice 
those  which  are  flattened  horizontally.  When 
a  bill  of  this  description  is  long  and  strong,  as 
in  the  Pelecan  (jig-  146),  it  selves  to  seize  a 
large  but  feebly  resisting  prey,  as  fishes. 


Fig.  146. 


Bill  of  the  Pelecan. 

When  it  is  long  and  weak,  as  in  the  Spoon- 
bill, which  derives  its  name  from  the  dilated 
extremity  of  the  mandibles,  it  is  only  available 
to  seize  amid  sand,  mud,  or  water,  very  small 
Crustaceans,  Mollusks,  &c.  (Jig.  147.) 

Fig.  147. 


Bill  of  the  Jabiru. 


Some  trenchant  or  sharp-edged  bills  are 
so  compressed  as  to  resemble  the  blade  of 
a  knife,  and  can  only  serve  to  seize  small  ob- 
jects, which  are  immediately  swallowed  :  such 
is  the  form  of  the  beak  in  the  Auks,  Puffins, 
Coulterneb,  (where  it  has  the  further  peculiarity 


Bill  of  the  Spoonbill. 

The  more  or  less  flattened  bills  of  Ducks,  the 
more  conical  ones  of  Geese  and  Swans,  and 
that  of  the  Flamingo,*  of  which  the  extremities 

*  It  is  singular  that  it  should  ever  have  been 
supposed  that  the  upper  mandible  was  alone  move- 
able,  and  the  lower  mandible  perfectly  immoveable, 
in  the  Flamingo,  since  precisely  the  contrary  is  the 


AVES. 


313 


of  the  mandibles  are  bent  downwards  abruptly 
(Jig.   148),   have  all  transverse  horny  lamina; 


Fig.  148. 


which  are  nearly  allied  to  the  Anat'ulee,  the  la- 
teral laminae  are  developed  into  small  conical 
tooth-like  processes,  which  serve  to  hold  fast 
the  fishes,  which  the  Goosander  destroys  in 
great  numbers. 

Fig.  149. 


Bill  of  the  Flamingo. 


arranged  along  their  edges,  which,  when  the 
bird  lias  seized  any  object  in  the  water,  serve, 
like  the  whalebone  laminae  of  the  Whale,  to  give 
passage  to  the  superfluous  fluid.  The  aquatic 
habits  of  all  these  birds  are  in  harmony  with 
this  structure.  In  the  Goosanders  (Mergus), 


Bill  of  the  Goosander. 

The  bills  of  the  Toucans  and  Hornbills  are 
remarkable  for  their  enormous  size,  which  is 
sometimes  equal  to  that  of  the  whole  bird. 
The  substance  of  the  beak  in  these  cases  is 
extremely  light  and  delicately  cellular,  without 
which  the  equilibrium  necessary  for  flight 
would  have  been  destroyed.  The  singularity 
of  the  structure  of  these  bills  demands  a  more 
particular  consideration. 

The  osseous  portions  of  the  mandibles  of 
the  Toucan  (fig.  150)  are  adapted  to  cora- 


Fig.  150. 


Bitt  of  the  Toucan. 


bine,  with  great  bulk,  a  due  degree  of 
strength  and  remarkable  lightness,  and  their 
structure  is  consequently  of  a  most  beautiful 
and  delicate  kind.  The  external  parietes  are 
extremely  thin,  especially  in  the  upper  beak  : 
they  are  elastic,  and  yield  in  a  slight  degree  to 
moderate  pressure,  but  present  considerable 
resistance  if  the  force  be  increased  for  the  pur- 
pose of  crushing  the  beak.  At  the  points  of 
the  mandibles  the  outer  walls  are  nearly  a  line 
in  thickness ;  at  other  parts  in  the  upper  beak 


case.  In  the  specimen  which  we  dissected  (see 
Proceedings  of  the  Zoological  Society,  Part  ii. 
p.  141)  the  upper  mandible  was  so  firmly  fixed  to 
the  cranium  as  only  to  be  moved  with  that  part, 
while  the  lower  mandible  was  freely  moveable 
when  the  head  was  fixed.  The  Flamingo  is  remark- 
able for  applying  the  upper  mandible  to  the  soil, 
which  it  shovels  backwards  in  searching  for  its 
food. 


they  are  much  thinner,  varying  from  one- 
thirtieth  to  one-fiftieth  part  of  an  inch,  and  in 
the  lower  beak  are  from  one-twentieth  to  one- 
thirtieth  of  an  inch  in  thickness. 

On  making  a  longitudinal  section  of  the  upper 
mandible  (a,jig.  150)  in  the  Rhamphastos  Touco, 
its  base  is  seen  to  include  a  conical  cavity  about 
two  inches  in  length  and  one  inch  in  diameter, 
with  the  apex  directed  forwards.  The  walls  of 
this  cone  consist  of  a  most  beautiful  osseous 
net-work,  intercepting  irregular  angular  spaces, 
varying  in  diameter  from  half  a  line  to  two 
lines.  From  the  parietes  of  the  cone  a  net- 
work of  bony  fibres  is  continued  to  the  outer 
parietes  of  the  mandible,  the  fibres  which  imme- 
diately support  the  latter  being  almost  invariably 
at  right  angles  to  the  part  in  which  they  are  in- 
serted. The  whole  of  the  mandible  anterior  to 
the  cone  is  occupied  with  a  similar  net-work,  the 
meshes  of  which  are  largest  in  the  centre  of 


314 


AVES. 


the  beak,  in  consequence  of  the  union  which 
takes  place  between  different  small  fibres  as 
they  pass  from  the  circumference  inwards.  It 
is  worthy  of  observation  that  the  principle  of 
the  cylinder  is  introduced  into  this  elaborate 
structure  :  the  smallest  of  the  supporting  pillars 
of  the  mandibles  are  seen  to  be  hollow  or 
tubular  when  examined  with  the  microscope. 
The  structure  is  the  same  in  the  lower  man- 
dible (ntjjig.  150),  but  the  fibres  composing 
the  net-work  are  in  general  stronger  than  those 
of  the  upper  mandible. 

The  medullary  membrane  lining  these  cavi- 
ties appears  to  have  but  a  small  degree  of 
vascularity.  Processes  of  the  membrane,  ac- 
companying vessels  and  nerves,  decussate  the 
conical  cavity  at  the  base  of  the  beak.  The  air  is 
admitted  to  the  interior  of  the  upper  mandible 
from  a  cavity  (b,fg.  150)  situated  anterior  to 
the  orbit,  which  communicates  at  its  posterior 
part  with  the  air-cell  continued  into  the  orbit, 
and  at  its  anterior  part  with  the  maxillary 
cavity.  The  nasal  cavity  is  closed  at  every 
part  except  at  its  external  and  internal  aper- 
tures by  the  pituitary  membrane,  and  has 
no  communication  with  the  interior  of  the 
mandible.  * 

The  horny  sheath  of  the  mandibles  in  the 
Hornbills  and  Toucans  is  so  thin  that  it  often 
becomes  irregularly  notched  at  the  edge  from 
use.  The  Hornbills  have,  besides,  upon  their 
enormous  beak,  horn-like  prominences  of  the 
same  structure  and  of  different  forms,  the  use 
of  which  is  not  known. 

The  Trogons,  Touracos,  Buccos,  &c.  exhibit 
forms  of  the  bill  which  are  intermediate  to  that 
of  the  large  but  feeble  bill  of  the  Toucans,  and 
the  short,  but  hard,  strong,  and  broad  bill  of 
the  Parrot-tribe,  which  is  also  hooked,  so  as 
to  assist  in  climbing,  like  a  third  foot:  (Jig* 
128.) 

The  short,  conical,  and  vaulted  beak  of  the 
Rasores  (fig.  121)  serves  to  pick  up  with  due 
rapidity  the  vegetable  seeds  and  grains  which 
constitute  their  food,  as  well  as  small  insects, 
as  ants,  &c.  with  which  the  young  are  frequently 
nourished. 

The  bills  of  the  small  Insessorial  or  Pas- 
serine birds  present  every  gradation  of  the 
conical  form,  from  the  broad-based  cone  of  the 
Hawfinch  to  the  almost  filamentous  cone  of  the 
Humming-birds  (jig.  117,  125),  and  each  of 
these  forms  influences  the  habits  of  the  species 
in  the  same  manner  as  in  the  larger  birds.  The 
short  and  strong-billed  Insessores  live  on  seeds 
and  grains ;  those  with  a  long  and  slender  bill 
on  insects  or  vegetable  juices.  If  the  slender 
bill  be  short,  flat,  and  the  gape  very  wide,  as 
in  Swallows,  the  bird  takes  the  insects  while 
on  the  wing  (Jiff.  118) ;  if  the  bill  be  elongated 
and  endowed  with  sufficient  strength,  as  in  the 
Hoopoes,  it  serves  to  penetrate  the  soil  and 
pick  out  worms,  &c. 

Of  all  bills,  the  most  extraordinary  is  that  of 
the  Cross-bill,  in  which  the  extremities  of  the 
mandibles  curve  towards  opposite  sides  and 

*  See  Anatomical  Appendix  to  Gould's  Mono- 
graph on  the  Ramphastidfc ,  fol. 


cross  each  other  at  a  considerable  angle — a  dis- 
position which  at  first  sight  seems  directly 
opposed  to  the  natural  intention  of  a  bill. 
With  this  singular  disposition,  the  Cross-bill, 
however,  possesses  the  power  of  bringing  the 
points  of  the  mandibles  into  contact  with  each 
other ;  and  Mr.  Yarrell,  in  his  excellent  paper 
on  the  Anatomy  of  the  Beak  of  this  b;rd,  ob- 
serves that,  notwithstanding  M.  Button's  asser- 
tion to  the  contrary,  it  can  pick  up  the  smallest 
seeds,  and  shell  or  husk  hemp  and  similar 
seeds  like  other  birds.  He  further  shows  that 
the  disposition  and  power  of  the  muscles  is  such 
that  the  bill  gains  by  its  very  apparent  defect 
the  requisite  power  for  breaking  up  the  pine- 
cones  that  constitute  its  natural  food.  In  a 
pair  of  Cross-bills  which  were  kept  for  some 
time  in  captivity,  one  of  their  principal  occu- 
pations, Mr.  Yarrell  observes,  "  was  twisting 
out  the  ends  of  the  wires  of  their  prison,  which 
they  accomplished  with  equal  ease  and  dexterity. 
A  short  flat-headed  nail  that  confined  some 
strong  net-work  was  a  favourite  object  upon 
which  they  tried  their  strength,  and  the  male, 
who  was  usually  pioneer  in  every  new  exploit, 
succeeded,  by  long-continued  efforts,  in  draw- 
ing this  nail  out  of  the  wood,  though  not 
without  breaking  off  the  point  of  his  beak  in 
the  experiment.  Their  unceasing  destruction 
of  cages  at  length  brought  upon  them  sentence 
of  banishment."  He  concludes  his  memoir  by 
observing  that  "  the  remarks  of  Buffon  on  the 
beak  of  this  bird,  which  he  characterizes  as 
'  an  error  and  defect  of  nature,  and  a  useless 
deformity,'  exhibit,  to  say  the  least  of  them, 
an  erroneous  and  hasty  conclusion,  unworthy 
of  the  spirit  of  the  science  he  cultivated. 
During  a  series  of  observations  on  the  habits 
and  structure  of  British  Birds,  t  have  never 
met  with  a  more  interesting  or  beautiful  ex- 
ample of  the  adaptation  of  means  to  an  end 
than  is  to  be  found  in  the  tongue,  the  beak, 
and  its  muscles,  in  the  Cross-bill."  * 

The  tongue,  as  has  been  already  observed, 
can  hardly  be  considered  as  an  organ  of  taste 
in  Birds,  since,  like  the  mandibles,  it  is  gene- 
rally sheathed  with  horn.  It  is  principally 
adapted  to  fulfil  the  offices  of  a  prehensile 
organ  in  association  with  the  beak,  and  it  pre- 
sents almost  as  many  varieties  of  form.  Orni- 
thologists have  not  yet  perhaps  derived  all  the 
advantages  which  a  study  of  the  modifications 
of  the  tongue  might  afford  in  determining  the 
natural  affinities  of  birds. 

The  os  hyoides  very  much  resembles  that  of 
Reptiles.  Its  parts  have  been  minutely  studied 
by  Geoffroy  St.  Hilaire,  who  has  bestowed 
upon  them  separate  names:  (a,  Jig.  151)  is  the 
glosso-hyal,  b  the  basi-hyal,  d  d  the  apo-hyals, 
e  e  the  cerato-hyals,  c  the  uro-hyal.  The 
body,  or  basi-hyal  element,  is  more  thickened 
than  the  rest :  in  some  birds  it  is  cylindrical. 
The  length  of  the  tongue  depends  chiefly  on  that 
of  the  lingual  process  or  glosso-hyal  element. 
In  most  birds  it  is  lengthened  out  by  a  carti- 
lage a'  appended  to  its  extremity.  This  is  re- 
markable in  the  Swan  and  other  Latnelli-rostres. 

*  Zool.  Journal,  vol.  iv.  p.  464. 


Iii  the  Humming-bird,  and  especially  in 
the  Toucan  and  Woodpecker,  the  horny  sheath 
of  the  glosso-hyal  presents  singular  pecu- 
liarities. In  the  Humming-bird  it  is  divided 
at  its  extremity  into  a  pencil  of  fine  hairs, 
well  fitted  for  imbibing  the  nectar  and  farina 
of  flowers.  In  the  Toucan's  tongue  (fig.  152) 
the  sheath  gives  off  from  the  lateral  margins 
stiff  bristle-like  processes  which  project  for- 
wards ;  this  structure  is  continued  to  the  apex, 


99 

Os  hyoides  and  larynx 
Swan. 


Fig.  152. 


and  the  tongue  so  provided  becomes  an  in- 
strument for  testing  the  softness  and  ripe- 
ness of  fruit,  and  the  fitness  of  other  objects 
for  food,  thereby  acting  as  a  kind  of  antenna 
or  feeler.  A  similar  but  less  developed  struc- 
ture is  found  in  the  tongue  of  the  frugivorous 
Touraco. 

In  the  Woodpeckers  the  apex  of  the 
horny  sheath  (a,  fig.  153,  154)  gives  off  at,  the 
sides  short-pointed  processes  directed  back- 
wards, which  thus  convert  it  into  a  barbed 
instrument,  fitted  for  holding  fast  the  insects 
which  its  sharp  point  has  transfixed,  after  the 
strong  beak  has  dislodged  them  from  their 
hiding  places.  The  cornua  of  the  os  hyoides 
in  the  \Voodpecker  extend  backwards  to  the 
vertebral  column,  wind  round  the  back  of  the 
head,  and  converge  as  they  pass  forwards  to  be 
inserted  in  a  canal  generally  on  the  right  side  of 
the  upper  mandible  (d,  e,  jig.  153,  154.) 

Fig.  153. 


Cranium  and  tongue  of  a  Woodpecker. 

One  of  the  most  remarkable  structures  which 
the  tongue  presents  in  this  class  is  met  with  in 
the  Flamingo,  where  it  is  remarkable  both  for  its 
size,  texture,  and  singular  armature.  The  tongue 
is  almost  cylindrical,  slightly  flattened  above, 
and  obliquely  truncate  anteriorly,  so  as  to  cor- 
respond with  the  form  of  the  inferior  mandible. 
The  pointed  extremity  of  the  truncated  part  is 
supported  beneath  by  a  small  horny  plate. 
Along  the  middle  of  the  upper  surface  there  is 
a  moderately  deep  and  wide  longitudinal 
furrow ;  on  either  side  of  which  there  are 

(fr"m  twenty  to  twenty-five  recurved  spines, 
m  one  to  three  lines  in  length.  These 
nes  are  arranged  in  an  irregular  alternate 
ies  :  the  outer  ones  being  the  smallest,  which 


Tongue  of  tJie  Toucan. 
may  almost  be  considered  as  a  distinct  row. 
At  the  posterior  part  of  the  tongue  there  are 
two  groups  of  smaller  recumbent  spines  di- 
rected towards  the  glottis.  The  substance  of 
the  tongue  is  not  muscular,  but  is  chiefly 
composed  of  an  abundant  elastic  cellular  sub- 
stance, permeated  by  an  oily  fat. 

In  the  Raptures  the  tongue  is  of  a  mode- 
rate length, — broad,  and  somewhat  thick,  and 
has  a  slight  division  at  the  tip.  In  the  Vultures 
its  sides  can  be  voluntarily  approximated  so 
as  to  form  a  canal,  and  its  margins  are  pro- 
vided with  retroverted  spines.  In  the  Raven 
it  is  bifid  at  the  apex. 

In  the  Struthious  birds,  in  many  of  the 
Waders,  and  in  the  Pelecanida:,  the  tongue  is 
remarkably  short. 

In  the  Parrots  it  is  thick  and  fleshy,  serves 
admirably  to  keep  steady  the  nut  or  seed  upon 
which  the  strength  of  the  mandibles  is  exerted, 
and  is  applied  to  the  kernel  so  extracted,  as  if 
to  ascertain  its  sapid  qualities. 

The  following  are  the  muscles  of  the  tongue 
in  birds. 

1st.  The  Genio-hyoideus  of  Vicq  d'Azyr, 
or  the  Mylo-hyoideus  according  to  Cuvier. 
This  is  a  thin  layer  of  fibres  attached  to  the 
lower  and  inner  border  of  the  lower  jaw,  and 
running  transversely  to  a  mesial  tendon  which 
separates  them,  and  extends  to  the  uro-hyal. 
It  raises  the  tongue  towards  the  palate. 

2d.  The  Stylo-hyoideus  arises  from  the  upper 
and  back  part  of  the  lower  jaw,  and  divides  into 
three  or  more  portions :  the  posterior  descends 
obliquely  forwards,  and  is  inserted  into  the 
tendinous  commissure  of  the  preceding  mus- 
cle; the  middle  portion  is  inserted  into  the 
'  uro-hyal :'  the  anterior  fasciculus  is  inserted 
into  the  side  of  the  basi-hyal  above  the  trans- 
verse hyo-glossus.  The  actions  of  these  dif- 
ferent portions  vary  according  to  their  insertion; 
the  first  and  second  depress  the  apex  of  the 
tongue  by  raising  its  posterior  appendage, 
(uro-hyal,)  the  third  raises  the  tongue  and 
os  hyoides,  and  draws  it  to  one  side  when  it 
acts  singly. 

3d.  The  Genio-hyoideus  arises  by  two  fleshy 


316 


AVES. 


bands  from  the  lower  and  internal  edge  of  the 
lower  jaw;  these  unite  and  surround  the  cerato- 
hyals  or  cornua  of  the  os  hyoides ;  and  as  they 
draw  forward  the  os  hyoides,  protrude  the 
tongue  from  the  beak. 

4th.  The  Cerato-hyoideus  passes  from  the 
rerato-hyal  to  the  uro-hyal,  and  is  therefore 
subservient  to  the  lateral  movements  of  the 
tongue. 

5th.  The  Sterno-hyoidei  are  replaced  by  a 
slip  of  muscle  which  extends  from  the  anterior 
surface  of  the  upper  larynx  to  be  attached  to 
the  base  of  the  glosso-hyal. 

6th.  A  small  and  short  muscle  is  single  or 
azygos  ;  it  passes  from  the  basi-hyal  to  the 
under  part  of  the  glosso-hyal ;  it  depresses  the 
tip  of  the  tongue  and  elevates  its  base. 

7th.  A  short  muscle  which  arises  from  the 
junction  of  the  basi-hyal  with  the  cerato-  and 
uro-hyals,  and  is  inserted  into  the  upper  and 
outer  angle  of  the  base  of  the  glosso-hyal. 

All  these  muscles  are  remarkably  large  in 
the  Woodpecker,  in  which  there  is  a  singular 
pair  of  muscles  that  may  be  termed  Cerato- 
tracheales,  (h,  jig.  154.)  They  arise  from  the 
trachea  about  eight  lines  from  the  upper  larynx, 
twist  four.times  spirally  round  the  trachea,  and 
then  pass  forward  to  be  inserted  into  the  base 
of  the  cerato-hyals.  This  is  the  principal  re- 
tractor of  the  singular  tongue  in  this  species. 

Salivary  glands. — The  salivary  organs,  being 
in  general  developed  in  a  degree  corresponding 
to  the  extent  of  the  changes  which  the  food 
undergoes  in  the  mouth,  and  the  length  of 
time  during  which  it  is  there  detained,  are  by 
no  means  so  conspicuous  a  part  of  the  diges- 
tive system  in  Birds  as  in  Mammals.  Glands 
which  pour  out  their  secretion  upon  the  food 
prior  to  deglutition  are,  however,  met  with  in 
every  bird,  but  vary  in  number,  position,  and 
complexity  of  structure. 

In  some  species,  as  the  Crow,  they  are  of 
the  simplest  structure,  consisting  of  a  series 
of  unbranched,  cone-shaped  follicles  or  tubules, 
opening  separately  upon  the  mucous  mem- 
brane of  the  mouth,  along  the  sides  of  which 
cavity  they  are  situated.  They  pour  out  a 
viscid  mucus,  and  are  the  only  traces  of  a 
salivary  system  met  with  in  this  bird. 

In  many  other  birds,  and  especially  in  the 
Scratching,  Wading,  and  Swimming  Orders, 
glands  of  the  conglomerate  structure  are  found 
beneath  the  lower  jaw,  analogous  to  the  sub- 
maxillary  glands  of  quadrupeds. 

In  the  Goose  they  occupy  the  whole  of  the 
anterior  part  of  the  space  included  by  the  rami 
of  the  lower  jaw,  being  of  an  elongated  form, 
flattened  and  closely  united  together  at  the 
middle  line.  On  either  side  of  this  line  the  mu- 
cous membrane  of  the  mouth  presents  inter- 
nally a  series  of  pores,  each  of  which  is  the 
terminal  orifice  of  a  distinct  gland  or  aggre- 
gate of  ramified  ducts. 

A  third  and  higher  form  of  salivary  gland, 
in  which  the  secretion  of  the  conglomerate 
mass  is  conveyed  into  the  mouth  by  a  single 
duct,  is  found  in  the  Woodpeckers  and  some 
species  of  the  Rapacious  Order.  In  the  latter 
birds  these  glands  are  termed,  from  their  situ- 


Fig.  154. 


Tongue  and  salivary  glands,  Woodpecker. 
ation,  anterior  palatine:    in    the   Pica    thej 
correspond   to  the  parotid  and  sublingual 
Quadrupeds. 

The  sublingual  glands  of  the  Woodpecker 
are  of  extraordinary  size,  extending  from  the 
angle  to  the  symphysis  of  the  lower  jaw.  The1 
single  ducts  of  each  gland  unite  just  before 
their  termination,  which  is  a  simple  orifice 
the  apex  of  the  mouth.  The  structure  of  tl 
glands  is  shown  at  i,  k,  Jig.  154. 

Besides  the  preceding,  which  may  be  con- 
sidered as  the  true  salivary  glands,  there  are 
numerous  accessory  follicles  in  different  parts 
of  the  oral  apparatus  of  birds.  In  the  Water- 
hen  ( Galimula  chloropus)  there  is  a  series  o 
ccecal  glandular  tubes  along  each  side  of  the 
tongue ;  and  it  is  interesting  to  note  that  glan- 


AVES. 


317 


clular  follicles  are  found  abundantly  developed 
on  the  tongues  of  the  Chelonian  and  Saurian 
reptiles.  Similar  elongated  follicles  are  situated 
along  the  margin  of  the  lower  jaw,  resembling 
in  their  parallel  pectinated  disposition  the  bran- 
chiae of  Fishes.  In  the  Goose  the  corresponding 
follicles  are  longer  and  wider,  and  are  situated 
near  the  sides  of  the  tongue.  In  the  Raven  these 
mucous  follicles  are  narrower  but  longer. 

The  food,  after  being  embued  with  the  secre- 
tion of  the  preceding  glands,  is  poised  upon 
the  tongue  and  swallowed  partly  by  means 
of  the  pressure  of  the  tongue  against  the  palate, 
partly  by  a  sudden  upward  jerk  of  the  head. 
The  posterior  apertures  of  the  nostrils  being 
generally  in  the  form  of  narrow  fissures  are 
undefended  by  a  soft  palate  or  uvula  ;  and  the 
laryngeal  aperture,  which  is  of  a  similar  form, 
is  in  like  manner  unprovided  with  an  epi- 
glottis, but  is  defended  by  the  retroverted 
papillae  at  the  base  of  the  tongue.  In  many 
birds,  indeed,  as  the  Albatross  and  Coot,  there 
is  a  small  cartilage  in  the  usual  place  of  an 
epiglottis,  but  insufficient  to  cover  more  than 
a  very  small  part  of  the  laryngeal  aperture. 
Nitzsch  lias  devoted  a  treatise  to  these  rudimen- 
tary epiglottides  in  Birds.* 

With  respect  to  the  fauces  the  remarkable 
instance  of  a  dilatation  of  these  parts  in  the 
Pelecan  must  not  be  forgotten.  The  exten- 
sibility of  the  membrane  between  the  rami  of 
the  lower  jaw  admits  of  its  formation  into  a 
bag  (a,  Jig.  146),  which  is  calculated  to  contain 
ten  quarts  of  water,  and  serves  as  a  receptacle  for 
fishes,  making  in  that  state  a  conspicuous  appen- 
dage to  the  huge  bill ;  when  empty  it  can  be 
contracted  so  as  to  be  hardly  visible.  By  means 
of  this  mechanism  a  quantity  of  food  can  be 
transported  to  the  young ;  and,  as  in  disgorging 
the  bleeding  fishes  the  parent  presses  the 
bottom  of  the  sac  against  her  breast,  this 
action  has  probably  given  rise  to  the  fable 
of  her  wounding  herself  to  nourish  the  young 
with  her  own  blood. 

A  remarkable  provision  of  an  analogous  na- 
ture is  met  with  in  the  Bustard  as  a  sexual  pecu- 


liarity^g.155).  In 
the  male  there  is  a 
membranous  sac 
extending  for  some 
way  down  the  an- 
terior part  of  the 
neck  capable  of 
holding  several 
quarts  of  water; 
it  communicates 
with  the  mouth  by 
an  aperture  be- 
neath the  tongue. 
It  is  not  found  ex- 
cept in  the  mature 
bird.  It  is  sup- 
posed to  serve  the 
purpose  of  provid- 
ing the  female  and 
young  during  the 
breeding  season 


Fig.  155. 


Faucial  bag  of  the  Bustard. 


*  See  Meckel's  Archiven,  1826,  p.  613. 


with  water,  and  hence  may  not  be  developed  to 
its  full  extent  except  at  that  period. 

The  Swift  presents  an  analogous  dilatation  of 
the  membrane  of  the  fauces  at  the  base  of  the 
lower  jaw  and  upper  part  of  the  throat:  it  is 
most  developed  at  the  period  of  rearing  the 
young,  when  it  is  generally  found  distended 
with  insects  in  the  old  birds  that  are  shot  while 
on  the  wing.  This  receptacle  is  of  a  rounded 
form,  and  communicates  with  the  fauces  by 
a  wider  opening  than  that  of  the  Bastard ;  it  is 
also  proportionally  of  less  extent.  A  similar 
structure  obtains  in  the  Rook  and  probably  in 
other  Insectivorous  birds. 

The  oesophagus  (tf,  fig.  171  :  «,  fig.  156, 
158),  like  the  neck,  is  usually  very  long  in  birds  : 
as  it  passes  down,  it  generally  inclines  towards 
the  right  side ;  it  is  partially  covered  by  the  tra- 
chea (G,fig.  171),  and  connected  to  the  sur- 
rounding parts  by  a  loose  cellular  tissue.  It  is 
wide  and  dilatable,  corresponding  to  the  im- 
perfection of  the  oral  instruments  as  comminu- 
tors  of  the  food.  In  the  rapacious  and  especially 
in  the  piscivorous  birds  it  is  of  great  capacity, 
enabling  the  latter  to  swallow  the  fishes  entire, 
and  serving  also  in  many  Waders  and  Swim- 
mers as  a  temporary  repository  of  food. 

When  the  Cormorant  has  by  accident  swal- 
lowed a  large  fish,  which  sticks  in  the  gullet, 
it  has  the  power  of  inflating  that  part  to  its 
utmost,  and  while  in  that  state  the  head  and 
neck  are  shaken  violently,  in  order  to  promote 
its  passage.  In  the  Gannet  the  oesophagus  is  ex- 
tremely capacious,  and,  as  the  skin  which  covers 
it  is  equally  dilatable,  five  or  six  herrings  may  be 
contained  therein.  In  both  these  species  it 
forms  one  continued  canal  with  the  stomach. 

In  the  Flamingo,  on  the  contrary,  the  dia- 
meter of  the  gullet  does  not  exceed  half  an  inch, 
being  suited  to  the  smallness  of  the  objects 
which  constitute  the  food  of  this  species. 

Besides  deglutition  the  oesophagus  is  fre- 
quently concerned  in  regurgitation ;  and  in 
the  Birds  in  which  this  phenomenon  occurs, 
the  muscular  coat  of  the  gullet  is  well  deve- 
loped, as  in  the  Ruminant  Mammalia.  The 
Raptores,  for  example,  habitually  regurgi- 
tate the  bones,  feathers,  and  other  indiges- 
tible parts  of  their  prey,  which,  in  the  lan- 
guage of  the  falconer,  are  called  '  castings/ 
A  Toucan,  which  was  preserved  some  years 
alive  in  this  country,  was  frequently  observed 
to  regurgitate  partially  digested  food,  and  after 
submitting  it  to  a  rude  kind  of  mastication  by 
its  enormous  beak,  again  to  swallow  it. 

The  oesophagus  possesses  an  external  cel- 
lular covering,  a  muscular  coat,  an  internal 
vascular  tunic,  and  a  cuticular  lining.  The 
muscular  coat  consists  of  two  layers  of 
fibres ;  in  the  external  stratum  they  are  trans- 
verse (a,  jig.  159),  in  the  internal  longitudinal 
(by  Jig.  159);  the  reverse  of  the  arrangement 
observed  in  the  human  subject. 

Ingluvies. — In  those  birds  which  are  om- 
nivorous, as  the  Toucans  and  Horn-bills,  in 
the  frugivorous  and  insectivorous  birds,  and  in 
most  of  the  Grallatores,  which  find  their  food 
in  tolerable  abundance,  and  take  it  in  small 
quantities  without  any  considerable  inter- 


318 


AVES. 


mission,  it  passes  at  once  to  the  stomach  to  be 
there  successively  digested,  and  the  gullet  pre- 
sents no  partial  dilatations  to  serve  as  a  tem- 
porary reservoir  or  macerating  receptacle.  But 
in  the  larger  Raptorial  Birds,  as  the  Eagles 
and  Vultures,  which  gorge  themselves  at  un- 
certain intervals  from  the  carcasses  of  bulky 
prey,  the  oesophagus  does  not  preserve  a  uni- 
form width,  but  undergoes  a  lateral  dilatation 
anterior  to  the  furculum  at  the  lower  part  of 
the  neck.  This  pouch  is  termed  the  ingluvies 
or  crop  (b,  Jig.  156). 

a 

Fig.  156. 


Digestive  canal  of  an  Eagle. 

In  those  birds,  again,  the  food  of  which  is 
exclusively  of  the  vegetable  kind,  as  grains 
and  seeds,  and  of  which  consequently  a  great 
quantity  must  be  taken  to  produce  the  ade- 
quate supply  of  nutriment,  and  where  the 
cavity  of  the  gizzard  is  very  much  diminished 
by  the  enormous  thickness  of  its  muscular 
coat,  the  crop  is  more  developed,  and  takes  a 
more  important  share  in  the  digestive  process. 
Instead  of  a  gradual  cylindrical  lateral  dila- 
tation of  the  gullet,  it  assumes  the  form  of  a 
globular  or  oval  receptacle  appended  to  that 
tube,  and  rests  upon  the  elastic  fascia  which 
connects  the  clavicles  or  two  branches  of  the 
furculum  together. 

In  the  common  Fowl  the  crop  is  of  large 
size  and  single  (b,fig.  157  :  I,  fig- 171),  but  in 

Fig.  157. 


the  Pigeon  it  is  double,  consisting  of  two  lateral 
oval  cavities  (b  c,Jig.  158). 

The  dilatation  of  the  oesophagus  to  form 
the  crop  is  more  gradual  in  the  Ducks 
than  in  the  Gallinaceous  birds.  The  crop  is 
wanting  in  the  Swans  and  Geese. 

The  disposition  of  the  muscular  fibres  of  the 
crop  is  the  same  as  in  the  oesophagus,  but  the 
muciparous  follicles  of  the  lining  membrane  are 
larger  and  more  numerous.  Tins  difference  is 
most  conspicuous  in  the  ingluvies  of  the  grani- 
vorous  birds,  where  it  is  not  merely  a  temporary 
reservoir,  but  in  which  the  food  is  mixed  with 
the  abundant  secretion  of  the  glands,  and  be- 
comes softened  and  macerated,  and  prepared  for 
the  triturating  action  of  the  gizzard  and  the  sol- 
vent power  of  the  gastric  secretion. 

The  change  which  the  food  undergoes  in 
the  crop  is  well  known  to  bird-fanciers.  If 
a  Pigeon  be  allowed  to  swallow  a  great  quan- 
tity of  peas,  they  will  swell  to  such  an  extent 
as  almost  to  suffocate  it. 

The  time  during  which  the  food  remains 
in  the  crop  depends  upon  its  nature.  In  a 
common  Fowl  animal  food  will  be  detained 
about  eight  hours,  while  half  the  quantity 
of  vegetable  substances  will  remain  from  six- 
teen to  twenty  hours,  which  is  one  among 
many  proofs  of  the  greater  facility  with 
which  animal  substances  are  digested.  Mr. 
Hunter  made  many  interesting  observations 
on  the  crop  of  Pigeons,  which  takes  on  a 


Fig.  158. 


secreting  function  during  the  breeding  season, 
for  the  purpose  of  supplying  the  young  pi- 
geons in  the  callow  state  with  a  diet  suitable 
to  their  tender  condition.*  An  abundant  se- 
cretion of  a  milky  fluid  of  an  ash-grey  colour, 
which  coagulates  with  acids  and  forms  curd, 
is  poured  out  into  the  crop  and  mixed  with 

*  Animal  Economy,  p.  235. 


the  macerating  grains.  This  phenomenon  is 
the  nearest  approach  in  the  class  of  Birds  to 
the  great  characteristic  function,  the  presence  of 
whose  special  apparatus,  the  mammae,  has  af- 
forded the  universally  recognized  title  of  the 
higher  division  of  warm-blooded  Vertebrata  ; 
and  the  analogy  of  the  l  Pigeon's  milk'  to  the  lac- 
teal secretion  of  the  mammalia  has  not  escaped 
popular  notice.  In  the  subjoined  figure  one  side 
of  the  crop  (/>),  shows  the  ordinary  structure  of  the 
parts,  the  other  (e\  the  state  of  the  cavity  during 
the  period  of  rearing  the  young  (fig.  158). 

The  canal  which  is  continued  from  the  in- 
gluvies  to  the  stomach  was  called  by  Hunter 
the  second  or  lower  oesophagus  ;  at  its  com- 
mencement it  is  narrower  and  more  vascular 
than  that  part  of  the  gullet  which  precedes 
the  crop,  but  gradually  dilates  into  the  first 
or  glandular  division  of  the  stomach,  which 
is  termed  the  *  proventriculus  '  (ventriculus 
tuccenturiatus,  bulbus  glandulosus,  echinus, 
injundibulum,  the  *  cardiac  cavity  '  of  Home), 
(c,  Jig.  156,  157,  166). 

In  birds  with  a  wide  oesophagus  (a,  /?g.l65), 
as  the  omnivorous  and  piscivorous  tribes,  the 
commencement  of  the  proventriculus  (e,  fig. 
165),  is  not  indicated  by  any  change  in  the  di- 
rection or  diameter  of  the  tube,  but  only  by 
its  greater  vascularity,  by  the  difference  in  the 
structure  of  the  lining  membrane,  and  by 
the  stratum  of  glands  which  open  upon  its 
inner  surface,  and  which  are  its  essential  cha- 
racteristic (c.  fig. 

'  Fig.  159. 


AVES. 


319 


Part  of  the  proventriculus  of  a 
Swan  dissected. 


159).  Hence  it  is 
by  some  compara- 
tive anatomists  re- 
garded as  a  part  of 
the  oesophagus. 

The  proventri- 
culus varies,  how- 
ever, in  form  and 
magnitude  in  dif- 
ferent birds.  In 
the  Rasores  it  is 
larger  than  the  oeso- 
phagus, but  much 
smaller  than  the 
gizzard.  In  the 

Psittacida  and  Ardeida:  (Parrot  and  Stork 
tribe)  it  is  larger  than  the  gizzard  and  of  a 
different  form.  In  the  Ostrich  the  proventri- 
culus is  four  or  five  times  larger  than  the 
triturating  division  of  the  stomach,  being  con- 
tinued down  below  the  liver,  and  then  bent  up 
upon  itself  towards  the  right  side  before  it  termi- 
nates in  the  gizzard,  which  is  placed  on  the  right 
and  anterior  part  of  this  dilatation. 

The  experiments  of  Reaumur,  Spallanzani, 
and  Hunter,  and  those  of  -Tiedemann  and 
Gmelin,  prove  that  the  secretion  of  the  pro- 
ventricular  or  gastric  glands  is  analogous  to  the 
gastric  juice  in  man  and  mammalia. 

In  the  majority  of  birds  the  gastric  follicles 
are  simple,  having  no  internal  cells,  dilated 
fund  us,  or  contracted  neck;  but  from  their 
external  blind  extremity  proceed  with  an 
uniform  diameter  to  their  internal  orifice.  This 
form  obtains  in  the  zoophagous  and  omnivorous 
birds.  In  the  Dove-tribe  the  follicles  are  of 


a  conical  shape.  In  the  Swan  they  are  tubuli- 
form  ;  in  the  Goose  and  Turkey  they  present 
internal  loculi ;  in  the  Ostrich  and  Rhea  these 
loculi  are  so  developed  that  each  gland  forms 
a  racemose  group  of  follicles,  terminating  by 
a  common  aperture  in  the  proventriculus. 

The  subjoined  figures  from  Home's  Com- 
parative Anatomy  (vol.  ii.  pi.  Ivi.)  show  the 
different  forms  of  the  solvent  or  pro  ventricular 
glands  in  different  birds. 

Fig.  160. 


Eagle. 


Gannet. 


Turkey. 


Rhea. 


Ostrich. 


The  gastric  glands  are  variously  arranged. 

Among  the  Raptores,  we  find  them  in  the 
Golden  Eagle  disposed  in  the  form  of  a  broad 
compact  belt ;  in  the  Sparrow-Hawk  this  belt 
is  slightly  divided  into  four  distinct  portions. 

In  the  Insessores  the  glands  are  generally 
arranged  in  a  continuous  zone  around  the  pro- 
ventriculus; but  in  some  of  the  Syndactyli, 
as  the  Hornbill,  the  circle  is  composed  of  the 
blending  together  of  two  large  oval  groups. 

Among  the  Scansores  the  Parrots  have  the 
gastric  glands  disposed  in  a  continuous  white 
circle,  which  is  at  some  distance  from  the  small 
gizzard.  In  the  Woodpeckers  the  glands  are 
arranged  in  a  triangular  form,  with  the  apex 
towards  the  gizzard.  In  the  Toucan  they  are 
dispersed  over  the  whole  proventriculus,  but 
are  more  closely  aggregated  near  the  gizzard ; 
the  lining  membrane  of  the  cavity  is  reticulate, 
and  the  orifices  of  the  glands  are  in  the  inter- 
spaces of  the  meshes. 

Among  the  Rasores  the  Pigeon  shows  its 
affinity  to  the  Passerine  Birds  in  having  the  gas- 
tric glands  of  a  simple  structure,  and  arranged 


320 


AVES. 


in  a  zonular  form  :  they  are  chiefly  remarkable 
for  their  large  cavity  and  wide  orifice.  In  the 
Common  Fowl  and  Turkey  the  glands  are  more 
complex,  and  form  a  complete  circle. 

In  the  Cursores  the  arrangement  of  the  glands 
is  different  in  almost  every  genus. 

In  the  Ostrich  they  are  of  an  extremely 
complicated  structure,  and  are  extended  in 
unusual  numbers  over  an  oval  space  on  the 
left  side  of  the  proventriculus,  which  reaches 
from  the  top  to  the  bottom  of  the  cavity,  and 
is  about  four  inches  broad. 

The  Rhea  differs  from  the  other  Struthious 
birds  in  having  the  solvent  glands  aggregated 
into  a  single  circular  patch,  which  occupies 
the  posterior  side  of  the  proventricular  cavity. 

In  the  Emeu  the  gastric  glands  are  scattered 
over  the  whole  inner  surface  of  the  proven- 
triculus, and  are  of  large  size ;  they  terminate 
towards  the  gizzard  in  two  oblique  lines. 

In  the  Cassowary  the  glands  are  dispersed 
over  the  proventriculus  with  a  similar  degree 
of  uniformity ;  but  they  are  smaller,  and  their 
lower  boundary  is  transverse. 

Among  the  Grallatores,  the  Marabou,  or 
Gigantic  Crane,  (Ciconia  Argala  and  Ma- 
rabou,) has  the  nearest  affinity  to  the  Rhea 
in  the  structure  and  disposition  of  the  gastric 
glands ;  they  are  each  composed  of  an  aggre- 
gate of  five  or  six  follicles,  terminating  in  the 
proventriculus  by  a  common  aperture;  and 
they  are  disposed  in  two  compact  oval  masses, 
one  on  the  anterior,  the  other  on  the  posterior 
surface  of  the  cavity.  In  the  Heron  (Ardea 
cineria)  the  solvent  glands  are  of  more  sim- 
ple structure,  and  are  more  dispersed  over  the 
proventriculus;  but  still  they  are  most  nume- 
rous on  the  anterior  and  posterior  surfaces. 
In  the  Flamingo  the  gastric  glands  are  short 
and  simple  follicles,  arranged  in  two  large  oval 
groups,  which  blend  together  at  their  edges. 

The  Natatores  present  considerable  differ- 
ences among  themselves  in  the  disposition  of 
the  solvent  glands.  In  the  Cormorant  ( Pha- 
lacrocorax  carbo)  they  are  arranged  in  two 
circular  spots,  the  one  anterior  and  the  other 
posterior;  while  in  the  closely  allied  genus 
the  Sula,  or  Gannet,  they  form  a  complete  belt 
of  great  width,  and  consequently  are  extremely 
numerous.  In  this  respect  the  Gannet,  or 
Solan  Goose,  has  a  nearer  affinity  to  the 
Pelecan,  with  which  both  birds  were  generically 
associated  by  Linnaeus. 

In  the  Sea-Gulls  the  gastric  glands  form  a 
continuous  zone  ;  and  in  the  Little  Auk  ( Alca 
Alle)  they  are  spread,  according  to  Sir  Everard 
Home,  over  a  greater  proportional  extent  of 
surface  than  in  any  other  bird  that  lives  on 
animal  food,  and  the  form  of  the  digestive 
organs  is  peculiar  to  itself.  The  cardiac  cavity 
or  proventriculus  appears  to  be  a  direct  con- 
tinuation of  the  oesophagus,  distinguished  from 
it  by  the  termination  of  the  cuticular  lining  and 
the  appearance  of  the  solvent  glands.  The  cavity 
is  continued  down  with  very  gradual  enlarge- 
ment below  the  liver,  and  is  then  bent  up  to 
the  right  side,  and  terminates  in  the  gizzard. 
The  solvent  glands  are  situated  at  the  an- 
terior or  upper  part  of  the  cavity  every  where 


surrounding  it,  but  lower  down  they  lie  prin- 
cipally upon  the  posterior  surface,  and  where 
it  is  bent  upwards  towards  the  right  side  they 
are  entirely  wanting.  In  the  graminivorous 
lamellirostral  Water-birds,  as  the  Swan,  Goose, 
&c.  the  gastric  glands  have  a  simple  elongated 
exterior  form,  but  have  an  irregular  or  cellular 
internal  surface :  they  are  closely  arranged  so 
as  to  fofin,a  complete  zone. 

In  general  the  muscular  or  pyloric  division 
of  the  stomach  immediately  succeeds  the  glan- 
dula»K)r/cardiac  division ;  but  in  some  Birds, 
as  the  Auk  and  Parrots,  there  is  an  intervening 
portioji  without  glands.  It  is  always  widely  dif- 
ferent in  structure,  and  hence  has  received  a  dis- 
tinct name,  the '  gizzard '  (gigerium,  ventriculus 
bulbosus). 

The  gizzard  is  situated  below  or  sacrad  of 
the  liver,  on  the  left  side  and  dorsal  aspect  of 
the  abdomen,  generally  resting  on  the  mass 
of  intestines ;  although,  according  to  Blumen- 
bach,  the  Nutcracker  and  Toucan,  as  well  as 
the  Cuckoo,  differ  in  having  the  gizzard  situated 
on  the  abdominal  part  of  the  cavity.  Hence 
this  peculiarity  not  being  restricted  to  the  Cuc- 
koo affords  no  explanation,  as  has  been  sup- 
posed, why  it  should  not  incubate.  In  the  Owl, 
also,  the  gizzard  adheres  to  the  membrane  cover- 
ing the  internal  surface  of  the  abdominal  muscles. 

In  all  birds  the  gizzard  forms  a  more  or  less 
lengthened  sac,  having  at  its  upper  part  two 
apertures ;  one  of  these  is  of  large  size,  com- 
municating with  the  proventriculus  (a,  fig- 161, 
162),  the  second  is  in  close  proximity  with, 
and  to  the  right  side  of  the  preceding,  leading 
to  the  duodenum  (b,  fig.  161);  below  these 
apertures  the  cavity  extends  to  form  a  cul-de- 
sac  (c,  Jig.  161,  162.)  At  the  middle  of  the 
anterior  and  posterior  parts  of  the  cul-de-sac 
there  is  a  tendon  (e,  Jig.  156,  157)  from  whicli 
the  muscular  fibres  radiate. 


Fig.  161. 


Gixzard  of  a  Swan. 


AVES. 

The  differences  in  the  structure  of  the  gizzard 
resolve  themselves  into  the  greater  or  less  extent 
of  the  tendons,  and  the  greater  or  less  thick- 
ness of  the  muscular  coat,  and  of  the  lining 
membrane. 

In  the  Ruptores  the  gizzard  (d,  Jig.  156) 
assumes  the  form  of  a  mere  membranous  cavity, 
in  accordance  with  the  animal  and  easily  di- 
gestible nature  of  their  food.  The  muscular 
coat  is  extremely  thin;  the  fibres  principally 
radiate  from  small  tendons  (<•,  Jig.  156),  and 
there  are  some  longitudinal  fibres  beneath  the 
radiating  or  external  layer. 

In  the  Rasorcs  and  lamellirostral  Natatores 
it  exhibits  the  structure  to  which  the  term  giz- 
zard can  be  more  appropriately  applied.  The 
muscular  fibres  are  distinguished  by  their 
unparalleled  density  of  texture  and  deep 
colour,  and  are  arranged  in  four  masses  ;  two 
are  of  a  hemispherical  form,  and  their  closely- 
packed  fibres  run  transversely  to  be  connected 
to  very  strong  anterior  and  posterior  tendons 
(f,  Jig.  157,  162);  they  constitute  the  sides 
of  the  gizzard,  and  are  termed  the  digastric 
muscles  or  'musculi  laterales'  (d,  Jig.  161, 
162) :  between  these,  at  the  end  of  the  gizzard, 
are  the  two  smaller  and  thinner  muscles  called 
'  musculi  intermedii'  (f,Jig.  162).  There  are 
likewise  irregular  bands  placed  about  the  cir- 
cumference of  the  gizzard. 

Fig.  1 6 1  shows  the  relative  thickness  of  the 
musculi  laterales  in  the  gizzard  of  a  Swan,  and 
fig.  162  that  of  the  musculi  intermedii  and 
tendon. 

Fig.  162. 

1 


921 


Gizzard  of  a  Swan. 

The  internal  coat  of  the  gizzard  (c,  h,Jig.  162) 
is  extremely  hard  and  thick,  and  being  of  a 
horny  or  cuticular  nature,  it  is  liable  to  be 
increased  by  pressure  and  friction,  and  as  it  is 
most  subject  to  these  influences  at  the  parts  of 
the  gizzard  opposite  the  musculi  laterales,  two 
callous  buttons  are  there  formed,  (g,  g,  fig.  1 62). 
It  is  here  that  the  fibrous  structure  of  the  lining 
membrane  can  be  most  plainly  seen : — and  it 
is  worthy  of  observation  that  the  fibres  are  not 
perpendicular  to  the  plane  of  the  muscles  but 

VOL.  I. 


oblique,  and  in  opposite  directions,  on  the  two 
sides.  Elsewhere  the  cuticular  lining  is  dis- 
posed in  ridges  and  prominences  (h,  Jig.  161, 
162),  which  vary  in  different  birds,  but  are 
pretty  constant  in  the  same  species.  Carus* 
has  recently  figured  the  gizzard  of  a  Petrel 
( Proccl/aria  glacialis),  the  lining  membrane 
of  which  is  disposed  in  a  pavement  of  small 
square  tubercles,  like  the  gastric  teeth  of  some 
Mollusca. 

The  cavity  of  the  gizzard  is  so  encroached 
upon  by  the  grinding  apparatus,  that  it  is 
necessarily  very  small,  the  two  horny  callosities 
having  their  internal  flat  surfaces  opposed  to 
one  another,  like  '  millstones/  A  crop  is  as 
essential  an  appendage  to  this  structure  as  the 
1  hopper'  to  the  mill ;  it  receives  the  food  as 
it  is  swallowed,  and  supplies  it  the  gizzard  in 
small  successive  quantities  as  it  is  wanted.f 

Between  the  stomach  of  the  carnivorous 
Eagle,  and  that  of  the  graminivorous  Swan, 
there  are  numerous  intermediate  structures,  but 
it  is  necessary  to  observe  that  the  animal  or 
vegetable  nature  of  the  food  cannotalwaysbe  pre- 
dicated of  from  the  different  degrees  of  strength 
in  the  gizzard.  Hard-coated  coleopterous  in- 
sects, for  example,  require  thicker  parietes  for 
their  due  comminution  than  pulpy  succulent 
fruits. 

In  the  submenus  Euphones,  among  the  Tana- 
gers,  the  muscular  or  pyloric  division  of  the 
stomach  is  remarkably  small  and  not  sepa- 
rated from  the  duodenum  by  a  narrow  pylorus.J 

The  parieles  of  the  gizzard,  like  those  of  other 
muscular  cavities,  become  thickened  when 
stimulated  to  contract  on  their  contents  with 
greater  force  than  usual.  In  the  Ilunterian 
collection  this  fact  is  well  illustrated  by  pre- 
parations of  the  gizzard  of  the  Sea-gull  in  the 
natural  state,  and  that  of  another  Sea-gull  which 
had  been  brought  to  feed  on  barley.  The 
digastric  muscles  in  the  latter  are  more  than 
double  the  thickness  of  those  in  the  Sea-gull 
which  had  lived  on  fish.§ 

The  immediate  agents  in  triturating  the  food 
are  hard  foreign  bodies,  as  sand,  gravel,  or  peb- 
bles. The  well-known  habit  in  the  granivorous 
birds  of  swallowing  stones  with  their  food  has 
been  very  differently  explained.  Blumenbach 
observes  that  '  Csesalpinus  considered  it  rather 
as  a  medicine  than  as  a  common  assistance  to 
digestion ;  Boerhaave,  as  an  absorbent  for  the 
acid  of  the  stomach ;  Redi,  as  a  substitute  for 
d  teeth;  Whytt,  as  a  mechanical  irritation,  adapt- 
ed to  the  callous  and  insensible  nature  of  the 
coats  of  the  stomach.'  Spallanzani  rejected  all 
supposition  of  design  or  object,  and  hazarded 
the  stupid  observation  that  the  stones  were 
swallowed  from  mere  stupidity. 

*  Tabulae  A natomiamComparativam  illustrantes, 
fol.  pars  iv.  1835. 

t  Thus  we  find  in  Parrots,  where  the  gizzard  is 
remarkably  small,  that  a  crop  is  present.  A  like 
receptacle  exists  also  in  the  Flamingo,  in  which  the 
gizzard  is  small  but  strong. 

J  Carus  ut  supra,  tab.  vi.    fig.  iv. 

§  See  Home,  Comp.  Anatomy,  vol.  i.  p.  271,  and 
Hunter,  Animal  (Economy,  p.  221,  where  it  is  re- 
lated that  a  similar  change  was  effected  by  changing 
the  food  of  a  tame  Kite. 

Y 


322 


AVES. 


Pigeons,  however,  are  known  to  carry  gravel 
to  their  young.  Gallinaceous  birds  grow  lean 
if  deprived  of  pebbles;  and  no  wonder,  since 
experiment*  shows  that  unless  the  grains  of 
corn  are  bruised,  and  deprived  of  their  vitality, 
the  gastric  juice  will  not  act  upon  or  dissolve 
them.  The  observations  and  experiments  of 
Hunter  have  completely  established  the  rationa- 
lity and  truth  of  Iledi's  opinion,  that  the  peb- 
bles perform  the  vicarious  office  of  teeth. 

Hunter  inferred  from  the  form  of  hair-balls 
occasionally  found  in  the  stomach  of  Cuckoos,t 
that  the  action  of  the  great  lateral  muscles  of 
the  gizzard  was  rotatory.  Harvey  appears  to 
have  first  investigated,  by  means  of  the  ear,  as 
it  were  in  anticipation  of  the  art  of  auscultation, 
the  actions  which  are  going  on  in  the  interior  of 
an  animal  body,  in  reference  to  the  motions  of 
the  gizzard.  He  observes,  (De  Generatione 
Animalium,  in  Opera  Omnia,  4to.  p.  208,)  "  Fal- 
conibus,  aquilis,  aliisque  avibus  ex  preda  viven- 
tibus,  si  aurem  prope  admoveris  dum  ventricu- 
lus  jejunus  est,  manifestos  intus  strepitus, 
lapillorum  illuc  ingestorum,  invicemque  colli- 
sorum  percipias."  And  Hunter  observes, 
(Animal  (Economy,  p.  198,)  "  the  extent  of 
motion  in  grindstones  need  not  be  the  tenth  of 
an  inch,  if  their  motion  is  alternate  and  in  con- 
trary directions.  But  although  the  motion  of 
the  gizzard  is  hardly  visible,  yet  we  may  be 
made  very  sensible  of  its  action  by  putting  the 
ear  to  the  sides  of  a  fowl  while  it  is  grinding 
its  food,  when  the  stones  can  be  heard  moving 
upon  one  another." 

Tiedemann  believes  that  the  muscles  of  the 
gizzard  are  in  some  degree  voluntary,  having 
observed  that  when  he  placed  his  hand  oppo- 
site the  gizzard,  its  motions  suddenly  stopped. 

The  pyloric  orifice  of  the  gizzard  is  guarded  by 
a  valve  in  many  birds,  especially  in  those  which 
swallow  the  largest  stones.  This  valve  in  the 
Ostrich  is  formed  by  a  rising  of  the  cuticle 
divided  into  six  or  seven  ridges,  which  close 
the  pylorus  like  a  grating,  and  allow  only  stones 
of  small  size  to  pass  through.  In  the  Touraco 
the  pylorus  projects  into  the  duodenum  in  a 
tubular  form.  There  is  a  double  valve  at  the 
pyloric  orifice  in  the  Gannet,  and  a  single  large 
valvular  ridge  at  the  same  part  in  the  Gigantic 
Crane.  In  this  species  and  some  other  Waders, 
as  the  Heron  and  Bittern  ;  also  in  the  Pelecan, 
and,  according  to  Cuvier,  in  the  Penguin  and 

*  Grains  of  barley,  inclosed  in  strong  perforated 
tubes,  pass  through  the  alimentary  canal  unchanged. 
Dead  meat,  similarly  introduced  into  the  gizzard, 
is  dissolved. 

t  The  hairs  of  caterpillars  devoured  by  this  bird 
are  sometimes  pressed  or  stuck  into  the  horny  lining 
of  the  gizzard,  instead  of  being  collected  into  a  loose 
ball.  They  are  then  neatly  pressed  down  in  a  regular 
spiral  direction,  like  the  nap  of  a  hat,  and  have 
often  been  mistaken  for  the  natural  structure  of  the 
gizzard.  One  of  these  specimens  exhibited  as  such 
to  the  Zoological  Society  was  sent  to  me  for  exami- 
nation, when,  upon  placing  some  of  the  supposed 
gastric  hairs  under  the  microscope,  they  exhibited 
the  peculiar  complex  structure  of  the  hairs  of  the 
larva  of  the  Tiger-moth  ( Arctia  Caja),  and  the 
broken  surface  of  the  extremity  which  was  stuck 
into  the  cuticular  lining  was  plainly  discernible. 
See  Proceedings  of  Zool,  Soc,  1834,  p.  9. 


Grebe,  there  is  a  small  but  distinct  cavity  inter- 
posed between  the  gizzard  and  intestine.  An 
analogous  structure  is  found  in  the  Crocodile. 

The  intestines  reach  from  the  stomach  to  the 
cloaca ;  in  relative  length  they  are  much  shorter 
than  in  the  mammalia.  In  the  Toucan,  for 
example,  the  whole  intestinal  canal  scarcely 
equals  twice  the  length  of  the  body,  in- 
cluding the  bill.  The  canal  is  divided  into 
small  and  large  intestines,  sometimes  by  an 
internal  valve,  sometimes  by  the  insertion  of  a 
single  coecum,  but  most  generally  by  those  of  two 
coeca,  which  are  always  opposite  to  one  another. 
In  a  few  instances  there  is  no  such  distinction. 
The  small  intestines  and  coeca  are  longest  in 
the  vegetable  feeders.  The  large  intestine  is, 
with  one  or  two  exceptions,  very  short  and 
straight  in  all  birds. 

The    course  of  the   small   intestine   varies 

somewhat  in   the  different  orders   of   Birds ; 

it  is  always  characterized  by  the  elongated  fold 

or  loop  made  by  the  duodenum,  (fj\  Jig.  163,) 

Fig.  163. 


Abdominal  viscera  of  a  Pigeon. 

which  fold  receives  the  pancreas  (q  q)  in  its 
concavity. 

In  the  Raptores  the  intestines  are  generally 
disposed  as  follows : — 

The  duodenum  forms  a  long  and  broad 
fold,  the  lower  part  of  which  is  commonly 
bent  or  doubled  upon  itself:  the  intestine  then 
passes  backwards  on  the  right  side  of  the  ab- 
domen, crosses  to  the  left,  and  is  disposed  in 
deep  folds  upon  the  edge  of  a  scolloped  mesen- 
tery ;  towards  its  termination  the  ileum  passes 
up  behind  the  stomach  and  adheres  to  it,  having 
here  but  a  narrow  mesentery;  then  passing  down 
the  posterior  part  of  the  abdomen  the  ileum 
makes  another  loose  fold  and  ends  in  the  rec- 
tum, which  is  continued  straight  to  the  cloaca.* 
In  the  Owls  the  last  fold  of  the  ileum  is  nearly 
as  long  as  the  duodenal  fold,  and  the  cceca 
adhere  to  each  side  of  the  fold. 

In  the  Diurnal  Raptores  the  intestinal  canal 

*  la  fig.  156  the  intestines  are  not  represented 
according  to  their  natural  arrangement. 


AVES. 


323 


is  only  twice  the  length  of  the  body,  except  in 
lite  fi.sh-eating  Osproy,  in  which  the  intestines 
are  very  narrow,  and  are  to  the  length  of  the 
bird  itself  as  eight  to  one. 

In  the  Insessorcs  the  scolloped  folds  of  the 
small  intestine  are  narrower  and  longer  than  in 
the  Raptores,  and  the  ileum  generally  adheres 
to  the  duodenal  mesentery  and  pancreas  in- 
stead of  to  the  stomach,  prior  to  passing  down 
to  form  its  last  fold  and  to  terminate  in  the 
rectum.  In  the  Raven  the  small  intestines  arc 
disposed  at  their  commencement  in  concentric 
folds. 

Among  the  Scansorcs  the  Cuckoo  presents 
the  following  disposition  of  the  intestinal 
canal :  after  the  usual  long  and  narrow  duo- 
denal fold,  the  ileum*  makes  a  fold  which  is 
widened  at  the  end,  it  then  forms  a  close  fold 
upon  itself,  at  the  termination  of  which  the 
rectum  commences.  In  the  Maccaw  the 
course  of  the  small  intestine  is  somewhat 
peculiar:  after  forming  the  duodenal  fold, 
it  is  disposed  in  three  distinct  packets  of 
folds  :  the  intestine,  after  forming  the  first  two, 
passes  alternately  from  one  to  the  other,  de- 
scribing shorter  folds  upon  each ;  it  then  forms 
the  third  distinct  fold,  which  is  a  long  one, 
at  the  termination  of  which  the  ileum  adheres 
closely  to  the  right  side  of  the  gizzard,  and  then 
passes  backwards  and  dilates  into  the  rectum. 

In  the  Rasores  the  Dove-tribe  have  the 
small  intestines  disposed  in  three  principal 
folds ;  the  first  is  the  duodenal  fold  (ff,  Jig. 
163);  the  second  is  along  and  narrow  fold, 
coiled  and  doubled  upon  itself,  with  the  turns 
closely  connected  together,  (k,  Jig.  163);  the 
third  is  also  a  long  fold,  which  is  bent  or 
twisted,  (k',  jig.  163.)  In  the  common  Fowl 
the  duodenum  is  disposed  in  a  long  simple 
loop ;  the  ileum  passes  towards  the  left,  and  is 
disposed  in  loose  folds  on  the  right  and  lower 
edge  of  the  mesentery ;  the  ileum  before  its 
termination  passes  up  behind  the  preceding 
folds,  and  is  accompanied  as  far  as  the  root 
of  the  mesentery  by  the  two  creca,  which 
there  open  into  the  commencement  of  the  large 
intestine. 

The  Ostrich  presents  the  most  complicated 
course  of  the  intestinal  canal  in  the  whole 
class  of  birds.  The  duodenal  fold  is  about 
a  foot  in  length,  and  the  returning  part  makes 
a  bend  upon  itself  before  it  reaches  the  py- 
lorus ;  the  intestine  then  turns  down  again 
behind  the  duodenal  folds  and  gradually  ac- 
quires a  wider  mesentery.  The  ileum  after  a 
few  folds  ascends  towards  the  left  side,  accom- 
panied by  the  two  long  cceca,  and  becomes 
again  connected  with  the  posterior  part  of  the 
duodenal  mesentery ;  beyond  which  the  cceca 
enter  the  intestine  behind  the  root  of  the  me- 
sentery, and  the  large  intestine  commences. 
This  part  differs  from  the  rectum  in  other 
biids  in  its  great  extent,  being  nearly  double 
the  length  of  the  small  intestines,  and  being 
disposed  in  folds  upon  a  wide  mesentery.  It 
terminates  by  an  oblique  valvular  aperture  in 
a  large  urinary  receptacle.  In  the  Bustard  the 

*  There  is  seldom  any  part  of  the  small  intestine 
empty  so  as  to  merit  the  name  of  jejunum. 


rectum  is  a  foot  in  length,  which  is  the  nearest 
approach  to  the  Ostrich  which  the  rest  of  the 
class  make  in  this  respect. 

The  small  intestines  in  the  Grallatorcs  are 
characterized  by  their  small  diameter  and  long 
and  narrow  folds ;  these  are  sometimes  ex- 
tended parallel  to  one  another,  as  in  the  Crane 
and  Coot;  or  folded  concentrically  in  a  mass, 
as  in  the  Curlew  and  Flamingo.  In  the  latter 
species  the  duodenal  fold  is  four  inches  in 
length ;  then  the  small  intestines  are  disposed 
in  twenty-one  elliptical  spiral  convolutions, 
eleven  descending  towards  the  rectum  and  ten 
returning  towards  the  gizzard  in  the  interspaces 
of  the  former. 

Many  of  the  Na  tat ores  present  a  concentric 
disposition  of  the  folds  of  the  small  intestines 
similar  to  the  Flamingo.  Home*  has  given 
figures  of  this  structure  in  the  intestines  of  the 
Sea-mew  (pi.  cviii.)  ;  the  Gannet  or  Solan 
Goose  (pi.  cvi.);  and  the  Goose  (pi.  cxi.). 
It  likewise  obtains  in  the  Pelecan  and  Cor- 
morant. 

The  arrangement  of  the  muscular  fibres  of 
the  intestine  is  the  same  as  in  the  oesophagus, 
the  external  layer  being  transverse,  the  internal 
longitudinal. 

The  villi  of  the  lining  membrane  manifest  an 
analogy  with  the  covering  of  the  outer  skin, 
being  generally  much  elongated,  so  as  to  pre- 
sent a  downy  appearance  when  viewed  under 
water.  There  are,  however,  great  varieties  in  the 
shape  and  length  of  the  villi.  In  the  Emeu 
they  consist  of  small  lamellae  of  the  lining 
membrane  folded  like  the  frill  of  a  shirt.  In 
the  Ostrich  the  lamellae  are  thin,  long,  and  nu- 
merous. In  the  Flamingo  they  are  short  and 
arranged  in  parallel  longitudinal  zig-zag  lines. 

In  many  birds  a  small  diverticulum  is  ob- 
served in  the  small  intestine,  which  indicates 
the  place  of  attachment  of  the  pedicle  of  the 
yolk-bag  in  the  embryo  (m,  Jig.  157).  We 
have  found  this  process  half  an  inch  in  length 
in  the  Gallinule,  and  situated  seventeen  inches 
from  the  pylorus.  In  the  Bay  Ibis  (Ibisfalci- 
nellaj  the  vitelline  ccecum  is  an  inch  in  length. 
The  birds  in  which  the  cceca  coli  have  been 
found  wanting  are  comparatively  few,  though 
such  examples  occur  in  all  the  orders.  These 
exceptions  are  most  frequent  among  the  Scan- 
sores,  in  which  the  cceca  are  absent  in  the  Wry- 
necks, the  Toucan s,  theTouracos,  the  Parrot  tribe, 
and  according  to  Cuvier  in  the  Woodpeckers.f 
In  the  Insessores  the  cceca  are  deficient  in  the 
Hornbill  and  the  Lark.  Among  the  Gral- 
latores,  we  have  found  them  wanting  in  a  Spoon- 
bill. In  the  Natatores  they  are  absent  in  the 
Cormorant.  The  Herons,  Bitterns,  and,  occa- 
sionally, the  Grebes  afford  the  rare  examples  of 
a  single  ccecum,  which  is  also  remarkably  short. 
In  the  Raptores  the  diurnal  and  nocturnal 
tribes  differ  remarkably  in  the  length  of  the 
ccoca.  They  are  each  less  than  half  an  inch  in 
length  in  the  Eagles  and  Vultures,  but  are  occa- 
sionally wanting  in  the  latter.  Cuvier  states 

*  Comparative  Anatomy,  vol.  ii. 
t    In  the  Poppinjay  ( Picusviridis,  Linn.)  we  have 
found   two  small  coeca,  so  closely  adhering  to  the 
intestine  as  easily  to  be  overlooked. 

Y  2 


324 


AVES. 


that  the  cceca  are  deficient  in  the  greater  part 
of  the  Diurnal  Raptores,  but  we  have  observed 
them  in  the  Huliatus  Albicilla,  Aquila  Chry- 
saetos,  Astur  palumbarius,  and  Buteo  nisus. 
They  seldom  exceed  the  length  above-men- 
tioned (g,Jig.  156),  and  in  the  Secretary  Vul- 
ture they  form  mere  tubercles.  In  the  Barn 
Owl  the  caeca  severally  measure  nearly  two 
inches  in  length,  and  are  dilated  at  their  blind 
extremities;  they  are  proportionally  developed 
in  the  larger  Strigida. 

In  the  Insessores  they  are  invariably  very 
short  where  present.  Among  the  Scansoriat 
Genera  which  possess  the  cceca,  these  parts 
are  found  to  vary  in  length,  measuring  in  the 
Cuckoo  and  Wattle-bird  (Glaucopis),  each 
half  an  inch ;  while  in  the  Scythrops,  or  New- 
Holland  Toucan,  the  cceca  are  each  two  inches 
Ions:,  and  moderately  wide. 

In  the  Rasores  the  cceca  present  considerable 
varieties.  In  the  Pigeons  (g,fg-  163)  they  are 
as  short  as  in  the  Insessorial  order,  and  are 
sometimes  wanting  altogether,  as  in  the  Crown- 
pigeon.  In  the  Guan  (Penelope  cristata)  each 
coecum  is  about  three  inches  in  length;  while  in 
the  Grouse  each  ccecum  measures  a  yard  long, 
being  thus  upwards  of  three  times  the  length 
of  the  entire  body.  The  internal  surface  of 
these  extraordinary  appendages  to  the  alimen- 
tary canal  is  further  increased  in  the  Grouse  by 
being  disposed  in  eight  longitudinal  folds, 
which  extend  from  their  blind  extremities  to 
within  five  inches  of  their  termination  in  the 
rectum.  We  have  always  found  the  cceca  in 
this  species  filled  with  a  homogeneous  pulta- 
ceous  matter  without  any  trace  of  the  heather 
buds,  the  remains  of  which  are  abundant  in  the 
fcecal  matter  contained  in  the  ordinary  tract  of 
the  intestines. 

In  the  Peacock  the  cceca  measure  «ach 
about  one  foot  in  length;  in  the  Partridge 
about  four  inches ;  in  the  common  Fowl  and 
other  Phasianida  the  cceca  are  each  about  one- 
third  the  length  of  the  body ;  they  commence 
by  a  narrow  pedicle,  which  extends  about  half 
their  length,  and  then  they  begin  to  dilate  into 
reservoirs  for  the  chyme  (g,fg-  157). 

In  the  Cursores  the  cceca  again  present  very 
different  degrees  of  development.  In  the 
Emeu  they  are  narrow  and  short.  In  the  Cas- 
sowary they  are  wholly  deficient;  while  in  the 
Ostrich  they  are  wide  and  upwards  of  two  feet 
in  length,  and  their  secreting  and  absorbing 
parietes  are  further  increased  by  being  pro- 
duced into  a  spiral  valve,  analogous  to  that 
which  exists  in  the  long  ccecum  of  the  Hare 
and  Rabbit. 

In  the  Grallatores  the  two  cceca  are  gene- 
rally short  where  present;  they  attain  their 
greatest  development  in  this  order  in  the  De- 
moiselle, where  the  length  of  each  ccecum  is 
five  inches ;  and  they  are  also  large  in  the  Fla- 
mingo, where  they  each  measure  nearly  four 
inches,  and  are  dilated  at  their  extremities, 
presenting  with  the  gizzard,  crop,  lamellated 
beak,  and  webbed  feet,  the  nearest  approach 
to  the  Anatida  of  the  following  order. 

In  the  Natatores  the  cceca,  where  they  are 
present,  vary  in  length  according  to  the  nature 
of  the  food,  being  very  short  in  the  fish-eating 


Penguin,  Pelecan,  Gull,  &c.  and  long  in  the 
Duck,  Goo.se,  and  other  vegetable  feeding 
Lamellirostres. 

In  the  crested  Grebe  (Podiceps  cristatus), 
Yarrell  detected  two  cceca,  each  measuring 
3-16ths  of  an  inch  in  length.  In  the  Canada 
Goose  the  same  indefatigable  observer  found 
the  cceca  each  nine  inches  in  length,  and  in 
the  White-fronted  Goose  the  same  parts  mea- 
sured severally  thirteen  inches.  They  have 
the  same  length  in  the  Black  Swan.  In  the 
Wild  Swan  the  coeca  measure  each  ten  inches 
in  length,  while  in  the  tame  species  they  are 
each  fifteen  inches  long. 

As  digestion  may  be  supposed  to  go  on  less 
actively  in  the  somnolent,  night-flying  Owls, 
than  in  the  high-soaring  Diurnal  Birds  of  Prey, 
an  additional  complexity  of  the  alimentary 
canal  for  the  purpose  of  retaining  the  chyme 
somewhat  longer  in  its  passage,  might  naturally 
be  expected;  and  the  enlarged  cceca  of  the 
Nocturnal  Raptores  afford  the  requisite  adjust- 
ment in  this  case.  For,  although  the  nature 
of  the  food  is  the  same  in  the  Owl*  as  in  the 
Hawk,  yet  the  differences  of  habit  of  life  call 
ibr  corresponding  differences  in  the  mechanism 
for  its  assimilation. 

In  the  Rasorial  Order,  where  the  nature  of 
the  food  differs  so  widely  from  that  of  the 
Birds  of  Prey,  the  principal  modification  of 
the  digestive  apparatus  obtains  in  the  more, 
complex  structure  of  the  crop,  proventriculus, 
and  above  all  the  gizzard ;  but  with  respect  to 
the  cceca,  as  great  differences  obtain  in  their 
development  as  in  the  Raptores.  Now  these 
differences  are  explicable  on  the  same  prin- 
ciple as  has  just  been  applied  towards  the 
elucidation  of  the  differences  in  the  size  of  the 
coeca  in  the  Raptores.  Where  the  difference 
in  the  locomotive  powers  is  so  great  in  the 
Dove-tribe  and  the  common  Fowl ;  where  the 
circulating  and  respiratory  systems  must  be  so 
actively  exercised  to  enable  the  Pigeon  to  take 
its  daily  flights  and  in  some  species  their  an- 
nual migrations — a  less  complicated  intestinal 
canal  may  naturally  be  supposed  with  such 
increased  energy  in  the  animal  and  vital  func- 
tions to  do  the  business  of  digestion,  than  in 
the  more  sluggish  and  terrestrial  vegetable 
feeders;  and  accordingly  we  find  that  the 
requisite  complexity  of  the  intestinal  canal  is 
obtained  by  an  increased  development  of  the 
ccecal  processes  in  them,  while  in  the  Colum- 
bidfE  the  cceca  remain  as  little  developed  as 
in  the  Insessores,  which  they  resemble  in  powers 
of  flight.  If  we  regard  the  cceca  as  excretive 
organs,  their  differences  in  the  above  orders  may 
be  in  like  manner  explained  by  their  relations 
to  the  locomotive  and  respiratory  functions. 

In  the  Cursores  the  development  of  cceca 
seems  to  have  reference  to  the  quantity  of  food, 
and  the  ease  with  which  it  may  be  obtained, 
according  to  the  geographical  position  of  the 
species.  In  the  Cassowary,  which  is  a  native 

*  The  indigestible  parts  of  the  prey  of  the  Owl 
do  not  pass  into  the  intestine,  but  are  regularly 
cast  or  regurgitated  from  the  stomach  ;  the  length 
of  the  creca  cannot,  therefore,  be  accounted  for  on 
Macartney's  supposition  of  their  being  receivers  of 
those  parts. 


AVES. 


325 


of  the  fertile  districts  of  a  tropical  country,  ve- 
getable food  of  a  more  easily  digestible  nature 
may  be  selected,  and  it  need  not  be  detained  un- 
necessarily long,  where  a  fresh  supply  can  be 
so  readily  procured.  But  in  the  Ostrich,  which 
dwells  amidst  arid  sands  and  barren  deserts, 
every  contrivance  has  been  adopted  in  the  struc- 
ture of  the  digestive  apparatus  to  extract  the 
whole  of  the  nutritious  matter  of  the  food  which 
is  swallowed. 

In  the  Grallatores,  where  no  material  dif- 
ferences of  locomotive  powers  or  means  of 
obtaining  food  exist,  the  coeca  present  in  their 
development  a  direct  relation  to  the  nature  of  the 
food,  and  are  most  developed  in  the  Gruidte. 
The  same  holds  good  in  the  Natatores. 

Why  the  increased  extent  of  intestinal  sur- 
face in  the  above  different  cases  should  be 
chiefly  obtained  by  the  elongation  of  the  coeca, 
will  appear  from  the  following  considerations. 
In  consequence  of  the  stones  and  other  foreign 
bodies  which  birds  swallow,  it  is  necessary  that 
there  should  be  a  free  passage  for  these  through 
the  intestinal  canal,  which  is  therefore  generally 
short  and  of  pretty  uniform  diameter.  In  the 
Omnivorous  birds  of  the  tropics,  as  the  Ilornbills, 
Toucans,  Touracos,  and  Parrots,  which  dwell 
among  ever-bearing  fruit-trees,  the  rapid  pas- 
sage of  the  food  is  not  inconsistent  with  the 
extraction  of  a  due  supply  of  nourishment,  but 
is  compensated  by  the  unfailing  abundance  of 
the  supply.  But  where  a  greater  quantity  of  the 
chyle  is  to  be  extracted  from  the  food,  and  where, 
from  the  nature  of  the  latter,  a  greater  proportion 
of  foreign  substances  is  required  for  its  tritura- 
tion, — while  the  advantages  of  a  short  intestinal 
tract  are  obtained,  the  chyme  is  at  the  same 
time  prevented  from  being  prematurely  expelled 
by  the  superaddition  of  the  two  ccecal  bags 
which  communicate  with  the  intestines  by 
orifices  that  are  too  small  to  admit  pebbles  or 
undigested  seeds,  but  which  allow  the  chyme  to 
pass  in.  Here,  therefore,  it  is  detained,  and 
chylification  assisted  by  the  secretion  of  the 
coecal  parietes,  and  the  due  proportion  of  nutri- 
ment extracted. 

The  large  intestine  is  seldom  more  than  a 
tenth  part  of  the  length  of  the  body,  and, 
except  in  the  Ostrich  and  Bustard,  is  continued 
straight  from  the  cceca  to  the  cloaca ;  it  may 
therefore  be  termed  the  rectum  rather  than  the 
colon.  It  is  usually  wider  than  the  small  in- 
testine, and  its  villi  are  coarser,  shorter,  and 
less  numerous.  The  rectum  (a,  fig.  164) 
terminates  by  a  valvular  circular  orifice  (6), 
in  a  more  or  less  dilated  cavity,  which  is  the 
remains  of  the  allantois,  and  now  forms  a 
rudimental  urinary  bladder,  (c  d).  The  ureters 
(A  A),  and  efferent  parts  of  the  generative  ap- 
paratus (f,  g,)  open  into  a  transverse  groove 
at  the  lower  part  of  the  urinary  dilatation, 
and  beyond  this  is  the  external  cavity  which 
lodges,  as  in  the  Reptiles  and  Marsupial  and 
Monotrematous  Quadrupeds,  the  anal  glands 
and  the  exciting  organs  of  generation.  The  anal 
follicles  in  Birds  are  lodged  in  a  conical  glan- 
dular cavity,  which  communicates  with  the  pos- 
terior part  of  the  outer  compartment  of  the  cloaca, 
and  has  obtained  from  its  discoverer  the  name  of 


Rursrt  Fabricii  (A-).  Berthold  considers  this 
part  as  a  subdivision  of  the  urinary  bladder  in 
Birds,  and  Geoffrey  St.  Ililaire  as  the  analogue 
of  Cowper's  glands. 

*.  164. 


1  Cloaca  of  the  Condor. 

Digestive  glands.  —  The  liver  is  large  in 
Birds,  and  proportionally  larger  in  the  Aquatic 
species  than  in  Birds  of  Prey.  In  the  former 

Fig.  165. 


Posterior  view  of  tlie  biliary  and  pancreatic  ducts, 
in  the  Hornbill. 


326 


AVES. 


it  bears  a  proportion  of  one-tenth,  in  some  of 
the  latter  of  one-tvventy-ninth  part  of  the  entire 
body. 

The  liver  (m  m,  jig.  163,  165)  is  situated 
a  little  above  the  middle  of  the  thoracic-abdo- 
minal cavity,  with  its  convex  surface  towards 
the  abdominal  parietes,and  its  concavity  turned 
towards  the  subjacent  viscera :  the  right  lobe 
covers  the  duodenum,  pancreas,  and  part  of  the 
small  intestines ;  the  left  lobe  covers  the  pro- 
ventriculus  and  part  of  the  gizzard;  and  the 
apex  of  the  heart  is  received  between  the  upper 
ends  of  these  principal  lobes.  The  liver  is,  as 
it  were,  moulded  upon  all  these  parts,  and  pre- 
sents corresponding  depressions  where  it  comes 
in  contact  with  them. 

It  is  generally  divided  into  two  nearly 
equal  lobes,  which  are  often  separated  for 
a  short  extent,  and  connected  together  by  a 
narrow  isthmus  of  the  glandular  substance. 
In  some  birds,  however,  as  in  the  Pigeon, 
Cormorant,  Swan,  and  Goose,  there  is  a  third, 
smaller  lobe,  situated  at  the  back  of  the  liver 
between  the  lateral  lobes,  which  from  its  situ- 
ation appears  analogous  to  the  lobulus  Spigelii 
of  Mammalia.  In  the  Common  Fowl  the  left 
lobe  is  occasionally  cleft  so  deeply  as  to  form 
two  lobes  on  that  side.  In  some  species  the 
right  lobe  exceeds  the  left  in  size ;  this  is  most 
remarkable  in  the  Bustard,  in  which  the  right 
lobe  extends  into  the  pelvis.  In  the  Eagle, 
however,  the  left  lobe  has  been  observed  to  be 
the  largest.  Each  lobe  is  invested  by  a  double 
membranous  tunic,  one  embracing  it  closely, 
the  other  surrounding  it  loosely,  like  the  peri- 
cardium of  the  heart.  They  are  formed  by 
laminae  of  the  peritoneum,  which  seems  to 
split  at  the  exterior  thin  edge  of  the  liver  into 
four  layers,  two  being  continued  upon  the 
anterior  and  posterior  surfaces  adhering  to  them, 
the  other  two  forming  the  loose  exterior  cap- 
sule. 

The  principal  ligament  of  the  liver  is  formed 
by  a  large  and  strong  duplicature  of  the  peri- 
toneum, which  divides  the  abdomen  longitu- 
dinally like  the  thoracic  mediastinum  in  Mam- 
malia. It  is  reflected  from  the  liriea  alba  and 
middle  line  of  the  sternum  upon  the  pericar- 
dium, and  passes  deeply  into  the  interspace  of 
the  lobes  of  the  liver ;  it  is  attached  to  these 
lobes  through  their  whole  extent,  and  connects 
them.below  to  the  gizzard  on  one  side  and  to  the 
duodenal  fold  on  the  other:  the  lateral  and 
posterior  parts  of  the  liver  are  attached  to  the 
contiguous  air-cells ;  and  the  whole  viscus  is 
thus  kept  steady  in  its  situation  during  the 
rapid  and  violent  movements  of  the  bird.  The 
ligament  first  described  is  analogous  to  the  fal- 
ciform ligament  of  Mammalia;  and,  although 
there  is  no  free  margin  inclosing  a  round  liga- 
ment, yet  the  remains  of  the  umbilical  vein 
may  be  traced  within  the  duplicature  of  the 
membranes  forming  the  septum.  As  the  mus- 
cular septum  between  the  thorax  and  abdomen 
is  wanting,  there  is  consequently  no  coronary 
ligament;  but  the  numerous  membranous  pro- 
cesses which  pass  from  the  liver  to  the  sur- 
rounding parts  amply  compensate  for  its  ab- 
sence. 


The  liver  is  of  a  lighter  colour  in  Birds  of 
flight  than  in  the  heavier  Water-fowl.  Each 
lobe  has  its  hepatic  artery  and  vena  portae. 
The  hepatic  arteries  are  proportionally  small, 
but  the  portal  veins  are  of  great  size,  being 
formed  not  only  by  the  veins  of  the  intestinal 
canal,  pancreas,  and  spleen,  but  also  by  the 
inferior  emulgent  and  sacral  veins.  The  blood, 
which  has  circulated  in  the  liver,  is  returned 
to  the  inferior  cava  by  two  venae  hepaticoe. 
There  are  occasionally  some  smaller  hepatic 
veins  in  addition  to  the  two  principal  ones. 
The  coats  of  the  portal  and  hepatic  veins  ap- 
pear to  be  equally  attached  to  the  substance 
of  the  liver. 

The  biliary  secretion  is  carried  out  of  the  liver 
by  two  and  sometimes  three  ducts ;  one  of  these 
terminates  directly  in  the  intestine,  and  is  a  'he- 
patic duct '  (w,  n,Jig.  165);  the  other  enters  the 
gall-bladder,  and  is  a '  cyst-hepatic  duct '  (o',Ji-g. 
1 65) ;  the  cystic  bile  is  conveyed  to  the  duo- 
denum by  a  <  cystic  duct '  (o,fig  165).  Where, 
as  in  a  few  instances,  the  gall-bladder  does  not 
exist,  both  hepatic  ducts  terminate  separately 
in  the  duodenum  (n,  n,  Jig.  163);  but  in  no 
case  is  there  a  single  ductus  communis  cho- 
ledochus  as  in  Mammalia. 

The  gall-bladder  (p,  Jig.  165)  is  situated 
near  the  mesial  edge  of  the  concave  or  under 
side  of  the  right  lobe,  and  is  commonly  lodged 
in  a  shallow  depression  of  the  liver;  but  some- 
times, as  in  the  Eagle,  Bustard,  and  Cormorant, 
only  a  very  small  part  of  the  bag  is  attached  to  the 
liver.  It  has  the  same  structure  as  in  Mamma- 
lia, manifesting  no  visible  muscular  tunic,  and 
having  its  inner  surface  delicately  reticulated. 

The  gall-bladder  is  present  in  all  the  Rap- 
tores,  Insessores,  and  Natatores.  It  is  want- 
ing in  a  great  proportion  of  the  Scansores,  as 
in  the  Genus  Rhamphastos  and  in  the  whole 
of  the  Psittacida  and  Cuculida.  Among  the 
Rasores  the  gall-bladder  is  constantly  deficient 
in  the  Columbidte.  or  Dove-tribe  alone,  in  which 
the  coeca  are  shorter  than  in  any  other  vege- 
table feeder:  (n  n,  jig.  163,  are  the  two  he- 
patic ducts  terminating  apart  from  one  another 
in  the  Pigeon.)  The  gall-bladder  is  occasion- 
ally absent,  according  to  the  French  Acade- 
micians, in  the  Guinea-fowl;  and  they  also 
found  it  wanting  in  two  out  of  six  Demoi- 
selles ( Anthropoides  Virgo).  The  gall-blad- 
der is  small  and  sometimes  absent  in  the 
Bittern :  it  is  always  wanting  in  the  Ostrich. 

The  bile,  as  before  observed,  passes  directly 
into  the  gall-bladder,  and  not  by  regurgitation 
from  a  ductus  choledochus ;  the  cyst-hepatic 
duct  arises  from  the  right  lobe,  and  is  con- 
tinued in  some  birds  along  that  side  of  the 
bag  which  is  in  contact  with  the  liver,  where  it 
penetrates  the  coats  of  the  cyst  and  terminates 
about  one-third  from  the  lower  or  posterior  end. 
In  the  Horn-bill  we  found  it  passing  over  the 
upper  end  of  the  bladder  to  the  anterior  or  free 
surface,  and  the  cystic  duct  continued  from 
the  point  where  the  cyst-hepatic  duct  opened 
into  the  bladder;  so  that  the  cystic  duct  had 
a  communicaton  both  with  the  reservoir  and 
the  cyst-hepatic  duct;  being  somewhat  ana- 
logous to  the  ductus  communis  choledochus; 


AVES. 


327 


(see  fig.  165,  where  x  represents  the  orifice  by 
which  the  bile  pusses  both  in  and  out  of  the 
gall-bladder.) 

In  the  Goose  the  cyst-hepatic  duct  termi- 
nates by  a  very  small  orifice,  surrounded 
by  a  smooth  projection  of  the  inner  mem- 
brane, which,  aided  by  the  obliquity  of  the 
duct,  acts  as  a  valve  and  prevents  any  re- 
gurgitation  towards  the  liver.  The  cystic  duct 
here  passes  abruptly  from  the  posterior  ex- 
tremity of  the  gall-bladder,  which  is  not  pro- 
longed into  a  neck.  The  duct  makes  a  turn 
round  the  end  of  the  bag,  and  is  so  closely  ap- 
plied to  it,  as  to  require  a  careful  examination  to 
determine  the  true  place  of  its  commencement. 

The  hepatic  duct  fn,  fig.  165)  arises  by  two 
branches  from  the  large  lateral  lobes  of  the 
liver,  which  unite  in  the  fissure  or  '  gates'  of 
the  gland.  Two  hepatic  ducts  have  been  found 
in  the  Curassow;  but  these  and  the  cystic 
duct  terminate  separately  in  the  duodenum. 

The  place  of  termination  of  the  cystic  and 
hepatic  duct  is  generally,  as  shown  in  Jig.  163 
and  165,  pretty  close  together  at  the  end  of 
the  fold  of  the  duodenum  ;  but  in  the  Ostrich 
one  of  the  hepatic  ducts,  which  is  very  large 
and  short,  terminates  in  the  commencement  of 
the  duodenum  about  an  inch  from  the  pylorus; 
while  the  other  enters  with  the  pancreatic  duct 
at  the  termination  of  the  duodenum. 

Both  the  cystic  and  hepatic  ducts  undergo 
a  slight  thickening  in  their  coats  just  before 
their  termination;  and  it  is  remarkable  that, 
in  some  of  the  Marsupiata,  as  the  Kangaroo, 
the  termination  of  the  ductus  choledochus  is  si- 
milarly thickened  and  glandular.  The  passage 
of  the  bile-ducts  in  birds  through  the  coats 
of  the  intestine  is  oblique,  as  in  the  Mam- 
malia, and  they  terminate  upon  a  valvular 
prominence  of  the  lining  membrane  of  the  gut. 

The  Pancreas  (q,  q,  Jig.  163,  165)  consists 
of  two  and  sometimes  of  three  distinct  por- 
tions in  Birds;  but  these  are  so  closely  ap- 
plied together  at  some  point  of  their  surface 
as  to  appear  like  one  continuous  gland.  It 
is  of  a  narrow,  elongated,  trihedral  form,  lodged 
in  the  interspace  of  the  duodenal  fold,  and 
generally  folded  upon  itself  like  the  duodenum, 
as  in  the  Hornbill  (fig.  165). 

The  structure  of  the  pancreas  is  conglome- 
rate, like  that  of  the  salivary  glands,  but  the 
ultimate  follicles  are  differently  disposed.  In 
the  salivary  glands  these  are  irregularly 
branched,  while  those  of  the  pancreas  in  Birds 
diverge  in  the  same  plane  from  digitated  and 
pinnatifid  groups.* 

The  ducts  (r  r,  Jig.  163,  165)  formed  by 
the  reiterated  union  of  the  efferent  branches 
from  the  component  follicles  of  the  pancreas 
are  in  general  two  in  number,  which  terminate 
separately  in  close  proximity  to  the  hepatic 
and  cystic  ducts ;  but  occasionally  there  are 
three  pancreatic  ducts,  as  in  the  common  Fowl, 
Pigeon,  Raven,  and  Horn-bill ;  in  which  case 
the  third  duct  commonly  terminates  at  a  dis- 
tance from  the  other  two:  in  the  Horn-bill 
it  proceeds  from  an  enlarged  lobe  of  the  pan- 

*  Mullcr  dc  Gland.  Struct.  Pen.  fol.  p.  66. 


creas   at  the  end  of  the  duodenal  fold,  and 
entering  that  part,  as  ut  ?•',  Jig.  165. 

The  Spleen  (s,  s,  Jig.  163,  165)  is  compara- 
tively of  small  size  in  Birds;  it  is  generally  of 
a  round  or  oval  figure,  but  sometimes  presents 
an  elongated  and  vermiform  shape,  as  in  the 
Sea-Gull,  or  is  broad  and  flat  as  in  the  Cor- 
morant. It  is  situated  beneath  the  liver, 
on  the  right  side  of  the  proventriculus.  It 
is,  however,  somewhat  loosely  connected  to 
the  surrounding  parts,  so  that  its  position  has 
been  differently  described  by  different  authors. 
We  have  generally  been  able  to  trace  a  pro- 
cess of  the  pancreas  passing  into  close  contact 
with  it,  and  connected  to  it  by  a  continuation 
of  vessels,  as  in  the  Horn-bill  (fig.  165,  <?,  s), 
where  it  has  been  turned  aside  to  show  the 
hepatic  and  pancreatic  ducts.  The  texture  of 
the  spleen  is  much  closer  in  Birds  than  in 
Mammalia;  but  a  minute  examination  proves 
that  the  blood  of  the  splenic  artery  is  ulti- 
mately deposited  in  cells,  from  which  the 
splenic  veins  arise.  These  veins  in  the  Swan 
and  some  other  Lamellirostres  form  a  network 
on  the  exterior  surface  of  the  spleen,  as  in  the 
Chelonian  Reptiles. 

Absorbents. — The  presumed  absence  of  ab- 
sorbent vessels  in  the  Oviparous  Vertebrata  was 
cited  by  the  supporters  of  the  theory  of  venous 
absorption  in  the  time  of  William  Hunter  as 
strong  evidence  in  favour  of  their  views ;  and 
the  same  assertion  has  again  been  repeated  in 
the  present  day  by  Majendie,*  who,  in  sub- 
sequently admittingf  the  existence  of  lympha- 
tics in  Birds,  still  contends  against  their  being 
the  exclusive  instruments  of  the  function  of 
absorption. 

Traces  of  the  lymphatic  system  in  the  pre- 
sent class  appear  to  have  been  observed  by 
SwammerdamJ  as  early  as  1676,  who  sent 
his  preparation  '  Lymphaticum  peculiare  ex  ab- 
domine  Gallinae'  to  the  Royal  Society  of  Lon- 
don; the  lacteals  were  afterwards  noticed  in 
the  Stork  by  Jacobaeus§  in  1677,  and  traces 
of  lymphatics  are  described  by  Lang||  in  1704, 
and  by  Martin  Lister^"  in  1711.  Lymphatic 
vessels  and  glands,  however,  considered  as 
such,  according  to  the  Hunterian  doctrine  of 
absorption,  were  first  undoubtedly  seen  by  John 
Hunter  in  the  neck  of  a  Swan,  and  the  lac- 
teals  of  Birds  were  afterwards  re-discovered  by 
Hewson,  who  made  the  first  attempt  to  give 
a  detailed  account  of  the  absorbent  system  in 
Birds.  Our  knowledge  of  this  system  has 
since  been  greatly  enlarged  by  the  labours 
of  Tiedemann,**  Fohmann,ff  Lauth,|J  and 
Panizza.§§ 

*  Journal  dc  Physiol.  torn.  i.  p.  47. 

t  Annales  des  Sciences  Nat.  iii.  p.  410. 

i  Birch,  Hist,  of  the  Royal  Society,  iii.  p.  312. 

j  Anat.  Ciconiae  in  Acta  Hafn.  v.  p.  247. 

|1  Physiologia  Lips.  fol.  p.  99. 

T[  Dissertatio  de  Humoribus,  1711,  8vo.  p.  228. 

**  Anat.  und  Naturgeschichte  der  Vogel,  torn.  i. 
p.  533. 

tf  Anat.  Untersuchungen  liber  die  Vcrbindung 
der  Saugadern  mit  den  Venon,  1821,  p.  136. 

$$  Annales  des  Sciences  Nat.  iii.  p.  381. 

§§  Osscrvazionc  Antropo-Zootomico  Fisiologiciie, 
fol.  Pavia,  1830. 


328 


AVES. 


The  species  in  which  the  absorbent  system 
has  been  investigated  are  the  Buzzard,  Wood- 
pecker, Turkey,  Common  Fowl,  Bittern,  He- 
ron, Stork,  Duck,  Swan,  Wild  and  Tame 
Goose,  but  especially  in  the  latter. 

The  absorbents  of  Birds  differ  from  those 
of  Mammals  in  having  fewer  valves,  which 
are  also  less  perfect,  being  so  loose  as  fre- 
quently to  permit  for  a  certain  extent  a  retro- 
grade passage  of  the  injected  fluid.  The  lacteals, 
lymphatics,  and  thoracic  ducts  have  very  thin 
parietes,  so  as  easily  to  be  ruptured,  but  they 
are  composed,  as  in  Mammals,  of  two  tunics, 
of  which  the  internal  is  the  weakest. 

The  lymph  resembles  that  of  Mammals, 
but  the  chyle  differs  essentially  in  its  trans- 
parency and  want  of  colour.  The  lacteals 
have,  however,  been  observed  to  contain  an 
opake  white  fluid  in  a  Woodpecker  that  had 
been  killed  after  swallowing  a  quantity  of  ants. 

With  respect  to  the  disposition  of  the  ab- 
sorbents, they  do  not  form  in  Birds  two  strata, 
as  in  Mammals ;  at  least  those  only  have  been 
observed  which  correspond  to  the  deep-seated 
absorbents  which  accompany  the  large  vessels. 

The  lymphatic  glands  or  ganglions  are  also 
much  less  numerous  in  Birds  than  Mammals, 
being  in  the  former  generally  restricted  in  their 
position  to  the  anterior  part  of  the  chest  or  the 
root  of  the  neck.  In  the  Penguin,  however,  a 
femoral  and  two  axillary  absorbent  glands  have 
recently  been  described.*  They  have  the  same 
structure  as  in  Man, but  are  softer.  In  other  parts 
of  the  body  the  absorbent  glands  are  replaced 
by  plexuses  of  lymphatic  vessels  surrounding 
the  principal  bloodvessels.  It  frequently  hap- 
pens, as  in  Mammalia,  that  two  large  absor- 
bents form  by  their  union  a  trunk,  which  is 
of  smaller  diameter  than  either  of  the  vessels 
composing  it. 

The  absorbents  of  Birds  terminate  principally 
by  two  thoracic  ducts,  one  on  either  side,  which 
enter  the  jugular  veins  by  several  orifices.  But 
besides  these  communications,  Tiedemann, 
Fohman,  Lauth,  and  Lippi  state  that  the  lym- 
phatic plexuses  of  the  posterior  part  of  the 
body  communicate  with  the  contiguous  sacral 
and  renal  veins.  And  Lauth  describes  several 
intercommunications  in  other  parts  of  the  body; 
these,  however,  are  denied  by  Panizza,  whose 
careful  and  elaborate  researches  seem  to  prove 
that  the  passage  of  the  lymph  into  the  venous 
system  takes  place  in  Birds  only  in  two  places 
in  the  pelvic  region  in  addition  to  those  by  the 
two  thoracic  ducts  in  the  neck. 

The  lymphatics  of  the  foot  unite  to  form 
the  vessels  which  are  found  running  along  the 
sides  of  each  toe  (1,  \,fig.  166).  In  the  Pal- 
mipedes there  are  anastomosing  branches  which 
pass  from  the  lateral  vessel,  of  one  toe  to  that 
of  the  adjoining  toe,  forming  arches  in  the 
uniting  web  (2).  These  branches  form  a  small 
plexus  (3)  at  the  anterior  part  of  the  digito- 
metatarsal  joint,  from  which  three  or  four 
lymphatics  are  continued.  The  anterior  and 
internal  branches  (4)  accompany  the  blood- 
vessels, and  form  a  network  around  them ; 
the  posterior  and  external  branches  (5)  receive 

*  Reid,  iu  Proceedings  of  Zool.  Soc.  Sept.  1835. 


Fig.  166. 


Absorbents  of  a  Goose.* 

the  lymphatics  of  the  sole  of  the  foot,  then 
ascend  along  the  metatarsus,  and  form  at  its 
proximal  articulation  a,  close  network  (6);  all 
the  vessels  then  ascend  the  tibia,  forming  a 
plexus  (7)  around  it  as  far  as  the  middle  of  the 
leg;  then  they  unite  into  two  branches,  of 
which  the  smaller  passes  along  the  anterior 
part  of  the  depression  between  the  tibia  and 
fibula  as  far  as  the  knee-joint,  where  it  joins 
the  other  branch  which  accompanies  the  blood- 
vessels. The  trunk  formed  by  the  union  of 
the  two  preceding  branches  accompanies  the 
femoral  vessels,  forming  plexuses  in  its  course 

*  From  Lauth 's  Monograph,  Annalesdes  Sciences 
Nat.  t.  iii.  pis.  23  and  25. 


AVES. 


329 


(8),  which  receive  tributary  absorbents  from  the 
surrounding  muscles,  and  a  large  branch  (9) 
corresponding  to  the  deep-seated  femoral  vessels. 

The  ilkic  trunk  (10)  accompanies  the  great 
femoral  vein  into  the  abdomen,  which  it  enters 
anterior  to  the  origin  of  the  pubis ;  it  there 
receives  branches  from  the  lateral  parts  of 
the  pelvis  (11)  and  afterwards  separates  into 
two  divisions. 

The  posterior  division  receives  some  lym- 
phatics from  the  anterior  lobes  of  the  kidneys, 
and  those  of  the  ovary  or  testicles;  it  com- 
municates anteriorly  with  a  branch  from  the 
absorbents  which  surround  the  great  mesenteric 
artery,  and  posteriorly  with  large  vesicular 
plexuses  or  receptacles  (12,  13)  surrounding 
the  aorta  and  its  branches,  and  which  receives 
the  lymphatics  from  the  renal  plexus,  and  those 
accompanying  the  arteria  sacra  media  (14). 

The  sacral  or  pelvic  plexiform  vesicles  of 
the  lymph  are  described  by  Panizza  in  the 
(loose  as  being  two  in  number,  situated  in  the 
posterior  region  of  the  body,  in  the  angle 
between  the  tail  and  the  thigh.  F.ach  vesicle 
is  little  more  than  half  an  inch  long  and  a 
quarter  of  an  inch  broad,  and  is  shaped  some- 
what like  a  kidney-bean.  Panizza  laid  them 
bare  in  several  living  Geese  and  punctured 
them,  upon  which  the  lymph  issued  in  con- 
siderable quantity,  and  coagulated  into  a  jelly 
like  the  lymph  from  ordinary  lymphatics. 
Fluids  thrown  into  the  lymphatics  leading  to 
the  vesicles  not  only  filled  these  cavities,  but 
passed  from  them  into  the  veins.  There  are 
analogous  vesicles  in  the  Reptiles,  which  are 
endowed  with  a  pulsatile  power,  and  propel 
their  contents  into  the  pelvic  veins  per  sultum  ; 
but  the  recent  researches  of  Miiller  (Archiv. 
fur  Physiol.  1834,  p.  300)  show  that  the  pelvic 
lymphatic  vesicles  of  Birds  are  not  endowed 
with  a  power  of  motion  like  that  belonging  to 
those  of  Reptiles,  he  having  satisfied  himself, 
by  repeated  examination  of  the  living  Goose, 
that  the  alternate  contraction  and  dilatation  of 
these  vesicles  in  this  animal,  which  Panizza 
conceived  to  depend  on  an  automatic  power 
within  them,  corresponds  exactly  with  the 
motions  of  respiration,  and  no  longer  continues 
when  they  are  interrupted.* 

The  anterior  division  of  the  femoral  lym- 
phatic trunk  (16)  accompanies  the  aorta,  upon 
which  it  forms  a  plexus  with  the  branch  of 
the  opposite  side,  and  with  the  intestinal  ab- 
sorbents (15). 

These  vessels,  which  from  the  transparency 
of  their  contents  can  scarcely  be  termed  with 
propriety  t  lacteals,'  commence  from  a  plexi- 
form continuous  network  situated  between  the 
mucous  and  muscular  coats  of  the  intestine; 
they  are  larger  here  than  when  they  quit  the 
intestine  to  pass  upon  the  mesentery.  They 
accompany  the  branches  of  the  superior  mesen- 
teric artery,  there  being  many  absorbents  for 
one  artery,  which  by  their  anastomoses  form 
plexuses  surrounding  the  bloodvessels.  Before 
reaching  the  aorta,  these  absorbents  commu- 
nicate with  the  inferior  or  posterior  division  of 

*  Sec  Allen  Thompson,  in  Ediiib.  Mcd.  and 
Surg.  Jouin.  No.  125. 


the  femoral  trunk,  and  with  the  absorbents  of 
the  ovary  or  testicles,  after  which  they  pass 
upon  the  aorta  (16,  17),  where  they  receive 
the  lymphatics  of  the  pancreas  and  duodenum, 
and  terminate  by  uniting  around  the  cceliac 
axis  (18)  with  the  lymphatics  of  the  liver,  the 
proventriculus  (r),  the  gizzard,  and  the  spleen, 
forming  a  considerable  plexus,  from  which, 
according  to  Lauth,  it  is  by  no  means  rare 
to  see  branches  passing  to  terminate  in  the 
surrounding  veins. 

The  aortic  plexus  (19),  which  may  be 
regarded  as  analogous  to  the  receptaculum 
chyli,  always  gives  origin  to  two  thoracic 
ducts  (20,  20)  of  varying  calibre,  but  often, 
as  in  the  Goose,  exceeding  a  line  in  diameter. 
They  are  situated  at  their  origin  behind  the  ceso- 
phagus  («)  and  in  front  of  the  aorta  (6)  ;  they 
advance  forwards,  diverging  slightly  from  each 
other,  pass  over  the  lungs  (ww),  from  which  they 
receive  some  lymphatics,  and  terminate  seve- 
rally, after  being  joined  by  the  lymphatics  of 
the  wing,  in  the  jugular  vein  of  the  same  side. 
The  left  thoracic  duct,  before  entering  the  vein, 
receives  the  trunk  of  the  lymphatics  of  the  left 
side  of  the  neck ;  the  right  thoracic  duct  re- 
ceives only  a  branch  of  those  of  the  same  side. 

The  lymphatics  of  the  wing  follow  the 
course  of  the  brachial  artery,  forming  a  plexus 
around  it,  especially  at  the  elbow-joint.  Their 
principal  trunk,  to  which  all  the  collateral 
branches  are  united  about  the  upper  third  of 
the  humerus,  is  here  of  large  size,  but  its  di- 
ameter soon  begins  to  be  diminished,  and  it  is 
very  small  at  the  head  of  the  humerus.  When 
it  reaches  the  parietes  of  the  chest,  it  receives 
two  or  three  large  lymphatics  from  the  pectoral 
muscles,  and  a  branch  which  accompanies  the 
brachial  plexus.  Soon  after  a  small  lym- 
phatic gland  is  sometimes  formed  on  the  trunk, 
which  lastly  unites  with  the  thoracic  duct  of 
its  own  side. 

The  lymphatics  of  the  head  accompany  the 
branches  of  the  jugular  vein,  and  are  readily  dis- 
cerned upon  those  which  are  situated  between  the 
ramiof  thelower  jaw.  They  form,  by  uniting  with 
the  cervical  absorbents,  two  lateral  branches  on 
each  side,  which  accompany  the  corresponding 
jugular  vein,  being  situated,  one  in  front,  the 
other  behind  that  vessel.  These  lymphatics 
communicate  together,  at  the  anterior  and  pos- 
terior parts  of  the  neck,  by  transverse  or  ob- 
lique branches.  They  receive  in  their  progress 
absorbents  from  the  muscles,  and  from  the 
peculiar  glands  which  are  seen  beneath  the 
skin  of  the  neck.  The  internal  branch  on  the 
left  side  receives  also  a  considerable  absorbent 
from  the  oesophagus.  At  the  lower  part  of  the 
neck  both  branches  receive  a  notable  branch 
which  accompanies  the  carotid  arteries,  and 
a  little  further  on  they  form  on  each  side  a 
lymphatic  gland  situated  on  the  jugular  vein. 
On  the  right  side  the  trunk  of  the  cervical 
lymphatics  terminates  in  the  jugular  vein,  after 
having  furnished  a  communicating  branch  with 
the  thoracic  canal  of  that  side ;  on  the  left  side 
it  terminates  at  once  in  the  corresponding  tho- 
racic duct. 

Vascular  system.  —  Heart. — The  heart  in 
Birds  is  divided,  as  in  Mammals,  into  four 


330 


AVES. 


distinct  cavities,  which  have  the  same  relations 
to  each  other,  and  impress  the  same  course 
on  the  circulating  fluid.* 

The  form  of  this  viscus  is  always  that  of  a 
cone,  sometimes  wide  and  short,  as  in  the 
Ostrich  and  Crane ;  sometimes  more  elongated, 
as  in  the  Emeu  (jig.  167)  and  Vulture;  or 
still  more  acute,  as  in  the  Curlew,  Common 
Fowl,  &c. 

Its  situation  is  more  anterior  and  mesial  than 
in  Mammalia,  and  its  axis  is  always  parallel 
with  the  axis  of  the  trunk.  It  is  not  contained 
with  the  lungs  in  an  especial  cavity,  but  its 
apex  is  lodged  between  the  lobes  of  the  liver ; 
the  diaphragm  not  being  so  far  developed  as 
to  separate  the  chest  from  the  abdomen. 

As  the  lungs  are  confined  to  the  dorsal  part 
of  the  chest,  the  whole  of  the  anterior  surface 
of the  pericardium  is  exposed  when  the  sternum 
of  the  bird  is  removed.  The  pericardium  is  thin, 
but  of  a  firm  texture,  and  adheres  by  its  ex- 
ternal surface  to  the  surrounding  air-cells.  It 
is  of  considerable  size,  and  commonly  prolonged 
for  some  way  between  the  lobes  of  the  liver. 

The  auricles  of  the  heart  in  Birds  have  not 
externally  such  distinct  appendices  as  in  Mam- 
mals. The  right  auricle  is  much  larger  than 
the  left;  it  is  more  distinctly  divided  internally 
into  a  sinus  (d,  jig.  167)  and  auricle  proper 

Fig.  167. 


Heart  of  the  Emeu. 

than  in  Mammals,  and  these  parts  are  separated 
by  a  more  complete  valvular  structure ;  in  which 
respect  Birds  bear  a  closer  analogy  to  Reptiles. 
Three  veins  terminate  in  the  sinus,  there 
being  in  Birds  always  two  superior  cavae, 
as  in  Reptiles.  The  right  superior  cava  (a), 
which  returns  the  blood  from  the  right  wing 
and  right  side  of  the  neck,  terminates  in 
the  upper  and  anterior  part  of  the  sinus ;  the 
left  superior  cava  (b,  b)  winds  round  the  pos- 
terior part  of  the  left  auricle  to  open  into  the 

*  The  blood  of  Birds  differs  from  that  of  the 
other  Vertebrate  classes  in  the  greater  number  of 
globules,  and  from  that  of  Mammalia  in  their 
form,  which  is  oval  instead  of  round.  Sec  BLOOD. 


lower  part  of  the  sinus;  just  before  its  termination 
it  receives  the  coronary  vein,  so  that  this  does 
not  open  separately  into  the  auricle  as  in  most 
Mammalia.*  The  inferior  cava  (c)  terminates 
in  the  sinus  just  above  the  orifice  of  the  left  su- 
perior cava,  and  a  semilunar  valvular  fold  (A), 
analogous  to  that  of  the  coronary  vein  in  man, 
is  extended  forwards  between  these  orifices  so 
as  to  separate  them,  and  afford  a  protection  to 
the  mouth  of  the  left  superior  cava,  in  addition 
to  that  which  it  derives  in  common  with  the 
other  veins  from  the  larger  valves  at  the  mouth 
of  the  sinus. 

The  disposition  of  the  valves  between  the 
sinus  and  auricle  seems  more  especially  des- 
tined to  prevent  regurgitation  into  the  sinus, 
when  the  pulmonary  circulation  may  be  im- 
peded, rather  than  to  impress  any  definite 
course  on  the  current  of  blood  flowing  through 
the  auricle,  as  Cuvier  supposes.  A  strong 
oblique  semilunar  muscular  fold  (g)  commences 
in  the  Emeu  by  a  band  of  muscular  fibres 
running  along  the  upper  part  of  the  auricle, 
and  expanding  into  a  valvular  form  extends 
along  the  posterior  and  left  side  of  the  sinus, 
terminating  at  the  lower  part  of  the  fossa  oval  is 
(i).  A  second  semilunar  muscular  valve  (_/), 
of  equal  size,  extends  parallel  with  the  preceding 
along  the  anterior  border  of  the  orifice  of  the 
sinus,  its  lower  extremity  being  fixed  to  the 
smooth  floor  of  the  auricle,  its  upper  extremity 
being  continued  into  a  strong  muscular  column 
running  parallel  to  the  one  first  mentioned 
across  the  upper  and  anterior  part  of  the 
auricle,  and  giving  off  from  its  sides  the  greater 
part  of  the  musculi  pectinati.  From  this  struc- 
ture it  results  that  the  more  powerfully  the 
musculi  pectinati  act  in  overcoming  the  ob- 
stacle to  the  passage  of  the  blood  from  the 
auricle  to  the  ventricle,  the  closer  will  the  valves 
be  drawn  together,  and  the  stronger  will  be 
the  resistance  made  by  them  to  the  regurgitation 
of  the  blood  from  the  auricle  into  the  sinus. 
The  parietes  of  the  auricle  in  the  interspaces  of 
the  muscular  fasciculi  are  thin  and  transparent, 
consisting  in  many  parts  only  of  the  lining  mem- 
brane of  the  cavity  and  the  reflected  layer  of  the 
pericardium  blended  together.  Thefossa  ovalis 
(i)  is  a  deep  depression  situated  behind  the  pos- 
terior semilunar  valve,  which,  we  may  observe, 
bears  nearly  the  same  relation  to  the  fossa  as 
the  annulus  ovalis  in  the  human  heart.  The 
membranous  septum  closing  the  foramen  ovale 
is  complete  and  strong,  but  thin  and  semi- 
transparent.  The  appendix  auricula  (V)  is  the 
most  muscular  part  of  the  cavity ;  it  does  not 
project  freely  in  front  of  the  great  vessels 
arising  from  the  ventricles,  but  is  tightly  tied 
down  to  them  by  the  reflected  layer  of  the 
pericardium.  The  auriculo-ventricular  orifice 
is  an  oblique  slit  (k,fig.  169 ;  a  bristle  is  passed 
through  it  in  Jig.  167).  The  manner  in  which  re- 

*  In  those  Mammalia  which  approach  nearest  to 
the  oviparous  vertebrata,  as  the  Monotremata  and 
Marsupiata,  there  are  always  two  superior  cavae,  as 
in  Birds  and  Reptiles  ;  a  similar  structure  obtains 
in  some  of  the  Rodentia,  as  the  Porcupine  ;  and 
also  occurs  in  the  Elephant.  In  all  these  cases  we 
have  found  that  the  coronary  vein  terminates  in 
the  left  superior  cava. 


AVES. 


331 


gurgitation  by  this  orifice  is  prevented  is  one 
of  the  chief  peculiarities  in  the  heart  of  Birds. 

Fig.  168. 


second  muscular  valve,  which,  though  small,  is 
Fig.  169. 


Ventricles  of  the  heart  of  a  Swan. 

The  right  ventricle  (k,fg.  1 68)  is  a  narrow  trian- 
gular cavity,  applied  as  it  were  to  the  right  and 
anterior  side  of  the  left  ventricle,  but  not  ex- 
tending to  the  apex  of  the  heart.  The  parietes 
are  smooth,  and,  except  at  the  septum  ventri- 
culorum,  they  are  of  pretty  uniform  thickness, 
but  weaker  in  comparison  to  those  of  the  left 
ventricle  than  in  Mammalia.  A  number  of 
short  fleshy  columns  extend  from  the  septum 
to  the  free  parietes  of  the  ventricle  at  the  angle 
of  union  of  these  two  parts,  leaving  deep  cells  be- 
tween them ;  a  strong  fleshy  column  (m,jig.  169) 
also  extends  from  the  right  side  of  the  base  of 
the  pulmonary  artery  to  the  upper  extremity  of 
the  auriculo-ventricular  valve;  but  these  are 
the  only  columns  cornea  in  the  right  ventricle ; 
there  being  none  of  a  pyramidal  form  pro- 
jecting into  the  cavity,  nor  any  chorda  ten- 
dineae.  The  principal  valve  which  guards  the 
auricular  aperture  is  a  strong  muscular  fold 
(I,  fig.  167,  168,  169),  nearly  as  thick  as  the 
walls  of  the  ventricle  itself,  extending  from  the 
fleshy  column  above  mentioned  obliquely  down- 
wards and  backwards  to  the  angle  formed  be- 
tween the  septum  cordis  and  the  wall  of  the 
ventricle  at  the  lower  and  posterior  part  of  the 
cavity.  The  free  rounded  edge  of  this  muscular 
valve  is  turned  towards  the  convex  projection 
made  by  the  septum,  and  must  be  forcibly  ap- 
plied to  this  part  during  the  systole  of  the 
ventricles,  so  that,  while  all  reflux  into  the 
auricle  is  prevented,  additional  impulse  is  given 
to  the  flow  of  blood  through  the  pulmonary 
artery;  the  muscular  parietes  of  the  ventricle 
being  thus  complete  at  every  part  except  at  the 
orifice  of  the  artery. 

The  small  muscular  column  (m,jig.  169)  at 
the  upper  part  of  the  auricular  orifice  is  analo- 
gous in  its  position  to  the  single  valve  which 
guards  the  corresponding  orifice  in  Reptiles; 
in  which  class  the  Croeodiles  alone  present  a 


Section  of  the  ventricles,  Pelecan, 

analogous  in  its  position,  and  evidently  a  rudi- 
mental  form  of  the  large  muscular  valve  in 
Birds. 

The  right  ventricle  is  remarkable  for  the 
smoothness  and  evenness  of  its  inner  surface. 
The  pulmonary  artery  is  provided  at  its  origin 
with  three  semicircular  valves  (n,fig.  169).  It 
divides,  as  usual,  into  two  branches  (n,  n,Jig. 
168),  one  for  each  lung ;  the  right  branch  passes 
under  the  arch  of  the  aorta. 

The  aerated  blood  is  returned  from  the  lungs 
by  two  veins  which  open  into  the  back  part 
of  the  left  auricle;  a  strong  semilunar  ridge, 
which  is  hardly  sufficiently  produced  to  be 
called  a  valve,  divides  the  cavity  of  the  auricle 
in  which  the  veins  terminate  from  the  mus- 
cular part  or  appendix.  The  fleshy  columns 
are  very  numerous  and  complicated  in  this  part 
of  the  auricle,  which  is  closely  tied  down  to 
the  ventricle  by  the  serous  layer  of  the  pericar- 
dium and  dense  cellular  tissue. 

The  left  ventricle  (o^fig.  168, 169)  is  an  elon- 
gated conical  cavity,  the  parietes  of  which  are 
three  times  as  thick  as  those  of  the  right  ventricle, 
and  exhibit  strongfleshy  columns  extending  from 
the  apex  towards  the  base;  two  of  the  largest 
of  these  columns  present  in  the  Emeu  a  short 
convex  eminence  towards  the  auriculo-ventri- 
cular orifice  (r,^.169),  and  give  off  short  thick 
tendons  to  the  margin  and  ventricular  surface 
of  two  membranous  folds,  (p,  q,fig.  168, 169) 
which  correspond  to  the  mitral  valve  in  Mam- 
malia. Of  these  valves,  the  one  next  the  aorta  (</) 
corresponds  to  the  single  valve  which  guards 
the  auricular  opening  in  the  heart  of  Reptiles, 
and  is  most  developed  in  Birds;  the  oppo- 
site valve  is  of  much  less  size.  In  many  Birds 
the  chordae  tendineae  pass  from  the  valves  at 
once  to  the  parietes  of  the  ventricle,  and  are 
not  attached  to  columnse  carneae.  The  surface 
of  the  ventricle  formed  by  the  septum  is  smooth 
from  the  orifice  of  the  aorta  down  to  the  apex 
of  the  heart.  The  aorta  is  provided,  as  in  Mam- 
malia, with  three  semicircular  valves.  In  Rep- 
tiles, even  in  the  Crocodile,  the  great  arteries 
arising  from  the  ventricles  are  each  provided 
with  two  valves  only. 

We  have  observed  that  in  general  the  valves 
at  the  base  of  the  pulmonary  artery  were 
thicker  and  stronger  than  those  at  the  origin 
of  the  aorta,  and  our  lamented  and  talented 
friend  Mr.  Home  Clift  discovered  some  years 


332 


AVES. 


ago  that  the  extremities  of  the  semilunar  valves 
in  Birds  were  connected  to  small,  firm,  and 
sometimes  ossified  styles  imbedded  in  the  fibrous 
co;it  of  the  vessels. 

The  arrangement  of  the  muscular  fibres  of  the 
ventricle  in  Birds  is  such  that  the  right  ventricle 
appears  to  be  formed  by  a  partial  secession  of 
the  outer  from  the  inner  layers  of  the  parietes 
of  the  left  ventricle  at  the  anterior  and  right 
side  of  that  cavity.  See  the  transverse  section, 
(Jig.  169.) 

Arteries.— the  distribution  of  the  arterial 
system  has  been  described  in  a  general  man- 
ner by  Cuvier,  Tiedemann,  and  Nitzsch,  and 
has  subsequently  been  very  completely  elu- 
cidated by  Barkow  in  the  12th  Volume  of 
Meckel's  Archives  of  Physiology  ;  where  the 
different  varieties  which  various  species  of  birds 
present  in  the  course  of  individual  arteries 
are  laboriously  pointed  out.  Tn  our  own  dis- 
sections we  have  been  guided  by  the  excellent 
description  long  ago  given  by  Dr.  Macartney, 
(Art.  Birds,  llees'  Cyclopaedia)  which  we  shall 
here  give  verbatim,  with  some  general  remarks 
and  additional  particulars  afforded  by  the  re- 
searches of  Barkow  and  our  own  dissections. 
The  description  will  be  aided  by  the  subjoined 
beautiful  figure  taken  from  Barkow's  Mono- 
graph (Jig.  170). 

The  arterial  system  in  Birds  is  essentially 
distinguished  from  that  of  Mammals  by  the 
following  differences  : — 

1st.  The  division  of  the  aorta  into  three 
principal  branches,  almost  immediately  at  its 
origin. 

2d.  The  course  of  the  arch  of  the  aorta  over 
the  right  instead  of  the  left  bronchus  to  become 
the  descending  aorta. 

3d.  The  origin  of  the  arteries  of  the  posterior 
extremities,  which  do  not  come  off  from  a  single 
branch  analogous  to  the  external  iliac  of  Mam- 
malia, but  from  two  arteries  which  are  detached 
successively  from  the  aorta  at  a  great  distance 
from  each  other,  and  pass  from  the  pelvis  by 
two  separate  apertures. 

The  arteries  of  the  systemic  circulation 
proceed,  Macartney  observes,  "from  a  single 
trunk,  which  arises  from  the  left  ventricle  of 
the  heart.  This  trunk,  the  aorta,  (1,  fig.  170) 
is  so  short  that  it  is  concealed  by  the  other 
parts  on  the  basis  of  the  heart,  and  is  only 
brought  into  view  after  the  reflections  of  the 
pericardium  and  the  adjoining  vessels  are  de- 
tached by  dissection.  It  is  from  thence  that 
as  the  parts  are  commonly  beheld,  there  appear 
to  be  three  great  arteries  issuing  together  from 
the  middle  of  the  heart,  which  are  the  primary 
branches  into  which  the  aorta  is  divided.  The 
first  branch  is  to  the  left  side,  and  after  it  is 
sent  off,  the  trunk  affects  to  turn  over  the  au- 
ricle before  it  gives  the  branch  of  the  right 
side;  these  two  branches  pass  in  a  curved 
manner  from  the  heart  towards  the  axilla  in 
the  form  of  horns,  and  each  is  analogous  to 
the  arteria  innominata  of  the  human  subject, 
so  that  instead  of  one  there  may  be  reckoned 
two  arteria  innominata  in  Birds  (t  t,  Jig.  167, 
1 68).  After  these  branches  are  parted  with,  the 
arterial  trunk  (s,  fg.  167,  168,  2,  Jig.  170)  is 
continued  over  the  auricles,"  and  the  right  bron- 


Fig.  170. 


Arteries  of  the  Trunk,  Grebe. 

chus,  "  and,  on  reaching  the  back  part  of  the 
heart,  becomes  the  descending  aorta. 

"  The  arteria  innominata  (3)  first  sends  off 
the  common  trunk  of  the  carotid  and  vertebral 
arteries  (4),  which  before  its  division  gives  off 
one  or  two  small  branches ;  one  of  these  runs 
down  upon  the  lungs  in  company  with  the  par 
vagum,  and  appears  to  supply  branches  to  the 
aponeurosis  of  the  lungs,  and  the  air-cells  at 
the  upper  part  of  the  thorax;  the  other  branch, 
aft^r  supplying  the  lymphatic  gland  of  the 
neok  with  several  small  arteries,  ascends  upon 
the  side  of  the  oesophagus,  to  which,  and  the 
inferior  larynx,  the  divisions  of  the  trachea, 
and  to  the  parts  and  integuments  of  the  side  of 
the  neck,  its  branches  are  distributed,  anasto- 
mosing with  the  superior  cesophageal  and  tra- 
cheal  arteries.  This  branch  is  often  not  sent 
off  until  the  trunk  divides  into  the  vertebral  and 
carotid,  in  which  case  it  comes  from  the  latter 
artery.  Sometimes  in  the  Duck,  the  supra- 
scapular  artery,  which  is  usually  divided  from 
the  vertebral,  is  a  branch  of  the  common  trunk." 

The  carotid  arteries  (4,  4,  Jig.  170,  u  u,  Jig. 
167)  are  frequently  of  unequal  size;  in  the  Dab- 
chick  the  left  is  by  much  the  largest;  in  the 
Emeu  we  found  it  the  smallest.  "  In  the  Com- 
mon Fowl,  each  carotid,  after  parting  from  the 
vertebral  artery  (6),  proceeds  to  the  middle  of  the 
neck  and  soon  disappears ;  becoming  covered  by 
the  muscles  of  the  anterior  part  of  the  neck,  and 
entering  the  canal  formed  by  the  inferior  spinous 


AVES. 


333 


processes  of  the  cervical  vertebrae,  within  which 
it  lies  hidden,  and  in  close  contact  with  its  fellow 
of  the  other  side,  to  very  near  the  head."  In 
the  Bittern  the  two  carotids  are  situated  one 
behind  the  other,  and  adhere  so  intimately  to- 
gether in  this  situation  that  they  have  been 
erroneously  described  as  a  single  trunk. 

"  The  carotid  artery  emerges  from  between 
the  muscles  of  the  neck,  at  about  the  third  or 
fourth  vertebra  from  the  head  (9) ;  and  after 
giving  a  branch  (10, 11),  Arteria'  cutancte  colli 
laterules,  downwards,  to  the  lateral  muscles  and 
integuments  of  the  neck,  it  runs  along  the  outer 
edge  of  the  rectus  major  anticus  muscle  to  behind 
the  angle  of  the  jaw,  where  it  divides  into  its 
several  branches. 

"  An  artery  (arteria  occipitalis)  first  goes  off 
posteriorly,  which  passes  a  little  forwards  under 
the  branch  of  the  os  hyoides,  and  after  sending 
some  blood  to  the  muscles  of  the  neck,  makes 
a  turn  backwards,  enters  the  foramen  in  the 
transverse  process  of  the  second  vertebra,  and 
terminates  by  a  singular  anastomosis  in  the 
vertebral  artery.* 

"  The  next  branch  is  analogous  to  the  internal 
carotid;  it  goes  forward  also  under  the  os 
hyoides,  and  passes  behind  the  muscles  of  the 
jaws  close  upon  the  lower  part  of  the  skull,  at 
which  place  it  sends  a  branch  upwards,  which 
appears  to  penetrate  the  bones  on  the  outside 
of  the  ear,  and  supply  the  organ  of  hearing, 
sends  a  branch  into  the  skull  and  another 
through  the  articulation  of  the  jaw,  to  unite 
with  the  ophthalmic,  and  contribute  to  the 
plexus  at  the  back  of  the  orbit  (Rete  oph- 
thalmicum  of  Barkow).  The  internal  carotid 
then  enters  an  osseous  canal,  which  runs 
along  the  basis  of  the  cranium,  between  the 
tables  of  the  bone ;  and  at  the  lower  and 
back  part  of  the  orbit,  the  artery  receives  a 
remarkable  anastomosing  branch  of  the  inter- 
nal maxillary,  which  almost  equals  in  size  the 
carotid  itself,  and  these  two  vessels  produce 
by  their  union  one  which  passes  almost  directly 
into  the  cranium  at  the  usual  place  for  the 
entrance  of  the  carotid  artery.  This  vessel 
forms  within  the  skull  an  anastomosis  similar 
to  the  circle  of  Willis;  but  the  branch  which 
occupies  the  place  of  the  basilar  artery  is  very 
small,  and  appears  to  be  furnished  entirely 
from  the  anastomosis  of  the  carotids,  and  do- 
signed  only  to  supply  the  medulla  oblongata 
and  spinal  marrow.  The  branches  of  the  in- 
ternal carotid  are  thickly  spread  in  an  arborescent 
form  upon  the  surfaces  of  the  brain  ;  some  on 
the  outside  and  others  on  the  internal  super- 
ficies of  the  ventricles,  and  the  fissure  between 
the  two  hemispheres."  Theorbital  plexus  formed 
by  the  carotid  sends  off  the  inferior  palpebral, 
ethmoidal,  lachrymal,  and  ophthalmic  arteries. 
The  ophthalmic  artery  forms  two  remarkable 
plexuses  at  the  posterior  part  of  the  globe  of  the 

*  Dr.  Barkow  has  subsequently  established  the 
accuracy  of  this  observation,  having  found  this 
singular  anastomosis  of  the  occipital  with  the  ver- 
tebral artery  in  all  the  birds  which  he  has  injected. 
Tiedemann  is  therefore  inaccurate  in  saying  that  the 
vertebral  artery  has  the  same  termination  in  birds 
as  in  man. 


eye ;  the  first  is  situated  close  beside  the  inner 
side  of  the  optic  nerve,  and  is  formed  by  an 
artery  analogous  to  the  arteria  centralis  retime, 
and  gives  off  the  artery  to  the  base  of  the 
marsupial  membrane;  the  second  plexus  is 
situated  more  exteriorly,  and  gives  off  the  ciliary 
arteries. 

"After  the  trunk  of  the  carotid  has  sent  off  the 
internal  carotid,  it  passes  for  a  little  way  down- 
wards and  forwards  behind  the  angle  of  the  jaw, 
and  divides  at  once  into  different  branches,  cor- 
responding to  those  of  the  external  carotid  in 
mammalia ;  the  first  of  which  might  be  called 
the  oasophageal  or  laryngeal  artery.  This  vessel 
sends  a  branch  to  the  muscles  upon  the  horn 
of  the  os  hyoides,  and  then  turns  downwards 
and  divides  into  two  branches,  one  to  the 
trachea  (G,fig.  170),  and  the  other  to  the  oeso- 
phagus, upon  the  side  of  which  parts  they 
descend  to  near  the  thorax,"  forming  a  series  of 
arches  (11,  11),  and  ultimately  inosculate  with 
the  tracheal  and  oesophageal  branches  of  the 
common  trunk  of  the  carotid  and  vertebral 
arteries. 

"  The  external  maxillary  artery  (12)  dips  in 
between  the  pterygoid  muscle  and  that  which  is 
situated  at  the  back  of  the  lower  jaw  for  open- 
ing the  mouth ;  it  then  passes  behind  the 
tympanic  bone,  and  gives  twigs  upwards  to  the 
muscles  of  the  jaws,  and  to  the  plexus  at  the 
back  of  the  orbit :  upon  emerging  from  behind 
the  tympanic  bone,  it  lies  under  the  zygo- 
matic  or  jugal  bone,  and  sends  an  artery  up- 
wards, which  is  distributed  to  the  temporal 
and  masseter  muscles,  and  proceeding  under 
the  triangular  tendon  that  comes  from  the 
inferior  margin  of  the  orbit  to  the  lower  jaw, 
it  divides  into  two  principal  branches;  one  of 
these  passes  along  the  side  of  the  upper  jaw, 
gives  a  branch  upwards  to  the  fore  part  of  the 
orbit  which  unites  with  the  ophthalmic  artery, 
and  is  lost  at  the  top  of  the  head.  This  branch 
is  very  large  in  birds  with  combs,  as  in  con- 
junction with  the  ophthalmic,  it  furnishes 
numerous  vessels  to  these  vascular  parts.  The 
artery  then  goes  on  and  supplies  branches  to 
the  sides  of  the  head  before  the  orbits,  and  to 
the  integuments  and  substance  of  the  upper 
mandible,  inosculating  with  the  palatine  branches 
of  the  internal  maxillary  artery.  The  second 
portion  of  the  external  maxillary  proceeds  to 
the  lower  jaw,  to  which,  and  the  lower  part  of 
the  masseter  muscle,  it  is  distributed.  The 
external  maxillary  supplies  the  place  of  the 
temporal,  labial,  angular,  nasal,  and  mental 
arteries  of  mammalia. 

"  The  laryngeol  or  posterior  palatine  artery  is 
a  little  branch  of  the  external  carotid,  which 
is  sent  off  posteriorly  opposite  to  the  external 
maxillary  artery.  Its  branches  are  exhausted 
upon  the  back  part  of  the  fauces,  the  mus- 
cles for  moving  the  upper  jaw,  and  posterior 
nares. 

"  The  lingual  or  submaxillary  artery  (13) 
passes  under  the  muscles  which  connect  the  os 
hyoides  to  the  lower  jaw,  and  close  upon  the  back 
of  the  membrane  of  the  lower  part  of  the  mouth, 
it  sends  a  branch  to  the  resophagus  and  trachea, 
supplies  the  musc'es  of  the  os  hyoides  (F), 


334 


AVES. 


the  tongue  (E,  fig.  170\  the  lower  surface 
of  the  mouth,  and  furnishes  the  artery  which 
enters  the  substance  of  the  lower  jaw. 

"  Just  at  the  origin  of  the  submaxillary  artery 
there  is  another  little  branch  of  the  carotid, 
which  is  lost  upon  the  muscles  of  the  os 
hyoides. 

"  The  internal  maxillary  artery  is,  as  usual, 
the  continuation  of  the  trunk  of  the  external  ca- 
rotid ;  it  runs  forwards  between  the  pterygoid 
mflscle,  and  the  lining  of  the  mouth,  upon  the 
side  of  the  long  muscle  for  moving  the  upper 
jaw,  and  divides  into  two  principal  branches; 
one  of  them  proceeds  under  the  tendon  of  the 
long  muscle  to  get  upon  the  palate,  where  it 
forms  two  branches,  of  which  one  runs  along 
the  external  side  of  the  palate,  between  the 
membrane  and  the  bone  of  the  mandible  to 
the  extremity  of  the  bill,  where  it  becomes 
united  to  the  same  branch  of  the  opposite  side, 
as  also  to  the  middle  artery  of  the  palate.  The 
other  branch  lies  also  superficially  under  the 
membrane  which  lines  the  mouth.  It  passes 
onwards  to  meet  its  corresponding  vessel  of 
the  opposite  side,  with  which  it  becomes  ac- 
tually incorporated,  and  by  their  union  a  single 
artery  is  generated,  which  runs  along  the  mid- 
dle line  of  the  palate  to  the  end  of  the  mandi- 
ble, where  it  unites  with  the  lateral  branches, 
as  already  mentioned.  At  the  junction  of  the 
vessel  of  each  side  to  form  the  middle  pala- 
tine artery,  two  branches  go  off,  which  are  lost 
upon  the  lining  of  the  mouth,  and  the  interior 
of  the  organ  of  smell. 

"  The  other  branch  of  the  internal  maxillary 
artery  is  reflected  upwards  towards  the  orbit, 
below  which  it  divides  and  unites  again,  form- 
ing a  triangle,  through  which  the  vein  passes  : 
at  this  place  it  produces  a  remarkable  plexus 
of  vessels,  like  the  rete  mirabile  of  the  carotid 
artery  of  quadrupeds,  which  is  increased  by 
branches  from  the  ophthalmic  and  the  palatine 
arteries,  and  from  which  the  back  part  of  the 
organ  of  smell  receives  its  supply  of  blood. 

"  The  internal  maxillary  artery  then  runs  direct- 
ly backwards  below  the  orbit,  passes  between  the 
radiated  or  fan-shaped  muscle  which  moves 
the  upper  jaw  and  the  pterygoid  process ;  and 
turning  inwards  round  the  basis  of  the  cranium, 
becomes  incorporated  with  the  internal  carotid 
artery  just  as  it  enters  the  bony  canal  which 
conducts  it  to  the  brain.* 

"  The  vertebral  artery  (6),  soon  after  it  parts 
from  the  carotid,  sends  off  a  branch  backwards, 
which  passes  over  the  neck  of  the  scapula  and 
is  lost  among  the  muscles  on  the  posterior  part 
of  the  shoulder,  inosculating  with  the  articular 
and  other  arteries  about  the  joint :  this  branch 
might  be  called  the  supra-scapular  (5).  In  the 
duck  we  have  observed  it,  before  it  makes  the  turn 
over  the  scapula,  to  send  an  artery  upwards 
along  the  muscles  of  the  neck.  The  trunk  of 
the  vertebral  artery  proceeds  obliquely  upwards, 

*  Barkow  describes  the  internal  maxillary  artery 
as  wanting  in  birds,  and  its  place  being  supplied  by 
branches  of  both  the  external  and  internal  carotids 
and  the  facial  artery,  all  of  which  sometimes  unite 
to  form  the  maxillary  plexus  of  vessels,  which  is 
very  conspicuous  in  the  Goose  and  Duck. 


and  having  entered  the  foramen  in  the  transverse 
process  of  the  second  cervical  vertebra,  gives  off 
a  large  branch  downwards,  which  is  distributed 
between  the  vertebrae,  and  to  the  spinal  canal, 
in  the  manner  of  the  intercostal  arteries,  with 
which  it  anastomoses  upon  arriving  in  the 
thorax.  The  remainder  of  the  vertebral  artery 
is  continued  upwards  in  the  canal  formed  in 
the  transverse  processes  of  the  cervical  vertebrae, 
diminishing  gradually  in  consequence  of  the 
branches  it  sends  off  between  each  vertebra  to 
the  spinal  marrow  and  the  muscles  of  the  neck. 
Near  the  head  the  artery  is  found  considerably 
reduced,  and  within  the  last  foramen  in  the 
transverse  processes  terminates  entirely  by 
inosculation  with  the  reflected  occipital  branch 
of  the  carotid,  as  before  noticed. 

"  The  extraordinary  anastomoses  and  the 
plexuses  which  are  to  be  observed  in  the  arte- 
ries of  the  head  in  birds  are  not  easily  ac- 
counted for.  It  seems  possible  that  they  may 
be  required  in  consequence  of  the  great  length 
of  the  neck  in  these  animals,  it  being  well 
known  that  frequent  communication  amongst 
the  vessels,  although  it  diminishes  the  impetus 
of  the  circulation,  ensures  a  free  and  uninter- 
rupted motion  of  the  blood. 

"  After  the  common  trunk  of  the  carotid  and 
vertebral  is  detached  from  the  arteria  innominata, 
this  vessel  may  assume  the  name  of  the  sub- 
daman  (14).  While  passing  under  the  clavicle 
it  sends  off  some  important  branches :  the  first 
might  be  called  the  pectoral  artery;  it  proceeds 
upwards  upon  the  internal  surface  of  the  pec- 
toralis  minimus  muscle,  which  it  supplies,  and 
then  dividing  into  two  branches,  one  passes 
over  the  anterior  edge  of  the  clavicle,  and  under 
the  pectoralis  medius,  between  which  and  the 
sternum  it  runs,  detaching  its  branches  to  the 
muscle ;  the  other  sends  first  along  the  under 
side  of  the  clavicle  a  branch  which  is  again 
subdivided  and  distributed  to  the  outside  of 
the  shoulder-joint  and  to  the  deltoid  muscle, 
in  which  it  inosculates  with  the  articular  artery. 
The  vessel  then  passes  between  the  clavicle 
and  the  fork-shaped  bone,  and  on  a  ligament 
which  connects  the  head  of  the  clavicle  to  that 
of  the  scapula,  and  disperses  its  branches 
upon  the  upper  part  of  the  shoulder-joint,  form- 
ing anastomoses  with  the  neighbouring  arteries. 

"  The  next  branch  of  the  subclavian  is  the 
humeral  artery  (15);  it  arises  from  the  upper 
side  of  the  vessel,  and  makes  a  slight  curve 
to  reach  its  situation  on  the  inside  of  the  arm 
in  order  to  disperse  its  branches  in  the  manner 
hereafter  described. 

"  The  internal  mammary  artery  (24,/g.  171) 
is  given  off  just  as  the  subclavian  leaves  the 
chest.  It  divides  into  three  branches;  one 
ramifies  upon  the  inner  surface  of  the  sternum, 
another  upon  the  sternal  ribs  and  the  inter- 
costal muscles,  and  the  third  runs  along  the 
anterior  extremities  of  the  vertebral  ribs,  sup- 
plying the  intercostal  muscles,  &c. 

"  The  chief  peculiarity  of  the  arteries  of  the 
superior  extremities  in  birds  consists  in  the 
great  magnitude  of  the  vessels  which  supply 
the  pectoral  muscles ;  these,  instead  of  being 
inconsiderable  branches  of  the  axillary  artery, 


AVES. 


335 


are  the  continuations  of  the  trunk  of  the  sub- 
clavian,  of  which  the  humeral  is  only  a  branch. 
"  The  great  pectoral  or  thoracic  artery  passes 
out  of  the  chest  over  the  first  rib  and  close  to 
the  sternum,  and  immediately  divides  into  two 
branches.  One  of  them  (16)  ramifies  in  the 
superior  part  of  the  pectoralis  major,  and  the 
other  (17)  is  exhausted  in  the  lower  part  of  the 
muscle,  and  sends  off  a  branch  analogous  to 
the  long  thoracic  artery  of  mammalia."  Nos.  16 
and  17  show  the  distribution  of  these  arteries  to 
the  skin  after  perforating  the  pectoralis  muscle. 
"  The  humeral  artery,  while  within  the  axilla, 
gives  a  small  branch  backwards  to  the  muscles 
under  the  scapula,  and  upon  reaching  the 
inside  of  the  arm  produces  an  artery  that  soon 
divides  into  the  articular  and  the  profunda 
luimcri.  The  articular  artery  passes  round  the 
head  of  the  humerus,  underneath  the  extensors ; 
its  branches  penetrate  the  deltoid  muscle,  and 
anastomose  with  the  other  small  arteries  around 
the  joint. 

"  The  profunda  humeri,  as  usual,  turns  under 
the  extensor  muscles  to  reach  the  back  of  the 
bone,  at  which  place,  in  birds,  it  separates  into 
two  branches,  of  which  one  descends  upon  the 
inside,  and  the  other  upon  the  outside  of  the 
articulation  of  the  humerus  with  the  radius  and 
ulna,  and  there  inosculate  with  the  recurrent 
branches  of  the  arteries  of  the  fore-arm. 

"  After  the  humeral  artery  has  sent  off  the  pro- 
funda, it  descends  along  the  inner  edge  of  the 
biceps  muscle,  detaching  some  branches  to  the 
neighbouring  parts  :  upon  arriving  at  the  fold 
of  the  wing,  it  divides  into  two  branches ;  one 
of  these  is  analogous  to  the  ulnar  artery,  and 
the  other  from  its  position  deserves  to  be  called 
rather  the  interosseous  than  the  radial  artery. 

"  At  the  place  where  the  humeral  produces 
the  two  arteries  of  the  fore-arm,  a  small  branch  is 
sent  off,  which  is  lost  upon  the  fore-part  of  the 
joint,  and  in  anastomoses  with  the  recurrent  of 
the  ulna  and  profunda  humeri. 

"  The  ulnar  artery  is  the  principal  division  of 
the  humeral ;  it  proceeds  superficially  over  the 
muscles  which  are  analogous  to  the  pronator, 
sends  a  large  recurrent  branch  under  the  flexor 
ulnaris  to  the  back  of  the  joint,  upon  which  it 
ramifies  and  forms  anastomoses  with  the  pro- 
funda humeri.  The  artery  then  proceeds  along 
the  inner  edge  of  the  ulnar  muscles,  to  which 
it  distributes  branches.  It  is  afterwards  seen 
passing  over  the  carpal  bone  of  the  ulnar  side, 
and  under  the  annular  ligament,  at  which  place 
it  sends  off  some  branches  which  spread  upon 
the  joint  and  inosculate  with  the  similar  ones 
of  the  interosseous  artery.  Very  soon  after  the 
ulnar  artery  gets  upon  the  metacarpus,  it  dips 
in  between  the  bones,  and  re-appears  upon  the 
opposite  side,  lying  under  the  roots  of  the 
quills,  to  each  of  which  it  sends  an  artery  ;  it 
preserves  this  situation  to  the  end  of  the  m eta- 
carpal  bones,  where  it  passes  between  the  style 
analogous  to  the  little  finger  and  the  principal 
or  fore-finger,  and  pursues  its  course  along  the 
edge  of  the  latter,  to  the  extremity  of  the  wing, 
supplying  each  of  the  true  quills  with  an  artery, 
and  sending  at  each  joint  of  the  finger  a  cross 


branch  to  communicate  with  the  anastomosing 
branches  on  the  opposite  side. 

"  The  /M/fms.sro«.s  artery  detaches  first  a  brand  i 
of  some  size  to  the  membrane  which  is  spread  in 
the  fold  of  the  wing,  upon  which  it  forms  several 
ramifications.  (See  o,  jig.  171.)  After  this  the 
artery  dips  down  behind  the  pronator  muscles  to 
get  into  the  space  between  the  ulna  and  radius. 
It  here  gives  a  branch  backwards  to  communi- 
cate with  the  others  about  the  joint,  and  pro- 
ceeds in  the  interosseous  space  as  far  as  the 
carpal  joint,  during  which  course  they  become 
much  diminished  from  giving  oft  several 
branches  which  are  distributed  to  the  integu- 
ments and  the  quills  placed  upon  the  outside 
of  the  ulna.  The  remainder  of  the  interosseous 
artery  is  expended  in  small  branches  upon  the 
back  of  the  carpal  joint,  the  bastard  quills,  and 
along  the  radial  edge  of  the  metacarpus  and 
bones  of  the  fore-finger,  where  it  forms  com- 
munications with  the  cross  branches  of  the 
ulnar  artery  already  mentioned. 

"  From  this  description  it  will  be  perceived 
that  no  artery  exists  in  birds  strictly  analogous 
to  the  radial ;  that  there  are  no  palmar  arches ; 
and  that  the  size  of  the  interosseous  artery,  and 
the  course  of  the  ulnar,  along  the  outside  of  the 
metacarpus,  are  peculiarities  which  arise  from 
the  necessity  of  affording  a  large  supply  of 
blood  to  the  quills  during  their  growth. 

"The  descending  aorta  (19,  fg.  170)  makes 
a  curve  round  the  right  auricle  and  right 
bronchus,  in  order  to  get  upon  the  posterior 
surface  of  the  heart,  after  which  its  course 
is  close  along  the  spine,  in  which  situation  it 
is  bound  down  by  cellular  substance,  and  the 
strong  membrane  or  aponeurosis,  which  covers 
the  lungs  on  their  anterior  part.  The  first 
branches  which  this  vessel  appears  to  send  off 
are  bronchial  arteries ;  they  arise  from  the  fore 
part  of  the  aorta,  just  when  it  arrives  upon  the 
spine ;  and  having  entered  the  lungs,  their  ra- 
mifications accompany  those  of  the  pulmonary 
arteries.  They  appear  also  to  send  branches  to 
the  spine  and  the  spaces  between  the  ribs. 

"  The  intercostal  arteries  do  not  take  their 
origin  from  the  aorta  in  numerous  and  regular 
branches  as  in  mammalia,  but  consist  originally 
of  but  few  vessels,  which  are  multiplied  by 
anastomoses  with  each  other,  and  with  the 
arteries  which  come  out  of  the  spinal  canal. 
An  arterial  plexus  is  thus  formed  round  the 
heads  of  the  ribs,  from  which  a  vessel  is  sent 
to  each  of  the  intercostal  spaces.  Many  of 
these  branches,  besides  supplying  the  intercos- 
tal muscles  and  ribs,  are  continued  into  the 
muscles  upon  the  outside  of  the  body  and  the 
integuments.  The  anastomosis  of  the  inter- 
costal arteries  round  the  ribs  is  very  similar  to 
the  plexus,  which  is  produced  by  the  great 
sympathetic  nerve  in  the  same  situation. 

"  The  aorta  produces  no  branch  which  de- 
serves the  name  of  the  phrenic  artery,  as  birds 
do  not  possess  that  muscular  septum  of  the 
body  to  which  the  artery  of  this  name  is  dis- 
tributed in  other  animals. 

"The  caliac  artery  (20,  fig.  170)  is  a  very  large 
single  trunk,  and  arises  from  the  fore  part  of  the 


330 


AVES. 


aorta,  even  higher  than  the  zone  of  the  gastric 
glands.  It  descends  obliquely  for  a  short  way, 
and  then  gives  off  a  branch  which  soon  divides 
into  two  or  three  others  that  are  spread  upon 
the  lower  part  of  the  oesophagus,  and  the  side 
of  the  zone  of  the  gastric  glands,  uniting  with 
the  other  arteries  of  the  oesophagus  above,  and 
extending  downwards  upon  the  posterior  side 
of  the  ventricle,  and  anastomosing  with  the  an- 
terior gastric  artery.  The  trunk  of  the  cceliac 
now  divides  into  two  very  large  branches, 
which  from  their  distribution  we  have  chosen 
to  call  the  posterior  and  the  anterior  gastric 
arteries. 

"  The  posterior  gastric  artery,  almost  as  soon 
as  it  is  formed,  detaches  the  splenic  artery; 
and  very  soon  after  it  furnishes  from  the  poste- 
rior side  of  the  vessel  the  right  hepatic  artery. 
This  brand i  proceeds  to  the  right  lobe  of  the 
liver,  which  it  enters  on  the  side  of  the  hepatic 
duct;  after  having  divided  into  two  or  three 
minute  arteries  on  its  way  to  the  liver,  it  sup- 
plies the  hepatic  duct  with  a  branch  which 
accompanies  the  duct  to  the  intestine,  and  is 
there  lost.  The  posterior  gastric  artery  then 
runs  down  upon  the  back  of  the  gizzard,  and 
opposite  to  the  origin  of  the  first  intestine  it 
sends  off  an  artery,  which  proceeds  directly  to  one 
of  the  coeca(in  the  Fowl),  upon  which  and  the  side 
of  the  next  intestine  it  is  expended,  inosculating 
at  the  end  of  the  ccecum  with  branches  of  the 
mesenteric  artery,  which  are  distributed  to  the 
adjoining  portion  of  the  small  intestine.  The 
posterior  gastric  then  furnishes  a  large  vessel 
which  runs  upon  the  gizzard,  and  divides  into 
two  chief  branches,  which  penetrate  the  sub- 
stance of  the  digastric  muscle,  in  which  they 
are  lost. 

"  The  next  branch  of  the  posterior  gastric 
artery  is  the  pancreatic.  It  runs  between  the 
two  pancreatic  glands,  dispensing  branches  to 
each  and  to  the  duodenum.  After  this  the 
trunk  of  the  posterior  gastric  divides  into  two 
branches,  which  furnish  twigs  to  the  muscular 
parietes  of  the  ventricle,  and  run  along  the 
margins  of  the  upper  and  lower  portions  of  the 
digastric  muscle.  Supplying  them  with  nume- 
rous twigs,  and  anastomosing  with  the  ramifi- 
cations of  the  other  gastric  arteries. 

"  The  anterior  gastric  artery  descends  to  the 
angle  formed  by  the  bulbus  glandulosus  and 
the  gizzard,  and  there  sends  off  a  small  branch 
which  spreads  upon  the  zone  of  the  gastric 
glands,  and  inosculates  with  the  first  ramifica- 
tions of  the  cceliac,  and  immediately  afterwards 
it  detaches  a  large  artery,  which  runs  round  the 
superior  margin  of  the  digastric  muscle,  which 
it  furnishes  with  many  twigs,  and  communi- 
cates freely  with  the  corresponding  branch  of 
the  posterior  gastric  artery. 

"  Three  small  hepatic  arteries  take  their 
origin  from  this  branch  of  the  anterior  gastric, 
just  as  it  passes  over  the  highest  part  of  the 
margin  of  the  gizzard ;  these  vessels  enter  the 
fissure  in  the  left  lobe  of  the  liver.  The  ante- 
rior gastric  artery  now  proceeds  along  the  fore 
part  of  the  gizzard,  sending  one  or  two  brandies 
into  the  muscular  substance,  and  near  the  ten- 


don it  terminates  in  two  large  vessels,  one  of 
which  is  distributed  upon  the  left  side  of  the 
digastric  muscle,  and  the  other  passes  a  little 
over  the  tendon,  and  then  divides  into  two 
arteries,  which  produce  several  branches  that 
disappear  in  the  substance  of  the  gizzard,  and 
between  the  digastric  muscles  and  the  parietes 
of  the  ventricle,  anastomosing  with  the  vessels 
of  the  posterior  side. 

"  The  superior  mesenteric  artery  (2 1  tfg.  1 70) 
takes  its  origin  from  the  fore  part  of  the  aorta,  a 
little  below  the  cceliac,  and  proceeds  for  some 
way  without  detaching  any  branches;  after 
which  it  experiences  the  same  kind  of  division 
and  subdivision  that  takes  place  in  mammalia ; 
and  the  numerous  arteries  which  are  thus  ulti- 
mately produced  are  spent  upon  the  small  intes- 
tines. One  of  the  first  and  largest  branches  of 
the  superior  mesenteric,  however,  is  allotted  to 
supply  one  of  the  cceca,  and  to  establish  a  com- 
munication with  the  inferior  mesenteric  and 
gastric  arteries.  This  branch,  soon  after  it 
leaves  the  trunk  of  the  superior  mesenteric, 
divides  into  two.  One  descends  upon  the  rec- 
tum, where  it  meets  with  the  inferior  mesenteric 
artery,  with  which  it  produces  a  very  remark- 
able anastomosis,  similar  to  the  mesenteric  arch 
in  the  human  subject ;  this  united  artery  sup- 
plies the  rectum  and  origin  of  the  co2ca.  The 
second  portion  of  this  branch  of  the  superior 
mesenteric  runs  in  the  space  between  the  last 
part  of  the  small  intestine  and  the  ccacum  of 
one  side,  sending  numerous  branches  to  each, 
and  at  the  end  of  the  ccecum  communicates  in 
a  palpable  manner  with  another  branch  of  the 
superior  mesenteric  artery,  which  runs  upon  the 
adjoining  part  of  the  small  intestine. 

"A  branch  (22,  Arteria  spermatica)  arises 
from  the  anterior  part  of  the  aorta,  just  below 
the  lungs;  it  is  designed  for  the  nutrition  of 
the  organs  of  generation,  and  except  in  the 
season  for  propagation,  it  is  so  small  as  to 
be  discovered  with  difficulty  ;  but  when  the 
testicles  become  enlarged,  it  is  considerably 
increased  in  size  in  the  male  bird,  and  much 
more  so  in  the  female,  when  the  ovary  and 
oviduct  are  developed  for  producing  eggs.  It 
nearly  equals  the  superior  mesenteric  artery 
during  the  period  of  laying,  in  which  state  we 
shall  describe  it.  It  is  a  single  artery,  like  the 
cceliac  and  mesenteric,  proceeds  at  a  right  angle 
from  the  aorta,  and  soon  sends  off  a  branch, 
which  goes  into  the  kidney  of  the  left  side,  to 
which  it  gives  some  twigs,  and  afterwards 
emerging  from  the  kidney,  it  runs  in  the  mem- 
brane of  the  oviduct,  upon  which  it  is  distri- 
buted. After  this  branch  is  detached,  the 
artery  projects  a  little  farther  forwards  into 
the  cavity,  and  divides  into  two  branches;  one 
of  these  goes  to  the  ovary,  in  which  it  ramifies, 
and  furnishes  an  artery  of  some  size  to  each  of 
the  cysts  containing  the  ova.  The  other  is  dis- 
tributed in  numerous  branches  to  the  mem- 
brane and  superior  parts  of  the  oviduct,  and 
inosculates  with  the  other  arteries  of  the 
oviduct.  It  deserves  to  be  remarked,  that  this 
and  all  the  other  arteries  which  are  furnished 
to  the  oviduct  have  a  tortuous  or  undulating 


AVES. 


337 


course,  in  the  same  manner  as  the  vessels  of 
the  uterus  of  the  human  subject. 

"  There  are  no  regular  cmu/gcnt  arteries  in 
birds;  the  kidneys  deriving  their  blood  from 
various  sources,  which  will  be  pointed  out  as 
they  occur. 

"  The  inferior  extremity  is  supplied  with  two 
arteries,  which  have  a  separate  origin  from  the 
aorta.  One  corresponds  with  the  femoral  ar- 
tery, and  the  other  deserves  the  name  of  ischia- 
dic  artery. 

"The  femoral  artery  (23,  fg.  170,  171)  is  a 
small  trunk,  which  takes  its  origin  from  the  side 
of  the  aorta,  opposite  to  the  notch  in  the  bones  of 
the  pelvis  immediately  under  the  last  rib.  This 
notch  is  formed  into  a  round  hole  in  the  recent 
subject  by  a  ligament  which  is  extended  from  it 
to  the  rib ;  and  it  is  through  this  hole  that  the 
femoral  artery  makes  itsexitfrom  the  pelvis;  just 
before  it  passes  out  upon  the  thigh,  it  sends  off  a 
long  branch  (25),  which  runs  backwards  the 
whole  length  of  the  margin  of  the  pelvis,  dis- 
pensing arteries  to  the  abdominal  muscles  on  one 
side,  and  the  obturator  internus  on  the  other. 
This  branch  also  appears  to  supply  one  to  the 
oviduct.  The  femoral  artery,  immediately  after 
leaving  the  pelvis,  separates  into  two  branches; 
one  goes  upwards  and  outwards,  ramifying 
amongst  the  muscles  in  that  situation ;  the 
other  turns  downwards,  and  is  distributed  to 
the  flexors  of  the  limb  and  round  the  joint,  and 
sends  an  artery  to  the  edge  of  the  vastus  inter- 
nus, which  can  be  traced  as  far  as  the  knee. 
The  kidneys  appear  to  derive  some  irregular 
inconsiderable  branches  from  the  femoral  artery 
while  it  is  within  the  pelvis. 

"The  ischiadic  artery  (26,  fg.  166,  170) 
is  the  principal  trunk  of  the  lower  extremities, 
exceeding  very  much  in  size  the  femoral.  When 
it  is  produced  by  the  aorta,  it  appears  to  be  the 
continuation  of  that  trunk  ;  the  remaining  part 
of  the  aorta  becomes  so  much  and  so  suddenly 
diminished,  and  seems,  as  it  were,  to  proceed  as 
a  branch  from  the  back  part  of  the  vessel. 

"  The  ischiadic  artery,  while  in  the  pelvis,  is 
concealed  by  the  kidneys,  in  which  situation  it 
gives  a  branch  from  its  lower  side,  which  di- 
vides into  three  others  that  are  distributed  to 
the  substance  of  the  kidneys  ;  one  of  these  on 
the  left  side  is  continued  out  of  the  kidney  to 
be  lost  upon  the  oviduct.  The  artery  leaves 
the  pelvis  by  the  ischiadic  foramen  in  company 
with  the  great  nerve,  while,  within  the  foramen, 
it  gives  a  branch  obliquely  downwards  under 
the  biceps  to  the  muscles  lying  in  the  pelvis ; 
and  as  it  passes  over  the  adductor  it  sends  off 
another  along  the  lower  edge  of  that  muscle, 
which  is  chiefly  lost  in  the  semi-membranosus. 
It  then  detaches  several  small  branches  to  the 
muscles  on  the  outer  and  fore  part  of  the 
thigh,  some  of  which  anastomose  round  the 
joint  with  the  branches  of  the  femoral  artery. 
Just  as  the  ischiadic  arrives  in  the  ham,  it 
furnishes  a  very  large  branch  downwards, 
which  divides  into  two ;  one  goes  under  the 
gastrocnemius,  to  which  and  the  deep-seated 
flexors  its  branches  are  distributed  as  far  as  the 
heel ;  the  other  is  analogous  to  the  peroneal 
artery ;  it  goes  to  the  outside  of  the  leg,  sup- 

VOL.   I. 


phes  the  peroneal  muscles  posteriorly,  and 
passes  along  the  outer  edge  of  the  flexors  of 
the  toes  to  the  heel,  above  which,  and  behind 
the  flexor  tendon,  it  divides,  running  on  each 
side  of  the  heel,  and  forming  several  articular 
arteries  around  the  joint,  and  communicating 
with  the  other  branch,  and  with  the  anterior 
tibial,  and  the  metatarsal  branch  of  the  plantar 
artery. 

"  The  articular  arteries  go  off  next  from  the 
artery  in  the  ham  ;  the  two  principal  ones  are 
deep-seated.  One  proceeds  under  the  vastus 
internus  to  the  external  part  of  the  joint;  the 
other  is  large,  and  situated  upon  the  inside. 
It  forms  two  vessels  :  one  is  the  true  articular 
artery,  and  spreads  upon  the  ligaments  of  the 
joint;  the  other  is  distributed  in  the  substance 
of  the  flexor  of  the  heel,  which  is  placed  upon 
the  inside  and  fore  part  of  the  leg,  and  comes 
out  upon  the  edge  of  this  muscle  to  be  lost  in 
the  integuments. 

"  The  posterior  tibial  artery  (28,  fig.  171) 
is  extremely  small;  it  only  supplies  muscular 
branches  to  the  internal  head  of  the  gastrocne- 
mius, and  some  of  the  flexors  of  the  toes  ;  it 
is  lost  on  the  inside  of  the  heel  in  anastomoses 
with  the  peroneal  artery,  and  other  small 
superficial  branches. 

"  The  trunk  of  the  artery  of  the  leg  now  gels 
upon  the  posterior  surface  of  the  tibia,  and 
sends  off,  through  the  deficiency  left  between 
the  tibia  and  fibula  at  the  superior  part,  a 
branch  which  is  distributed  to  all  the  muscles 
upon  the  fore  part  of  the  leg.  The  artery  then 
creeps  along  the  back  of  the  bones  for  some 
way,  and  passing  between  them  above,  where 
the  fibula  is  anchylosed  with  the  tibia,  it  re- 
appears on  the  anterior  part  of  the  leg  in  the 
situation  of  the  anterior  tibial  artery;  at  this 
place  it  detaches  some  very  small  "branches, 
which  frequently  diride  and  unite  again,  to 
produce  a  most  singular  reticulation  or  plexus 
of  vessels,  which  closely  adheres  to  the  trunk 
of  the  artery,  and  is  continued  with  it  as  far  as 
the  articulation  of  the  tibia  with  the  metatarsal 
bone,  where  it  disappears  without  seeming  to 
answer  any  useful  design.  This  plexus  resem- 
bles in  appearance  exactly  the  division  of  the 
arteries  of  the  extremities,  which  has  been 
described  by  Mr.  Carlisle  in  the  tardigrade 
quadrupeds,  but  differs  from  it  in  this  cir- 
cumstance, that  the  trunk  of  the  artery  is  pre- 
served behind  it,  without  suffering  any  "material 
diminution  of  its  size. 

"  The  anterior  tibial  artery  furnishes  no 
branch  of  any  importance  during  the  time  it  is 
proceeding  along  ihe  fore  part  of  the  leg.  It 
passes  under  the  strong  ligament  which  binds 
down  the  tendons  of  the  anterior  muscles  of 
the  leg,  and  over  the  fore  part  of  the  joint  on 
the  inside  of  the  tendon  of  the  tibialis  anticus, 
at  which  places  it  distributes  some  branches 
which  inosculate  with  the  other  arteries  round 
the  joint ;  it  then  pursues  its  course  in  the 
groove  along  the  anterior  surface  of  the  meta- 
tarsal bone,  and  covered  by  the  tendon  of  the 
flexor  digitorum.  On  coming  near  the  foot  it 
sends  off  an  artery,  which  divides,  behind  the 
joint  of  the  internal  toe,  into  two  branches ; 


338 


AVES. 


one  goes  between  the  internal  and  middle  toes, 
ramifies  upon  both  their  joints,  and  unites  with 
the  artery  in  the  sole  of  the  foot ;  the  other  is 
distributed  between  the  internal  toe,  and  the 
pollex  or  toe  which  occupies  the  place  of  the 
great  toe ;  the  main  artery  now  passes  to  the 
sole  of  the  foot  through  a  hole  in  the  meta- 
tarsal  bone,  left  for  the  purpose,  when  the 
original  parts  of  this  bone  were  united  by  ossi- 
fication. In  this  situation  the  artery  might 
receive  the  name  of  the  plantar.  It  has 
scarcely  passed  through  the  bone,  when  it  di- 
vides into  six  branches;  three  of  these  are 
distributed  to  the  tendons  and  ligaments,  &c. 
on  the  outside  of  the  foot  and  the  back  of  the 
metatarsus,  anastomosing  with  the  descending 
branches  of  the  peroneal  artery;  the  fourth 
branch  supplies  the  pollex,  and  also  sends  a 
branch  from  the  metatarsus.  The  remaining 
branches  are  designed  for  the  three  principal 
toes;  one  dips  in  between  the  internal  and 
middle  toe,  unites  with  the  anterior  branch  of 
the  metatarsal  artery,  and  is  distributed  to  the 
sides  of  these  toes  as  far  as  their  extremity. 
The  other  divides,  between  the  external  and 
middle  toe,  into  two  branches,  which  run  upon 
the  opposite  side  of  each  of  these  toes  to  the 
end. 

"  When  the  feet  are  webbed,  the  digital  ar- 
teries send  off  numerous  branches,  which,  ra- 
mifying in  the  membrane  between  the  toes, 
establish  a  communication  with  each  other. 
The  present  description  has  been  taken  from 
birds  which  possess  three  principal  toes,  and 
the  back  toe  or  pollex  ;  but  no  material  diffe- 
rence can  be  expected  in  those  with  a  greater 
number  of  toes. 

"  After  the  trunk  of  the  aorta  has  detached 
the  ischiadic  arteries,  it  is  continued  along  the 
spine  as  the  arteria  sacra  media  (29,  jig.  170), 
sending  off  small  branches  analogous  to  the 
lumbar  arteries,  one  of  which  ascends  upon 
the  rectum,  supplies  the  place  of  the  inferior 
mesenteric  (30,  jig.  170),  and  unites  with  the 
superior  mesenteric  as  already  mentioned.  The 
aorta  separates  above  the  coccygeal  vertebrae 
into  three  branches ;  two  of  these,  (the  hypo- 
gastric  arteries,  3\,jig.  170,)  proceed  laterally, 
and  are  distributed  to  the  neighbouring  parts, 
and  to  the  kidneys  and  oviduct;  the  third 
branch  (the  coccygeal  artery,  32,  jig.  170)  de- 
scends to  the  very  point  of  the  tail,  upon  the 
muscles  and  quills  of  which  its  branches  are 
exhausted. 

"  The  arterial  system  of  birds,  besides  the 
distinguishing  characters  above-mentioned,  dif- 
fers from  that  of  mammals  chiefly  in  the  fre- 
quent anastomoses,  which  exist  more  especially 
amongst  the  arteries  of  the  head  and  the 
viscera.  Similar  communications  occur  between 
the  veins,  which  are  even  in  some  instances 
more  singular  and  unaccountable,  as  will  be 
perceived  by  the  following  description,  which 
has  been  taken  principally  from  the  Goose, 
Duck,  and  Common  Fowl." 

Besides  the  remarkable  arterial  plexuses  men- 
tioned in  the  general  description,  as  the  orbital, 
the  temporal,  the  spermatic  plexuses,  &c.,  that 
which  Barkow  has  described  under  the  name  of 


the  plexus  of  the  organ  of  incubation  (Brvt- 
organe)  deservese  special  notice.  It  is  repre- 
sented at  17,  18,  Jig.  170,  and  is  composed 
of  branches  coming  from  the  posterior  thoracic, 
abdominal,  cutaneous,  and  ischiadic  arteries, 
which  ramify  beneath  the  integument  of  the 
abdomen,  and  form,  by  their  unions,  a  rich  net- 
work of  vessels  which  becomes  truly  extraordi- 
nary in  the  time  of  hatching.  At  this  period 
many  birds  pluck  off  the  feathers  from  the  seat 
of  incubation,  probably  thereto  impelled  by  the 
great  degree  of  heat  caused  by  the  influx  of 
blood  into  the  incubating  plexus. 

Fig.  171. 


Veins  of  a  Fowl. 

"  Veins. — The  venous  system  returns  the 
blood  to  the  heart  by  means  of  three  trunks;  two 
of  these,  for  the  convenience  of  description,  we 
shall  call  the  subclavian  veins  (a  a,  jig.  166), 
although  they  do  not  correspond  in  every  respect 
with  the  veins  of  this  name  in  mammalia ;  the 
other  trunk  is  analogous  to  the  inferior  vena  cava. 

"  The  subclavian  vein  (a,  jig.  171)  is  com- 
posed of  the  jugular  and  vertebral,  and  the 
veins  which  belong  to  the  superior  extremity  or 
wing. 

"  The  vertebral  vein  is  lodged  in  the  same 
canal  with  the  vertebral  artery;  it  anastomoses 
between  the  vertebrae  with  the  veins  upon  the 


AVES. 


339 


sheath  of  the  medulla  spinalis,  which  are  the 
continuation  of  the  sinuses  of  the  brain ;  in 
conjunction  with  these,  therefore,  the  vertebral 
vein  may  be  considered  as  answering  the  pur- 
pose of  the  internal  jugular  of  mammalia.  It 
appears  also  to  form  at  the  basis  of  the  cranium 
a  free  communication  with  the  jugular  vein, 
and  to  receive,  by  occasional  branches,  blood 
from  the  muscles  of  the  neck. 

"  The  jugular  vein  (6)  is  a  single  trunk  in 
birds,  and  does  not  admit  of  the  distinction 
into  external  and  internal ;  it  proceeds  super- 
ficially along  the  side  of  the  neck  in  company 
with  the  par  vagum  nerve.  The  vein  of  the 
right  side  exceeds  the  other  in  size ;  it  is  often 
twice  as  large.  The  jugular  vein  receives  several 
iateral  branches  from  the  muscles  and  integu- 
ments of  the  neck  (rf),  the  oesophagus,  &c.  (the 
veins  from  the  crop  joining  the  jugular  are 
shewn  at  c):  one  of  these  near  the  head  is 
much  longer  than  the  rest  (e);  it  lies  deep 
amongst  the  muscles,  and  appears  to  com- 
municate with  the  vertebral  vein.  There  is  a 
branch  of  the  jugular  which  goes  to  the  supe- 
rior larynx  amongst  the  muscles  of  the  tongue 
and  of  the  os  hyoides,  and  another  for  the 
muscles  within  the  jaws  and  the  integuments 
in  the  back  of  the  mouth ;  these  might  be 
called  the  lingual,  thyroid,  and  submaxillary 
veins  (g  h  i). 

"  The  jugular  veins  form  a  most  remarkable 
communication  with  each  other  immediately 
below  the  cranium,  by  means  of  a  cross 
branch,  generally  of  an  equal  size  with  the 
trunks  themselves.  From  each  side  of  the 
arch  thus  formed  there  issues  a  large  vessel, 
•which  is  made  up  of  the  veins  of  the  external 
part  of  the  head ;  one  of  these  passes  round 
the  articular  bone,  and  apparently  penetrates 
the  joint  of  that  bone  with  the  lower  jaw ;  it 
appears  in  several  branches  upon  the  side  of 
the  cheek,  and  spreading  from  the  ear  in  the 
manner  of  the  portio  dura  nerve  of  the  human 
subject,  and  contributes  to  form  a  plexus  of 
veins  below  the  posterior  part  of  the  orbit  (&), 
similar  to  the  arterial  plexus  already  described  in 
thatsituation.  The  principal  branch  oT the  veins  of 
the  head  passes  obliquely  round  the  interarticular 
(or  pterygoid)  bone,  and  below  the  orbit  divides 
into  several  large  vessels,  one  of  which  belongs 
to  the  back  part  of  the  palate  ;  another  ascends 
on  the  orbit,  and  unites  with  the  ophthalmic 
vein  ;  and  a  third  is  distributed  to  the  interior 
of  the  organ  of  smell,  the  palate,  and  the 
external  parts  of  the  upper  and  lower  jaws. 
These  branches  produce  plexuses  along  the 
base  of  the  orbit  and  the  external  edge  of  the 
palate,  which  correspond  to  those  of  the  arte- 
ries before  described. 

"  In  all  the  subjects  we  dissectedfor  the  veins, 
we  failed  to  discover  any  direct  communication 
between  the  jugular  vein  and  the  sinuses  of 
the  brain ;  and  in  every  instance  the  external 
veins  of  the  head  appeared  to  be  sufficiently 
large  of  themselves  to  produce  the  trunk  of 
the  jugular.  It  may,  therefore,  be  presumed 
that  if  any  branch  analogous  to  the  internal 
jugular  vein  passes  through  the  posterior  fora- 
men lacerum,  it  is  very  inconsiderable,  and 


incapable  of  transmitting  the  blood  of  th* 
brain. 

"  The  sinuses  of  the  brain  seem  to  discharge 
their  contents  principally  into  some  veins 
which  lie  in  the  membrane  forming  the  sheath 
of  the  spinal  canal,  and  these  appear  to  dispose 
of  their  blood  gradually,  as  they  descend  in 
the  neck  by  means  of  lateral  communication 
with  the  vertebral  veins.  The  sinuses,  which 
immediately  open  into  the  spinal  veins,  are 
situated  upon  the  back  of  the  cerebellum,  and 
produce,  by  anastomoses  with  each  other,  with 
the  superior  longitudinal  sinus,  and  with  others 
along  the  side  of  the  brain,  an  union  of  vessels 
of  a  diamond  shape. 

"  The  sinuses  of  the  brain  in  birds  generally 
are  irregular  in  their  form,  and  consist  of  flat- 
tened canals;  and  not  only  the  sinuses  on  the 
back  of  the  cerebellum,  but  the  spinal  veins 
appear  so  like  extravasation,  that  accurate  and 
repeated  observations  are  necessary  to  discover 
them  to  be  real  vessels. 

"  The  principal  sinuses,  besides  those  upon 
the  cerebellum,  are  the  superior  longitudinal, 
and  one  which  runs  along  the  lower  edge  of  each 
hemisphere  of  the  cerebrum  ;  there  appears  to 
be  also  one  upon  the  side  of  the  cerebellum, 
corresponding  to  the  lateral  sinus.  All  these 
sinuses  communicate  with  each  other  on  the 
back  of  the  cerebellum  as  already  mentioned. 
The  superior  longitudinal  sinus  is  continued  at 
its  anterior  part  under  the  frontal  and  nasal 
bones,  and  anastomoses  with  the  ophthalmic 
and  nasal  veins.  There  are  other  sinuses  in 
the  several  duplicatures  of  the  dura  mater, 
which  are  too  small  to  be  easily  traced  or  to 
deserve  much  regard. 

"  The  veins  of'  the  wings,  or  superior  ex- 
tremity, have  a  less  curious  distribution  than 
those  of  the  head.  The  branches  which  are 
derived  from  the  parts  within  the  chest,  the 
muscles  about  the  scapula,  and  the  pectoral 
muscles,  accompany  the  arteries  of  the  same 
parts  so  regularly  that  their  course  does  not 
require  description. 

"  The  axillary  vein  (/)  lies  considerably 
lower  in  the  axilla  than  the  artery,  but  still 
continues  to  receive  corresponding  branches; 
(m  indicates  the  great  pectoral  vein).  The 
trunk  of  the  vein  descends  in  the  course  of  the 
humeral  artery,  but  more  superficially ;  in  this 
situation  it  may  be  called  basilic,  or  more  pro- 
perly the  humeral,  vein  (n).  There  is  no  vein 
in  birds  which  deserves  the  name  of  the  ce- 
phalic ;  there  are  branches  of  the  humeral  vein, 
accompanying  the  articular  and  profunda  arte- 
ries, and  at  the  middle  of  the  humerus  a  large 
branch  of  the  vein  enters  the  bone ;  there  are 
also  two  very  small  branches  which  lie  in  close 
contact  with  the  humeral  artery,  which  they 
accompany  nearly  its  whole  length. 

"  The  principal  vein  of  the  wing  divides  into 
two,  opposite  to  the  joint  of  the  humerus  with 
the  fore-arm.  One  of  these  branches  (o)  belongs 
to  the  sides  of  the  radius ;  it  receives  blood 
from  the  muscles  and  skin  on  the  upper  part 
of  the  fore-arm,  but  its  chief  vessels  lie  be- 
tween the  integuments  of  the  fold  of  the  wing. 
The  other  branch  of  the  humeral  vein  (/>)  crosses 

z  2 


840 


AVES. 


the  fore-arm,  just  below  the  articulation  in 
company  with  the  nerve,  and  running  along 
the  inferior  edge  of  the  ulna,  receives  a  branch 
from  between  the  basis  of  each  quill,  is  con- 
tinued along  the  ligament  which  sustains  the 
rest  of  the  quills  to  the  extremity  of  the  wing, 
receiving  many  veins  of  the  joints  from  the 
opposite  side  of  the  ringers.  Besides  these 
large  superficial  veins  of  the  fore-arm,  there 
appears  to  be  one,  and  sometimes  two,  small 
accompanying  veins  to  the  ulnar  and  interos- 
seous  arteries  (y). 

"  The  inferior  vena  cava  (K),  before  it  enters 
the  auricle  (A),  receives  as  usual  the  hepatic 
veins  (s) ;  these  are  numerous,  and  open  into 
the  cava  as  it  passes  behind  the  liver,  or  more 
frequently  within  the  substance  of  that  viscus 
in  the  back  part.  We  have  reckoned  in  the 
Cock  two  large  and  two  small  hepatic  veins 
from  the  right  lobe,  and  one  large  branch  from 
the  left  lobe,  besides  six  minute  veins,  which 
came  indifferently  from  both  lobes. 

"  The  trunk  of  the  vena  cava  is  very  short 
in  the  abdomen;  it  separates  into  two  great 
branches  analogous  to  the  primary  iliac  veins  (£), 
opposite  to  the  renal  capsules ;  these  turn  to 
each  side,  and  experience  a  very  singular  dis- 
tribution. On  coming  near  the  edge  of  the 
pelvis  each  of  these  two  veins  forms  two 
branches ;  one  of  which  collects  the  blood  of 
the  lower  extremity,  as  hereafter  described;  the 
other  passes  straight  downwards  imbedded  in 
the  substance  of  the  kidney,  and  admits  the 
several  emulgent  veins,  which  are  very  large, 
and  are  seen  to  pass  for  some  way  obliquely 
in  the  kidney  before  their  termination.  Some- 
times the  emulgent  veins  are  double,  as  in  the 
figure,  (M).  The  descending  branch  of  the  iliac 
also  receives  the  ovarian  veins,  and  when  arrived 
at  the  lower  end  of  the  kidney,  divides  into  three 
branches;  one  transmits  the  blood  of  the  muscles 
of  the  tail  and  parts  adjacent ;  another  accom- 
panies the  ureter  to  the  side  of  the  rectum,  and 
is  distributed  about  the  anus  and  parts  of  gene- 
ration, answering  to  the  htemorrhoidul  veins ; 
the  third  (v,  v)  passes  inwards  to  the  middle  line 
between  the  kidneys,  and  there  unites  with  the 
corresponding  branch  of  the  opposite  side.* 
The  vessel  which  is  in  this  manner  produced 
(*)  receives  all  the  blood  of  the  rectum  from  the 
anus  to  the  origin  of  the  cceca,  anastomosing 
below  with  the  branches  of  the  hsemorrhoidal 
veins ;  and  at  the  upper  part  of  the  rectum, 
it  becomes  continuous  with  the  trunk  of  the 
veins  of  the  small  intestines  (.reforming  the  most 
remarkable  anastomosis  in  the  body,  both  on 
account  of  its  consequences  and  the  size  of  the 
vessels  by  which  it  is  effected.  By  means  of* 
this  communication,  the  blood  of  the  viscera 
and  the  external  parts  of  the  body  flows  al- 
most indifferently  into  the  vena  cava  and  vena 
portae  (iv) ;  for  the  anastomosing  vessels  are  suf- 
ficiently large  to  admit  the  ready  passage  of  a 
considerable  column  of  blood  in  proportion  to 
the  whole  mass  which  circulates  in  the  body 

*  It  is  these  branches  which  Professor  Jacobson 
supposes  to  carry  venous  blood  into  the  kidneys, 
for  the  purpose  of  supplying  material  for  the  uri- 
nary secretion. 


of  the  bird ;  for  instance,  in  the  Goose  the  com- 
municating veins  of  the  pelvis  are  equal  in 
size  to  a  goose-quill,  and  in  the  Ostrich  and 
Cassowary  they  are  as  thick  as  a  finger.  The 
advantage  which  appears  to  result  from  this 
remarkable  union  of  vessels,  is  the  prevention 
of  congestion,  or  the  overloading  either  the 
heart  or  liver  with  blood,  as  the  one  organ  has 
the  power  of  relieving  the  other.  It  would 
seem  from  this,  as  well  as  several  other  pro- 
visions of  the  same  kind,  that  the  circulation 
would  be  more  liable  to  obstruction  in  birds 
than  other  animals.*  It  is  difficult  to  say,  how- 
ever, to  what  cause  such  an  effect  ought  to  be 
ascribed.  Is  it  from  the  compression  sus- 
tained by  the  heart  and  other  viscera,  by 
means  of  the  air-cells  during  respiration  ?  or, 
is  the  mode  of  progression  by  flight  capable  of 
impeding  the  motion  of  the  blood  ? 

"  The  anastomosis  of  the  pelvic  veins,  in 
being  the  means  of  conveying  common  venous 
blood  into  the  liver,  goes  to  prove  that  the 
blood  of  the  vena  portae  does  not  require  any 
peculiar  preparation  by  circulation  in  the  spleen 
or  other  viscera,  which  has  been  conceived  as 
necessary  by  some  physiologists  to  fit  it  for  the 
secretion  of  bile. 

"  The  vena  portce  (w)  belongs  almost  exclu- 
sively to  the  right  or  principal  lobe  of  the  liver. 
It  is  formed  by  three  branches.  The  splenic  vein 
is  the  smallest,  and  is  added  to  the  vena  portae, 
just  as  it  penetrates  the  liver  on  the  side  of  the 
hepatic  duct.  The  next  is  made  of  two 
branches;  of  which  one  returns  the  blood  of 
the  posterior  gastric  artery,  and  therefore  may 
be  called  the  posterior  gastric  vein ;  and  the 
other  is  furnished  by  the  pancreas  and  duode- 
num, and  therefore  is  the  pancreatic  vein. 
The  third  and  largest  branch  of  the  vena 
portse  is  the  mesenteric  vein  (x\  which  not  only 
collects  the  blood  from  all  the  small  intestines, 
but  likewise  receives  the  inferior  mesenteric  (2), 
or  vein  of  the  rectum,  which  forms  the  com- 
munication that  has  been  described  with  the 
pelvic  veins. 

"  The  veins  of  the  left  lobe  of  the  liver  are 
furnished  in  the  goose  by  those  which  accom- 
pany the  anterior  gastric  artery,  and  some 
branches  from  the  head  of  the  duodenum. 

"  The  anterior  gastric  veins  produce  two  small 
trunks,  which  enter  at  the  two  extremities  of 
the  fissure,  in  the  concave  surface  of  the  left 
lobe  of  the  liver,  as  it  lies  upon  the  edge  of 
the  gizzard;  the  veins  from  the  head  of  the 
duodenum  furnish  a  small  vessel  which  passes 
backwards  to  penetrate  the  posterior  part  of 
the  fissure  in  the  left  lobe. 

"  In  the  c ock  the  veins  that  the  left  lobe  of  the 
liver  derives  from  the  anterior  gastric,  are  more 
numerous  than  in  the  goose, 

"  The  veins  of  the  zone  of  gastric  glands,  and 
of  the  lower  portion  of  the  oesophagus,  do  not 

*  Besides  their  anastomoses  the  principal  vis- 
ceral veins  are  remarkable  for  their  large  size  in 
the  Diving  Birds.  Cuvier  (Lemons  d'Anat.  Comp. 
iv.  p.  274 )  has  especially  noticed  the  dilatation  of 
the  inferior  cava  of  the  Grebes  (Colymbus),  which 
reservoir  he  compares  with  that  formed  by  the 
hepatic  veins  in  the  Seal. 


AVES. 


341 


contribute  to  the  secretory  vessels  of  the  liver, 
but  proceed  to  the  superior  part  of  that  viscus, 
to  terminate  in  the  vena  cava,  as  does  also  the 
umbilical  vein. 

"  The  vein  which  returns  the  blood  of  the 
inferior  extremities  is  divided  in  the  pelvis 
into  two  branches,  which  correspond  with  the 
femoral  and  ischiadic  arteries;  the  one  passes 
through  the  ischiadic  foramen,  and  the  other 
through  the  hole  upon  the  anterior  margin  of 
the  pelvis;  but  the  proportion  they  bear  to 
each  other  in  magnitude  is  the  very  reverse  of 
what  occurs  in  the  arteries ;  for  the  anterior 
vein  is  the  principal  one,  whilst  the  other  is 
not  a  very  considerable  vessel,  and  receives  its 
supply  of  blood  from  the  muscles  at  the  pos- 
terior part  of  the  joint. 

"  The  femoral  vein  (a  «),  immediately  without 
the  pelvis,  gives  branches  on  both  sides,  which 
receive  the  blood  of  the  extensor  and  adductor 
muscles  at  their  superior  part :  the  trunk  passes 
obliquely  under  the  accessory  muscle  of  the 
flexor  digitorum,  and  over  the  os  femoris, 
where  it  liessuperficially ;  it  then  winds  under  the 
adductor  muscles,  and  gets  into  the  ham  (b  6), 
where  it  receives  many  muscular  branches, 
and  comes  into  company  with  the  artery  and 
nerve.  It  here  divides  into  the  tibial(c  c)  and 
peroneal  veins.  The  first  is  joined  by  some 
branches  from  the  surface  of  the  joint  answer- 
ing to  the  articular  arteries;  it  also  receives  the 
anterior  tibial  vein  which  accompanies  the 
artery  of  the  same  name.  The  tibial  vein  pro- 
ceeds down  the  leg  along  with  the  artery  on 
the  inside  of  the  deep-seated  flexors  of  the 
heel :  it  turns  over  the  fore  part  of  the  articu- 
lation of  the  tibia  with  the  metatarsal  bone, 
in  order  to  get  upon  the  inner  side  of  the  me- 
tatarsus; above  the  origin  of  the  pollex,  it 
receives  a  communicating  branch  from  the 
peroneal  vein,  and  immediately  after  two 
branches  from  the  toes:  one  of  them  comes 
from  the  inside  of  the  internal  toe ;  the  other 
arises  from  the  inside  of  the  external  and  mid- 
dle toes,  unites  at  the  root  of  the  toes  in  the 
sole  of  the  foot,  and  is  joined  by  a  branch  from 
the  pollex,  before  its  termination  in  the  internal 
vein  of  the  metatarsus. 

"  The  peroneal  vein  derives  its  principal 
branches  along  with  those  of  the  peroneal 
artery,  from  the  muscles  on  the  outside  of  the 
leg.  The  trunk  of  the  vein  comes  out  from 
the  peroneal  muscles,  and  passes  superficially 
over  the  joint  at  the  heel,  and  along  the  outside 
of  the  metatarsus ;  near  the  pollex,  or  great  toe, 
it  sends  a  branch  round  the  back  of  the  leg, 
to  communicate  with  the  tibial  vein ;  after 
which  it  is  continued  upon  the  outside  of  the 
external  toe  to  the  extremity,  receiving  anas- 
tomosing branches  from  the  tibial  vein. 

"  Where  the  veins  run  superficially  upon  the 
upper  and  lower  extremities,  they  seem  to 
supply  the  place  of  the  branches  of  the  cepha- 
lic, basilic,  and  the  two  saphena;  but  the 
analogy  is  lost  upon  the  upper  arm  and  thigh, 
these  branches  forming  deep-seated  trunks ; 
this  constitutes  the  greatest  peculiarity  in  the 
distribution  of  the  veins  in  the  extremities  of 
birds.1' 

Respiratory  organs. — In  the  course  of  this 


article  we  have  frequently  had  occasion  to  allude 
to  the  extent  and  activity  of  the  respiratory  func- 
tion in  the  Class  of  Birds;*  nevertheless  the 
organs  subservient  to  this  function  manifest 
more  of  the  peculiarities  of  the  Reptilian  than 
of  the  Mammalian  type  of  formation. 

The  lungs  are  confined,  as  in  the  Tortoise, 
to  the  back  part  of  the  thoracic-abdominal 
cavity,  being  firmly  attached  to  the  ribs  and 
their  interspaces ;  and,  as  in  the  Serpent,  they 
communicate  with  large  membranous  cells 
which  extend  into  the  abdomen  and  serve  as 
reservoirs  of  air. 

In  those  aquatic  Birds,  which  are  deprived 
of  the  power  of  flight,  as  the  Penguins,  the  air 
receptacles  are  confined  to  the  abdomen ;  but 
in  the  rest  of  the  class  they  extend  along  the 
sides  of  the  neck,  and,  escaping  at  the  chest  and 
pelvis,  accompany  the  muscles  of  the  extre- 
mities. They  also  penetrate  the  medullary 
cavities  and  diploe  of  the  bones,  extending  in 
different  species  through  different  proportions  of 
the  osseous  system,  until  in  some  birds,  as 
the  Horn-bill,  every  bone  of  the  skeleton  is 
permeated  by  air. 

There  is,  indeed,  no  class  of  Animals  which 
are  so  thoroughly  penetrated  by  the  me- 
dium in  which  they  live  and  move  as  that  of 
Birds.  Fig.  172. 

The  lungs  (w,  fig.  m) 
are  two  in  number,  of  a 
lengthened,  flattened,oval 
shape,  extending  along 
each  side  of  the  spine 
from  the  second  dorsal 
vertebra  to  the  kidneys, 
and  laterally  to  the  junc- 
tion of  the  vertebral  with 
the  sternal  ribs.  They 
are  not  suspended  freely 
as  in  Mammalia,  but  are 
confined  to  the  back  part ' 
of  the  chest  by  cellular 
membrane, and  the  pleura 
is  reflected  over  the  sternal 
surface  only,  to  which  the 
strong  aponeurosis  of  the  ^' 
diaphragmatic  muscles  is 
attached.  They  are  con- 
sequently smooth  and 
even  on  the  anterior  Ri9ht  Iun9  °f  a  Goo8e- 
surface,  but  posteriorly  are  accurately  moulded  to 
the  inequalities  of  the  ribs  and  intercostal  spaces. 

The  lungs  in  general  are  of  a  bright  red 
colour,  and  of  a  loose  spongy  texture.  The 
bronchi  (u,fig.  163;  a, Jig.  172)  penetrate  their 
mesial  and  anterior  surfaces  about  one-third 
from  the  upper  extremities;  they  divide  into 
four,  five,  or  six  branches,  which  diverge  as 
they  run  along  the  anterior  surface ;  some  in- 
complete cartilaginous  rings  are  found  through 
their  entire  extent. 

The  orifices  of  the  air-cells  of  the  lungs  (c  r, 
Jig.  172)  open  upon  the  posterior  parietes  of 
the  bronchial  tubes,  while  the  extremities  of 
these  tubes  terminate  by  wide  openings  (b  b, 
Jig.  172)  in  the  thoracic  and  abdominal  air- 
receptacles.  These  orifices  are  oblique,  ai.d 

*  According  to  Lavoisier,  two  Sparrows  consume 
as  much  oxygen  in  a  given  time  as  one  Guinea-pig. 


342 


AVES. 


are  partially  covered  by  a  slight  projection  of 
membrane. 

The  pulmonary  artery  divides,  almost  im- 
mediately after  its  origin,  into  two  branches, 
one  to  each  lung;  the  ramifications  of  each 
artery  form  plexuses  upon  the  air-cells,  and 
freely  anastomose  with  the  pulmonary  veins; 
these  leave  the  lung  by  a  single  trunk,  and 
the  two  pulmonary  veins  unite  into  one  before 
terminating  in  the  left  auricle. 

The  thoracic-abdominal  cavity  is  subdivided 
and  intersected  by  a  number  of  membranes; 
the  greater  part  of  the  cells  thus  formed  are 
filled  with  air.  The  texture  of  their  parietes 
possesses  considerable  firmness  in  the  larger 
birds,  as  the  Ostrich  and  Cassowary,  in  which 
they  were  described  by  the  French  Academi- 
cians as  so  many  distinct  bags. 

The  innermost  layer  of  the  air-receptacles 
can  be  separated  from  the  outer  layer,  and  is  a 
continuation  of  the  lining  membrane  of  the 
bronchial  tube;  the  outer  layer  is  a  serous 
membrane,  and  appears  to  form  the  cells  by  a 
series  of  reflections  of  what  may  be  regarded 
as  the  pleura  or  peritoneum. 

These  large  membranous  receptacles  into 
which  the  extremities  of  the  bronchial  tubes 
open  are  disposed  with  sufficient  general  regu- 
larity to  admit  of  a  definite  description  and 
nomenclature. 

Fig.  173. 


Air-receptacles  of  a  Swan. 


The  first  or  inter-clavicular  air-cell  («, 
173)  extends  from  the  anterior  part  of  ea< 
lung,  forwards  to  the  interspace  of  the  fur- 
culum,  anterior  to  which  it  dilates  in  the 
Gannet  and  many  other  birds  into  a  large 
globular  receptacle.  In  the  Vultures  it  is  di- 
vided into  two  lateral  receptacles,  between 
which  the  large  crop  is  situated.  A  thin  fan- 
shaped  muscle  is  extended  from  the  anterior 
edge  of  the  furculum,  over  the  interclavicular 
air-cell  in  these  and  some  other  birds 

The  anterior  thoracic  cell  (6)  contains  the 
lower  larynx  and  bronchi,  and  the  great  vessels 
with  their  primary  branches  to  the  head  and 
wings.  It  is  traversed  by  numerous  mem- 
branous septa,  which  connect  the  different 
vessels  together,  and  maintain  them  in  their 
situations.  The  air  passes  into  the  posterior 
part  of  this  receptacle  by  two  openings  at  the 
anterior  part  of  the  lungs.  The  deep-seated 
air-cells  of  the  neck  are  continued  from  it 
anteriorly. 

The  lateral  thoracic  cells  (d)  are  continued  on 
each  side  from  a  foramen  on  the  inner  edge  of 
the  lung,  situated  just  opposite  the  base  of  the 
heart ;  they  are  covered  by  the  anterior  tho- 
racic air-cell,  and  from  them  the  air  passes 
into  the  axillary  and  subscapular  cells,  into 
those  of  the  wing,  and  into  the  humerus  (e). 
They  also  communicate  with  the  cellula  cordis 
posterior  (c),  behind  the  heart  and  bronchi, 
which  cell  is  often  subdivided  into  several 
small  ones. 

The  cellula  hepatica  are  of  much  larger 
size ;  they  are  two  in  number,  of  a  pyramidal 
figure,  with  their  bases  applied  to  the  lateral 
thoracic  cells,  and  their  apices  reaching  to  the 
pelvis :  they  cover  the  lower  portions  of  the 
lungs  and  the  lobes  of  the  liver ;  they  receive 
air  from  several  foramina  situated  near  and  at 
the  external  edge  of  the  lungs. 

The  cellula  abdominales  commence  be- 
neath the  cellulse  hepaticae  at  the  inferior  ex- 
tremity of  the  lungs,  where  the  longest  branches 
of  the  bronchiae  open  freely  into  them.  (A 
bristle  is  passed  through  one  of  these  openings 
in  the  figure.)  They  are  distinguished  into 
right  (f)  and  left  (h) ;  the  former  is  gene- 
rally the  largest  receptacle  in  the  body ;  it  ex- 
tends from  the  last  ribs  to  the  anus,  and  covers 
the  greater  part  of  the  small  intestines,  the 
supra-renal  gland,  and  kidney  of  the  same 
side.  The  left  abdominal  cell  (A)  contains  the 
intestines  of  its  own  side,  and  is  attached  to 
the  gizzard.  In  some  large  Birds,  as  the 
Gannet,  it  is  separated  from  the  right  recep- 
tacle by  a  mediastinal  membrane  (g)  which  is 
continued  from  the  gizzard  to  the  anus. 

Both  the  abdominal  receptacles  transmit 
air  to  the  pelvic  cells  (i,  k)  of  their  respec- 
tive sides,  and  to  several  small  and  extremely 
delicate  cells  between  and  behind  the  coils  of 
intestine.  One  of  these  is  continued  round  the 
fold  of  the  duodenum  and  pancreas  to  the 
gizzard,  and  has  been  termed  the  duodenal 
cell. 

From  the  inguinal  cell  are  continued  the  in- 
termuscular  glut&al  and  femoral  cells,  which 
surround  the  head  of  the  femur,  and  commu- 
cate  with  that  bone  by  an  aperture  (1}  situated 


AVES. 


343 


immediately  anterior  to  .the  great  trochanter, 
except  in  those  Birds  in  which  the  femur 
retains  its  medulla. 

The  cervical  air-cells  are  continued  from  the 
large  clavicular  cell,  and  form  in  the  Argala  a 
singular  appendage  or  pouch,  contained  in  a 
loose  fold  of  integument,  which  the  bird  can 
inflate  at  pleasure. 

In  the  Pelecan  and  Gannet  extensive  air- 
cells  are  situated  beneath  almost  the  whole  of 
the  integument  of  the  body,  which  is  united  to 
the  subjacent  muscles  only  here  and  there  by 
the  septa  of  the  cells  and  the  vessels  and  nerves 
which  are  supported  by  the  septa  in  their  pas- 
sage to  the  skin.  The  large  pectoral  muscles 
and  those  of  the  thigh  present  a  singular  ap- 
pearance, being,  as  it  were,  cleanly  dissected 
on  every  side,  having  the  air-cavities  above  and 
beneath  them.  The  axillary  vessels  and  nerves 
are  also  seen  passing  bare  and  unsupported  by 
any  surrounding  substance  through  these  cavi- 
ties. Numerous  strips  of  panniculus  carnosus 
pass  from  various  parts  of  the  surface  of  the 
muscles  to  be  firmly  attached  to  the  skin ;  a 
beautiful  fan-shaped  muscle  is  spread  over  the 
inter-clavicular  or  furcular  air-cell.  The  use 
of  these  muscles  appears  to  be  to  produce  a 
rapid  collapse  of  the  superficial  air-cells,  and 
an  expulsion  of  the  air,  when  the  bird  is  about 
to  descend,  in  order  to  increase  its  specific 
gravity,  and  enable  it  to  dart  with  rapidity  upon 
a  living  prey. 

The  air-receptacles  of  the  thoracic-abdominal 
cavity  present  varieties  in  their  relative  sizes 
and  modes  of  attachment  in  different  birds.  In 
the  Raptores  they  are  principally  attached  pos- 
teriorly to  the  ribs,  the  diaphragmatic  aponeu- 
rosis  covering  the  lungs,  and  to  the  kidneys ; 
while  in  the  Grallatores  they  have  anterior 
attachments  to  the  intestines  in  many  places. 

The  singular  extension  of  the  respiratory 
into  the  osseous  system  was  discovered  almost 
simultaneously  by  Hunter  and  Camper,  and 
ably  investigated  by  them  through  the  whole 
class  of  Birds.  The  air-cells  and  lungs  can 
be  inflated  from  the  bones,  and  Mr.  Hunter 
injected  the  medullary  cavities  of  the  bones 
from  the  trachea.  It  is  stated  that  if  the  femur 
into  which  the  air  is  admitted  be  broken,  the 
bird  shall  not  be  able  to  raise  itself  in  flight. 
It  is  certain  that  if  the  trachea  be  tied,  and  an 
opening  be  made  into  the  humerus,  the  bird 
will  respire  by  that  opening  for  a  short  period, 
and  may  be  killed  by  inhaling  noxious  gases 
through  it.*  If  an  air-bone  of  a  living  bird, 
similarly  perforated,  be  held  in  water,  bubbles 
will  rise  from  it,  and  a  motion  of  the  contained 


*  "  I  cut  the  wing  through  the  os  humeri  in  a 
Fowl,  and  tying  up  the  trachea  found  that  the  air 
passed  to  and  from  the  lungs  by  the  canal  in  this 
bone.  The  same  experiment  was  made  with  the 
os  femoris  of  a  young  Hawk,  and  was  attended  with 
a  similar  result.  But  the  passage  of  air  through 
the  divided  parts,  in  both  these  experiments,  espe- 
cially in  the  last,  was  attended  with  more  difficulty 
than  in  the  former  one  ;  it  was  indeed  so  great,  as 
to  render  it  impossible  for  the  animal  to  live  longer 
than  evidently  to  prove  that  it  breathed  through 
the  cut  bone."—  Hunter's  Animal  (Economy,  p.  94. 


air  will  be  exhibited,  synchronous  with  the 
motions  of  inspiration  and  expiration. 

The  proportion  in  which  the  skeleton  is 
permeated  by  air  varies  in  different  Birds.  In 
the  Penguin  (Aptenodytcs),  which  we  have 
examined  for  this  purpose,  air  is  not  admitted 
into  any  of  the  bones.  Its  chief  progression  being 
in  water,  the  specific  levity  of  the  body  gained 
by  the  substitution  of  air  for  marrow  would  be 
rather  a  detriment  than  an  advantage.  The 
condition  of  the  osseous  system,  therefore,  which 
all  birds  present  at  the  early  periods  of  exist- 
ence, is  here  retained  through  life. 

In  the  large  Struthious  Birds,  which  are  re- 
markable for  the  rapidity  of  their  course,  the 
thigh-bones  and  bones  of  the  pelvis,  the  ver- 
tebral column,  ribs,  sternum  and  scapular 
arch,  the  cranium  and  lower  jaw,  have  all  air 
admitted  into  their  cavities  or  cancellous  struc- 
ture. The  humeri  and  other  bones  of  the 
wings,  the  tibiae  and  distal  bones  of  the  legs, 
retain  their  marrow. 

With  the  exception  of  the  Woodcock,  all 
Birds  of  Flight  have  air  admitted  to  the 
humerus. 

The  Pigeon  tribe,  with  the  exception  of  the 
Crown  Pigeon,  have  no  air  in  the  femur,  which 
relains  its  marrow.  In  the  Owls  also  the  femur 
is  filled  with  marrow;  but  in  the  Diurnal  Birds 
of  Prey,  as  in  almost  all  other  Birds  of  Flight, 
the  femur  is  filled  with  air. 

In  the  Pelecan  and  Gannet  the  air  enters  all 
the  bones  with  the  exception  of  the  phalanges 
of  the  toes.  In  the  Hornbill  even  these  are 
permeated  by  air. 

Mr.  Hunter*  has  given  the  following  cha- 
racters as  distinguishing  the  bones  which  receive 
air.  They  may  be  known — "  first,  by  their 
less  specific  gravity ;  secondly,  by  their  retain- 
ing little  or  no  oil,  and,  consequently,  being 
more  easily  cleaned,  and  when  cleaned,  ap- 
pearing much  whiter  than  common  bones : 
thirdly,  by  having  no  marrow,  or  even  any 
bloody  pulpy  substance  in  their  cells  ;  fourthly, 
by  not  being  in  general  so  hard  and  firm  as 
other  bones ;  and,  fifthly,  by  the  passage  that 
allows  the  air  to  enter  the  bones,  which  can 
easily  be  perceived." 

We  have  reserved  for  this  section  the  de- 
scription of  the  foramina  by  which  the  air 
penetrates  the  different  bones.  These  openings 
may  be  readily  distinguished  in  the  recent 
bone,  since  they  are  not  filled  up  by  blood- 
vessels or  nerves,  but  have  their  external  edges 
rounded  off. 

In  the  dorsal  vertebrae  the  air-orifices  are 
small,  numerous,  and  irregular ;  situated  along 
the  sides  of  the  bodies,  and  the  roots  of  the 
spinous  processes,  the  air  passes  into  them 
directly  from  the  lungs.  In  the  two  or  three 
lower  cervical  vertebrae  the  air-holes  are  in  the 
same  situation,  but  receive  the  air  from  the 
lower  cervical  or  clavicular  air-cells :  in  the 
remainder  of  these  vertebrae  the  air-holes  are 
situated  within  the  canal  lodging  the  vertebral 
artery,  and  communicate  with  the  lateral  air- 
cells  of  the  neck. 

*  Animal  (Economy,  p.  91. 


344 


AVES. 


The  air-holes  of  the  vertebral  ribs  are  situated 
at  the  internal  surface  of  their  vertebral  extre- 
mities, and  appear  like  those  of  the  contiguous 
vertebrae  to  have  an  immediate  communication 
with  the  lungs.  The  sternal  ribs,  or  ossified  costal 
cartilages,  have  also  internal  cavities  which 
receive  air  from  the  lateral  thoracic  cells  by 
means  of  orifices  placed  at  their  sternal  ex- 
tremities. 

The  orifices  by  which  air  is  admitted  to  the 
sternum  are  exceedingly  numerous,  but  are 
principally  situated  along  the  mesial  line  of  the 
internal  surface,  opposite  the  origin  of  the 
keel,  forming  a  reticulation  at  that  part;  the 
largest  foramen  is  near  the  anterior  part  of 
the  bone ;  some  smaller  ones  occur  at  the 
costal  margins.  All  these  orifices  commu- 
nicate with  the  thoracic  air-receptacles. 

The  scapula  is  perforated  by  several  holes 
at  the  articular  extremity,  which  admit  air 
into  its  cancellous  structure  from  the  axillary 
cell. 

The  coracoid  has  small  air-holes  at  both  ex- 
tremities ;  the  largest  is  situated  on  its  inner 
surface,  where  it  is  connected  with  the  clavicle 
or  furculum. 

The  furculum  receives  air  principally  by  a 
small  hole  in  the  inner  side  of  each  of  its 
scapular  extremities,  which  communicates  with 
the  clavicular  air-celL 

The  air-hole  of  the  humerus  is  of  large  size, 
and  situated  at  the  back  part  of  the  head  of 
the  bone,  below  the  curved  inferior  process. 
It  communicates  with  the  axillary  air-cell,  and 
transmits  the  air  to  the  cavity  of  the  bone  by 
several  cribriform  foramina. 

The  air-holes  of  the  pelvic  bones  are  situated 
irregularly  on  the  inner  surface  upon  which  the 
kidneys  rest,  and  must  therefore  receive  air 
from  continuations  of  the  abdominal  receptacles 
around  the  kidneys. 

The  air-hole,  or  rather  air-depression  of  the 
femur,  is  situated  at  the  anterior  part  of  the 
base  of  the  trochanter;  it  receives  air  from  the 
glutaeal  cell,  and  transmits  it  by  several  small 
foramina  into  the  interior  of  the  bone.  In 
the  Ostrich,  the  air-holes  are  situated  at  the 
posterior  part  of  the  bone  at  both  of  its  extre- 
mities. 

The  cavities  of  the  long  bones  into  which 
air  is  thus  admitted  are  proportionally  larger 
than  in  the  corresponding  bones  of  Mammalia, 
and  are  characterized  by  small  transverse 
osseous  columns  which  cross  in  different  di- 
rections from  side  to  side,  and  are  more  nu- 
merous near  the  extremities  of  the  bone ;  they 
abut  against  and  strengthen,  like  cross-beams, 
the  parietes  of  the  bone. 

We  have  sometimes  succeeded  in  filling  with 
fine  size-injection  the  minute  arteries  which 
ramify  on  the  membrane  lining  these  cavities, 
but  the  vascularity  of  this  membrane  is  by  no 
means  very  remarkable. 

The  lower  jaw  receives  its  air  by  means  of 
an  orifice  situated  upon  each  ramus  behind  the 
tympano-maxillary  articulation.  Mr.  Hunter 
was  in  doubt  as  to  whether  the  lower  jaw 
derived  its  supply  of  air  from  the  Eustachian 
tube  or  the  trachea  where  it  passes  along  the 


neck.*  In  a  Pelecan  which  we  dissected  for 
the  purpose  we  found  it  to  be  supplied  by  an 
air-cell  which  surrounded  the  joint,  and  was  con- 
tinuous with  the  upper  cervical  air-cells.  The 
bones  of  the  cranium  and  upper  jaw  have  com- 
munications with  the  Eustachian  tube,  but  not 
with  the  nasal  passages,  which  are  every  where 
lined  with  an  impervious  pituitary  membrane. 

Various  explanations  have  been  given  of  the 
final  intention  of  the  condition  of  the  respiratory 
system  above  described. 

The  extension  of  this  system  by  means  of 
continuous  air-receptacles  throughout  the  body 
is  subservient  to  the  function  of  respiration, 
not  only  by  a  change  in  the  blood  of  the 
pulmonary  circulation  effected  by  the  air  of  the 
cells  on  its  re-passage  through  the  bronchial 
tubes,  but  also,  and  more  especially,  by  the 
change  which  the  blood  undergoes  in  the  ca- 
pillaries of  the  systemic  circulation,  which  are 
in  contact  with  the  air-receptacles.  The  free 
outlet  to  the  air  by  the  bronchial  tubes  does 
not,  therefore,  afford  an  argument  against  the 
use  of  the  air-cells  as  subsidiary  respiratory 
organs,  but  rather  supports  that  opinion,  since 
the  inlet  of  atmospheric  oxygenated  air  to  be 
diffused  over  the  body  must  be  equally  free. 

A  second  use  may  be  ascribed  to  the  air- 
cells  as  aiding  mechanically  the  actions  of 
respiration  in  Birds.  During  the  act  of  inspi- 
ration the  sternum  is  depressed,  the  angle 
between  the  vertebral  and  sternal  ribs  made 
less  acute,  and  the  thoracic  cavity  proportion- 
ally enlarged ;  the  air  then  rushes  into  the 
lungs  and  into  the  thoracic  receptacles,  while 
those  of  the  abdomen  become  flaccid  :  when 
the  sternum  is  raised  or  approximated  towards 
the  spine,  part  of  the  air  is  expelled  from  the 
lungs  and  thoracic  cells  by  the  trachea,  and 
part  driven  into  the  abdominal  receptacles, 
which  are  thus  alternately  enlarged  and  dimi- 
nished with  those  of  the  thorax. .  Hence  the 
lungs,  notwithstanding  their  fixed  condition, 
are  subject  to  due  compression  through  the 
medium  of  the  contiguous  air-receptacles,  and 
are  affected  equally  and  regularly  by  every 
motion  of  the  sternum  and  ribs. 

A  third  use,  and  perhaps  the  one  which  is 
most  closely  related  to  the  peculiar  exigences 
of  the  bird,  is  that  of  rendering  the  whole 
body  specifically  lighter ;  this  must  necessarily 
follow  from  the  dessication  of  the  marrow  and 
other  fluids  in  those  spaces  which  are  occupied 
by  the  air-cells,  and  by  the  rarefaction  of  the 
contained  air  from  the  heat  of  the  body. 

Agreeably  to  this  view  of  the  function  of  the 
air-cells,  it  is  found  that  the  quantity  of  air 
admitted  into  the  system  is  in  proportion  to  the 
rapidity  and  continuance  of  the  bird's  motion; 
and  that  the  air  is  especially  distributed  to  those 
members  which  are  most  employed  in  loco- 
motion ;  thus  the  air  is  admitted  into  the  wing- 
bones  of  the  Owl,  but  not  into  the  femur; 
while  in  the  Ostrich  the  air  penetrates  the 
femur,  but  not  the  humerus  or  other  bones  of 
the  wing. 

A  fourth  use  of  the  air-receptacles,  which 
has  not  hitherto  been  suspected,  relates  to  the 
*  Loc.  cit.  p.  93. 


AYES. 


315 


mechanical  assistance  which  they  afford  to  the 
muscles  of  the  wings.  This  was  first  suggested 
to  us  by  observing  that  an  inflation  of  the  air- 
cells  in  a  Gigantic  Crane  (Ciconia  Argala) 
was  followed  by  an  extension  of  the  wings,  as 
the  air  found  its  way  along  the  brachial  and 
anti-brachial  cells.*  In  large  birds,  therefore, 
which,  like  the  Argala,  hover  with  a  sailing 
motion  for  a  long-continued  period  in  the 
upper  regions  of  the  air,  the  muscular  exertion 
of  keeping  the  wings  outstretched  will  be  les- 
sened by  the  tendency  of  the  distended  air-cells 
to  maintain  that  condition.  It  is  not  meant  to 
advance  this  as  any  other  than  a  secondary 
and  probably  partial  use  of  the  air-cells.  In 
the  same  light  may  be  regarded  the  use  as- 
signed to  them  by  Hunter,  of  contributing  to 
sustain  the  song  of  Birds,  and  to  impart  to  it 
tone  and  strength.  It  is  no  argument  against  this 
function  that  the  air-cells  exist  in  birds  which 
are  not  provided  with  the  mechanism  necessary 
to  produce  tuneful  notes ;  since  it  was  not  pre- 
tended by  Hunter  that  this  was  the  exclusive 
and  only  office  of  the  air-cells.  The  latest 
writer  on  this  subject  has  indeed  proposed  this 
suggestion  of  Mr.  Hunter  as  a  novel  idea.f 

Air-passages. — The  air-passages  in  birds 
commence  by  a  simple  superior  larynx,  from 
which  a  long  trachea  extends  to  the  anterior 
aperture  of  the  thorax,  where  it  divides  into 
the  two  bronchi,  one  to  each  lung.  At  the 
place  of  its  division  there  exists,  in  most  birds, 
a  complicated  mechanism  of  bones  and  carti- 
lages moved  by  appropriate  muscles,  and 
constituting  the  true  organ  of  voice  :  this  part 
is.  termed  the  inferior  larynx. 

The  tendency  to  ossification,  which  is  ex- 
emplified in  the  bony  condition  of  the  costal 
cartilages  and  tendons  of  the  muscles,  is  again 
manifested  in  the  framework  of  the  larynx  and 
the  rings  of  the  trachea,  which,  instead  of 
being  cartilaginous,  as  in  Reptiles  and  Mam- 
mals, are  in  most  birds  of  a  bony  texture. 

The  superior  larynx  (Jig.  151,  174,  175,) 
is  situated  behind  the  root  of  the  tongue,  and 
rests  upon  the  uro-hyal  element  of  the  os  hy- 
oides,  to  which  it  is  attached  by  dense  cellular 
texture. 

It  is  composed  of  several  bony  and  cartila- 
ginous pieces,  varying  in  number  from  four  to 
ten.  The  largest  oi  these  pieces  constitutes 
the  anterior  part  of  the  larynx.  It  is  of 
an  oval  or  triangular  form,  according  as.  its 
superior  termination  is  more  or  less  pointed : 
it  is  regarded  by  Cuvier  as  analogous  to 
the  anterior  part  of  the  cricoid  cartilage, 
(Lecons  d'Anat.  Comp.  iv.  p.  489,)  but  by 
Carus  it  is  considered  as  representing  the 
thyroid  cartilage  (fy  fig.  151).  The  cricoid 
cartilage  in  birds  consists  of  the  three  osseous 
pieces,  which  are  situated  at  the  posterior 

*  On  relating  this  fact  to  Mr.  Clift,  he  suggested 
another  use  of  the  air-cells  which  is  more  generally 
applicable,  namely,  that  of  assisting  the  actions  of 
the  muscles  by  compressing  and  bracing  them,  in  a 
manner  analogous  to  the  action  of  the  fasciae  of  the 
extremities  in  Man. 

t  Jacquemin,  Memoirc  sur  la  pneumaticitc  des 
oiseaux,  1835. 


Fig.  174. 


and  inferior  part  of  the  upper  larynx;  the 
middle  one  (g,Jig.  151)  is  of  an  oblong  form, 
and  varies  in  size,  being  larger  than  the  lateral 
ones  in  the  Anatida,  but  smaller  in  the  In- 
scssores.  The  lateral  pieces  are  connected  at 
one  extremity  with  the  thyroid  piece,  and  at 
the  other  to  the  middle  oblong  piece  above 
described,  which  completes  the  circle  of  the 
laryngeal  frame-work  posteriorly.  Carus  re- 
gards the  first  two  incomplete  tracheal  rings 
(gg)  as  the  anterior  part  of  the  cricoid.  The 
arytenoid  bones  (h)  rest  upon  the  middle  ob- 
long portion  of  the  cricoid,  and  extend  for- 
wards, being  connected  at  their  outer  edge  by 
means  of  elastic  cellular  substance  to  the  thy- 
roid bone,  and  attached  by  their  anterior  ex- 
tremities to  the  uro-hyal  bone  by  means  oi" 
two  small  ligaments  :*  they  form,  by  their  inner 
margins,  the  rima  glottidis  or  laryngeal  fissure. 
This  fissure  (i,fig.  152)  being  thus  bounded 
by  inflexible  rigid  substances  is  only  susceptible 
of  having  its  lateral  diameter  varied  according 
to  the  degrees  of  separation  or  approximation  to 
which  the  arytenoid  bones  are  subject.  These 
different  states  are  produced  by  (appropriate 
muscles,  one  pair  of  which  may  be  regarded 
as  analogous  to  the  Thyreo-arytcnoidei,  and  the 
other  may  be  termed  Constrictores  glottidis. 
The  former  of  these  muscles  (k  k,Jig.  174,) 
arise  from  the  sides  and  posterior  surface  of 
the  thyroid  bone,  and  are 
inserted  into  the  whole 
length  of  the  inner  edge 
of  the  arytenoid  cartilages, 
which  they  draw  out- 
wards, and  consequently 
open  the  laryngeal  fissure, 
The  constrictores  glottidis 
in  the  Gigantic  Crane  arise 
from  the  middle  of  the  in- 
ternal or  posterior  surface 
of  the  thyroid  bone,  and  are 
inserted  into  the  extremi- 
ties of  the  arytenoid  pieces. 
According  to  Mr.  Yarrell, 
from  whose  Memoir  the  subjoined  figures  are 
taken,  the  constrictors  of  the  glottis  (l,fig.175) 
"  pass  from  the  upper  portion  of  the  cricoid 
(thyroid)  cartilage  along  the  cru'ra  of  the  ary- 
tenoid cartilages,  upon  each  outer  edge  of 
which  they  are  inserted ."-f 
In  either  case  these  muscles 
are  enabled  to  close  the  la- 
ryngeal opening  with  con- 
siderable force,  and  with 
such  accuracy  as  to  super- 
sede the  necessity  of  an 
epiglottis.  From  the  sim- 
plicity of  the  structure  just 
described,  from  the  situation 
of  the  superior  larynx  with 
relation  to  the  rictus  or  gape 
of  the  bill,  and  from  the 
absence  of  lips  by  which 
this  might  be  partially  or 

*  Linn.  Trans,  vol.  xvi.  p.  £06,  pi.  17,  figs. 
3  and  4. 

t  This  description  is  taken  from  the  Gigantic 
Crane.  —  Ciconia  Argala. 


Fig.  175. 


346 


AVES. 


entirely  closed,  it  is  plain  that  it  cannot  be 
considered  as  influencing  the  voice,  otherwise 
than  by  dividing  or  articulating  the  notes 
after  they  are  formed  by  the  lower  larynx. 
The  superior  larynx  presents,  indeed,  but  few 
varieties  in  the  different  species  of  Birds ;  and 
these  relate  chiefly  to  certain  tubercles  which 
are  observed  in  its  anterior,  but  which  vary  in 
number,  and  do  not  exist  at  all  in  some  spe- 
cies, as  the  singing  birds ;  being  chiefly  pre- 
sent in  those  birds  which  have  a  rough  un- 
musical voice.  In  the  Pelecan,  the  Gigantic 
Crane,  and  most  of  the  Rasores,  a  process  ex- 
tends backwards  into  the  cavity  of  the  upper 
larynx  from  the  middle  of  the  posterior  surface 
of  the  thyroid  cartilage,  and  seems  destined 
to  give  additional  protection  to  the  air-passage. 
The  trachea  (G,Jig.  170,  171)  in  Birds  is 
proportionally  longer,  in  consequence  of  the 
length  of  the  neck,  than  in  any  other  class  of 
animals,  its  length  being  further  increased  in 
many  species  by  convolutions  varying  in  extent 
and  complexity.  A  species  of  Sloth  (Bradypus 
tridactylus)  among  Mammalia,  and  a  species  of 
Crocodile  (Crocodilus  acutus)  among  Reptiles, 
present  an  analogous  folding  of  the  trachea. 

The  trachea  is  composed  in  Birds  of  a 
series  of  bony,  and  sometimes,  as  in  the 
Ostrich,  of  cartilaginous  rings,  included  be- 
tween two  membranes.  In  those  cases  in 
which  they  are  of  a  bony  structure,  the  ossi- 
fication is  observed  to  commence  at  the  anterior 
part  of  each  ring,  and  gradually  to  extend  on 
both  sides  to  the  opposite  part. 

The  tracheal  rings,  whether  bony  or  cartila- 
ginous, are,  with  the  exception  of  the  two 
uppermost,  always  complete,  and  not,  as  in 
most  quadrupeds,  where  the  windpipe  bears  a 
different  relation  to  the  organ  of  voice,  defi- 
cient posteriorly.  They  differ  in  shape,  being 
sometimes  more  or  less  compressed.  They 
are  generally  of  uniform  breadth,  but  in  some 
species  are  alternately  narrower  at  certain  parts 
of  their  circumference  and  broader  at  others, 
and  in  these  cases  the  rings  are  generally 
closely  approximated  together,  and,  as  it  were, 
locked  into  one  another.  This  structure  is 
most  common  in  the  Grallatores,  where  the 
rings  are  broadest  alternately  on  the  right  and 
left  sides :  the  French  Academicians  have  given 
a  good  illustration  of  this  structure  from  the 
trachea  of  the  Demoiselle  Crane. 

With  respect  to  the  diameter  of  the  tracheal 
rings,  this  may  sometimes  be  pretty  uniform 
throughout,  and  the  trachea  will  consequently 
be  cylindrical,  as  in  the  Insessores,  the  Gralla- 
tores which  have  a  shrill  voice,  the  females  of 
the  Natatores,  and  most  Raptores  and  Ra- 
sores: or  the  rings  may  gradually  decrease  in 
diameter,  forming  a  conical  trachea,  as  in  the 
Turkey,  the  Heron,  the  Buzzard,  the  Eagle, 
the  Cormorant,  and  the  Gannet ;  or  they  may 
become  wider  by  degrees  to  the  middle  of  the 
trachea,  and  afterwards  contract  again  to  the 
inferior  larynx ;  or,  lastly,  they  may  experience 
sudden  dilatations  for  a  short  extent  of  the 
trachea; — the  Golden-eye  (Anasclangula),  the 
Velvet-duck  (Anas  fusca),  and  the  Mergan- 
ser (Mergus  sermtor),  present  a  single  en- 


largement of  this  kind,  in  which  the  bony 
rings  are  entire,  and  of  the  same  texture  as  in 
the  rest  of  the  tube.  In  the  Golden-Eye  the 
trachea  is  four  times  larger  at  the  dilatation 
than  at  any  other  part.  In  the  Goosander 
(  Mergus  merganser),  the  trachea  presents  two 
sudden  dilatations  of  a  similar  structure  to  that 
above  described.  The  trachea  of  the  Emeu 
(Dromaius  ater)  is  also  remarkable  for  a  sud- 
den dilatation,  but  in  this  instance  the  cartila- 
ginous rings  do  not  preserve  their  integrity  at  the 
dilated  part,  but  are  wanting  posteriorly,  where 
the  tube  is  completed  by  the  membranes  only. 
The  bronchi  (v,  jig.  163)  are  straight,  com- 
pressed, delicate,  and  easily  lacerable  tubes; 
their  rings,  in  most  Birds,*  form  only  a  small 
segment  of  a  circle,  and  are  situated  at  the 
outer  side  of  the  tube,  which  is  convex ;  the 
inner  side  is  completed  by  a  membrane  (mem- 
brana  tympaniformis)  extended  between  the 
extremities  of  the  defective  rings,  and  is  flat. 
The  bronchial  rings  are  weak  and  thin ;  in 
Birds  without  true  muscles  of  voice,  they  are 
either  of  uniform  thickness,  or  become  gradually 
thinner  to  their  termination :  in  many  Birds 
which  have  the  vocal  muscles  they  grow  sud- 
denly thinner  below  the  insertion  of  those 
muscles :  this  is  remarkable  in  Owls. 

The  muscles  of  the  trachea  are  generally  a 
single  pair,  the  sterno-tracheales,  to  which,  in 
some  cases,  a  second  pair  is  added,  the  cleido- 
tracheales.  The  sterno-tracheales,  which  are 
analogous  to  the  sterno-thyroidei  of  mammalia, 
arise  from  the  costal  processes  of  the  sternum, 
and  ascend  along  the  sides  of  the  trachea,  as 
far  in  general  as  the  superior  larynx.  The 
cleido-tracheales  (ypsilo-tracheens  of  Cuvier) 
arise  from  the  furculum  or  conjoined  clavicles, 
and  pass  along  the  sides  of  the  trachea  parallel 
to  the  preceding. 

Many  birds  possess  only  the  tracheal  and 
superior  laryngeal  muscles,  and  have  no  proper 
muscles  of  the  inferior  larynx.  Cuvierf  divides 
such  birds  into  those  which  have  the  lower 
larynx  simple  or  without  dilatations,  as  the 
Rasores,  and  into  those  which  have  lateral 
bony  cavities  at  that  part,  as  the  males  of  the 
Genus  Anas,  Cuv.  and  Mergus. 

His  next  division  in  the  order  of  complexity 
of  the  vocal  organs  includes  those  birds  which 
have  one  pair  of  vocal  or  inferior  laryngeal 
muscles,  the  Broncho-tracheales ;  these  arise 
from  the  sides  of  the  lower  part  of  the  trachea, 
and  are  inserted  in  one  of  the  half-rings  of  the 
bronchi  at  a  less  or  greater  distance  from  the 
lower  larynx  in  different  birds ;  as,  for  exam 
pie,  in  the  first  half-ring  in  the  Genus  Falco, 
in  most  of  the  Grallatores,  in  the  Genus 
Larus  (Gull),  and  Phalacrocorax  (Cormo- 
rant) ;  in  the  third  half-ring  in  the  King-fisher 
(Alcedo),  and  Goat-sucker  ( Caprimulgus ) ; 
in  the  fifth  half-ring  in  the  Genus  Ardea,  Cuv. 
in  the  Cuckoo  and  the  Eagle-Owl  (Bubo 
maximus);  in  the  seventh  half-ring  in  the 

*  In  the  Vultures,  which  have  no  true  vocal 
muscles,  but  only  the  sterno-tracheales,  the  first  four 
bronchial  rings  are  entire. 

t  Anat.  Comparee,  torn.  iv.  p.  450. 


AVES. 


347 


Barn-Owl  (Strix  flammea)  and  Horn-Owl 
(Otus  uurita).  The  influence  of  these  muscles 
upon  the  voice  must  obviously  be  in  proportion 
as  they  shorten  the  bronchi  and  depress  the 
lower  larynx,  according  to  the  different  inser- 
tions above  mentioned. 

A  further  degree  of  complexity  in  the  organ 
of  voice  is  presented  by  the  Psittacida  or  Par- 
rot-tribe, which,  according  to  Cuvier,  have  three 
pairs  of  inferior  laryngeal  muscles. 

The  Insessores,  lastly,  present  five  pairs  of 
muscles  appertaining  to  the  lower  larynx,  and  the 
organ  of  voice  consequently  attains  its  greatest 
perfection  in  this  order. 

The  peculiar  structure  of  the  lower  larynx, 
and  the  modifications  of  the  trachea  in  relation 
to  its  functions,  will  be  treated  of  under  the 
article  Organs  of'  Voice. 

Urinary  Organs. — These  consist  in  birds  of 
the  kidneys,  ureters,  and  a  urinary  receptacle, 
which  is  more  or  less  developed  in  all  birds. 

The  kidney  of  the  oviparous  vertebrate  ani- 
mal is  distinguished  from  that  of  the  mammi- 
ferous  by  the  homogeneity  of  its  substance, 
which  is  not  divided  into  a  cortical  and  medul- 
lary part,  and  by  the  tubuli  uriniferi  extending 
to  the  surface  of  the  gland  there  to  form  by 
reiterated  unions  the  ureter,  and  not  terminating 
in  a  cavity  or  pelvis  in  the  interior  of  the  kidney, 
from  which  the  ureter  commences. 

The  kidneys  (x  x,  fig.  182)  of  birds  manifest 
all  the  essential  characters  of  the  oviparous  type 
of  structure.  They  are  two  in  number,  of  an  elon- 
gated form,  commencing  immediately  below  the 
lungs,  and  extending  along  the  sides  of  the  spine 
as  far  as  the  termination  of  the  rectum ;  in  which 
course  they  are  impacted  in,  and  as  it  were 
moulded  to  the  cavities  and  depressions  of  the 
pelvis.  From  this  fixed  condition  it  results  that 
they  are  generally  symmetrical  in  position,  not 
placed  one  higher  than  the  other,  as  in  the  mam- 
malia. The  posterior  surface  of  the  kidney  pre- 
sents inequalities  corresponding  to  the  risings 
and  depressions  of  the  pelvis;  the  anterior  sur- 
face is  smoothly  convex  or  flattened  ;  but  rising 
into  a  series  of  prominences  which  correspond, 
not  to  the  eminences,  but  to  the  cavities  of  the 
bones  on  which  they  rest :  their  inner  or  mesial 
side  is  generally  pretty  regular  and  straight,  but 
the  external  edge  is  more  or  less  notched. 

From  the  nature  of  the  integuments  about  to 
be  described,  and  the  small  amount  of  cutane- 
ous transpiration  in  birds,  the  office  of  removing 
from  the  system  the  superfluous  watery  part  of 
the  circulating  fluids  devolves  almost  exclu- 
sively upon  the  kidneys,  and  they  are  conse- 
quently relatively  larger  than  in  the  terrestrial 
mammalia. 

The  kidneys  vary  in  size  in  different  birds, 
being  for  example  smaller  in  most  of  the 
Grallatores,  as  the  Bustard  and  Heron,  where 
the  pelvis  is  short,  than  in  the  Rasorial 
Order,  in  which  it  is  of  great  extent.  Where 
they  are  short  they  are  in  general  more  promi- 
nent, and  this  is  so  remarkable  in  some  birds, 
as  the  Owls,  that  in  them  they  resemble  some- 
what in  their  superficial  position  the  kidneys  of 
mammalia. 


As  might  be  expected  from  their  relations 
to  the  pelvis,  the  kidneys  in  birds  present  as 
many  varieties  of  outward  configuration  as 
there  are  differences  in  the  part  of  the  skeleton 
to  which  they  are  moulded.  In  some  aquatic 
birds,  as  the  Grebe  ( PodicepsJ  and  the  Coot 
(Fulica),  the  kidneys  are  more  or  less 
blended  together  at  their  lower  extremities,  as 
in  most  fishes.  In  the  rest  of  the  class  they  are 
distinct  from  one  another. 

In  the  Tern  they  are  each  divided  by  fissures 
into  seven  or  eight  square-shaped  lobes.  In 
the  Eagle  they  each  present  four  divisions ;  but 
in  these  cases  there  are  not  distinct  ureters  to 
each  lobe  as  in  the  subdivided  kidneys  of  mam- 
malia. 

The  principal  lobes  are  in  general  three  in 
number,  the  anterior  or  highest  one  being,  in 
some  cases,  the  largest;  while  in  others,  as 
the  Pelecan,  the  contrary  obtains,  the  lowest 
division  being  most  developed  in  this  bird. 

In  the  Emeu  (Dromaius  ater)  the  kidney 
presents  only  two  lobes;  the  superior  or  anterior 
one  is  the  broadest  and  most  prominent,  being 
of  a  rounded  figure,  and  constituting  one-third 
of  the  whole ;  the  lower  division  is  flattened, 
and  gradually  tapers  to  a  point.  In  the  speci- 
men we  dissected  we  found  the  left  kidney  half 
an  inch  longer  than  the  right. 

Each  kidney  is  invested  by  its  proper  capsule, 
a  thin  membrane,  which  also  extends  into  the 
substance  of  the  gland,  between  its  divisions :  a 
delicate  layer  of  peritoneum  is  reflected  over 
their  anterior  surfaces. 

The  texture  of  the  kidneys  is  much  more  frail 
than  in  mammalia,  readily  yielding  under  the 
pressure  of  the  finger,  to  which  they  give  a  granu- 
lar sensation  as  their  substance  is  torn  asunder. 

In  colour  they  resemble  the  human  spleen. 
Besides  being  divided  into  lobes,  the  surface  of 
the  kidneys  may  be  observed  to  be  composed  of 
innumerable  small  lobules,  separated  by  conti- 
nuous gyrations  like  the  convolutions  of  the 
cerebral  substance.  The  ultimate  divisions  of 
the  lobules  and  their  intimate  structure  can 
only  be  distinguished  by  observations  on  the 
embryo,  unless  when  the  component  follicles 
are  filled,  as  they  occasionally  are  seen  to  be 
after  death,  with  the  white  salts  of  the  urinary 
secretion.  The  tubuli  uriniferi,  as  Miiller  ob- 
serves,* may  then  be  seen  under  the  microscope 
originating  from  every  part  of  the  internal  sub- 
stance of  the  lobules,  extending  to  the  gyrations, 
uniting  in  the  pinnatifid  form,  and  coursing  to 
the  margins  of  the  lobules,  all  the  inflexions  of 
which  they  follow.  The  pinnatifid  ramification 
of  the  uriniferous  tubules  is  sometimes  opposite, 
sometimes  alternate.  Sometimes  the  branches 
are  simple,  sometimes  dichotomously  divided : 
but  these  ramuli  appear  scarcely  smaller  than 
the  branches  from  which  they  spring,  and  never 
intercommunicate.  They  have  been  successfully 
injected  with  size  and  vermilion,  without  any 
of  this  material  escaping  into  the  secerning 
vessels,  which  are  much  more  minute.  The 
uriniferous  ducts,  when  thus  traced  from  the 

*  De  Glandularum  Structura,  p.  92. 


348 


AVES. 


irunks  to  the  branches,  are  seen  to  become  con- 
fined in  pyramids,  which  adhere  to  the 
branches  of  the  ureter,  are  sent  out  in  the  gyri 
of  the  lobules,  and  are  outspread  in  a  pinnatifid 
figure  on  the  surface,  one  next  another,  and 
ultimately  terminate  in  blind,  rounded,  but  not 
dilated  extremities.  The  branches  from  the 
convoluted  lobules  unite  dichotomously,  and 
ultimately  escape  by  a  single  duct — the  ureter. 

The  arteries  and  veins  of  the  kidneys  have 
already  been  described ;  a  difference  of  opinion, 
however,  prevails  as  to  the  course  of  the  blood 
in  the  veins  which  pass  from  the  lower  end  of  the 
kidneys  (at  v,fg.  171)  to  the  hypogastric  vein 
(*).  Jacobson  considers  that  the  venous  blood 
is  carried  into  the  kidney  by  these  veins,  for  the 
purpose  of  affording  the  material  for  the  urinary 
secretion,  analogous  to  the  portal  vein  in  the 
liver ;  but  Cuvier  regards  these  veins  as  having 
the  same  function  as  those  which  come  from 
the  upper  ends  of  the  kidneys,  and  that  they 
return  the  blood  from  the  lower  ends  of  the 
kidneys  to  aid  in  the  formation  of  the  portal 
vein.  Nicolai*  also  opposes  the  doctrine  of  a 
venous  circulation  in  the  kidneys  of  Birds. 
In  favour  of  Jacobson's  theory  is  the  small 
size  of  the  renal  arteries,  in  consequence  of 
which  the  kidneys  are  not  more  coloured 
than  the  liver,  when  the  arterial  system  is  in- 
jected from  the  aorta,  and  the  disproportionate 
size  of  the  veins,  together  with  the  analogy  of 
the  cold-blooded  ovipara,  in  which  the  exist- 
ence of  a  secreting  system  of  veins  in  the  kid- 
neys is  now  generally  admitted. 

The  ureter  (y,fig.  163,  182;  h,  k,fig.  176) 
lias  the  same  structure  as  in  the  mammalia.  It 
is  continued  down  along  the  anterior  surface  of 
the  kidney  towards  the  mesial  side ;  here  and 
there  imbedded  in  its  substance,  forming  a 
series  of  dilatations  corresponding  to  the  prin- 
cipal lobes  or  enlargements  of  the  gland,  and 
receiving  the  branches  of  the  tubuli  uriniferi  as 
it  passes  along.  But  these  slight  reservoirs  do 
not  present  any  parts  corresponding  to  the 
mammillae  and  their  infundibula  of  mam- 
malia. Below  the  kidney  the  ureters  pass  be- 
hind the  rectum,  becoming  connected  to,  and 
after  a  short  distance  involved  in  its  coats ; 
they  ultimately  terminate  upon  valvular  emi- 
nences, in  a  depression  at  the  lower  part  of  the 
urinary  sac;  the  terminal  papillse  of  the  ureters 
are  situated  with  the  orifices  of  the  genital 
ducts,  in  the  same  segment  of  the  cloaca, 
which  is  therefore  termed  the  urethro-sexual 
cavity  (e, fig.  176). 

The  space  intervening  between  the  urethro- 
sexual  cavity  and  the  valvular  termination  of 
the  rectum  (c,jig.  176)  forms  a  cavity  more  or 
less  developed  in  different  birds,  but  always 
distinct  in  the  smoothness  of  its  lining  mem- 
brane from  the  rectum,  which  has  a  more  vas- 
cular and  villous  internal  tunic.  The  birds  in 
which  this  rudimental  urinary  bladder  presents 
the  largest  capacity  are  the  Owls,  many  of  the 
aquatic  birds,  as  the  Pelecan,  Willock,  Grebe, 
Swan,  &c. ;  some  of  the  Wading  Order,  as  the 

*  Oken's  Isis,  1826,  p.  414. 


Bittern  and  Bustard,  but  more  especially  the 
Ostrich,  among  the  Cursorcs,  in  which  the 
urinary  receptacle  is  represented  as  laid  open 


Cloaca  of  the  Ostrich* 

The  Supra-renal  Glands,  Renal  capsules, 
Glandule  succenturiatts  (d,  d,  fg.  182)  are 
small  bodies,  usually  of  a  bright  yellow  colour, 
situated  on  the  mesial  or  inner  side  of  the  su- 
perior extremities  of  the  kidneys;  closely  at- 
tached to  the  coats  of  the  contiguous  large  veins 
and  in  contact  with  the  testes  in  the  male ;  and 
the  left  one  adhering  to  the  ovary  in  the  female. 
They  vary  in  shape,  being  sometimes  of  a 
round,  flattened,  oval,  or  irregularly  triangular 
figure.  They  are  proportionally  smaller  than 
in  mammalia,  being  in  the  Goose  each  about 
the  size  of  a  pea. 

They  present,  like  the  kidneys,  a  homoge- 
neous texture  throughout,  and  do  not  exhibit 
the  alternate  strata  of  different-coloured  sub- 
stances as  in  mammalia.  In  the  Gigantic  Crane 
we  found  the  texture  of  the  supra-renal  glands 
to  be  coarsely  fibrous;  in  the  Hornbill  they 
were  granular,  similar  to  the  kidney;  in  the 
Pelecan  they  were  of  a  granular  but  more 
pulpy  texture. 

There  is  no  cavity  in  the  supra-renal  glands. 
The  veins  which  return  the  blood  from  them 
are  of  proportionally  large  size,  as  in  all  the 
parenchymatous  bodies  without  excretory  ducts. 
The  supra-renal  glands  have  been  found  to 
present  a  slight  enlargement  corresponding  with 
the  increased  development  of  the  sexual  organs; 
and  it  has  been  conjectured  that  their  function 
is  related  to  that  of  the  generative  system. 

Thyroid  Glands.  In  many  birds,  as  the 
Vultures,  Falcons,  Starling,  Magpie,  Heron, 
Bustard,  and  in  most  Aquatic  birds,  two  glands 
are  found,  one  on  each  side  of  the  trachea,  very 
near  the  lower  larynx  and  frequently  attached 
to  the  jugular  veins.  They  are  regarded  as  the 
analogues  of  the  thyroid  glands.  In  addition 
to  these  there  are  two  small  glands,  in  the  Gan- 
net,  attached  to  the  upper  part  of  the  commence- 
ment of  each  bronchus. 

From  Memoircs  du  Museum,  torn.  xv.  -pi.  2,Juj.'I. 


AVES. 


349 


Peculiar  Secret  ions.—  The  unctuous  fluid 
with  which  Birds  lubricate  their  feathers  is 
secreted  by  a  gland  which  is  situated  above  the 
coccyx  or  uropygium.  This  gland  consists  of 
two  lateral  moieties  conjoined.  As  might  be 
expected,  it  is  largest  in  the  birds  svhich  frequent 
the  water.  In  the  Swan  it  is  an  inch  and  a 
half  in  length,  and  has  a  central  cavity,  which 
serves  as  a  receptacle  for  the  accumulated  secre- 
tion; but  this  cavity  has  not  been  observed  in 
other  species.  Each  lateral  portion  is  of  a 
pyriform  shape,  and  they  are  conjoined  at  the 
apices,  which  are  directed  backwards  and  are 
perforated  by  numerous  orifices.  The  longitu- 
dinal central  cavities  also  present  internally  nu- 
merous angular  openings,  in  which  there  are 
still  smaller  orifices.  The  surrounding  glandu- 
lar substance  consists  of  close-set  almost  paral- 
lel straight  tubules, and  is  not  irregularly  cellular. 
The  tubules  extend  to  the  superficies  of  the 
gland,  without  ramifying  or  intercommunicating, 
and  preserve  an  equable  diameter  to  their  blind 
extremities.  The  tubules  are  longest  at  the 
thickest  part  of  the  gland,  and  become  shorter 
and  shorter  towards  the  apex. 

Tegumentary  system. — This  is  composed,  as 
in  Mammalia  and  Reptilia,  of  the  corium  or 
derm,  epiderm,  and  its  appendages,  and  an 
intermediate  layer  of  unhardened  epiderm  with 
colouring  matter,  called  rete  mucosum. 

The  corium,  or  true  skin,  is  very  thin,  as  in 
the  cold-blooded  Ovipara.  It  adheres  io  the 
subcutaneous  muscles  by  cellular  tissue,  which 
is  frequently  the  seat  of  accumulation  of  dense 
yellow  fat ;  and  it  is  moved  by  muscles  which 
at  the  same  time  raise  and  ruffle  the  plumage 
which  it  supports. 

The  rete  mucosum  rarely  contains  any  co- 
louring matter  where  the  feathers  grow ;  at 
this  part  the  skin  is  of  a  pale,  greyish  colour, 
or  pink,  from  the  colour  of  the  blood  which 
circulates  in  it.  But  in  the  naked  parts  of 
the  integument,  as  the  cire,  the  lore,  the 
comb,  the  wattles,  the  naked  parts  of  the  head 
and  neck  in  some  birds,  and  the  tarsi  and 
toes,  the  rete  mucosum  frequently  glows  with 
the  richest  crimson,  orange,  purple,  green, 
black,  and  a  variety  of  other  tints,  of  which 
the  planches  calorics  and  the  different  zoological 
monographs  of  families  of  birds  afford  nu- 
merous examples. 

The  epidermis  is  in  some  places  continued 
as  a  simple  layer  over  the  corium,  following 
its  wrinkles  and  folds,  as  around  the  naked  necks 
of  some  Vultures.  It  is  moulded  upon  the 
bony  mandibles  to  form  the  beak,  and  in  some 
birds  adheres  to  osseous  protuberances  on  the 
cranium,  where  it  forms  a  species  of  horn ;  and 
it  is  remarkable  that  these  instances  occur  chiefly 
in  those  orders  of  birds,  the  Cursores  and 
Rasores,  which  are  most  analogous  to  the  Ru- 
minantia  among  quadrupeds:  the  Cassowary 
and  Helmeted  Curassow  are  examples.  The 
cuticle  is  sometimes  developed  into  spines  or 
spurs,  as  upon  the  wing  of  the  Secretary-bird, 

t Cassowary,  the  Apteryx,  and  the  Palamedea; 
md  upon  the  tarsi  of  the  Gallinaceous  Birds. 
The  claws  which  sheath  the  ungueal  phalanges 
>f  the  feet  assume  various  forms  adapted  to 


the  habits  and  manner  of  life  of  the  different 
orders.  A  remarkable  artificial  form  is  given 
to  the  claw  of  the  middle  toe  in  certain  birds ; 
the  inner  edge  being  produced  and  divided 
into  small  parallel  processes  like  the  close-set 
teeth  of  a  comb  (Jig.  132.)  These  teeth  are  not 
reflected  or  recurved,  as  they  might  be  expected 
to  be,  if  they  had  been  intended  to  serve  as 
holders  of  a  slippery  prey,  but  are  either  placed 
at  right  angles  to  the  claw  or  are  inclined  to- 
wards its  point.  The  Common  Barn-Owl  (Strix 
flammed),  the  Goat-sucker  genus  ( Caprimul- 
gus),  the  Heron  and  Bittern  kind  (Ardeidtg, 
Vig.),  afford  examples  of  this  structure ;  and 
as  each  species  of  bird  appears  to  be  infested 
by  its  peculiar  louse  (Nirmus),  the  solution 
of  the  final  intention  of  so  singular  a  con- 
trivance, which  is  limited  to  so  few  species, 
and  these  of  such  different  habits,  may  yet 
be  afforded  by  the  entomologist.  At  least 
it  would  be  worth  while  to  examine  the  pa- 
rasitic animals  of  the  species  so  provided,  with 
the  view  of  determining  whether  they  pos- 
sessed superior  powers  of  adhesion  which 
might  require  the  application  of  a  comb  in  the 
birds  infested  by  them.* 

With  respect  to  the  scales  'which  defend 
the  naked  parts  of  the  legs  of  birds,  they  do 
not  differ  from  those  of  Reptiles.  Their  form 
and  disposition,  as  has  been  already  observed, 
have  afforded  distinctive  characters  to  the  zoo- 
logist. In  most  of  the  Raptores,  the  Psitta- 
cidte,  the  Rasores,  the  Grallatores,  and  the 
Natatorcs,  the  scales  are  polygonal,  small, 
and  .disposed  in  a  reticulate  form  ;  the  birds 
so  characterized  formed  the  Retipedes  of  Sco- 
poli.  In  the  rest  of  the  class  the  tarsi  are 
covered  anteriorly  with  unequal  semi-annular 
scales,  ending  on  each  side  in  a  longitudinal 
furrow,  and  these  birds  were  termed  the  *  Scu- 
tipedes.'-^ 

The  four  classes  of  vertebrate  animals  have 
each  their  characteristic  external  covering :  the 
cold-blooded  Ovipara  are  naked,  or  their  ex- 
ternal surface  is  defended  only  by  hard  scales 
or  plates  ( squama  and  scuta);  but  the  warm- 
blooded classes  require  to  be  invested  by  an 
integument  better  adapted  to  maintain  the  high 
degree  of  temperature  peculiar  to  them :  hence 
quadrupeds  are  clothed  with  fur  and  hair,  and 
birds  with  down  and  feathers. 

Feathers  are  the  most  complicated  of -all 
the  modifications  of  the  epidermic  system, 
and  are  quite  peculiar  to  the  class  of  birds. 
The  eloquent  Paley  well  observes  that  "  every 

*  Mr.  Swainson  objects  to>.  the  theory  which 
ascribes  to  the  serrated  claw  the  function  of  freeing 
the  plumage  from  vermin,  because  its  presence  is 
partial  in  the  class  of  Birds.  •'  To  suppose,"  says 
he,  t(  that  nature  has  given  to  one  or  two  families 
of  birds  the  exclusive  power  of  freeing  themselves 
from  an  enemy  which  in  like  manner  infests  all 
birds,  is  preposterous."  The  assertion  that  the 
different  species  of  Nirmi  infest  all  birds  in  like 
manner  is  much  easier  than  the  proof. 

fin  one  section  of  the  Tyranni,  Cuv.  the  scutae 
surround  the  tarsi  as  complete  rings.  Where  the 
carneous  parts  of  the  muscles  are  continued  low 
down  upon  the  legs,  as  in  the  Owls,  a  covering  of 
feathers  is  co-extended  to  preserve  their  tempera- 
ture. 


350 


AVES. 


feather  is  a  mechanical  wonder;"  "  their  dis- 
position, all  inclined  backward,  the  down 
about  the  stem,  the  overlapping  of  their  tips, 
their  different  configuration  in  different  parts, 
not  to  mention  the  variety  of  their  colours, 
constitute  a  vestment  for  the  body,  so  beau- 
tiful, and  so  appropriate  to  the  life  which 
the  animal  is  to  lead,  as  that,  I  think,  we 
should  have  had  no  conception  of  any  thing 
equally  perfect,  if  we  had  never  seen  it,  or 
can  now  imagine  any  thing  more  so." 

Notwithstand- 
ing the  varieties 
of  size,  consis- 
tence,and  colour, 
all  feathers  are 
composed  of  a 
quill  or  barrel 
(a,  fig.  177),  a 
shaft  (b  b),  and 
a  vane  or  beard 
(c  c) ;  the  vane 
consists  of  barbs 
(e  e,  fig.  178) 
and  barbules  (ff, 
fig.  178). 

The  quill,  by 
which  the  feather 
is  attached  to  the 
skin,  is  larger 
and  shorter  than 
the  shaft,  is  near- 
ly cylindrical  in 
form  and  semi- 
transparent  ;  it 
possesses  in  an 
eminent  degree 
the  opposite  qua- 
lities of  strength 
and  lightness.  It 
terminates  below 
in  a  more  or  less 
obtuse  extremity, 
which  is  pierced 
by  an  orifice 
termed  the  lower 
umbilicus  (e,fig. 
177);  a  second 
orifice,  leading  into  the  interior  of  the  quill, 
is  situated  at  the  opposite  end,  at  the  point  at 
which  the  two  lateral  series  of  barbs  meet  and 
unite;  this  is  termed  the  upper  umbilicus  (f, 
fig.  \  77).  The  cavity  of  the  quill  contains  a  series 
of  conical  capsules  fitted  one  upon  the  other,  and 
united  together  by  a  central  pedicle. 

The  shaft  is  more  or  less  quadrilateral,  and 
gradually  diminishes  in  size  from  the  upper 
umbilicus  to  its  distal  extremity.  It  is  always 
slightly  bent,  and  the  concave  side  is  divided 
into  two  surfaces  by  a  middle  longitudinal 
line  continued  from  the  upper  umbilicus ;  this 
is  the  internal  surface  (c,  fig.  178).  The 
opposite,  or  external  surface  ( b,  fig.  178),  is 
smooth,  and  slightly  rounded ;  both  sides  are 
covered  with  a  horny  material  similar  to  that 

*  This  figure  and  fig.  179,  180,  181,  are  copied 
from  the  Monograph  of  F.Cuvier, "  Surle  developpe- 
ment  des  Plumes,"  Memoires  du  Museum,  torn.  xiii. 


of  which  the  quill  is  formed,  and  they  inclose 
a  peculiar  white,  soft,  elastic  substance,  called 
the /»M  (a,  fig.  178). 

Fig.  178  * 


Section  of  the  Shaft  and  Vane  magnified. 

The  barbs  are  attached  to  the  sides  of  the 
shaft  near  the  external  surface,  and  consist  of 
laminse,  varying  as  to  thickness,  breadth,  and 
length.  They  are  arranged  with  their  flat  sides 
towards  each  other,  and  their  margins  in  the 
direction  of  the  external  and  internal  sides  of 
the  feather ;  consequently  they  present  a  con- 
siderable resistance  to  being  bent  out  of  their 
plane,  although  readily  yielding  to  any  force 
acting  upon  them  in  the  line  of  the  stem  :  e  e, 
fig.  178,  are  th,e  bases  of  the  barbs  of  a 
feather  magnified.  The  barbules  (ff,  fig. 
178)  are  given  off  from  either  side  of  the  barbs, 
and  are  sometimes  similarly  barbed  themselves, 
as  may  be  seen  in  the  barbules  of  the  great 
feathers  of  the  Peacock's  tail. 

Sometimes,  as  in  these  feathers  and  in  the 
plumes  of  the  Ostrich,  the  barbules  are  long 
and  loose ;  but  more  commonly  they  are  short 
and  close-set,  and  by  their  form  and  disposition 
constitute  the  mechanism  by  which  the  barbs 
are  united  together.  The  barbules  arising  from 
the  upper  side  of  the  barb,  or  that  next  the 
extremity  of  the  feather,  are  curved  downwards 
or  towards  the  internal  surface  of  the  shaft ; 
those  which  arise  from  the  under  side  of  the 
barb  are  curved  in  the  contrary  direction :  so  that 
the  two  adjoining  series  of  hooked  barbules  lock 
into  one  another  in  a  manner  which  the  Pari- 
sian dissectors  compare  to  the  fastening  of  a 
latch  of  a  door  into  the  catch  of  the  door-post. 

But  besides  the  parts  which  constitute  the 
perfect  feather,  there  is  also  an  appendage 
attached  to  the  upper  umbilicus  of  the  quill 
which  requires  to  be  noticed.  This  is  termed 
the  accessory  plume.  It  is  usually  a  small 
downy  tuft,  but  varies  both  in  different  species, 
and  even  in  the  feathers  of  different  parts  of 
the  body  of  the  same  bird.  In  the  quill- 
feathers  of  the  wings  and  tail,  it  usually 
remains  in  the  rudimentary  state  of  a  small 
tuft  of  down;  but  in  the  body-feathers  of 
Hawks,  Grouse,  Ducks,  Gulls,  &c.  it  is  to 
be  found  of  all  sizes,  acquiring  in  some  species 
a  size  equal  to  that  of  the  feather  from  which 
it  is  produced. 

*  Perrault,  Hist.  Nat.  des  Animaux,  p.  336. 


AVES. 


351 


In  the  Ostrich  the  feathers  have  no  accessory 
plume :  in  the  Rhea  it  is  represented  by  a  tuft 
of  down ;  in  the  Emeu,  on  the  contrary,  the 
accessory  plume  equals  the  original  feather,  so 
that  the  quill  supports  two  shafts ;  and  in  the 
Cassowary,  besides  the  double  feather,  there 
is  also  a  second  accessory  plume,  so  that 
the  quill  supports  three  distinct  shafts  and 
vanes. 

The  feathers  vary  in  form  in  different  parts 
of  the  bird  according  to  their  functions,  and 
afford  zoological  characters  for  the  distinction 
of  species;  they  have,  therefore,  received  in 
Ornithology  distinct  names.  Those  which 
surround  or  cover  the  external  opening  of  the 
ear  are  termed  '  auriculars.'  Those  which 
lie  above  the  scapula  and  hurnerus  are 
called  the  *  scapulars.'  The  small  feathers 
which  lie  in  several  rows  upon  the  bones  of 
the  antibrachium  are  called  the  *  lesser  coverts ' 
(tectrices  prinue).  Those  which  line  the  under 
or  inner  side  of  the  wings  are  the  '  under 
coverts.'  The  feathers  which  lie  immediately 
over  the  quill-feathers  are  the  '  greater  coverts ' 
(tectrices  secunda).  The  largest  quill-feathers 
of  the  wing,  which  arise  from  the  bones  of 
the  hand,  are  termed  '  primaries'  (primores). 
Those  which  rise  from  the  ulna,  towards  its 
distal  end,  are  the  '  secondaries'  (secondaria). 
Those  which  are  attached  to  its  proximal  ex- 
tremity are  the  '  tertiaries'  (tertiaria).  These 
in  some  birds,  as  the  Woodcock  and  Snipe, 
are  so  long  as  to  give  them  the  appearance, 
when  flying,  of  having  four  wings.  The 
quill-feathers  which  grow  from  the  phalanx, 
representing  the  thumb,  form  what  is  termed 
the  bastard  wing  ( alula  spuria). 

In  considering  the  structures  which  deter- 
mine the  powers  of  flight  in  different  birds, 
it  is  necessary  to  take  into  account  the  structure, 
forms,  and  proportions  of  the  wing-feathers, 
as  well  as  the  development  of  the  bones  and 
muscles  which  support  and  move  them;  as 
much  depends  upon  the  mechanical  advantages 
resulting  from  the  shape  and  texture  of  the 
expanded  wing.  When  the  primary  quill- 
feathers  gradually  increase  in  length  as  they 
are  situated  nearer  the  extremity  of  the  pinion, 
they  give  rise  to  the  acuminated  form  of  wing, 
as  in  the  true  Falcons,  in  which  the  second 
primary  is  the  longest.  In  the  Hawks  the 
wing  is  of  a  less  advantageous  form,  in  con- 
sequence of  the  fourth  primary  being  the 
longest ;  when  the  primaries  gradually  decrease 
in  length  towards  the  end  of  the  pinion,  they 
give  rise  to  a  short  rounded  form  of  wing, 
such  as  characterizes  the  Gallinaceous  Order; 
in  which,  although  the  pectoral  muscles  are 
immensely  developed  in  order  to  counteract 
the  disadvantage  resulting  from  the  disposition 
of  the  primaries,  yet  they  are  only  able,  in 
consequence  of  the  form  of  the  wing,  to  carry 
the  bird  rapidly  forward  for  a  short  distance, 
and  that  with  an  exertion  and  vibratory  noise 
well  known  to  every  spoilsman. 

The  texture  of  the  quill-feathers  has  also  a 
material  effect  on  the  powers  of  flight.  In 
the  Falcons  each  primary  quill-feather  is 
elongated,  narrow,  and  gradually  tapers  to  a 
point;  the  webs  are  entire,  and  the  barbs 


Fig.  179. 


closely  and  firmly  connected  together.*  In 
the  Owls  the  plumage  is  loose  and  soft,  and 
the  outer  edge  of  the  primaries  is  serrated  ; 
so  that,  while  they  are  debarred  from  a  rapid 
flight,  which  would  be  dangerous  in  the  gloom 
in  which  they  go  abroad,  they  are  enabled,  by 
the  same  mechanism,  to  wing  their  way  without 
noise,  and  steal  unheard  upon  their  prey. 

Development  of  feathers. — The  first  covering 
of  the  bird  is  a  partial  and  temporary  one, 
consisting  of  fasciculi  of  long  filaments  of 
down,  which  on  their  first  appearance  are  en- 
veloped in  a  thin  sheath,  but  this  soon  crumbles 
away  after  being  exposed  to  the  atmosphere. 
The  down-fasciculi,  which  diverge  each  from 
a  small  quill,  are  succeeded  by  the  fea- 
thers, which  they  guide,  as  it  were,  through 
the  skin :  and  after  the  first  plumage,  at  each 
succeeding  moult,  the  old  feathers  serve  as 
the  gubernacula  to  those  which  are  to  follow. 
It  is  to  be  observed  that  feathers  do  not  grow 
equally  from  every  part  of  a  surface  of  a  bird ; 
they  are  not  developed,  for  example,  at  those 
parts  which  are  subject  to  friction  from  the 
movements  of  the  wings  and  legs.  They 
first  appear  in  clumps  upon  those  parts  of  the 
skin  which  is  least  affected  by  the  pressure  of 
superincumbent  parts,  or  the  movement  of  the 
parts  beneath,  as  upon  the  head,  along  the 
spine,  upon  the  exterior  surface  of  the  extre- 
mities, at  the  intervals  of  the  joints  on  either 
side  the  projecting  sternum,  and  at  the  sides 
of  the  abdomen. 

The  matrix,  or  organ  by 
which  the  perfect  feather  is 
produced,  has  the  form  of  an 
elongated  cylindrical  cone, 
and  consists  of  a  capsule,  a 
bulb,  and  intermediate  mem- 
branes which  mould  the  secre- 
tion of  the  bulb  into  its  ap- 
propriate form.  The  matrix 
is  at  first  an  extremely  minute 
cone,  attached  by  a  filamen- 
tary process  to  a  follicle  or 
papilla  of  the  skin ;  but  it  is 
not  a  development  of  that 
part,  being  of  a  different 
structure  and  adhering  to  it 
by  a  small  part  only  of  ts 
circumference.  The  matrix 
progressively  increases  in 
length ;  its  base  sinking  deep- 
ly into  the  corium,  and  ac- 
quiring a  more  extended  con- 
nection by  enlarged  vessels 
and  nerves,  while  its  apex 
protrudes  to  a  greater  or  less 
extent  from  the  surface  of  the 
integument,  when  the  cap- 
sule  drops  off  to  give  passage  MaMg  of  a 
to  the  feather  which  it  incloses,  ing  Feather,  with 
and  the  formation  of  which  the  Capsule  laid 
has,  in  the  meanwhile,  been  open. 

*  Of  so  much  consequence  are  the  quill-feathers 
to  the  Falcons,  that  when  any  of  them  are  broken 
the  flight  is  injured  and  the  falconers  find  it  ne- 
cessary to  repair  them  ;  for  this  purpose  they  are 
always  provided  with  perfect  pinion  and  tail  fea- 
thers, regularly  numbered. 


352 


AVES. 


graduallyproceeding  from  the  apex  downwards. 
The  capsule  of  the  matrix  (a  a,  Jig.  179)  is 
composed  of  several  layers,  the  outermost  of 
which  is  of  the  nature  of  epidermis ;  the  inner 
ones  are  more  compact,  but  have  no  appear- 
ance of  organization.  The  sides  of  the  cap- 
sule which  correspond  to  the  outer  and  inner 
sides  of  the  growing  feather  within  are  indi- 
cated by  a  white  longitudinal  line. 

The  axis  of  the  capsule  is  occupied  by  a 
medulla  or  bulb,  (e,  fig.  179,)  also  of  a  cy- 
lindrical form,  and  of  a  soft  fibrous  texture, 
adhering  by  its  base  to  the  parts  beneath,  and 
there  receiving  numerous  bloodvessels  and  a 
nerve. 

Between  the  medulla  and  the  capsule 
there  are  two  parallel  membranes,  one  in- 
ternal (dj  fig.  179);  the  other  external, 
(b,  fig.  179);  from  the  latter  membrane  a 
number  of  close-set  parallel  laminae  extend 
obliquely  from  one  of  the  white  longitudinal 
lines  above  mentioned  to  the  other  on  the 
opposite  side  of  the  cylinder.  The  two  mem- 
branes seem  to  be  united  together  by  the 
oblique  septa.  In  the  long  and  narrow  spaces 
between  these  septae,  the  matter  of  the  vane 
(c.  Jig.  179)  is  deposited,  and  formed  into 
barbs  and  barbules,  nearly  in  the  same  way  as 
the  enamel  of  the  teeth  is  formed  between  the 
external  membrane  of  the  pulp,  and  the  in- 
ternal membrane  of  the  capsule.  The  depo- 
sition of  the  material  of  the  barbs  commences 
at  the  apex  of  the  bulb,  and  the  stem  is  next 
formed  in  the  following  manner, 

The  external  longitudinal  line  fron>  which 
the  oblique  laminae  are  continued,  receives  and 
moulds  on  the  inner  surface  of  the  external 
capsule  the  horny  covering  of  the  back  of  the 
feather,  or  that  longitudinal  band,  to  the  two 
sides  of  which  the  barbs  are  attached  ;  and  on 
the  opposite  surface  of  the  internal  membrane 
are  formed  the  pith  or  substance  of  the  shaft1, 
and  the  horny  pellicle  which  incloses  it  on  the 
inner  surface.  The  internal  longitudinal  line 
has  no  other  use  than  to  establish  a  solution 
of  continuity  between  the  extremities  of  the 
barbs  of  one  side  and  those  of  the  other,  which 
meet  at  that  part,  and  thus  curve  round  and 
completely  inclose  the  formative  bulb.  In 
fig.  180,  the  capsule  of  the  matrix  of  a  grow- 
ing feather  has  been  laid  open,  and  the  nascent 
barbs  (c)  which  surrounded  the  bulb  have  been 
unfolded,  exposing  that  part  at  a  b.  A  portion 
of  the  barbs  and  stem  have  been  completed 
and  protruded,  and  the  bulb  is  beginning  to 
undergo  a  process  of  absorption  at  that  part, 
which  will  hereafter  be  described.  The  shaft 
and  barbs  at  the  apex  of  the  cylinder  are  the 
first  parts  which  acquire  consistence,  and  the 
molecules  composing  the  remainder  are  less 
compactly  aggregated  as  they  are  situated 
nearer  the  base  of  the  matrix.  As  the  gela- 
tinous medulla  increases,  at  the  base,  the  first- 
formed  shaft  and  barbs  are  protruded  through 
the  extremity  of  the  capsule,  the  bulb  con- 
tinuing to  furnish  the  secretion  which  is  moulded 
between  the  two  striated  membranes  until  the 
entire  feather  is  completed.  If  the  striated 
membrane  inclosing  the  bulb  be  attempted  to 


Fig.  180. 


Structure  of  the  Bulb. 

be  reflected  from  below  upwards,  it  will  be 
found  to  be  connected  with  a  series  of  mem- 
branous cones  (abed  e,fig.  181,)  ranged  one 
upon  the  other  throughout  the  whole  length  of 
the  bulb,  and  connected  together  by  a  tube 
running  through  its  centre.  In  this  figure 
(181)  the  pulpy  matter  which  occupied  the 
interspaces  of  the  cones  has  been  removed  to 
shew  their  central  connecting  tube. 

As  the  development  of  the  feather  advances, 
the  pulpy  matter  disappears  from  the  summit 
of  the  medulla,  and  only  the  membranous 
funnel-shaped  caps  remain,  which  are  pro- 
truded from  the  theca  and  ithe  centre  of  the 
new-formed  barbs,  and  fall  off.  as  these  ex- 
pand. The  theca  which  incloses  the  whole 
is  of  a  firm  texture  where  the  new  moulded 
barbs  are  yet  pulpy  and  tender,  but  it  be- 
comes thinner  as  these  acquire  consistency, 
and  lastly,  dries  and  crumbles  away  after  it 
has  been  exposed  to  the  action  of  the  atmos- 
phere. The  bulb  itself,  when  examined  in  a 
half-formed  quill-feather,*  is  composed  of  two 
parts  corresponding  to  the  external  and  in- 
ternal aspects  of  the  feather.  The  internal 
part  represents  a  semi-cylinder  or  case,  in- 

*  The  following  description  is  taken  from  such  a 
feather  in  the  goose. 


AVES. 


3J3 


closing  the  external  part,  which  is  of  a  conical 
form  ;  the  latter  extends  from  the  base  of  the 
bulb,  and  gradually  diminishes  to  a  point 
where  the  shaft  is  completed  and  the  barbs 
begin  to  expand.  Jts  office  is  to  deposit  the 
pith  within  the  shaft,  and  it  is  absorbed  in 
proportion  as  this  is  effected.  The  internal 
part  or  case  also  commences  at  the  base  of  the 
bull),  and  adheres  closely  to  the  cone,  with 
which,  indeed,  its  substance  is  continuous;  it 
increases  in  thickness  as  the  cone  diminishes, 
its  margins  are  beautifully  scolloped  or  crenate, 
and  the  crenations  are  lodged  in  the  interspaces 
of  the  oblique  laminae  or  moulds,  and  deposit 
in  them  the  material  of  the  vane.  The  horny 
sides  of  the  shaft  are  lodged  and  formed  in  the 
grooves  between  the  external  and  internal  parts 
of  the  bulb,  and  correspond  in  degree  of 
formation  to  the  depths  of  those  grooves,  and 
being  progressively  brought  into  contact  from 
above  downwards,  the  shaft  is  thus  completed, 
leaving  the  longitudinal  line  at  the  internal 
side.  When  all  the  grooves,  (wherein  are 
formed  the  barbs,  and  the  portion  of  the  shaft 
which  carries  them)  are  filled  by  the  horny 
matter,  and  the  barbed  part  of  the  feather  is 
finished,  this  horny  matter  lastly  expands  uni- 
formly around  the  medulla,  and  forms  the  quill 
of  the  feather. 

When  the  quill  of  the  feather  has  acquired 
the  due  consistence,  the  internal  medulla  be- 
comes dried  up,  and  is  resolved,  as  before,  into 
membranous  cones  arranged  one  upon  the 
other ;  but  these  latter  never  pass  out,  for  the 
quill,  which  is  now  hardened  and  closed  by 
the  shaft  at  the  opposite  extremity  to  the  lower 
umbilicus,  will  not  permit  their  egress  ;  they 
remain,  therefore,  inclosed,  and  constitute  the 
light  dry  pith  which  is  found  in  the  interior  of 
the  quill.  The  last  remains  of  the  bulb  are  seen 
in  the  ligament  which  passes  from  the  pith 
through  the  lower  opening  of  the  quill  and 
attaches  it  to  the  skin. 

Cuvier  has  justly  observed  that  notwith- 
standing the  complexity  of  the  process  just  de- 
scribed, the  formation  of  a  feather  differs  only 
from  that  of  a  tooth  in  the  nature  of  the  substance 
which  is  deposited  between  the  two  tunics 
which  constitute  its  mould  ;  but  a  tooth  takes 
many  years  to  be  perfected,  and  there  are  but 
two  series  produced  in  one  part  of  the  jaw,  and 
only  oi:e  in  the  other,  in  any  warm-blooded 
animal.  Feathers,  on  the  other  hand,  are  de- 
veloped in  the  course  of  some  days ;  they 
attain  a  length  of  from  one  to  two  feet  or  more 
in  many  birds,  and  they  are  almost  all  re- 
newed every  year, — in  many  species  even  twice 
a  year.  It  may  be  conceived,  then,  how  much 
vital  energy  the  organization  of  birds  must 
exercise,  and  how  many  dangers  must  accom- 
pany so  critical  a  period  as  that  of  the  moult. 

The  plumage  is  commonly  changed  several 
times  before  it  attains  that  state  which  is  re- 
garded as  characteristic  of  the  adult  bird. 
The  time  required  for  this  varies  from  one  to 
five  years,  and  several  birds  rear  a  progeny 
before  they  acquire  the  plumage  of  maturity. 

When  the  male  bird  assumes  a  vestment 
VOL.  i. 


differing  in  colour  from  the  female,  the  young 
birds  of  both  sexes  resemble  the  latter  in  their 
first  plumage  ;  but  when  the  adult  male  and 
female  are  of  the  same  colour,  the  young  have 
then  a  plumage  peculiar  to  themselves.  Mr. 
Yarrell  states  a  third  law  in  addition  to  the 
preceding,  viz.  that  whenever  adult  birds  as- 
sume a  plumage  during  the  breeding  season 
decidedly  different  in  colour  from  that  which 
they  bear  in  winter,  the  young  birds  have  a 
plumage  intermediate  in  the  general  tone  of  its 
colour  compared  with  the  two  periodical  states 
of  the  parent  birds,  and  bearing  also  indica- 
tions of  the  colours  to  be  afterwards  attained 
at  either  period. 

"  There  are  three  modes,"  the  same  author 
observes, "  by  which  changes  in  the  appearance 
of  the  plumage  of  birds  are  produced  : — 

"  By  the  feather  itself  becoming  altered  in 
colour. 

"  By  the  bird's  obtaining  a  certain  number 
of  new  feathers  without  shedding  any  of  the 
old  ones  ;  and 

"  By  an  entire  or  partial  moulting,  at  which 
old  feathers  are  thrown  off  and  new  ones  pro- 
duced in  their  places. 

"  The  first  two  of  these  changes  are  ob- 
served in  adult  birds  at  the  end  of  spring,  in- 
dicating the  approach  of  the  breeding  season  ; 
the  third  change  is  partial  in  spring  and  entire 
in  autumn. 

"  A  fourth  mode  may  be  noticed,  though 
its  effects  are  limited.  It  is  observable  in 
spring,  as  the  breeding  season  approaches,  by 
the  wearing  off  of  the  lengthened  lighter- 
coloured  tips  of  the  barbs  of  the  feathers  on 
the  body,  by  which  the  brighter  tints  of  the 
plumage  underneath  are  exposed,  as  was  no- 
ticed by  Sir  William  Jardine  and  Mr.  Blyth. 
The  effect  is  most  conspicuous  in  the  Buntings, 
Finches,  and  Warblers."* 

The  experiments  detailed  in  the  Memoir 
above  quoted,  some  of  which  we  witnessed, 
prove  incontestably,  that  notwithstanding  the 
extravascular  nature  of  feathers,  they  are 
subject  to  influences,  apparently  of  a  vital 
nature,  which  occasion  a  change  of  colour  in 
them  after  they  are  completely  formed.  In 
yearling  birds  the  winter  plumage  which  suc- 
ceeds the  autumnal  moult  gradually  assumes 
the  brighter  tints  characteristic  of  the  adult 
without  a  change  of  feather.  The  new  colour 
commences  generally  at  that  part  of  the  web 
nearest  the  body  of  the  bird,  and  gradually 
extends  outwards  till  it  pervades  the  whole 
feather. 

Organs  of  generation.  —  The  few  varieties 
of  structure  which  these  organs  present  in  the 
Class  of  Birds,  are  principally  met  with  in 
those  of  the  male,  which  we  shall  first  de- 
scribe. 

The  male  organs  of  generation  exhibit  all 
the  essential  characteristics  of  the  oviparous 
type  of  structure.  The  testes  are  situated  high 
up  in  the  abdomen,  whence  they  never  descend 
into  an  external  scrotum.  The  intromittent 

*   Yarrell,  Zool.  Trans,  i.  p.  13. 
2  A 


354 


AVES. 


organ  is  either  double,  as  in  Serpents,  when, 
however,  each  penis  is  extremely  small ;  or  it 
is  single,  but  in  this  case,  to  whatever  extent 
it  may  be  developed,  it  always  consists  of  a 
uniform  ligamentous  and  vascular  elastic  sub- 
stance, and,  as  in  the  Tortoise,  is  simply 
grooved  along  the  upper  surface  or  dorsum  for 
the  passage  of  the  fecundating  fluid. 

As  there  is  no  true  urethral  canal,  so  neither 
are  the  glands  of  Cowper  or  the  prostatic 
glands  present. 

The  testes  (x,  Jig.  166, 
tf>  a>fg'  182)  nre  two  in 
number;  in  form  more  or 
less  oval,  situated  above 
the  upper  extremities  of 
the  kidneys.  They  vary 
remarkably  in  colour  in 
different  birds;  we  may 
mention,  as  examples, 
that  they  are  white  in 
the  Peregrine  Falcon  and 
and  Dove ;  pale  yellow 
in  the  Horn-Owl,  and  19~ 
Gallinule ;  of  a  brighter 
yellow  in  the  Magpie, 
Bay  Ibis,  Ruff,  and  Oys- 
ter-catcher; of  a  black 
colour  in  the  Chough, 
Partridge,  Heron,  Sea- 
gull, but  whitish  towards 
the  lower  end  in  the  last  9 
two.  They  are  invested 
with  a  strong  and  dense 
albuginean  tunic.  Their 
structure  is  evidently  tu- 
bular, the  contorted  tu- 
bules are  very  slender, 
scarcely  exceeding  in  di- 
ameter the  seminal  tu-  Urinary  and  male  organs 
bules  of  mammalia :  they  °f  a  Cocft- 

are  separated  into  packets  by  delicate  and  mem- 
branous septa,  continued  from  the  inner  surface 
of  the  tunica  albuginea. 

The  arteries  spread  in  an  arborescent  form 
beneath  that  capsule.  The  vas  deferens  (c  c) 
is  continued  from  the  posterior  and  internal 
part  of  the  gland. 

The  periodical  variations  of  size  which  the 
testicles  undergo  are  very  remarkable  in  the 
Class  of  Birds;  and  the  limited  period  during 
which  their  function  is  in  activity  is  compen- 
sated by  the  frequency  and  energy  with  which 
it  is  exercised. 

The  proportional  size  which  the  testes  ac- 
quire at  the  breeding  season  is  immense,  as  may 
be  seen  in  the  subjoined  figures  (183)  of  the 
testes  of  the  House-Sparrow;*  which  commences 
with  the  glands  as  they  appear  in  January, 
when  they  are  no  bigger  than  pins'  heads,  and 
ends  with  their  full  development  in  April. 

It  rarely  happens  that  both  testes  are  deve- 
loped in  exactly  the  same  degree,  but  the 
increase  of  size  is  not  limited  to  the  one  on 
the  left  side.  The  right  testis  is  as  often  the 

*  See  John   Hunter,  in  the  Animal  (Economy, 
plate  vii. 


Fig.  183. 
O 

1.  January. 

0 

^  2.  Middle  of  February. 

o 

3.  Beginning  of  March. 


4.  Latter  end  of  March. 


Middle  of  April. 


Testes  of  the  House-Sparrow. 

largest,  and  we  have  seen  an  example,  in  a 
Rook,  where  it  alone  had  taken  on  the  action 
of  sexual  increase,  and  had  acquired  a  bulk 
compensating  for  the  want  of  development  in 
the  left  testis. 

In  most  Birds,  the  only  appearance  of  an 
epididymis  is  a  remnant  of  the  Wolffian  body 
or  primordial  matrix  of  the  genital  and  urinary 
organs  (6,  Jig.  182).  This  part  frequently  pre- 
sents a  co!6ur  strikingly  different  from  that 
of  the  testes:  thus  it  has  been  observed  in 
the  Bustard  and  Curassow  to  be  black ;  in  the 
Cassowary,  yellow ;  and  in  the  Anthropoides 
Virgo  to  be  of  a  green  colour. 

In  the  Ostrich  the  epididymis  is  folded  upon 
itself  at  the  side  of  the  testis. 

The  vas  deferens  commonly  passes  down 
to  the  cloaca  by  the  side  of  the  ureters 
without  undergoing  any  remarkable  convo- 
lution;  but  in  the  common  Cock  it  is  bent 
upon  itself  in  short  transverse  folds  from  side 
to  side  almost  from  its  commencement;  the 
folds  gradually  but  slightly  increase  as  they 
approach  the  cloaca,  both  in  extent  and  in  the 
diameter  of  the  tube  composing  them,  and 
they  are  so  closely  compacted  as  to  present  in 
a  longitudinal  section  the  appearance  of  a 
series  of  cells,  which  are  capable  of  retaining, 
as  in  a  vesicula  seminalis,  a  quantity  of  the 
seminal  secretion. 

Each  vas  deferens  in  the  Common  Cock 
terminates  on  a  separate  rudimentary  penis  or 
papilla,  situated  in  the  urethro-sexual  division 
of  the  cloaca  at  a  little  distance  from  each 
other,  and  anterior  to,  or  sternad  of  the  inser- 
tions of  the  ureters. 

The  base  of  each  papilla  is  surrounded  by  a 
remarkable  plexus  of  arteries  and  veins  (M,  M, 
Jig.  171)  which  serve  as  an  erectile  organ  during 
the  venereal  orgasm,  when  the  turgid  papillae  are 


AVES. 


everted,  and  the  semen  brought  into  contact  with 
the  similarly  everted  orifice  of  the  oviduct  in  the 
female,  along  which  the  fecundating  fluid  is 
impelled  by  the  vibrations  of  the  cilia  of  the 
mucous  surface  through  all  the  windings  of 
that  tube  to  its  ultimate  destination. 

In  the  Natatores  which  copulate  in  water 
there  is  an  obvious  necessity  for  a  more  effici- 
ent coitus  than  a  simple  contact  of  everted 
cloacae,  and  consequently  in  these  birds,  as  the 
Swan,  Gander,  Drake,  &c.  a  long,  single  penis 
is  developed. 

Fig.  184. 


Penis  of  a  Drake. 

This  body  arises  from  the  front  part  of  the 
outer  compartment  of  the  cloaca  ( (t,  a,  Jig.  184) 
immediately  below  the  urethro-sexual  cavity ; 


it  is  in  the  unexcited  state  coiled  up  lik^  a 
screw  from  the  elasticity  of  the  internal  liga- 
mentous  structure.  The  external  coat  is  a  pro- 
duction of  the  membrane  lining  the  outer 
cavity,  and  gives  oft' a  number  of  small  pointed 
processes,  which  in  the  Gander  are  arranged  in 
transverse  rows  on  either  side  the  urethral 
groove,  and  near  the  extremity  of  the  penis  are 
inclined  backwards.  The  body  (b  6,  fig.  184, 
where  it  has  been  cut  open)  is  composed  of  a 
white  elastic  ligamentous  substance,  and  a 
vascular  pulp,  but  without  any  of  the  cellular 
structure  which  characterizes  a  corpus  caver- 
nosum.  A  groove  (d  d),  commencing  widely 
at  the  base  is  continued  along  the  side  of  the 
ligamentous  substance,  and  follows  all  the 
spiral  turns  of  the  penis  to  its  extremity. 
The  vasa  deferentia  terminate  in  papilloe  at 
the  base  of  this  groove,  along  which  the  semen 
is  transmitted  to  the  vagina  of  the  female.* 

The  penis  of  the  Ostrich  is  also  single,  and 
the  urethra  is  represented  by  a  dorsal  groove ; 
it  is  disposed  in  a  slight  spiral  bend  when  in  a 
retracted  state.  It  arises  by  two  strong  liga- 
mentous crura  from  the  cartilage  uniting  the 
bones  of  the  pubis,  and  descends  into  the 
external  or  preputial  compartment  of  the 
cloaca.  There  are  four  muscles  to  the  penis 
of  the  Ostrich :  two  arise  from  the  inside  of  the 
os  sacrum,  and  descending  along  the  preputial 
cavity,  are  inserted  into  the  base  of  the  penis : 
two  other  muscles  pass  from  the  internal  part 
of  the  iliac  bones,  to  be  attached  to  the  sides 
of  the  penis. 

The  Guan  (Penelope  cristata)  presents  a 
singular  exception  to  the  other  Rasorial  Birds 
in  having  a  single  linguiform  pointed  penis 
developed,  the  sides  of  which  are  provided 
with  retroverted  papillae,  as  in  the  Anserine 
Birds.  In  the  Gallinule,  which  seeks  its  food 
in  water,  there  is  no  penis  ;  it,  therefore,  most 
probably  copulates  on  land. 

The  tumid  margin  of  the  preputial  cavity 
of  the  penis  is  well  provided  with  large  mu- 
cous follicles  which  secrete  a  sebaceous  lubri- 
cating substance ;  of  these  there  are  twelve  in 
the  Gander,  arranged  six  on  each  side.  These 
may  be  regarded  as  analogous  to  the  glandule 
odorifera? ;  but  there  is  no  vestige  either  of 
prostatic  or  other  urethral  glands. 

Female  organs  of  generation. — An  ovarium 
or  productive  organ,  (a,  6,  c,  d,  Jig.  185,)  with 
an  oviduct  or  efferent  tube  ( e,  f,  g,  k,  /,)  are 
present  in  all  birds,  and  a  clitoris  or  organ  of 

*  We  cannot  account  for  the  error  into  which 
Sir  Everard  Home  has  fallen,  in  describing  the 
urethra  of  the  drake  as  a  complete  canal,  and  the 
penis  as  being  enclosed  within  a  prepuce.  (Phil. 
Trans.  1802,  pp.  361,  363.)  Repeated  dissections 
of  different  species  of  Anas,  Cuv.  have  satisfied 
us  of  the  accuracy  of  Mr.  Hunter's  statement, 
that  "  birds  have  no  urethra,  some  having  merely 
a  groove,  as  the  Drake  and  Gander,  and  many 
being  even  without  a  groove,  as  the  common  Fowl." 
Animal  (Economy,  p.  40.  The  letter  c,  in  Sir 
Everard  Home's  figure,  (jig.  184,)  points  to  the 
orifices  of  mucous  glands  or  cut  vessels,  and  not  to 
the  papilla?,  on  which  the  vasa  deferentia  termi- 
nate. 

2   A   2 


356 


AVES. 


Fig.  185. 


-d 


FowIS 

excitement  is  found  in  those  species  of  which 
the  males  have  a  penis. 

Birds  differ  from  all  the  other  oviparous 
vertebrata  in  having  the  canal  which  completes 
and  carries  out  the  ovum  single,  and  in  this 
respect  they  manifest  an  analogy  to  many 
mammalia.  When,  however,  the  whole  of  the 
circumstances  from  which  this  condition  re- 
sults come  to  be  investigated,  the  nature  of  the 
part  in  the  two  classes  will  be  found  to  be 
widely  different. 

In  the  Mammalia  the  single  efferent  canal 
results  from  a  blending  together  of  the  vaginas 
and  uteri  of  the  two  sides  of  the  body  for  a 
greater  or  less  extent  along  the  mesial  line; 
which  junction  is  continued  from  the  external 
outlet  towards  the  ovaria,  but  never  extends 
beyond  the  uteri,  the  Fallopian  tubes  always 
remaining  distinct.  And  in  proportion  as  the 
generation  approximates  the  oviparous  mode, 
the  efferent  tubes  remain  separate  for  a  greater 
extent.  Thus,  among  the  Kodentia,  we  find 
the  uterus  completely  divided  into  two  lateral 
tubes,  as  in  the  Rabbit;  and  in  the  Marsupiata 
the  division  is  continued  through  the  whole 
extent  of  the  true  vagina. 

In  the  true  Oviparous  classes  the  oviducts 
are  always  double  and  open  separately  into  the 
cloaca,  and  the  exception  in  the  class  of  Birds 
to  this  rule  is  only  apparent. 

At  an  early  period  of  existence  the  two 
oviducts  exist  of  equal  size,  but  the  left  one 
alone  attains  that  state  of  development  which 
qualifies  it  for  the  exercise  of  the  sexual  func- 
tions. Hitherto  no  exception  has  been  found 

*  This  figure,  and  those  numbered  133,  134,  135, 
136,  138,  151,  153,  163,  182,  are  copied  from  the 
plates  of  the  second  edition  of  Carus's  '  Verglei- 
chenden  Zootomie.' 


to  this  rule,  and  the  uniformity  in  the  condition 
of  the  excluded  ovum  in  Birds  corresponds  with 
the  sameness  which  prevails  in  the  structure  of 
the  organs  concerned  in  its  evolution. 

The  ovarium  is  in  general  single  like  the 
oviduct,  and  developed  only  on  the  left  side, 
as  in  the  Rasores.  But  two  ovaria  have  been 
observed  in  many  of  the  Raptores.  In  the 
Falcons  NITZSCH  found  the  right  ovary  more 
developed  than  the  left,  and  also  m  some 
species  of  Eagle  and  Owl.  In  the  Sparrow- 
Hawk  the  same  distinguished  anatomist  found 
two  ovaries  equally  well  developed. 

In  the  Common  Fowl  the  ovary  first  makes 
its  appearance  as  a  membrane  beset  with  small 
pellucid  vesicles  adhering  to  and  apparently 
developed  from  the  coats  of  the  vena  cava. 
The  substance  of  the  ovary  is  invested  by  a 
thin  and  extensible  capsula  propria,  covered 
by  a  reflection  of  peritoneum.  The  ova  are 
imbedded  in  a  stroma  of  delicate  and  yielding 
cellular  substance,  and  consist  each  of  a  mi- 
nute pellucid  vesicle,  surrounded  by  the  yolk, 
which  at  this  period  is  as  clear  as  the  fluid  of 
the  vesicle  itself,  and  both  are  inclosed  in  a 
distinct  transparent  capsule. 

When  the  ovum  has  attained  the  diameter 
of  a  line,  the  vitelline  liquid  presents  a  turbid 
whitish  appearance.  When  it  is  about  the  size 
of  a  pea  the  yolk  begins  to  assume  a  slight 
straw-coloured  tint,  and  the  seat  of  this  colour- 
ing matter  may  be  observed  to  be  certain  glo- 
bules of  oil  now  superadded  to  the  albuminous 
and  serous  fluid.  As  the  oily  material  prevails, 
the  yolk  gradually  assumes  a  more  viscid  and 
tenaceous  consistency,  and  a  deeper  and  deeper 
tint,  until  it  presents  the  rich  orange  colour 
characteristic  of  the  mature  ovarian  ovum. 

If  one  of  these  ova  be  transversely  divided 
after  being  hard-boiled,  the  cut  surfaces  of  the 
yolk  will  present  three  concentric  strata  of  diffe- 
rent colours ;  the  external  one  is  of  a  pale  straw 
colour,  the  middle  one  of  a  deeper  yellow, 
and  the  internal  one  is  again  light-coloured, 
and  surrounds  a  substance  of  a  whitish  colour 
and  more  fluid  consistency,  from  which  a  canal 
surrounded  by  a  similar  substance  is  continued 
to  the  cicatricula.  The  central  substance  and 
continuous  canal  are  composed  of  albuminous 
fluid  containing  white  granules,  similar  to  the 
colliquamentum  of  the  cicatricula. 

The  primitive  vesicle  of  the  ovum  around 
which  the  material  of  the  yolk  is  accumulated, 
by  no  means  grows  with  the  growth  of  the 
ovum ;  it  is  not  more  than  one-half  larger  in 
the  largest  ovarian  ovum,  than  it  was  when 
the  ovum  exhibited  its  smallest  dimensions, 
and  when  the  vesicle  formed  its  most  con- 
siderable part.  Throughout  the  whole  of  this 
period  it  is,  however,  the  most  important  part 
of  the  ovarian  ovum;  forming  the  essential 
element  of  the  cicatricula,  and  the  centre  from 
which  all  subsequent  development  radiates. 

Purkinge,  the  discoverer  of  the  '  germinative 
vesicle,'  states  that  it  is  most  easily  detected 
in  the  ova  of  the  common  Fowl,  when  they 
have  attained  the  size  of  from  four  to  six  lines. 
The  vesicle  is  at  this  period  lodged  in  a  mam- 


AVES. 


357 


millary  pile  (cumulus)  of  white  granular  sub- 
stanre,  which  is  surrounded  by  a  whitish  zone, 
and  is  continuous  with  the  granular  stratum 
applied  to  the  internal  surface  of  the  membrana 
vitelli,  but  not  adherent  to  that  membrane. 

The  common  envelope  of  the  germinal  vesi- 
cle, cicratricula,  and  yolk,  is  called  the  mem- 
brana vitelli.  It  is  extremely  delicate  and 
transparent,  without  any  perceptible  organi- 
zation, and  forms  an  entire  or  shut  sac.  It  is 
at  first  scarcely  distinguishable  from  the  stra- 
tum of  granules  forming  the  periphery  of  the 
yolk,  and  at  this  period  the  germinal  vesicle 
closely  adheres  to  it.  Subsequently,  however, 
a  separation  is  effected  by  an  interposed  stra- 
tum of  granules.  The  external  membranes  of 
the  ova  are  thick  in  proportion  to  the  vitelline 
membrane,  and  can  with  difficulty  be  detached 
from  without  lacerating  it. 

The  part  of  the  ovary  in  which  the  ovum  is 
lodged  is  termed  the  calyx  (a,  a,  fig.  185). 
It  consists  of  two  membranes;  the  external 
one  is  highly  vascular;  the  internal  one  is 
somewhat  smooth  and  pellucid,  and  is  beset 
with  equidistant,  minute,  and  apparently  glan- 
dular bodies. 

As  the  ovarian  ovum  advances  to  maturity, 
a  pedicle  is  developed  from  which  the  calyx 
with  its  contained  ovum  depends,  and  which 
permits  it  to  be  brought  in  contact  with  the 
infundibular  orifice  of  the  oviduct  (e,Jig.  185). 

The  external  vascular  tunic  of  the  calyx 
then  becomes  covered  with  a  rich  profusion 
of  vascular  twigs  (b,fg.  185)  distributed  in  a 
pectinated  manner,  and  converging  towards  a 
white  transverse  line,  called  the  stigma  (c, 
jig.  185).  This  stigma  begins  to  appear  when 
the  ova  have  attained  the  diameter  of  an  inch, 
in  the  form  of  a  whitish  streak,  which  con- 
tinues to  increase  in  breadth,  and  the 
membranes  at  that  part  to  be  thinned  by 
absorption  until  they  readily  yield,  and  are 
rent  by  the  compressing  force  of  the  infun- 
dibular opening  of  the  oviduct,  when  the 
ovarian  ovum  escapes,  and  is  received  into  the 
efferent  passage. 

The  membrana  vitelli  is  at  this  period 
sufficiently  strong  and  ductile  to  permit  the 
ovum  being  compressed  into  an  elliptical 
form  to  facilitate  its  passage  through  the  con- 
tracted part  of  the  oviduct  (f),  but  during 
this  process  Purkinge  conjectures  that  the 
germinal  vesicle  of  the  cicatricula  is  ruptured 
and  its  pellucid  contents  diffused.  It  is 
certain  at  least  that  it  can  no  longer  be  de- 
tected either  in  the  cicatricula  of  the  ovum  of 
the  oviduct,  or  in  that  of  the  excluded  egg. 
The  further  changes  which  take  place  in  the 
generative  product,  now  no  longer  forming  a 
part  of  the  maternal  system,  will  be  described 
in  the  article  GENERATION  ;  and  we  resume 
the  consideration  of  the  female  organs. 

The  calyx  of  the  ovum,  when  emptied  of  its 
contents  (d,fg.  185)  collapses,  shrinks,  and  is 
ultimately  absorbed,  not  forming  a  permanent 
corpus  luteum,  as  in  Mammalia. 

In  Birds  that  have  but  few  young  at  a  brood, 
as  the  Eagles  or  Doves,  the  number  of  enlarged 


yolks  is  correspondingly  small;  but  in  the  more 
prolific  species,  as  the  Common  Fowl,  they  are 
more  numerous.  The  number  of  young  pro- 
duced may  be,  by  this  means,  in  some  degree 
inferred,  if  the  female  of  a  rare  species  happen 
to  be  killed  during  the  breeding  season. 

The  oviduct  commences  by  the  infundibular 
orifice,  where  its  parietes  are  very  thin ;  as  it 
descends,  these  increase  in  thickness,  and  the 
efferent  tube  gradually  acquires  the  texture  and 
form  of  an  intestine.  Like  this,  it  is  attached 
to  and  supported  by  a  duplicating  of  perito- 
neum called  the  mesometrium,  but  which  also 
includes  muscular  fibres,  to  be  presently  de- 
scribed. 

The  oviduct  in  the  quiescent  state  is  generally 
straight,  but  at  the  period  of  sexual  excitement 
it  is  augmented  in  length  as  well  as  capacity, 
and  describes  three  principal  convolutions  be- 
fore reaching  the  cloaca.  The  lining  membrane 
presents  a  different  character  in  different  parts 
of  the  oviduct;  at  the  infundibular  extremity  it 
is  something  like  the  mucous  coat  of  the  intes- 
tine, then  it  becomes  rugous,  and  afterwards, 
at  the  part  where  the  egg  is  detained  and  the 
chorion  calcified,  it  presents  a  number  of  long 
close-set  villi  (k,fy.  185).  This  part  is  by 
some  anatomists  termed  the  uterus,  but  by  a 
loose  analogy,  as  the  ovum  is  developed  out 
of  the  body  of  the  parent.  The  rest  of  the 
canal,  which,  pari  modo,  is  termed  vagina, 
opens  into  the  urethro-sexual  segment  of  the 
cloaca,  anterior  to  the  termination  of  the  left 
ureter,  and  its  termination  (f,Jig-  164,  176) 
is  provided  with  a  sphincter. 

The  mesometry  (m,  fig.  185)  differs  most 
from  the  mesentery  when  the  female  organs  are 
in  full  sexual  action.  It  presents  at  that  period 
a  true  muscular  structure.  It  is  divided  into 
two  parts,  one  superior,  the  other  inferior. 
The  inferior  mesometry  has  its  point  of  attach- 
ment at  the  lower  part  of  the  uterine  portion 
of  the  oviduct,  and  forms  a  somewhat  dense 
and  cruciform  plexus  of  muscular  fibres  ra- 
diating from  that  part.  The  transverse  fasci- 
culi are  spread  out  on  either  side  and  around 
the  uterus.  The  lower  fasciculus  surrounds 
the  vagina  more  laxly,  and  contributes  to  the 
expulsion  of  the  ovum.  The  upper  fasciculus 
spreads  out  like  a  fan  upon  the  oviduct  from 
its  insertion  into  the  uterine  portion  to  the  com- 
mencement of  the  infundibulum. 

The  superior  mesometry  commences  by  a 
firm  elastic  ligament,  which  is  attached  to  the 
root  of  the  penultimate  rib  of  the  lefl  side, 
whence  the  muscular  fibres  are  continued  to 
the  upper  part  of  the  oviduct,  upon  which 
they  form  a  delicate  muscular  tunic,  whose 
fibres  embrace  the  oviduct  for  the  most  part 
in  the  transverse  or  circular  direction,  except 
at  the  infundibular  aperture,  where  they  affect 
the  longitudinal  direction,  which  enables  them 
to  dilate  that  orifice.  Longitudinal  muscular 
fibres  begin  again  to  be  distinctly  seen  in  the 
uterine  portion  of  the  oviduct,  whence  they  are 
continued  along  the  so-called  vagina.  An  in- 
ternal stratum  of  circular  fibres  is  also  situ- 
ated immediately  behind  the  calcifying  mesr 


368 


AXILLA. 


brane  of  the  uterus.  In  the  vagina  the  circular 
fibres  are  concentrated  at  its  termination  to 
form  the  sphincter  above  mentioned.* 

The  clitoris  in  the  Ostrich  is  continued  from 
the  anterior  margin  of  the  preputial  cavity  of 
the  cloaca,  and  is  grooved  like  the  penis  of  the 
male;  it  has  also  the  same  muscles  inserted 
in  it.  A  corresponding  projection,  as  before 
observed,  is  met  with  in  those  birds  of  which 
the  males  have  a  well  developed  intromittent 
organ. 

BIBLIOGRAPHY. — Perrault,  Description  Anato- 
mique  do  six  oiseaux  appelles  Demoiselles  de 
Numidie,  Mem.  de  Paris,  t.  i.  .et  t.  iii.  Duverney, 
Observation  Anatomique  sur  le  perroquet  arras, 
sur  la  cigogne,  sur  le  casuel,  Mem.  de  Paris,  t.  i. 
Vicq-d'Azyr,  Memoires  pour  servir  a  1'anatomie 
des  oiseaux,  Mem.  de  Paris,  A.  1772,  73,  74,  78. 
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Naturgeschichte  d.  Vbgel,  8vo.  Landsh.  1808-14. 
Nitxsch,  Aufsatzen,  in  Meckel's  Archiv.  B.  i.  B.  ii. 
and  B.  iii.  *  *  *  *  Cotter,  Divers,  animalium 
Bceletorum  explicationes,  fol.  Norimb.  1575.  Camper, 
Memoire  sur  la  structure  des  os  dans  les  oiseaux 
et  de  leurs  diversites  dans  les  differentes  especes, 
Mem.  de  Mathem.  et  Phys.  A.  1773.  Nitsssch, 
Osteographische  Beitrage  zur  Naturgeschichte  d. 
Vogel,  8vo.  Leipz.  1811.  *  *  *  *  Herissant, 
Observations  anatomiques  sur  les  mouvemens  du 
bee  des  oiseaux,  Mem.  de  Paris,  A.  1748.  Yarrell, 
on  the  structure  of  the  beak  and  its  muscles  in  the 
Cross-bill,  ^Mag.  of  Nat.  Hist.  8vo.  Lond.  »  »  »  » 
De  Reaumur,  Sur  la  digestion  des  oiseaux,  Mem, 
de  I'Ac.  des  Sc.  de  Paris,  A.  1752.  *  *  *  *  Bauer, 
Disquis.  circa  nonull.  Avium  systema  arteriosum, 
4to.  fieri.  1825.  Nitzsch,  Obs.  de  Avium  arteria 
carotide  communi,  8vo.  Halae,  1829.  Barkoio, 
Untersuchungen  liber  das  Schlagadersystem  d.Vbgel, 
Meckel's  Archiv.  Jahrg.  1828.  Monro,  State  of 
facts,  &c.  and  on  the  lymphatic  vessels  of  oviparous 
animals,  Edin.  1770.  Hunter  on  the  absorbents 
of  Birds,  in  Phil.  Trans.  1768.  Hewson  on  the 
absorbents  of  Birds,  Phil.  Trans.  1769.  Lauth, 
Mem.  sur  les  vaissaux  lymphatiques  des  oiseaux, 
Ann.  des  Sciences  Nat.  1825.  *  *  *  *  Daubenton, 
Observations  sur  la  disposition  de  la  trachee- 
artere  de  differentes  especes  d'oiseaux,  Mem.  de 
Paris,  A.  1781.  Latham,  Essay  on  the  tracheae, 
or  windpipes,  of  various  kinds  of  birds,  Linn. 
Trans,  v.  iv.  Fuld,  De  organisquibus  aves  spiritus 
ducunt,  4to.  Wirceb.  1816.  Yarrell  on  the  trachea 
of  Birds,  in  Linn.  Trans.  1827.  Hunter,  An 
account  of  certain  receptacles  of  air,  in  birds,  which 
communicate  with  the  lungs,  and  are  lodged  both 
among  the  fleshy  parts  and  in  the  hollow  bones  of 
these  animals,  Phil.  Trans.  Y.  1774.  *  *  *  » 
Holier,  De  cerebro  avium  et  piscium,  Verb.,  van 
het  Maatsch.  te  Haarlem,  Deel  10.  Malacarne, 
Esposizione  anatomica  delle  parti  relative  all'en- 
cefalo  degli  uccelli,  Mem.  de  Verona,  t.  i.  ii.  iii.  iv. 
vi.  vii.  Numan,  De  medulla  spinali  avium,  &c. 
8vo.  Hallae,  1811.  Frank,  De  avium  encephali 
anatome,  8vo.  Berl.  1812,  et  in  Reil's  Archiv. 
B  xi.  *  *  #  *  Vicq-d'Azyr,  De  la  structure  de 
1'organe  de  1'ouie  des  oiseaux,  Mem.  de  Paris,  A. 
1778.  *  *  *  *  Mery,  Observation  sur  le  cercle 
osseux  autour  de  la  cornee  de  1'oeil  de  1'aigle,  du 
corbeau,  et  sur  la  sclerotique  de  1'autruche,  Mem. 
de  Paris,  t.  ii.  p.  24.  Tannenberg,  De  partibus 
genitalibus  masculis  avium,  4to.  Getting.  1789 ; 
Germanice  auct.  4to.  Getting.  1810.  Spangenberg, 
Disq.  circa  partes  foemineas  genitales  avium,  4to. 
Gotting.  1813.  Cuvier,  Le9ons  d'Anat.  Comparee, 
5  vol.  8vo.  passim.  Rees's  Cyclopaedia,  art.  BIRDS, 
by  Macartney. 

(Richard  Owen.) 

-•   *  Purkinje,  Symbola;  ad  Ovi  Avium  Historiam, 
4to.  10.  fig.  19. 


AXILLA  (surgical  anatomy) — (Fr.  Aisselle, 
Ger.  Achselgrube.)  Syn.  region  axillairey  Velp. 
is  the  Latin  name  for  the  armpit,  and  is  used 
by  anatomists  to  designate  an  important  region 
situated  between  the  upper  extremity  and  the 
thorax. 

The  axilla  in  man  is  the  seat  of  so  many 
diseases  and  accidents ;  it  contains  so  large  a 
number  of  nerves,  arteries,  and  lymphatic 
glands ;  and  is  so  frequently  interested  in  sur- 
gical operations,  that  a  pretty  full  description 
of  it  is  allowable  on  the  present  occasion. 

When  the  arm  is  separated  a  little  from  the 
side,  we  observe,  in  the  angle  between  them,  a 
hollow  space,  which,  in  the  adult,  is  always 
covered  with  hair.  This  is,  in  popular  lan- 
guage, the  armpit ;  but  to  the  anatomist  the 
term  axilla  conveys  a  very  different  notion. 
By  him  it  is  understood  to  mean  a  large  region, 
bounded  anteriorly  by  the  greater  and  lesser 
pectoral  muscles,  posteriorly  by  the  subsca- 
pular,  the  teres  major,  and  a  part  of  the  latis- 
simus  dorsi,  and  internally  by  the  ribs,  the 
intercostal  muscles,  and  the  serratus  magnus. 
It  presents  a  basis  below,  formed  of  skin  and 
fascia,  and  an  apex  above,  which  opens  into  the 
cervical  region  between  the  clavicle,  scapula, 
and  first  rib.  Its  walls  form,  therefore,  a  kind 
of  triangular  pyramid,  very  unequal  in  their 
extent,  very  irregular,  and  continually  under- 
going alterations  in  size  and  shape.  Its  height 
is  greater  in  the  male  than  in  the  female,  but 
its  other  dimensions  are  nearly  equal.  It  is 
to  be  found  in  all  animals  which  have  an  upper 
extremity,  and  its  uses  are  subservient  to  the 
motions  of  that  limb. 

In  the  following  description  the  adult  male 
axilla  is  always  supposed  to  be  meant  unless 
otherwise  specified. 

When  the  arm  is  raised  to  the  horizontal 
position,  we  see  the  floor  of  this  region,  the 
base  of  our  pyramid.  This  floor  is  triangular, 
having  its  truncated  apex  at  the  humerus,  its 
base  at  the  side  of  the  thorax,  and  its  sides 
formed  by  the  folds  of  the  axilla,  that  is,  the 
great  pectoral  in  front,  the  teres  major  and 
latissimus  behind.  It  is  concave,  the  concavity 
looking  downwards  and  outwards.  The  skin 
is  fine,  covered  with  hair  at  its  upper  part  from 
the  time  of  puberty,  and  secreting,  by  numerous 
follicles,  a  fluid  of  a  peculiar  odour. 

By  raising  the  elbow  higher  than  the  head  we 
convert  the  concave  into  a  convex,  the  folds  of 
the  axilla  are  removed,  the  skin  made  tense, 
and  the  head  of  the  humerus  by  descending  is 
made  to  touch  the  floor  of  this  region.  Press- 
ing the  arm  close  to  the  side  lowers  the 
floor,  shortens  the  margins,  and  relaxes  all  the 
parts  composing  the  axilla.  When  the  elbow 
is  drawn  a  few  inches  from  the  side,  the 
axillary  artery  and  nerves  may  be  felt  along 
the  humerus,  and  the  head  of  this  bone  may 
be  distinguished.  In  searching  for  disease  in 
the  axilla  the  arm  must  be  placed  in  all  these 
positions,  but  we  are  most  likely  to  detect  any 
abnormal  condition  of  the  parts  when  the  elbow 
is  drawn  a  few  inches  from  the  side,  and  sup- 
ported without  any  effort  of  the  patient. 


AXILLA. 


359 


Immediately  under  the  skin  we  find  some 
cellular  substance,  containing  a  small  quantity 
of  fat ;  and  next  a  fascia  of  considerable  thick- 
ness, which  gradually  loses  itself  on  the  side  of 
the  thorax,  in  the  general  superficial  fascia  of 
the  trunk.  It  will  be  found  extremely  variable 
in  different  subjects,  according  to  the  embon- 
point of  the  individual,  sometimes  loaded  with 
fat,  at  other  times  thin,  firm,  and  somewhat 
aponeurotic,  with  its  principal  bands  stretched 
across  from  the  anterior  to  the  posterior  wall  of 
the  axilla.  In  raising  it,  layer  after  layer  may 
be  removed,  until  it  opens  up  into  that  ex- 
tremely lax  cellular  tissue  which  attaches  itself 
to  the  walls  of  the  axilla,  loosely  supporting 
glands,  vessels,  and  nerves,  and  permitting  all 
the  motions  of  which  this  part  is  capable.  It  is 
obviously  cellular  membrane.  When  enlarged 
glands,  or  abscesses,  or  tumours  of  any  kind, 
form  under  it,  it  readily  yields,  and  stretches 
before  the  distending  force,  never  exerting  any 
painful  pressure  on  them.  The  cellular  tissue 
under  it  is  very  loose.  Numerous  vessels  ra- 
mify through  it  which  are  chiefly  derived  from 
the  thoracica  alaris  artery.  These  vessels  are 
occasionally  ruptured,  when  extensive  ecchy- 
moses  ensue.  Matter  formed  here  passes 
easily  from  one  part  to  another,  and  gives  rise 
to  obstinate  sinuses,  not  easily  remedied  on 
account  of  their  length  and  tortuous  course. 

On  carefully  removing  the  dense  cellular 
membrane  of  the  floor,  and  that  more  loose 
tissue  which  it  conceals,  the  edges  of  the 
axillary  folds  will  be  seen.  Close  to  the  an- 
terior of  them  we  observe  the  thoracica  longior 
artery,  with  its  accompanying  veins  and  several 
lymphatic  glands,  and,  under  cover  of  the 
posterior,  the  subscapular  vessels  and  nerves  ; 
whilst  a  great  bundle  of  arteries,  veins,  and 
nerves,  with  the  biceps  and  coraco-brachialis 
muscles,  stretch  along  the  humerus.  To  this 
view  of  the  parts,  the  operating  surgeon  will 
look  with  peculiar  interest.  It  is  from  below 
that  we  generally  operate  on  the  axilla,  and  the 
three  sets  of  vessels  just  now  mentioned  con- 
stitute the  most  important  subjects  for  consi- 
deration when  the  scalpel  is  to  be  used.  It  is 
obvious  that  free  incisions  may  be  practised  in 
the  centre  of  this  space  or  upon  its  thoracic 
side,  but  that  all  its  other  boundaries  are  beset 
with  dangers. 

To  follow  up  the  anatomy  of  this  region  with 
advantage,  each  of  its  walls  must  be  examined 
in  detail.  The  anterior  wall  consists  of  the 
pectoralis  major  and  minor  muscles.  The 
pectoralis  major  is  a  large  flat  muscle,  of  a  tri- 
angular shape,  extending  over  the  front  of  the 
thorax,  from  the  clavicle  and  sternum  to  the 
humerus. 

The  origin  of  this  muscle  is  curved,  its  con- 
vexity being  directed  upwards  and  inwards;  this 
may  be  called  its  base.  The  insertion  or  apex 
is  outwards  and  downwards.  One  surface 
looks  outwards  and  forwards,  the  other  back- 
wards and  inwards.  The  inferior  margin  extends 
from  the  seventh  rib  to  the  humerus  and  is  nearly 
horizontal,  folded  on  itself  and  free.  The  outer 
edge  is  nearly  vertical,  at  first  about  an  inch  dis- 


tant from  the  deltoid,  but  soon  coming  into  con- 
tact with  it,  and  so  continuing  to  its  insertion. 

The  triangular  space  between  the  deltoid 
and  pectoral  may  be  seen  even  in  the  living 
person  when  the  shoulders  are  shrugged  up, 
especially  if  the  individual  be  thin.  It  is  in  this 
situation  that  the  axillary  artery  commences,  and 
might  be  cut  down  upon  without  dividing  any 
muscular  fibres  except  those  of  the  platysma ; 
it  is  however  protected  by  the  costocoracoid 
ligament,  and  by  the  edge  of  the  pectoral  mus- 
cle. In  this  interval  we  see  the  cephalic  vein 
and  a  small  artery,  the  thoracica  humeraria, 
which  is  the  descending  branch  of  the  thoracica 
acromialis.  The  cephalic  vein  is  derived  from 
a  plexus  on  the  outer  and  back  part  of  the 
hand.  After  various  communications  in  its 
superficial  course  it  gets  between  the  deltoid 
and  pectoral  muscles,  and  on  arriving  at  the 
triangular  interval  above  mentioned,  it  dips  in 
under  the  edge  of  the  great  pectoral  and  just 
above  the  lesser,  to  empty  itself  into  the  axillary 
vein. 

When  the  pectoralis  major  has  been  raised, 
we  bring  into  view  a  stratum  of  cellular  tissue, 
in  which  several  branches  of  the  thoracica 
suprema  artery  and  some  nervous  filaments 
ramify  before  they  enter  the  muscles.  Under- 
neath this  tissue  lies  the  pectoralis  minor,  still 
concealing  the  cavity  of  the  axilla. 

The  posterior  surface  of  the  great  pectoral  is 
not  nearly  so  extensive  as  the  anterior ;  its  fibres 
arise  from  the  cartilages  of  the  ribs,  and,  there- 
fore, the  extreme  limit  of  the  axilla  in  front  is  not 
to  be  estimated  by  the  superficial  dimensions  of 
the  muscle.  A  line  drawn  obliquely  downwards 
and  outwards,  beginning  one  inch  outside  the 
sterno-clavicular  articulation, and  ending  an  inch 
outside  the  nipple,  will  nearly  mark  the  junction 
of  the  anterior  and  internal  walls. 

This  muscle  is  sometimes  torn  across  by  ex- 
ternal violence.  We  have  seen  this  occasioned 
by  the  passage  of  a  railway  carriage  over  it, 
and  marked  by  a  deep  depression,  but  without 
any  laceration  of  the  integuments. 

The  pectoralis  minor  is  shaped  like  the  major, 
but  it  is  considerably  smaller.  Its  base  is  ap- 
plied to  the  ribs,  its  apex  to  the  coracoid  pro- 
cess of  the  scapula.  One  surface  is  turned 
outwards  and  forwards  to  the  greater  pectoral, 
the  other  back  to  the  axilla.  Attached  on  the 
one  hand  to  the  upper  edge  and  the  external 
surface  of  the  third,  fourth,  and  fifth,  and  some- 
times the  second,  true  ribs,  near  their  cartilages, 
by  so  many  distinct  slips,  (hence  its  occasional 
name  serratus  minor  anticus,)  and  an  aponeu- 
rosis  which  covers  the  intercostal  muscles,  it 
terminates  in  a  flat  tendon  which  is  inserted  into 
the  inner  border  of  the  coracoid  process  near  its 
apex.  In  this  situation  it  is  intimately  con- 
nected with  the  coraco-brachialis  and  short  head 
of  the  biceps,  sometimes  sending  fibres  to  be 
continuous  with  the  triangular  or  coraco-acromial 
ligament,  and  in  some  rare  instances  the  entire 
tendon  runs  across  the  coracoid  process,  and 
through  this  ligament  to  join  the  capsulur  liga- 
ment of  the  shoulder-joint.  The  tendon  is 
about  an  inch  broad  ;  very  short  on  the  posterior 


360 


AXILLA. 


surface,  longer  on  the  anterior,  and  longer  still 
at  the  lower  edge.  The  surface  now  exposed 
was  covered  by  cellular  tissue,  and  concealed 
by  the  pectoralis  major  every  where  except  a 
small  part  of  its  lowest  digitation,  which  is 
generally  to  be  seen  below  it,  in  contact  with 
the  integuments. 

The  upper  edge  of  this  muscle  is  nearly  hori- 
zontal, and  placed  about  an  inch  below  the 
clavicle.  In  the  space  between,  when  some 
fat  is  carefully  removed,  and  some  absorbent 
glands,  we  see  the  axillary  artery  running  down- 
wards and  outwards,  internal  and  anterior  to 
which  is  the  axillary  vein,  and  behind  it  the 
nerves.  The  cephalic  vein  is  observed  passing 
upwards  and  inwards  from  the  edge  of  the  del- 
toid muscle  to  the  axillary  vein,  and  the  tho- 
racica  suprema  artery  standing  forwards  from 
the  axillary  artery  and  resting  on  this  edge  of 
the  pectoral.  The  thoracica  acromialis  artery 
runs  in  this  space  out  towards  the  acromion 
process,  and  is  often  a  branch  of  the  suprema. 
Here,  too,  we  see  the  lower  surface  of  the  sub- 
clavius  muscle,  turned  forwards,  and  covered 
by  a  pretty  strong  fascia  which  terminates  in 
the  costo-coracoid  ligament. 

The  coslo-coracoid  ligament  is  very  thin,  but 
strong.  It  extends  from  the  cartilage  of  the 
first  rib,  just  below  the  origin  of  the  subclavius 
muscle,  to  the  coracoid  process  of  the  scapula, 
in  an  arch  across  the  vessels  and  nerves.  It  is 
concave  inferiorly,  and  appears  to  be  only  the 
thickened  edge  of  the  fascia  which  covers  the 
subclavius  and  descends  a  little  below  that 
muscle.  This  view  of  its  true  mode  of  forma- 
tion is  favoured  by  the  fact  that  it  has  an  at- 
tachment also  to  the  clavicle,  and  consequently 
may  be  called  costo-cleido-coracoid.  The  name 
ligamentum  bicorne  is  sometimes  applied  to  in- 
dicate its  horn-shaped  extremities ;  Blandin 
denominates  it  fascia  clavicularis,  and  Gerdy, 
ligament  suspenses  de  I'ai&elle.  As  a  ligament 
it  has  little  power,  but  as  an  aponeurosis  it  pro- 
tects the  vessels,  and  sends  down  a  thin  process 
upon  them. 

Below  the  lesser  pectoral  the  vessels  and 
nerves  again  come  into  view,  and  the  thoracica 
longior  or  external  mammary  artery  is  seen 
passing  downwards  and  forwards  along  its 
lower  edge.  For  a  fuller  description  of  the  pre- 
ceding muscles,  see  THORAX,  MUSCLES  OF  THE. 
The  inner  wall  of  the  axilla  exhibits  the  ribs, 
intercostal  muscles,  and  serratus  magnus,  with 
some  vessels  and  nerves.  One  of  these  last  is 
remarkable  for  its  length  and  vertical  direction; 
it  lies  on  the  serratus  magnus,  and  appears  as 
if  flattened  against  the  side  of  the  thorax.  It 
arises  generally  by  two  branches  from  the  back 
of  the  anterior  division  of  the  fifth  and  sixth 
cervical  nerves  (counting  eight  in  the  neck).  It 
communicates  with  the  phrenic,  descends  be- 
hind the  brachial  plexus,  under  the  clavicle  and 
trapezius,  appears  upon  the  serratus  magnus, 
on  which  it  runs  a  great  distance  and  enters  its 
lowest  division  by  many  filaments.  It  is  classed 
among  the  respiratory  nerves  by  Sir  Charles  Bell, 
by  whom  it  has  been  named  the  inferior  ex- 
ternal respiratory  nerve  of  the  trunk,  its  function 


being,  according  to  his  views,  to  associate  the 
muscle  to  which  it  is  distributed  with  the  ge- 
neral respiratory  movements.  It  was  known  to 
antecedent  anatomists  as  the  posterior  thoracic 
branch  of  the  brachial  plexus.* 

Crossing  the  axilla  from  the  thorax  to  the 
arm,  we  see  two  nerves,  frequently  called  nerves 
of  Wrisberg.  They  are  the  external  branches, 
or  co&to-humeral,  of  the  second  and  third  inter- 
costal nerves.  They  pierce  the  external  layer 
of  intercostal  muscles  opposite  the  origin  of  the 
serratus  magnus,  between  the  second  and  third 
and  the  third  and  fourth  ribs,  and  pass  out  ob- 
liquely to  the  arm,  where  they  are  lost  in  the  in- 
teguments on  the  inner  and  back  part  of  the  arm. 
and  elbow.  The  superior  of  them  is  the  larger. 

The  great  vessels  and  nerves  are  seen  pass- 
ing from  the  first  rib  to  the  lower  border  of  the 
teres  major  muscle,  forming  an  arch  whose  con- 
cavity is  downwards.  By  raising  the  arm  to 
the  horizontal  position  we  obliterate  the  arch, 
and  by  supinating  the  hand  strongly  we  bring 
them  more  into  view.  In  the  upper  third  of 
this  curve  the  order  of  the  parts,  proceeding 
outwards,  is,  the  axillary  vein,  axillary  artery, 
and  plexus  of  nerves.  In  the  middle  the  vein 
is  situated  as  before,  and  then  the  nerves  sur- 
rounding and  hiding  the  artery ;  and  in  the 
inferior  third  we  first  meet  the  vein,  then  the 
nerves,  and  lastly  the  artery. 

The  axillary  vein  is  about  three  inches  in 
length,  commencing  a  little  above  the  edge  of 
the  teres  major ;  thence  it  runs  upwards,  in- 
wards, and  forwards  to  the  second  rib,  which 
it  touches,  as  also  some  fibres  of  the  serratus 
rnagnus  there  arising  ;  next  it  gets  on  the  first 
intercostal  muscles,  after  which  it  becomes  the 
subclavian  vein,  crosses  over  the  first  rib,  under 
the  clavicle,  before  the  scalenus  anticus  muscle, 
and  then  enters  the  thorax.  It  is  formed  by 
the  confluence  of  three  veins,  viz.  the  basilic 
and  the  two  vena  comites  which  convey  their 
fluid  from  the  fore-arm,  and  it  is  afterwards  en- 
larged by  the  accession  of  those  veins  which 
accompany,  usually  in  pairs,  the  subscapular, 
the  thoracic,  and  the  circumflex  arteries.  It 
also  receives  the  cephalic  a  little  higher  up,  as 
before  described. 

The  axillary  artery  traverses  this  region 
from  above  downwards  in  a  course  doubly  ob- 
lique, from  within  outwards,  and  from  before 
backwards;  at  its  upper  part  it  rests  on  the 
chest  separated  by  the  serratus  magnus  muscle, 
and  lies  close  under  the  anterior  wall  of  the 
axilla,  whilst  below  it  rests  on  the  subscapularis 
muscle  (posterior  wall),  and  is  very  near  the 
arm.  Its  complicated  relations  with  the  nerves, 
veins,  glands,  &c.  come  more  properly  under 
consideration  in  the  next  article  (AXILLARY 
ARTERY),  to  which  we  refer. 

*  One  or  two  cases  of  paralysis  of  the  serratus 
magnus  muscle  from  injury  to  this  nerve  have  heen 
recorded.  Velpeau  mentions  one,  which  resulted 
from  a  blow  inflicted  on  the  inner  wall  of  the  axilla  : 
a  permanent  projection  of  the  posterior  edge  of 
the  scapula  backwards,  and  inability  to  bring  that 
bone  into  close  apposition  with  the  thorax,  were  the 
signs  on  which  ho  founded  his  diagnosis.  (Sec  Cy- 
clop, of  Pract.  Med.  art.  PARALYLSis.)— ED. 


AXILLA. 


361 


It  is  plain  from  this  view  of  the  parts  that  a 
wound  in  the  axilla,  near  the  clavicle,  might 
penetrate  botli  the  artery  and  vein,  and  be  fol- 
lowed by  aneurismal  varix,  but  that  no  such 
consequence  could  follow  a  puncture  of  these 
vessels  lower  down.  We  see  too  that  there 
would  be  much  difficulty  in  compressing  the 
axillary  artery  through  the  anterior  wall  of  the 
axilla,  (formed  as  it  is  of  the  two  pectorals,)  ex- 
cept in  the  triangular  interval  between  the 
great  pectoral  and  deltoid  muscles  close  to  the 
clavicle,  and  that  the  subclavius  muscle  and 
the  ligamentum  bicorne  would  bear  off  pres- 
sure even  there  to  a  great  extent.  In  this  place 
the  vein  and  artery  lie  closer  to  each  other  than 
they  do  above  the  clavicle,  a  circumstance  to 
be  remembered  in  attempting  to  command  the 
circulation  of  the  limb.  Collections  of  pus  are 
often  met  with  in  the  cellular  tissue  under  the 
great  pectoral  muscle.  In  children  they  will 
frequently  be  found  to  have  been  occasioned 
by  laceration  which  the  tissue  has  suffered  in 
the  act  of  raising  them  up  by  the  arm.  These 
abscesses  elevate  the  muscle  considerably,  and 
do  not  always  point  in  the  lower  part  of  the 
axilla  as  might  be  expected.  They  approach 
the  surface  directly  in  front  in  some  cases.  But 
if  an  early  opening  were  not  made,  it  is  pro- 
bable they  would  oftener  extend  themselves  all 
through  the  axilla. 

The  nerves  in  the  axilla  are  large,  numerous, 
and  complicated.  The  principal  ones  are  in  a 
bundle,  at  first  behind  the  axillary  artery  and 
then  surrounding  it.  They  arise  in  the  cervical 
region,  interlace  in  a  remarkable  way  to  form 
the  axillary  or  brachial  plexus,  give  off  some 
branches  in  the  neck,  and  on  reaching  the  axilla 
separate  to  supply  the  arm,  forearm,  and  hand. 
(For  a  particular  description  of  this  plexus 
we  refer  to  the  article  CERVICAL  NERVES.) 
The  nerves  we  meet  with  in  the  axilla,  besides 
the  costo-humeral,  are,  three  thoracic  branches, 
three  subscapular,  and  six  others  of  much 
greater  size,  viz.  the  external  cutaneous,  median, 
internal  cutaneous,  ulnar,  musculo-spiral,  and 
circumflex. 

The  thoracic  branches  are  most  commonly 
three  in  number  ;  the  anterior,  arising  from  the 
seventh  cervical,  runs  in  front  of  the  great  ves- 
sels and  is  lost  in  the  pectoralis  major  and 
pectoral  is  minor  muscles ;  the  middle)  very 
small,  passes  under  the  vessels  and  is  lost  in 
the  lesser  pectoral ;  the  posterior,  the  largest, 
is  the  respiratory,  and  has  been  already  de- 
scribed. 

The  subscapular  branches  are  also  three  in 
number  generally ;  they  come  from  different 
points  at  the  upper  and  back  part  of  the  plexus: 
the  smallest  quickly  enters  the  subscapular 
muscle  :  the  other  two  sometimes  arise  by  a 
common  trunk,  or  one  of  them  comes  from  the 
circumflex,  both  run  along  with  the  sub- 
scapular  artery,  the  larger  pierces  the  teres 
major  and  is  lost  in  the  latissimus  dorsi,  the 
smaller  is  distributed  to  the  subscapularis,  teres 
major  and  teres  minor. 

The  external  cutaneous,  or  perforam  Cotterif, 
comes  from  the  external  part  of  the  plexus, 


chiefly  from  the  fifth  and  sixth  cervical  branches, 
and  leaves  the  axilla  by  running  downwards  and 
outwards.  It  is  superficial  and  external  to  the 
axillary  artery. 

The  median  arises  from  the  front  of  the 
plexus  by  two  roots,  one  of  which  is  placed  on 
each  side  of  the  artery  ;  they  soon  unite,  the 
nerve  then  lies  on  the  artery,  and  inclining  a 
little  outwards  escapes  from  the  axilla,  being 
destined  principally  for  the  hand. 

The  internal  cutaneous  issues  from  the  inter- 
nal and  inferior  part  of  the  plexus,  lies  very  su- 
perficially along  the  inner  side  of  the  artery, 
and  quits  the  axilla  where  the  basilic  vein  is 
entering. 

The  ulnar,  arising  from  the  internal  and  pos- 
terior part  of  the  plexus,  inclines  backwards, 
separating  itself  slowly  from  the  inner  side  of 
the  artery. 

The  musculo-spiral  arises  still  farther  back, 
and  is  concealed  from  view  by  the  other 
nerves. 

The  circumflex  nerve  arises  above  and  be- 
hind all  the  others,  and  completely  concealed 
by  them  ;  it  descends  before  the  subscapular 
muscle  for  a  little,  then  turns  backwards  and 
outwards,  close  to  the  capsular  ligament  of  the 
shoulder-joint,  and  in  company  with  the  pos- 
terior circumflex  artery  ;  then  it  appears  on  the 
outside  of  the  neck  of  the  humerus,  between 
the  long  head  of  the  triceps,  the  bone,  and  the 
teres  major  and  minor  muscles,  and  soon  enters 
the  deltoid  in  two  branches.  The  situation  of 
this  nerve  accounts  for  the  paralysis  of  the  del- 
toid muscle  which  sometimes  follows  dislo- 
cation of  the  head  of  the  humerus  into  the 
axilla. 

Lymphatic  glands  are  found  in  great  num- 
bers in  the  axilla;  some  are  scattered  over 
the  internal  wall,  but  there  the  majority  of  them 
will  be  found  in  a  chain  along  with  the  external 
mammary,  or  thoracica  longior  artery.  On  the 
posterior  wall  they  form  a  chain  also,  in  the 
course  of  the  subscapular  vessels.  Some  will 
be  seen  above  the  lesser  pectoral,  and  several 
along  the  axillary  vein.  Hound  this  last  vein 
we  see  numerous  lymphatic  vessels  twining. 

When  the  clavicle  has  been  detached  "from 
its  connexion  with  the  trunk,  and  along  with 
the  scapula  raised  from  the  side,  the  serratus 
magnus  may  be  seen  to  form  the  greater  part  of 
the  internal  wall,  but  extending  far  below  it. 
This  is  a  flat  irregularly  quadrilateral  muscle ; 
one  surface  of  it  is  in  contact  with  the  side  of  the 
thorax ;  the  other,  looking  externally,  touches 
the  subscapular  muscle,  the  axillary  vessels  and 
nerves,  the  two  pectorals,  the  latissimus  dorsi, 
and  the  integuments.  The  anterior  edge  pre- 
sents a  convexity  forwards,  and  consists  of  digi- 
tations  or  fleshy  slips  which  arise  from  the  first 
eight  or  nine  ribs.  The  fibres  all  run  back  to 
the  posterior  margin  of  the  scapula,  along  the 
whole  of  which  they  are  inserted. 

The  thoracic  surface  of  the  muscle,  which 
may  be  seen  by  cutting  through  the  trapezius 
and  rhomboid  muscles,  and  pulling  out  the 
base  of  the  scapula  from  the  ribs,  rests  on 
loose  cellular  tissue,  which  connects  it  with 


362 


AXILLA. 


the  ribs,  intercostal  muscles,  and  serratus  pos- 
ticus  superior. 

The  posterior  wall  of  the  axilla  is  formed  by 
the  subscapular  muscle,  the  teres  major  and 
the  latissimus  dorsi,  to  which  the  long  head  of 
the  triceps  may  be  added.  Along  the  inferior 
margin  of  the  subscapular  muscle,  the  subsca- 
pular artery  runs.  This  is  a  vessel  of  considerable 
size,  and  deserves  the  attention  of  the  surgeon. 
It  arises  from  the  axillary  artery  at  the  tendon  of 
the  subscapular  muscle,  and  passes  all  along 
the  inferior  or  anterior  edge  of  this  muscle  to 
the  inferior  angle  of  the  scapula,  where  it  ter- 
minates by  branches  which  supply  the  muscles 
connected  with  that  point.  The  teres  major  is  a 
long,  flat  muscle,  strap-shaped,  one  inch  and 
a  half  or  two  inches  in  breadth,  extending  from 
the  inferior  angle  of  the  scapula,  to  the  poste- 
rior margin  of  the  bicipital  groove  of  the  hu- 
merus. Its  lower  edge  is  in  part  covered 
by  the  latissimus  dorsi  and  then  by  the  inte- 
guments, and  forms,  principally,  the  poste- 
rior fold  of  the  axilla.  The  posterior  surface  is 
covered  by  the  latissimus,  nearer  the  arm  by 
the  integuments,  and  then  by  the  long  head  of 
the  triceps  and  the  humerus.  Its  anterior  sur- 
face corresponds  to  the  subscapular,  latissimus, 
coraco-brachialis,  biceps,  and  the  axillary  ves- 
sels and  nerves. 

The  latissimus  dorsi  forms  a  very  small  part 
of  the  axilla ;  we  see  it  passing  over  the  inferior 
angle  of  the  scapula  and  twisting  round  the 
teres  major,  so  that  its  posterior  surface  be- 
comes anterior,  and  the  tendon  in  which  it 
ends  gets  internal  to  that  of  the  teres.  Its 
edge  does  not  go  quite  so  low  as  that  of  the  teres 
major,  but,  except  there,  it  prevents  that  muscle 
from  touching  the  axillary  vessels.  It  is  some- 
times connected  to  the  great  pectoral  by  a  fleshy 
slip  which  passes  across  the  axilla. 

The  axilla  has  all  the  conditions  which  ex- 
pose a  part  to  frequent  disease ;  a  position 
which  puts  it  in  the  way  of  many  external 
injuries;  an  important  joint  closely  related 
to  it ;  bones,  liable  to  fracture  ;  arteries,  veins, 
and  nerves  of  great  size ;  numerous  lymphatic 
glands,  connected  with  the  most  delicate  parts 
of  the  body,  lying  in  it ;  and  then  a  quantity 
of  cellular  tissue,  loose,  vascular,  and  con- 
stantly undergoing  alterations. 

To  the  observations  made  on  these  points 
in  the  course  of  the  present  article,  we  shall 
now  make  a  few  additions. 

Wounds  penetrating  into  the  axilla  endanger 
the  nerves,  artery,  and  vein,  if  inflicted  near 
the  humerus  below,  or  close  to  the  clavicle 
above.  In  the  latter  situation,  as  mentioned 
before,  they  may  give  rise  to  aneurismal  varix. 
At  the  lower  margin  of  the  anterior  wall  the 
external  mammary  artery  may  be  injured,  and 
along  the  inferior  border  of  the  posterior  wall 
the  subscapular  vessels  lie  exposed. 

The  shoulder-joint  is  more  liable  to  disloca- 
tion than  any  other  in  the  body,  and  in  most 
cases  the  head  of  the  humerus  comes  into  the 
axilla.  The  great  vessels  and  nerves  are  dis- 
placed inwards,  the  circumflex  vessels  and 
nerve  often  torn.  The  head  of  the  humerus 


lies  just  below  the  subscapular  muscle,  and 
forms  a  tumour  in  the  axilla  easily  felt  from 
below.  (See  SHOULDER,  ARTICULATIONS  OF 
THE.) 

The  neck  of  the  humerus  is  often  broken 
above  the  insertion  of  the  arm-pit  muscles. 
The  lower  fragment  is  drawn  inwards  by  them 
and  upwards  by  the  deltoid,  whilst  the  supra- 
spinatus  directs  the  upper  fragment  out.  In 
this  state  of  things  the  rough  extremity  of  the 
lower  piece  irritates,  perhaps  lacerates  the  ves- 
sels and  nerves,  and  if  not  properly  managed 
leaves  a  permanent  osseous  tumour  in  the  axilla. 

Collections  of  matter  are  very  frequently 
met  with  in  the  axilla.  These  occur  either 
about  inflamed  glands,  or  in  the  cellular  tissue 
connected  with  these  glands,  or  they  may  have 
found  their  way  into  this  region,  their  focus 
being  somewhere  else.  The  abundance  of  cel- 
lular membrane  here,  its  vascularity,  its  in- 
cessant movements,  and  the  dragging  and 
stretching  to  which  it  is  exposed,  render  it 
very  liable  to  formations  of  pus.  Irritation 
of  the  delicate  integuments  may  occasion  them, 
and  they  may  be  formed  in  the  neck  and  pass 
into  this  region  through  the  opening  at  its 
apex.  The  looseness  of  the  texture  is  such 
as  to  allow  suppurations  to  go  on  to  a  great 
extent,  whilst  the  movement  of  the  walls  pre- 
disposes to  their  termination  in  sinuses. 

The  absorbent  glands,  however,  are  the  or- 
gans which  most  frequently  take  on  disease 
in  this  place.  These  may  become  inflamed 
and  enlarged  from  sympathy  with  disease  or 
injury  in  any  part  of  the  corresponding  limb, 
the  back,  the  surface  of  the  thorax,  or  the  upper 
part  of  the  abdomen.  When  inflamed,  they 
often  run  on  to  suppuration,  or  resolution  may 
follow  on  the  removal  of  the  exciting  cause. 
Slight  lesions  of  the  skin  of  the  parts  men- 
tioned may  determine  the  formation  of  ab- 
scesses, as  a  scratch  on  the  finger,  a  blister  on 
the  chest,  &c.  Paronychia  is  not  an  unusual 
exciting  cause. 

Formidable  inflammations  of  these  glands, 
often  attended  with  fatal  consequences,  follow 
the  absorption  of  poisons.  The  cases  most 
familiar  to  us  in  this  country  arise  from  wounds 
received  in  dissecting.  The  glands  seem  to 
arrest  the  poison  in  its  progress  to  the  circu- 
lation. They  become  excited  and  congested. 
The  cellular  tissue  surrounding,  imbedding, 
and  partly  forming  them,  inflames ;  a  puffy 
swelling  marks  the  effusion  of  serum  into  the 
cellular  membrane,  which  may  or  may  not  be 
followed  by  suppuration. 

The  glands  frequently  take  on  the  disease 
under  which  the  neighbouring  mamma  labours, 
as  cancer,  fungus  haematodes,  &c.  These 
must  be  removed  if  the  breast  be  amputated. 
They  are  generally  in  the  course  of  the  external 
mammary  artery,  and  no  other  vessel  is  in- 
terested in  their  removal,  yet  the  looseness  of 
the  tissue  in  which  they  lie  renders  it  unsafe  to 
cut  the  little  vessels  derived  from  this  incon- 
siderable artery.  Surgeons  usually  twist  or 
tear  away  the  glands,  or  else  apply  a  ligature 
to  the  vessel  before  they  cut  it. 


AXILLARY  ARTERY. 


363 


In  almost  every  disease  in  the  axilla  the  arm 
swells  on  account  of  the  pressure  exerted  on 
the  absorbents  and  veins. 

For  tho  BIBLIOGRAPHY  sec  that  of  ANATOMY 
(INTRODUCTION). 

(Charles  Benson.) 

AXILLARY  ARTERY  (arteria  axillaris). 
This  artery,  which  is  the  continuation  of  the 
subclavian  trunk,  commences  at  the  outer 
border  of  the  first  rib,  beneath  the  lower  mar- 
gin of  the  subclavitis  muscle  :  lying  at  first  on 
the  external  surface  of  the  superior  part  of  the 
thorax,  it  traverses  the  axillary  space,  applies 
itself  to  the  internal  side  of  the  upper  extre- 
mity, and  terminates  at  the  lower  edge  of  the 
tendon  of  the  teres  major  muscle.  The  ave- 
rage length  of  this  vessel  is  about  six  inches  : 
when  the  arm  hangs  by  the  side  it  describes  a 
curve  in  its  course,  the  concavity  of  which  is 
downwards  and  inwards,  but  it  is  brought  to  a 
nearly  horizontal  right  line  by  raising  the  arm 
to  a  right  angle  with  the  trunk,  and  it  may  be 
made  to  describe  a  curve,  the  concavity  of 
which  is  turned  upwards,  by  raising  the  arm  to 
the  greatest  possible  extent  of  elevation. 

The  depth  of  this  artery  from  the  surface  is 
greatest  at  its  commencement,  whence  to  its 
termination  it  gradually  becomes  more  superfi- 
cial. 

Relations. — Anteriorly  the  axillary  artery  is 
covered  by  the  following  parts ;  on  first  emer- 
ging from  under  the  margin  of  the  subclavius 
muscle,  it  is  covered  by  the  costo-coracoid  li- 
gament, beneath  which  the  anterior  thoracic 
nerves  coming  from  the  brachial  plexus  cross 
it  in  their  course  to  the  pectoral  muscles,  the 
vessel  then  passes  under  the  pectoralis  minor 
muscle,  from  the  lower  edge  of  which  to  its 
termination  the  coraco-brachialis  lies  in  front 
of  it.  Posteriorly  it  rests  at  its  commence- 
ment on  the  first  intercostal  muscle,  then, 
with  the  interposition  of  a  considerable  quan- 
tity of  cellular  tissue,  on  the  first  digitation 
of  the  serratus  magnus,  which  separates  it 
from  the  external  surface  of  the  second  rib, 
it  next  crosses  the  tendon  of  the  subsca- 
pularis  muscle,  from  the  lower  edge  of  which 
to  its  termination  it  lies  on  the  anterior  sur- 
face of  the  tendon  of  the  teres  major.  Ex- 
ternally it  is  bounded  by  the  lowest  cord  of 
the  brachial  plexus,  until  it  arrives  at  the  supe- 
rior edge  of  the  subscapularis,  and  for  the  re- 
maining part  of  its  course  by  the  commence- 
ment of  the  external  cutaneous  nerve.  Inter- 
nally it  is  bounded  by  the  axillary  vein,  which 
is  in  contact  with  it  in  the  whole  of  its  course, 
except  while  crossing  the  subscapularis,  where 
the  internal  root  of  the  median  and  the  ulnar 
nerve  separate  the  vein  from  the  artery. 

The  lesser  pectoral  muscle,  in  crossing  the 
axilla  at  the  lower  part  of  the  upper  third  of 
that  region,  divides  the  axillary  artery  into  three 
stages.  The  first  extends  from  the  clavicle  to 
the  upper  edge  of  the  lesser  pectoral ;  in  this 
stage  the  most  important  relation  which  the 
artery  has,  is  to  the  vein,  which  lies  upon  its 
inner  side  and  upon  a  plane  anterior  to  it,  so 
that  in  a  state  of  distension  the  vein  would 


overlap  the  artery.  All  the  nerves  are  behind 
and  external  to  it.  In  the  second  stage,  which 
is  that  concealed  by  the  lesser  pectoral,  the 
vein,  still  on  the  thoracic  side  and  more  an- 
terior, is  separated  from  the  artery  by  the 
nerves,  which,  forming  the  axillary  plexus,  are  so 
closely  applied  to  it,  behind  and  on  each  side, 
as  to  form,  as  Velpeau  remarks,  a  complete 
nervous  sheath.  In  the  third  stage,  which  is 
below  the  lesser  pectoral  and  in  immediate 
connexion  with  the  subscapularis  muscle,  the 
artery  is  still  in  the  midst  of  nerves,  having  on 
each  side  a  root  of  the  median,  together  with 
the  external  cutaneous  nerve  on  the  outside 
and  the  internal  cutaneous  and  ulnar  on  the 
inside,  the  circumflex  and  musculo-spiral  being 
posterior  to  it.  In  this  stage  the  vein  is  in- 
ternal and  superficial  to  the  artery,  but  sepa- 
rated from  it  by  the  nerves  which  lie  on  its 
internal  side. 

A  ligature  cannot  be  placed  on  the  axillary 
artery  in  any  stage  of  its  course  without  endan- 
gering parts  of  great  importance ;  in  the  second 
stage,  however,  the  connexion  of  the  artery 
with  the  axillary  plexus  is  so  intimate  as  com- 
pletely to  preclude  the  possibility  of  tying  it 
there  without  incurring  the  greatest  risk  of 
serious  injury.  Hence  there  are  but  two  situ- 
ations in  which  it  can  be  deemed  prudent  to 
expose  this  artery.  Of  these  the  operation  in 
the  third  stage  may  be  accomplished  with 
greater  facility,  because  the  artery  is  here  much 
more  superficial,  and  although  its  relations  are 
numerous,  and  in  some  degree  complicated, 
they  admit  of  being  separated  from  the  artery 
to  such  a  distance  as  will  guard  them  from 
injury.  To  tie  the  artery  in  the  first  stage, 
however,  is  much  more  difficult,  chiefly  in 
consequence  of  the  great  depth  at  which  it 
lies,  the  necessity  there  is  for  cutting  through 
large  muscles,  and  the  almost  certainty  of 
troublesome  and  unavoidable  venous  haemor- 
rhage. The  principal  part  which  the  surgeon 
has  to  avoid  in  applying  the  ligature  needle  is 
the  vein. 

Branches. — The  axillary  artery  usually  gives 
off  six  branches,  viz.;  1.  theacromial;  2.  the 
superior  thoracic;  3.  the  inferior  or  long  tho- 
racic or  external  mammary ;  4.  the  subscapu- 
lar;  5.  the  posterior  circumflex;  6.  the  ante- 
rior circumflex. 

1.  The  acromial  artery  (thoracica  acromia- 
lis)  arises  from  the  anterior  side  of  the  axillary 
artery  above  the  edge  of  the  lesser  pectoral 
muscle,  and  after  having  given  oft  some 
branches  to  the  subclavius,  serratus  magnus, 
and  first  intercostal,  it  passes  obliquely  down- 
wards and  outwards,  piercing  the  expansion  of 
the  costo-coracoid  ligament,  and  arrives  at  the 
posterior  surface  of  the  deltoid  muscle,  where 
it  divides  into  a  superior  and  an  inferior 
branch. 

The  superior  branch  mounts  by  a  tortuous 
course  towards  the  clavicle  ;  this  branch,  which 
is  more  particularly  designated  by  the  term 
acromial,  after  having  given  off  one  or  more 
branches  to  the  deltoid  muscle  and  the  integu- 
ments, runs  along  the  anterior  border  of  the 
clavicle,  behind  the  origin  of  the  deltoid,  until 


364 


AZYGOS. 


it  arrives  at  the  acromial  end  of  that  bone, 
where  it  is  expended  in  a  number  of  branches 
which  go  to  supply  the  scapulo-clavicular  and 
scapulo-humeral  articulations,  and  also  the 
supra-spinatus  and  deltoid  muscles.  This  ar- 
tery anastomoses  with  the  supra-scapular  and 
posterior  circumflex  in  the  vicinity  of  the  acro- 
rnion  process.  The  inferior  or  cephalic  branch 
descends  in  company  with  the  cephalic  vein  in 
the  cellular  interval  between  the  deltoid  and 
pectoralis  major  muscles,  and  is  distributed  to 
these  muscles  and  the  integuments. 

2.  The  superior  thoracic  (thoracic a  suprema, 
Seem.)  is  very  irregular  as  to  the  place  of  its 
origin,  coming  as  frequently  from  the  acromial 
as  from  the  trunk  of  the  axillary;  it  passes  ob- 
liquely forwards  between  the  greater  and  lesser 
pectoral   muscles,    and    divides    into    several 
branches,   which  are  distributed  to  these  two 
muscles,  the  integuments,  and  more  deeply  to 
the  serratus  magnus  and  the  two  or  three  supe- 
rior intercostal  muscles,  anastomosing  with  the 
intercostal  and  internal  mammary  arteries. 

3.  The  inferior  thoracic  (thoracica  longior 
or  mammaria  externa)  is  subject  to  the  same 
variety  of  origin  as  the  superior  thoracic;   it 
sometimes  arises  from  the  subscapular.     This 
artery  descends  on  the  surface  of  the  serratus 
magnus  muscle  along  the  inferior  border  of  the 
pectoralis  major;  its  branches  are  distributed 
to  the  glands  and  cellular  tissue  of  the  axilla, 
to  the  serratus  magnus,  and  pectoralis  major 
and  minor,  and  the  intercostal  muscles ;  it  also 
supplies  the  mammary  gland  and  the  integu- 
ments ;  it  anastomoses  with  the  intercostal,  in- 
ternal mammary,  superior  thoracic,  and  sub- 
scapular  arteries. 

Scemmerring  describes  a  fourth  thoracic  ar- 
tery, under  the  name  of  alaris  sive  axillaris 
glandulosa,*  which  is  distributed  principally  to 
the  axillary  lympathic  glands;  this  artery  is 
very  irregular  in  its  origin,  sometimes  coming 
from  the  trunk  of  the  axillary  artery,  and  as 
often  arising  from  the  thoracica  longior  or  the 
subscapularis.  Instead  of  a  single  artery  going 
to  the  glands  of  the  axilla,  these  parts  are  more 
usually  supplied  by  several  small  twigs  which 
arise  from  the  arteries  in  their  vicinity. 

4.  The  subscapular  artery  is  generally  the 
largest  branch  of  the  axillary ;  it  arises  at  the 
lower  edge  of  the  subscapularis  muscle,  lying 
at  its  origin  behind  the  brachial  plexus;  it  gives 
three  or  four  branches  to  the  glands  and  cellular 
tissue  of  the  axilla  and  to  the  subscapularis 
muscle,  after  which  it  divides  into  two  branches, 
one  inferior,  the  smaller,  the  other,  larger,  called 
the  external  scapular.     The  inferior  branch  de- 
scends along  the  inferior  border  of  the  subsca- 
pularis muscle  and  the  inferior  costa  of  the 
scapula  between  the  latissimus  dorsi  and  the 
serratus     magnus,     to    which     muscles,    the 
teres  major,  and  the  integuments  it  is  finally 
distributed,  anastomosing  with  the  posterior 
scapular   artery  at  the   inferior  angle  of  the 
scapula.      The  external   branch,  circumflexus 
scapula    of    Scemmering,    passes    backwards 
through  a  triangular  space  formed  by  the  sub- 

*  DC  Hum.  Corp.  Fab.  t.  v.  p.  189. 


scapularis  above,  the  tercs  major  inferiorly,  and 
the  tendon  of  the  long  head  of  the  triceps  ex- 
ternally, and  after  having  given  several  branches 
to  these  muscles,  it  divides  into  two  branches, 
a  superficial  and  a  deep-seated ;  the  superficial 
branch  is  distributed  to  the  teres  major,  teres 
minor,  infra-spinatus,  latissimus  dorsi,  and  the 
integuments;  the  deep-seated  branch  winds 
round  the  neck  of  the  scapula  under  the  teres 
major,  and  entering  the  fossa  infra-spinata, 
supplies  the  infra-spinatus  muscle,  the  scapula, 
and  the  scapulo-humeral  articulation.  This 
branch  anastomoses  freely  with  the  branch  of 
the  supra-scapular,  which  descends  under  the 
root  of  the  acromion  process. 

5.  The  posterior  circumflex,  next  to  the  sub- 
scapular,  is  the  largest  branch  of  the  axillary 
artery,  from  the  posterior  side  of  which  it  arises; 
frequently  it  comes  from  the  infra-scapular.    It 
passes  backwards  through  a  quadrilateral  space, 
bounded  in  front  by  the  neck  of  the  humerus, 
behind  by  the  long  head  of  the  triceps,  above 
by  the  subscapularis,  and  below  by  the  teres 
major;  coursing  round  the  neck  of  the  humerus, 
it  passes  below  the  inferior  edge  of  the  teres 
minor,  and  attaching  itself  to  the  under  surface 
of  the  deltoid,  is  principally  distributed  to  that 
muscle,  giving  branches  in  its  course  to  the 
capsular  ligament  of  the  shoulder-joint,   the 
subscapularis,  teres  major  and  minor,  infra- 
spinatus,  and  triceps ;  it  anastomoses  with  the 
supra-scapular  and  acromial  thoracic  by  branches 
which  it  sends  to  the  acromion,  and  with  the 
anterior  circumflex  by  the  branches  which  it 
gives  to  the  articulation  of  the  shoulder. 

6.  The  anterior  circumflex  is  a  very  small 
vessel,  arising  either  from  the  axillary  or  the 
posterior  circumflex ;  it  passes  forwards  round 
the  neck  of  the  humerus  under  the  coraco-bra- 
chialis  and  short  head  of  the  triceps,  to  both  of 
which  muscles  it  gives  branches;  arriving  at  the 
bicipital  groove,  it  sends  off  several  branches, 
some  of  which  descend  along  that  groove,  and 
others  spread  over  the  surface  of  the  head  and 
neck  of  the  humerus,  supplying  that  part  of 
the  bone  and  the  tendons  which  are  inserted 
into  its  tuberosities ;  while  the  continuation  of 
the  vessel  entering  the  bicipital  groove  ascends 
by  the  side  of  the  tendon  of  the  long  head  of 
the  biceps,  passes  under  the  capsular  ligament, 
to  which  and  the  other  parts  entering  into  the 
formation  of  the  shoulder-joint  it  is  ultimately 
distributed.     This  artery  anastomoses  with  the 
posterior  circumflex  and  ascending  branches  of 
the  superior  profunda  of  the  brachial  artery. 

see    that   of    ANATOMY 
ARTERY. 

( J.  Hart.) 


For    the     Bibliography 
(INTRODUCTION)  and  of  > 


AZYGOS,  (a,  fyyo?,  jugum.)  The  term 
azygos  is  applied  by  anatomical  writers  to  cer- 
tain parts  of  the  human  body,  which,  being 
situated  in  or  near  the  mesial  line,  appear 
singly,  and  not  symmetrically  or  in  pairs : 
thus  we  read  of  the  azygos  process  of  the 
sphenoid  bone,  of  the  azygos  uvulae  muscle, 
of  the  azygos  artery,  vein,  &c.  This  term, 
however,  (strictly  speaking,)  is  seldom  very 
correctly  applied,  for  in  the  cases  of  the  bony 


AZYGOS. 


365 


process  and  muscle  quoted,  each  is  composed 
of  parts  that  were  originally  double  or  sym- 
metrical., which  have  coalesced  in  the  middle 
line  so  completely  as  to  appear  single ;  as  to 
the  vessel,  the  description  of  which  will  form 
the  subject  of  the  present  article,  there  is  very 
frequently  an  analogous  trunk,  only  somewhat 
smaller,  on  the  opposite  side  of  the  spine. 

AZYGOS  VEIN,  Posterior  thoracic,  Prelum- 
bo-thoracique,  Vena  sine  part,  Azygos  major. 
This  vein  exists  in  the  posterior  part  of  the 
cavity  of  the  thorax,  on  the  right  side  of  the 
bodies  of  the  dorsal  vertebrae;  it  serves  to 
receive  the  blood  from  most  of  the  intercostal 
spaces,  from  the  phrenic,  bronchial,  and  medi- 
astinal  veins,  as  also  from  the  vertebne  and 
vertebral  sinuses,  and  to  convey  it  into  the 
superior  vena  cava ;  it  also  establishes  a  com- 
munication between  this  last-named  vessel  and 
the  inferior  cava  through  some  of  its  lumbar 
branches,  and  thus  connects  the  veins  of  the 
upper  and  lower  segments  of  the  body,  in  the 
same  manner  as  the  internal  mammary  and 
epigastric,  and  several  others  of  the  thoracic 
and  abdominal  arteries  inosculate. 

In  the  present  article  we  shall  consider  not 
only  the  greater  and  lesser  vena  azygos,  but 
also  the  principal  branches  which  each  receives 
— namely,  the  intercostal  and  bronchial  veins. 
The  right  or  great  vena  azygos  presents  many 
varieties  as  to  the  size  and  number  of  its 
branches,  as  well  as  in  its  exact  origin;  it 
usually  commences  very  small  opposite  the 
first  or  second  lumbar  vertebra,  on  the  upper 
extremity  of  the  right  psoas  muscle  from  the 
confluence  of  several  minute  veins,  which  com- 
municate with  branches  from  the  superior 
lumbar,  capsular,  renal,  and  spermatic  veins, 
and  thus  indirectly  with  the  abdominal  cava ; 
it  not  unfrequently,  however,  arises  by  a  branch 
from  the  cava  itself,  in  which  case  it  appears 
even  in  this  region  as  a  vessel  of  considerable 
size.  The  abdominal  portion  of  the  vena  azygos 
is  but  short,  ascends  obliquely  inwards,  crosses 
the  right  cms  of  the  diaphragm,  and  enters  the 
posterior  mediastinum  between  the  crura  of 
this  muscle  in  company  with,  and  to  the  right 
side  of  the  thoracic  duct  and  aorta ;  it  is  here 
surrounded  by  so  much  cellular  and  adipose 
tissue  as  to  be  frequently  very  indistinct;  it 
sometimes  enters  the  chest  along  with  the  right 
splanchnic  nerve  through  an  opening  in  the 
right  crus  itself,  or  external  to  the  latter,  between 
the  attachments  of  the  diaphragm  to  the  body 
and  transverse  process  of  the  first  lumbar 
vertebra.  The  thoracic  portion  of  the  vena 
azygos  ascends  along  the  right  side  of  the 
vertebral  column  in  front  of  the  right  inter- 
costal arteries,  and  covered  by  the  right  pleura, 
to  which  it  is  closely  connected,  being,  in 
fact,  contained  in  the  subserous  cellular 
tissue ;  the  aorta  is  to  its  left,  and  in  the  in- 
tervening adipose  matter  the  thoracic  duct  is 
placed  ;  the  right  splanchnic  nerve  is  external 
to  it  or  on  its  right  side.  Opposite  to  about 
the  fourth  dorsal  vertebra  the  vein  leaves  the 
spine,  increases  very  much  in  size,  arches 
forwards  and  to  the  right,  around  and  above 


the  right  pulmonary  artery  and  bronchial  tube, 
and  opens  into  the  back  part  of  the  superior 
vena  cava,  immediately  above  the  reflection  of 
the  serous  layer  of  the  pericardium  on  that 
vessel.  A  small  fold  of  the  lining  membrane 
of  the  azygos  vein,  a  mere  rudiment  of  a  valve, 
exists  at  its  junction  with  the  cava ;  sometimes, 
however,  this  fold  is  well  developed,  it  is  even 
observed  to  be  double.  Similar  folds  or  valves 
are  occasionally  found  lower  down  in  the  vena 
azygos,  but  generally  it  is  destitute  of  valves. 
The  vena  azygos  has  been  seen  by  Cheselden 
to  open  into  the  vena  cava  within  the  pericar- 
dium close  to  the  right  auricle ;  it  also  occa- 
sionally opens  into  the  cava  at  a  point  higher 
than  that  which  has  been  stated  as  its  regular 
termination,  and  it  now  and  then  joins  the  right 
or  even  the  left  vena  innominata. 

The  vena  azygos  receives  several  veins;  in 
the  abdomen  and  in  its  passage  through  the 
diaphragm  it  is  joined  by  one  or  two  of  the 
superior  Inmbars,  and  by  small  branches  from 
the  diaphragm;  in  the  thorax  it  receives  the 
intercostals;  the  seven  or  eight  inferior  inter- 
costals  of  the  right  side  enter  it  distinctly ;  the 
corresponding  number  of  the  left  side  some- 
times join  it  in  a  similar  manner,  but  most  com- 
monly they  first  unite  into  a  trunk,  called  the 
left  or  minor  azygos,  of  which  we  shall  speak 
presently.  The  three  or  four  superior  inter- 
costal veins  of  the  right  side  unite  into  one  or 
two  branches  which  end  in  the  convexity  at  the 
upper  extremity  of  the  azygos  major,  which 
also  receives  the  right  bronchial  veins  in  the 
same  situation,  and  at  a  lower  point  the  ceso- 
phageal ;  the  latter,  like  the  arteries  of  the 
same  name,  are  irregular  in  number  and  in 
situation. 

The  left  vena  azygos,  azygos  minor,  semi- 
azygos,  is  smaller,  but  in  other  respects  similar 
to  the  right ;  it  commences  by  small  branches 
from  the  superior  left  lumbar,  capsular,  and 
renal  veins,  which  unite  into  a  delicate  vessel 
that  sometimes  communicates  with  the  right 
azygos,  and  sometimes  with  the  inferior  cava ; 
it  then  passes  through  the  aortic  opening  in 
the  diaphragm,  or  through  or  external  to  its 
left  crus  in  company  with  the  left  splanchnic 
nerve,  and  ascends  along  the  anterior  and  left 
side  of  the  dorsal  vertebrae  as  high  as  the 
seventh  or  eighth ;  it  then  crosses  the  spine 
behind  the  aorta,  oesophagus,  and  thoracic 
duct,  to  join  the  right  or  great  vena  azygos. 
The  azygos  minor  receives  the  six  or  seven 
inferior  left  intercostal  veins,  and  as  it  is 
passing  across  the  spine  it  is  generally  joined 
by  a  large  descending  branch  which  is  formed 
by  the  confluence  of  some  of  the  superior  of 
these  vessels;  the  azygos  minor  also  receives 
the  left  bronchial  veins  as  well  as  some  branches 
from  the  diaphragm,  oesophagus,  and  medias- 
tinum. In  some  subjects  this  vein  is  wanting; 
in  such  cases  the  left  intercostals  join  the  proper 
azygos  either  individually,  or  by  two  or  three 
uniting  into  a  large  branch. 

The  intercostal  veins  are  eleven  or  twelve  in 
number  on  each  side ;  in  their  course  and  dis- 
tribution they  correspond  to  the  intercostal 


366 


AZYGOS. 


arteries ;  they  commence  each  by  the  union  of 
small  branches  near  the  sternum,  which  anas- 
tomose with  the  internal  mammary  veins  ;  they 
then  accompany  the  intercostal  arteries  along 
the  groove  in  the  lower  border  of  each  rib ; 
near  the  spine  they  increase  in  size,  being 
joined  by  several  veins  from  the  exterior  mus- 
cles of  the  spine,  which  pass  through  the 
internal  part  of  each  intercostal  space  along 
with  the  posterior  branches  of  the  intercostal 
arteries  ;  in  this  situation  also  they  receive  veins 
from  the  vertebral  canal,  communicating  with 
the  vertebral  sinuses  on  the  posterior  surface 
of  the  bodies  of  the  vertebrae,  and  passing 
through  the  intervertebral  holes  along  with  the 
spinal  nerves.  All  the  intercostal  veins  com- 
municate with  each  other  over  the  heads  of  the 
ribs,  either  by  many  small  or  by  a  few  larger 
branches ;  the  veins  of  the  opposite  sides  also 
communicate  by  transverse  branches,  so  as  to 
give  to  the  anterior  surface  of  the  dorsal  ver- 
tebrae, in  a  successful  injection  of  the  venous 
system,  an  appearance  somewhat  analogous 
to  the  vertebral  sinuses  on  their  posterior  sur- 
face. The  first  intercostal  vein  of  the  right 
side  generally  ascends  over  the  neck  of  the  first 
rib,  and  over  the  first  dorsal  ganglion  of  the 
sympathetic  nerve,  and  joins  the  subclavian 
vein  or  some  of  its  deep  cervical  branches ; 
the  second  intercostal  frequently  joins  the  first, 
and  sometimes  the  third  also  terminates  in  a 
similar  manner,  but  usually  the  fourth,  third, 
and  often  the  second  open  into  the  arch  of  the 
azygos  by  one  or  two  branches :  these  superior 
intercostal  veins  always  communicate  with  each 
other  and  with  the  azygos  below,  as  well  as 
with  the  subclavian  above.  The  remaining 
intercostal  veins  of  the  right  side  enter  the 
azygos  separately,  or  two  or  three  occasionally 
unite  and  end  by  a  common  opening;  the  infe- 
rior ascend,  the  middle  take  a  transverse  course, 
and  the  superior  descend  ;  near  the  spine  they 
all  anastomose  freely  with  each  other,  so  that 
the  heads  of  the  ribs  support  a  chain  or  net- 
work of  these  vascular  inosculations,  as  is  well 
represented  in  Breschet's  plates  of  the  venous 
system. 

The  superior  intercostal  vein  of  the  left  side 
always  joins  the  left  subclavian  or  some  of  its 
large  branches,  the  internal  mammary  in  parti- 
cular ;  it  is  usually  a  large  vein,  but  it  presents 
great  varieties ;  in  some  it  appears  as  a  third 
vena  azygos,  and  might  be  named  the  left 
superior  azygos;  in  such  cases  it  communicates 
below  with  the  inferior  azygos  about  the  sixth 
dorsal  vertebra  and  above  with  the  left  subcla- 
vian ;  in  the  intermediate  space  it  receives  the 
corresponding  intercostal  veins,  also  the  ceso- 
phagaeal,  mediastinal,  and  left  bronchial ;  this 
vein  sometimes  also  communicates  directly 
with  the  right  azygos.  The  remaining  left 
intercostal  veins  enter  the  lesser  azygos,  or  if 
this  vessel  be  absent,  they  cross  the  spine 
behind  the  oesophagus,  aorta,  and  thoracic 
duct,  and  enter  the  great  azygos  separately,  or 
two  or  three  conjoined.  The  superior  and  in- 
ferior azygos  veins  of  the  left  side  are  some- 
times continuous,  and  enter  the  left  subclavian, 


thus  taking  a  parallel  and  very  similar  course 
to  the  vein  on  the  right  side,  particularly  when 
the  latter  opens  so  high  as  into  either  of  the 
vense  innominatae. 

The  bronchial  veins  arise  in  the  cellular  tissue 
of  the  lungs  from  the  extremities  of  the  bron- 
chial arteries ;  as  the  branches  unite  into  larger 
vessels,  these  are  found  to  accompany  very 
closely  the  divisions  of  the  bronchial  tube ; 
they  leave  the  root  of  each  lung  two  or  three  in 
number ;  on  the  right  side  one  joins  the  arch  of 
the  azygos  or  the  superior  vena  cava,  the  others 
open  into  the  azygos  lower  down,  or  into  some 
of  the  mediastinal  or  intercostal  branches. 
The  left  bronchial  veins  arise  in  a  similar 
manner,  escape  from  the  root  of  the  left  lung, 
and  open  either  into  some  of  the  superior  in- 
tercostal veins,  or  into  the  superior  or  inferior 
azygos  minor.  In  minute  injections  of  the 
lungs  these  veins  are  found  to  inosculate  with 
the  capillary  terminations  of  the  pulmonary 
arteries.  Both  the  right  and  left  vena  azygos 
receive  numerous  branches  from  the  posterior 
mediastinum,  from  the  coats  of  the  aorta, 
pericardium,  oesophagus,  bronchial  glands, 
trachea,  &c.  &c. ;  these  veins  pursue  no  regular 
course;  they  receive  names  either  from  the 
arteries  they  accompany,  or  from  the  organs 
whence  they  are  derived ;  they  require  no  par- 
ticular description. 

The  vena  azygos  is  the  principal  vein  apper- 
taining to  the  parietes  of  the  chest;  it  not 
only  serves  to  receive  the  several  branches 
which  have  been  mentioned,  but  also  maintains 
numerous  communications  between  different 
portions  of  the  venous  system,  which  must 
prove  of  essential  service  in  case  of  obstruction 
to  the  circulation  in  any  of  the  principal 
trunks  :  thus,  its  abdominal  portion  communi- 
cates either  directly  with  the  inferior  vena  cava, 
or  indirectly  through  the  medium  of  the  lumbar, 
phrenic,  renal,  or  spermatic  veins,  while  its 
thoracic  end  joins  the  superior  cava,  and  at  the 
same  time  anastomoses  on  either  side  with 
the  subclavian  vein  or  some  of  its  branches. 
On  both  sides  of  the  thorax  again  it  inoscu- 
lates by  its  intercostal  communications  not 
only  with  the  internal  mammary,  but  also  with 
the  thoracic  branches  of  the  axillary  veins,  and 
along  the  vertebrae  it  communicates  with  the 
vertebral  sinuses,  opposite  each  foramen  of 
conjunction.  This  vein,  consequently,  ap- 
pears not  only  as  one  of  the  roots  of  the  cava, 
but  also  as  a  loop  or  second  channel  between 
the  two  cavffi,  which,  in  case  of  the  obstruction 
of  either,  more  particularly  of  the  inferior,  would 
convey  the  blood  to  the  heart,  and  thus  obviate 
any  impediment  to  the  venous  circulation  of 
the  lower  segment  of  the  body.  Cases  have 
even  occurred  in  which  the  inferior  cava  has 
been  obstructed  or  nearly  obliterated  by  the 
pressure  of  a  tumour  or  of  a  diseased  liver, 
and  in  these  this  anastomosis,  and  indeed  the 
whole  vena  azygos  have  been  found  greatly 
increased  in  size.  The  vena  azygos  appears 
moreover  to  have  been  formed  as  a  convenient 
means  for  receiving  numerous  venous  branches 
which  could  not  reach  any  of  the  large  vessels 


BACK. 


307 


without  some  more  complicated  provision ; 
thus  the  inferior  intercostal  veins  could  not  join 
the  inferior  cava,  where  the  latter  is  imbedded 
in  the  liver,  without  perforating  the  diaphragm  ; 
neither  could  the  middle  and  superior  inter- 
costal, the  mediastinal,  and  the  bronchial 
veins  arrive  at  the  superior  cava  or  at  the  right 
auricle  of  the  heart  without  a  much  more 
complex  disposition  of  all  these  parts  than 
we  observe. 

For  the  BIBLIOGRAPHY  see  that  of  VENOUS 
SYSTEM. 

(Robert  Harrison.) 

BACK,  REGION  OF  THE  (surgical 
anatomy).  Under  this  denomination,  which  is 
of  Saxon  origin,  it  is  intended  to  describe  the 
posterior  regions  of  the  body  situated  between 
the  head  and  the  pelvis,  including  a  cervical, 
a  dorsal,  and  a  lumbar  region,  varying  in  breadth 
in  these  different  portions,  and  corresponding 
in  length  to  that  of  the  spine.  The  skeleton 
of  this  extensive  region  consists  of  the  spinal 
column,  and  a  portion  of  the  ribs,  and  to  the 
former  of  these  it  is  chiefly  indebted  for  its 
longitudinal  curvatures.  Thus  we  find  it  con- 
cave in  the  cervical  and  lumbar  portions, 
convex  in  the  dorsal.  (See  SPINE.) 

In  its  whole  course  from  the  os  occipitis  to 
the  base  of  the  sacrum,  we  observe  a  central 
depression  occasioned  by  the  prominence  of 
muscular  masses  on  each  side.  In  weak  and 
emaciated  subjects  a  rugged  ridge  takes  the 
place  of  this  depression  ;  the  ridge  is  the  series 
of  spinous  processes  which  have  little  or  no 
muscular  covering,  and  are  hid  when  the  mus- 
cles on  each  side  are  much  developed.  At  the 
junction  of  the  cervical  and  dorsal  portion, 
however,  the  ridge  is  scarcely  ever  obscured, 
because  there  the  spines  are  very  long  and  the 
muscles  thin  ;  and  again,  the  depression  at  the 
top  of  the  neck  is  only  rendered  deeper  by 
emaciation. 

The  length  of  the  cervical  region  is  well  de- 
fined by  the  external  tuberosity  of  the  os  occi- 
pitis above,  and  by  the  prominent  spine  of  the 
last  cervical  vertebra  below.  Its  breadth,  at  the 
upper  part,  extends  from  one  mastoid  process 
to  the  other;  in  the  middle  it  becomes  nar- 
rower, and  inferiorly  it  again  spreads  out 
almost  to  the  acromio-clavicular  articulations. 
Its  length  and  breadth  vary  in  different  indi- 
viduals. In  general  it  is  broader,  propor- 
tionally, in  the  male  than  in  the  female,  espe- 
cially at  the  upper  part,  where,  according  to 
Gall,  it  may  be  considered  a  measure  of  ama- 
tiveness.  At  the  top  of  this  region  we  see  a 
remarkable  depression,  called  the  suboccipital 
fossa,  or  cervical  fossa ;  its  existence  depends 
on  the  absence  of  a  spinous  process  in  the 
atlas,  while  the  muscles  on  either  side,  chiefly 
the  complexi,  stand  out  boldly.  In  fat  persons 
a  quantity  of  adipose  substance  fills  up  this 
hollow  and  nearly  obliterates  it.  The  upper 
third  of  the  neck,  and  in  some  persons  much 
more,  is  covered  with  hair.  This  part  is  tech- 
nically called  nitcha,  a  term  of  Arabian  origin. 
Its  common  appellation  is  nape  of  the  neck. 
(See/g.2.; 


The  dorsal  region  corresponds  in  length  to  the 
twelve  dorsal  vertebra?,  with  their  intcrvertebral 
substances,  and  in  this  dimension  it  is  well  de- 
fined, but  its  breadth  is  not  so  settled  ;  anato- 
mists bound  it  by  the  angles  of  the  ribs  on 
either  side,  while  surgical  writers  extend  it 
somewhat  farther.  This  region  is  convex  from 
above  downwards,  and  from  side  to  side  also, 
if  we  overlook  the  slight  central  depression. 

The  lumbar  region  extends  from  the  last 
dorsal  vertebra  to  the  base  of  the  sacrum,  and 
on  each  side  to  the  outer  margin  of  the  sacro- 
lumbalis  muscle.  These  bounderies  can  gene- 
rally be  seen  and  felt  without  difficulty.  It  is  a 
little  concave  from  above  downwards,  convex,  or 
nearly  plane,  from  side  to  side,  with  the  central 
depression  slightly  marked. 

integuments. — The  integuments  of  the  back 
are  every  where  strong  and  coarse.  They  are 
particularly  so  over  the  spinous  processes, 
where  an  imperfectly  marked  raphe  exists; 
they  are  also  more  fixed  along  that  line  than 
elsewhere,  on  account  of  the  density  of  the 
cellular  tissue  which  connects  them  to  the  su- 
pra-spinal ligament,  and  in  many  subjects  the 
raphe  is  hairy. 

The  sensibility  of  the  skin  is  much  less  on  the 
posterior  than  on  the  anterior  surface  of  the  body ; 
the  nerves  and  vessels  are  not  so  numerous,  nor 
is  its  organization  so  high.  Hence  its  resistance 
to  the  action  of  vesicatories  and  rubefacients, 
which  must  be  stronger,  or  applied  for  a 
longer  period  to  produce  the  required  effect. 
The  skin  is  also  very  unyielding,  so  that  col- 
lections of  matter  do  not  readily  make  their 
way  to  the  surface,  and  if  not  opened  early  may 
spread  under  it  extensively. 

Subcutaneous  cellular  tissue. — On  raising  the 
integuments  a  layer  of  cellular  substance  is 
observed,  not  containing  much  fat.  It  is  strong, 
coarse,  and  filamentous,  and  adheres  to  the 
skin  more  than  to  the  muscles.  In  passing  a 
seton  in  the  neck  we  pinch  it  up  with  the  skin, 
and  transfix  it  without  touching  the  muscles, 
which  could  not  be  wounded  with  impunity. 
Along  the  middle  line  this  fascia  is  more  con- 
nected to  the  deeper  parts  than  it  is  on  either 
side,  and  especially  in  the  dorsal  region. 

This  cellular  tissue  is  frequently  the  seat  of 
post-mortem  congestions  and  effusions  arising 
from  the  gravitation  of  the  fluids  to  so  depen- 
dent a  position;  hence  we  generally  find  it 
either  very  vascular  or  infiltrated  with  fluid, 
in  a  state  quite  resembling  anasarca. 

A  very  fine  layer  of  cellular  tissue,  under- 
neath this  again,  closely  adheres  to  the  mus- 
cular fibre,  and  a  good  deal  of  motion  may  take 
place  between  these  two  layers. 

The  arteries  which  supply  the  skin  and  fascia 
in  the  neck  are  branches  of  the  occipital,  the 
cervicalis  profunda,  and  the  transversalis  colli, 
to  which  the  vertebral  and  transversalis  humeri 
may  contribute  a  little.  In  the  dorsal  region 
the  posterior  scapular  and  the  dorsal  branches 
of  the  intercostals  principally  supply  these 
parts ;  and  in  the  lumbar  region  we  have  the 
posterior  branches  of  the  lumbar  arteries. 
None  of  these  approach  the  skin  in  their  undi- 
vided state,  so  that  superficial  wounds  here  can 


368 


BACK. 


never  be  followed  by  troublesome  haemorrhage. 

In  the  fascia  we  generally  tint!  a  vein, described 
by  Godman  of  Philadelphia  under  the  name 
of  the  dorsal  azygos.  It  arises  at  the  lower 
part  of  the  back  by  irregular  roots,  runs  up 
single  for  some  time  along  the  middle  line, 
and  then  divides  into  two  branches,  one  of 
which  pierces  each  trapezius,  and  enters  into 
the  transversalis  colli  vein.  It  is  small  and  of 
little  importance.  The  other  veins  are  not  of 
sufficient  size  to  deserve  particular  notice ; 
they  are  found  in  company  with  the  arteries. 

Nerves. — The  nerves  of  this  region  are  the 
posterior  branches  of  all  the  spinal  nerves.  The 
cervical  and  brachial  plexuses  also  send  some 
filaments ;  but  its  nervous  supply  is,  like  its 
vascular,  very  scanty. 

Lymphatics, — The  lymphatics,  too,  are  not 
so  numerous  as  elsewhere.  We  trace  them 
running  to  the  cervical,  axillary,  and  inguinal 
glands,  according  to  their  proximity  to  these. 
With  the  exception  of  two  or  three  on  the  cer- 
vical portion  of  the  trapezius,  lymphatic  glands 
are  not  met  with  here. 

The  back  is  peculiarly  subject  to  anthrax  in 
debilitated  constitutions,  and  in  some  cases  the 
tumour  acquires  great  magnitude.  It  some- 
times happens  that  several  anthraxes  occur  in 
succession,  until  a  large  portion  of  the  integu- 
ments and  fascia  is  destroyed,  and  the  patient 
sinks  under  the  disease.  Pressure  is  frequently 
the  exciting  cause.  By  pressure  the  vessels  are 
so  obstructed  that  the  vitality  of  the  part  is 
impaired,  and  its  organization  is  too  low  to 
enable  it  to  recover  from  the  deadening  effects, 
especially  if  the  constitution  be  previously  in- 
jured. Here  too  we  often  meet  with  furunculi : 
they  are  most  common  in  the  nape  of  the  neck. 
Fistulae  in  the  lumbar  region,  depending  on 
diseased  kidney,  sometimes  present  themselves. 
There  is  no  peculiarity  in  the  cutaneous  or 
other  diseases  to  which  it  is  liable  in  common 
with  other  regions. 

BACK,  MUSCLES  OF  THE.— The  mus- 
cles of  the  back  are  very  numerous  and  complex. 
There  is  much  variety  in  their  origins  and  inser- 
tions in  different  subjects,  and  in  many  cases  it  is 
not  easy  to  decide  with  which  of  two  adjoining 
muscles  we  are  to  connect  certain  bundles  of 
fibres ;  a  distinct  impression,  therefore,  is  not 
always  obtained  from  an  examination  of  the 
part,  nor  will  a  repetition  of  the  dissection  pre- 
sent us  with  the  same  view  in  another  subject. 
Hence  it  happens  that  anatomists  differ  as  to 
the  number  of  muscles  to  be  met  with,  some 
dividing  into  two  Or  more  muscles  what  others 
consider  as  one ;  this  proves  another  source  of 
difficulty.  The  names  and  the  enumeration  of 
them,  as  given  by  Albinus,  we  shall  follow 
pretty  closely  :  we  esteem  them  the  best  on 
the  whole,  and  they  have  the  advantage  of  being 
generally  adopted  in  these  countries  :  viz.  the 
trapezius  or  cucullaris,  latissmus  dorsi,  rhom- 
boideus  major,  rhomboideus  minor,  levator  an- 
guli  scapula,  serratus  posticus  superior,  serratus 
posticus  inferior,  splenim  cupitis,  splenius  colli, 
sacro-lum'balis,  longissimus  dorsi,  spinalis  dorsi, 
semi-spinalis  dorsi,  cervicalis  desccndens,  trans- 


versalis colli,    (rachelo-mastoideuS)  complexes, 

spinalis  colli,  multifidw  spina;,  inter-spinales, 
inter-transversales,  rcctus  capitis  posticus  major, 
rectns  capitis  posticus  minor,  obliquus  capitis  in" 
ferior,  arid  obliquus  capitis  superior.  These 
muscles  are  placed  in  pairs,  one  on  each  side 
of  the  median  line  ;  none  of  them  can  be  said 
to  be  exactly  in  the  middle.  We  shall  examine 
them  in  the  order  they  present  themselves  to 
us  in  dissecting. 

We  find  these  muscles  disposed  in  layers, 
and  each  layer  differing  from  the  others  in  the 
shape  or  use  of  the  pieces  which  compose  it. 
Six  such  layers  may  be  enumerated.  Thejirst 
consists  of  the  trapezius  and  latissimus  dorsi, 
muscles  somewhat  triangular  in  form,  and 
destined  to  act  principally  on  the  upper  extre- 
mity. The  second  consists  of  the  rhomboidei 
and  levator  anguli  scapulae.  These  are  qua- 
drangular, approaching  a  square  shape,  and  act 
on  the  scapulae.  The  third  layer  is  formed  of 
the  serrati,  of  similar  shape,  but  acting  on  the 
ribs.  The  fourth  consists  of  the  splenii ;  these, 
more  elongated  than  the  last,  rotate  and  erect 
the  head  and  neck.  The  fifth  layer  is  com- 
posed of  very  long  muscles,  acting  chiefly  as 
erectors  of  the  spine  and  head,  viz.  the  sacro- 
lumbalis,  longissimus  dorsi,  spinalis,  and  semi- 
spinalis  dorsi,  cervicalis  descendens,  transver- 
salis colli,  trachelo-mastoideus  and  complexus. 
The  sixth  layer,  again,  is  formed  of  short  mus- 
cles, rotating  and  erecting  the  head  or  minute 
portions  of  the  spinal  column ;  these  are  the 
recti  and  obliqui  of  the  head,  the  spinalis  colli, 
inter-spinales,  inter-transversales,and  multifidus 
spinae. 

First  layer. — The  trapezius  and  latissimus 
dorsi,  which  form  the  first  layer,  almost  com- 
pletely conceal  all  the  other  muscles  of  this 
region,  and  in  superficial  extent  are  scarcely 
succeeded  by  any  two  muscles  in  the  body. 

The  trapezius  is  thin,  triangular,  and  very 
extensive.  One  of  its  surfaces  is  turned  to  the 
integuments,  and  covered  by  the  superficial 
fascia,  and  by  a  fine  layer  of  cellular  tissue 
which  closely  adheres  to  it.  The  trapezius 
arises  from  the  internal  third  of  the  superior 
oblique  ridge  of  the  os  occipitis,  from  the  liga- 
mentum  nuchse,  and  from  the  spinous  pro- 
cesses of  the  last  cervical  and  of  all  the  dorsal 
vertebras.  The  superior  fibres  run  downwards, 
outwards,  and  a  little  forwards,  the  middle 
transversely,  and  the  inferior  upwards  and  out- 
wards ;  all  converge,  and  are  inserted  into  the 
external  third  of  the  posterior  border  of  the 
clavicle,  the  acromio-clavicular  ligament,  the 
acromion  process,  the  upper  edge  of  the  spine 
of  the  scapula,  and  the  tubercle  which  termi- 
nates this  spine  at  the  base. 

The  origin  of  this  muscle  is  by  tendinous 
fibres  which  are  from  half  an  inch  to  an  inch 
long  in  the  occipital  portion ;  in  the  cervical 
they  are  very  short  until  we  come  down  to  the 
sixth  cervical  vertebra,  where  they  begin  to 
lengthen ;  at  the  first  dorsal  they  are  an  inch 
and  a  half  in  length,  again  they  diminish,  and  at 
the  fourth  dorsal  spine  they  are  scarcely  to  be 
seen ;  but  at  the  tenth  they  again  increase  in 
length,  and  form  a  triangular  tendon.  It  some- 


BACK. 


369 


times  happens  that  this  muscle  has  no  connexion 
with  the  eleventh  and  twelfth  dorsal  vertebra). 
The  long  tendinous  fibres  of  the  two  trapezii, 
at  the  junction  of  the  cervical  and  dorsal  re- 
gions, form  an  ovul  aponeurosis  of  considerable 
size,  called  the  cervical  aponeurotis,  which  is 
supposed  to  give  greater  strength  to  this  part. 
All  the  spinal  origin  has  its  fibres  blended  with 
those  of  the  opposite  muscle,  and  supraspinal 
ligament.  The  insertion  is  by  a  mixture  of 
tendinous  ami  fleshy  slips,  except  at  the  extre- 
mity of  the  spine  of  the  scapula,  where  a  little 
tendon  is  formed  which  glides  over  a  small 
triangular  surface  to  be  inserted  into  the  top  of 
the  tubercle.  The  plane  which  this  muscle 
forms  is  curved  on  the  side  of  the  neck,  and  its 
fibres  are  there  a  little  twisted.  Instead  of  three 
sides  this  muscle  has  actually  five:  1st,  a 
superior;  2nd,  an  internal — these  are  its  ori- 
gins; 3rd,  an  external,  which  is  its  insertion, 
and  two  others  which  are  unconnected,  viz. 
4th,  an  inferior  external,  and  5th,  a  superior 
external.  Of  these  the  first  is  so  short  that  it 
attracts  no  notice ;  the  other  four  are  of  un- 
equal lengths — hence  the  name  trapezius.  But 
the  third  and  fourth  sides  are  so  nearly  in  one 
continuous  line  that  the  whole  muscle  appears 
triangular. 

The  trapezius  covers  the  cornplexus,  the 
splenii,  the  levator  anguli  scapulae,  the  serratus 
posticus  superior,  the  rhomboidei,  the  supra- 
spinatus,  a  small  portion  of  the  infra-spinatus, 
the  latissimus  dorsi,  the  sacro-lumbalis  and 
longissimus  dorsi.  It  touches  all  these  mus- 
cles, and  glides  on  them  by  means  of  a  fine 
cellular  tissue,  which  contains  little  or  no  fat 
except  over  the  supra-spinatus.  The  anterior 
superior  edge  forms  the  posterior  boundary  of 
the  great  lateral  triangle  of  the  neck,  and  at  its 
upper  extremity  is  often  connected  with  the 
sterno-mastoid.  The  two  trapezii  have  some 
resemblance  to  the  monk's  cowl  hanging  over 
the  neck,  hence  the  name  citcullares  often  given 
to  them, 

By  its  superior  fibres  this  muscle  raises  the 
clavicle  and  scapula;  by  its  middle  it  draws 
the  scapula  towards  the  vertebral  column,  and 
by  its  inferior  it  pulls  the  tubercle  of  the  spine 
of  the  scapula  downwards.  If  all  the  fibres  act 
together,  it  will  cause,  the  scapula  to  rotate  on 
the  thorax,  so  as  to  elevate  the  shoulder-joint, 
and  in  this  it  is  powerfully  assisted  by  the  in- 
ferior portion  of  the  serratus  magnus,  as  in 
carrying  heavy  burthens  on  the  shoulder.  It 
serves  to  keep  the  head  from  falling  forwards, 
and  will,  by  its  superior  fibres,  draw  the  head 
to  the  shoulder  and  turn  the  face  to  the  other 
side.  We  use  it  in  shrugging  up  the  shoulders. 
It  becomes  a  muscle  of  inspiration  by  raising 
and  fixing  the  clavicle  and  scapula,  so  that  the 
subclavius,  the  lesser  pectoral,  part  of  the  ser- 
ratus magnus,  &c.  may  elevate  the  ribs.  The 
spinal  accessory  nerve  (the  superior  external 
respiratory  of  the  trunk)  terminates  in  this 
muscle,  and,  according  to  Sir  Charles  Bell, 
associates  it  with  the  other  respiratory  muscles. 

The  ligamentum  nuchte,  from  which  the  chief 
part  of  the  cervical  portion  of  the  muscle  arises, 
is  a  line  of  dense  cellular  tissue,  extending  from 

VOL.  I. 


the  external  luberosity  of  the  os  occipitis  to  the 
spine  of  the  seventh  cervical  vertebra.  It  is 
interposed  between  the  two  trapezii.  A  thin 
septum  extends  from  it  to  the  spines  of  all  the 
cervical  vertebrae.  In  no  part  does  it  deserve 
the  name  of  ligament  in  the  human  subject. 
In  quadrupeds,  however,  especially  where  the 
neck  is  long  or  the  head  very  heavy,  as  in  the 
horse,  stag,  elephant,  &c.  it  is  a  powerful  elastic 
ligament,  resembling  in  structure  the  ligarnenta 
subflava  of  the  spine,  and  is  of  great  impor- 
tance by  supporting  the  head  without  much 
muscular  effort.  In  man  it  is  quite  rudimerital. 

The  trapezius  presents  much  variety  in  differ- 
ent animals.  In  the  carnivoraand  rodentia  the 
clavicular  portion  joins  with  the  masto-humeral, 
(a  muscle  not  found  in  man,)  and  is  separated 
from  the  scapular  portion  by  the  levator  anguli 
scapulae.  In  the  horse  the  only  part  of  the  muscle 
developed  is  that  which  corresponds  to  the  as- 
cending fibres  in  man,  and  which  are  inserted  into 
the  tubercle  at  the  extremity  of  the  spinous  pro- 
cesses. In  the  dolphin  it  is  thin,  covers  all  the 
scapula,  and  is  inserted  into  that  bone  near  its 
neck.  In  the  mole  a  fleshy  bundle  coming 
from  the  loins  replaces  it.  In  birds  it  consists 
of  two  portions,  one  for  the  furca,  the  other  for 
the  scapula.  In  reptiles  there  is  no  trapezius. 

Latts4tnus  dorsi.- — This  muscle  is  also  thin, 
triangular,  and  very  extensive,  covering  the 
lumbar  region,  a  part  of  the  dorsal  and  of  the 
side  of  the  thorax,  and  contributing  to  form  the 
posterior  boundary  of  the  axilla.  It  is  exposed 
by  raising  the  integuments,  superficial  fascia, 
and  lower  angle  of  the  trapezius.  Then  we 
find  it  arising  from  the  tops  of  the  spinous  pro- 
cesses of  six,  (sometimes  of  four  or  five,  some- 
times of  seven  or  eight,)  of  the  inferior  dorsal 
vertebrae,  of  all  the  lumbar  vertebrae  and  from 
the  supraspinal  ligament,  from  the  spines  and 
other  eminences  of  the  sacrum,  from  nearly  the 
whole  posterior  half  of  the  crest  of  the  ilium,  and 
from  the  three  or  four  lowest  false  ribs.  The 
fibres  all  converge,  the  uppermost  running 
transversely,  the  lowest  vertically.  It  is  in- 
serted into  the  posterior  edge  of  the  bicipital 
groove  of  the  humerus. 

The  costal  origin  of  this  muscle  is  fleshy,  all 
the  rest  is  tendinous.  The  tendinous  fibres  on 
the  vertebrae  are  blended  with  those  of  the 
opposite  muscle,  and  on  the  sacrum  and  ilium 
with  the  glutaeus  maximus.  They  form  a  tendon 
of  great  extent,  narrow  on  the  sacrum,  very 
broad  on  the  lumbar  region,  and  again  becoming 
narrow  as  we  ascend  to  the  dorsal.  It  is  to  this 
tendinous  expansion  that  the  name  of  lumbar 
fascia  is  given;  its  fibres  are  for  the  most  part  in 
the  direction  of  the  fleshy  fibres  which  succeed, 
but  they  are  crossed  irregularly  by  some  others. 
This  fascia  covers  and  binds  down  the  lumbar 
muscles,  giving  great  strength  to  the  loins;  it 
is  intimately  connected  with  the  tendon  of  the 
serratus  posticus  inferior,  the  internal  oblique 
of  the  abdomen,  and  the  posterior  tendon  of 
the  transversal  is,  all  of  which  are  inseparably 
connected  with  its  anterior  surface.  The  costal 
origin  is  by  fleshy  slips  which  indigitate  with 
similar  slips  of  the  obliquus  externus  abdominis; 
these  are  so  disposed  that  the  inferior  almost 

2  n 


370 


BACK. 


conceals  the  one  above  it,  and  so  on.  The 
muscle  on  its  way  to  the  Immerus  glides  over 
the  inferior  angle  of  the  scapula,  from  which  it 
receives  a  small  fasciculus  of  fleshy  fibres;  then 
it  bends  under  the  teres  major,  forms  a  tendon 
about  an  inch  broad  and  an  inch  long,  which 
is  connected  at  first  by  cellular  tissue,  and  after- 
wards by  a  bursa  mucosa  to  the  front  of  the 
teres  major;  and  is  inserted  into  the  inner  or 
posterior  edge  of  the  bicipital  groove.  Some 
fibres  of  this  tendon  line  the  groove,  a  few  pass 
up  along  its  edge  to  the  lesser  tuberosity.  The 
axillary  vessels  and  nerves,  the  biceps  and  the 
coraco-brachialis,  are  in  contact  with  its  tendon. 

The  upper  edge  of  the  latissimus  is  nearly 
horizontal,  slightly  curved — its  concavity  up- 
wards and  free.  The  anterior  edge  is  nearly 
vertical,  and  for  the  most  part  free  also.  The 
posterior  or  inner  edge  is  connected  throughout, 
and  takes  an  extensive  irregular  sweep.  On 
raising  the  muscle,  we  shall  find  that  it  was  in 
contact  with  the  serratus  posticus  inferior,  the 
sacro-lumbalis  and  longissimus  dorsi,  the  inter- 
nal oblique  and  transversalis  of  the  abdomen, 
the  inferior  rhomboid,  the  serratus  magnus,  the 
inferior  angle  of  the  scapula,  the  infra-spinatus 
and  teres  major,  also  with  some  of  the  ribs  and 
intercostal  muscles. 

We  sometimes  meet  a  fasciculus  of  muscular 
fibres  passing  from  the  latissimus  dorsi  to  the 
pectoralis  major  across  the  axillary  vessels  and 
nerves.  In  the  Edinburgh  Medical  and  Sur- 
gical Journal,  vol.  viii.  Dr.  Ramsay  states 
that  it  is  found  in  one  subject  out  of  every 
thirty,  and  may  prove  inconvenient  to  the  axil- 
lary artery,  vein,  and  nerves. 

The  latissimus  dorsi  depresses  the  arm,  draws 
it  backwards  and  inwards,  rotates  the  humerus 
so  as  to  turn  the  palm  of  the  hand  first  in- 
wards, then  backwards.  It  serves  to  keep  the 
lower  angle  of  the  scapula  in  its  place.  When 
the  arm  is  raised  and  fixed,  it  draws  the  body 
up,  as  in  climbing,  or  elevates  the  ribs,  as  in 
difficult  respiration.  In  using  crutches  the 
arm  is  fixed  by  grasping  the  handle  of  the 
crutch,  then  the  pectoralis  major  and  latis- 
simus pull  up  the  body  on  the  cross-bar  to- 
wards their  insertions ;  and  when  the  body  is 
so  raised,  it  is  impelled  forwards  by  the  action 
of  this  muscle,  aided  by  the  feet  and  by  the 
body's  own  gravity. 

In  quadrupeds  it  is  a  muscle  of  progression, 
pulling  the  trunk  forwards  to  the  fore-leg,  which 
was  previously  fixed.  The  panniculus  carno- 
sus,  which  is  inserted  close  to  it  into  the  hu- 
merus, assists  in  this  action.  In  birds  it  is 
small,  and  consists  of  two  portions. 

Second  layer. — This  layer  consists  of  the 
rhomboidci  and  leva-tor  anguli  scapula.  They 
are  seen  on  raising  the  trapezius. 

The  rhomboidei  form  a  broad  thin  plane, 
separated  only  by  a  line  of  cellular  tissue  into 
the  minor  and  major,  extending  from  the  spine 
to  the  scapula,  and  nearly  concealed  by  the 
trapezius. 

The  rhomboidens  minor  arises  from  about 
half  an  inch  of  the  ligamentum  nuchte  and 
from  the  spine  of  the  seventh  cervical  vertebra; 
its  fibres  run  downwards  and  outwards  to  be 


inserted  into  the  base  of  the  scapula  at  and  a 
little  above  the  commencement  of  the  spinous 
process  of  that  bone.  The  rhomboideus  major, 
three  or  four  times  as  broad,  arises  from  the 
four  or  five  uppermost  dorsal  spines,  runs 
downwards  and  outwards,  and  is  inserted 
below  the  last  into  the  base  of  the  scapula 
from  its  spinous  process  to  its  inferior  angle. 
These  two  muscles  are  of  the  same  length, 
thickness,  and  appearance  in  every  respect, 
differing  only  in  breadth.  Their  fibres  are 
parallel  to  each  other,  being  tendinous  at  their 
origin,  where  they  are  blended  with  those  of 
the  trapezius,  and  are  inserted  between  the 
serratus  magnus  and  the  supra-  and  infra- 
spinati.  The  insertion  of  the  major  is  peculiar; 
a  tendinous  band  runs  along  the  base  of  the 
scapula  from  its  spine  to  its  inferior  angle,  and 
it  is  into  this>  not  into  the  bone,  that  the  mus- 
cular fibres  are  inserted,,  nearly  at  right  angles. 
This  band  is  attached  only  at  its  two  extremi- 
ties ;  it  is  not  seen  till  we  cut  a  few  of  the 
posterior  fleshy  fibres  which  do  reach  the  bone. 
This  arrangement  is  supposed  to  allow  of 
greater  freedom,  of  anastomosis  between  the 
scapular  vessels.  The  minor  is  overlapped  at 
its  insertion  by  the  levator  anguli  scapulae,, 
in  the  rest  of  its  extent  by  the  trapezius.  The 
major  is  covered  by  the  trapezius  principally ; 
a  very  small  part  of  its  inferior  Angle  is  covered 
by  the  latissimus,  and  between  these  it  is 
separated  from  the  integuments  only  by  the 
superficial  fascia.  The  rhomboids  get  their 
name  from  their  shape.  Their  opposite,  but 
not  their  adjacent  sides  and  angles  are  nearly 
equal.  Their  internal  and  external  edges 
are  attached;  their  superior  and  inferior  are 
free.  The  inferior  edge  of  the  major  is  a  little 
longer  than  any  other.  The  deeper  surface  of 
these  muscles  touches  the  splenii,  the  serratus 
posticus  superior,  sacro-lumbalis  and  longis- 
simus dorsi,  some  ribs  and  intercostal  muscles. 

These  muscles  draw  the  base  of  the  scapula 
towards  the  spine,  acting  with  most  effect  on 
the  inferior  angle,  and  thereby  depressing  the 
point  of  the  shoulder.  With  the  trapezius  they 
draw  the  shoulders  upwards  and  backwards. 

In  the  simiae  the  rhomboids  extend  to  the  oc- 
ciput. In  carnivora  the  levator  major  scapula? 
seems  to  be  their  occipital  portion.  In  the 
horse  the  levator  proprius  scapula  is  the  ante- 
rior part  of  the  rhomboid,  arising  from  the 
ligamentum  nuchae. 

The  levator  anguli  scapula  is  a  long  strap- 
shaped  muscle,  situated  on  the  side  of  the 
neck,  and  extending  from  the  superior  cervical 
vertebras  to  the  upper  angle  of  the  scapula. 
Its  origin  is  by  four  (sometimes  three)  ten- 
dinous bundles  from  the  posterior  tubercles 
of  the  transverse  processes  of  the  four  superior 
cervical  vertebra  ;.  that  which  arises  from  the 
atlas  is  the  largest ;  they  are  intimately  con- 
nected with  the  splenius  colli  behind,  and 
with  the  scaleni  before.  The  fleshy  fibres  pro- 
ceeding from  them  unite,  and  passing  down- 
wards, outwards,  and  backwards,  are  inserted 
into  the  inner  surface  and  posterior  margin  of 
the  scapula,  from  its  superior  angle  to  near  its 
spine.  Here  it  overlaps  a  little  of  the  lesser 


BACK. 


371 


rhomboid,  and  is  so  united  with  the  serratus 
magnus  that  Dumeril  considers  it  a  portion  of 
this  muscle.  The  dissection  of  it  in  some 
quadrupeds  favours  this  opinion,  but  in  man 
it  appears  rather  in  connexion  with  the  rhom- 
boid. 

This  muscle  is  covered  by  the  sterno-mastoid 
at  its  upper  part,  then  by  the  integuments,  and 
afterwards  by  the  trapezius.  It  rests  on  the 
splenius  colli,  cervicalis  descendens,  transver- 
salis  colli,  serratus  posticus  superior,  and  lesser 
rhomboid. 

This  muscle  pulls  the  superior  angle  of  the 
scapula  upwards  and  forwards,  and  by  rotating 
that  bone  on  the  thorax  becomes  a  depressor 
of  the  shoulder-joint.  The  rhomboids  act  with 
it  in  depressing  the  joint;  but  the  inferior 
portion  of  the  serratus  magnus  is  its  direct 
antagonist.  When  the  trapezius  acts  with  this 
muscle,  the  scapula  is  drawn  directly  upwards. 
If  the  scapula  be  fixed,  this  muscle  will  incline 
the  neck  to  its  own  side. 

This  muscle  undergoes  many  modifications 
in  the  different  families  of  the  mammalia.  In 
simite  it  is  inserted  into  the  spine  of  the  sca- 
pula, not  into  its  angle.  In  carnivora  and 
rodentia  it  separates  the  two  portions  of  the 
trapezius,  and  is  inserted  near  the  acromial 
end  of  the  spine  of  the  scapula.  In  the  cat  it 
arises  from  the  basilar  process  of  the  os  occi- 
pitis  and  from  only  one  of  the  cervical  vertebrae, 
the  atlas.  In  the  horse  it  does  not  exist  at  all. 
In  the  dolphin  it  forms  a  thin  tendon  which 
spreads  over  the  scapula.  As  to  birds  and  rep- 
tiles, it  is  replaced  in  them  by  other  muscles. 

Third  layer. — Two  very  thin  muscles,  the 
serratus  posticus  superior  and  serratus  posticus 
inferior,  constitute  the  layer. 

The  serratus  posticus  superior  is  quadrilateral. 
It  arises  by  a  thin  tendon  from  the  lowest  part 
of  the  ligamentum  nucha,  from  the  last  cervi- 
cal and  the  first  two  or  three  dorsal  spines. 
The  fleshy  fibres  which  succeed  form  a  thin 
plane,  pass  dowrnwards  and  outwards,  and  are 
inserted  by  four  digitations  into  the  superior 
border  and  external  surface  of  the  second,  third, 
fourth,  and  fifth  ribs,  a  little  external  to  their 
angles. 

This  muscle  is  covered  by  the  rhomboid, 
the  trapezius,  and,  when  the  shoulder  is  drawn 
back,  by  the  serratus  magnus.  Its  origin  is 
united  to  the  two  former.  It  covers  the  splenii, 
the  longissimus  dorsi,  transversalis  colli,  sacro- 
lumbalis  and  cervicalis  descendens ;  while  on 
these  it  is  tendinous ;  then  it  becomes  fleshy 
and  covers  the  ribs  and  intercostal  muscles. 
Sometimes  it  has  only  three  points  of  insertion. 
Occasionally  we  find  a  bundle  of  fibres  passing 
from  the  upper  part  of  this  muscle  along  the 
levator  anguli  scapulae  to  be  inserted  into  the 
transverse  process  of  the  atlas. 

This  muscle  elevates  the  ribs  and  expands 
the  thorax  as  in  inspiration.  It  binds  down 
the  muscles  on  which  it  lies,  enabling  them  to 
act  with  more  effect. 

The  serratus  posticus  inferior  is  very  like  the 
last  muscle,  but  a  little  broader  and  thinner. 
It  arises  from  the  last  two  dorsal  and  first  three 
lumbar  spines  by  a  thin  tendinous  expansion, 


which  is  intimately  connected  with  the  tendon 
of  the  latissimus  dorsi,  and  often  destroyed  in 
removing  the  latter.  The  fleshy  fibres  which 
succeed  pass  upwards  and  outwards  to  be 
inserted  by  digitations  into  the  four  lowest 
false  ribs.  The  uppermost  digitation  is  the 
largest,  and  is  attached  to  the  rib  near  its  angle ; 
the  others  become  smaller  as  we  descend,  and 
their  insertions  are  more  remote  from  the  angles. 
The  lowest  is  connected  with  the  cartilage  of 
the  last  rib.  This  muscle  covers  the  longissimus 
dorsi  and  sacro-lumbalis,  the  ribs  and  inter- 
costals.  It  also  covers  the  posterior  tendon  of 
the  transversalis  abdomiriis,  to  which  it  is  in- 
separably united. 

This  muscle  draws  down  the  ribs  as  in  ex- 
piration, and  binds  down  the  deep  lumbar 
muscles. 

A  thin  semitransparent  fibrous  layer,  called 
the  vertebral  aponeurosiSj  covers  the  spinal 
muscles  in  the  interval  between  the  two  ser- 
rati.  It  is  continuous  with  their  adjacent  edges, 
and  assists  them  in  binding  down  the  long 
muscles  of  this  region.  The  fibres  of  which 
it  is  composed  pass  for  the  most  part  trans- 
versely, from  the  spinous  processes  to  the  an- 
gles of  the  ribs. 

These  muscles  are  generally  present  in  the 
inferior  animals,  when  ribs  exist,  and  have  no 
peculiarity  worthy  of  being  noticed  here. 

The  splenii  form  the  fourth  layer.  They 
appear  as  one  muscle,  extending  from  the  lower 
cervical  and  upper  dorsal  spines  obliquely 
upwards,  outwards,  and  forwards,  to  the  head 
and  to  the  transverse  processes  of  the  superior 
cervical  vertebras.  Covered  below  by  tha 
rhomboid  and  serratus  posticus  superior,  higher 
up  by  the  trapezius  and  levator  anguli  scapulae, 
and  higher  still  by  the  sterno-mastoid,  it  is 
only  about  the  middle  of  their  course  that  they 
become  distinct  from  each  other,  for  they  arise 
as  one. 

The  splenius  colli  (or  splenius  cervicis)  is 
the  inferior  portion,  not  so  thick  or  broad  as 
the  superior,  but  of  greater  length.  It  arises 
from  the  spines  of  the  third,  fourth,  fifth,  and 
sixth  dorsal  vertebrae,  and  from  the  interspinal 
ligaments,  by  tendinous  fibres  which  are  long, 
and  form  an  acute  angle  below.  The  flat  band 
of  fleshy  substance  which  proceeds  from  this 
tendon  passes  upwards,  outwards,  and  for- 
wards, then  divides  into  two  or  three  fasciculi, 
which  are  inserted  tendinous  into  the  trans- 
verse processes  of  the  two  or  three  superior 
cervical  vertebrae,  blended  with  the  attach- 
ments of  the  levator  anguli  scapulae  and  the 
transversalis  colli. 

The  splenius  capitis,  the  superior  portion, 
arises  from  the  spines  of  the  two  superior 
dorsal  vertebras  and  of  the  seventh  cervical, 
and  from  the  ligamentum  nuchae  as  high  as  the 
fourth  cervical.  At  the  origin  it  is  tendinous  ; 
it  soon  becomes  fleshy,  passes  upwards,  out- 
wards, and  forwards,  to  be  inserted  into  the 
back  part  of  the  mastoid  process  of  the  tem- 
poral bone,  and  into  the  external  part  of  the 
depression  on  the  occipital,  between  the  supe- 
rior and  inferior  transverse  ridges. 

These  two  portions  ought  not  to  be  con- 
2  B  2 


372 


BACK. 


sidered  distinct  muscles.  They  are  inseparable 
below ;  their  structure,  direction,  and  uses  are 
alike ;  and  they  are  inserted  similarly — the  one 
into  transverse  processes,  the  other  into  a  part 
of  the  cranium  perfectly  analogous. 

The  splenii  cover  the  longissimus  dorsi, 
the  complexus,  the  transversalis  colli,  and  the 
trachelo-mastoideus.  The  splenii  of  opposite 
sides  pass  off  from  each  other  as  they  ascend, 
leaving  a  triangular  space  at  the  upper  part  of 
the  neck,  in  which  the  complex!  appear. 

The  action  of  these  muscles  is  to  incline  the 
head  to  one  side,  and  rotate  it.  If  the  sterno- 
mastoideus  of  the  same  side  act  with  them,  the 
head  is  inclined  directly  to  the  shoulder.  If 
the  splenii  of  opposite  sides  act  together,  the 
head  and  neck  are  kept  erect,  and  in  this  they 
are  assisted  by  the  complexus  and  trapezius. 
They  strap  down  the  deeper  muscles.  Their 
name  is  said  to  be  derived  from  some  resem- 
blance to  the  spleen!  (Turtorfs  Glossary.) 

The  splenii  are  generally  better  marked  in 
other  mammalia  than  in  man.  In  the  mole 
they  are  particularly  strong.  In  carnivora 
there  is  no  splenius  colli.  In  the  horse  the 
splenius  capitis  is  inserted  into  the  mastoid 
process  by  a  tendon  common  to  it  and  to  the 
trachelo-mastoideus.  Birds  have  no  splenius. 
Reptiles  have  analogous  muscles;  but  fish 
have  not. 

Fifth  layer. — On  removing  the  splenii  and 
all  those  previously  described,  we  expose  the 
Jift/i  layer  of  muscles,  consisting  of  the  sacro- 
lumbahs,  longissimus  dorsi,  spinalis  and  semi- 
spinalis  dorsi,  cervicalis  descendens,  trans- 
versalis colli,  traehelo-mastoideus,  and  com- 
plexus. These,  excepting  the  last,  are  long 
and  slender,  quite  different  from  those  hitherto 
described.  They  are  also  less  distinct  from 
each  other.  The  first  four  of  them  fill  up  the 
vertebral  groove  from  the  sacrum  to  the  neck, 
and  might  well  be  considered  as  one  muscle — 
the  erector  spirits. 

The  sacro-lumbalis  y  placed  most  externally, 
arises  from  the  posterior  surface  of  the  sacrum, 
from  the  margin  of  the  ilium  where  the  latter 
overlaps  the  former,  from  the  sacro-iliac  liga- 
ments, and  from  the  extremities  of  the  trans- 
verse processes  of  the  lumbar  vertebrae ;  pas- 
sing upwards,  and  tapering  in  form,  it  is  in- 
serted by  tendinous  slips  into  the  angles  of  all 
the  ribs.  It  is  reinforced  in  its  ascent  by  acces- 
sory fibres  (musculi  accessor ii),  which  arise  at 
the  upper  margins  of  the  five  or  six  lowest  true 
ribs,  internal  to  their  angles,  run  upwards  and 
outwards  over  one  or  two  intercostal  spaces 
under  cover  of  the  longer  fibres,  and  are  in- 
serted with  them  into  the  angles  of  the  ribs. 
These  accessory  fibres  constitute  almost  the 
entire  of  the  muscle  at  its  upper  part. 

The  longissimus  dorsi,  placed  along  its  inner 
side,  arises  from  the  spinous  and  transverse 
processes  of  the  lumbar  vertebrae,  and  from  the 
spines  of  the  sacrum  and  its  posterior  surface 
down  to  its  apex.  It  forms  a  thick,  somewhat 
square,  mass  in  the  loins ;  on  the  dorsum  it 
becomes  fiat  and  tapering,  and  ends  in  a  point 
at  the  top  of  the  thorax.  It  is  inserted  by  two 
rows  of  tendinous  and  fleshy  slips — one  row 


into  the  transverse  processes  of  all  the  dorsal 
vertebrae,  the  other  row,  externally,  into  the 
lower  edge  of  the  ribs  near  their  articulations 
with  those  processes.  The  costal  slips  are 
seldom  inserted  into  all  the  ribs,  the  first  two 
or  three  and  the  last  two  or  three  being  often 
without  them. 

The  posterior  surface  of  these  two  rmiscles 
consists  below  of  a  strong  tendinous  layer,  from 
which  a  great  part  of  their  fleshy  fibres  arises  ; 
it  is  common  to  the  two  as  far  as  the  middle 
of  the  lumbar  region ;  there  it  terminates  on 
the  sacro-lumbalis,  but  ascends  much  higher  on 
the  longissimus  dorsi,  separating  into  several 
distinct  bands,  between  which  vessels  and 
nerves  come  out. 

This  tendon  is  not  to  be  confounded  with 
the  fascia  lumborum,  which  is  much  thinner 
and  adheres  to  its  posterior  surface. 

The  spinalis  dorsi*  lies  close  along  the  spi- 
nous ridge,  arising  from  the  two  superior  lum- 
bar, and  three  inferior  dorsal  spines.  It  forms 
a  thin  muscle  and  is  inserted  into  the  nine 
superior  dorsal  spines.  Below  it  is  in  contact 
with  the  longissimus;  above  it  is  separated 
from  it  by  the  next  muscle. 

The  semi-spinalis  dorsi  arises  from  the  trans- 
verse processes  of  the  dorsal  vertebrae  from  the 
eleventh  to  the  sixth  inclusive  by  so  many 
distinct  tendinous  fasciculi  which  pass  up,  be- 
come fleshy,  unite  and  are  inserted  into  the 
spines  of  the  four  or  five  superior  dorsal  and 
two  inferior  cervical  vertebra.  The  name  of 
this  muscle  is  intended  to  denote  its  attachment 
to  the  transverse  as  well  as  to  the  spinous  pro- 
cesses. It  is  at  first  concealed  by  the  longis- 
simus dorsi,  then  lies  along  the  inner  side  of 
that  muscle  and  the  outer  side  of  the  spinalis 
dorsi,  with  which  last  it  is  often  united  in 
description. 

These  four  muscles  elevate  the  spine,  and 
give  it  an  inclination  to  their  own  side. 
The  sacro-lumbalis  will  also  depress  the  ribs 
slightly. 

The  cervicalis  descendens  looks  like  a  con- 
tinuation of  the  sacrolumbalis,  between  which 
and  the  longissimus  dorsi  it  arises.  Its  origin 
is  by  tendinous  slips  from  the  angles  of  the 
second,  third,  fourth,  fifth,  and  sixth  ribs. 
These  are  at  first  blended  with  those  of  the 
sacro-lumbalis ;  then  they  unite  and  form  a 
slender  muscle,  which  runs  upwards,  out- 
wards, and  forwards,  to  be  inserted  into  the 
transverse  processes  of  the  third,  fourth,  fifth, 
and  sixth  cervical  vertebrae,  between  the  trans- 
versalis eolli  and  the  levator  anguli  scapulae. 

This  muscle  may  elevate  the  ribs  or  extend 
the  neck,  turning  it  to  one  side.  It  is  often 
considered  as  a  portion  of  the  sacro-lumbalis, 
and  sometimes  called  musculus  accessorius, 
or  cervicalis  ascendens.  The  name  cervicalis 
descendens,  that  by  which  it  is  best  known,  was 
given  to  it  by  Diemerbroeck,  who  described 


*  Under  the  denominations  transversaire  epineux, 
which  may  be  latinized  transversus  spines,  Bichat 
and  some  other  continental  anatomists  include  the 
spinalis  dorsi,  semi-spinalis  dorsi,  spinalis  coUi,  and 
mvltifidus  spinee.—  ED. 


BACK. 


373 


it  as  descending  from  the  neck  to  act  on  the  ribs 
and  elevate  them. 

The  transversalis  colli  appears  like  a  con- 
tinuation of  the  longissimus  dorsi,  and  as  such 
is  often  described.  It  arises  along  its  internal 
side  by  tendinous  and  fleshy  slips  from  the 
transverse  processes  of  the  second,  third, 
fourth,  fifth,  and  sixth  dorsal  vertebrae.  These 
unite,  form  a  flat  fleshy  belly,  which  passes 
upwards,  outwards,  and  forwards,  to  be  in- 
serted by  similar  slips  into  the  transverse  pro- 
cesses of  the  cervical  vertebras  from  the  sixth 
to  the  second  inclusive,  between  the  cervicalis 
descendens  and  the  complexus.  The  origin 
and  insertion  of  this  muscle  are  connected  only 
to  transverse  processes — hence  the  name. 

This  muscle  elevates  the  neck  and  inclines 
it  to  one  side. 

The  trachelo-mastoideus  lies  to  the  inner  side 
of  the  transversalis  colli,  by  which  it  is  in 
great  measure  concealed.  It  arises  by  ten- 
dinous slips  from  the  transverse  processes  of 
two  or  three  superior  dorsal,  and  of  three  or 
four  cervical  vertebrae.  The  slender  muscle 
enlarges  as  it  ascends,  passes  a  little  outwards, 
and  is  inserted  into  the  posterior  border  of  the 
mastoid  process,  underneath  the  splenius  ca- 
pitis.  Its  inner  side  rests  on  the  complexus, 
then  it  covers  the  obliquus  capitis  inferior  and 
superior,  and  the  origin  of  the  digastric,  also 
the  occipital  artery.  It  is  by  some  called  the 
complexus  minor,  from  the  resemblance  it 
bears  to  the  complexus  in  its  structure.  Some 
anatomists  consider  it  as  the  cranial  portion  of 
the  longissimus  dorsi  and  transversalis  colli. 
The  origin  of  its  name  is  obvious. 

When  in  action,  this  muscle  extends  the 
neck,  drawing  the  head  back  and  to  its  own 
side. 

The  complexus  is  thicker  and  broader  than 
the  muscles  we  have  been  now  describing  in 
the  cervical  region.  It  arises  from  the  trans- 
verse and  articulating  processes  of  the  four  or 
five  superior  dorsal  vertebrae,  and  from  the 
transverse  processes  of  the  four  inferior  cervical, 
by  tendinous  slips :  these  are  followed  by 
fleshy  and  tendinous  bundles.  The  muscle 
thus  formed  passes  upwards  and  inwards,  to  be 
inserted  into  the  os  occipitis  between  its  supe- 
rior and  inferior  oblique  ridges.  The  complexi 
are  close  to  each  other  above,  separated  only 
by  cellular  tissue  which  is  connected  with  the 
ligamentum  nuchae ;  lower  down,  however, 
there  is  some  space  between  them.  This  mus- 
cle is  covered  by  the  trapezius  above,  by  the 
splenii  in  the  middle,  and  by  the  trachelo- 
mastoideus  and  longissimus  dorsi  at  its  lowest 
part.  It  rests  on  the  spinalis  colli,  the  obliqui 
and  recti  capitis.  The  name  is  derived  from 
the  complicated  intermixture  of  tendinous  and 
fleshy  fibres  of  which  it  is  composed.  A  su- 
perficial portion  of  it  is  described  by  Albinus 
as  the  biventer  cervicisj  but  it  does  not  usually 
admit  of  subdivision. 

This  muscle  draws  the  head  back  on  the 
spinal  column. 

In  the  muscles  of  this  layer  there  are  no 
very  striking  differences  to  be  observed  in  the 


other  mammalia,  nor  in  birds.  Reptiles  and 
fishes  differ  too  widely  to  allow  of  a  com- 
parison. 

Sixth  layer. — On  raising  the  complexus  and 
trachelo-mastoideus  we  observe  a  beautiful 
series  of  muscles  for  moving  the  head,  viz. 
the  inferior  oblique,  the  superior  oblique,  the 
rcctus  capitis  posticus  major  and  minor.  These, 
with  the  spinalis  colli,  form  a  sixth  layer. 

The  spinalis,  or  rather  scmi-spinalis  colli, 
arises  by  four  or  five  fasciculi  from  the  trans- 
verse processes  of  as  many  superior  dorsal 
vertebrae ;  these  unite,  pass  upwards  and  in- 
wards, to  be  inserted  into  the  second,  third, 
fourth,  and  fifth  cervical  spines,  forming  a 
thicker  muscle  than  the  spinalis  or  semi-spinalis 
dorsi. 

This  muscle  commences  between  the  longis- 
simus and  semi-spinalis  dorsi,  then  it  lies  be- 
tween this  last  and  the  complexus.  It  is 
almost  concealed  by  the  complexus.  It  ex- 
tends the  cervical  vertebrae  and  inclines  them 
to  its  own  side. 

The  obliquus  capitis  inferior  arises  from  the 
spine  of  the  second  vertebra,  passes  outwards 
and  a  little  upwards  and  forwards,  to  be  in- 
serted into  the  transverse  process  of  the  first. 
Its  origin  is  connected  with  that  of  the  rectus 
posticus  major,  and  the  insertion  of  the  spi- 
nalis colli.  Its  insertion  is  blended  with  the 
origin  of  the  obliquus  superior.  It  is  fusi- 
form in  shape,  the  largest  of  the  four  muscles 
to  be  met  with  here,  and  is  often  called  obli- 
quus  major.  It  covers  the  vertebral  artery  and 
the  lamina  of  the  second  vertebra,  and  is  itself 
covered  by  the  complexus  and  trachelo-mas- 
toideus, and  by  the  posterior  branch  of  the  first 
cervical  nerve. 

It  rotates  the  first  vertebra  on  the  second, 
thus  turning  the  face  to  its  own  side. 

The  obliquus  capitis  superior  (or  minor)  has 
a  pointed  origin  from  the  transverse  process 
of  the  atlas;  runs  upwards,  inwards,  and  back- 
wards, becoming  broader,  and  is  inserted  into 
the  os  occipitis  between  its  transverse  ridges, 
just  above  the  insertion  of  the  rectus  posticus 
major.  This  muscle  is  covered  by  the  splenius 
capitis,  trachelo-mastoideus  and  complexus. 
It  covers  the  vertebral  artery  and  the  interval 
between  the  atlas  and  occiput. 

Its  action  is  to  extend  the  head,  giving  it 
some  inclination  toils  own  side. 

The  rectus  capitis  posticus  major  is  triangu- 
lar; its  apex  arises  from  the  spine  of  the  deri- 
tita;  it  passes  upwards  and  a  little  outwards,  to 
be  inserted  by  its  base  into  the  inferior  transverse 
ridge  of  the  os  occipitis.  This  muscle  and  its 
fellow  arise  close  together;  passing  up  they 
separate.  The  insertion  is  overlapped  by  that 
of  the  superior  oblique.  The  complexus  covers 
the  greater  part  of  it. 

This  muscle  draws  back  the  head,  turning 
the  face  a  little  to  its  own  side. 

The  two  obliqui,  with  this  last  muscle,  en- 
close a  triangular  space,  in  which  we  see  the 
posterior  branch  of  the  sub-occipital  nerve 
enveloped  in  adipose  tissue,  the  vertebral 
artery,  the  posterior  half  ring  of  the  atlas,  and 


374 


BILE. 


the  thin  ligament  which  connects  this  last  with 
the  edge  of  the  foramen  magnum.  Here  we 
find  the  nerve  dividing  into  three  branches  for 
these  three  muscles. 

On  removing  some  cellular  tissue  from 
between  the  recti  majores,  we  observe  the 

Rectus  posticus  minor,  shaped  like  the  last, 
but  much  smaller.  It  arises  close  to  its  fellow 
from  a  little  tubercle  on  the  back  of  the  atlas, 
passes  upwards,  outwards,  and  backwards, 
to  be  inserted  into  the  os  occipitis  between  the 
inferior  oblique  ridge  and  the  foramen  mag- 
num. It  is  partly  concealed  by  the  rectus 
major.  This  muscle  can  draw  the  head  back- 
wards. 

In  quadrupeds  these  four  muscles  are  pro- 
portionally larger  than  in  man.  The  inferior 
oblique  and  the  rectus  major  are  considerably 
larger.  Birds  have  three  recti,  and  only  one 
oblique — the  inferior.  Reptiles  and  fishes 
may  be  said  to  want  them,  as  the  analogy  is 
very  remote. 

On  removing  the  spinalis  colli  and  all  the 
muscles  of  the  fifth  layer,  we  observe  nume- 
rous fasciculi  of  muscular  fibres,  which  are 
named  inter-spinalis,  inter-transversalis,  and 
multifidus  spince.  These  might  be  considered 
a  seventh  layer ;  but  they  are  very  analogous 
to  the  small  muscles  just  described,  and  nearly 
on  the  same  plane. 

The  inter-spinales  are  short  bundles  of  fleshy 
fibres  placed  between  the  spinous  processes  of 
contiguous  vertebrae.  They  are  in  pairs  in  the 
neck,  where  the  spine  consists  of  two  laminae. 
Here  also  they  are  well  marked.  In  the  dorsal 
region  they  are  scarcely  visible,  and  in  the 
loins  they  are  not  easily  distinguished  from  an 
interspinal  ligament.  They  are  analogous  to 
the  recti  postici.  They  extend  the  spine. 

On  the  lips  of  the  spinous  processes  of  the 
neck  some  fibres  may  be  shown,  to  which  the 
name  supra-spinal  muscles  has  been  given. 
They  extend  farther  than  from  one  vertebra  to 
the  next. 

The  inter-transversales  are  similar  fibres, 
scarcely  to  be  demonstrated  except  in  the  neck, 
where  they  are  in  pairs,  corresponding  to  the 
divided  transverse  processes. 

The  multifidus  spines  consists  of  separate 
bundles  of  fibres,  extending  from  each  trans- 
verse process  obliquely  upwards  and  inwards 
to  the  spinous  process  of  the  vertebra  next  above, 
or  sometimes  to  the  second  above.  The  first 
bundle  runs  from  the  side  or  transverse  process 
of  the  sacrum  to  the  spine  of  the  last  lumbar 
vertebra ;  the  last  from  the  transverse  process 
of  the  third  cervical  to  the  spine  of  the  second. 
They  are  smaller  as  we  ascend,  and  are  not 
easily  separated  from  the  spinales  and  semi- 
spinales.  They  support  the  spine,  and  rotate 
one  vertebra  on  the  other  slightly. 

In  the  article  SPINE,  the  practical  utility  of  a 
knowledge  of  the  muscles  of  this  extensive 
region  will  be  demonstrated. 

For  the  BIBLIOGRAPHY  of  this  article  see  that 
of  ANATOMY  (INTRODUCTION). 

(Charles  Benson.) 


BILE.  Syn.  Gall.  (Gr.^oXTj;  Lat.  bills; 
Fr.  bile ;  Ger.  die  Guile ;  \\3\.jiele.j — This  im- 
portant secretion  has  been  laboriously  examined 
by  several  modern  chemists  of  eminence,  among 
whom  we  may  especially  enumerate  Thenard,* 
Berzelius,f  Tiedemann  and  Gmelin,J  and 
Frommherz  and  Gugert.§  Their  results,  how- 
ever, are  so  much  at  variance,  that  it  is  impos- 
sible to  draw  any  general  conclusions  from 
them  respecting  the  real  nature  and  chemical 
components  of  the  bile ;  these  discrepancies 
seem  partly  to  arise  from  the  extreme  facility 
with  which  chemical  agents  react  upon  this 
secretion,  so  that  many  of  the  supposed  educts 
or  component  parts  which  have  been  enume- 
rated, are  probably  products  of  the  different 
operations  to  which  it  has  been  submitted,  or 
at  all  events  modifications  of  its  true  proximate 
elements :  it  has  been  therefore  well  observed 
by  Berzelius,  that  our  present  chemical  know- 
ledge of  the  nature  of  bile  can  only  be  consi- 
dered as  a  foundation  for  the  more  extended 
and  satisfactory  researches  of  future  experimen- 
talists. We  shall  here  endeavour  to  select 
some  of  the  least  disputable  and  most  import- 
ant facts  respecting  the  chemical  properties  of 
the  bile,  remarking  at  the  outset  to  those  who 
may  be  inclined  to  repeat  the  experiments 
which  we  shall  cite,  that  the  indications  of  re- 
agents upon  different  specimens  of  bile  are  apt 
to  vary,  and  that  their  action  is  often  much 
modified  by  temperature,  quantity,  and  the 
mode  in  which  they  are  used. 

There  always  appears  to  be  mixed  with  bile 
a  variable  proportion  of  mucus,  probably  deri- 
ved from  the  gall-bladder  and  its  ducts,  and 
not,  therefore,  a  true  component  of  the  secre- 
tion :  this  gives  the  bile  its  viscidity,  and  often 
seems  in  some  way  to  modify  its  other  charac- 
ters: in  general,  however,  (ox-gall,)  it  is  a 
green  liquid,  varying  much  in  tint,  of  a  pecu- 
liar odour,  a  bitter  and  nauseous  taste,  and  a 
specific  gravity  fluctuating  between  1.020  and 
1 .030.  It  does  not  coagulate  when  heated,  and 
although  it  may  possibly  contain  albumen,  or 
something  very  like  it,  it  is  not  immediately  coa- 
gulated by  alcohol  or  by  dilute  acids.  The  rela- 
tive proportion  of  solid  matter  obtained  by  evapo- 
ration is  between  eight  and  ten  per  cent.  By 
means  of  acetic  acid,  the  mucus  which  is  mixed 
with  the  bile  may  to  a  great  extent  be  separated. 
In  the  mammalia,  generally,  the  bile  exhibits 
nearly  the  same  characters ;  and  in  birds  and 
fishes  its  components  seem  to  be  the  same,  but 
rather  more  dilute  in  the  former  and  more  con- 
centrated in  the  latter :  it  is  always  alcaline,from 
the  presence  of  soda,  apparently  in  the  same 
state  of  combination  as  it  exists  in  the  serum 
of  the  blood.  When  bile  is  evaporated  very  care- 
fully to  about  half  its  bulk,  and  alcohol  added, 
(in  the  proportion  of  about  four  parts  to  one  of 
the  evaporated  bile,)  a  coagulated  matter  is 
thrown  down,  which  has  some  of  the  proper- 

*  Thenard,  Memoires  d'Arcueil,  i. 
t  Lehrbuch    der  Thierchemie.     Dresden,  1831  ; 
and  Medico-Chirurgical  Transactions,  iii. 
$  Uber  die  Verdauung  (Essay  on  Digestion). 
§  Schweigger's  Journal,  v.  1. 


BILE. 


375 


ties  of  albumen;  yet  neither  solution  of  corro- 
sive sublimate,  nor  of  ferrocyanate  of  potassa, 
which  are  such  delicate  tests  of  that  proximate 
animal  principle  in  other  cases,  enables  us  to 
detect  it  in  the  original  bile.     When  alcohol  is 
added  to  bile  which  has  been  evaporated  nearly 
to   dryness,   it  acquires,  when  tillered   off,  a 
brownish  green  colour  and  bitter  taste ;  when 
evaporated,  it  leaves  a  residue  which  is  almost 
totally  soluble  in  water;  and  in  this  aqueous 
solution,  dilute  sulphuric  acid  slowly  throws 
down  a  grey  substance,  which  appears  to  be  a 
compound  of  the  acid  and  the  bitter  principle 
of  the  bile;    when  it  has  been  washed  with 
water  (in  which  it  is  not  soluble),  it  dissolves 
in  alcohol,  and  if  the  sulphuric  acid  be  then 
separated  from  it  by  carbonate  of  baryta  and 
nitration,  the  filtered  solution  leaves  on  evapo- 
ration   a    green,    transparent,    bitter  residue, 
which  appears  to  be  the  characteristic  princi- 
ple of  the  bile,  and  which  Berzelius  calls  Gal- 
lenstoff'.    As  thus  obtained,  it  is  not  quite  free 
from  foreign  matters,  and  ether  digested  upon 
it  takes  up  a  little  fatty  matter ;  indeed  when 
bile,  concentrated  by  evaporation,  is  agitated 
with  ether,  and  the  latter,  after  having  separated 
upon  the  surface,  is  poured  oft' and  evaporated, 
it  always   leaves  traces  of  a  fatty  substance, 
probably  identical  with  cholesterine.     The  pu- 
rified  bitter  residue,  to  which  we  have  just 
adverted,  is  apparently  the  picromel  of  Thenard; 
it  has  a  bitter,  pungent,  and  sweetish  taste,  is 
inflammable,  deliquescent,    soluble   in   water 
and  alcohol,  but  insoluble  in  ether ;  its  solu- 
tion is  precipitated  by  many  acids,  (not  by 
acetic  or  phosphoric,)  and  the  precipitate  is 
nearly  insoluble  in  water,  of  a  greenish  colour, 
resinous  appearance,  and  fusible  at  212°.     This 
precipitate  (consisting  of  picromel  combined 
with  the  acid  used  to  throw  it  down)  dissolves 
in  alcohol,  and  is  again  thrown  down  by  water : 
it  dissolves  in  solution  of  acetate  of  potash,  the 
alcali  of  which  combines  with  the  acid  of  the 
precipitate,  whilst  the  acetic  acid  unites  to  the 
picromel  to  form  a  soluble  acetate.     Picromel 
dissolves  in  weak  alcaline  solutions  apparently 
without  decomposition. 

It  will  be  seen  from  many  of  the  above  cha- 
racters, that  picromel  (by  which  we  mean  Ber- 
zelius's  Gallenstoff)  has  probably  been  mistaken 
for  albumen,  and  that  it  is  not  improbable  that 
the  only  true  albuminous  part  of  the  bile  may 
be  in  that  equivocal  state  which  is  often  called 
mucus,  and  which  is  especially  distinguished 
by  being  precipitable  by  acetic  acid.  Berze- 
lius has  suggested  an  analogy  between  picromel 
and  the  peculiar  saccharine  matter  which  is 
contained  in  liquorice-root;  and  in  many  re- 
spects their  chemical  properties  are  identical. 

In  the  preceding  statement,  drawn  princi- 
pally from  Berzelius,  we  have  endeavoured  to 
give  the  simplest  view  of  the  analysis  of  the 
bile ;  namely,  the  separation  of  its  muco-albu- 
mcn  by  acetic  acid  or  alcohol,  and  of  its  picromel, 
by  precipitation  with  acids  and  subsequent 
decomposition  of  the  precipitate  by  carbonated 
baryte  or  alcali;  its  saline  contents  appear 
closely  to  resemble  those  of  the  serum  of  the 
blood  ;  like  which  it  has  an  alcaline  reaction, 


due  to  soda.  We  have  also  selected  such  ex- 
periments, as,  with  us,  have  invariably  suc- 
ceeded :  the  following  results,  therefore,  of  the 
analysis  of  the  bile,  as  given  by  Berzelius,  will 
now  be  intelligible. 

Water    90.44 

Picromel,  (Gallenstoff,)  inclu- 
ding fat ,  .  8.00 

Mucus  of  the  gall-bladder    ..     0.30 
Extractive,  common  salt,  and 

lactate  of  soda 0.74 

Soda 0.41 

Phosphate  of  soda  and  lime  and 
traces  of  a  substance  insolu- 
ble in  alcohol  0.1 1 

100. 

The  details  of  the  other  analyses  of  the  bile 
as  given  by  the  authorities  to  which  we  have 
referred  above,  would  be  unintelligible  if 
abridged,  and  are  too  voluminous,  and  too  ex- 
clusively chemical,  to  be  inserted  here;  and 
moreover,  we  have  generally  failed  in  arriving 
at  satisfactory  conclusions  in  our  endeavours  at 
a  repetition  of  the  various  analytical  operations 
which  are  described;  we  must  therefore  rest 
satisfied  with  giving,  in  a  condensed  form,  a 
general  statement  of  their  results.  According 
to  Thenard,  human  bile  contains,  water  90.90  ; 
yellow  bitter  resin  3.73;  yellow  matter  gene- 
rally diffused  through  the  bile  (mucus  and  colour- 
ing matter?)  0.18  to  0.90 ;  albumen  3.82  ;  soda, 
by  which  the  resin  is  dissolved,  0.51;  phos- 
phate, sulphate,  and  muriate  of  soda,  phosphate 
of  lime,  and  oxide  of  iron,  0.41.  Tiedemann 
and  Gmelin  give  the  following  as  the  compo- 
nents of  human  bile:  1.  fat;  2.  brown  resin; 
3.  sweet  principle  of  bile;  4.  salivary  matter; 
5.  mucus;  6.  gall-brown  (colouring  matter?); 
7.  oleic  acid,  salts,  and  minute  quantities  of 
other  substances,  Frommherz  and  Gugert*  have 
arrived  at  yet  more  complicated  results:  namely, 
1.  fat ;  2.  resin ;  3.  sweet  principle;  4.  osma- 
zome;  5.  salivary  matter  (Speichelstoff);  6.  ca- 
seum;  7.  mucus;  8.  margaric  and  other  fatty 
acids,  with  phosphate,  muriate,  and  sulphate  of 
soda  and  potash ;  and  carbonate,  phosphate, 
and  sulphate  of  lime.  The  above,  and  other 
chemists,  have  published  analyses  of  bile,  taken 
after  death  in  various  diseases,  but  they  present 
nothing  very  important.  Tiedemann  and  Gme- 
lin's  elaborate  analysis  of  ox-gall  deserves  the 
perusal  of  all  chemists  concerned  in  such  in- 
quiries :  it  contains,  according  to  L.  Gmelin,f 
a  substance  not  to  be  found  in  any  other  bile, 
and  which  he  has  called  Taurin  or  GailentiKpa- 
ragin :  it  may  be  obtained  as  follows  : — add 
muriatic  acid  to  ox-gall  and  filter ;  after  a  few 
days  a  fatty  matter  appears,  which  is  separated 
by  filtration ;  the  filtered  liquid  is  evaporated 
to  a  small  bulk,  when  it  separates  into  two 
parts,  a  resinous  mass  and  a  sour  fluid  :  the 
latter,  upon  further  evaporation,  yields  more 
resinous  matter,  and  at  length  crystals  of  com- 

*  M.  Scbweigger's  Journal,  vol.  1.  p.  8. 
f  L.  Gmelin,  Handbuch  der  Thcoretischen  Cbe- 
mie,  ii.  1012.     Frankfurt,  1829. 


BLADDER,  NORMAL  ANATOMY, 


376 

mon  salt  and  taurin,  which  are  to  be  separated, 
and  the  latter  purified  a  second  by  crystalli- 
sation. Taurin,  when  purified,  is  in  prismatic 
crystals,  neither  acid  nor  alkaline,  not  altered 
by  exposure  to  air,  inodorous,  of  a  peculiar 
taste :  soluble  in  about  fifteen  parts  of  cold  wa- 
ter, and  nearly  insoluble  in  absolute  alcohol : 
it  is  fusible, and  not  decomposed  by  nitric  acid. 

In  concluding  this  subject,  we  must  again 
express  our  conviction  that  many  of  the  sup- 
posed proximate  components  of  bile  are  pro- 
ducts of  the  various  operations  and  re-agents  to 
which  it  has  been  submitted,  and  that  the  ana- 
lysis of  Berzelius,  which  is  the  simplest,  is 
probably  the  most  correct:  from  the  uncertain 
operation  of  various  precipitants  upon  bile,  and 
from  the  facility  with  which  the  results  vary, 
apparently  in  consequence  of  very  trifling  causes, 
there  seems  to  be  a  peculiar  tendency  in  its 
component  parts  to  undergo  hitherto  unex- 
plained modifications. 

BILIARY  CALCULI,  or  gull-stones. — These 
concretions  have  been  especially  examined  by 
Gren,  Thenard,  Fourcroy,  and  as  to  the  fatty 
matter  which  they  contain,  by  Chevreul.* 
Human  gall  -  stones  are,  for  the  most 
part,  composed  of  a  crystalline  aggregate  of  a 
species  of  adipocere,  or  as  it  has  been  termed 
by  Chevreul,  cholesterine,  (from  %o^»j,  bile,  and 
<rregeo$,  solid,)  with  more  or  less  colouring 
matter,  muco-albumen,  and  inspissated  bile; 
they  are  accordingly  of  various  colours  and 
textures,  but  generally  brittle  and  friable. 
Those  which  are  chiefly  cholesterine,  or  as  it 
should  more  properly  be  termed  cholestearine, 
are  white  and  crystalline,  and  lighter  than 
water;  the  others  are  more  tough,  coloured, 
and  dense ;  their  specific  gravities,  therefore, 
vary  from  0.803  to  1.06.  Their  chemical  ex- 
amination may  be  conducted  as  follows  :  they 
may  be  powdered,  and  digested  in  water  to 
separate  the  inspissated  bile :  then  boiled  in 
alcohol,  and  the  solution  filtered  whilst  hot; 
as  it  cools  it  deposits  the  cholesterine,  and 
often  retains  common  fat  and  its  acids  in  solu- 
tion. The  portion  which  resists  the  action  of 
alcohol  may  be  digested  in  a  weak  solution  of 
caustic  potash,  which  takes  up  colouring  matter 
and  muco-albumen :  the  solution,  supersatura- 
ted by  acetic  acid,  deposits  these,  and  the  co- 
louring matter  may  afterwards  be  removed  by 
alcohol.  Any  common  albumen  may  be  de- 
tected by  ferrocyanate  of  potash  added  to  the 
acetic  solution. 

Cholesterine  separates  in  white  pearly  scales 
from  its  hot  alcoholic  or  etherial  solution  during 
cooling;  it  fuses  at  about  280°,  and  when 
heated  to  about  400°,  it  sublimes :  in  the  open 
air  it  burns  like  wax.  Its  ultimate  components 
are  85  carbon,  12  hydrogen,  3  oxygen.  It  is 
the  most  carbonaceous  of  all  the  varieties  of  fat. 

The  gall-stones  of  the  ox  frequently  consist 
chiefly  of  the  yellow  colouring  matter  of  the 
bile,  which  is  occasionally  used  by  painters  on 
account  of  its  brightness  and  durability  :  it  is  in- 
soluble in  water  and  alcohol,  but  readily  solu- 
ble in  weak  solution  of  potash,  from  which  it 

*  Annales  de  Chimic,  xcv.  5. 


is  thrown  down  in  green  flocks  by  muriatic? 
acid :  nitric  acid  cautiously  dropped  into  a 
solution  of  this  colouring  matter  gives  it  various 
shades  of  green,  blue,  and  red. 

BlBLlOGKAFHY. — Bianchi,  Historia  hepatica,  2 
vol.  4to.  Genev,  1725.  Rcederer,  Experimenta  circa 
bilis  nat.  4to.  Argent.  1767.  Cadet,  Exper.  sur 
la  bile  ties  homines  et  des  animaux  :  Mem.  de 
1'Acad.  de  Paris,  1767.  Bvrdenave,  Analyse  de 
la  bile,  ibid,  (Savans  etrangers,  t.  vii.)  Madura, 
Experiments  upon  the  human  bile,  8vo.  Lond. 
1772.  Goldwitx,  Neue  Versuche  zu  ein  wahren 
Physiologic  der  Galle,  8vo,  Bamb,  1782.  Ploucquet, 
Exper.  circa  vim  bilis  chyliferam,  4to.  Tubing. 
1792.  Thenard,  Deux  mem.  sur  la  bile  :  Mem. 
d'Arcueil,  t.  i.  Sounders,  A  treatise  on  the  struc- 
ture, &c.  of  the  liver,  8vo.  Lond.  1793.  John, 
Chemische  Tab  lien :  Tableaux  chimiques,  4to. 
Paris,  1816.  Chevreul,  Note  SUT  la  presence  de 
cholesterine  dans  la  bile  de  rtiomme  ;  Journ.  de 
China.  Med.  t.  i.  and  Ann.  de  Chimie,  No,  xcv. 
Bracconnot,  Rcch.  sur  la  bile  :  Ann.  de  Phys.  et 
de  Chimie,  Oct.  1829.  Orfila,  Elem.  de  chimic, 
2  vol.  8vo.  Berzelius,  Traite  de  chimie  :  Raspail, 
Nouv.  systeme  de  chimie  organique,  8vo.  Paris, 
1833:  Anglice  a  Henderson,  8vo.  Lond.  1834. 
(W.  T.Erande.) 

BLADDER,  (in  anatomy.)  (Gr.  jev<rr«. 
Lat.  vesica,  vesic ula.  Fr.  vessie,  vesicule.  Germ. 
Blase.  Ital.  vescica). — This  term  is  employed 
to  denote  a  membranous  sac,  more  or  less 
complicated  in  its  structure,  with  one  or  more 
orifices,  and  destined  as  a  reservoir  for  parti- 
cular fluids.  We  have,  for  instance,  in  most 
animals  provided  with  a  liver,  a  gall-bladder 
or  reservoir  for  the  bile ;  in  fishes  we  have  a 
swimming-bladder,  vesica  natatorta;  and  in 
the  females  of  several  insects,  mollusca  and 
•  crustaceans,  a  bladder,  recently  described  by 
Audouin,  Milne  Edwards,  Des  Hayes,  and 
others,  the  function  of  which  is  to  receive, 
during  copulation,  the  prolific  fluid  from  the 
male,  and  which  has,  therefore,  been  called 
vesicule  copulatrice.  In  fine,  in  a  great  num- 
ber of  the  animals  provided  with  a  urinary  ap- 
paratus we  have  a  urinary  bladder,  vesica 
urinuria.  For  a  particular  description  of  the 
first  three  varieties  of  bladder  we  refer  to  the 
articles  LIVER,  PISCES,  and  INSECTA; — that 
of  the  urinary  bladder  forms  the  subject  of  the 
succeeding  article. 

( R.  B.  Todd.) 

BLADDER  OF  URINE  (normal  anato- 
my).— (Ky<7Tt?  oupo^o^o?,  vesica  urinaria. 
Germ.  Harnblase.  Commonly  known  as  the 
Bladder.)  The  urinary,  like  the  biliary  appa- 
ratus, consists  of  four  principal  organs,  each 
accomplishing  a  different  purpose,  yet  all  con- 
tributing to  the  same  end,  namely,  the  sepa- 
ration from  the  circulating  medium  of  a  consi- 
derable portion  of  aqueous  and  saline  matter : 
these  are,  first,  the  kidney  or  kidneys,  which 
are  the  principal,  indeed  the  sole  agents  in 
this  function ;  secondly,  the  ureters,  the  excre- 
tory ducts,  whose  office  it  is  to  convey  the 
fluid  secreted,  drop  by  drop,  as  fast  as  it  is 
formed,  which  is  by  a  slow  and  gradual  pro- 
cess, to,  thirdly,  the  urinary  bladder,  which 
serves  merely  as  a  temporary  receptacle  for  it ; 
and,  fourthly,  the  urethra,  or  terminating  ex- 


BLADDER,  NORMAL  ANATOMY. 


377 


cretory  tube,  whereby  this  fluid  is  wholly 
discharged  from  the  system. 

A  urinary  bladder  has  not  been  ascertained 
to  exist  in  any  of  the  invertebrate  division  of 
animals,  and  in  the  vertebrate  there  is  a  great 
diversity  with  respect  to  it :  thus  in  the  class 
Pisces,  this  organ  is  absent  in  all  the  osseous 
family,  in  most  of  whom,  however,  the  two 
ureters  unite  below,  and  form  a  slight  heart- 
shaped  dilatation  which  opens  externally  be- 
hind the  anus  in  common  with  the  sexual 
organs:  this  vesicle,  though  somewhat  analogous 
to,  cannot  be  considered  as  a  perfect  reservoir. 
In  most  of  the  cartilaginous  fishes  it  is  absent 
also,  as  in  the  ray  and  shark,  in  whom  the 
ureters  open  as  in  birds  into  a  cloaca,  or  reser- 
voir common  to  the  renal,  sexual,  and  intes- 
tinal discharges;  in  some,  however,  of  this 
family  it  is  present,  as  in  the  cyclopterus  or 
lump-fish,  the  lophius  piscatorius,  &c. ;  in  the 
latter  it  is  very  capacious,  and  its  coats  are  so 
thin  as  to  be  transparent;  it  receives  the  ureters 
anteriorly,  and  opens,  as  is  usual  in  fish,  behind 
the  anus,  in  common  with  the  genital  ducts. 

In  Reptilia,  the  bladder  is  present  in  some, 
as  the  Batrachia  and  Chelonia ;  it  is  absent  in  all 
the  Ophidia,  and  in  many  of  the  Sauria,  as 
the  crocodile,  the  gecko,  and  the  lizard ;  while 
again  it  exists  in  many  of  the  same  division,  as 
tin.'  iguana,  chameleon,  draco,  &c.  In  the 
Batrachia,  as  the  frog  and  the  toad,  it  is  situated 
in  front  of  the  rectum  or  cloaca,  into  which 
it  opens  ;  the  ureters  open  into  the  latter  poste- 
riorly, from  whence  the  urine  is  directed  into 
the  bladder  by  the  muscular  contraction  of  the 
cloaca  and  of  the  sphincters  of  the  anus.  In 
the  frog  its  cavity  is  large,  parietes  thin,  and 
its  fundus  divided  into  two  cornua.  In  the 
Chelonia,  as  the  tortoise,  it  is  very  large,  and 
the  ureters  open  into  the  urethra  anterior  to  its 
cervix,  the  urine  must  therefore  return  or  reas- 
cend  to  enter  the  bladder.  In  the  Ophidia  or 
the  Serpent  tribe,  each  ureter  dilates  inferiorly 
into  a  small  vesicle,  which  then  opens  into  the 
cloaca,  and  there  is  no  other  approximation  to 
a  bladder ;  in  such  of  the  Sauria  as  this  organ 
exists,  it  opens  into  the  cloaca. 

In  Aves  the  bladder  is  always  absent ;  in 
the  whole  of  this  extensive  class,  the  ureters 
open  into  the  cloaca,  and  the  urine,  which  is  so 
earthy  as  to  appear  almost  solid,  is  there  min- 
gled with  the  faeces,  in  common  with  which  it 
is  discharged  at  short  and  repeated  intervals. 
In  the  Ostrich  and  Cassowary  the  cloaca  is 
very  dilatable,  and  its  muscular  structure  is  so 
organized  as  to  be  enabled  to  retain  within  it, 
and  to  discharge  occasionally  a  considerable 
quantity  of  urine;  hence  in  these  animals  a 
vesica  urinaria  has  been  by  some  erroneously 
supposed  to  exist. 

In  all  mammalia  this  organ  exists,  and  in 
every  member  of  this  class  the  ureters  enter  it 
obliquely  at  a  little  distance  behind  the  cervix, 
with  the  exception  of  the  ornithoryncus  and 
monotrematous  animals  generally  ;  in  these  the 
ureters  open  into  the  urethra  a  little  beyond  or 
anterior  to  the  cervix  of  the  bladder,  so  that 
the  urine  must  return  or  ascend,  in  order  to 
enter  its  cavity;  this  curious  arrangement  is 


similar  to  that  adopted  in  the  chelonia,  and 
would  appear  to  indicate,  as  Cams  ingeniously 
suggests,  that  in  these  strangely  formed  animals, 
in  the  same  manner  as  in  reptiles  and  in  birds, 
the  allantois  (the  remains  of  the  urachus  of 
which  form  the  bladder  in  mammalia)  arises 
from  the  expansion  of  the  rectum  or  the  cloaca, 
whilst  in  other  quadrupeds  it  is  solely  connected 
to  the  genital  passages.  In  all  mammalia  this 
organ  presents  a  tolerably  uniform  appearance 
both  as  to  structure  and  shape,  but  great  diver- 
sity as  to  capacity  or  size ;  the  latter  appears  to 
be  in  an  inverse  ratio  to  its  muscularity  :  hence 
in  Carnivora,  the  bladder  being  more  muscular, 
appears  smaller  in  proportion  to  the  size  of  the 
animal  than  in  some  of  the  Herbivora,  where 
its  coats  are  thinner,  and  therefore  more  dila- 
table ;  in  others,  however,  of  the  latter  order, 
in  whom  it  is  very  muscular,  its  capacity  is 
inferior  to  that  of  some  even  of  the  carnivora  : 
in  the  Rodentia  it  is  muscular  and  small,  par- 
ticularly if  contrasted  with  the  genital  appa- 
ratus. In  quadrupeds  the  bladder  is  usually 
more  covered  by  the  peritoneum,  and  hence  it 
appears  more  loose  and  free  in  the  abdomen 
than  in  the  human  subject;  its  figure  is  usually 
rounded,  pyriform,  or  oval ;  and  it  may  be  re- 
marked (and  the  remark  will  even  apply  to  the 
human  child  and  embryo)  that  the  younger  the 
animal  the  more  elongated  is  the  bladder,  a 
fact  which  is  indicative  of  its  derivation  from, 
or  original  continuity  with  the  urachus  and 
allantois. 

THE  URINARY  BLADDER  IN  MAN  is  deeply 
seated  in  the  anterior  inferior  part  of  the  pel  vis  : 
it  is  composed  of  different  tissues,  membranous 
and  muscular,  both  calculated  to  yield  and 
to  expand  to  a  slightly  distending  force,  so  as 
to  form  a  recipient  reservoir,  while  the  latter  is 
fitted  by  its  contractile  power  to  obliterate  the 
cavity  of  the  organ,  and  forcibly  to  eject  its 
contents.  This  musculo-membranous  viscus 
demands  the  particular  attention  of  the  surgical 
anatomist,  not  merely  as  to  its  structure,  but 
as  regards  its  situation  and  connections,  as  it 
is  the  seat  of  many  very  severe  and  often  fatal 
morbid  affections,  several  of  which  admit  of  a 
perfect  cure,  and  most  of  considerable  relief, 
from  operation  and  from  various  kinds  of  local 
treatment,  the  safe  performance  and  judicious 
application  of  which  greatly  depend  on  a  cor- 
rect knowledge  of  the  structure  and  relations 
of  the  organ.  We  propose  first  to  consider 
the  form  and  structure  of  the  bladder  in  the 
normal  state,  and  afterwards  to  describe  its 
situation  and  connections. 

Shape. — The  figure  of  the  bladder  must 
vary  according  to  its  state  of  contraction  or 
distention,  in  reference  to  which  it  is  usual 
to  consider  it  under  three  conditions,  viz. 
the  empty  or  contracted,  the  full  or  ordina- 
rily distended,  and  the  over-distended.  Its 
figure  in  these  different  states  also  varies  ac- 
cording to  the  sex  and  age  of  the  individual, 
the  bladder  of  the  infant  differing  materially 
from  that  of  the  adult,  and  that  of  the  adult 
female  from  that  of  the  male ;  the  bladder  of 
the  embryo  also  differs  from  that  of  the  fully 
developed  foetus.  The  younger  the  animal,  the 


378 


more  does  its  form  resemble  that  of  inferior 
animals,  and  it  is  an  organ  very  fully  developed 
in  the  young  of  all  animals  who  possess  it. 
This  organ,  in  the  adult  male,  when  empty  or 
contracted,  is  a  flattened  triangle,  the  transverse 
and  vertical  axes  being  considerably  greater 
than  the  antero-posterior  one;  in  this  con- 
dition the  bladder  is  buried  deep  in  the  pelvis, 
behind  and  partly  below  the  symphysis  pubis ; 
the  base  of  the  triangle  is  in  front  of  but  not 
very  closely  applied  to  the  rectum,  unless  the 
cavity  of  the  latter  be  fully  distended.  When 
the  bladder  is  expanded  in  tht?  adult  male  to 
that  moderate  degree  which  in  perfect  health 
usually  excites  a  slight  feeling  or  desire  to  void 
the  urine,  and  when  the  quantity  accumulated 
may  amount  to  half  a  pint  or  upwards,  its 
figure  is  then  somewhat  oval,  its  vertical  axis 
being  considerably  greater  than  either  the 
transverse  or  the  antero-posterior,  the  two  latter 
being  then  nearly  equal.  The  larger  end  of 
this  ovoid  sac  rests  inieriorly  and  posteriorly 
on  the  rectum,  and  is  of  an  irregular  form  ;  the 
smaller  end,  which  is  more  regularly  sphe- 
roidal, is  directed  upwards  towards  the  abdo- 
men, and  somewhat  forwards,  and  occasionally 
also  a  little  towards  the  left  side.  When  the 
bladder  is  over-distended  from  any  cause,  it 
becomes  considerably  increased  in  every  dia- 
meter; it  first  expands  in  its  lower  and  middle 
portions,  until  the  pelvic  parietes  resist; 
it  then  enlarges  superiorly  to  an  indefinite 
degree,  and  at  the  same  time  the  whole  organ 
rotates  a  little  forwards  by  its  superior,  and  a 
little  backwards  by  its  inferior  fundus.  Its 
figure  in  this  over-distended  condition  is  not 
merely  enlarged,  but  it  also  presents  a  totally 
different,  or  rather  a  reversed  shape :  the  larger 
extremity  of  the  oval  is  now  superior,  occu- 
pying the  hypogastric  region,  which  it  ren- 
ders prominent  and  tense  in  a  degree  propor- 
tioned to  its  distension.  These  observations  as 
to  the  form  of  the  bladder  will  not  apply  in 
every  instance,  as  occasionally  this  viscus  pre- 
sents irregularities  both  in  size  and  shape,  as 
well  as  in  the  density  and  delicacy  of  its  tunics. 
The  bladder  in  the  female  child  does  not  differ 
from  that  of  the  male  of  the  same  age,  but  in 
the  adult  of  each  sex  it  presents  peculiarities. 
In  the  contracted  state  it  is  nearly  similar  in 
each,  only  somewhat  flatter  in  the  female. 
When  distended,  in  the  latter  it  presents  a  more 
triangular  form,  the  sides  somewhat  rounded, 
than  it  does  in  the  male,  where  the  ovoid  form 
prevails ;  in  the  female  its  lower  fundus  admits 
of  greater  lateral  extension  in  conformity  with 
the  shape  of  the  pelvis,  and  its  transverse  axis 
is  longer  in  proportion  than  in  the  male ;  hence 
it  assumes  the  triangular  more  than  the  oval 
figure.  This  character  is  more  remarkable  in 
the  female  who  has  borne  children  than  in  the 
virgin;  in  the  former  the  bladder,  when  dis- 
tended, appears  to  exhibit  the  effects  of  the 
pressure  of  the  uterus  posteriorly,  and  of  the 
pubes  anteriorly,  being  flattened  in  each  of 
these  aspects :  in  some  instances  it  resembles  a 
small  barrel  placed  tranversely. 

In  the  foetus  and  infant  of  a  year  old  the 
bladder  in  figure  more  resembles  that  of  a  qua- 


BLADDER,  NORMAL  ANATOMY. 


druped;  when  distended,  it  is  pyriform,' like  a 
bottle  or  a  flask  reversed,  the  larger  end,  or  the 
superior  fundus  being  in  the  abdomen,  and 
the  smaller  extremity  tapering  into  the  urethra. 
This  is  the  only  portion  in  the  pelvis ;  at  this 
age  its  vertical  axis  greatly  exceeds  its  other 
diameters,  and  even  when  empty  the  greater 
portion  of  it  is  in  the  abdomen.  As  the  child 
increases  in  years  and  size,  its  pelvis  expands, 
the  bladder  gradually  descends  into  this  region, 
and  in  the  same  proportion  its  lower  fundus 
enlarges,  so  that  at  about  six  or  seven  years  of 
age  it  presents  a  more  oval  form,  both  extremi- 
ties being  nearly  equal,  and  very  little  of  it 
rising  above  the  pubis,  unless  when  distended. 
From  this  period  it  continues  to  acquire  gra- 
dually the  adult  figure;  that  is,  its  inferior 
fundus  and  body  enlarge,  while  the  superior  re- 
mains stationary ;  hence  it  becomes  shorter  in  its 
proportions,  and  broader  below,  so  as  to  assume 
the  triangular  shape  when  empty,  and  the  ovoid 
when  distended.  About  two  months  before  birth 
the  bladder  is  very  much  elongated,  its  upper 
extremity  being  somewhat  pointed,  and  ap- 
proaching the  umbilicus  in  the  direction  of  the 
urachus.  When  distended,  it  presents  some- 
what the  appearance  of  a  cylinder  contracted 
at  each  extremity.  Soon  after  birth  the  upper 
fundus  becomes  rounder,  and  then  it  acquires 
the  pyriform  figure,  which  in  the  course  of  a 
few  years  undergoes  the  gradual  alterations  that 
have  been  already  noticed. 

The  capacity  of  the  bladder  in  the  adult 
cannot  be  accurately  ascertained,  as  it  varies 
from  a  number  of  circumstances,  such  as  age 
and  sex,  health  and  disease:  thus  irritation 
general  or  local,  ischuria  renalis,  cholera,  &c., 
will  cause  it  to  contract,  while  retention  of 
urine,  paralysis,  fever,  &c.,  will  allow  it  to 
enlarge.  Custom  or  habit  will  also  affect  it, 
likewise  the  position  of  the  body,  pregnancy, 
the  nature  or  peculiar  quality  of  diet,  the  tem- 
perament of  the  individual,  the  temperature  of 
the  atmosphere,  the  state  of  society,  &c.  In 
the  same  individual  it  will  at  one  time  contract 
so  as  to  retain  only  a  few  drops,  and  at  another 
it  will  dilate  so  as  to  contain  one,  two,  and 
even  three  pints.  Generally  it  is  more  capa- 
cious in  women,  particularly  in  those  who  have 
borne  children,  than  in  men. 

In  children  the  bladder,  although  very  dis- 
tensible under  certain  circumstances,  is  usually 
less  capacious  in  proportion  than  in  the  adult 
or  old,  probably  because  it  is  more  muscular 
and  irritable;  and  hence,  too,  the  more  fre- 
quent desire  to  contract  and  empty  its  contents. 

When  the  bladder  is  moderately  distended, 
anatomists  and  pathologists  have  been  in  the 
custom  of  dividing  it  into  four  regions  for  the 
purpose  of  more  accurate  description  ;  viz.,  the 
superior  part  or  the  upper  fundus,  the  middle 
part  or  body,  the  inferior  part  or  the  lower 
fundus,  and  the  cervix  or  neck.  This  arrange- 
ment is  not  very  correct,  for  it  can  only  apply 
to  this  organ  when  distended ;  the  term  su- 
perior fundus  also  is  obviously  objectionable, 
and  was  probably  derived  from  examining  this 
viscus  in  other  animals,  or  in  the  human  foetus 
where  the  lower  fundus  does  not  exist ;  neither 


BLADDER,  NORMAL  ANATOMY. 


379 


can  any  exact  distinction,  or  even  an  approxima- 
tion to  such,  be  made  between  these  several 
compartments.  A.  more  accurate  knowledge  of 
this  organ  may  be  obtained  by  examining  both 
internally  and  externally  its  several  aspects, 
which  are  six  in  number,  and  which  may  be 
regarded  as  distinct  regions ;  viz.,  an  anterior 
and  posterior,  two  lateral,  and  a  superior  and 
inferior.  We  shall  examine  each  of  these  ex- 
ternally, and  defer  any  remarks  on  their  in- 
ternal aspect  until  we  come  to  speak  of  the 
lining  membrane  or  the  mucous  coat  of  the 
bladder. 

The  anterior  region)  in  consequence  of  the 
obliquity  of  the  pelvis,  looks  also  downwards. 
When  the  bladder  is  contracted,  this  region  is 
behind  and  in  contact  (cellular  tissue  only  in- 
tervening) with  the  lower  half  or  three  fourths 
of  the  symphysis  pubis,  and  with  the  pubic  and 
triangular  or  interosseous  ligaments ;  when  dis- 
tended, it  rises  above  the  bone,  and  is  connected 
by  an  abundance  of  cellular  and  adipose  tissue 
to  the  lower  portion  of  the  recti  and  transversi 
muscles ;  and  as  no  peritoneum  is  there  inter- 
posed, this  part  can  be  punctured  with  safety 
during  life.  At  the  lower  border  of  this  region 
is  the  neck  of  the  bladder,  the  upper  surface  of 
which  is  firmly  attached  to  the  lower  edge  of 
the  symphysis  pubis  by  two  horizontally  placed 
fibrous  cords,  which  are  named  the  anterior 
ligaments  of  the  bladder,  and  which  will  be 
more  particularly  noticed  presently.  Between 
and  beneath  these,  some  veins  also  run  upon 
this  surface  of  the  bladder.  The  whole  of  this 
region  is  deprived  of  any  peritoneal  or  serous 
covering. 

The  posterior  region  has  an  aspect  upwards 
also;  it  is  smooth  and  covered  throughout  with 
peritoneum.  When  the  bladder  is  contracted, 
this  small  region  in  the  male  pelvis  is  in  con- 
tact with  the  fore-part  of  the  rectum,  or  with 
such  of  the  floating  abdominal  viscera  as  may 
chance  to  intervene;  in  the  female  with  the 
fore-part  of  the  uterus.  When  this  region  is 
distended,  it  presents  a  broad  smooth  convex 
surfage,  which  presses  more  against  the  rectum 
and  supports  the  convolutions  of  the  small  in- 
testines. 

The  lateral  regions,  when  the  bladder  is 
contracted,  are  little  more  than  margins  or 
edges,  and  present  nothing  worthy  of  notice ; 
but  when  distended,  each  becomes  a  broad 
surface,  somewhat  triangular,  the  base  below 
and  the  apex  above,  the  posterior  portion,  nearly 
the  half,  is  covered  by  peritoneum,  the  anterior 
portion  is  connected  by  cellular  tissue  to  the 
parietes  of  the  pelvis :  the  obliterated  umbilical 
artery  ascends  along  its  superior  posterior  por- 
tion, and  the  vas  deferens,  which  crosses  to  the 
inside  of  the  latter,  runs  along  this  region  in  an 
oblique  direction  downwards  and  backwards, 
and  marks  the  anterior  limit  of  the  peritoneum. 
From  this  region  the  broad  lateral  fold  of  this 
membrane  extends  to  the  iliac  fossa,  and  at  its 
inferior  border  is  that  reflection  of  the  vesical 
fascia  which  is  named  the  true  lateral  ligament 
of  the  bladder. 

The  superior  region,  by  some  called  the 
superior  fundus,  is,  when  the  bladder  is  empty, 


little  more  than  a  point  prolonged  into  the 
urachus;  but  when  distended,  it  presents  its 
large  and  convex  surface  upwards  and  forwards ; 
to  it  is  attached  the  superior  ligament  of  the 
bladder,  which  consists  of  three  fibrous  cords, 
the  urachus  and  the  obliterated  umbilical  arte- 
ries ;  behind  these  this  region  is  covered  by 
peritoneum,  but  anterior  to  them  it  is  not. 
The  former  portion  is  in  contact  with  the  con- 
volutions of  the  small  intestines,  the  latter  with 
the  recti  muscles. 

The  inferior  region,  or  the  inferior  fundus, 
or  the  base  of  some  authors,  always  exists 
as  a  distinct  surface,  whether  this  organ  be 
contracted  or  distended,  but  of  course  larger  in 
the  latter  condition.  It  is  rather  more  exten- 
size  in  a  transverse  direction  than  from  before 
backwards,  and  is  larger  and  more  distinct  in 
the  male  than  in  the  female :  its  lateral  por- 
tions in  each  sex  are  in  contact  with  the  leva- 
tores  ani  muscles,  and  correspond  to  the  spaces 
between  the  anus  and  the  tuberosities  of  the 
ischium.  In  the  female  its  middle  portion  is 
in  contact  with  the  vagina,  in  the  male  with  the 
rectum  in  the  middle  line,  and  with  the  vasa 
deferentia  and  vesiculse  seminales  on  either  side; 
to  the  latter  it  is  closely  connected.  The  cel- 
lular and  adipose  tissue  on  and  around  this 
region  in  the  adult  is  very  abundant,  and  con- 
tains numerous  veins.  This  region  is  covered 
posteriorly  by  peritoneum,  which  extends  to  a 
transverse  line  connecting  the  centre  of  each 
vesicula  seminalis.  This  line  corresponds  to 
the  convexity  of  the  cul-de-sac  formed  by  the 
reflection  of  this  membrane  from  the  bladder  to 
the  rectum.  In  front  of  this  line  this  region 
is  covered  in  the  middle  only  by  a  fascia  and 
by  some  cellular  tissue  as  far  as  the  base  of  the 
prostate  gland,  which  extends  for  some  dis- 
tance along  its  anterior  portion,  and  on  either 
side  are  the  vasa  deferentia  and  the  anterior 
terminations  of  the  vesiculae  seminales.  When 
the  bladder  is  distended  in  the  adult,  this  surface 
is  enlarged,  not  only  in  superficial  extent,  but  it 
also  swells  backwards  and  downwards  towards 
the  rectum,  and  even  presses  against  and  into 
that  intestine,  so  as  in  some  rare  cases  to  admit 
of  being  felt  by  the  finger  introduced  per  anurcu 
To  this  portion  the  name  of  *bas  fond'  is  com- 
monly applied.  In  the  adult  this  bas  fond,  that 
is,  the  posterior  part  of  this  region,  is  the  lowest 
portion  of  the  bladder,  and  hence  cannot  be 
evacuated  except  by  the  contraction  of  the 
organ  or  by  surrounding  pressure.  In  man,  in 
advanced  life,  it  is  often  found  dilated  into  a 
sort  of  pouch,  which  is  behind  and  quite  below 
the  level  of  the  anterior  part  of  this  region,  as 
well  as  of  the  neck  of  the  bladder,  forming  in 
some  instances  of  debility  a  sort  of  permanent 
reservoir,  and  one  in  which  calculi  are  not  un- 
frequently  contained.  In  the  fcetus  this  pouch 
or  fundus  does  not  at  all  exist,  the  cervix  or  the 
urethral  opening  being  then  the  most  depend- 
ing part,  which  circumstance  offers  another 
reason  for  the  power  of  retention  of  urine  being 
less  at  that  age  than  at  a  later  period  of  life.  Some 
writers  limit  the  inferior  region  to  so  much  of 
this  aspect  of  the  bladder  as  is  uncovered  by 
peritoneum,  and  therefore  consider  the  posterior 


380 


part  of  it  as  appertaining  to  the  posterior  region. 
Anatomically  we  consider  this  incorrect,  as  the 
vesicuta  seminales  are  acknowledged  by  all  to 
be  situated  on  the  inferior  region,  and  the  cul- 
de-sac  of  the  peritoneum  certainly  descends 
between  these  bodies  to  within  nearly  one-half 
or  three-fourths  of  an  inch  from  the  prostate 
gland.  In  a  practical  point  of  view  it  is  most 
essential  to  keep  this  in  mind,  because  in  the 
operation  of  recto- vesical  paracentesis  this  mem- 
brane is  endangered,  and  would  certainly  be 
perforated  if  the  trochar  were  passed  through 
the  posterior  portion  of  this  region.  The  sur- 
face of  the  bladder  which  can  be  opened  from  the 
rectum  in  that  operation  is  comparatively  small; 
it  is  of  a  triangular  form,  nearly  equilateral, 
situated  on  the  anterior  part  of  this  region.  The 
base  is  behind  marked  by  the  convex  border  of 
the  peritoneal  cul-de-sac  :  the  apex  is  at  the 
notch  in  the  base  of  the  prostate  gland,  and  the 
sides  are  the  vasa  deferentia  and  vesiculae 
seminales.  While  all  these  parts  are  in  situ, 
this  space  is  but  small ;  when,  however,  the 
bladder  has  been  removed  from  the  subject, 
distended,  and  dissected,  this  space  appears 
much  more  ample,  because  the  peritoneum 
recedes  from  it  in  proportion  as  the  attach- 
ments of  the  former  have  been  loosened. 

The  bladder  presents  to  our  notice  three 
diameters,  viz.  the  transverse,  antero-posterior, 
and  the  vertical ;  the  latter  is  also  called  its 
axis.  In  the  contracted  state  the  antero-pos- 
terior can  scarcely  be  considered  as  existing ; 
but  when  distended,  this  and  the  transverse 
diameters  are  nearly  equal.  In  all  states,  at 
least  in  the  male,  the  vertical  diameter  or  axis 
is  the  longest ;  this  line  leads  in  the  adult  from 
the  centre  of  the  upper  region  to  that  of  the 
lower  region  or  fundus  :  in  the  foetus  and  infant 
it  leads  from  the  urachus  to  the  orifice  of  the 
urethra;  if  this  line  be  contrasted  with  the 
axis  of  the  trunk  or  abdomen,  and  with  that 
of  the  pelvis,  it  will  be  found  to  correspond 
very  nearly  with  the  direction  of  the  latter,  and 
to  pass  very  obliquely  with  respect  to  the 
former.  The  axis  of  the  trunk  may  be  regarded 
as  nearly  a  vertical  line,  descending  through  the 
thorax  and  abdomen  to  the  pubis,  whereas  the 
axis  of  the  pelvis,  or  rather  of  its  superior 
orifice,  will  pass  obliquely  downwards  and 
backwards,  and  if  produced  at  either  end,  it 
will  pierce  the  recti  muscles  between  the  um- 
bilicus and  pubis  anteriorly,  arid  the  lower  end 
of  the  sacrum  posteriorly.  The  vertical  axis 
of  the  bladder  in  the  adult  is  on  a  lower  plane, 
but  nearly  parallel  to  that  line  ;  in  the  foetus  it 
is  more  parallel  to  that  of  the  trunk,  the  blad- 
der at  that  age  being  placed  more  in  the  ab- 
domen, and  in  a  more  vertical  direction  than 
in  the  adult. 

The  bladder  is  composed  of  several  mem- 
branous laminae,  called  coats  or  tunics  :  these 
are  essentially  three  in  number,  a  serous,  a 
muscular,  and  a  mucous.  They  are  connected 
together  by  cellular  tissue,  the  laminae  of  which 
being  two  in  number  are  also  considered  coats  ; 
so  that  the  whole  number  of  tunics  is  stated 
by  most  writers  as  five.  First,  the  serous  or 
peritoneal  is  but  a  partial  coat ;  it  covers  those 


BLADDER,  NORMAL  ANATOMY. 


portions  only  which  come  in  contact  with  some 
of  the  abdominal  or  pelvic  viscera,  namely,  all 
the  posterior  region,  and  the  posterior  portions 
of  the  lateral,  and  of  the  superior  and  inferior 
regions ;  consequently  it  is  deficient  on  all 
the  anterior  region,  and  on  the  anterior  part  of 
the  superior,  and  of  the  lateral  and  inferior 
regions.  The  course  of  the  vasa  deferentia 
marks  the  extent  or  the  limits  of  this  mem- 
brane on  the  bladder;  all  that  portion  which  is 
behind  and  between  these  tubes  is  covered  by 
it,  except  the  small  triangular  area  already 
noticed  on  the  inferior  region;  all  that  which  is 
anterior  to  these  vessels  is  uncovered  by  this 
membrane.  The  peritoneum  arrives  at  this 
viscus  from  the  fore-part  of  the  rectum  in  the 
male,  and  from  that  of  the  uterus  in  the  female, 
and  is  continued  from  its  lateral  regions  to  the 
iliac  fossae,  and  from  its  superior  fundus  to  the 
inside  of  the  recti  muscles.  This  membrane  is 
not  very  closely  attached  to  the  subjacent 
coat ;  it  can  be  easily  separated  from  it ;  it  is 
much  stronger  and  more  elastic  on  this  organ 
than  on  any  of  the  chylopoietic  viscera.  When 
the  bladder  is  distended,  there  is  more  in  pro- 
portion covered  by  peritoneum  than  when  it  is 
contracted.  The  female  bladder  has  more  of  the 
peritoneum  on  its  upper  fundus,  and  less  on  its 
lower  fundus  than  the  male  bladder,  and  in  the 
foetus  and  infant  it  is  still  more  extensively 
covered  by  this  membrane,  which  then  extends 
over  the  whole  of  the  upper  region  and  over  a 
small  portion  of  the  anterior.  As  the  peritoneum 
passes  from  the  sides  of  the  bladder  to  the 
iliac  fossae,  it  forms  folds,  improperly  called  the 
lateral  ligaments,  and  in  passing  from  the  back 
of  the  bladder  to  the  rectum  or  uterus,  a  similar 
fold  on  each  side,  called  the  posterior  ligaments 
of  the  bladder.  Between  these  the  cul-de-sac 
of  the  peritoneum  descends ;  this  in  the  male 
subject  is  the  lowest  portion  of  the  peritoneal 
cavity,  it  extends  to  within  about  three  inches 
and  a  half  of  the  anus  :  in  ascites  it  has  been 
known  to  be  somewhat  lower,  and  has  even 
been  tapped  in  this  situation  from  the  rectum. 

2dly.  The  external  or  first  cellular  coat  con- 
nects the  serous  to  the  muscular  tissue ;  it  also 
covers  those  regions  of  the  bladder  where  the 
serous  membrane  is  deficient.  In  the  lateral 
regions  it  is  more  distinct  and  thick,  and  is 
particularly  abundant  anteriorly  between  it  and 
the  pubes,  where  it  is  also  very  lax,  to  allow 
this  organ  when  distended  to  move  freely  as  it 
rises  out  of  the  pelvis  into  the  abdomen,  it 
contains  some  but  not  much  adipose  matter ; 
towards  the  inferior  and  lateral  parts  it  con- 
tains many  bloodvessels,  chiefly  venous,  and  a 
great  number  of  nerves,  which  can  be  distinctly 
traced  from  thence  in  all  directions  over  the 
bladder.  Towards  the  vesiculae  it  is  dense  and 
white,  and  supports  a  number  of  veins;  this 
coat  is  strong,  resisting,  and  elastic;  it  binds 
together,  supports,  and  assists  the  muscular 
fibres. 

The  third  coat  of  the  bladder  is  the  muscular : 
this  is  composed  of  fasciculi  running  in  dif- 
ferent directions,  and  which,  though  they  appear 
pale  and  feeble  when  contrasted  with  the  volun- 
tary muscles,  are  yet  much  stronger  and  redder 


BLADDER,  NORMAL  ANATOMY. 


than  those  in  the  corresponding  coat  in  most 
of  the  other  hollow  viscera,  being  intermediate 
in  these  respects  to  those  of  the  stomach  and 
oesophagus  ;  this  tunic,  however,  presents  great 
diversity  as  to  colour  and  density  in  different 
individuals.  In  the  contracted  state  of  the 
bladder,  it  of  course  appears  more  dense  than 
in  the  distended  ;  in  the  latter,  but  particularly 
in  the  over-distended  state,  it  appears  thin  and 
imperfect  in  some  places,  in  consequence  of 
the  fasciculi  being  separated  from  each  other. 
In  the  young,  cateris  puribus,  it  is  stronger 
than  in  the  old,  and  in  the  female  than  in  the 
male  ;  but  long-continued  irritation  at  any  age 
and  in  either  sex  has  the  effect  of  thickening  it, 
as  also  any  disease  which  causes  obstruction  to 
the  flow  of  urine.  If  the  bladder  be  removed 
from  the  body,  slightly  distended  and  sub- 
jected to  maceration  for  a  few  hours,  this  tunic 
will  admit  of  more  distinct  examination  ;  its 
fibres  will  then  be  seen  to  take  such  different 
directions  as  to  admit  of  a  tolerably  easy, 
though  not  a  perfectly  natural  separation  into 
distinct  laminae,  the  fibres  in  the  first  or  super- 
ficial of  which  have  a  longitudinal  course  ;  be- 
neath this  is  a  second  stratum,  whose  fibres 
are  transverse  or  circular;  and  in  some  situa- 
tions even  a  third  lamina  can  be  distinctly 
seen,  the  fibres  of  which  are  by  some  des- 
cribed under  the  name  of  oblique,  but  the 
term  reticular  would  appear  more  correct :  in 
general  these  three  laminae  can  be  made  dis- 
tinct, particularly  on  the  anterior  part  of  the 
bladder.  The  first  or  longitudinal  lamina  con- 
sists of  the  longest,  strongest,  and  most  nu- 
merous fasciculi ;  many  of  these  are  connected 
superiorly  to  the  urachus,  thence  they  descend 
principally  on  the  fore  and  back  part  of  the 
bladder,  a  few  only  along  the  sides ;  inferiorly 
they  terminate  about  the  neck.  These  fibres  are 
very  parallel,  and  much  stronger  on  the  an- 
terior and  posterior  aspects  than  upon  the  sides, 
where  they  run  more  obliquely  or  irregularly, 
and  decussate  with  one  another.  The  inferior 
attachment  of  these  fibres  in  the  male  subject 
may  be  ascertained  by  careful  dissection  to  be 
as  follows : — those  on  the  fore  part  of  the  bladder 
are  connected  chiefly  to  the  anterior  ligaments, 
or  to  the  reflections  of  the  fascia  from  the  pubis 
on  this  organ  ;  these  appear  as  shining  and  dis- 
tinct as  tendons,  and  have  been  by  some  con- 
sidered as  such  to  these  muscular  bands.  Above 
this  insertion  these  longitudinal  fibres  appear 
very  numerous,  and  those  on  the  right  and 
left  of  the  median  line  distinctly  decussate  or 
interlace.  Several  here  also  take  a  transverse  or 
an  arched  or  semicircular  course;  some  of  these 
are  very  distinct  and  are  inserted  laterally; 
they  must  serve  to  strengthen  and  to  bind 
down  the  longitudinal  fasciculi.  The  latter 
in  this  situation  can  be  divided  into  layers, 
the  superficial  of  which  only  are  inserted, 
as  has  been  described,  into  the  anterior 
ligaments  of  the  bladder,  and  through  these 
into  the  pubis.  The  deeper  set  are  inserted, 
some  into  the  dense  cellular  tissue  about  the 
upper  surface  of  the  prostate,  and  some  pass 
deeper,  and  intermingle  with  that  circular  mus- 
culo-cellular  tissue  which  surrounds  the  cervix, 


381 

and  which  constitutes  the  true  sphincter.  Some 
of  those  longitudinal  fibres,  particularly  more 
laterally,  pass  so  deep  in  this  situation  as  to 
be  very  distinctly  seen,  when  the  bladder  is 
opened,  through  the  mucous  lining  of  the  orifice 
of  the  urethra.  This  disposition  of  the  longitu- 
dinal fibres  we  consider  as  important,  as  it  must 
enable  them  during  their  contraction  to  draw 
out  or  expand  the  sphincter,  so  as  to  allow  of 
the  escape  of  the  urine.  Laterally  these  longi- 
tudinal fibres  are  attached,  a  few  of  them  to 
the  margin  of  the  prostate,  while  others  expand 
over  the  lateral  lobes  of  this  gland,  and  are  in- 
serted into  the  fascia  which  covers  it.  Poste- 
riorly these  fibres  are  very  distinct,  particularly 
near  the  inferior  surface  of  the  bladder  between 
the  two  ureters ;  to  these  last-named  tubes  seve- 
ral of  these  fibres  are  connected  :  some  ascend 
upon  them  in  arches  concave  upwards ;  these 
we  have  traced  several  inches  along  the  ureters  ; 
while  others  descend  in  the  same  course  with 
them,  and  are  inserted  into  the  trigone  of  the 
bladder.  The  longitudinal  fibres  collect  into  a. 
strong  flat  band  between  and  beneath  the  two 
vesiculee,  over  which  however  no  fibres  pass 
as  they  do  over  the  prostate,  which  circum- 
stance clearly  separates  these  vesicles  from, 
while  the  contrary  disposition  rather  connects 
the  prostate  with,  the  urinary  excretion.  This 
band  of  fibres  can  be  followed  near  to  the  base 
of  the  prostate ;  some  of  its  fibres  are  then  in- 
serted into  the  submucous  fibrous  tissue  in  this 
situation,  others  into  the  base  of  the  gland  itself; 
and  very  generally  one  long  delicate  but  distinct 
band  enters  the  notch  in  the  base  of  the  gland, 
passes  beneath  the  uvula  and  middle  lobe  of 
the  prostate,  into  which  it  is  sometimes  insert- 
ed, but  it  can  frequently  be  traced  nearly  an 
inch  further  forward  to  be  inserted  by  a  delicate 
tendon  beneath  the  seminal  caruncle  or  the 
verumontanum,  which  is  partially  covered  over 
by  a  fold  of  mucous  membrane  or  by  a  sort  of 
prepuce.  The  effect  of  this  band  of  the  longitu- 
dinal fibres  must  be  to  depress  the  uvula,  and 
thus  to  open  the  orifice  of  the  urethra,  and  also 
to  depress  and  to  draw  the  seminal  caruncle  (a 
sort  of  organized  glans)  downwards  and  back- 
wards within  the  prepuce  or  sinus  pocularis, 
which  covers  it,  and  thus  protects  it  from  the 
irritation  of  the  urine.  In  the  female  the  lon- 
gitudinal fibres  are  inserted  anteriorly  and  late- 
rally into  the  cellular,  glandular,  and  vascular 
tissue  which  surrounds  the  neck  of  the  bladder, 
and  posteriorly  into  a  more  dense  tissue  which 
connects  the  urethra  to  the  vagina;  some  fibres 
also  pass  in  deep,  as  in  the  male,  to  be  attached 
to  the  sphincter.  This  muscular  lamina  is  de- 
scribed by  the  older  authors  as  a  distinct  mus- 
cle, the  '  detrusor  uriruej  arising  from  and 
around  the  urachus  by  numerous  fibres,  which 
thence  descend  and  expand  over  the  whole 
surface,  and  again  concentrate  towards  the  neck 
of  the  bladder  to  be  inserted  by  one  or  two 
tendons  into  the  ossa  pubis.  This  account, 
however,  is  by  no  means  perfectly  correct ;  for 
on  attentively  examining  this  muscular  lamina, 
we  frequently  find  strong  transverse  fasciculi 
crossing  superficially  to  the  longitudinal  fibres, 
most  frequently  on  the  anterior  region,  but  also 


382 


BLADDER,  NORMAL  ANATOMY. 


near  the  neck.  Occasionally  some  of  the  longi- 
tudinal fibres  alter  their  direction  gradually  or 
abruptly,  as  may  be  particularly  noticed  about 
the  ureters  and  also  on  the  lateral  regions. 
Great  diversity  exists  as  to  the  arrangement  of 
this  tunic  in  the  lower  animals :  thus  in  the 
dog  this  plane  consists  of  strong  and  regularly 
parallel  fibres,  whereas  in  the  ox  they  assume  a 
reticular  and  irregular  course  :  in  man  they  re- 
semble the  arrangement  of  the  carnivorous  more 
than  that  of  the  graminivorous  animals.  This 
tunic  must  have  the  effect  of  compressing  the 
bladder  towards  the  ossa  pubis,  and  of  course 
urging  the  contents  of  the  cavity  in  that  direc- 
tion, while  at  the  same  time  some  of  its  fibres 
will  expand  the  orifice  of  the  urethra  by  draw- 
ing out  the  sphincter  above  and  on  either  side, 
and  below  by  depressing  the  uvula  and  the 
verumontanum.  This  stratum  of  muscular 
fibres  can  be  raised  with  a  little  careful  dissec- 
tion ;  a  few  fibres  must  be  divided,  which  now 
and  then  change  their  direction,  and  join  some 
of  the  deeper  orders  :  this  separation  is  difficult 
and  can  be  but  imperfectly  made  on  the  lateral 
regions,  but  on  the  anterior  and  posterior  it  can 
be  fully  accomplished.  The  second  order  of 
muscular  fibres  is  circular  or  transverse;  they 
are  paler,  weaker,  and  more  scattered  than  the 
former,  particularly  towards  the  superior  part 
of  the  bladder,  where  they  are  often  indistinct. 
As  they  descend  they  increase  in  thickness,  par- 
ticularly near  the  cervix,  where  they  are  so 
close  and  distinct  as  to  have  induced  many  to 
consider  them  as  a  sphincter  to  the  bladder, — a 
term,  however,  to  which  they  do  not  appear  to 
have  been  entitled,  for  there  is  no  distinction 
between  the  fibres  in  this  situation  and  those 
which  have  a  parallel  course  at  a  greater  dis- 
tance ;  and  inasmuch  as  the  latter  are  obviously 
designed  to  contract  the  organ  and  to  expel  its 
contents,  it  is  most  probable  that  the  former 
must  contribute  to  the  same  effect,  and  forcibly 
expel  the  last  drops  which  it  contains  :  indeed 
it  is  impossible  to  draw  such  a  line  of  distinc- 
tion in  this  lamina  as  could  denote  the  limit 
between  the  expelling  and  the  retaining  or 
sphincter  fibres.  In  addition  to  this  plane  of 
circular  fibres,  several  others  may  also  be  ob- 
served taking  a  parallel  direction  ;  thus  we  oc- 
casionally find  transverse  bands  superficial  to 
the  longitudinal  plane,  both  on  the  anterior  and 
posterior  regions  in  different  situations.  We  very 
generally  also  find  them  near  the  superior  fun- 
dus,  and  constantly  on  the  anterior  and  lateral 
parts  of  the  neck,  where  they  cover  the  decus- 
sation  of  the  longitudinal  fibres.  In  the  inter- 
val between  the  ureters,  these  transverse  fibres 
are  very  distinct,  particularly  above,  where  they 
usually  form  a  very  distinct  cord,  arched  a  little 
upwards :  this  semilunar  band  or  projection 
may  be  better  seen  when  the  bladder  is  opened ; 
it  corresponds  to  the  base  of  the  trigone,  ex- 
tends from  one  ureter  to  the  other,  and  is  im- 
mediately in  front  of  the  pouch  or  bas  fond  of 
the  bladder,  which  is  so  well  marked  in  the 
adult  and  old.  Throughout  the  rest  of  the 
trigone  the  circular  fibres  are  by  no  means  so 
distinct  or  strong  as  they  are  behind  it,  or  as 
they  are  towards  the  anterior  and  lateral  parts 


of  the  cervix.  This  circular  plane  of  fibres  may 
next  be  raised ;  it  is  almost  impossible  to  do 
this  completely,  because  many  of  them  deviate 
from  that  course,  and  join  into  the  next  or  third 
lamina,  taking  a  totally  different  course;  the 
separation,  however,  can  be  accomplished  suffi- 
ciently to  demonstrate  the  peculiar  arrange- 
ment of  the  third  plane  of  fibres,  not  all  over 
the  bladder,  but  only  in  particular  situations, 
namely,  in  the  greater  part  of  the  anterior 
and  posterior  regions,  but  only  very  imper- 
fectly on  the  superior  fundus,  and  on  the 
sides,  and  not  at  all  on  the  trigone.  Wherever 
this  third  layer  is  exposed,  the  fasciculi  appear 
very  large  and  thick,  and  present  a  very  remark- 
able appearance  and  course,  not  unlike  the 
inner  surface  of  the  cavities  of  the  heart.  Large 
fleshy  bundles,  bearing  some  resemblance  to 
the  carneae  columnse,  separate,  unite  again,  and 
again  subdivide,  the  fibres  taking  various  direc- 
tions, and  inclosing  interstices  of  the  mucous 
surface  of  various  size  and  form  :  several  of  the 
fibres  also  join  those  of  the  circular  plane.  It 
is  owing  to  this  reticularly  arranged  stratum  of 
muscular  fibres  that  the  bladder,  when  opened, 
presents  its  peculiar  irregular  surface,  which  in 
some  cases,  particularly  if  the  bladder  have 
been  hardened  in  alcohol,  resembles  a  honey- 
comb surface.  If  the  bladder  which  has  been 
opened  be  everted,  then  carefully  closed  and 
distended,  this  reticular  coat  will  become  very 
distinct  when  the  mucous  membrane  has  been 
removed.  Its  action  during  life  must  obviously 
be  to  contract  the  capacity  of  the  bladder  in 
every  direction.  When  the  internal  surface  of 
the  bladder,  even  in  the  healthy  state,  is  in- 
spected, the  different  orders  of  muscular  fibres 
become  very  apparent;  and  when  this  coat  has 
become  thickened  from  any  of  those  causes  which 
are  well  known  to  produce  thickening,  some 
of  the  fasciculi  often  project  into  the  bladder : 
such  a  condition  of  the  organ  is  named  a  co- 
lumnar state  of  the  bladder.  In  cases  of  irritable 
bladder,  when  calculous  symptoms  have  been 
present,  and  the  bladder  has  been  sounded  in 
consequence,  these  fleshy  projections  meeting 
the  extremity  of  the  sound,  have  in  some  in- 
stances deceived  the  surgeon  into  the  idea  of 
the  existence  of  a  calculus,  and  this  is  still  more 
likely  to  occur  should  there  be  any  gritty  mat- 
ter adhering  to  their  surface.  Some  of  those 
recorded  cases  of  the  operation  for  lithotomy, 
in  which  no  stone  could  be  detected,  although 
the  symptoms  of  the  disease  previously  existed, 
may  admit  of  explanation  by  a  knowledge  of 
this  fact.  In  the  bladder  of  some  persons  the 
muscular  fibres  do  not  perfectly  cover  the  mu- 
cous surface,  particularly  if  the  organ  be  very 
capacious.  In  such  cases  the  mucous  membrane 
may  be  pushed  through  some  of  the  cells  or 
meshes  of  the  muscular  fibres,  and  thus  a  hernia 
of  the  mucous  coat  be  produced ;  that  is,  a  small 
pouch  or  purse  of  this  membrane  will  protrude 
between  the  muscular  fasciculi,  and  will  be 
covered  only  by  peritoneum  or  by  cellular 
tissue.  This  pouch  may  continue  to  increase 
in  size,  because  it  possesses  no  power  of  empty- 
ing itself,  and  the  muscular  fibres  around  its 
orifice  can  only  contract  the  latter  without 


BLADDER,  NORMAL  ANATOMY. 


affecting  the  sac  itself;  hence  a  process  of  this 
sort  may  enlarge  indefinitely,  and  has  been 
known  in  some  cases  to  have  formed  a  part  of 
the  contents  of  an  inguinal  hernia.  Pouches  of 
this  nature,  for  there  may  be  several  in  the 
same  individual,  sometimes  contain  calculi,  the 
latter  having  probably  been  the  cause  of  the 
former,  inasmuch  as  the  muscular  coat  having 
been  excited  by  the  irritation  of  the  stone  to 
increased  action,  has  forcibly  pressed  the  latter 
into  one  of  the  cells  of  the  mucous  membrane, 
which  has  then  become  enlarged  and  protruded, 
so  as  to  contain  the  calculus  impacted  in  it. 
The  consequence  of  this  occurrence  to  the  indi- 
vidual, however,  is  often  a  fortunate  remission 
of  suffering,  because  the  stone  being  now  fixed 
in  a  cell,  ceases  to  excite  pain  or  irritation  :  it  is 
by  occurrences  of  this  nature  that  the  boasted 
and  sometimes  fortunate  efficacy  of  certain 
lithontriptic  medicines  as  cures  for  stone  is  to 
be  explained. 

The  exact  arrangement  of  the  muscular  fibres 
at  the  neck  of  the  bladder  has  not  been  very 
accurately  explained ;  some  describe  them  as 
arranged  circularly  so  as  to  constitute  a  true 
sphincter  :  this  opinion  is  maintained  by  John 
Bell,  System  of  Anatomy,  vol.  iv.  p.  159;  also 
by  Palfin,  Anat.  torn.  i.  p.  163;  by  Meckel, 
Anat.  vol.  iii.  p.  564 ;  by  Bayle  and  others. 
Sir  Charles  Bell  also  describes  a  sphincter 
vesicae  to  exist,  but  places  it  in  a  different  situa- 
tion from  that  usually  assigned.  His  description 
of  this  muscle  is  as  follows  : — "  to  exhibit  it,  cut 
off  all  the  appendages  to  the  bladder  except 
the  prostate  gland,  make  an  incision  into  the 
fundus  and  invert  it,  dissect  off  the  inner  mem- 
brane from  around  the  orifice  of  the  urethra ; 
a  set  of  fibres  will  be  discovered  on  the  lower 
half  of  the  orifice  running  in  a  semicircular 
form  round  the  urethra ;  these  make  a  band  of 
about  half  an  inch  in  breadth,  particularly 
strong  on  the  lower  part  of  the  opening,  and 
having  mounted  a  little  above  the  orifice  on 
each  side,  they  disperse  a  portion  of  their  fibres 
in  the  substance  of  the  bladder;  a  smaller  and 
weaker  set  will  be  seen  to  complete  their  course 
surrounding  the  orifice  on  the  upper  part,  to 
these  sphincter  fibres  a  bridle  is  joined  which 
comes  from  the  union  of  the  muscles  of  the 
ureters ;  this  is  the  most  posterior  part  of  all 
the  muscles  which  embrace  the  urethra,  it  re- 
sembles the  sphincters  of  the  other  hollow  vis- 
cera; forexample,thatof  thepylorieorificeof  the 
stomach."*  The  great  advantage  of  the  sphincter 
as  thus  described  must  be,  as  Sir  C.  Bell  says, 
to  prevent  the  fluids  from  the  seminal  vessels 
and  from  the  ducts  of  the  prostate  gland,  falling 
back  into  the  bladder,  as  also  to  protect  the  ori- 
fices of  these  ducts  from  exposure  to  the  urine 
when  the  bladder  is  closed,  and  that  without 
this  arrangement  it  would  be  inconceivable  how 
the  contents  of  the  vesiculae  seminales  could  be 
discharged  forwards,  or  how  the  urine  could  be 
retained  while  the  seminal  discharge  was  being 
made.  We  must  remark,  that  after  frequent 
examinations  of  this  region,  we  cannot  satisfy 
ourselves  of  the  existence  of  this  particular  ar- 

*  Treatise  on  Diseases  of  the  Urethra,  &e.  p.  14. 


383 

rangement,  although  we  are  convinced  that  the 
orifice  is  furnished  with  a  sphincter  such  as  we 
shall  presently  describe.  Moreover,  we  believe 
that  the  prostatic  secretion  is  more  or  less  ex- 
pressed at  each  evacuation  of  the  urine,  inas- 
much as  the  longitudinal,  the  principal  detrusor 
fibres  of  the  bladder,  are  fixed  into,  expand 
upon,  and  must  compress  this  gland,  especially 
at  the  commencement  of  the  process,  although 
they  obviously  can  have  no  effect  on  the  vesi- 
culae  seminales,  vasa  deferentia,  or  their  contents. 
The  existence  of  a  true  muscular  sphincter 
is  denied  by  Sabatier,  Anat.  torn.  ii.  p.  403; 
Marjolin,  torn.  ii.  p.  473 ;  also  by  Bichat, 
Anat.  desc.  torn.  v.  p.  147;  byBoyer,  Anat. 
torn.  iv.  p.  490  ;  by  Cloquet,  Anat.  torn.  ii.  p. 
1050;  by  Portal,  Anat.  torn.  v.  p.  401;  the 
latter,  however,  describes  the  urethral  orifice  as 
surrounded  by  oblique  muscular  fasciculi. 
VN  ins  low  also,  Anat.  torn.  ii.  p.  210,  denies  a 
true  sphincter,  but  ascribes  the  ofHce  of  such 
to  the  muscular  fasciculi  which  pass  from  the 
pubis  to  the  bladder.  Wilson  (Lectures  on  the 
Urinary  and  Genital  Organs,  p.  57,)  denies 
the  existence  of  any  regular  sphincter,  but 
thinks,  from  the  distribution  of  some  fibres 
at  the  beginning  of  the  urethra,  and  which  pass 
round  it  semicircularly  from  the  forepart  and 
meet  the  descending  fibres  behind,  that  the 
contraction  of  these,  assisted  by  those  of  the 
urethra  nearer  the  penis  (compressores  urethrae), 
may  be  considered  as  sufficient  to  prevent  the 
urine  passing  from  the  bladder  into  the  urethra. 
Several  of  the  foregoing  writers  who  deny  a 
muscular  sphincter  to  the  bladder,  consider, 
nevertheless,  that  its  orifice  is  closed  by  a  pe- 
culiar tissue  which  resists  the  ordinary  tendency 
of  the  muscular  coat  to  expel  its  contents,  but 
which  is  capable  of  yielding  to  the  increased 
force  which  is  exerted  in  the  ordinary  evacua- 
tion. Thus  Bichat  describes,  as  placed  between 
the  mucous  lining  and  the  external  cellular 
tissue,  a  dense  white  fibrous  substance,  con- 
tinuous with  the  muscular  fibres  which  are  in- 
serted into  it,  a  small  process  of  this  prolonged 
posteriorly  to  the  uvula,  and  another  anteriorly 
to  the  verumontanum.  This  substance  is 
not  muscular,  and  presents  a  passive  organic 
resistance.  Cloquet,  Boyer,  and  Marjolin  con- 
cur in  the  same  account ;  it  is  difficult,  how- 
ever, te  reconcile  with  such  a  condition  of  parts 
the  phenomena  which  not  un frequently  occur 
in  disease,  such  as  paralysis  and  incontinence 
of  urine  in  cases  of  injury  of  the  spine,  or  of  the 
nervous  system ;  or  again,  retention  of  urine 
from  irritation  in  this  situation  caused  either  by 
local  inflammation,  or  through  sympathy  with 
some  adjacent  diseased  organ,  or  by  some  pe- 
culiar acrimony  in  the  urine.  A  muscular  struc- 
ture is  more  reconcilable  with  these,  and  with 
many  other  pathological  facts,  than  an  elastic, 
or  fibrous,  or  resisting  tissue,  such  as  this  part  is 
stated  to  be  furnished  with.  The  result  of  our 
examination  convinces  us  that  the  organization 
of  this  part  is  very  peculiar,  and  that  the  neck 
of  the  bladder  is  closed  by  a  power  more  than 
that  of  a  mere  elastic  tissue.  Elasticity  no  doubt 
resides  in  this  structure,  and  we  admit  to  a  con- 
siderable extent,  as  it  docs  in  almost  every  ani- 


384 


BLADDER,  NORMAL  ANATOMY. 


mal  tissue,  except  perhaps  mucous  membranes: 
elasticity  exists  at  the  pylorus  and  at  the  anus, 
although  true  muscular  and  sphincter  fibres  are 
evident  at  both  these  outlets.  When  this  region 
is  carefully  examined  in  the  male  subject,  we 
shall  find  that  immediately  behind  the  pubis,  on 
the  anterior  and  lateral  reflections  of  the  pelvic 
fascia,  to  these  ligaments  numerous  muscular 
fibres  of  the  bladder  are  attached ;  these  are 
chiefly  longitudinal,  but  there  are  also  several 
transverse  arched  or  semilunar,  some  upon,  and 
others  underneath  the  longitudinal  fibres,  and 
with  which  many  of  them  are  continuous.  None 
of  these  arched  fibres  pass  around  or  behind  the 
prostate  so  as  to  encircle  this  region.  The  longi- 
tudinal, the  transverse  and  decussating  or  inter- 
lacing fibres  in  this  situation,  are  in  greater 
abundance,  and  may  be  raised  in  successive 
laminae.  Veins  and  nerves  are  very  manifest  in 
and  between  these;  several  of  the  longitudinal 
fibres  of  the  deeper  laminae  pass  in  so  deeply  as 
to  approach  the  mucous  surface.  When  the 
several  strata  of  longitudinal  fibres  have  been 
raised  from  the  front  and  lateral  parts  of  this 
region,  the  circular  fibres  of  the  bladder  become 
distinct,  but  do  not  appear  so  proportionably 
increased  as  were  the  longitudinal ;  but  on  de- 
taching more  completely  the  longitudinal  strata 
down  to  the  circumference  of  the  very  opening 
of  the  urethra,  a  distinctly  fibrous,  that  is,  mus- 
cular tissue,  is  evident,  bounding  this  opening 
laterally  and  superiorly,  but  not  below.  This 
muscular  fasciculus  is  not  intimately  connected 
to  the  general  circular  coat ;  it  appears  redder, 
and  of  a  closer  texture,  and  will  be  found  to  be 
attached  to  the  fibrous  or  tendinous  substance 
forming  the  anterior  part  of  the  trigone  on  each 
side  of  the  uvula,  behind  which  it  does  not 
pass.  The  longitudinal  fibres  are  inserted  partly 
into  this  semicircular  muscle,  much  in  the  same 
manner  as  the  levatores  ani  are  inserted  into  the 
circumference  of  the  anus.  This  structure  we 
consider  to  be  partly  elastic,  but  essentially 
muscular;  it  bounds  the  urethral  opening  late- 
rally and  above,  but  not  below;  the  slight  pro- 
jection of  the  uvula  in  the  latter  situation,  and 
the  elasticity  and  gentle  slate  of  contraction 
natural  to  all  the  sphincter  muscles,  will  pre- 
serve this  opening  in  a  constantly  closed  state 
during  the  quiescent  and  normal  condition  of 
the  parts.  This  arrangement  is  on  a  level  with 
the  uvula,  and,  of  course,  behind  the  orifices  of 
the  prostate  ducts,  although  the  base  of  that 
gland  extends  further  back  than  this  sphincter. 
We  have  repeatedly  examined  beneath  the 
uvula  for  muscular  fibres,  but  have  found  none 
in  a  transverse  direction  ;  there  is,  therefore,  no 
portion  of  a  sphincter  in  that  spot,  and  hence 
one  advantage  of  the  slight  elevation  caused  by 
the  uvula  and  by  that  portion  of  the  prostate 
gland  denominated  its  middle  lobe,  which  cor- 
responds to  it :  indeed  sphincter  fibres  in  this 
spot  would  be  not  only  useless,  but  injurious,  as 
they  could  scarcely  exist  without  interfering 
with  the  ejaculatory  ducts.  We  conceive,  then, 
that  the  urine  is  retained  in  the  bladder  partly 
by  the  relaxed  or  passive  state  in  which  its 
muscular  coats  usually  remain  until  they  are 
excited  by  the  sense  of  distension,  partly  also 


by  the  urine,  when  only  in  a  moderate  quantity, 
gravitating,  not  towards  the  neck,  but  distending 
the  inferior  fundus,  which  lies  on  a  level  lower 
than  that  of  the  former,  and  principally  by  the 
dense  muscular,  elastic,  vascular,  and  nervous 
tissue  which  surrounds  three-fourths  of  the 
orifice  of  the  bladder.  The  gentle  contraction  of 
the  latter  raises  the  uvula  into  the  calibre  of  the 
opening,  while  the  remaining  sides  are  pressed 
into  contact  with  it,  and  thus  the  bladder  is 
closed.  When  distension  excites  the  usual  feel- 
ing, the  muscular  coat  contracts,  the  sphincter 
relaxes,  phenomena  exactly  corresponding  to 
those  which  take  place  under  similar  circum- 
stances in  the  rectum  and  anus ;  and  as  the 
levatores  ani  expand  the  anal  opening  by  draw- 
ing the  sphincter  fibres  outwards  at  the  time 
the  expulsive  powers  of  the  rectum  are  dis- 
charging its  contents,  so  the  longitudinal  fibres 
of  the  bladder  draw  out  from  "the  axis  of  the 
urethral  opening  the  relaxed  sphincter  which 
encompasses  three-fourths  of  it,  while  the 
middle  band  of  the  posterior  longitudinal  will 
plainly  depress  the  uvula  and  expand  the  orifice 
in  that  aspect,  and  will  even  retract  and  depress 
the  verumontanum,  thereby  freeing  the  passage 
into  the  urethra,  and  retracting  that  sentient 
caruncle  from  the  irritating  influence  of  the 
urinary  stream. 

The  next  coat  of  the  bladder,  the  fourth  of 
some  anatomists,  or  the  second  common  of 
others,  is  the  deep  cellular,  or  more  properly 
the  submucous  cellular  coat,  by  some  also  de- 
nominated the  nervous  tunic.  This  coat  invests 
the  whole  organ  and  connects  the  muscular  and 
mucous  tissues  intimately  yet  loosely  ;  it  con- 
tains no  adipose  matter,  but  is  very  filamentous, 
extensible,  and  elastic:  in  it  are  found  those 
vessels  and  nerves  which  are  to  supply  the  in- 
ternal surface  of  the  bladder,  and  which,  except 
in  some  situations,  are  not  very  numerous  when 
compared  with  those  in  the  other  hollow  vis- 
cera. This  coat,  though  essentially  cellular,  pre- 
sents very  many  fibrous  threads  through  it,  on 
which  much  of  its  strength  appears  to  depend, 
particularly  in  those  places  where  the  muscular 
coat  is  deficient.  When  the  bladder  is  fully 
distended,  if  we  dissect  off  the  muscular  fibres 
carefully  without  injuring  this  tissue,  the  mu- 
cous membrane  still  remains  supported  ;  but 
as  soon  as  a  portion  of  this  coat  is  detached, 
the  mucous  membrane  projects  in  an  unsup- 
ported sacculated  manner.  This  coat  corre- 
sponds with  that  elastic  tissue  in  the  parietes 
of  the  small  intestines  in  some  animals,  out  of 
which  the  substance,  commonly  termed  catgut, 
is  formed. 

The  third  proper  coat  is  the  mucous  or  lining 
membrane,  to  expose  which  the  bladder  must 
be  opened  by  a  perpendicular  incision  along 
its  anterior  region.  This  tunic  is  but  a  portion 
of  the  genito-urinary  mucous  membrane,  and  is 
continuous  with  that  lining  the  ureters  above, 
and  the  urethra  below.  The  vesical  portion  of  this 
membrane  is  very  thin,  has  a  soft  and  smooth  feel 
caused  by  the  mucous  fluid  which  lubricates  it; 
its  colour  is  very  pale  in  the  natural  condition, 
although  in  catarrh  or  in  chronic  inflammation 
it  presents  a  general  vascular  appearance ;  but 


BLADDER,  NORMAL  ANATOMY. 


385 


in  health  the  mucous  surfaces  of  the  intestinal 
tube  anil  of  this  organ  form  a  strong  contrast, 
more  particularly  if  the  vessels  of  both  have 
been  injected  with  coloured  size;  the  former  will 
then  assume  the  colour  of  the  injection,  the  lat- 
ter will  continue  pale,  although  numerous  ves- 
sels become  apparent  in  the  submucous  tissue. 
The  mucous  lining  of  the  bladder  in  the  healthy 
state  does  not  present  any  distinct  follicles  or 
cryptae  except  near  the  cervix,  which  become 
very  distinct  in  chronic  disease.  A  cuticular  or 
eptdermoid  covering  cannot  be  detected  in 
health,  although  in  certain  states  of  disease  a 
substance  very  similar  to  cuticle  is  occasionally 
discharged  in  shreds  and  flakes.  When  the  blad- 
der is  empty  and  contracted,  the  mucous  mem- 
brane is  thrown  into  numerous  rugae,  existing 
chiefly  in  a  transverse  direction,  which  are  most 
distinct  if  a  very  recently  contracted  bladder  be 
examined.  When  the  organ  is  distended,  these 
ruga;  disappear,  so  that  their  existence  may  be 
considered  as  evincing  a  want  of  elasticity  in 
this  tissue.  This  membrane  presents  some  pecu- 
liarities throughout  the  extent  of  a  small  region 
named  the  *  trigone'  or  the  'velum'  of  the 
bladder :  this  term  is  applied  to  a  small  triangular 
space,  nearly  equilateral,  situated  about  the 
middle  of  the  inferior  region,  and  leading  to  the 
neck  of  the  bladder.  The  base  of  this  space  is  a 
lunated  line  leading  from  the  orifice  of  one 
ureter  to  the  other ;  the  sides  are  marked  by 
lines  which  converge  forwards  from  these  open- 
ings to  a  slight  projection  at  the  neck  of  the  blad- 
der named  the  <  uvula,'  which  is  immediately 
behind  or  rather  in  the  orifice  of  the  urethra. 
Throughout  the  area  of  this  space  the  mucous 
membrane  is  very  smooth  and  free  from  rugae 
or  folds,  as  it  adheres  closely  to  the  fibrous  or 
compact  cellular  substance  beneath  :  it  is  also 
more  vascular,  being  generally  of  a  delicate  rose 
colour,  or  variegated  with  fine  vessels,  and  when 
minutely  examined  with  a  magnifying  lens 
numerous  fine  villi  can  be  discerned.  On  the 
whole  this  surface  appears  to  be  delicately  and 
peculiarly  organized,  and  no  doubt  possesses 
higher  sensibility  than  the  remainder  of  the  in- 
ternal surface  of  the  organ.  The  posterior  part 
of  the  trigone  is  thinner  than  the  anterior  ;  the 
line  which  marks  its  base  is  a  thickened  band  of 
the  circular  or  transverse  muscular  fibres, behind 
which  the  inferior  fundus  of  the  bladder  is  fre- 
quently dilated  into  a  pouch  which  presses 
against  the  rectum,  and  where  a  calculus  some- 
times rests,  so  as  to  elude  the  search  of  the 
sound  unless  the  finger  be  introduced  into  the 
rectum  :  in  old  persons  this  pouch  sometimes 
remains  constantly  full  of  urine,  the  muscular 
coat  of  the  bladder  not  being  able  to  contract 
it.  The  lines  which  form  the  sides  of  the  tri- 
gone, and  which  extend  from  the  orifices  of 
each  ureter  to  the  uvula,  are  composed  of  a 
slight  projection  of  the  mucous  membrane,  be- 
neath which  is  some  cellular  tissue,  and  in 
some  cases  a  few  pale  muscular  fibres  are  dis- 
tinctly seen.  These  lateral  lines  are  not  in 
general  very  distinct,  at  least  in  the  healthy 
bladder;  their  distinctness  is  owing  to  little 
more  than  being  the  borders  of  this  space.  In 

VOL.  I. 


some  cases,  particularly  when  the  prostate  has 
been  enlarged  or  the  urethra  obstructed,  they 
are  found  very  distinct,  the  muscular  fibres 
they  contain  being  thickened  even  in  a  grcah-r 
degree  than  the  other  portions  of  the  muscular 
coat  of  the  bladder.  These  lateral  fasciculi 
appear  to  be  little  more  than  some  of  the  lon- 
gitudinal muscular  fibres  of  the  bladder  con- 
verging towards  its  cervix.  Sir  C.  Bell, 
however,  has  attached  a  particular  importance 
to  these  muscles,  which  he  denominates  the 
"  muscles  of  the  ureters :"  his  description  of 
their  attachments  and  use  is  as  follows,  in  his 
own  words  : — "  The  use  of  these  muscles  is  to 
assist  in  the  contraction  of  the  bladder,  and  at 
the  same  time  to  close  and  support  the  mouths 
of  the  ureters."  "  They  guard  the  orifices  of 
the  ureters  by  preserving  the  obliquity  of  the 
passage,  and  by  pulling  down  the  extremities  of 
the  ureters  according  to  the  degree  of  the  con- 
traction of  the  bladder  generally."* 

It  appears  very  questionable  how  far  this 
statement  as  to  the  structure  of  these  lines  is 
generally  correct,  and  it  is  still  farther  doubtful 
whether  the  use  assigned  is  correctly  ascribed 
or  not ;  for  it  may  be  remarked  that  these  lines 
are  often  very  faintly  traced,  that  the  muscular 
structure  within  them  is  sometimes  very  in- 
distinct, that  in  females  it  is  scarcely  observable, 
in  very  young  children  also  of  either  sex  it  is 
not  well  developed  ;  whereas  if  such  an  import- 
ant office  as  that  of  guarding  the  ureters  de- 
pended on  these  muscular  fibres,  it  is  most 
probable,  and  indeed  is  even  certain  that  their 
presence  would  be  constant  and  their  deve- 
lopment more  uniform.  Again,  the  fact  of  the 
dead  bladder  when  fully  distended  with  fluid,  or 
even  with  air  when  the  urethra  is  tied,  and  the 
contents  not  escaping  through  the  ureters,  is  a 
strong  proof  that  the  oblique  or  valvular  direc- 
tion of  the  latter  is  the  true  cause  of  the  non- 
regurgitation,  and  that  it  does  not  depend  on 
the  contraction  of  any  particular  muscular 
fibres.  Again  too,  in  animals  this  structure,  as 
described  by  Sir  C.  Bell,  is  not  at  all  obvious 
although  the  ureters  have  the  same  oblique 
course  as  in  man  ;  it  would  rather  appear  that 
these  muscular  bands,  which  are  occasionally 
very  distinct  along  the  sides  of  the  trigone,  are 
only  portions  of  the  longitudinal  fibres,  and 
that  their  action  will  be  to  shorten  the  trigone, 
to  draw  its  base  forward,  and  thus  to  assist  in 
empty  ing  the  bladder.  They  may  doubtless  assist 
in  fixing  the  orifice  of  the  ureters  and  moving 
these  in  proportion  as  the  surrounding  parts  are 
affected,  but  the  opinion  that  the  preservation 
of  the  valvular  or  oblique  course  is  depending 
upon  them  appears  to  be  invalidated  by  the  fore- 
going remarks,  as  well  as  bythe  following  expe- 
riment. The  healthy  bladder  of  an  adult  male, 
recently  dead,  was  opened  to  a  small  extent  on 
its  fore-part,  and  the  sides  of  the  trigone  were 
cut  by  a  sharp-pointed  bistoury  passed  beneath 
each  of  them  ;  the  urethra  was  then  tied,  and  the 
bladder  carefully  closed  :  its  cavity  was  next 
fully  distended  with  water,  and  the  fluid  was 

*  Medico-Chir.  Trans,  vol.  Hi.  p.  178. 
2  c 


386 


BLADDER,  NORMAL  ANATOMY. 


retained  for  u  considerable  time  although  it  was 
subjected  to  pressure,  and  was  afterwards  eva- 
cuated through  the  urethra  when  the  ligature  on 
the  latter  was  removed.  No  alteration  whatever 
from  the  ordinary  appearances  was  observed 
either  during  the  distension  or  the  subsequent 
emptying  of  its  cavity,  nor  did  any  regurgi- 
tation  take  place  into  the  ureters  in  either 
state.  The  same  experiment  with  air  instead 
of  water  was  repeated  and  with  the  same  effect. 
It  may  be  further  observed  that  the  ductus 
communis  choledochus  enters  the  duodenum  in 
a  similar  oblique  way,  that  no  regurgitation 
from  the  intestine  ever  occurs  into  it,  and  yet 
there  is  no  peculiar  muscular  fasciculus  attached 
to  its  orifice  which  could  execute  the  office 
ascribed  to  these  lateral  boundaries  of  the  tri- 
gone.  To  these  muscles  Sir  C.  Bell  also 
attributes  the  projection  into  the  bladder  of  the 
third  lobe  of  the  prostate  gland,  usually  called 
the  middle  or  Home's  lobe,  when  this  part  is  in 
a  state  of  enlargement.  There  are,  however,  such 
plain  and  simple  reasons  for  this  tumour  be- 
coming prominent  in  this  direction  rather  than 
in  any  other,  that  it  is  unnecessary  to  search  for 
an  explanation  in  the  action  of  these  muscles, 
the  undoubted  development  of  which  in  such 
cases  may  with  a  much  greater  degree  of  pro- 
bability be  considered  as  one  of  the  effects  and 
not  as  the  cause  of  this  projection. 

The  uvula  or  apex  of  the  trigone  varies  very 
much  in  its  appearance  in  different  persons. 
In  the  normal  state  it  is  very  small,  and  is 
most  distinctly  seen  by  making  only  a  small 
opening  in  the  upper  region  of  the  bladder 
when  in  situ,  and  looking  down  towards  the 
cervix ;  it  then  appears  as  a  small  projection 
in  the  middle  line  of  the  orifice  of  the  urethra, 
which  opening  it  thus  assists  to  close  or  to  fill. 
It  is  much  effaced  by  opening  the  bladder  from 
the  urethra  after  its  removal  from  the  subject, 
the  mucous  membrane  being  then  easily  ex- 
tended. This  projection  is  only  a  slight  full- 
ness or  prominence  of  the  mucous  membrane 
with  an  increase  in  the  submucous  tissue,  in 
which  small  follicles  or  cryptse  may  be  dis- 
cerned .  This  part  appears  rather  vascular,  and 
probably  possesses  some  peculiar  organization ; 
the  situation  also  which  it  holds,  as  well  as  its 
structure,  appear  to  indicate  it  to  be  the  seat  of 
a  proper  sensibility,  which,  when  affected,  ex- 
cites the  irritability  of  the  whole  organ.  Many 
facts  which  manifest  themselves  in  the  treat- 
ment of  urinary  diseases  seem  to  corroborate 
this  idea :  thus,  when  a  calculus  is  pressed 
against  this  part  of  the  mucous  membrane,  the 
pain  is  insupportable,  whereas  when  it  falls  or 
is  directed  into  the  inferior  fundus,  the  pain  is 
comparatively  trifling ;  also  when  a  bougie  or 
catheter  is  being  passed  into  the  bladder,  a 
peculiarly  acute  sensation  is  experienced  as  the 
instrument  comes  in  contact  with  this  par- 
ticular prominence.  The  uvula  in  the  child  is 
the  most  depending  part  of  the  bladder,  at 
least  in  the  erect  posture ;  ihis  is  not  the  case 
in  the  adult;  hence  probably  we  have  in  part 
the  reason  why  calculus  is  more  painful  in  the 
former  than  in  the  latter. 


The  trigone  in  the  female  bladder  comprises 
a  smaller  area,   but  is  broader  in  proportion 
than  in  the  male ;  it  is  not  so  distinct  or  firm 
in  the  former  as  in  the  latter,  where  it  is  sup- 
ported not  only  by  a  dense  substratum,  but 
also  by  the  vasa  deferentia,  vesiculae  seminales, 
and    prostate    gland.       This  portion  of   the 
bladder  is  so  firm  and  incompressible  that  it  is 
probable  the  cavity  corresponding  to   it  can 
never  be  wholly  obliterated,  so  that  in  the  most 
contracted  bladder  a  few  drops  of  fluid  arc 
still  retained.     The  uvula,  like  other  similar 
portions  of  the  mucous  membrane,  is  subject 
to  infiltration  and  increase  of  size  in  acute  in- 
flammatory affections,  as  also  to  chronic  and 
permanent  enlargement ;  and  as  it  lies  nearly 
over,  but  a  little  anterior  to  the  middle  lobe 
of  the  prostate  gland,  it  is  therefore  difficult, 
and   in  most  cases  impossible  to  distinguish 
affections  of  the  latter  from  those  of  the  former. 
The  uvula  is  smaller  in  the  female  than  in  the 
male ;  hence  the  opening  from  the  bladder  into 
the  urethra  is  larger  in  the  former  than  in  the  latter. 
Organization  of'  the  bladder. — a.  Arteries. — 
In  the  normal  state  the  bladder  is  not  very 
vascular ;  we  have  already  mentioned  that  its 
inner  surface  is  pale  and  free  from  any  red 
vessels.     The  arteries,  however,  of  the  bladder 
are  very  conspicuous  when  they  have  been  in- 
jected; they  are  long  and  tortuous,  and  are 
distributed    chiefly  along  the  sides,    inferior 
region,  and   cervix.     They   are  derived  from 
various   sources.     The  internal  iliac  or  hypo- 
gastric  on  each  side,  just  before  its  ligamen- 
tous  termination,  sends  off  one  or  two  vesical 
branches,  which  ramify  on   the  superior  and 
lateral  regions ;  the  middle  haemorrhoidal  and 
internal  pubic  also  very  generally  send  some 
considerable  branches  to  its  inferior  region  and 
cervix;    the  obturator  and   epigastric  vessels 
also  very  frequently  send  small  arteries  to  it 
anteriorly.     When  the  bladder  is  distended,  all 
these  vessels  are  seen  very  distinctly,  and  in 
the  muscular  coat  much  more  than  in  the  sub- 
mucous  tissue,  contrary  to  what  may  be  ob- 
served in  the  other  hollow  viscera ;  this,  how- 
ever, is  accounted  for  by  recollecting  that  the 
mucous  coat  of  the  bladder  does  not  in  its 
normal  and  healthy  condition  possess,  nor  does 
it  indeed  require  any  high  degree  of  organi- 
zation, as  it  is  simply  a  reservoir,  and  has  no 
important  function  to  execute  further  than  to 
secrete  a  fine  mucous  fluid  which  lubricates  its 
surface  and  defends  it  from  the  irritation  of  the 
urine.    This  secretion  mingles  with  the  urine, 
the  properties  of  which  it  alters  in  a  remark- 
able manner  whenever  it  is  increased  in  quan- 
tity, as  occasionally  occurs  in  chronic  disease 
of  this  organ.    The  muscular  coat  of  the  blad- 
der is  the  essential  agent  in  expelling  its  con- 
tents, and  is  therefore  more  fully  supplied  with 
vessels  than  any  other  of  its  tunics. 

b.  Veins. — The  veins  of  the  bladder  are 
large  and  numerous  inferiorly,  and  in  old  per- 
sons in  particular.  There  are  but  few  on  the 
superior  and  lateral  regions  except  towards  the 
inferior  part  of  the  latter.  In  the  child  the 
veins  are  very  inconsiderable:  this  difference 


BLADDER,  NORMAL  ANATOMY. 


387 


depends  on  this  circumstance,  that  the  veins 
which  are  seen  at  the  inferior  region  of  the 
bladder,  and  which  return  the  blood  from  its 
tunics,  do  not  belong  exclusively  to  this  organ, 
but  are  principally  derived  from  the  dorsal 
veins  of  the  penis;  they  also  receive  several 
branches  from  the  vesicula;  and  the  prostate, 
also  from  the  rectum  and  intervening  adipose 
substance.  In  the  adult  and  old  these  latter 
veins  are  very  numerous,  indeed  they  may  be 
said  to  form  a  perfect '  venous  plexus'  on  each 
side,  extending  from  the  termination  of  the 
ureter  to  the  prostate  gland.  All  these  veins 
are  considerably  less  developed  in  children, 
inasmuch  as  the  organs,  at  least  those  of  gene- 
ration, from  which  they  are  principally  de- 
rived, are  comparatively  small.  The  vesical 
veins  ultimately  discharge  their  blood  into  the 
internal  iliac  or  hypogastric  veins. 

c.  Lymphatics. — The  lymphatic  vessels  are 
tolerably  distinct,  more  particularly  inferiorly 
and  about  the  cervix.    They  intermingle  with 
the  lymphatics  of  the  rectum  and  of  the  neigh- 
bouring organs,  and    ultimately   lead  to  the 
internal  iliac  or  hypogastric  glands.   Indepen- 
dent of  dissection,  the  existence  of  absorbents 
in  the  bladder  is  proved  by  its  functions,  or 
by  the  changes  which  the    urine   undergoes 
when  long  retained  in  this  cavity, — a  portion 
of  its  water  is  absorbed,  and  the  residue  be- 
comes pungent,  high-coloured,  and  acrid. 

d.  Nerves. — The  nerves  of  the  bladder  are 
derived  from  the  hypogastric  plexus,  which  is 
constituted  of  two  orders  of  nerves,  viz.  some 
from  the  sacral  plexus  of  the  spinal  system, 
and  others  from  the  sympathetic  or  ganglionic 
system.   This  two- fold  supply  of  nerves  accords 
with  the  functions  of  this  organ,  and  entitles  it 
to  be  placed,  as  far  as  relates  to  the  properties 
of  its  muscular  coat,  among  the  mixed  muscles, 
being  in  part  voluntary  and  in  part  involuntary  : 
the  former  endowment  will,  of  course,  depend 
on  its  share  of  spinal  nerves,  the  latter  on  the 
sympathetic.   It  may  also  be  observed  that  the 
branches  of  the  latter  are  principally  distri- 
buted  about  the  cervix  and   inferior  region, 
while  those  of  the  former  are  seen  distinctly 
on  the  sides  and  superior  regions ;  but  in  all 
these  situations  these  nerves  are  more  or  less 
intermingled. 

The  cervix  of  the  bladder  is  of  a  com- 
pressed conical  form,  longer  below  and  on  the 
sides  than  above.  It  is  surrounded  in  the  male 
by  the  prostate  gland  ;  only  a  small  portion  of 
this  is  upon  its  upper  surface  :  in  the  adult  the 
neck  is  placed  nearly  horizontally  below  the 

fubis  and  behind  the  triangular  ligament, 
n  the  female  the  cervix  vesicce  is  closely  sur- 
rounded by  a  whitish  compact  follicular  tex- 
ture, not  possessing  any  perfect  capsule,  and 
therefore  without  the  accurate  form  of  or  any 
resemblance  to  the  prostate  gland  in  the  male. 
The  cervix  in  the  child  is  more  distinctly 
conical,  and  is  placed  in  a  more  oblique  or 
vertical  direction  than  in  the  adult.  The  term 
cervix  is  not  very  definitive,  as  there  is  no 
exact  limit,  at  least  in  the  human  subject,  to 
mark  this  region  as  in  quadrupeds ;  according 


to  most  writers  on  human  anatomy,  it  is  syno- 
nymous with  the  prostatic  portion  of  the 
urethra,  and  the  full  description  of  it  is  given 
by  such  in  connexion  with  the  anatomy  of  the 
urethra.  We  consider  the  neck  of  the  bladder 
to  be  that  contracted  portion  of  the  viscus 
which  is  embraced  by  the  base  only  of  the 
prostate  gland,  and  which  contains  internally 
and  below  the  slight  elevation  named  the 
uvula  of  the  bladder,  and  laterally  and  above 
the  peculiar  structure  which  fulfils  the  office 
of  a  sphincter. 

Having  particularly  noticed  the  situation  of 
the  bladder,  and  the  slight  change  of  position 
it  admits  of  in  consequence  of  its  change  in 
form,  we  shall  next  consider  its  attachments, 
or  the  media  by  which  it  is  retained  in  its  posi- 
tion, for  it  may  be  considered  as  nearly  a  fixed 
viscus.  The  bladder  is  held  in  its  position 
principally  by  three  connexions ;  first,  by  the 
peritoneum ;  secondly,  by  the  reflections  of  the 
pelvic  fascia;  and,  thirdly,  by  the  continuity 
of  its  cervix  with  the  urethra,  the  commence- 
ment of  the  latter  being  fixed  by  ligamentous 
connexions  to  the  arch  and  rami  of  the  pubes. 
First,  the  bladder  is  connected  by  certain  folds 
of  the  peritoneum  to  the  parietes  of  the  pelvis 
and  abdomen;  these  folds  are  named  the 
"  false  ligaments"  of  the  bladder,  and  are  five 
in  number,  two  lateral,  two  posterior,  and  one 
superior.  Each  of  the  lateral  ligaments  or 
folds  extends  from  the  lateral  region  of  the 
bladder  to  the  iliac  fossa,  and  contains  in  its 
duplicature  thevasa  deferentiain  the  male,  and 
the  round  ligament  of  the  uterus  in  the  female. 

The  posterior  folds  or  ligaments  are  also  two 
in  number;  they  lead  from  the  fore-part  of 
the  rectum  to  the  back  part  of  the  bladder. 
Each  of  these  folds  is  of  a  semilunar  form, 
(the  concavity  looking  forwards  and  upwards,) 
and  contains  the  ureter  posteriorly,  and  the 
obliterated  hypogastric  artery  anteriorly.  When 
the  bladder  is  distended,  these  posterior  folds 
are  very  short ;  but  when  it  is  contracted,  they 
are  distinct  and  long.  Between  them  the  pelvic 
cul-de-sac  of  the  peritoneum  descends,  which 
in  the  empty  state  of  the  bladder  and  rectum 
appears  deep,  narrow,  and  distinct,  but  in  the 
distended  condition  of  these  organs,  particu- 
larly of  the  former,  it  is  of  much  less  extent 
and  depth,  as  the  bladder  in  becoming  dis- 
tended rises  upwards  and  draws  with  it  the 
cul-de-sac  of  the  peritoneum :  hence  in  the 
distended  state  of  this  organ  the  triangular 
portion  of  its  inferior  region  which  is  uncovered 
by  peritoneum  is  increased  in  extent,  and  is 
larger  than  when  the  organ  is  contracted. 
Between  the  two  posterior  ligaments  one  or 
two  semilunar  folds  of  the  peritoneum  may 
be  generally  observed  on  the  posterior  surface 
of  the  bladder,  provided  the  latter  be  in  a  con- 
tracted state ;  these  folds  are  expanded  as  the 
bladder  enlarges,  and  thus  they  serve  to  ac- 
commodate the  serous  membrane  to  the  varying 
conditions  of  the  bladder  without  stretching  or 
extending  the  former — a  purpose  which  perito- 
neal folds  or  ligaments  in  general  are  intended 
to  answer. 

2  c  2 


388 

The  superior  fold  or  ligament  extends  from 
the  summit  of  the  bladder  to  the  posterior 
surface  of  the  recti  muscles,  and  is  partially 
reflected  over  the  remains  of  the  urachus  and 
hypogastric  arteries.  This  fold  rather  consists 
or  three  folds  wh'ich  diverge  below  and  con- 
verge towards  the  umbilicus;  they  present  a 
falciform  appearance  towards  the  abdomen, 
particularly  when  the  bladder  is  contracted. 
Jn  the  foetus  these  superior  folds,  particularly 
the  lateral,  are  very  distinct,  as  they  each  con- 
tain the  umbilical  artery.  The  urachus,  which 
is  in  the  centre,  is  also  at  that  age  very  distinct 
though  shorter;  its  vesical  end  is  often  pervious 
for  about  an  inch  :  it  is  always  closed  before  it 
arrives  at  the  umbilicus,  it  then  becomes  fila- 
mentous, and  is  soon  lost  on  the  umbilical 
arteries. 

The  second  medium  of  connexion  between 
the  bladder  and  the  parietes  of  the  pelvis  is 
the  vesical  fascia,  the  reflections  of  which  con- 
stitute the  true  ligaments  of  the  bladder.  The 
vesical  is  the  internal  lamina  of  the  pelvic 
fascia  reflected  from  the  latter  at  the  upper 
border  of  the  levatores  ani  muscles  :  it  covers 
the  internal  surface  of  this  muscle  on  each  side, 
and  descends  as  low  as  a  line  drawn  from  the 
inferior  border  of  the  symphysis  pubis  to  the 
spinous  processes  of  the  ischia.  On  this  level 
it  is  reflected  on  the  prostate  gland  and  on 
the  sides  of  the  bladder,  and  posterior  to  this 
organ  on  the  rectum  and  on  several  of  the 
pelvic  vessels  and  nerves.  The  anterior  or 
vesical  portion  of  this  fascia  is  distinct  and 
strong,  and  forms  a  pouch  on  each  side  of  the 
bladder  which  assists  in  closing  the  pelvis ; 
posteriorly  this  fascia  is  thin  and  cellular,  being 
perforated  by  several  vessels.  Its  anterior 
reflections  constitute  the  true  anterior  liga- 
ments of  the  bladder,  which  are  described  as 
arising  from  the  lower  margin  of  the  pubis  on 
either  side  of  the  symphysis,  then  passing  back- 
wards and  upwards  on  the  upper  surface  of 
the  prostate  gland,  and  expanding  on  the  an- 
terior region  of  the  bladder;  many  of  their 
fibres  become  continuous  with  the  muscular 
fibres  of  the  bladder.  A  depression  exists 
between  these  two  ligaments,  along  which  the 
dorsal  veins  of  the  penis  run  from  beneath  the 
arch  of  the  pubis  to  the  side  of  the  bladder 
in  their  course  to  the  internal  iliac  veins,  in 
which  they  terminate.  The  fascia,  however, 
is  not  deficient  in  this  depression  between  these 
ligaments,  but  is  continued  from  one  to  the 
other  so  as  to  line  this  hollow  and  to  cover  the 
upper  surface  of  these  veins.  The  anterior 
ligaments  present  a  smooth  concavity  towards 
the  abdomen  or  pelvis ;  their  perineal  or  infe- 
rior aspect  is  convex,  and  has  inserted  into  it 
the  posterior  lamina  of  the  inter-osseous  or 
triangular  ligament  of  the  urethra. 

The  true  lateral  ligaments  of  the  bladder  are 
also  two  in  number,  one  on  each  side ;  each  is 
continuous  with  the  anterior,  and  is  formed  by 
the  reflection  of  the  vesical  fascia  from  the 
internal  surface  of  the  levator  ani  muscle  to 
the  side  of  the  prostate  gland,  and  of  the 
bladder  immediately  above  and  outside  the 


BLADDER,  NORMAL  ANATOMY. 


vesiculse  seminales.  The  pelvic  and  vesical 
fasciae  will  be  more  particularly  noticed  in  the 
article  PELVIS. 

Lastly,  the  bladder  is  retained  in  situ  by 
the  attachments  of  the  cervix;  these  take  place 
not  only  directly  by  the  ligaments  which  have 
been  just  described,  but  also  indirectly  through 
its  connexion  to  the  urethra  and  of  the  latter 
to  the  pubes  through  the  medium  of  the  trian- 
gular ligament  of  the  urethra.  This  ligament, 
for  a  fuller  description  of  which  we  refer  to 
the  article  PERINEUM,  is  a  strong  aponeurosis 
intimately  connected  to  the  rami  of  the  pubes 
and  ischia,  and  there  continuous  with  the  obtu- 
rator fascia  of  each  side.  It  is  strong,  tense, 
and  unyielding,  and  closes  all  the  anterior 
portion  of  the  inferior  orifice  of  the  pelvis;  it 
is  perforated  by  a  small  opening,  through  which 
the  urethra  passes  about  an  inch  inferior  to  the 
bony  edge  of  the  pubes;  the  edges  of  this 
opening  are  continued  on  the  urethra  both  to- 
wards the  perineum  and  towards  the  pelvis. 
The  process  which  extends  in  the  former  or 
inferior  direction  is  lost  on  the  bulb  of  the 
urethra,  while  that  which  extends  in  the  pos- 
terior or  superior  direction,  and  which  is  more 
distinct  and  strong,  encompasses  the  mem- 
branous part  of  the  urethra,  (which,  while  in 
situ,  is  very  short,)  and  is  then  inserted  or 
becomes  continued  into  that  reflected  portion 
of  the  vesical  fascia  which  forms  the  true 
anterior  and  lateral  ligaments  of  the  bladder ; 
thus  the  commencement  of  the  urethra,  the 
prostate  gland,  and  the  neck  of  the  bladder, 
which  must  be  nearly  synonymous  with  the 
prostatic  portion  of  the  urethra,  are  all  retained 
in  a  nearly  fixed  position,  and  the  continuity 
of  the  different  aponoreuses  in  this  region 
serves  to  afford  mutual  strength  and  general 
security. 

The  bladder,  notwithstanding  the  foregoing 
connexions,  is  subject  to  displacement.  In  the 
male  this  occurrence  seldom  happens,  although 
in  some  cases  of  very  large  inguinal  or  scrotal 
herniae  this  viscus  has  been  gradually  drawn 
into  the  sac,  in  consequence,  most  probably, 
of  adhesion  between  it  and  the  omentum  or 
some  other  of  the  protruded  parts.  We  have 
already  mentioned  how  a  portion  of  the  lining 
membrane  may  become  protruded  between  the 
muscular  fasciculi  and  form  a  sac  which  may 
increase  to  a  considerable  size,  and  extend  into 
some  new  and  even  remote  situation.  In  the 
female  the  bladder  is  very  liable  to  partial 
pressure  as  well  as  to  displacement,  owing  to 
different  conditions  of  the  uterus,  such  as 
retroversion,  inversion,  and  prolapsus. 

BIBLIOGRAPHY.  —  Mangetus,  Uretemm  et  ve- 
sicae  urinariae  hist,  ex  variis  in  Bib.  Anat.  v.  i. 
Vogelmann  resp.  Janson,  Diss.  sist.  fab.  &c.  renum 
ct  vesicae  urinariae,  4to.  Mogunt.  1732.  Parsons, 
Description  of  the  human  urinary  bladder,  &c.  8vo. 
Lond.1742.  Beudt,  De  fabrica  et  usu  viscertim  uropo- 
eticorum,  4to.  Lugd.  Bat.  1744  (Rec.  in  Halleri 
Disp.  Anat.  vol.  iii.).  Walther,  De  collo  virilis 
vesicae,  4to.  Lips.  1745  (Rec.  in  Haller,  Coll.  diss. 
Anat.  vol.  v.).  Lieutaud,  Obs.  anat.  stir  la  structure 
de  la  vessie,  Mem.  de  1'Acad.  de  Paris,  1753. 
Weitbrecht,  De  figura  et  situ  vesicae  urinariae,  Com. 


Pctrop.  vol.  v.  Noot,  De  struct ura  ct  nsu  vcsicae 
urinariau  atquc  uretcrum,  4to.  Lugd.  Hat.  1767. 
Roeckhoven  de  Wind,  DC  uretcribus  ct  vcs.  urin. 
4lo.  Lugd.  Hat.  1784.  Richcrand,  Mem.  sur  1'ap- 
paroil  urinaire,  in  Mem.  de  la  Soc.  Mod.  d'Kmulat. 
An  viii.  Bell  on  the  muscles  of  the  ureters,  Mcd. 
Chir.  Trans,  v.  iii.  Wilson,  Lectures  on  the  struc- 


BLADDER,  ABNORMAL  ANATOMY 
OF  THE  URINARY.— Under  this  deno- 
mination it  is  proposed  to  include  all  variations 
from  the  natural  condition  of  the  organ,  whe- 
ther the  particular  variety  be  a  congenital  vice 
of  conformation  or  a  consequence  of  extra- 
uterine  disease. 


BLADDER,  ABNORMAL  ANATOMY.  389 

turc  and  physiology  of  the  male  urinary  organs,  &c. 
8vo.  Lond.  1821.  Sec  also  the  different  systems 
of  anatomy,  the  Tabulae  Scpti-ndrriin  of  Ntnihvini 
and  his  Observationes  anatomica;,  and  the  recent 
Memoir  of  Mr.  Guthrie  on  the  anatomy  and  diseases 
of  the  neck  of  the  bladder,  &c.  8v<*.  1834. 

(  R.  Harrison.) 

In  the  following  synopsis  may  be  seen  the 
several  affections  included,  as  well  as  the  order 
in  which  they  will  be  described  in  the  present 
article. 


Changes 


Congenital 


Acquired 


Of  conformation 


"Of  conformation 


Of  position 


Of  structure 


i  Septa. 

•?  Extrophy  or  extroversion. 

C  Persistance  of  the  urachus. 

s  Sacculi  or  cysts. 

)  Capacity,  increase  of. 

\  decrease  of. 

(..Introversion. 

^  Herniae,  inguinal. 

\  femoral. 

J  perineal. 

\,  vaginal. 

rlnflammation  with  its  consequences. 

{  Idiopathic  softening. 

Rupture. 
j  Fistulae. 
*  Haemorrhage. 

Fungoid  tumours. 

Varices. 

Scirrhus. 


Of  function 


t  Paralysis. 
'   $  Spasm. 

To  some  persons,  the  introduction  of  two  mented,  terminated 
functional  diseases,  paralysis  and  spasm,  in 
an  article  on  pathological  anatomy,  may  appear 
objectionable;  but  as  they  are  sometimes  con- 
sequences of  structural  change,  we  hold  that 
we  have  a  perfect  justification  for  their  ap- 
pearance. 

CONGENITAL    CONDITIONS. 

Numerical  changes. — Absence. — Among  the 
single  organs  of  the  body,  one  degree  of  nu- 
merical diminution  only  is  possible,  namely, 
their  absence.  Such  an  anomaly,  if  we  except 
true  cases  of  monstrosity,  should  be  extremely 
rare,  and  indeed  it  is  so;  for  as  all  unique 
portions  of  the  organization  are  called  upon 
to  perform  functions,  to  which  they  are  more  or 
less  exclusively  devoted,  it  is  rarely  that  any 
other  can  supply  their  place,  and  in  conse- 
quence, when  the  organ  is  wanting,  the  func- 
tion is  also  wanting. 

There  are  upon  record  a  certain  number  of 
instances  of  absence  of  the  urinary  bladder ; 
in  some  of  these  cases  the  ureters  have  been 
found  to  terminate  directly  in  the  urethra,  in 
others  they  have  been  inserted  into  the  rectum, 
in  others  they  have  communicated  with  the 
vagina.  Of  the  first  species  we  have  the  fol- 
lowing examples :  Lieutaud  *  mentions  the 
case  of  a  man,  aged  thirty-five,  in  whom  the 
ureters,  the  capacity  of  which  was  much  aug- 


immediately   below   the 

pubis  near  the  orifice  of  the  urethra.  Binnin" 
ger*  describes  the  case  of  Abraham  Clef,  in 
whom  there  was  no  urinary  bladder,  and  the 
ureters  opened  upon  the  urethra.  A  stylet, 
introduced  into  the  urethra,  passed  alternately 
into  the  one  and  the  other  ureter ;  the  ureters 
were  afterwards  separated  from  the  kidneys, 
and  the  stylet,  introduced  in  the  opposite  di- 
rection, met  with  no  obstacle  to  its  passage  into 
the  urethra. 

Of  the  second  species  we  have,  in  the  se- 
venth volume  of  the  Philosophical  Trans- 
actions, the  history,  given  by  Richardson,  of  a 
lad  residing  in  Yorkshire,  who  lived  to  the  age 
of  seventeen,  without  ever  having  passed  urine 
through  the  urethra,  and  who  had  still  enjoyed 
good  health.  The  only  inconvenience  he  suf- 
fered was  a  consequence  of  the  passage  of  the 
urine  into  the  rectum,  by  which  a  troublesome 
diarrhoea  was  kept  up.  Camperf  speaks  of 
five  similar  cases,  one  of  which  was  that  of 
a  female.  Klein  J  also  speaks  of  a  case.  In 
the  Nov.  Acta  Acad.  Nat.  cur.  ann.  i.  obs.  38, 
there  is  another  in  which  "  ureter  in  rectum 
intestinum  insertus  fuit."  And  in  the  Hist, 
de  1'Acad.  ann.  1752,  n.  4,  there  is  one  de- 


Hist.  Anat.  Mcd.  Liber  primus.  Obs.  1361. 


*  Obs.  Mod.  24,  cent.  2. 

t  In  Mem.  pour  le  Prix,  &c.  8vo.  edit,  tome  v. 
P.  9. 

\  llachit.  congenit.  Nov.  Eph.  Ac.  Nat.  Cur> 
vol.  i,  obs.  38. 


BLADDER,  ABNORMAL  ANATOMY. 


390 

scribed  under  the  head  :  "  Uretra  in  intestinum 
patens." 

Of  the  third  species,  cases  are  cited  by 
Haller*  and  by  Schrader.f  In  these  cases  there 
was  no  other  malformation.  In  the  foregoing 
enumeration  we  have  purposely  avoided  the 
introduction  of  cases  of  general  monstrosity  in 
which  the  urinary  bladder  was  absent. 

Plurality. — There  are  upon  record  a  certain 
number  of  cases  in  which  two  or  more  urinary 
bladders  are  said  to  have  existed.  Of  these 
some  appear  to  me  to  have  been  cases  in  which 
the  plurality  was  maintained  merely  because 
the  organ  was  divided  into  compartments, 
either  as  a  consequence  of  arrested  develop- 
ment or  of  the  formation  of  pouches,  by  the 
protrusion,  or  hernia  of  the  mucous  membrane 
of  the  organ.  The  following  case  related  by 
Blasius  belongs,  I  apprehend,  to  the  former 
species.  A  person  died  phthisical,  having  a 
"  double  bladder."  When  the  external  sur- 
face was  examined,  it  appeared  to  be  an  unique 
organ,  but  upon  being  opened  a  membranous 
septum  was  discovered,  by  which  the  organ 
was  divided  into  two  distinct  cavities.  The 
narrator  adds,  that  by  dissection  he  separated 
the  one  from  the  other,  so  that  the  longitudinal 
septum  was  formed  by  the  parietes  of  the  two 
bladders,  which  were  in  contact,  and  had 
become  united  the  one  to  the  other.  There  is 
a  case  of  a  similar  nature  described  by  Brom- 
field;  and  many  more  are  recorded  by  Mor- 
gagni  and  others. 

We  know  of  no  instance  in  the  human  sub- 
ject, with  the  exception  of  that  related  by 
Molinetti,J  in  which  a  plurality  of  urinary  blad- 
ders distinct  from  each  other  existed.  In  this 
case  there  does  not  appear  to  have  been  any 
thing  abnormal  in  the  organisation  except  in 
so  far  as  concerned  the  urinary  organs.  "  A 
woman  had  five  urinary  bladders,  as  many 
kidneys,  and  six  ureters,  two  of  which  were 
inserted  into  a  bladder  which  was  much 
larger  than  the  others ! !  the  remaining  four 
ureters  terminated  in  as  many  small  bladders, 
which  poured  their  urine  by  particular  canals 
into  the  larger  bladder."  Another  but  less 
carefully  described  case  of  the  same  kind  is 
mentioned  by  Fantoni,  in  his  Anat.  Corp.  Hum. 
diss.  7;  and  in  the  Acta  Physico-Medica 
Academiae  Csesareae  Nat.  Curios,  vol.  i.  obs. 


*  Element.  Physiologies,  vol.  vii.  p.  297. 

t  Nov.  Ephem.  Acad.  cur.  Nat.  vol.  i.  obs.  38, 
et  die  42,  obs.  68.  [The  Editor  has  in  his  posses- 
sion  the  preparation  of  a  female  foetus  which  lived 
some  days,  where  the  ureters  opened  through  the 
abdominal  parietes  on  each  side  of  the  pubic  region 
in  the  form  of  little  pouches  or  sacs,  in  which  was 
a  continuation  of  their  lining  membrane.  The 
urine,  as  it  distilled  from  the  kidney,  accumulated 
in  each  of  these  sacs  (in  very  small  quantity,  as 
they  were  incapable  of  containing  more  than  a 
drop  or  two,)  prior  to  its  oozing  out  upon  the  raw 
cutaneous  surface.  This  latter  was  deficient  of 
cuticle  for  a  surface  about  an  inch  and  a  half  in 
diameter ;  the  pubic  bones  and  the  inferior  fourth 
of  the  recti  and  tendinous  expansions  of  the  obliqui 
were  absent.  There  was  also  only  about  an  inch 
of  large  intestine  (coecum).— ED.] 

Dissert.  Anat.   Pathol,  lib.  vi.  cap.  7. 


83,  may  be  found  a  well-marked  case  oi 
duplicity  of  the  urinary  bladder  described  by 
Zuinger,  whose  account  is  accompanied  by  a 
plate,  which  perfectly  confirms  the  description ; 
but  this  case  occurred  in  an  ox. 

Septa. — Occasionally,  within  the  cavity  of 
the  bladder,  more  or  less  perfect  septa  are 
found,  by  which  that  organ  is  divided  into  two 
or  more  compartments.  This  condition  is  met 
with  or  occurs  under  two  very  different  circum- 
stances: in  one  it  is  a  congenital  affection, 
and  this  it  is  our  business  to  consider  in  this 
section ;  in  the  other  it  is  produced  by  and  is 
not  an  uncommon  consequence  of  retention  of 
urine  during  extra-uterine  life.  In  the  de- 
scription of  these  two  very  dissimilar  affections 
much  confusion  has  occurred,  in  consequence 
of  an  almost  universal  impression  that  they 
were  similar  the  one  to  the  other.  If  the 
theory  of  the  eccentric  development  of  organs, 
proposed  by  Geoffroy  St.  IJilaire,  and  extended 
by  M.  Serres,  be  admitted,  all  difficulty  in 
explaining  this  seemingly  singular  congenital 
phenomenon  vanishes.  M.  Serres  conceives 
that  he  has  triumphantly  established  the  fact, 
that  the  hollow  organs,  which  are  single  and 
placed  on  the  median  line,  are  composed  of 
two  moieties,  primitively  distinct  and  sepa- 
rate; so  that  according  to  him,  at  a  certain 
period  of  uterine  life,  there  exist  two  aortas, 
two  basilar  arteries,  two  superior  cavae,  and 
so  on.  Now  if  there  exist  two  vaginae,  two 
bladders,  <wo  uteri,  at  a  certain  epoch  of 
embryotic  life,  the  evolution  of  these  organs 
should  necessarily  present  three  successive 
periods:  a  first,  characterised  by  their  du- 
plicity and  their  complete  isolation ;  a  second, 
by  their  mutual  approach  and  union  upon  the 
median  line ;  a  third,  by  their  complete  fusion, 
which  constitutes  their  permanent  condition 
in  man  and  the  mammalia.  We  can  therefore 
conceive  that  at  the  moment  of  the  second 
period,  when  the  two  primitive  organs  are 
united,  the  parietes  of  both  being  entire  and 
in  contact  on  the  median  line,  there  will  be 
a  perfect  septum  separating  the  one  organ 
from  the  other.  At  the  commencement  of 
the  third  period  in  the  process  of  develop- 
ment, the  septum  is  destined  to  disappear, 
the  two  cavities  merge  into  one,  and  the 
work  of  development  in  the  organ  is  com- 
plete. Now,  in  the  evolution  of  all  the  organs, 
development  may  be  arrested  at  any  period  of 
its  progress:  it  may  be  arrested  before  the 
organs  come  into  contact,  in  which  case  there 
would  be  two  bladders ;  it  may  be  arrested 
after  they  have  formed  a  junction,  in  which 
case  a  complete  septum  would  exist,  as  in  the 
case  described  by  Blasius  ;  or  the  check  may 
not  occur  until  a  greater  or  less  portion  of  the 
septum  shall  have  disappeared. 

To  distinguish  the  congenital  affection  which 
is  a  consequence  of  arrested  development, 
from  the  acquired  affection  which  is  an  extra- 
uterine  disease,  and  is  commonly  an  effect  of 
retention  of  urine,  is  not  difficult.  In  the 
former  we  shall  always  find  that  the  entire 
of  each  pouch  is  invested  by  a  layer  of  mus- 
cular fibres  ;  in  the  latter,  it  will  be  found  that 


DJLADDEK,  ABNORMAL  ANATOMY. 


391 


in  one  of  the  two  compartments  no  such  mus- 
cular investment  is  present. 

Exlrophy  or  extroversion. — Extrophy  of  tho 
bladder  vvus,  up  to  a  comparatively  late  period, 
almost  universally  regarded  as  a  hernia  of 
that  organ;  and  it  was  not  until  about  the 
middle  of  the  last  century,  and  after  Tenon 
had  dissected  two  such  cases,  that  this  opinion 
was  shown  to  be  erroneous.*  Tenon  dis- 
covered that  there  was  a  complete  "  absence'7 
or  destruction  of  the  whole  of  the  anterior 
parietes  of  the  bladder;  and  that  the  tumour 
which  is  found  at  the  hypogastrium  is  only 
the  posterior  parietes  of  this  sac,  with  the 
"  trig-one"  pushed  forward  by  the  abdominal 
viscera,  as  if  for  the  purpose  of  blocking  up 
the  opening  caused  by  the  deficiency  of  sub- 
stance below  the  umbilicus.  On  the  surface 
of  the  tumour  which  is  there  presented,  and  at 
its  inferior  part,  we  see  the  urine  almost  con- 
tinually exuding  through  two  holes,  pierced  in 
the  centre  of  two  small  nipple-like  eminences, 
which  are  the  orifices  of  the  ureters.'  The 
insertion  of  these  conduits  of  the  urine  at  the 
inferior  part  of  the  tumour  indicates  that  the 
portion  of  the  bladder,  which  appears  upon 
the  exterior,  is  precisely  that  which,  in  the 
natural  state,  is  found  most  deeply  situated  in 
the  pelvic  cavity,  the  internal  surface  of  the 
posterior  and  inferior  portion  of  the  organ. 
The  researches  of  anatomists  have  most  posi- 
tively confirmed  these  indications,  by  shewing 
that  in  extroversion  of  the  bladder  the  anterior 
part  of  this  organ  is  more  or  less  completely 
wanting,  and  that  the  posterior  part  is  pushed 
from  behind  forwards,  through  the  large  open- 
ing which  results  from  this  absence,  causing 
a  "  hernia"  either  between  the  two  pubes 
and  the  two  recti  muscles,  or,  which  is  veiy 
rare,  only  between  the  latter,  the  mucous  mem- 
brane being  presented  externally.  By  this 
displacement  the  external  posterior  surface  of 
the  bladder  forms  a  concavity  in  which  some 
portions  of  the  intestinal  tube  may  be  impacted, 
as  in  a  true  herniary  sac,  especially  when  the 
abdominal  muscles  and  the  diaphragm  are 
strongly  contracted.  The  volume  of  the  tu- 
mour is  on  this  account  variable,  not  only  as 
between  one  subject  and  another,  but  in  the 
same  subject  at  different  ages.  Thus  in  new- 
born infants  only  a  slight  projection  is  presented: 
the  tumour  may  not  occupy  a  larger  space 
than  from  half  an  inch  to  an  inch.  In  adults 
it  may  project  to  the  extent  of  two  or  more 
inches  and  present  a  transverse  diameter  of 
four  or  five.  The  tumour  is  then  smooth  and 
frequently  appears  divided  into  two  lobes. 

When  extroversion  of  tlie  bladder  exists,  the 
umbilicus  commonly  is,  as  in  the  embryo  and 
the  young  foetus,  not  far  removed  from  the 
symphysis  pubis,  nor  consequently  from  the 
vesical  tumour.  The  umbilicus  is  almost 
always  found  immediately  above  the  tumour. 
Sometimes,  however,  the  superior  extremity  of 
the  latter  is  observed  beyond  the  umbilicus, 
which  is  then  entirely  concealed ;  and  in  con- 

*  Acad.  dcs  Sciences,  1761,  torn.  cxiv.  iu  12ino. 
p.  67. 


sequence  of  this  circumstance,  some  author 
have  believed  that  the  umbilicus  was  not  pre- 
sent in  infants  affected  with  extrophy,  and  they 
have  drawn  from  this  fancied  absence  phy- 
siological consequences  as  erroneous  as  the 
facts  upon  which  they  were  based  are  ground- 
less. 

This  affection  was  until  recently  supposed 
to  occur  only  very  rarely  in  the  female ;  this 
opinion,  however,  is  incorrect.  In  many  of 
the  cases  on  record  the  sex  is  not  specified, 
and  it  is  not  improbable  that  many  women 
may  from  a  sense  of  shame  be  desirous  of 
concealing  such  a  disgusting  deformity.  Even 
with  these  reasons  why  the  cases  should  be  less 
numerous,  we  have  been  enabled  to  collect 
twenty -one  examples.  In  women  the  affection 
does  not  produce  so  much  derangement  in  the 
sexual  functions  as  when  it  exists  in  man, 
by  whom,  the  penis  being  almost  constantly 
deprived  of  urethra,  fecundation  must  be  al- 
most impossible.  In  the  other  sex,  on  the 
contrary,  the  vagina  being  ordinarily  free, 
though  more  or  less  contracted,  coitus  may 
have  place,  as  in  a  well  conformed  female, 
and  fecundation  may  follow,  as  in  the  case 
detailed  by  Drs.  Huxham  and  Oliver  and  Mr. 
Bonnet,  of  a  woman  who  lived  at  Lantglasse 
near  Fowey  ;*  and  that  of  Thiebault,  in  which 
the  delivery  occurred  through  the  perineum. 
Among  the  anatomical  varieties  by  which  it  is 
accompanied,  none  are  more  singular  than  that 
mentioned  by  Bartholin,f  in  which  there  was 
neither  anus  nor  penis,  all  the  ingesta  return- 
ing from  the  mouth  during  forty  years. 

It  has  been  over  and  over  again  maintained 
that  this  affection  was  incompatible  with  long 
life.  The  child  of  which  Ilighmore  speaksj 
was  ten  years  old,  and  in  good  health ;  the 
case  of  which  Montagne  speaks§  was  at  the 
time  a  person  of  thirty ;  that  of  Flajani  || 
was  seventy.  Baillie,^  Mowatt,**  Innes,ff 
and  Labourdette,{|  all  describe  the  cases  of 
adults.  Quatrefages  §§  describes  the  cases  of 
a  person  of  forty-nine  and  of  another  of  forty- 
six. 

Most  authors  who  have  written  on  this  sub- 
ject have  strenuously  maintained  the  constancy 
of  the  separation  of  the  bones  of  the  pubis. 
Duncan,  even  in  spite  of  the  case  of  Mr. 
Coates,  with  the  details  of  which  he  was  fami- 
liar, retained  that  opinion  apparently  unshaken. 
We  are  in  possession  of  the  particulars  of 
cases  in  which  no  such  separation  existed,  re- 
corded by  Coates,j|||  Denman,  Roose,^I1[ 

*  Phil.  Transact,  vol.  xxiii.  1723,  p.  408,  413, 
and  vol.  xxxiii.  p.  142. 

t  Hist.  Airit.  cent.  iv.  hist.  30,  p.  293. 

t  Disquis.  Anat.  pnrt  iv.  cap.  7. 

$  Acad.  dcs  Sciences,  tome  cxiv.  in  12mo. 
p.  67. 

||  Malattic  Spcttanti  alia  Chirurg.  1786. 

f   Morbid  Anat.  p.  309. 

"*  Mem.  de  Desgrnngcs. 

ft  Arch.  Gincr.  voCii.  p.  286. 

Jt  Journal  de  Scdillot. 

§§  Theses  dc  Strasbourg,  4to.  1832. 

i!||  Edinburgh  Med.  and  Sure.  Journal,  vol.  i. 

5f1f  De  native  vesicae  urinariae  iuvers.  <N:C. 
p.  19. 


BLADDER,  ABNORMAL  ANATOMY. 


Walther,  and  one  of  Quatrefages;*  and  there 
are  still  one  or  two  others,  about  which  some 
doubt  exists.  What  proportion  these  cases 
would  bear  to  those  in  which  the  separation 
was  demonstrated,  it  is  almost  impossible  to 
determine,  because  there  can  be  no  doubt  that, 
of  the  numerous  recorded  cases,  many  of  the 
descriptions  appertained  to  the  same  indivi- 
dual, the  total  number  of  cases  being  in  my 
opinion  much  less  than  is  supposed.  It  is 
easy  to  explain  how  this  source  of  error  has 
been  introduced.  The  unfortunate  persons 
who  are  subjected  to  this  infirmity  are  often 
objects  of  general  curiosity.  They  wander 
from  town  to  town  for  the  purpose  of  obtaining 
a  livelihood  by  exhibiting  themselves  to  me- 
dical societies  and  to  private  individuals,  and 
the  history  of  a  single  person  may  thus  be 
found  repeated  in  the  different  periodicals  of 
the  same  and  even  of  different  countries. 

To  determine  the  mode  in  which  this  vice  of 
conformation  is  effected  is  very  difficult.  We 
cannot  admit  that  Duncan'sf  explanation  of  the 
mode  of  its  formation  is  correct,  because  it  is 
opposed  to  every  principle  which  we  are  ac- 
customed to  recognize  as  presiding  over  the 
developement  of  our  organs.  He  attempted 
to  prove  that  an  obstacle  to  the  expulsion  of 
urine  affords  a  satisfactory  explanation  of  this 
phenomenon,  and  he  believed  that  the  bladder, 
by  its  distention,  removes  the  bones  of  the 
pubis  from  each  other,  ruptures  the  hypogas- 
trium,  and  then  disorganises  itself.  We  should 
have  conceived  that  a  very  little  reflexion  would 
have  removed  from  his  mind  so  singular  an 
opinion.  The  disease  is  almost  always  conge- 
nital, although  during  intra-uterine  life  the 
fetus  can  have  but  little  urine  to  void,  and 
cannot,  consequently,  have  a  distended  blad- 
der. Duncan  himself,  however,  strangely 
enough  states  the  case  of  a  little  boy  who  was 
affected  by  the  disease,  although  the  urethra, 
placed  in  front  of  the  root  of  the  penis, 
strongly  curved  towards  the  anus,  allowed  of 
the  easy  passage  of  the  renal  secretion.  And 
there  are  cases  on  record  well  authenticated, 
where  no  separation  of  the  pubis  existed. 
Isenflamm  also  states  that  the  disease  was 
manifested,  in  his  experience,  ten  weeks  after 
birth.  The  opinion  of  Duncan,  therefore, 
cannot,  it  is  apprehended,  be  sustained. 

Those  persons  who  believe  this  disease  to  be 
a  primitive  monstrosity  are  divided  into  two 
classes.  The  one  suppose  it  to  be  merely  an 
organic  deviation,  in  which  the  urethra  is 
placed  above  instead  of  gliding  beneath  the 
pubis.  This,  however,  is  not  the  prevailing 
doctrine;  that  which  has  obtained  the  most 
general  currency  is  based  upon  the  theory  of 
arrested  development.  Supposing  that  the 
two  moieties  of  the  body  do  not,  until  late, 
meet  upon  the  median  line  anteriorly,  they 
say,  if,  by  any  cause,  the  sides  of  the  hypo- 
gastric  parietes  cease  to  advance,  the  one  to- 
wards the  other,  during  their  allotted  time, 
the  bladder  will  pass  between  them,  and  will 

*  Theses  de  Strasbourg,  1832. 

t  Edinburgh  Med.  and  Surg.  Journal  for  1805 


soon  lose  its  anterior  moiety,  supposing  this 
moiety  to  be  already  formed,  from  whence  the 
fungous  state  which  it  offers  after  birth.  So 
powerful  are  the  authorities  by  which  this  mode 
of  explaining  the  phenomena  is  supported,  so 
completely  is  it  said  by  the  ardent  supporters 
of  teratology  to  be  in  consonance  with  its 
principles,  that  it  would  appear  to  be  almost 
heretical  to  support  a  somewhat  different  view 
of  the  subject  taken  by  M.  Velpeau.  He  be- 
lieves that  extrophy  of  the  bladder  is  not 
simply  owing  to  an  arrested  development, 
first,  because  in  the  normal  state  the  bladder 
is  neither  split  nor  open,  neither  anteriorly  nor 
posteriorly;  secondly,  because  the  pubic  circle 
is  completely  formed  before  the  bladder  is  per- 
ceptible; thirdly,  because  the  aspect  of  the 
fissure  that  the  urinary  sac  should  present 
never  exists;  and,  fourthly,  because  the  theory 
in  question  has  for  its  support  only  such  ana- 
logies as  do  not  appear  to  us  to  have  been 
completely  established.  If  an  hypothesis  be 
required,  it  appears  to  be  more  in  conso- 
nance with  observation  to  assume  that  this 
vice  depends  upon  an  alteration  of  the  abdo- 
men, either  pathological  or  purely  mechanical, 
contracted  during  embryo  life.  The  parietes 
of  the  abdomen  are  extremely  attenuated  and 
fragile  up  to  between  the  second  and  third 
months,  and  for  some  time  beyond  this  the 
parietes  do  not  acquire  any  thing  like  the 
density  below  that  they  do  above  the  umbilicus. 
At  this  time  the  space  is  so  small  between  the 
umbilicus  and  the  sexual  organs,  that  the 
smallest  fissure  may  become  the  origin  of  a 
large  ulceration,  and  such  lesions  are  seen  at 
all  degrees.  Indeed  it  is  scarcely  possible  to 
set  forth  the  variety  of  lesions  to  which  the 
young  fcetus  is  subject :  foetuses  have  been 
seen  in  which  the  parietes  of  the  abdomen 
were  alone  destroyed.  In  one  of  three  months 
the  bladder  was  already  comprised  in  such  a 
perforation,  and  the  borders  of  the  whole  weie 
so  jagged,  thin,  and  unequal,  that  it  could  be 
referred  to  nothing  else  than  a  laceration.  It 
is  held  in  this  place,  therefore,  that  extrophy  is 
frequently  a  disease,  or  the  effect  of  a  diseases, 
but  not  a  monstrosity ;  an  ulceration,  a  perfo- 
ration of  the  penis  or  of  the  hypogastrium, 
being  the  common  point  of  origin.  The 
bladder  is  only  secondarily  altered.  If  the 
fcetus  continues  to  live,  the  borders  of  the  de- 
stroyed bladder  are  united  to  the  circumference 
of  the  abdominal  opening,  or,  at  least,  to  the 
posterior  surface  of  the  remaining  portion  of 
the  hypogastrium.  The  cicatrisation  once  ef- 
fected, the  rest  is  explained  by  the  mucous 
nature  of  the  organic  septum,  which  occupies 
the  place  of  the  pelvic  or  abdominal  parietes. 
The  umbilicus  may  or  may  not  be  implicated 
in  the  loss  of  substance ;  the  pubes,  which  are 
commonly  destroyed,  and  not  simply  sepa- 
rated as  has  been  believed,  may  be  also  pre- 
served ;  and  the  vesical  tumour  may  in  some 
cases  only  occupy  a  space  of  a  few  lines, 
whilst  in  others  it  may  implicate  a  great  por- 
tion of  the  hypogastrium. 

Those  organs  which  are  normally  in  relation 
with  the  pubis  present   certain  anomalies   in 


BLADDER,  ABNORMAL  ANATOMY. 


393 


extroversion  of  the  Madder,  which  should  be 
mentioned  in  this  place.  The  ureters,  of 
course,  open  immediately  upon  the  surface  of 
the  body  ;  the  urethra  no  longer  serves  for  the 
emission  of  mine,  and  is  often  incomplete. 
Commonly  in  woman  it  opens  above  the  cli- 
toris, in  rnan  above  the  penis.  Occasionally 
the  testicles  do  not  descend.  Meckel  has 
remarked  that  there  is  commonly  a  separation 
of  the  two  lateral  moieties  of  the  external 
genital  organs,  like  that  of  the  abdominal 
muscles  and  the  pubis.  It  has  been  remarked 
by  Duncan  (loc.  cit.)  that  this  infirmity  more 
commonly  happens  to  the  male  than  the  female. 
Meckel  doubts  this  proposition,  and  adds  many 
cases  to  those  cited  by  Duncan,  in  which  the 
disease  affected  the  female.  Isidore  Geoffrey 
St.  llilaire,  who  has  carefully  examined  the 
recorded  cases,  which  are  now  very  numerous, 
supports  the  conclusion  of  Duncan  :  he  says 
that  of  these  one-fourth  appertain  to  females, 
nearly  two-thirds  to  males,  and  in  the  re- 
mainder the  sex  was  undetermined.  Ex- 
trophy  of  the  bladder  is  a  very  serious  af- 
fliction, because  of  the  incontinence  of  urine 
which  is  its  inevitable  consequence,  and  the 
deformity  of  the  genital  organs  by  which  it  is 
constantly  accompanied,  and  which,  in  man 
especially,  very  commonly  occasions  impo- 
tence. It  constitutes  a  more  serious  disease  in 
the  male  than  in  the  female,  for  in  the  latter 
the  external  genital  organs,  except  the  want  of 
projection  of  the  pubic  eminence,  commonly 
suffer  only  slight  modifications  of  form  :  the 
ovaries,  the  uterus,  and  their  appendages  may 
not  even  present  any  anomalies.* 

PenUtance  of  the  urachus. — The  last  of 
the  congenital  malformations  to  which  I  shall 
allude  is  the  persistance  of  the  urachus  some- 
times even  to  adult  age.  For  a  considerable 
time  much  doubt  was  expressed  whether  the 
urachus  was  ever  a  canal,  pervious  from  the 
bladder  to  the  umbilicus  ;  and  it  was  not  gene- 
rally admitted  until  the  fact  had  been  re- 
peatedly demonstrated  by  Haller  and  his  pupil 
Noreen.  In  January,  1787,  Boyer  exhibited 
a  bladder  taken  from  a  man  aged  thirty-six,  in 
which  the  urachus  formed  a  canal  an  inch  and 
a  half  long,  and  containing  twelve  urinary 
calculi,  each  of  the  size  of  a  millet-seed;  and 
it  was  demonstrated  that  this  canal  was  not  a 
vesical  sac  or  a  prolongation  of  the  mucous 
membrane.  But  these  cases  of  persistance  of 
the  cavity  of  the  urachus  in  adult  or  even  in 
infant  life  are  unquestionably  extremely  rare ; 

9  For  more  minute  details  of  this  affection  the 
reader  may  consult  Blasius,  part  iv.  obs.  6.  Stal- 
part  Vanderwiel,  vol.  ii.  p.  56.  Bartholin,  cent, 
ii.  hist.  65,  the  Edinburgh  Essays,  vol.  iii.  p.  257, 
the  Journal  Encyclopcdique,  August,  1756,  the 
Journal  de  Medecine  of  Paris,  t.  v.  p.  108,  et  t. 
xxvii.  p.  26,  the  Memoirs  of  the  Academy  of  Sci- 
ences of  Paris,  1761,  where  we  find  an  observation 
of  Lemery  made  in  1741,  and  three  facts  observed 
by  Tenon,  also  the  second  volume  of  Medical 
Commentaries  by  a  Society  of  medical  men  at 
Edinburgh,  p.  437,  and  the  Memoirs  of  Duncan 
(Edinb.  Mod.  and  Sarg.  Journ.  1805),  and  Velpeau 
(Mem  dc  1'Acad.  Royalc  de  Med.  loin,  iii.) 


and  it  is  certain  that  a  protrusion  of  the  mu- 
cous tunic  in  the  form  of  a  canal  at  this 
point  has  been  mistaken  for  the  canal  of  the 
urachus  ;  it  is  even  probable  that  generally 
where  the  urine  is  prevented  from  escaping  by 
the  urethra,  and  where  it  escapes  by  the  umbi- 
licus, it  results  from  the  rupture  of  the  species  of 
hernia  formed  near  the  situation  of  the  urachus 
by  the  mucous  tunic  of  the  bladder,  and  not 
from  the  dilatation  of  this  membranous  cord. 

When  this  canal  remains  pervious  only  in  a 
part  of  its  extent,  the  anomaly  is  not  indicated 
externally.  When  its  cavity  is  preserved  even 
from  the  bladder  to  the  umbilicus,  nothing 
marks  its  existence  at  the  exterior  if  the  urinary 
passages  are  unobstructed ;  in  the  opposite 
condition  a  very  remarkable  physiological  ano- 
maly accompanies  it,  and  reveals  the  presence 
of  the  anatomical  anomaly;  it  is  the  total  or 
partial  excretion  of  urine  by  the  umbilicus, 
either  constantly  and  from  the  moment  of 
birth,  which  is  the  case  when  a  vice  of  confor- 
mation or  a  disease  prevents  the  urine  from 
passing  by  its  natural  channel  ;*  or  tempo- 
rarily, when  the  course  of  the  urine,  which 
was  at  first  by  the  urethra,  comes  to  be  inter- 
rupted by  any  cause. 

Sigismund  Konigf  relates  the  case  of  a 
woman  in  whom  the  urine,  usually  excreted 
by  the  urethra,  passed  by  the  umbilicus  during 
some  days  in  consequence  of  a  severe  labour ; 
but  this  example  and  others  which  might  be 
mentioned  do  not  appear  to  possess  the  authen- 
ticity which  is  required  to  establish  that  this 
infirmity  may  be  acquired.  It  is  probable 
that  many  of  these  cases  were  simply  a  hernia 
of  the  mucous  membrane  of  the  bladder,  such 
as  occurred  in  the  case  detailed  by  Portal  4 

ACQUIRED  CHANGES. 

Sacculi  or  cysts. — A  sacculated  or  encysted 
condition  of  the  bladder  is  never  a  congenital 
vice  of  conformation  of  that  organ,  but  an 
effect  of  disease.  Sacculi  may  be  produced 
by  any  thing  which  can  oppose  itself  to  the 
excretion  of  urine,  or  which  may  enfeeble  the 
muscular  tunic  of  the  organ.  In  this  way  the 
urine  becomes  collected  in  the  bladder,  the 
parietes  are  distended,  the  internal  tunic  is 
forcibly  applied  upon  the  muscular  coat,  and 
if  at  any  point  this  tunic  be  weakened,  less 
resistance  is  offered,  a  separation  between  some 
of  its  fasciculi  takes  place  to  a  sufficient  dis- 
tance to  admit  of  the  mucous  membrane  pass- 
ing between  them,  and  in  this  way  sacculi 
may  be  formed. 

This,  however,  is  not  the  only  way  by  which 
this  state  may  be  produced  ;  in  some  bladders 
the  muscular  tunic  is  so  developed,  probably 
by  irritation,  that  its  fasciculi  are  grouped  and 
a  columnar  aspect  is  produced,  not  very  unlike 
to  the  appearance  of  the  interior  of  the  ven- 
tricles of  the  heart. 

*  Littre,  Mem.  de  1'Acad.  des  Sciences,  1701,  p. 
23.  Sabatier,  Traite  d'Anat.  t.  ii.  p.  402,  et  t.  iii. 
p.  498.— Cabrol,  Alphabet  Anat.  obs.  20.  This 
case  occurred  at  Beaucairc  in  1550. 

t  Phil.  Trans,  v.  16. 

t  Mem.  de  1'Acad.  des  Sciences,  1769. 


394 


BLADDER,  ABNORMAL  ANATOMY. 


Certain  portions  of  the  parietes  of  the  organ 
are  in  such  cases  unprovided  with  the  muscular 
fibre  necessary  to  enable  them  to  offer  the 
usual  resistance,  and  a  similar  effect  is  pro- 
duced to  that  which  I  have  already  described, 
the  mechanism  being  somewhat  different. 

These  sacs  may  attain  great  size,  even  supe- 
rior to  that  of  the  bladder  itself;  commonly 
the  point  by  which  communication  with  the 
bladder  is  maintained  is  only  a  narrow  neck, 
and  in  consequence  of  this  circumstance  the 
organ  has  occasionally  been  described  as  dou- 
ble, triple,  and  so  on.  It  is  always  easy  to 
determine  whether  it  be  really  so  or  not,  first, 
by  examining  the  parietes  of  each,  and, 
secondly,  by  ascertaining  the  points  at  which 
the  ureters  are  implanted.  In  the  first  case  we 
shall  find  only  one  of  these  compartments 
invested  by  a  muscular  tunic :  in  the  second 
an  ureter  has  never  yet  been  known  to  pene- 
trate directly  the  adventitious  cavity. 

There  is  scarcely  any  point  of  the  surface  of 
the  bladder  in  which  such  a  state  may  not  be 
produced,  but  there  are  certain  regions  where 
the  affection  is  much  more  frequently  met  with 
than  others.  They  are  most  commonly  formed 
at  the  lateral  parts,  or  at  the  summit,  near 
the  insertion  of  the  urachus.  Occasionally 
many  of  these  sacculi  are  found  in  the  same 
bladder.* 

A  species  of  sacculi  or  appendices  may, 
however,  be  produced  by  an  extension,  at  a 
given  point,  of  the  whole  of  the  vesical  tunics ; 
and  even  these  may  be  a  consequence  of  re- 
tention of  urine,  but  more  frequently  of  the 
sojourn  of  a  stone,  which  forms  a  cell. 
Some  examples  of  this  species  are  given  by 
Morgagni.f  A  woman,  two  years  before  her 
death,  introduced  into  the  urethra  "  a  long  hair 
pin ;"  this  instrument  slipped  from  her  grasp 
and  passed  into  the  bladder,  where  it  became 
arranged  transversely,  so  that  whilst  the  point 
rested  upon  the  left,  its  head  rested  on  the 
right  side  of  the  organ.  The  head  became 
incrusted  with  calcareous  matter;  a  stone  of 
the  size  of  a  nut  was  thus  formed,  which  was 
contained  in  a  quadrilateral  sac  produced  by 
the  extension  of  the  whole  of  the  tunics  of  the 
bladder. 

Cells  or  cysts  may  be  otherwise  formed  at 
the  expense  of  the  vesical  parietes.  Calculous 
concretions  may  be  formed  in  the  kidney,  and 
may  pass  unobstructed  through  the  ureter  into 
the  bladder;  but  if  the  magnitude  of  the  stone 
be  disproportioned  to  the  capacity  of  the  canal 
of  the  ureter,  it  may  sojourn  at  any  point  of  the 
continuity  of  this  canal,  or  at  the  point  where 
it  terminates  in  the  bladder.  If  also  the  cal- 
culous  matter  be  abundant  in  the  urine,  it  will 
be  deposited  upon  this  nucleus,  which  will  more 
or  less  rapidly  augment  in  volume,  and  will 
be  impacted  at  or  near  the  point  where  it  may 
have  acquired  this  augmentation.  The  first 
author  who  speaks  in  a  clear  and  precise  man- 
ner of  this  affection  is  the  celebrated  Pierre 

*  Hcistcr. 

t  De  Sed.  &c.  op.  xlii.  art.  18. 


Franco.*  Since  Franco,  it  has  been  described  by 
by  many  others,  particularly  by  Alexander  Mon- 
rof  and  Iloustet.J  The  existence  of  this  affection 
is  certainly  not  frequent,  but  its  occasional  occur- 
rence is  amply  proved :  formed  in  the  way  I 
have  described,  these  calculi  occasionally  glide 
between  the  mucous  and  muscular  tunics  of  the 
organ  by  means  of  an  opening  which  they  form 
at  the  point  where  the  ureter  obliquely  pierces 
the  bladder,  instead  of  entering  the  bladder  by 
the  natural  channel.  The  volume  of  these  cysts 
is  never  very  considerable,  for  such  calculi  do 
not  acquire  anything  like  the  volume  of  those 
which  are  commonly  found  moving  freely  in  the 
cavity  of  the  bladder.  The  reason  of  this  is  ob- 
vious ;  they  are  not  exposed  to  the  action  of  any 
considerable  quantity  of  urine,  and  they  cannot 
consequently  receive  a  large  accession  of  calcu- 
lous  matter.  Covillard§  and  Garengeot||  have 
seen  them  of  the  size  of  a  hen's  egg,  but  such 
cases  are  rare.  Commonly  they  are  very  little 
removed  from  the  insertion  of  the  ureters.  The 
reason  of  this  is  not,  however,  that  which  was 
assumed  by  Littre,«[[  because  the  contraction  of 
the  muscular  fibres  is  made  towards  the  fundus, 
and  that  in  consequence  the  calculus  would  be 
forced  to  wards,  that  region,  but  by  reason  of  the 
resistance  offered  by  the  membrane  of  the  cyst 
by  which  they  are  surrounded. 

CHANGES    OF    CAPACITY. 

The  bladder  may  suffer  certain  modifications 
of  capacity  as  consequences  of  disease.  It  may 
become  so  distended  as  to  contain  nine  pounds 
of  urine  (in  puella  pro  hydropica  habita, 
Koenig)**  novem  chopines  ab  ischuria,  La 
Motte;)ff  or  even  twelve  pounds,  Felix  Pascal: 
or  it  may  become  so  diminished  that  its  volume 
shall  not  exceed  that  of  a  small  walnut.  In 
1764,  M.  Portal  found  at  Montpellier,  in  the 
dead  body  of  a  woman  aged  sixty,  the  bladder 
so  small  that  its  volume  did  not  exceed  that  of 
a  hazel-nut. 

Decrease. — In  persons  who  pass  urine  fre- 
quently, the  bladder  is  small ;  still  more  so  in 
those  whose  kidneys  do  not  perform  their  func- 
tions properly.  It  is  small  in  those  cases  of 
irritation  by  which  frequent  contractions  are 
excited.  Lithotomists  have  frequently  remarked 
that  in  calculous  patients  the  bladder  closely 
embraced  the  stone.  Morgagni,  JJ  in  opening 
the  body  of  a  girl  of  fourteen,  found  the  bladder 
adherent  to  the  parietes  of  the  abdomen  imme- 
diately above  the  pubis,  and  so  contracted 
around  a  needle,  which  had  been  introduced 
sixteen  months  before  her  death,  that  this  viscus 
could  scarcely  have  contained  anything  more. 


*  Traite  des  hernies.  chap.  xxxi.  p.  107,  Lyon, 
1561. 

t  Essays  and   Observations  of  the  Medical   So- 
ciety of  Edinburgh,  vol.  vi.  p.  257. 

$  Mem.  dc  1'Acad.  dcs  Sciences  de  Paris,  ana. 
1702. 

Obs.  11. 

Mem.  de  1'Acad.  de  Chir.,  t.  i.  p.  411. 
Mem.  de  1'Acad.  des  Sciences,  an  1702. 
**  Lith.  spec.  Epist.  11. 
ft  Trait6  dcs  Accouchmens,  Obs.  44. 
U  De  Sed.  ep.  xlii.  art.  20. 


BLADDER,  ABNORMAL  ANATOMY. 


395 


The  bladder  is  also  very  small  in  cases  of 
incontinence  of  urine  and  in  vesical  fistula*. 

Increase. — The  volume  of  the  bladder  aug- 
ments when  the  whole  or  a  great  portion  of 
the  urine  is  retained  in  its  cavity,  and  under  the 
opposite  conditions  to  those  which  have  just 
been  named.  To  such  an  extent  may  this  in- 
crease proceed,  that  it  may  be  mistaken  for 
ascites.*  Inflammation  of  the  bladder  com- 
monly accompanies  its  excessive  dilatation, 
but  many  circumstances  related  by  Morgagni 
and  others  prove  that  this  viscus  may  be  con- 
siderably distended  by  urine  without  becoming 
inflamed.  It  may,  however,  lose  its  contractile 
power,  and  the  assistance  of  art  may  be  neces- 
sary for  the  evacuation  of  the  urine.  A  fact 
stated  by  Mauchartf  shews  that  a  man  had 
ischuria,  which  had  commenced  four  days  before 
he  was  sounded.  Some  days  after  this  he  died; 
the  bladder  was  found  inflamed  in  different 
points.  It  was  entirely  empty  and  yet  very 
voluminous,  without  being  contracted  as  it  is 
commonly  after  death. 

Introversion, — Among  the  acquired  changes 
of  conformation  of  the  urinary  bladder,  there 
is  one  which  may  be  termed  introversion.  In 
this  affection,  which  is  rare,  the  superior  por- 
tion of  the  organ  is  so  depressed  as  to  be  brought 
near  to  its  neck,  to  project  into  the  urethra, 
and  in  woman  to  make  its  appearance  at  the 
external  orifice  of  that  canal.  Chopart  J  relates 
from  Percy  the  following  observation : — The 
patient  was  an  abbess  aged  fifty-two,  in  whom 
the  fundus  of  the  bladder  was  impacted  in  the 
neck,  having  also  passed  along  the  urethra, 
and  forming  at  its  external  orifice  a  tumour  of 
the  volume  of  the  eye  of  a  pigeon,  red,  fleshy, 
unequally  tumefied,  which,  when  pressed  upon 
with  the  finger,  returned  into  the  canal  and 
reappeared  without  any  violent  exertion.  An 
analogous  case  occurred  to  Foubert.§  The 
patient  died,  the  body  was  examined  after 
death,  and  it  was  found  that  the  posterior  and 
superior  region  of  the  bladder  was  depressed 
into  the  form  of  a  cone  whose  apex  had  pene- 
trated the  neck  of  the  bladder,  a  portion  of 
ileum  about  six  inches  long  being  lodged  in 
this  depression. 

When,  in  the  female,  the  summit  of  the 
bladder  is  engaged  in  the  neck,  the  simple 
inspection  of  the  tumour,  its  increase  after 
walking  or  in  consequence  of  a  fit  of  coughing, 
its  disappearance  with  compression,  are  sym- 
ptoms sufficient  to  enable  us  to  recognize  the 
disease.  Those  aged  persons  whose  bladders 
are  very  capacious,  and  who  are  become  feeble, 
are  most  subject  to  this  affection,  which  is 
produced  by  the  pressure  which  the  other 
viscera  exercise  on  this  organ. 

Hernia. — The  absence  of  information  in  old 
authors  on  the  subject  of  hernial  displacement 
of  the  urinary  bladder  induced  an  opinion 
which  was  current  for  very  many  years,  that  the 


*  Chopart,  Smcllie,  Black. 
t  Ephcmerides  Acad.  Nat.  Cur.,  cent.  ix.  obs.  41. 
J:  Traite  dos  Maladies  dcs  Voics  Urinaircs.  t.  i. 
D.  399.  Edit.  1830. 
§  Mem.  de  1'Acad.  dc  Chir.,  t.  ii,  p.  36. 


affection  we  are  about  to  consider  was  of  ex- 
tremely unfrequent  occurrence.  This,  however, 
is  an  erroneous  opinion,  for  the  experience  of 
modem  times  has  demonstrated,  that  though 
less  frequent  than  hernia  of  the  intestines  or  of 
the  epiploon,  cystocele  is  not  an  unfrequent 
disease.* 

The  inguinal  ring,  the  crural  arch,  the  peri- 
neum, and  the  anterior  walls  of  the  vagina 
may  become  the  seat  of  a  hernia  of  the  blad- 
der. At  whichever  of  these  points  the  disease 
may  be  manifested,  the  bladder,  fixed  deep  in 
the  pelvis  and  hidden  behind  the  pubes,  is 
never  completely  displaced;  only  prolongations 
of  the  organ  can  pass  these  several  points.  It 
must  be  at  once  evident  that  besides  the  dila- 
tation of  the  opening  through  which  it  passes, 
there  must  be  a  great  increase  in  the  capacity 
of  the  organ  itself,  and  a  great  relaxation  of 
its  parietes,  occasioned  most  commonly  by 
retention  of  urine,  or  by  a  habit  of  only  rarely 
attending  to  a  desire  for  its  evacuation.  Whe- 
ther the  protrusion  occur  at  the  one  or  the  other 
of  the  several  regions  I  have  named,  there  are 
certain  general  characters  by  which  it  may  be 
more  or  less  readily  detected.  We  shall  find 
a  soft  tumour,  accompanied  by  a  fluctuation 
which  is  as  much  more  sensible,  and  which 
acquires  a  volume  as  much  more  considerable 
as  the  time  which  may  have  elapsed  without 
an  evacuation  of  urine  is  greater.  This  tumour 
may  be  easily  lessened  by  compression,  but 
the  reduction  is  immediately  followed  by  an 
urgent  desire  to  pass  the  urine. 

This  species  of  hernia  is  only  partially  co- 
vered by  peritoneum.  Dominique  Sala  is, 
according  to  Bartholin,f  the  first  person  who 
mentioned  this  peculiarity.  The  reason  of  this 
circumstance  is  obvious :  when  the  bladder  is 
distended,  it  is  raised  to  the  level  of  the  crural 
arch  and  of  the  inguinal  ring ;  it  pushes  before 
it  the  peritoneum,  and  insinuates  itself  between 
the  peritoneum  and  the  abdominal  muscles. 
If  at  this  time  a  violent  effort  determine  the 
escape  of  the  corresponding  part  of  the  organ 
by  one  or  other  of  these  openings,  it  is  the 
anterior,  superior,  and  lateral  part  of  the 
organ  which  will  be  presented,  and  this  is  the 
portion  which  is  without  a  peritoneal  invest- 
ment; so  that  at  this  time  the  herniae  we  have 
described  are  completely  deprived  of  a  sac. 
It  usually  happens,  however,  that  the  posterior 
portion  of  the  organ  soon  follows,  dragging 
with  it  the  peritoneum  by  which  it  is  covered; 
this  portion  in  turn  drags  down  that  which  is 
in  the  vicinity  of  the  ring;  and  in  this  way  a 
hernial  sac  is  formed,  ready  for  the  reception  of 
the  intestine  or  the  omentum.  This  is  the 
reason  why  a  hernia  of  the  bladder  is  so  fre- 
quently accompanied  by  an  intestinal  or  omen- 
tal  hernia. 

*  For  a  confirmation  of  this  opinion,  see  Blegny, 
Traite  des  Hernics,  1688;  Mcry,  Mem.  de  1'Acad. 
des  Sciences,  1713;  Petit,  memo  onvrage,  1717; 
Le  Dran,  Garcngcot,  and  La  Faye.  Hcister  and 
Plainer,  Instit.  Chir.  J.  G.  Gunzii,  Obs.  an.  Chir. 
de  Hernia,  Lipsitc,  1744  ;  Monro,  Levrct,  Sharp, 
Pott,  Scaipa,  Lawrence,  and  others. 

t  Hist.  Anat.,  cent,  xviii. 


39C 

It  does  not  appear  to  be  well  established 
whether  a  primitive  hernia  of  the  bladder 
occurs  in  the  direction  of  the  inguinal  canal, 
or  whether  it  escapes  directly  through  the 
aponeurotic  opening  of  the  external  abdominal 
muscle,  though  the  latter  opinion  is  the  most 
probable.  It  has  been  remarked  in  some  cases 
that  the  spermatic  vessels  were  external  to  the 
hernia. 

In  consecutive  vesical  hernia  an  intestinal 
hernia  primarily  exists;  the  intestine  pushes 
before  it  the  peritoneum  which  surrounded  the 
ring,  and  in  proportion  as  the  hernia  increases 
in -volume,  does  the  sac  augment,  the  peri- 
toneum in  the  neighbourhood  of  the  ring  is 
drawn  down,  and,  as  a  consequence,  that  which 
invests  the  posterior  surface  of  the  bladder,  which 
in  its  turn  is  also  drawn  down,  if,  on  the  one 
hand,  the  adherence  of  the  peritoneum  to  the 
bladder  be  sufficiently  strong,  and  if,  on  the 
other,  the  latter  organ  be  voluminous  and  sus- 
ceptible of  displacement.  The  primitive  peri- 
rieal  and  vaginal  herniae  are  similarly  situated 
as  to  the  non-existence  of  a  hernial  sac,  and  of 
the  existence  of  consecutive  hernia  in  these 
situations  we  have  no  record. 

The  species  of  vesical  hernia  which  is  most 
commonly  seen  is  the  inguinal ;  the  tumour  is 
usually  confined  to  the  groin,  but  it  may 
descend  into  the  scrotum,  gliding  along  the 
spermatic  cord.* 

Hernia  of  the  bladder  at  the  crural  ring  is 
very  rare.  It  presents  the  same  characters  and 
is  subject  to  the  same  complications  as  that 
which  occurs  at  the  inguinal  ring.  Its  form 
and  its  seat  only  are  different;  it  is  developed 
at  the  same  point  as  a  merocele,  and  like  it 
takes  a  globular  form. 

Vesical  hernia  at  the  perineum  is  an  ex- 
tremely rare  disease,  and  for  some  time  was 
supposed  to  occur  exclusively  in  pregnant 
women,  but  the  observation  of  Pipelet  is  con- 
clusive as  to  the  possibility  of  its  existence  in 
man.  In  these  cases  a  portion  of  the  bladder 
passes  between  the  fibres  of  the  levator  ani 
muscle,  and  it  is  presented  in  the  form  of  an 
ovoid  tumour  placed  at  the  side  of  the  anus. 
In  each  of  the  three  species  of  hernia  which 
we  have  described,  the  bladder  suffers  certain 
changes  of  form :  it  is  contracted  at  the  level  of 
the  opening  through  which  it  passes,  and  is  again 
dilated  below  this  point.  This  circumstance 
lias  been  observed  by  Keate,  Pott,  and  Ber- 
trandi.  Sometimes  even  calculi  have  been 
found  in  the  displaced  portion  of  the  blad- 
der.f 

Few  occasions  have  occurred  of  observing 
hernia  of  the  bladder  through  the  vagina.  In 
this  affection  the  fundus  of  the  bladder  de- 
presses the  anterior  parietes  of  the  vagina,  and 
forms  a  round  projection,  which  is  frequently 
visible  externally  when  it  passes  the  level  of 
the  orifice  of  the  vulva.  The  disease  is  usually 
developed  during  pregnancy  when  pressure  is 
made  by  the  distended  uterus  upon  the  neigh- 
bouring organs ;  but  cases  have  occurred  at  an 


BLADDER,  ABNORMAL  ANATOMY. 


advanced  period  of  life.  Of  all  the  species  of 
hernia  of  the  bladder,  that  by  the  vagina  occa- 
sions the  most  pressing  symptoms,  and  these 
symptoms  are  principally  owing  to  the  devia- 
tion which  is  produced  in  the  canal  of  the 
urethra,  which  is  drawn  downwards  and  for- 
ward by  the  fundus  of  the  organ,  so  as  to 
prevent  the  passage  of  the  urine  along  it.  In 
this  way  a  complete  retention  of  urine  is  pro- 
duced, together  with  tension,  pain  and  aug- 
mentation of  volume  in  the  abdomen,  agitation, 
sleeplessness,  sympathetic  irritation  of  the 
heart  and  the  brain. 

Considerable  doubt  has  usually  been  ex- 
pressed, whether  hernia  of  the  bladder  is  sus- 
ceptible of  true  strangulation ;  whether  the 
sensibility  of  this  organ  is  of  the  same  na- 
ture as  that  of  the  intestines,  and  whether  its 
constriction  might  give  rise  to  similar  sym- 
ptoms. In  the  case  described  by  Plater,* 
strangulation  does,  however,  appear  to  have 
occurred,  but  the  symptoms  which  he  detailed 
were  not  well  marked.  The  symptoms  given 
by  J.  L.  Petit  f  do  not  appear  sufficient  to 
enable  us  to  distinguish  strangulation  where 
the  bladder  is  implicated  from  that  in  which 
the  intestine  suffers.  Hiccup,  says  Petit,  pre- 
cedes vomiting  in  hernia  of  the  bladder,  while 
in  intestinal  hernia  the  latter  precedes  the 
former  symptom.  If  strangulation  should 
occur,  the  method  of  relief  proposed  by  Du- 
rand,  viz.  to  empty  the  tumour  by  puncture 
with  a  trocar,  appears  rational. 

Inftammatwn. — Inflammation  of  the  blad- 
der may  be  produced  by  a  variety  of  causes  • 
among  them  we  may  mention  external  violence, 
incised  wounds  of  the  organ,  contusions  on 
the  hypogastric  or  perineal  region,  concus- 
sions of  various  kinds,  the  bladder  being  dis- 
tended, the  compression  consequent  upon 
pregnancy,  upon  a  laborious  accouchement, 
upon  the  use  of  the  forceps,  upon  the  pre- 
sence of  a  pessary  or  a  hernial  displacement ; 
the  presence  within  the  organ  of  foreign  bodies, 
whether  introduced  from  without,  generated 
within,  or  derived  from  the  kidneys,  distention 
consequent  upon  retention,  and  the  use  of 
cantharides  and  certain  other  diuretic  me- 
dicines. It  may  also  be  communicated  to  the 
bladder  by  neighbouring  organs,  such  as  the 
kidneys,  the  urethra,  the  prostate,  the  uterus, 
and  the  rectum.  It  may  be  developed  during 
the  progress  of  acute  gastro-enteritis,  may 
succeed  to  certain  articular  inflammations,  to 
certain  cutaneous  affections,  and  to  the  sup- 
pression of  a  hemorrhoidal  or  menstrual 
flux. 

The  affection  is  more  common  in  men  than 
in  women,  and  at  the  approach  of  age  than  at 
any  other  period  of  life.  Boisseau  describes 
the  disease  in  a  male  child  of  two  years  old  ; 
Lesaive  in  a  female  child  of  two  years  and  a 
half.  Acute  inflammation  commonly  affects 
at  the  same  time  more  than  one  of  the  vesical 
tunics ;  there  are,  however,  on  record  two  cases 
in  which  acute  inflammation  was  limited  to 


*  Pott's  Surgical  Works,  vol.  i.  case  26'. 
t  Pott,  loc.  cit. 


*  Obs.  lib.  iii.  p.  830. 

t  Traite  Acs  Mai.  Chir.  tome  ii.  p.  368. 


BLADDER,  ABNORMAL  ANATOMY. 


397 


the  peritoneal  tunic  of  the  organ.*  Dr.  Bail- 
lie  suggests,  as  a  reason  for  such  limitation  to 
this  particular  tunic,  the  quantity  of  cellular 
tissue  interposed  between  the  serous  and  mus- 
cular  tunic,  and  the  laxity  of  their  connection 
the  one  with  the  other.  Chronic  inflammation 
is  frequently  confined  solely  to  the  mucous 
tunic  of  the  organ. 

Acute  cystitis  may  terminate  by  complete 
resolution  ;  it  may  cause  a  secretion  of  pus, 
which  is  either  diffused  in  points  over  the 
greater  part  or  even  the  whole  of  the  surface 
of  the  organ,  or  circumscribed  under  the  form 
of  abscess  ;  may  produce  ulceration,  may  ter- 
minate in  gangrene,  or  it  may  assume  a  chronic 
form. 

If  death  supervene  during  the  intensity  of 
acute  inflammation,  we  find  the  mucous  mem- 
brane strongly  injected,  patches  being  pre- 
sented of  a  brownish  colour,  commonly  in  the 
vicinity  of  the  neck  and  funclus  of  the  organ  ; 
nor  dues  it  appear  that  the  occurrence  of  such 
patches  in  these  situations  can  be  attributed  to 
the  irritation  occasioned  by  the  prolonged  con- 
tact of  acrid  urine.  At  other  times  the  mucous 
membrane  is  thickened,  and  the  veins  much 
dilated  ;  pus  is  disseminated  over  the  surface, 
or  collected  into  foci ;  patches  of  false  mem- 
brane are  extended  over  portions  of  the  organ 
or  floating  in  the  contained  fluid,  and  gan- 
grenous points  are  presented;  these  points  may 
only  affect  the  mucous  tunic,  or  they  may 
aftect  the  entire  thickness;  it  is  sometimes 
studded  with  small  ulcerations,  which  are  more 
or  less  concealed  by  folds  of  the  membrane, 
and  not  unfrequently  it  is  softened.  Usually 
the  organ  is  very  much  contracted,  so  much  so 
as  to  present  only  a  very  small  cavity.  This 
effect  is  induced  by  the  contraction  of  the 
muscular  fibres  which  is  excited  by  the  exten- 
sion of  the  irritation  from  the  mucous  mem- 
brane. 

\\  hen  the  disease  terminates  by  resolution, 
ordinarily,  in  a  short  time,  all  trace  of  the 
existence  of  the  affection  disappears.  In  cer- 
tain cases,  however,  where  it  has  existed  long, 
the  parietes  of  the  bladder  have  been  found 
slightly  thickened;  one  or  more  branches  of 
veins  have  become  varicose  and  consequently 
more  apparent.  If  the  disease  have  had  a  still 
longer  existence,  we  may  find  the  mucous 
membrane  thickened ;  but  this  effect  is  more 
frequently  manifested  in  the  muscular  tunic. 

Vv  hen  a  purulent  secretion  is  produced,  pus 
is  found  diffused  through  the  substance  of  the 
parietes,  more  particularly,  however,  in  the 
cellular  and  muscular  layers,  and  an  appear- 
ance of  hypertrophy  is  here  produced  ;  or  it  is 
poured  out  upon  the  surface  of  the  mucous 
tunic.  Occasionally,  but  unfrequently, abscesses 
are  formed  between  the  tunics,  but  these  are 
commonly  a  consequence  of  wounds  or  con- 
tusions of  this  organ,  or  of  the  operation  for 
stone.  In  such  cases  the  abscess  may  open 
itself  on  the  external  surface  of  the  bladder, 
or  upon  the  interior.  Sometimes  it  is  pre- 


sented upon  the  sides  of  the  rectum,  but 
according  to  Chopart  it  is  usually  in  the 
neighbourhood  of  the  neck  of  the  organ  that 
suppuration  commences.  When  an  abscess 
opens  upon  the  internal  surface  of  the  bladder, 
the  pus  passes  out,  mixed  with  the  urine  ;  in 
such  cases  we  discover  after  death  more  or  less 
extensive  and  profound  fistulous  openings, 
which  are  sometimes  surrounded  by  varicose 
veins,  sometimes  covered  by  dark  grumous 
blood,  extravasated  from  the  small  vessels 
which  ramify  on  them  :  they  all  exhale  a 
fetid  odour. 

Ulceration  of  the  bladder  as  a  consequence 
of  acute  inflammation  is  unfrequent ;  indeed, 
of  this  affection  there  are  only  a  very  small 
number  of  cases  on  record.  When  it  occurs, 
it  is  commonly  caused  by  the  opening  of  a 
purulent  collection  upon  the  mucous  surface 
of  the  organ.  A  case,  detailed  by  Marc-clial 
in  the  28th  vol.  of  the  Recueil  Feriodique  des 
Travaux  de  la  Societe  de  Medecine  de  Paris, 
is  the  best  marked  case  of  the  affection  with 
which  we  are  acquainted.  It  was  that  of  a 
hussar,  in  whom  the  affection  appeared  to  be 
brought  about  by  a  violent  attack  of  gonor- 
rhoea :  the  patient  died  on  the  fifth  day.  Upon 
an  examination  of  the  organ  after  death,  it  was 
found  rather  contracted;  though  not  filled 
with  urine,  its  parietes  sustained  themselves  ; 
it  contained  eight  ounces  of  a  greyish  thick 
matter :  the  mucous  membrane  was  extremely 
thick,  and  covered  by  a  glutinous  stratum. 
It  presented,  however,  many  ulcerations  of 
varied  extent ;  the  parietes  of  the  organ  were 
six  lines  in  thickness. 

Occasionally  it  happens  that  inflammation 
of  the  mucous  membrane  of  the  bladder  pro- 
ceeds to  gangrene,  which  is  characterised  by  a 
change  in  the  volume  of  the  hypogastric  tu- 
mour, supposing  the  organ  to  be  distended, 
the  cessation  of  pain,  the  sudden  prostration 
of  the  vital  powers,  the  complete  suppression 
of  the  flow  of  urine,  the  excessive  distention 
of  the  bladder  and  the  ureters,  and  sometimes 
by  the  escape  of  urine  by  the  umbilicus;* 
more  frequently,  however,  by  the  rupture  of 
the  organ  and  the  extravasation  of  its  contents 
into  the  abdominal  or  pelvic  cavity.  In  cases 
which  are  a  consequence  of  retention,  the  gan- 
grenous points  may  be  presented  either  at  the 
fundus  or  at  the  summit  of  the  organ  ;f  but 
most  commonly  the  affection  is  a  consequence 
of  the  irritation  or  pressure  made  upon  the 
bladder  by  a  foreign  body,  and  in  these  the 
point  implicated  is  that  upon  which  the  body 
has  directly  exercised  its  influence.  When 
we  examine  the  mucous  surface  of  an  organ 
so  affected,  we  discover  that  the  disease  exists 
under  two  distinct  forms,  the  diffuse  and  the 
circumscribed  ;  but  the  latter  of  the  two  forms 
is  not  often  witnessed  except  as  a  consequence 
of  local  violence.  Dr.  Carswell,  however,  bears 
testimony  to  its  occasional  existence  ;  he  states 
that  the  congestion  is  extreme,  and  often  ac- 
companied by  hemorrhage,  which  gives  to  the 


*  See  Baillie,  Wardrop's  edition,  vol.  ii.  p.  259, 
and  Nauche,  Maladies  des  Voies  Urinaires,  p.  27. 


*  Walther,  loc.  cit. 

f  See  Hunter,  Hey,  and  others. 


398 


BLADDER,  ABNORMAL  ANATOMY. 


membrane  a  uniform  deep  red  colour.  More- 
over, dark  brown  or  black  patches  are  found 
to  occupy  portions  of  various  extent  of  the 
mucous  membrane,  which,  as  well  as  the 
submucous  tissue,  is  easily  torn,  and  other 
portions  of  this  membrane  are  seen  partially 
detached,  and  converted  into  a  soft  spongy 
substance  having  a  strong  gangrenous  odour. 
In  the  circumscribed  form  of  gangrene,  we 
sometimes  see  a  number  of  black  eschars, 
which  are  soft  and  nearly  putrid  :  sometimes 
greyish  pulpy  points  are  presented,  which 
appear  to  implicate  only  the  mucous  tunic, 
but  in  the  greater  number  of  cases  we  see  the 
different  stages  of  their  progress ;  they  are  at 
first  whitish,  they  then  become  yellowish,  grey, 
slate  colour  or  brown,  and  blackish  ;  but  these 
changes  are  much  more  marked  when  the  organ 
has  been  subjected  for  a  short  time  to  the 
action  of  the  atmosphere.  Where  the  whole 
of  the  parietes  are  involved,  the  eschar  is 
characterised  by  a  greyish  slaty  tint.  These 
eschars  are  frequently  confounded  with  the 
violet  or  brown  portions  or  patches  by  which 
they  are  surrounded ;  these  latter  are  simply 
extreme  congestion,  bordering,  it  is  true,  upon 
gangrene,  but  susceptible  of  being  restored  to 
a  healthy  state,  whilst  the  death  of  the  other 
points  is  inevitable. 

When  acute  inflammation  affects  the  mus- 
cular tunic  of  the  bladder,  the  organ  usually 
becomes  strongly  contracted,  and  the  parietes 
present  an  appearance  of  considerable  thicken- 
ing ;  at  the  same  time  pus  is  commonly  in- 
filtrated through  the  tissue,  or  it  is  circum- 
scribed into  the  form  of  abscess ;  the  tunic  is 
then  of  a  dark  red  colour  and  strongly  in- 
jected. In  a  case  which  was  seen  by  Gendrin, 
where  the  patient  refused  to  submit  to  the 
operation  for  stone,  the  internal  tunic  was 
ulcerated  and  of  a  red-brown  colour;  the  mus- 
cular tunic  was  more  than  half  an  inch  in 
thickness,  and  contained  two  abscesses,  each 
of  the  size  of  a  small  nut.  Velpeau  saw  in  a 
patient  who  had  died  of  a  diarrhoea,  the  blad- 
der reduced  to  the  size  of  a  small  fist ;  it  was 
hard  and  elastic ;  its  parietes  were  more  than 
an  inch  thick.  In  the  cases  described  by 
Martin  Ripaux,  Molat,  Maret,  and  Berard,* 
the  mucous  membrane  was  not  in  any  way 
implicated,  the  hypertrophy  being  entirely 
limited  to  the  muscular  tunic.  In  these  cases 
the  bladder  was  reduced  to  very  small  dimen- 
sions, and  the  mucous  coat  made  many  pro- 
jections into  the  cavity;  the  summit  of  these 
projections  was  red  and  vascular.  It  is  not 
unlikely  but  that  it  may  be  owing  to  the  excess 
of  extent  of  the  mucous  over  the  contracted 
muscular  tissue  in  such  cases,  that  the  former 
so  easily  becomes  engaged  in  the  formation  of 
appendices.  The  muscular  tunic  may  be 
much  increased  in  thickness  in  the  absence  of 
acute  or  even  chronic  inflammation  of  the 
organ  ;  any  irritation  by  which  a  frequent  con- 
traction of  the  organ  may  be  excited  will  most 
probably  produce  a  great  increase  of  thickness 
of  this  tunic.  Among  these  causes  we  may 


range  the  existence  of  fistula  or  calculi  in  the 
organ.  Sometimes  the  thickening  is  limited 
to  the  mucous  tunic.  M.  Portal,  in  examining 
the  bladder  of  an  old  man,  the  parietes  of  the 
organ  being  eight  or  nine  lines  in  thickness, 
found  the  internal  tunic  like  cartilage,  and 
that  this  was  the  only  tunic  which  had  acquired 
an  increase  of  substance ;  the  peritoneal  tunic 
was  in  its  natural  state,  the  muscular  scarcely 
apparent.  Chopart  made  a  similar  remark 
with  regard  to  the  bladder  of  an  adult.  Mor- 
gagni  mentions  a  like  case.* 

Instead  of  either  of  the  modifications  which 
have  been  described,  acute  cystitis  may  dege- 
nerate into  a  chronic  form  of  the  disease. 
This  form  of  the  affection  does  not  commonly 
succeed  to  a  single  and  simple  attack  of  the 
acute  affection ;  almost  always  there  will  have 
been  sundry  recurrences  of  the  acute  form 
before  this  degeneration  takes  place.  Most 
frequently  chronic  cystitis  occurs  without  hav- 
ing the  acute  disease  as  a  precursor,  and  it  is 
upon  chronic  inflammation  that  extensive  dis- 
organisations of  the  various  tissues  of  the  eco- 
nomy are  mainly  dependent ;  and  the  altera- 
tions of  texture  in  the  parietes  of  the  bladder 
are,  therefore,  most  commonly  produced  by  its 
agency. 

In  such  cases  we  may  see  the  mucous  mem- 
brane of  an  uniformly  dark  violet  colour,  thick- 
ened and  unyielding,  the  organ  so  contracted 
as  to  present  only  a  very  small  undilatable 
cavity,  incapable  of  containing  more  than  a 
few  drams  of  fluid.  Fungous  excrescences 
are  sometimes  developed  upon  its  internal 
surface,  especially  in  the  vicinity  of  the  neck. 
In  some  cases  ulcerations  will  be  found  to 
have  destroyed  the  muscular  tunic  and  pene- 
trated to  the  peritoneum;  in  others,  the 
mucous  follicles  present  a  most  exaggerated 
development,  communicating  to  the  membrane 
a  considerable  increase  of  thickness,  but  with- 
out change  of  colour.  In  other  cases,  the 
muscular  tunic  having  acted  with  increased 
energy,  its  fibres  have  become  more  volumi- 
nous and  project  into  the  interior  of  the 
organ  in  the  form  of  columns,  between  which 
the  mucous  membrane  sometimes  forms  what 
is  termed  '  hernia.'  But  the  more  ordinary 
consequence  of  chronic  inflammation  of  this 
organ  consists  in  the  thickening  and  more  or 
less  uniform  induration  of  the  vesical  pa- 
rietes. The  tissue  of  the  bladder  is  then  con- 
verted into  a  homogeneous,  lardaceous  sub- 
stance, similar  in  appearance  to  that  of  the  un- 
impregnated  uterus;  the  vessels  which  surround 
the  organ  are  dilated,  varicose,  and  form  on 
the  external  surface  considerable  plexuses, 
which  attest  the  long  existence  of  its  excitation, 
and  the  continuance  of  the  afHux  of  blood  of 
which  it  has  been  the  seat. 

Ulceration  as  a  consequence  of  chronic  in- 
flammation of  the  mucous  membrane  of  this 
organ  is  unfrequent,  but  as  an  effect  of  the 
presence  of  a  calculus  is  less  so.  Of  the  first 
species  a  description,  with  a  fine  plate,  is  given 
by  Baillie,  of  a  case  in  which  the  mucous 


Vide  Transact,  de  la  Soci6te  Anatomique. 


*  Ep.  41,  art.  6. 


BLADDER,  ABNORMAL  ANATOMY. 


309 


membane  covering  the  posterior  and  superior 
surface  of  the  bladder  was  destroyed ;  a  simi- 
lar case  is  given  also,  with  a  plate,  by  Walter ; 
another  is  described  by  Pare.*  A  case  is 
described  by  Jalon,f  in  which  the  whole  of 
the  muscular  tunic  was  as  well  displayed  as  if  it 
had  been  prepared  by  dissection.  There  are 
several  well-marked  cases  on  record  in  which 
this  species  of  ulceration,  consequent  upon 
chronic  inflammation,  had  extended  to  the 
whole  of  the  tunics  and  caused  an  extrava- 
sation of  urine.  These  ulcerations  are  some- 
times very  numerous,  almost  like  erosions,  and 
they  are  often  concealed  between  the  folds 
of  the  relaxed  mucous  membrane,  so  that  they 
are  not  discovered  until  the  membrane  is 
stretched  out.  Under  the  influence  of  either 
acute  or  chronic  inflammation,  pseudo-mem- 
branes are  now  and  then  generated  upon  the 
surface  of  the  mucous  tunic  of  the  organ, 
usually  during  the  suppurating  period  of  the 
affection.  These  membranes  are  either  ad- 
herent or  free,  and  they  are  sometimes  ex- 
pelled through  the  urethra :  this  circumstance 
has  induced  a  belief  in  an  often  repeated  error, 
that  the  mucous  tunic  of  the  bladder  may  be 
entirely  detached  and  expelled  witli  the  urine; 
among  those  who  have  perpetuated  this  error 
are  Ruysch  and  Morgagni.J 

Under  the  influence  of  chronic,  and  much 
more  rarely  of  subacute  inflammation,  the 
mucous  membrane  of  the  bladder  furnishes  in 
large  quantity  a  species  of  muco-purulent 
fluid.  This  affection  was  termed  by  Lieu- 
taud  §  catarrh  of  the  bladder.  When  the 
affection  presents  the  subacute  form,  it  is  fre- 
quently extended  to  the  other  tunics  of  the 
organ ;  and  if  we  examine  it  after  death,  we 
shall  find  similar  appearances  to  those  which 
have  been  described  in  speaking  of  acute  in- 
flammation. When  the  disease  is  chronic,  it 
often  lasts  for  years,  and  we  then  discover 
little  change  of  colour  in  the  membrane,  but 
we  find  it  often  prodigiously  thickened,  the 
vessels  varicose,  and  the  cavity  much  con- 
tracted. 

Idiopathic  softening. — During  the  progress 
of  some  acute  and  many  chronic  diseases, 
the  mucous  membranes  of  the  body  not  un- 
frequently  become  softened,  in  the  absence 
of  inflammatory  action  in  their  tissues  :  in  the 
bladder,  however,  this  state  has  been  only  very 
rarely  witnessed.  This  fact  is  important,  espe- 
cially when  we  reflect  upon  the  functions  of 
the  organ  and  the  great  variations  to  which  the 
liquid  of  which  it  is  the  reservoir  is  exposed. 
M.  Louis,||  in  a  very  careful  examination  of 
five  hundred  bodies,  found  this  idiopathic 
softening  in  only  two  cases.  In  these  the 
mucous  membrane  in  a  great  portion  of  the 

*  Lib.  xvii.  ch.  59. 

t  Eph.  Nat.  Cur.  D.  11.  an  11.  obs.  129. 

$  A  case  of  the  kind  is  detailed  by  M.  Destrees 
in  the  Journal  General  de  Medeciue,  tome  Ixviii. 
p.  206. 

$  Med.  Prat.  torn.  i. 

f|  Repertoire  General,  tome  iv.  part  i.  Faits 
relatifs  aux  lesions  de  la  membrane  muqucuse  de 
la  vessie. 


fundus  of  tho  organ  was  reduced  into  a 
"  mucilage"  possessing  a  consistence  little  if 
at  all  superior  to  that  of  mucous  pseudo-mem- 
branes. The  membrane  thus  altered  was  pale, 
even  at  the  limits  of  the  softening ;  there  was 
no  injection  or  vascular  congestion  at  any  point 
of  the  bladder,  nor  in  any  of  the  vessels  which 
existed  on  the  exterior  of  the  organ  ;  neither 
was  there  at  the  interior  any  erosion  or  other 
product  of  inflammation.  It  is  probable  that 
it  is  in  such  cases  that  even  a  careful  intro- 
duction of  the  sound  has  occasioned  a  per- 
foration of  the  bladder;  it  may  be  as  well  to 
mention  that  no  true  friability  of  the  mucous 
membrane,  so  commonly  found  in  inflam- 
mation, existed  in  these  two  cases ;  the  tunic 
was  soft,  as  if  formed  of  a  viscid  jelly,  but  it 
did  not  present  either  the  redness,  the  infil- 
tration or  the  induration  by  which  inflam- 
mation is  characterised.  So  general  is  the 
opinion  that  softening  is  uniformly  a  conse- 
quence of  inflammation,  that  in  taking  an 
opposite  opinion  it  appears  to  be  incum- 
bent upon  us  to  state  our  reasons  for  doing 
so.  Although  the  differences  which  may  be 
remarked  between  softening  of  this  tissue 
and  its  inflammatory  condition  appear  to  be 
very  great,  yet  able  observers  have  still  be- 
lieved themselves  justified  in  regarding  all 
softening  as  the  result  of  inflammation.  It  is 
so  important  to  have  correct  ideas  on  this 
point,  that  we  ought  here  to  refute  the  reason- 
ing by  which  that  opinion  is  supported.  It  is 
stated  that  softening  of  mucous  tunics  is,  in 
the  greater  number  of  cases,  united  to  evi- 
dently inflammatory  alterations;  such  as  a 
more  or  less  vivid  redness  of  the  softened 
parts,  together  with  an  injection  and  tume- 
faction. This  assertion  is  gratuitous;  for  in 
all  cases  where  the  condition  has  been  well 
observed,  softening  in  the  first  degree  has 
scarcely  ever  been  united  to  unequivocal  in- 
flammatory alterations.  In  the  second  degree 
of  softening,  the  existence  of  inflammation  is 
frequently  demonstrable. 

It  is  especially  by  studying  the  anatomical 
characters  of  the  early  stage  of  softening 
that  we  shall  be  enabled  to  establish  the 
non-existence  of  inflammation ;  we  may  go 
farther,  and  say  that  the  characteristics  of  sof- 
tening are  directly  opposed  to  those  of  in- 
flammation. In  the  latter  we  find  injection 
and  vascular  congestion ;  in  the  former  the 
capillaries  have  disappeared; — in  inflammation, 
thickening,  and  at  first  augmentation  of  density 
in  the  membrane,  which  becomes  rugous  to 
the  touch ;  in  softening  we  find  thinning  and 
diminution  in  the  density  of  the  tunic,  with 
loss  of  its  tenacity,  and  it  is  soft  to  the  touch ; 
— in  inflammation  we  observe  specific  inflam- 
matory products  at  the  surface  and  in  the  sub-  • 
stance  of  the  tissue ;  in  softening  a  diminu- 
tion and  absence,  then  a  total  extinction  of  this 
secretion,  which  is  not  only  not  augmented  at 
the  commencement  of  the  disease,  as  in  the 
first  stage  of  inflammation,  but  is  immediately 
diminished. 

Inflamed  tissues  at  a  certain  epoch  do,  it  is 
said,  become  soft  and  friable ;  why  should  it 


400 


BLADDER,  ABNORMAL  ANATOMY. 


not  be  so  in  mucous  or  villous  tissues  ? 
Although  this  reasoning  proves  nothing, — for 
we  cannot  judge  from  analogy  in  a  graphic 
science  like  pathological  anatomy, — yet  it  is 
the  simple  expression  of  the  truth,  because  it 
is  certain  that  mucous  tunics  are  softened  by 
inflammation,  but  this  softening  does  not  re- 
semble in  any  thing  the  idiopathic  softening. 

Rupture. —  Rupture  of  the  bladder  is  a 
more  frequent  occurrence  than  that  of  the 
oesophagus,  the  stomach,  or  the  intestines ;  it 
occurs  sometimes  without  external  violence, 
simply  by  a  distention  of  the  organ,  from  a 

Erolonged  retention  of  urine  ;  most  commonly, 
owever,  it  is  produced  by  a  violent  blow,  or 
the  passage  of  the  wheel  of  a  carriage  over  the 
hypogastnum,  or  the  violent  efforts  to  which 
a  woman  is  subject  during  the  pains  of  labour, 
the  bladder  being  in  a  state  of  plenitude.  In 
the  first  case,  the  rupture  usually  occurs  near 
the  insertion  of  the  ureters  or  the  neck  of  the 
bladder,  because  it  is  at  these  points  that  the 
distended  organ  usually  begins  to  thin  and  tear. 
In  the  second  case  it  is  usually  at  the  inferior 
fundus  of  the  organ  that  the  rupture  is  found. 

We  have  already  pointed  out  the  circum- 
stances under  the  influence  of  which  the  blad- 
der may  be  ruptured,  and  wre  have  stated  that 
the  extravasation  of  urine  by  which  it  is  fol- 
lowed is  commonly  productive  of  fatal  con- 
sequences. 

in  a  certain  but  small  number  of  cases, 
the  patient  is  able  to  resist  the  inflammatory 
symptoms  which  are  developed,  urinary  ab- 
scesses are  formed,  which  may  open  either  in 
the  vicinity  of  the  umbilicus,  at  the  hypo- 
gastrium,  in  the  inguinal  region,  in  the  vagina, 
at  the  perineum,  or  in  the  rectum,  and  a  fistu- 
lous  canal  is  organised. 

Fistula.  —  Fistulous  communications  be- 
tween the  bladder  and  the  vagina  or  in- 
testines are  commonly  the  result  of  purely 
mechanical  causes,  such  as  the  action  of  a 
calculus  which  may  destroy  the  recto-vesical 
septum,  the  action  of  a  foreign  body  introduced 
into  the  anus  and  penetrating  the  bladder, 
the  lateral  ised  or  recto-vesical  operation  for 
stone,  the  operation  of  lithotrity,  or  as  a  con- 
sequence of  the  pressure  produced  by  the 
head  of  the  child  in  parturition.  Vesico-in- 
testinal  fistulse  sometimes  establish  a  com- 
munication between  the  bladder  and  the  ileum 
pr  colon,*  and  then  the  summit  of  the  bladder 
is  usually  the  seat  of  injury.  When  the  com- 
munication is  established  between  the  bladder 
and  the  rectum,  the  posterior  surface  of  the 
bladder  is  commonly  implicated ;  the  neck  of 
the  bladder  may,  however,  be  similarly  affected, 
and  then  it  is  commonly  owing  to  the  action 
of  a  calculus  or  other  foreign  body  directed 
upon  this  portion  of  the  vesical  parietes.  At 
other  times  the  lesion  succeeds  to  chronic  in- 
flammation, or  to  a  cancerous  ulcer  which  has 
extended  from  the  rectum  to  the  bladder ;  and 
then  the  perforation  almost  always  exists  near 
the  neck  of  the  latter.  The  communication  of 

*  London  Med.  Journal  for  1784,  part  2  ;  Edin- 
burgh Medical  Commentaries,  vol.  ii.  part  2. 


the  intestine  with  the  bladder  is  sometimes 
established  without  abscess,  without  external 
inflammation.  Sometimes  the  urine  does  not 
escape  by  the  rectum,  wh.le  fsecal  matter  and 
flatus  pass  from  the  rectum  into  the  bladder. 

Ordinarily,  however,  the  urine  passes  into 
the  rectum  and  often  causes  diarrhoea;  the 
bladder,  distended  by  intestinal  gas,  forms  a 
sonorous  and  painful  tumour  at  the  hypo- 
gastrium. 

Vesico-vaginal  fistulas  are  sometimes  though 
rarely  occasioned  by  the  action  of  a  foreign 
body  introduced  into  the  vagina;  sometimes 
they  are  the  result  of  the  progress  of  a  uterine 
cancer ;  but  in  general  the  cause  by  which 
they  are  produced  is  a  laborious  accouchement, 
during  which  the  head  of  the  infant  has  re- 
mained long  in  the  passage,  and  has  by  its 
pressure  determined  gangrene  of  the  vesico- 
vaginal  septum.  The  accident  may  be  pro- 
duced by  the  imprudent  use  of  instruments ; 
but  this  is  a  rare  occurrence,  perhaps  for  the 
reason  that  instruments  are  comparatively  un- 
frequently  employed.  In  a  few  days  the 
eschars  which  are  the  result  of  that  gangrene 
are  thrown  off,  and  the  consequent  loss  of  sub- 
stance may  then  be  demonstrated.  We  find 
that  these  fistulas  have  not  always  the  same 
form,  the  same  direction,  nor  the  same  extent. 
In  some  cases  they  are  longitudinal,  at  other 
times  transverse ;  in  others  their  form  is  irre- 
gular. The  extent  of  the  loss  of  substance  is 
also  very  variable:  sometimes  the  fundus  of 
the  bladder  is  extensively  destroyed,  so  much 
so  as  to  allow  of  the  opposite  parietes  of  the 
organ  being  implicated  in  the  opening,  and 
forming  a  true  vesico-vaginal  hernia.  When  the 
disease  is  a  vesico-umbilical  fistula,  the  com- 
munication is  with  the  summit  of  the  bladder, 
and  is  commonly  caused  by  a  dilatation  of  the 
urachus  or  by  the  prolongation  of  the  mucous 
membrane  of  the  bladder,  which  is  directed 
along  the  cord  produced  by  the  conversion  of 
the  urachus  and  the  vessels  by  which  it  is 
accompanied  into  a  cellular  structure.*  In 
either  case  the  disease  is  almost  invariably  a 
consequence  of  the  existence  of  some  ob- 
stacle to  the  passage  of  urine  along  the 
urethra. 

The  pubic  and  inguinal  fistulae  succeed  to 
an  accidental  opening  of  the  bladder,  which, 
having  formed  a  tumour  in  those  regions, 
has  been  taken  for  an  abscess,  a  hernia,  or  an 
encysted  tumour;  to  wounds,  to  ruptures, 
puncture,  or  incision  of  the  organ ;  to  its  per- 
foration in  consequence  of  a  purulent  focus 
being  in  contact  with  its  parietes,  or  by  a  suppu- 
ration in  these  parietes  themselves.  All  fistulae 
of  the  bladder  have  this  in  common,  that  the 
urine  escapes  from  their  orifice  drop  by  drop, 
almost  continually,  often  without  contraction 
of  the  bladder,  and  without  the  patient  having 
wished  to  urine ;  sometimes  it  escapes  in 
greater  quantity  during  those  motions  of  the 
body  which  excite  the  pressure  of  the  abdo- 
minal muscles.  In  consequence  of  the  habit 
which  the  bladder  has  acquired  of  remaining 

*  See  Van-der-Wiel,  Littre,  Tenon,  and  Roux. 


BLADDER,  ABNORMAL  ANATOMY. 


401 


empty,  it  almost  always  becomes  contracted  ; 
in  all  cases  its  capacity  is  considerably  di- 
minished. 

Htemorrhage  from  the  bladder. — Instead  of 
the  mucus  which  is  furnished  by  the  mucous 
membrane  of  the  bladder  when  in  the  state  of 
health,  it  may  be  the  seat  of  a  sanguineous 
exhalation.  When  a  sanguineous  fluid  is 
excreted  from  the  bladder,  it  does  not  of  neces- 
sity follow  that  it  has  proceeded  from  the 
mucous  membrane  of  that  organ  ;  it  may  be 
brought  by  the  ureters  from  the  kidneys. 
When  the  fluid  is  produced  within  the  vesical 
cavity,  the  mode  of  production  is  not  uniform  : 
it  may  be  a  simple  exhalation  from  the  mu- 
cous membrane,  or  it  may  be  a  consequence 
of  the  destruction  of  the  mucous  membrane 
by  gravel,  by  a  calculus,  or  by  a  foreign  body 
introduced  from  without ;  or  it  may  be  a  con- 
sequence of  the  rupture  of  varicosed  vessels. 
Blood  is,  however,  rarely  exhaled  at  the  in- 
ternal surface  of  the  bladder,  unless  the  mu- 
cous membrane  be  in  a  state  of  structural 
disease :  yet  this  exhalation  is  occasionally 
manifested  as  a  result  of  intemperance,  or  the 
use  of  certain  irritating  diuretic  medicines, 
concussions  of  the  pelvis ;  in  woman  the  sud- 
den suppression  of  the  menstrual  evacuations, 
and  in  man  of  a  hemorrhoidal  discharge. 

It  is  very  difficult,  and  sometimes  even  al- 
most impossible  to  determine  whether  the 
fluid  be  derived  from  the  kidney  or  from  the 
bladder;  and  to  arrive  at  any  thing  like  a  sound 
opinion,  it  is  necessary  to  consider  carefully  all 
the  circumstances  of  the  case.  Much  as  it  has 
been  relied  on,  we  cannot  consider  as  a  sym- 
ptom peculiar  to  vesical  haemorrhage,  the  mix- 
ture of  blood  with  the  urine,  and  the  sensation 
of  burning  and  weight  behind  the  pubis,  at  the 
perineum,  and  at  the  extremity  of  the  penis ; 
for  these  symptoms  occur  in  some  cases  where 
there  is  no  effusion  of  blood,  and  in  others 
where  the  blood  has  arrived  from  the  kidneys. 
It  is  also  very  difficult  to  decide  as  to  what 
is  the  exact  state  of  the  bladder,  even  when 
we  are  convinced  that  the  blood  discharged 
from  the  urethra  is  derived  from  that  organ, 
Chopart  found  the  vesical  mucous  membrane, 
more  particularly  at  the  fundus,  studded  with 
red  points  in  an  old  man  subject  to  haematuria; 
these  points  appeared  to  him  to  be  vascular 
orifices.*  In  other  persons  who  have  suffered 
from  a  similar  affection,  different  kinds  of 
fungus  have  been  discovered  on  this  mem- 
brane. A  man,  aged  seventy-three,  had  haema- 
turia, but  there  was  no  stone  in  the  bladder. 
As  there  was  no  appearance  of  disease  about 
the  kidneys,  it  was  attributed  to  the  rupture  of 
some  varicose  vessels  in  the  neighbourhood 
of  the  neck  of  the  organ.  After  death  the 
bladder  was  found  of  great  size,  and  within  the 
trigone  was  a  fungous  rounded  ulceration,  six 
lines  in  diameter,  surrounded  with  varicose 
veins  and  small  fungous  excrescences.  Ordi- 
narily, however,  gravel  or  calculi  appear  to  be 
the  exciting  causes  of  this  disease. 


*  Loc.  cit.  tome  ii.  p.  52. 


VOL.  I. 


Fungous  tumours. — The  information  which 
we  possess  on  the  subject  of  fungous  tumours 
or  excrescences  of  the  bladder  is  not  sufficiently 
precise  to  enable  us  to  attempt  to  arnmgv 
them  according  to  their  variety  in  structure  or 
development.  The  tumours  which  we  pro- 
pose to  describe  are  those  which  do  not  im- 
plicate the  whole  of  the  parietes  of  the  organ, 
but  project  into  its  cavity  under  the  form  of 
more  or  less  perfectly  pediculated  excrescences. 
We  are,  therefore,  under  the  necessity  of  con- 
sidering simultaneously  all  those  tumours, 
however  variable  in  structure,  which  come 
under  the  definition  which  we  have  given. 
Many  eminent  pathologists  have  expressed  an 
opinion  that  these  tumours  are  always  directly 
connected  with  the  prostate  ;  but  their  occa- 
sional existence  in  the  female  sufficiently 
proves  that  this  opinion  is  incorrect.  In  J  750 
Mr.  Warner  removed  from  the  bladder  of  a 
woman  a  fungous  tumour  of  the  shape  and 
size  of  a  turkey's  egg.  Walter*  details  the 
case  of  a  young  woman  in  whose  bladder  he 
discovered  what  he  calls  a  polypus,  which  ex- 
tended itself  nearly  to  the  external  orifice  of  the 
urethra.  It  is  true  that  these  morbid  products  are 
more  commonly  seen  at  the  fundus  of  the  blad- 
der than  at  any  other  point  of  its  surface,  and  it 
is  equally  true  that  a  large  number  of  those 
affections  which  are  described  as  fungous  tu- 
mours of  the  bladder,  were  really  morbid 
products  arising  from  the  prostate,  which  will 
be  described  in  the  article  on  the  PROSTATE 
GLAND. 

The  circumstances  necessary  for  the  develop- 
ment of  these  tumours  are  unknown,but  it  would 
appear  that  the  larger  number  occur  under  the 
influence  of  irritation  produced  by  calculus. 
Ordinarily  only  one  of  these  tumours  is  found, 
and  then  occasionally  it  attains  a  considerable 
volume.  Fabricius  Hildanusf  describes  one 
of  the  size  of  a  hen's  egg,  and  weighing  two 
ounces.  Zacutus  LusitanusJ  found  one  of 
these  polypi  of  the  size  of  a  goose's  egg,  and 
so  hard  that  he  could  not  cut  it  with  scissars. 
There  are,  however,  many  examples  in  which 
a  greater  number  existed,  but  in  these  cases 
the  tumours  are  usually  small.  Chopart  §  de- 
scribes a  case  which  he  examined  at  the  Hotel 
Dieu,  in  which  there  were  found  three  tumours, 
the  largest  being  nearly  as  large  as  a  cherry. 
Ludwig  describes  a  case  in  which  he  found 
two  of  small  size  in  the  bladder  of  a  man  of 
sixty-three.  Desault  once  saw  the  whole  of 
the  cavity  of  the  bladder  studded  with  small 
"  fungous  tubercles."  Lobstcin  ||  has  seen 
three,  and  Bartholin^T  two.  This  affection  is 
rarely  seen  before  adult  age.  Morgagni**  has 
never  seen  them  in  infants  or  in  young  persons. 


*  Einige  Krankheiten  d.  Nicren  und  Harnblasc, 
4to.     Berlin,  1800,  tab.  iii. 
t  Cent.  ii.  obs.  65. 
j   Prax.  Mod.  Adcr.  lib.  ii.  obs.  71. 
Loc.  cit.    tome  ii.  p.  77. 
Piss,  de  Hysuria. 
Anat.  cent.  ii.  Hist.  52.  p.  243. 
De  Sed.  cp.  Ixvi.  ait.  12. 

2    D 


402 


.  BLADDER,  ABNORMAL  ANATOMY. 


Deschamps,  in  1791,  whilst  removing  a  cal- 
culus from  the  bladder  of  a  boy  of  twelve 
years,  discovered  on  the  anterior  and  lateral 
parietes  of  this  organ,  a  small  fungous  tumour 
of  the  size  of  a  cherry,  which  projected  to  the 
distance  of  half  an  inch  from  the  surface. 
Baillie,  in  his  Morbid  Anatomy,  has  given  a 
plate  of  a  polypus  of  the  bladder  which  he 
found  in  a  child,  and  which  not  only  occupied 
the  whole  of  the  cavity  of  the  organ,  but  sent 
prolongations  into  the  urethra. 

The  structure  of  these  tumours  is  very  va- 
rious ;  the  greater  number  appear  to  possess  a 
fibrous  structure,  others  present  a  white  homo- 
geneous, lardaceous  texture  at  their  base,  whilst 
their  free  surface  may  be  red,  vascular,  or  even 
carcinomatous ;  sometimes  they  are  hard  and 
almost  cartilaginous  in  their  whole  thickness ; 
at  others  they  present  calcareous  concretions. 

Around  the  points  from  which  these  tumours 
arise  the  bladder  is  ordinarily  thickened  and 
indurated :  this  is,  we  apprehend,  a  consequence 
of  the  continued  irritation  which  has  attended 
their  development. 

Vurices.  —  The  arteries  and  veins  of  the 
bladder  present  numerous  ramifications  in 
the  cellular  stratum,  which  separates  the 
muscular  from  the  mucous  tunic  of  this 
organ ;  and  in  the  neighbourhood  of  its  neck 
they  form  an  immediately  apparent  plexus. 
This  vascular  structure  in  inflammation  be- 
comes so  marked  that  the  mucous  membrane 
appears  to  be  entirely  formed  of  these  vessels. 
Though  it  might  be  expected  that  during  the 
existence  of  inflammation  these  vessels  would 
become  more  dilated  and  manifest,  yet  it 
cannot  be  regarded  as  a  true  varicose  condi- 
tion, there  being  neither  partial  dilatations 
nor  projecting  indurations  like  those  which 
characterize  varices  situated  in  other  parts  of 
the  body.  Bonnet  describes  the  case  of  a 
man,  who  during  life  had  suffered  from  the 
ordinary  symptoms  of  stone,  but  in  whose 
bladder  no  stone  was  discovered  after  death. 
The  veins  around  the  neck  of  the  bladder 
were  varicose  and  very  much  distended 
with  blood.*  Morgagni  discovered  in  the 
body  of  a  man  aged  sixty,  in  which  the 
tunics  of  the  bladder  were  very  thick,  large 
vessels  creeping  along  its  internal  surface 
around  its  neck.  They  were  so  distended  with 
blood,  that  at  first  he  almost  believed  they 
were  haemorrhoids  rather  than  parallel  vessels.f 
A  similar  case  is  described  by  Chopart,  in  a 
calculous  patient.  There  cannot,  therefore, 
be  any  doubt  that  such  a  disease  may  exist. 
It  appears  to  occur  principally  when  the 
parietes  of  the  bladder  are  thickened,  when  it 
contains  calculi  or  fungi,  or  when  its  neck  or 
the  prostate  are  tumefied.  It  is  not  unfrequent 
in  old  men  and  in  inhabitants  of  warm 
countries.  The  disease  has  much  analogy 
with  haemorrhoids,  and  appears  to  increase 
under  similar  sources  of  irritation.  It  may 
contract  the  neck  of  the  bladder  and  so  cause 


*  Sepul.  lib.  iii.  sed.  25,  p.  263. 
t  De  Sed.  ep.  63   art.  13. 


retention.  These  veins  may  become  inflamed 
and  produce  divers  alterations  in  the  mucous 
tissue.  This  membrane  may  be  thinned,  take 
a  fungous  appearance,  give  rise  to  haemor- 
rhage, in  fact  assume  somewhat  of  an  erectile 
character. 

Scirrhm  and  Cancer. — Cancer  primitively 
affecting  the  membranes  of  the  bladder  is  an 
extremely  rare  disease.  Chopart  relates  only 
one  example  of  the  kind.*  Desault  describes 
another;f  Lallemand  another.]:  Soemmering 
appears  to  doubt  whether  the  disease  ever 
exists.§  In  each  case  to  which  I  have  alluded 
the  disease  occurred  in  man,  and  I  know  of 
no  case  on  record  in  which  the  disease  has 
primarily  existed  in  the  bladder  in  woman. 
In  the  whole  of  the  cases  the  disease  was 
characterized  by  lancinating  pains  behind  the 
pubis,  and  by  the  emission  of  particles  of  de- 
composed animal  matter ;  these  were  the  only 
symptoms  which  were  calculated  to  excite 
suspicion  as  to  the  nature  of  the  disease.  In 
every  one  of  them  the  scirrhus  was  situated  in 
the  fundus  of  the  bladder  and  near  its  neck. 
The  whole  of  the  membranes  at  that  point 
were  transformed  into  a  scirrhous  lardaceous 
substance,  varying  in  thickness  from  two  to 
four  inches,  and  in  two  cases  the  tumours  were 
somewhat  funnel-shaped,  the  internal  surface 
of  which  was  unequal,  bristling  with  very 
projecting  vegetations  of  a  cauliflower  cha- 
racter. Most  commonly  the  affection  is  the 
result  of  the  extension  of  a  similar  disease 
from  the  uterus  or  the  rectum,  and  the  symp- 
toms by  which  the  affection  might  be  announced 
are  confounded  with  those  of  the  affection  of 
the  uterus  or  of  the  rectum.  This  affection 
may  exist  with  dilatation  or  contraction  of  the 
cavity  of  the  organ,  with  or  without  ulceration, 
with  or  without  hypertrophy  of  the  muscular 
tunic.  When  derived  from  the  uterus,  the 
affection  is  manifested  at  the  fundus  of  the 
organ,  and  a  communication  is  usually  soon 
brought  about  between  it  and  the  vagina,  and 
as  a  consequence  the  urine  flows  involuntarily 
from  the  vulva.  When  derived  from  the  rec- 
tum, the  fundus  is  commonly  affected  ;  and  in 
either  case  these  productions  are  manifested 
within  the  vesical  cavity  under  the  form  of 
fungous  vegetations. 

Paralysis. — The  bladder  is  not  an  excep- 
tion to  the  rule,  that  "  all  parts  of  the  body 
may  become  unfit  for  the  functions  which  they 
are  destined  to  perform  ;"  it  may  lose  the  fa- 
culty of  contractility,  which  is  indispensable  to 
the  accomplishment  of  excretion.  Under  many 
circumstances  it  may.  contract  with  too  much 
force ;  in  a  still  greater  number  its  contracti- 
lity is  enfeebled  and  ultimately  destroyed. 
Apoplexy,  hemiplegia,  paraplegia,  concussion, 

*  Traite  des  Maladies  des  voies  urinaires,  tome  i. 
p.  466.  Edit,  de  1821. 

t  Traite  des  Maladies  des  voies  urinaires,  3d  edit, 
p.  177. 

\  Obs.  sur  les  maladies  des  organes  genito- 
urinaires,  p.  8. 

§  Traite  des  Mai.  de  la  vessie  et  de  1'uretre,  trad, 
de  H,  Bollard,  1824. 


BLADDER,  ABNORMAL  ANATOMY. 


and  inflammation  of  the  brain  and  its  meningcs, 
extravasations  within  the  cranium,  and  still 
more  concussion  and  inflammation  of  the  spinal 
marrow  and  its  membranes,  and  extravasations 
within  the  spinal  canal,  consequences  of  con- 
tusions of  this  part;  the  excessive  distention  of 
the  bladder  by  the  accumulation  of  urine 
within  its  cavity,  either  in  consequence  of 
neglecting  to  attend  to  the  desire  of  excretion, 
or  because  the  want  has  been  resisted  by  false 
delicacy,  or  because  an  obstacle  exists  at  the 
neck  of  the  bladder  or  in  the  urethra;  inflam- 
mation of  the  mucous  membrane,  especially 
when  it  affects  the  neighbourhood  of  the  neck 
of  the  organ  ;  the  sudden  cessation  of  articular 
pains,  inflammations  of  the  skin  or  of  the 
genital  organs ;  exasperated  gastro-enteritic  af- 
fections which  are  accompanied  by  affections 
of  the  brain  and  the  spinal  marrow  ;  abuse  of 
the  sexual  organs ; — these  are  among  the  cir- 
cumstances under  the  influence  of  which  the 
bladder  loses  partially  or  completely  its  con- 
tractility. 

We  must  not  therefore  regard  all  cases  of 
paralysis  of  the  bladder  as  evidence  of  feeble- 
ness, nor  confound  the  inability  to  contract, 
with  those  mechanical  obstacles  which,  acting 
on  the  bladder  or  the  urethra,  oppose  the  ex- 
cretion of  urine.  We  should  always  endeavour 
to  ascertain  whether  there  be  a  real  paralysis  of 
the  bladder  in  cases  where  the  brain  or  the 
spinal  marrow  is  injured,  and  where  there  is 
detected  abuse  of  the  sexual  organs.  When 
retention  is  primitively  the  effect  of  inattention 
to  the  desire  to  pass  urine,  there  is  only  exces- 
sive distention  of  the  muscular  fibres,  but  that 
distention  is  formidable  in  its  effects ;  for  no 
fact  is  better  established  than  this,  that  when 
we  submit  muscular  fibre  to  excessive  distention 
or  contusion,  it  loses  the  faculty  of  contracting. 
Again,  in  cases  of  inflammation  of  the  bladder, 
there  is  less  of  paralysis  than  a  suspension  of 
contraction  in  the  muscular  tunic,  in  conse- 
quence of  the  proximity  of  the  mucous  tunic, 
which  by  reason  of  its  inflammatory  state  be- 
comes still  more  painful  when  its  tissue  is 
ruffled  by  contraction.  There  may,  however, 
be  atony  or  even  a  real  paralysis  of  the  mus- 
cular tunic  during  the  existence  of  inflammation 
of  the  mucous  tissue. 

It  is  important  to  distinguish  the  case  where 
paralysis  is  simple  from  those  in  which  it  is 
complicated  by  inflammation  of  the  mucous 
membrane  of  the  bladder  or  that  of  any  other 
organ,  and  for  that  purpose  it  is  necessary  to 
analyse  with  care  the  symptoms.  We  must 
also  bear  in  mind  that  from  simple,  complete, 
and  primitive  paralysis  of  the  muscular  tunic 
to  inflammation  of  its  mucous  tunic,  the  inter- 
val is  only  very  short,  in  consequence  of  the 
irritating  impression  which  is  exercised  by  the 
accumulated  urine  which  has  become  much 
deteriorated  in  its  qualities  by  its  prolonged 
retention.  From  the  time  when  paralysis  is 
fairly  established,  the  bladder  is  quite  insensi- 
ble to  the  stimulus  of  the  urine — it  is  merely 
an  inorganic  sac,  which  may  become  enor- 
mously distended.  Haller  found  in  a  drunkard 


403 

the  bladder  so  dilated  that  it  was  capable  of 
containing  twenty  pounds  of  water.*  Fiiinkf 
saw  a  similar  bladder  which  simulated  ascites; 
he  evacuated  from  it  at  onetime  twelve  pounds 
of  urino  without  removing  all  thut  it  contained. 
Willkun  Hunter,  in  his  Anatomy  of  the 
(.•ravid  Uterus,  plate  26,  has  given  a  fine  repre- 
sentation of  a  bladder  which  extended  as  far 
as  the  xiphoid  cartilage  of  the  sternum. 

This  affection  may,  according  to  Baillie,f 
exist  during  two  distinct  states,  one  when  the 
muscular  tunic-  of  the  bladder  has  lost  its 
contractile  power,  the  other  while  that  power 
is  still  retained.  He  adds,  that  after  death 
these  two  cases  cannot  be  distinguished  the 
one  from  the  other,  but  that  by  an  attentive 
examination  of  the  symptoms  the  existence  of 
each  may  be  recognised  during  life.  It  may 
be  complicated  with  inflammation  of  the  organ, 
and  in  this  case  rupture  of  the  bladder  may 
occur, §  to  which  may  be  added  the  case  of 
the  celebrated  Tycho  Brahe.jj  Zuber^f  dis- 
tinguishes this  affection  into  that  of  the  neck 
and  that  of  the  body,  and  this  distinction  is 
important,  for  the  second  being  sometimes 
accompanied  by  a  species  of  spasm  or  want  of 
consent  in  the  neck,  a  retention  of  urine  must 
be  the  result,  whilst  the  former  occasions 
incontinence  of  that  fluid. 

Spasm. — Spasm  of  the  bladder  is  an  affec- 
tion of  frequent  occurrence ;  it  accompanies  the 
various  forms  of  cystitis,  calculus,  and  often  in- 
flammation of  the  urethra.  In  fact  it  may  be  ex- 
cited by  any  kind  of  irritation  of  the  bladder  or 
urethra,  or  by  certain  affections  of  the  kidneys 
and  of  the  rectum.  It  is  not  our  purpose  to  con- 
sider in  this  place  any  other  than  what  may  be 
termed  the  idiopathic  species  of  this  affection. 
Hoffmann  describes  the  case  of  a  man  who 
sank  under  the  numerous  and  violent  attacks 
of  this  disease,  and  in  whom,  after  death, 
except  in  one  particular,  the  bladder  was  found 
perfectly  healthy ;  this  was  in  the  thickening 
and  dilatation  of  its  vessels,  in  which  there 
was  still  much  blood.  Of  course,  although  no 
anatomical  lesion  was  found  in  this  case,  some 
irritation  capable  of  exciting  the  spasm  must 
have  existed. 

BIBLIOGRAPHY.— Rutty,  A  treatise  on  the  urinary 
passages,  £c.  4to.  Lond.  1726.  Zither,  Diss.  de 
vesicae  urinariae  morbis,  4to.  Argent.  1771.  Adams 
on  stone  and  gravel,  diseases  of  the  bladder,  &c. 
8vo.  Lond.  1772.  Lentin,  Krankheiten  der  Harn- 
blase  der  Alien,  in  Ej.  Beytrage  iii.  Bd.  1780. 
Troja,  Mali  della  vesica  oriuaria,  2  vol.  8vo.  Nap. 
1785-88.  Frank,  J.  P.  Oral,  de  vesica  uri-iaria 
ex  vicinia  morbosa  aegrotante,  8vo.  Ti-in.  1786,  in 
Ej.  opusc.  No.  4.  Malacarne,  Osserv.  anat.  e 
pathol.  sugli  ora;ani  uropoetici,  in  Mem.  della  Soc. 
Ital.  vol.  iii.  et  vol.  v.  1780.  Chapart,  Des  ma- 


*  Elementa  Physiologies,  art.  Vesica. 

t   Oratio    de  signis    morborum  ex  corporis  situ, 
partiumque  positione  pateudis,  Ticini,  1788. 

f  Path.  Anat.  chap.  xiii. 

$  See    cases   related    by   Ploucquet,  Bibl.   MeJ. 
Pract. 

||  Petri   Gassendi  Tychonis    Biahei  vita,  Paris, 
1654,  in  4to.  p.  206. 

^1    Diss.  de  Morbis  vesicae. 

2   D  2 


404 


BLOOD. 


ladies  des  voics  urinaires,  8vo.  Paris,  1791.  Mac- 
beath  on  affections  of  the  urinary  organs  among  ne- 
groes, in  Edinb.Mcd.  Comment. "Dec.  2,  vol.x.  1798. 
Desault,  Des  maladies  des  voies  urinaires  (a.  Bichat 
Ed.)  8vo.  Paris,  1799.  Sherwen  on  diseased  and 
contracted  urinary bladder,8vo.  Lond.1799.  Walter, 
Einige  Krankheiten  der  Nieren  und  Harnblase  un- 
tersucht,  4to.  Berl.  1800.  Bell,  Engravings  of 
morbid  parts,  fol.  Lond.  1803.  Schmidt,  Ueber  derj. 
Krank.  der  Harnblase,  &c.  8vo.  Wien.  1806.  Soem- 
mering,  Ueher  lodtlichen  Krankheiten  der  Harn- 
blase, 4to.  Frft.  a  M.  1809.  Nauche,  Des  mal. 
de  la  vessie,  &c.  8vo.  Paris,  1810.  Wadd,  Cases 
of  diseased  bladder,  Lond.  1815.  Howship  on  the 
diseases  of  the  urinary  organs,  8vo.  Lond.  1816. 
Coquin  du  Martel,  Vice  de  conformation  des 
voies  urinaires,  &c.,  in  Bullet,  de  la  Soc.  Med. 
d'Emulat.  Juin  1824.  Lallemand,  Sur  les  malad. 
des  organes  genito-urinaires,  8vo.  Paris,  1824. 
Brodie,  Lectures  on  the  diseases  of  the  urinary 
organs,  &c.  8vo.  Lond.  1834.  *  *  *  *  De- 
tharding,  De  hzemorrhoid.  vesicae,  Rost.  1754 
(Rec.  in  Haller  Disp.  Pathol.  t.  vii.).  Ludwig, 
De  ischuria  ex  tumoribus  vesicae,  4to.  Lips.  176', 
in  Ej.  Advers.  Med.  vol.  ii.  *  *  *  *  Salzmann, 
De  hernia  vesicae  urinariae,  Argent.  1732  ( Rec.  in 
Haller  Disp.  Chir.  t.  iii.)  Camper,  De  vesicae 
herniis,  in  Ej.  Demonst.  Anat.  Pathol.  lib.  ii. 
Sandifort,  De  hernia  vesicae,  in  Ej.  Obs.  Anat. 
Pathol.  lib.  i.  Roose,  De  native  vesicae  urin. 
inversae  prolapsu,  4to.  Getting.  1793.  Baittie, 
Remarkable  deviation  from  the  natural  structure 
in  the  urinary  bladder,  &c.,  Transactions  of  a 
Society  for  the  Improvement  of  Medical  and  Chi- 
rurgical  Knowledge,  vol.  i.  Goeckel,  De  vesica 
spongiosa  extra  abdomen  posita,  Miscel.  Acad.  Nat. 
Curios.  Dec.  2,  A.  5.  Raijfer,  Diss.  sur  la  cysto- 
cele  ou  hernie  de  la  vessie  urinaire,  4to.  Paris, 
1805.  Beugin,  Diss.  sur  la  cystocele,  4to.  Paris. 
1805.  Isenjiamm,  Beschreibung,  &c.  angebornen, 
vorgefallenen,  ungestlilpten  Harnblase,  &c.  8vo. 
Dorpat.  1806.  Fuchs,  Hist.  anat.  prolapsus  nativi 
vesicae  urinariae  inversae,  4to.  Jenae,  1813.  *  *  *  * 
Cases  of  double  bladder,  by  Bordenave,  in  Mem. 
de  Chirurg.  t.  ii. ;  by  Lebenwaldt,  in  Miscell.  Acad. 
Nat.  Curios.  Dec.  2,  A.  8,  1689;  by  Tenon,  in 
Mem.  de  Paris,  A.  1768 :  by  Bussiere,  in  Phil. 
Trans.  1701.*  *  *  *  Cases  of  absence  of  the  bladder, 
by  Preuss,  in  Miscel.  Ac.  Nat.  Cur.  Dec.  2,  An.  7  ; 
by  Rengger,  in  Museum  der  Hcilkunde,  B.  2  ;  by 
Labourdette,  in  Sedillot's  Rec.  Period,  t.  xxxii. 
Cases  of  rupture  of  the  bladder,  by  J.  Johnstons, 
in  Mem.  of  the  Med.  Soc.  of  London,  vol.  iii.  ; 
by  Kundmann,  in  Acta  Acad.  Nat.  Curios,  vol.  vii. ; 
by  Montagu,  in  Med.  Communications,  vol.  ii. ;  by 
Zuinger,  in  Ephem.  Nat.  Curios.  Cent.  7  et  8  ;  by 
Berchelmann,  in  Acta  Hassica,  A.  1771  ;  by  Berner, 
in  Ephem.  Nat.  Curios.  Cent.  9  et  10;  by  Schlich- 
tung,  in  Acta  Ac.  Nat.  Curios,  vol.  vi.  ;  by  Hey, 
in  Med.  Obs.  by  a  Soc.  of  Phys.  vol.  iv.;  by  Lynn, 
in  the  same  work,  vol.  iv.  ;  by  Sedillot,  in  Rec. 
Period,  t.  i. ;  and  by  Cusack,  in  Dub.  Hosp.  Rep. 
vol.  ii. 

(Benjamin  Phillips.) 

BLOOD,  (Gr.  afyta.  Lat.  sanguis.  Yr.sang. 
Germ.  Elut.  Ital.  sangue).  This  is  the  title 
given  to  the  peculiar  fluid  which  carries  into 
the  living  tissues  of  animals  the  materials 
necessary  to  the  nutritive  processes  going  on 
within  them. 

The  physical  qualities  of  this  fluid  vary 
extremely ;  among  almost  all  the  lower  animals 
it  is  so  far  from  resembling  what  we  are  accus- 
tomed to  regard  as  essential  to  the  blood  in 
man  and  the  vertebrata  generally,  that  its 
nature  is  at  first  sight  apt  to  be  mistaken,  and 
we  cannot  be  surprised  that  the  inferior  tribes 


of  creation  should  have  been  long  supposed 
to  be  without  blood.  In  the  mammalia,  birds, 
reptiles,  fishes,  and  several  of  the  anrielida, 
the  blood  is  of  a  red  colour  ;  among  the  whole  of 
the  in  vertebrata,  a  few  of  the  annelida  excepted, 
it  is,  on  the  contrary,  nearly  colourless ;  fre- 
quently it  has  a  decidedly  blue  tint,  and  in 
many  instances  it  is  bluish,  greenish,  or  yel- 
lowish. A  celebrated  chemist  (Berzelius)  has 
lately  stated  that  the  common  fly  (one  of  the 
insecta)  had  red  blood  in  the  head,  and  colour- 
less blood  in  the  other  parts  of  its  body,  it 
is  true,  indeed,  that  if  the  head  of  one  of  these 
insects  be  crushed,  a  reddish  fluid  is  forced 
out ;  but  this  is  not  blood ;  it  proceeds  from 
the  eyes  of  the  insect,  whose  blood,  in  the  head 
as  elsewhere,  and  among  all  the  other  species 
of  the  genus,  as  well  as  among  the  arach- 
nida,  Crustacea,  and  mollusca,  is  almost  co- 
lourless. 

From  these  differences  in  the  appearance 
of  the  nutrient  fluid,  the  animal  kingdom  has 
been  divided  into  animals  having  red  blood 
and  animals  having  white  blood.  But  these 
modifications  of  colour  are  not  perhaps  of  so 
much  consequence  as  has  commonly  been  be- 
lieved, for  they  are  met  with  among  animals 
having  in  all  other  respects  the  most  striking 
analogy  one  with  another,  as  has  already  been 
seen  in  our  particular  article  on  the  ANNE- 
LIDA. 

The  blood  is  an  opaque,  thickish  fluid,  of  a 
specific  gravity  greater  than  that  of  water.  In 
man  its  density  varies  from  1,052  to  1,057. 
It  has  a  saline  and  rather  sickly  taste,  and 
it  diffuses  a  peculiar  odour,  which  varies 
somewhat  in  different  tribes,  and  occasionally 
in  the  different  sexes  of  the  same  species. 
In  all  the  vertebrata,  it  is,  as  we  have  said, 
red ;  but  the  shade  of  this  colour  varies  in 
different  animals,  as  it  is  familiarly  known  to 
do  in  the  same  animal,  according  as  it  is  ex- 
amined in  its  course  to  the  tissues  which  it  is 
destined  to  supply  with  nourishment,  or  after  it 
has  already  traversed  these,  and  is  returning  to 
the  centre  of  the  circulation ;  the  colour,  how- 
ever, may  be  stated  to  be  generally  deep. 

Examined  by  the  naked  eye,  the  blood  ap- 
pears to  be  perfectly  fluid  and  homogeneous ; 
but  if  it  be  spread  in  a  very  thin  stratum  upon 
the  object  plate  of  a  microscope,  and  viewed 
under  a  lens  having  a  magnifying  power  of 
between  200  and  300,  it  will  be  seen  to  con- 
sist of  two  distinct  and  heterogeneous  parts, 
viz.  a  transparent  yellowish  watery  fluid,  and 
a  number  of  solid  corpuscles,  of  extreme  mi- 
nuteness, suspended  in  this  fluid.  To  the 
fluid  portion,  the  name  serum  is  given;  the 
minute  corpuscles  are  spoken  of  as  the  globules 
of  the  blood. 

The  discovery  of  the  globules  of  the  blood 
is  almost  contemporaneous  with  that  of  the 
microscope;  it  is  due  to  Malpighi  and  to 
Leuwenhoeck.  A  considerable  number  of  ob- 
servers have  since  engaged  in  the  micro- 
scopical study  of  the  blood ;  but  it  is  to  Hew- 
son  and  to  the  Messrs.  Prevost  and  Dumas  that 
science  is  indebted  for  the  most  important  facta 


BLOOD. 


405 


and  the  best  connected  series  of  inquiries  into 
the  composition  and  qualities  of  this  Huid.* 

The  form  of  the  globules  of  the  blood  varies 
in  different  animals,  but  appears  to  be  at  all 
times  essentially  the  same  in  individuals  of 
the  same  species ;  this  at  least  is  the  case  if  we 
except  the  first  periods  of  their  embryotic 
existence ;  for  in  the  embryo  the  globules  have 
been  found  to  be  different  before  the  formation 
of  the  liver,  from  what  they  are  after  the  deve- 
lopment of  this  organ. 

The  globules  of  the  blood  of  all  the  mam- 
malia that  have  been  examined  are  of  a  circu- 
lar shape,  whilst  in  birds,  reptiles,  and  fishes, 
they  are  elliptical;  in  the  invertebrate  animals, 
however,  they  are  again  circular. 

The  whole  of  the  microscopical  observers  of 
modern  times  are  agreed  in  the  above  points;  but 
they  differ  in  opinion  with  regard  to  the  nature 
of  these  bodies.  This  discrepancy,  however, 
does  not  appear  to  us  to  be  owing  so  much  to 
any  optical  illusion  to  which  the  microscope 
exposes  those  who  use  it,  as  to  the  choice  of 
objects  made  by  the  different  observers.  Too 
many  of  them  have  been  satisfied  with  the 
study  of  the  human  blood,  the  globules  of  which 
are  extremely  small  and  always  seen  with  great 
difficulty,  whilst,  had  they  made  use  of  the 
blood  of  certain  animals,  as  of  the  frog,  or,  bet- 
ter still,  of  the  water-newt  (Salamandra  cris- 
tata),  they  would  have  escaped  much  of  the 
uncertainty  that  surrounds  their  conclusions. 

The  globules  of  all  animals  having  red  blood 
are  more  or  less  flattened,  and  in  the  greater 
number  of  cases  they  resemble  a  small  circular 
or  elliptical  disc.  Leuwenhoeck  was  aware  of 
this  fact  in  reference  to  birds,  reptiles,  and 
fishes,  but  he  believed  that  in  the  human  sub- 
ject and  the  other  mammalia  these  bodies  were 
spherical.f  This  error,  which  was  sanctioned 
by  Fontana  and  various  others  of  the  older 
observers,  and  has  even  very  recently  been 
adopted  by  Sir  E.  Home  and  M.  Bauer, J 
was,  however,  completely  refuted  by  Hewson, 
Prevost  and  Dumas,  Hodgkin  and  Lister, 
Miiller,  Sec.;  my  own  observations  also  con- 
firm the  conclusions  of  these  physiologists, 
and  even  go  to  prove  that  the  globules  of  the 
blood  in  the  invertebrata  have  the  general  form 
of  flattened  vesicles. 

The  greater  number  of  observers  appear  to 
think  that  the  whole  of  the  globules  of  the 
blood  of  any  animal  are  of  the  same  dimen- 
sions. When  blood  in  which  these  globules 
are  very  minute  is  examined,  and  a  low  mag- 
nifying power  is  employed,  it  is  quite  true 
that  no  perceptible  difference  in  point  of  size 
can  be  detected ;  but  by  estimating  the  mag- 
nitudes of  a  great  number  of  these  globules  com- 
paratively and  under  a  powerful  microscope, 
I  have  satisfied  myself  that  they  differed  in  size 


*  Vide  Hewson  on  the  Blood,  and  Prevost  and 
Dumas,  Examen  du  Sang  et  de  son  action  dans  Ics 
diverses  phenomenes  de  la  Vie,  in  Biblioth. 
I'nivers.  de  Geneve,  t.  xvii. 

t  Philos.  Trans.  No.  165,  1684,  p.  788. 

t  Ibid.    1818. 


in  the  same  individual.  Among  the  lower 
animals,  the  river-crab  (axtacusjluviatilis)  for 
instance,  it  is  by  no  means  difficult  in  the  same 
drop  of  blood  to  perceive  globules  of  very  dif- 
ferent dimensions ;  and  although  this  inequality 
is  much  less  remarkable  among  the  higher  ani- 
mals, I  may  affirm  that  it  exists.  Thus,  in  the 
same  drop  of  a  frog's  blood,  I  have  seen  globules 
that  differed  from  one  another  in  the  proportion 
of  39  to  45,  without  my  being  able  to  ascribe 
these  variations  of  diameter  to  any  circumstance 
connected  with  my  mode  of  observing,  or  to 
any  optical  illusion  :  the  globules  were  spread 
in  a  single  layer  upon  the  object  plate,  and  so 
close  together  as  to  be  exactly  within  the  focus 
of  the  instrument.  Their  apparent  diameters, 
I  may  state,  were  estimated  by  tracing,  with 
the  assistance  of  the  camera  lucida,  the  out- 
lines of  their  images,  upon  a  board  eight 
inches  distant  from  the  eye-piece.  I  found 
corresponding  differences  of  dimension  among 
the  globules  of  the  human  blood  ;  in  the  same 
drop  1  have  measured  several  which  were  to 
each  other  in  the  ratio  of  112  to  140  :  in  ge- 
neral, however,  the  differences  are  scarcely 
appreciable. 

The  globules  of  the  blood  appear  to  be 
identical  in  every  part  of  the  circulating  sys- 
tem, and  hitherto  no  difference  in  their  size  or 
shape  has  been  detected  in  individuals  of  the 
same  species,  though  of  different  ages  and 
sexes. 

It  was  long  found  a  matter  of  considerable 
difficulty  to  determine  the  precise  diameter  of 
the  globules  of  the  blood ;  we  consequently 
find  marked  discrepancies  in  the  conclusions 
come  to  by  different  microscopists.  At  the 
present  day,  however,  and  since  our  means  of 
observation  have  been  improved,  the  estimates 
have  become  gradually  less  and  less  discordant, 
and  therefore  may  be  held  worthy  of  the 
greater  confidence. 

From  a  very  great  number  of  measurements 
taken  by  means  of  the  process  of  M.  Amici 
(with  the  camera  lucida),  and  under  a  mag- 
nifying power  of  900,  I  have  obtained  as  the 
mean  term  of  the  diameter  of  the  globules  of 
the  human  blood  ^  of  a  line  (English,)  or  in 
decimal  fractions  0,00030  of  a  line.  But  as  I 
have  already  said,  I  have  found  considerable 
variety  in  the  sizes  of  the  globules;  some, 
and  these  were  the  largest,  were  35  ten  thou- 
sandth parts  of  a  line,  and  others,  the  smallest, 
no  more  than  28  ten  thousandths  of  a  line  in 
diameter. 

These  estimates  accord  very  nearly  with  the 
last  admeasurements  published  by  M.  Dumas, 
and  taken  by  a  different  method.  He  gives 
31  ten  thousandths  of  a  line  as  the  mean  dia- 
meter of  a  globule  of  the  human  blood  accord- 
ing to  his  latest  observations.* 

The  conclusions  come  to  by  Dr.  Hodgkin 
and  Mr.  Lister  are  also  very  nearly  the  same, 
these  observers  estimating  the  diameter  of  the 


*   Annalcs    des    Sciences    NalureHes,  torn.  xii. 
p.  59. 


406 


BLOOD. 


globule  of  the  human  blood  at  33  ten  thou- 
sandths of  a  line.  These  dimensions  exceed, 
it  is  true,  the  mean  of  the  measurements  I 
have  taken,  but  they  are  still  within  the  limits 
of  the  individual  variations  which  I  have  en- 
countered among  these  corpuscles;  and  as 
the  physiologists  quoted  do  not  say  whether 
their  estimate  was  made  from  the  mean  of  a 
number  of  observations,  or  from  the  measure- 
ment of  only  a  few  globules  more  apparent 
than  the  rest,  it  is  impossible  for  me  to  deter- 
mine whence  this  discrepancy  in  our  conclu- 
sions arises,  whether  from  actual  varieties, 
from  the  manner  of  proceeding  in  determining 
the  magnifying  power  of  the  microscope,  or 
from  an  error  in  taking  the  limits  of  the  image 
projected  by  the  camera  lucida.* 

The  observations  made  some  twelve  years 
ago  by  Messrs.  Prevost  and  Dumas  do  not 
differ  from  the  measurements  already  given. 
The  diameters  they  then  assigned  to  the  glo- 
bules of  the  blood,  amounted  to  33  ten  thou- 
sandths of  a  line  (^j  of  a  millimetre);  but  the 
magnifying  powers  they  at  that  time  employed 
did  not  exceed  300,  and  consequently  the 
difference  between  the  diameter  of  a  globule 
31575ffi5wtns  of  a  line  and  one  3677u^ogths  of 
a  line  might  fail  to  be  detected ;  further,  the 
errors  which  arise  from  the  determination, 
always  somewhat  arbitrary,  of  the  limits 
of  the  image,  are  sufficient  to  explain  such 
slight  differences  as  occur  in  the  results  of 
these  very  delicate  observations.  We  must  also 
add  that  Messrs.  Prevost  and  Dumas  at  this 
time  made  use  of  a  method,  much  less 
accurate  than  the  camera  lucida,  for  taking 
the  apparent  diameters  of  objects  under  the 
microscope,  causing  the  image  seen  in  the 
instrument  with  the  right  eye  to  coincide  with 
the  divisions  of  a  scale  placed  laterally  under 
the  left  eye.  We  therefore  believe  our- 
selves justified  in  the  preference  we  accord 
to  the  more  recent  observations  of  these  gentle- 
men. 

^  The  late  Captain  Kater,  at  the  request  of 
Sir  E.  Home,  also  made  some  observations 
with  a  view  to  determine  the  diameter  of  the 
globules  of  human  blood,  taking  his  measure- 
ments in  the  manner  formerly  employed  by 
Messrs.  Prevost  and  Dumas,  but  making  use 
of  a  power  not  higher  than  200,  by  which  the 
chances  of  erroneous  conclusions  were  greatly 
increased.  His  first  observation,  nevertheless, 
comes  extremely  near  what  we  are  inclined  to 
regard  as  the  truth  (22TgLroths  of  a  line);  a  se- 
cond observation,  however,  gives  a  much  smaller 
diameter  (.IS^Uw  of  a  line),  but  it  is  possible 
that  in  this  case  the  observer  may  have  taken 
his  measurements  from  a  globule  divested  of 
its  colouring  matter,  or  perhaps  from  one  of  the 
albuminous  globules  which  abound  in  the 

Vide,  Some  microscopical  Observations  on  the 
Blood,  &c.  in  Philos.  Mag.  Aug.  1827. 


serum,  and  which  are  in  fact  very  nearly  of 
the  dimensions  indicated.* 

Mr.  Bauer  and  Sir  E.  Home  had  pre- 
viously assigned  SB-j^^tlis  of  a  line  as  the  di- 
ameter of  these  globules  ;  but  their  obser- 
vations having  been  made  with  the  ordinary 
micrometer  are  necessarily  defective,  inasmuch 
as  the  globules  placed  upon  this  instrument, 
and  the  divisions  drawn  on  its  surface,  can 
never  be  simultaneously  in  the  focus  of  the 
object  glass.f 

Dr.  VVollaston  held  that  the  globules  of  the 
human  blood  did  not  exceed  20-,D^5ths  of  a  line 
in  diameter,  which  is  considerably  different 
from  our  mean ;  and  Dr.  Young  did  not  esti- 
mate them  at  more  than  16  i^ootns  °^a  line.J 
It  is  also  possible  that  both  of  these  eminent 
individuals  have  measured  the  central  nuclei  of 
globules  divested  of  their  vesicular  envelope. 
The  results  just  specified  having,  farther,  been 
come  to  by  the  aid  of  the  eriometer,  an  in- 
strument which  we  have  searched  for  in  vain 
through  all  the  instrument-makers  and  col- 
lections of  philosophical  apparatus  in  Paris, 
and  as  we  are  altogether  ignorant  of  the 
degree  in  which  its  indications  may  be  relied 
on,  we  cannot  discuss  these  conclusions  with 
an  adequate  knowledge  of  the  elements  from 
which  they  are  derived.  As  to  the  measure- 
ments published  long  ago  by  Jurine,  they  are 
so  discordant  that  no  confidence  can  be  placed 
in  them  ;  the  first  diameter  he  assigned  to  the 
globules  of  the  blood  was  IQ-jg^jths,  the  se- 
cond Sl-jj^ths  of  a  line. 

From  all  that  has  gone  before,  then,  and 
particularly  from  those  researches  which  have 
been  conducted  under  circumstances  the  most 
favourable  to  accurate  conclusions,  we  may 
assume  the  mean  diameter  of  the  globules  of 
the  human  blood  to  be  about  the  Sl^^lns, 
or  in  vulgar  fractions  the  g^th  part  of  a  line. 

Messrs.  Prevost  and  Dumas  have  given  the 
dimensions  of  the  globules  of  the  blood  of  a 
great  number  of  other  vertebrate  animals ;  in 
these  observations  they  employed  the  same 
means  of  estimating  the  diameters  as  in  their 
earliest  researches  on  the  size  of  the  globules 
of  the  human  blood,  so  that  to  me  their  valu- 
ations appear  to  fall  somewhat  short  of  the 
truth.  This  slight  presumed  inaccuracy,  how- 
ever, scarcely  detracts  from  the  interest  of  the 
general  results ;  for  the  measurements  being 
all  taken  by  the  same  means  and  therefore 
comparable  one  with  another,  are  adequate  to 
show  in  the  clearest  light  the  differences  that 
occur  in  the  dimensions  of  these  corpuscles  in 
different  animals.  The  following  is  the  table 
of  admeasurements  given  by  the  physiologists 
quoted. 


*  Vide  Additions  to  the  Croonian  Lecture, 
Philos.  Trans.  1818. 

t  Loc.  cit. 

j  Young,  Elem.  of  Med.  Literature,  8vo. 
Lond.  1818. 


BLOOD. 


407 


NAMES  Of  THE  ANIMALS. 

Diameter  of  the  globules 
in  vulgar  fractions  of  an 
English  line. 

Diameter  of  the  globules  in 
decimal  fractions  of  an 
English  line. 

MAMMALIA. 
Man     ....               .     . 

1J 

l| 

« 

d 

5J 

d 
ii 

Great  diam. 
ifa 

4 

505 

& 

db 

*> 

ill 

& 

Tb 
lk 
1*» 

A 

Ai 

T^ 

B 

5 
i 

15 

I 

3 
3 

Small  diam, 
lb 

id. 

id. 
id. 

id. 
id. 

* 

& 
5k 
ib 

£ 
ib 

ib 

3^3 

0,00 

0,00( 
0,00( 

0,00( 

0,00( 
0,00( 

o,ooc 

Great  diam. 
0,000526 

0,000500 

0,000488 
0,000463 

0,000458 
0,000316 

0,000757 
0,000657 
0,000598 
0,000658 
0,000598 

0,001132 
0,000877 

0,000526 

3231 

)328 
)335 

)220 

)196 

)181 
>104 

Small  diam. 
0,000231 

id. 

id. 
id. 

id. 
id. 

0,000512 
0,000316 
0,000342 
0,000316 
0,000354 

0,000704 
0,000526 

0,000319 

Canis  f'amiliaris    L 

Sus  scrofa,  L  

Mus  panel  lus.  L  
jblus  uvcllunus,  L  

.    V 

Lepus  cuniculus    L. 

Erinaceus  Europcus,  L  
Si  in  iu  Subfca    L           .           .           . 

•     *J 

E(JUUS  asinus,  L  

Felis  cut  us   L 

> 

Mus  musculus 

j 

Equus  hybridus,  L  

| 

JBos  taurus,  L  

> 

Ovis  aries,  L  

\ 

Capra  hircus,   L  

,  > 

Cervus  eluphus,  L. 

AVES. 
Strix  flammed,   L  

.  ) 

Columba  domestica    L 

Didus  ineptus,    L  

.  ) 

Anas  boschaSy   L. 

Pavo  cristatus,  L  

Anas  anser,  L  

"\ 

Corvus  cor  ax,  L  

) 

Fringilla  carduelis,  L  
Fringilld  domestica     

1 

Par  us  major,   L.    . 

REPTILIA. 
Testudo  terrestris,  L  
Colubra  bcrus,  L  
Anmtis  fragilis.    L. 

•      • 

Coluber  Razomouskii  

Lacerta  grisea,   L. 

Salamandra  cincta,   L  

> 

Salamandra  cristata,    L. 

j 

Rana  bufo,   L  

.  "V 

Rana  esculenta,   L. 

< 

Rana  temporaria,  L  

s 

PISCES. 
Gadus  lota,   L  

•v 

Cj/prinus  phoscinus,  L  
Cobitis  barbatula,   L  

•1 

From  my  own  observations  I  am  inclined 
to  think  that  the  globules  of  the  blood  of  the 
frog  have  a  mean  long  diameter  of  about 
96i5gifi5ths  of  a  line ;  but  the  individual  differences 
observable  among  the  several  globules  ranged 
between  87-^^  and  lOO^gths  of  a  line.  In  the 
blood  of  the  water-newt  (Salamandra  cristata) 
I  have  obtained  in  my  measurements  of  the 
long  diameters  of  the  globules  the  following  ex- 


treme individual  varieties:  minimum 
of  a  line,  maximum  127-n5^roths. 

The  outline  of  the  globules  in  all  the  verte- 
brate animals  is  extremely  well  defined ;  but 
they  are  readily  deformed  or  put  out  of  shape. 
Even  during  life  their  pressure  mutually,  or 
the  pressure  they  experience  between  the  cur- 
rents in  which  they  move  and  the  parietes  of 
the  vessels  against  which  they  are  driven,  suf- 


408 


BLOOD. 


fices  to  alter  their  form ;  they  are  then  fre- 
quently seen  to  become  elongated,  to  bend, 
in  a  word,  to  alter  their  figure  considerably ; 
but  they  are  extremely  elastic,  and  readily  and 
soon  resume  their  pristine  state. 

Among  the  invertebrate  animals  the  globules 
of  the  blood  are  much  less  regular  in  their 
forms.  Their  surface  is  uneven  and  tubercu- 
lated,  like  that  of  a  raspberry ;  their  contour 
is  extremely  variable ;  they  change  their  figure 
with  the  greatest  facility,  and  their  size 
is  considerable.  In  the  blood  of  the  river 
crab  for  example  (astacus  fluviatilis)  I  have 
found  their  mean  diameter  to  be  70^usihs 
of  a  line.  Several,  however,  were  measured 
which  were  no  more  than  CTf^oths  of  a  line 
across,  and  others  which  were  as  much  as 
72^5^8.  In  the  oyster  I  have  detected  still 
wider  differences  in  the  size  of  the  globules  of 
the  blood.  In  the  same  drop  of  this  creature's 
blood  I  found  some  globules  60lu^55ths,  others 
only  54-jg^oths,  and  some  no  more  than 
40^1^118  of  a  line  in  diameter. 

It  is  well  ascertained  that  the  blood  differs 
during  the  earlier  periods  of  embryotic  existence 
from  what  it  is  in  after  life.  Messrs.  Prevost 
and  Dumas  have  shown  that  the  globules  of 
the  blood  in  the  chick  in  ovo  are  circular  at 
first,  and  only  become  elliptical  at  the  period 
when  the  liver  is  developed.*  And  M.  Prevost 
found  that  in  the  foetus  of  the  goat  these 
corpuscles  were  at  first  the  double  in  diameter 
of  those  in  the  adult  animal  .f 

The  structure  of  the  globules  of  the  blood, 
as  well  as  their  magnitude,  has  been  a  subject 
of  great  variety  of  opinion.  The  differences 
in  the  conclusions,  however,  appear  to  me  to 
depend  principally  on  the  circumstances  in 
the  mode  of  experimenting.  Delia  Torre  and 
Styles  believed  that  the  globules  of  the  blood 
were  perforated  in  the  centre  and  fashioned 
like  rings.  When  they  are  examined  with 
lenses  of  low  magnifying  power,  they  look  like 
small  black  points;  when  viewed  under  an 
instrument  rather  more  powerful,  they  assume 
the  appearance  of  a  white  circle  with  a  black 
point  in  its  middle ;  this  is  evidently  what  has 
given  rise  to  the  opinion  we  have  quoted  ;  but 
the  appearance  in  question  by  no  means  de- 
pends on  the  existence  of  a  central  hole  in  the 
globules ;  it  is  merely  the  effect  of  the  light ; 
for  by  using  a  magnifying  power  of  300  or  400, 
the  central  point  assumes  the  appearance  of  a 
luminous  spot,  and  by  varying  the  position  of 
the  globule,  as  well  as  the  direction  of  the 
rays  of  light,  the  observer  may  easily  convince 
himself  that  the  globules  are  entire.  Hewson, 
to  whom  we  are  indebted  for  so  many  good 
observations  on  the  blood,  was  the  first  who 
arrived  at  accurate  conclusions  in  regard  to  its 
globules.  He  considered  them  as  flattened 
vesicles,  in  the  interior  of  which  there  is  a 
central  corpuscle  or  nucleus.  The  accuracy  of 
this  opinion,  which  has  been  maintained  in  our 

*  Mem.   sur   le    developpement   du   Coeur,    &c. 
Annales  des  Sciences  Nat.  1  Serie.,  t.  iii. 
•j-  Ann.  des  Sciences  Nat.  t.  iv. 


own  day  by  Messrs.  Prevost  and  Dumas  and 
others,  has  been  called  in  question  by  Dr.  Hodg- 
kin  and  Mr.  Lister ;  nevertheless  to  me  it  ap- 
pears to  be  founded  on  unquestionable  data. 
In  studying  the  blood  of  the  Reptilia,  in  which 
the  globules  are  of  very  considerable  magni- 
tude, Messrs.  Prevost  and  Dumas  have  even 
seen  the  outer  envelope  of  these  corpuscles 
tear,  and  expose  the  central  nucleus  naked.  In 
1826  I  myself  observed  that  by  acting  with 
a  little  weak  acetic  acid  on  the  globules  of  the 
blood,  previously  placed  on  the  object-plate 
of  a  microscope,  they  are  very  speedily  stripped 
of  their  envelope,  and  their  central  nucleus  is 
obtained  isolated.*  Professor  Miiller/t  who 
does  not  appear  to  have  been  acquainted  with 
this  observation  of  mine,  has  lately  arrived  at 
the  same  conclusions,  and  has  varied  his  ex- 
periments in  such  wise  as  to  place  the  results 
that  follow  from  them  in  the  clearest  possible 
light.  I  shall  only  further  add  that  at  the 
moment  of  writing  this  article  I  have  again 
assured  myself  of  the  facts  as  stated,  by  sub- 
jecting the  blood  of  the  river-crab  and  that  of 
the  frog  to  renewed  examination. 

The  existence  of  a  solid,  white,  central 
nucleus  in  the  globules  of  the  blood  conse- 
quently appears  to  me  to  be  completely  de- 
monstrated ;  and  there  is,  further,  every  reason 
to  believe  that  the  peripheries  of  these  cor- 
puscles are  membranous  vesicles  formed  of 
the  matter  which  gives  the  blood  its  peculiar 
colour,  or  rather  that  they  enclose  this  colour- 
ing matter  between  their  inner  surfaces  and  the 
central  nuclei.  This  vesicular  part  of  the  glo- 
bule is  very  elastic  :  whilst  engaged  in  examin- 
ing the  capillary  circulation  in  the  lungs  of 
the  water-newt,  Messrs.  Prevost  and  Dumas 
frequently  saw  the  globules  change  their  figure 
under  the  pressure  of  the  moving  column  of 
fluid,  and  mould  themselves  in  some  sort 
upon  the  parts  that  opposed  their  advance, 
but  they  resumed  their  original  form  the  instant 
they  escaped  from  the  influence  of  the  unequal 
pressure.}  In  general  the  tegumentary  vesicle 
is  collapsed  upon  the  central  corpuscle,  and 
thus  forms  a  kind  of  disc  of  different  degrees  of 
thinness  near  the  edges,  but  plump  or  filled  out 
towards  the  middle.  By  observing  the  globules 
of  the  blood  of  the  frog  and  water-newt  in  diffe- 
rent positions,  the  existence  of  this  central  tumi- 
dity may  be  so  positively  ascertained  as  to  be  be- 
yond the  reach  of  farther  doubt;  but  in  the  hu- 
man blood,  the  globules  of  which  are  extremely 
small  and  almost  entirely  occupied  by  the 
central  nucleus,  it  is  more  difficult  to  be  satis- 
fied of  its  occurrence;  and  Dr.  Young  has 
even  been  led  to  think  that  these  globules 
are  discs  concave  on  both  sides,  an  opinion 
which  has  been  revived  and  advocated  anew 
by  Dr.  Hodgkin  and  Mr.  Lister.  The  ap- 


*  Mem.  sur  les  tissus  :  Ann.  des  Sciences  Natur. 
t.  ix. 

t  Observations  sur  1'analyse  de  la  Lymphe  du 
Sang,  &c.  Annales  des  Sciences  Naturelles,  2  Serie, 
Zoologie,  t.  i.  p.  559. 

$  Vide  Magendie,  Physiologic,  t.  ii. 


BLOOD. 


409 


pearance  or  disposition  of  the  globules  in 
question,  when  it  occurs,  seems  to  me  to 
depend  on  an  alteration  of  these  corpuscles. 
In  examining  the  blood  of  frogs  diluted  with 
thin  syrup,  the  globules  occasionally  appeared 
to  me  to  become  turgid,  but  not  to  be 
distended  equally  in  every  part;  the  exterior 
vesicle  then  remained  attached  to  the  centre  of 
the  internal  nucleus,  whilst  it  became  puffed 
all  around.  I  have  seen  a  globule  thus  altered 
in  its  form,  presenting  three  very  distinct  en- 
largements in  the  course  of  its  long  diameter, 
the  two  lateral  of  which  exceeded  the  median 
one  in  extent.  I  should  therefore  be  led  to 
imagine  that  by  the  effect  of  an  endosmosis 
these  vesicles  may  occasionally  absorb  the 
water  of  the  serum,  and  that  this  fluid,  accu- 
mulating around  the  central  nucleus,  without, 
however,  separating  this  corpuscle  from  its 
envelope,  gives  to  the  globule  in  general  the 
form  of  a  biconcave  disc,  as  described  by  Dr. 
Young.  This  appearance,  which  is  very  com- 
mon in  the  human  blood,  agrees  extremely 
well  with  the  description  of  Dr.  Hodgkin  and 
Mr.  Lister,  but  we  do  not  imagine  that  this  is  the 
normal  condition,  and  we  are  persuaded  that 
if  these  very  scrupulous  observers  would  but 
extend  their  inquiries  to  the  blood  of  those 
animals  in  which  the  globules  are  most  easily 
studied,  they  would  return  to  and  espouse 
the  opinions  of  Ilewson  and  of  Prevost  and 
Dumas  in  regard  to  the  particular  point  at 
issue. 

In  the  normal  state,  the  membranous  vesicle 
of  the  globules  of  the  blood  appears  perfectly 
smooth  among  vertebrate  animals ;  but  among  the 
invertebrata  its  surface  is  uneven  and  nodulated 
like  that  of  a  raspberry,  as  we  have  already 
said.  Hewson,  however,  observed  that  when 
the  blood  of  the  vertebrata  began  to  putrefy, 
the  globules  then  presented  an  appearance 
analogous  to  what  we  have  remarked  in  those  of 
the  Crustacea  and  mollusca.  In  the  mammalia 
the  central  nucleus  is  circular  and  depressed, 
and  in  all  this  class  of  animals  it  appears  to  be 
similar  in  size.  In  the  oviparous  vertebrata,  it 
is  on  the  contrary  elliptical  in  figure,  though, 
according  to  Messrs.  Prevost  and  Dumas,  it 
acquires  this  figure  in  consequence  of  a  par- 
ticular substance  being  fixed  around  it,  itself 
being  in  reality  circular,  as  among  the  mam- 
malia. 

It  frequently  happens  that  other  smaller 
corpuscles  than  the  globules  of  which  we  have 
treated  hitherto  are  observed  swimming  in  the 
serum.  These  are  of  a  whitish  colour  and  simi- 
lar to  the  molecules  that  occur  in  almost  all 
the  fluids  of  the  animal  economy.  The  resem- 
blance that  exists  between  these  corpuscles  and 
the  central  nuclei  of  the  proper  globules  of 
the  blood  might  lead  to  the  belief  that  they 
were  nothing  more  than  the  central  nuclei 
divested  of  their  coloured  envelope ;  but  in 
several  of  the  inferior  tribes,  as  the  river-crab 
and  certain  mollusca,  in  the  blood  of  which 
they  occur  in  very  considerable  numbers,  the 
central  nuclei  of  the  globules  are  much  larger, 
and  it  is  impossible  to  confound  the  two  toge- 


ther. These  then  are  to  be  regarded,  not  as 
globules  of  the  blood,  properly  so  called, 
altered  in  any  way,  but  as  globules  of  albumen 
or  fibrine.  These  substances,  in  fact,  have 
always  the  appearance  of  being  made  up  of 
circular  corpuscles  of  extreme  minuteness  when 
by  any  means  they  are  brought  into  the  solid 
state;  and  we  are  led  to  believe  that  even 
when  dissolved  or  suspended  in  water  they 
still  preserve  this  peculiar  disposition,  and  only 
escape  detection  under  the  microscope  by  their 
dissemination  and  transparency. 
To  recapitulate,  then,  we  find  : — 
1st.  That  the  globules  of  the  blood  are  mem- 
branous sacs  inclosing  a  solid  flattened  nu- 
cleus in  the  form  of  a  disc,  in  their  interior. 

2d.  That  their  form  and  their  dimensions 
vary  among  animals  of  different  species,  but 
that  in  the  same  animal  they  all  bear  the 
strongest  resemblance  to  one  another. 

3d.  That  in  the  mammalia  these  corpuscles 
are  circular  and  smaller  than  in  any  other  class 
of  animals. 

4th.  That  in  birds  the  globules  of  the  blood 
are  elliptical  and  larger  than  in  the  mammalia; 
their  dimensions  vary  slightly  in  different 
genera,  but  this  variety  does  not  seem  to  ex- 
tend further  than  to  the  admeasurements  of 
their  long  diameters. 

5th.  That  in  vertebrate  animals  with  cold 
blood  the  globules  are  also  elliptical,  but  that 
their  dimensions  are  much  greater  and  vary 
more  extensively  in  different  classes  ;  reptiles, 
more  especially  the  batrachia,  are  of  all  animals 
those  in  which  the  globules  of  the  blood  are 
the  largest. 

6th.  That  in  the  invertebrata  the  globules  of 
the  blood  are  more  or  less  regularly  circular  in 
shape,  and  are  also  of  very  considerable  dimen- 
sions. 

It  appears  to  be  especially  owing  to  the 
presence  of  the  globules,  the  common  physical 
properties  of  which  we  have  thus  far  studied, 
that  the  blood  owes  its  power  of  arousing  and 
keeping  up  vital  motion  in  the  animal  economy. 
We  observe,  in  fact,  that  if  an  animal  be  bled 
till  it  falls  into  a  state  of  syncope,  and  the 
further  loss  of  blood  is  not  prevented,  all 
muscular  motion  quickly  ceases,  respiration  is 
suspended,  the  heart  pauses  from  its  action, 
life  is  no  longer  manifested  by  any  outward 
sign,  and  death  soon  becomes  inevitable ;  but 
if,  in  this  state,  the  blood  of  another  animal 
of  the  same  species  be  injected  into  the  veins 
of  the  one  to  all  appearance  dead,  we  see  with 
amazement  this  inanimate  body  return  to  life, 
gaining  accessions  of  vitality  with  each  new 
quantity  of  blood  that  is  introduced,  by-and- 
bye  beginning  to  breathe  freely,  moving  with 
ease,  and  finally  walking  as  it  was  wont  to  do, 
and  recovering  completely.  This  operation, 
which  is  known  under  the  name  of  transfusion, 
proves  better  than  all  that  can  be  said  the 
importance  of  the  action  of  the  globules  of  the 
blood  upon  the  living  tissues;  for  if,  instead  of 
blood,  serum  only,  deprived  of  globules,  be 
employed  in  the  same  manner,  no  other  or 
further  effect  is  produced  than  follows  the  in- 


410 


BLOOD. 


jection  of  so  much  pure  water,  and  death  is 
no  less  an  inevitable  consequence  of  the  he- 
morrhage. 

A  variety  of  other  experiments  upon  trans- 
fusion, for  which  we  are  equally  indebted  to 
Messrs.  Prevostand  Dumas,  show  the  influence 
which  the  form  and  volume  of  the  globules  of 
the  blood  exert  upon  its  physiological  proper- 
ties. If  the  blood  introduced  into  the  veins 
of  a  living  animal  differs  merely  in  the  size, 
not  in  the  form  of  its  globules,  a  disturbance 
or  derangement  of  the  whole  economy  more  or 
less  remarkable  supervenes.  The  pulse  is  in- 
creased in  frequency,  the  temperature  falls 
rapidly,  the  alvine  evacuations  become  slimy 
and  sanguinolent,  and  death  in  fine  generally 
happens  after  the  lapse  of  a  few  days.  The 
effects  produced  by  the  injection  of  blood 
having  circular  globules  into  the  veins  of  an 
animal  the  globules  of  whose  blood  are  ellip- 
tical, (or  vice  versa,}  are  still  more  remarkable ; 
death  then  usually  takes  place  amidst  nervous 
symptoms  of  extreme  violence,  and  comparable 
in  their  rapidity  to  those  that  follow  the  intro- 
duction of  the  most  energetic  poisons. 

We  know  by  observation  and  experiment 
that  it  is  the  blood  that  supplies  the  living 
tissues  with  the  materials  which  they  assimilate 
to  repair  their  losses  resulting  from  the  vari- 
ous processes  of  which  they  are  the  seat,  as 
well  as  to  add  to  their  masses  during  the  period 
of  their  growth;  thus,  when  by  mechanical 
means  we  lessen  in  a  notable  and  permanent 
manner  the  quantity  of  this  fluid  received  by 
any  organ,  we  soon  find  it  declining  in  size, 
and  often  shrinking  almost  to  nothing;  whilst 
on  the  other  hand  we  see  that  the  more  blood 
any  part  receives,  the  more  does  it  tend  to  in- 
crease in  size.  It  has  also  been  demonstrated 
that  it  is  at  the  expense  of  the  blood  that  the 
different  glands  prepare  the  fluids  they  are 
destined  to  secrete,  for  the  ligature  of  the  ves- 
sels which  run  to  one  of  these  organs  is  followed 
by  the  immediate  cessation  of  its  secreting 
function.  From  this  it  became  an  interesting 
question  to  determine  whether  or  not  the  blood 
contains,  ready  formed,  the  various  substances 
of  which  these  tissues  and  these  secreted  fluids 
are  composed,  and  if  the  organs  it  traverses 
do  anything  more  than  merely  separate  these 
from  its  mass,  or  whether  the  general  nutrient 
fluid  only  supplies  to  the  different  parts  of  the 
economy  the  primary  elements  necessary  to  the 
formation  of  the  substances  of  which  we  have 
spoken,  which  would  then  be  originated  by 
the  tissues  or  glands  in  which  they  are  encoun- 
tered. To  resolve  this  question,  it  became 
necessary  to  contrast  the  chemical  composition 
of  the  tissues  and  fluids  of  the  economy  with 
that  of  the  blood,  and  to  ascertain  whether  the 
last-named  fluid  contained  all  the  variety  of 
substances  which  are  met  with  elsewhere  in  the 
animal  organization. 

This  very  important  part  of  organic  chemistry 
is  not  yet  sufficiently  advanced  to  enable  us  com- 
pletely to  answer  the  question  :  all  we  know, 
however,  goes  to  prove  that  the  component 
parts  of  the  tissues  and  secreted  fluids  exist 


in  the  blood  ready  formed,  and  are  only  sepa- 
rated from  its  general  mass  by  the  organs  which 
at  first  sight  seem  to  produce  them.  In  the 
blood  we  discover — 1st,  water,  an  element 
which  enters  in  large  proportion  into  the  com- 
position of  all  the  fluids,  and  even  forms  a 
considerable  item  in  the  constitution  of  all  the 
tissues  :  2d,  fibrine,  which  forms  the  basis 
of  the  muscles  :  3d,  albumen,  which  is  met 
with  in  variable  but  still  considerable  quantities 
in  the  brain,  cellular  substance,  membranes 
generally,  and  in  the  greater  number  of  the 
secreted  fluids  which  are  not  excrementitious : 
4th,  a  fatty  phosporated  matter,  which  enters 
into  the  composition  of  the  nervous  system : 
5th,  a  peculiar  colouring  matter  of  a  yellow 
hue,  which,  slightly  modified,  is  perchance  the 
same  as  the  pigmentum  nigrum  of  the  choroid 
coat  of  the  eye,  and  of  melanosis  :  6th,  phos- 
phate of  lime  and  phosphate  of  magnesia, 
salts  which  form  the  inorganic  basis  of  the 
bones :  7th,  alkaline  salts,  which  are  met 
with  in  almost  all  the  fluids  of  the  body  :  8th, 
cholesterine,  a  peculiar  fatty  matter  existing 
very  abundantly  in  the  bile :  9th,  urea,  a 
substance  characteristic  of  the  urine  :  lastly, 
various  other  matters  more  or  less  accurately 
defined. 

Under  ordinary  circumstances  our  means  of 
analysis  are  inadequate  to  demonstrate  the 
presence  of  urea  in  the  blood ;  but  if  the  ac- 
tion of  the  organs  destined  to  separate  this 
substance  from  its  current  in  proportion  as  it  is 
formed,  be  arrested,  the  amount  contained 
goes  on  increasing  continually,  so  that  before 
long  it  becomes  easy  to  distinguish  it.  Messrs. 
Prevost  and  Dumas  have  shown  that,  after  the 
extirpation  of  the  kidneys,  the  blood  always 
contains  urea  in  appreciable  quantity.*  This 
experiment,  the  results  of  which  have  been 
confirmed  by  Messrs.  Vauquelin  and  Sega- 
las,  is  of  the  highest  importance,  and  shows 
that  if  we  have  hitherto  failed  to  discover 
uric  acid,  caseum,  and  the  other  compo- 
nent elements  of  the  principal  fluids  in 
the  blood,  we  are  not,  therefore,  to  conclude 
that  they  do  not  exist  there;  analogy  would 
even  lead  us  to  infer  that  they  are  actually 
present,  and  that  if  we  were  to  interrupt 
the  different  glands  in  the  performance  of 
their  functions,  they  would  be  discovered 
in  appreciable  quantity.  Experiments  con- 
ducted in  this  view  would  be  extremely  in- 
teresting. Another  subject  of  inquiry,  too,  not 
less  important,  would  be  to  discover  the  source 
of  the  gelatine  which  forms  the  basis  of  the 
cartilages,  tendons,  ligaments,  &c.  and  which 
does  not  appear  to  exist  in  the  blood. 

The  most  complete  analysis  of  the  human 
blood  we  possess  is  that  published  lately  by 
M.  Lecanu,  a  chemist  of  Paris.f  The  careful 
examination  of  the  blood  of  two  strong  and 
healthy  men  afforded  the  following  results. 


*  Bihl.  Univcrs.  de  Geneve,  and  An.  de  Chemie, 
2de  Srrie,  t.  xxiii. 

t  Journal  dc  Pharm.  No.  ix.  and  x .,  1831. 


BLOOD. 


411 


1st  Analysis. 

3d  Analysis. 

Water 

780.145 

785.590 

Fibrine     .... 

2.100 

3.565 

Albumen  .... 

65.090 

69.415 

Colouring  matter    . 

133.000 

119.626 

Fatty  chrystallizable 

matter  .... 

2.430 

4.300 

Oily  matter   .     .     . 

1.310 

2.270 

Extractive     matters 

soluble  in  alcohol 

and  in  water  .     . 

1.790 

1.920 

Albumen  combined 

with  soda  .     .     . 

1.265 

2.010 

Chloruret     of    po- 

tassium     .     . 

Chloruret  of  sodium 

Alkaline  sub-carbo-     > 

8.370 

7.304 

nates     .... 

Alkaline  phosphates 
Alkaline  sulphates  . 

Sub  -  carbonate    of  " 

lime      .... 

Sub  -  carbonate    of 

magnesia   .     .     . 

Phosphate  of  lime  .    > 

2  100 

1.414 

Phosphate  of  mag- 

nesia    .... 

Phosphate  of  iron    . 

Peroxide  of  iron 

Loss     .               . 

2.400 

2.586 

Total     .     .     . 

1000.000 

1000.000 

Since  the  publication  of  the  preceding  ana- 
lysis, M.  Boudet  has  discovered  a  new  substance 
in  the  serum  of  the  blood,  which  he  denomi- 
nates seroline.  This  is  a  white  slightly  opa- 
lescent substance,  fusible  at  36  cent.,  (about 
94°  Fahr.),  not  forming  an  emulsion  with 
water,  soluble  in  alcohol,  not  saponifiable, 
and  appearing  to  contain  azote.  This  chemist 
has  also  shown  that  the  oily  matter  mentioned 
by  M.  Lecanu  is  a  mixture  of  cholesterine  and 
an  alkaline  soap,  similar  to  that  which  is  met 
with  in  the  bile ;  lastly,  he  has  determined  the 
identity  of  the  fatty  chrystallizable  phosporated 
matter  contained  in  the  blood  with  that  dis- 
covered by  Vauquelin  in  the  brain  (cere- 
brine).* 

The  study  of  the  colouring  matter  of  the 
blood  has  engrossed  a  large  share  of  the  atten- 
tion of  chemists  ;  nevertheless  its  nature  is 
still  very  imperfectly  known.  It  is  very  com- 
monly designated  under  the  name  of  hemato- 
zine  or  hematine,  and  can  be  readily  shown  to 
have  the  greatest  analogy  to  albumen,  from 

*  Ann.  de  Chimie,  2de  Serie,  t.  Hi. 


which  it  is  indeed  always  separated  with  great 
difficulty.  This  matter  is  soluble  in  pure 
water,  insoluble  in  serum  and  in  water  impreg- 
nated with  salt  or  sugar,  coagulable  by  heat, 
capable  of  absorbing  oxygen,  carbonic  acid, 
and  various  other  gases  which  modify  its  colour. 
According  to  M.  Lecanu  the  hematine  of 
chemists  is  a  combination  of  albumen  and  the 
pure  colouring  matter  of  the  blood,  which  he 
proposes  to  designate  globuline.*  But  his 
researches  into  this  delicate  subject  do  not 
seem  to  us  altogether  satisfactory,  and  we  have 
reason  to  believe  that  his  globuline  is  neither 
more  nor  less  than  some  of  the  globules  of  the 
blood  which  have  escaped  the  action  of  the  sub- 
acetate  of  lead  employed  to  precipitate  the  un- 
combined  albumen.  However  this  may  be, 
the  colouring  matter  of  the  blood  after  incine- 
ration leaves  a  large  quantity  of  ashes,  in 
which  a  considerable  proportion  of  oxide  of  iron 
can  be  demonstrated,  to  the  presence  of  which 
several  chemists  have  ascribed  the  red  colour 
of  the  blood ;  such  an  opinion,  however,  does 
not  seem  tenable  at  the  present  day. 

The  experiments  of  Berzelius  have  shown 
that  the  serum  of  the  blood  of  the  ox  does  not 
differ  essentially  from  that  of  the  blood  of  man.-f- 
But  we  are  still  without  comparative  analyses 
of  the  nutrient  fluids  of  the  different  classes  of 
animals.  This  desideratum  has  been  partially 
supplied  in  regard  to  the  vertebrata  by  Messrs. 
Prevost  and  Dumas,  they  having  carefully 
determined  the  proportions  of  water,  and  of 
albumen  contained  in  the  serum,  and  those  of 
the  fibrine,  and  other  solid  parts  which  swim 
suspended  in  this  fluid.  From  these  expe- 
riments we  learn  that  the  composition  of  the 
serum  varies  in  the  same  animal  at  different 
times,  and  that  it  differs  still  more  widely  in 
different  animals,  without  its  being  possible  to 
connect  such  changes  with  the  physiological 
state  of  the  individual.  The  case  is  otherwise, 
however,  as  concerns  the  globules;  in  the 
majority  of  cases  there  exists  a  remarkable 
relation  between  the  quantity  of  these  cor- 
puscles and  the  degree  of  heat  developed  by 
the  vital  actions.  Of  this  we  may  be  easily 
convinced  by  inspecting  the  following  table,  in 
which  Messrs.  Prevost  and  Dumas  have  pre- 
sented us  with  the  comparative  weights  of  the 
solid  particles  (globules  and  fibrine)  contained 
in  1000  parts  of  blood,  with  the  habitual 
temperature  of  different  animals,  taken  in  the 
rectum,  the  number  of  pulsations  of  the  heart 
per  minute,  and  the  number  of  inspirations 
made  in  the  same  interval  of  time. 


*  Ann.  de  Chimie,  2de  Serie,  t.  xlv. 
f  On  animal  fluids,    in   Med.  Chirurg.  Trans, 
vol.  iii. 


412 


BLOOD. 


Names  of  the  Animals. 

Weight  of  the 
solid  particles 
in  1000  parts  of 
blood. 

Composition  of  the 
serum. 

Mean  temperature. 

Normal 
pulse  per 
minute. 

Normal 
number  of 
inspirations 
per  minute. 

Albumen. 

Water. 

BIRDS. 
Pigeon  . 

15.57 

15.71 
15.01 
14.66 
13.26 

14.61 
12.92 
12.80 
12.38 
12.04 
10.20 
9.12 
9.38 
9.20 
9.00 

6.90 
15.06 

6.38 
4.81 
6.00 

55 
75 
99 
66 
68 

92 
100 
100 
74 
96 
93 
99 
109 
99 

50 
96 

77 
69 
100 

945 
925 
901 
934 
932 

908 
900 
900 
920 
904 
907 
901 
891 
901 

950 
904 

923 
931 
900 

42°  centigr. 
41.5 
42.5 

41 

35.5 
39 
38 
37.4 
38.5 
39.2 

38 
36.8 
38 

9.  in  water. 
7.5  that  of  the  air. 

136 
140 
110 

200 

90 
72 
140 
90 
100 
84 

120 
56 

34 
30 
21 

22 

30 
18 
36 
28 
24 
24 

36 
16 

20 
3 

Common  fowl      .     . 
Duck     .... 

Crow     

MAMMALIA. 
Monkey      .... 
Man      .... 

Guinea-pig      .     .     . 
Doe 

Cat 

Goat      

Calf      .     .     . 

Rabbit  

Horse    

Sheep    

REPTILIA. 
Frog      

Tortoise      .     .     ,     . 

FISHES. 
Trout     .     .     . 

Loach    
Eel  . 

From  these  experiments  it  follows  that  of  all 
animals  birds  are  those  whose  blood  is  richest 
in  globules  and  in  fibrine,  as  they  are  those 
also  whose  temperature  is  highest  and  whose 
respiration  is  most  active.  The  blood  of  the 
mammalia  contains  rather  less,  and  there  is  a 
difference  to  be  noted  in  this  respect  between 
the  carnivorous  or  omnivorous  tribes,  and  the 
herbivorous,  the  proportion  of  solid  particles 
being  larger  in  the  two  former  than  it  is  in  the 
latter.  We  see,  indeed,  that  in  man,  the  dog,  and 
the  cat,  they  enter  in  the  proportion  of  twelve 
or  thirteen  per  1000,  whilst  in  the  horse,  sheep, 
calf,  and  rabbit,  they  form  no  more  than  from  the 
seventh  to  the  ninth  per  1000  of  the  general 
weight  of  the  blood.  But  the  number  of  species 
hitherto  examined  is  not  so  considerable  as  to 
enable  us  to  say  that  the  circumstance,  now 
announced,  is  to  be  regarded  in  the  light  of  a 
physiological  law.  Among  the  cold-blooded 
vertebrate  animals  the  blood  becomes  much 
poorer  in  solid  particles ;  the  tortoise,  indeed, 
seems,  from  the  results  in  the  table,  to  form 
an  exception  to  this  fact,  but  the  circumstances 
under  which  the  estimates  were  made  in  regard 
to  it,  and  which  it  would  be  too  long  to  enter 
upon  here,  explain  the  anomaly.* 

The  proportion  of  serum  and  of  solid  parti- 
cles also  presents  considerable  varieties  in  the 
blood  of  different  individuals  of  the  same 
species.  From  the  investigations  of  M.  Lecanu 
we  observe  that  the  proportion  of  water  in  the 
human  blood  varies  from  853  to  778  in  1000, 
and  that  of  the  solid  particles  from  148  to  68. 

The  differences  of  sex   have  also  a  certain 

*  Ann.  de  Cliimic,  t.  xxiii. 


influence  on  the  composition  of  the  blood  :  M. 
Lecanu  found  in  regard  to 

The  blood  of  man  (in  1000  parts.) 

Solid  particles.          Water. 

Maximum     ...  148  805 

Minimum      ...  115  778 

Mean 132  791 

The  blood  of  woman. 

Maximum     ...  129  853 

Minimum     ...  68  790 

Mean 99  821 

The  quantity  of  albumen  did  not  appear  to 
differ  in  the  blood  of  the  two  sexes. 

The  richness  of  the  blood  also  varies  ac- 
cording to  the  temperament  of  individuals, 
as  may  be  seen  by  the  following  table. 

Men. 


Sanguine  tempe- 
rament. 

Lymphatic    tempe- 
rament. 

Maximum 
Minimum 
Mean 

Solid  particles 

Water 

Solid  particles 

Water 

148 
121 
136 

801 
778 
786 

117 
115 

116 

805 
795 
800 

Women. 


Maximum 

129 

796  II 

129 

827 

Minimum 

121 

790 

92 

790 

Mean      . 

126 

793  II 

117 

802 

BLOOD. 


413 


Lastly,  the  composition  of  the  blood  may 
also  vary  in  the  same  individual  according  to 
a  variety  of  circumstances.  Prolonged  absti- 
nence from  diluents,  for  example,  tends  to  di- 
minish the  proportion  of  the  watery  particles 
of  the  blood,  and,  consequently,  to  render  it 
richer  in  nutrient  elements.  Bloodletting  pro- 
duces the  contrary  effect;  not  only  is  the  mass 
of  circulating  fluid  by  this  means  diminished, 
but  it  is  also  rendered  poorer.  Messrs.  Prevost 
and  Dumas  having  bled  a  cat  largely,  found 
its  blood  to  consist  of  791  of  water,  87  of 
albumen,  and  118  of  globules.  Two  minutes 
afterwards  they  repeated  the  bleeding,  and  now 
only  found  116  of  globules,  and  74  of  albu- 
men to  809  of  water ;  after  an  interval  of  five 
minutes  more  the  bleeding  was  repeated  for 
the  third  time,  and  they  found  the  blood  to 
consist  of  829  of  water,  93  of  solid  particles, 
and  77  of  albumen.  M.  Lecanu  obtained 
similar  results  from  the  analysis  of  human 
blood  taken  from  patients  who  had  been  bled 
several  times  in  quick  succession,  or  who  were 
labouring  under  haemorrhagic  affections  ;*  and 
the  circumstance  is  readily  explained,  by  sup- 
posing that  the  diminution  of  the  mass  of 
blood  tends  to  accelerate  absorption,  the  first 
effect  of  which  must  needs  be  to  introduce  a 
much  larger  proportion  of  water  than  of  solid 
particles  into  the  torrent  of  the  circulation. 

In  its  ordinary  state  the  blood  is  always 
fluid,  and  consists,  as  we  have  seen,  of  a 
watery  part,  holding  solid  globules  in  suspen- 
sion; but  under  certain  circumstances  its  physical 
properties  change  completely:  this  happens 
whenever  it  is  withdrawn  from  the  vessels  in 
which  it  is  contained  in  the  bodies  of  living 
animals,  or  in  the  event  of  an  animal  ceasing 
to  exist.  The  blood  left  to  itself  changes  within 
a  few  minutes  into  a  mass  of  a  gelatinous  con- 
sistence, which  gradually  separates  into  two 
parts,  one  fluid,  transparent,  and  of  a  yel- 
lowish colour,  formed  by  the  serum ;  another 
solid,  quite  opaque,  and  of  a  red  colour,  to 
which  the  name  of  cruor,  crassamentum,  or 
clot  is  given. 

The  mode  in  which  this  phenomenon  hap- 
pens, and  the  cause  that  occasions  it,  have 
engaged  the  attention  of  a  great  many  physio- 
logists. The  experiments  of  Hunter  and  of 
many  others  show  that  the  coagulation  of  the 
blood  depends  mainly  on  the  cessation  of  the 
motion  to  which  it  is  constantly  subjected  in 
the  course  of  the  circulation  ;  for  this  condition 
alone  suffices  to  make  it  coagulate  even  in  the 
interior  of  the  vascular  system,  and  we  are  of 
opinion  that  the  great  physiologist  just  quoted 
erred  in  attributing  vital  properties  to  the  blood. 
Rest,  then,  cessation  from  motion,  is  that 
which  contributes  most  generally  and  most 
essentially  to  cause  coagulation  of  the  blood ; 
other  circumstances,  however,  such  as  its 
cooling,  its  being  brought  into  contact  with 
the  air,  &c.  may  also  contribute  to  accelerate 
this  phenomenon,  which  appears,  from  the 
experiments  of  Dr.  John  Davy,  to  be  unac- 
companied with  any  evolution  of  caloric. 


If  a  clot  of  blood  be  gently  kneaded  and 
pressed  under  a  stream  of  water,  it  gradually 
becomes  paler,  and  finally  loses  its  red  colour 
entirely,  the  colouring  matter  being  washed 
away;  what  remains  in  the  hand  is  a  mass  of 
whitish  and  very  elastic  filaments  composed  of 
fibrine.  Or  otherwise,  if,  instead  of  being  left 
at  rest,  a  quantity  of  freshly  drawn  blood  be 
quickly  stirred  with  a  bundle  of  rods,  a  stringy 
mass  of  fibrine  will  be  found  adhering  to  these 
after  a  time,  and  the  blood  thus  treated  will 
not  coagulate.  This  experiment  shows  that  it 
is  to  the  fibrine  that  the  blood  owes  its  pro- 
perty of  coagulating. 

The  filaments  of  fibrine  studied  under  the 
microscope  are  found  to  be  formed  by  the 
aggregation  of  a  multitude  of  white  globules, 
bearing  the  greatest  resemblance  to  the  central 
nuclei  of  the  proper  globules  of  the  blood. 
It  was,  therefore,  natural  to  suppose  that  the 
formation  of  the  coagulum  depended  on  the 
spontaneous  decomposition  of  these  globules 
and  the  aggregation  of  their  internal  corpuscles. 
And  such,  indeed,  is  the  theory  which  Messrs. 
Prevost  and  Dumas  have  given,  and  which 
has  been  adopted  by  the  greater  number  of  the 
physiologists  of  the  present  day.  "  The  at- 
traction," say  they,  "  which  keeps  the  red 
matter  fixed  around  the  white  globules  having 
ceased  along  with  the  motion  of  the  fluid,  these 
globules  are  left  at  liberty  to  obey  the  force 
which  tends  to  make  them  combine  and  form 
a  net-work,  in  the  meshes  or  amid  the  plates 
of  which  the  colouring  matter  is  included  along 
with  a  great  quantity  of  particles  which  have 
escaped  this  spontaneous  decomposition."* 

It  would  appear,  however,  that  this  is  not 
an  exact  explanation  of  the  phenomenon,  for 
Professor  Miiller,  of  Berlin,  has  succeeded  in 
demonstrating  that  the  coagulation  of  the  blood 
is  altogether  independent  of  the  globules,  and 
that  the  fibrine  which  determines  the  pheno- 
menon exists  dissolved  in  the  serum.  By  filter- 
ing with  great  care  the  blood  of  frogs,  diluted 
with  sugar-water,  he  separated  the  globules 
completely  from  the  serum  before  coagulation 
took  place :  the  fluid  part  of  the  blood  alone 
passed  the  filter,  the  solid  particles  remained 
upon  it;  nevertheless,  a  coagulum  formed 
within  the  fluid  after  the  lapse  of  a  few  mi- 
nutes; this,  of  course,  was  colourless  instead 
of  red,  as  it  is  when  the  red  globules  are  en- 
tangled in  the  mass.  This  curious  and  in- 
teresting experiment  does  not  succeed  so  well 
when  human  blood  is  employed,  inasmuch 
as  the  globules,  being  much  smaller  than  those 
of  the  blood  of  the  frog,  pass  along  with  the 
serum  through  almost  any  filter  that  can  be 
used.  Still  Professor  Miiller  has  succeeded 
in  proving  the  existence  of  fibrine  in  the  serum 
by  means  of  the  following  procedure.  If  to  a 
little  blood  contained  in  a  watch-glass  a  few 
drops  of  a  highly  concentrated  solution  of  sub- 
carbonate  of  potash  be  added,  the  coagulation 
of  the  fluid  is  so  much  retarded,  that  the  glo- 
bules have  time  to  sink  to  the  bottom  before  it 
occurs.  When  coagulation  takes  place  at 


*  Journal  de  Pharraacie,  1831. 


*  Ann.  de  Chimie,  t.  23,  p.  51. 


414 


BLOOD. 


length^  the  clot  extends  as  usual  through  the 
whole  mass,  but  it  is  colourless  on  its  upper 
part,  and  only  red  in  the  part  into  which  the 
globules  have  subsided.  Professor  Miiller 
believes  that  the  fibrine  exists  in  a  state  of 
solution  in  the  serum,  an  opinion  which  to  us 
appears  hardly  reconcilable  with  the  known  che- 
mical properties  of  this  substance ;  we  are  more 
inclined  to  suppose  that,  like  the  proper  glo- 
bules, it  is  merely  suspended  in  the  mass  of 
the  blood  in  a  state  of  extreme  subdivision, 
and  possessed  of  transparency  too  perfect  to 
admit  of  its  being  distinguished  amidst  the  sur- 
rounding fluid. 

There  are  circumstances  under  which  the 
blood  only  coagulates  with  difficulty,  or  in 
which  it  even  loses  this  property  entirely.  In 
cases  of  poisoning  with  hydrocyanic  acid,  for 
instance,  the  blood  remains  fluid  and  thick 
after  death ;  the  same  thing  also  occurs  after 
death  from  fever  of  a  typhoid  type,  from 
lightning,  &c. 

Another  phenomenon  presented  by  the 
blood  which  is  of  very  common  occurrence, 
and  depends  on  the  manner  in  which  it  coagu- 
lates, consists  in  the  formation  of  what  is 
called  an  inflammatory  crust  or  buffy  coat : 
the  coagulum,  instead  of  being  uniformly  red, 
then  appears  covered  with  a  greyish  or  yel- 
lowish viscid  and  very  tough  pellicle  of 
various  degrees  of  thickness.  The  pheno- 
menon in  question  is  principally  observed  in 
individuals  labouring  under  acute  inflammatory 
affections  of  the  serous  or  synovial  membranes, 
of  the  substance  of  the  lungs,  Sec.  but  also 
occurs  among  persons  in  good  health,  although 
plethoric.  The  experiments  of  M.  Ratier  go 
to  prove  that  various  circumstances,  altogether 
independent  of  the  physiological  state  of  the 
individual,  may  also  exert  great  influence  on 
the  formation  of  the  buffy  coat :  thus,  c&teris 
paribus,  it  is  more  readily  produced  if  the 
blood  withdrawn  be  received  in  a  deep  and 
narrow  vessel,  and  if  the  opening  in  the  vein 
be  large,  and  the  jet  be  free.  The  cause  of 
the  buffy  coat  has  been  very  satisfactorily  ex- 
plained ;  it  depends  on  the  more  rapid  subsi- 
dence than  usual  of  the  red  globules,  in  con- 
sequence of  which  the  more  superficial  parts 
of  the  coagulum  contain  none.  From  the  ex- 
periments of  Professor  Miiller  it  would  also 
appear  that  this  subsidence  of  the  globules 
takes  place  more  quickly  if  a  thick  solution  of 
gum  be  added  to  the  blood,  so  as  to  increase 
its  density,  whilst,  when  it  is  deprived  of  its 
fibrine  by  stirring  with  rods,  these  bodies 
remain  for  a  very  long  time  suspended.  Now 
it  follows,  from  the  investigations  of  Sir  C. 
Scudamore,  that  buffy  blood  contains  a  larger 
proportion  of  fibrine  than  usual,  a  state  to 
which  the  more  rapid  deposition  of  the  glo- 
bules, and  the  formation  of  the  inflammatory 
crust,  which  is  its  consequence,  may  be  at- 
tributed. 

Thus  far  we  have  only  spoken  of  the  blood 
in  a  general  manner,  and  without  respect  to 
the  part  of  the  system  in  which  this  fluid  is 
examined ;  it  is,  however,  very  far  from  being 
identical  in  every  part,  and  there  are  wide 


differences  between  the  physical  and  physio- 
logical properties  of  arterial  and  of  venous 
blood. 

The  blood  which  is  tending  to  the  several 
parts  of  the  body  is  in  the  first  place  of  a 
bright  vermilion  red  colour  (arterial,  blood); 
whilst  that  which  has  already  passed  through 
the  different  tissues,  and  is  on  its  way  back 
from  them,  is  of  a  dusky  or  blackish  red  of 
various  degrees  of  intensity  (venous  blood). 
Arterial  blood  also  coagulates  more  quickly 
than  venous  blood,  and,  from  the  researches 
of  Dr.  John  Davy,  appears  to  have  rather  a 
less  capacity  for  caloric,*  and  a  somewhat  in- 
ferior specific  gravity  (1,049:  1,051);  we  are, 
however,  led  to  think  that  in  the  normal  state 
the  contrary  of  the  latter  proposition  will  be 
found  to  obtain,  for  Messrs.  Prevost  and  Du- 
mas have  shown  that  in  this  case  arterial  blood 
contains  a  larger  proportion  of  globules  than 
venous  blood. f 

When  the  physiological  action  of  arterial 
and  of  venous  blood  is  investigated,  still  more 
striking  differences  are  discovered ;  the  first 
maintains  vital  excitation  in  the  economy,  and 
the  second  is  insufficient  to  support  life. 
Physiologists  have  even  gone  so  far  as  to 
regard  the  influence  of  the  venous  blood  upon 
the  brain  as  deleterious ;  J  but  more  recent 
experiments  show  that  though  inadequate  to 
keep  up  life,  it  is  far  from  being  a  poison ; 
on  the  contrary,  it  rather  tends  to  prolong 
existence,  for  frogs  whose  vascular  system  is 
filled  with  this  liquid  die  less  speedily  than 
those  placed  under  similar  circumstances,  but 
which  have  lost  almost  the  whole  of  their  blood 
by  haemorrhage.§ 

The  blood  thus  modified  by  the  influence 
of  the  organs  it  permeates,  is  still  susceptible 
of  resuming  its  primaiy  colour,  and  of  ac- 
quiring at  the  same  time  its  vivifying  pro- 
perties :  it  is  enough  to  expose  it  to  the  con- 
tact of  oxygen,  to  give  it  back  all  its  peculiar 
qualities.  We  find,  in  fact,  that  if  venous 
blood  be  agitated  with  atmospheric  air, 
or  better  still  with  oxygen  gas,  it  speedily 
assumes  the  vermilion  tint  that  characterizes 
arterial  blood,  and  if  the  air  thus  employed 
be  afterwards  analysed,  a  certain  quantity  of 
oxygen  will  be  found  to  have  disappeared,  and 
its  place  to  be  occupied  with  a  corresponding 
measure  of  carbonic  acid.  Now  that  which 
happens  here  under  the  influence  of  mere 
chemical  affinity,  also  takes  place  in  the  ani- 
mal economy,  and  it  is  even  thus  that  venous 
blood  in  being  exposed  to  the  contact  of 
atmospheric  air  in  the  respiratory  apparatus, 
whatever  its  nature,  changes  into  arterial  blood 
and  again  becomes  fit  to  minister  to  life.  (See 
RESPIRATION.)  On  the  other  hand,  if  ver- 
milion-coloured blood  be  subjected  to  the 
action  of  carbonic  acid,  it  speedily  acquires  a 


*  Philos.  Trans.  1815. 

t  Ann.  de  Chimie,  t.  xxiii.  p.  67. 

j  Bichat,  sur  la  Vie  et  la  Mort.  See  also  the 
article  ASPHYXIA. 

§  M.  Edwards,  Influence  des  Agens  Physiques 
»nr  la  Vie,  translated  by  Dr.  Hodgkin. 


BLOOD,  MORBID  CONDITIONS  OF  THE 


deep  or  blackish  hue,  and  then  resembles 
venous  blood  in  its  appearance  and  pro- 
perties. 

It  now  became  a  question  of  the  very 
highest  importance  in  the  theory  of  respiration 
to  ascertain  whether  the  oxygen  acting  upon 
the  blood  in  the  manner  specified,  produced 
the  carbonic  acid  disengaged,  by  combining 
directly  with  carbon  supplied  by  the  colouring 
matter  or  some  other  element  of  the  blood, 
or  whether  the  oxygen  was  simply  dis- 
solved by  the  blood  and  in  dissolving  ex- 
pelled the  carbonic  acid  which  existed  in  it 
ready  formed. 

Various  experiments  satisfy  us  that  venous 
blood  contains  carbonic  acid  already  formed. 
My  brother,  Dr.  W.  F.  Edwards,  has  shown 
that  those  animals  which  possess  the  greatest 
powers  of  resisting  asphyxia  continue  for  a 
long  time  to  disengage  carbonic  acid  when 
kept  in  vessels  filled  with  pure  azote  or  hy- 
drogen, circumstances  under  which  it  is  im- 
possible that  the  carbonic  acid  evolved  can 
proceed  from  the  direct  combination  of  in- 
spired oxygen  with  the  carbon  of  the  blood. 

By  placing  venous  blood  under  the  receiver 
of  an  air-pump,  several  inquirers  had  indeed 
already  found  that  bubbles  of  carbonic  acid 
gas  were  disengaged  from  it,  when  the  pres- 
sure of  the  atmosphere  was  withdrawn.  This 
fact,  first  observed  by  Vogel,*  has  been  verified 
by  Messrs.  Brande,  Bauer,f  and  others.  The 
quantity  of  carbonic  acid  disengaged  in  this 
way,  however,  is  very  small,  and  altogether 
inadequate  to  explain  the  phenomena  accom- 
panying respiration ;  but  if,  after  having  freed 
a  quantity  of  blood  as  completely  as  possible 
from  its  carbonic  acid  by  means  of  the  air- 
pump,  it  be  agitated  with  hydrogen  or  any 
other  gas,  this  will  be  absorbed,  and  a  fresh 
and  corresponding  disengagement  of  carbonic 
acid  will  be  determined .\  On  the  other  hand 
there  is  an  experiment  of  Girtanner,  mentioned 
by  Hassenfratz,§  which  goes  to  prove  that 
arterial  blood  contains  a  portion  of  free  oxygen 
io  its  constitution  ;  but  this  conclusion  appears 
to  require  confirmation. 

The  bright  vermilion  or  dusky  red  colour  of 
the  blood,  however,  does  not  depend  solely 
on  the  nature  of  the  gas  it  holds  in  solution, 
or  with  which  its  colouring  matter  is  in  com- 
bination. The  recent  experiments  of  Dr. 
Hoffmann  shew  that  the  presence  of  the  saline 
matters  it  contains  is  necessary  to  the  phe- 
nomena in  question.  Blood  freed  from  these 
saline  ingredients  is  black,  and  cannot  be 
brought  to  the  vermilion  red  tint  as  usual  by 
the  action  of  oxygen.  The  same  physiologist 
also  ascertained  that  the  presence  of  an  over- 
dose of  saline  matter  in  blood  charged  with 
carbonic  acid,  equally  prevented  the  ordinary 
action  of  oxygen  in  changing  its  colour. 

The  blood  does  not  invariably  exhibit  the 
properties  and  the  mode  of  composition  which 

*  Schweigger's  Journal,  Bd.  xi. 

t   Home,  Croonian  Lecture,  Philos.  Trans.  1818. 
J   Hoffmann,  Lond.  Med.  Journ.   May,  1828. 

*  -Van.  de  Chimie,  liere  Serie,  t.  ix. 


415 

we  have  just  ascribed  to  it  in  the  normal  state. 
There  was  a  time  when  physicians  ascribed 
the  greater  number  of  internal  maladies  to 
alterations  of  this  fluid  ;  the  general  errone- 
ousness  of  this  opinion,  however,  was  at 
length  detected,  and  at  the  present  day  patho- 
logists  have  probably  fallen  into  the  opposite 
extreme,  namely,  that  of  neglecting  the  study 
of  the  changes  which  the  blood  does  actually 
undergo,  although  these  are  sufficiently  striking 
in  many  cases,  and  undoubtedly  exert  an  im- 
mense influence  upon  the  animal  economy. 
A  careful  examination  of  their  kinds  and  effects 
were  undoubtedly  fraught  with  results  of  equal 
importance  in  a  medical  as  in  a  physiological 
point  of  view. 

(H.Milne  Edwards.) 

BLOOD,  MORBID  CONDITIONS  OF 
THE. — The  nature  and  properties  of  blood  in 
its  normal  condition  having  been  considered  in 
the  foregoing  article,  we  proceed  to  notice  those 
changes  to  which  it  is  liable  in  a  state  of 
disease. 

That  a  fluid  which  is  destined  to  receive  and 
convey  materials  for  the  formation,  increase,  and 
repair  of  every  structure  in  the  animal  frame, 
which  carries  away  whatever  is  useless,  and  is 
brought  into  perpetual  contact  with  the  external 
atmosphere,  should  itself  be  subject  to  morbid 
alterations,  is  a  notion  so  natural,  so  entirely  in 
accordance  with  what  might  a  priori  be  ex- 
pected, that,  independently  of  all  reasoning,  and 
antecedently  to  all  proof,  it  has  existed  in  the 
common  belief  of  every  age  and  of  every 
nation. 

To  preserve  a  healthy  state  of  the  blood  has 
accordingly  ever  been  considered  an  object  of 
primary  importance.  The  greatest  pains  have 
been  taken  to  maintain  its  purity,  as  well  in  the 
individual  as  the  species ;  not  only  in  man,  but 
in  all  those  animals  which  he  has  domesticated 
for  his  use;  and  there  is  no  belief  more  generally 
received  than  that  which  attributes  the  origin 
of  many  of  the  cutaneous  eruptions,  and  of 
most  of  the  cachectic  diseases,  to  the  degene- 
racy and  poverty  of  this  vital  stream. 

When  from  this  general  and  popular  notion 
we  advance  to  the  more  especial  assumption 
that  the  origin  of  all  diseases  is  to  be  found  in 
the  blood  and  other  fluids ;  when  we  classify 
these  into  hot  and  cold,  moist  and  dry,  or  into 
blood,  bile,  black  bile  and  phlegm,  and  attribute 
morbid  changes  and  even  natural  dispositions  to 
the  prevalence  of  one  or  other  of  these  supposed 
humours,  we  quit  the  belief  of  the  people  to 
follow  theories  far  less  tenable,  invented  at  a 
period  when  authoritative  assertions  had  the 
weight  of  proof,  and  when  the  dogmata  of  a 
philosopher  were  preferred  to  facts  plainly  re- 
corded in  the  book  of  nature. 

It  would  be  out  of  place  here  to  enter  into  a 
discussion  of  the  merits  of  the  humoral  pa- 
thology as  compared  with  the  various  doctrines 
which  have  supplanted  it,  and  to  which  it  is 
not  unlikely  that  in  an  improved  form  it  may 
again  succeed. 

Under  the  triple  relation  of  vital  phenomena, 
intimate  structure,  and  chemical  composition,  as 


416 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


Andral*  justly  remarks,  we  can  draw  no  definite 
line  of  demarcation  between  the  blood  and  the 
solids.  Physiologically  speaking,  we  cannot 
conceive  that  of  these  two  facts  which  form  a 
single  whole,  the  one  can  be  modified  without 
affecting  the  other.  Since  the  blood  nourishes 
the  solids,  they  must  necessarily  be  influenced 
by  its  state ;  and  since  the  solids  furnish  ma- 
terials from  which  the  blood  is  formed,  and 
abstract  materials  by  which  it  is  decomposed, 
any  alteration  in  the  nature  or  quantity  of  these 
must  necessarily  have  its  influence  on  this  fluid. 
Suffice  it  then  to  observe  that  the  further  we 
extend  our  knowledge  of  pathology,  the  less 
shall  we  feel  inclined  to  admit  the  exclusive 
claims  either  of  fluidism  or  solidism,  and  the 
more  shall  we  strengthen  our  belief  that  the 
animal  structure  is  composed  of  parts,  every 
one  of  which  may  not  only  partake  of  disease, 
but,  under  certain  circumstances,  become  its 
cause. 

Quitting,  therefore,  all  unprofitable  specu- 
lations on  this  subject,  we  proceed  at  once  to  a 
detail  of  facts,  and  to  such  observations  in  elu- 
cidation of  them  as  occasion  may  suggest. 

Blood  may  be  excessive  in  quantity,  thus 
constituting  a  state  of  plethora  in  which  the 
circulating  system  is  supplied  more  abundantly 
than  is  needed  for  the  due  performance  of  the 
functions  of  nutrition  and  secretion.  A  ten- 
dency to  accumulation  in  the  capillaries  and  in 
the  different  internal  organs  is  induced,  and  con- 
gestion with  its  consequences,  or  actual  rupture 
of  the  bloodvessels,  is  the  result.  Drowsiness, 
vertigo,  headache,  epilepsy,  apoplexy,  mark  this 
state  as  existing  in  the  head ;  dyspnoea,  and  a 
livid  or  purple  hue  of  the  skin,  as  affecting  the 
lungs;  palpitation  and  irregular  action  wi'th 
syncope  mark  the  ineffectual  struggle  of  the 
heart  to  propel  its  contents.  Haemorrhages  from 
the  mucous  membranes  of  the  nose,  the  lungs, 
or  the  intestines,  are  often  the  consequence  of 
congestion  in  the  vessels  which  ramify  on  their 
surface;  while  indigestion,  torpor,  and  biliary 
redundancy,  are  connected  with  a  plethoric 
condition  of  the  abdominal  viscera.  Although 
the  existence  of  such  a  state,  as  deducible  from 
the  symptoms  just  enumerated,  as  well  as  from 
the  effect  which  depletion  has  in  removing  them, 
admits  of  no  doubt,  it  has,  nevertheless,  not 
been  made  the  subject  of  direct  proof.  The 
proportion  which  the  circulating  blood,  even  in 
a  healthy  animal,  bears  to  its  total  weight  has 
not  been,  and,  perhaps,  cannot  be  ascertained 
with  precision.  Haller  collects  together  many 
authorities  at  variance  with  each  other  on  this 
point,  and  at  length  comes  to  the  conclusion, 
"  Neque  dissimulandum  est,  obiter  haec  et  vage 
definiri.  Infinita  enim  procul  dubio  in  ratione 
sanguinis  ad  reliquam  corporis  molem  varietas 
est."f 

Fat  men  and  animals  have  less  blood  than 
lean,  old  than  young;  and  yet  plethora  is 
oftener  found  in  the  former  than  the  latter, 
obviously  on  account  of  the  mechanical  ina- 


*  Precis  d'Anatomie  Pathologique,  p.  526. 
t  Elemcnta  Physiologiae,  torn.  ii.  p.  5. 


pediment  which  the  encumbered  tissue  or  the 
rigid  fibre  offers  to  the  circulation. 

The  state  of  ansemia,  or  a  deficiency  in  the 
quantity  of  circulating  blood,  whether  induced 
by  natural  or  artificial  causes,  is  no  less  detri- 
mental to  health  than  its  excess.  Its  symptoms 
are  general  pallor,  weak  circulation,  languor, 
syncope  with  palpitations,  oppressed  respi- 
ration, flatulency,  general  oedema,  and,  in 
extreme  cases,  effusion  into  all  the  serous 
cavities. 

Neither  plethora  nor  anaemia  necessarily 
imply,  though  they  are  generally  complicated 
with  some  morbid  change  in  the  blood  itself. 
We  therefore  pass  them  over  with  this  slight 
notice,  referring  for  further  information  to  the 
excellent  observations  of  Andral,  in  his  work  on 
Pathological  Anatomy. 

The  circulating  blood  consists  essentially  of 
a  homogeneous  fluid  and  red  particles,  and  the 
former,  when  removed  from  the  body  or  from 
the  circulation,  separates  into  a  fluid  and  a  solid 
portion.  The  solid,  when  washed  and  freed 
from  the  serum  and  red  particles  which  are 
mechanically  entangled  in  its  substance,  consti- 
tutes the  proximate  animal  principle  called 
fibrine.  The  fluid  contains  water,  albumen, 
oil,  animal  extractive,  and  salts,  alkaline,  earthy, 
and  metallic. 

With  the  exception  of  the  oil  and  fatty 
matter,  which,  in  a  healthy  state  of  the  blood, 
do  not  amount  to  four  parts  in  a  thousand,  its 
constituents  are  all  heavier  than  water,  and 
something  is  to  be  learned  by  ascertaining 
its  specific  gravity.  In  the  information  thus 
gained,  however,  we  are  limited  to  the  al- 
ternative, either  that  some  one  or  more  of  these 
constituents  is  in  a  state  of  excess  or  of  de- 
ficiency, the  proportion  of  water  remaining 
normal,  or  that  the  water  itself  is  either  su- 
perabundant or  deficient. 

The  specific  gravity  of  healthy  blood  has 
been  variously  stated  by  different  authors. 
Haller  makes  it  on  the  average  1,052 ;  Blu- 
menbach,  1,054;  Berzelius,  from  1,0527  to 
1.057;  Denis,  1,059;  but  none  of  these  au- 
thors note  the  temperature  at  which  it  was 
taken,  although,  from  their  manner  of  ascertain- 
ing it,  there  must  have  been  considerable 
variety  in  this  respect.  By  experiments  which 
I  have  often  repeated  with  an  accurate  specific 
gravity  bottle  holding  1,000  grains  of  distilled 
water,  I  find  that  with  that  fluid  four  degrees 
of  Fahrenheit's  thermometer  corresponds  with 
a  difference  of  -001  of  specific  weight,  water 
being  1,000.  Consequently,  if  one  author 
states  the  specific  gravity  of  blood  at  its  circu- 
lating temperature  98°  Fahrenheit,  while  an- 
other states  it  at  60e  Fahrenheit,  the  usual 
standard,  the  former  will  make  it  -0095  lighter 
than  the  latter. 

The  heaviest  blood  of  which  I  find  a  record 
among  my  own  observations  was  that  of  a  man 
suffering  under  diabetes  mellitus.  At  a  tempe- 
rature of  87°  Fahrenheit  it  was  of  specific  gra- 
vity 1-0615,  while  that  of  the  serum  was  under 
the  average  standard  of  health,  namely,  1-027 
at  60°  Fahrenheit,  and  of  the  medium  propor- 
tion t-0  the  crassamentum,  being,  after  twelve 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


417 


hours'  rest,  as  1000  to  1323.     The  specific  gra- 
vity of  the  crassamentum  was  1-088. 

The  lightest  blood  which  I  have  met  with 
was  of  specific  gravity  1-031,  at  90°  Fahren- 
heit. It  was  taken  from  the  arm  of  a  female, 
aged  22,  who  was  bled  on  account  of  headach, 
and  had  a  full  pulse  of  1 17. 

The  red  particles  being  the  heaviest  of  all 
the  constituents  of  the  blood,  their  relative 
quantity  must  greatly  affect  its  specific  gravity; 
and  as  Messrs.  Prevost  and  Dumas  have  shewn 
that  they  bear  a  general  proportion  to  the  de- 
gree of  animal  heat,  we  might  reasonably  sup- 
pose that,  cateris  paribus,  the  heaviest  blood 
would  be  found  in  those  diseases  which  are 
marked  by  high  action  and  increased  tempera- 
ment. In  a  fluid  so  complicated,  however,  in 
which  every  constituent  is  liable  to  such  variety 
in  quantity,  it  is  difficult  to  estimate  the  precise 
influence  of  each.  I  am  not  aware  that  any 
experiments  have  been  made  on  this  subject. 

Blood  diminishes  in  specific  gravity  in  pro- 
portion to  its  frequent  abstraction,  for  the  red 
particles  and  the'  fibrine  are  reproduced  with 
more  difficulty  than  the  serum  or  the  salts.  The 
serum  also  becomes  lighter  from  a  gradual  di- 
minution of  its  solid  contents.  A  recent  paper 
by  Mr.  Andrews,  in  the  fifteenth  volume  of  the 
Medical  Gazette,  p.  592,  proves  these  facts  very 
satisfactorily  by  experiments  made  on  calves. 
They  have,  however,  been  long  known. 

The  specific  gravity  of  morbid  blood,  says 
Thackrah,  differs  little  from  that  of  healthy 
blood ;  but  this  observation  is  only  true  of  an 
average  deduced  from  numerous  specimens  of 
blood  examined  under  different  forms  of  dis- 
ease. It  would  be  equally  true,  perhaps, 
according  to  the  same  mode  of  obtaining  a 
result,  were  we  to  affirm  that  the  temperature 
of  the  body  or  the  state  of  the  pulse  differed 
little  in  health  and  disease,  since  there  might 
be  as  many  instances  of  deficiency  as  of  ex- 
cess in  heat  or  action.  The  assertion  is  not 
applicable  to  particular  cases,  and  is,  therefore, 
without  value.  Blood  may  be  morbid  from 
an  undue  proportion  of  any  of  its  constituents, 
and  it  will  be  heavier  or  lighter  than  healthy 
blood  according  to  the  preponderance  of  the 
heavier  or  lighter  principles.  Where  the  spe- 
cific weight  is  increased,  it  is  generally  owing 
to  a  deficiency  in  the  proportion  of  water,  as  in 
the  blood  of  cholera  and  diabetes ;  sometimes 
to  an  increase  of  fibrine  and  red  particles,  as  in 
plethora,  gout,  and  rheumatism. 

The  following  table,  containing  the  specific 
gravities  of  blood  under  several  forms  of  dis- 
ease, is  compiled  from  a  few  cases  of  my  own 
which  were  recorded  for  another  purpose. 
Though  short,  it  will  be  sufficient  to  shew  that 
considerable  variety  occurs,  and  may  collaterally 
suggest  that  in  determining  the  propriety  of  de- 
pletion, it  may  in  some  cases  become  impor- 
tant thus  to  ascertain  the  proportion  of  solid 
matter  existing  in  the  circulation.  A  specific 
gravity  bottle,  holding  1000  grains  of  distilled 
water,  was  employed  in  all  the  experiments,  so 
that  the  proportion  of  serum  to  clot  was  not 
influenced  by  variation  in  the  shape  or  material 
of  the  receiver. 

VOL.  I. 


ion  o 
o  clo 


8888 

^  ^  _  ,_ 


§0 
o 
oo 


0000 
oooo 
oooo 


55 


f*-*^-T- 
COCO<N<N<NCO<N<N<M.<N(N(N(N<M<N 

ooooooooooooooo 


En     R 


'r-  iT-'--'— 

rfO^tl'^fJv54OT1<Ttl^f^<O"!fT^'lO'^f 

ooooooooooooooo 


2  E 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


418 


The  specific  gravity  of  morbid  serum  has 
been  much  oftener  ascertained  than  that  of 
morbid  blood,  and  it  leads  to  more  precise 
information.  The  normal  proportion  of  salts 
does  not  raise  the  specific  gravity  of  serum 
above  that  of  distilled  water  more  than  five  parts 
in  1000.*  The  excess  beyond  this  increase  is 
owing  to  the  presence  of  albumen.  The  quan- 
tity of  other  animal  matter  is  too  small  to  be 
worth  taking  into  the  account.  Hence  the  spe- 
cific gravity  of  serum  indicates  with  tolerable 
accuracy  the  quantity  of  albumen  it  contains. 

In  some  states  of  disease,  where  albumen  is 
rapidly  carried  out  of  the  system,  as  in  dis- 
eased kidneys,  in  dropsies,  and  in  profuse 
haemorrhages,  the  specific  gravity  of  serum  has 
been  observed  as  low  as  l'013,f  whilst  in  other 
states,  where  water  and  even  salts  are  removed, 
as  in  cholera,  it  is  found  as  high  as  1-041  .J 

Neither  the  specific  gravity  of  fibrine  nor  of 
red  particles  has  been  hitherto  stated  by  authors. 
The  former,  by  immersion  in  solution  of  salt,  I 
find  to  be  1-079  at  60°  Fahrenheit.  Some  of 
the  latter  will  fall  to  the  bottom  of  a  solution 
of  specific  gravity  1-129,  and  when  agitated 
with  a  solution  of  even  specific  gravity  1-207, 
which  is  the  point  of  saturation,  will  not  rise 
to  the  top;  but  the  experiment  is  not  con- 
clusive, for  the  red  particles  certainly  undergo 
some  change  by  the  addition  of  salt  in  solution. 

The  temperature  of  the  blood  is  materially 
influenced  by  disease.  In  fevers  it  is  generally 
though  »ot  always  above  the  healthy  standard. 
In  the  cold  stage  of  an  intermittent  the  tempe- 
rature of  the  skin  has,  according  to  Dr.  Wilson 
Philip,  been  observed  as  low  as  74°  Fahren- 
heit, while  in  its  hot  stage  it  has  increased  to 
105°.  A  corresponding  diminution  or  increase 
in  the  temperature  of  the  blood  in  all  probability 
occurred  in  these  cases.  Haller  cites  authorities 
to  prove  that  in  pleurisy  and  yellow  fever  the 
tempeiature  of  the  blood  has  been  known  to  rise 
to  102°  and  104°,  in  intermittent  fever  to  106° 
and  108°,  and  in  continued  fever  to  109°.  Mor- 
gagni  devotes  several  pages  to  the  history  of  a 
woman,  as  related  in  the  journal  of  a  cotempo- 
rary,  Media  Via,  whose  blood  flowed  in  an 
icy  cold  state  from  the  arm.  The  serum  of 
this  blood  was  in  small  proportion  and  of  a 
yellow  colour;  the  crassamentum  black  and 
viscid.  This  person  seems  to  have  undergone 
repeated  venesection.  Thackrah  witnessed  a 
similar  phenomenon. 

Whatever  theory  may  be  adopted  respecting 
the  generation  of  animal  heat,  it  is  a  fact  which  is 
generally  admitted,  that  it  is  effected  through 
the  medium  of  the  blood,  that  it  is,  catcris 
puribus,  increased  in  proportion  to  the  velocity, 
freedom,  and  force  of  the  circulation,  and  that  it 
is  mainly  dependent  for  its  development  upon 
the  presence  of  the  red  particles.  Wherever 
these  are  deficient,  either  from  natural  disease 
or  artificial  depletion,  animal  heat  is  deficient 
likewise.  Chlorotic  females  and  those  who  are 
subject  to  habitual  losses  of  blood  usually 

*  Med.-Chir.  Trans,  vol.  xvi.  part  i.  p.  57. 

f    Bright'g  Reports,  vol.  i.  p.  85. 

$  O'Shatighnessy's  Report  on  Cholera,  p.  29. 


suffer  from  coldness  of  the  extremities.  The 
phenomenon  of  fainting  is  always  accompanied 
by  diminished  temperature;  and  whenever  we 
cut  off  the  supply  of  blood  from  a  limb,  it  loses 
its  natural  warmth  as  an  immediate  conse- 
quence. Plethoric  subjects,  on  the  contrary, 
provided  their  circulation  be  unimpeded  at  its 
capillary  extremities,  or  in  the  process  of  the 
pulmonary  ventilation,  are  liable  to  preter- 
natural heat  of  the  surface  and  profuse  perspi- 
ration. As  an  actual  diminution  or  increase  in 
the  quantity  of  the  red  particles  produces  a 
corresponding  increase  or  diminution  of  animal 
heat,  notwithstanding  the  natural  change  of 
venous  to  arterial  blood,  so  likewise  any  cause 
which  impedes  that  change,  although  the  red 
particles  be  not  deficient  in  quantity ,will  produce 
a  like  effect.  Thus,  in  diseases  of  the  heart,  in 
pulmonary  obstructions,  especially  of  a  spas- 
modic character,  in  the  cold  fit  of  ague,  and  in 
Asiatic  cholera,  there  is  a  diminution  of  the 
natural  warmth,  although  there  is  no  reason  to 
suppose  that  the  red  particles  are  actually  less 
abundant  than  in  health. 

Fibrine  may  undergo  alterations  in  quality 
during  disease.  In  the  healthy  state  it  is  com- 
posed of  definite  quantities  of  oxygen,  hydrogen, 
azote,  and  carbon ;  and  it  is  quite  possible  that 
some  variety  in  the  proportion  of  these  consti- 
tuents may  give  rise  in  disease  to  morbid  states 
of  that  principle.  Huxham  observes  that  in 
malignant  petechial  fevers  the  crasis  is  so 
broken  as  to  deposit  a  sooty  powder  at  the 
bottom  of  the  vessel,  the  upper  part  being  either 
a  livid  gore,  or  a  dark  green,  and  exceedingly 
soft  jelly.  De  Haen  saw  the  blood  in  a  dis- 
solved state,  and  in  the  plague  the  blood  is 
said  not  to  coagulate. 

In  some  persons  there  exists  a  state  of  con- 
stitution, bordering  no  doubt  upon  passive  hce- 
morrhagic  disease,  in  which  the  blood  is  ob- 
served either  to  coagulate  very  imperfectly  or 
not  at  all.  Alarming  haemorrhages  from  the 
slightest  wounds  are  the  consequence  of  such  a 
diathesis,  and  the  most  powerful  styptics  will 
not  always  succeed  in  preventing  their  fatal 
termination.  Dr.  Wardrop,  in  a  small  work 
just  published,  has  collected  together  several 
interesting  cases  of  this  kind,  and  from  some  of 
these  it  is  demonstrated  that  such  a  condition 
may  exist  in  many  members  of  the  same  family, 
and  even  sometimes  become  hereditary. 

In  the  dead  body  blood  is  sometimes  found 
in  a  liquid  state,  resembling  water,  holding  in 
suspension  a  red,  brown,  or  black  colouring 
matter.  In  this  case,  according  to  M.  Andral, 
it  has  been  demonstrated  chemically  that  it 
still  contains  fibrine,  but  altered  in  its  character, 
so  as  to  be  no  longer  coagulable.  This  dis- 
solved state  of  blood  observable  after  death  is 
probably  the  same  as  that  which  exists  in  sea- 
scurvy,  in  putrid  and  typhous  fevers,  and  in 
the  latter  stages  of  fatally  terminating  diseases 
characterized  by  defective  nervous  energy.  It 
is  matter  of  more  common  observation,  how- 
ever, that  fibrine  alters  materially  in  its  relative 
quantity.  We  often  find  that  the  clot  is  large 
in  proportion  to  the  serum,  which  may  indeed 
arise  from  its  being  loose  and  defective  in  con- 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


tractflity,  so  as  to  contain  a  large  portion  of 
fluid,  or  from  its  holding  entangled  among  its 
meshes  an  unusual  number  of  red  particles ; 
but  it  will  often  also  arise  from  there  being  a 
more  than  ordinary  quantity  of  fibrine  present, 
in  which  case  it  will  be  firm  and  contractile  as 
well  as  voluminous.  Blood  thus  circumstanced 
is  said  to  be  rich  and  thick,  and  is  generally 
met  with  in  those  whose  complaints  are  con- 
nected with  a  plethoric  habit. 

A  deficiency  in  the  proportion  of  fibrine  is 
likewise  not  unfrequent  among  those  who  suffer 
from  complaints  of  debility,  or  who  have  lost 
much  blood  by  natural  or  artificial  depletions. 
In  this  case  the  clot  is  small,  and  has  but  little 
contractile  power. 

It  is,  I  conceive,  a  possible  case,  that  the 
fibrine  may  separate  imperfectly  or  not  at  all, 
in  consequence  of  an  augmented  proportion  of 
salts,  which  out  of  the  body  we  know  to  be 
capable  of  suspending  coagulation  altogether. 
The  continued  use  of  alkaline  remedies  will 
probably  tend  to  produce  a  like  effect. 

Fibrine  coagulates  the  more  speedily  in 
porportion  as  the  circulating  and  nervous  sys- 
tems become  more  feeble.  The  experiment 
has  been  repeatedly  made  with  animals  that 
are  killed  by  bleeding,  and  the  last  por- 
tions of  blood  invariably  coagulate  soonest. 
*  The  principle  of  the  blood's  speedy  con- 
cretion in  debility  is  important  in  a  curative 
point  of  view.  The  first  natural  check  to  hae- 
morrhage is  known  to  be  the  formation  of  a  clot 
on  the  mouth  of  the  vessel.  If  the  longer  the 
haemorrhage  the  less  had  been  the  disposition  to 
form  such  a  clot,  the  wounded  on  the  field  of 
battle,  and  those  injured  by  common  accidents, 
who  cannot  promptly  procure  the  aid  of  a 
surgeon,  must  inevitably  have  perished."* 

One  of  the  most  remarkable  and  frequent  de- 
viations from  the  normal  condition  of  blood 
removed  from  the  body  by  venesection,  is  the 
occurrence  of  the  buffy  coat,  which  is  a  layer  of 
fibrine  occupying  the  surface  of  the  crassa- 
mentum.  The  blood,  whilst  circulating  within 
its  vessels,  consists,  as  I  have  already  remarked, 
of  a  fluid  which  I  have  elsewhere  ventured  to 
call  liquor  sang  u  in  is,  and  of  insoluble  red  par- 
ticles. These  being  in  constant  motion  are 
uniformly  diffused  throughout  this  liquor;  but 
their  specific  gravity  being  much  greater  than 
that  of  the  medium  in  which  they  are  sus- 
pended, they  have  a  tendency  to  gravitate  when- 
ever that  motion  ceases.  In  healthy  blood  the 
fibrine  coagulates  so  quickly  that  the  red  par- 
ticles have  not  time  to  subside,  so  as  to  leave 
any  portion  of  the  liquor  entirely  free  from 
them.  By  protracted  fluidity  this  result  is 
effected ;  the  red  particles  do  then  gravitate  to  a 
greater  or  less  depth  before  the  liquor  separates 
into  two  parts.  A  general  coagulation  of  the 
fibrine  at  length  occurs,  and  a  clot  is  formed. 
That  part  of  it  through  which  the  red  particles 
had  fallen  becomes  a  layer  of  fibrine  free  from 
colour,  and  merely  having  some  serum  mecha- 
nically retained  in  its  meshes,  while  the  sub- 
jacent portion  is  of  intense  depth  of  shade, 

*  Thaqkrah,  p.  188. 


419 

especially  at  the  bottom,  and  of  less  than  ordi- 
nary cohesion.  In  extreme  cases,  such  an 
abundance  of  red  particles  reaches  the  bottom 
of  the  vessel  that  they  are  there  found  in  a 
state  of  fluidity.  The  buffed  layer  sometimes 
assumes  a  cupped  form,  which  is  clearly  owing 
to  unequal  contraction.  The  upper  surface 
being  freer  from  intervening  red  particles,  con- 
tracts more  powerfully  than  the  under,  and  a 
concavity  of  the  surface  is  the  necessary  con- 
sequence. Where,  however,  the  contraction  is 
weaker,  the  weight  of  the  subjacent  red  clot, 
which  is  one  and  the  same  mass  with  the  upper 
colourless  portion,  weighs  this  down,  and  keeps 
it  in  a  horizontal  position. 

The  crassamentum  of  arterial  as  well  as  of 
venous  blood  has  frequently  been  observed  to 
exhibit  a  buffy  coat.  It  is  rarely  seen  in  blood 
extracted  by  cupping-glasses,  and  never  in  that 
pressed  from  leeches.  It  occurs  in  the  lower 
animals,  and  is  observed  as  frequently  in  the 
horse  as  in  the  human  subject ;  indeed,  from 
the  quantity  of  blood  usually  drawn  from  that 
animal,  it  is  still  more  strikingly  apparent,  being 
occasionally  several  inches  thick.  It  has  been 
denied  that  the  cupped  appearance  is  ever  met 
with  in  the  blood  of  the  horse ;  but  if  this  be 
received  into  a  sufficiently  small  vessel,  it  will 
be  in  some  instances  as  complete  as  in  blood 
taken  from  the  human  subject.  There  are  va- 
rieties in  the  appearance  of  the  buffed  coat 
which  it  is  worth  while  to  notice.  It  is  gene- 
rally of  a  firm  uniform  consistence,  and  of  a 
light  yellow  or  buff  colour,  whence  its  name. 
Sometimes,  however,  it  is  of  a  more  spongy 
texture,  and  of  a  white  or  bluish,  and  more 
transparent  hue.  Two  layers  of  buff  are  occa- 
sionally seen ;  the  upper  soft  or  friable,  the  in- 
ferior more  compact.  "  There  is  a  difference," 
says  Sir  Gilbert  Blane,  "  in  the  appearance  of 
the  blood  when  sizy,  perhaps  not  sufficiently 
insisted  on  by  practical  writers;  for  though 
there  should  even  be  a  very  thick  buff,  yet  if 
the  surface  is  flat,  and  the  crassamentum  tender, 
no  great  inflammation  is  indicated  in  com- 
parison of  that  state  of  the  blood  wherein  the 
surface  is  cupped,  the  crassamentum  contracted 
so  as  to  form  the  appearance  of  a  large  pro- 
portion of  serum,  and  where  it  feels  firm  and 
tenacious,  though  perhaps  but  thinly  covered 
with  buff."* 

From  the  examination  of  several  specimens! 
of  buffed  blood,  I  was  at  one  time  led  to  be- 
lieve that  its  serum  was  always  deficient  in 
its  due  proportion  of  albumen ;  but  this  I  have 
Since  found  not  to  be  the  case,  having  met 
with  blood  thickly  buffed,  the  serum  of  which 
at  60°  Fahr.  had  a  specific  gravity  of  only 
1*024,  and  with  another  specimen  where  the 
layer  of  fibrine  was  equally  thick,  of  which, 
at  the  same  temperature,  the  serum  had  a  spe- 
cific gravity  of  1-040.  Dr.  John  Davy  examined 
the  specific  gravity  of  buffed  blood  in  eleven 
cases.  In  five  of  them  in  which  the  buffy 
coat  was  slight,  the  specific  gravities  were  T047, 
1-051,  1-054,  1-055,  1-054;  in  five  others  in 
which  the  buffy  coat  was  moderately  thick,  the 

*  Blane  on  the  Diseases  of  Seamen,  note  to  page 

2  E  2 


420 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


specific  gravities  were  1-044,  1-038,  1-052, 
1-056;  and  in  one  instance  in  which  it  was 
thick,  the  specific  gravity  was  1'057.  Taking 
the  mean  gravity  of  healthy  blood  at  1-044, 
which  I  believe  will  be  found  correct,  it  would 
thus  appear  that  the  buffy  coat  is  more  frequent 
in  blood  above  than  below  the  mean  weight ; 
but  it  is  also  clear  that  it  may  exist  in  either 
state,  and  the  number  of  experiments  is  not 
sufficient  to  lead  to  any  conclusive  result. 

De  Haen,  Hewson,  and  others  have  met  with 
cavities  in  the  crassamentum  of  buffed  blood 
containing  clear  fluid  (liquor  sanguinis),  which, 
on  being  evacuated  several  hours  afterwards, 
separated  into  fibrine  and  serum.  This  fact  is 
analogous  to  that  of  fluid  blood  having  been 
found  by  Hewson  in  the  heart  of  a  dog  thirteen 
hours  after  death,  which  blood,  on  being  re- 
moved, coagulated  soon  after  exposure  to  the 
air.  A  similar  coagulation  will  occasionally 
take  place  in  fluid  blood  taken  from  the  human 
heart  several  hours  after  the  extinction  of  life. 

The  remote  cause  on  which  the  occurrence 
of  the  buffy  coat  depends  appears  to  be  an 
increased  action  in  the  circulating  system,  de- 
pendent on  increased  nervous  energy,  and  this 
is  capable  of  being  very  speedily  excited.  Thus 
it  has  happened*  that  blood  from  the  same 
orifice  drawn  into  four  cups  has  exhibited  this 
appearance  in  the  second  or  the  third  cup, 
and  not  in  the  first  or  last,  the  difference  being 
plainly  owing  to  a  faintness  felt  at  the  com- 
mencement and  termination  of  the  venesection. 
Thus  also  the  blood  of  healthy  horses  drawn 
immediately  after  a  smart  gallop  while  the  cir- 
culation is  powerful  and  rapid,  will  exhibit  a 
buffy  coat,  while  that  previously  abstracted 
will  of  course  shew  no  such  appearance. 
Scudamore,  it  is  true,  arrived  at  an  opposite 
result  in  the  case  of  a  young  man  whom  he 
bled,  and  after  causing  him  to  run  two  miles, 
bled  again.  Neither  before  nor  after  the  race 
was  the  blood  buffed,  but  it  is  obvious  that  such 
severe  exercise  after  depletion  would  exhaust 
rather  than  augment  the  powers  of  the  nervous 
and  circulating  systems.  Accordingly  he  found 
the  proportion  of  fibrine  diminished  in  the  blood 
last  drawn,  while  the  specific  gravity  of  the 
serum  was  increased  from  1-030  to  1'035,  thus 
shewing  how  large  a  quantity  of  moisture  must 
have  been  carried  off  by  perspiration. 

The  buffy  coat,  as  might  be  anticipated  from 
its  cause,  is  usually  found  in  connexion  with 
those  diseases  and  even  conditions  of  health 
in  which  vascular  action  is  preternaturally 
increased — in  the  active  stages  of  peripneu- 
mony,  in  pleurisy,  in  inflammatory  fever,  scar- 
latina and  the  eruptive  diseases  generally,  and 
very  uniformly  in  acute  rheumatism.  It  is 
also  occasionally  but  not  always  met  with  in 
the  biood  of  pregnant  women,  in  persons  of 
sanguine  temperament  and  full  habit,  and  those 
who  resort  to  frequent  bloodletting ;  in  chronic 
rheumatism,  gout,  enlargement  of  the  heart, 
and  other  affections  where  no  inflammation 
exists.  On  the  other  hand,  it  may  be  absent 
even  in  the  most  intense  inflammation;  for  the 

*  See  Hewson  on  the  blood,  vol.  i.  p.  82  et  seq. 


circulation  may  be  so  overcharged  either 
actually  or  relatively,  or  the  nervous  power  so 
oppressed,  that  the  requisite  degree  of  propul- 
sive force  is  not  exerted  by  the  heart  and 
arteries,  nor  the  vital  energy  on  which  slow 
coagulation  depends  imparted  to  the  blood. 
In  such  instances  the  buffed  coat  generally 
appears  on  a  second  or  third  repetition  of 
venesection. 

Louis  found  the  blood  covered  by  a  firm 
thick  buff  at  each  bleeding  in  nineteen  cases 
of  fatal  peripneurnony  out  of  twenty-four.  In 
two-fifths  it  was  cupped.  In  fifty-one  out  of 
fifty-seven  cases  of  recovery  the  blood  was 
buffed,  and  in  twenty- three  cupped.  In  nine 
tenths  of  rheumatic  patients  the  buff  was  firm 
and  thick. 

The  form  of  the  receiving  vessel,  the  degree 
of  motion  to  which  it  is  subjected,  and  the 
size  of  the  orifice  in  the  vein,  materially  in- 
fluence the  phenomenon.  M.  Belhomme,  the 
experimenter  under  M.  Recamier,  has  made 
aboutone  hundred  and  fifty  experiments  on  blood 
drawn  in  health  and  disease.  Ke  has  come  to 
the  conclusion  that  a  medium  orifice  one  line  in 
the  vein,  a  strong,  rapid,  and  continuous  jet  in 
the  form  of  an  arch,  and  a  narrow  vessel  for 
the  reception  of  the  blood,  are  the  external 
circumstances  most  favourable  for  producing 
the  buffy  coat.* 

Fibrine  is  more  abundant  in  buffed  than  in 
healthy  blood.  Dr.  Davy,  from  his  observa- 
tions, infers  that  there  is  no  constant  relation 
between  the  appearance  of  this  covering  and  the 
proportion  of  fibrine  in  the  crassamentum,  yet 
his  own  tabular  report  contradicts  him.  "  From 
all  the  examinations  we  have  made,"  says 
Thackrah,  who  has  made  many  experiments  to 
determine  this  point,  "  I  infer  without  hesita- 
tion that  buffed  blood  contains  a  considerably 
greater  proportion  of  fibrine  than  healthy 
blood."  This  is  a  fact  of  much  interest  and 
importance,  for  as  very  slight  aud  sudden  causes 
may  give  rise  to  the  formation  of  a  buffed  coat, 
we  are  thence  led  to  infer  that  the  quantity  of 
insoluble  matter  which  separates  from  liquor 
sanguinis  by  coagulation  is  variable,  and  that 
there  is  so  far  reason  to  believe  that  fibrine  and 
albumen  are  principles  convertible  into  each 
other. 

In  connection  with  the  appearances  depen- 
dent upon  the  slow  coagulation  of  fibrine,  I 
may  here  notice  the  occurrence  of  what  have 
been  termed  polypi,  or  more  recently  and  cor- 
rectly, false  polypi  in  the  hea't  and  larger  ves- 
sels. These  are  so  common,  that,  as  Haller  ob- 
serves, scarcely  a  body  is  met  with  in  which 
they  do  not  exist.  They  are  found  in  both 
auricles  and  both  ventricles  and  in  the  larger 
arteries  and  veins,  as  well  of  the  trunk  as  of  the 
extremities.  They  consist  essentially  of  fibrine, 
and  partake  of  all  the  varieties  that  are  obser- 
vable in  the  fibrinous  coat  of  buffed  blood. 
Haller  affirms,  as  usual,  supporting  his  opinion 
by  numerous  authorities,  that  these  have  been 
known  to  exist  even  during  life,  not  only  in 

*  See  also  Med.-Chir.  Trans,  vol.  xvi.  p.  296, 
note. 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


man  but  in  the  larger  warm-blooded  animals, 
and  adverts  to  a  disease,  la  gourme,  common 
among  horses,  which  arises  from  a  coagulation 
of  the  blood  in  the  large  arteries  and  veins  and 
in  the  heart.  Thackrah  is  of  the  same  opinion, 
and  Dr.  George  Burrows,  who  has  made  the 
changes  which  take  place  in  the  blood  when 
its  circulation  is  stopped  in  the  living  body, 
the  subject  of  the  Croonian  Lectures  of  the 
present  year,  states  that  "  there  can  be  but 
little  doubt  that  in  some  cases  the  blood  coa- 
gulates in  the  heart  during  life.  The  firmness 
of  the  clots  found  in  its  cavities  after  death — 
their  close  adhesion  to  the  lining  of  the  heart — 
the  presence  of  various  fluids  in  the  centre  of 
these  clots — the  occasional  organization  of  the 
coagulated  masses,  and  their  partial  conversion 
into  structures  which  are  similar  to  new  growths 
in  other  parts  of  the  body — are  facts  which 
lead  us  to  the  conviction  that  the  blood  often 
coagulates  in  the  heart  long  prior  to  death." 

That  such  coagulation  may  take  place  during 
life  I  am  willing  to  admit,  but  I  am  by  no 
means  led  to  the  conviction  that  such  an  event 
often  occurs.  To  the  formation  of  a  firm  coa- 
gulum  I  am  persuaded  that  rest  is  absolutely 
necessary,  and  I  must  consider  it  as  a  very  rare 
occurrence  that  the  contents  of  the  cavities  of  the 
heart  should  be  at  rest  during  life.  The  usual 
appearance  of  false  polypi  is  such  as  would 
take  place  in  blood  that  coagulated  very  slowly, 
whether  in  or  out  of  the  body.  Mr.  Thackrah 
has  proved  that  the  blood  when  at  rest  coagu- 
lates much  more  slowly  in  living  vessels, 
among  which  his  experiments  include  vessels 
recently  removed  from  living  animals,*  than  in 
those  that  are  dead ;  and  I  conceive  that  the 
human  body,  long  after  the  heart  has  ceased  to 
beat,  and  when  it  is,  in  the  common  accepta- 
tion of  the  term,  dead,  is  still  endowed,  like 
the  vessel  just  separated  from  the  living  animal, 
with  a  sufficient  share  of  vitality  to  keep  the 
blood  which  is  in  the  heart  and  larger  vessels 
in  a  fluid  state,  and  thus  to  permit  its  coagula- 
tion to  take  place  at  length  far  more  slowly 
than  under  ordinary  circumstances.  The  fol- 
lowing fact  will  perhaps  be  considered  to  have 
some  interest  as  bearing  on  this  point.  I  was 
engaged  in  the  post-mortem  examination  of  a 
gentleman  who  had  died  apoplectic  from  soft- 
ening of  the  brain,  which  had  given  rise  to  effu- 
sion into  the  ventricles  and  under  the  pia  mater; 
and  being  desirous  of  examining  the  fluid  thus 
effused,  I  collected  it  with  a  clean  sponge,  by 
successively  dipping  this  into  the  ventricles,  and 
squeezing  the  fluid  into  a  small  cup.  With  a 
view  to  increase  the  quantity,  I  used  the  sponge 
also  in  soaking  up  some  of  the  same  fluid 
which  had  been  caught  in  the  calvaria,  but 
was  somewhat  tinged  with  red  particles.  The 
cup  was  set  apart  till  the  conclusion  of  the  ex- 
amination, which  lasted  an  hour  and  a  half, 
when,  on  proceeding  to  transfer  its  contents  to 
a  phial,  I  was  not  a  little  surprised  to  find  that 
a  bulky  clot  of  a  rose  colour  and  perfectly  dis- 
tinct was  formed  in  the  fluid.  The  examina- 
tion in  question  took  place  twenty-two  hours 


421 

after  death.  As  long  as  galvanism  will  stimu- 
late the  muscular  structures  to  convulsive 
movement,  so  long  at  least  may  we  conceive 
such  a  portion  of  vitality  to  remain  us  will  in- 
fluence the  state  of  the  blood.  The  fluid  thus 
circumstanced  exhibits  the  same  phenomena, 
though  in  a  more  marked  degree,  which  we  ob- 
serve in  buffed  blood  out  of  the  body.  The 
red  particles  subside  and  leave  the  liquor  san- 
guinis  free  from  colour.  In  due  time  this 
separates  into  fibrine  and  serum  :  the  coagula- 
tion takes  place  uniformly  and  universally,  and 
in  the  larger  cavities  and  vessels  a  colourless 
clot  is  left,  which  is  moulded  into  their  exact 
shape.  The  serum  drains  off,  and  washes  away 
the  red  particles  into  the  more  depending  and 
distant  vessels.  Thus  it  is  that  where  we  find 
polypi  in  the  heart,  we  often  find  the  descend- 
ing aorta  and  the  vena  cava  inferior  filled  with 
fluid,  in  which  there  is  no  fibrine  at  all.  The 
firmness  of  a  polypus  affords  no  proof  that  it 
existed  during  life,  or  rather  before  respiration 
and  circulation  had  ceased ;  for  what  can  be 
firmer  than  the  buffed  coat  which  we  often  see 
formed  out  of  the  body  ?  Its  close  adhesion  to 
the  lining  of  the  heart  is  generally  in  appearance 
only,  and  is  occasioned  by  the  exactness  with 
which  it  has  adapted  itself  to  every  cavity  and 
sinus,  and  enveloped  every  column,  and  the 
force  with  which  the  heart  itself  has  contracted 
upon  it.  The  presence  of  fluid  in  the  centre, 
however  difficult  to  account  for,  is  also  occa- 
sionally met  with  in  the  crassamentum  of  blood 
abstracted  from  the  arm  ;*  and  even  purulent 
matter,  said  to  be  found  in  false  polypi,  is  oc- 
casionally formed  out  of  the  body.  "  In  some 
rare  cases  I  have  seen  the  fibrine,"  says  Andral, 
"  assume  a  different  aspect.  The  b!ood  had 
no  clot,  and  instead  of  it  we  observed  at  the 
bottom  of  the  basin  a  kind  of  homogeneous 
purulent  matter  of  a  deep  brown  or  dirty  grey 
colour,  and  rather  resembling  sanies  than 
blood." 

With  regard  to  the  existence  of  organization, 
it  seems  to  me  that  sufficient  distinction  has 
not  usually  been  made  between  those  cases 
where  the  lining  membrane  of  the  cavities  of 
the  heart  or  vessels  has  been  ruptured,  and 
which  in  so  far  are  of  the  character  of  aneu- 
rism, and  those  where  that  membrane  has  re- 
mained entire.  I  am  willing  to  admit  that 
where  there  is  a  lesion  of  surface,  adventitious 
growths  will  readily  spring  from  it;  but  their 
substance  is  furnished  from  the  structure  be- 
neath, and  not  from  the  circulating  fluid.  As 
an  instance,  I  may  mention  the  case  of  a  youth 
who,  being  in  perfect  health,  received  a  sudden 
shock  from  the  unexpected  discharge  of  a  pistol 
close  to  his  ear.  He  immediately  felt  conscious 
that  something  had  given  way  in  his  heart,  and 
from  that  hour  suffered  from  palpitation,  occa- 
sional syncope,  with  the  usual  symptoms  of 
obstructed  circulation,  and  died  of  general 
dropsy  at  the  end  of  eighteen  months.  On  ex- 
amination after  death  the  mitral  valve  was 
found  to  be  obstructed  by  a  fringe  of  excre- 
scences, originating  no  doubt  from  a  rupture  of 


*  Thackrah  on  the  Blood,  p.  85,  cxpt.  lii.  &  liii. 


See  Hewson,  p.  69  and  70. 


422 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


the  valve  itself,  which  had  taken  place  at  the 
time  of  the  sudden  surprise.  This  kind  of 
growth,  as  well  as  that  which  is  formed  on  the 
inflamed  surface  in  endocarditis,  has  a  suffi- 
ciently evident  origin.  We  can  also  readily 
account  for  organized  structures  arising  from 
aneurisms  of  the  heart  or  arteries,  accidental 
wounds  of  the  latter  vessels,  ruptures  of  their 
inner  membrane  by  ligatures,  or  its  destruction 
by  inflammation.  I  can,  however,  imagine 
nothing  more  unlikely  than  that  an  insulated 
mass  of  fibrine  owing  its  origin  to  the  mere 
coagulation  of  the  blood  from  rest,  and  there- 
fore only  by  gravitation  brought  in  contact  with 
the  sides  of  the  vessel  which  may  contain  it, 
should  assume  an  organized  structure,  and  that, 
too,  at  a  time  when  the  powers  of  life  are  so 
much  enfeebled  that  the  heart  itself  ceases  to 
perform  its  office.  I  have  looked  carefully  for 
unequivocal  signs  of  vitality  in  these  false 
P°typi>  and  I  confess  that  I  have  never  been 
able  to  satisfy  myself  of  its  existence. 

The  albumen  has  not  been  demonstrated  to 
be  subject  to  alteration  in  quality.  Its  distin- 
guishing characteristic  of  coagulating  by  heat  is 
preserved  even  after  it  has  become  in  the  high- 
est degree  offensive  from  putridity.*  It  may 
be  excessive  or  defective  in  proportion,  and  M. 
Gendrin  has  shewn  that  under  inflammation 
of  the  system,  the  serum  contains  twice  as  much 
albumen  as  in  the  healthy  state.  Andral  affirms 
that  even  by  the  touch,  we  may,  from  its  vis- 
cidity, recognise  serum  that  is  surcharged  with 
albumen.  Its  specific  gravity,  however,  of 
which  the  French  writers  seem  to  take  little 
note,  would  be  a  far  better  guide,  and  would 
indicate  alike  the  defect  as  the  excess  of  this 
principle.  M.  Gendrin  has  occasionally  ob- 
served a  mucous  layer  either  at  the  bottom  of 
the  serum,  or  suspended  in  it.  This  is,  in 
all  probability,  a  minute  portion  of  fibrine  se- 
parating in  the  form  of  a  flocculent  cloud ;  for 
serum  is  capable  of  holding  a  certain  portion  of 
fibrine  in  solution,  which  after  a  time  separates 
from  it.  This  was  first  proved  by  Dr.  Dowler,f 
who,  on  pressing  the  buffed  coat  of  blood,  ex- 
tracted from  it  a  liquid  serum,  which,  on  being 
allowed  to  rest  for  some  time,  exhibited  signs 
of  coagulation.  With  regard  to  the  relative 
proportions  of  the  serum  and  the  clot,  I  have 
proved  elsewhere  J  that  this  depends  much  on 
the  vessel  into  which  the  blood  is  received.  I 
shall  show  experimentally,  however,  in  treating 
of  diseased  kidney,  that  an  opposite  state  to 
that  above  alluded  to  as  occurring,  according  to 
M.  Gendrin,  in  inflammation,  takes  place  under 
certain  forms  of  disease  where  albumen  is 
passing  out  of  the  system  by  the  urinary  pas- 
sages. Thackrah  lays  it  down  as  a  law,  to 
which  he  has  found  no  exception,  that  in  all 
cases  in  which  the  proportion  of  fibrine  is  con- 
siderably above  the  normal  standard,  the  solid 
matter  in  the  serum  is  below  it.  He  cites  ten 
examples  in  proof  of  his  assertion,  and  puts  it 

*  See  a  paper  by    IVf .  Vauquelin,    in  the  16th 
vol.  of  the  Ann.  de  Chimie,  new  series,  p.  363. 
t  See  Med.-Chir.  Trans,  vol.  xii.  p.  89. 
j  Med.-Chir.  Trans,  vol.  xvi.  p.  296, 


as  a  question  whether  we  may  not  hence  sup- 
pose that  the  albumen  is  taken  from  the  serum 
for  the  formation  of  fibrine  ?  The  fact  itself, 
however,  requires  confirmation,  being  in  direct 
opposition  to  M.Gendrin's  statement,  that  the 
proportion  of  albumen  is  greatly  increased  in  an 
inflammatory  condition  of  the  system,  which  is 
precisely  that  condition  when  in  general  we 
find  buffed  blood,  and  therefore,  according  to 
Thackrah,  an  increase  in  the  proportion  of 
fibrine. 

The  haematosine  is  the  least  destructible  of 
all  the  elements  of  the  blood,  retaining  its  quali- 
ties in  that  fluid  after  having  been  kept  for 
several  years.  It  is  liable  to  much  variety  in 
its  proportion,  and  in  all  those  diseases  and 
states  of  system  in  which  hemorrhages  occur,  it 
gradually  diminishes,  at  least  to  a  certain  point, 
in  proportion  to  their  extent  and  duration. 
In  what  part  of  the  system  the  red  particles 
are  elaborated  remains  for  the  present  a  mys- 
tery. That  they  are  reproduced  slowly  is 
manifested  by  the  fact  that  those  who  have  suf- 
fered large  losses  of  blood,  remain  exsanguine 
for  many  months  or  even  years  afterwards. 
The  same  conclusion  may  also  be  deduced 
from  the  circumstance  that  women  have  a 
smaller  proportion  of  red  particles  than  men, 
the  difference  having  been  shewn  by  M.  Le- 
canu  to  be  attributable  to  the  monthly  loss 
which  they  habitually  experience.  Besides 
change  of  colour,  to  which  the  red  particles  are 
liable  during  disease,  and  which,  among  other 
causes,  may  arise  from  an  altered  proportion  in 
the  saline  matters  contained  in  the  blood,  they 
also  appear  to  undergo  structural  alterations. 
In  fevers,  in  malignant  diseases,  in  sea-scurvy,  in 
cases  of  poisoning,  and  of  asphyxia  from  light- 
ning, a  permanently  liquid  state  of  the  blood 
occurs,  wherein  the  colouring  matter  of  the 
globules  appears  to  have  lost  its  character  of 
insolubility  in  the  serum,  and  to  be  capable  of 
percolating  those  tissues  which  are  otherwise 
destined  to  contain  it.  Passive  hemorrhages, 
petechiae,  and  ecchymoses,  are  the  results  during 
life ;  and,  after  death,  a  stained  condition  of  the 
lining  membrane  of  the  heart,  the  arteries,  and 
veins,  which  has  often  been  mistaken  for  vas- 
cular congestion  of  these  parts. 

The  oil  or  unctuous  soft  solid  which  is  now 
ascertained  to  be  one  of  the  constituents  of 
healthy  blood,*  is  liable  to  morbid  increase 
under  various  forms  of  disease.  Morgagni  cites 
two  cases  of  malignant  fever  in  which  the  serum 
was  milky.  Hewson,  besides  enumerating  in- 
stances to  be  met  with  in  authors,  gives  three 
cases  sent  him  by  medical  friends :  one  of 
amenorrhoea  with  dyspepsia  and  vicarious  dis- 
charge of  blood  by  vomit  and  stool ;  another  of 
violent  and  continued  epistaxis,  and  a  third  of 
dyspepsia  with  slight  asthma.  In  all  three  cases 
there  were  symptoms  of  plethora ;  but  milky 
serum  is  by  no  means  necessarily  connected 
with  this  state.  The  most  marked  instance  that 
I  have  met  with  was  in  a  case  of  diabetes,  where 
bleeding  was  several  times  repeated  at  long  in- 
tervals, and  on  each  occasion  the  same  morbid 

*  Med.-Chir.  Trans,  vol.  xvi.  p.  46. 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


condition  of  serum  was  observed.  This  was  quite 
opaque,  and  nearly  as  white  as  milk;  and  on 
standing  for  a  few  hours,  a  film  of  mattter  re- 
sembling cream  covered  the  surface.  The  clot 
could  not  be  seen  when  it  was  scarcely  a  tenth 
of  an  inch  beneath  the  surface.  It  had  a 
firm,  very  thick,  white  coat  of  fibrine,  and  the 
red  particles  were  almost  diffluent  beneath. 
The  patient,  a  female,  could  not  be  called  ple- 
thoric, having  been  the  subject  of  her  emaci- 
ating complaint  more  than  a  year  and  a  half. 
Milky  serum,  though  of  a  far  less  marked  cha- 
racter, having  occurred  in  persons  who  have 
been  bled  shortly  after  making  a  hearty  meal, 
the  notion  has  been  entertained  that  it  is  owing 
to  the  passage  of  liquid  chyle  into  the  circu- 
lation. This  was  Ilaller's  opinion,  while  others 
have  attributed  its  appearance  fo  admixture  of 
fat.  To  the  former  notion  it  may  be  objected, 
that  whereas  it  is  certain  that  the  milky  appear- 
ance of  serum  is  owing  to  the  presence  of  oily 
particles,  it  is  very  doubtful,  from  the  discord- 
ant opinions  of  eminent  chemists,  whether  the 
chyle  contains  more  oily  matter  than  the  blood 
itself.  Berzelius,  indeed,  makes  its  solid  part 
to  consist  of  more  than  twenty-one  per  cent,  of 
fat,  and  Raspail  considers  it  as  differing  little 
from  milk.  Prout,  however,  whose  analysis  is 
adopted  by  Turner,  only  admits  an  unappre- 
ciable  trace  of  oily  matter  in  chyle,  and  makes 
its  composition  differ  little  from  blood  ex- 
cept as  respects  the  absence  of  red  particles. 
In  milky  serum  the  oil  exists  in  superabun- 
dance at  the  expense  of  the  albumen,  which,  in 
all  the  specimens  I  have  examined,  has  been 
remarkably  deficient  in  proportion,  its  specific 
gravity  varying  from  1*019  to  1-024.  This  cir- 
cumstance naturally  leads  to  a  question  whether 
this  oil  may  not  owe  its  origin  to  some  chemical 
change  in  the  albumen  itself,  of  which  it  seems 
to  supply  the  place.  The  «  remarkable  blood ' 
described  by  M.  Caventou,*  and  alluded  to  by 
M.  Raspail,  f  which  was  evidently  nothing 
more  than  blood  with  milky  serum,  affords  ad- 
ditional ground  for  supposing  that  such  a 
change  takes  place.  "  This  blood  issuing  from 
the  vein  was  turbid,  of  a  pale  dirty  red  colour, 
and  became  marled  and  of  a  whitish  red  as  it 
cooled  in  the  basin,  and  some  drops  which  fell 
on  the  floor  assumed  this  colour  in  a  few 
seconds,  and  looked  like  drops  of  chocolate 
made  with  milk.  After  half  an  hour  a  coagulum 
of  moderate  size  was  formed  in  it,  which  floated 
in  a  large  quantity  of  a  white  opaque  fluid  ex- 
actly like  milk."  Raspail,  who  had  evidently 
never  seen  a  marked  example  of  milky  blood, 
gives  the  following  fanciful  explanation  of  the 
appearance.  "  Under  the  influence,  or  in  the 
absence  of  one  of  the  causes  which  together 
produce  the  circulation,  an  acid  had  been 
formed,  which,  saturating  the  alkaline  men- 
struum of  the  albumen,  had  caused  it  to  coagu- 
late. Now  this  irregular  coagulation  could  not 
take  place  without  disguising  the  colour  of  the 
blood  and  rendering  it  rose-coloured,  while  it 
would  give  the  serum  the  appearance  of  milk." 
If  the  albumen  had  really  been  coagulated  by 

*  Annalrs  de  Ohiroie,  vol.  xx»ix.  p.  288. 
t  Sect.  941. 


423 

an  acid,  a  distinct  clot  would  not  have  been 
formed  by  it,  but  a  curdled  precipitate;  nor 
would  the  serum  have  borne  any  resemblance 
to  milk.  But  what  is  important  as  confirming 
my  view  respecting  the  conversion  mentioned 
above,  M.  Caventou,  to  his  great  astonishment, 
could  not  find  any  albumen  in  the  milky  serum 
here  described.  The  probability  of  this  change 
is  heightened  by  the  consideration  that  some- 
thing analogous  must  necessarily  occur  in  the 
formation  of  true  milk,  the  oil  of  which,  when 
separated  as  butter  and  melted  to  clarify  it 
from  curd,  remarkably  resembles  the  oil  of 
milky  serum. 

The  attention  of  pathologists  to  the  salts  of 
the  blood,  which,  considering  the  visible  effects 
they  produce  on  this  fluid,  had  been  strangely 
neglected,  has  of  late  years  been  roused  by  the 
observations  of  Dr.  Stevens,  who  certainly  may 
claim  the  merit  of  having  advanced  our  know- 
ledge of  facts  on  this  subject.  It  appears  that 
in  the  last  stages  of  tropical  fevers  the  saline 
ingredients  of  the  blood  are  so  much  diminished 
that  they  are  no  longer  capable  of  giving  a  red 
colour  to  the  haematosine.  The  black  blood 
that  is  found  in  the  heart  after  death  from 
either  the  climate  fever  or  the  African  typhus, 
remains  black  even  in  an  atmosphere  of  pure 
oxygen,  but  it  instantly  changes  colour  when  we 
add  it  to  a  clear  fluid  that  contains  even  a  small 
portion  of  any  neutral  salt.  Nor  is  it  in  fever 
alone  that  this  deficiency  of  salts  is  observed. 
Dr.  O'Shaughnessy  has  shewn  that  it  likewise 
exists  in  malignant  cholera,  and  it  is  probable 
that  in  sea-scurvy,  and  in  those  analogous  dis- 
eases produced  by  want  and  unwholesome 
nourishment,  a  similar  state  occurs. 

The  saline  matters  may  be  in  excess  as  well 
as  in  defect,  and  this  is  marked  by  excitement 
of  the  circulating  system,  and  either  local  de- 
terminations or  general  febrile  disturbance.  The 
stimulant  effect  of  saline  springs  has  been  known 
time  out  of  mind,  while  the  thirst  and  heat  pro- 
duced by  the  too  copious  use  of  common  salt 
is  in  every  body's  experience.  If  we  couple 
these  facts  with  the  certainty  that  the  neutral 
salts  will  pass  unchanged  through  the  circu- 
lation so  as  to  admit  of  detection  in  the  urine, 
we  may  infer  that  their  superabundance  in  the 
bood  is  not  only  a  possible,  but,  in  all  proba- 
bility, a  frequent  occurrence.  They  are  occa- 
sionally found  after  death  deposited  in  a  crys- 
talized  form,  as  was  observed  by  Sir  Everard 
Home,  who,  in  dissecting  an  aneurismal  tumour, 
found  a  mass  of  crystals,  which  were  analyzed 
by  Mr.  Faraday,  and  are  stated  to  have  been 
Salts  usually  met  with  in  the  blood. 

Having  thus  concluded  such  remarks  as  the 
present  state  of  our  knowledge  has  enabled  me 
to  offer  respecting  the  morbid  changes  which 
take  place  in  the  separate  constituents  of  the 
blood,  I  now  proceed  to  notice  some  of  the 
more  important  diseases  in  which  those  changes 
have  been  observed  to  occur. 

Inflammation. — The  usual  appearances  of 
blood  in  inflammatory  diseases  have  already 
been  described  in  treating  of  the  buffed  coat. 
The  crassamentum  is  commonly  supposed  to 
be  increased  in  bulk,  but  this  is  somewhat 
doubtful ;  and  indeed  it  so  much  depends  upon 


424 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


extraneous  circumstances,  such  as  the  form  of 
the  vessel  in  which  the  blood  is  received,  the 
time  allowed  for  the  contraction  of  the  clot, 
which  it  is  well  known  goes  on  for  many  hours, 
and  even  the  quantity  abstracted,  that  no  accu- 
rate deduction  can  be  drawn  from  its  appear- 
ance. The  collection  of  the  fibrine  itself  is 
easily  effected,  and  it  will  thus  be  perceived 
that,  under  inflammation,  it  is  more  abundant 
than  in  the  normal  state.  Scudamore  has  made 
numerous  experiments  on  the  relative  quantity  of 
fibrine  contained  in  healthy  and  diseased  cras- 
samentum,  and  the  following  short  list  selected 
from  them  satisfactorily  establishes  this  fact. 
In  1000  grs.  of  clot  as  deduced  from 
eight  specimens  of  healthy  blood, 

average  of  dry  fibrine 3*53  grs. 

Maximum  4-43,  minimum  2'37 
Slight  pleurisy,  blood  slightly  buffed     7*05 

Pain  in  the  side,  ditto 11-37 

Cough    7-24 

Acute  gout,  blood  not  buffed,  firm 

texture     5'88 

Disease  not  named,  clot  compact, 

buffed,  and  cupped    12*41 

Ditto 13-73 

Average 9-62 

Mr.  Jennings,  in  his  report  on  the  blood  in 
the  Transactions  of  the  Provincial  Medical  As- 
sociation for  1834,  likewise  gives  a  table,  the 
result  of  which  is,  that  in  eight  cases  of  in- 
flammation, the  proportion  of  fibrine  in  the 
blood  was  increased  from  2*1,  which  is  Le- 
canu's  standard  of  health,  to  9,  8,  11,  6,  5-3, 
7,  6-9,  7 ;  average  7-525,  and  that  the  alkaline 
salts  were  diminished  from  8'37,  the  healthy 
standard,  to  4'9,  4*8,  5-1,  4-3,  4-2,  4-4,  4,  5'6; 
average  4-61. 

Among  all  the  varieties  of  inflammation  it  is 
in  acute  rheumatism  where  we  find  the  blood 
most  decidedly  loaded  with  fibrine.  Owing  to 
the  powerful  action  of  the  heart  and  arteries,  it 
is  intensely  arterial  in  character,  and  sometimes 
issues  from  the  vein  with  a  distinct  pulsation. 

Fever. — In  those  fevers  which  arise  from 
marsh  miasmata  or  from  contagion,  it  is  an 
opinion  held  by  Dr.  Stevens,  and  supported  at 
great  length  in  his  work  on  the  blood,  that  a 
diseased  condition  of  that  fluid  is  the  first  in 
the  train  of  symptoms  which  occur,  and  the 
immediate  cause  of  those  which  follow.  The 
blood  itself,  says  Dr.  Stevens,  is  both  black 
and  diseased  even  before  the  attack.  During 
the  cold  stage  it  is  very  dark.  When  first 
drawn  it  has  a  peculiar  smell,  and  coagulates 
almost  invariably  without  any  crust.  There  are 
black  spots  on  the  surface  of  the  crassamentum, 
the  coagulum  is  so  soft  that  it  can  easily  be 
separated  by  the  fingers,  and  during  its  forma- 
tion a  large  quantity  of  the  black  colouring 
matter  falls  to  the  bottom  of  the  cup.  In  the 
hot  stage  it  becomes  more  red,  and,  in  some 
cases,  it  is  even  florid  for  a  time,  but  during  the 
remission  it  is  darker  in  colour  than  the  blood 
of  health,  and  decidedly  diseased  in  all  its 
properties.  In  milder  cases,  the  blood  which 
is  drawn  may  coagulate  without  a  crust  on  the 
surface ;  but  in  the  more  severe  forms  of  this 
fever,  when  the  blood  was  drawn  at  an  advanced 
period  of  the  disease,  a  part  of  the  albumen 


coagulated  on  the  surface  of  the  fibrine,  and 
formed  a  diseased  mass,  which  in  appearance 
had  a  greater  resemblance  to  oatmeal  gruel 
than  to  blood  drawn  from  a  healthy  person. 
The  serum  which  separated  was  also  diseased  ; 
it  had  a  brownish  colour,  and  in  some  cases 
an  oily  appearance,  which  is  never  met  with 
in  the  clear  serum  of  healthy  blood.  In 
the  climate  or  seasoning  fever  of  the  West 
Indies,  which  is  not  considered  contagious,  but 
a  fever  of  excitement,  the  blood  drawn  in  the 
first  stage  flows  from  the  vein  with  great  force, 
but  is  neither  cupped  nor  buffed.  It  is  so  florid, 
being  charged  with  salts  which  ought  to  have 
been  removed  by  the  organs  of  secretion,  that 
it  resembles  arterial  blood.  The  fibrine  coagu- 
lates firmly,  and  in  some  cases  the  serum  which 
separates  from  it  has  a  bright  arterial  colour, 
the  colouring  matter  being  not  merely  diffused 
through,  but  combined  with  the  serum.  During 
the  progress  of  this  kind  of  fever  the  blood  loses 
a  large  proportion  of  its  fibrine  and  albumen, 
and  becomes  so  thin  that  it  oozes  from  the  mu- 
cous membranes  without  any  abrasion  of  sur- 
face, and  in  the  last  stage  turns  quite  black  from 
a  diminution  in  the  proportion  of  its  salts. 

Such  are  the  appearances  which  the  blood 
presents  in  the  more  severe  fevers  of  hot  cli- 
mates. In  this  country,  at  the  commencement 
or  stage  of  depression  the  blood  is  dark  and 
tarry,  coagulates  quickly,  and  forms  a  large 
clot  with  but  little  serum.  As  the  stage  of 
excitement  advances,  the  blood  becomes  thinner 
and  more  florid,  and  flows  more  freely.  Coa- 
gulation takes  place  more  slowly,  and  a  buffy 
crust  is  frequently  formed  on  the  surface  of  the 
clot.  In  the  latter  stage,  when  the  powers 
are  giving  way,  the  blood  becomes  thinner, 
darker,  and  more  dissolved.  It  scarcely  coa- 
gulates at  all,  and  is  deficient  in  saline  matter, 
and  probably  also  in  fibrine,  thus  nearly  re- 
sembling menstrual  blood,  or  the  fluid  mixture 
of  serum  and  red  particles,  already  mentioned 
as  often  found  in  the  larger  vessels  after  death. 
Such  are  the  alterations  which  the  blood  usually 
undergoes  in  the  different  stages  of  simple  con- 
tinued fever,  but  in  its  more  malignant  forms,  as 
in  typhus,  the  blood  is  generally  very  watery, 
even  from  the  commencement.  As  the  disease 
advances,  it  gradually  loses  its  power  of  coagu- 
lation, and  in  the  last  stage  seems  almost  en- 
tirely deprived  of  fibrine. 

Magendie  has  artificially  produced  an  analo- 
gous state  of  blood  by  injecting  putrid  liquids 
into  the  veins  of  animals,  and  the  speedily  fatal 
disease  which  he  thus  caused  had  a  strong  ana- 
logy with  typhous  fever.* 

To  Dr.  Stevens  belongs  the  merit  of  having 
especially  directed  general  attention  to  the  cir- 
cumstance that  the  saline  matter  of  the  blood 
gradually  disappears  in  the  progress  of  fever, 
and  is  almost  entirely  lost  in  its  last  stage. 
This  he  ascertained  by  direct  experiment,f 
and  his  facts  have  since  been  confirmed  by 
Jennings,  who  in  the  interesting  report  already 
alluded  to,  gives  an  analysis  of  the  blood 
in  six  cases  of  continued  fever,  in  which  the 

*  Journal  de  Physiologie,  torn.  iii.  p.  83. 
t  On  the  Blood,  &c.  page  209. 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


alkaline  salts  were  found  diminished  in  the  fol- 
lowing proportions : — 
In  healthy  serum,  according  to  Lecanu, 

salts 8-10 

In  the  serum  of  a  male,  aged  31,  first  day 

of  fever,  salts    4 

Ditto  ditto  aged  34,  first  day 

of  fever,  salts 5 

Ditto  female,  aged   14,   fourth 

day  of  fever,  salts    4'2 

Average  of  three  other  cases 4'4 

Scurvy. — It  seems  to  be  the  universal  opi- 
nion of  those  who  have  seen  and  written  on 
scurvy,  that  it  owes  its  origin  to  a  morbid 
change  in  the  fluids,  and  especially  in  the 
blood ;  and  even  those  who  have  been  the  most 
strenuous  opposers  of  the  humoral  pathology 
in  general,  among  the  most  celebrated  of  whom 
we  may  reckon  Willis,  Hoffmann,  Boerhaave, 
Cullen,  and  Sir  John  Pringle,  have  made  an 
exception  in  favour  of  this  disease.  Notwith- 
standing this  general  belief  there  has  been  no 
attempt  up  to  the  present  time  at  any  chemical 
examination  of  the  properties  of  scorbutic 
blood,  and  we  have  only  the  general  obser- 
vation made  by  the  surgeons  of  Lord  Anson's 
expedition,  (Messrs.  Ettrick  and  Allen,)  that  in 
the  beginning  of  the  disease  it  flows  from  the 
arm  in  different  shades  of  light  and  dark 
streaks ;  that  as  this  advances,  it  runs  thin  and 
black,  and  after  standing  turns  thick  and  of  a 
dark  muddy  colour,  the  surface  in  many  places 
being  of  a  greenish  hue,  without  any  regular 
separation  of  its  parts  ;  that  in  the  third  de- 
gree of  the  disease  it  is  as  black  as  ink,  and 
though  kept  stirring  in  the  vessel  for  many 
hours,  its  fibrous  parts  have  only  the  appear- 
ance of  wool  or  hair  floating  in  a  muddy  sub- 
stance ;  and  that  in  dissected  bodies  the  blood 
in  the  veins  is  so  fluid  that  by  cutting  any  con- 
siderable branch,  the  part  to  which  it  belongs 
may  be  emptied  of  its  black  and  yellow  liquor, 
the  extravasated  blood  being  precisely  of  the 
same  kind.  The  prevalence  of  scurvy  where 
there  has  been  a  long-continued  use  of  salted 
provisions  has  given  rise  to  the  supposition* 
that  the  salt  itself  actually  finds  its  way  into 
the  circulation,  and  acts  as  it  is  known  to  act 
on  blood  out  of  the  body  by  preventing  its 
coagulation.  This,  however,  is  very  evidently 
not  the  case,  first,  because  salt  provisions  are 
not  necessary  to  its  production,  since  scurvy 
has  often  made  its  appearance  where  no  salt 
provisions  were  used;  as,  for  instance,  in  the 
Milbauk  Penitentiary  in  181 9,  where  the  diet 
consisted  of  pease,  barley  soup,  and  brown 
bread  ;  and,  secondly,  because  the  appearance 
of  the  blood,  especially  as  the  disease  ad- 
vances, is  exactly  the  reverse  of  what  it  would 
be  on  the  addition  of  salt,  which,  instead  of 
making  it  black,  and  causing  it  on  standing 
to  become  thick,  muddy,  and  of  a  greenish 
hue,  would  impart  to  it  a  fine  scarlet  tint  that 
would  remain  permanent  until  it  began  to 
putrefy.  Since  the  modern  advances  in  ani- 
mal chemistry,  opportunities  for  examining  the 
blood  in  true  scurvy  have  been  very  rare ;  and 

*  Jennins's  Report. 


425 

it  is  therefore  the  more  to  be  regretted  that 
Drs.  Latham  and  Roget,  philosophers  every  way 
so  competent  to  determine  the  precise  morbid 
changes  which  it  undergoes,  did  not,  when  they 
had  it  in  their  power,  make  a  particular  ex- 
amination of  it.  Venesection,  it  seems,  was 
practised  at  the  Penitentiary  in  a  few  cases, 
but  nothing  is  stated  respecting  the  appearance 
which  the  blood  assumed.*  The  description 
of  Lord  Anson's  surgeons  does  not  by  any 
means  apply  to  the  blood  which  is  found  in 
purpura  haemorrhagica,  a  complaint  that  was, 
prior  to  the  appearance  of  Dr.  Bateman's  work 
on  diseases  of  the  skin,  generally  considered 
closely  allied  to  scurvy.  In  two  cases  of  pur- 
pura related  by  Dr.  Parry,f  of  Bath,  blood 
drawn  from  the  arm  exhibited  a  tenacious 
contracted  coagulum  covered  with  a  thick  coat 
of  lymph ;  and  in  one  instance  which  occurred 
under  my  care,  where  the  patient,  a  man  of 
forty-five  years  of  age,  had  most  of  the  sym- 
ptoms of  sea-scurvy,  such  as  general  cachexia, 
with  anasarca  of  the  lower  limbs,  great  depres- 
sion of  spirits  and  prostration  of  strength,  ex- 
tensive ecchymosis  on  the  trunk  and  the  ex- 
tremities, fetid  breath  and  extravasations  of 
blood  from  the  gums,  the  stomach,  and  the 
bowels,  as  well  as  from  a  large  foul  ulcer  on 
the  leg;  a  copious  venesection  demonstrated 
that  the  blood  had  not  in  any  degree  lost  its 
crasis,  the  crassamentum  being  covered  with  a 
thick  buffy  coat,  and  having  as  much  firmness 
as  is  usual  under  the  existence  of  such  a  state. 
It  is  proper  to  observe  that  Lind's  description 
of  the  blood  in  scurvy  differs  from  that  of  Lord 
Anson's  surgeons,  as  he  found  it  generally  either 
natural  or  buffed.J 

Jaundice.  —  In  jaundice  the  blood,  both 
arterial  and  venous,  is  tinged  with  bile,  and 
this  is  apparent  not  only  in  the  serum, 
but  still  more  strikingly  in  the  crassamentum, 
provided  it  be  covered  with  a  buffed  surface. 
If  this  be  removed  and  dried  in  a  state 
of  tension,  it  exhibits  a  deep  yellow  hue, 
particularly  when  viewed  by  transmitted  light. 
Although  the  bile  is  thus  rendered  very 
visible  in  jaundiced  blood,  yet,  owing  to  its 
combination  with  albumen,  which  defends  it 
from  the  action  of  acids,  it  is  difficult  of  de- 
tection by  chemical  re-agents,  so  that  many 
chemists  of  eminence  have  sought  in  vain  to 
ascertain  its  presence.  Lassaigne,  however, 
succeeded  in  demonstrating  that  the  colouring 
matter  of  the  bile  is  really  to  be  found  in  the 
circulation,  and  Berzelius  tells  us  that  Collard 
and  Martigny  pretend  to  have  discovered  even 
the  resin  of  bile  in  jaundiced  blood.  M.  Le- 
canu has  more  recently  confirmed  these  facts, 
and  Mr.  Kane  has  verified  his  results. §  To 
the  medical  inquirer  who  does  not  follow  the 
minutiae  of  animal  chemistry,  the  identity  of 
the  colouring  matter  in  the  serum  of  jaundiced 

*  Account  of  the  Disease  lately  prevalent  at  the 
General  Penitentiary,  by  P.M.  Latham, M.D.  1823, 
p.  39. 

t  Edinburgh  Medical  and  Surgical  Journal, 
vol.  v.  p.  7. 

jf  Lind  on  Scurvy,  page  512. 

§  Dublin  Journal,  vol.  ii.  p.  346. 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


426 


blood  with  that  of  the  bile  itself  will  be  ren- 
dered sufficiently  evident  by  adding  to  it  an 
equal  quantity  of  sulphuric  acid  diluted  with 
twice  its  bulk  of  water.  The  serum  will  thus 
change  its  yellow  hue  for  the  characteristic 
green  colour  of  acid  bile.  Experimentalists 
have  failed  in  producing  this  effect,  being  pro- 
bably misled  by  having  found  that  the  small 
proportion  of  acid  which  is  required  to  strike 
a  green  colour  with  urine  charged  with  bile, 
produces  no  such  effect  when  added  to  jaun- 
diced serum. 

Disease  of  the  kidney. — In  those  organic 
diseases  of  the  kidney  which  are  characterized 
by  anasarca  and  the  passing  of  urine  coagu- 
lable  by  heat  and  acids,  the  albumen  of  the 
blood  is  more  or  less  deficient  in  proportion; 
and  this  is  marked  by  a  corresponding  dimi- 
nution in  the  specific  gravity  of  the  serum. 
In  a  letter  to  Dr  Bright,  published  in  the  first 
volume  of  that  author's  Reports  of  Medical 
Cases,  page  83,  Dr.  Bostock  states,  in  re- 
ference to  the  blood  in  these  diseases,  that 
the  crassamentum  was  for  the  most  part  co- 
vered with  a  thick  buffy  coat,  and  was  gene- 
rally of  a  firm  consistence.  The  appearance 
of  the  serum  was  more  varied.  It  was  occa- 
sionally turbid,  and  upon  standing  for  twenty- 
four  hours  a  white  creamy  substance  rose  to 
the  surface ;  but  no  proper  oily  matter  could 
be  detected  in  it.  On  exposing  it  to  heat,  it 
coagulated  in  the  ordinary  manner,  except  that 
the  coagulum  seemed  to  contain  an  unusual 
number  of  cells,  and  that  a  greater  quantity 
of  serosity  separated  from  it.  "  I  think  I  may 
venture  to  say,"  adds  the  writer,  '•  that  the 
serum  generally  in  these  cases  contained  less 
albumen  than  in  health,  although  I  am  not 
able  to  state  precisely  the  amount  of  this  dif- 
ference. The  serosity  which  drained  from  the 
coagulated  albumen  on  being  evaporated  was 
found  to  consist  in  part  of  an  animal  matter 
possessing  peculiar  properties  which  seemed 
to  approach  to  those  of  urea ;  it  was  partially 
soluble  in  alcohol,  and  was  acted  upon  in  a 
somewhat  similar  manner  by  nitric  acid." 

The  above  remarks  were  made  on  specimens 
of  blood  furnished  from  time  to  time  by  Dr. 
Bright.  The  number  is  not  stated,  nor  was  the 
specific  gravity  of  the  serum  taken.  Dr.  Bos- 
tock gives  a  case,  however,  (page  85,)  where, 
after  stating  that  the  crassamentum  was  re- 
markably buffed  and  cupped,  he  adds,  «  The 
serum  was  also  worthy  of  attention,  as  taken 
in  connexion  with  the  state  of  the  other  fluids. 
Its  specific  gravity  was  almost  exactly  the  same 
with  that  of  the  urine,  being  no  more  than 
1-013,  which  I  believe  to  be  lower  than  had 
ever  occurred  to  me  in  the  numerous  expe- 
riments which  I  have  made  upon  this  sub- 
stance. We  have  here,  therefore,  an  example 
of  blood  exhibiting  a  very  great  deficiency  of 
albumen,  at  the  same  time  that  we  observe  the 
mode  in  which  it  passes  off  from  the  system 
by  means  of  the  kidney,  while  this  organ  has 
its  appropriate  office  of  secreting  urea  nearly 
suspended.  I  regret  that  I  did  not  attend 
particularly  to  the  specific  gravity  of  the  other 
specimens  of  dropsical  serum  which  you  sent 


me.  From  some  incidental  remarks  in  my 
notes,  I  suspect  that  its  specific  gravity  would 
have  been  found  lower  than  ordinary ;  but  it 
is  a  circumstance  which  I  shall  be  anxious  to 
ascertain  when  any  opportunity  occurs."  This 
suspicion  is  completely  confirmed  by  other 
cases  that  have  occurred  to  myself,  in  which 
the  fact  was  also  established  beyond  doubt, 
that  the  animal  matter  found  by  Dr.  Bostock 
in  the  serosity  was  not  merely  an  approach  to 
urea,  but  that  principle  itself  possessing  all  its 
usual  characters.  The  following  may  serve  as 
an  example  of  light  serum. 

William  Squires,  aged  54,  labouring  under  or- 
ganic disease  of  the  kidneys  and  chronic  bron- 
chites  with  anasarca,  had  for  many  months 
voided  urine  which  coagulated  on  the  appli- 
cation of  heat  or  the  addition  of  nitric  acid. 

The  specific  gravity  of  his  blood  at 

88  Fahr.  was  1-041 

Do.     Serum    at    68  1-021 

heal  thy  standard  1-030. 

This  blood  contained  in  1000  parts, 
3-845  fibrine : 

healthy  standard  2- 1  to  3' 56 
55-000  albumen : 

healthy  standard  65  to  69 
In  this  case  100  grains  of  urine  contained  6'666 
albumen.  There  was  consequently  nearly  one 
eighth  as  much  albumen  in  the  urine  as  in  the 
blood,  and  the  patient  lost  as  much  of  that  con- 
stituent daily,  as  if  he  had  been  bled  to  the 
extent  of  four  ounces. 

The  folio  wing  cases  are  from  notes  with  which 
I  have  been  favoured  by  Dr.  G.  H.  Barlow, 
who  has  devoted  much  attention  to  the  exami- 
nation of  the  blood  and  urine  in  this  disease. 

No.  1.  A  patient  affected  with  general  ana- 
sarca— Urine  copious,  clear,  pale,  coagulable 
by  heat  and  nitric  acid  :  specific  gravity  1*011. 
Blood  cupped  and  buffed,  serum  milky  :  spe- 
cific gravity  1*019. 

No.  2.  Man  aged  48,  anasarcous — Urine 
dingy  brown,  natural  in  quantity,  acid,  coagula- 
ble; specific  gravity  1*017,  contained  41  per 
cent,  of  albumen.  Serum  of  the  blood,  specific 
gravity  1-013. 

No.  3.  A  man  who  was  found  on  post-mor- 
tem examination  to  have  granulated  kidneys. 
Urine  reddish  brown,  very  scanty,  coagulable  ; 
specific  gravity  1*008.  Blood  cupped  and  buf- 
fed ;  specific  gravity  (of  the  whole  blood)  1-037. 

In  my  paper  on  the  blood  in  the  Medico- 
Chirurgical  Transactions,  vol.xvi.  I  have  stated 
the  case  of  a  woman  forty-eight  years  of  age,  who 
for  ten  weeks  had  complained  of  pains  in  her 
loins,  anasarcous  swelling  of  her  legs,  and  ge- 
neral debility,  and  who  passed  urine  which  was 
in  a  high  degree  coagulable.  I  examined  her 
blood,  and  found  it  to  contain  0*43  per  cent,  of 
fibrine,  and  only  1-61  per  cent,  of  albumen. 
The  specific  gravity  of  the  serum  was  1-020 
at  60°  Fahr.  In  that  paper  I  have  also 
observed  that  in  several  cases  marked  by 
coagulable  urine,  I  have  examined  the  specific 
gravity  of  serum  with  which  Dr.  Bright  has  fur- 
nished me,  and  have  always  found  it  much 
below  the  healthy  standard. 

It  is  not,   however,  in  this  complaint  ex- 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


clusively  that  the  albumen  of  the  blood  will 
be  found  deficient  in  proportion.  In  other 
dropsical  affections  it  will  sometimes  happen 
that  a  proportion  of  albumen  more  than  equi- 
valent to  the  tibrine  effused  will  disappear 
from  the  circulation.  Eleven  days  after  tap- 
ping a  young  woman,  in  whom  ascites  had 
supervened  upon  rheumatic  affection  of  the 
heart,  she  was  observed  to  be  filling  again  very 
fast.  A  few  ounces  of  blood  were  taken  from 
the  arm,  and  this  blood  was  found  to  contain 
0-319  per  cent,  of  fibrine,  and  only  3'51  per 
cent,  of  albumen.  Her  serum  had  a  specific 
gravity  of  1-023. 

The  experiments  of  MM.  Prevostand  Dumas 
(Annales  de  Chimie,  vol.  xxiii.)  which  have 
since  been  repeated  by  Gmelin  and  Tiedemann 
(PoggendorfTs  Annalen),  prove  satisfactorily 
that  urea  exists  in  the  blood  after  the  kidneys 
have  been  extirpated,  and  consequently  that  it 
is  not  formed,  but  merely  abstracted  by  those 
organs.  So  long,  however,  as  the  kidneys  act, 
we  cannot  expect  to  find  it,  since  it  is  removed 
from  the  circulation  as  fast  as  it  is  formed,  and 
never  exists  in  any  considerable  quantity. 

In  these  cases  of  diseased  kidney  a  result 
analogous  to  that  which  follows  extirpation 
occurs,  for  while  that  organ  is  permitting  albu- 
men to  pass  through  it  unchanged,  the  urea 
which  it  should  separate  is  very  generally  if  not 
always  found  in  the  blood.  This  I  have  proved 
in  repeated  instances,  and  it  is  now  so  generally 
admitted  from  the  experiments  of  Prout,  Chris- 
tison,  and  others,  that  it  is  scarcely  worth  while 
to  cite  cases.  Dr.  Bright,  vol.  ii.  p.  447,  al- 
ludes to  several  specimens  of  serum  from 
patients  under  this  disease,  which  he  had  sent 
me  for  examination,  in  some  of  which  I  did, 
and  in  others  I  could  not  detect  urea.  In  one 
very  remarkable  instance  of  a  young  woman,  the 
albuminous  state  of  whose  urine  constantly 
existed  for  above  three  years,  the  urine  con- 
tained less  than  one-third  of  the  normal  pro- 
portion of  urea,  while  about  one  per  cent,  of 
albumen  supplied  the  deficiency.  The  serum 
of  the  blood  was,  as  I  have  already  remarked  to 
be  usual  in  this  disease,  of  very  low  specific 
gravity,  being  only  1-021.  The  quantity  of  al- 
bumen in  1000  grains  amounted,  after  careful 
drying,  to  only  50  grains  instead  of  78  (Le- 
canu's  healthy  standard),  and  it  contained  fully 
as  much  urea  as  the  urine  itself,  the  1000  grains 
yielding  nearly  15  grains  of  that  principle. 

It  may  not  be  out  of  place  here  to  observe, 
that  in  this  disease  not  only  does  the  blood  it- 
self contain  urea,  but  all  those  effusions  also 
which  are  formed  from  it,  and  which  take  place 
in  the  different  serous  cavities.  I  have  repeat- 
edly detected  urea  in  these  cases  in  the  serous 
effusion  into  the  ventricles  of  the  brain ;  and 
Dr.  Barlow  found  it  in  one  case,  1st,  in  abun- 
dance in  the  ventricles  of  the  brain  ;  2dly, 
scantily  in  the  effusion  into  the  pleura  and  peri- 
cardium ;  and  3dly,  in  Abundance  in  the  peri- 
toneum. In  a  second  case  of  a  similar  nature 
urea  was  obtained  in  abundance  from  the  fluid 
of  the  pericardium.  In  a  third  the  effusion 
collected  after  death  from  the  pleura  of  a  man 
who  had  suffered  from  general  dropsy  and  raot- 


427 

tied  kidney,  yielded  a  very  satisfactory  specimen 
of  urea. 

I  have  dwelt  at  some  length  on  this  subject, 
as  it  is  only  of  late  years  that  the  attention  of 
the  medical  world  has  been  drawn  to  it  through 
the  writings  of  Dr.  Bright,  and  still  more  re- 
cently that  the  morbid  changes  presented  in  the 
blood  have  been  investigated. 

Didbetes. —  In  this  complaint  the  blood  un- 
questionably undergoes  some  material  change, 
although  its  nature  has  not  hitherto  been  very 
successfully  investigated.  This  may  be  inferred 
from  the  great  length  of  time  during  which  it  is 
capable  of  resisting  putrefaction,  a  circumstance 
first  noticed  by  Rollo,  and  which,  though 
doubted  by  some  authors,  I  have  had  oppor- 
tunities of  confirming  in  several  instances. 
Nicolas  and  Gieudeville*  have  observed  that  it 
contains  an  increase  of  serum  and  very  little 
fibrine,  but  this  is  not  borne  out  by  my  own 
experience  as  deduced  from  many  specimens  of 
diabetic  blood  which  I  have  examined;  neither 
can  its  antiseptic  qualities  be  attributed  to  any 
deficiency  in  the  proportion  of  azote,  for  Dr. 
Prout,  who  has  made  accurate  experiments  to 
determine  this  point,  has  found  it  not  to  differ 
in  this  respect  from  the  standard  of  health. 
The  most  eminent  chemists  both  abroad  and  in 
this  country  have  endeavoured  in  vain  to  de- 
tect sugar  in  diabetic  blood.  Dr.  Wollaston 
ascertained  that  the  smallest  portion  of  saccha- 
rine matter  added  to  serum  previously  to  its 
coagulation  by  heat,  prevents  the  subsequent 
crystallization  of  the  salts  it  contains,  yet  that 
in  diabetic  serum  those  salts  crystallized  with 
the  same  facility  as  in  that  procured  from  a 
person  in  health.  The  same  reasoning  as  that 
which  has  been  adduced  to  prove  that  urea  may 
be  formed  in  the  blood,  although  it  is  not  to  be 
detected  there  while  the  kidneys  perform  their 
office,  will  also  apply  to  the  existence  of  sugar 
in  the  blood  of  those  affected  with  this  disease. 
I  am  not  aware  that  the  arterial  blood  has  been 
made  the  subject  of  experiment,  and  yet  it  is 
possible  that  it  might  exist  in  the  arteries  alone, 
for  we  have  only  to  suppose  it  to  enter  the  cir- 
culation with  the  chyle,  and  after  having  been 
carried  through  the  lungs,  the  left  cavities  of  the 
heart,  and  the  aorta,  to  be  again  withdrawn  from 
the  circulation  by  the  kidneys.  I  do  not  pre- 
tend, however,  that  this  supposition  carries  with 
it  any  degree  of  probability. 

Cholera. — There  is  no  disease  in  which  the 
blood  undergoes  more  remarkable  changes  than 
in  malignant  cholera;  not  indeed  in  the  in- 
cipient stage,  as  affirmed  by  Dr.  Stevens,  but  in 
direct  proportion  to  the  intensity  and  duration 
of  the  collapse.  In  appearance  it  is  thick  and 
dark,  bearing  a  strong  resemblance  to  treacle  or 
tar.  It  is  of  high  specific  gravity,  the  serum 
varying  from  1-040  to  1-045  at  60  Fahr.;  and 
according  to  M.  Lecanu,  the  solid  matter  which 
it  contains  is  sometimes  double  that  of  the 
healthy  proportion.  Most  of  its  physical  cha- 
racters are  satisfactorily  accounted  for  by  its 
analysis,  which  has  been  accurately  made  by 
several  eminent  chemists,  among  whom  we  may 

*  Annales  de  Chimie,  vol.  xliv.  p.  69. 


BLOOD,  MORBID  CONDITIONS  OF  THE. 


423 

mention  Dr.  Turner,  M.  Lecanu,  and  Dr. 
O'Shaughnessy.  Cholera  blood,  according  to 
these  authorities,  contains  less  water  and  more 
albumen  and  haematosine  than  healthy  blood, 
and  its  salts  are  in  unusually  small  quantity,  or 
almost  entirely  wanting.  Dr.  O'Shaughnessy, 
who  has  detected  urea  in  cholera  blood,  states 
that  the  summary  of  his  experiments  denotes  a 
great  but  variable  deficiency  of  water  in  the 
blood  of  four  malignant  cholera  cases ;  a  total 
absence  of  carbonate  of  soda  in  two  ;  its  occur- 
rence in  an  almost  infinitessimally  small  propor- 
tion in  one ;  and  a  remarkable  diminution  of 
the  other  saline  ingredients  :  lastly,  the  micro- 
scopic structure  of  the  blood  and  its  capability 
of  aeration  are;  shewn  to  be  preserved.  The 
cause  of  the  dark  colour  of  the  blood  in  cholera 
is  a  point  which  we  are  told  by  Dr.  Turner  is 
by  no  means  decided.  Dr.  Thomson  and  Dr. 
O'Shaughnessy  are  at  variance  on  the  question 
of  its  susceptibility  of  arterialization.  Dr. 
Stevens  rather  unphilosophically  makes  its 
dark  colour  to  depend  primarily  on  the  poi- 
sonous cause  of  contagion,  yet  attributes  it  also 
to  a  deficiency  in  the  proportion  of  saline 
matter.  It  is  probably  not  owing  to  either  of 
these  causes,  but  to  a  defective  circulation 
through  the  lungs,  from  which  the  blue  livid 
tint  frequently  observed  over  the  surface  of  the 
limbs  likewise  originates.  The  corresponding 
diminution  of  animal  heat  gives  countenance  to 
this  supposition. 

Chlorosis, — Among  other  changes  which  oc- 
cur in  the  progress  of  chlorosis,  there  is  none 
more  constant  than  an  impoverished  condition 
of  the  blood,  which  is  thin,  light-coloured,  and 
weakly  coagulable,  being  deficient  in  fibrine,  and 
still  more  so  in  the  proportion  of  the  red  par- 
ticles. To  the  latter  cause  is  to  be  attributed 
the  diminished  temperature  of  the  surface,  to- 
gether with  the  universal  pallor  and  waxy  ap- 
pearance which  those  who  are  the  subjects  of 
this  disease  generally  exhibit.  The  deficiency 
of  colour  in  the  catamenia,  and  the  pale  stain 
which  haemorrhages  from  the  nose  leave  on 
linen,  are  also  referable  to  the  same  cause. 
In  aggravated  cases,  if  blood  be  drawn  from  the 
arm,  the  crassamentum  is  observed  to  be  of  a 
pale  rose  colour,  and  small  in  proportion  to  the 
serum.  We  have  to  regret  that  in  this,  as  in 
most  other  cases  of  morbid  blood,  pathologists 
have  contented  themselves  with  a  general  ob- 
servation of  facts  without  attempting  to  inves- 
tigate them  with  that  degree  of  precision  which 
can  alone  lead  to  a  further  advancement  of  our 
knowledge  respecting  their  causes.  The  only 
analyses  of  chlorotic  blood  of  which  I  can  find 
a  record  are  given  by  Mr.  Jenkins  in  two  well- 
marked  cases  of  chlorosis ;  the  one  of  a  girl 
aged  fifteen,  the  other  of  a  young  woman  aged 
twenty-one.  In  these  the  blood  contained  871 
and  852  parts  in  a  thousand,  of  water,  respec- 
tively, instead  of  780,  the  healthy  standard ;  and 
the  colouring  matter  amounted  to  48' 7  and  52, 
instead  of  133.  The  albumen  and  salts  were  in 
the  usual  proportions. 

Melanosis. — Although  it  would  be  foreign  to 
my  present  object  to  treat  of  the  various  morbid 
products  which  may  be  supposed  to  have  their 


origin  in  a  diseased  state  of  the  blood,  yet 
there  is  one  which  seems  so  evidently  to  be  the 
result  of  an  accidental  change  in  that  fluid,  that 
it  must  not  be   passed  over  without  a  brief 
notice.   The  similarity  of  chemical  composition 
in  the  blood  and  in  the  matter  of  melanosis  is 
such  as  to  leave  little  doubt  that  the  material 
of  which  the  latter  is  composed  has  its  origin 
in  the  circulation,  and  is  afterwards  deposited 
in  the  various  parts  in  which  it  is  found.     The 
different  analyses  of  melanosis,  says  Andral, 
all  concur  in  one  important  point.    They  all 
shew  that  the  accidental    production    called 
melanosis  is  formed  of  the  different  elements 
of  blood,  and  especially  of  a  colouring  matter 
which  more  or  less  resembles  that  of  the  blood, 
but  which  is,  nevertheless,  not  identical  with 
it.     M.  Foy,  in  his  analysis,  calls  this  altered 
cruor.     Dr.  Carswell,  to  whom  we  owe  the 
most  detailed  and  best  account  of  melanosis 
which  we  possess,  states  that  he  has  fixed  its 
seat  in  the  blood,  not  only  because  it  is  seen 
there,  but  because  his  anatomical  researches 
shew  that  it  is  there   formed.     He  makes  a 
grand  division   of    melanosis    into   true    and 
spurious;    the  former  of  which    occasionally 
makes  its  appearance  in  the  circulating  system, 
a   fact  which   is   well   established,   while  the 
latter  is  more  decidedly  the  result  of  chemical 
action.      Whenever  healthy  blood   comes   in 
contact  with  an  acid,  whether  in  or  out  of  the 
body,  its  colour  changes  from  red  to  brown  or 
black,  in  proportion  to  the  strength  and  abund- 
ance of  the  acid  employed.     It  is  to  this  cause 
that  we  are  to  attribute  the  appearance  of  brown 
or  black  ramifications,  patches,  or  points,  as  ob- 
served after  death  in  the  stomach  and  intestines. 
To  this  cause  also  are  owing  the  accumulations, 
during  life,  of  black  pitchy  matters  in  the  ali- 
mentary canal,  and  it  is  by  the  acidity  of  the 
black  vomit  and  its  power  of  reddening  litmus 
paper,  as  we  learn  from  Dr.  Stevens,  that  it 
can  alone  be  distinguished  from  blood  rendered 
black  by  defective  decarbonization  or  the  ab- 
sence of  saline  ingredients.     Where  a  haemor- 
rhage occurs,  whether  by  the  rupture  of  a  large 
vessel  or  by  a  general  oozing 'from  the  mucous 
membrane  into  the  stomach  or  bowels,  we  shall 
find  the  fluid  ejected  assume  the  appearance  of 
red  blood  or  of  brown  or  black  matter,  accord- 
ing to  the  presence  or  absence  of  the  gastric 
juice  in  an  acid  state.     Upon  this  almost  acci- 
dental circumstance,  then,  will  it  depend  whether 
we  are  to  designate  the  disease  haematemesis  or 
melaena,  there  being  in  reality  no  essential  dif- 
ference between  the  two  diseases.    The  black 
discolouration  of  blood  which  occurs  whenever 
it  becomes  stagnant  from  retarded  or  interrupted 
circulation,  will,  by  those  who  follow  the  views 
of  Dr.  Stevens,  be  attributed  to  a  similar  cause. 
According  to  that  author  it  is  the  presence  of 
carbonic  acid  which  acts  like  other  acids  in  ren- 
dering venous  blood  dark,  and  it  is  its  abstrac- 
tion by  oxygen  which,  combined  with  the  action 
of  the  saline  matters  it  contains,  restores  it  to 
its  scarlet  hue. 

The  foregoing  are  among  the  more  pro- 
minent diseases  in  which  the  blood  has  been 
observed  to  undergo  changes  either  directly 


BLOOD,  MORBID  CONDITIONS  OE  THE. 


cognizable  by  our  senses,  or  discoverable  by 
those  chemical  and  mechanical  means  which 
we  are  enabled  to  call  to  our  assistance.  There 
are,  however,  other  morbid  conditions  the  ex- 
istence of  which  is  equally  certain,  although 
their  essence  is  of  such  a  doubtful  nature  that 
it  defies  detection  by  the  coarse  instruments 
and  the  limited  skill  which  man,  in  the  present 
state  of  his  knowledge,  is  enabled  to  employ. 
In  the  exanthematous  diseases  the  blood  par- 
takes of  the  general  disorder  of  the  system.  Dr. 
Home  of  Edinburgh*  succeeded  in  reproducing 
measles  by  inoculation  with  blood  drawn  from 
a  superficial  vein  in  one  of  the  patches  of 
eruption  which  cover  the  skin  in  that  disorder; 
and  though  others  have  failed  in  this  experi- 
ment, it  has  been  successfully  and  often  re- 
peated by  Professor  Speranza  of  Mantua. 
Pregnant  females  affected  with  small-pox,  or 
even  exposed  to  its  virus,  though  they  may 
have  had  the  disease,  have  often  imparted  it  to 
the  foetus  in  utero,f  and  syphilis  has  been 
communicated  in  the  same  manner.  Professor 
Coleman  has  proved  by  experiment  that  the 
blood  of  a  glandered  horse  will  impart  glan- 
ders if  infused  into  the  veins  of  a  healthy 
animal.  Dupuy  and  Leuret  have  thus  pro- 
duced malignant  pustule ;  transfusion  of  the 
blood  of  a  mangy  dog  has  produced  mange  in 
another;  and,  according  to  Dr.  Hertwich  of 
Berlin,  the  blood  of  a  rabid  animal  will  by  inocu- 
lation communicate  the  disease.  A  remarkable 
instance  is  related  by  Duhamel,  in  which  a 
butcher  became  affected  with  a  malignant  pus- 
tular disease  in  consequence  of  having  put  into 
his  mouth  the  knife  with  which  he  had  slaugh- 
tered an  over-driven  ox.  Another  individual 
lost  his  life  from  sphacelus  of  the  arm  in  con- 
sequence of  a  wound  in  the  palm  of  his  hand, 
accidentally  inflicted  by  a  bone  of  the  same 
animal;  and  in  two  women  who  received  some 
drops  of  its  blood,  the  one  on  her  hand,  the 
other  on  her  check,  inflammations  ensued  which 
rapidly  terminated  in  gangrene. 

Although  in  all  these  instances  there  can  be 
no  doubt  that  the  blood  was  in  a  poisonous 
state,  there  is  no  reason  to  suppose  that  this 
could  have  been  foretold  by  any  thing  remark- 
able in  its  appearance  or  sensible  qualities. 
Scarcely  more  successful  in  general  has  been 
the  search  for  extraneous  poisons,  which  never- 
theless have  appeared  from  collateral  circum- 
stances to  have  entered  the  circulation,  or  have 
even  been  purposely  introduced  into  it.  Dr.Chris- 
tisonj  has  cited  a  sufficient  number  of  cases 
where  poisons  swallowed  have  been  afterwards 
found  in  the  blood,  to  shew  that  we  must  not 
infer  their  absence  from  our  inability  in  most 
cases  to  abstract  them  in  a  separate  form ;  and 
he  further  demonstrates  how  erroneous  such  an 
inference  might  be  by  stating  that  Dr.  Coindet 
and  himself,  after  destroying  a  dog  in  thirty 
seconds  by  injecting  8£  grains  of  oxalic  acid 
into  the  femoral  vein,  endeavoured  in  vain  to 

*  Duncan's  Medical  Commentaries,  vol.  xix. 
p.  213. 

t  Edinb.  Med.  and  Surg.  Journ.  for  April  1807. 
Med.-Chir.  Trans,  vol.  i.  p.  272. 

$  Christison  on  Poisons,  p.  14. 


429 

detect  any  portion  of  it  in  the  blood  of  the  iliac 
vein  and  vena  cava  collected  immediately  after 
death,  although  it  is  highly  improbable  that  it 
could  have  passed  oft'  by  any  of  the  secretions 
in  so  short  a  time. 

The  chief  obstacles  by  which  we  are  opposed 
in  such  researches  are  minuteness  of  quantity 
and  decomposition.  When  only  a  few  grains 
of  a  poison  are  absorbed,  and  thence  diffused 
not  only  through  the  whole  mass  of  circulating 
blood,  but  likewise  among  all  the  various 
tissues  and  solids  of  the  body,  being  moreover 
carried  off  by  the  kidneys,  perhaps  nearly  as 
fast  as  they  enter  by  the  circulation,  it  cannot 
be  matter  of  surprise,  however  delicate  our 
tests  may  be,  that  they  are  seldom  to  be  met 
with  even  where  still  retaining  their  chemical 
characters.  When  we  consider,  however,  that 
reagents  which  produce  a  change  of  properties 
in  those  bodies  with  which  they  are  brought  in 
contact  do  probably  themselves  undergo  a  cor- 
responding change,  we  shall  readily  perceive 
that  our  difficulties  will  be  still  further  in- 
creased on  this  account. 

The  products  of  diseased  action,  and  espe- 
cially pus,  have  been  often  met  with,  as  well  in 
the  arteries  and  veins,  as  in  the  cavities  of  the 
heart ;  but  it  yet  remains  a  matter  of  doubt 
whether  these  are  actually  formed  in  the  blood, 
or  whether,  as  seems  to  me  more  probable, 
they  are  not  rather  carried  into  the  circulation 
from  other  parts  in  a  degenerate  or  diseased 
state,  or  are  the  products  of  inflammation  in 
the  lining  membrane  of  the  bloodvessels  them- 
selves. 

With  respect  to  those  cases  where  worms 
and  insects  are  said  to  have  appeared  in  the 
blood,  whereof  many  are  recorded,  some  are 
referrible  to  the  head  of  false  polypi,  the  shape 
of  which  has  misled  the  observer,  others  to 
deception  or  the  accidental  presence  of  insects 
or  their  ova  in  the  receiving  vessel ;  and  though 
we  cannot  deny  the  possibility  that  parasitical 
animals  may  exist  in  the  fluids  as  well  as  in  the 
closed  cavities  and  solids  of  the  body,  yet  we 
require  better  evidence  than  has  yet  been  ad- 
duced to  confirm  our  belief  in  the  existence  of 
entozoa  in  the  circulating  current.  In  a  recent 
case  brought  forward  by  Mr.  Bushnan,*  and 
learnedly  illustrated  by  that  gentleman,  it 
would,  I  confess,  have  carried  more  conviction 
to  my  mind,  had  he  himself  watched  the  blood 
from  the  moment  of  its  quitting  the  vein  until 
the  larvae  which  he  describes  were  seen  swim- 
ming in  its  serum.  In  such  extraordinary  cases 
the  mind  is  not  satisfied  with  anything  short 
of  moral  certainty. 

From  what  has  been  set  forth  in  the  fore- 
going pages,  it  will  be  perceived  that  our 
knowledge  on  the  subject  discussed  in  them 
yet  remains  extremely  defective.  We  learn, 
indeed,  that  under  the  existence  of  disease 
the  different  constituents  of  the  blood  are 
liable  to  morbid  increase  or  diminution  as  well 
as  to  certain  alterations  in  their  sensible  qua- 
lities, hitherto  less  accurately  examined;  that 

*  History  of  a  case  in  which  animals  were  found 
in  blood,  &c. 


430 


BONE,  NORMAL  ANATOMY. 


there  are  instances  in  which  principles  not 
usually  met  with  in  the  healthy  circulation  may 
be  detected  in  it,  and  others  where  those  which 
are  always  present  in  a  state  of  health  do  nearly 
if  not  altogether  disappear.  But  that  which 
still  remains  unknown,  and  to  which  it  is  of 
the  highest  interest  and  importance  that  our 
investigations  should  be  directed,  is  the  con- 
nexion that  these  morbid  changes  have  with  the 
diseases  which  they  accompany ;  the  position 
which  they  occupy  in  the  relation  between  cause 
and  effect.  Perhaps  our  present  information 
is  not  sufficiently  minute  to  give  fair  expecta- 
tions of  any  considerable  advances  being  made 
in  this  line  of  inquiry ;  for  when  we  contemplate 
the  variety  of  materials  for  the  formation  and 
removal  of  morbid  as  well  as  of  healthy  secre- 
tions and  structures,  which  are  stealing  unper- 
ceived  along  the  vital  current,  we  are  forced  to 
confess  how  small  is  the  sum  of  all  we  know 
compared  with  that  of  which  we  are  still  igno- 
rant, and  how  ample  is  the  harvest  which  yet 
remains  to  be  gathered  by  future  labourers  in 
this  field  of  research. 

BIBLIOGRAPHY.— (The  following  comprehends  the 
most  esteemed  writings  on  the  blood  in  its  healthy  as 
well  as  its  morbid  states.)— R.  Boyle,  Mem.  for  a 
nat.  hist,  of  human  blood,  8vo.  Lund.  1684,  and 
Analytical  observ.  on  milk  found  in  veins  instead 
of  blood,  Phil.  Trans.  1665.  Albinus,  De  Mass® 
Sanguinis  corpusculis,  4to.  1688  (Recus.  in  Bailor 
Disp.  Anat.  t.  ii.)  ;  Ejus,  De  Pravitate  Sanguinis, 
4to.  Franc.  1689.  De  Sandra,  De  naturali  et  praeter- 
naturali  sanguinis  statu,  4to.  Bon.  1696.  De  Haen, 
De  sanguine  humana,  in  Ej.  Ratione  medendi. 
N.  Davies,  Exper.  to  promote  the  analysis  of  the 
blood,  8vo.  Lond.  1760.  Fontana,  Nuove  osserv. 
sopra  i  globetti  rossi  del  sangae,  8vo.  Lucca,  1768. 
Hcwson,  Exper.  inquiry  into  the  properties  of  the 
blood,  8vo.  Lend.  1771-78.  Spallanzani,  Fenomeni 
della  circolazione,  8vo.  Moden.  1773  :  Anglice  by 
Hall,  Lond.  1801.  Holler,  El.  Physiol.  t.  ii. 
Bordeu,  Analyse  Med.  du  sang,  Par.  1771.  Thou- 
vetiel,  Mem.  sur  le  mechanisme  et  les  produits  de  la 
sanguification,  Mem.  de  1'Acad*  de  St.  Petersbourg, 
an.  1776.  Delia  Torre,  Oss.  microscopiche,  4to. 
Neap.  1776.  Hey,  Observations  on  the  blood,  8vo. 
Lond.  1779.  Blumenbach,  De  vi  vitali  sanguinis 
deneganda,  4to.  Gotting.  1788.  Deyeux  fy  Par- 
mentier,  Mem.  sur  les  alterations  du  sang,  4to.  Par. 
1797.  Hunter  on  the  blood,  &c.  1794.  Wells  on 
the  colour  of  the  blood,  Phil.  Trans.  1797.  Kreysig, 
De  sanguine  vita  destitute,  Prag.  4to.  1798.  Tollard, 
Diss.  sur  la  fibrine,  4to.  Strasb.  1803.  Le  Gallois, 
Le  sang  est  il  identique  dans  tous  les  vaisseaux, 
8vo.  Par.  1805.  Henke,  Uber  die  vitalit'at  des 
Blutes,  8vo.  Berl.  1806.  Bostock,  Med.-Chir.  Trans, 
vol.  i.  Dowler  on  the  products  of  inflammation,  Mt  d. 
Chir.  Trans,  vol.  xii.  Thachrah  on  the  properties 
of  the  blood,  8vo.  Lond.  1819.  Wilson>  Lecture* 
on  the  blood,  &c.  Lond.  1819.  Kolk,  Sanguinis 
cnagulantis  historia,  &c.  Diss.  Inaug.  Groning. 
1820.  Cotte,  Sur  les  diff.  caracteres  du  sang  dans 
Tetat  de  sante  et  de  maladie,  8vo.  Aix,  1821.  Davy 
on  the  buffy  coat,  Phil.  Trans.  1822.  Krimer, 
Versuch  einer  Physiol.  des  Blutes,  8vo.  Leipz.  1823. 
Stoker,  in  Pathological  Observations,  Dublin,  1823. 
Scudamore,  Essay  on  the  blood,  Lond.  1824.  Mi- 
chaelis,  De  partitms  constitutivis  sing,  partium  sang, 
art.  et  ven.  8vo.  Berol.  1827.  Babinyton  on  fatty 
matter  in  the  blood,  Med.-Chir.  Trans,  vol.  xvi. 
Christison  in  Ed.  Med.  and  Surg.  Journal,  No.  ciii. 
Velpeau,  Recherches  sur  les  alterations  du  sang, 
8vo.  Par.  1826.  Trousseaux,  in  Arch.  Gen.  de 
Med.  t.  xiv.  Sec/alas,  in  ibid,  t.  xii.  Gendrin, 
Recherches  sur  les  fievres,  and  Hist.  anat.  des 
inflammations.  Andral,  Pathological  anatomy, 


by  Townsend.  Denis,  Rech.  exper.  sur  le  sang 
hum.  1830.  Stevens  on  the  blood,  8vo.  Lond.  1832. 
O'S/iaughnessy,  Report  on  the  chemical  pathology 
of  cholera,  Lond.  1832.  Prevost  Of  Dumas,  Examen 
du  sang,  &c.  Bibliotheq.  Univ.  de  Genev.  t.  xvii. 
See  also  Rudolphi,  Blumenbach,  Sprengel,  Adelon, 
&c.  in  their  systems  of  physiology. 

(  B.  G.  Babington.) 

BONE,(general  anatomy  in  the  normal  state.) 
Gr.  oa-reov.  Lat.  os.  Fr.  os.  Germ.  derKnochen. 
Ital.  osso.  The  important  offices  fulfilled  by 
bone  in  the  animal  economy,  and  its  almost 
imperishable  nature,  could  not  but  give  it  im- 
portance in  the  eyes  of  the  philosopher ;  whilst 
every  language  bears  testimony  to  the  high 
place  it  holds  in  popular  estimation.  We  see 
it  forming  a  framework  to  give  shape  and  sup- 
port to  the  body,  cases  and  cages  to  protect 
the  more  delicate  organs,  levers  by  which  loco- 
motion is  performed  and  force  exerted.  Again, 
we  find  it,  among  the  tombs,  successfully  resist- 
ing those  destructive  agents  which  a  century 
before  reduced  the  softer  portions  of  the  body 
to  dust;  and  we  speak  of  laying  our  bones  in 
the  grave  as  if  they  constituted  the  essential 
element  of  our  frame. 

We  propose  to  treat  of  the  general  anatomy 
of  bone  under  the  following  heads,  viz. — 1.  its 
physical  properties  and  intimate  structure  in 
man  :  2.  its  periosteum  and  medulla,  and  its 
organization  as  a  part  of  the  living  system  :  3. 
its  chemical  composition :  4.  its  peculiarities 
in  other  animals. 

I.  The  physical  properties  and  intimate 
structure  of  bone  in  man. — The  most  remark- 
able property  in  bone,  and  that  which  first 
arrests  attention,  is  its  extreme  hardness  com- 
pared with  other  parts  of  the  system.  It  is, 
indeed,  the  only  substance  in  the  body  which 
deserves  to  be  called  hard ;  all  others  are  more 
or  less  soft,  and  are  consequently  destitute  of 
that  resistance  and  firmness  by  which  bones 
are  so  admirably  adapted  for  the  offices  they 
have  to  fulfil  in  the  animal  machine.  The 
hardness  usually  increases  with  age.  It  varies 
a  little  in  different  situations,  and  depends,  as 
we  shall  see,  on  the  earthy  matter  which  enters 
largely  into  the  composition  of  the  bones. 

The  colour  of  bone  in  the  living  person  is 
a  pale-rose  colour,  inclining,  in  early  life  to 
red,  in  old  age  to  a  yellowish  white.  Bones 
assume  a  beautiful  white  when  macerated  and 
deprived  of  the  oily  and  sanguineous  fluids 
which  pervade  them.  The  specific  gravity  of 
fresh  bone  is  greater  than  that  of  any  other 
animal  substance.  Bone  is  opaque  or  only 
slightly  diaphanous.  Bones  are  flexible  and 
elastic.  We  find  that  the  ribs  may  be  bent 
and  afterwards  recover  their  form  perfectly; 
every  schoolboy,  indeed,  knows  the  value  of 
a  horse's  rib  as  a  bow.  This  elasticity  frequently 
saves  them  from  fractures,  and  lessens  the  shock 
which  would  otherwise  be  communicated 
to  the  nervous  centres  and  delicate  structures 
they  defend.  It  is  possessed  by  every  bone, 
and  may  be  demonstrated  in  the  oldest  and 
most  rigid  by  cutting  them  into  thin  slices. 

Shape. — Bones  assume  every  variety  of  shape, 
as  might  be  expected  from  the  use  made  of 


BONE,  NORMAL  ANATOMY. 


431 


them  in  so  complicated  a  piece  of  machinery 
as  the  skeleton.  These  varieties  have  been 
reduced  by  anatomists  to  four  classes,  viz.  1. 
the  long  or  cylindrical ;  2.  the  broad  or  Jlat ; 
3.  the  short  or  thick ;  and  4.  the  mixed  or  irre- 
gular bones.  The  long  bones  are  distinguished 
by  their  length,  which  greatly  exceeds  their 
other  dimensions.  They  are  to  be  found  only 
in  the  extremities,  and  are  adapted  for  locomo- 
tion and  for  supporting  the  weight  of  the  body. 
They  are  never  exactly  cylindrical,  being  al- 
ways contracted  in  the  middle  or  shaj't,  and 
enlarged  at  each  end ;  and  their  transverse  sec- 
tion is  oval  or  triangular,  never  round.  The 
broad  or  Jlat  bones  are  thin,  generally  arched, 
and  fitted  to  protect  delicate  organs;  we  find 
the  best  specimens  of  them  in  the  cranium. 
The  short  have  nearly  equal  length,  breadth, 
and  thickness ;  they  are  seen  in  the  carpus  and 
tarsus.  The  ntiied  or  irregular  bones  are 
usually  classed  with  the  short,  but  it  is  more 
convenient  to  separate  them :  the  vertebrae  are 
good  examples  of  these.  The  ribs  and  bones 
of  the  pelvis  may  also  be  ranged  with  them, 
combining  the  characters  of  two  of  the  pre- 
ceding classes.  Each  of  these  divisions  exhibits 
certain  peculiarities  of  structure  to  which  we 
shall  allude  hereafter.* 

If  we  prepare  bones  by  careful  maceration 
and  drying,  and  then  saw  them  through,  or, 
what  is  better,  fracture  them  with  a  smart  blow 
of  a  hammer,  we  observe  the  density  of  texture 


to  differ  very  much  in  different  portions.  The 
outer  part  is  generally  much  more  dense  and 
close  than  the  interior,  and  is  called  the  com- 
pact 9  vitreous,  or  cortical  substance.  The  inte- 
rior, open  and  areolar  in  its  appearance,  is  the 
spongy,  cancellated,  or  reticular  substance. 
These  two  are  arranged  in  a  peculiar  manner 
in  each  class  of  bone.  In  the  long  there  is  a 
considerable  thickness  of  compact  substance  in 
the  shaft,  surrounding  a  cavity,  and  but  little 
of  the  spongy,  whilst  towards  the  ends  the 
compact  gradually  becomes  thin  as  paper,  the 
spongy  increasing  in  quantity  and  filling  up  all 
the  interior,  as  if  formed  by  the  expansion  of  the 
compact  tissue  (Jig.  186,  «).  In  the  Jlat  bones 
the  compact  substance  is  formed  into  two  plates 
with  a  thin  stratum  of  spongy  substance  called 
the  diplue  between  (Jig.  186,  6).  In  very  thin 
bones  the  diploe  is  often  absent.  The  short 
bones  are  spongy  throughout,  with  a  thin  layer 
of  the  compact  tissue  on  the  surface ;  they  are 
like  the  extremities  of  the  long  bones:  and  the 
irregular,  resembling  in  shape  two  or  more  of 
the  former  classes,  have  a  corresponding  arrange- 
ment of  the  two  tissues. 

A  vertical  section  of  three  long  bones  is  re- 
presented at  Jig.  186,  where  A  is  the  head  and 
neck  of  the  femur,  and  B  the  upper  extremities 
of  the  tibia  and  fibula :  a  indicates  the  com- 
pact tissue ;  6  the  reticular ;  at  c  it  may  be  seen 
how  thin  is  the  layer  of  compact  tissue  cover- 
ing the  head  of  the  femur. 


Fig.  186. 


In  the  shaft  of  the  long  bones  there  exists  a 
cavity  of  considerable  size  filled  with  marrow, 
and  called  the  medullary  cavity.  This  is  widest 
in  the  centre,  gradually  getting  smaller  towards 

*  See  fun  her  particulars  respecting  foramina, 
processes,  epiphyses,  &c.  as  connected  with  mecha- 
nical contrivance,  under  the  article  SKELETON. 


the  extremities,  where  its  place  is  occupied  with 
spongy  substance.  The  interior  of  this  cavity 
is  rough ;  bony  processes  project  into  it,  and 
form  a  kind  of  net-work  resembling  the  spongy 
substance  at  the  ends,  but  with  more  open  and 
less  regular  cells.  By  some  anatomists  the 
term  xpongy  is  confined  to  the  cellular  arrange- 
ment at  the  ends,  that  in  the  middle  being 


432 

denominated  reticular  or  cancellated.  Such  a 
distinction  is  useless.  There  is  no  line  of 
demarcation  between  them. 

At  first  view  a  great  difference  appears  to" 
exist  between  the  compact  and  the  spongy 
substance,  but  in  reality  this  is  not  the  case. 
The  degree  of  condensation  is  the  only  dis- 
tinction. The  spongy  substance  would  become 
compact  were  the  sides  of  its  cells  pressed 
together,  and  the  compact  would  become  spongy 
or  reticular  were  its  texture  loosened  by  en- 
larging the  minute  cells  which  may  be  detected 
even  in  it.  Such  changes  actually  occur  by 
the  processes  of  absorption  and  deposition  in 
growing  bones.  In  the  perfect  bone  the  cells 
are  compressed  towards  its  middle  to  diminish 
its  bulk,  and  thereby  to  accommodate  the  bel- 
lies of  the  muscles ;  and  they  are  expanded  at 
its  ends  for  the  purpose  of  giving  security  to 
the  joints  by  a  more  extensive  surface,  and 
allowing  more  room  and  power  to  tendons,  &c., 
whilst  the  osseous  matter  in  equal  lengths  of 
bone,  whether  at  centre  or  extremity,  is  of  nearly 
equal  weight.  The  surface  of  bone  in  many 
places  presents  a  striated  appearance;  and  small 
holes  or  canals  are  seen  on  it  especially  near 
the  ends  of  long  bones. 

Simple  inspection  of  dried  and  divided  bone 
carries  us  thus  far  in  the  knowledge  of  its 
structure.  But  the  question  still  arises,  what 
is  the  arrangement  of  the  particles  which  com- 
pose the  compact  and  spongy  tissues  ?  Is 
bone  laminated,  or  fibrous,  or  cellular?  or 
does  it  partake  of  a  texture  in  which  these 
three  varieties  of  disposition  are  to  be  found  ? 
One  might  imagine  there  could  be  no  great 
difficulty  in  answering  these  questions,  where 
bone  is  so  readily  procured,  so  easily  pre- 
served, and  admits  of  such  varied  modes  of 
examination.  It  can  be  viewed  in  the  living 
subject,  or  after  death  while  fresh,  or  when 
prepared  by  injection,  or  when  all  its  moisture 
is  removed.  It  was  long  ago  discovered  to 
consist  of  an  earthy  and  an  animal  portion, 
either  of  which  can  be  removed,  leaving  the 
other  undisturbed  in  its  original  form.  Yet, 
with  all  these  "  appliances  and  means  to  boot," 
anatomists  have  entertained  opposite  opinions, 
and  are  not  yet  quite  agreed  upon  the  subject. 
Malpighi,  the  first  author  who  deserves  to  be 
mentioned,  thought  that  bone  consisted  of 
fibres  and  filaments  with  an  intermediate  os- 
seous juice  :  "  constat  igitur,  ossa  coagmentari 
filamentis,  et  fibris  per  longum  ductis  in  rete 
implicitis,  quae  aflfuso  osseo  succo  ferrurni- 
nantur  in  solidam  densamque  ossis  naturam." 
(Op.  Posth.  p.  47.  Lond.  1636.)  He  also 
allowed  the  existence  of  lamellae,  though  he 
does  not  put  forward  its  lamellar  structure  in  a 
prominent  way.*  Gagliardi  adopted  his  no- 


BONE,  NORMAL  ANATOMY. 


pighi 
Coul 


*  We  are  told  by  an  interesting  writer  that  Mal- 
i  compared  these  lamellae  to  the  leaves  of  a  book. 
this  writer  have  taken  "  libri,"  in  the  fol- 
lowing passage,  to  mean  book  instead  of  bark,  of 
which  last  Malpighi  had  just  been  speaking  ? 
"  Pari  incremento  procedit  natura  in  ossium  aug- 
mento.  Foetus  ossa,  et  cranium  precipue,  fila- 
mentorum  progressum  exhibent ;  haec  non  omnino 
sibi  parallela  sunt,  et  hinc  inde  breves  appendi- 


tions  of  a  laminated  structure,  but  made 
additions,  from  which  Malpighi,  at  a  subse- 
quent period,  expressed  his  dissent.  He  exa- 
mined bones  long  exposed  to  the  weather,  or 
softened  by  boiling,  and  concluded  that  they 
were  formed  of  plates,  (lamellae,  squamulae, 
bracteae,)  held  together  by  processes,  in  the 
form  of  nails,  the  shape  and  direction  of  which 
he  minutely  describes.*  Clopton  Havers  found 
bones  composed  of  plates  connected  by  an 
osseous  juice,  with  pores  which  ran,  some 
transversely  through  the  plates,  others  longitu- 
dinally through  the  entire  length  of  the  bone.f 
Leuwenhoeck  thought  that  the  filaments  of  Mal- 
pighi were  hollow  tubuli.J  Duhamel  observed 
concentric  layers  as  in  wood.§  Haller  says,  "  Fi- 
brosum  est  (os)  sive  in  laminas  et  fila  divisum 
quse  sulcis  separantur."||  And  Monro  lays  it 
down  that  "  bones  are  composed  of  a  great 
many  plates,  each  of  which  is  made  up  of 
fibres  or  strings  united  by  smaller  fibrils."1T 
About  the  close  of  the  eighteenth  century  the 
celebrated  Scarpa  published  his  work  "  De 
penitiori  ossium  structura,"  in  which  he  com- 
bats former  opinions,  and  asserts  that  bone  is 
in  every  part  of  a  cellular  or  reticular  texture. 
In  the  first  place  he  shows  that  we  have  no 
proof  of  its  lamellated  structure ;  the  appear- 
ances produced  by  calcination,  the  weather, 
disease,  &c.  on  which  former  anatomists  relied, 
proving  nothing.  Calcination  is  a  rude  pro- 
cess, and  acts  with  different  power  on  the  dif- 
ferent parts  :of  the  same  bone  as  they  vary  in 
density,  and  divides  them  irregularly  as  it 
happens  to  overcome  their  force  of  cohesion. 
The  same  thing  may  be  said  of  the  weather. 
And  exfoliation  takes  place  in  the  skin,  whose 

culas  filamentosas  promunt,  quibus  invicem  col- 
ligata  rete  efformant  parum  a  libri  natura  distant, 
cujus  potiores  areae  et  tota  fibrarum  compages 
exsudante  osseo  succo  repletur  et  tumet." 
Here  we  have  a  tissue  of  fibres  and  filaments  run- 
ning in  various  directions,  and  forming  a  net-work 
not  unlike  a  book  ! !  From  this  quotation,  indeed,  it 
might  be  thought  that  our  author  entirely  denied 
the  existence  of  plates.  However,  in  the  next 
sentence  he  speaks  of  plana,  lamellae,  and  bractete  : 
(t  Successivis  incrernentis  nova  fibrarum  plana  su- 
perinducuntur,  quae  praeexistenti  lamelleB  osseo 
agglutinata  succo,  debitam  molem  et  firmitatem 
excitant.  Patent  autem  singula  plana  resolutione 
facta  per  longum  ossium  maceratione ;  integrae 
namque  osseae  reticulares  bracteee  evelluntur. 
In  abortibus  vero  in  cranio  inchoatum  rete  evi- 
denter  conspicitur." — Anatome  Plantarum.  Op. 
Omn.  p.  19,  Lond.  1686. 

*  "  Natura  prudens  ossiculis  eas  transfixit." 
The  nails  were  of  four  kinds  for  the  outer  plates, 
viz.  "  pprpendiculares  acuti,  perpendiculares  ca- 
pitati,  oblique  situati,  et  inflexi  angulum  effor- 
mantes."  The  inner  plates,  forming  the  spongy 
substance,  differed  from  the  outer,  and  were  of 
three  kinds,  the  corrugated,  the  perforated  or  cri- 
briform, and  the  reticulated.  These  had  a  system 
of  nails  peculiar  to  them  :  "  alia  sine  cuspide, 
plurima  ramusculos  rescissos  efformant,  nonnulla 
breviora." — Anatome  Ossium.  Lugd.  Bat.  1723. 

t  Observationes  de  Ossibus,  Auctore  Cloptone 
Havers.  Amstel.  1731. 

t  Opera  Omnia,  Lugd.  Bat.  1722. 

§  Mem.  de  1'Academie  Roy.  des  Sciences,  1739, 
41,  42,  43.  , 

||  Opera  Minora,  torn.  ii.  Laus.  1767. 

f  Monro's  Works,  Edin.  1781. 


BLOOD,   NORMAL  ANATOMY. 


cellular  texture  no  one  denies.  In  the  next 
place  he  endeavours  to  establish  its  reticular 
texture;  1st,  by  observations  and  experiments 
on  the  bones  of  a  chick,  made  during  its 
growth;  2d,  by  treating  bones  with  dilute 
muriatic  acid,  and  then  putting  them  in  oil  of 
turpentine  to  render  them  transparent.  In  every 
bone,  he  says,  the  net- work  was  conspicuous. 
He  observed  the  same  in  rickets,  in  exostosis, 
and  in  callus;  and  still  more  remarkably  in  the 
bones  of  the  amphibia,  reptiles,  and  fishes.  The 
conclusion  at  which  Bichat  arrived  is  not  very 
different :  "  Ces  lames  osseuses  ne  me  paroissent 
point  exister  dans  la  nature."  "  Considerons 
le  tissu  compact  comme  un  assemblage  de 
fibres  rapprochees  mais  nullement  separees 
par  couche."*  Blumenbach  and  Meckel  in- 
cline to  the  lamellar  arrangement.  More  re- 
cently bone  has  been  submitted  to  microscopic 
examination  by  Mr.  Howship,  who  agrees  with 
Scarpa  that  the  ultimate  texture  of  bone  is  not 
lamellated  but  reticular.  He  coincides,  too, 
in  opinion  with  Havers  and  Leuwenhoeck  as  to 
the  existence  of  minute  longitudinal  canals  in 
it;  and  he  adds  that  the  canals  communicate 
freely  with  each  other,  and  that  a  fine  vascular 
membrane  lines  them  in  the  foetus,  where  they 
may  be  seen  projecting  into  the  temporary  car- 
tilage during  the  growth  of  bone  in  the  form 
of  fibres  which  are  tubular.f  Bostock  says, 
"  the  membrane  of  bone  is  composed  of  plates 
very  similar  in  their  general  form  to  those  of 
the  cellular  texture,  and  it  is  probable  that  the 
earthy  matter  is  inserted  between  these  plates, 
and  thus  is  likewise  disposed  to  assume  the 
laminated  structure."  And  again  :  "  As  we 
may  presume  that  the  earthy  part  of  the  bone 
is  moulded  into  its  appropriate  form  by  the 
membrane  into  which  it  is  deposited,  we  may 
judge  of  the  structure  of  the  latter  by  that  of 
the  former,  which,  from  its  firmer  consistence, 
it  is  more  easy  to  ascertain.  Now,  whether  we 
examine  bone  during  its  formation  in  the  foetal 
state,  or  after  it  has  had  its  membrane  destroyed 
by  the  action  of  fire,  we  find  the  earth  to 
assume  the  appearance  of  fibres,  which,  when 
the  bone  is  perfected,  have  a  tendency  to  a 
laminated  arrangement."}: 

It  is  plain,  from  the  quotations  we  have 
made  from  some  of  the  most  distinguished 
writers  on  the  structure  of  bone,  that  all  before 
the  time  of  Scarpa  considered  it  laminated,  or 
fibrous  and  laminated,  while  all,  after  his 
publication,  looked  upon  it  as  cellular.  In 
the  former,  however,  we  see  some  intimations 
of  a  reticular  texture ;  in  the  latter  we  hear  of 
a  tendency  or  a  disposition  to  a  laminated  ar- 
rangement. If,  with  these  opinions  before  us, 
we  come  to  examine  for  ourselves,  I  think  we 
shall  have  no  hesitation  in  agreeing  with  Scarpa 
that  it  is  cellular.  At  the  same  time  it  must 
be  confessed  that  the  sides  of  the  cells  are,  in 
the  compact  tissue,  so  pressed  together  that 
the  appearance  of  laminae  is  often  very  striking, 

*  Anat.  Gencr.   tome  iii.   pp.  24-6.     Par.  1812. 
f  Medico-Chirurgical  Trans,  vols.  vi.  and'vii. 
J   Rostock's  Elementary   System   of  Physiology, 
vol.  i. 
VOL.  I. 


433 

arid,  again,  that  the  sides  of  the  cells  have,  in 
most  places,  the  appearance  of  fibres.  When 
the  earthy  portion  is  removed  by  an  acid,  we 
-  can  teaze  out  the  membranous  portion  with  a 
pin,  and  almost  demonstrate  the  fibres.  But  a 
closer  examination  will  show  that  we  have  torn 
the  cells  and  destroyed  the  true  texture.  The 
laminated  disposition  supposed  to  be  shown  by 
exfoliation,  the  weather,  burning,  &c.  may  all 
be  proved  to  be  deceptive ;  and,  indeed,  there 
seldom  can  be  exhibited  a  plate,  however  small, 
of  equal  thickness  throughout,  which  has  been 
removed  by  any  of  these  agents.  There  is, 
however,  an  approach  to  the  laminated  ar- 
rangement, and  every  cell  is  formed  of  parti- 
cles which  approach  to  the  form  of  fibres.  The 
longitudinal  canals  of  Havers,  Leuwenhoeck, 
and  Howship,  probably  result  from  the  flattened 
cells,  and  may  be  deceptive  appearances  in 
the  old  bone,  or  the  channels  for  bloodvessels, 
&c. 

2.  The  periosteum  and  medulla,  and  the 
organization  of  bone  as  a  part  of  the  living 
system. 

A.  The  periosteum  is  a  fibrous  membrane 
of  a  dull  white  colour.  It  covers  bone  on 
every  part  of  its  circumference,  except  where 
enamel  takes  its  place  as  on  the  teeth,  or  car- 
tilage as  on  the  articular  extremities,  or  fibro- 
cartilage  as  where  tendons  play,  or  tendon  as 
on  sesamoid  bones.  The  fibres  which  compose 
it  run  in  different  directions  and  form  a  tissue 
of  great  strength.  On  the  long  bones  the 
greater  number  of  fibres  take  a  longitudinal 
direction.  The  superficial  ones  extend  for  a 
considerable  length  without  interruption;  the 
deep  are  short.  All  interlace  with  the  liga- 
ments of  the  articulations,  and  become  in- 
separably united  to  them,  but  there  is  not, 
as  was  formerly  imagined,  a  continuity  of 
fibres  from  one  bone  to  the  other  by  means  of 
the  ligaments;  on  the  contrary,  the  direction 
of  the  fibres  in  these  two  organs  seldom  co- 
incides. 

The  external  surface  of  the  periosteum  is  in 
contact  with  a  great  variety  of  parts :  muscles, 
synovial  bursae,  mucous  membranes,  vessels 
and  nerves,  rest  on  it  immediately,  or  are 
separated  from  it  by  cellular  tissue,  and  thus 
permitted  to  move  freely  on  it.  The  other 
surface  is  connected  to  the  bone  by  vessels, 
and  by  numerous  prolongations  which  pass 
into  the  osseous  substance  and  are  lost  there. 
This  connexion  is  weak  in  early  life,  and  espe- 
cially in  the  centre  of  the  long  bones;  but  in 
the  more  advanced  periods  the  deeper  sub- 
stance of  this  membrane  becomes  identified 
with  that  of  the  osseous  tissue;  thus  its  union 
is  rendered  more  intimate,  its  thickness  di- 
minished and  its  density  increased.  The  union 
is  so  close  in  old  age  and  even  in  middle  life, 
that  the  inner  fibres  of  the  periosteum  are  sup- 
posed to  be  the  seat  of  calcareous  deposition, 
and  to  be  converted  into  bone. 

The  vascularity  of  the  periosteum  may  be 
easily  shown  by  injection,  especially  in  the 
young.  Its  vessels  freely  anastomose  with 
those  of  the  surrounding  soft  parts,  and  there 
is  no  point  of  the  external  osseous  surface 

2  F 


434 


which  is  not  perforated  with  the  communi- 
cating branches.  Some  lymphatics  have  been 
discovered  in  its  tissue,  but  no  nerves ;  how- 
ever, the  diseases  to  which  it  is  subject, 
the  symptoms  to  which  these  give  rise, 
and  the  changes  that  follow,  leave  no  doubt 
of  the  existence  of  both.  That  cellular 
substance  enters  into  its  formation  is  inferred 
from  some  of  its  morbid  phenomena,  as  gra- 
nulation ;  and  independently  of  this  argument, 
on  which  we  do  not  lay  much  stress,  its  exter- 
nal fibres  are  evidently  of  a  mixed  nature,  com- 
bining common  cellular  membrane  with  its 
own  peculiar  substance.  The  proper  and 
essential  part  is  the  dense,  inelastic,  and  very 
resisting  fibre,  by  which  it  is  associated  with 
other  fibrous  membranes.  (See  FIBROUS 
TISSUE.)  The  older  anatomists  believed  that 
the  periosteum  had  its  origin  from  the  dura 
matei,  and  might  be  traced  as  one  continuous 
membrane  over  every  bone  in  the  body.  Boer- 
haave  asserts  (Praelectiones  Academicce)  that 
if  we  could  remove  it  without  rupture,  we 
should  have  an  exact  mould  of  the  skeleton 
with  all  the  joints.  Its  origin  from  the  dura 
mater  was  said  to  take  place  through  the  fora- 
mina which  transmitted  the  nerves ;  there  the 
dura  mater  separated  into  two  layers,  one  of 
which  enveloped  the  nerves  as  neurilema, 
the  other  the  bones  as  periosteum.  But  there 
does  not  appear,  on  close  inspection,  to  be  any 
actual  identity  between  the  dura  mater  and 
periosteum,  although  they  are  most  intimately 
connected ;  and  there  certainly  is  no  continuity 
of  the  latter  membrane  over  the  joints.  It  is 
true  that  we  may,  at  least  in  young  subjects, 
after  boiling,  tear  off  the  articular  ligaments 
with  the  periosteum,  but  the  tendons  come  off 
with  it  too  ;  and  in  both  cases  the  fibres  are 
seen  to  be  interlaced,  not  continuous. 

Various  uses  have  been  assigned  to  the  peri- 
osteum, such  as  modelling  the  bone  in  its 
growth  and  adding  new  layers  to  it,  for  the 
further  consideration  of  which  we  refer  to  the 
article  OSTEOGENY.  It  is,  moreover,  also  said 
to  be  useful  for  the  purpose  of  protecting  the 
bone  from  the  impression  of  surrounding 
muscles,  arteries,  &c.,  and  vice  versa,  shield- 
ing them  from  the  rough  and  unyielding 
osseous  substance ;  permitting  the  soft  parts  to 
move  freely  without  injury ;  and  serving  as  a 
centre  for  the  fibrous  system  in  general.  This 
last  is,  in  Bichat's  opinion,  a  most  important 
use;  he  considers  its  attachment  to  bone  is 
more  for  the  purpose  of  affording  a  paint 
cTappui  to  the  fibrous  system  than  for  any 
office  it  can  fulfil  with  regard  to  the  osseous 
system.* 

B.  Medulla  or  marrow. — When  a  longitu- 
dinal section  of  a  long  bone  is  made,  we  ob- 
serve a  large  tubular  cavity  occupying  the 
shaft,  becoming  smaller  as  we  recede  from  the 
centre,  and  replaced  in  the  extremities  by  the 
spongy  tissue.  This  tube  is  rounded,  not 
having  exactly  the  triangular  form  so  commonly 
presented  by  the  bone  externally.  Its  surface 
is  rough,  especially  near  the  ends,  as  if  it  had 

*  Anat.  Gen.  tome  iii.    Par.  1812. 


BONE,  NORMAL  ANATOMY. 


originally  contained  cells  which  were  in  some 
way  or  other  broken  up.  All  this  cavity  is 
filled  with  a  peculiar,  soft,  adipose  substance — 
the  medulla  (quasi  in  media),  contained  in  a 
membrane  of  extreme  delicacy. 

The  medullary  membrane,  or  internal  peri- 
osteum as  it  is  often  called,  resembles  the 
pia  mater  in  structure,  being  composed  of 
vessels  ramifying  minutely  in  fine  cellular 
tissue.  Its  tenuity  te  such  that  some  anato- 
mists have  doubted  its  existence,  but  we  have 
only  to  look  into  any  well-boiled  marrowbone, 
and  we  shall  no  longer  doubt.  It  may  be 
shown  too  by  roasting  a  bone,  or  macerating 
it  for  some  time  in  a  diluted  mineral  acid. 
This  membrane  sends  numberless  prolonga- 
tions from  its  inner  surface  into  the  medulla 
which  it  contains.  It  is  to  these  processes 
that  the  marrow  is  indebted  for  its  consistence ; 
they  form  cells  and  areolae  which  support  and 
maintain  the  vesicles  in  which  the  medullary 
fat  is  lodged.  They  are  exquisitely  fine,  and 
almost  invisible;  we  lacerate  them  with  a 
touch.  The  oily  substance  of  the  marrow  is 
not  in  immediate  contact  with  these  cells.  It 
is  contained  in  distinct  vesicles,which  are  beau- 
tifully figured  by  Havers.  The  vesicles  are 
little  bags  which  do  not  communicate  with 
each  other,  but  look  like  a  cluster  of  pearls, 
as  Monro  observes.  When  bones  have  been 
long  buried  or  macerated,  the  marrow  often 
assumes  a  granular  appearance  depending  on 
this  vesicular  arrangement.  A  fine  artery  runs 
to  each,  ramifies  on  it  minutely,  and  is  the 
source  of  its  secretion.  This  vessel  may  be 
demonstrated.  Each  artery  has  its  accompa- 
nying vein,  and,  though  we  cannot  see  absor- 
bents and  nerves,  their  presence  is  inferred 
from  analogy  and  various  phenomena.  Mar- 
row is  merely  a  variety  of  adipose  substance, 
and  to  the  article  on  that  subject  we  refer  for 
the  chemical  properties  and  some  generalities 
respecting  it. 

Marrow  is  not  confined  to  the  medullary 
canal.  It  is  to  be  found  in  the  cells  of  the 
spongy  extremities  of  the  long  bones,  and  in 
the  areolae  of  the  short.  It  exists  in  the  diploe 
of  the  flat  bones,  and  even  in  the  longitudinal 
canals  and  pores  of  the  compact  tissue  every 
where.  In  all  these  situations  a  membrane 
lines  the  osseous  cell  or  pore,  and  secretes  the 
contents.  The  membrane  is  still  finer  than 
that  of  the  medullary  canal,  and  the  oil  is  less 
consistent.  The  communication  between  the 
membranous  lining  is  kept  up  by  vascular 
prolongations,  not  by  a  continuity  of  cavity. 
In  the  bones  of  the  head  we  find  certain  cells, 
called  sinuses,  which  contain  air,  not  marrow. 
They  are  distinct  from  the  cells  of  the  diploe, 
with  which  they  have  no  communication. 
There  is  a  free  anastomosis  between  the  vessels 
of  the  medullary  membrane  and  those  of  the 
bone  and  periosteum  everywhere. 

Near  the  middle  of  the  long  bones  a  fora- 
men is  observed  by  which  an  artery  of  con- 
siderable size  passes  in  to  the  medullary  cavity, 
where  it  divides  into  two  branches,  one  for 
either  end.  These  extend  to  the  extremities 
of  the  canal  in  a  beautiful  network  on  its  lining 


BONE,  NORMAL  ANATOMY. 


membrane.  The  artery  is  erroneously  called 
the  nutritious  vessel  of  the  bone.  It  is  ob- 
viously intended  for  the  marrow,  A  vein  is 
seen  to  accompany  it ;  and  nerves  may  also  be 
demonstrated. 

The  medullary  membrane  is  possessed  of 
sensibility.  This  was  long  ago  shown  by  Du- 
verney.*  According  to  Bichat  it  enjoys  a  very 
high  degree  of  sensibility  in  the  centre,  but 
much  less  towards  the  £hds.  Anatomists  do 
not  agree  with  him  in  this  observation,  nor  is 
it  found  very  sensible  in  any  part.  Patients 
seldom  complain  of  pain  when,  in  amputations, 
it  is  rudely  lacerated  by  the  teeth  of  the  saw  ; 
but  sometimes  they  do  complain  loudly,  and 
in  those  cases  especially  where  the  operation 
is  performed  below  the  entrance  of  the  nerve ; 
in  the  opposite  case  the  nerve  is  probably  di- 
vided with  the  soft  parts,  and  the  sensibility, 
of  course,  destroyed. 

The  marrow  and  the  medullary  canal  vary 
much  in  different  periods  of  life,  and  under 
different  circumstances.  No  medullary  cavity 
exists  in  the  cartilage  which  precedes  bone; 
but  Bichat  asserts  that  the  membrane  is  pre- 
sent, filled  with  gelatine  of  the  same  ap- 
pearance as  the  rest  of  the  cartilage.  An 
assertion  so  improbable  a  priori,  and  so  con- 
trary to  all  observation,  seemed  to  require  some 
proof  to  support  it,  yet  he  offers  none.  When 
a  cavity  is  formed  at  a  later  period,  it  is  at  first 
occupied  entirely  by  the  artery ;  a  membrane 
soon  shows  itself  which  contains  a  reddish 
watery  substance,  of  a  gelatinous  appearance, 
not  fatty  :  it  may  be  dried  away  before  the 
fire  and  will  not  stain  paper.  To  this  the  true 
marrow  succeeds,  more  unctuous  and  more 
abundant  as  the  individual  advances  in  years. 
In  subjects,  however,  which  have  been  wasted 
by  slow  disease,  and  in  the  very  aged,  the 
marrow  again  becomes  watery,  though  not  so 
red  as  in  the  foetus.  In  the  cells  of  the  verte- 
brae there  never  is  well-formed  marrow.  It 
there  remains  through  life  sanguineous  and 
almost  destitute  of  oil. 

The  use  of  the  medullary  membrane  seems 
to  be  to  act  as  an  internal  periosteum,  or  a  bed 
in  which  the  vessels  may  ramify  before  they 
enter  the  osseous  substance.  Its  destruction 
to  any  extent  is  followed  by  the  death  of  the 
bone.  But  is  the  adeps  contained  in  it  of  any 
use  ?  Doubtless  it  is  to  the  general  system  a 
store  of  nutriment,  which  is  absorbed,  in  cases 
of  wasting  or  marasmus,  for  the  general  good  ; 
but  to  the  bone  itself  perhaps  it  is  of  no  more 
use  than  so  much  of  any  other  soft  animal 
substance  would  be — it  fills  a  space  which  in  the 
mechanism  of  the  bone  was  not  to  be  occupied 
with  calcareous  matter.  Marrow  was  lighter 
than  the  heavy  earth  of  bone,  and  could  at 
any  time  be  used  for  the  necessities  of  the 
animal.  We  see  young  bones  filled  with  a 
gelatinous  fluid,  and  in  birds  air  takes  its 
place — a  proof  that  marrow  is  no  wise  essen- 
tial to  the  existence  of  the  osseous  system. 
Various  other  uses  have  been  assigned  to  the 
marrow,  which  will  not  bear  examination. 


435 

Blumenbach,  Haller,  and  their  predecessors 
conceived  that  it  rendered  bones  more  flexible ; 
but  the  bones  of  children,  which  have  little  or 
no  marrow,  are  much  more  flexible  than  those 
of  adults.  Burning  a  bone  renders  it  brittle, 
and  this  was  said  to  be  owing  to  the  destruc- 
tion of  its  oily  part;  but  it  is  occasioned, 
clearly,  by  the  destruction  of  all  its  animal 
ingredients.  Some  were  of  opinion  that  it 
contributed  essentially  to  the  growth  and  nu- 
trition of  bone  and  to  its  union  when  fractured, 
but  bones  are  far  advanced  in  growth  before 
it  appears  at  all,  and  they  unite  faster  in 
the  young  than  in  the  old.  They  unite  also 
readily  in  birds.  Others  looked  on  it  as  the 
source  of  synovia ;  but  the  very  same  objec- 
tions hold  to  that  supposition,  and  indeed  the 
two  fluids  are  quite  dissimilar. 

According  to  the  law  of  development,  so 
generally  observed,  we  find*  fishes  and  amphi- 
bia, like  the  human  foetus,  for  the  most  part 
destitute  of  a  medullary  canal.  The  crocodile 
and  other  lizards  are,  however,  exceptions. 
Some  of  these  have  considerable  cavities. 
Birds,  when  young,  have  an  imperfect  medulla 
in  all  their  bones,  but  at  a  later  period  the 
canal  in  many  of  them  becomes  remarkably 
developed,  and  then  no  longer  contains  mar- 
row ;  air  takes  its  place,  and  fulfils  important 
offices  in  the  economy  of  the  class.  In  mam- 
malia the  internal  structure  coincides  with  that 
of  the  human  bones,  except  in  those  species 
which  have  fins.  These  approximate  to  fishes, 
and  either  contain  no  cavity  or  a  very  small 
one  filled  with  fluid  oil.  The  medulla  of  car- 
nivorous animals  generally  is  softer  than  that 
of  herbivorous. 

Organization  of  bone  as  a  part  of  the  living 
system. — The  physical  properties  of  bone  are 
so  very  peculiar  that  we  cannot  much  wonder 
at  the  mistakes  of  the  ancient  anatomists  re- 
specting its  organization.  Some  classed  it 
it  amongst  the  bloodless  organs ;  others  even 
supposed  it  to  be  destitute  of  vitality;  and 
superficial  observation  might  countenance  the 
supposition,  for  no  pain  is  excited  by  sawing, 
scraping,  or  cauterizing  a  bone ;  but  experi- 
ment and  observation,  analogy  and  disease, 
all  convince  us  that  it  possesses  well-developed 
systems  of  arteries,  veins,  nerves,  and  most 
probably  lymphatics,  not  differing  essentially 
from  those  of  the  soft  parts.  These  are  ob- 
scured by  the  presence  of  calcareous  matter, 
not  obliterated.  "  Scrape  a  bone,  and  its  ves- 
sels bleed  ;  cut  or  bore  a  bone,  and  its  granu- 
lations sprout  up ;  break  a  bone,  and  it  will 
heal ;  or  cut  a  piece  away,  and  more  bone  will 
readily  be  produced  ;  hurt  it  in  any  way,  and  it 
inflames  ;  burn  it,  and  it  dies ;  take  any  proof 
of  sensibility  but  the  mere  feeling  of  pain, 
and  it  will  answer  to  the  proof."*  Animal sen- 
sibility was  unnecessary,  it  would  even  be  incon- 
venient ;  it  is,  therefore,  not  to  be  found,  ex- 
cept in  diseased  bone,  where  it  sometimes 
exhibits  itself  too  acutely. 

The  presence  of  bloodvessels  may  be  shown 
in  various  ways.  1st.  The  colour  of  healthy 


MemoUes  de  1'Acad.  des  Sc.  1700. 


Bell's  Anatomy. 


436 


BONE,  NORMAL  ANATOMY. 


bone  in  the  living  animal  is  a  pale  pink,  which 
becomes  much  deeper  in  case  of  inflammation, 
whilst  a  deadened  portion  puts  on  a  yellowish 
white  appearance.  When  animals  are  drowned 
or  strangled,  their  bones  assume  a  darker  hue  ; 
and  in  cholera  the  colour  is  so  deep,  and  so 
thoroughly  pervades  the  osseous  tissue,  that 
no  length  of  maceration  will  remove  it.  In  all 
these  cases  the  colour  obviously  depends  on 
the  blood  contained  in  the  osseous  vessels. 
2d.  Jt  was  discovered  accidentally  by  Belchier, 
in  1736,  that  the  bones  of  animals  fed  on  food  I 
tinged  with  madder  very  quickly  become  red  ; 
(a  sensible  change  is  produced  in  young  ani- 
mals in  twenty-four  hours ;)  now,  whether  we 
explain  this,  with  most  physiologists,  by  saying 
that  the  earthy  matter  is  coloured  in  the  blood 
before  it  is  deposited,  or,  with  Gibson,  that  it 
receives  its  dye  in  the  bone,  the  presence  of 
bloodvessels  is  equally  necessary  to  account 
for  the  phenomenon.  (See  OSTEOGENY.) 
3d.  The  most  satisfactory  proof  of  vascularity 
in  bone  is  afforded  by  injection.  A  young 
bone  may  be  completely  coloured  in  this  way : 
the  vessels  are  seen  to  enter  it,  and  if  the 
earthy  part  be  removed  by  an  acid,  they  may 
be  followed  in  their  fine  ramifications  through 
its  tissue. 

Arteries  are  found  to  enter  bone  under  three 
modifications.  1st.  Numerous  small  vessels 
fill  the  minute  foramina,  which  may  be  seen 
in  the  compact  substance  every  where :  2d,  a 
larger  set  enter  the  holes  which  we  see  on  the 
short  bones,  and  near  the  extremities  of  the 
long  ones:  and  3d,  about  the  centre  of  the 
long  bones  considerable  branches  pass  into  the 
medullary  canal,  and  ramify  on  the  medullary 
membrane.  These  last  have  been  called  the 
nutritious  arteries,  a  name  to  which  they  have 
no  claim  :  they  are  destined  for  the  marrow. 
The  two  first  sets  are  the  true  nutritious  ves- 
sels. All,  however,  freely  anastomose  with 
each  other. 

The    veins  merit  particular  notice.     They 

Fig.  187. 


have  been  investigated  by  Dupuytren,*  and 
their  course  in  some  of  the  bones,  espe- 
cially the  flat  bones,  splendidly  figured  by 
Brescbet.f  In  Jigs.  187,  and  188,  copied  from 
one  of  Breschet's  plates,  a  indicates  these  veins 
in  the  diploe  of  the  cranium :  they  may  be 
very  easily  exposed  in  the  cranium  by  filing 
away  the  external  table  with  a  coarse  file. 
The  first  two  sets  of  arteries  have  no  accom- 
panying veins,  but  with  the  last  there  always 
are  veins  of  a  corresponding  size.  These  do 
not  appear  large  enough  to  return  all  the  blood ; 
we  therefore  have  others  leaving  the  bone  by 
foramina,  which  are  proper  to  them,  and 
through  which  no  artery  passes.  They  arise  in 
the  spongy  tissue  by  numberless  radicles,  re- 
ceive branches  like  other  veins  in  their  course, 
and,  after  issuing  from  the  compact  tissue  by 
a  constricted  opening,  empty  themselves  into 
the  vessels  of  the  neighbouring  soft  parts. 
The  canals  through  which  they  pass  have  a 
lining  of  compact  substance  continuous  with 
the  external  surface.  The  veins,  while  in  the 
bone,  have  only  one  coat,  the  internal,  which 
adheres  closely  to  the  osseous  canal,  and  can 
enjoy  no  change  of  size  or  form.  They  are, 
notwithstanding,  furnished  with  valves. 

Nerves,  doubtless,  exist  in  bone,  although 
we  cannot  demonstrate  them  in  the  osseous 
substance.  But  it  is  not  to  be  supposed  that 
a  part  so  highly  vascular  would  be  destitute 
of  nerves.  Nerves  are  seen  to  enter  with  the 
nutritious  vessels,  and  minute  filaments  pass 
into  some  bones,  as  the  frontal.  These  nerves, 
we  may  be  sure,  ramify  through  every  part. 
The  sensibility  of  an  inflamed  bone  indeed 
settles  the  question. 

Lymphatics  have  not  been  found  in  the  inte- 
rior of  the  osseous  substance;  but  they  may 
be  seen  on  the  surface.^  In  a  tissue  such  as 
that  of  bone  it  would  be  no  easy  matter  to 

*  Propositions  sur  quelques  points  d'Anatomie, 
de  Physiologic,  et  d'Anatomie  Pathologique.  Par. 

t  Recherches   Anal,   sur    le    systeme    veiueux. 
Par.  1829. 
|  Beclard.  Grainger. 


BONE,  NORMAL  ANATOMY. 


407 


exhibit  them,  even  if  they  existed  in  great 
numbers.  That  they  do  so  exist  we  have  reason 
to  think  from  the  phenomena  of  mollities, 
exfoliation,  and  various  other  morbid  actions, 
as  well  as  the  changes  which  daily  occur  in 
the  growth  of  bone. 

3.  C/ieniicul  composition. — V\  hen  bone  is 
heated  to  redness  in  an  open  fire,  some  of  its 
ingredients  are  consumed,  and  a  white  friable 
earth  is  left  behind.  Again,  if  bone  be  ex- 
posed for  some  time  to  the  action  of  an  acid,  it 
becomes  soft  and  flexible.  In  both  cases  the 
form  and  size  of  the  original  are  retained,  but 
there  is  considerable  loss  of  weight.  These 
facts  were  well  known  in  the  infancy  of  science; 
they  were  too  obvious  to  escape  notice ;  but  it 
does  not  appear  that  they  were  explained  before 
the  time  of  Nesbit  in  1736,*  nor  very  satis- 
factorily then.  The  existence  of  an  earthy  and 
an  animal  matter  was  afterwards  proved  by 
Herissant,  who  showed,  by  experiment,  that 
acids  did  not  soften  the  osseous  substance  as  a 
whole,  but  removed  from  it  the  earthy  portion; 
and  that  the  soft  animal  matter  was  always 
present,  but  concealed  by  an  earthy  "  incrus- 
tation" of  its  fibres.f  The  action  of  fire  on 
the  animal  portion  was  easily  explained.  Some 
time  after  this  Gahn  discovered  that  the  earth 
was  principally  a  phosphate  of  lime  ;  and  later 
chemists,  especially  Berzelius,  have  minutely 
investigated  the  nature  and  proportions  of  these 
different  ingredients.  It  is  now  ascertained 
that  bones  contain  several  earthy  salts,  varying 
a  little  in  different  animals;  that  the  earthy 
and  the  animal  parts  do  not  always  bear  the 
same  proportion  to  each  other  in  the  different 
classes ;  and  that  even  in  the  same  individual 
age  and  situation  give  rise  to  varieties. 

It  was  long  believed  that  fat  formed  an 
essential  part  of  bone,  and  that  very  important 
properties  depended  on  its  mixture  with  the 
osseous  tissue;  but  this  opinion  was  quite 
erroneous.  Fat  is  not  always  present,  and 
when  it  is,  it  invariably  belongs  to  the  medulla, 
which  may  be  looked  upon  as  a  distinct  struc- 
ture superadded  to  bone.  It  is,  as  it  were, 
an  accidental  deposit,  and  is  not  to  be  con- 
sidered in  the  analysis. 

On  removing  the  fat  and  periosteum,  if  we 
suspend  a  bone  for  some  days  in  diluted  mu- 
riatic acid,  the  earthy  part  is  dissolved,  whilst 
nearly  all  the  animal  portion  remains  untouched. 
This  last  is  soft,  translucent,  and  of  a  yellowish 
white  colour.  It  is  called  the  cartilage  of  bone. 
When  washed  and  dried  it  contracts  a  little, 
assumes  a  deeper  colour,  though  still  retaining 
some  translucency,  becomes  hard  and  tough, 
and  weighs  about  one-third  of  the  original 
bone.  This  substance  yields,  on  being  boiled, 
a  quantity  of  gelatine,  which  in  young  subjects 
is  very  considerable,  forming  nearly  all  the 
cartilage,  but  in  the  old  a  soft,  white,  elastic 
substance  still  remains,  possessing  the  figure  of 
the  bone.  According  to  Hatchet's  experiments 


this  last  has  the  properties  of  coagulated  albu- 
men.* Berzelius,f  however,  shows  that  all 
the  cartilage  may  be  resolved  by  boiling  into  a 
clear  colourless  gelatine,  which  leaves  on  the 
filter  only  a  very  small  quantity  of  fibrous  sub- 
stance, the  debris  of  vessels.  He  does  not 
admit  the  existence  of  any  albuminous  nidus, 
and  even  looks  upon  the  gelatine  as  the  pro- 
duct of  a  decomposition  effected  by  coction  on 
the  peculiar  cellular  basis  of  bone. 

The  earth  of  bone  is  principally  subphos- 
phate  of  lime;  it  also  contains  carbonate  of 
lime  and  minute  quantities  of  other  salts.  The 
following  is  the  analysis,  as  given  by  Berzelius, 
of  bone  deprived  of  its  oil,  blood,  and  perios- 
teum : — 

Bones  of  man. 

Cartilage  completely  solu- 
ble in  water 32' 

Vessels 

Subphosphate  of  lime  with 

a  little  fluate  of  lime. ...  53-04 

Carbonate  of  lime 11-30 

Phosphate  of  magnesia    ..      rl6 
Soda,  and  a  very  little  mu- 
riate of  soda 1-20 


ui    man* 

12-17  S 
1-133 


Of  the  ox. 


33-30 


100-00 


57-35 
3-85 
2-05 

3-45 
100-00 


The  proportion  of  earthy  and  animal  matter 
is  the  same  generally  in  man  and  the  other 
mammalia.  In  birds  there  is  more  of  the 
animal  part  which  does  not  perfectly  dissolve 
than  in  mammalia.  In  reptiles  and  osseous  fishes 
the  cartilage  of  bones  approaches  in  its  nature 
to  the  substance  which,  in  cartilaginous  fishes, 
is  the  substitute  for  bone.  This  substance  is 
of  a  peculiar  nature ;  it  yields  neither  gelatine 
nor  albumen,  but  is  more  analogous  to  inspis- 
sated mucus  than  to  any  thing  else. 

The  earthy  salts  are  not  always  in  the  same 
proportion  to  each  other  in  different  animals. 
We  have  seen  that  they  are  not  the  same  in 
man  and  the  ox.  Barros  gives  the  following 
table : — 

Phosphate  of  lime.  Carbonate  of  lime. 

Lion 95-0   2*5 

Sheep 83-0   19-3 

Fowl 88-9 10-4 

Frog 95'2 2*4 

Fish    91-9 5-3 

With  respect  to  varieties  depending  on  age 
and  situation,  we  have  a  table  of  the  proportions 
of  animal  matter  and  earth  as  found  by  Dr. 
John  Davy  in  several  experiments,  from  which 
it  appears  that  old  bones  contain  more  earth 
than  young  ones,  and  that  the  bones  of  the 
head  have  a  greater  proportion  than  those  of 
the  extremities.]; 

As  to  the  exact  nature  of  the  earthy  salts, 
we  have  given  the  results  obtained  by  Ber- 
zelius as  the  latest  and  most  accurate.  But 
it  may  be  right  to  state  that  differences  of 


*  Human  Osteogeny,  by  R.  Nesbit,  M.D.  p. 
31.  Loud.  1736. 

t  Meraoires  dc  1'Acadcmie  Royalc  des  Sciences, 
1758. 


*  Philosophical  Transactions,  1800. 
f  Traite  de  Chimie,    Par.  1833. 
|   See    Monro's    Elements   of  Anatomy. 
Edinb.  1825. 


/ol. 


438 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


opinion  exist  on  this  point.  Even  Berzelius 
expresses  a  doubt  whether  magnesia  is  met 
with  as  a  phosphate  or  a  carbonate.  We  find 
iron  mentioned  by  Fourcroy  and  Vauquelin  as 
present  in  bone.  This,  according  to  Berzelius, 
depends  on  the  red  blood  which  its  vessels 
happen  to  contain.  They  also  mention  silica, 
alumina,  and  phosphate  but  no  fluate  of  am- 
monia. 

4.  Its  peculiarities  in  other  animals. —  In 
the  course  of  this  article  we  have  noted  the 
most  striking  of  those  peculiarities,  so  that 
little  need  be  said  under  the  present  head. 

The  Radiata,  Articulata,  and  Mollmca 
have  coverings  which  somewhat  resemble  bone, 
and  are  considered  by  some  physiologists  as  the 
osseous  system  of  these  classes.  This  opinion 
will  be  examined  in  another  place. 

Fishes. —  Cartilaginous  fishes  have  very  little 
earthy  matter  in  their  skeleton,  so  that  their 
bones  scarcely  deserve  the  name.  They  are  very 
flexible,  elastic,  homogeneous,  and  semi-trans- 
parent, and  in  chemical  composition  resemble 
inspissated  mucus.  Osseous  fishes  have  bones 
properly  so  called.  They  are  more  flexible 
than  in  the  higher  classes,  have  no  medullary 
cavity,  little  of  the  spongy  tissue,  and  make 
no  approach  to  the  laminated  arrangement. 

Amphibia  have  no  appearance  of  lamina  in 
their  bones,  nor,  with  the  exception  of  the 
crocodile,  a  medullary  cavity.  In  chemical 
composition  they  resemble  those  of  fishes. 

Birds  have  firm,  elastic,  and  thin  bones, 
shewing  less  of  the  cellular  and  more  of  the 
laminated  disposition  than  we  meet  with  in  the 
other  classes.  They  have  large  and  well  deve- 
loped cavities,  which  contain  air  instead  of 
medulla. 

Mammalia. — The  bones  of  the  cetacea  are 
coarse  and  fibrous  externally.  Within  they  are 
spongy  or  cellular,  but  the  cells  assume  a  re- 
markable tubular  disposition.  There  is  no 
medullary  canal.  The  bones  of  quadrupeds 
do  not  differ  much  from  those  of  man.  In 
general  they  are  of  a  coarser  texture,  and  in 
some,  as  in  those  of  the  head  of  the  elephant, 
we  find  very  extensive  air-cells. 

BIBLIOGRAPHY. — Leuwenhoeck,  Microscop.  Obs. 
in  Phil.  Trans.  1674  and  1678.  Malpighi,  De 
ossium  structura,  in  Ej.  Anat.  Plantar,  i'ol.  Lond. 
1675,  et  in  Ej.  Op.  Pokth.  Venet.  1743,  Lond.  1697. 
Havers,  Osteologia  nova,  8vo.  Lond.  1681.  Gagli- 
ardi,  Anatome  ossium,  8vo.  Lugd.  Bat.  1723. 
De  La  Sone,  Mem.  i.  et  ii.  sur  1'organization  des 
Os.  Mem.  de  Paris,  1751.  Albinus,  De  construc- 
tione  ossium,  in  Annot.  Acad.  lib.  vii.  Scarpa, 
De  penitiori  ossium  structura  Com.  4to.  Lips.  1799 : 
4to.  Paris,  1804  j  Ticin.  1827,  s.  t.  :  De  anat.  et 
pathol.  oss.  Malacarne,  Auct.  ad  osteologiam,  &c. 
Ludwigii  et  Scarps,  Padov.  1801.  Caldani,  Mem. 
sulla  struttura  della  ossa  umana  e  bovina,  4to. 
Padov.  1804.  Howship,  Microscopic  observations 
on  the  structure  of  bone,  in  Med.  Chir.  Trans. 
vol.  vii.  Medici,  Esperienze  intorno  alia  tessitura 
organ,  delle  ossa,  in  Opusc.  Scientif.  t.  ii.  Bologna, 
1818.  Speranxa,  Consid.  sul.  tessitura  organ,  delle 
ossa,  Bolog.  1819.  Ilmoni,  Physiol.  syst.  oss. 
spec.  i.  et  ii.  4to.  Aboae,  1825,-6.  See  also  the 
various  systems  of  general  and  descriptive  anatomy 
and  of  physiology,  and  further  in  the  Bibliography 
of  OSSEOUS  SYSTEM  and  OSTEOGENY. 

(Charles  Benson.) 


BONE,  PATHOLOGICAL  CONDI- 
TIONS OF.— The  bones,  as  the  foundations  of 
the  animal  system,  as  the  passive  organs  of  loco- 
motion, required  necessarily  to  be  firm  and  com- 
paratively inelastic  and  unyielding,  qualities 
which  we  have  seen  in  the  preceding  article  are 
imparted  to  them  by  the  addition  to  their  original 
animal  elements  of  a  saline  or  earthy  substance, 
consisting  principally  of  phosphate  of  lime. 
It  is  obvious  that  this  difference  of  structure 
and  constitution  must  have  considerable  in- 
fluence in  modifying  the  diseases  to  which 
they  are  liable,  and  in  giving  to  the  affections 
of  these  organs  many  of  their  distinguishing 
peculiarities.  In  considering,  therefore,  the 
phenomena  exhibited  in  the  various  patholo- 
gical conditions  of  the  osseous  system,  not 
only  must  the  presence  of  this  unorganized 
earthy  substance  be  constantly  borne  in  mind, 
but  even  its  relative  amount,  its  abundance  or 
deficiency  must  command  attention.  In  early 
life,  when  the  animal  material  preponderates 
in  quantity,  the  bones  are  highly  vascular,  and 
comparatively  soft,  flexible,  and  springy,  and 
though  liable  to  many  serious  diseases,  they 
are  very  apt  to  escape  the  effects  of  injury  : 
fracture  is  uncommon  in  infancy;  and  in  child- 
hood the  bones,  bending  rather  than  breaking, 
often  exhibit  that  partial  fracture  which  has 
been  likened  to  a  "  branch  of  a  tree  that 
yields  to  an  attempt  to  break  it  while  it  still 
retains  its  sap."*  The  powers  of  repair  are 
commensurate  with  the  extent  of  vascular  or- 
ganization at  this  period ;  fracture  is  quickly 
re-united,  and  its  effects  so  regulated  by  the 
subsequent  growth  of  the  bone  that  permanent 
deformity  is  a  very  infrequent  occurrence. 

But  this  activity  in  the  osseous  system  in 
early  life  has  its  evils.  The  period  of  youth, 
between  absolute  childhood  and  puberty,  is 
that  in  which  disease  is  most  easily  and,  there- 
fore, most  frequently  developed,  and  although 
extensive  powers  of  reparation  are  constantly 
exhibited  in  recovery  after  caries,  in  re- 
production after  necrosis  &c.,  still  are  the 
operations  that  lead  to  these  results  languid 
and  too  often  inefficient, — circumstances  that 
may  be  attributed  partly  to  peculiarity  of  or- 
ganization in  the  structure  affected,  but  per- 
haps with  more  propriety  to  the  influence  of 
some  general  constitutional  taint  over  which 
medicine  exerts  but  slender  control. 

The  osseous  system  cannot  be  considered  as 
having  attained  maturity  until  a  period  sub- 
sequent to  the  age  of  puberty,  most  commonly 
somewhere  between  the  twenty-seventh  and 
thirtieth  years.  At  this  lime  bone  is  calculated 
most  perfectly  to  answer  its  purposes  in  the 
animal  economy :  it  is  then  least  liable  to 
disease ;  and  if  fractures  and  other  injuries 
are  more  frequent,  it  is  only  because  indivi- 
duals are  now  more  exposed  to  them.  The 
effects  of  these  injuries  are  in  general  repaired 
sufficiently  well,  but  if  deformity  has  been 
produced  it  will  be  permanent,  because  the 
bone  has  ceased  to  grow. 

*  See  a  paper  on  this  subject  by  Dr.  Hart,  vol.  i. 
Dublin  Journal  of  Medical  Science. 


BONE,  PATHOLOGICAL  CONDITIONS  OF.  439 

As  life  advances,  the  osseous  system  un-  we  cordially  agree  in  the  opinion ;  being 
dergoes  many  obvious  alterations.  The  satisfied  that  the  results  of  chemical  or  me- 
shape  of  some  bones  is  altered  :  the  natural  chanical  enquiries,  however  true  in  themselves, 
curvatures  of  the  long  bones,  for  example,  are  will  always  be  insufficient  to  explain  the  ope- 
increased  ;  the  direction  of  the  processes  and  rations  carried  on  within  a  living  body, 
parts  of  others  is  changed,  the  most  remarkable  Having  offered  these  preliminary  remarks, 
example  of  which  occurs  in  the  neck  of  the  we  proceed  with  an  attempt  at  an  arrangement 
thigh-bone ;  and  their  powers  of  affording  sup-  of  the  pathology  of  the  osseous  system,  fully 
port  and  resisting  violence  are  obviously  en-  aware,  indeed,  that  every  classification  of  dis- 
feebled.  This  senile  fragility  has  been  gene-  ease  must  be  more  or  less  artificial,  and,  there- 
rally  supposed  to  arise  from  an  increase  in  the  fore,  open  to  objection.  Perhaps  it  may  be 
earthy  material  of  the  bones.  The  opinion,  advantageously  considered  under  the  three  fol- 
however,  has  not  been  invariably  borne  out  by  lowing  heads.  1.  Cases  in  which  there  is  a 
the  results  of  chemical  analysis  of  bones  at  real  or  supposed  derangement  or  imperfection 
different  periods  of  life,  and  has  been  objected  in  the  processes  carried  on  within  the  bone 
to  by  M.  Ribes,*  who,  after  extensive  obser-  itself  in  order  to  its  maintenance  in  the 
ration  and  enquiry,  was  led  to  believe  "  that  normal  or  healthy  condition.  2.  Cases  in 
the  fragility  of  bones  depended  essentially  on  which  there  is  inflammation  of  the  bone, 
a  change  of  action  being  established  within  whether  produced  by  injury,  appearing  idio- 
them,  and  that  all  the  parts  entering  into  the  pathically,  or  connected  with  some  specific 
texture  of  bones  are  really  in  less  quantity  in  taint.  The  pathological  conditions  of  the  pe- 
the  aged  than  in  younger  individuals."  If  riosteum  are  so  intimately  connected  with  tins 
by  "  a  change  of  action"  in  the  above  passage  part  of  the  subject,  that  some  reference  to  its 
is  meant  that  gradual  decrease  of  the  vital  diseases  must  of  necessity  be  made.  3.  Cases 
properties  observed  in  every  organ  and  in  every  in  which  there  is  alteration  of  the  original  struc- 
tissue  as  man  declines  into  the  vale  of  years,  ture  or  development  of  a  new  one  ;  as  thus : — 

DISEASES    OF   THE    OSSEOUS    SYSTEM. 

CLASS  i.     Derangements  of  internal  functions. 

a.  Deficiency  of  the  calca- 

reous deposit Rachitis. 

b.  Superabundance   of  the 

calcareous  deposit  ..Fragility. 

c.  Absorption  of  the  calca- 

reous deposit Mollities. 

d.  Absorption  of  both  con- 

stituents   Atrophy. 

CLASS  ir.     Inflammation. 

a.  Simple  inflammation   .  .Adhesion    Union  of  fracture. 

Suppuration    Abscess  in  bone. 

Ulceration Caries. 

Mortification Exfoliation. 

Death  with  regeneration    Necrosis. 

b.  Specific  inflammation  . .  Scrofula Absorption  of  cancelli. 

Deposit    of    a    cheesy 
substance. 

Softening  of  the  bone. 

Abscess. 

Caries. 

Syphilis Deposit  of  fluid  between 

the    periosteum    and 
bone.     Node. 

Caries. 
CLASS  in.     Structural  diseases. 

a.  Spina  ventosa Development  of  a  new  cavity  within  a 

bone,  with  unnatural  contents. 

b.  Exostosis Growth  of  a  tumour  in  or  from  a  bone, 

which  may  consist  of Bone. 

Cartilage. 

Both  structures  mixed. 

c.  Osteo-sarcoma Alteration  of  structure  with  deposit  of 

a  new  material. 

d.  Cancer.f 

e.  Fungus  hsematodes.f 

f.     Bloody     cellulated     tu- 
mour within  bone. 

*  We  refer  our  readers  for  a  summary  of  M.  Ribes'  opinions,  &c.   to  the  Dictionnaire  dcs  Sciences 
Medicales,  rol.  xxxviii.  p.  456  ct  scq. 

t  These  diseases  are  generally,  if  not  always,  propagated  from  a  jacent  parts  or  structures. 


410 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


Rickets. — The  consideration  of  this  subject 
has  been  too  frequently  mixed  up  with  that  of 
the  disease  entitled  mollities  ossium  (osteo- 
malaxie),  or  with  that  of  the  interstitial  absorp- 
tion of  bone  which  occurs  in  aged  persons. 
Kachitis  seems  not  to  be  so  much  a  softening 
of  bone  that  had  previously  been  solid  and 
perfect,  as  an  interruption  in  the  first  instance 
of  the  process  of  ossification.  It  is  a  disease 
of  early  life,  generally  commencing,  or  at 
least  first  observed  about  the  period  when  the 
infant  should  make  its  earliest  attempts  to  walk, 
and  rarely  appearing  after  the  age  of  two  years. 
It  would  appear  that  the  disease  should  be 
considered  as  connected  with  inadequate  nu- 
trition throughout  the  body  generally,  rather 
than  as  being  confined  to  the  osseous  system  ; 
its  effects  are  only  most  obviously  marked  on 
that  system  ;  and  it  is  quite  certain  that  all 
the  bones  of  the  skeleton  are  more  or  less  af- 
fected, although  particular  local  causes  com- 
monly produce  much  greater  deformity  in  one 
than  in  another. 

The  early  symptoms  of  rickets  are  invariably 
those  of  imperfect  or  deranged  nutrition,  pale- 
ness of  skin,  flaccidity  of  fibre,  &c.  Along 
with  these  symptoms  or  shortly  succeeding  to 
them  the  deformities  appear  which  cause  the 
disease  to  be  ranked  amongst  the  affections  of 
the  osseous  system.  In  mild  cases  these  ex- 
tend no  farther  than  to  an  increase  in  the  cur- 
vature of  some  of  the  long  bones  and  an  aug- 
mented expansion  of  their  extremities.  Whether 
from  its  supporting  the  whole  weight  of  the  body 
or  from  the  action  of  the  strong  muscles  behind 
it,  the  tibia  generally  suffers  in  a  remarkable 
degree:  the  legs  are  not  only  bent  forwards, 
the  curve  being  sharp  and  sudden  about  the 
lower  third  of  the  bone,  but  they  are  twisted  in 
such  a  manner  as  to  bring  the  internal  ankle 
below  its  proper  level,  deformities  which,  not- 
withstanding a  perfect  recovery,  are  never  com- 
pletely removed  afterwards.  Rickets,  consi- 
dered alone,  is  not  very  dangerous  to  life :  in 
most  instances  it  proceeds  no  farther  than  has 
been  already  described — the  visceral  derange- 
ments are  either  subdued  or  subside  sponta- 
neously, the  healthy  functions  are  re-estab- 
lished, and  amongst  them  that  of  ossification, 
and  the  patient  soon  becomes  enabled  to  per- 
form the  ordinary  motions,  while  the  deformity 
in  some  slight  degree  disappears.  But  if  the 
disease  is  severe  or  protracted,  or  complicated 
with  a  scrofulous  taint,  it  generally  leaves 
tokens  behind  it  which  embitter  the  patient's 
future  existence,  or  hurry  him  to  a  premature 
grave.  Sometimes  the  head  becomes  flattened, 
or  pushed  so  as  to  project  backwards,  or  is 
otherwise  strangely  deformed.  More  frequently 
still  the  chest  suffers  in  shape,  either  in  the 
ribs,  the  spine,  or  in  both,  and  the  compressed 
and  contracted  thorax,  or  laterally  curved  spine, 
with  all  their  accompaniments  and  consequences 
of  deranged  respiration,  will  be  the  result.  But 
of  all  the  parts  which  suffer  from  this  disease, 
perhaps  the  pelvis  is  that  which  is  most  fre- 
quently engaged.  Placed  between  the  spine 
and  the  thighs,  it  is  the  fulcrum  and  centre  on 
which  numerous  motions  are  performed  ;  it  is 


surrounded  by  powerful  muscles  and  subjected 
to  irregular  and  unequal  pressure  ;  and  it  also 
sustains  the  weight  of  the  principal  part  of  the 
body.  Hence  arise  the  strangest  and  some- 
times the  most  complicated  distortions,  and 
woe  to  the  female  who  at  the  age  of  woman- 
hood becomes  pregnant  under  such  circum- 
stances. The  remote  consequences  of  rickets 
may,  therefore,  be  far  more  formidable  than 
the  immediate. 

The  actual  condition  of  a  bone  with  reference 
to  its  structure  is  the  next  point  to  which  we 
must  direct  our  attention.  Is  there  an  absolute 
deficiency  in  the  quantity  of  ossific  matter 
secreted,  the  place  of  which  is  supplied  (espe- 
cially about  the  epiphyses  of  the  bones)  by  a 
soft  substance  which  increases  their  bulk  ?  or  is 
the  earthy  material  removed  by  absorption 
previous  to  the  deposition  of  this  softer  sub- 
stance ?  The  question  is  not  easily  answered, 
for  patients  seldom  die  of  rickets  alone ;  and 
when  they  perish,  it  is  generally  in  consequence 
of  some  complication  of  scrofula  producing 
hydrocephalus,  tabes  mesenterica,  glandular 
abscesses,  or,  it  may  be,  caries ;  and  it  is  evi- 
dent that  the  examination  of  a  case  so  mixed 
cannot  afford  a  satisfactory  demonstration  of 
the  disease  itself.  It  cannot,  therefore,  be  a 
matter  of  surprise  if  some  difference  of  opinion 
has  existed.  The  following  is  the  description 
of  a  ricketty  bone  as  given  by  Boyer.*  It  is 
lighter,  of  a  red  or  brown  colour,  pierced  by  a 
great  number  of  dilated  bloodvessels,  porous 
and  spongy,  soft  and  compressible,  moistened 
with  a  sort  of  sanies  that  may  be  pressed  out 
as  from  a  sponge,  or  rather  from  leather  that 
has  been  soaked  to  maceration.  The  walls  of 
the  medullary  cylinder  of  the  long  bones  of 
the  extremities  are  greatly  thinned,  whilst  the 
bones  of  the  skull  are  increased  in  thickness 
and  become  spongy,  and,  as  it  were,  reticulated. 
Both  the  one  and  the  other,  but  especially  the 
long  bones,  have  acquired  a  remarkable  sup- 
pleness, but  when  bent  beyond  a  certain  point 
they  break  :  and  the  fracture  takes  place  more 
easily  if  the  inflexion  is  made  rapidly.  The 
medullary  cavity  of  the  long  bones  contains, 
instead  of  marrow,  a  reddish  serosity,  totally 
devoid  of  that  fat  and  oily  character  which 
appertains  to  marrow  in  its  natural  state.  The 
result  of  Mr.  Stanley'sf  experience  is  that  the 
consistence  of  a  ricketty  bone  is  but  slightly 
different  from  that  of  common  cartilage,  an 
opinion  more  consonant  with  our  notions  of 
the  disease  than  Boyer 's  exaggerated  descrip- 
tion is  calculated  to  convey.  We  ourselves 
have  never  met  with  that  extreme  degree  of 
softness  which  has  been  occasionally  described, 
or  which  would  permit  of  the  bone  being  di- 
vided by  a  knife.  Meckel  J  states  that  the  bones 
of  ricketty  patients  are  soft,  spongy,  flexible, 
and  curved,  both  in  situations  where  they  are 
subjected  to  muscular  actions,  and  where  they 
have  some  weight  to  support.  In  the  meantime 


*  Boyer,  Traite  des  Maladies  Chirurgicales,  torn, 
iii.  p.  625. 

t   Medico-Chirurgical  Transactions,  vol.  vii. 
$  Meckel,  Manuel  d'Anatomie,  torn.  i.  p.  344. 


BONE,   PATHOLOGICAL  CONDITIONS  OF. 


441 


they  receive  more  blood.  The  periosteum  has 
undergone  analogous  changes.  The  chemical 
composition  is  not  the  same  throughout.  Thus, 
on  the  one  hand,  there  is  not  always  the  same  rela- 
tion between  the  respective  proportions  of  phos- 
phoric acid  and  lime — sometimes  too  much, 
sometimes  too  little  of  the  acid  :  on  the  other, 
the  proportion  between  the  animal  and  earthy 
substance  varies  considerably.  Sometimes  the 
quantity  of  animal  matter  is  greatly  increased, 
so  that  the  relation  is  74 : 26,  or  even  75,8 : 24,2, 
or  so  far  as  79,54  :  20,6.  Often  it  is  the  same 
as  that  met  with  in  the  healthy  condition,  or  it  is 
even  less,  as  25,5  :  74,5,*  although  the  bones  are 
spongy.  These  differences  depend  probably 
on  the  intensity,  and,  more  particularly,  on  the 
period  of  the  disease  ;  but  they  prove,  at  least, 
that  the  essence  of  rickets  does  not  consist  in 
an  original  deficiency  of  earthy  material. 

It  is  unnecessary  to  quote  any  farther  autho- 
rities to  shew  that  no  universality  of  opinion 
prevails  as  to  the  pathology  of  this  important 
disease,  and  that  it  still  requires  careful  and 
accurate  investigation.  It  seems,  however,  to 
be  agreed  on,  that  when  the  patient  begins  to 
recover,  a  great  activity  may  be  observed  in  the 
deposition  of  the  earthy  material,  and  that  it  is 
principally  deposited  where  it  is  most  wanted, 
viz.  on  the  concave  surfaces  of  the  curves. 

Fragilitas. — We  have  classed  a  brittle  con- 
dition of  the  bones  under  the  head  of  a  dispro- 
portionate abundance  of  the  earthy  substance, 
rather  in  compliance  with  a  doctrine  that  was 
once  universally  believed,  and  perhaps  is  still 
pretty  generally  admitted,  than  as  the  statement 
of  a  fact  that  may  be  supported  by  evidence. 
It  was  supposed  that  the  presence  of  a  greater 
quantity  of  phosphate  of  lime  rendered  the 
bone  short-grained  and  dry,  and  therefore 
more  liable  to  snap  across  ;  and  this  condition 
of  bone,  as  peculiarly  appertaining  to  old  age, 
has  been  placed  by  Boyer  among  the  predis- 
posing causes  of  fracture.f  The  opinions  of 
Ribes  on  this  subject,  and  the  doubt  cast  by 
chemical  analysis  on  the  ordinary  explanations 
of  a  softened  condition  of  bone  on  the  one 
hand,  and  of  its  fragility  on  the  other,  have 
been  already  noticed,  and,  notwithstanding  some 
attention  to  the  subject,  we  are  obliged  to  leave 
it  without  even  attempting  a  solution  of  the 
difficulty ;  the  results  even  of  several  series  of 
experiments,  which  were  instituted  in  the  years 
1831  and  1832,  with  a  view  to  the  elucidation 
of  this  difficult  question,  scarcely  deserve  to  be 
stated,  as  they  were  in  every  respect  unsatis- 
factory. We  compared  the  respective  thick- 
ness of  the  thigh-bone  in  the  adult  and  the 
aged,  the  section  being  made  exactly  in  the 
middle  :  we  weighed  equal  lengths  of  similar 
bones — we  softened  equal  lengths  and  equal 
weights  by  means  of  dilute  muriatic  acid — 
and  we  burned  equal  portions  and  weights 
also,  with  a  view  of  comparing  them  under 
these  different  circumstances,  but  could  never 


*  These  chemical  results  are  quoted  by  Meckel 
from  Monro's  Outlines  of  Anatomy. 

t  Traitc  des  Maladies  Chirurgicales,  torn.  iii.  p. 
22. 


arrive  at  any  fixed  or  certain  conclusions.  In 
one  remarkable  instance  the  bone  of  a  wo- 
man, who  must  have  been  seventy  or  eighty 
years  of  age,  was  thicker,  stronger,  and  con- 
tained more  both  of  the  animal  and  earthy 
materials  than  any  adult  bone  with  which  it 
was  compared.  We  were,  therefore,  obliged 
to  adopt  M.  Kibes'  theory  of  "  a  change  of 
action,"  just  as  we  see  the  muscle  of  an  old 
man  incompetent  to  such  a  display  of  strength 
as  would  be  easy  to  that  of  a  younger  person, 
although  the  latter  may  be  smaller,  and  pos- 
sessed apparently  of  less  toughness  of  fibre. 

Fragility  seems  to  exist  under  two  different 
conditions,  one  derived  from,  or  having  rela- 
tion to,  some  defect  or  imperfection  in  the 
bone  itself;  the  other  being  rather  a  symptom 
of  some  other  disease  than  a  disease  itself,  and 
arising  from  some  vice  or  taint  in  the  constitu- 
tion. The  former  of  these  is  exhibited  in  the 
fragility  occasionally  observed  in  the  bones  of 
some  young  persons,  and  more  constantly  in 
those  of  the.  old  ;  but  it  may  be  remarked  that 
the  causes  that  produce  this  fragility  (whatever 
they  are)  do  not  interfere  with  the  restorative 
powers  of  the  part.  True,  a  fractured  bone  is 
tedious  in  uniting,  and  is  frequently  followed 
by  unpleasant  consequences  in  aged  persons, 
but  in  such  all  the  vital  powers  exhibit  evi- 
dence of  sluggishness  and  debility;  whilst  in 
youth,  so  far  from  fragility  interfering  with  the 
process  of  union,  fractured  bones  have  been 
observed  to  be  consolidated  in  even  less  than 
the  usual  period.  But  when  any  particular 
condition  of  constitution  or  any  disease  seems 
to  be  the  exciting  cause  of  fragility,  it  may 
also  be  regarded  as  a  cause  of  subsequent  non- 
union. Of  these,  cancer,  fungus  haematodes, 
and  sea-scurvy,  seem  to  furnish  the  most  nu- 
merous and  best  authenticated  instances ;  sy- 
philis has  been  added,  probably  from  the  fact 
of  some  fractures  remaining  disunited  until 
the  patients  had  been  subjected  to  a  course  of 
mercury;  its  influence,  however,  is  question- 
able, unless  where  it  had  previously  produced 
caries.  A  state  of  pregnancy  or  of  lactation 
has  been  mentioned  as  predisposing  to  fracture, 
and  impeding  or  delaying  the  process  of  re- 
union; but  however  the  observation  might 
have  been  occasioned  by  a  few  solitary  cases, 
it  is  not  borne  out  by  general  experience. 

In  the  fragility  of  early  youth,  and  where 
union  would  take  place  quickly  and  kindly,  it 
is  not  to  be  expected  that  the  bone  (if  there 
was  an  opportunity  of  examining  it)  should 
present  any  morbid  appearances  unless  the 
evidences  of  its  physical  weakness  in  the  small- 
ness  of  its  diameter  and  the  thinness  of  its 
walls  should  be  so  considered.  In  the  aged, 
as  all  persons  are  not  afflicted  with  this  fragility, 
so  are  there  some  whose  bones  cannot  be  dis- 
tinguished from  those  of  the  healthy  adult. 
As  to  the  ordinary  characters  of  the  bones  of 
old  persons,  Mr.  Wilson  remarks  they  are 
never  found  so  friable  and  fragile  as  to  crumble 
like  a  calcined  bone,  but,  on  the  contrary,  they 
contain  a  large  quantity  of  oil;  and  when 
dried  after  death,  they  are  so  greasy  as  to  be 
unfit  to  be  preserved  as  preparations.  Their 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


442 

organized  vascular  part  is  diminished,  but  their 
oily  animal  matter  is  increased. 

Mollifies  ossium  is  a  disease,  the  phenomena 
of  which  are  directly  the  reverse  of  those  we 
have  just  considered.  In  fragilitas  the  bone 
snaps  across  from  the  most  trifling  causes  :  in 
mollities  it  is  flexible,  bends  in  every  direction, 
and,  of  course,  is  useless  for  the  purposes  of 
support  or  motion.  The  morbid  condition 
seems  to  arise  from  a  want  of  accordance  be- 
tween the  secreting  and  absorbing  vessels  of 
the  bones  affected :  if  the  earthy  material  is 
not  secreted  at  all  or  in  insufficient  quantity, 
or  if  it  is  absorbed  too  rapidly,  mollities  will 
be  the  consequence,  and  we  may  presume  that 
there  will  be  variety  in  the  rate  of  its  progress 
and  in  the  intensity  of  its  symptoms,  according 
to  the  degree  of  derangement  of  function  ex- 
isting at  different  times.  It  may  thus  be  easily 
comprehended  how  fragility  of  bone  may  be 
an  early  symptom  of  mollities,  at  a  period 
when  the  earthy  material  has  been  removed  to 
an  extent  which  renders  the  bone  completely 
flexible. 

Of  the  causes  that  produce  this  curious  dis- 
ease, or  of  the  change  of  structure  that  occurs 
at  an  early  period,  nothing  is  certainly  known, 
indeed,  it  is  so  rare  an  affection  that  little  oppor- 
tunity for  anatomical  or  chemical  examination 
in  any  of  its  stages  has  occurred.  Boyer 
seems  to  regret  our  deficiency  in  this  branch  of 
pathological  knowledge,  and  doubts  that  there 
are  a  sufficient  number  of  authentic  cases  to 
establish  such  a  difference  between  the  fragility 
and  the  softness  of  bone  as  to  authorize  them 
being  considered  distinct  diseases.  There  can 
be  no  doubt  that  in  the  cases  of  cancer,  &c. 
which  have  occasioned,  or  been  attended  by,  a 
softening  of  the  bones,  the  symptom  of  fra- 
gility has  been  observed  at  one  period  or 
another,  and  perhaps  there  is  no  such  thing  as 
a  softening  of  the  bones  independent  of  some 
malignant  taint  in  the  constitution.  "  There 
is  scarcely  any  case,"  observes  the  author  just 
quoted,  "  of  a  pure  and  simple  softening 
(ramollissement)  of  the  bones:"  not  one  (we 
believe)  in  which  they  have  been  found  merely 
deprived  of  their  earthy  constituent,  leaving 
the  animal  material  healthy  and  unaltered, 
like  a  bone  that  had  been  prepared  by  macera- 
tion in  muriatic  acid;  whilst  all  the  dissections 
of  mollities  exhibit  such  decided  alterations  of 
structure  as  to  justify  an  opinion  of  the  exis- 
tence of  some  malignant  disposition  in  the 
entire  system.  This  view  of  the  case  ought  to 
remove  the  disease  from  the  position  it  holds 
in  our  classification,  and  place  it  among  the 
derangements  of  structure,  only  that  there  is 
some  reason  for  supposing  that  the  first  and 
early  stages  may  be  accompanied  with  the 
absorption  of  the  phosphate  of  lime,  and  it 
must  therefore  signify  little  where  we  place  an 
affection,  of  the  nature  of  which  we  are  con- 
fessedly so  ignorant. 

There  is,  however,  a  softness  and  pliability 
of  bone  (we  use  the  word  softness  in  opposi- 
tion to  softening)  in  which  there  is  no  malig- 
nant tendency  whatever.  It  is  original  and 
congenital,  that  is,  from  birth  the  process  of 


ossification  is  suspended  in  some  part  or  limb. 
We  have  seen  two  instances  of  this  :  the  most 
remarkable  occurred  in  a  poor  man  forty  years 
of  age,  whose  right  arm  was  perfectly  flexible, 
and  of  course  powerless.  He  stated  that  he 
had  been  so  from  birth,  but  in  every  other  re- 
spect had  enjoyed  the  very  best  health;  he  earned 
his  livelihood  with  the  other  arm,  with  which 
he  had  become  wonderfully  dextrous.  On 
the  nature  of  the  cause  that  could  suspend  a 
particular  process  of  nutrition  in  one  limb,  the 
remainder  of  the  body  being  perfectly  healthy, 
it  would  be  useless  to  speculate  at  present. 

The  most  extraordinary  instance  of  mollities 
ossium  on  record  is  that  of  Madame  Supiot. 
It  may  be  found  at  length  detailed  by  Brom- 
field,  to  whom  it  was  communicated  by  M. 
Supe,  surgeon  to  the  hospital  of  La  Charite.* 
This  woman  appears  to  have  been  an  in- 
valid for  fifteen  years,  during  the  first  five  of 
which  she  suffered  from  great  weakness  in  her 
loins  and  lower  extremities,  accompanied  by 
great  pain,  which,  however,  did  not  prevent 
her  giving  birth  to  two  children  within  the 
time.  When  M.  Supe  saw  her,  "  the  trunk 
was  extremely  shortened,  and  did  not  exceed 
twenty-three  inches  in  length.  The  thorax 
was  exceedingly  ill-formed,  and  the  bones  of 
the  upper  extremity  were  greatly  distorted ; 
those  of  the  lower  were  very  much  bent ;  and 
the  thigh-bones  became  so  extremely  pliable 
as  to  permit  the  legs  to  be  turned  upwards, 
insomuch  that  her  feet  lay  on  each  side  of  her 
head.  The  softness  of  her  bones  daily  in- 
creased to  the  hour  of  her  death."  It  is  unne- 
cessary to  dwell  on  the  symptoms  under  which 
she  laboured,  as  it  must  be  obvious  that  no 
one  viscus  could  perform  its  function  properly 
in  such  an  extraordinary  mass  of  deformity  as 
she  eventually  became.  On  dissection,  M. 
Supe  says,  "  the  bones,  one  may  truly  say, 
had  arrived  at  the  utmost  degree  of  softness, 
as  we  have  not  heard  of  any  observations 
similar  to  this  case.  In  effect  we  have,  now 
and  then,  remarked  that  bones  become  mem- 
branous and  of  the  consistence  of  flesh,  but  I 
believe  there  never  was  before  seen  an  instance 
of  the  osseous  particles  in  the  great  bones  of 
the  extremities  being  so  totally  dissolved,  leav- 
ing no  more  than  the  form  of  a  cylinder  by 
the  periosteum  remaining  unhurt." 

Mr.  Goochf  relates  a  case  which  lasted  five 
years,  and  which  at  an  early  period  exhibited 
the  symptoms  of  fragility,  the  patient  having 
broken  her  leg  as  she  was  walking  from  the  bed 
to  her  chair  and  heard  the  bones  snap.  The 
winter  after  breaking  her  leg,  she  had  symptoms 
of  scurvy,  and  bled  much  at  the  gums,  and 
throughout  her  illness  her  legs  and  thighs  were 
cedematous,  and  subject  to  excoriate,  discharg- 
ing a  thin  yellow  ichor.  From  the  commence- 
ment of  the  attack  the  bones  continued  to  grow 
softer,  and  a  year  before  her  death  "  she 
breathed  with  difficulty,  and  the  thorax  ap- 
peared so  much  straitened  as  necessarily  to 

*  Bromfield's  Surg  ry,  vol.  iii.  p.  30. 
t  The   Chirurgical    Works  of   Benjamin  Gooch, 
vol.  ii.  p.  393. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


impede  the  expansion  of  the  lungs  :  her  spine 
was  much  distorted,  and  any  motion  of  the 
vertebrae  of  the  loins  excited  extreme  pain : 
her  legs  and  thighs  being  quite  useless,  she 
was  confined  to  her  bed  in  a  sitting  posture  : 
the  bones  she  rested  upon,  having  lost  their 
solidity,  were  much  spread,  and  the  ends  of 
her  fingers  and  thumbs,  by  frequent  efforts  to 
raise  herself,  were  become  very  broad,  with  a 
curvature  of  their  phalanges  :  she  now  mea- 
sured but  four  feet,  though  before  this  disease 
she  was  five  feet  and  a  half  high  and  well 
shaped."  After  death  she  was  found  wanting 
in  her  natural  stature  two  feet  and  two  inches. 

"  All  her  bones  except  her  teeth  were  more 
or  less  affected,  and  scarcely  any  would  resist 
the  knife :  those  of  the  head,  thorax,  spine, 
and  pelvis  were  nearly  of  the  same  degree  of 
softness;  those  of  the  lower  extremities  were 
much  more  dissolved  than  those  of  the  upper 
or  of  any  other  part ;  they  were  changed  into 
a  kind  of  parenchymatous  substance  like  soft 
dark-coloured  liver  without  the  least  offensive 
smell.  I  cut  through  the  whole  length  without 
turning  the  edge  of  the  knife,  and  found  less 
resistance  than  firm  muscular  flesh  would  have 
made,  meeting  only  here  and  there  with  bony 
laminae,  thin  as  an  egg-shell. 

"  Those  bones  were  most  dissolved  which 
in  their  natural  state  are  most  compact,  and 
contain  most  marrow  in  their  cavities.  This 
circumstance  may  appear  more  worthy  of  ob- 
servation as  it  held  throughout,  and  looks 
as  if  the  wonderful  change  they  had  undergone 
was  occasioned  by  the  marrow  having  acquired 
a  dissolving  quality ;  for  it  was  evident  the 
dissolution  began  internally  by  the  bony  laminae 
remaining  here  and  there  on  the  outside  and 
no  where  else,  and  the  pain  in  the  beginning 
of  the  disease  not  being  increased  by  external 
pressure." 

Mr.  Wilson*  met  with  three  cases,  of  one 
of  which  he  gives  the  dissection,  which  in 
some  respects  resembles  the  preceding.  As  it 
exhibited  the  symptom  of  fragility, — indeed  the 
symptoms  throughout  were  rather  such  as 
should  appertain  to  fragilitas  than  mollities, 
for  most  of  the  bones  of  the  skeleton  had  given 
way,  some  of  which  were  imperfectly  united, 
and  many  not  at  all, — as  the  bones  were  altered 
into  a  substance  not  very  unlike  that  described 
by  Gooch,  and  as  the  disease  evidently  com- 
menced within,  we  subjoin  an  extract  from 
the  dissection,  which  will  be  sufficient  without 
entering  into  the  more  minute  details. 

"  All  the  bones  were  diseased.  The  ossa 
brachiorum  were  so  soft  that  I  very  readily 
divided  them  with  a  common  scalpel  from  their 
heads  until  near  the  condyles.  Immediately 
at  the  condyles  both  bones  were  hard,  and  the 
articulating  cartilages  had  a  natural  healthy 
appearance ;  both  bones  had  been  fractured ; 
in  one  the  fracture  had  not  united,  and  in  the 
other  there  were  several  fractures  which  had 
united  very  imperfectly.  The  compact  sub- 
stance of  the  bone  was  in  some  places  not 

*  Wilson's  Lectures  on  the  Bones  and  Joints, 
p.  253. 


443 

thicker  than  an  egg-shell :  the  cancelli  were 
totally  destroyed,  and  the  cavities  in  the  mid- 
dle of  the  bones  were  filled  up  with  a  substance 
which  seemed  to  have  been  originally  extra- 
vasated  and  coagulated  blood,  but  which  had 
become  vascular,  and  had  much  oil  deposited 
in  the  cells  within  it.  These  substances  ap- 
peared to  have  produced  absorption  of  part  of 
the  bone  from  their  enlargement  and  internal 
pressure,  for  in  some  places  the  external  surface 
of  the  bone  was  removed  and  tumours  allowed 
to  extend  through  the  openings." 

In  confirmation  of  the  opinion  that  this 
disease  is  produced  by  some  malignant  taint  in 
the  constitution,  it  may  be  proper  to  add  that 
hitherto  it  has  baffled  every  mode  of  treatment. 
It  continues  its  progress  without  stop  or  inter- 
ruption, and  is  inevitably  fatal. 

Inflammation — osteitis. — The  exact  process 
that  is  carried  on  within  an  inflamed  part* 
seems  not  to  be  satisfactorily  understood,  al- 
though the  subject  has  exercised  the  ingenuity 
and  employed  the  research  of  many  who  have 
distinguished  themselves  in  the  cultivation  of 
pathological  science.  If  this  position  is  true 
with  regard  to  the  softer  and  more  external 
structures  which  are  open  to  examination  both 
by  the  touch  and  eye,  it  must  be  still  more  so 
with  reference  to  the  osseous  system,  the  parts 
of  which  are  more  or  less  deep-seated  and 
concealed  from  observation.  We  know,  how- 
ever, that  the  process  of  inflammation  is  greatly 
modified  by  the  structure  of  the  part  affected, 
or  perhaps  more  particularly  by  its  vascular 
organization,  some  powerfully  resisting  the 
inroads  of  disease,  and  repairing  its  ravages 
with  wonderful  activity,  while  others  exhibit 
as  remarkable  a  want  of  energy,  seem  scarcely 
capable  of  a  struggle,  and  run  at  once  into 
mortification.  But  as  the  bones,  besides  their 
animal  ingredients,  contain  an  earthy  material 
which  must  exert  considerable  influence  on  the 
phenomena,  the  progress,  and  the  results  of 
inflammation,  it  will  be  necessary  to  examine 
the  subject  with  reference  to  the  nature  of  the 
structure  particularly  affected. 

A  bone  in  its  healthy  condition  is  copiously 
supplied  with  bloodvessels. f  When  examined 
on  its  external  surface  stripped  of  its  perios- 
teum, it  exhibits  a  bluish-grey  colour,  evidently 
produced  by  a  quantity  of  blood  contained 
within  it.  When  it  is  cut,  or  when  the  perios- 
teum is  torn  from  it,  a  number  of  bloody 
specks  are  seen  ;  and  the  cancellated  structure 
in  which  the  marrow  is  lodged  is  always  red, 
particularly  in  young  subjects.  By  Mr.  How- 
ship's  observations  it  appears  that  "  the  small 
space  occupied  by  the  bloodvessels  of  the 
canals  (within  the  bones)  compared  with  that 
which  is  found  to  be  allotted  to  the  secretions 
and  membranes  of  these  cavities,  distinctly 
proves  that  the  circulation  must,  under  all 
circumstances,  enjoy  as  much  freedom  here  as 
elsewhere ;  and  the  intimate  connexion  formed 
by  these  canals  between  all  parts  of  the  bones 

*  Generally  spoken  of  as  the  proximate  cause  of 
inflammation. 

t  See  Howship's  Papers  in  the  Medico-Chirurgi- 
cal  Transactions. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


444 

and  the  surrounding  soft  parts  affords  the 
strongest  grounds  for  believing  that  the  minute 
vascular  and  membranous  organization  of  the 
bones  is  as  susceptible  of  impressions  from 
irritation  or  sympathy  as  the  muscular,  glandu- 
lar, or  other  soft  structures  of  the  body."  The 
bones  in  common  with  other  parts  are  conse- 
quently subject  to  inflammation  with  all  its 
consequences  of  adhesion,  suppuration,  granu- 
lation, ulceration,  &c.  &c.,  but  subject  to  the 
following  modifications  which  result  from  the 
peculiarities  of  structure  and  material  compo- 
sition indicated,  and  the  intimate  connexion 
just  alluded  to  between  them  and  the  adjacent 
soft  parts. 

1.  The  connexion  between   the   bone    and 
periosteum  is  so  complete  that  it  is  not  easy  to 
conceive  how  inflammation  of  a  bone  can  occur 
without  its  membranes  being  more  or  less  en- 
gaged, and  therefore  it  is  difficult  to  meet  with 
a  case  of  diseased   bone  unaccompanied  by 
periostitis. 

2.  The  effects  of  inflammation  on  the  mem- 
brane and  on  the  bone  must  be  different.    One 
structure  can  swell,  the  other  in  the  first  in- 
stance cannot;  and  hence  the  vessels  of  the 
bone  itself  in  a  state  of  debility  and  compressed 
by  an  unyielding  substance  are  very  liable  to 
die,  whilst  those  of  the  periosteum  tumefy  and 
exhibit    a    more    mitigated   form   of  disease. 
Thus  the  periosteum  in  inflammation  is  gene- 
rally found  swollen  or  thickened,  and  detached 
from  the  bone  underneath,  which  is  then  usually 
either  carious  or  necrosed. 

3.  Those  bones  or  parts  of  bones  which  are 
hardest  and  firmest  usually  die  soonest,  whence 
Mr.  Wilson's  remark  that  "  they  are  the  soonest 
cured,"  the  process  of  exfoliation  being  set  up 
by  the  surrounding   living  parts   in  order  to 
remove  that  which  is  dead. 

4.  In  the  various  processes  of  repair  and  re- 
production the  periosteum  largely  participates, 
and  if  this  latter  membrane  has  been  injured 
or  torn  off,  the  vessels  of  the  adjacent  cellular 
tissue  seem  to  assume  a  new  function  in  order 
to  supply  its  place.     Thus,  if  a  portion  of  the 
scalp  is  torn  down,  leaving  the  cranium  per- 
fectly denuded,  it  by  no  means  follows  that 
the  bone  must  exfoliate  if  the  flap  has  been 
carefully   laid   down    and    still  preserves    its 
vitality ;  but  perhaps  the  best  illustration  may 
be  drawn  from  some  cases  of  necrosis  succeed- 
ing to  injuries  by  which  the  periosteum  had 
been  removed,  in  which  the  process  of  regene- 
ration is  commenced  and  completed  notwith- 
standing. 

Thus  far,  then,  we  have  seen  that  there  is  little 
difference  between  the  inflammatory  process  in 
bone  and  in  any  other  structure  of  similar  or 
equal  vascular  organization ;  the  chief  or  cha- 
racteristic peculiarities  must  therefore  depend 
on  the  presence  of  the  earthy  material,  which 
we  shall  find  influencing  the  phenomena  of 
the  disease,  but  perhaps  more  especially  its 
progress.  Thus,  whether  the  operation  is  sana- 
tive or  otherwise — whether  adhesion  is  to  be 
accomplished,  ulceration  or  granulation  is  to 
be  set  up,  or  a  spoiled  or  dead  portion  of  bone 
is  to  be  removed — the  progress  of  the  work  is 


more  sluggish,  and  its  ultimate  accomplishment 
deferred  to  a  much  later  period,  than  in  any 
other  animal  structure.  When  a  bone  is  wound- 
ed, coagulating  lymph  is  thrown  out  as  quickly 
and  with  as  much  facility  as  from  any  other 
tissue,  but  nothing  can  be  more  familiarly 
known  than  that  it  will  require  a  length  of  time 
before  consolidation  is  effected,  and  the  solution 
of  continuity  is  repaired. 

The  process  of  ulcerative  absorption  in  any 
structure  is  scarcely  understood  either  as  to  the 
stimulus  which  first  determines  the  vessels  to 
this  action  or  their  modus  operand!  subse- 
quently; still  less  can  we  comprehend  how  a 
solid  unorganized  material  like  the  earthy  phos- 
phate of  bone  comes  to  be  thus  removed. 
That  this  process  is  not  performed  with  the 
same  facility  as  in  softer  structures  of  equal  or 
inferior  vascularity  is  obvious  from  the  tedious- 
ness  of  its  progress,  a  delay  that  is  therefore 
attributable  to  the  presence  of  this  earthy  sub- 
stance. The  absorption  of  the  earthy  particles 
takes  place  under  two  different  conditions;  one 
without  the  secretion  of  purulent  matter  (dry 
caries),  examples  of  which  may  be  seen  in  the 
caries  of  bones  compressed  by  aneurismal  tu- 
mours, and  in  some  cases  of  angular  curvature 
of  the  spine.  It  is  of  importance  to  remark 
this  kind  of  caries,  and  to  observe  that  its  pro- 
gress is  equally  or  perhaps  more  rapid  than 
that  in  which  purulent  matter  is  secreted. 
Many  writers  have  assumed  that  pus  possessed 
a  solvent  quality,  and  by  thus  preparing  the 
ossific  matter  for  absorption,  materially  assisted 
in.  the  process — an  idea  which  the  preceding 
observation  strongly  militates  against.  In  the 
other  there  is  a  secretion  of  purulent  matter, 
and  the  case  is  analogous  to  suppuration  and 
ulceration  in  the  softer  tissues,  except  that  the 
process  is  still  very  slow,  and  in  general  the 
odour  of  the  matter  is  very  offensive. 

Adhesion.*  Formation  of  callus. — The  phe- 
nomena attendant  on  this  process  are  most 
easily  and  familiarly  observed  in  the  re-union 
of  fractures.  It  is  very  remarkable,  however, 
that  considering  the  number  of  celebrated  men 
who  have  directed  their  attention  to  this  subject, 
and  the  opportunities  for  observation  that  are 
so  constantly  occurring,  nothing  has  yet  been 
positively  determined.  We  have  theories  in 
abundance,  apparently  founded  on  and  sup- 
ported by  experiment,  but  still  so  contradictory 
that  it  is  impossible  not  to  entertain  a  suspicion 
that  the  theories  were  in  general  formed  in  the 
first  instance,  and  the  facts,  if  they  did  not 
immediately  apply,  wrested  a  little  in  order  to 
support  them  afterwards.  Hence  this  part  of 
our  pathological  studies  consists  of  little  more 
than  a  history  of  opinions  and  doctrines  neces- 
sary to  be  known  as  constituting  part  of  the 
literature  of  the  profession,  but  totally  unavail- 
able to  any  practical  purpose. 

The  most  ancient  explanation  of  the  process 
by  which  callus  is  formed  is,  that  it  was  per- 
fected by  means  of  a  viscous  fluid  poured  out, 
around  and  between  the  fragments  of  a  divided 
bone,  which  were  thus  mechanically  glued  to- 

*  The  adhesive  ossific  inflammation  of  Hunler. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


445 


gether.  This  fluid,  which  was  termed  the  osse- 
ous juice,  was  supposed  to  acquire  the  requi- 
site consistence  afterwards,  and  thus  became 
the  medium  of  a  firm  union.  Nothing,  how- 
ever, was  said  of  the  time  or  manner  in  which 
the  consolidation  was  effected,  nor  of  the 
absorption  of  the  superabundant  part  of  this 
fluid  subsequently. 

The  first  who  doubted  this  theory  of  the 
osseous  juice,  or  rather  who  thought  it  insuffi- 
cient, was  Duhamel,  a  man  of  extraordinary 
ingenuity,  but  unfortunately  not  a  physician, 
and  therefore  not  qualified  to  examine  or  to 
explain  the  results  of  vital  actions.  lie  adopted 
his  ideas  as  to  the  formation  and  growth  of 
bone  analogically  from  trees  and  vegetables, 
and  supposing  the  periosteum  to  answer  the 
same  purpose  to  bone  that  the  bark  did  to  the 
wood,  he  conceived  that  ossification  went  for- 
ward by  the  conversion  of  the  internal  layer  of 
periosteum  into  bone.  It  was  natural,  having 
formed  this  theory  as  to  the  original  conforma- 
tion, to  advance  it  still  farther  into  an  explana- 
tion of  the  mode  of  re-union  in  fracture.  He 
said  that  the  extremities  of  the  torn  periosteum 
covering  the  fragments  swelled  ;  that  they  met, 
and  uniting,  formed  a  kind  of  brace  or  ferule 
inside  and  outside  of  the  fracture;  sometimes, 
in  case  of  the  external  membrane  being  torn 
off,  the  internal  answered  every  purpose  alone; 
sometimes  the  external  periosteum  was  suffi- 
cient, but  in  every  case  it  was  this  that  perfected 
the  operation.  It  is  needless  now  to  canvass 
a  theory  that  has  long  since  been  given  up  as 
untenable,  yet  as  if  to  show  how  little  of 
novelty  can  be  expected  in  physiological  rea- 
soning, it  will  be  found  that  an  opinion  not 
very  far  removed  from  this  in  its  bearings  was 
the  one  entertained  by  Dupuytren,  so  recently 
lost  to  science. 

The  next  opinion  to  be  noticed  is  that  of 
Haller.  This  great  physiologist,  who  was  a 
cotemporary  of  Duhamel,*  quite  dissatisfied 
with  the  ideas  entertained  in  his  time  on  this 
subject,  endeavoured  to  develope  the  truth  by 
experiments,  and  conducted  many,  in  conjunc- 
tion with  a  pupil  of  his  named  Dethlef.  The 
result  was,  that  the  process  of  re-union  ap- 
peared to  him  to  be  the  same  as  that  of  the 
original  ossification;  1st,  that  a  gelatinous  or 
gluey  substance  is  poured  out  around  the  ends 
of  the  fragments;  2d,  that  this  substance  be- 
comes converted  into  genuine  cartilage;  and 
lastly,  that  an  osseous  deposit  is  laid  down  in 
the  cartilage,  forms  a  ring  of  bone,  and  gra- 
dually increases  until  the  entire  ossification  is 
completed.  This  theory  is  principally  objec- 
tionable in  the  regularity  with  which  these 
changes  are  said  to  take  place,  whereas  it  is 
more  than  questionable  whether  this  gelatinous 
fluid,  the  origin  of  the  callus,  ever  becomes  car- 
tilage at  all.  Doubtless  it  is  altered  in  con- 
sistence and  becomes  hard  and  firm,  opaque 
and  elastic,  and  thus  far  resembles  cartilage  in 
its  sensible  qualities;!  but  it  is  tinged  of  a  red 

*  Haller  was  born  a  short  time  after  Duhamel, 
and  died  before  him,  this  latter  philosopher  having 
attained  the  age  of  82. 

t  Macdonald. 


colour  by  feeding  the  animal  with  madder, 
which  is  not  the  case  with  cartilage ;  and  che- 
mical analysis  shews  its  nature  to  be  osseous 
and  not  cartilaginous.  However,  the  experi- 
ments of  Haller  and  Dethlef  are  entitled  to 
great  attention  from  the  care  with  which  they 
were  conducted,  and  with  a  little  modification 
their  results  are  probably  not  very  remote  from 
truth. 

Hunter,  so  happy  in  the  doctrine  of  adhe- 
sion, endeavoured  to  extend  it  as  widely  as 
possible,  and  has  certainly  simplified  both  our 
notions  with  respect  to  divided  parts  and  our 
practice  in  procuring  union,  although  his  cor- 
rectness in  considering  effused  blood  to  be  the 
medium  of  that  union  has  been  frequently 
doubted.  According  to  him,  the  first  effect  of 
fracture  is,  the  effusion  of  blood  from  the 
ruptured  vessels  of  the  bone  and  the  adjacent 
structures:  this  blood  becomes  organised  by 
vessels  shooting  into  it ;  whilst  in  the  mean 
time  the  ends  of  the  fragments  inflame,  and 
this  inflammation  produces  adhesion  in  the 
surfaces  that  are  even,  and  a  disposition  in  the 
scales  or  points  of  the  broken  edges  that  re- 
main, to  be  removed  by  absorption.  Pretty 
nearly  the  same  are  the  conclusions  to  which 
Mr.  Howship  arrived  after  a  series  of  expe- 
riments conducted  with  great  accuracy  and 
minuteness.  This  paper  is  in  the  ninth  volume 
of  the  Medico-Chirurgical  Transactions,  in 
which  these  experiments  (performed  on  the 
fractured  bones  of  rabbits)  are  detailed  and 
illustrated  with  engravings.  They  refer  to  the 
appearances  observed  on  the  third  day,  on  the 
fifth,  the  ninth,  the  fifteenth,  the  twenty-third, 
and  thirty-second  days  after  the  fracture.  The 
relation  of  these  experiments  singly  would 
occupy  more  space  than  can  be  appropriated  to 
this  part  of  the  subject,  and  we  must  therefore 
confine  ourselves  to  the  conclusions  as  drawn 
from  them  by  the  author  himself.  He  concludes 
that  the  first  effect  of  fracture  is  extravasation 
of  blood  into  the  surrounding  cellular  struc- 
tures, principally  that  of  the  periosteum  ;  into 
the  medullary  cavities  of  both  fragments  and 
between  their  fractured  extremities.  This  blood 
soon  coagulates ;  after  some  further  time  its 
colouring  matter  disappears ;  and  the  thick- 
ened periosteum  becoming  more  firm  assumes 
the  sensible  characters  of  cartilage.  The  de- 
position of  osseous  matter  takes  place  within 
the  coagulum,  beginning  at  the  part  nearest  the 
fracture  and  extending  gradually  from  this 
point:  it  even  commences  in  the  clot  situated 
within  the  medullary  cavity  before  the  colour- 
ing matter  is  removed ;  but  under  every  cir- 
cumstance and  in  every  situation,  we  are  to 
understand  that  the  coagulum  of  blood  is  the 
nidus  of  ossification  and  the  medium  of  union 
between  the  fragments.  Notwithstanding  the 
respect  due  to  such  high  authority,  there  are 
many  who  do  not  believe  in  the  possibility  of 
effused  blood  becoming  organised,  and  look 
with  doubt  and  suspicion  on  every  experiment 
and  every  observation  by  which  such  a  doc- 
trine is  sought  to  be  established.  They  reason, 
that  if,  under  any  circumstances,  blood  became 
the  medium  of  union,  we  ought  to  leave  the 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


446 


surface  of  a  stump  or  other  wound  covered 
with  clotted  blood,  and  spare  ourselves  all  the 
labour  and  pains  we  employ  in  removing  it 
and  placing  the  cut  surfaces  cleanly  in  appo- 
sition with  each  other.  And  they  also  remark 
that  when  a  clot  of  blood  is  left  behind,  how 
very  commonly,  instead  of  becoming  organised, 
it  lies  as  a  dead  substance  in  the  wound,  im- 
pedes the  union,  promotes  suppuration,  and 
imparts  to  the  discharge  a  putrid  and  offensive 
odour.  These  pathologists  suppose  that  in 
many  instances  the  fi  brine  of  the  blood  has 
been  mistaken  for  coagulating  lymph,  which 
is  the  natural  product  of  the  vessels  in  the 
adhesive  stage  of  inflammation,  is  capable  of 
becoming  organised,  and  ought  to  be  the  legi- 
timate seat  of  any  deposit  to  be  afterwards 
laid  down  in  completing  the  process  of  union. 

We  now  pass  to  the  theory  of  Bordenave, 
Bichat,  and  Richerand,  who  make  the  union 
of  fractures  analogous  to  that  of  the  soft  parts 
by  the  second  intention,  or  by  means  of 'granu- 
lation. Like  other  pathologists,  they  have 
supported  their  opinions  by  observation  and 
experiment;  and  without  'entering  into  the 
minuter  circumstances  connected  with  this  hy- 
pothesis, it  will  be  necessary  to  mention  some 
very  familiar  facts  that  bear  upon  the  case. 
In  necrosis,  the  surface  of  the  new  or  grow- 
ing bone  is  often  seen  covered  with  granu- 
lations. In  cases  of  amputation,  when  the 
bone  protrudes  after  eight  or  ten  days,  the  cut 
extremity  is  observed  to  be  fungoid  and  granu- 
lated. And  in  some  cases  of  compound  frac- 
ture we  can  observe  the  process  of  granulation 
going  forward,  and  actually  see  that  it  is  thus 
the  union  is  completed.  It  nevertheless  ap- 
pears very  doubtful  whether  granulation  has 
any  part  in  the  process  of  uniting  a  fracture, 
unless  where  a  communication  exists  between 
the  broken  ends  of  the  fragments  and  the  ex- 
ternal air.  In  a  compound  fracture,  or  in  the 
case  of  a  bone  protruding  from  a  stump,  there 
will  be  granulations,  often  to  a  degree  of 
excessive  exuberance;  and  in  them  there  will 
be  a  deposit  of  osseous  substance,  because 
new  structures  always  assume  to  a  certain 
extent  the  nature  of  the  parts  from  which  they 
are  produced  ;  but  in  a  case  of  simple  fracture, 
where  there  is  no  wound,  no  communication 
with  the  atmosphere,  and  not  a  single  drop 
of  purulent  matter  is  formed,  it  is  very  doubt- 
ful whether  granulations  could  exist;  at  least 
their  existence  has  never  been  demonstrated. 

Amongst  modern  pathologists,  Meckel's*  opi- 
nion is  entitled  to  very  great  respect,  although 
we  may  not  be  disposed  to  accede  implicitly 
to  his  views.  He  ranks  among  those  who 
consider  the  process  of  consolidation  in  frac- 
ture to  be  similar  to  that  of  original  ossi- 
fication, and  states,  that  at  first  there  is  an 
effusion  of  a  gelatinous  substance  which  gra- 
dually becomes  firmer  and  more  solid  in  con- 
sistence, and  is  converted  into  cartilage,  in  the 
interior  of  which  osseous  nuclei  appear  that 
join  to  each  other  and  to  the  broken  ends  of 
the  bone,  and  also  envelope  any  fragments  that 

*  Manuel  d'Anatomie,  torn.  i.  p.  335. 


may  have  been  detached.  At  the  same  time 
the  spiculae  or  scales  become  rounded  off  in 
order  that  the  surrounding  parts  may  not  suffer 
injury  or  irritation.  It  is  not  necessary  to  the 
perfection  of  this  union  that  the  ends  of  the 
fragments  should  be  accurately  in  contact: 
it  is  sufficient  if  they  lie  against  each  other, 
and  then  the  union  occurs  by  the  same  means, 
and  exactly  on  the  principle  of  anchylosis 
taking  place  between  different  bones.  It  must 
be  understood  that  this  ossific  deposit  is  laid 
down  both  external  to  and  within  the  bone ; 
that  when  union  is  complete,  the  bone  is  di- 
vided into  two  cavities  internally ;  and  that, 
for  a  length  of  time  afterwards  or  for  ever, 
it  may  be  known,  by  making  a  longitudinal 
section,  whether  a  bone  had  ever  been  broken 
or  not.  He  further  states  that  the  part  sur- 
rounded and  joined  by  ossified  callus  is 
stronger  and  firmer  than  any  other,  and  to  all 
appearance  this  observation  is  correct,  but  it  is 
contrary  to  one  of  Mr.  Howship's  experiments, 
who  saw  the  callus  break  down  and  crumble 
away  in  an  attempt  to  calcine  it,  and  therefore 
concluded  that  it  was  softer  and  more  highly 
animalized. 

Hitherto  we  have  noticed  a  number  of  the- 
ories, all  of  which,  with  the  exception  of  that 
of  Duhamel,  bear  a  strong  similarity  to  each 
other,  the  principal  points  of  difference  being, 
1.  as  to  whether  the  soft  gelatinous  substance, 
which  all  agree  in  having  seen,  was  the  fibrine 
of  the  blood  deprived  of  its  colouring  matter, 
or  genuine  coagulating  lymph  effused  by  in- 
flamed vessels :  2.  whether  this  in  process  of 
time  was  changed  into  real  cartilage,  or  the 
osseous  deposition  took  place  into  this  lymph 
very  much  inspissated :  and,  3.  whether  any- 
thing like  adhesion  happened,  or  the  conso- 
lidation was  perfected  after  the  manner  of 
union  by  the  second  intention,  namely,  by 
granulation.  We  now  proceed  to  take  a  view 
of  a  new  theory  bearing  some  resemblance  to 
that  of  Duhamel,  and  supported  by  the  autho- 
rity of  Dupuytren.  He  supposes  that  there 
are  two  distinct  and  different  processes  in  the 
union  of  bone.  First,  that  there  is  a  callus 
formed  like  a  brace  or  ferule  round  the  frag- 
ments externally,  with  a  plug  of  the  same 
material  within,  the  object  of  this  provision 
being,  to  hold  the  ends  of  the  fracture  in  ap- 
position whilst  the  union  that  is  to  be  per- 
manent is  going  forward :  thus  we  are  to 
imagine  a  kind  of  natural  splint  placed  around 
and  within  the  fractured  pieces  in  order  to 
preserve  them  in  situ.  This  preliminary  pro- 
cess commences  almost  immediately  after  the 
accident,  and  is  completed  in  the  space  of 
from  four  to  six  weeks.  Matters  remain  thus, 
while  the  ends  of  the  bones  are  becoming  per- 
manently united,  which  they  are  in  about  eight 
months,  during  the  latter  period  of  which  time 
the  mass  of  new  material  is  declining  in  size, 
and  is  eventually  removed  so  as  to  leave  the 
bone  of  its  natural  extent  and  figure.  The 
formation  of  this  first  callus,  which  he  calls 
"  cal  provisoire,"  is  attributed  to  the  perios- 
teum and  occasionally  to  all  the  surrounding 
structures,  and  in  the  centre  of  it  he  sup- 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


poses  the  fracture  to  remain  for  a  considerable 
time  un-united,  the  limb  being,  of  course, 
weaker  here,  so  that,  in  the  event  of  the  occur- 
rence of  a  new  fracture,  this  will  be  the  spot 
in  which  it  will  give  way.  The  second  or  per- 
manent callus,  which  he  calls  "  cal  definitif," 
is  the  actual  medium  of  union  between  the 
fragments,  and  remains  like  the  cicatrix  of  a 
wound  in  the  soft  parts. 

It  must  appear  curious  to  the  reader  that  no 
positive  conclusion  should  have  been  obtained 
on  a  point  which  has  occasioned  so  much 
inquiry,  and  which  apparently  was  so  easy  of 
determination.  It  is  open  to  experiment; 
obvious  to  the  senses;  and  there  are  few 
sources  of  fallacy  except  such  as  might  arise 
from  previously  adopted  views  of  the  expe- 
rimentalist, and  perhaps  from  different  periods 
puring  the  progress  of  ossification  being  chosen 
for  making  the  observations,  and  the  same 
thing,  of  course,  being  seen  under  different 
circumstances.  We  think  it  might  have  been 
reasonably  suspected  from  analogy,  (and  the 
experiments  of  Breschet  and  Villerme  have 
confirmed  the  idea,)  that  nature,  in  the  sim- 
plicity of  her  operations,  produced  every  where 
similar  effects  from  similar  causes,  and  that, 
in  whatever  manner  the  re-union  of  divided 
soft  parts  was  accomplished,  the  same  would 
hold  good  as  to  bone,  only  allowing  a  longer 
time  in  order  to  admit  of  the  consolidation  of 
the  lymph  by  osseous  deposition.  And  such 
is  probably  the  fact.  In  an  incredibly  short 
space  of  time  after  the  receipt  of  a  fracture, 
the  process  of  repair  seems  to  be  actively  com- 
menced :  coagulating  lymph  is  effused  in  con- 
siderable quantity,  probably  mixed  with  blood, 
as  the  coagulum  is  found  to  possess  a  more 
than  ordinary  firmness  and  consistence.  At 
the  end  of  the  second  day  the  torn  edges  of 
the  periosteum  are  evidently  thickened,  pulpy, 
and  vascular,  easily  receiving  coloured  in- 
jections. At  the  end  of  the  fourth  day,  we 
have  seen  the  sharp  edge  of  the  fracture  be- 
ginning to  be  rounded  off.  Where  the  surfaces 
of  the  fragments  are  broad  and  thick,  it  is  easy 
to  observe  them  coated  with  a  deep  layer  of 
lymph, which  adheres  to  them  tenaciously  from 
a  very  early  period.  If  the  fragments  are  in 
apposition,  the  torn  extremities  of  the  peri- 
osteum are  united  by  the  intervention  of  this 
lymph,  the  membrane  appears  greatly  thick- 
ened also,  and  seems  to  afford  a  kind  of  pro- 
tection to  the  fracture ;  or,  otherwise,  an  im- 
mense and  irregular  mass  of  lymph  is  thrown 
out  around  both  fragments,  filling  up  all  the 
space  that  has  been  occasioned  by  the  dis- 
placement of  the  bones  and  the  laceration  of 
the  soft  parts.  In  effecting  this  deposition,  all 
the  vessels  of  the  part,  those  of  the  bone, 
periosteum,  and  adjacent  structures,  seem  to 
be  equally  engaged.  In  process  of  time  this 
lymph  becomes  organised,  assumes  a  ligamen- 
tous  rather  than  a  cartilaginous  appearance, 
although,  strictly  speaking,  the  new  structure 
possesses  not  the  true  characters  of  either,  and 
finally  is  converted  into  bone  by  the  simul- 
taneous establishment  of  numerous  but  irre- 
gular specks  of  ossification.  This  process 


447 

varies  as  to  the  time  required  for  its  com- 
pletion according  to  a  number  of  circum- 
stances, such  as  the  situation  of  the  bone,  the 
part  of  it  broken,  the  apposition  of  the  frag- 
ments, rest,  and  many  others  that  need  not  be 
enumerated  here  ;  as  well  as  the  age  and  con- 
stitution of  the  patient,  which  exert  such 
marked  influence  on  all  cases,  that  it  is  im- 
possible to  lay  down  certain  rules  for  calcu- 
lating the  time  that  may  be  required  for  the 
union  of  any  given  fracture. 

The  process  of  re-union,  however,  is  some- 
times very  imperfectly  performed;  sometimes 
it  is  suspended  indefinitely,  and  occasionally 
it  is  not  performed  at  all.  Of  the  causes  that 
occasion  these  deviations  from  the  natural  and 
usual  progress  of  ossific  union  we  are  in  ge- 
neral ignorant,  although  there  are  many  cases 
in  which  former  experience  may  enable  us  to 
predict  the  occurrence  of  such  an  event.  It 
has  been  already  stated  that  the  diseases  which 
occasion  a  fragility  of  bone  will  be  likely  to 
interfere  with  its  subsequent  union,  and  in 
these  cases  little  more  is  accomplished  than  the 
removal  of  the  sharp  spiculated  edges  by  ab- 
sorption :  the  presence  of  such  a  constitutional 
derangement  as  would  occasion  a  bone  to  give 
way  in  the  effort  to  turn  in  bed  will  be  suf- 
ficient to  explain  its  want  of  re-union.  But 
these  are  not  the  cases  generally  met  with. 
When  there  is  an  un-united  fracture,  or  as  it 
has  been  termed,  a  false  joint,  the  ends  of  the 
fragments  are  not  smooth  and  polished  moving 
on  each  other  like  articulated  surfaces,  but  are 
joined  together  by  the  intervention  of  a  liga- 
men to-cartilaginous  substance,  which,  accord- 
ing to  its  extent,  is  more  or  less  flexible,  and 
of  course  incapacitates  the  bone  from  the  per- 
formance of  its  functions  of  support  and  mo- 
tion. This  imperfect  union  occurs  in  some 
bones  with  wonderful  regularity ;  we  may,  for 
instance,  calculate  on  such  an  event  in  frac- 
tures of  the  neck  of  the  thigh,  and  in  the  trans- 
verse fracture  of  the  olecranon  and  patella ; 
but  it  happens  at  other  times  quite  unexpect- 
edly, iu  cases  wherein  we  could  suspect  no 
possible  cause,  in  which  there  may  have  been 
no  neglect,  no  impropriety  of  treatment,  to 
lead  to  such  a  result.  We  have  lately  seen 
two  cases  of  fractured  femur  remain  un-united 
at  the  end  of  five  and  six  months  in  the  per- 
sons of  fine  and  apparently  healthy  young 
men,  although  the  ends  of  the  bones  were  kept 
in  apposition,  and  in  every  other  respect  the 
treatment  was  correct. 

The  chief  causes*  to  which  this  imperfect 
union  has  been  attributed  are  a  removal,  or 
rather  a  withdrawing  of  the  broken  surface  of 
one  fragment  from  the  other,  a  want  of  vascu- 
larity  in  one  of  the  fragments,  and  the  fracture 
not  being  maintained  in  a  state  of  uninter- 
rupted repose. 

The  frequency  of  this  occurrence  in  fractures 
of  the  above-mentioned  bones,  in  which  the 
fragments  are  always  withdrawn  from  each 
other,  was  too  remarkable  not  to  lead  to  the 
connexion  of  the  circumstances  as  cause  and 

*  Sir  A.  Cooper  on  Dislocations  and  Fractures. 


448 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


effect,  the  only  objection  being  that  the  result 
is  not  uniform  and  universal.  Fractures  have 
been  submitted  to  each  of  the  above  con- 
ditions, more  especially  to  the  maintenance  of 
exact  co-aptation  for  months,  yet  has  no 
ossific  union  been  produced  ;  and  again  a  firm 
consolidation  has  taken  place  between  two 
bones,  the  extremities  of  which  had  been 
sawed  off  and  the  parts  placed  under  circum- 
stances that  could  not  permit  of  the  approxima- 
tion of  the  divided  surfaces.  We  have  a  case 
published  as  having  occurred  in  the  hospital 
of  La  Charite  in  Paris,  in  which  the  os  calcis 
was  broken ;  and  although  the  surfaces  of  the 
fragments  were  never  completely  separated, 
yet  the  usual  kind  of  ligamentous  connexion 
took  place ;  and  for  proof  that  a  solid  union 
may  occur  under  the  circumstances  above- 
stated,  we  refer  our  readers  to  Mr.  Crampton's 
second  case  of  extirpation  of  the  knee-joint.* 

If  we  can  subscribe  to  Larrey's  opinion  that 
only  the  vessels  of  the  bone  itself  can  minister 
to  osseous  union,  and  that  those  of  the  peri- 
osteum and  adjacent  structures  are  incom- 
petent to  such  function,  (an  opinion  in  which 
he  is  to  a  certain  extent  supported  by  Mr. 
Liston,f)  it  is  obvious  that  a  union  between 
fragments  at  a  distance  from  each  other  would 
be  difficult  if  not  impossible.  Here,  however, 
as  well  as  in  every  other  part  of  the  history 
of  ossific  union,  it  is  only  conjecture.  We 
have  nothing  like  substantial  definite  proof, 
and  must  only  rest  satisfied  with  a  knowledge 
of  the  fact  without"  being  able  to  explain  it, 
that  the  medium  of  union  between  fragments, 
the  faces  of  which  are  withdrawn  from  each 
other,  is  in  general  not  osseous. 

Whatever  may  be  the  operation  of  this  cause, 
that  of  the  other  two  is  by  no  means  so  ob- 
vious. The  second  J  has  been  generally  ad- 
duced in  explanation  of  the  non-union  of 
fractures  of  the  neck  of  the  thigh-bone,  but 
perhaps  without  being  entitled  to  the  impor- 
tance that  has  been  attached  to  it.  If  a  part 
is  only  possessed  of  a  degree  of  organisation 
barely  sufficient  to  preserve  its  vitality  in  ordi- 
nary circumstances,  but  inadequate  to  accom- 
plish any  process  of  repair,  it  should  follow 
that  any  violence  offered  to  it  ought  to  cause 
its  death,  or  at  least  its  removal  by  the  ab- 
sorbents, and  in  such  case  the  caries  or  exfo- 
liation of  a  fragment  of  bone  might  be  easily 
understood.  But  these  are  not  the  results  of 
fracture  of  the  neck  of  the  femur  except  in 
very  rare  and  anomalous  cases ;  and,  on  the 
contrary,  there  is  scarcely  an  example  of  exami- 
nation after  death  that  did  not  exhibit  a  conside- 
rable display  of  reparative  energy,  although  the 
results  were  not  such  as  to  produce  ossific  union. 
Professor  Colles§  has  published  twelve  cases 
of  post-mortem  examinations  of  this  accident, 
in  some  of  which  he  observed  the  appearance 
of  ivory-like  patches  on  the  surface  of  the 
superior  fragment,  evidently  proving  the  ex- 

*  Dublin  Hospital  Reports,  vol.  iv.  p.  236. 

t  Elements  of  Surgery. 

t  Cooper's  Surgical  Essays. 

§  Dublin  Hospital  Reports,  vol.  ii.  p.  334. 


istence  of  considerable  ossific  powers  in  this 
part.  Besides,  this  condition  of  the  head  of 
the  bone  has  been  assumed  rather  than  proved. 
On  the  most  attentive  examination,  we  have  not 
been  able  to  observe  any  deficiency  of  vascu- 
larity  within  it;  and  if  there  is  any  difference 
between  the  head  and  neck  and  shaft,  we  are 
rather  disposed  to  believe  the  hfcad  to  be  pos- 
sessed of  the  highest  degree  of  organization. 

The  advantage  of  the  most  absolute  rest  to  the 
cure  of  fracture^  has  been  observed  in  all  ages, 
and  yet  is  it  doubtful  how  far  its  influence  on 
the  question  under  consideration  can  be  appre- 
ciated. Few  fractures  can  be  kept  in  a  more 
perfect  state  of  repose  than  those  of  the  patella 
or  of  the  heel,  yet  the  union  in  both  these 
cases  is  always  ligamentous.  It  would  appear 
as  if  constant  although  very  trifling  motion 
was  more  prejudicial  than  occasional  shocks 
however  rude  and  productive  of  greater  dis- 
turbance, and  this  perhaps  is  the  reason  why 
false  joints  so  frequently  occur  after  fractures 
of  the  clavicle,  even  although  the  fragments 
have  never  suffered  displacement,  as  occurs 
when  the  bone  is  broken  near  its  acromial 
extremity. 

Suppuration  may  occur  in  the  osseous  tissue 
under  a  variety  of  conditions,  as  to  situation, 
as  to  the  character  of  the  matter,  and  as  to 
whether  it  is  produced  by  or  connected  with 
any  constitutional  or  specific  taint.  Pus  is 
occasionally,  though  not  frequently  contained 
in  a  cyst  or  sac  within  a  bone,  as  the  result  of 
inflammation,  and  resembling  the  common  ab- 
scess in  the  soft  parts.  These  collections  are 
never  very  large ;  they  are  usually  situated  in 
the  thick  and  spongy  parts  of  the  bones,  and 
have  a  strong  tendency  to  burst  into  the  neigh- 
bouring joint.  We  have  seen  a  case  of  abscess 
in  the  head  of  the  tibia,  which  appeared  to 
have  opened  into  the  knee-joint  even  after  it 
had  burst  externally.  The  disease  had  pre- 
viously existed  for  months,  the  patient  suf- 
fering very  little  either  locally  or  constitutionally 
until  the  communication  with  the  cavity  of  the 
articulation  was  established,  when  the  symp- 
toms became  so  aggravated  as  to  demand  the 
speedy  removal  of  the  limb.  The  symptoms 
of  suppuration  within  a  bone  are  exceedingly 
obscure,  nor  is  there  any  certainty  until  the 
abscess  has  burst  and  a  probe  can  be  passed 
into  the  cavity,  particularly  if  the  inflammation 
has  not  been  attended  with  enlargement  of  the 
bone.  The  pain  is  said  to  be  agonizing,  but 
this  is  not  universally  true,  and  we  may  infer 
that  suppuration  has  taken  place  "  by  the 
violent  symptoms  of  active  inflammation  les- 
sening, by  cold  fits  and  shivering  occurring, 
by  a  remission  of  pain  with  an  increased  sense 
of  weight  in  the  part ;  but  all  these  are  fal- 
lacious, and  no  external  marks  of  suppuration 
are  at  first  to  be  observed,  the  disease  affecting 
parts  too  deep  to  be  seen  with  the  eye  or  felt 
with  the  finger/'* 

Suppuration  on  the  surface  of  a  bone  is  of 
very  common  occurrence,  and  so  constantly 
complicated  with  affections  of  the  periosteum, 

*  Wilson  on  the  Bones  and  Joints. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


449 


that  it  is  difficult  to  say  which  structure  is  the 
source  of  the  purulent  secretion ;  the  disease, 
indeed,  is  generally  described  under  the  name 
of  periostitis.  We  are  disposed,  however,  to 
regard  it  as  inflammation  of  the  bone  in  the 
first  instance,  although  the  membrane  comes 
very  soon  to  be  engaged  ;  because  in  many 
cases  the  pain  in  the  commencement  is  not  ag- 
gravated by  external  pressure,  which  it  uni- 
formly is  when  the  periosteum  is  engaged, 
and  also  because  in  very  severe  cases,  such  as 
paronychia  periostei,  a  portion  of  the  bone 
becomes  carious,  and  is  lost  even  from  the 
earliest  period.  It  is  most  frequently  ob- 
served in  connexion  with  some  constitutional 
taint,  such  as  scrofula  or  syphilis,*  but  it  may 
and  very  often  does  appear  purely  as  an  idio- 
pathic  disease.  "  Inflammation  of  the  pe- 
riosteum, unconnected  with  any  known  con- 
stitutional disease,  is  an  affection  with  which 
practical  surgeons  are  well  acquainted.  It  is 
remarkable,  however,  that  a  disease  so  impor- 
tant in  its  consequences  and  of  such  frequent 
occurrence,  should  not  have  been  noticed  in  any 
systematic  work,  nor  have  been  made  the  sub- 
ject of  any  separate  inquiry  ."f 

Whether  we  consider  this  affection  to  belong 
primarily  and  principally  to  the  bone  or  pe- 
riosteum, it  is  certain  that  the  former  structure 
always  is  engaged,  and  shews  the  most  evident 
marks  of  activity  in  the  disease,  although  this, 
perhaps,  may  in  part  be  explained  by  the 
fibrous  texture  of  the  membrane  and  its  defi- 
cient organization.  The  bone  is  always  in- 
flamed. Even  in  the  most  chronic  case  that 
leads  only  to  a  thickened  condition  of  the  pe- 
riosteum, the  bone  is  preternaturally  vascular, 
and  so  soft  that  it  is  often  difficult  in  such 
cases  to  distinguish  the  limits  between  the  sof- 
tened bone  and  the  condensed  periosteum. J 
In  the  severer  forms,  the  bone,  unable  to  sus- 
tain itself  under  the  excitement,  is  always  dead, 
and  must  be  gotten  rid  of  by  ulceration  or 
exfoliation  :  in  these  cases  the  periosteum  is 
detached,  and  a  fluid,  very  generally  thin, 
ichorous,  and  fetid,  is  interposed  between  them. 
Between  these  extremes  there  is  every  possible 
variety,  and,  therefore,  there  will  be  vast  dif- 
ferences in  the  results  of  the  inflammation, 

*  Of  all  the  causes  that  produce  these  affections 
of  the  bones,  an  irregular  or  protracted  use  of  mer- 
cuty  seems  to  be  the  most  efficacious.  Many  sur- 
geons of  the  present  day  doubt  whether  a  suppu- 
rating node  is  a  true  or  genuine  venereal  symptom. 
We  have  learned  from  an  experienced  army  surgeon, 
who  spent  many  years  on  the  western  coast  of  Africa, 
where  the  venereal  disease  is  not  known,  but  where 
mercury  is  profusely  employed  in  the  treatment  of 
liver  complaints  and  other  diseases  incident  to  the 
climate,  that  affections  of  the  bones,  resembling 
those  considered  to  be  venereal,  are  of  exceeding 
frequency.  It  is  a  remark  worthy  of  attention  to 
the  curious  in  such  matters,  that  nodes,  &c.  formed 
no  part  of  the  symptoms  of  syphilis  as  first  observed 
and  described,  and  that  the  first  practitioner  who 
noticed  them  (John  de  Vigo,  1519,)  is  mentioned 
by  Astruc,  (page  158,)  as  an  eminent  promoter  of 
the  mercurial  method  of  cure,  and  as  having  by  that 
means  acquired  great  reputation  and  riches. 

t  See  a  paper  by  Mr.  Crampton,  in  the  Dub. 
Hosp.  Reports,  vol.  i. 

t  Ibid. 
VOL.    I. 


sometimes  in  the  mere  thickening  of  the  pe- 
riosteum, sometimes  in  the  deposition  of  more 
bony  matter,  or  the  apparent  ossification  of  the 
membrane  (exostosis)  ;  occasionally  in  the  ab- 
sorption of  the  bone,  and  most  frequently, 
particularly  in  specific  diseases,  in  that  which 
is  our  more  immediate  object,  the  deposition  of 
purulent  matter. 

A  node  is  a  swelling  situated  over  a  bone, 
hard,  firm,  and  exquisitely  tender  to  the  touch, 
not  round  or  circumscribed  at  its  base,  but 
gradually  subsiding  to  the  level  of  the  adjacent 
parts,  and  not  discoloured  on  the  surface.  It  is 
at  all  times  painful  (except  in  some  scrofulous 
cases),  and  when  arising  from  a  venereal  cause, 
is  subject  to  nocturnal  exacerbations  of  great 
severity.  The  morbid  anatomy  of  the  disease 
is  not  always  the  same  even  when  examined 
at  the  same  period  of  duration,  being  modified 
by  a  number  of  circumstances,  such  as  the 
age  of  the  subject  and  consequent  vascularity 
of  the  bones;  the  structure  of  the  bone  en- 
gaged being  solid  and  firm  or  soft  and  spongy ; 
but  more  particularly  by  the  fact  of  the  disease 
being  idiopathic,  or  produced  by  some  consti- 
tutional affection.  The  scrofulous  diseases  of 
bones  seldom  or  never  exhibit  the  symptom  of 
nodes,  although  attended  by  suppuration,  be- 
cause they  affect  their  substance  rather  than 
their  surfaces  :  idiopathic  nodes,  or  those  pro- 
duced by  injury,  do  not  suppurate  unless  the 
violence  used  is  great ;  on  the  contrary,  these 
are  cases  which  so  frequently  terminate  in 
thickening  of  the  periosteum,  &c.,  and  often, 
when  cut  into,  scarcely  afford  any  perceptible 
discharge.  The  venereal  or  mercurial  node 
offers  the  best  example  of  suppuration.  At  an 
early  period,  if  an  opportunity  occurs  for  exa- 
mination, the  periosteum  round  the  margin  of 
the  effusion  shews  a  more  than  ordinaiy  degree 
of  vascularity ;  immediately  covering  the  tu- 
mour it  is  somewhat  paler,  more  opaque  and 
thickened.  The  bone  underneath  is  denuded 
and  soon  runs  into  caries ;  between  it  and  the 
membrane  the  matter  is  deposited,  thin  in  con- 
sistence, dark-coloured,  and  sanious. 

There  are  other  forms  of  suppuration  on  the 
surface  of  a  bone  of  too  much  interest  and  im- 
portance to  be  omitted,  such  as  those  large  de- 
pots which  occasionally  occur  after  severe  in- 
juries or  operations,  as  the  accompaniments  of 
inflammation  of  the  veins,  or  as  the  sequelae 
of  acute  fevers.  In  general,  the  matter  is  in 
great  quantity  and  of  a  good  and  healthy  cha- 
racter, though  sometimes  it  is  otherwise,  and 
particularly  in  that  form  which  attacks  a  stump 
after  amputation.  We  have  seen  the  entire 
remnant  of  the  bone  up  to  the  next  articulation 
denuded  of  its  periosteum,  while  quantities  of 
green  and  fetid  pus  could  be  pressed  from  the 
very  depths  of  the  wound.  In  these  cases  the 
veins  are  generally  inflamed,  the  divided  ends 
of  the  muscles  pale,  flaccid,  and  sloughy,  and 
the  patient  seldom  or  never  recovers.  Where 
the  deposition  has  taken  place  after  fever,  if 
the  patient  is  young  and  the  constitution  has 
enabled  him  to  combat  the  original  disease,  a 
recovery  very  frequently  takes  place  by  the 
process  of  necrosis. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


450 

Caries  from  a  scrofulous  cause,  generally,  if 
not  always,  commences  in  the  cancellated 
structure  ;  that  from  syphilis  affects  the  firmer 
and  more  external  parts  of  the  bone.  The 
former  attacks  the  ends  of  the  long  bones  and 
the  spongy  and  cuboid  bones  generally ;  the 
latter,  the  centres  of  the  long  bones  and  the  flat 
ones.  Venereal  nodes  principally  affect  the 
bones  which  are  nearest  to  the  surface  of  the 
body,  the  skull,  the  tibia,  or  the  sternum;  it 
being  rare  to  see  the  humerus  or  femur  thus 
diseased,  whilst  they  are  by  no  means  exempt 
from  idiopathic  or  strumous  inflammation. 
But  the  most  remarkable  differences  to  be  ob- 
served between  caries  arising  from  a  specific 
cause,  and  that  which  occurs  idiopathically  or 
from  injury  in  a  constitution  otherwise  good, 
occur  in  the  progress  and  termination  of  the 
disease.  The  process  seems  to  be  analogous 
to  that  of  ulceration  in  the  softer  tissues,  and 
when  recovery  takes  place,  it  is  by  granulation 
and  cicatrization  in  like  manner.  Thus,  if  we 
suppose  an  abscess  to  occur  on  the  surface  of  a 
bone  in  a  healthy  man,  when  it  is  opened  or 
has  burst,  we  find  that  a  scale  or  shell  has  lost 
its  vitality  and  must  be  thrown  off  by  exfo- 
liation, and  soon  exuberant  and  florid  granula- 
tions are  seen  springing  from  below  as  if  to 
force  the  offending  substance  off,  and  the  dis- 
charge from  the  cavity  is  healthy  pus.  On  the 
other  hand,  if  a  venereal  node  is  opened  on  the 
skull,  the  pericranium  is  here  detached,  the 
table  is  carious  and  will  exfoliate,  but  there  is 
(as  long  as  the  taint  remains)  no  effort  at  re- 
paration ;  the  discharge  is  thin,  ichorous,  and 
unhealthy  ;  and  if  we  may  judge  by  the  repre- 
sentations we  see  of  venereal  caries,  (for  in 
modern  times  mercury  is  not  so  unsparingly 
used  and  real  specimens  are  not  numerous,)  the 
disease  would  progress  until  the  skull  was 
fairly  corroded  through.  Again,  the  lymph 
secreted  in  scrofulous  inflammation  is  not 
healthy,  and  there  are  seldom  granulations; 
whilst  the  matter  is  either  of  that  whey-like 
appearance  so  remarkable  in  such  affections,  or 
else  a  foul  and  fetid  sanies.  Every  one  con- 
versant with  surgery  must  know  how  tedious 
and  obstinate  a  scrofulous  caries  is,  and  how 
frequently  it  involves  the  loss  of  limb  or  of 
life. 

The  true  scrofulous  affection  of  the  bones 
occurs  so  frequently  in  this  country  as  to  re- 
quire particular  attention ;  it  constitutes  the 
vast  majority  of  the  diseases  of  the  osseous 
system  that  we  are  called  upon  to  see  and  to 
treat.  It  commences  (as  we  have  said)  in  the 
cellular  or  cancellated  structure.  In  the  first 
instance  there  is  an  increase  of  vascularity, 
which,  though  not  always  apparent  to  the  eye, 
may  easily  be  proved  by  injection.  Next, 
there  is  an  absorption  of  the  natural  contents 
of  the  cancelli,  and  in  their  room  a  substance 
is  deposited  of  a  yellow  or  white  colour  that 
has  been  described  as  resembling  cheese  in 
consistence;  it  is,  however,  most  probably  a 
species  of  that  flocculent  unorganized  lymph, 
such  as  is  seen  coating  the  cysts  of  scrofulous 
abscesses.  The  cancelli  themselves  are  oc- 
casionally removed,  and  masses  or  patches  of 


this  unorganized  material  deposited  in  their 
stead,  hence  the  bone  becomes  lighter,  and  so 
soft  as  to  allow  of  being  cut  with  a  knife.  It 
is  remarkable  that  the  disease  may  have  existed 
up  to  this  period,  when  it  is  probably  incura- 
ble, without  much  pain  and  without  external 
swelling  to  attract  attention  to  the  mischief 
underneath.  In  the  Museum  of  the  School  of 
Anatomy,  &c.  of  Park-street,  Dublin,  there  is 
a  preparation  to  illustrate  necrosis  of  the  centre 
of  the  shaft  of  the  thigh-bone,  for  which  the 
limb  was  amputated.  The  patient  during  life 
never  complained  of  the  knee,  neither  was 
there  the  smallest  enlargement  of  the  articula- 
tion; yet  after  removal  the  condyles  of  the 
femur  internally  were  completely  softened,  the 
external  shell  of  solid  bone  being  reduced  in 
thickness  nearly  to  that  of  parchment,  the  can- 
cellated structure  completely  removed,  and  its 
place  occupied  by  this  cheesy  substance. 

This  condition  of  the  bones  is  considered  by 
Mr.  Lloyd*  as  constituting  the  first  stage  of 
scrofulous  disease,  and  he  justly  remarks  that 
it  is  quite  uncertain  how  long  they  may  con- 
tinue in  this  state  without  further  mischief 
taking  place.  The  next  step  is  the  erosion  or 
absorption  of  the  cartilages,  if  the  affection  is 
situated  in  the  head  of  a  bone,  (see  JOINT,)  or 
otherwise  near  an  articulation,  and  probably 
about  the  same  period  the  external  soft  parts 
sympathise,  and  lymph  is  extensively  deposited 
around  the  deep  fibrous  tissues  in  the  neigh- 
bourhood. This  lymph  is  afterwards  to  be- 
come the  seat  of  abscesses,  which  always 
communicate  with  the  diseased  bone,  and  very 
generally  with  the  cavity  of  the  adjacent  joint. 
The  limb  or  part  is  now  swollen  :  the  tume- 
faction is  round  and  well  defined,  tolerably 
firm  in  consistence,  and  elastic  to  the  touch ; 
the  colour  of  the  skin  is  of  a  more  than  ordi- 
nary paleness,  and  its  surface  is  marked  by 
the  meandering  lines  of  numerous  small  blue 
veins.  The  growth  of  the  tumour  seems  to  be 
limited,  for  having  reached  a  given  size  it 
becomes  stationary  and  never  increases,  al- 
though the  disease  may  appear  at  times  even 
more  fully  developed.  Subsequently  the  pain 
is  very  variable ;  that  attending  on  scrofulous 
diseases  being  generally  described  as  dull  and 
heavy  rather  than  acute,  but  this  idea  must  be 
received  with  some  limitation,  for  occasionally 
the  very  reverse  is  the  truth.  We  have  seen 
some  patients  the  victims  of  most  intense  irri- 
tation and  suffering  throughout  every  stage  of 
carious  ulceration  ;  and  even  when  it  is  other- 
wise, they  are  always  liable  to  severe  exacer- 
bations on  any  injudicious  attempt  at  motion, 
any  improper  diet  or  other  irregularity.  In 
all  cases  there  seems  to  be  a  considerable  ag- 
gravation of  symptoms,  both  local  and  consti- 
tutional, about  the  period  when  suppuration  is 
established,  and  whilst  the  matter  is  progress- 
ing towards  the  surface. 

It  may  be  a  long  time  before  the  tumour 
gives  indications  of  being  about  to  burst  exter- 
nally, partly  perhaps  from  the  imperfect  organi- 
zation of  the  lymph  by  which  the  matter  is 

*  See  Lloyd  on  Scrofula. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


451 


secreted,  and  partly  because  it  seldom  takes 
the  shortest  route  to  the  surface,  but  proceeds 
by  devious  and  intricate  windings.  At  length 
the  tumour,  at  one  limited  and  almost  circum- 
scribed spot,  becomes  soft,  then  assumes  a  dark 
red  or  purple  colour,  finally  a  small  slough 
forms  on  the  surface  and  it  bursts,  giving  exit 
in  general  to  a  greater  quantity  of  matter  than 
the  size  of  the  abscess  would  have  led  us  to 
anticipate.  The  abscess  does  not  collapse,  and 
although  the  discharge  may  continue  in  pro- 
fusion for  months,  the  size  of  the  tumefaction 
is  never  proportionally  diminished.  After  it 
has  burst,  a  small  papilla  of  very  red  granu- 
lation (a  most  unfailing  symptom  of  the  exis- 
tence of  a  diseased  bone  underneath)  is  pushed 
out  through  the  aperture.  From  the  centre  of 
this  a  small  drop  of  matter  can  generally  be 
pressed,  and  through  it  the  discharge  flows; 
never  for  obvious  reasons  profusely  at  a  time, 
but  still  so  constantly  as  to  soil  the  dressings 
and  the  bed-clothes  extensively  in  a  single 
night.  When  a  probe  is  passed  down  to  the 
bottom  of  this  ulcer,  which  it  is  not  easy  al- 
ways to  accomplish,  the  bone  is  felt  completely 
denuded,  soft  and  rotten,  and  the  instrument 
sinks  into  it  with  very  little  resistance.  Most 
frequently  the  earthy  material  of  the  bone  is 
removed  by  the  absorbents  ;  sometimes  a  small 
portion  of  it  thus  detached  is  washed  off  by 
the  discharge,  and  is  occasionally  found  block- 
ing up  the  little  orifice,  occasioning  a  good 
deal  of  irritation  and  pain,  and  almost  always 
an  access  of  fever.  Sometimes  the  remains  of 
the  bone  come  away  in  a  larger  mass,  quite 
dead,  light,  and  porous,  and,  when  dried,  per- 
fectly friable. 

Previous  to  the  formation  of  the  matter, 
however,  the  pathological  state  of  the  bone  has 
undergone  a  remarkable  change.  Hitherto  we 
have  seen  that  an  increase  of  vascularity  oc- 
curred at  an  early  period,  and  preceded  the 
deposition  of  the  soft  and  cheesy  substance; 
but  in  proportion  as  this  deposit  is  increased  in 
quantity,  the  vascularity  decreases,  and  with  it 
the  vitality  of  the  bone.  "  If  a  scrofulous 
bone  be  injected  at  an  early  period,"  says  Mr. 
Lloyd,  "  or  before  the  whole  of  its  cancellous 
structure  is  altered,  the  injection  very  freely 
enters  its  vessels ;  but  if  it  be  injected  at  a 
more  advanced  period,  there  evidently  appear 
to  be  fewer  vessels,  though  it  is  very  probable 
that  a  fine  injection  may  be  forced  into  vessels 
which  had  previously  ceased  to  carry  blood." 
In  the  correctness  of  this  observation  Sir  B. 
Brodie  coincides,  as  well  as  in  the  opinion 
"  that  this  diminution  of  the  number  of  ves- 
sels, and,  consequently,  of  the  supply  of  blood, 
is  probably  the  proximate  cause  of  those  exfo- 
liations which  sometimes  occur,  where  the 
disease  has  existed  for  a  considerable  length  of 
time,  especially  in  the  smaller  bones."* 

Although  carious  ulceration,  or,  as  it  would 
be  more  correctly  termed,  absorption  of  bone, 
is  so  frequently  attended  by  the  formation  of 
matter  and  abscess,  yet  such  is  by  no  means  a 

*  See  Lloyd  on  Scrofula,  p.  123,  and  Brodie  on 
the  Joints,  last  edition,  p.  195. 


necessary  consequence — at  least,  we  have  ex- 
amples of  the  removal  of  large  portions  of 
bones  without  any  such  unfortunate  accompa- 
niment. These  principally  appear  under  two 
distinct  forms  :  one,  where  such  absorption  is 
the  result  of  inflammatory  action  within  the 
bone  itself,  the  most  familiar  illustration  of 
which  is  to  be  found  in  the  caries  of  the  spine 
attending  on  some  cases  of  angular  curvature  : 
the  other,  where  the  absorption  has  been  occa- 
sioned by  the  pressure  of  an  aneurism,  an 
abscess,  or  other  tumour  in  the  immediate 
neighbourhood. 

Mr.  Pott,  and  others  who  have  described 
this  caries  of  the  spine,  mention  that,  at  first, 
the  bodies  of  the  vertebrae  seem  to  spread  so 
as  absolutely  to  become  larger  than  in  a  state 
of  health;  that  the  ligaments  are  loose  and 
detached,  and  the  intervertebral  cartilages  sepa- 
rated from  the  bone.  The  first  part  of  this 
description  is  certainly  not  correct,  for  in  all 
the  subjects  we  have  had  opportunities  of  ex- 
amining, nothing  like  an  enlargement  or  swelling 
of  the  bone  appeared.  It  must  be  recollected 
that  dissections  of  this  disease  at  an  early 
period  are  rarely  met  with — never  unless  the 
patient  had  been  accidentally  seized  by  some 
mortal  affection  soon  after  the  spine  had  been 
attacked.  It  may,  therefore,  be  supposed  that 
these  early  descriptions  were  taken  from  ana- 
logy with  what  other  bones  suffer  in  scrofulous 
disease,  and  it  is  well  known  that,  until  a  com- 
paratively recent  period,  it  was  a  universally 
received  opinion  that  the  heads  of  bones  be- 
came actually  enlarged  under  similar  circum- 
stances. 

Sir  B.  Brodie,  who  has  given  the  clearest  as 
well  as  the  most  succinct  description  of  caries 
of  the  spine  we  have  met  with,  considers  that 
its  pathological  history  may  be  arranged  under 
three  heads. 

1.  "  It  has  its  origin  in  that  peculiar  sof- 
tened and  otherwise  altered  condition  of  the 
bodies  of  the  vertebrae,  which  seems  to  be 
connected  with  what  is  called  a  scrofulous  state 
of  constitution.  In  these  cases  ulceration  may 
begin  on  any  part  of  the  surface,  or  even  in 
the  centre  of  the  bone,  but  in  general  the  first 
effects  of  it  are  perceptible  where  the  interver- 
tebral cartilage  is  connected  with  it  and  in  the 
intervertebral  cartilage  itself."* 

As  this  is  an  instance  of  scrofulous  caries, 
such  as  has  been  already  noticed,  it  should 
perhaps  have  come  more  legitimately  under 
consideration  in  that  part  of  our  article.  We 
prefer,  however,  to  take  a  distinct  and  separate 
view  of  caries  of  the  spine,  because  the  locality 
invests  the  disease  with  some  peculiarities. 
For  instance,  this  scrofulous  caries  is  almost 
invariably  attended  by  abscess,  and  we  find 
these  collections  to  be  much  larger  in  quantity 
of  contents,  and,  if  possible,  more  sluggish  in 
approach  to  the  surface  than  when  situated 
elsewhere.  Their  existence,  therefore,  may  not 
only  not  be  suspected,  but  the  symptoms  occa- 
sioned by  them  during  life  may  be  attributed 
to  a  totally  different  cause.  They  are  least 

*  Brodie  on  the  Joints,  p.  243. 
2  G   2 


452 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


frequently  met  with  in  the  neck,  but  when  so 
situated  it  is  easy  to  conceive  how  they  may 
occasion  dysphagia  or  difficult  respiration. 
We  have  seen  a  case  where  such  an  abscess 
occasioned  symptoms  resembling  those  of  com- 
pression of  the  brain,  and  we  have  the  notes  of 
one  in  which  death  was  produced  in  a  very 
sudden  and  unexpected  manner,  the  matter 
having  burst  into  the  sheath  of  the  spinal 
marrow.  They  may  also  occur  in  connexion 
with  disease  of  the  dorsal  vertebrae,  and  within 
the  chest  give  rise  to  symptoms  resembling  the 
different  forms  of  deranged  respiration — tho- 
racic aneurism — and,  under  peculiar  circum- 
stances, even  of  empyema.  Such  difficulties 
are  now  not  so  likely  to  occur,  as  we  have 
auscultation  to  assist  the  diagnosis;  but  we 
recollect  to  have  seen  more  than  one  case 
treated  as  a  pulmonary  affection,  the  real  nature 
of  which  was  caries  of  the  dorsal  vertebrae, 
complicated  with  abscess  pressing  forward 
within  the  posterior  mediastinum.  Abscess  in 
the  loins  connected  with  diseased  vertebrae  is 
too  familiar  an  occurrence  to  require  any 
lengthened  details. 

As  far  as  our  own  observation  can  guide  us, 
we  believe  the  appearance  of  abscess  as  an 
accompaniment  of  spinal  disease  to  be  almost 
always  a  fatal  symptom ;  and  when,  in  the 
course  of  a  wasting  and  protracted  discharge, 
spiculae  of  carious  bone,  or  portions  of  a  sub- 
stance resembling  ivory  or  enamel  are  seen  to 
come  away,  the  aspect  of  the  case  is  still 
farther  formidable — very  few,  if  any,  ever 
recover  under  such  circumstances. 

2.  "  In  other  cases  the  vertebrae  retain  their 
natural  texture  and  hardness,  and  the  first 
indication  of  the  disease  is  ulceration  of  one  or 
more  of  the  intervertebral  cartilages,  and  of 
the  surfaces  of  bone  with  which  they  are  con- 
nected."* 

"  There  is  still  another  order  of  cases,  but 
these  are  of  more  rare  occurrence,  in  which 
the  bodies  of  the  vertebrae  are  affected  with 
chronic  inflammation,  of  which  ulceration  of 
the  intervertebral  cartilages  is  the  consequence." 
We  shall  now  proceed  to  detail  the  results 
of  our  own  observations^  in  order  to  see  how 
far  they  coincide  with  those  of  the  learned  and 
accurate  surgeon  already  quoted. 

In  two  instances  we  have,  in  the  dissecting 
room,  seen  the  intervertebral  substance  eroded 
at  the  anterior  edge,  the  bodies  of  the  adjacent 
bones  remaining  unaltered  in  shape  or  consis- 
tence, and  to  every  appearance  in  a  perfectly 
healthy  condition.  These  were,  at  the  time, 
regarded  as  specimens  of  the  very  earliest  and 
incipient  stage  of  the  disease,  and  although  no 
clue  could  be  obtained  as  to  the  history  of  the 
cases,  it  is  worthy  of  remark  that  not  a  trace  of 
scrofulous  disease  could  be  discovered  in  any 
other  parts  of  the  bodies. 

In  general,  however,  it  is  otherwise.  The 
body  of  the  bone  seems  to  be  seized  with 
scrofulous  inflammation,  and  the  peculiar  ef- 
fects of  this  morbid  action  are  produced  within 
it.  It  becomes  softer  in  consistence,  in  conse- 

*  Brodie,  loc.  citat. 


quence  of  the  absorption  of  its  osseous  parti- 
cles, and  a  deposition  of  the  cheesy  lymph  in 
its  stead.  At  this  time,  although  so  soft  as  to 
admit  of  being  cut  with  a  knife,  the  bone  ap- 
pears unaltered  as  to  size  or  shape,  but  its 
absorbents  begin  to  act  upon  the  ligaments  and 
intervertebral  cartilages,  and  hence  is  it  that 
the  separation  and  ulceration  of  these  are 
amongst  the  earliest  appearances.  In  many 
instances  the  connexion  between  the  cartilage 
and  bone  is  so  much  impaired,  that  if  we 
wanted  to  separate  them  with  a  knife,  the  former 
would  come  off  in  one  entire  flake.  The 
edges  then  begin  to  be  eroded  and  ulcerated, 
as  if  gnawed  by  a  mouse ;  and  at  this  period 
also  the  ligaments  are  often  found  thickened 
and  softened,  and  matted  up  together  into  a 
confused  and  indistinct  mass.  The  body  of 
the  bone  then  becomes  carious,  and  the  ulce- 
ration commences  at  the  anterior  part  of  it : 
very  rarely  is  the  posterior  layer  of  firm  bone, 
that  forms  the  front  of  the  canal  for  the  spinal 
marrow,  affected;  and  never  does  the  caries 
spread  to  the  processes.  Up  to  this  period  it 
may  be,  and  often  is,  a  specimen  of  purely  dry 
caries,  being  unattended  by  the  formation  of  a 
single  drop  of  purulent  matter. 

As  the  disease  proceeds,  and  the  bodies  of 
one  or  more  vertebrae  are  removed,  those  which 
remain  approximate  more  or  less  above  and 
below:  the  spinous  processes  project,  and  a 
bending  of  the  body  forward  is  produced. 
The  character  of  this  curve  is  influenced  by 
the  extent  of  the  destruction  that  has  been 
accomplished  within ;  it  is  sharper  and  more 
angular  when  the  body  of  one  vertebra  only  has 
been  removed;  it  is  more  sweeping  and  gradual 
when  three  or  four  have  suffered.  Never,  we 
believe,  is  the  angle  so  sharp  as  to  permit  the 
denuded  surfaces  of  the  vertebrae  above  and 
below  to  come  into  actual  contact,  the  sound 
condition  of  the  bony  parietes  of  the  spinal 
sheath  effectually  preventing  this ;  and  hence, 
when  recovery  takes  place,  it  is  not  by  the 
adhesion  of  these  surfaces,  but  by  the  forma- 
tion of  a  quantity  of  new  bone  which  fills  up 
the  vacant  space,  producing  a  perfect  example 
of  true  anchylosis. 

The  developement  of  such  a  curative  pro- 
cess as  this  is  scarcely  to  be  expected  in  a 
scrofulous  system,  yet  is  it  satisfactory  to  know 
that  even  under  such  circumstances  the  case  is 
not  utterly  hopeless.  We  have  seen  repeated 
instances  of  angular  curvature  without  the 
occurrence  of  abscess,  in  patients  apparently 
deeply  tainted  with  scrofula,  one  of  which  is 
so  very  remarkable  as  to  deserve  particular 
notice,  because  it  illustrates  a  mode  of  union 
that  frequectly  occurs  in  scrofulous  cases,  and 
because  the  preparation  is  in  existence  to  de- 
monstrate the  fact.  In  July,  1830,  a  wretched 
young  girl  was  brought  into  the  Meath  hospital 
with  a  very  acute  angular  curvature  of  the 
dorsal  vertebrae.  Almost  every  joint  in  her 
body  was  diseased,  and  the  knees  so  extensively 
that  the  eroded  condyles  of  the  thigh-bones  were 
exposed,  from  the  surface  of  one  of  which  the 
mud  of  the  street  was  wiped  away  after 
her  admission.  It  need  scarcely  be  added 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


that  her  sufferings  were  not  of  long  duration, 
and  an  opportunity  was  speedily  afforded  for 
examining  the  pathological  condition  of  the 
back.  It  appeared  that  three  of  the  vertebrae 
had  been  engaged,  the  spongy  portion  of  one 
of  which  had  been  completely  removed.  There 
was  nothing  like  a  reproduction  of  osseous 
material,  although  the  caries  had  long  ceased, 
and  the  spine  was  sufficiently  strong  for  every 
ordinary  purpose  of  support ;  but  the  space 
that  had  been  left  by  the  absorption  of  the 
bone  was  filled  up  by  a  ligamento-cartilaginous 
substance,  which,  attached  like  a  new  and 
adventitious  ligament  to  the  vertebrae  above 
and  below,  held  them  with  a  sufficient  tight- 
ness to  prevent  the  smallest  motion,  and  gave 
to  the  entire  column  a  tolerable  degree  of  firm- 
ness. We  have  also  seen  examples  of  true 
bony  anchylosis  in  patients  apparently  scrofu- 
lous, but  it  seems  to  occur  generally  in  males 
rather  than  in  females,  and  more  particularly 
in  patients  about  or  approaching  to  the  age  of 
puberty,  a  period  at  which  it  is  generally  sup- 
posed some  important  change  takes  place  in 
the  constitution  of  scrofulous  subjects.  Where 
there  is  no  such  taint,  or  where,  as  Sir  B. 
Brodie  expresses  it,  the  bones  retain  their  na- 
tural texture  and  hardness,  it  may  be  easily 
conceived  that  a  cure  is  effected  in  less  time 
and  with  less  difficulty. 

There  is  another  specimen  of  caries  or  ulce- 
ration  of  bone  without  the  formation  of  matter, 
occasionally  observed  in  the  neck  of  the  thigh- 
bone of  very  old  persons,  the  symptoms  of 
which  have  particular  relation  to  the  hip-joint; 
we  shall  therefore  postpone  our  remarks  on  it 
until  we  come  to  discuss  the  pathology  of 
joints. 

Necrosis. — There  are  few  subjects  more  in- 
teresting either  to  the  pathological  inquirer  or 
to  the  practical  surgeon  than  the  death  of  a 
portion  of  the  osseous  system,  and  the  circum- 
stances connected  with  this  event.  Neither  is 
there  any  one  with  respect  to  which  the  ideas 
of  medical  men  generally  are  less  definitively 
settled.  Thus  also  some  confusion  has  crept 
into  our  nomenclature,  and  necrosis  and  ex- 
foliation have  been  often  indifferently  used,  as 
if  they  applied  to  one  and  the  same  diseased 
action ;  or,  perhaps,  to  speak  more  correctly, 
the  term  necrosis  has  been  made  to  extend  to 
every  case  in  which  a  bone  or  a  portion  of  a 
bone  is  deprived  of  vitality,  no  matter  how 
the  dead  material  is  to  be  removed  or  replaced. 
According  to  the  etymology  of  the  term  such 
is  in  fact  its  true  meaning;  nevertheless,  we 
are  hardy  enough  to  dissent  from  this  applica- 
tion of  the  word,  and  to  confine  its  use  lo  one 
form  of  the  death  of  a  bone,  exfoliation  more 
properly  belonging  to  another.  And  we  do  so 
the  more  readily  because  not  only  do  these  two 
affections  present  different  pathological  pheno- 
mena, but  there  are  such  practical  discrepancies 
between  them  that  it  is  essential  to  every  sur- 
geon to  have  a  distinct  and  separate  notion  of 
each. 

Exfoliation,  then,  expresses  the  death  of  a 
portion  of  bone  which  is  either  never  replaced, 
or  replaced  by  a  process  which  is  set  up  after 


its  death,  and  is  analogous  to  mortification  in 
the  soft  parts,  where  the  slough  is  thrown  off, 
and  the  consequent  ulcer  subsequently  heals  by 
granulation  and  cicatrization. 

Necrosis  is  the  death  of  a  bone  or  part  of  a 
bone  accompanied  by  a  process  of  regeneration 
established  at  a  time  coeval  or  nearly  coeval 
with  the  inflammation  or  accident  that  deprives 
it  of  vitality.  In  this  point  of  view  the  disease 
is  singular,  there  being  nothing  like  or  ana- 
logous to  it  in  any  affection  of  the  soft  parts. 

Necrosis  is  rarely  a  disease  of  early  and 
never  of  advanced  life,  being,  except  in  cases 
where  it  attacks  the  lower  jaw,  almost  exclu- 
sively confined  to  the  period  between  the  ages 
of  ten  and  twenty-two :  exfoliation  may  occur 
at  any  time,  but  is  more  likely  to  appear  in  the 
adult  or  the  aged. 

Necrosis,  although  it  may  succeed  to  acci- 
dent, as  in  this  manner  compound  fractures  and 
other  injuries  are  not  infrequently  repaired,  yet 
is  it  more  generally  an  idiopathic  disease,  or 
may  be  the  sequela  of  continued  fever;  whilst 
exfoliation  in  the  great  majority  of  instances  is 
the  consequence  of  injury. 

According  to  the  acceptation  in  which  we 
employ  the  term,  it  is  extremely  questionable 
whether  necrosis  is  ever  a  disease  of  the  flat 
bones;  at  least,  except  in  the  instance  of  the 
lower  jaw,  we  have  never  met  with  an  example 
of  the  death  of  one  of  these  structures  accom- 
panied or  even  followed  by  a  regenerative  pro- 
cess. 

As  necrosis,  then,  presents  a  solitary  exam- 
ple of  the  efforts  of  nature  in  counteracting,  or 
rather  in  providing  against  the  ravages  of  dis- 
ease, the  process  by  which  it  is  accomplished 
becomes  an  exceedingly  interesting  subject  of 
inquiry.  Different  opinions  are  entertained 
upon  this  subject.  It  seems  to  be  agreed 
upon  all  sides  that  the  commencement  of  the 
disease  is  marked  by  inflammation  of  the  bone: 
at  this  period  it  is  red,  vascular,  and  receives 
the  tinge  of  coloured  injections.  How  this  in- 
flammation may  be  caused  or  why  it  is  followed 
by  the  formation  of  new  bone,  are  points  not  so 
easily  determined.  Troja  introduced  a  sharp 
instrument  through  a  bone,  by  which  he  con- 
trived to  destroy  the  internal  periosteum  and 
marrow,  and  thus  produced  a  number  of  cases 
of  necrosis,  which  presented  the  same  sym- 
ptoms and  ran  the  same  course  as  if  they  had 
been  examples  of  idiopathic  disease.  Hence  it 
came  to  be  believed  that  the  death  of  the  inter- 
nal periosteum  was  a  necessary  prelude  to 
necrosis,  until  it  was  observed  that  the  parts 
surrounding  a  bone  had  assumed  those  actions 
which  end  in  the  formation  of  a  new  one  before 
the  absolute  destruction  of  any  part  of  the  old 
one  whatsoever;  and  therefore  that,  although 
the  injury  inflicted  on  the  internal  periosteum 
might  cause  necrosis,  yet  it  was  only  one  cause, 
and  acted  by  creating  inflammation  within  the 
substance  of  the  bone.  Thus  we  are  obliged  to 
return  to  the  point  from  which  we  set  out :  we 
know  that  inflammation  is  established  within 
the  bone,  and,  coeval  with  this  or  nearly  so, 
that  nature  commences  the  process  of  repro- 
duction ;  but  why  this  latter  is  confined  to  a 


454 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


limited  period  of  our  existence,  or  why  even 
amongst  young  persons  it  may  occur  in  one 
individual  and  not  in  another,  form  questions 
to  which,  in  the  present  state  of  our  knowledge, 
we  can  give  no  answer.  We  are  not  even 
agreed  on  the  different  steps  of  the  process  or 
on  the  structure  principally  engaged. 

It  has  been  observed  that  the  portion  of  the 
bone  which  is  to  die,  and  for  some  space  above 
and  below  it,  is  surrounded  by  a  dense  thick- 
ened mass,  of  rather  a  gelatinous  character ; 
that  this  mass,  after  a  very  short  time,  becomes 
opaque  in  detached  spots,  and  that  depositions 
of  osseous  material  are  found  within  it,  so  that 
a  case  of  bone  may  be  constructed  around  the 
original  one  before  it  actually  dies,  and  thus 
the  limb  never  be  entirely  deprived  of  support.* 
As  soon  as  the  dead  bone  separates  from  this 
surrounding  mass,  the  internal  surface  of  this 
new  material  becomes,  under  some  circum- 
stances, covered  with  a  layer  of  lymph,  and 
under  others  with  regular  ossific  granulations, 
which  gradually  increase  until  a  new  bone  is 
formed,  nearly  as  serviceable,  though  not  so 
symmetrical  or  so  beautiful  as  the  old  one.  It 
next  becomes  a  question,  what  is  this  gelatinous 
mass,  and  whence  is  it  derived  ?  It  has  been 
supposed  that  it  was  the  periosteum  of  the  old 
bone  swelled  and  thickened,  and  at  the  same 
time  softened  in  consistence ;  and  this  opinion 
has  been  strengthened  by  Dr.  Macartney ,f  the 
present  Professor  of  Anatomy  in  the  University 
of  Dublin,  who  stated  that  he  had  opportunities 
of  watching  the  progress  of  the  disease  from  its 
earliest  periods  upwards.  According  to  this 
gentleman,  "  the  first  and  most  important  cir- 
cumstance is  the  change  that  takes  place  in  the 
organization  of  the  periosteum  :  this  membrane 
acquires  the  highest  degree  of  vascularity,  be- 
comes considerably  thickened,  soft,  spongy,  and 
loosely  adherent  to  the  bone ;  the  cellular  sub- 
stance, also,  which  is  immediately  connected 
with  the  periosteum,  suffers  a  similar  alteration : 
it  puts  on  the  appearance  of  being  inflamed,  its 
vessels  enlarge,  lymph  is  shed  into  its  inter- 
stices, and  it  becomes  consolidated  with  the 
periosteum."  Next,  "  the  newly  organized  pe- 
riosteum, which,  for  the  sake  of  distinction,  one 
might  call  the  vascular  sheath  or  investment, 
separates  entirely  from  the  bone,  after  which  it 
begins  to  remove  the  latter  by  absorption,  and 
during  the  time  that  this  process  is  carrying  on, 
the  surface  of  the  vascular  investment,  which  is 
applied  to  the  bone,  becomes  covered  with 
little  eminences,  exactly  similar  to  the  granula- 
tions of  a  common  ulcer."  To  this  doctrine 
Mr.  Russell,  of  Edinburgh,  strongly  objected. 
He  stated  that  if  the  osseous  matter  was  depo- 
sited between  the  layers  of  periosteum,  both  the 
external  and  internal  surfaces  of  the  new  de- 
posit ought  to  be  perfectly  smooth,  whereas  the 
contrary  is  observed — they  are  rough,  irregular, 
and  one  of  them  is  covered  with  granulations. 
He  instanced  cases  of  fracture  in  which,  one 
fragment  overlapping  the  other,  and  being  thus 

*  See  Russell  on  Necrosis, 
t  See  Crowther  on  White  Swelling.      Edition 
1808,  p.  183. 


permanently  entangled,  the  periosteum  between 
the  two  can  have  no  share  in  the  reproduction, 
and  yet  the  whole  is  united  by  a  cylindrical 
shell  of  bone,  on  the  principle  of  reproduction 
in  necrosis.  It  is  also  known  that  compound 
fractures,  where  the  fragments  have  been  exten- 
sively stripped  of  periosteum,  have  united  in 
the  same  way,  and  the  regeneration  of  bone,  in 
these  instances,  could  not  be  attributed  to  peri- 
osteum, inasmuch  as  that  had  been  destroyed. 
It  must  be  owned  that  this  is  a  very  unusual 
occurrence  in  compound  fractures,  but  one  sin- 
gle example  will  be  sufficient  to  prove  that  the 
reproduction  can  take  place  independently  of 
the  periosteum.  And  again,  in  cases  where 
disease  has  caused  the  sloughing  and  destruc- 
tion of  the  periosteum,  as  for  instance  in  deeply 
seated  paronychia,  still  reproduction  is  some- 
times accomplished  by  a  process  resembling 
necrosis.  These  arguments  seem  to  be  very 
decisive  in  overturning  the  doctrine  of  the  sur- 
rounding shell  being  formed  by  the  periosteum, 
and  accordingly  Russell  supposed  that  a  depo- 
sition takes  place  from  all  the  surrounding 
structures  ;  that  it  is  at  first  gelatinous ;  that  it 
soon  assumes  the  appearance  of  cartilage ;  and 
that  at  the  end  of  twenty-four  days  bony  specks 
may  be  discovered  within  it.  The  external 
surface  of  this  deposit  is  rough,  and  attached  to 
the  surrounding  parts :  its  thickness  is  quite 
unequal,  being  greater  in  proportion  to  the  du- 
ration of  the  disease,  and  always  more  so  than 
the  bone  it  is  destined  to  replace.  The  internal 
surface,  or  that  next  the  old  bone,  is  more 
smooth,  and  covered  either  with  lymph  or  gra- 
nulations. Boyer,  Meckel,  Weidmann,  and 
other  continental  surgeons,  attribute  the  process 
nearly  altogether  to  the  periosteum,  and  there- 
fore their  opinions  need  not  be  particularly  dis- 
cussed ;  but  it  is  proper  to  mention  that  all  the 
very  accurate  descriptions  we  read,  of  the  pro- 
gress from  gelatine  to  cartilage  and  from  carti- 
lage to  bone,  must  be  received  with  the  utmost 
caution.  It  is  by  no  means  usual  to  meet  with 
cases  exemplifying  these  descriptions;  and 
amongst  a  considerable  number  of  dissections 
of  necrosis,  it  will  perhaps  be  difficult  to  find 
one  in  which  the  existence  of  cartilage  can  be 
separately  and  distinctly  shown. 

Such  is  an  outline  of  the  chief  opinions  en- 
tertained on  this  interesting  subject,  and  it  is 
probable  that,  to  a  certain  extent,  they  are  all 
correct.  When  the  periosteum  has  not  been 
removed  or  spoiled,  there  can  be  no  doubt  that 
it  is  deeply  and  even  principally  engaged  in  the 
process  of  reproduction.  In  the  museum  at 
Park-street,  the  specimens  exhibiting  the  earliest 
period  of  the  disease  show  the  periosteum  as 
slightly  thickened,  smooth  on  its  internal,  but 
more  rough  and  flocculent  on  its  external  sur- 
face, detached  from  the  bone,  the  surface  of 
which  is  smooth,  and  scarcely  appears  changed 
from  its  natural  and  healthy  condition.  At  a 
more  advanced  period,  the  periosteum  is  still 
thicker,  but  is  not  softened ;  on  the  contrary, 
it  has  nearly  the  firmness  of  ligament,  and 
there  are  small  osseous  depositions  within  it ; 
the  bone  then  being  rough  and  uneven  on  its 
surface  and  evidently  having  lost  its  vitality. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


455 


But  although  we  concede  to  the  periosteum  the 
principal  office  in  the  process  of  reproduction, 
we  can  also  conceive  that  the  adjacent  tissues 
are  also  more  or  less  engaged,  for  the  thicken- 
ing of  parts  is  found  to  extend  on  the  outside 
of  this  membrane,  and  Dr.  Macartney  himself 
speaks  of  the  cellular  tissue  external  to  the 
periosteum  becoming  altered  and  condensed. 
Now,  supposing  the  periosteum  to  be  destroyed, 
these  structures  may  be  capable  of  supplying 
its  place  and  producing  the  secretion  of  gelati- 
nous substance,  which  is  afterwards  to  become 
bone,  just  as  we  see  that  if  the  periosteum  is 
torn  off"  a  bone,  the  adjacent  tissues  laid  down 
upon  it  may  prevent  exfoliation,  and  answer 
every  purpose  of  nutrition  and  preservation 
that  the  original  membrane  did.  From  what- 
ever source  derived,  this  deposition  begins 
while  yet  the  original  bone  is  in  a  state  of  in- 
flammation, and  the  part  that  is  to  die  still  un- 
detached.  If  tendons  or  muscles  are  inserted 
into  this  part  of  the  bone,  they,  being  living  and 
organized  substances,  separate  from  that  which 
is  dead  :  but  the  previous  deposition  has  ex- 
tended about  them,  and  fastened  them  in  their 
situations,  and  hence  not  only  is  the  limb  capa- 
ble of  support  during  the  progress  of  necrosis, 
but  unless  in  exceedingly  rapid,  acute,  and  un- 
favourable cases,  its  motions  may  not  be  very 
materially  impaired. 

Soon  after  the  investing  shell  has  been  form- 
ed, the  dead  portion  of  the  bone  separates  from 
its  attachments,  and  lies  within  its  osseous 
case.  It  is  now  termed  the  sequestrum,  and 
presents  some  remarkable  and  peculiar  charac- 
ters that  distinguish  it  from  diseased  bone 
otherwise  circumstanced.  Its  extremities  are 
always  jagged,  pointed,  and  uneven  :  its  mar- 
row and  internal  periosteum  have  disappeared  : 
its  length  and  its  diameter  are  always  much 
less  than  ought  to  be  anticipated  from  consi- 
dering the  size  of  the  bone  that  has  died ;  and 
its  surface  is  uneven  and  marked  with  slight 
depressions,  as  if  part  of  its  substance  had 
been  taken  up  by  the  absorbents.  This  ap- 
pearance is  more  distinctly  observable,  and  the 
sequestrum  is  always  smaller  where  the  surface 
of  the  new  shell  is  covered  with  granulation, 
than  when  it  is  only  smeared  over  with  lymph. 
And  here,  as  in  other  cases,  it  may  be  observed 
that  the  existence  of  granulation  or  of  lymph 
on  the  new  bone  seems  greatly  to  depend  on 
the  free  admission  of  air  to  the  cavity.  Where 
the  bone  is  deep-seated,  as  in  the  thigh,  and 
there  are  but  a  few  sinuous  apertures  that  can 
scarcely  render  the  cavity  analogous  to  an  open 
sore,  the  surface  is  covered  by  a  layer  of  lymph ; 
but  where  it  is  more  superficial,  as  when  the 
shaft  of  the  tibia  has  come  away  and  left  the 
new  osseous  deposit  totally  uncovered,  its  entire 
surface  is  seen  studded  over  with  healthy  gra- 
nulations, which,  on  passing  the  handle  of  a 
scalpel  over  them,  are  found  to  be  gritty,  and 
give  sensible  indications  of  containing  bony 
matter. 

From  the  first  formation  of  the  new  deposit, 
small  holes  or  perforations  exist  in  it,  the  edges 
of  which  are  bevelled  down  and  thin,  and  not- 
withstanding that  the  new  bone  may  and 


usually  does  become  extremely  thick  and 
spongy,  these  apertures  still  remain  thin  :  it  is 
through  them  the  matter  makes  its  way  to  the 
surface  and  forms  the  fistulous  ulcers  that 
attend  on  this  disease,  and  are  to  be  described 
hereafter.  These  apertures  remain  as  long  as 
there  is  a  single  spicula  of  sequestrum  within  to 
keep  up  irritation  and  protract  the  suppuration. 
After  the  sequestrum  has  completely  disap- 
peared, the  growth  of  osseous  material  st.ll 
continues  internally  until  the  new  shaft  appears 
one  solid  mass  devoid  of  any  cancellated  or 
medullary  cavity  whatever.  At  this  period  the 
ulcers  are  healed  up,  and  the  patient  enjoys  a 
wonderful  use  of  his  swollen  and  deformed 
limb,  but  the  pathological  condition  of  the  bone 
is  still  deserving  of  attention.  At  first  it  is  a 
mass  of  soft  and  spongy  texture.  After  the 
lapse  of  a  few  years,  though  still  clumsy  in 
shape  and  undiminished  in  diameter,  the  bone 
has  become  much  more  firm  and  solid,  and  in 
these  respects,  at  least,  equals  the  original  - 
structure.  At  a  more  remote  period  the  osseous 
part  is  wonderfully  solidified,  being,  in  some 
instances,  as  firm  as  ivory,  and  a  new  medul- 
lary cavity,  with  an  internal  periosteum,  is 
formed.  When  a  transverse  section  of  a  tibia 
so  circumstanced  is  made,  the  osseous  walls 
are  found  to  be  hard,  thick,  and  very  firm,  the 
medullary  cavity  much  narrower  than  in  the 
healthy  bone,  being  scarcely  capable  of  admit- 
ting more  than  a  goose-quill,  and  it  does  not 
seem  to  be  cancellated  or  reticulated,  but  merely 
to  consist  of  one  continuous  cell.  In  this  stale 
the  bone  possesses  nearly  three  times  the 
weight  of  one  in  the  natural  condition,  and 
when  dried  is  of  a  dirty  brown  colour,  never 
assuming  the  white  tint  or  polished  appearance 
of  the  remainder  of  the  skeleton. 

Necrosis  once  formed  is  variable  in  its  pro- 
gress and  indefinite  as  to  the  time  that  may  be 
necessary  to  its  completion.  Sometimes  the 
affection  of  the  bone  is  exceedingly  acute,  ac- 
companied by  external  inflammation  resemb- 
ling phlegmonoid  erysipelas  :  in  these  cases 
the  bone  soon  dies,  the  sequestrum  separates 
and  protrudes  very  rapidly,  perhaps  even  before 
the  new  deposit  has  attained  strength  to  sup- 
port the  limb,  so  that  it  is  necessary  to  preserve 
it  artificially  as  to  shape  and  length  until  the 
process  is  complete.  Within  the  last  year  we 
have  seen  a  case  in  which,  through  neglect  of 
this  precaution,  the  tibia  is  bent  nearly  into  the 
shape  of  the  letter  C.  In  other  instances  the 
disease  is  extremely  tedious,  requiring  years 
before  the  sequestrum  is  either  removed  or  ab- 
sorbed :  we  possess  a  preparation  exhibiting  a 
specimen  of  necrosis  of  more  than  six  years' 
duration,  in  which  the  sequestrum  is  of  a  more 
than  ordinary  size.  Between  these  extremes  of 
great  rapidity  and  as  great  tediousness  there  is 
every  possible  variety,  and  perhaps  these  me- 
dium cases  are  the  most  unfavourable,  for  the 
very  rapid  are  over  before  the  constitution  is 
broken  down,  and  the  very  slow  produce  their 
effects  on  the  system  so  gradually  as  not  to 
make  any  decided  or  severe  impression ;  whilst 
those  which  exhibit  the  symptoms  of  abscess, 
with  an  extraneous  body  working  to  gain  the 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


456 

surface  and  not  able  to  accomplish  it  quickly, 
occasion  much  suffering,  and  if  there  is  ever 
danger  to  life  or  limb  from  the  disease,  such 
cases  are  most  likely  to  produce  it. 

The  sequestrum  or  dead  bone  is  disposed  of 
either  by  presenting  externally  and  permitting 
of  its  removal  by  the  process  of  ulceration  or 
by  manual  operation,  or  else  it  is  never  seen, 
arid  is  entirely  carried  off  by  the  absorbent 
vessels.  Mr.  Russell  accounted  for  the  disap- 
pearance of  the  sequestrum  in  a  very  unsatis- 
factory manner.  He  considered  the  dissolution 
of  the  dead  bone  to  be  "  greatly  accelerated  by 
the  solvent  power  of  the  purulent  matter,"  a 
property,  the  existence  of  which  in  pus  both 
observation  and  experiment  render  question- 
able :  and  when  thus  macerated,  he  conceived 
it  to  be  prepared  to  be  removed  by  absorption 
or  washed  out  by  the  discharge  of  the  matter. 
But,  if  the  surfaces  of  a  sequestrum  are  exa- 
mined, that  which  is  next  to  the  granulations 
of  the  new  bone  will  be  found  to  be  irregularly 
marked  and  indented,  as  if  by  the  action  of  the 
mouths  of  the  absorbents,  whilst  the  other  is 
comparatively  smooth ;  and  as  every  part  ex- 
posed to  the  action  of  the  fluid  should  suffer 
equally  if  the  removal  of  the  osseous  particles 
was  effected  by  maceration,  there  are  strong 
reasons  for  believing  that  the  disappearance  of 
the  sequestrum  depends  not  on  any  power 
chemical  or  mechanical,  but  on  some  vital  pro- 
cess, and  therefore  probably  on  the  action  of 
the  absorbents. 

When  the  sequestrum  presents  externally, 
either  one  end  of  the  bone  (almost  always  the 
superior  one)  protrudes  through  the  soft  parts 
and  remains  there  dry,  hard,  and  dead  for  a 
longer  or  shorter  time,  until  it  becomes  de- 
tached by  the  slow  process  of  nature,  or  is 
separated  by  a  surgical  operation ;  or  else  the 
middle  of  it  presents,  and  can  be  seen  or  felt 
through  an  aperture  in  the  surrounding  new 
bone  whilst  its  extremities  are  confined.  In 
either  case  the  process  of  removal  is  extremely 
tedious.  When  the  end  presents,  it  is  gene- 
rally moveable,  and  seems  as  if  very  little 
force  would  be  sufficient  to  detach  it  altogether ; 
yet  if  an  attempt  is  made  to  pull  it  away,  it  is 
by  no  means  easily  accomplished,  and  a  con- 
siderable time  elapses  between  the  first  pro- 
trusion and  its  final  and  complete  separation. 
When  the  middle  presents,  the  process  is  still 
more  protracted.  All  bones  do  not  seem  equally 
liable  to  necrosis.  Perhaps  the  tibia  is  as  fre- 
quently attacked  as  all  the  other  bones  of  the 
skeleton  taken  together ;  next  in  frequency  is 
the  humerus,  the  bones  of  the  fore-arm,  the 
thigh,  the  clavicle,  and  lastly  the  lower  jaw. 

Thus  far,  it  will  be  seen  that  we  have  con- 
sidered necrosis  as  a  disease,  distinct  and  dif- 
ferent from  every  other  affection  of  the  bones 
whatever,  and  that  its  chief  and  most  marked 
characteristic  is  the  process  of  regeneration. 
Regarded  in  this  point  of  view,  it  is  as  much 
and  even  more  an  action  of  health  than  of  dis- 
ease, and  it  can  easily  be  understood  why  the 
constitution  suffers  so  little,  why  the  hectic 
fever  is  of  so  mild  and  mitigated  a  form,  and 
why  in  a  simple  and  uncomplicated  case  re- 


covery is  nearly  certain.  It  is  also  evident  that 
this  disease  will  not  be  likely  to  occur  in  a 
constitution  contaminated  with  syphilis,  scro- 
fula, scurvy  or  any  of  those  other  vices  which 
the  continental  surgeons  not  only  think  it  may 
be  united  with,  but  which  they  adduce  as  its 
occasional  exciting  causes.  Doubtless,  if  the 
death  of  a  bone  from  any  cause  or  under  any 
circumstances — if  caries,  exfoliation,  and  other 
such  destructive  maladies  are  to  be  included  as 
species  under  the  generic  name  of  necrosis, 
such  affections  may  not  be  inconsistent  with 
the  existence  of  any  poison  or  any  taint ;  but 
if  the  idea  of  a  process  of  reproduction  co- 
existent with  that  of  disease  must  be  admitted 
as  appertaining  to  this  affection,  it  will  be  im- 
possible to  recognise  scrofula  or  syphilis  as 
connected  with  it  in  the  remotest  possible  de- 
gree. Perhaps  we  shall  incur  censure  for  thus 
attempting  to  limit  the  signification  of  the 
term,  but  it  has  been  observed  that  the  nomen- 
clature of  surgical  pathology  is  too  loose  and 
undefined,  and  in  no  instance  is  the  remark 
more  applicable  than  with  reference  to  the  dis- 
eases of  the  osseous  system ;  and  again,  patho- 
logy to  be  useful  must  be  practical,  and  we  can 
by  no  means  assimilate  caries  which  is  so  des- 
tructive of  the  limb  or  fatal  to  life—  or  exfo- 
liation, which  is  always  attended  with  loss  of 
substance — with  necrosis,  the  essential  cha- 
racter of  which  is  a  process  of  reproduction, 
and  its  natural  termination  recovery. 

In  attempting  to  describe,  or  even  to  arrange 
the  remaining  diseases  of  the  osseous  system, 
the  pathologist  has  to  encounter  difficulties  al- 
most insurmountable.  Some  of  these  are  na- 
tural to  and  inseparable  from  the  subject,  as 
1st,  the  depth  at  which  a  bone  maybe  situated 
will  render  it  difficult  to  discover  a  change  of 
shape  or  size,  much  more  to  ascertain  an  altera- 
tion of  structure.  2d.  The  bones  do  not  al- 
ways exhibit  a  very  active  sensibility ;  when 
attacked  by  chronic  forms  of  disease,  they  do 
not  cause  very  great  pain,  and  consequently 
the  evil  may  be  well  established  and  irreme- 
diable before  the  patient  is  fully  sensible  of  his 
condition.  3d.  These  affections  are  not  fatal 
at  an  early  period  ;  they  run  a  long  and  tedious 
course  before  they  destroy  life  or  render  the 
removal  of  the  limb  indispensible.  And  hence 
in  any  individual  case  it  may  be  difficult  to 
learn  even  the  early  history  or  commencing 
symptoms,  much  more  the  nature  of  that  pecu- 
liarity of  constitution  that  disposes  to  these 
diseases,  or  the  first  changes  that  take  place 
from  a  healthy  to  a  morbid  structure.  Little, 
indeed,  can  be  ascertained  with  certainty  as 
to  the  nature  of  osseous  tumours  until  the  part 
has  been  removed,  and  then  the  information 
comes  too  late  for  any  useful  purpose.  Another 
source  of  embarrassment  exists  in  a  want  of  ac- 
cordance as  to  the  nomenclature  of  these  affec- 
tions. One  surgeon  calls  that  exostosis  which 
another  has  named  osteo-sarcoma,  and  a  third 
has  designated  as  cellular  exostosis  an  affection 
which  he  himself  in  another  place  has  named 
spina  ventosa.  In  order,  in  the  present  in- 
stance, to  avoid  similar  confusion,  we  must 
endeavour  to  construct  an  arrangement  which 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


shall  give  to  each  class  of  disease  its  own  ge- 
neric term ;  and  although  occasionally  such 
deviations  from  the  usual  operations  of  nature 
will  present  themselves  to  the  pathologist  as  to 
baffle  all  his  attempts  at  classification,  still  we 
believe  such  a  foundation  as  we  allude  to  will 
be  eminently  useful,  whatever  superstructure 
may  be  raised  upon  it. 

Spina  ventosa. — In  our  museums  of  morbid 
anatomy,  there  is  no  want  of  specimens  exhi- 
biting the  separation,  or  rather  expansion  of 
the  solid  walls  of  a  bone,  leaving  one  or  more 
cavities  within  it ;  these  cavities  having  during 
the  patient's  life  been  filled  with  a  secretion  that 
presents  considerable  variety  in  different  cases, 
sometimes  possessing  a  moderate  degree  of 
firmness  and  consistency,  but  more  frequently 
consisting  of  a  fluid  of  a  serous  character  and 
reddish  colour.  This  is  the  disease  to  which 
we  apply  the  name  of  spina  ventosa  in  contra- 
distinction to  abscess  within  a  bone,  from  which 
it  differs  in  its  extremely  chronic  nature  and 
tedious  progress  ;  in  its  not  containing  purulent 
matter ;  in  its  having  no  tendency  to  burst  into 
any  contiguous  joint;  and  (until  at  a  very  ad- 
vanced period)  in  its  not  being  complicated 
with  caries.*  Boyer  divides  this  disease  into 
two  species,  one  of  which  is  peculiar  to  chil- 
dren, and  continues  to  the  age  of  puberty ;  the 
other,  the  spina  ventosa  of  adults,  which  ex- 
hibits the  characteristic  features  of  the  disease 
more  perfectly. 

It  is,  indeed,  difficult  to  separate  the  first- 
mentioned  of  these  affections  from  our  com- 
monly-received notions  of  caries,  and  in  the 
various  instances  we  have  seen  we  have  always 
regarded  them  as  such.  Boyer  attributes  it  to 
the  influence  of  a  scrofulous  taint  within  the 
system,  and  says  that  it  attacks  the  metacar- 
pus, the  metatarsus,  and  the  phalanges.  It 
commences  and  continues  for  a  length  of  time 
either  without  pain  or  with  very  trivial  suffer- 
ing ;  the  tumefaction  of  the  parts  is  moderate, 
their  motions  scarcely  interfered  with,  and  re- 
covery finally  takes  place  about  the  age  of  pu- 
berty by  a  species  of  necrosis.  Its  course  is 
thus  described  :  "  The  progress  of  the  disease 
and  the  distension  the  soft  parts  undergo,  cause 
them  to  ulcerate  at  a  spot  always  corresponding 
to  some  aperture  in  the  osseous  cylinder,  and 
permitting  the  introduction  of  a  probe  within 
its  cavity.  The  external  aperture  becomes 
fistulous,  and  for  a  Jong  time  discharges  a 
moderate  quantity  of  ill-digested  serous  matter. 
The  part,  however,  remains  indolent,  the  con- 
stitution does  not  suffer,  and  if  the  patient  can 
thus  attain  that  epoch  of  life  at  which  nature 
commonly  can  struggle  with  success  against 
scrofula,  this  form  of  spina  ventosa  may  be 
cured  by  necrosis  of  a  part  of  the  spoiled  bone. 
Then  the  sequestrum  is  detached,  the  re- 
mainder of  the  osseous  parts  subside,  resolu- 
tion is  established,  and  the  disease  ends  by  a 
deep,  adherent,  and  deformed  cicatrix."  We 
have  not  met  with  the  affection  as  here  described 
— we  have  never  seen  any  thing  like  the  rege- 
neration of  a  bone  thus  lost,  nor  can  we  con- 

*  Diet,  des  Sciences  Medicales,  torn.  Hi.  p.  311. 


457 

ceive  necrosis,  which  is  essentially  a  reproduc- 
tive process,  to  be  in  anywise  allied  to  or  con- 
nected with  scrofula ;  we  therefore  still  regard 
this  disease,  which  after  all  is  not  very  frequent 
of  occurrence  in  these  countries,  as  a  modifica- 
tion of  caries. 

"  The  other  species,  fortunately  more  rare 
but  much  more  serious,  most  frequently  attacks 
adult  persons,  and  affects  the  extremities  of  the 
long  and  cylindrical  bones  of  the  limbs."  Its 
exciting  cause  seems  to  be  involved  in  utter 
obscurity,  nothing  being  known  with  certainty 
concerning  it.  Very  often  the  patient  traces  it 
to  the  receipt  of  some  injury,  bnt  it  occurs  so 
frequently  without  any  such  provocation,  that 
it  must  be  considered  as  an  idiopathic  disease. 
It  is  found  most  frequently,  as  Boyer  has  re- 
marked, in  the  long  bones,  where  the  medullary 
cavity  is  best  developed,  but  it  is  seen  in  the 
flat  bones  also,  and  in  so  many  instances  in  the 
lower  jaw  as  to  render  it  an  object  of  attention 
with  reference  to  this  bone  alone.  Its  com- 
mencement has  no  characteristic  by  which  it 
can  with  certainty  be  known,  and  its  progress 
is  equally  variable,  being  generally  slow,  but 
sometimes  remarkably  rapid.  It  commences 
with  pain,  occasionally  deep  and  dull,  occa- 
sionally severe  to  excess,  either  when  its  pro- 
gress is  rapid,  or  it  presses  on  some  sensible  or 
important  part.  This  pain,  with  very  few  ex- 
ceptions, precedes  the  swelling,  and  when  the 
disease  attacks  the  lower  jaw  is  almost  con- 
stantly mistaken  for  common  tooth-ache — a 
mistake  that  leads  to  the  extraction  of  one  or 
more  of  the  teeth  and  the  consequent  exacerba- 
tion of  morbid  action.  The  tumour  seems  to 
engage  the  entire  circumference  of  the  bone,  if 
it  be  a  round  one;  if  flat,  the  swelling  is  more 
oval,  and  sometimes  it  is  irregular  and  lobula- 
ted.  It  is  hard,  firm,  unyielding,  and  incom- 
pressible :  pressure  on  it  does  not  occasion  an 
aggravation  of  pain,  unless  it  shall  have  hap- 
pened that  the  periosteum  is  inflamed,  when 
of  course  the  smallest  pressure  will  occasion 
suffering.  In  the  commencement  it  bears  a 
strong  resemblance  to  necrosis  of  the  long  bone, 
except  in  not  being  preceded  or  accompanied 
by  fever,  and  in  not  being  so  painful  or  so 
rapid  in  its  progress.  In  the  flat  bone  it  has  a 
greater  likeness  to  osteo-sarcoma,  from  which 
it  is  so  difficult  to  distinguish  it  that  many 
cases  of  spina  ventosa  have  been  operated  on 
and  removed  as  examples  of  the  other  disease. 
Nevertheless  at  a  more  advanced  period  the 
diagnosis  is  more  easy,  for  spina  ventosa  does 
not  reach  the  great,  or  rather  the  illimitable  size 
to  which  osteo-sarcoma  may  attain. 

In  a  pathological  point  of  view,  spina  ven- 
tosa should  not  be  considered  as  a  malignant 
disease  :  it  often  endures  for  a  length  of  time 
or  during  life  without  engaging  adjoining 
structures  or  contaminating  the  constitution, 
and  if  removed  by  operation  it  does  not  recur 
in  another  place  or  seize  on  some  other  bone. 
It  is,  moreover,  not  infrequently  capable  of 
relief  or  even  of  cure  by  the  simple  operation 
of  exposing  the  cavity  and  evacuating  its  con- 
tents We  have  at  this  moment  before  us  the 
details  of  a  case  in  which  the  patient  referred  a 


458 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


spina  ventosa  of  the  lower  jaw  to  a  blow  re- 
ceived forty-one  years  previously,  during  the 
last  twelve  of  which  the  tumour  had  been 
opened  or  given  way  spontaneously  three  seve- 
ral times.  In  hospital  it  was  punctured  through 
the  mouth,  and  found  to  consist  of  three  dis- 
tinct cells,  each  containing  its  own  collection 
of  a  fluid  of  the  consistence  of  oil,  varying  from 
a  straw  colour  to  that  of  coffee,  the  darkest 
being  lodged  within  the  largest  cell.  This 
patient,  though  at  the  advanced  age  of  sixty- 
seven,  was  relieved  by  the  operation,  and  left 
the  hospital  convalescent.  If,  however,  by  the 
term  malignant  is  meant  a  disease  that  may 
prove  destructive  of  life  or  limb,  spina  ventosa 
can  occasionally  lay  claim  to  the  title.  For  it 
sometimes  happens  that  small  dark  red  or  pur- 
ple elevations  appear  on  the  surface  of  the  skin, 
which  soon  ulcerate  and  burst,  discharging  a 
quantity  at  first  of  the  material  contained  within 
the  bone,  the  character  of  which  subsequently 
alters  into  a  brown,  unhealthy,  fetid,  and  often 
putrid  sanies.  This  ulceration  is  much  more 
likely  to  take  place  when  the  surface  of  the 
tumour  is  uneven  and  lobulated,  and  at  this 
period  the  disease  in  appearance  bears  no  very 
faint  resemblance  to  fungus  haematodes.  The 
external  sores  next  become  fistulous  and  fun- 
goid ;  they  lead  down  to  the  cavity  or  cavities 
within  the  bone,  and  the  patient,  worn  and 
wasted  by  an  ill-formed  irritative  hectic  fever, 
sinks  exhausted  and  dies. 

Boyer*  in  his  description  recognizes  these 
two  forms  of  spina  ventosa.  "  Sometimes," 
says  this  author,  "  having  attained  a  size  dou- 
ble or  triple  that  of  the  natural  dimension  of 
the  bone,  the  tumour  ceases  to  make  further 
progress  :  it  no  longer  causes  pain  ;  it  does  not 
interfere  with  the  motions  of  the  part,  but  re- 
mains stationary,  and  continues  thus  during 
life,  without  any  alteration  of  the  soft  parts, 
which  accustom  themselves  by  degrees  to  the 
state  of  distension  in  which  they  are  placed. 
But  much  more  commonly  it  continues  to  in- 
crease, until  it  slowly  arrives  at  an  enormous 
size,  still  preserving  its  inequalities  of  surface 
or  acquiring  new  ones."  Having  proceeded  to 
the  period  of  ulceration,  the  conclusion  of  the 
case  is  thus  delineated.  "  Arrived  at  this 
point,  the  local  disease  exercises  a  baneful  in- 
fluence on  the  constitution  of  the  patient:  the 
edges  of  the  fistulous  apertures  become  de- 
pressed and  inverted  towards  the  interior  of  the 
tumour ;  the  discharge  becomes  every  day  more 
copious  and  more  fetid ;  the  fever  which  ap- 
pears commonly  at  the  period  of  ulceration,  but 
which  at  first  is  intermittent  and  irregular, 
comes  at  last  to  be  continued,  and  assumes  the 
character  of  hectic  :  the  pains  are  unceasing, 
and  sometimes  intolerable ;  sleep  and  appetite 
are  deranged  or  lost ;  consumption  establishes 
itself,  and  the  patient  dies  exhausted  and  worn 
out." 

Other  authors,  however,  have  considered 
spina  veutosa  in  all  its  forms  as  a  malignant 
disease.  Such  must  have  been  the  opinion  of 


Mr.  B.  Bell,*  of  Edinburgh,  not  only  from  his 
descriptions,  but  from  the  practice  he  incul- 
cates. "  The  treatment,"  he  says,  "  of  spina 
ventosa  is  very  simple,  as  the  surgeon,  when  he 
is  insured  of  its  existence,  must  at  once  have 
recourse  to  the  amputating  knife.  If  the  dis- 
ease is  seated  in  the  bones  of  the  metacarpus 
or  metatarsus,  as  is  generally  the  case  in  child- 
hood, they  should  be  removed  at  the  articula- 
tions. If  it  has  attacked  the  tibia  and  fibula, 
or  radius  and  ulna,  the  amputation  may  be 
performed  either  at  the  knee  or  elbow,  or  a  short 
way  above  these  joints.  The  general  rule  to  be 
observed  is,  that  the  entire  bone  in  which  the 
disease  has  its  seat  should  be  removed." 

The  morbid  anatomy  of  spina  ventosa  throws 
but  imperfect  light  on  its  pathology,  principally 
because  the  first  and  early  changes  induced  by 
the  disease  are  wholly  unobserved,  and  there- 
fore are  we  ignorant  both  of  the  peculiarity  of 
constitution  that  disposes  to  it,  and  of  the  local 
alterations  that  are  first  developed.  Even  at  a 
more  advanced  period,  when  an  opportunity  is 
afforded  of  examining  the  part  after  death  or 
removal,  there  is  no  striking  uniformity  of  ap- 
pearance. The  bone  itself,  as  Boyer  remarks, 
seldom  seems  to  have  suffered  any  actual  loss 
of  substance  :  on  the  contrary,  it  often  appears 
rather  to  have  gained  in  weight,  the  walls  ex- 
panding and  becoming  thinner  in  proportion  as 
the  cavity  within  increases  in  size.  As  to  the 
number,  size,  and  shape  of  these  cells,  there  is 
an  infinite  variety  as  well  as  in  the  appearance 
of  the  surface,  which  may  be  smooth,  irregular, 
or  lobulated,  and  in  the  character  of  the  mem- 
brane lining  the  cells  and  the  material  secreted 
by  it.  There  is  in  the  museum  of  the  Anato- 
mical School,  Park-street,  Dublin,  a  very  curi- 
ous specimen,  exhibiting  a  perfect  bony  cyst 
developed  within  a  spina  ventosa  of  the  supe- 
rior maxilla,  and  completely  contained  within 
the  expanded  walls  of  the  bone.  It  is  a  very 
remarkable  circumstance  connected  with  these 
alterations  of  structure,  that  although  they  usu- 
ally commence  near  the  extremities  of  the  long 
bones,  they  never  attack  the  joints,  and  conse- 
quently the  motions  of  the  adjacent  articulation 
may  be  but  slightly  impaired,  even  although 
the  size  of  the  tumour  may  be  such  as  to  inter- 
fere with  the  natural  shape  of  the  joint,  and 
render  its  usual  appearance  obscure  and  indis- 
tinct. 

Exottosis. — We  employ  this  term  to  indicate 
certain  tumours  growing  from  the  outer  sur- 
face, or  rather  the  external  structure  of  a  bone, 
in  the  production  of  which  neither  the  medul- 
lary substance  within  nor  the  periosteum  with- 
out have  any  participation.  And  although  our 
notions  of  the  nature  of  the  disease  may  not 
be  perfectly  correct,  and  our  descriptions  lame 
and  incomplete,  we  still  prefer  this  arrange- 
ment in  order  to  separate  the  disease  under 
consideration  from  spina  ventosa  on  the  one 
hand,  and  osteo-sarcoma  on  the  other.  It  will 
be  necessary  also  to  distinguish  it  from  nodes 
and  some  other  affections  of  the  periosteum,  in 


Loc.  citat. 


*  Treatise  on  Diseases  of  the  Bones,  by  Benjamin 
Bell,  edit.  1828. 


DONE,  PATHOLOGICAL  CONDITIONS  OF. 


459 


which  a  deposit  is  found  between  it  and  the 
bone,  or  between  the  laminae  of  this  membrane. 
Exostpsis,  then,  may  consist  of  different  struc- 
tures— of  cartilage  alone — of  cartilage  mixed 
with  some  material  resembling  ligament — of 
cartilage  mixed  with  osseous  structure,  which  is 
by  far  most  frequent  of  occurrence — of  pure 
bone — and  lastly,  of  a  much  harder,  firmer, 
and  closer  substance,  nearly  resembling  ivory. 
It  may  attack  any  bone  whether  flat  or  round, 
and  may  be  found  in  more  than  one  bone  at  a 
time  :  perhaps  the  femur  and  the  tibia  are  most 
frequently  engaged. 

Like  most  other  affections  of  the  osseous 
system,  the  causes  that  lead  to  the  production 
of  this  disease  are  involved  in  the  greatest 
obscurity.  Unquestionably  they  sometimes 
appear  as  the  results  of  accident,  but  then, 
when  other  and  more  severe  injuries  constantly 
occur  without  inducing  such  a  consequence, 
the  unavoidable  conclusion  must  be  that  some 
peculiarity  of  constitution  predisposing  to  the 
disease  exists  in  the  individuals  who  suffer 
from  it.  Exostosis  has  been  seen,  though  not 
frequently,  at  a  very  early  period  of  life ;  it 
has  occurred  idiopathically  and  attacked  several 
bones  in  the  same  individual  at  the  same  time ; 
after  complete  removal  it  has  grown  again  with 
an  inveterate  pertinacity,  and  we  have  seen  it 
in  two  or  more  individuals  of  the  same  family. 
Boyer*  considers  the  venereal  poison  to  be  the 
most  common  cause  of  exostosis,  scrofula  to 
have  but  little  connexion  with  it,  and  scurvy 
still  less.  Other  French  writersf  take  a  more 
extensive  range,  and  adduce  as  causes,  accident, 
cutaneous  affections,  scrofula,  scurvy,  cancer, 
and  venereal.  We  cannot  coincide  with  any 
of  these  opinions.  Scrofula,  when  it  attacks  a 
bone,  produces  a  destructive  caries,  and  not  an 
adventitious  growth;  scurvy,  a  softness  or 
brittleness  of  bone.  If  there  is  any  idiopathic 
disease  of  bone  bearing  the  smallest  resem- 
blance to  cancer,  it  is  osteo-sarcoma,  and  vene- 
real or  even  mercury  we  suspect  to  have  a 
closer  connexion  with  caries  than  exostosis. 

In  every  form  of  exostosis,  no  matter  from 
what  cause  proceeding,  (and  we  have  seen  that 
its  exciting  causes  are  sufficiently  obscure,)  the 
surface  of  the  bone  and  its  substance  to  some 
depth  become  altered  into  a  structure  nearly 
resembling  that  of  the  morbid  growth.  Patho- 
logists  are  not  agreed  as  to  whether  this  altera- 
tion should  be  attributed  in  the  first  instance 
to  an  inflammatory  process  within  the  perios- 
teum or  the  bone  itself.  Mr.CramptonJ  makes 
the  terminations  (as  they  are  technically  called) 
of  chronic  inflammation  of  the  periosteum  to 
consist  in  cartilaginous  thickening  of  the  mem- 
brane, absorption  of  the  subjacent  bone,  or 
the  deposition  of  an  undue  quantity  of  bony 
matter  upon  its  surface,  the  first  and  last  of 
which  are  evidently  forms  of  exostosis.  HOMT- 
ever,  leaving  this  part  of  the  subject,  which 
after  all  is  not  of  much  practical  importance, 
still  unsettled,  it  may  be  remarked  that  whether 

*  Traite  des  Maladies  Chirurgicales,  torn.  iii.  p. 

t  Diet,  des  Sciences  Medicales,  art.  Exostose. 
J  Dub.  Hosp.  Rep.  vol.  ii.  p.  433. 


the  morbid  action  commences  in  the  bone  or 
not,  this  latter  structure  is  always  extensively 
engaged.  Exostosis  is  seldom  to  be  met  with 
like  a  circumscribed  tumour  in  the  soft  parts 
connected  by  a  narrow  neck  or  bounded  by  a 
well-defined  base;  on  the  contrary,  the  bone 
forms  a  considerable  portion  of  the  swelling, 
which  generally  seems  to  spring  gradually  from 
an  extended  portion  of  its  surface. 

The  symptoms  of  exostosis  may  be  arranged 
into  those  produced  by  the  inflammatory  or 
other  diseased  action  within  the  bone  or  perios- 
teum, and  those  occasioned  by  the  pressure  of 
the  tumour  on  the  adjacent  organs.  In  general 
it  is  said  not  to  be  very  painful  nor  very  sen- 
sitive to  the  touch,  but  this  opinion  must  be 
received  with  great  limitation.  We  have  wit- 
nessed the  case  of  a  young  gentleman  who  had 
exostosis  on  the  front  of  both  tibiae.  Here  was 
neither  nerve  to  be  compressed  nor  muscle  to 
be  interfered  with,  yet  the  pain  was  so  great 
that  he  insisted  on  their  removal.  The  part 
was  as  hard  and  firm  as  ivory,  and  removed 
by  the  mallet  and  chisel.  His  sufferings  were 
extreme :  he  was  subsequently  attacked  with 
erysipelas,  and  his  life  brought  into  extreme 
danger,  yet  did  he  not  regret  his  pain  and  the 
risk  he  ran  when  considered  as  the  price  of  the 
relief  he  had  obtained.  The  pain  in  this  case 
could  not  be  regarded  as  the  result  of  pressure 
on  any  very  sensible  structure. 

However,  the  situation  of  the  tumour  may 
not  only  occasion  a  great  aggravation  of  suffer- 
ing, but  be  the  cause  of  very  formidable  occur- 
rences. We  have  seen  a  very  small  exostosis,  not 
larger  than  half  a  marble,  prove  the  apparently 
exciting  cause  of  epilepsy,  which  for  years 
embittered  the  patient's  existence,  and  at  length 
brought  it  to  a  termination.  Indeed,  it  can 
scarcely  be  necessary  to  adduce  instances  in 
order  to  prove  that  morbid  growths  from  the 
internal  table  of  the  skull  may  prove  detrimen- 
tal or  even  destructive  in  a  variety  of  ways. 
Such  growths  from  the  bottom  of  the  orbit  very 
generally  destroy  vision  by  protruding  the  eye 
from  its  socket;  from  the  maxillae  they  may 
interfere  with  respiration  or  deglutition;  and 
in  any  situation  where  there  are  muscles,  they 
must  more  or  less  change  their  direction  or 
otherwise  impair  their  motions.  But  beyond 
this  they  cannot  be  considered  as  malignant — 
they  do  not  involve  adjacent  structures  in  a 
disease  similar  to  themselves,  they  do  not 
ulcerate,  neither  do  they  contaminate  the  sys- 
tem through  the  medium  of  the  absorbents. 
The  vascular  organization  of  an  exostosis  seems 
to  be  inferior  to  that  of  the  bone  from  which 
it  springs,  and  to  the  healthy  structures  whether 
bone  or  cartilage  that  it  may  appear  to  resem- 
ble; its  growth  is  therefore  in  general  slow  and 
its  size  moderate ;  but  its  increase  is  progressive, 
and  there  is  no  limit  to  the  size  it  may  ulti- 
mately attain,  in  this  respect  differing  from  the 
node,  which  soon  attains  its  proper  dimensions 
and  does  not  increase  subsequently.  The  same 
deficiency  of  organization  causes  it  to  endure 
an  attack  of  inflammation  but  badly,  and 
therefore,  when  subjected  to  any  irritation  or 
even  exposed  to  the  influence  of  the  atmos- 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


460 

phere  by  the  ulceration  of  the  superincumbent 
tissues,  it  is  prone  to  fall  into  mortification, 
which  is  one  of  the  methods  by  which  a  natural 
cure  may  be  accomplished.  Not  very  long 
since  a  man  was  operated  on  in  the  Meath 
Hospital  for  the  removal  of  an  ivory-like  exos- 
tosis  from  the  tibia,  but  the  tumour  was  so 
hard  as  to  resist  chisel  and  mallet  and  every 
instrument  that  could  be  employed,  and,  finally, 
the  operation  was  abandoned;  yet  was  the 
case  ultimately  successful,  for  the  exposed 
tumour  sloughed,  exfoliated,  and  the  patient 
left  the  hospital  perfectly  well. 

It  is  remarkable  that  if  the  exostosis  has 
been  removed  by  operation,  the  same  degree  of 
certainty  as  to  its  not  returning  does  not  exist 
as  when  it  has  thus  sloughed  away.  On  the 
contrary,  when  the  tumour  has  been  completely 
extirpated  and  only  the  sound  part  of  the  bone 
left,  a  new  growth  is  often  formed  with  so 
much  certainty  and  rapidity  as  to  justify  the 
expression  we  have  already  used,  of  its  "  grow- 
ing again  with  an  inveterate  pertinacity."  On 
this  subject  we  recollect  a  story  (told,  we  be- 
lieve, by  Bell)  which  might  be  considered  as 
ludicrous  if  it  was  not  but  too  instructive.  A 
dancing-master  had  exostosis  on  both  tibiae ; 
they  gave  him  no  inconvenience,  but  the  de- 
formity was  intolerable  to  his  eyes,  and  he 
thought  it  interfered  with  his  popularity  and 
therefore  with  his  profits.  He  persuaded  a 
surgeon  to  lay  them  bare  and  scrape  them 
down  to  his  ideas  of  genteel  proportion,  but 
unfortunately  the  surgeon  forgot  that  bones 
could  granulate  and  grow.  They  did  so  in 
this  case,  and  after  a  long  confinement  and 
much  suffering  the  last  condition  of  the  patient 
was  worse  than  the  first — the  deformity  was 
much  increased. 

We  distinguish  a  node  from  a  truly  exostotic 
growth  by  the  rapidity  of  its  formation,  by  its 
becoming  stationary  when  it  has  been  formed, 
whereas  the  increase  of  exostosis  is  progressive 
and  may  be  unlimited;  by  its  being  exquisitely 
tender  to  the  touch ;  its  being  subject  to  noc- 
turnal exacerbations,  and  by  its  capability  of 
being  relieved  or  removed  by  medicine  in  a 
great  number  of  instances.  When  composed 
of  osseous  material  alone,  the  almost  stony 
hardness  of  an  exostosis  will  serve  to  distin- 
guish it,  and  when  of  cartilage,  it  is  lobulated 
or  nodulated  on  its  surface,  which  is  never  the 
case  with  respect  to  nodes. 

There  is  a  fungoid  disease  of  the  periosteum 
which,  under  particular  circumstances,  may  be 
mistaken  for  exostosis,  an  error  which  we  have 
witnessed,  and  which  might  be  attended  with 
serious  consequences.  It  is  fortunately  of  very 
rare  occurrence,  and  as  far  as  we  know  has  not 
been  hitherto  described.  In  the  four  speci- 
mens which  have  fallen  within  our  observation, 
its  situation  has  been  in  the  periosteum  of  the 
tibia. 

During  life,  when  covered  by  a  dense  and 
resisting  fascia,  the  tumour  is  very  hard,  its 
growth  slow,  and  not  attended  with  much  pain ; 
neither  is  the  use  of  the  limb  much  impaired, 
as  we  have  known  a  patient  with  this  disease 
travel  on  foot  a  distance  of  six  miles  to  the 


hospital.  When  not  so  restrained,  its  growth 
is  more  rapid :  it  is  softer  to  the  feel,  and  has 
most  of  the  external  characters  of  malignant 
fungus.  Frequently  its  surface  is  lobulated  or 
otherwise  uneven,  when  it  very  much  resembles 
exostosis.  When  the  skin  gives  way  and  ulce- 
rates, or  if  the  tumour  is  unfortunately  cut  into, 
a  bleeding  fungus  protrudes,  that  runs  rapidly 
into  a  gangrene,  which  involves  the  adjacent 
parts;  and  if  the  limb  is  not  speedily  removed, 
the  patient  dies. 

When  examined  after  death  or  removal,  the 
tumour  is  found  to  be  situated  within  the 
laminae  of  the  periosteum.  There  is  a  speci- 
men in  the  museum  of  the  school  in  Park-street, 
in  which  the  membrane  may  be  seen  as  if  split, 
one  layer  passing  in  front  of  the  diseased  mass, 
and  another  still  more  distinctly,  behind,  be- 
tween it  and  the  bone.  The  consistence  of  the 
tumour  is  tolerably  solid  and  firm,  but  not  so 
solid  as  cartilage ;  its  colour  is  white  or  gray, 
and  its  vascular  organization  apparently  very 
deficient.  This  latter  circumstance  is  very  re- 
markable, for  in  some  instances  these  tumours 
exhibit  a  pulsatility  scarcely  inferior  to  that  of 
an  aneurism,  a  symptom  that  may  render  dia- 
gnosis extremely  difficult,  and  which  cannot  be 
explained  by  any  post-mortem  examination. 
The  substance  of  the  bone  beneath  the  tumour 
is  always  removed  by  absorption  to  a  consider- 
able depth. 

Osteo-sarcoma. — This  disease,  as  its  name  im- 
plies, is  a  degeneration  of  the  bone  into  a  sub- 
stance of  a  softer  consistence,  not,  however, 
resembling  flesh ;  or  rather  it  is  an  alteration  of 
structure  accompanied  by  a  deposition  of  new 
material,  and  therefore  attended  by  tumefaction 
to  a  greater  or  less  extent.  As  such,  it  is  evidently 
irremediable  except  by  the  knife,  and  if  there 
is  a  disease  of  the  osseous  system  to  which  the 
term  malignant  can  be  applied,  it  certainly  is 
this.  Its  malignancy,  however,  has  no  resem- 
blance to  that  of  cancer  or  fungus  hsematodes, 
although  like  the  latter  it  very  frequently  attacks 
persons  in  the  earlier  periods  of  life;  but  it 
does  not  involve  adjacent  structures  in  a  disease 
similar  to  itself,  neither  does  it  contaminate  the 
system  through  the  medium  of  absorption.  The 
most  terrific  feature  in  its  character  is  its  ten- 
dency to  recur  after  its  removal  from  one  situa- 
tion, being  in  this  respect  more  formidable  than 
cancer,  which  is,  in  many  instances,  at  first  but 
a  purely  local  disease,  and  may  be  extirpated 
with  complete  success.  This  predisposition  to 
the  disease  is  evidently  constitutional,  but  as 
we  are  totally  ignorant  of  the  circumstances 
that  conduce  to  it,  and  will  probably  remain 
so,  it  is  wholly  uncontrollable  by  medicine  or 
medical  treatment. 

This  disease  may  possibly  affect  persons  at 
every  period  of  life,  although  we  have  not  seen 
it  in  the  aged.  In  children,  particularly  about 
the  fingers,  the  wrists,  the  fore-arm,  &c.  nodu- 
lated swellings  are  frequently  met  with  of  a 
large  size  and  firm  consistence,  which  go  on 
progressively  increasing  until  they  arrive  at  a 
destructive  termination  to  be  described  here- 
after. On  examination  a  tumour  is  found,  the 
external  surface  of  which  is  bone,  as  thin,  it  may 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


be,  as  paper,  and  in  some  spots  nearly  entirely 
absorbed,  evidently  shewing  that  the  morbid 
action  had  commenced  and  increased  from 
within ;  the  substance  of  this  newly-formed  mass 
being  neither  cartilage  nor  ligament,  but  per- 
haps something  between  both,  and  yet  not  so 
entirely  so  as  to  deserve  the  name  of  ligamento- 
cartilaginous,  or  to  be  likened  to  any  natural 
animal  product  whatever.  It  has  been  de- 
scribed by  Bell  as  a  substance  much  resembling 
callus.*  Again,  in  another  specimen  as  it  ap- 
pears in  the  adult,  (in  the  lower  jaw  for  in- 
stance,) the  part  of  the  bone  in  which  the  dis- 
ease commenced  is  completely  spoiled  and 
changed  into  a  mass  of  this  new  material,  assu- 
ming a  rotund  tuberculated  appearance.  From 
thence  downwards,  towards  the  spot  where  the 
bone  is  not  spoiled,  there  is  an  admixture  of 
this  new  material  with  gritty  particles  of  bone 
generally  disposed  in  a  radiated  form ;  the  en- 
tire containing  cells  filled  here  and  there  with  a 
dark-coloured  fluid,  and  traversed  throughout 
by  a  foul  and  fetid  ulceration.  But  osteo-sar- 
comatous  tumours,  although  generally  consist- 
ing of  this  firm  material,  are  by  no  means  so 
invariably.  In  one  remarkable  instance  in 
which  the  disease  occupied  the  femur,  a  vertical 
section  of  the  inferior  end,  which  was  mon- 
strously enlarged,  exhibited  a  mass  of  much 
softer  consistence,  and  eel  Mated  or  porous. 
Its  colour  was  a  mottled  dark  brown,  and  it  re- 
sembled nothing  so  much  as  a  dirty  sponge 
that  had  been  soaked  in  blood  and  matter. 
Sometimes  the  tumour  is  so  soft  as  almost  to 
resemble  brain  :  sometimes  there  are  cysts  con- 
taining fluid  like  blood  :  in  the  long  bones  there 
is  constantly  a  fracture  in  the  centre  of  the  tu- 
mour, or  if  the  swelling  occupies  the  shaft,  the 
articulating  surfaces  are  broken  from  it.f  Very 
often  this  fracture  is,  or  seems  to  be,  the  com- 
mencement of  the  disease. 

We  collect  from  these  observations  and  dis- 
sections that  osteo-sarcoma,  as  we  understand 
the  term,  consists  in  a  morbid  alteration  inte- 
resting the  entire  structure  of  a  bone ;  com- 
mencing in  its  interior,  and  incapable  of  re- 
medy or  removal  unless  by  amputation.  We 
have  already  stated  that  its  chief  malignancy 
consisted  in  some  constitutional  predisposition 
which  originally  led  to  its  formation,  and  in- 
duces a  recurrence  of  it  in  some  other  situation 
after  removal,  and  we  wish  to  examine  into  the 
correctness  of  this  opinion  in  order  to  separate 
it  from  cancer  and  fungus  haernatodes,  because 
some  diversity  of  opinion  obtains  on  this  part 
of  the  subject,  which  after  all  is  the  only  one  of 
practical  importance.  Boyer,J  who  considers 
malignancy  as  constituting  the  very  essence  of 
the  disease,  nevertheless  recognizes  two  species. 
"  In  one,  the  osteo-sarcoma  is  propagated  by 
the  continuity  of  some  cancerous  affection, 
which  had  commenced  in  the  adjacent  soft 
parts,  as  is  seen,  for  example,  in  the  bones 

*  See  Bell's  Principles  of  Surgery,  4to  edition, 
vol.  iii.  part  1. 

t  We  have  taken  the  above  descriptions  entirely 
from  preparations  in  the  school  of  Park-street, 
Dublin. 

J  Traite  des  Maladies  Chirurgicales,  torn.  iii. 


461 


which  form  the  walls  of  the  nasal  fossae,  and 
more  particularly  in  the  superior  maxilla  when 
they  become  spoiled  as  the  result  of  a  hard 
and  cancerous  polypus,  which  had  previously 
existed  for  a  long  time  insulated,  and  without 
any  other  local  affection.  In  the  second  species 
the  bone  is  the  original  seat  of  the  disease,  its 
own  proper  tissue  is  degenerated,  and  the  sur- 
rounding soft  parts  only  partake  of  the  same 
species  of  alteration  consecutively  and  in  a 
secondary  manner."  Dupuytren,*  in  describ- 
ing the  disease  as  it  attacks  the  lower  jaw, 
offers  pretty  nearly  a  similar  opinion.  If,  says 
he,  the  osteo-sarcoma  is  primitive,  it  remains  a 
long  time  confined  to  the  bone,  and  may  ac- 
quire a  very  considerable  volume  before  the 
lips  and  cheeks  are  affected.  It  then  presents 
itself  under  two  principal  forms :  in  the  one, 
the  disease  consists  in  cancerous  fungi,  which 
spring  from  the  substance  of  the  bone,  within 
which  the  disease  is  often  superficial,  that  is,  it 
may  only  affect  the  alveolar  edge  or  the  surface, 
the  body  of  the  bone  remaining  without  any 
enlargement,  and  particularly  its  base  continu- 
ing sound.  The  second  form  is  that  in  which 
the  disease  commences  in  the  centre  of  the 
bone,  which  becomes Jleshy,  and  swells  through- 
out its  entire  thickness.  Most  tumours  of  this 
description  acquire  a  considerable  size,  and  oc- 
casion a  most  repulsive  deformity.  The  teeth, 
loosened  and  displaced,  appear  implanted  here 
and  there  in  the  substance  of  the  bone.  It  is 
impossible  to  close  the  jaws.  The  lips,  dis- 
tended, thinned,  and  closely  applied  to  the 
tumour,  no  longer  retain  the  saliva,  which 
trickles  oft  continually.  It  is,  however,  worthy 
of  remark  that  these  tumours,  or  at  least  many 
of  them,  are  slow  to  ulcerate  or  pass  into  the 
condition  of  cancer.  Sir  A.  Cooperf  has  evi- 
dently made  a  similar  division  of  osteo-sarco- 
matous  tumours,  and  described  them  with  his 
accustomed  accuracy  and  clearness,  but  under 
the  names  of  cartilaginous  and  fungous  exosto- 
sis.  Mr.  Crampton,|  in  his  paper  on  osteo- 
sarcoma,  also  divides  it  into  two  species,  the 
"  mild  and  the  malignant/'  stating,  at  the  same 
time,  that  the  nature  of  either  previous  to  dis- 
section after  removal  or  after  death  is  involved 
in  the  greatest  obscurity.  He  considers  the 
encysted  condition  of  the  tumour,  its  lying  in 
a  bed  of  cellular  tissue  unconnected  with  the 
surrounding  parts,  as  indicative  of  mildness : 
the  characters  of  the  malignant,  as  laid  down 
by  him,  are  evidently  those  of  genuine  carci- 
noma. "  The  soft  bleeding  fungus,  which 
makes  its  way  through  the  integuments  before 
the  tumour  has  acquired  any  very  considerable 
size;  the  profuse  and  peculiarly  fetid  discharge, 
slightly  tinged  with  the  red  particles  of  the 
blood  ;  the  tubercles  of  a  purple  colour  on  the 
surrounding  skin,  which  adheres  firmly  to  the 
subjacent  tumour;  the  pain,  and  above  all  the 
altered  health,  sufficiently  point  out  the  malig- 
nant character  of  the  disease." 

We  have  thus  laid  before  our  readers  the 


*  Le9ons  Orales,  torn.  iv.  p.  636. 

t  Cooper  and  Travers's  Surgical  Essays. 

f  Dub.  Hosp.  Reports,  vol.  iv. 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


462 


opinions  of  the  highest  and  most  respectable 
authorities,  although  we  cannot  coincide  with 
them  in  classing  cancer  as  a  species  of  osteo- 
sarcoma.  Pathologically  they  are  distinct  and 
different  diseases,  appearing  in  patients  of  dif- 
ferent ages,  habits,  and  conditions  of  health, 
and  exhibiting  totally  different  phenomena ; 
and  practically  they  are  not  alike,  for  it  would 
be  as  insane  to  attempt  the  removal  of  a  bone 
contaminated  by  an  adjacent  cancer,  as  it 
would  be  cruel  to  refuse  the  chance  of  an  ope- 
ration to  one  afflicted  with  true  osteo-sarcoma. 
The  disease  is  only^fcalignant  in  its  tendency 
to  re-appear,  nor  can  it  be  previously  ascer- 
tained by  the  symptoms,  or  subsequently  by 
examination  of  the  tumour,  whether  it  is  likely 
to  show  this  disposition  or  not.  Those  nodu- 
lated tumours  that  occur  on  the  fingers  and 
wrists  of  children,  and  which  are  so  admirably 
described  and  delineated  by  Bell,*  almost  in- 
variably reappear  in  some  other  situation  after 
removal.  This  we  have  seen  remarkably  ex- 
emplified in  the  case  of  a  little  girl  who  was 
admitted  into  hospital  with  the  two  fore-fingers 
and  thumb  affected  with  this  disease  :  they 
were  amputated,  but  in  nine  weeks  afterwards 
both  the  radius  arid  ulna  were  attacked,  and 
the  arm  was  cut  off.  In  seven  weeks  both 
clavicles  were  engaged,  and  the  little  patient 
was  sent  to  the  country,  from  which  she  never 
returned.  Besides  the  development  at  an  early 
age,  a  rapidity  of  growth,  accompanied  by  in- 
tensity of  pain,  is  considered  as  indicative  of  a 
most  unfavourable  disposition  in  the  system. 
Yet  is  the  contrary  no  assurance  of  safety,  for 
we  have  seen  a  case  in  which  the  disease  had 
lasted  for  five  years  and  without  much  suffer- 
ing, return  after  removal,  and  destroy  the  pa- 
tient in  less  than  twelve  months.  In  general, 
however,  the  remark  seems  to  be  grounded  on 
experience.  The  presence  of  a  deep  and  foul 
ulceration  within  the  tumour  is  rather  unpro- 
mising :  in  Mr.  Cusack's  six  cases  of  excision 
of  the  lower  jaw,  the  disease  returned  in  one 
only,  and  in  that  this  kind  of  ulcer  had  pre- 
viously existed.  It  may,  too,  be  laid  down  as 
an  unvarying  rule  that  the  secondary  appear- 
ance of  osteo-sarcoma  is  more  painful  and 
more  rapid  in  its  progress  than  in  its  first  and 
original  attack.  It  is  uniformly  fatal. 

The  first  approaches  of  osteo-sarcoma  are 
usually  insidious,  and  as  it  is  in  general  not  a 
very  painful  affection,  it  may  (particularly  in 
children)  escape  observation  at  its  very  earliest 
periods.  Any  bone  may  be  attacked  by  it,  but 
in  the  adult  it  is  more  frequently  situated  in 
the  spongy  extremities  of  the  long  bones  and  in 
the  lower  jaw,  whilst  the  phalanges,  carpal  and 
metacarpal  bones,  the  radius,  the  ulna,  and  the 
clavicle  furnish  the  best  and  most  frequent  spe- 
cimens in  the  younger  subject.  It  occurs  often 
idiopathically,  and  on  the  other  hand  it  occa- 
sionally follows  or  seems  to  follow  a  fracture 
or  other  injury,  as  if  the  disposition  existed  in 
the  system,  and  only  required  some  stimulus 
to  direct  it  to  any  one  situation.  It  commences 
-usually  by  a  small,  firm,  immovable  tubercular- 

*  Loc.  citat. 


like  tumour  appearing  to  spring  from  some  part 
of  the  bone :  soon  after  another  of  these  may 
make  its  appearance,  but  these,  in  the  first  in- 
stance, are  free  from  pain  and  insensible  to 
pressure.  As  it  increases,  the  pain  assumes  a 
dull  and  aching  character,  in  the  jaw  frequently 
mistaken  for  tooth-ache,  in  other  bones  for 
rheumatism .  The  degree  of  suffering,  however, 
is  not  a  very  strong  characteristic,  for  it  will 
depend  on  the  rapidity  of  growth,  the  disten- 
sion suffered,  the  sensibility  of  the  parts  com- 
pressed, and  a  number  of  other  circumstances 
too  obvious  to  require  detail.  In  ordinary 
cases,  it  has  been  remarked  that  the  pain  ob- 
serves a  more  than  progressive  increase  with  the 
size  of  the  tumour,  particularly  if  its  growth  has 
been  accelerated  by  any  accidental  injury.  In 
the  advanced  stages  it  is  always  severe,  and 
m  some  instances  dreadful.  In  one  of  Bell's 
cases,  it  is  stated  that  there  was  no  hour  of  the 
night  or  day  in  which  the  patient's  wild  cries 
could  not  be  heard  miles  off.  In  most  in- 
stances the  sufferer  is  completely  deprived  of 
sleep,  and  in  some  he  complains  of  nocturnal 
exacerbations. 

Once  formed,  it  grows  with  greater  or  less 
rapidity,  often  appearing  stationary  for  some 
time,  and  then  suddenly  and  quickly  increasing : 
sometimes,  on  the  contrary,  it  increases  rapidly 
from  the  commencement,  and  we  have  removed 
an  osteo-sarcoma  of  the  lower  jaw,  which  at- 
tained to  the  enormous  weight  of  4  Ibs.  1  oz. 
avoirdupoise  in  the  short  space  of  eight  months. 
Whilst  the  tumour  is  comparatively  small,  the 
skin  is  pale  and  glassy  and  stretched,  and  blue 
veins  are  seen  meandering  on  its  surface  :  when 
large,  its  colour  is  dark  red,  verging  to  purple, 
and  multitudes  of  these  little  veins  appear  upon 
it.  It  is,  generally,  firm  to  the  touch,  solid 
and  heavy;  but  occasionally  an  examination 
with  the  fingers  discovers  the  osseous  covering 
of  the  tumour  to  be  very  thin,  and  it  yields  on 
pressure  with  a  peculiar  sensation  of  elasticity, 
such  as  one  might  conceive  parchment  to  con- 
vey if  not  stretched  very  tightly.  At  length  it 
gives  way,  and  a  foul  ulcer  is  formed,  dis- 
charging an  unhealthy  fetid  pus,  often  mixed 
with  blood.  The  character  usually  attributed 
to  this  ulceration  is  fungoid,  but  we  have  never 
seen  it  thus.  It  commences  generally  in  the 
centre  of  the  tumour  by  a  slough,  and  gradually 
makes  its  way  outwards  to  burst  by  two  or 
three  apertures,  and  we  have  seen  an  immense 
osteo-sarcoma  of  the  lower  jaw  completely  tra- 
versed by  ulceration,  one  opening  being  in  the 
mouth  and  the  other  at  the  inferior  and  most 
depending  part  of  the  tumour.  These  ulcers 
are  usually  hollow,  attended  with  loss  of  sub- 
stance, and  we  have  not  observed  one  that 
could  have  been  easily  mistaken  for  fungus 
haematodes. 

Independent  of  any  malignancy  inherent  in 
the  tumour,  it  is  evident  that  osteo-sarcoma  may 
destroy  life  by  being  so  situated  AS  to  compress 
some  important  or  even  vital  organ,  more  par- 
ticularly if  such  situation  precludes  the  possibi- 
lity of  removal  by  a  surgical  operation.  Such, 
for  instance,  was  Mr.  Crampton's  case,  in  which 
the  diseased  growth  sprung  from  the  roof  of  the 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


463 


orbit,  projecting  forwards  on  the  eye-ball  and 
backwards  on  the  brain,  both  of  which  organs 
it  must  have  destructively  compressed.*  We 
have  seen  an  osteo-sarcoma  of  the  lower  jaw  in 
a  young  boy  occasion  death  by  suffocation ;  and 
another  in  a  young  female  impede  deglutition 
so  entirely  that  she  died  or  seemed  to  have 
died  of  actual  starvation.  This,  however,  was 
at  a  period  before  an  operation  for  the  removal 
of  the  jaw  had  been  attempted,  at  least  in  this 
country,  and  both  were  considered  as  specimens 
of  fungus  hcematodes. 

When  the  tumour  re-appears  after  operation, 
it  does  so  in  a  very  short  space  of  time,  often 
before  the  wound  has  cicatrized  and  healed; 
and  as  its  situation  is  in  the  immediate  neigh- 
bourhood of  the  former  disease,  the  fungus 
protrudes  through  the  wound,  and  seems  to 
grow  from  it.  In  these  cases  the  progress  to  a 
fatal  termination,  which  is  inevitable,  is  per- 
haps, fortunately  for  the  patient,  extremely 
rapid  also.  Indeed  in  all  cases  of  relapse,  the 
growth  of  the  tumour  goes  on  much  more 
quickly  than  in  the  original  disease,  and  the 
patient's  sufferings  are  considerably  augmented 
also.  We  have  seen  cases  in  which  the  pain 
was  so  intense  and  so  unremitting,  that,  night 
or  day,  not  a  moment's  rest  could  be  obtained, 
even  under  the  influence  of  the  largest  doses  of 
opium  that  could  be  administered  with  safety. 

Cancer.  Fungus  luenuitodes. — We  have  al- 
ready more  than  expressed  a  doubt  that  either 
of  these  diseases  ever  originated  in  the  osseous 
structure,  or  could  be  considered  as  properly 
appertaining  to  it,  although  it  must  be  conceded 
that,  in  a  few  insulated  cases,  a  cancerous  dis- 
position has  seemed  to  produce  a  fragility  of 
bones,  and  that  this  loss  of  the  power  of  resist- 
ance has  preceded  the  development  of  the  dis- 
ease in  the  softer  structures.  But  with  the 
utmost  diligence  of  research  we  have  not  been 
able  to  discover  one  case  in  which  a  morbid 
alteration  of  structure,  analogous  to  those  chan- 
ges in  the  soft  parts  which  we  call  cancer,  and 
which  contaminate  the  system  through  the  me- 
dium of  the  soft  parts,  has  been  found  within 
the  bone  itself,  or  indeed  to  have  existence 
therein,  independent  of  some  similar  degenera- 
tion in  the  adjacent  structures.  On  this  sub- 
ject, however,  our  knowledge  must  be  extremely 
limited.  We  do  not  well  know  what  cancer  is, 
or  what  is  meant  by  a  cancerous  diathesis.  We 
know  not  how  to  define  or  even  to  describe  it 
as  a  generic  form  of  disease.  The  dissection 
of  these  tumours  exhibits  an  almost  infinite 
diversity  of  structure,  and  during  life,  previous 
to  the  actual  contamination  of  the  system,  when 
the  information  too  frequently  avails  but  little, 
it  is  difficult  to  say  whether  any  given  tumour 
possesses  this  quality  of  malignancy  or  not. 
We  therefore  do  not  offer  a  very  positive  or  de- 
cided opinion  on  this  subject. 

But  that  the  bones  in  the  vicinity  of  can- 
cerous disease  often  suffer  from  a  malignant 
and  incurable  species  of  caries,  quite  distinct 
and  separate  from  that  absorption  which  might 
be  the  result  of  pressure,  and  that  this  caries 

*  Dub.  Hosp.  Reports,  vol.  iv. 


illustrates  Mr.  Hunter's  position  of  the  exist- 
ence of  a  cancerous  disposition  in  parts  ap- 
parently sound,  which  will  afterwards  become 
developed  even  though  the  cancer  is  removed 
by  operation,  admits,   we  think,  of  most  irre- 
fragable proof.     Several   years   since,  we  re- 
moved a  very  large  cancerous  ulceration  in- 
volving most  of  the  under  lip,  the  angle  of  the 
mouth,  and  part  of  the  upper  lip  also.     The 
diseased  parts  were   most    unsparingly  taken 
away,  and  a  minute  and  careful  examination 
could  not  detect  the  smallpt  hardness  in  any 
part  of  the  extensive  resu^mig  wound.     Never- 
theless, in  less  than  a  year  afterwards  a  tumour 
appeared  at  the  angle  of  the  jaw,  with  a  hard 
and  unyielding  band  striking  from  it  deeply 
into   the   neck.      The   tumour  increased  and 
pressed  deeply:   an  operation  was  altogether 
out  of  the  question,  and  the  man  died  of  open 
cancerous  ulceration.     On  dissection  the  bone 
was  found  to  be  deeply  and  extensively  eaten 
away  by  caries :    its  entire  structure  was  pre- 
ternaturally  softened,  and  on  attempting  to  dry 
it,  as  an  anatomical   preparation,    its  earthy 
material   crumbled   away  and  was  altogether 
lost.     At  this  moment  we  have  another  case 
affording  a  similar  example  of  cancer  attacking 
the  lower  jaw  after  being  apparently  removed 
from  the   lip.     The   bone    is   swollen,    hardy 
nodulated,  and  extremely  painful ;    but    not- 
withstanding the  urgent  entreaties  of  the  poor 
man,  no  operation  can  be  performed,  and  he 
too  will  die  of  open  cancer.     But  the  point  is 
too  well  understood  by  operating  surgeons  to- 
require  further  elucidation.     Every  one  must 
have   met  with   cases    of    extirpation   of   the 
breast  where  the  ribs  had  been  found  softened 
and  diseased,  although   little  indication  might 
have  previously  existed  of  such  an  unfortunate 
complication. 

But  with  reference  to  fungus  hsematodes 
the  question  is  by  no  means  so  easily  settled. 
In  very  many  cases  of  extirpation  of  the  eye 
in  consequence  of  this  disease,  the  bones  of 
the  orbit,  even  at  a  very  early  period,  have 
been  found  softened,  altered,  and  spoiled,  new- 
arid  more  irritable  growths  have  sprung  from 
their  substance,  and  the  affection  has  re-appeared 
in  a  worse,  because  a  more  incurable  form. 
Operations  about  the  upper  jaw  have  too  fre- 
quently proved  failures  from  a  similar  cause. 
Again,  although  the  immediate  points  of  re- 
ference have  escaped  our  recollection,  we  have 
read  of  cases  of  fungus  haemotodes,  the  very 
first  and  earliest  symptom  of  which  was -a 
fracture  of  the  bone  or  bones  of  the  member 
in  which  the  disease  afterwards  was  extensively 
developed.  In  our  own  note-book  are  two* 
such  cases.  One,  a  poor  boy  admitted  into 
the  Meath  Hospital  in  the  year  1820,  with  the 
most  frightful  enlargement  of  the  thigh  per- 
haps ever  witnessed,  the  circumference  of  the 
limb  being  much  larger  than  that  of  the  body 
of  an  ordinary  man.  He  attributed  the  dis- 
ease to  the  almost  spontaneous  breaking  of  the 
thigh-bone  whilst  he  was  riding  on  an  ass. 
The  tumour  never  ulcerated,  but  as  an  ope- 
ration, even  at  the  hip-joint,  was  decided  on  in 
consultation  to  be  practicable,  he  left  the 


464 


BONE,  PATHOLOGICAL  CONDITIONS  OF. 


hospital,  went  to  the  country,  and  was  lost 
sight  of.  A  case  nearly  similar  occurred 
shortly  afterwards  in  the  shoulder  of  a  young 
woman,  the  first  symptom  of  which  seemed  to 
have  been  a  fracture  of  the  humerus.  Both 
these  cases  were  at  the  time  regarded  as  spe- 
cimens of  fungus  haematodes,  and  as  they  were 
not  examined,  the  question  must  still  remain 
undetermined ;  but  from  what  we  have  since 
observed,  we  should  be  disposed  to  think  they 
were  osteo-sarcoma.  It  is,  perhaps,  right  to 
state  that  many  surgeons  of  high  attainments 
and  great  experience  do  not  separate  these 
diseases  in  their  own  minds,  and  still  regard 
the  affection  of  the  bone,  which  we  would  en- 
title osteo-sarcoma,  as  a  species  of  fungus  hae- 
matodes. 

It  is,  however,  only  in  the  first  and  middle 
stages  that  these  morbid  growths  can  be  easily 
confounded  one  with  the  other.  Both  appear 
small  at  first,  but  increase  with  great  rapidity  ; 
and  both  attain  a  size  not  often  observed  in 
other  tumours,  the  fatty  tumour  alone  ex- 
cepted.  The  same  purple  colour,  the  same 
meandering  of  blue  veins,  and  the  same  in- 
equality of  surface  are  found  on  both ;  and 
when  the  osteo-sarcoma  is  about  to  ulcerate,  it 
may  be  observed  to  be  soft  in  some  places  and 
firm  in  others,  like  fungus  haematodes.  But 
here  the  resemblance  ends.  Throughout  the 
entire  case  the  osfeo-sarcoma  is  harder,  firmer, 
and  more  unyielding:  it  attains  to  a  much 
greater  size  previous  to  ulceration,  and  when 
ulcerated  it  does  not  shoot  out  (at  least  in  its 
more  common  forms)  a  soft  and  spongy  and 
bleeding  fungus;  neither  does  it  destroy  its 
victim  with  such  rapidity. 

In  the  Repertoire  Generate  d'Anatomie  et 
de  Physiologic  Pathologiques  (4  trimestre  de 
1826),  there  is  an  account  of  a  disease  of  the 
tibia  related  by  Lallemand  and  commented  on 
by  Breschet,  who  considered  it  to  be  some 
species  of  aneurismal  tumour,  more  particu- 
larly as  it  is  stated  to  have  been  cured  by  the 
application  of  a  ligature  on  the  femoral  artery. 
The  precise  nature  of  this  tumour,  however, 
is  only  conjectural,  as  it  was  never  demonstrated 
by  dissection  ;  neither  is  it  right  in  the  present 
state  of  our  knowledge  to  question  the  cor- 
rectness of  these  authors'  opinions.  Nature 
sometimes  makes  extraordinary  deviations  from 
the  ordinary  courses  both  of  disease  and  re- 
covery, and  the  circumstance  of  our  inability 
to  explain  the  processes  adopted  by  her  is  not 
sufficient  to  warrant  a  denial  of  their  existence. 
It  may,  however,  be  remarked  that  if  the  case 
alluded  to  was,  as  is  said,  an  aneurism  situ- 
ated within  a  bony  case  and  cured  by  the 
operation  already  stated,  such  recovery  must 
have  been  based  on  principles  totally  different 
from  those  on  which  an  artery  is  tied  in  an 
ordinary  case  of  aneurism. 

In  the  museum  of  the  school  in  Park-street, 
there  is  a  preparation  perhaps  in  some  de- 
gree illustrative  of  this  cellulated  aneurismal 
disease.  It  exhibits  a  morbid  expansion  of 
the  walls  of  a  humerus  removed  from  a  woman 
in  Stevens's  Hospital :  the  entire  shaft  of  the 
bone  seems  to  have  been  engaged,  and  the 


transverse  diameter  of  the  tumour  is  about 
five  inches  and  a  half.  Within  are  a  number 
of  cells  lined  by  a  vascular  membrane  of  an 
exceedingly  dark  red  colour,  the  deep  tinge 
of  which  has  scarcely  been  weakened  by  the 
immersion  of  the  preparation  in  fluid  for  more 
than  seven  years  ;  and  it  is  known  that  during 
life  this  enormous  tumour  imparted  an  in- 
distinct sense  of  pulsation.  It  appears  by  no 
means  improbable  that  the  commencement  of 
this  disease  was  in  the  medullary  membrane, 
which  gradually  became  altered  and  poured 
out  the  material,  whether  blood  or  otherwise, 
with  which  jts  cells  were  filled.  In  proportion 
as  this  accumulated,  the  cells  must  have  en- 
larged and  the  bone  swelled.  In  many  places 
the  external  parietes  are  seen  thinned  down  to 
the  strength  of  parchment  or  paper,  arid  had 
the  disease  been  allowed  to  progress,  they 
might  have  been  removed  by  absorption. 
Had  such  an  event  occurred,  and  the  integu- 
ments subsequently  given  way,  it  is  easy  to 
conceive  that  a  fungus  might  have  sprung  from 
this  vascular  membrane,  which,  occasionally 
pouring  forth  an  abundant  and  incontrollable 
flow  of  blood,  would  in  every  particular  have 
so  far  resembled  fungus  haematodes,  that  even 
an  experienced  practitioner  might  have  found 
it  difficult  to  distinguish  between  them. 

BIBLIOGRAPHY.— Isenflamm,  Anmerk.  Uber  d. 
Knochen,  8vo.  Erlang.  1782.  Bonn,  Thess.  oss. 
morbos.  4to.  Amst.  1783;  Ejus,  Tab.  oss.  morbos. 
fol.  Amst.  1785-87.  Heckeren,  De  osteogenesi 
preternat.  4to.  Lugd.  Bat.  1797.  Boyer,  Lecons 
sur  les  maladies  des  os,  par  Richerand,  2  vol.  8vo. 
Paris,  1803 ;  Anglice  by  Farrell.  Sandifort,  Museum 
anatomicuin.  Weidmann,  De  necrosi  ossium,  fol. 
Frfti.  a  M.  1793.  Augustin,  De  spina  ventosa 
ossium,  4to.  Halae,  1797.  Howship  on  the  morbid 
structure  of  bones,  &c.,  in  Med.  Chir.  Trans, 
vol.  viii.;  Ejus,  Experiments,  &c.  on  fractured 
bones  ;  Op.  cit.  vol.  ix.  and  Sequel  to  the  pre- 
ceding paper  in  Op.  cit.  vol.  x.  *  *  Glisson,  De 
rachitide,  L2mo.  Lond.  1651.  Stanley,  Obs.  on 
bones  in  rickets,  Op.  cit.  vol.  vii.  *  *  Scarpa,  De 
anat.  et  pathol.  ossium,  4to.  Ticin.  1827.  J3.  Bell, 
on  the  diseases  of  the  bones,  8vo.  Edinb.  1828. 
Miiller,  Diss.  de  callo  ossium,  4to.  Norimb. 
1707.  Bohmer,  Diss.  de  ossium  callo,  4to.  Lips. 
1748.  Trqja,  De  novorom  ossium,  &c.  regenera- 
tione,  8vo.  Lutet.  Paris.  1775.  Russel,  Essay 
on  necrosis,  8vo.  Edinb.  1794.  Koehler,  Ex- 
per.  circa  regenerationem  ossium,  8vo.  Gotting. 
1786.  Bonn  u.  Marrigues,  Abhand.  iiber  die  Natur 
und  Erzeugung  d.  Callus,  &c.  8vo.  Leipz.  1786. 
Lebel,  Reflex,  sur  la  regeneration  des  os,  in  Journ. 
Complem.  vol.  v.  Breschet,  Rech.  sur  la  formation 
du  Cal.  4to.  Paris,  1819  (parmi  les  Theses  du 
Concours).  Meding,  Diss.  de  regeneratione  ossium, 
4to.  Lips.  1823.  Kortum,  Exper.  et  obs.  circa  re- 
generat.  ossium,  4to.  Berol.  1824.  *  '  *  *  Spondli, 
Diss.  de  sensibilitate  ossium  morbosa,  4to.  Gotting. 
1814.  Observations  more  or  less  connected  with 
the  subject  of  the  foregoing  article  will  also  be 
found  in  the  surgical  works  of  Bromfeld,  Gooch, 
Pott,  &c.,  in  Meckel's  Handbuch  d.  anatomic  or 
Manuel  d'anatomie,  in  Wilson's  Lectures  on  the 
bones  and  joints,  Lloyd  on  scrofula,  Cooper 8f  Travers's 
Surgical  essays,  Crowther  on  white  swelling,  Cope- 
land  on  the  spine,  Brodie  on  the  joints,  besides  the 
various  articles  already  referred  to  in  the  Diction- 
naire  des  Sciences  Medicales,  papers  in  the  Dublin 
Hospital  Reports,  Dublin  Journal,  Medico-Chirur- 
gical  Transactions,  &c. 

(W.  H.  Porter.) 


*'J 

THE  BRACHIAL  OR  HUMERAL  ARTERY. 


BRACHIAL  OR  HUMERAL  ARTERY 

(arteria  brachialis,  humcraria.  Germ,  die  Ar- 
marterie.)  This  artery  is  the  continuation  of 
the  trunk  of  the  axillary.  It  commences  at  the 
inferior  margin  of  the  tendons  of  the  teres  ma- 
jor and  latissimus  dorsi,  whence  it  extends  to 
about  an  inch  below  the  bend  of  the  elbow, 
where  it  usually  divides  into  the  radial  and 
ulnar  arteries  ;  but  not  unfrequently  this  divi- 
sion takes  place  high  in  the  arm. 

The  brachial  artery  lies  on  the  internal  side 
of  the  arm  above,  but  in  its  course  downwards 
it  gradually  advances  in  an  oblique  direction 
until  it  gets  completely  to  the  anterior  surface 
of  the  limb,  where  it  is  found  situated  nearly 
midway  between  the  condyles  of  the  humerus 
in  front  of  the  elbow  joint ;  it  is  superficial  in 
the  whole  line  of  its  course,  in  every  part  of 
which  its  pulsations  can  easily  be  felt,  and 
sometimes,  in  the  arms  of  thin  persons,  are 
distinctly  visible. 

Relations. — Anteriorly  the  brachial  artery 
is  overlapped,  for  about  its  upper  fourth,  by  the 
coraco-brachialis  muscle  and  the  median  nerve; 
for  the  greater  part  of  its  course  down  the  arm 
it  is  covered  by  the  brachial  aponeurosis,  to 
which  is  added,  where  it  crosses  the  elbow,  the 
falciform  expansion  sent  off  from  the  tendon  of 
the  biceps  to  the  internal  condyle  :  the  median 
basilic  vein  also  lies  in  front  of  it  opposite  the 
bend  of  the  elbow.  Posteriorly,  for  about  a 
third  of  its  length  from  its  commencement  it 
lies  in  front  of  the  triceps,  from  which  it  is  se- 
parated by  a  quantity  of  loose  cellular  tissue 
which  envelopes  the  musculo-spiral  nerve ;  in 
its  inferior  two-thirds  it  rests  on  the  brachiaeus 
anticus.  Internally  it  is  covered  by  the  bra- 
ehial  aponeurosis  at  its  superior  part,  where  the 
ulnar  nerve  is  also  in  contact  with  it.  The  me- 
dian nerve  which  crosses  it,  sometimes  super- 
ficially, and  at  other  times  passing  more  deeply, 
in  the  middle  of  the  arm  gets  to  its  internal 
side,  and  continues  to  hold  this  relation  to  it  in 
the  remainder  of  its  course.  Externally  it  lies 
at  first  on  the  internal  side  of  the  humerus,  from 
which  it  is  separated  as  it  descends  by  the  thin 
muscular  expansion  in  which  the  coraco-brachi- 
alis terminates  at  the  lower  part  of  its  insertion ; 
in  the  remainder  of  its  course  the  inner  edge  of 
the  biceps  bounds  it.  The  fleshy  belly  of  this 
muscle  also  partially  covers  it  in  front,  a  little 
below  the  middle  of  the  arm.  At  the  bend  of 
the  elbow,  the  relations  of  the  brachial  artery 
become  more  numerous  and  complicated ;  here 
it  inclines  obliquely  outwards  and  backwards, 
and  sinks  into  a  space  which  is  bounded  on  the 
inner  side  by  the  origins  of  the  pronator  and 
flexor  muscles  of  the  forearm,  and  on  the  out- 
side by  those  of  the  supinators  and  extensors, 
the  floor  of  which  space  is  formed  by  the  bra- 
chiaeus anticus  muscle,  from  which  the  artery  is 
separated  by  a  layer  of  adipose  cellular  mem- 
brane. The  artery  is  accompanied  in  its  passage 
into  this  space  by  the  tendon  of  the  biceps  and 
the  median  nerve,  the  former  being  situated  to 
its  radial  side,  the  latter  to  its  ulnar ;  and  it  is 
at  the  bottom  of  this  space,  opposite  the  coro- 
noid  process  of  the  ulna,  that  the  subdivision 
of  the  artery  into  radial  and  ulnar  usually  takes 

VOL.  I. 


465 

place.  As  it  enters  the  space  the  artery  is 
crossed  by  the  semilunar  fascia  of  the  biceps,  by 
which  it  is  separated  from  the  internal  cutaneous 
nerve  and  median  basilic  vein.  (For  further  par- 
ticulars on  this  stage  of  the  artery,  see  ELBOW, 
REGION  OF  THE.) 

Two  venae  comites  accompany  the  brachial 
artery  :  they  are  included  in  its  sheath,  and  lie 
one  on  either  side  of  it,  often  communicating 
by  several  transverse  branches  which  cross  the 
artery  in  front. 

So  superficial  is  the  position  of  this  artery 
from  its  origin  till  it  enters  the  region  of  the 
bend  of  the  elbow,  that  it  may  be  exposed  during 
life  in  any  part  of  its  course  with  facility,  and, 
if  the  operator  use  only  common  caution,  with 
safety.  In  all  this  course  the  artery  may  be  felt, 
and  in  the  upper  third  the  operator  may  avail 
himself  of  the  inner  side  of  the  coraco-brachialis 
muscle  as  a  guide,  and  in  the  middle  third,  of 
the  inner  edge  of  the  belly  of  the  biceps.  In 
both  situations  the  operator  has  to  avoid  in- 
juring the  cutaneous  nerves,  and  the  median 
and  ulnar  nerves,  as  well  as  the  basilic  vein, 
which  sometimes  passes  up  as  high  as  the 
axilla.  He  should  also  bear  in  mind  the  po- 
sition of  the  inferior  profunda  artery,  which 
is  sometimes  of  a  large  size;  and  from  its 
direction,  as  well  as  its  relation  to  the  ulnar 
nerve,  presents  a  considerable  resemblance  to 
the  brachial  trunk. 

Brunches. — The  brachial  artery  furnishes  a 
variable  number  of  branches  from  its  external 
side,  none  of  which  is  of  sufficient  importance 
to  be  distinguished  by  a  name ;  they  are  dis- 
tributed to  the  os  humeri,  the  deltoid,  coraco- 
brachialis, biceps,  and  brachiaeus  anticus  muscles, 
and  to  the  integuments.  From  its  internal  side, 
however,  there  usually  arise,  in  addition  to 
several  small  twigs  sent  to  the  triceps,  teres 
major,  latissimus  dorsi,  and  the  integuments, 
three  branches  of  more  considerable  size,  and 
which  derive  their  principal  importance  from 
being  the  leading  channels  of  anastomosis  be- 
tween the  brachial  trunk  and  the  arteries  of  the 
forearm.  These  are,  1,  the  superior  profunda, 
2,  the  inferior  profunda,  3,  the  anastomotica 
magna.* 

1.  The  superior  prof  undo,  (profunda  humeri, 
Haller  and  Soemm.  collaterale  externe,  Boyer, 
grand  musculaire  du  bras,  Chauss.)  arises  from 
the  posterior  side  of  the  brachial  artery,  close  to 
the  border  of  the  axilla.  It  sometimes  comes 
from  the  axillary  artery  by  a  trunk  common  to 
it  and  the  posterior  circumflex,  and  occasionally 
it  arises  from  the  subscapular.  Immediately 
after  its  origin  the  profunda  superior  gives 
several  branches  to  the  coraco-brachialis,  triceps, 
latissimus  dorsi,  teres  major,  and  deltoid  mus- 
cles. Some  of  these  latter,  ascending  towards 
theacromion  process  of  the  scapula,  anastomose 
with  the  thoracica  acromialis,  supra-scapular  and 
posterior  circumflex ;  while  the  branches  sent 
to  the  latissimus  dorsi  and  teres  major  anas- 
tomose with  the  subscapular  artery.  The  supe- 


*  Sometimes  the  subscapular,  and  one  or  both 
of  the  circumflex  arteries,  derive  their  origin  from 
the  brachial. 

2   H 


466 


THE  BRACHIAL  OR  HUMERAL  ARTERY. 


rior  profunda  passes  backwards  between  the  os 
humeri  and  the  long  head  of  the  triceps,  and  in 
company  with  the  musculo-spiral  nerve  enters 
the  spiral  groove  on  the  posterior  surface  of 
the  bone,  passing  between  the  second  and  third 
heads  of  the  triceps.  About  the  middle  of  the 
arm  it  divides  into  two  branches,  the  internal  or 
ulnar,  and  the  external  or  radial.  The  ulnar 
branch  descends  in  the  substance  of  the  triceps 
to  the  olecranon  process,  around  which  it  anas- 
tomoses with  the  posterior  ulnar  and  inter- 
osseous  recurrent  arteries,  having  in  its  course 
supplied  the  triceps  with  several  branches.  The 
radial  branch  comes  forward  with  the  musculo- 
spiral  nerve  as  far  as  the  external  intermuscular 
ligament,  where  it  separates  from  the  nerve 
and  taking  a  more  superficial  course,  descends 
along  the  outer  margin  of  the  humerus  over  the 
supinator  radii  longus  and  the  triceps,  to  which 
and  the  integuments  it  gives  several  branches. 
On  arriving  at  the  external  condyle  it  gives 
branches  to  the  elbow-joint,  and  anastomoses 
with  the  radial  recurrent  in  front,  and  the  recur- 
rent of  the  interosseous  artery  posteriorly. 

Below  the  origin  of  the  superior  profunda  a 
small  artery,  called  nutritia  humeri,  frequently 
arises  either  from  the  superior  profunda  or  the 
brachial  trunk  :  it  enters  the  nutritious  foramen 
of  the  humerus,  and  is  distributed  to  the  can- 
cellated structure  of  that  bone. 

2.  The  inferior  profunda  (ramus  alius  pos- 
terior humeri,  Haller)  arises  from  the  internal 
side  of  the  brachial  artery,  generally  about  the 
lower  part  of  the  insertion  of  the  coraco-brachialis 
into  the  os  humeri ;  passing  backwards,  it  per- 
forates the  internal  intermuscular  ligament,  be- 
hind which  it  descends,  having  the  ulnar  nerve 
internal  to  it  until  it  arrives  at  the  posterior  side 
of  the  internal  condyle,  in  the  grooved  depres- 
sion between  which  and  the  olecranon  it  lies 
close  on  the  periosteum,  and  is  covered  by 
the  ulnar  nerve  :  here  it  divides  into  several 
branches,  some  of  which  are  distributed  to  the 
elbow  joint  and  the  muscles  attached  to  the 
internal  condyle  and  olecranon,  and  it  anasto- 
moses freely  with  the  posterior  ulnar  recurrent 
artery.  Sometimes  the  inferior  profunda  is  a 
branch  of  the  superior  artery  of  that  name ;  it 
varies  very  much  as  to  its  size  in  different 
subjects,  being  sometimes  a  very  insignificant 
twig,  while  in  other  instances  it  is  so  large 
that  it  is  liable  to  be  mistaken  by  an  ope- 
rator for  the  brachial  trunk.  In  reference  to 
this  latter  circumstance  Professor  Harrison  ob- 
serves,* "  In  the  dissected  arm,  the  inferior 
profunda  artery  appears  at  some  distance  from 
the  brachial,  but  if  the  triceps  be  pressed  for- 
ward towards  the  biceps,  so  as  to  place  these 
muscles  as  nearly  as  possible  in  their  natural 
relations,  those  vessels  will  be  found  very  close 
to  each  other ;  so  that,  in  cutting  down  upon 
the  brachial  artery  in  the  middle  of  the  arm,  in 
the  living  subject,  the  inferior  profunda,  from 
its  situation,  and  from  its  being  accompanied 
by  the  ulnar  nerve,  may  be  mistaken  for  the 
brachial.  This  error,  however,  may  be  avoided 
by  recollecting  that  the  brachial  artery  is  the 

t  Surgical  Anat.  of  the  Arteries,  vol.  i.  p.  176. 


nearest  to  the  triceps,  and  is  a  little  covered  by 
that  muscle :  in  general,  also,  there  is  a  material 
difference  in  size  between  the  two  vessels." 

The  remarks  contained  in  the  foregoing  quo- 
tation do  not  apply  to  a  merely  hypothetical 
case,  but  to  one  which  has  actually  occurred  in 
practice,  the  following  instance  of  which  I  once 
had  an  opportunity  of  witnessing.  A  late  emi- 
nent surgeon  undertook  to  tie  the  brachial  artery 
for  the  cure  of  an  aneurism  at  the  bend  of  the 
elbow:  the  inferior  profunda,  which  was  un- 
usually large,  was  exposed  and  tied  on  the 
supposition  of  its  being  the  brachial  artery, 
the  pulsation  in  the  tumour  continuing  un- 
diminished  pointed  out  the  nature  of  the  mis- 
take which  had  been  committed,  and  the  patient 
had  to  submit  to  a  second  operation  at  a  sub- 
sequent period,  in  which  the  brachial  artery  was 
tied  with  a  successful  result  as  to  the  cure  of  the 
aneurism.* 

3.  The  anastomotica  magna,  (ramus  anasto- 
moticus,  Haller,  collaterale  du  coude,  Ch.)  arises 
generally  at  nearly  a  right  angle  from  the  inner 
side  of  the  brachial,  at  a  little  distance  above 
the  elbow-joint.  Several  similar  vessels,  but  of 
much  smaller  size,  arise  from  the  same  source  in 
its  vicinity :  at  first  it  passes  inwards  across  the 
brachiaeus  anticus,  and  perforates  the  internal 
intermuscular  ligament,  giving  branches  to  the 
brachiaeus  anticus,  the  triceps,  the  cellular  tissue 
and  lymphatics  above  the  internal  condyle: 
having  got  upon  the  triceps,  it  descends  to  the 
back  part  of  the  internal  condyle,  where  it 
anastomoses  with  the  inferior  profunda  and 
posterior  ulnar  recurrent  arteries.  When  the 
inferior  profunda  happens  to  be  very  small,  or 
is  absent,  this  vessel  supplies  its  place  by  giving 
branches  to  the  articulation,  to  the  muscles  at- 
tached to  the  internal  condyle,  and  for  anasto- 
mosis with  the  posterior  ulnar  recurrent.  Where 
the  anastomotica  magna  is  absent,  small  branches 
from  the  brachial,  inferior  profunda,  and  ulnar 
recurrent  arteries,  supply  its  place.  When  a 
high  division  of  the  brachial  artery  occurs,  the 
branch  which  is  to  become  the  ulnar  usually 
gives  off  the  two  profundae,  and  the  anasto- 
motica magna:  this  last,  however,  sometimes 
comes  from  the  radial  in  such  cases.f 

*  [Such  a  mistake  as  that  alluded  to  in  the  text 
may  likewise  occur  where  there  has  been  a  high 
bifurcation  of  the  brachial  artery. — ED.] 

t  [The  frequent  occurrence  of  irregularity  as  to  the 
position  at  which  the  brachial  trunk  divides  into  its 
terminal  branches,  the  radial  and  ulnar,  constitutes 
a  point  of  great  interest  in  the  anatomical  history 
of  this  artery.  I  believe  it  may  be  said  that  it  never 
happens  that  the  bifurcation  takes  place  below  the 
coronoid  process  of  the  ulna  ;  on  the  contrary,  the 
division  above  that  point  is  by  no  means  uncommon, 
occurring,  according  to  the  calculation  of  Professor 
Harrison,  once  in  every  four  subjects.  This  bifur- 
cation occurs  at  all  points  in  the  arm,  and  in  some 
cases  the  radial  and  ulnar  arteries  proceed  at  once 
from  the  axillary.  In  general  the  anomalous  artery 
is  the  radial,  and  is  subcutaneous  in  its  course, 
while  the  ulnar  follows  the  normal  course  of  the 
brachial  trunk.  Sometimes  the  reverse  is  the  case  : 
sometimes  both  radial  and  ulnar  are  subcutaneous, 
and  sometimes  the  radial  is  at  its  origin  ulnad, 
but  afterwards  crosses  the  ulnar  artery  at  a  very 
acute  angle,  to  get  to  the  radial  side.  In  some  rare 
cases  the  brachial  artery  is  regular  in  its  course, 


BURSJE  MUCOS7E. 


467 


Anastomoses. — The  ascending  branches  of 
the  superior  profunda  anastomose  in  the  sub- 
stance of  the  deltoid  muscle  with  the  anterior 
and  posterior  circumflex  and  the  cephalic  branch 
of  the  acromial  thoracic,  and  with  the  subsca- 
pular  and  the  axillary  branches  of  the  thoracica 
longior  in  the  axilla.  If  the  brachial  artery  be 
obliterated  by  disease  or  the  application  of  a 
ligature  above  the  origin  of  the  superior  pro- 
funda, the  blood  will  be  carried  by  the  circuitous 
route  of  these  anastomoses  into  the  brachial 
artery  and  all  its  branches  from  the  superior 
profunda  downwards. 

When  the  brachial  artery  is  obliterated  near 
the  elbow,  the  circulation  is  maintained  in  the 
forearm  and  hand  by  the  anastomoses  of  both 
profundae  and  the  anastomotica  magna  with  the 
recurrent  branches  of  the  radial,  ulnar,  and  in- 
terosseous  arteries.  The  anastomosis  kept  up 
between  all  the  branches  of  the  brachial  artery 
along  the  periosteum  of  the  humerus,  in  the 
substance  of  the  muscles  and  in  the  integu- 
ments of  the  arm,  is  so  free  as  to  be  sufficient 
to  ensure  the  circulation  in  the  limb  even  if  the 
brachial  artery  were  obliterated  throughout  the 
whole  of  its  length. 

For  the  BIBLIOGRAPHY,  see  that  of  ANATOMY 
(INTRODUCTION)  and  of  ARTERY. 

(J.  Hart.) 

BRAIN.  See  BNKEPHALON,  and  NERVOUS 
SYSTEM  (CoMP.  AN  AT.) 


MUCOS^l.  (Fr.  bourses  synovi- 
ales;  Germ,  die  ShleimbeutelS) — This  name  was 
first  given  by  Albinus  to  small  shut  sacs,  filled 
with  an  unctuous  fluid,  which  he  found  in 
certain  parts  of  the  body,  interposed  between 
the  tendons  and  bones.  The  name,  however, 
is  now  much  more  extensively  applied,  for  ana- 
tomists have  ascertained  that  those  smooth 
membranes,  previously  noticed  by  Winslow, 
covering  the  tendons  and  lining  the  tendinous 
sheaths  about  the  wrists  and  ankles,  are  strictly 
of  the  same  nature  as  those  described  by  the 
Dutch  anatomist.  The  number  of  bursse  known 
to  Albinus,  and  described  by  him  in  his  "  His- 
toria  Musculorum,"  was  but  sixteen  pairs. 
Monro,  who  first  properly  explained  their  ana- 
tomy and  uses  in  his  excellent  monograph  upon 
this  subject,  has  made  us  acquainted  with  no 
less  than  seventy  pairs,  all  situated  in  the  ex- 
tremities :  and  since  his  day  the  number  has 
been  further  increased  by  the  discoveries  of 
Beclard  and  others  :  so  that  anatomists  are  now 
acquainted  with  upwards  of  one  hundred  pairs, 
many  of  them  situated  in  the  head  and  trunk. 

Bursae  mucosae,  though  of  the  same  structure 
and  answering  the  same  ends  in  every  situation 

but  gives  off  the  interosseous  high  up,  which  has 
all  the  appearance  and  many  of  the  dangers  of  the 
high  bifurcation.  Mr.  Harrison  mentions  a  case 
in  which  the  brachial  divided  into  three  branches, 
two  of  which  united  to  form  the  radial,  which  gave 
off  the  anterior  interosseous,  the  posterior  being 
derived  from  the  third,  the  ulnar.  Mr.  Burns  re- 
marks, that  when,  as  rarely  happens,  the  ulnar 
is  the  anomalous  branch,  the  bimrcation  generally 
takes  place  nearer  the  axilla,  than  when  the  radial 
is  the  abnormal  vessel. — ED.] 


where  they  occur,  may  nevertheless  be  divided, 
with  advantage,  into  two  great  classes;  viz., 
I.  the  subcutaneous  bursts,  or  those  placed  be- 
tween the  skin  and  fascia  ;  and,  II.  the  deep 
bursts,  or  those  which  lie  beneath  the  latter 
membrane. 

I.  The   subcutaneous   or   superficial   bursts 
were  unknown  not  only  to  Albinus,  but  even  to 
Monro  and  Bichat ;  at  least  there  is  no  mention 
made  of  them  in  the  works  of  any  of  these 
authors.     Beclard,  in   his   "Additions  to  the 
General  Anatomy  of  Bichat,"  appears  to  be 
the   first    anatomist  who    refers   distinctly   to 
them.     The  most  remarkable  are, — 1,  a  large 
one   placed   between  the   skin  and  the   liga- 
mentum  patellae;  2, one  between  the  skin  and 
fascia  covering  the  great  trochanter  of  the  femur; 
3,  one  between  the  skin  and  fascia  over  the 
olecranon.  These  are  all  extremely  well  marked. 
There  are  others  likewise,  which,  though  less 
perfectly   developed,  are,  however,   evidently 
of  the   same   nature ;    such  as   that  between 
the   skin    and   fascia    over  the   angle   of  the 
lower  jaw,  and  those  found  upon  the  dorsum  of 
the   hand  beneath  the  phalangeal   and    meta- 
carpo-phalangeal  articulations.    These   super- 
ficial bursae  are  not  equally  perfect  in  all  in- 
dividuals:   they  are  best  developed  in  those 
whose  limbs  are  actively  and  habitually  exer- 
cised.    On  cutting  into  their  cavities  we  gene- 
rally find  them  traversed  by   numerous  fila- 
ments :    the    appearance   indeed  is  extremely 
similar  to  that  presented  by  the  subcutaneous 
cellular  tissue  in  certain  parts  of  the  body, — in 
the  palpebra  and  penis,  for  example ;  and  this 
no  doubt  is  the  reason  why  these  bursae  were 
not  distinguished  from  cellular  membrane  by 
Monro  and  others.     That  they  are  different 
structures,  however,  or  at  least  that  they  are 
independent  of  the  cellular  system,  is  sufficiently 
proved  by  the  simple  process  of  inflating  their 
cavities  through  a  small  opening  made  into  them ; 
we  then  find  that  the  air  is  circumscribed  within 
a   definite   boundary,  and   cannot,   as  in    the 
palpebra  and  penis,  be  made  to  pass  into  the 
surrounding  cellular  membrane. 

II.  The  deep  bursts,  or  those  placed  beneath 
the  fascia,  are  much  more  numerous  and  much 
better  marked  than  the  preceding.     They  are 
almost  uniformly  found  in  connexion  with  ten- 
dons, and,  generally  speaking,  are  interposed 
between  them  and  the  bones  over  which  they 
play.     Like  the  superficial  ones,  they  too  are 
always  shut  sacs,  in  most  instances  of  an  ex- 
tremely simple  form,  but  in  some  cases  much 
more  complex ;  and  hence  they  may  with  pro- 
priety be  subdivided  into  two  sets, — the  vesi- 
cular and  the  vaginal. 

a.  The  deep  vesicular  bursts,  when  fully  dis- 
tended, represent  each  a  simple  globular  bag,  one 
of  whose  sides  is  in  contact  with  the  bone,  and 
the  other  with  one  side  of  the  tendon,  without, 
however,  enveloping  it.  (See  Jig.  11 1,  b.)  On 
opening  into  its  cavity,  it  is  found  to  con- 
tain a  viscid  fluid,  more  or  less  abundant, 
and  this  is  sometimes  traversed  by  fila- 
ments passing  from  one  wall  of  the  sac 
to  the  other.  They  generally  occur  in  the 
neighbourhood  of  the  great  articulations  of 
2  ii  2 


468 


BURSAE,  MUCOS^E. 


the  hip,  shoulder,   knee,  and  ankle,  but  are 
not,  as  it  was  supposed  until  of  late  years,  con- 
fined to  the  extremities,  for  we  shall  presently 
point  out  instances  of  their  occurrence  both  in 
the  head  and  trunk.    Amongst  the  most  re- 
markable in  the  inferior  extremity  we  find,  in 
the  neighbourhood  of  the  hip-joint,  a  very  large 
one  between  the  tendon  of  the  psoas  muscle 
and  the  capsular  ligament ;  a  large  one  between 
the    great  trochanter  and  gluteus   maximus; 
one  between  the  gluteus  maximus  and  vastus 
externus;  one  between  the  gluteus  medius  and 
trochanter;  one  between  the  gluteus  minimus 
and  trochanter;  one  between  the  pectineus  and 
femur.    These  are  all  large  and  regular  in  their 
existence ;  but  there  are  other  smaller  ones  fre- 
quently met  with,  particularly  at  the  posterior 
part  of  the  joint  connected  with  the  small  ten- 
dons and  muscles  placed  there.      About  the 
knee-joint  there  are  likewise  several  vesicular 
burs»  :  immediately  above  the  articulation,  be- 
tween the  extensors  and  front  of  the  femur, 
there  is  an  extremely  large  one,  oftentimes  ex- 
tending several  inches  upwards,  and  still  more 
remarkable  in  many  instances  for  communi- 
cating with  the  synovial  membrane  of  the  joint; 
a  fact  which  has  been  well  appealed  to  by  the 
general  anatomist  in  proof  of  the   anatomical 
identity  of  these  two  structures.     There  is  a 
large  one,  likewise,  at  the  inner  and  lower  part 
of  the  articulation  between  the  tibia  and  the 
tendons   of  the  sartorius,   gracilis   and   semi- 
tendinosus :  posteriorly  between  the  origins  of 
the  gastrocnemii  and   the  bone  there  is  also 
found  a  bursa;  and  a  similar  one  between  the 
popliteus  muscle  and  the  joint.     These,  like 
the  large  one  in  front,  generally  communicate 
freely  with   the  articular  synovial  membrane. 
There  is  also  a  bursa  generally  found  between 
the  semi-membranosus  and  the  internal  lateral 
ligament.     Around  the  ankle  there  are  but  few 
vesicular  bursae  :  posteriorly,  however,  between 
the  tendo  Achillis  and  os  calcis,  there  is  found  a 
very  large  one ;  and  smaller  ones  are  frequently 
met  with   connected   with  the  flexor   pollicis 
longus,  and  some  of  the  other  muscles  in  their 
passage  here.    In  the  superior  extremity  we  find, 
likewise,  several  vesicular  bursae :  around  the 
shoulder-joint  there  is  a  very  large  and  regular 
one  placed  between  the  deltoid  muscle  and  the 
capsular  ligament;   there  is  one  between  the 
clavicle  and   coracoid  process;    one   between 
the  scapula  and  subscapular  muscle ;  one  be- 
tween the  subscapular  muscle  and  the  capsule. 
Lower   down   there   is   a  bursa  between  the 
humerus  and  the  tendons  of  the  teres  major 
and   latissimus  dorsi;   and  also  a  bursa  fre- 
quently between  these  two  tendons,  at  a  little 
distance  from  their  insertion.    About  the  elbow- 
joint  there  is  a  vesicular  bursa  between  the 
tendon    of   the    triceps    and    the   olecranon; 
one  in  front,  between  the  tendon  of  the  biceps 
and  the  tubercle  of  the  radius  :  there  is  also 
one  between  the  head  of  the  radius  behind,  and 
the  extensor  muscles  passing  over  it.     Around 
the  wrist-joint  there  are  no  vesicular  bursse  of 
any  size  or  importance.     There  is  in  the  trunk 
a  large  vesicular  bursa,  usually  found  between 
the  latissimus  dorsi  and  scapula.     In  the  head 


we  often  see  a  distinct  bursa  interposed  between 
the  two  divisions  of  the  masseter  muscle. 

b.  The  deep  vaginal  bursa  are  invariably 
found  connected  with  tendons  and  with  the 
fibrous  sheaths  through  which  these  tendons 
are  transmitted.  They  are  somewhat  more 
complex  than  the  preceding,  for  instead  of 
representing  a  simple  shut  sac,  they  form,  like 
serous  membranes,  by  reflexion  a  double  sac, 
one  of  whose  portions,  corresponding,  for  ex- 
ample, to  the  plura  costalis,  lines  the  interior 
of  the  fibrous  sheath,  while  the  other,  answering 
to  the  plura  pulmonalis,  invests  the  surface  of 
the  tendon.  There  is,  however,  this  difference 
between  the  pleurae  and  the  synovial  sac,  that  in 
the  latter  there  is  no  longitudinal  septum,  no 
mediastinum  resulting  from  the  reflexion  of  the 
membrane ;  for  the  reflexion  occurs  not  along 
the  channel,  but  at  either  extremity  of  the 
fibrous  sheath:  thus  the  bursa,  if  completely 
detached  from  all  surrounding  structures,  would 
represent  a  large  tube,  containing  within  itself 
a  smaller  one ;  these  two  being  continuous  by 
their  extremities  alone. 

The  deep  vaginal  bursae  generally  occur  in 
the  neighbourhood  of  ginglymoid  articulations, 
and  by  far  the  largest  and  most  interesting  are 
those  connected  with  the  flexor  tendons  of  the 
wrist  and  ankle.  They  are  always  of  very  great 
size,  not  only  passing  a  considerable  way  up- 
wards upon  the  forearm  and  leg,  but  likewise 
extending  downwards  into  the  palm  of  the  hand 
and  sole  of  the  foot,  and  branching  out  at  their 
distant  extremity  into  several  distinct  sheaths 
for  the  respective  tendons  belonging  to  the 
different  toes  and  fingers.  Upon  the  phalanges 
the  synovial  sheath  is  firmly  bound  down  by 
a  dense  unyielding  fibrous  membrane,  a  cir- 
cumstance well  worthy  of  remark;  for,  as  we 
shall  presently  see,  it  modifies  in  a  very  im- 
portant degree  the  characters  of  inflammation 
occurring  here.  Besides  these,  we  have  a  re- 
markable vaginal  bursa  connected  with  the  long 
head  of  the  biceps  muscle;  and  smaller  ones 
are  found  investing  the  tendons  of  the  circum- 
flexus  palati,  obturator  internus,  &c. 

Having  thus  considered  the  forms  and  rela- 
tions of  the  different  sorts  of  bursae,  we  may 
next  proceed  to  offer  a  few  remarks  applicable 
alike  to  all,  upon  their  structure,  contents,  uses, 
development,  and  diseases.  Here,  however,  our 
labour  is  much  abridged  by  the  fact  already 
alluded  to,  and  now  admitted  upon  all  hands, 
that  the  membrane  forming  the  bursae,  and  the 
synovial  membrane  of  joints,  are  anatomically 
and  physiologically  the  same.  They  are,  in 
fact,  the  same  in  form,  being  both  shut  sacs ; 
the  same  in  structure,  being  both  essentially 
composed  of  cellular  membrane;  the  same  in 
function,  for  they  are  both  designed  to  facilitate 
the  motion  of  contiguous  organs ;  and,  as  we 
shall  presently  see,  they  are  both  similarly  af- 
fected by  disease.  Were  we  to  enter  at  length 
into  these  particulars  upon  the  present  occasion, 
we  should  but  anticipate  details  belonging  pro- 
perly to  a  more  general  head,  that,  namely,  of 
synovial  membrane.  Hence  the  few  remarks  we 
are  now  about  to  offer  must  be  received  as  merely 
supplementary  to  those  found  under  that  article. 


BURS7E 

1.  Structure. — The  opinion  of  Haller,  that 
these  membranes  are  ultimately  composed  of 
cellular    substance,    though    controverted    by 
Monro  and  others,  is,  however,  now  universally 
admitted.     They  are,  in  fact,  like  all  synovial 
membranes,  essentially   composed  of  cellular 
substance,  entirely  destitute  of  fibre,  scantily 
supplied  with  vessels,  and  remarkable  for  their 
softness   and   flexibility.      The  vaginal  bursae 
are,  however,  much   more  delicate    than   the 
vesicular.      The  fatty    bundles,   mistaken   by 
Havers  for  glands,  are  frequently  found  in  their 
substance.      Rosenmiiller    speaks   of   distinct 
synovial  follicles  as  likewise  demonstrable,  but 
the  existence  of  any  such  bodies  appears  to  us 
more  than  doubtful. 

2.  Contents. — Experiments  have  been  made 
by  Monro  and  others,  to  shew  that  the  fluid 
contained  in  bursae  is  similar  to  that  contained 
in  synovial  membranes.     These,  however,  may 
now  be  looked  upon  as  superfluous,  inasmuch  as 
this  question  has  merged  in  the  general  one,  viz  , 
the  identity  of  the  two  structures.     Chemistry, 
in  fact,  has  proved  that  their  fluid  and  that  of 
synovial  membranes  are,  if  not  completely,  at 
least  essentially  the  same.    In  the  subcutaneous 
bursae  it  is  scanty  and  thin;  in  the  larger  and 
deeper  ones  it  is  said  to  be  somewhat  more 
viscid. 

3.  Function. — The  use  of  bursae   is  in  all 
cases  the  same;  they  serve  to  isolate  certain 
parts  and  facilitate  the  motions  performed  by 
them :    hence   they  are  found   only   in  those 
situations  which  are  the  seat  of  motion.     Their 
fluid,  from  its  oily  consistence,  must  of  course 
tend  considerably  to  diminish  the  effects  of  fric- 
tion. 

4.  Development. — Bursae  are  developed  at  a 
very  early    period,    and   are    relatively   more 
pliant  and   perfect  in  the  child  than  in   the 
adult,   to   facilitate,  as   it  would  appear,  the 
almost  incessant   movements   natural  to   that 
period  of  life.     They  become  more  dense  and 
unyielding  in  the  adult,  and  in  extreme  old  age 
are  said  to  become  dry  and  rigid.     This,  no 
doubt,  is  amongst  the  causes  which  render  the 
movements  of  old  age  slow  and  laboured.     A 
curious  fact  connected  with  this  subject  is  the 
accidental  development  of  bursae  in  cases  where 
their  presence  becomes  necessary.     When  the 
superficial  bursa  in   front  of  the  patella  has 
been  removed  by  operation,  its  place  is  ulti- 
mately supplied,  as  Sir  Benjamin  Brodie  has 
seen,  by  a  newly  formed  one,  similar  in  every 
respect  to  the  original  sac.     In  cases  of  club- 
foot  a  large  subcutaneous  bursa  has  been  found 
developed  upon  that  portion  of  the   swelling 
which  has  been  the  chief  seat  of  pressure  and 
motion:    and   in  cases  of  diseased  spine,  at- 
tended with  considerable  angular  curvature,  a 
bursa  has  become  developed  between  the  pro- 
jecting spinous  process  and  the  skin. 

PATHOLOGICAL  CONDITIONS  OF  BURS.E  MU- 
cos^. — Bursae  mucosae,  superficial  as  well  as 
deep,  are  not  unfrequently  the  seat  of  inflamma- 
tion, resulting  either  from  external  causes,  such 
as  cold  or  local  injury,  or  from  constitutional 
causes.  In  the  majority  of  cases  inflammation  in 
these  structures  assumes  a  chronic  form,  and  its 


469 

ordinary  effects  are  either  to  increase  the  quan- 
tity of  the  synovial  fluid,  to  determine  the 
effusion  of  a  turbid  serum  loaded  with  flakes  of 
lymph,  or  to  end  in  the  formation  of  matter. 

The  general  phenomena  of  bursal  inflamma- 
tion may  be  studied  with  most  advantage  in  the 
large  subcutaneous  bursa  in  front  of  the  knee- 
joint  :  it  is  more  frequently  inflamed  than  any 
other  in  the  system.  This,  however,  is  not 
owing  to  any  peculiarity  of  structure  predis- 
posing it  to  disease,  but  merely  to  the  accidental 
circumstance  of  its  situation,  which  exposes 
it  more  than  any  other  to  external  injury.  In 
those  persons  who  continue  for  a  long  time 
in  the  kneeling  attitude,  in  devotional  exer- 
cises for  example,  and  still  more  remarkably 
in  those  whose  occupation  obliges  them  not 
only  to  support  the  body  but  also  to  move 
upon  the  knees  (as  carpenters,  housemaids, 
and  others),  inflammation  of  this  bursa  is  very 
frequently  met  with.  In  many  instances  it 
occasions  little  general  or  local  disturbance, 
merely  causing  "an  increased  effusion  of  the 
proper  synovial  secretion,  without  producing 
any  change  whatever  in  its  natural  properties. 
In  other  cases  the  fluid  is  not  only  increased 
in  quantity,  but  becomes  changed  likewise  in 
quality ;  it  assumes  the  appearance  of  a  turbid 
serum,  with  numerous  flakes  of  lymph  floating 
in  it;  or  where  the  disease  has  been  of  long 
standing,  the  fluid  is  frequently  found  loaded 
with  a  number  of  loose  bodies,  almost  of  the 
consistence  of  cartilage,  and  of  a  flattened  oval 
form.  Sir  Benjamin  Brodie  compares  their 
appearance  not  inaptly  to  that  of  melon-seeds, 
and  he  considers  them  as  portions  of  lymph 
originally  of  an  irregular  shape,  but  which,  by 
the  motions  and  pressure  of  the  surrounding 
parts,  have  had  their  angles  worn  off,  and 
assumed  by  degrees  a  firm  consistence.  They 
have  been  found  likewise  in  the  smaller  bursae. 
Monro  has  seen  upwards  of  fifty  extracted  from 
the  small  bursa  of  the  flexor  pollicis  longus 
tendon,  where,  by  excessively  distending  the 
surrounding  parts,  they  had  produced  severe 
pain.  When  the  great  vaginal  bursae  of  the 
flexor  tendons  have  become  the  seat  of  effusion, 
a  very  remarkable  appearance  may  present  itself, 
at  once  explicable,  however,  by  referring  to  the 
anatomy  of  the  part.  The  fluid  can  by  pressure 
be  forced  downwards  under  the  annular  liga- 
ment, and  into  the  palm  of  the  hand,  and  thence 
upwards  again  into  the  forearm.  Some  authors 
have  deemed  it  proper  to  designate  by  a  par- 
ticular name  this  termination  of  the  disease  by 
effusion,  and  the  words  thygroma  and  ganglion 
have  been  applied  with  a  good  deal  of  con- 
fusion by  different  persons;  but  it  appears  to 
us  that  there  exists  no  necessity  for  a  specific 
name  to  refer  to  this  accidental  mode  in  which 
inflammation  terminates. 

A  much  more  important  termination  of  the 
disease  is  that  in  which,  owing  to  local  or  con- 
stitutional causes  above  alluded  to,  the  inflam- 
mation, having  run  a  severer  course,  ends  in 
suppuration.  Sir  Benjamin  Brodie  has  in  this 
case  observed  that  the  matter  may  take  either 
of  two  courses  :  it  may  come  directly  to  the 
surface  ;  or,  without  pointing  forwards,  it  may 


470 


CARNIVORA. 


penetrate  the  side  of  the  sac,  and  so  become 
extensively  diffused  through  the  surrounding 
cellular  membrane,  involving  the  whole  anterior 
and  lateral  portions  of  the  joint.  In  such  a 
case  the  practitioner  is  very  liable  to  be  de- 
ceived as  to  the  true  character  of  the  abscess, 
and  to  confound  it  with  those  which  originate 
in  the  cellular  membrane. 

There  are  certain  cases  in  which  acute  inflam- 
mation of  a  bursa  becomes  even  a  more  serious 
disease  than  that  just  alluded  to.  In  the  syno- 
vial  sheaths  of  the  flexor  tendons,  for  example, 
the  progress  and  termination  of  the  inflamma- 
tion are  often  modified  in  a  remarkable  manner 
by  the  anatomical  peculiarities  of  that  part.  In 
that  form  of  the  paronychia  affecting  the  ante- 
rior part  of  the  finger,  and  seated  in  the  synovial 
sheath  of  its  flexor  tendon,  the  inflamed  mem- 
brane is  closely  bound  down  by  a  dense  and 
unyielding  fibrous  layer :  hence  not  only  death 
of  the  contained  tendon  may  be  produced,  but 
even  extension  of  the  disease  to  the  bone  itself. 
Such  are  the  morbid  changes  usually  met 
with  in  the  contents  of  inflamed  buisae;  but  if 
the  disease  have  been  of  long  standing,  changes 
scarcely  less  remarkable  are  produced  in  the 
structure  of  the  bursa  itself.  Instead  of  the 
delicate  synovial  membrane  we  have  above 
described,  it  is  frequently  found  converted  into 
a  firm  gristly  substance,  sometimes  half  an 
inch  in  thickness.  In  such  cases  no  tact,  how- 
ever delicate  and  experienced,  could,  previously 
to  operation,  have  detected  the  presence  of 
matter. 

Monro  seems  to  regard,  in  certain  cases  at 
least,  the  communication  above  alluded  to  be- 
tween certain  bursae  and  the  neighbouring  joints 
as  the  result  of  rupture  or  of  friction :  he  even 
considers  it  remarkable  that  in  such  instances 
neither  lameness  nor  pain  had  been  complained 
of  during  the  lifetime  of  the  individual.  It  ap- 
pears to  us,  however,  much  more  probable  that 
in  those  instances  the  synovial  membrane  of  the 
joint  and  that  of  the  bursa  have  been  ab  initio 
but  different  parts  of  one  and  the  same  structure ; 
at  least,  in  our  dissections  of  the  subcrureus 
bursa  in  young  subjects,  we  have  more  than 
once  observed  it  communicating  freely  with 
the  joint. 

For  Bibliography,  see  that  of  SYNOVIAL  MEM- 
BRANE. 

(John  E.  Brenan.) 

CARNIVORA  (euro,  carnis,  and  voro,)  an 
interesting  and  highly  important  group  of  the 
mammifera,  constituting  the  typical  order  of 
that  great  division  of  the  class  which  feed 
upon  animal  aliment.  Whether  the  present 
group  can  with  propriety  be  considered  as  en- 
titled by  its  organization  to  the  ordinal  rank 
which  we  have  assigned  to  it  above,  or  whether 
it  does  not  rather  form  a  subdivision  of  a  great 
order,  answering  nearly  to  the  Carnassiers  of 
Cuvier,  is  a  question  which,  as  it  is  variously 
viewed  by  different  naturalists,  may  be  safely 
left  undecided  in  a  work  like  the  present,  in 
which  structure  rather  than  arrangement  is  the 
principal  object  of  research,  and  in  which  the 
nomenclature  of  a  system  is  of  little  importance, 


compared  with  the  developement  of  anatomical 
and  physiological  truth.  The  Carnassiers  of 
Cuvier  (excluding  the  Marsuplata,  which  may 
unhesitatingly  be  considered  as  a  distinct 
order,)  includes  a  natural  and  tolerably  well 
defined  assemblage  of  animals,  to  which  the 
term  ZOOPHAGA  may  with  propriety  be  applied 
as  the  classical  equivalent  to  the  French  phrase 
of  that  distinguished  zoologist;  but  however 
the  stricter  rules  of  zoological  arrangement  may 
render  it  difficult  to  divide  this  group  into  the 
three  orders  of  CHEIROPTERA,  INSECTIVORA, 
and  CARNIVORA,  it  has  appeared  to  the 
author  of  this  essay  as  more  convenient  on 
the  present  occasion  to  assign  that  designation 
to  each  of  these  divisions,  and  to  make  the 
structure  of  each  the  subject  of  a  separate 
article. 

The  characters  of  the  Carnivora  as  distinct 
from  the  rest  of  the  digitate  animals  possessing 
the  three  distinct  classes  of  teeth,  (which,  be- 
sides the  other  Zoophaga.,  include  the  Quadru- 
mana  and  the  Marsupiata,)  are  such  as  point 
them  out  as  especially  formed  for  the  pursuit 
and  destruction  of  vertebrate  animals.  They 
possess  in  the  upper  and  in  the  lower  jaw  six 
incisive  teeth,  a  large,  strong,  and  pointed  ca- 
nine tooth  on  each  side,  and  molar  teeth  which 
partake  in  a  greater  or  less  degree  of  the  charac- 
ters distinctive  of  the  class,  according  to  the 
habits  of  the  different  genera.  These  molars  con- 
sist of  three  distinct  kinds:  the  anterior,  which 
immediately  follow  the  canine,  are  more  or  less 
pointed,  and  are  termed  false  molars ;  the  next 
class,  formed  especially  for  cutting  in  pieces 
the  flesh  on  which  the  animals  feed,  are  termed 
by  M.  Frederick  Cuvier  Carnassiers;  and  the 
posterior  are  tuberculated.  The  proportion 
which  these  different  classes  of  teeth  bear  to 
each  other  in  number  or  developement,  accords 
with  the  degree  of  the  carnivorous  propensity 
in  the  animal. 

In  agreement  with  these  characters  of  the 
teeth,  the  feet  are  digitate,  the  toes  furnished 
with  claws,  which  in  some  are  retractile ;  the 
stomach  is  simple,  the  intestines  are  short,  and 
the  ccDcum  is  either  very  small  or  altogether 
wanting. 

The  animals  of  this  order  differ  in  the  form 
and  position  of  the  posterior  feet ;  in  some, 
hence  termed  plantigrade,  the  whole  foot  rests 
on  the  ground ;  in  others,  called  digitigrade, 
the  toes  only  touch  the  ground,  the  heel  being 
considerably  raised.  Of  the  former  structure 
the  bears  exhibit  the  type,  and  the  cats  of  the 
latter.  A  third  and  most  remarkable  form  of 
the  extremities  is  shown  in  the  Seal  tribe,  in 
which  the  anterior  as  well  as  the  posterior  feet 
are  formed  for  swimming,  being  spread  into  fin- 
like  paddles. 

The  families  of  which  this  order  is  com- 
posed are  perhaps  as  follow : — 
\ .  URSID^E,  typical  genus  Ursus,  bear. 

2.  MUSTELID^;,     do.          Mustela,  marten. 

3.  CANID-&,  do.  Cam's,  dog,  wolf. 

4.  FELID^;,  do.          Felis.  cat. 

5.  PHOCID.E,          do.          Phoca,  seal. 

Of  these  families  the  FELID^  constitute  the 
type  of  the  order,  possessing  the  carnivorous 


CARNIVORA. 


471 


propensity  and  structure  in  a  higher  degree 
than  any  of  the  others. 

Skeleton. — The  structure  of  the  skeleton  in 
the  cat  tribe  exhibits,  in  the  greatest  imaginable 
degree,  all  the  requisites  of  fleetness,  activity, 
and  power,  for  the  purpose  of  pursuing,  sur- 
prising, overpowering,  and  tearing  the  living 


prey  on  which,  in  a  state  of  nature,  they 
wholly  subsist.  In  the  less  typical  forms  we 
find  these  attributes  possessed  to  a  modified 
extent,  but  still  admirably  adapted  to  their 
respective  habits. 

As  an  example  of  the  typical  structure,  the 
skeleton  of  the  lion  (Jig.  189)  shews,  in  the 


Fig.  189. 


configuration  of  the  bones,  in  their  articulation, 
and  in  the  developement  of  the  different  points 
of  muscular  attachment,  such  a  combination  of 
lightness  of  form  with  vast  power,  as  must 
strike  every  one  as  being  exactly  equivalent  to 
the  natural  requirements  of  the  animal.  The 
spine  is  flexile,  yet  of  great  strength,  and  the 
extent  and  robustness  of  the  lumbar  portion  of 
the  vertebral  column  seem  at  once  adapted  for  the 
exercise  of  that  flexibility,  and  for  the  location 
of  powerful  muscles.  The  ribs  are  narrow 
and  far  asunder ;  the  limbs  long,  powerful,  and 
so  constructed  as  to  afford  the  greatest  facility 
and  extent  of  motion,  an  object  which  is 
greatly  promoted  by  placing  the  point  of  rest 

Fig. 


at  the  extremity  of  the  toes ;  the  whole  of  the 
feet,  excepting  that  part,  being  thus  made  sub- 
servient to  the  object  in  question.  The  cra- 
nium is  broad  and  short,  and  fitted  for  the 
exercise  of  almost  incalculable  force  in  holding 
and  tearing  their  food. 

In  the  weasel  tribe  the  legs  are  shorter,  the 
vertebral  column  elongated  and  in  the  highest 
degree  slender  and  flexible,  the  lumbar  region 
being  as  long  even  as  the  dorsal,  a  structure 
by  which  they  are  enabled  to  creep  with  almost 
a  serpentine  motion  in  quest  of  the  small  and 
sometimes  subterraneous  animals  on  which 
they  subsist. 

In  the  bear  tribe  (fig.  WO)  there  is  a  still 

190. 


472 


CARNIVORA. 


greater  aberration  from  the  type,  in  the  planti- 
grade form  of  the  foot,  by  which  the  animal  is 
enabled  to  walk  with  that  solidity  and  firmness 
which  the  less  degree  of  mobility  in  the  rest 
of  the  skeleton  renders  necessary,  or  to  climb 
trees,  or  dig  the  ground,  in  pursuit  of  the 


various  food  from  which  the  different  genera  of 
this  family  derive  their  nutriment.  The  small 
extent  of  the  lumbar  portion  of  the  spine  com- 
pared with  the  dorsal  which  we  find  in  some 
of  this  tribe,  is  equally  characteristic. 

In  the  Phocidae  or  Seals,  (jig.  191  j,  on  the 


Fig.  191, 


other  hand,  the  most 
remarkable  deviation 
from  the  typical  struc- 
ture is  seen  in  the  adaptation  of 
the  limbs  to  the  aquatic  residence 
and  habits  of  the  animals.  The 
posterior  members  are  extended 
backwards  in  a  horizontal  direc- 
tion, forming  two  broad  fins,  by 
which  they  swim  with  great  facility 
and  strength.  The  anterior  feet  are 
similarly  constructed, but  they  serve 
also  in  some  measure  for  progres- 
sion on  land,  though  to  a  limited 
extent.  The  cranium  is  thin  and 
round,  and  the  teeth,  sharp  and 
many-pointed,  are  formed  for  seiz- 
ing, holding,  and  tearing  fish,  the  activity  of 
whose  motions,  no  less  than  their  scaly  surface 
and  even,  rounded  form,  render  such  a  structure 
absolutely  necessary. 

The  cranium. — The  peculiarities   by  which 
the  cranium  of  this  order  is  distinguished  have 
reference,  not  to  the  form  and  developement  of 
the  brain  only,  but  particularly  to  the  character 
of  the  food,  and  the  consequent  necessity  of 
peculiar  powers  of  mastication,  and   of  the 
other  acts  preparatory  to  the  function  of  diges- 
tion.    We  shall  find,  therefore,  not  only  that 
the  general  form  of  the  skull  in  the  whole  of 
the  Carnivora  is  diffe- 
rent from  those  of  every 
other  group,  but  that  the 
families    composing    it 
differ  in  miror  points  of 
structure,  w:tn  the  same 
relation  to  aliment  and 
habits.    The  cranium  in 
this  order  then  is  cha- 
racterized,  when   com- 
pared with  that  of  most 
other  orders,  especially 
those    which    feed    on 
grain  or  other  substances 
requiring  long  and  la- 
borious  trituration,   by 
great  shortening  of  the 


bones  of  the  face.     This  is  particularly  con- 
spicuous  in  the  cats,   (fig.  192,)    the  seals, 

Fig.  192. 


(Jig.  193,)  and  even  the  hyenas,  but  is  less 
Fig.  193.  * 


so  in  the  bears  (fig.  194)  and  dogs. 
Fig.  194. 


The 


CARNIVORA. 


473 


posterior  aspect  is  generally  small,  directed 
backwards,  and  separated  by  a  strong  occipital 
crest  from  the  anterior  parts  of  the  skull.  From 
this,  in  many  instances,  a  strong,  elevated,  me- 
dian crest  passes  forwards,  which  is  remarkably 
short  in  the  lion,  the  white  bear,  the  hyena, 
the  badger,  and  many  others.  It  is  remarkable 
that  in  many  of  the  Phocidse  this  crest  does  not 
exist,  whilst  in  other  species  it  attains  a  con- 
siderable size.  The  orbit  and  the  immense 
temporal  fossa  are  confounded  in  one  great 
excavation ;  the  zygomatic  arch  is  perfect  and 
of  considerable  size.  The  anterior  opening  of 
the  nares  is  large,  and  directed  forwards,  ex- 
cepting in  certain  seals,  in  which  it  is  placed 
almost  vertically,  for  the  obvious  purpose  of 
facilitating  its  exposure  to  the  atmosphere  when 
these  animals  come  to  the  surface  to  breathe. 

A  remarkable  peculiarity  exists  in  this  order, 
in  the  existence  of  a  bony  process  arising  from 
the  internal  surface  of  the  occipital  and  parietal 
bones,  and  separating  the  lobes  of  the  cerebrum 
from  the  cerebellum.  This  process,  of  mode- 
rate size  in  the  dogs,  is  much  larger  in  the  seals, 
and  still  more  developed  in  the  cats.  In  the 
dogs  it  is  considerable  from  before  backwards, 
but  small  from  side  to  side;  it  is  formed  by 
the  parietal  and  the  squamous  portion  of  the 
occipital.  In  the  seals  the  parietal  bone  is  not 
concerned  in  its  formation  ;  in  the  cats,  on  the 
contrary,  it  entirely  arises  from  this  bone,  not 
being  at  all  connected  with  the  occipital.  The 
object  of  this  bony  tentorium  is  obviously  to 
support  the  different  portions  of  the  brain,  and 
prevent  their  pressing  upon  each  other  during 
the  sudden  and  violent  movements  of  the  ani- 
mal, when  springing  upon  its  prey  or  leaping 
with  great  violence. 

With  regard  to  the  substance  of  the  bones  of 
the  cranium  in  this  order,  although  it  may  be 
observed  generally  that  they  are  of  a  medium 
degree  of  thickness  and  solidity,  there  are  re- 
markable exceptions  in  some  of  the  seals,  in 
which  they  exhibit  an  extreme  degree  of  tenuity, 
the  object  of  which,  in  reference  to  the  medium 
in  which  the  seals  reside,  and  the  necessity  of 
often  rising  to  the  surface  to  breathe,  is  suffici- 
ently obvious.  In  the  cats  and  other  genera, 
where  extraordinary  and  sudden  exertion  is 
frequently  necessary,  the  bones  altogether  are 
found  to  be  remarkably  compact  and  solid. 

A  few  details  of  the  structure  of  the  indivi- 
dual bones  composing  the  cranium  will  be 
necessary,  in  order  to  shew  how  admirably 
every  portion  is  made  to  bear  upon  the  general 
objects  of  the  whole  organization. 

The  frontal  bones,  (fg.  192,  193,  194,  e,) 
which,  as  in  most  other  instances,  are  separate, 
have  a  considerable  developement  of  the  zygo- 
matic or  external  angular  process,  especially  in 
those  whose  habits  are  preeminently  carnivorous, 
as  in  the  cats,  the  mustelidae,  &c.  In  the  ichneu- 
mons it  even  extends  so  far  as  to  meet  the  orbi- 
tary  process  of  the  malar  bone,  and  thus  form 
a  complete  orbitar  circle  ;  the  cats  exhibit  an 
approach  to  such  a  formation,  but  in  the  other 
tribes  it  is  less  and  less  marked,  and  in  the  seals 
there  is  scarcely  the  vestige  of  this  process  to 
be  perceived. 


T\\e  parietal  bones  (f)  are  of  a  quadrate  form ; 
they  are  early  united  in  the  mustelae,  the  cats,  the 
hyenas,  and  the  bears ;  in  the  dogs  and  in  the 
seals,  &cc.  they  remain  more  durably  separated. 
The  interparietal  bone,  as  it  is  called,  (a  large 
os  triquetrum,)  which  is  found  in  many  ani- 
mals, particularly  during  the  young  state,  is 
considerable  in  the  dogs,  in  which  it  remains 
permanently  distinct  from  the  parietal  and  oc- 
cipital. Its  form  in  these  is  that  of  an  elon- 
gated triangle,  which  extends  forwards,  sepa- 
rating the  two  parietal  bones  for  more  than  half 
their  length.  In  this  instance  it  proceeds  from 
a  single  point  of  ossification,  whilst  in  many 
of  the  rodentia  it  arises  from  two  centres  of 
developement.  The  crest  which  is  formed 
along  the  median  line  of  the  cranium,  at  the 
junction  of  the  parietal  bones,  and  which  forms 
a  continuation  forwards  from  the  ridge  of  the 
occipital,  is  greatly  developed  in  the  older  cats 
and  others.  The  lion  and  tiger,  the  wolf  and 
the  bear,  the  badger  and  many  others,  exhibit 
it  in  an  extraordinary  degree.  Its  object  is 
evidently  to  afford  a  strong  and  extended  sur- 
face of  attachment  to  the  powerful  temporal 
muscles,  which  are  required  to  be  enormously 
developed  for  the  purpose  of  cutting  and  tearing 
in  pieces  the  hard  tendinous  portions  of  the 
animal's  prey. 

The  temporal  bone  (g)  is  divided,  as  in  the 
other  mammalia,  into  a  cranial  or  squamous, 
and  a  petrous  or  acoustic  bone.  The  former 
constitutes  the  posterior  and  superior  portion 
of  the  zygomatic  arch,  and  beneath  the  root  of 
this  process  is  situated  the  articular  cavity  for 
the  reception  of  the  condyle  of  the  lower  jaw. 
Its  transverse  form,  and  the  depth  of  its  ante- 
rior and  posterior  boundaries,  afford  a  strong 
and  secure  hold  of  the  condyle,  which,  whilst 
it  thus  moves  freely  within  its  limited  sphere 
of  action,  is  restricted  from  any  other  than 
a  simple  hinge-like  motion.  This  circum- 
stance adds  greatly  to  the  power  of  this  parti- 
cular kind  of  mastication.  The  squamous 
portion  is  but  small,  and  is  externally  more  or 
less  convex.  The  acoustic  portion  is  greatly 
developed  in  the  cats,  and  still  more  so  in  the 
seals,  a  circumstance  which  will  be  further 
alluded  to  hereafter. 

The  occipital  bone  varies  much  in  the  car- 
nivora.  In  the  seals  the  superior  or  squamous 
portion  is  large,  obtusely  triangular,  and  much 
flattened,  being  in  many  species  devoid  of  the 
strong  occipital  ridge  which  is  so  prominent  a 
feature  in  all  the  other  families  of  the  order. 
In  the  cats  this  process  is  very  prominent  and 
strong,  forming  a  solid  attachment  for  those 
powerful  muscles  which  are  necessary  for  the 
forcible  and  even  violent  raising  of  the  head  in 
tearing  the  prey  to  pieces.  It  is  also  strongly 
marked  in  most  of  the  Ursidte,  particularly  in 
the  white  bear,  the  badger,  the  coati,  &c. 
The  inferior  portion,  answering  to  the  cuneiform 
process,  is  in  the  seals  remarkably  broad  and 
thin,  much  more  so  than  in  any  other  of  the 
mammifera;  and  in  this  part  there  is  in  some 
species  of  that  family  an  oval  hole  of  consi- 
derable size,  placed  near  the  inferior  margin  of 
the  foramen  magnum.  This  exists  only  in  cer- 


474 


CARNIVORA. 


tain  species,  In  Ph.  vitulina  for  instance,  and  ap- 
pears to  harmonize  with  the  tendency  to  scanty 
deposition  of  bony  matter,  which  characterizes 
the  whole  cranium  in  this  family.  The  con- 
dyles  in  these  animals  are  also  very  much 
larger  than  in  the  other  carnivora. 

The  sphenoid  bone  has  nothing  very  remark- 
able in  its  structure,  excepting  the  greater 
developement  of  its  alae  in  these  than  in  most 
others  of  the  mammalia,  and  the  small  com- 
pressed triangular  form  of  the  pterygoid  pro- 
cesses which  in  the  cats  are  long  and  hooked 
backwards. 

The  superior  maxillary  bone  consists  of  the 
true  or  posterior  maxillary  ( c)  and  the  intermax- 
illary (a)  portions.  For  the  sake  of  clearness 
they  may  be  described  as  distinct  bones.  The 
body  of  the  maxillary  bone  extends  very  high  up 
in  the  cats,  and  is  remarkably  strong  and  compact. 
In  the  seals  it  is  encroached  upon  by  the  nasal 
opening,  so  as  to  leave  only  a  narrow  neck  be- 
tween that  opening  and  the  orbit.  The  infra- 
orbitar  foramen  is  remarkably  large  in  the  cats 
and  in  the  seals,  in  which  animals  the  long  elastic 
setaceous  whiskers  are  so  useful  as  feelers,  and 
are  supplied  with  large  filaments  of  the  infra-or- 
bitary  branch  of  the  fifth  pair  of  nerves.  The 
length  of  the  body  of  this  bone  depends  on 
the  number  and  nature  of  the  teeth  which  are 
imbedded  in  it,  and  is  shorter  in  proportion  to 
the  predominance  of  the  strictly  carnivorous 
appetite.  The  canine  teeth  and  the  molares 
are  those  which  occupy  this  bone,  the  incisores 
being  placed  in  the  intermaxillary;  and  in  the 
cats  the  body  of  the  bone  is  remarkably  short, 
being  occupied  only  by  four  molar  teeth,  the 
first  of  which  is  small  and  rudimentary,  as 
well  as  the  posterior  one,  which  is  small  and 
tubercular ;  the  two  middle  ones  are  formed  for 
cutting  asunder  the  flesh,  and  are  exceedingly 
strong.  In  the  bears  the  teeth  assume  more  of  a 
tubercular form,and  are,  infact,  adapted  for  mas- 
ticating vegetable  substances  as  well  as  animal 
matters;  the  jaw-bone  is,  therefore,  much  longer 
than  in  the  cats.  In  the  dogs,  which  hold  an 
intermediate  place  in  this  respect,  the  molar 
teeth  are  six  in  number,  and  the  two  posterior 
ones  are  more  or  less  tubercular.  The  anterior 
part  of  the  jaw  is  enlarged  and  rounded  for 
the  location  of  the  large  and  powerful  canine 
teeth.  In  the  Walrus  (Jig,  195,J  the  anterior 
part  of  this  bone  is  greatly  enlarged  for  the 
enormous  canine  teeth,  which  form  powerful 
weapons,  with  which  the  animal  strikes  directly 
down  with  immense  force. 

The  intermaxillary  bones  contain  each  three 
small  incisor  teeth  :  these  in  the  cats  are 
very  small,  excepting  the  external  one,  which 
is  somewhat  larger  than  the  others.  In  the 
seals  they  are  pointed.  These  bones  are  con- 
siderably smaller  in  the  carnivora  than  in  most 
other  orders. 

The  nasal  bones  (b)  are  smaller  in  this  order 
than  in  many  others.  In  the  cats  they  are 
rather  broad  anteriorly,  but  short;  they  are 
longer  in  the  dogs  and  bears,  agreeably  to  the 
greater  length  of  the  face  generally.  In  the 
seals  they  are  much  shortened,  in  order  to  allow 
of  the  great  expansion,  in  an  upward  direction, 


Fig.  195. 


of  the  nasal  aperture,  by 
which,  when  in  the  water, 
they  more  readily  raise 
their  nostrils  to  the  atmo- 
sphere for  the  purpose  of 
breathing. 

The  malar  bone  (h)  per- 
forms a  very  important 
office  in  the  carnivorous 
group,  as  the  zygoma  re- 
quires to  be  very  exten- 
sively developed  for  the 
protection  of  the  enormous  masses  of  mus- 
cle which  are  needed  in  tearing  the  food  of 
these  animals,  as  well  as  for  the  attachment  of 
the  masseter.  The  zygomatic  arch  in  this  order 
is  convex  upwards  as  well  as  curved  outwards, 
by  which  form  a  great  increase  of  strength  is 
acquired  in  the  direction  of  the  muscular 
force. 

The  lacrymal  bone  is  said  to  be  wanting  in 
the  seals.  I  believe  I  have  seen  a  trace  of  its 
existence  in  a  rather  young  cranium  of  Phoca 
vitulina.  The  remarkable  vacancy  which  oc- 
curs in  some  of  this  tribe  in  the  orbito-temporal 
fossa,  between  the  frontal,  the  maxillary,  and 
the  sphenoid  bones,  has  been  supposed  by 
Meckel  to  indicate  the  place  which  the  lacry- 
mal bone  should  occupy;  but  as  this  hiatus 
does  not  exist  in  several  species,  in  which  the 
absence  of  this  bone  is  equally  evident,  this 
supposition  is  probably  not  correct. 

The  inferior  maxillary  bone  (i)  follows  of 
course  the  general  structure  of  the  superior. 
It  is  remarkably  short  in  the  typical  forms  of 
the  carnivora,  and  more  elongated  in  the  others, 
particularly  in  the  bears.  Indeed  this  bone, 
like  the  upper  jaw,  is  shortened  exactly  in  pro- 
portion to  the  carnivorous  propensity  of  the 
animal.  The  ascending  plate  is  also  remarkably 
developed,  and  offers  a  surface  of  great  extent 
for  the  insertion  of  the  elevators  of  the  lower 
jaw. 

The  character  of  the  vertebral  column  in 
the  Carnivora  offers  some  interesting  varieties 
of  form,  depending  principally  on  the  degree 
of  exertion,  of  activity,  or  of  flexibility  re- 
quired by  the  habits  of  the  different  genera. 
The  strength  and  size  of  the  two  first  cervical 
vertebrse,  the  atlas  and  dentata  or  axis,  have 
already  been  alluded  to.  The  first  is  exceed- 
ingly broad  and  robust,  with  strong  transverse 
processes;  the  second  is  long,  with  an  enormous 
spinous  process.  The  remainder  of  the  cervi- 
cal vertebra  are  generally  rather  elongated  in 
most  of  the  genera,  but  in  the  seals  they  are  short 
and  but  little  developed.  In  general,  also,  the 
spinous  processes  are  considerable,  and  either 


CARNIVORA. 


475 


perpendicular  or  directed  rather  forwards,  par- 
ticularly in  the  cats,  the  coatis,  the  badger,  and 
some  others.  In  the  dogs  there  are  also  small 
inferior  spinous  processes.  The  dorsal  region 
varies  much  in  its  relative  proportions  with  the 
lumbar  region  and  with  the  size  of  the  animal ; 
a  point  which  will  be  more  particularly  alluded 
to  presently.  The  spinous  processes  are  very 
strong  and  strait,  and  directed  backwards. 
The  number  of  the  dorsal  vertebra,  and,  con- 
sequently, of  the  ribs,  varies  in  the  different 
genera  of  the  order,  from  thirteen,  which  is  the 
most  common  number,  to  sixteen,  of  which 
we  have  an  example  in  the  Glutton  (Gulo 
articus). 

The  lumbar  vertebra  are  remarkably  strong  in 
almost  all  the  Carnivora,  though  less  so  than  in 
some  other  orders.  The  spinous  processes  are 
long  and  directed  forwards,  particularly  in  the 
cats  and  dogs.  The  transverse  processes  are 
also  very  large  and  strong ;  but  the  most  im- 
portant circumstance  connected  with  the  cha- 
racter of  these  vertebrae  is  the  relative  propor- 
tions which  exist  between  them  and  the  dorsal 
in  different  species,  not  so  much  with  regard 
to  number,  as  to  the  proportional  extent  of  the 
two  regions.  Tn  respect  even  to  number,  the 
variations  of  the  lumbar  vertebrae  are  not  in- 
considerable :  thus,  the  Ratel  and  the  Hyena 
have  only  four,  whilst  the  cats  and  many  others 
have  seven.  But  we  find  that  in  those  species 
which,  from  their  habits,  require  great  power 
of  springing,  of  rapid  running,  or  of  great 
flexibility  of  motion,  the  relative  extent  of  the 
lumbar  region  is  increased  in  proportion.  Thus, 
whilst  in  the  Hyena  the  lumbar  region  bears 
to  the  dorsal  only  the  proportional  length  of 
four  and  a  half  to  fourteen,  and  in  the  Ratel  of 
three  to  eight  and  a  half;  in  the  Lion  we  find 
it  as  fifteen  to  eighteen,  and  in  the  Panther,  the 
Wild  Cat  and  the  Civet,  the  extent  of  the  two 
regions  is  almost  exactly  equal.  This  is  a  con- 
sideration of  great  importance,  not  in  the 
Carnivora  only,  but  in  the  Ruminantia  and 
other  orders,  where  the  different  groups  are 
found  to  vary  much  in  their  powers  of  spring- 
ing and  their  general  activity :  for  the  propor- 
tion of  the  lumbar  to  the  dorsal  regions  will 
invariably  be  found  in  exact  accordance  with 
the  extent  of  those  powers. 

The  Sacrum  is  composed  of  several  vertebrae, 
as  in  most  other  mammifera ;  in  the  present 
order  there  are  generally  three  or  four,  though 
in  the  Brown  Bear  there  are  six  (Cuvier  says 
five),  and  in  the  White  Bear  seven ;  in  the 
Coati  there  is  but  one,  and  in  the  Hyena  only 
two.  The  spinous  processes  of  the  Sacrum 
are  more  developed  in  this  order  than  in  many 
others.  Cuvier  observes  that,  in  those  animals 
which,  from  their  habits,  occasionally  rise  upon 
their  hinder  legs  and  hold  themselves  upright, 
the  Sacrum  is  broader  than  in  others  of  the 
same  order,  and  he  instances  the  Brown  Bear 
in  the  present  order  as  an  example. 

The  tail,  consisting  of  the  coccygeal  vertebra, 
varies  excessively  amongst  the  Carnivora,  and 
this  in  many  cases  in  the  same  family,  and 
with  but  little  obvious  relation  to  the  habits  of 
the  species.  As  a  general  rule  it  may  be  ob- 


served that  the  most  active,  and  those  which 
possess  the  most  flexible  spinal  column,  have 
the  greatest  number  of  caudal  vertebrae.  Thus, 
while  the  Brown  Bear  has  only  about  six,  the 
Lion  has  twenty-three,  and  the  Panther  twenty- 
four. 

In  many  of  the  Carnivora  which  have  long 
tails,  the  spinous  processes  are  generally  di- 
rected from  before  backwards,  but  are  always 
very  small,  and  exist  only  on  the  few  anterior 
vertebrae  of  the  tail.  The  middle  and  posterior 
coccygeal  vertebra  are  therefore  more  deve- 
loped in  length  and  become  almost  cylindrical, 
excepting  that  they  are  thicker  at  each  extre- 
mity. As  in  other  orders,  the  anterior  portion 
only  of  the  tail  conveys  the  spinal  marrow, 
the  posterior  being  impervious.  The  most  im- 
perfect developement  of  this  portion  of  the 
vertebral  column  is  found  in  the  Seals,  in 
which  generally  it  is  only  the  first  vertebra 
which  possesses  even  a  trace  of  spinous  and 
transverse  processes,  the  remainder  being  al- 
most cylindrical,  without  even  any  enlargement 
at  each  extremity. 

The  ribs  correspond  in  number  with  the 
dorsal  vertebrae.  Their  curvature  varies  con- 
siderably both  as  regards  the  different  portions 
in  the  same  species  and  the  general  form  in 
different  groups.  In  many  of  the  mammifera 
the  difference  in  this  respect  between  the  an- 
terior and  middle  regions  of  the  thorax  is  very 
Striking;  this,  however,  is  generally  not  so 
much  so  in  the  present  order,  in  which,  as  a 
general  rule,  the  anterior  ribs  are  not  less 
arched  than  the  others.  The  anterior  ones, 
however,  are  very  much  smaller  and  shorter 
than  the  middle  and  posterior.  The  relative 
number  of  true  and  false  ribs  would,  a  priori, 
appear  to  have  some  relation  to  the  degree  of 
rapidity  or  of  flexibility  in  the  animal's  move- 
ments; and  hence  that  those  which  leap  or 
swim  would  require  greater  mobility  of  the 
thorax,  and  consequently  a  greater  proportion 
of  false  ribs.  Now,  although  this  is  strikingly 
the  case  with  regard  to  some  of  the  cetacea, 
which  have  only  from  one  to  five  fixed  ribs, 
and  from  ten  to  seventeen  false,  yet  no  such 
rule  is  observable  in  the  present  order;  the 
Seal  and  the  Lion  having  even  a  less  propor- 
tion of  moveable  ribs  than  the  Bear  and  the 
Glutton. 

The  sternum  in  the  Carnivora  does  not  vary 
greatly  in  breadth  in  its  different  portions.  It 
is  much  more  developed  longitudinally  in  these 
animals  than  in  most  others,  and  is  scarcely 
broader  than  it  is  deep.  The  anterior  piece  of 
this  bone  in  the  Seals  is  remarkably  long,  and 
is  also  moveable. 

The  shoulder,  composed  of  the  same  ele- 
ments as  in  the  other  mammifera,  varies,  how- 
ever, considerably  in  the  degree  of  develope- 
ment of  the  bones  of  which  it  is  formed.  The 
scapula  is  depressed  and  remarkably  broad 
from  the  anterior  to  the  posterior  margin,  and 
in  some  cases — as  in  the  Badger  especially, 
and  in  some  degree  in  the  Bear — it  assumes 
almost  a  quadrate  form.  The  spine  of  this 
bone,  which  in  the  Seal  is  very  small,  is  of 
great  size  and  strength  in  the  bear  tribe,  par- 


476 


CARNIVORA. 


ticularly  in  the  Badger.  The  acromion  is  small 
and  slight  in  all  the  true  Carnivora,  but  in 
those  of  the  Insectivora  which  have  true  cla- 
vicles, it  is  long  and  robust.  The  coracoid 
process  is  generally  present,  but  is  wanting  in 
the  seals.  The  clavicle  in  the  whole  of  this 
order  is  very  slender,  and  must  be  considered 
as  merely  rudimentary.  In  the  Hyena  and  the 
Dog  it  is  extremely  small ;  larger  in  the  Mus- 
telida,  and  still  larger  in  the  Cats.  It  is  not 
attached  to  the  sternum  or  to  the  scapula,  but 
suspended,  as  it  were,  between  these  two  bones, 
generally  occupying  not  much  more  than  half 
the  space  between  them. 

The  humerus  is  in  general  rather  slender, 
long  and  nearly  cylindrical  when  compared 
with  that  of  the  Pachydermata,  Ruminantia, 
and  some  others.  It  is  somewhat  arched,  and 
the  great  tuberosity  is  very  much  developed ; 
this  bone  is  short  and  broad,  the  superior  two- 
thirds  being  widened  from  before  backwards, 
and  the  lower  third  from  side  to  side. 

The  fore-arm  is  here,  as  in  the  other  orders, 
composed  of  the  radius  and  the  ulna.  The 
latter  bone  is  generally  placed  immediately 
behind  the  former,  and  they  have  but  little 
motion  one  on  the  other,  excepting  in  the  bear 
tribe,  whose  habits  require  more  freedom  of 
movement  in  the  anterior  extremity.  That 
tendency  to  the  expansion  of  the  members  into 
instruments  fitted  for  swimming,  which  is  so 
obvious  in  the  Seals,  is  found  to  obtain  in  the 
two  bones  in  question,  which  in  this  family  are 
short,  flattened,  and  very  broad. 

The  carpus  in  this  order  offers  a  few  pecu- 
liarities which  may  be  slightly  glanced  at.  The 
os  scapho'ides  and  the  os  similunare  form  but 
one  bone,  which  is  of  considerable  size.  The 
os  pisiforme  is  much  elongated,  forming  a  little 
spur  or  heel  to  the  anterior  feet,  a  peculiarity, 
however,  which  is  wanting  in  the  seals.  The 
os  trapezium  is  very  small  in  the  Hyena,  in 
which  the  thumb  is  but  rudimentary. 

The  metacarpal  bones  in  the  digitigrade  car- 
nivora  are  much  larger  than  in  the  plantigrade. 
In  the  latter  the  shortness  of  these  bones,  with 
the  comparative  length  of  the  phalanges,  gives 
somewhat  of  a  plantigrade  character  even  to 
the  fore-feet,  although  the  metacarpal  bones  do 
not  actually  rest  upon  the  ground  :  whilst  in 
the  digitigrade  families,  and  especially  in  the 
cats,  the  metacarpals  being  much  produced, 
and  the  phalanges  very  short,  the  part  which 
rests  upon  the  ground  is  greatly  abbreviated. 

The  phalanges  offer  some  very  interesting 
points  of  structure,  particularly  in  the  Felida:,  in 
which  the  terminal  phalanx  is  retractile,  or,  on 
the  other  hand,  can  be  thrust  out  and  rendered 
the  basis  of  a  most  formidable  weapon.  This 
character  of  the  retractile  claw  is,  in  its 
full  developement,  peculiar  to  the  family  just 
named ;  and  the  Lion  may  be  selected  as 
offering,  from  its  great  size,  the  most  conve- 
nient opportunity  for  its  examination.  In  all 
the  Carnivora  the  claw  is  fixed  on  the  extremity 
of  the  last  phalanx  (fig.  196,  a,  a),  the  hooked 
form  of  this  part  of  the  bone  being  an  accurate 
model  of  the  interior  of  the  claw,  and  the  base 
of  the  claw  is  secured  within  a  thin  lamina  or 


hood  of  bone  which  covers  it  on  the  sides  and 
above.  In  the  animal  just  named  this  is  par- 
ticularly strong  and  large.  It  is  considerable 
also  in  the  Badger,  but  less  so  in  the  Bears, 
the  Dogs,  the  Hyenas,  &c.,  and  in  the  Civets 
it  is  very  small.  The  penultimate  phalanx  is 
of  a  peculiar  form.  Its  transverse  section 
would  be  triangular,  two  of  the  sides  being 
lateral,  and  the  third  inferior.  On  the  inner 
face  or  side,  there  is  a  hollowing  or  twist  of  the 
bone,  which  leaves  an  oblique  excavation  in 
the  middle.  It  is  by  the  inferior  portion  of  the 
last  phalanx  that  it  is  articulated  to  the  penul- 
timate, and  beneath  the  joint  a  process  of  the 
last  phalanx  extends  downwards,  for  the  at- 
tachment of  the  muscles  by  which  the  toes  are 
flexed,  and  consequently  the  claw  protruded. 
When  the  claw  is  retracted  or  in  a  state  of  rest, 
the  last  phalanx  is  brought  upwards  and  thrown 
completely  hack  on  the  inner  side  of  the  se- 
cond phalanx,  being  partly  lodged  in  the  lateral 
hollow  before  described.  This  is  the  condition 
of  repose,  and  the  last  phalanx  is  held  in  this 
situation  by  the  elasticity  of  the  capsular  liga- 
ment, and  particularly  by  two  lateral  ligaments 
which  arise  from  the  second  phalanx. 

The  posterior  extremity. — The  pelvis  in  the 
Carnivora  is  shorter  than  in  many  other  orders, 
and  the  ossa  ilii  particularly  are  flattened  and 
rather  broad.  Their  internal  surface  also  is  not 
turned  forwards  as  in  most  other  orders,  but 
for  the  most  part  directed  towards  the  spine, 
so  that  the  ventral  aspects  of  these  two  bones 
face  each  other.  In  most  of  the  seals  the  ilia  are 
short  and  small,  compared  with  the  other  bones 
of  the  pelvis.  The  posterior  or  descending 
branch  of  the  ischium,  and  the  anterior  portion 
of  the  pubis  are,  in  particular,  much  elongated 
in  this  family. 

The  femur  is  strait,  cylindrical,  and  mode- 
rately long  in  most  of  the  Carnivora.  In  the 
Seals  it  is,  however,  extremely  short,  as  may  be 
observed  in  fig.  191.  In  this  tribe  this  bone 
does  not  assume  the  direct  backward  direction 
of  the  leg-bones,  but  stands  outwards  and 
downwards,  by  which  a  great  extent  of  motion 
is  obtained  for  the  hinder  paddles. 

The  tibia  and  fibula*  (fig.  196,  /,  m; 
fig.  197,  »,  k;  fi.g.  198,  /, m;)  are  detached  in 
most  of  the  Carnivora;  but  in  the  Dog  the 
fibula  is  attached  to  the  back  part  of  the  tibia. 
In  the  Phocidte  these  bones  are  long,  flattened, 
directed  backwards,  and  the  tibia  has  a  double 
curvature.  The  tarsus  consists  of  the  same 
bones  in  the  Carnivora  as  in  Man,  (fig.  196, 
/,gA^,j%-197,e,/,gA/g.l98,/,g,M,; 
the  os  calcis  has  a  very  long  and  robust  tube- 
rosity both  in  the  digitigrade  (fig'  196,  /c)  and 
plantigrade  (fig.  197,  A)  forms.  In  the  former 
there  is  also  on  the  inferior  surface  a  small 
tubercle  which  is  wanting  in  the  others. 


*  The  figures  representing  the  hinder  foot  are 
selected  for  the  purpose  of  shewing  the  three  prin- 
cipal types  of  progression  in  the  Carnivora.  Fig. 
196,  that  of  the  Lion,  exhibits  the  digitigrade, 
Jig.  197,  that  of  the  polar  bear,  the  plantigrade ; 
and  fig.  198,  that  of  the  seal  ( Phoca  vitulina),  the 
natatory. 


CARNIVORA. 


477 


Fig.  196. 


Fig.  197. 


The  metatarsal  bones  (Jig.  196, 107,  198,  d) 
are  generally  five.  In  the  cats  and  the  dogs, 
indeed,  the  inner  one  is  merely  rudimentary, 
a  defect  which  is  perfectly  consonant  with  the 
absence  of  a  posterior  thumb  in  these  two 
genera.  Those  of  the  seal  tribe  are  remark- 
ably long  and  slender.  The  first  is  the  longest, 
the  fifth  the  next,  then  the  second,  the  fourth, 
and  the  middle  one  which  is  the  shortest. 

The  toes  consist  of  three  phalanges  (Jig.  196, 
197,  198,  a,  b,  c,)  and  in  most  genera  there  are 
five  toes;  the  bears  and  other  plantigrades 
having  the  inner  toe  or  thumb  in  the  same 
range  as  the  others ;  in  the  mustelida  it  is  a 
little  smaller,  and  in  the  cats  and  dogs  it  is 
wholly  wanting.  The  toes  in  the  seal  tribe  are 
developed  to  considerable  length,  and  being 
much  extended,  and  covered  with  an  entire 
skin  which  extends  from  one  to  the  other,  a 
very  perfect  finlike  paddle  is  thus  furnished. 

The  types,  then,  of  the  three  different  varie- 
ties of  progression  are  here  distinctly  shewn. 
In  the  foot  of  the  bear  (Jig.  197)  we  find  that 
every  thing  in  its  formation  is  made  subser- 
vient to  the  action  of  walking;  the  heel,  the 
tarsal  and  the  metatarsal  bones,  and  the  pha- 
langes all  rest  upon  the  ground,  and  these 
bones  are  elongated  for  that  purpose.  In  the 
Lion  (Jig.  196)  the  last  phalanges  only  rest  on 
the  ground,  the  heel  being  drawn  upwards,  and 
the  whole  of  the  foot,  excepting  that  small 
portion  which  is  applied  to  the  ground,  is  thus 
made  an  additional  lever  for  the  increase  of  the 
animal's  powers  of  leaping  and  bounding  in 
its  course.  In  this  form  the  limb  consists  of 
three  joints  (the  pelvis  being  the  fixed  point) 
moveable  in  alternately  different  directions, 
capable  of  being  all  approximated  to  each 
other,  and  then  suddenly  and  simultaneously 


extended  with  prodigious  force.  In  the  third 
type,  that  of  the  Seal  (fg.  198),  the  bones  are 
all  much  flattened,  and,  excepting  the  foot, 
greatly  shortened;  the  foot  itself  being  de- 
veloped both  longitudinally  and  laterally  into  a 
finlike  expansion. 

The  Muscular  System. — The  general  cha- 
racter of  the  muscles  in  the  Carnivora  is  that 
of  combined  power  and  irritability.  The  ele 
vators  of  the  lower  jaw,  the  masseters  and  the 
temporals,  are  enormously  large,  for  the  pur- 
pose of  cutting  and  tearing  the  flesh  and  the 
harder  portions  of  their  food.  The  muscles 
of  the  face  also,  those  of  the  lips,  of  the  nose, 
of  the  eyelids,  and  of  the  ears,  are  all  of  them 
greatly  developed  and  capable  of  the  most 
extensive  and  powerful  motion.  A  moment's 
reflexion  upon  the  habits  of  these  animals,  and 
particularly  on  those  of  the  cats,  will  shew  the 
necessity  of  enormous  power  in  the  muscles 
which  raise  the  head  upon  the  spine.  A  Lion, 
it  is  said,  can  kill  a  moderate-sized  bullock,  throw 
it  on  his  back  by  a  toss  of  the  head,  and  trot 
off  with  it  to  his  hiding-place.  All  the  muscles, 
therefore,  which  arise  from  the  vertebrae  of  the 
neck  and  are  inserted  into  the  projecting  ridge 
of  the  occipital  bone,  are  of  prodigious  strength. 
The  same  remark  holds  good  of  all  the  muscles 
of  the  limbs,  particularly  those  of  the  anterior 
extremity,  but  which  do  not  require  a  par- 
ticular description  or  demonstration.  The  mus- 
cles of  the  tail,  which  are  for  the  most  part 
similar  in  this  order  to  those  in  the  tailed  Qua- 
drumana  and  Ruminantia,  will  be  described 
in  the  articles  devoted  to  the  anatomy  of  those 
animals. 

The  digestive  organs. — The  structure  which 
has  been  already  detailed  in  the  skeleton  of  the 
Carnivora,  and  alluded  to  in  their  muscular 


478 


CARNIVORA. 


system,  will  be  found  altogether  subservient  to 
the  office  of  procuring  that  peculiar  kind  of 
food  to  which  these  animals  are  restricted,  and 
the  modifications  of  that  structure  which  have 
been  described  as  appertaining  to  different 
types  of  form  in  the  order,  are  equally  con- 
sonant with  the  modified  nature  of  their  ali- 
ment. Thus,  whilst  the  powerful  yet  active 
and  flexible  movements  of  the  typical  Carni- 
vora  are  adapted  only  to  the  pursuit  and  de- 
struction of  living  prey,  the  more  sluggish  habits 
of  most  of  the  bear  tribe,  their  peculiar  mode 
of  progression,  and  the  modified  structure  of 
the  skull,  the  teeth,  and  the  limbs,  are  all 
equally  applicable  to  the  mixed  nature  of  their 
food ;  and  the  third  principal  type — that  of  the 
amphibious  carnivordj  the  Seals — exhibits  an 
arrangement  of  these  organs  not  less  admirably 
fitted  for  the  pursuit  and  capture  of  their 
aquatic  and  scaly  prey.  The  digestive  organs 
of  each  of  these  prominent  groups  are  not  less 
perfectly  formed  for  the  digestion  of  their  vari- 
ous food,  than  the  organs  which  have  already 
been  described  are  for  its  capture.  The  teeth 
have  already  been  slightly  alluded  to,  but  they 
deserve  a  more  particular  description.  In  the 
cats,  the  character  of  the  teeth  is  typically  car- 
nivorous. The  incisores  are  very  small,  as 
indeed  they  are  throughout  the  whole  order. 
The  canine  teeth  are,  on  the  contrary,  pre- 
eminently strong,  long  and  sharp,  and  are 
evidently  adapted  for  seizing  and  holding  their 
prey  and  afterwards  tearing  in  pieces  the  flesh 
and  other  soft  parts  of  the  animals.  These 
teeth  are  conical  and  very  slightly  curved, 
a  form  which,  united  with  their  sharpness  and 
strength,  is  the  best  that  can  be  imagined  for 
effecting  this  object.  The  cheek  teeth,  instead 
of  having  flat  grinding  surfaces,  have,  for  the 
most  part,  only  cutting  edges ;  and  those  of 
the  lower  jaw  shut  within  the  upper,  passing 
them  so  closely  as  to  form  an  accurate  instru- 
ment either  for  shearing  off  pieces  from  the 
flesh  or  for  cutting  into  morsels  the  portions 
which  have  been  torn  by  the  canine  teeth. 
On  each  of  them  are  sharp  triangular  processes 
which  much  facilitate  the  entrance  of  the  tooth 
into  the  flesh.  The  range  of  these  teeth  is 
short,  as  is  also  the  whole  jaw,  by  which  great 
power  is  gained  in  this  particular  direction. 
The  articulation  of  the  lower  jaw  is  also  cir- 
cumscribed to  a  perpendicular  motion,  the  only 
one  which  the  structure  of  the  teeth  would 
permit.  The  strong  muscles  of  the  lips  also 
enable  the  animal  to  raise  them  out  of  the  way 
of  injury  during  this  process.  The  animals  of 
the  bear  tribe,  on  the  other  hand,  have  an 
elongated  jaw,  canine  teeth,  although  very  large 
and  strong,  yet  less  so  than  in  the  cats,  and 
molares,  the  surfaces  of  which,  instead  of  being 
raised  into  cutting  edges,  are  depressed,  tuber- 
cular, and  require  a  certain  degree  of  lateral 
motion  in  the  jaw  to  bring  them  into  action. 
In  the  seals  a  very  different  structure  of  the 
teeth  is  observed.  The  canines  are  not  par- 
ticularly large  and  prominent ;  and  the  molares, 
neither  adapted  on  the  one  hand  for  shearing 
nor  on  the  other  for  grinding  their  food,  either 
of  which  actions  would  be  unavailable  in  their 


particular  case,  are  numerous  and  furnished 
with  several  angular  points,  which  are  fitted 
for  holding  the  slippery,  scaly  surface  of  fish, 
and  equally  so  for  crushing  them  before  they 
are  swallowed.  The  teeth  of  the  Walruses, 
however,  are  very  different  from  those  of  many 
other  of  the  Phocida.  The  tusks  (fig.  195) 
which  are  enormous  canine  teeth  of  the  upper 
jaw,  are  directed  downwards,  and  constitute 
formidable  weapons  of  defence,  and  the  mo- 
lares are  formed  rather  for  grinding  than  for 
merely  holding  their  prey. 

The  food  then  being  thus  variously  prepared 
by  the  different  groups  of  this  order,  passes 
into  the  stomach  more  or  less  masticated. 
The  salivary  glands  in  the  meantime  have  been 
performing  their  important  office.  The  vari- 
ations in  form  and  situation  of  these  glands 
are  slight  and  unimportant.  The  submaxillary 
glands  are  generally  as  large  as  the  parotid, 
which  in  the  dogs  and  cats  are  of  a  crescentic 
form,  embracing  by  their  concave  margin  the 
conch  of  the  ear ;  and  in  the  dogs  the  inferior 
portion  is  distinct  from  the  rest.  The  sub- 
lingual  are  wanting  in  the  cats. 

The  stomach  in  all  the  animals  of  this  order 
is  perfectly  simple,  and  its  interior  smooth, 
with  the  exception  of  that  of  the  Seal,  which 
has  a  villous  coat.  In  the  cats  (that  of  the 
Lion  is  shewn  aijig.  199)  it  is  elongated,  and 

Fig.  199. 


the  two  openings  are  placed  nearly  at  each  end : 
there  is  a  small  pouch  however  at  the  cardiac 
extremity.  In  the  Wild  Cat  it  is  somewhat 

Epriform,  the  pyloric  portion  being,  as  in  the 
ion,  doubled  upon  the  other  part;  and  in  the 
Lynx  the  cardiac  and  pyloric  openings  are 
more  distant  than  perhaps  in  any  other  species. 
In  the  other  genera  the  form  varies  a  little. 
It  is  nearly  globular  in  the  Racoon ;  that  of  the 
Hyena  is  large  and  short.  In  the  seals  it  is 
elongated  from  before  backwards,  the  pyloric 
portion  being  turned  forwards  upon  the  other ; 
at  the  bend  there  is  a  pouch,  at  which  point  a 
glandular  layer  is  found  between  the  internal 
coat  and  the  cellular. 

The  intestinal  canal  is  in  these  animals  re- 
markably short,  particularly  in  the  cats ;  in  the 
Lion  and  in  the  Wild  Cat  the  whole  alimentary 
canal  is  but  three  times  the  length  of  the  body. 
In  the  Seal  it  is  much  longer.  The  distinction 
between  the  small  and  large  intestines  varies 
considerably  In  the  Badger  this  distinction 
can  scarcely  be  said  to  exist :  in  the  Lion  it  is 
considerable,  and  still  more  so  in  the  seals  and 


CARNIVORA. 


479 


Fig.  200. 


others.  The  caecum  exists,  but  is  very  small 
and  short  in  the  cats  :  (Jig.  200  shews  that  of 
the  Lion.)  In 
the  dogs  it  is  spi- 
ral. The  whole 
canal  is  almost 
destitute  of  vul- 
vul<£  conniventeSj 
nor  is  the  large 
intestine  tucked 
up  into  sacs  as 
in  other  orders. 
The  mustelidtc 
generally  have  no  cacum  nor  valvula  coli. 

A  short  comparative  view  of  the  structure 
thus  hastily  sketched,  with  that  of  the  digestive 
system  in  the  typical  herbivora,  the  ruminant 
animals,  will  not  be  uninteresting.  The  Car- 
nivora  feeding  on  aliment  which  requires  but 
little  elaboration  to  convert  it  into  nourish- 
ment, the  whole  process  of  digestion  appears  to 
be  as  rapid  as  possible,  and  we  find  that  every 
part  of  the  organisation  is  admirably  adapted 
to  this  object.  The  strength  of  the  jaws,  the 
form  of  the  teeth,  the  structure  of  the  maxillary 
articulation  are  all  contrived  for  preparing  the 
food  by  simple  division.  The  stomach  is  sim- 
ple and  almost  straight,  the  intestines  short,  and 
without  any  structure  to  retard  the  passage  of 
the  food.  In  the  ruminantia,  on  the  contrary, 
the  jaws  are  much  elongated,  the  molar  teeth 
flat  and  formed  for  affording  the  greatest  pos- 
sible extent  of  triturating  surface,  the  maxillary 
joint  allowing  of  the  most  extensive  lateral  mo- 
tion, the  stomach  complicated,  and  a  second 
and  more  complete  mastication  is  performed 
after  the  food  has  been  long  macerated  in  the 
paunch.  The  intestines  are  exceedingly  long, 
(in  the  ram  twenty-eight  times  the  length  of 
the  body,)  very  large,  and  tucked  up  into  folds 
and  sacs  throughout  their  whole  length.  Here 
every  thing  is  arranged  for  the  thorough  com- 
minution and  maceration  of  the  food,  and  for 
the  greatest  possible  retardation  of  its  passage 
through  the  body,  as  well  as  for  an  immense 
extent  of  absorbing  surface  for  the  extraction 
of  every  particle  of  nutritious  matter. 

The  liver  in  the  Carnivora  is  deeply  divided 
into  lobes,  which  vary  in  number  in  different 
species.  Thus  in  many  of  the  plantigrades 
there  are  five,  as  the  brown  bear,  the  coati, 
and  the  racoon ;  in  the  otter  also,  and  in  the 
martens  and  generally  in  the  dogs  there  are  the 
same  number.  The  Badger  has  but  four.  The 
cats  generally  have  from  five  to  seven,  though 
that  of  the  jaguar  has  but  four,  and  that  of  the 
lynx  eight.  This  numerical  variation  appears, 
therefore,  to  have  no  reference  to  any  physio- 
logical law,  nor  to  any  peculiarity  of  habit. 

The  hepatic  ducts  offer  some  peculiarities 
worthy  of  notice.  In  the  cats  there  are  always 
several,  which  correspond  with  the  different 
lobes  of  the  liver.  Before  the  ductus  corn- 
munis  opens  into  the  duodenum  after  passing 
the  muscular  coat  of  the  intestine,  it  forms  a 
considerable  enlargement,  divided  by  an  in- 
ternal contraction  into  two  cavities,  into  the 
first  of  which  the  pancreatic  duct  opens.  In 
the  dog  the  ductus  communis  enters  the  intes- 


tine with  one  of  the  pancreatic  ducts.  In  the 
otter,  the  common  duct  forms  a  second  reser- 
voir near  the  duodenum. 

The  gall-bladder  exists  in  all  the  Carnivora. 
It  varies  in  some  measure  in  form,  being  py- 
riform  in  most,  elongated  and  almost  cylin- 
drical in  many  of  the  mustelida,  and  rounded 
in  the  bear,  the  racoon,  and  some  others.  It 
is  of  great  size  in  several  of  the  plantigrades. 

The  pancreas  is  similar  in  its  general  struc- 
ture to  that  of  the  other  mammifera.  It  varies 
in  form,  but  not  in  any  way  that  can  be  sup- 
posed to  give  it  a  peculiarity  in  function.  The 
pancreatic  ducts  vary  also  in  number  and  in 
the  situation  at  which  they  open  into  the  liver. 
In  some  instances,  as  in  the  cats,  the  pan- 
creatic and  common  biliary  ducts  are  united 
and  enter  the  intestine  at  one  orifice,  though 
this  circumstance  is  not  uniform  in  the  genus, 
nor  even  in  all  individuals  of  the  same  species. 
As  a  general  rule  in  this  order  the  ducts  of 
these  two  important  glands  terminate  together. 

The  spleen  requires  also  to  be  merely  glanced 
at,  as  its  characters  and  situation  do  not  ma- 
terially differ  from  those  in  the  other  orders 
of  the  class.  It  is  generally  elongated  and 
narrow,  and  either  flattened  or  somewhat  pris- 
matic. 

The  chyliferous  system. — The  chyle  in  the 
Carnivora  has  always  been  remarked  for  its 
whiteness  and  opacity,  a  circumstance  which 
greatly  facilitates  the  tracing  the  course  of  the 
lacteals  in  this  order,  and  which  in  fact  gave 
rise  to  their  discoveiy  in  these  animals  before 
they  were  seen  in  man.  The  mesenteric  glands 
are  united  either  into  one  large  mass  only, 
as  in  most  examples  of  the  order,  into  two  as 
in  mustela,  or  the  larger  substance  is  associated 
with  several  smaller  ones,  as  in  the  cats,  the 
otter,  the  seal,:  and  some  others.  This  glan- 
dular mass  has  been  termed  Pancreas  Asellii, 
from  its  having  been  erroneously  mistaken  for 
a  pancreas  by  that  anatomist. 

The  thoracic  duct  in  the  dog  is  double, 
and  in  the  Sea  Otter  it  has  been  found  by  Sir 
Everard  Home  that  two  ducts  go  from  the 
receptaculum  chyli  to  form  this  duct,  which  in 
its  course  sometimes  divides  into  two,  three,  or 
four,  again  uniting  at  intervals. 

Organs  of  circulation. —  The  heart  and  blood- 
vessels offer  but  few  peculiarities  in  this  order 
worthy  of  particular  notice.  The  heart  varies 
but  little  in  form ;  its  parietes  are  remarkably 
strong  in  the  larger  cats,  in  the  lion  particularly. 
The  general  structure  of  this  viscus  does  not 
differ  materially  from  that  of  the  other  mam- 
mifera. There  is,  however,  a  question  of  some 
interest  which  has  been  often  debated  ;  this  is, 
whether  the  foramen  ovule  and  the  ductus 
arteriosus  remain  pervious  in  the  seals  and  the 
otter.  The  testimony  of  Cuvier  and  of  Blumen- 
bach  goes  to  prove  that,  at  least  in  many  in- 
stances, these  openings  are  closed.  Cuvier 
states  it  to  have  been  so  in  a  seal,  and  Blumen- 
bach  says  that  this  is  its  general  condition. 
On  the  other  hand  Sir  Everard  Home  has 
given  two  examples  in  which  \heforamen  ovule 
remained  pervious  in  the  sea  otter;  Blumen- 
bach  also  states  that  he  possesses  the  heart  of 


480 


CARNIVORA. 


an  adult  seal,  in  which  both  these  channels  of 
communication  remained  open  ;  and  the  writer 
of  this  article  dissected  a  seal  some  years  since 
which  was  nearly  full  grown,  in  which  the 
foramen  ovule  was  so  open  as  to  allow  the 
tip  of  the  little  finger  to  enter,  and  the  ductus 
arteriosus  would  admit  with  ease  the  bulb  of  a 
common  probe. 

Upon  the  whole  then  it  appears  that,  al- 
though the  pervious  condition  of  these  chan- 
nels cannot  bi  considered  as  general  in  the 
adult  state  of  these  diving  animals,  as  has 
sometimes  been  supposed,  it  must  be  allowed 
that  this  exception  is  far  more  frequent  in  them 
than  in  any  other  mammiferous  animals,  and 
that,  as  a  general  rule,  these  holes  remain  open 
later  in  such  animals  than  in  others.  There  is, 
however,  in  the  otters  and  in  the  seals,  a  con- 
siderable dilatable  enlargement  observed  in  the 
inferior  cava,  which  serves  doubtless  as  a  re- 
servoir to  retain  part  of  the  returning  blood 
during  submersion,  until  the  animal  rises  again 
to  breathe. 

Organs  of  respiration.  —  The  lungs  are  di- 
vided into  lobes  varying  but  little  in  number 
in  the  terrestrial  families  of  the  order.  These 
all  have  four  lobes  to  the  right  lung,  and  either 
two  or  three  to  the  left.  The  seals  have  the 
right  lung  divided  into  two  lobes,  and  the  left 
undivided. 

The  cartilaginous  portions  of  the  rings  of 
which  the  trachea  is  composed  vary  in  the 
proportions  which  these  bear  to  the  whole 
circle;  in  the  genus  Mustela  and  some  others, 
the  cartilage  forms  about  two-thirds  of  the 
circle;  in  the  bear,  the  coati,  and  the  cats, 
about  three-fourths  ;  and  in  the  ichneumon  as 
much  as  four-fifths. 

The  nervous  system.  —  On  viewing  the  dif- 
ferent orders  of  mammifera  in  the  ascending 
series,  the  brain  of  the  Carnivora  (Jig.  201 
being  an  upper  and  a  lateral  view  of  that  of  the 
Lion)  will  be  found  to  exhibit  a  higher  degree 


i.  201. 


of  developement  than  exists  either  in  the 
cetacea,  in  any  of  the  forms  of  the  herbivora, 
or  in  the  marsupiata ;  the  hemispheres  have 
here  a  well-marked  superiority  of  develope- 
ment over  the  cerebellum  and  tubercula  quadri- 
gemina.  On  the  other  hand  the  brain  of  the 
Carnivora  is  less  developed  anteriorly  than  in 
the  Quadrumana,  the  anterior  lobes  being  some- 
what narrowed  and  depressed,  and  the  con- 
volutions, (although  deeper  than  in  the  orders 


just  mentioned,)  instead  of  the  labyrinthine 
duplicatures  which  are  observable  in  the  Qua- 
drumana and  in  man,  are,  generally  speaking, 
longitudinal  in  their  direction,  the  principal 
being  but  two  on  each  side  of  the  median  line, 
crossed  by  a  transverse  anterior  one.  The 
cerebellum  is  almost  wholly  uncovered  as  seen 
from  above,  not  more  than  one-fifth  of  it  lying 
under  the  posterior  edges  of  the  hemispheres. 
The  optic  thalami,  however,  are  concealed  not 
only  from  above  but  even  on  a  lateral  view, 
by  the  hemispheres.  Of  the  tubercula  qua- 
drigemina,  the  posterior  are  the  larger. 

The  eye  possesses  but  few  peculiarities  of 
any  importance.  The  relative  proportions  of 
the  different  humours  are  here  more  nearly 
equalized  than  in  any  order  of  the  mammalia, 
at  least  in  some  of  the  genera,  as  the  following 
comparative  view  will  shew : — 

Aqueous.      Crystalline.     Vitreous. 

P°g A  •••  A  ••*••-;* 

Man fc     .  .  .    £     .  .  .     ft 

Ox     *    ...    fc    ...  J 

The  vitreous  humour,  therefore,  is  much  less 
than  in  either  of  the  other  cases,  and  the  crys- 
talline smaller  in  proportion  than  that  of  man. 
The  crystalline  lens  in  the  Seal  fulfils  the  gene- 
ral law  which  gives  to  it  a  degree  of  sphericity 
in  relation  with  the  aquatic  habits  of  the 
animal.  Thus  the  crystalline  of  fishes  is  ab- 
solutely spherical,  that  of  the  cetacea  nearly  so, 
and  that  of  the  seal  and  of  the  otter  very  much 
less  flattened  than  in  those  animals  which  re- 
side and  seek  their  food  on  land.  In  the  seal 
also  the  sclerotic  is  considerably  thickened 
anteriorly  and  still  more  dense  at  the  posterior 
part,  whilst  the  middle  zone  is  very  thin  and 
flexible, —  a  structure  which  must  offer  great 
facility  for  the  action  of  the  different  muscles 
which  compress  the  globe,  and  alter  the  rela- 
tive proportion  of  its  diameter  to  its  axis.  The 
form  of  the  pupil  differs  in  different  groups. 
In  the  diurnal  carnivora,  and  even  in  some 
nocturnal,  it  is  permanently  round  ;  but  in  the 
cats  it  is  perpendicular  during  its  contracted 
state,  and  in  a  very  bright  light  it  is  almost 
linear,  but  even  in  these  it  becomes  perfectly 
round  in  the  dark,  and  the  ellipse  which  it 
forms  in  its  contraction  is  more  or  less  length- 
ened or  acute  according  to  the  degree  of  light. 
The  inner  surface  of  the  choroid  is  partially 
lined  with  a  brilliant  greenish  tapetum,  similar 
to  that  which  is  found  in  the  ruminantia,  and 
occupying  nearly  the  same  situation. 

The  lachrymal  gland  exists  throughout  this 
order,  and  the  glandula  Uarderi  is  also  found 
in  its  members  as  well  as  in  the  ruminantiaf 
pachydermata,  and  some  if  not  all  the  ro- 
dentia. 

The  organ  of  hearing  is  developed  to  a  very 
considerable  degree  in  most  of  the  Carnivora. 
The  external  ear  varies  much  in  size  and  form ; 
it  is  moderate  in  the  cats,  small  in  the  bears, 
and  rudimentary  in  the  seals,  but  enormously 
large  in  the  Fennec,  a  species  of  the  family 
CanidfB.  There  is  in  these,  as  well  as  in  many 
other  mammiferous  animals,  especially  the  ro- 
dentia,  a  remarkable  hollow  appendage  to  the 


CARNIVORA. 


481 


true  tympanum,  taking  the  place  of  the  mastoid 
process,  and  probably  performing  the  same 
office  as  the  mastoid  cells.  This,  in  many, 
forms  a  large  rounded  process  beneath  the 
cranium.  In  the  cats  it  is  remarkably  large 
and  globose ;  in  the  bear,  on  the  contrary,  it  is 
not  visible  externally.  The  object  of  this  en- 
larged cavity  is  doubtless  to  give  additional 
volume  to  the  sounds  which  are  brought  to  it, 
a  circumstance  especially  required  by  the  noc- 
turnal habits  of  those  species  in  which  it  is 
most  largely  developed.  The  fenestra  rotunda, 
which  is  covered  by  a  membrane  stretched 
across  it,  is  believed  by  Cuvier  to  be  intended 
for  the  reception  of  the  sounds  produced  by 
the  resonance  of  the  bony  case  just  described  ; 
an  opinion  which  is  perfectly  consonant  with 
that  of  Scarpa,  who  considers  the  hole  in 
question,  with  its  membrane,  as  a  sort  of  se- 
condary tympanum.  The  fenestra  rotunda  is 
the  larger  of  the  two  apertures  of  communi- 
cation with  the  internal  ear  in  the  present  order 
generally ;  in  some  of  the  most  nocturnal,  the 
cats  and  the  civets,  it  is  almost  double  the  size 
of  the  fenestra  ovalis.  The  passage  answering 
to  the  Euslachian  tube  is  remarkably  short  and 
can  scarcely  be  called  tubular;  in  the  cats  and 
civets  it  is  nothing  more  than  a  narrow  cleft  in 
the  suture  which  unites  the  tympanum  to  the 
true  petrous  bone. 

The  organ  of  smell  is  generally  extensive  in 
the  carnivorous  animals,  and  in  addition  to  the 
principal  apparatus  of  this  sense,  the  different 
sinuses  which  augment  the  nasal  cavity,  par- 
ticularly the  frontal,  are  of  considerable  extent, 
especially  in  the  canida.  But  the  most  re- 
markably developed  of  the  surfaces  on  which 
the  pituitary  membrane  is  distributed,  are 
those  of  the  superior  and  inferior  turbinated 
bones.  The  inferior  are  very  complicated  in 
their  convolutions  in  the  dogs,  the  bears,  seve- 
ral of  the  cats,  and  particularly  in  the  otters 
and  the  seals.  This  complication  consists  of 
repeated  and  multifarious  bifurcation  ;  and  the 
ultimate  divisions  of  this  bone,  which  all  as- 
sume a  parallel  direction,  form  a  great  number 
of  channels  which  the  air  traverses  in  the  act 
of  inspiration,  and  which  are  all  covered  by 
the  pituitary  membrane.  The  ethmoidal  cells 
and  the  superior  turbinated  bones  are  likewise 
greatly  developed  in  the  Carnivora,  and  par- 
ticularly in  those  in  which  the  before-men- 
tioned structure  of  the  inferior  turbinated 
bones  is  most  conspicuous — a  remark  which 
also  applies  to  the  numerous  foramina  in  the 
cribriform  plate  of  the  ethmoid. 

In  the  bear,  and  particularly  in  the  coati, 
the  cartilages  of  the  nose  form  a  complete  tube, 
which  is  articulated  moveably  to  the  bony  nos- 
trils. The  same  structure  is  still  more  remark- 
able in  the  mole. 

The  organ  of  taste. — The  structure  of  the 
surface  of  the  tongue  in  the  Felida  is  very 
remarkable  with  regard  to  the  characters  of  the 
various  papillae  with  which  it  is  furnished.  The 
edges  are  everywhere  covered  with  small  soft 
conical  papilla,  as  well  as  with  the  papilla 
petioluta:,  such  as  are  found  in  most  other 

VOL.  I. 


animals.  The  whole  of  the  middle  part  is 
covered  with  papilla  of  two  kinds  very  dif- 
ferent from  each  other,  and  these  two  kinds  are 
arranged  in  alternate  rows  in  a  quincuntial 
order.  Those  of  one  kind  are  soft,  rounded, 
and  appear  to  consist  of  bundles  of  filaments, 
which  are  supposed  by  Cuvier  to  be  the  ulti- 
timate  extremities  of  the  gustatory  nerves, 
though  this  opinion  appears  from  the  recent 
observations  of  Breschet  to  be  very  doubtful* 
The  others  are  conical  and  pointed,  and  each 
of  them  is  covered  by  a  sharp  horny  case 
curved  a  little  backwards.  It  is  these  horny 
spines  which  render  the  tongue  of  the  cats  and 
the  civets  so  exceedingly  rough  as  that  their 
continued  licking  would  soon  abrade  the  hu- 
man skin.  The  tongue  in  all  the  other  Carni- 
vora scarcely  differs  in  its  structure  from  that 
of  the  human  subject. 

Secretions.  —  The  urine.  The  structure  of 
the  kidney  in  some  of  the  Carnivora  is  wor- 
thy of  notice.  Instead  of  being  a  compact 
and  united  mass  as  in  man,  it  is  subdivided 
into  numerous  portions  similar  to  those  of  the 
human  foetus.  In  the  cats  this  division  is 
scarcely  perceptible,  the  surface  being  only  in- 
terrupted by  superficial  fissures  or  sulci.  But 
in  the  bears,  the  otters,  and  the  seals,  the  sepa- 
ration is  so  deep  as  to  resemble  in  some  sort 
a  bunch  of  grapes.  In  the  otter  there  are  only 
ten  of  these  divisions  in  each  kidney ;  in  the 
bear  there  are  about  fifty,  and  in  the  seal  from 
a  hundred  and  twenty  to  a  hundred  and  forty. 
As  this  peculiarity  of  structure  is  found  to 
exist  in  a  still  more  remarkable  degree  in  the 
cetacea,  Cuvier  has  suggested  whether  it  may 
be  connected  with  the  occasional  longer  or 
shorter  suspension  of  respiration,  as  it  obtains 
in  the  cetacea,  the  seals,  the  otters,  which 
are  often  submerged,  in  the  bears  which  re- 
main torpid  during  the  winter,  and  in  the 
human  foetus  which  has  never  breathed.  Its 
existence,  however,  in  the  elephant,  the  ox, 
and  many  other  animals  whose  respiration  is 
never  interrupted,  renders  this  explanation, 
as  Cuvier  himself  observes,  extremely  unsatis- 
factory. 

The  existence  of  follicles  producing  a  pecu- 
liar secretion  is  not  an  uncommon  circumstance 
in  several  orders  of  the  mammifera,  as  well  as 
in  many  reptiles.  In  the  Carnivora  these  fol- 
licles are  found  in  almost  all  the  genera,  and 
in  some  attain  to  a  large  size.  They  are  situ- 
ated one  on  each  side  of  the  anus,  and  the 
excretory  duct  opens  near  the  termination  of 
the  rectum.  The  substance  usually  secreted 
by  these  glandular  surfaces  is  strongly  odor- 
ous, and  in  some  cases  intolerably  fetid.  The 
annexed  engraving  (fig-  202)  is  taken  from 
a  specimen  of  Gallictis  vittata,  which  I  dis- 
sected some  time  since,  and  is  selected, 
because  it  has  not  been  before  figured,  and 
because  the  glands  are  of  large  size  and  very 
distinct.  Each  follicle  is  covered  by  a  muscle 
of  no  inconsiderable  strength,  the  object  of 
which  is  to  compress  the  follicle,  and  to 
force  out  the  secretion  through  the  duct.  One 
of  the  follicles  is  represented  covered  by  its 

2  i 


482 


CAROTID  ARTERY. 


Fig.  202. 


muscle;  the  other  has  had  the  muscle  re- 
moved. 

Besides  these  follicles  there  is  in  several 
species  a  pouch,  somewhat  resembling  those 
above  described,  but  differently  situated.  It  is 
always  single,  and  in  the  badger  and  hyena  is 
placed  between  the  anus  and  the  tail ;  in  the 
ichneumon  it  surrounds  the  anus,  and  in  the 
civet  it  is  found  between  the  anus  and  the 
opening  of  the  prepuce  in  the  male,  and  be- 
tween the  anus  and  the  vulva  in  the  female. 
The  secretion  of  this  sac  in  the  latter  animal  is 
well  known  as  a  scent  of  a  most  powerful 
musk-like  odour.  The  sac  opens  by  a  longi- 
tudinal slit,  and  in  the  interior  are  seen  two 
cavities  in  which  the  substance  is  secreted,  and 
which  are  furnished  with  a  muscular  coat  for 
its  expression. 

Generative  system.  —  Male  organs.  The 
structure  of  the  testes  is  similar  to  those  of  the 
other  mammiferous  animals,  but  they  vary  con- 
siderably in  situation.  In  most  of  the  genera, 
as  in  the  bears,  the  cats,  the  martens,  the  hy- 
enas, the  ichneumons,  &c.  they  are  perma- 
nently suspended  in  a  pendulous  scrotum.  In 
the  civets  they  are  enclosed  under  the  skin  of 
the  perineum,  and  in  the  otter  under  that  of  the 
groin.  In  the  seals,  in  which  a  pendulous 
scrotum  would  be  exposed  to  continual  danger 
of  injury  or  destruction,  they  remain  con- 
stantly within  the  abdomen,  being  retained  in 
their  situation  by  a  production  of  the  peri- 
toneum, resembling  the  broad  ligaments  of  the 
uterus. 

The  vesicula  seminales  do  not  exist  in  most 
of  the  Carnivora.  They  are  found  in  the 
coatis,  but  not  in  their  congeners.  The  pros- 
tate, gland,  or  at  least  a  glandular  body  ap- 
parently analogous  to  it,  is  found  throughout 
the  order.  It  varies  in  form  and  exceedingly 
in  size ;  in  the  otter  and  the  other  mustelida  it 
consists  of  a  thin  layer  only,  whilst  in  the  dogs 
and  cats  it  forms  a  large  and  conspicuous  bulb 
around  the  urethra. 

Cowper's  glands  also  are  found  in  many  of 
these  animals,  but  are  wanting  in  the  planti- 
grades, in  the  mustelida,  the  dogs,  and  the 
seals.  In  the  Felidtz  (the  cats  and  the  civets) 


and  still  more  in  the  hyena,  they  are  on  the 
other  hand  of  great  size,  and  the  muscle  which 
envelopes  them  is  of  considerable  thickness. 

The  penis  is  found  to  vary  but  little  in  its 
form  and  direction  in  this  order.  It  is,  in  al- 
most all,  directed  forwards,  and  contained 
within  a  sheath  formed  of  an  extension  of  the 
integuments  of  the  abdomen.  In  the  cats 
the  extremity,  during  its  relaxed  state,  is  turned 
backwards,  and  the  urine  is  consequently 
voided  in  that  direction,  but  during  its  erect 
condition  it  assumes  the  same  position  as  in 
the  other  Carnivora.  Almost  the  whole  of  the 
carnivorous  order  possess  a  bone  of  the  penis, 
of  various  size  and  length.  The  hyena  is  a 
remarkable  exception,  as  in  its  congeners,  the 
dogs,  &c.,  it  is  of  considerable  size.  This  is 
the  case  also  with  the  ursidee  and  the  mustelida ; 
but  in  the  cats  and  the  ichneumon  it  is  small. 
The  anterior  extremity  of  this  bone  is  fixed  in 
the  glans,  and  the  posterior  is  attached  to  the 
corpus  cavernosum.  In  some  genera,  particu- 
larly the  dogs,  the  corpus  spongiosum  under- 
goes a  remarkable  degree  of  tumefaction,  which 
retains  the  two  sexes  in  coitu  for  a  considerable 
time. 

The  female  organs. — The  clitoris  is  found  in 
all  the  Carnivora.  It  is  contained  in  a  sort  of 
pouch  within  the  vulva  in  the  wolf,  and  at 
some  distance  in  front  of  this  part  in  the  civet. 
In  some  of  those  species  in  which  the  penis 
of  the  male  is  furnished  with  a  bone,  the  clitoris 
of  the  female  has  also  a  rudimentary  one. 
This,  however,  is  not  constant.  It  is  not  found 
in  the  dogs  or  civets,  but  exists  in  the  cats,  the 
bears,  and  the  otter. 

The  uterus  is  two-horned,  and  resembles  that 
of  most  other  mammifera. 

The  mammary  glands  are  situated  along  the 
sides  of  the  belly,  and  the  number  of  teats 
varies  greatly,  without  any  general  law  as 
regards  the  affinities  of  the  species.  Most  of 
the  plantigrades  have  six;  but  the  lion  has 
four,  the  cat  eight,  and  the  panther  six ;  the 
bitch,  again,  has  from  eight  to  ten. 

The  placenta  consists,  in  the  cat,  the  dog, 
the  marten,  and  others,  of  a  perfect  zone  sur- 
rounding the  foetus,  and  attached  by  its  whole 
external  surface  to  the  uterus;  in  the  polecat 
it  is  formed  of  two  rounded  masses  connected 
together. 

For  the  BIBLIOGRAPHY,  see  that  of  MAMMALIA. 
(T.  Bell.) 

CAROTID  ARTERY,  (human  anatomy,) 
(arteria  carotis  ;  Gr.  nct^ur^ ;  Fr.  carotide  ; 
Germ,  die  Carotis,  Kopjpulsader ; )  the  great 
artery  which  on  each  side  distributes  blood  to 
the  different  parts  of  the  head.  The  term 
carotid,  derived  from  xapoj,  sopor ,  appears  to 
have  been  first  applied  to  the  arteries  of  the 
head  by  the  ancients  from  a  supposition  that  a 
state  of  drowsiness  or  deep  sleep  depended  on 
compression  or  some  other  affection  of  these 
vessels  exercising  an  influence  over  the  circula- 
tion of  the  blood  in  its  passage  through  them 
to  the  brain  :  in  accordance  with  the  same 


CAROTID  ARTERY. 


483 


opinion  they  have  been  also  called  arterite 
sopor  if/era. 

The  carotid  arteries  consist  of — 1  st,  the  pri- 
mitive carotids,  of  which  the  right  arises  from 
the  arteria  innominata,  while  the  left  comes 
directly  from  the  arch  of  the  aorta ;  2d,  the  ex- 
ternal carotid ;  and,  3d,  the  internal  carotid : 
these  last  two  vessels  on  each  side  being  pro- 
duced by  the  bifurcation  of  the  primitive  ca- 
rotid. 

Both  primitive  carotids  are  of  equal  size 
according  to  Bichat,  Boyer,  and  Cloquet ;  nei- 
ther Meckel  nor  Tiedemann  make  any  remark 
as  to  a  difference  in  their  size,  while,  according 
to  Soemmerring,  the  right  is  one-twenty-fifth 
larger  than  the  left  in  the  majority  of  in- 
stances. 

The  origin  of  the  right  carotid  from  the 
arteria  innominata  is  opposite  the  right  sterno- 
clavicular  articulation.  The  left  carotid  arises 
from  the  transverse  portion  of  the  arch  of  the 
aorta  behind  the  first  bone  of  the  sternum,  on  a 
plane  with  the  centre  of  the  junction  of  the 
cartilages  of  the  first  pair  of  ribs  with  that  bone 
in  front,  and  corresponding  with  the  superior 
edge  of  the  second  thoracic  vertebra  posteriorly ; 
owing  to  this  difference  in  their  origins,  the  left 
primitive  carotid  is  from  one  inch  to  one  inch 
and  a  quarter  longer  than  the  right,  and  is  con- 
tained within  the  thorax  in  the  commencement 
of  its  course;  it  may  therefore  be  divided  into 
a  thoracic  and  a  cervical  portion. 

The  thoracic  portion  of  the  left  primitive 
carotid,  by  which  I  mean  that  portion  which 
extends  from  the  origin  of  the  artery  to  a  point 
on  a  level  with  the  sterno-clavicular  articulation, 
has  the  following  relations  : — anteriorly  it  is 
covered  by  the  left  vena  innominata,  the  remains 
of  the  thymus  gland,  some  loose  cellular  tissue, 
and  occasionally  a  few  lymphatic  glands;  in 
front  of  these  the  origins  of  the  sterno-thyroid 
and  sterno-hyoid  muscles  separate  it  from  the 
sternum  ;  posteriorly  it  rests  on  the  oesophagus, 
left  recurrent  nerve,  the  origin  of  the  left  sub- 
clavian  artery,  the  left  par  vagum,  the  thoracic 
duct,  and  some  loose  cellular  tissue,  in  addition 
to  which  the  longus  colli  is  interposed  between 
it  and  the  front  of  the  spinal  column ;  on  its 
right  side  it  is  bounded  by  the  trachea,  and  on 
its  left  by  the  phrenic  nerve  and  the  mediasti- 
nal  portion  of  the  left  pleura,  which  gives  a 
loose  covering  to  a  small  portion  of  its  surface, 
against  which  the  internal  side  of  the  apex  of 
the  left  lung  is  applied. 

The  right  primitive  carotid  and  the  cervical 
portion  of  the  left  are  of  equal  length,  and  have 
similar  relations :  at  first,  in  the  lower  part  of 
the  neck  these  vessels  of  opposite  sides  are  only 
separated  by  the  breadth  of  the  trachea :  as 
they  ascend,  however,  they  diverge  from  each 
other,  and  are  separated  by  the  larynx  and 
thyroid  body  :  in  their  ascent  they  seem  to  pass 
backwards,  owing  to  the  prominence  of  the 
larynx  forwards,  but  in  reality  they  cannot  re- 
cede, as  they  are  closely  applied  to  the  front  of 
the  spinal  column ;  they  are  not  contorted  in 
their  course,  nor  do  they  furnish  any  branch 
until  they  arrive  as  high  as  the  superior  margin 


of  the  larynx,  where  each  bifurcates  by  dividing 
into  the  external  and  the  internal  carotids. 

Relations  of  the  trunk  of  the  Primitive 
Carotid. — Anteriorly  the  primitive  carotid  is 
covered  by  the  three  following  layers  of  mus- 
cles from  the  sterno-clavicular  articulation  to 
the  level  of  the  cricoid  cartilage ;  1st,  the  pla- 
tysma  myoides,  beneath  which  lies  the  superfi- 
cial layer  of  the  cervical  fascia;  2d,  the  sternal 
portion  of  the  sterno-cleido-mastoid ;  and  3d, 
by  the  sterno-hyoid,  sterno-thyroid,  and  the 
omo-hyoid,  which  latter  muscle  crosses  the 
sheath  of  the  artery,  having  its  internal  edge 
connected  with  the  outer  edge  of  the  sterno- 
thyroid  by  a  dense  fascia,  a  part  of  the  deep 
layer  of  the  cervical  fascia,  which  is  firmly  con- 
nected to  the  posterior  margin  of  the  clavicle 
inferiorly :  between  the  lower  part  of  the  sterno- 
mastoid  and  the  front  of  the  artery  there  is  an 
interval  of  about  an  inch  on  the  left  side,  and 
something  less  on  the  right,  in  consequence  of 
the  origin  of  the  right  carotid  being  so  much 
more  anterior  on  that  side;  this  interval  is 
filled  by  cellular  and  adipose  tissue,  some  large 
veins,  one  or  more  of  the  sub-clavicular  branches 
of  the  cervical  plexus,  and  occasionally  a  few 
lymphatic  glands;  at  the  level  of  the  cricoid 
cartilage  the  sterno-mastoid  passes  backward, 
and  the  omo-hyoid  coming  from  beneath,  it 
passes  forwards  to  its  insertion  into  the  os 
hyoides.  Above  the  crossing  of  these  two 
muscles  the  carotid  has  no  muscular  covering, 
except  the  platysma,  from  which  it  is  separated 
by  cellular  membrane,  several  veins  from  the 
thyroid  body  and  larynx,  and  some  lymphatic 
glands ;  the  nervus  descendens  noni  also  lies  in 
front  of  the  primitive  carotid  at  its  upper  por- 
tion, being  found  sometimes  within,  sometimes 
outside,  and  occasionally  embedded  in  the  sub- 
stance of  the  wall  of  its  sheath;  the  thyroid 
body  also  generally  overlaps  the  carotid  by  its 
outer  edge. 

Posteriorly  the  carotid  is  bounded  by  the 
longus  colli  and  rectus  capitis  anticus  major, 
which  separate  it  from  the  anterior  surface  of 
the  spinal  column;  the  cervical  cord  of  the 
sympathetic  nerve  and  its  superior  and  middle 
cardiac  branches  are  closely  connected  to  the 
posterior  part  of  its  sheath;  the  vertebral  artery 
and  vein  are  behind  it  at  its  lower  part ;  and 
higher  up  it  crosses  the  inferior  thyroid  artery 
at  a  point  corresponding  to  that  at  which  it  is 
covered  in  front  by  the  omo-hyoideus ;  some- 
times the  inferior  thyroid  crosses  over  the  ca- 
rotid :  the  arteria  cervical  is  ascendens  often  lies 
behind  the  carotid  towards  the  upper  part  of 
the  neck ;  moreover,  the  recurrent  nerve  on  the 
right  side,  in  its  course  from  behind  the  sub- 
clavian  artery  to  the  side  of  the  trachea,  passes 
behind  the  origin  of  the  right  carotid.  From 
the  relations  of  the  primitive  carotid  posteriorly, 
it  is  evident  that  it  can  be  most  effectually 
compressed  against  the  front  of  the  spinal  co- 
lumn, but  to  continue  such  pressure  for  any 
length  of  time  would  obviously  be  followed  by 
injurious  effects,  from  the  lesion  to  which  the 
nerves  behind  the  sheath  of  the  vessel  would 
be  thus  subjected. 

2  i  2 


484 


CAROTID  ARTERY. 


Externally  the  carotid  artery  is  bounded  by 
the  internal  jugular  vein  and  the  pneu mo-gas- 
tric nerve,  both  of  which  are  contained  within 
its  sheath  ;  the  vein  when  distended  advances 
in  front  of  it  and  partly  conceals  it ;  the  nerve 
lies  in  the  posterior  part  of  the  sheath,  behind 
and  between  the  artery  and  vein,  more  closely 
attached  to  the  latter  vessel ;  on  the  left  side 
the  internal  jugular  vein  lies  closer  to  the  ca- 
rotid, in  front  of  which  it  passes  at  the  lower 
part  of  the  neck  in  its  course  to  the  vena  inno- 
minata; on  the  right  side  the  jugular  vein  is 
separated  from  the  carotid  infenorly  by  a  small 
intervening  space,  principally  occupied  by  cel- 
lular tissue,  in  consequence  of  the  vein  of  this 
side  descending  to  join  the  commencement  of 
the  superior  cava  in  a  perpendicular  course 
further  from  the  mesial  line  than  the  point  at 
which  the  carotid  is  given  off  from  the  arteria 
innominata. 

Internally  the  carotid  is  bounded  by  the 
trachea  at  its  lower  part;  higher  up  by  the 
thyroid  body  and  the  inferior  constrictor  of  the 
pharynx,  by  which  it  is  separated  from  the 
cricoid  and  thyroid  cartilages;  the  recurrent 
nerve  also  lies  on  its  inner  side,  but  separated 
from  it  by  a  quantity  of  loose  cellular  tissue; 
in  addition  to  the  foregoing  relations,  the  left 
carotid  lies  in  contact  with  the  oesophagus. 

The  varieties  to  which  the  origins  of  the 
carotid  arteries  are  subject  are  the  following  : 
1 .  the  right  carotid  sometimes  arises  separately 
from  the  aorta ;  this  variety  occurs  when  there 
are  four  large  trunks  arising  from  the  arch  of 
the  aorta,  of  which  the  right  carotid  is  the  first, 
and  the  right  subclavian  the  last  in  order ;  2. 
sometimes  the  arteria  innominata  gives  origin 
to  the  left  carotid,  in  addition  to  the  right  ca- 
rotid and  right  subclavian,  in  which  case  the 
left  carotid  has  to  cross  in  front  of  the  lower 
part  of  the  trachea  to  enter  upon  its  cervical 
course ;  3.  the  right  and  left  carotids  some- 
times spring  from  a  common  trunk,  which 
arises  from  the  arch  of  the  aorta  between  the 
right  and  left  subclavian  arteries ;  in  this  variety 
as  well  as  in  the  preceding,  the  situation  of  the 
carotids  in  front  of  the  trachea  exposes  them  to 
the  danger  of  being  wounded  in  the  operation 
of  tracheotomy,  in  performing  which  the  sur- 
geon should  always  be  prepared  to  meet  with 
the  existence  of  such  irregularities  of  distribu- 
tion: 4.  the  left  carotid  sometimes  arises  from 
a  left  arteria  innominata,  which  also  gives  off 
the  left  subclavian.  (See  AORTA.) 

The  bifurcation  of  the  primitive  carotid  most 
frequently  occurs  opposite  the  superior  margin 
of  the  thyroid  cartilage,  in  front  of  the  third 
cervical  vertebra;  it  may,  however,  take  place 
above  or  below  that  point.  It  sometimes  bifur- 
cates opposite  the  cornu  of  the  os  hyoides,  or, 
which  rarely  happens,  behind  the  angle  of  the 
lower  jaw;  in  cases  where  the  bifurcation  is 
higher  than  usual,  the  primitive  carotid  often 
furnishes  some  of  the  branches  ordinarily 
arising  from  the  external  carotid.  The  high 
bifurcation  is  an  approximation  to  that  condi- 
tion of  the  carotid  in  which  no  bifurcation 
takes  place,  but  where  the  primitive  carotid, 


after  having  given  all  the  branches  which  the 
external  carotid  usually  supplies,  enters  the 
cranium  and  becomes  the  internal  carotid. 
2.  The  primitive  carotid  sometimes  bifurcates 
lower  down  in  the  neck  than  usual.  I  have 
seen  such  a  bifurcation  occurring  on  both  sides 
in  an  old  female  subject,  as  low  as  the  inferior 
border  of  the  thyroid  body. 

The  bifurcation  of  the  carotid  has  the  same 
relation  to  the  larynx  at  all  periods  of  life :  it 
is  more  distant  from  the  angle  of  the  jaw  in 
the  infant  than  in  the  adult;  the  depth  of  the 
lower  jaw  in  the  former  being  much  less,  owing 
to  the  non-development  of  the  roots  of  the 
teeth  and  alveolar  processes:  in  old  persons 
who  have  lost  their  teeth,  and  whose  alveolar 
processes  have  been  absorbed,  the  jaw  being 
in  the  edentulous  condition,  the  angle  of  the 
jaw  is  carried  forward  and  thus  removed  farther 
from  the  bifurcation  of  the  carotid.  By  de- 
pressing the  head  the  angle  of  the  jaw  is 
brought  nearer  to  the  bifurcation ;  while  the 
distance  between  these  parts  may  be  consi- 
derably increased  by  throwing  the  head  back- 
wards. 

The  bifurcation  of  the  primitive  carotid  gives 
origin  to  the  external  and  internal  carotids; 
the  former  of  these  supplies  the  larynx,  thyroid 
body,  pharynx,  throat,  face,  and  external  parts 
of  the  head ;  the  latter  is  distributed  to  the 
brain  and  the  internal  parts  of  the  organs  of 
hearing  and  vision.  These  two  vessels  he  close 
together  at  their  origins.  The  internal  is  at 
first  more  superficial  and  more  external  in 
situation  than  the  external,  but  becomes  the 
more  deeply  situated  of  the  two  as  they  ascend. 
They  are  nearly  of  equal  size  in  the  adult  when 
the  bifurcation  occurs  at  the  usual  place;  while 
in  the  infant  the  internal  is  larger  than  the 
external. 

THE  EXTERNAL  CAROTID,  (arteria  carotis 
externa,  superficialis  vel  anterior,  Scemm.  fa- 
dale  of  Chaussier,)  extends  from  the  bifurca- 
tion of  the  primitive  carotid  to  the  neck  of  the 
condyle  of  the  lower  jaw,  where  it  terminates 
by  dividing  into  the  superficial  temporal  and 
internal  maxillary  arteries.  In  this  course  it 
describes  a  curve,  the  concavity  of  which  is 
outwards  and  a  little  backwards,  as  it  ascends 
between  the  ear  and  the  ramus  of  the  lower 
jaw.  At  first  it  is  superficial,  merely  covered 
by  the  integuments,  platysma  and  cervical 
fascia;  it  then  ascends  under  the  ninth  or 
hypoglossal  nerve  and  the  posterior  belly  of  the 
digastric  and  stylo-hyoid  muscles,  and  buries 
itself  in  the  substance  of  the  parotid  gland.  In- 
ternally it  rests  at  first  on  the  commencement  of 
the  internal  carotid,  then  over  the  middle  con- 
strictor of  the  pharynx,  the  stylo-pharyngeus 
and  stylo-glossus  muscles,  the  glosso-pharyn- 
geal  nerve  and  the  styloid  process  of  the  tem- 
poral bone ;  the  superior  and  inferior  pharyn- 
geal  nerves  coming  from  the  par  vagum  also 
pass  under  it  in  their  course  to  the  pharyngeal 
plexus.  The  part  of  the  parotid  gland  which 
the  external  carotid  first  enters  is  the  internal 
surface  of  its  lower  extremity,  consequently 
the  whole  thickness  of  the  gland  covers  it  at 


CAROTID  ARTERY. 


485 


that  part;  but  in  passing  through  the  gland 
the  artery  becomes  more  superficial  as  it  ascends 
and  is  covered  only  by  a  very  thin  layer  of  the 
glandular  substance  at  the  place  where  it  ter- 
minates. The  branches  of  the  portio  dura 
forming  theses  anserinus  cross  the  course  of 
the  carotid  in  the  substance  of  the  gland,  being 
superficial  to  it  and  separated  from  it  by  the 
posterior  facial  vein  and  part  of  the  glandular 
substance. 

Branches  of  the  external  carotid* — The  ex- 
ternal carotid  gives  off  eight  principal  branches; 
three  anteriorly,  the  superior  thyroid,  the  lin- 
gual, and  the  labial  or  facial;  two  posteriorly, 
the  occipital  and  posterior  aural;  one  internally, 
the  ascending  pharyngcal ;  and  two  superiorly, 
the  superficial  temporal  and  internal  maxillary, 
besides  several  smaller  branches,  the  number 
and  origins  of  which  are  subject  to  great 
^regularity,  and  which  are  distributed  to  the 
sterno-mastoid  muscle,  the  superior  cervical 
ganglion  of  the  sympathetic  nerve,  the  digastric, 
stylo-hyoid,  stylo-pharyngeus,  and  stylo-glos- 
sus  muscles,  &c.,  to  the  parotid  gland,  the 
external  ear,  and  to  the  integuments. 

ANTERIOR  BRANCHES. — 1st.  The  superior 
thyroid  artery  (A.  thyroidea  superior)  gene- 
rally arises  opposite  the  cornu  of  the  os  hyoides 
a  few  lines  above  the  bifurcation  of  the  primi- 
tive carotid ;  in  some  rare  cases  it  comes  from 
the  trunk  of  the  primitive  carotid :  it  has  been 
also  seen  to  arise  from  the  lingual.  It  takes  a 
tortuous  course  downwards  and  forwards,  and 
passing  under  the  omo-hyoid,  sterno-thyroid, 
and  sterno-hyoid  muscles,  arrives  at  the  supe- 
rior and  external  part  of  the  thyroid  body  to 
which  it  is  chiefly  distributed:  at  first  it  is 
superficial,  being  covered  by  the  integuments, 
platysma,  cervical  fascia,  some  lymphatic  glands 
and  small  veins  coming  from  the  superior  part 
of  the  larynx  to  join  the  internal  jugular ;  it  is 
also  crossed  by  the  branch  of  the  nervus  de- 
scendens  noni  which  is  sent  to  the  superior 
belly  of  the  omo-hyoid  muscle,  and  the  supe- 
rior laryngeal  and  several  filaments  from  the 
sympathetic  nerves  to  the  larynx,  &c.  lie  be- 
neath it.  In  its  course  the  superior  thyroid 
artery,  besides  furnishing  a  variable  number  of 
smaller  branches,  to  the  muscles  and  other 
parts  in  its  vicinity,  generally  gives  off  the 
three  following :  «.  The  hyoidean  branch,  which 
runs  along  the  inferior  border  of  the  os  hyoides 
between  the  hyo-thyroid  muscle  and  the  mem- 
brane of  the  same  name,  to  both  which  it  gives 
branches ;  it  inosculates  with  the  corresponding 
artery  of  the  opposite  side  in  the  mesial  line, 
and  with  the  lingual  by  a  twig  which  passes  up 
on  the  front  of  the  body  of  the  os  hyoides. 
The  hyoidean  branch  is  often  absent,  b.  The 
superficial  branch  passes  downwards  and  out- 
wards over  the  sheath  of  the  carotid  artery  to 
the  sterno-mastoid  muscle,  to  which  and  the 
neighbouring  lymphatic  glands  and  integu- 
ments it  is  finally  distributed,  anastomosing 

*  In  the  arrangement  of  the  branches  of  the 
external  carotid  artery  the  writer  follows  that  of 
Meckel.  See  his  Anatomic  Descriptive,  &c.  trans- 
lated into  French  by  Breschet  and  Jourdan. 


in  the  substance  of  the  sterno-mastoid  with 
branches  coming  from  the  occipital  above  and 
others  from  the  thyroid  axis  inferiorly.  c.  Tin: 
laryngeal  often  arising  from  the  external  carotid, 
an  occurrence  which,  according  to  Meckel, 
takes  place  in  one  case  in  eight,  passes  into 
the  larynx  through  the  hyo-thyroid  membrane, 
sometimes  through  a  hole  in  the  thyroid  carti- 
lage ;  it  usually  accompanies  the  superior 
laryngeal  nerve :  its  branches  are  lost  in  the 
internal  muscles  and  mucous  membrane  of  the 
larynx  and  the  epiglottis.  Before  it  enters  the 
larynx  it  gives  branches,  some  of  which  ascend 
to  anastomose  with  the  hyoidean,  others  de- 
scend to  the  thyroid  body ;  one  of  these  latter 
is  remarkable  for  running  across  the  front  of 
the  crico-thyroid  membrane  to  anastomose  with 
a  similar  branch  from  the  opposite  side;  it 
generally  lies  in  the  situation  in  which  laryn- 
gotomy  is  performed.  Having  given  off  the 
above-mentioned  branches,  and  arrived  at  the 
superior  extremity  of  the  thyroid  body,  the 
thyroid  artery  divides  into  two  branches,  one 
of  which  descends  along  its  external  edge, 
sending  off  numerous  branches  which  are  lost 
in  its  substance,  anastomosing  freely  with  the 
inferior  thyroid,  the  other  branch  descends 
coursing  along  the  superior  border  of  that  body 
on  which  it  expends  its  branches,  and  arriving 
at  the  mesial  line  below  the  cricoid  cartilage, 
anastomoses  with  the  corresponding  artery  from 
the  opposite  side:  occasionally  this  branch 
supplies  the  small  artery  which  crosses  the 
crico-thyroid  membrane. 

2.  The  Lingual  Artery  (A.  lingualis)  arises 
after  the  thyroid,  and  sometimes,  but  rarely, 
from  a  common  trunk  with  the  thyroid,  comes 
at  other  times  and  not  unfrequently  from  the 
facial.  This  artery  forms  in  its  course  a  con- 
siderable curve,  the  convexity  of  which  is 
upwards ;  it  passes  forwards  and  inwards  above 
the  cornu  of  the  os  hyoides,  between  the  mid- 
dle constrictor  of  the  pharynx  and  hyo-glossus, 
and  mounts  up  towards  the  base  of  the  tongue, 
between  the  hyo-glossus  and  sublingual  gland 
which  lie  to  its  outer  side,  and  the  genio-glossus 
which  is  internal  to  it ;  then  taking  a  horizontal 
direction,  it  passes  forwards  under  the  name  of 
ranine  artery,  in  company  with  the  hypo-glossal 
nerve,  coursing  between  the  genio-glossus  and 
lingualis  muscles,  as  far  as  the  point  of  the 
tongue  where  it  anastomoses  with  its  fellow  of 
the  opposite  side.  After  its  origin  and  before 
it  passes  under  the  posterior  edge  of  the  hyo- 
glossus  muscle,  this  artery  runs  superficially  be- 
neath the  common  coverings  of  the  neck,  lying 
on  the  middle  constrictor  of  the  pharynx  above 
the  cornu  of  the  os  hyoides;  superior  to  it  lie 
the  tendon  of  the  digastric  muscle,  the  stylo- 
hyoid  muscle  and  the  hypo-glossal  nerve, 
which  after  sending  a  filament  across  it  to  the 
hyo-thyroid  muscle,  continues  its  course  for- 
wards on  the  cutaneous  surface  of  the  hyo- 
glossus  muscle  which  separates  the  lingual 
nerve  and  arteiy  in  this  part  of  their  course. 

Branches. — Having  given  a  few  inconsi- 
derable twigs  to  the  middle  constrictor,  stylo- 
glossus,  digastric,  and  stylo-hyoid  muscles, 
and  to  the  sublingual  gland,  &c.;  the  lingual 


486 


CAROTID  ARTERY. 


artery  sends  off  the  following  branches,  a, 
The  hyoidean  branch,  arising  at  the  external 
edge  of  the  hyoglossus  muscle,  passes  be- 
tween the  genio-hyoideus  and  genio-glossus, 
and  coming  forward  in  the  mesial  line,  de- 
scends over  the  front  of  the  body  of  the  os 
hyoides,  and  anastomoses  with  the  hyoidean 
branch  of  the  thyroid  artery,  giving  branches 
to  the  muscles,  in  the  vicinity  of  which  it 
passes  and  to  the  integuments.  by  The  dorsalis 
lingua,  arising  under  cover  of  the  hyoglossus, 
passes  upwards  and  outwards,  crossing  the 
stylo-glossus  and  distributes  its  branches  over 
the  posterior  part  of  the  dorsum  of  the  tongue, 
the  tonsils,  velum  palati,  and  epiglottis,  where 
it  anastomoses  with  the  laryngeal  branch  of 
the  superior  thyroid.  At  the  internal  edge 
of  the  hyoglossus  the  lingual  artery  divides 
into  the  sublingual  and  ranine.  c,  The  sub- 
lingual  branch  passes  forwards  between  the 
mylo-hyoid  and  genio-glossus  muscles  and 
above  the  sublingual  gland,  to  which  it  is 
principally  distributed,  as  well  as  to  the 
muscles  of  the  tongue  and  the  mucous  mem- 
brane of  the  mouth.  Occasionally  we  find 
the  place  of  the  sublingual  artery  supplied  by 
the  submental,  a  branch  of  the  facial,  d,  The 
ranine  artery,  which  is  the  continuation  of  the 
trunk  of  the  lingual,  passes  forward  between  the 
genio-glossus  and  lingualis,  and  running  along 
the  under  surface  of  the  tongue  by  the  side 
of  the  attachment  of  the  frsenum,  sends  nu- 
merous branches  into  the  substance  of  that 
organ,  and  ends  by  anastomosing  with  the 
ranine  of  the  opposite  side.  It  is  this  artery 
which  is  endangered  if  the  scissors  be  directed 
too  much  upwards  in  dividing  the  fraenum 
linguae  in  children. 

3.  The  labial  artery,  called  also  facial  or 
external  maxillary,  (a.  facialis  v.  maxillaris 
externa,)  varies  very  much  in  its  origin,  size, 
and  the  extent  of  its  distribution.  It  is  usually 
the  largest  of  the  three  anterior  branches  of 
the  external  carotid,  and  supplies  the  whole 
of  the  anterior  part  of  the  face ;  sometimes, 
however,  it  only  extends  as  far  as  the  angle 
of  the  mouth,  beyond  which  its  place  is 
supplied  by  the  temporal  artery.  There  is, 
perhaps,  no  other  artery  which  presents  so 
many  varieties,  even  on  opposite  sides  of  the 
body  in  the  same  subject.  From  its  origin 
it  proceeds,  in  a  tortuous  course,  inwards 
and  forwards,  towards  the  internal  part  of  the 
angle  of  the  lower  jaw,  covered  by  the  hypo- 
glossal  nerve,  the  digastric  and  stylo-hyoid 
muscles :  it  then  passes  between  the  lower 
jaw  and  submaxillary  gland,  lodged  in  a 
groove  in  that  gland ;  after  which  it  turns 
over  the  inferior  border  of  the  lower  jaw,  and 
arrives  on  the  external  surface  of  that  bone 
a  little  in  front  of  the  anterior  edge  of  the 
masseter  muscle :  from  this  it  ascends  tor- 
tuously towards  the  commissure  of  the  lips, 
covered  by  the  skin  and  the  platysma  ;  thence 
passing  upwards  and  inwards  under  the  zygo- 
matic  muscles,  and  over  the  buccinator  and 
levator  anguli  oris,  it  continues  to  ascend  in 
the  groove  between  the  cheek  and  the  upper 
lip  and  by  the  side  of  the  nose,  to  the  internal 


canthus  of  the  eye,  where,  very  much  dimi- 
nished in  size,  it  terminates  by  anastomosing 
with  the  nasal  branch  of  the  ophthalmic  artery. 

Branches.—  The  branches  of  the  labial  artery 
are  very  numerous.  a,  The  inferior  palatine, 
which  arises  from  the  labial  close  to  its  origin; 
this  vessel  sometimes  comes  from  the  trunk 
of  the  carotid  itself,  it  passes  upwards  between 
the  stylo-pharyngeus  and  stylo-glossus,  to 
which  it  gives  branches  :  it  then  attaches  itself 
to  the  superior  and  lateral  part  of  the  pharynx, 
supplying  this  region,  the  tongue,  and  the 
tonsil.  Having  reached  the  velum  palati,  it 
divides  into  many  branches,  which  are  dis- 
tributed to  the  muscles,  mucous  membrane, 
and  glands  of  that  organ,  and  to  the  Eustachian 
tube.  These  branches  anastomose  with  the 
superior  palatine  branch  of  the  internal  max- 
illary. The  tonsillitic  artery,  (arteria  tonsil- 
laris  of  Soemmerring,)  enumerated  as  a  dis- 
tinct branch  of  the  labial  by  Professor  Harrison, 
is,  more  properly  speaking,  a  branch  of  the 
inferior  palatine. 

In  passing  through  the  sub-maxillary  gland, 
the  labial  artery  gives  off  several  branches  to 
this  gland,  the  internal  pterygoid  muscle, 
and  the  mucous  membrane  of  the  mouth  :  as 
it  is  about  to  turn  over  the  side  of  the  lower 
jaw,  there  arises  from  it  a  branch  of  more 
considerable  size,  namely,  b,  the  submental 
branch.  This  artery  passes  forwards  beneath 
the  base  of  the  lower  jaw,  covered  by  the 
platysma  and  anterior  belly  of  the  digastric, 
between  which  and  the  mylo-hyoideus  it  takes 
its  course  towards  the  symphysis  of  the  chin, 
distributing  branches  to  supply  the  muscles 
and  integuments  in  this  region  and  to  anasto- 
mose with  the  sublingual ;  some  of  its  branches 
mount  over  the  chin  and  communicate  with 
the  arteries  of  the  lower  lip :  the  submental 
artery  sometimes  furnishes  the  sublingual,  and 
at  other  times  it  is  given  off  by  this  latter. 

From  the  inferior  border  of  the  lower  jaw 
to  the  commissure  of  the  lips,  the  labial  gives 
several  branches,  some  of  which  are  anterior 
and  some  posterior:  the  posterior  are  com- 
paratively insignificant  branches  distributed  to 
the  masseter,  platysma,  buccinator,  parotid 
gland  and  duct,  the  cellular  tissue  and  in- 
teguments of  the  cheek,  which  communicate 
with  branches  of  the  transverse  facial.  Besides 
smaller  branches  given  off  anteriorly  to  the 
lips,  there  are  two  considerable  branches  and 
one  of  lesser  size,  which  require  a  more  par- 
ticular description ;  viz.  c,  the  inferior  labial 
coronary  arises  about  midway  between  the 
commissure  of  the  lips  and  the  base  of  the 
lower  jaw,  it  passes  under  the  triangularis  oris 
muscle,  to  which,  as  well  as  to  the  quadratus, 
levator  labii  inferioris,  and  mucous  membrane 
of  the  mouth,  it  gives  numerous  branches  and 
anastomoses  with  its  congener,  and  the  mental 
branch  of  the  inferior  dental.  This  artery  is 
sometimes  smaller  on  one  side  than  on  the 
other;  it  is  sometimes  absent  on  one  side, 
when  its  place  is  supplied  by  the  artery  of 
the  opposite  side;  sometimes  it  arises  from 
the  superior  labial  coronary;  sometimes  it  is 
double.  After  having  given  off  this  branch, 


CAROTID  ARTERY. 


487 


the  facial  artery  continues  its  course  upwards 
and  inwards,  and,  opposite  the  commissure 
of  the  lips,  gives  off  d,  the  superior  labial 
coronary  artery.  This  vessel  passes  inwards 
among  the  fibres  of  the  orbicularis  oris,  runs 
above  the  free  border  of  the  upper  lip  nearer 
to  its  mucous  membrane  than  to  its  cutaneous 
surface,  gives  branches  to  the  various  parts 
composing  the  upper  lip,  and  meets  the  co- 
ronary of  the  opposite  side,  with  which  it 
very  freely  anastomoses.  The  superior  labial 
coronary  always  sends  off  from  the  place 
where  it  anastomoses  with  that  of  the  opposite 
side  a  branch,  which  ascends  towards  the 
septum  of  the  nose,  and  which  is  called  the 
artery  of  the  septum  of  the  nose,  (arteria 
septi  nasi.)  The  place  of  this  artery  is  some- 
times occupied  by  two  or  more  branches ;  it 
divides,  near  the  septum  of  the  nose,  into 
at  least  two  branches,  which  pass,  one  on  either 
side,  along  the  inferior  border  of  the  septum 
to  the  extremity  of  the  nose,  where  it  anasto- 
moses with  branches  of  the  lateral  nasal : 
sometimes  the  superior  coronary  gives  off  a 
branch  (ramus  p'mnalis),  as  it  passes  the  ala 
of  the  nose,  to  which,  and  the  external  part 
of  the  nostril,  it  is  distributed. 

After  the  origin  of  the  superior  labial  the 
facial  artery  is  reduced  to  a  very  small  size, 
and  its  continuation  is  by  some  called  the 
external  nasal,  arteria  nasalis  externa  corn- 
munis.  It  continues  to  pass  obliquely  up- 
wards, forwards,  and  inwards  under  the  levator 
labii  superioris,  to  which  it  gives  branches : 
after  anastomosing  with  the  infra-orbital  artery 
and  giving  off  branches,  which  pass  forward 
on  the  lateral  surface  of  the  nose,  namely,  e, 
laterales  nasi,  andy,  dorsales  nasi,  which  freely 
anastomose  with  each  other,  with  the  artery  of 
the  septum,  and  those  of  the  opposite  side 
on  the  dorsum  of  the  nose,  it  emerges  from 
between  the  two  heads  of  the  levator  labii 
superioris,  and  becoming  subcutaneous,  ter- 
minates at  the  inner  canthus  of  the  eye  by 
anastomosing  with  the  termination  of  the  nasal 
branch  of  the  ophthalmic,  at  which  place  it  has 
received  the  name  of  the  angular  artery. 

Irregularities  of  the  labial  or  facial  artery. 
It  sometimes  happens  that  the  facial  artery  is 
smaller  than  usual,  and  terminates  at  the  angle 
of  the  mouth  or  even  below  the  situation  of 
the  usual  origin  of  the  inferior  coronary;  in 
this  case  the  transverse  facial  branch  of  the 
temporal  generally  fnrnishes  the  branches  which 
the  coronary  has  failed  to  produce;  on  the 
other  hand  the  labial  artery  is  sometimes  of  a 
larger  size  than  usual,  as  happens  when  it 
furnishes  supernumerary  branches,  such  as  the 
ranine  or  sublingual.  The  facial  artery  is  the 
principal  source  of  communication  between  the 
superficial  and  deep  branches  of  the  external 
carotid  by  its  anastomoses  with  the  infra-orbital, 
nasal  and  dental  arteries ;  and  of  the  external 
carotid  with  the  internal,  by  its  anastomoses 
with  the  ophthalmic. 

Internal  branch  of  the  external  carotid, 
Inferior  pharyngeal  artery,  (a.  pharyngea  in- 
ferior v.  ascendens,)  arises  commonly  from  the 
internal  side  of  the  external  carotid  close  to  its 


origin,  sometimes  from  the  bifurcation  of  the 
primitive  carotid,  more  rarely  from  the  internal 
carotid,  and  occasionally  from  the  occipital; 
sometimes  its  place  is  supplied  by  the  inferior 
palatine  or  by  branches  from  the  trunk  of  the 
facial ;  sometimes  it  is  double,  in  which  case 
only  one  of  its  branches  arises  from  the  external 
carotid,  the  other  being  furnished  by  one  of 
the  smaller  arteries  already  mentioned,  or  by 
the  internal  carotid ;  this  artery  is  always  the 
smallest  branch  of  the  external  carotid;  it 
passes  perpendicularly  upwards  internal  to  the 
external  carotid  between  the  trunk  of  that 
vessel  and  the  pharynx,  lying  on  the  rectus 
capitis  anticus  major  muscle,  and  closely  re- 
lated to  the  superior  cervical  ganglion  of  the 
sympathetic.  Having  furnished  branches  from 
its  inner  side,  both  ascending  and  descending, 
to  the  constrictors  of  the  pharynx  and  other 
muscles,  which  also  supply  the  mucous  mem- 
brane, and  from  its  external  side  to  the  deep 
muscles  of  the  neck,  it  terminates  at  the  basis 
cranii,  near  the  petrous  portion  of  the  temporal 
bone,  by  giving  off  its  terminal  branches,  of 
which  one,  the  proper  pharyngeal,  is  princi- 
pally distributed  to  the  parietes  of  the  pharynx, 
and  communicates  by  anastomosis  with  the 
inferior  palatine  from  the  superior  thyroid  ;  a 
second,  the  posterior  tneningeal  artery,  enters 
the  cranium  by  the  foramen  lacerum  posterius, 
or  by  an  opening  in  the  vicinity  of  the  condyle 
of  the  occipital  bone,  and  is  distributed  to  the 
dura  mater  lining  the  inferior  occipital  fossa : 
and  a  third  ascends  to  the  basis  cranii,  and  per- 
forates the  cartilaginous  lamella,  which  fills  up 
the  foramen  lacerum  posterius,  to  enter  the 
cranium  and  be  distributed  to  the  dura  mater. 

POSTERIOR  BRANCHES  OF  THE  EXTERNAL 
CAROTID. — 1st.  The  occipital  artery  (a.  occi- 
pitalis)  arises  from  the  posterior  side  of  the 
external  carotid,  opposite  the  lingual  or  the 
facial ;  it  sometimes  but  rarely  comes  from  the 
internal  carotid  ;  it  passes  at  first  a  little  ob- 
liquely backwards  along  the  lower  border  of 
the  posterior  belly  of  the  digastric  muscle 
which  overlaps  it;  it  crosses  over  the  ninth  pair 
of  nerves  which  winds  beneath  it  just  at  its 
origin,  the  internal  carotid  artery,  internal 
jugular  vein,  and  spinal  accessory  nerve ;  and 
passing  backwards  between  the  transverse  pro- 
cess of  the  atlas  and  the  mastoid  process  of 
the  temporal  bone  it  is  lodged  in  a  groove  in 
this  latter  bone,  which  is  internal  to  the  inser- 
tion of  the  posterior  belly  of  the  digastric ;  it 
crosses  the  outer  border  of  the  rectus  capitis 
lateralis  muscle,  and  continuing  its  course 
beneath  the  sterno-cleido-mastoid,  trachelo- 
mastoid,  splenius  capitis  and  trapezius,  and 
over  the  obliquus  superior  and  complexus,  it 
ascends  tortuously  over  the  superior  part  of  the 
occipital  bone,  where  it  becomes  cutaneous 
and  anastomoses  with  branches  from  the  tem- 
poral, posterior  auris,  and  opposite  occipital. 
The  first  branches  of  the  occipital  are  small, 
and  are  distributed  to  the  sterno-mastoid,  di- 
gastric, and  stylo-hyoid  muscles,  and  to  the 
lymphatic  glands  in  the  neighbourhood ;  the 
branches  which  enter  the  sterno-mastoid  are 
sometimes  considerable,  and  anastomose  freely 


488 


CAROTID  ARTERY. 


in  the  substance  of  that  muscle  with  the  branches 
which  it  receives  from  the  superior  thyroid. 

The  sterno-mastoid  muscle  very  frequently 
receives  a  large  branch  at  this  part  arising  dis- 
tinctly from  the  external  carotid.  This  Professor 
Harrison  considers  should  be  classed  among 
the  regular  branches  of  the  external  carotid, 
and  he  has  described  it  under  the  name  of-  a. 
sterno-mastoidea.* 

While  the  occipital  artery  is  covered  by  the 
sterno-mastoid,  trachelo-mastoid,  and  splenius, 
it  gives  branches  to  these  muscles,  some  of 
which  descending  anastomose  with  branches  of 
the  cervicalis  profunda  and  the  vertebral ; 
those  which  ascend  are  distributed  to  the  supe- 
rior attachments  of  these  muscles ;  amongst 
them  there  is  one  branch  occasionally  found 
which  penetrates  into  the  cranium  by  the  mas- 
toid  hole,  and  is  distributed  to  the  dura  mater, 
under  the  name  of  posterior  meningeal  of  the 
occipital. 

When  the  occipital  artery  comes  out  from 
beneath  the  splenius  muscle  it  divides  into 
those  branches  which  are  distributed  over  the 
posterior  surface  of  the  occipital  bone,  sup- 
plying the  occipito-frontalis  and  the  scalp,  to- 
gether with  the  pericranium,  and  anastomosing, 
as  already  mentioned,  with  the  opposite  occi- 
pital, posterior  auris,  and  temporal.  One  of 
these  branches  frequently  enters  the  cranium 
by  the  parietal  hole,  and  spreads  over  the  dura 
mater. 

The  occipital  artery  sometimes  gives  small 
twigs,  which  enter  the  cranium  by  the  foramen 
lacerum  posterius  and  the  anterior  condyloid 
foramen. 

2d.  A.  posterior  auris,  v.  auricularis  pos- 
terior, arises  immediately  after  the  occipital, 
in  the  substance  of  the  parotid  gland ;  it  is 
generally  a  much  smaller  vessel  than  the  latter, 
from  which  it  is  mostly  separated  by  the  stylo- 
hyoid  muscle:  sometimes  it  comes  from  the 
occipital.  It  passes  upwards  and  backwards 
under  the  parotid  gland  between  the  mastoid 
process  of  the  temporal  bone  and  the  cartila- 
ginous tube  of  the  ear ;  it  first  sends  branches 
to  the  parotid  gland,  the  stylo-hyoid  muscle, 
the  posterior  belly  of  the  digastric  and  the 
external  ear;  it  then  gives  off  the  stylo- 
mastoid  artery,  which,  among  other  branches 
to  the  external  ear,  gives  off  one  to  be  dis- 
tributed to  the  membrana  tympani.  Then 
the  stylo-mastoid  traversing  the  aqueduct 
of  Fallopius  finds  its  way  into  the  cavity  of 
the  tympanum,  on  the  lining  membrane  of 
which,  and  its  prolongation  into  the  mastoid 
cells,  its  branches  are  expended,  where  it  anas- 
tomoses with  a  branch  of  the  middle  menin- 
geal, which  enters  the  hiatus  Fallopii,  and 
arrives  in  the  tympanum  along  with  the  chorda 
tympani  nerve.  Sometimes  the  stylo-mastoid 
artery  comes  from  the  middle  meningeal. 

When  the  posterior  auris  gets  to  the  front  of 
the  mastoid  process  it  divides  into  two  branches, 
one  of  which  is  anterior  and  the  other  pos- 
terior ;  the  former  spreads  its  branches  over  all 

*  Surgical  Anatomy  of  the  Arteries  of  the  Human 
Body,  vol.  i. 


parts  of  the  internal  surface  of  the  ear ;  the 
latter  ascends  in  front  of  the  mastoid  process, 
passes  under  the  posterior  auris  muscle,  and 
divides  into  many  branches,  which  are  distri- 
buted to  the  occipito-frontalis  and  temporal 
muscles,  integuments,  &c. 

These  branches  anastomose  with  the  temporal 
and  occipital  arteries.* 

While  traversing  the  parotid  gland  the  ex- 
ternal carotid  gives  several  small  branches  to 
the  masseter  and  pterygoid  muscles,  to  the 
substance  of  the  gland  itself,  and  a  few  to  the 
front  of  the  external  ear ;  occasionally  it  gives 
origin  to  the  transversalis  faciei  in  this  course. 

Behind  the  neck  of  the  condyle  of  the  lower 
jaw  the  external  carotid  divides  into  its  two 
superior  and  terminal  branches,  the  temporal 
and  internal  maxillary. 

1.  Temporal  artery,  (a.  temporalis.)  The 
temporal  artery  ascends  at  first  a  little  obliquely 
outwards  between  the  ramus  of  the  jaw  and 
the  tube  of  the  ear,  covered  by  the  parotid 
gland ;  crossing  the  zygoma  at  its  posterior 
part,  and  passing  under  the  anterior  auris 
muscle,  it  mounts  up  over  the  temporal  apo- 
neurosis,  and  becomes  subcutaneous  for  the 
remainder  of  its  course. 

Immediately  after  its  origin  the  temporal 
gives  off  anteriorly  a  very  considerable 
branch,  which  is  called  the  transversalis  faciei : 
this  artery  sometimes  arises  from  the  trunk  of 
the  external  carotid ;  it  passes  forward  over  the 
neck  of  the  condyle  of  the  lower  jaw,  and, 
crossing  the  masseter  muscle,  runs  superior  to 
the  duct  of  Steno,  which  it  accompanies  across 
the  face;  it  anastomoses  with  the  labial,  buccal, 
and  infra-orbital  arteries.  The  branches  which 
the  transversalis  faciei  usually  gives  off  are 
distributed  to  the  parotid  gland  and  its  duct, 
the  masseter,  zygomatic,  and  orbicularis  pal- 
pebrarum  muscles,  and  the  integuments.  I 
have  seen  an  instance  in  which  this  artery  arose 
from  the  external  carotid  opposite  the  angle  of 
the  jaw,  beneath  which  it  passed  forwards,  and 
joined  the  labial  at  the  anterior  edge  of  the 
masseter  muscle. 

When  the  temporal  artery  has  arrived  at  the 
zygoma,  it  gives  a  branch  called  middle  tem- 
poral, which  pierces  the  temporal  aponeurosis, 
and  ascends  in  the  substance  of  the  temporal 
muscle,  to  which  it  is  distributed,  and  which 
anastomoses  with  the  deep  temporal  arteries. 

Having  given  off  a  few  small  branches  to 
the  parotid  gland,  integuments,  and  external 
ear,  the  temporal  artery  ascends  on  the  temporal 
aponeurosis,  and  divides  into  two  branches, 
the  anterior  and  posterior.  The  anterior  branch 
ascends  in  a  serpentine  course  towards  the 
forehead,  and  sends  off  many  branches,  which 
are  distributed  to  the  occipito-frontalis,  the 
orbicularis  palpebrarum,  and  integuments,  and 
which  anastomose  with  the  superciliary  and 

*  [The  surgical  anatomist  cannot  fail  to  notice 
the  relation  of  the  posterior  auris  artery  to  the  portio 
dura  nerve,  as  it  lies  superficial  to  and  nearer  the 
mastoid  process  than  that  nerve,  so  as  to  be  consi- 
derably, although  not  necessarily,  endangered  when 
the  operator  proceeds  to  divide  the  nerve  at  its 
emergence  from  the  stylo  -mastoid  foramen. — ED.] 


CAROTID  ARTERY. 


489 


frontal  branches  of  the  ophthalmic  and  with 
the  opposite  temporal.  The  posterior  branch 
passes  upwards  and  backwards  in  a  tortuous 
course,  and  supplies  the  integuments,  tem- 
poral aponeurosis,  pericranium,  &c.  These 
branches  anastomose  with  the  anterior  branch, 
with  the  opposite  temporal,  the  occipital,  and 
posterior  auris. 

2.  The  internal  maxillary  artery,  (a.  max II- 
laris  intcnia,)  is  larger  than  the  preceding;  im- 
mediately after  its  origin  it  passes  downwards 
and  inwards  under  the  neck  of  the  condyle  of 
the  lower  jaw ;  it  then  mounts  forwards  and  in- 
wards between  the  temporal  and  external  ptery- 
goid  muscles,  and  usually  passing  between  the 
two  origins  of  the  latter,  it  enters  the  pterygo- 
maxillary  fossa,  where  it  ascends  as  high  as 
the  level  of  the  inferior  wall  of  the  orbit,  oppo- 
site which  it  takes  a  horizontal  direction.  At 
this  place  it  divides  into  numerous  branches, 
which  are  distributed  on  one  side  inwards  to- 
wards the  nose,  and  on  the  other  side  to  the 
external  part  of  the  face. 

The  branches  of  the  internal  maxillary  are, 
a.  the  middle  meningeal,  b.  the  inferior  dental, 
c.  the  posterior  deep  temporal,  d.  the  masseteric, 
e.  pterygoid  branches,  f.  the  buccal,  g.  the  an- 
terior deep  temporal,  h.  the  alveolar,  i.  the 
infra-orbital,  L  the  superior  palatine,  m.  the 
vidian,  71.  the  pterygo-pulatine,  and  o.  the 
spheno-palutine :  in  addition  to  these  the  in- 
ternal maxillary  artery  gives  several  branches  to 
the  cellular  tissue  and  other  parts  surrounding  it. 

a.  The  middle  meningeal  artery  (a.  meningea 
media,  spinosa)  arises  from  the  superior  part  of 
the  artery  and  passes  directly  upwards  on  the 
inside  of  the  external  pterygoid  muscle,  to 
which,  to  the  superior  constrictor  of  the  pharynx 
and  muscles  of  the  velum  palati  it  sends 
branches,  and  passing  between  the  tensor 
palati  muscle  and  internal  lateral  ligament  of 
the  temporo-maxillary  articulation,  enters  the 
cranium  through  the  foramen  spinale  of  the 
sphenoid  bone,  and  immediately  gives  off  some 
small  branches,  which  pass  through  the  hiatus 
Fallopii  to  the  cavity  of  the  tympanum,  where 
they  anastomose  with  the  stylo-mastoid  artery; 
other  branches  pass  forwards  towards  the  orbit 
into  which  some  of  them  occasionally  enter  by 
the  foramen  lacerum.  The  meningeal  artery 
then  divides  into  two  branches,  an  anterior  and 
a  posterior ;  the  anterior,  which  is  the  larger, 
might  be  considered  as  the  continued  trunk;  it 
mounts  forwards  towards  the  anterior  inferior 
angle  of  the  parietal  bone,  where  it  is  lodged  in 
a  groove,  and  sometimes  in  a  canal  in  the  sub- 
stance of  that  bone.  This  branch  at  first  gives 
twigs  to  the  foramen  lacerum,  which  anastomose 
with  the  lachrymal ;  after  which  it  mounts  on 
the  parietal  bone,  principally  following  the 
course  of  the  coronal  suture,  sending  its  bran- 
ches upwards  and  backwards  between  the  dura 
mater  and  the  inner  surface  of  the  parietal 
bone.  The  posterior  branch  passes  backwards 
in  a  curved  direction  on  the  inner  surface  of  the 
squamous  portion  of  the  temporal  bone,  and 
advancing  towards  the  inferior  border  of  the 
parietal  bone,  is  expended  on  the  posterior  and 
lateral  part  of  the  dura  mater.  The  branches 


of  the  middle  meningeal  artery  spread  over  the 
external  surface  of  the  dura  mater,  and  occupy 
the  grooves  which  are  disposed  in  an  arbores*- 
cent  form  on  the  internal  surface  of  the  parietal 
bone.  The  middle  meningeal  artery  anasto- 
moses with  that  of  the  opposite  side  and  with 
the  other  arteries  of  the  dura  mater. 

b.  The  inferior  maxillary  or  inferior  dental 
artery  sometimes  coming  from  the  middle  me- 
ningeal, descends  to  the  posterior  dental  hole 
by  which  it  enters  the  dental  canal,  passing  be- 
tween the  inner  surface  of  the  ramus  of  the  jaw 
and  the  outer  surfaces  of  the  internal  pterygoid 
muscle  and  the  internal  lateral  ligament  of  the 
temporo-maxillary  articulation,  to  which  it  gives 
small  twigs :  before  it  enters  the  dental  hole,  it 
gives  off  a  small  branch,  which  passing  down- 
wards and  forwards  in  a  groove  on  the  inside 
of  the  lower  jaw,  is  distributed  to  the  mylo- 
hyoid  muscle  and  mucous  membrane  of  the 
mouth.     In  the  dental  canal  this  artery  passes 
forwards  beneath  the  alveoli  of  the  molar  teeth, 
sending  upwards  in  its  course  several  branches 
which  penetrate  into  the  alveoli,  and  enter  the 
cavities  of  the  teeth  by  the  holes  in  their  roots ; 
having  arrived   opposite   the   mental  hole,   it 
sends  a  branch  which  passes  onwards  beneath 
the  alveoli  of  the  canine  and  incisor  teeth,  to 
which  it  is  distributed  ;  while  the  continuation 
of  the  artery  coming  out  through  the  mental 
hole  is  distributed  to  the  muscles  of  the  lower 
lip,  where  it  anastomoses  with  the  labial. 

c.  The  posterior  deep  temporal  artery  arises 
after  the  dental ;  it  passes  upwards  between  the 
temporal  and  external  pterygoid  muscles,  and 
sinking  into  the  substance  of  the  former,  divides 
into  a  great  number  of  branches,  which  spread 
over  the  squamous   portion   of  the  temporal 
bone,  and  are  distributed  to  the  temporal  mus- 
cle and  pericranium.     This  artery  anastomoses 
with  the  anterior  deep  temporal,  the  middle, 
and  the  superficial  temporal. 

d.  The  masseteric  is  a  small  branch  often 
arising  from  the  posterior  deep  temporal;  it 
passes  outwards  between  the  posterior  border 
of  the  temporal  muscle  and  the  condyle  of  the 
lower  jaw,  and   enters  the  masseter   muscle, 
where   it  anastomoses   with   the   transversalis 
faciei. 

e  The  pterygoid  arteries  are  irregular  as  to 
number,  size,  and  origin ;  they  either  come 
from  the  trunk  of  the  internal  maxillary  or  the 
posterior  deep  temporal,  and  are  distributed  to 
the  pterygoid  muscles. 

f.  The  buccal  artery  does  not  always  arise 
from  the  internal  maxillary  itself;  it  sometimes 
comes  from   the  anterior  deep   temporal,  the 
alveolar,  or  infra-orbital.     It  passes  downwards 
and  forwards  between  the  internal   pterygoid 
muscle  and  ramus  of  the  lower  jaw,  and  ad- 
vances over  the  surface  of  the  buccinator  mus- 
cle, to  which  it  gives  branches,  as  well  as  to  the 
zygomatic  and  other  muscles  of  the  lip  :    it 
anastomoses  with  the  labial,  infra-orbital,  and 
transversalis  faciei. 

g.  The  anterior  deep  temporal  arises  from 
the  internal  maxillary,  near  the  outer  wall  of 
the  temporal  fossa  beneath  the  temporal  mus- 
cle, to  which  it  is   distributed ;   some  of  its 


490 


CAROTID  ARTERY. 


branches  enter  the  orbit  through  the  malar 
bone,  and  spread  over  the  lachrymal  gland, 
communicating  with  the  lachrymal  artery. 

h.  The  alveolar  artery  descends  forwards 
over  the  superior  maxillary  bone,  very  tortuous 
in  its  course ;  it  gives  two  or  three  twigs,  which 
pass  into  the  inferior  and  posterior  dental  fora- 
mina to  be  distributed  to  the  lining  membrane 
of  the  antrum  maxillare  and  the  molar  teeth ; 
the  other  branches  of  the  alveolar  artery  are 
distributed  to  the  gums,  to  the  buccinator,  to 
the  periosteum  of  the  superior  maxillary  bone, 
and  to  the  cellular  substance  of  the  cheek: 
they  communicate  with  the  infra-orbital,  labial 
and  buccal. 

i.  The  infra-orbital  artery  arises  from  the 
internal  maxillary  at  the  superior  part  of  the 
pterygo-maxillary  space ;  it  enters  the  infra- 
orbital  canal,  through  which  it  passes  forwards 
and  inwards,  sending  branches  into  the  orbit 
and  maxillary  sinus ;  passing  out  by  the  infra- 
orbital  hole  it  comes  forward  on  the  face 
behind  the  levator  labii  superioris,  and  termi- 
nates in  a  number  of  branches,  which  pass  into 
the  muscles  of  the  upper  lip,  and  anastomose 
with  the  labial,  alveolar,  buccal,  and  nasal 
branch  of  the  ophthalmic. 

The  remaining  branches  of  the  internal  max- 
illary are  given  off  in  the  pterygo-maxillary 
space;  of  these  the  first  is 

/.  The  superior  palatine  descends  behind 
the  tuberosity  of  the  superior  maxillary  bone 
in  the  palato-maxillary  canal :  it  usually  gives 
off  two  branches,  which  descend  through  holes 
in  the  pterygoid  process  of  the  palate  bone, 
and  are  distributed  to  the  soft  palate;  while 
the  trunk  of  the  superior  palatine  passing  out 
of  the  posterior  palatine  hole,  directs  itself  for- 
wards and  inwards  in  a  groove  on  the  surface 
of  the  hard  palate,  and  divides  into  numerous 
branches,  which  are  distributed  to  the  mucous 
membrane  and  glands  of  the  palate,  to  the 
gums,  and  to  the  superior  maxillary  bone ;  one 
of  these  branches  sometimes  passes  up  through 
the  foramen  incisivum  to  the  nasal  fossae. 

m.  The  vidian  artery  is  an  insignificant 
branch  which  traverses  the  vidian  canal  from 
before  backwards,  and  coming  out  of  its  poste- 
rior opening  is  distnbuted  to  the  Eustachian 
tube  and  the  roof  of  the  pharynx:  it  anasto- 
moses with  the  inferior  pharyngeal. 

n.  The  ptery go-palatine  or  superior  pha- 
ryngeal is  a  small  insignificant  branch,  which 
passes  through  the  ptery  go-palatine  hole,  and 
is  distributed  like  the  former  to  the  roof  of  the 
pharynx  and  Eustachian  tube,  sending  some 
branches  to  the  sphenoid  bone  and  the  mem- 
brane lining  its  sinuses. 

o.  The  spheno-palatine  artery  may  be  con- 
sidered the  termination  of  the  internal  maxil- 
lary ;  it  enters  by  the  spheno-palatine  hole  into 
the  posterior  part  of  the  nasal  fossae,  and  divides 
into  two  principal  branches ;  an  external  and 
an  internal;  the  internal  branch  passing  across 
the  roof  of  the  nasal  fossae  arrives  at  the  septum, 
on  which  its  branches  are  principally  distri- 
buted ;  it  also  supplies  branches  to  the  roof  of 
the  pharynx  and  the  posterior  ethmoidal  cells; 
the  external  branch  descends  on  the  lateral  wall 


of  the  nose,  sending  its  branches  over  the 
spongy  bones  and  into  the  antrum  maxillare  : 
these  branches  anastomose  with  the  ethmoidal 
branches  of  the  ophthalmic  artery. 

THE  INTERNAL  CAROTID  ARTERY,  (carotisin- 

terna  sen  cerebralis,  Soemm.  cerebrate  anterieure, 
Chaussier.^This  artery  is  larger  than  the  external 
carotid  in  the  foetus,  but  in  the  adult  is  only  equal 
in  size  to  that  vessel,  aud  sometimes  even  smaller. 
At  its  origin  it  takes  a  curve  outwards  so  as  to 
get  external  to  the  commencement  of  the  ex- 
ternal carotid;  it  then  mounts  upwards  and 
forwards  in  front  of  the  three  superior  cervical 
vertebrae,  and  making  a  few  contortions  along 
the  side  of  the  pharynx,  enters  the  foramen 
caroticum  of  the  temporal  bone,  traversing  the 
carotid  canal  of  that  bone  internal  to  the  ca- 
vernous sinus,  perforates  the  dura  mater  internal 
to  the  anterior  clinoid  process  of  the  sphenoid 
bone,  where  it  divides  into  two  large  branches, 
the  anterior  and  middle  cerebral. 

The  internal  carotid  artery  has  the  following 
relations  from  its  origin  to  the  place  where  it 
enters  the  foramen  caroticum  :  anteriorly  it  has 
the  external  carotid  and  its  branches  in  contact 
with  it  at  its  origin,  also  the  hypoglossal  or  lin- 
gual nerve,  and  as  it  passes  under  the  digastric 
muscle  it  also  slips  beneath  the  following  parts 
which  lie  between  it  and  the  external  carotid, 
the  styloid  process,  with  the  muscles  attached 
to  it,  part  of  the  parotid  gland,  the  glosso- 
pharyngeal  and  inferior  pharyngeal  nerves. 

Posteriorly  it  lies  on  the  rectus  capitis  anti- 
cus  major,  having  the  par  vagum  and  superior 
laryngeal  nerve  behind  it,  and  higher  up  the 
trunk  of  the  hypo-glossal  nerve  coming  from 
between  it  and  the  internal  jugular  vein. 

The  internal  jugular  vein  bounds  it  externally 
at  first,  but  passes  to  its  posterior  side  above 
where  it  gets  to  the  internal  side  of  the  root  of 
the  styloid  process.  Internally  the  carotid  ar- 
tery lies  on  the  side  of  the  pharynx  to  which  it 
is  more  closely  applied  towards  its  upper  part, 
lying  on  the  stylo-glossus  and  the  outer  surface 
of  the  superior  constrictor  muscles,  which  with 
some  cellular  membrane  and  a  venous  plexus 
separate  it  from  the  tonsil,  external  and  poste- 
rior to  which  it  lies,  at  the  distance  of  from  six 
to  eight  lines  in  the  natural  state  of  the  parts; 
but  when  that  gland  is  enlarged  in  consequence 
either  of  acute  inflammation  or  chronic  disease, 
the  distance  between  it  and  the  artery  is  dimi- 
nished so  much  as  to  expose  the  latter  to  some 
risk  of  being  wounded  in  opening  abscesses  in 
the  tonsil,  an  occurrence  of  which  the  records 
of  experience  are  not  without  examples.  In 
this  stage  of  its  course  the  internal  carotid 
seldom  gives  any  branches ;  occasionally,  how- 
ever, the  inferior  pharyngeal  or  the  occipital 
arises  from  it.  Having  entered  the  carotid 
canal,  the  artery  ascends  vertically,  then  turns 
forwards  and  inwards,  and  passing  out  of  the 
canal  opposite  the  posterior  clinoid  process,  it 
takes  a  second  turn  upwards,  then  forwards 
along  the  side  of  the  sella  turcica,  between  the 
layers  of  the  dura  mater  which  include  the  ca- 
vernous sinus,  between  which  latter  and  the 
bone  the  artery  is  situate.  At  the  anterior 
extremity  of  the  side  of  the  sella  turcica  it  makes 


CAROTID  ARTERY. 


491 


a  third  turn  upwards  under  the  anterior  clinoid 
process,  and  passing  backwards  and  a  little  in- 
wards it  perforates  the  dura  mater  between  the  in- 
ternal side  of  this  process  and  the  commissure  of 
the  optic  nerves.  The  only  vessels  which  it  gives 
from  its  entrance  into  the  foramen  caroticum  to 
the  place  where  it  perforates  the  dura  mater  are 
one  or  two  small  branches  which  perforate  the 
petrous  portion  of  the  temporal  bone,  and  pass 
to  the  cavity  of  the  tympanum,  and  as  it  lies 
beside  the  cavernous  sinus,  two  or  three  little 
twigs  to  the  dura  mater,  pituitary  gland,  body 
of  the  sphenoid  bone,  and  to  the  third,  fourth, 
fifth,  and  sixth  pairs  of  nerves  which  lie  ex- 
ternal to  it  and  in  contact  with  the  outer  or 
inner  wall  of  the  cavernous  sinus. 

The  ophthalmic  artery  arises  from  the  an- 
terior side  of  the  carotid  while  that  vessel  is 
passing  into  the  dura  mater,  by  the  side  of  the 
anterior  clinoid  process ;  it  enters  the  foramen 
opticum  at  first  external  and  inferior  to  the 
optic  nerve,  over  which  it  mounts  obliquely 
towards  its  internal  side,  passing  between  it  and 
the  superior  rectus  muscle  of  the  eye;  it  then 
directs  its  course  along  the  superior  and  internal 
part  of  the  orbit  between  the  obliquus  superior 
and  rectus  internus,  towards  the  inner  canthus 
of  the  eye  where  it  terminates.  Before  entering 
the  orbit  it  gives  off  a  few  small  twigs  to  the 
dura  mater  and  cavernous  sinus,  and  within 
the  orbit  it  furnishes  the  following  branches: — 
1.  the  lachrymal;  2.  the  arteria  centralis 
retinae;  3.  the  supra-orbital;  4.  the  ciliary;  5. 
the  muscular;  6.  the  ethmoidal;  7.  the  palpe- 
bral ;  8.  the  frontal ;  and  9.  the  nasal. 

The  order  in  which  these  arteries  arise  from 
the  ophthalmic  presents  many  varieties;  but 
they  are  constant  in  their  distribution. 

1.  The.  lachrymal  artery  is  one  of  the  largest 
branches  of  the  ophthalmic:  it  sometimes  comes 
from  the  middle  meningeal,  and  enters  the 
orbit  by  the  foramen  lacerum  orbitaleof  the  sphe- 
noid bone.  It  runs  forwards  between  the  ex- 
ternal wall  of  the  orbit  and  the  rectus  externus, 
giving  branches  to  that  muscle,  the  periosteum, 
levator  palpebrae  superioris  and  sheath  of  the 
optic  nerve.  One  of  its  branches  traverses  the 
malar  bone,  and  entering  the  temporal  fossa 
anastomoses  with  the  anterior  deep  temporal ; 
another  little  branch  frequently  traversing  this 
bone  passes  outwards  through  the  same  hole 
with  the  nervus  subcutaneus  malae,  and  anas- 
tomoses with  branches  of  the  transversalis  faciei. 
The  continuation  of  the  artery  then  divides  into 
several  branches  which  are  distributed  to  the 
lachrymal  gland  and  the  external  part  of  the 
upper  eyelid,  anastomosing  with  the  palpebral 
and  the  temporal  arteries. 

2.  The  central  artery  of  the  retina  (arteria 
centralis  retina)    penetrates  the  substance  of 
the  optic  nerve  to  enter  a  canal  in  its  centre, 
the  porus  opticus,  in  which  it  passes  forwards, 
and  is  distributed  to  the  retina,  the  vascular 
layer  of  which  it  forms  by  its  ramifications. 

3.  The  supra-orbital  arises  after  the  centralis 
retinae,  passes  forwards  along  the  superior  wall 
of  the  orbit  above  the  levator  palpebrae  supe- 
rioris and  superior  rectus,  giving  branches  to 
these  muscles,  the  periosteum,  and  the  scle- 


rotic :  on  reaching  the  margin  of  the  orbit,  it 
passes  out  through  the  superciliary  foramen, 
along  with  the  frontal  branch  of  the  ophthalmic 
nerve,  giving  in  its  passage  a  branch  which 
enters  the  substance  of  the  frontal  bone ;  this 
artery  then  mounts  beneath  the  corrugator  su- 
percilii  and  orbicularis  palpebrarurn  muscles, 
and  is  expended  on  these  muscles,  the  occipito- 
frontalis  and  the  integuments ;  it  anastomoses 
with  branches  of  the  lachrymal  and  frontal. 

4.  The  ciliary  arteries  sometimes  amount  in 
number  to  thirty  or  forty;  they  consist  of  three 
sets :  the  posterior  or  short,  the  long,  and  the 
anterior.  The  posterior  ciliary  arteries  are  very 
numerous,  sometimes  amounting  in  number  to 
thirty  or  forty:  although  mostly  arising  from 
the  ophthalmic,  some  of  them  come  from  the 
inferior  muscular,  the  supra-orbital,  posterior 
ethmoidal  or  lachrymal;  they  run  along  the 
optic  nerve  very  tortuous,  and  entangled  with 
the  ciliary  nerves,  anastomosing  freely  with 
each  other. 

The  posterior  or  short  ciliary  arteries  pierce 
the  sclerotic  close  to  the  entrance  of  the  optic 
nerve ;  some  of  their  branches  are  distributed 
to  that  membrane  in  which  they  anastomose 
with  branches  from  the  muscular  arteries ; 
while  all  the  others  advance  nearly  parallel, 
dividing  at  very  acute  angles  into  numerous 
smaller  twigs;  these  branches  are  at  first  ex- 
ternal to  the  choroid  ;  but  in  their  course  for- 
wards they  penetrate  to  the  internal  surface  of 
that  membrane,  and  becoming  more  numerous 
from  having  undergone  new  subdivisions,  form 
a  network  of  anastomoses  from  which  several 
branches  are  sent  to  the  ciliary  margin  of  the 
iris,  where  they  anastomose  with  the  anterior 
ciliary,  but  a  greater  number  are  given  to  the 
ciliary  processes  in  the  centre  of  which  they 
form  a  very  fine  network,  and  finally  end  in  a 
circle  of  anastomoses  surrounding  the  margin 
of  the  circle  in  which  these  processes  terminate 
internally. 

The  long  ciliary  arteries  are  two  in  number, 
one  internal,  the  other  external ;  they  are  larger 
than  the  short  ciliary  arteries  among  which  they 
arise,  but  pierce  the  sclerotic  obliquely  at  a 
greater  distance  from  the  optic  nerve ;  they 
pass  forwards  between  the  sclerotic  and  cho- 
roid, and  having  arrived  at  the  ciliary  ligament, 
they  divide  each  into  two  long  branches  which 
separate  from  each  other  at  obtuse  angles,  and, 
coursing  along  the  ciliary  margin  of  the  iris, 
form  a  circle  around  the  greater  circumference 
of  that  membrane  which  receives  branches  of 
anastomosis  from  the  short  ciliary  arteries. 
From  the  interior  of  this  circle  numerous 
branches  arise,  each  of  which  divides  into  two, 
which  diverge  at  obtuse  angles,  and,  anastomo- 
sing with  each  other  and  with  the  anterior 
ciliary,  form  another  arterial  circle  within  the 
former.  Thus  there  are  two  arterial  circles,  one 
within  the  other  at  the  greater  circumference  of 
the  iris.  From  the  concavity  of  this  inner 
circle  the  arteries  of  the  iris  arise.  These  arte- 
ries are  very  numerous ;  they  converge  in  ser- 
pentine lines  towards  the  papillary  margin  of 
the  iris,  where  they  anastomose,  in  the  manner 
of  the  mesenteric  arteries,  to  form  the  lesser 


492 


CAROTID  ARTERY. 


arterial  circle  of  the  iris.  All  these  arteries, 
however,  do  not  contribute  to  form  this  lesser 
arterial  circle  ;  a  great  number  pass  beyond  it, 
and,  along  with  the  branches  which  arise  from 
its  concavity,  advance  towards  the  pupil.  There 
are  thus  three  arterial  circles  in  the  iris,  two 
close  together  at  its  greater  circumference  or 
ciliary  margin;  the  third  much  smaller,  sur- 
rounding its  pupillary  margin,  and  commu- 
nicating with  the  preceding  by  a  radiation  of 
branches  situated  on  the  anterior  surface  of  the 
iris. 

The  anterior  ciliary  arteries  are  two  or  three 
in  number ;  sometimes  coming  from  the  palpe- 
bral  or  from  the  branches  which  go  to  the  recti 
muscles ;  they  pass  forward  to  the  anterior  part 
of  the  globe  of  the  eye,  where  they  each  di- 
vide into  many  branches,  the  smaller  of  which 
are  distributed  to  the  conjunctiva  and  the  scle- 
rotica,  the  others  pierce  the  sclerotica,  near  the 
circumference  of  the  cornea,  pass  through  the 
ciliary  ligament,  and  join  the  arterial  circles  of 
the  greater  circumference  of  the  iris ;  some 
passing  beyond  that  circle  go  to  the  iris,  and 
others  are  distributed  to  the  anterior  part  of  the 
choroid. 

5.  The  muscular  arteries  generally  consist  of 
two,  an  inferior  and  a  superior.     The  inferior 
muscular  artery  is  a  branch  which  is  generally 
present;  it  sometimes  gives  off  the   centralis 
retinae  and  one  or  more  ciliary;  it  passes  in- 
wards to  supply  the  inferior  and  internal  recti 
muscles,    and  sends  some  branches   into  the 
nasal  fossae. 

The  superior  muscular  is  less  regular  than 
the  former;  it  passes  forwards  im  mediately 
under  the  superior  wall  of  the  orbit,  and  di- 
vides into  many  branches,  which  are  distributed 
to  the  superior  and  internal  recti,  the  superior 
oblique,  the  levator  palpebrse  superioris,  the 
periosteum,  and  the  sclerotic. 

6.  The  posterior  ethmoidal  artery  sometimes 
arises  from  the  lachrymal  or  supra-orbital ;  it 
passes  inwards  between  the  superior  oblique 
and  rectus  internus,   and  enters  the  foramen 
orbitarium  internum  posterius,  giving  branches 
to  the  anterior  ethmoidal  cells  and  their  lining 
membrane ;  it  then  enters  the  cranium,  where 
it  is  distributed  to  the  dura  mater,  over  the 
cribriform  plate,  through  the  holes  of  which  it 
sends  some   branches  to   the   pituitary  mem- 
brane,   and    anastomoses    with    the    anterior 
ethmoidal. 

The  anterior  ethmoidal  artery  is  given  off 
by  the  ophthalmic  towards  the  anterior  part  of 
the  orbit ;  it  passes  through  the  foramen  orbi- 
tarium internum  anterius  with  the  nasal  branch 
of  the  ophthalmic  nerve,  and  after  giving 
branches  to  the  interior  of  the  frontal  sinus  and 
anterior  ethmoidal  cells,  it  enters  the  cranium 
and  divides  into  many  branches,  some  of  which 
go  to  the  dura  mater,  and  others  descend  into 
the  nasal  fossae  by  the  holes  in  the  cribriform 
plate  of  the  ethmoid  bone,  and  are  distributed 
to  the  pituitary  membrane. 

7.  The  palpebral  arteries  sometimes  arise  by 
a  common  trunk  and  sometimes  separately. 

The  superior  palpebral  arises  a  little  further 
forward  than  the  inferior ;  they  are  distributed 


to  the  conjunctiva  and  to  the  eyelids,  in  which 
they  spread  out  their  branches  between  the 
skin  and  the  orbicularis  muscle.  They  princi- 
pally divide  each  into  two  branches,  one  of 
which  runs  along  the  tarsal  margin,  supplying 
the  tarsal  cartilage,  Meibomian  glands,  and  con- 
junctiva, and  the  other  nearer  to  the  base  of 
the  eyelids  in  an  oblique  course  from  within 
outwards. 

The  superior  palpebral  anastomoses  with 
the  lachrymal,  superciliary,  frontal,  and  an- 
terior branch  of  the  temporal. 

The  inferior  palpebral  anastomoses  with  the 
infra-orbital,  the  lachrymal,  and  nasal. 

After  the  ophthalmic  artery  has  given  off 
the  palpebral,  it  divides  into  two  branches,  one 
of  which  is  the  frontal  and  the  other  the  nasal. 

8.  The  frontal  artery  is  usually  the  smaller 
of  the  two ;  it  passes  out  of  the  orbit  at  the 
superior  and  internal  part  of  the  base  of  that 
cavity,   and  divides  almost  immediately  into 
two  or  three  branches,  which  ascend  on  the 
forehead,  over  which  they  ramify,  and  are  dis- 
tributed to  the  orbicularis,   corrugator  super- 
cilii,    pyramidalis    nasi,    and   occipito-frontalis 
muscles,  to  the  periosteum  and  common  inte- 
guments :  these  anastomose  with  the  opposite 
artery,  the  superciliary,  and  the  temporal. 

9.  The  nasal  artery  varies  in  size,    being 
sometimes  only  a  very  trifling  branch,  which 
terminates  at  the  root  of  the  nose ;  sometimes 
its  size  is  considerable,  as,  when  it  descends 
very  low,  contributing  with  the  lateral  nasal 
branch  of  the  facial  to  supply  the  place  of  the 
dorsal  artery  of  the  nose,  in  which  case  it  ex- 
tends to  the  lower  part  of  that  organ;  it  always 
anastomoses  with  the  facial  and  inferior  pal- 
pebral, and  gives  branches  to  the  integuments, 
cartilages,  and  bones  of  the  nose,  to  the  la- 
chrymal sac,  to  the  corrugator  supercilii,  and 
the  internal  part  of  the  orbicularis  palpebrarum. 

The  internal  carotid,  after  it  has  furnished 
the  ophthalmic  artery,  is  distributed  entirely  to 
the  brain,  especially  to  its  anterior  part,  the 
posterior  part  of  that  organ  receiving  its  prin- 
cipal supply  of  blood  from  the  vertebral. 
Having  pierced  the  dura  mater  at  the  external 
side  of  the  anterior  clinoid  process,  and  ex- 
ternal to  the  optic  nerve,  the  internal  carotid 
artery  gives  several  minute  branches  to  this 
nerve,  to  the  pituitary  gland,  the  infundibulum, 
and  anterior  part  of  the  brain;  shortly  after 
this  it  gives  a  branch  which  is  very  variable  in 
size,  frequently  differing  in  this  respect  on 
opposite  sides  in  the  same  subject;  this  is  the 
lateral  or  posterior  communicating  branch  of 
Willis,  which  passes  backwards  and  a  little 
inwards,  external  to  the  commissure  of  the 
optic  nerves,  infundibulum,  tuber  cinereum, 
and  the  corpora  mammillaria,  and  joins  the 
posterior  artery  of  the  cerebrum,  which  is  a 
branch  of  the  basilar :  the  motor  oculi  lies  ex- 
ternal to  it.  In  its  course  it  gives  small 
branches  to  the  corpora  mammillaria,  the  crus 
cerebri,  the  optic  nerves,  and  the  choroid 
plexus. 

After  having  given  off  the  communicating 
artery,  the  carotid  sends  a  branch  to  the  choroid 
plexus,  the  arteria  choroidea  ;  the  artery  passes 


CAROTID  ARTERY. 


493 


backwards  and  outwards,  enters  the  tractus 
opticus,  supplies  the  pia  mater  of  the  middle 
lobe  of  the  brain  and  the  optic  thalamus,  and, 
entering  the  inferior  cornu  of  the  lateral  ven- 
tricle, spreads  out  its  branches  in  the  choroid 
plexus. 

After  having  given  off  the  choroid  artery,  the 
internal  carotid  divides  always  at  an  obtuse 
angle,  and  at  the  internal  extremity  of  the  fis- 
sure of  Sylvius,  into  two  branches,  the  an- 
terior and  the  middle  cerebral,  of  which  the 
latter  is  much  the  larger  vessel :  sometimes 
the  lateral  communicating  artery  arises  at  the 
place  of  this  division,  and  forms  with  these 
branches  a  sort  of  tripod. 

The  anterior  cerebri,  also  called  the  artery 
of  the  corpus  callosum,  is  always  smaller  than 
the  media  cerebri ;  it  passes  upwards,  forwards, 
and  inwards  to  the  fissure  which  separates  the 
anterior  lobes  of  the  cerebrum,  passing  over 
the  optic  nerves,  and  inferior  to  the  internal 
origin  of  the  olfactory:  on  entering  the  above- 
mentioned  fissure,  it  approaches  closely  to  the 
corresponding  branch  of  the  opposite  side, 
with  which  it  communicates  by  a  large  and 
very  short  transverse  branch,  called  the  anterior 
communicating  artery,  by  which  the  circle  of 
Willis  is  completed  anteriorly :  sometimes 
this  branch  is  double,  and  occasionally  we  find 
it  partially  double,  in  consequence  of  a  forking 
of  one  of  its  extremities ;  its  place  is  sometimes 
supplied  by  a  fasciculus  of  small  branches  ;  it 
gives  off,  especially  when  it  is  unusually  long, 
a  number  of  small  twigs,  which  pass  upwards 
and  backwards  to  the  septum  lucidum,  ibrnix, 
and  corpus  callosum. 

From  the  place  of  this  communication  the 
trunk  of  the  anterior  cerebri  passes  forwards 
under  the  corpus  callosum,  giving  off  consi- 
derable branches  to  the  inferior  and  internal 
part  of  the  anterior  lobe  of  the  cerebrum ;  it 
then  turns  round  to  the  anterior  extremity  of 
the  corpus  callosum,  mounts  up  on  the  internal 
surface  of  the  hemisphere  of  the  cerebrum, 
and  divides  into  many  branches,  the  anterior 
and  superior  of  which  supply  the  convolutions 
on  their  internal  surface,  while  the  posterior 
take  a  lower  course  along  the  upper  sur- 
face of  the  corpus  callosum,  at  the  posterior 
extremity  of  which  they  take  an  ascending 
direction.  All  these  branches  extend  to  the 
superior  surface  of  the  cerebrum,  and  anasto- 
mose with  those  of  the  media  cerebri  and  the 
posterior  cerebri,  which  is  furnished  by  the  ver- 
tebral. 

Besides  these  large  branches  into  which  the 
arteria  callosa  divides  superiorly,  it  gives  off 
from  its  inferior  and  concave  side  a  vast  number 
of  smaller  branches,  which  penetrate  the  corpus 
callosum. 

Sometimes,  instead  of  being  connected  by 
the  communicating  branch,  the  anterior  cerebral 
arteries  of  opposite  sides  unite,  forming  a  single 
trunk,  which  runs  forward  for  some  little  dis- 
tance, and  then  divides  into  a  right  and  left 
branch ;  this  junction  is  the  more  remarkable, 
on  account  of  its  analogy  to  the  union  of  the 
two  vertebral  arteries  in  forming  the  single 
trunk  of  the  basilar  on  the  median  line. 


The  media  cerebri,  from  its  greater  size  com- 
pared with  the  anterior  branch,  appears,  as  it 
were,  the  continuation  of  the  trunk  of  the 
carotid ;  it  passes  outwards  and  backwards,  in 
the  fissure  of  Sylvius,  and  divides  into  two 
branches,  the  subdivisions  of  both  of  which 
are  distributed  over  the  pia  mater  of  the  anterior 
and  middle  lobes  of  the  brain,  anastomosing 
in  front  with  the  anterior  cerebri,  and  behind 
with  the  posterior  cerebri  from  the  basilar: 
this  artery  at  first  gives  branches  at  the  base  of 
the  brain  to  the  pia  mater  on  the  crus  cerebri ; 
one  of  these,  larger  than  the  others,  enters  the 
inferior  cornu  of  the  lateral  ventricle,  where  it 
is  lost  in  the  choroid  plexus. 

The  anterior  and  middle  cerebral  arteries  are 
not  always  similarly  disposed  on  opposite 
sides ;  it  not  unfrequently  happens,  as  Haller 
has  remarked,  that  the  two  large  trunks  of  the 
middle  cerebral  arteries  are  given  off  by  the 
right  carotid,  and  the  two  anterior  from  the 
left  carotid,  while  the  three  others  come  from 
the  right:  considering  these  anomalies  with 
that  of  the  union  of  the  two  cerebral  already 
mentioned,  we  here  find  a  very  remarkable 
repetition  of  many  of  the  varieties  exhibited  by 
the  mode  in  which  the  trunks  that  spring  from 
the  arch  of  the  aorta  take  their  origin. 

For  the  BIBLIOGRAPHY,  see  that  of  ANATOMY 
(INTRODUCTION),  and  of  ARTERY. 

(J.  Hart.) 

The  following  observations  are  to  be  regarded 
as  supplemental  to  the  preceding  article. 

There  is  no  fact  more  worthy  of  the  atten- 
tion of  the  practical  surgeon,  as  regards  the 
anatomical  history  of  the  carotid  artery,  than 
the  free  anastomosis  which  exists  between  the 
external  and  internal  carotids  of  both  sides  at 
nearly  all  the  stages  of  their  course.  This  is 
especially  the  case  with  the  external  carotid 
arteries  which  anastomose  at  numerous  short 
intervals  from  their  origin  to  their  termination, 
where  they  likewise  communicate  with  some 
small  ramifications  of  the  internal  carotids. 
Nor  is  the  communication  between  the  internal 
carotids  less  free,  although  it  is  less  frequent : 
this  communication  is  formed  within  the  cra- 
nium at  the  anterior  segment  of  the  circle  of 
Willis.  Moreover,  by  means  of  the  posterior 
communicating  artery  the  internal  carotid  anas- 
tomoses with  the  posterior  cerebral,  and  there- 
by with  the  subclavian,  through  the  medium  of 
the  vertebral  artery.  And  farther,  by  the  anas- 
tomoses of  the  superior  thyroid  artery  with  the 
inferior,  and  of  the  occipital  with  the  cervicalis 
ascendens,  profunda,  and  vertebral,  a  commu- 
nication is  established  between  the  external 
carotid  artery  and  the  subclavian. 

From  the  knowledge  of  the  communication 
thus  existing  between  these  several  portions  of 
the  arterial  system  of  the  neck  and  head,  we 
may  deduce  some  very  useful  inferences. 

1.  It  is  evident  that  the  carotids  of  both 
sides  may  be  injected  by  even  a  coarse  injec- 
tion, from  a  pipe  introduced  into  the  artery  of 
one  side.  This  is  a  fact  well  known  to  every 
practical  anatomist. 


494 


CAROTID  ARTERY. 


2.  With  the  knowledge  of  this  freedom  of 
communication  between  the  carotids,  no  sur- 
geon will  look  for  uniform  success  after  the 
application  of  a  ligature,  in  cases  of  wounds 
of  either  carotid  or  of  one  of  its  branches, 
if  the  ligature  be  applied  only  below  the  situ- 
ation of  the  wound.     Nevertheless,  experience 
tells  us,  that  such  a  plan  of  treatment  has  been 
successful  in  several  instances ;  and  it  is  wor- 
thy of  notice  that  in  almost  all  the  successful 
cases  the  primitive  carotid  was  tied  very  shortly 
after  the  infliction  of  the  wound,  at  a  time 
when  the  collateral  branches  could  not  have 
become  sufficiently  enlarged  to  admit  of  the 
full  circulation  in  them ;    while,  on  the  other 
hand,  in  two  unsuccessful  cases,  the  primitive 
carotid  was  not  tied  for  some  days  after  the 
receipt  of  the  wound,  and  secondary  hemor- 
rhage ensued  in  each  case. 

3.  The  free  anastomosis  of  the  two  internal 
carotids  with   each  other  and  with  the  sub- 
clavians  through  the  vertebrals  within  the  cra- 
nium, sufficiently  evinces  that  the  circulation 
of  the  brain  after  the  obliteration   of  either 
carotid,  by  ligature  or  otherwise,  may  be  easily 
maintained  ;  and  experience  fully  confirms  this 
inference  from  anatomy.    That  a  disturbance 
of  the  cerebral  circulation  does  occur  occa- 
sionally after  the  operation  of  tying  the  carotid 
is  fully  proved  ;  but  it  would  appear  that  it  is 
an   occurrence  much  more  rare  than  might, 
a  priori,  be  expected.     Of  seventy  cases,  col- 
lected by  Berard,*  in  which  this  operation  was 
performed,    symptoms    arising    from  cerebral 
affection  appeared  only  in  a  very  few,  and  in 
two  only  of  these  instances  the  patients  died 
from  the  effect  produced  upon  the  cerebral  cir- 
culation.    One  of  these  cases  occurred  in  the 
practice  of  Mr.  Aston  Key ;    the  patient  fell 
into  a  deep  sleep  after  a  severe  fit  of  coughing, 
and  died  shortly  afterwards  without  awaking. 
On  examination  it  was  found  that  the  carotid 
of  the  opposite  side  was  obliterated  by  a  co- 
agulum  nearly  as  low  as  its  origin  from  the 
aorta,    so   that  the  cerebral  circulation  could 
only  have  been  maintained  by  the  two  vertebral 
arteries,  which  in  this  case  were  smaller  than 
usual.     In  the  second  case,  which  was  ope- 
rated on  by  Langenbeck,f  immediately  after 
the  application  of  the  ligature  the  patient  be- 
came motionless,  with    closed   eyes,   without 
speaking,  except  when  addressed  several  times 
in  succession;  he  sank  gradually,  and  died  in 
thirty-four  hours  after  the  operation  .J 

In  three  of  the  cases  collected  by  Berard, 
some  disturbance  or  indistinctness  of  vision, 
on  the  same  side  as  that  on  which  the  artery 
was  tied,  followed  the  operation;  in  one  of 
these  the  impairment  of  sight  was  accompanied 
by  syncope,  and  a  sensation  of  cold  affecting 

*  Diet,  de  Medecine,  art.  Carottde. 

f  Arch.  Gen.  de  Med.  t.  xix.  p.  118. 

t  Dr.  Mussey,  of  New  Hampshire,  in  America, 
has  recorded  a  case  in  which  he  tied  both  primitive 
carotids  within  twelve  days  of  each  other,  and 
without  any  untoward  result.  The  reader  will  find 
the  case  quoted  at  length  in  Mr.  Guthrie's  valuable 
work  on  the  Diseases  and  Injuries  of  Arteries, 
p.  350. 


the  whole  of  that  side  of  the  face ;  in  a  second, 
related  by  Mr.  Mayo,  the  impaired  vision  was 
only  on  the  right  side,  the  carotid  of  which 
side  had  been  tied,  and  the  sense  was  perfectly 
restored  in  a  few  hours.  In  the  third  case  one 
eye  was  completely  deprived  of  sight,  and  the 
sense  of  hearing  greatly  weakened  in  the  ear 
of  the  same  side.  Berard  remarks  that  the  loss 
or  impairment  of  vision  on  one  side  is  un- 
favourable to  the  opinion  that  such  an  occur- 
rence is  to  be  attributed  to  disturbed  cerebral 
circulation ;  it  is  sufficiently  accounted  for  by 
the  fact  that  there  is  a  considerable  diminution 
in  the  quantity  of  blood  sent  to  the  eye ;  for 
that  organ  is  supplied  by  a  direct  branch  of  the 
internal  carotid,  viz.  the  ophthalmic,  which 
anastomoses  at  its  termination  with  several  of 
the  terminal  branches  of  the  arteries  of  the 
face ;  and  it  is  not  improbable  that  in  the  cases 
above  referred  to,  the  branches  which  form  this 
anastomosis,  as  well  as  those  forming  the  circle 
of  Willis  at  the  base  of  the  brain,  were  much 
smaller  than  usual. 

In  other  cases  hetniplegia,  more  or  less  ge- 
neral and  perfect,  followed  the  operations  after 
a  longer  or  shorter  period.  In  a  case  related 
by  Magendie,  that  of  a  young  girl,  in  whom 
the  left  carotid  was  tied,  there  appeared  on  the 
sixth  day  paralysis  of  the  right  arm,  of  the 
pharynx  and  larynx,  and  numbness  of  the  right 
lower  extremity.  The  paralysis  gradually  di- 
minished, but  the  intellect  was  so  far  impaired 
that  the  patient  lost  the  power  of  reading.* 
In  Sir  A.  Cooper's  first  case,  the  right  arm  and 
leg  were  deprived  of  sensation  and  in  part  of 
motion  on  the  seventh  day  after  the  operation ; 
and  a  man,  in  whom  Mr.  Vincent  tied  the  right 
carotid  for  aneurism,  was  attacked  with  com- 
plete hemiplegia  of  the  left  side  in  half  an  hour 
after  the  operation,  and  continued  in  that  state 
till  his  death  on  the  seventh  day.  It  is  re- 
markable that,  in  all  these  cases,  the  paralysis 
was  situated  on  the  side  opposite  to  that  on 
which  the  artery  was  tied ;  a  fact  which  alone 
would  indicate  that  the  cause  of  the  paralysis 
was  seated  in  the  brain. 

Aneurisms  do  not  occur  so  frequently  in  the 
carotid  arteries  as  in  the  aorta  or  in  the  large 
arteries  of  the  extremities.  They  are  most 
frequently  found  situated  at  the  bifurcation  of 
the  common  carotid,  where  also  calcareous 
and  atheromatous  deposits  are  very  often  met 
with.  In  the  lower  part  of  the  common  ca- 
rotid an  aneurism  is,  of  course,  a  more  for- 
midable disease  than  if  it  were  situated  high 
up,  in  consequence  of  the  impossibility  of 
applying  a  ligature  between  the  artery  and  the 
heart.  Sometimes  an  aneurism  of  the  aorta 
projects  upwards  into  the  neck,  compressing 
and  obliterating  the  carotid,  and  simulating  all 
the  characters  of  aneurism  of  its  lower  portion. 
I  am  not  aware  that  there  is  on  record  any 
instance  of  aneurism  of  the  internal  carotid 
artery  in  its  cervical  portion,  although  our  mu- 
seums are  not  without  specimens  of  aneurismal 
dilatations  of  it  after  it  has  entered  the  cranium, 
and  as  it  lies  by  the  side  of  the  sella  Turcica. 

*  Journal  de  Physiol.  April,  1827. 


CARTILAGE. 


495 


We  sometimes  find  the  cervical  portion  of  this 
artery  in  a  tortuous  state,  but  we  rarely  see  in 
it  those  atheromatous  and  earthy  deposits  which 
are  met  with  in  other  parts  of  it. 

In  the  dead  body  there  is  no  difficulty  in 
exposing  the  common  carotid  artery  in  any 
part  of  its  course,  but  during  life  much  em- 
barrassment is  occasioned  by  the  alternate  di- 
latation and  collapse  of  the  internal  jugular 
vein,  corresponding  with  expiration  and  inspi- 
ration, and  sometimes  by  some  small  veins 
which  lie  in  front  of  the  artery.  It  may  be 
cut  down  upon  either  above  or  below  the  omo- 
hyoid  muscle,  but  in  the  former  situation  the 
superficial  position  of  the  vessel  and  the  less 
complexity  of  its  relations  render  it  more  easy 
to  be  got  at.  In  both  situations  the  anterior 
margin  of  the  sternomastoid  muscle  forms  a 
useful  guide  to  the  artery ;  but  much  more 
careful  dissection  is  required  when  the 
operation  is  done  in  the  region  below  the 
omohyoid  muscle.  Here  great  care  is  de- 
manded in  dissecting  back  the  sternomastoid 
muscle,  and  in  drawing  the  sternothyroid 
inwards;  the  thyroid  body  and,  on  the  left, 
the  oesophagus  must  be  avoided,  and  in  pas- 
sing the  ligature  round  the  artery,  the  ope- 
rator must  take  care  to  avoid  not  only  the  vein 
and  par  vagum  but  also  the  inferior  thyroid 
artery,  the  recurrent  and  sympathetic  nerves 
and  the  cardiac  branches  of  the  latter,  and  on 
the  left  side  the  thoracic  duct.  As  anomalies 
in  the  distribution  of  some  of  the  arteries  in 
the  neck  are  occasionally  met  with,  the  surgeon 
should  be  on  his  guard  against  such  an  occur- 
rence, especially  in  operating  in  the  low  region 
where  they  are  most  likely  to  be  met  with.  Two 
arteries  may  be  found  here  occupying  pretty 
nearly  the  situation  of  the  carotid  artery.  One 
of  these  will  be  the  carotid  itself,  the  other  the 
vertebral,  which  sometimes  passes  high  up  in  the 
neck  in  front  of  the  rectus  capitus  anticus  muscle, 
before  it  enters  the  canal  in  the  transverse  pro- 
cesses of  the  cervical  vertebrae.  In  a  case  related 
by  Mr.  Allan  Burns,*  the  vertebral  artery  en- 
tered this  canal  only  a  few  lines  below  the  bifur- 
cation of  the  carotid,  and  in  its  passage  up  the 
neck,  parallel  to  and  behind  the  carotid,  it  was 
separated  from  that  vessel  only  by  its  sheath. 
A  low  bifurcation  of  the  carotid  artery  would  be 
equally  likely  to  occasion  embarrassment;  and 
the  possibility  of  such  a  condition  of  the  cer- 
vical vessels  as  well  as  of  the  anomalous  course 
of  the  vertebral  artery  before  alluded  to  are 
strong  arguments  in  favour  of  the  recommenda- 
tion of  Mr.  Burns,  that,  "  when  the  surgeon 
has  reached  the  sheath  of  the  vessels  he  ought 
uniformly,  before  opening  it,  to  press  the  carotid 
between  the  finger  and  thumb.  If  the  pulsa- 
tion of  the  tumour  be  not  in  this  way  con- 
trolled, he  will  do  well  to  pause  before  he  pass 
a  ligature  round  that  vessel."f  In  fine  we 
sometimes  find  the  inferior  thyroid  artery  cros- 
sing in  front  of  the  common  carotid  in  the 
inferior  region. 


*    Surgical  Anatomy  of   the  Head   and  Neck, 
p.  170. 
t  Loc.  cit. 


It  is  very  easy  in  the  dead  body  to  find  the 
primitive  carotid  low  down  in  the  neck  by 
cutting  in  the  cellular  interval  between  the 
clavicular  and  sternal  po>-tions  of  the  sterno- 
mastoid muscle,  but  it  is  not  so  easy  to  pass 
a  ligature  round  it;  and  this  difficulty  is  greatly 
magnified  in  the  living  subject,  in  consequence 
of  the  necessarily  limited  space  in  which  the 
operator  has  to  work;  the  difficulty  too  is 
greatly  increased  by  the  contractions  of  the 
sternomastoid  muscle. 

To  expose  the  external  carotid  artery  shortly 
after  its  origin,  it  is  only  requisite  to  follow  the 
same  steps  as  are  necessary  for  cutting  down 
on  the  common  carotid  above  the  omohyoid 
muscle.  It  is  in  general  advisable  to  apply 
the  ligature  below  the  point  at  which  the  di- 
gastric muscle  crosses  the  artery  and  below  the 
origin  of  the  superior  thyroid.  Some  embar- 
rassment is  likely  to  result  from  the  plexus 
of  veins  which  in  this  region  often  lies  in  front 
and  on  the  sides  of  the  artery.  A  ligature, 
however,  may  be  passed  round  this  artery 
above  the  digastric  muscle,  but  it  will  be  re- 
quisite that  the  external  incision  shall  com- 
mence higher  up.  The  needle  must  be  passed 
between  the  parotid  gland  and  the  digastric 
tendon,  the  distances  between  these  parts  hav- 
ing been  previously  increased  by  drawing  down 
the  tendon  of  the  muscle. 

(R.  B.  Todd.) 

CARTILAGE  (Lat.  cartilago,  quasi  car- 
nilago ;  Gr.p^oy^o?;  Fr.  cartilage;  Germ.Xnor- 
pel ;  Ital.  cartilagine}  is  a  firm  elastic  sub- 
stance, of  pearly  whiteness,  and  uniform  or 
homogeneous  in  its  appearance.  It  bears  a 
considerable  analogy  to  bone,  and  is  to  be 
found  in  situations  where  less  rigidity  and  more 
elasticity  are  required  than  the  osseous  system 
presents. 

Several  tissues,  differing  a  good  deal  from 
each  other,  were  formerly  comprehended  under 
this  term.  These  have  been  variously  classified 
by  modern  anatomists ;  but  the  division  of  them 
into  cartilages  and  jibro-cartilages,  proposed  by 
Bichat,*  is  that  which  is  now  generally  adopted. 
Although  Bichat  was  happy  in  the  choice  of 
names  for  these  tissues,  yet,  in  arranging  the 
individual  pieces  under  the  two  heads  just 
mentioned,  he  has  not  been  found  quite  correct. 
Some  of  the  true  cartilages  are  placed  by  him 
amongst  the  fibre-cartilages,  an  error  which 
Meckel  perceived  and  rectified  .f 

Cartilages  may  be  divided  into  the  temporary, 
the  permanent,  and  the  accidental. 

A.  The  TEMPORARY  cartilages  are  substitutes 
for  bone  in  the  earlier  periods  of  life,  and  after 
a  certain  time  become  ossified.     We  find  them 
at  birth  forming  the  extremities  and  larger  emi- 
nences of  long  bones,  a  great  part  of  the  short 
bones,  and   the   margins  of  the   broad  ones. 
These  gradually  disappear,  and  at  puberty  cease 
to  exist.      It  is  unnecessary  to  say  more  of 
them  here.     (See  OSTEOGENY.) 

B.  PERMANENT  cartilages  are  met  with  under 

*  Anatomie  Generate,  torn.  iii.     Par.  1812. 
t  Manuel  d'Anatomie,  torn.  i.     Par.  1825. 


496 


CARTILAGE. 


two  forms  :  1,  the  articular,  attached  to  bone, 
and  entering  into  the  formation  of  joints ;  2,  the 
non-articular,  forming  canals  more  or  less  per- 
fectly. 

I.  The  articular  cartilages  are  called  diar- 
throdial,  abducent,  or   of   incrustation,   when 
they  belong    to    the   moveable    articulations; 
synarthrodial  when  connected  with  those  very 
limited  in  their  motions,  or  the  immoveable 
articulations  of  some  authors.      We  think  it 
unnecessary   to  do   more   than  refer  to   these 
cartilages  here,  as  their  characters  will  be  found 
fully  described  in  the  article  ARTICULATION. 

II.  The  non-articular  cartilages  are  usually 
much  more  flexible  than  the  articular.    In  some 
cases  they  are  attached  to  bones,  and  lengthen 
them  out,  as  the  preceding  class.     Of  this  we 
see  examples  in  the  nose,  the  auditory  canal, 
and  the  Eustachian  tube.     In  other  cases  they 
are    insulated,   forming   the  basis    of  distinct 
organs,  as  the  larynx,  the  trachea,  the  eyelids. 
All   the   cartilages  of  this  class  have  a  well- 
marked  perichondrium.*      Some  of  them,  as 
the  epiglottis,  the  tarsal  cartilages,  and  those  of 
the  alae  nasi,  are  so  thin,  so  flexible,  and  assume 
so  much  of  a  fibrous  appearance  from  their 
perichondrium,  that  Bichat  placed  them  amongst 
the  fibre-cartilages ;  but  these  last  never  have 
perichondrium,    and   their    fibrous   texture   is 
distinctly  independent  of  their  investment,  as 
is  easily  seen  without  any  preparation.     (See 

FlBRO-CARTILAGE.) 

The  structure  of  non-articular  cartilage,  like 
the  other  forms,  may,  by  protracted  maceration, 
be  shown  to  be  fibrous ;  but  the  arrangement 
of  its  fibres  is  different ;  they  interlace  a  good 
deal  more. 

The  physical  properties  of  cartilages  are  such 
as  to  fit  them  admirably  for  the  functions  which 
they  have  to  perform.  They  are  solid,  resisting, 
and  incapable  of  extension,  that  they  may  be 
able  to  preserve  the  form  of  certain  parts  as 
effectually  as  bone;  and  they  are  flexible  and 
elastic,  to  enable  them  to  yield  in  some  degree, 
and  immediately  to  resume  their  original  shape. 

Elasticity  is  the  property  most  essential  to 
them,  and  on  this  their  usefulness  mainly  de- 
pends. Its  existence  is  easily  demonstrated. 
If  the  blade  of  a  knife  be  pressed  into  a  diar- 
throdial  cartilage,  the  reaction  of  the  displaced 
fibres  expels  it  with  force ;  and  a  piece  of  any 
cartilage,  if  bent  between  the  fingers,  returns 
with  a  spring  to  its  former  shape.  The  elastic 
fibres  of  diarthrodial  cartilage  are  so  placed  as 
to  receive  impressions  on  their  extremities ; 
they  yield  a  little  to  force,  and  only  a  little, 
else  the  ligaments  would  be  too  much  relaxed ; 
but  they  yield  enough  to  let  the  opposite  sur- 
faces accommodate  themselves  to  each  other, 
and  to  deaden  the  shocks  which  would  other- 
wise have  an  injurious  effect  on  the  nervous 
centre.  In  fact,  these  articular  cartilages  serve 
as  a  series  of  springs  between  the  ground  and 
the  delicate  organs  which  they  support.  The 


*  If  we  except  the  capsule  of  the  lens  and  the 
posterior  layer  of  the  cornea,  supposing  these 
structures  to  belong  to  the  cartilaginous  system. 
See  EYE. 


elasticity  of  the  costal  cartilages  is  obvious  and 
essential.  They  are  subject  to  torsion  in  the 
act  of  inspiration,  and  by  their  reaction  become 
an  important  agent  in  expiration. 

Differences  depending  upon  age. — Cartilages 
are  soft,  transparent,  and  like  jelly  in  the  very 
young  foetus.  Gradually,  as  the  individual 
advances  to  maturity,  they  become  opaque, 
white,  firm,  and  elastic ;  and  in  the  adult  these 
qualities  are  in  their  greatest  perfection.  In 
old  age  they  lose  again  their  elasticity  and 
flexibility ;  a  yellowish  colour  takes  the  place  of 
their  beautiful  pearly  white;  they  become  dry 
and  brittle,  and  shew  a  great  tendency  to  ossify. 

Organization. —  Cartilage  appears  at  first 
sight  to  be  perfectly  homogeneous  throughout, 
like  a  concrete  jelly,  not  shewing  any  traces  of 
organization,  nor  exhibiting  the  least  appear- 
ance of  vessels.  But,  as  an  attentive  examina- 
tion proved  it  to  be  fibrous,  so  we  shall  be  able 
to  satisfy  ourselves  that  it  possesses  an  organi- 
zation similar  to  other  parts  of  the  living  sys- 
tem. In  healthy  cartilage,  it  is  true,  no  red 
vessels  can  be  demonstrated,  neither  can  the 
finest  injection  be  made  to  penetrate  it,  nor 
will  madder  used  in  food  colour  it.  But  dis- 
ease sometimes  shows  red  vessels  ramifying 
through  its  substance  ;*  and  several  other  phe- 
nomena lead  us  to  the  conviction  that  it  is  at 
all  times  permeated  with  vessels,  though  they 
may  be  too  fine  to  admit  the  red  globules.  For 
instance,  we  find  cartilage  assume  a  yellow 
tinge  in  jaundice.  If  we  slice  off  a  bit,  the  dry 
surface  is  soon  moistened  with  a  serous  fluid, 
which,  doubtless,  comes  from  its  colourless 
vessels.  Exposed  cartilages  have  been  known 
to  granulate,  which  implies  the  existence  of 
vessels,  and  perhaps  of  cellular  substance.  And 
we  know  that  in  the  old  and  laborious  there  is 
often  not  the  least  sign  of  wear,  although  the 
enamel  of  the  teeth  be  quite  worn  away.  Where 
a  perichondrium  is  present,  we  may  suppose 
the  vessels  first  ramify  in  it  before  they  enter 
the  cartilage.  Dr.  William  Hunter  describes 
the  arrangement  of  the  vessels  which  supply 
diarthrodial  cartilage  to  be  very  peculiar.  He 
says,  "  All  around  the  neck  of  the  bone  there 
are  a  great  number  of  arteries  and  veins  which 
ramify  into  smaller  branches,  and  communicate 
with  one  another  by  frequent  anastomoses,  like 
those  of  the  mesentery.  This  might  be  called 
the  circulus  articuli  vasculosus,  the  vascular 
border  of  the  joint.  The  small  branches  divide 
into  still  smaller  ones  upon  the  adjoining  sur- 
face, in  their  progress  towards  the  centre  of  the 
cartilage.  We  are  seldom  able  to  trace  them 
into  its  substance,  because  they  terminate  ab- 
ruptly at  the  edge  of  the  cartilage,  like  the 
vessels  of  the  albuginea  oculi  when  they  come 
to  the  cornea."f 

It  does  not  appear  that  nerves  or  absorbents 
have  ever  been  traced  into  cartilages  ;  but  the 
phenomena  of  disease,  pain,  ulceration,  &c., 
convince  us  that  they  are  supplied  with  both. 
Even  in  their  healthy  condition,  though  their 


*  JBrodie  on   Diseases  of  Joints,  p.   183,  third 
edition. 

t  Phil.  Trans.  1743. 


CARTILAGE. 


497 


animal  sensibility  is  exceedingly  low,  scarcely 
perceptible,  yet  it  probably  does  exist,  and 
will  manifest  itself  whenever  any  cause  is 
operating  upon  them  which  might  destroy  their 
texture.  We  may,  indeed,  cut  an  exposed  car- 
tilage without  pain,  and  the  violent  pressure  it 
undergoes  in  a  sound  joint  is  unheeded.  But 
the  former  is  a  kind  of  injury  from  which  car- 
tilage may  be  said  to  be  totally  exempted,  and 
the  latter  is  that  for  which  it  is  peculiarly 
adapted.  In  either  case  sensibility  would  be 
useless  or  inconvenient.  Let  but  a  foreign  body 
however  get  into  a  joint,  between  its  cartilages, 
such  as  might  disorganize  them,  and  then  an 
alarm  is  set  up  too  great  to  be  attributed  to  the 
synovial  membrane  alone,  and  depending,  we 
may  suppose,  in  part  at  least,  on  the  cartilage 
itself. 

C.  ACCIDENTAL  CARTILAGE. — By  this  name 
we  designate  the  cartilaginous  concretions  which 
are  occasionally  found  in  situations  where  they 
do  not  ordinarily  exist.  They  present  them- 
selves in  several  organs,  under  various  forms, 
and  in  different  stages  of  development.  Laennec 
divides  them  into  perfect  and  imperfect  ;*  but 
it  is  not  easy  to  point  out  any  line  of  distinction 
between  these  two  classes;  they  differ  only  in 
degree,  the  one  passing  gradually  into  the  other 
as  its  development  becomes  more  complete. 
We  rarely,  indeed,  meet  with  accidental  car- 
tilage which  deserves  to  be  called  perfect ;  in 
one  part  it  is  fibrous,  or  of  a  dense  cellular 
nature,  in  another  it  is  cartilaginous,  while  a 
third  portion  of  the  same  piece  is  passing  into 
the  osseous  state. 

The  forms  and  situations  in  which  they 
occur,  will  permit  an  arrangement  of  them 
under  three  heads  : — 

1.  The  insulated  or  loose  cartilages,  which  are 
found  either  (a)  in  joints  or  (6)  in  serous  sacs. 

a.  Those  of  the  joints  are  rounded  or  ovoid, 
usually  flattened,  sometimes  lobulated,  always 
smooth,  polished,  and  lubricated  with  synovia, 
frequently  osseous  in  their  centre.  They  vary 
in  magnitude  from  the  size  of  a  mustard-seed 
to  that  of  an  almond ;  and  in  one  instance  Mr. 
S.  Cooper  found  in  the  knee  a  concretion  of 
this  kind,  which  was  as  large  as  the  patella. 
They  also  vary  considerably  in  numbers  ;  Haller 
saw  twenty  in  the  articulations  of  the  lower 
jaw,  and  Morgagni  met  with  twenty-five  in  a 
knee-joint.  Their  most  usual  seat  is  in  the 
knee,  but  they  have  been  found  in  the  hip, 
jaw,  elbow,  and  wrist.  They  are  commonly 
"  loose,"  moving  freely  in  the  cavity,  but  some- 
times connected  to  the  synovial  sac  by  slender 
membranous  attachments. 

With  respect  to  the  origin  of  these  bodies 
various  opinions  have  been  entertained.  Haller 
and  Reimarus  supposed  that  they  were  frag- 
ments of  the  original  cartilage,  accidentally  de- 
tached. Cruveilhier  found  fifteen  of  them  in  a 
hip-joint  some  years  after  it  had  been  injured, 
and  conceived  that  he  saw  an  exact  correspon- 
dence between  them  and  certain  depressions  in 
the  cartilages  of  that  articulation.  Bichat  con- 
jectured they  might  be  altered  portions  of  the 

*  Diet,  des  Sciences  Med. 


synovial  membrane.  According  to  John  Hunter, 
they  may  have  had  their  origin  in  a  coagulum 
of  blood  poured  into  the  joint  from  an  injured 
vessel,  and  there  becoming  organized.  This 
coagulum  would,  he  thought,  assume,  as  in  all 
other  situations,  the  peculiar  organization  of  the 
parts  in  its  immediate  vicinity.  Laennec  and 
Beclard  were  of  opinion  that  they  might  be 
formed  outside  the  synovial  membrane,  and 
push  it  before  them  so  as  to  form  a  pedicle, 
which  in  some  cases  remained,  but  more  gene- 
rally was  ruptured.  This  opinion  Laennec  sup- 
ported by  observations  made  on  similar  sub- 
stances in  serous  sacs,  where  he  traced  them 
through  all  the  degrees  of  their  development, 
from  the  incipient  stage,  in  which  they  formed 
a  slight  projection  behind  the  membrane,  to  the 
period  when  they  became  perfectly  isolated 
bodies.  Sir  Benjamin  Brodie,  whose  authority 
on  this  subject  is  of  so  much  weight,  remarks, 
"  It  is  generally  supposed  that  these  loose 
bodies  have  their  origin  in  coagulated  lymph 
which  has  been  effused  from  inflammation  of 
the  inner  surface  of  the  synovial  membrane, 
and  which  has  afterwards  become  vascular.  In 
the  majority  of  cases,  however,  which  I  have 
met  with,  no  symptoms  of  inflammation  pre- 
ceded their  formation ;  and  hence  it  is  probable 
that,  in  some  instances,  they  are  generated  like 
other  tumours,  in  consequence  of  some  morbid 
action  of  a  different  nature.  They  appear  to  be 
situated  originally  either  on  the  external  sur- 
face, or  in  the  substance,  of  the  synovial  mem- 
brane ;  since,  before  they  have  become  de- 
tached, a  thin  layer  of  this  latter  may  be  traced 
to  be  reflected  over  them."* 

When  inflammation  is  of  long  standing  in  a 
bursa  mucosa,  it  is  not  unusual  to  find  in  it  a 
number  of  loose  bodies,  of  a  flattened  oval 
form,  and  of  a  light  brown  colour,  with  smooth 
surfaces,  resembling  small  melon-seeds  in  ap- 
pearance. There  seems  to  be  no  doubt  that 
these  bodies  have  had  their  origin  in  the  coagu- 
lated lymph  effused  in  the  early  stage  of  the 
disease.f  From  the  resemblance  which  these 
concretions  bear  to  loose  cartilages,  we  might 
infer  that  they  both  have  had  a  similar  origin  ; 
but,  as  there  can  be  no  doubt  that  loose  car- 
tilages sometimes  begin  to  be  formed  outside 
the  synovial  membrane,  we  must  not  conclude 
that  this  is  the  only  mode. 

From  the  evidence  before  us,  therefore,  and 
from  observations  made  on  the  second  species 
of  accidental  cartilage,  to  be  mentioned  by-and- 
bye,  we  are  inclined  to  admit  two  distinct 
sources  from  which  these  loose  cartilages  may 
have  commenced.  One,  a  deposit  in  the  cel- 
lular tissue  outside  the  synovial  membrane;  the 
other  a  deposit  within  this  membrane.  The  ori- 
gin of  both  being  lymph,  which  becomes  cartila- 
ginous, and  often  proceeds  to  an  osseous  state. 

b.  Insulated  cartilages  are  sometimes  found 
in  connexion  with  true  serous  cavities.  They 
are  seldom  larger  than  a  pea,  rounded,  floating, 
or  attached  by  a  pedicle  to  the  inside  of  the 

*    Pathological   and   Surgical    Diseases   of    the 
Joints.     Lond.  1834. 
t  Idem. 

2   K 


498 


CARTILAGE. 


sac,  and,  in  some  instances,  distinctly  outside 
it.  Laennec  often  found  them  between  the 
tunica  vaginalis  testis  and  the  tunica  albuginea, 
and  on  one  occasion  in  the  lining  membrane 
of  the  lateral  ventricles  of  the  brain.  Andral 
saw  three  of  these  bodies  in  the  serous  mem- 
brane of  the  brain ;  one  of  them  floated  loose 
and  unattached  in  the  sac  of  the  arachnoid ; 
the  other  two  were  attached  to  the  choroid 
plexus  by  a  delicate  cellulo-vascular  prolonga- 
tion. He  also  often  found  them  in  the  peri- 
toneum, sometimes  perfectly  isolated,  at  other 
times  appended  to  the  serous  membrane.* 

2.  Accidental  cartilages  of  incrustation, 
occurring  in  plates,  are  very  irregular  in  size 
and  shape.  They  are  most  frequently  found  in 
fibro-serous  membranes,  as  the  dura  mater,  the 
pericardium,  and  the  immediate  coverings  of 
the  testis  and  spleen.  Upon  this  last  viscus 
they  are  seen  more  frequently  than  in  any  other 
situation  whatsoever.  Bichat  supposed  they 
were  altered  portions  of  the  fibrous  membrane, 
having  so  generally  met  with  them  where  the 
latter  existed.  The  subserous  cellular  tissue  is 
the  proper  seat  of  them.  We  often  find  them 
between  the  middle  and  internal  coats  of  ar- 
teries, in  what  may  likewise  be  called  a  sub- 
serous  cellular  tissue.  (See  ARTERY.) 

It  is  exceedingly  rare  to  meet  with  them 
under  mucous  membranes.  Andral  saw  one 
solitary  instance  of  a  true  cartilaginous  mass 
developed  in  the  submucous  cellular  tissue  of 
the  stomach.  The  subcutaneous  cellular  sub- 
stance is  likewise  nearly  exempt  from  them ; 
but  the  same  experienced  pathologist  relates, 
that  one  of  the  lower  extremities  of  a  woman 
who  died  in  La  Charite  in  the  year  1820,  was 
affected  with  elephantiasis ;  underneath  the 
skin,  and  occupying  the  place  of  the  muscles, 
which  were  reduced  to  a  few  pale  fibres,  was 
found  an  enormous  mass  of  condensed  hard 
cellular  tissue,  possessing,  in  many  places,  all 
the  physical  characters  of  cartilage.  In  all 
these  instances  there  is  every  reason  to  believe, 
from  the  closest  examination,  that  the  newly 
formed  substance  is  developed  at  the  expense 
of  the  cellular  tissue  alone,  and  that  neither 
the  fibrous  nor  the  serous  membranes  are  al- 
tered, nor  indeed  any  adjoining  texture.  These 
last  seem  to  be  replaced  by  the  accidental  for- 
mation, but  they  are  only  absorbed  to  make 
room  for  it,  and  not  transformed  into  the  new 
substance.  An  exception  must,  perhaps,  be 
made  in  favour  of  mucous  membrane,  which 
appears  capable  of  undergoing  this  change. 
Laennec  relates  the  case  of  a  child,  in  the 
membranous  portion  of  whose  urethra  he 
found  a  large  calculus.  The  mucous  mem- 
brane of  the  part  presented  several  patches,  of 
the  size  and  thickness  of  a  man's  nail,  which 
appeared  to  him  semi-cartilaginous,  and  were 
incorporated  with,  and  formed  part  of,  the 
mucous  membrane.  In  like  manner  Beclard 
found  the  mucous  membrane  of  the  vagina,  in 
a  case  of  prolapsus  uteri,  studded  over  with 
cartilaginous  spots ;  and  he  observed  a  similar 

*  Andral's  Pathological  Anatomy,   translated  by 
Townsend  and  West. 


appearance  on  the  prepuce  of  an  old  man,  who 
had  had  phymosis  from  the  time  of  birth. 

What  is  the  cause  of  these  formations  ? 
Most  probably  they  have  their  commencement 
in  some  obscure  inflammatory  action.  It  is 
true  we  often  find  them  where  there  is  no  other 
appreciable  lesion  whatsoever,  nor  any  trace  of 
inflammation  in  the  neighbourhood  ;  but,  on 
the  other  hand,  they  seem  to  be  but  a  step  re- 
moved, in  structure,  from  coagulable  lymph, 
and  are  sometimes  imbedded  in  it;  and  the 
irritation  and  consequent  inflammation  pro- 
duced by  foreign  bodies  must  be  allowed  to 
have  occasioned  them  in  the  instances  just 
related  from  Bichat  and  Beclard. 

3.  The  irregular  or  amorphous  masses 
which  we  sometimes  see  in  the  thyroid  gland, 
ovaries,  uterus,  testes,  brain,  liver,  lungs, 
spleen,  kidneys,  and  heart,  are  supposed  to 
differ  from  the  preceding  classes,  not  only  in 
form,  but  in  connexions  and  origin.  They 
appear  to  be  united  by  continuity  of  substance 
with  the  tissues  in  which  they  are  developed, 
and,  in  fact,  to  be  altered  portions  of  them.  But 
it  is  by  no  means  proved  that  cellular  tissue 
may  not,  even  in  these  cases,  be  the  nidus  of 
such  concretions,  and  that  the  organs  have  not 
rather  been  absorbed  to  make  room  for  them, 
than  transformed  into  them. 

In  false  articulations,  old  cicatrices  of  the  liver, 
lungs,  &c.,  we  find  a  substance  resembling  car- 
tilage ;  but  its  description  belongs  to  "  Fibro- 
cartilage"  to  which  we  refer. 

Chemical  composition. — On  this  subject  there 
is  some  difference  among  writers ;  Dr.  Davy* 
found  diarthrodial  cartilage  to  consist  of 

Albumen 44*5 

Water 55-0 

Phosphate  of  lime 00  5 

100-0 

Berzelius  professes  his  ignorance  of  its  com- 
position. Neither  diarthrodial  nor  non-articular 
cartilage  yielded  gelatine,  and  he  doubts  "  whe- 
ther the  mass  which  constitutes  them  be  of  a 
peculiar  nature,  or  similar  to  what  we  find  in 
the  fibrous  coat  of  arteries."  f  By  boiling 
costal  and  synarthrodial  cartilages,  gelatine  is 
developed.  He  looks  on  them  to  be  imperfectly 
developed  bone,  and  to  have  the  composition  of 
its  animal  part,  with  the  addition  of  3-402  per 
cent  of  earth  in  the  false  ribs  of  a  man  of 
twenty. 

In  100  parts  of  this  earth  he  gives  the  fol- 
lowing analysis  from  Frommherz  and  Gugert ; 
Carbonate  of  soda  ....   35-068 

Sulphate  of  soda 24-241 

Muriate  of  soda 8-231 

Phosphate  of  soda  ....     0*925 

Sulphate  of  potass 1-200 

Carbonate  of  lime  ....  18-372 
Phosphate  of  lime  ....  4'056 
Phosphate  of  magnesia  .  6-908 
Oxyde  of  iron,  and  loss .  0-999 

100-000 


*  Monro's  Elements  of  Anatomy,  vol    i. 
f  Traite  de  Chimie,  torn.  vii.     Par.  1833. 


CARTILAGE. 


499 


Pathological  conditions. — Cartilages  are  not 
subject  to  many  diseases.  Inflammation,  ulce- 
ration,  and  ossification  are  almost  the  only  ones 
to  which  they  are  liable ;  and  of  these  the  first 
is  very  indistinctly  marked ;  the  last  scarcely 
deserves  to  be  called  disease.  Cartilages  are 
supposed  to  owe  this  exemption  from  morbid 
actions  to  their  extremely  low  degree  of  vitality. 
Destitute  of  red  vessels,  and  supplied  with  no 
more  nervous  influence  than  is  barely  sufficient 
to  constitute  them  a  part  of  the  living  system, 
they  escape  those  changes  to  which  highly 
organized  parts  are  exposed ;  and,  were  it 
not  for  their  connexion  with  more  delicate 
and  excitable  tissues,  their  exemption  would 
be  still  more  complete.  Some  eminent  pa- 
thologists  have  gone  so  far  as  to  consider 
them  incapable  of  any  morbid  action;  espe- 
cially the  diarthrodial  cartilages.  "  Les  carti- 
lages diarthrodiaux  ne  jouissent  point  de  la 
vie,"  says  Cruveilhier,  who  asserts  that  he 
could  not  excite  disease  in  them  by  any  of  his 
experiments;  and  that  he  saw  them  perfectly 
sound  in  the  midst  of  every  other  diseased 
structure.  Mr.  Key*  also  seems  to  allow  them 
very  little  vitality  in  health,  and  to  consider 
them  very  nearly  passive  in  what  are  called 
their  diseases. 

Inflammation  is  rarely  to  be  met  with.  Its 
characters  are  so  slightly  marked  in  diarthro- 
dial cartilage,  that  we  infer  its  existence,  not  so 
much  from  the  signs  which  are  present,  as  from 
observing  that  ulceration  is  a  common  occur- 
rence— a  state  which  we  suppose  to  have  been 
preceded  by  inflammation.  The  only  marks  of 
inflammation  to  be  seen,  even  when  most  de- 
veloped, are  a  softening  of  the  cartilage,  and  in 
two  instances  detailed  by  Sir  B.  Brodie,  vessels 
injected  with  red  blood  could  be  traced  extend- 
ing from  the  bones  into  the  cartilages  covering 
them.  Severe  pain  accompanies  this  disease; 
but,  as  in  all  the  cases  on  record,  ulceration,  or 
some  other  disease  was  also  present,  it  cannot 
be  determined  how  much  of  the  pain  belonged 
exclusively  to  it.  The  costal  cartilages  are 
subject  to  painful  affections  which  usually 
occur  in  patients  who  have  had  syphilis,  or  to 
whom  mercury  has  been  administered  inju- 
diciously. These  depend  on  inflammation  of 
the  perichondrium.  They  may  terminate  in 
ulceration  or  in  osseous  deposition,  and  have  a 
close  resemblance  to  periostitis. 

Ulceration  of  cartilage  is  a  very  common 
occurrence  in  joints,  but  is  extremely  rare  in 
other  situations.  It  may  be  met  with  at  any 
period  of  life,  or  in  any  articulation,  but  it  is  in 
the  hip  and  knee  we  mo;«t  frequently  find  it, 
and  in  persons  who  have  passed  the  age  of 
puberty  and  are  under  thirty  or  thirty-five. 
A  striking  peculiarity  attends  this  affection, 
namely,  that  the  formation  of  pus  is  by  no 
means  a  constant  accompaniment.  The  form 
and  situations  of  ulcers  in  diarthrodial  cartilages 
are  very  various.  Sometimes  they  are  small  and 
deep  ;  sometimes  very  superficial,  like  an  abra- 
sion— at  one  time  attacking  the  free,  at  another 
the  attached  surface;  and  may  commence  in 

*  Medico-Chimrgical  Transactions.,  vol.  xviii. 


the  centre  or  at  the  circumference.  These  ulcers 
may  be  divided  into  primary  and  secondary,  the 
former  arising  independently  of  any  disease  in 
the  adjoining  tissues,  the  latter  being  preceded 
by  a  morbid  state  of  the  bone  or  synovial 
membrane. 

The  primary  ulcer  commences  towards  the 
centre  of  the  cartilage,  and  always  on  its  free 
surface.  It  is  accompanied  with  much  pain, 
but  when  exposed  to  view  exhibits  no  sign  of 
inflammation.  There  is  no  vascularity  To  be 
observed,  no  granulations,  frequently  no  pus, 
rior  any  unhealthy  appearance  of  the  synovial 
membrane.  Should  the  ulcer,  however,  have 
extended  itself  quite  through  the  cartilage  to 
the  bone,  the  latter  usually  becomes  carious, 
pus  is  secreted  abundantly,  and  the  synovial 
membrane  sympathizes.  The  surface  of  the 
ulcer  differs  very  much  in  different  cases ;  in 
some  it  appears  smooth,  and  of  the  colour  of 
healthy  cartilage,  as  if  a  portion  were  chiselled 
out.  In  others,  and  more  generally,  it  is  a  little 
yellowish,  dull  looking,  and  slightly  irregular. 
The  edges  are  often  irregular,  never  elevated 
nor  undermined.  The  ulceration  sometimes 
spreads  superficially  over  a  large  extent;  at 
other  times  it  is  small  and  deep,  or  it  may 
destroy  all  the  cartilage  and  expose  the  bone, 
which  will  also  be  found  diseased.  Most 
generally  the  remaining  cartilage,  if  any,  retains 
its  healthy  structure  to  the  very  edge  of  the  ab- 
sorbed portion. 

Another  appearance  is  often  observed;  a  part 
of  the  cartilage  is  reduced  to  a  fibrous  state,  the 
fibres  being  attached  at  one  extremity  to  the 
bone,  while  at  the  other  they  are  free,  and  have 
no  lateral  connexion.  This  condition  of  carti- 
lage is  said,  by  Sir  B.  Brodie,  to  be  frequently, 
but  not  constantly,  the  first  stage  of  ulceration ; 
and  he  conceives  it  may  often  exist  where  no 
ulceration  is  ever  to  follow.  Mr.  Key  looks  on 
it  as  "  a  disease  of  a  peculiar  character."  And 
we  have  frequently  found  it  in  the  dissecting 
room,  where  there  was  not  the  slightest  mark 
externally  or  internally  of  any  other  morbid 
action.  The  write/  has  observed  it  oftener  on  the 
patella  than  elsewhere  ;  and  as  this  is  so  seldom 
the  part  first  involved  in  the  ulcerative  process, 
it  probably  depends  on  an  action  of  a  different 
nature.  The  writer  has  also  seen  it  oftener  in 
joints  long  dead  than  in  the  more  recent,  and  has 
therefore  thought  it  might  possibly  be  caused, 
in  some  cases  at  least,  by  the  action  of  the 
synovial  fluid,  or  by  decomposition. 

Secondary  ulceration  may  commence  in  the 
bone  or  in  the  synovial  membrane,  (a)  When 
the  bone  is  previously  diseased,  that  side  of  the 
cartilage  which  was  turned  to  it  is  first  affected. 
The  adhesion  of  the  two  tissues  is  diminished ; 
we  find  it  more  easy  to  separate  them.  After 
some  time  a  separation  actually  takes  place,  and 
a  vascular  net-work,  sometimes  a  layer  of  granu- 
lations, occupies  the  interval.  The  surround- 
ing cartilage  is  softened.  The  ulcer,  with  cha- 
racters differing  little  from  the  primary  form, 
goes  on  more  or  less  rapidly,  until  an  opening 
is  made  quite  through  into  the  cavity  of  the 
joint.  When  this  opening  is  effected,  the  mat- 
ter, which  in  this  form  of  ulcer  is  always  pre- 


500 


CAVITY. 


sent,  finds  its  way  into  the  synovial  sac,  and  ex- 
cites inflammation  there. 

The  disease  of  the  bone  commonly  giving 
rise  to  this  ulcer  is  the  slow  strumous  affection 
of  the  spongy  extremities,  so  accurately  de- 
scribed by  Sir  B.  Brodie,  the  symptoms  of 
which  are  familiar  to  every  surgeon.  A  more 
acute  inflammation  of  the  osseous  tissue  is  oc- 
casionally to  be  seen,  and  may  be  followed  by  a 
disease  of  the  same  nature,  or  differing  only  in 
the  quickness  of  the  course  it  pursues. 

(6)  Secondary  inflammation  extending  from 
the  synovial  membrane  is  most  apt  to  attack 
the  edges  of  the  cartilages  in  the  first  instance. 
These  are  thinned,  as  if  abraded,  and  over- 
lapped by  the  vascular  or  disorganized  mem- 
brane. The  bone  remains  sound,  as  in  the 
primary  ulceration.  For  further  particulars  on 
the  ulceration  of  cartilage,  see  JOINT. 

Does  fractured  cartilage  ever  unite  by  cartilage? 
It  probably  never  does.  The  costal  cartilages, 
when  broken,  unite  by  lymph,  which  soon  after 
is  converted  in  bone,  but  never  appears  to  form 
true  cartilage.  When  a  fracture  extends  into  a 
joint,  as  we  often  see  in  the  condyles  of  the 
humerus  and  femur,  the  divided  cartilage  is 
united  by  a  cicatrix,  which  is  not  truly  car- 
tilaginous. Neither  does  it  appear  that  car- 
tilage is  ever  regenerated.  Laennec  believed  it 
was :  "  in  examining  a  knee-joint,  he  found  in 
the  centre  of  the  articulating  surfaces,  in  place 
of  the  natural  cartilage,  a  thin  cartilaginous 
lamina,  semitransparent,  adherent  to  the  bone; 
the  old  cartilage  formed  around  it  a  projecting 
border,  as  if  fimbriated."* 

This  observation  certainly  was  not  enough  to 
establish  its  power  of  regeneration.  We  often 
find  in  cases  of  gout  and  rheumatism,  and 
especially  in  the  disease  designated  morbus  coxa 
senilis,  that  the  cartilage  is  removed,  and  in  its 
place  a  compact  shining  layer  of  osseous  sub- 
stance like  ivory  deposited.  This  is  not  owing  to 
an  ossification  of  the  cartilage,  for  the  cartilage  is 
often  found  completely  absorbed,  and  the  rough 
bone  exposed,  which,  if  seen  at  a  later  period, 
would  doubtless  be  covered  with  this  deposit  to 
prevent  the  disintegration  of  its  cancellated 
structure. 

BIBLIOGRAPHY — Hunter  on  the  structure  and 
diseases  of  articulating  cartilages,  Philos.  Trans. 
1743.  Haase,  De  fabrica  cartilaginum,  4to.  Lips. 
1767.  Authenrieth,  De  gravioribus  quibusdara 
cartilaginum  mutationibus,  8vo.  Tubing.  1798. 
Mayo,  Acute  form  of  ulceration  of  the  cartilages 
of  joints,  Medico-Chirurg.  Trans,  vol.  xi.  Cru- 
veilhier,  Obs.  sur  les  cartilages  diarthrodiaux,  et 
les  maladies  des  articulations,  Archives  Gen.  de 
Med.  t.  iv.  1824;  Ej.  Usure  des  cartilages  articu- 
laires,  Nouv.  Biblioth.  Med.  t.  i.  Observations 
on  accidental  or  loose  cartilages  may  be  found,  by 
Cruikshanh,  in  Med.  and  Philos.  Co'mm.  of  Edinb. 
vol.  iv.  ;  by  Coley,  in  Med.-Chir.  Trans  vol.  v.  : 
by  Horne,  in  Trans,  of  a  Society  for  Improv.  Med. 
and  Chirurg.  Knowledge,  vol.  i. ;  by  Desault,  in 
his  Journ.  de  Chirurg.  t.  ii.  ;  by  Abernethy,  in  his 
Surg.  Observations ;  by  Laennec,  in  the  art.  Car- 
tilages Accidentels  of  the  Diet,  des  Sc.  Med.  •  by 
Cruveilhier,  in  Nouv,  Bib.  Med.  t.  i.  1827  ;  '&c. 
And  remarks  on  special  forms  of  disease  affecting 
the  cartilages  occur  in  the  general  treatises  on  dis- 

*  Op.  cit.  p.  240. 


eases  of  .the  joints,  as  those  of  Cooper,  Brodie, 
Schreger,  Wilson,  and  Scott.—  Vide  Bibliography  of 
ARTICULATION. 

(Charles  Benson.) 

CAVITY,  in  anatomy,  (cavitas;  Fr.cavite; 
Germ.  Hohle;  Ital.  cavita.} — This  term  is  used, 
in  anatomy,  to  signify  any  excavation  or  even 
depression  of  more  than  ordinary  depth,  which 
may  exist  in  or  between  solid  parts.  Hence 
we  find  cavities  existing  in  bones,  or  formed 
by  the  junction  of  one  or  more  bones,  which,  as 
they  are  severally  destined  for  articulation  with 
other  bones,  or  for  the  reception  or  transmis- 
sion of  certain  tendons,  vessels,  &c.  are  de- 
signated articular  or  non-articular.  (See  BONE.) 

But  we  have  likewise  large  excavations  whose 
walls  are  of  a  more  complicated  arrangement, 
and  which  are  destined  to  receive  and  protect 
those  organs  which  are  concerned  in  the  func- 
tions of  innervation,  respiration,  and  digestion, 
and  throughout  a  large  proportion  of  the  classes 
composing  the  animal  kingdom  are  three  in 
number,  namely,  the  CEPHALIC  or  CRANIAL 
cavity,  containing  the  brain — the  THORACIC 
cavity,  containing  the  organs  of  respiration — 
and  the  ABDOMINAL  cavity,  containing  the 
organs  of  digestion  and  of  the  secretion  of 
urine.  To  this  last  is  appended,  as  a  continua- 
tion, the  PELVIC  cavity,  which  is  chiefly  de- 
voted to  the  organs  of  generation,  as  well  as  to 
some  of  those  connected  with  the  urinary  ex- 
cretion. We  refer  for  particulars  connected 
with  the  other  cavities  to  the  articles  CRANIUM, 
THORAX,  and  PELVIS,  and  proceed  to  consider 
succinctly  the  anatomy  of  the  ABDOMINAL 
CAVITY  in  its  Normal  as  well  as  Abnormal 
conditions.* 

ABDOMINAL  CAVITY,  (in  human  anatomy.) 

The  annexed  woodcut  exhibits  a  vertical 
section  of  the  body  intended  to  show  the  tho- 
racic and  abdominal  cavities,  from  which  the 
viscera  have  been  removed.  A  simple  reference 
to  it  and  to  Jig.  204  will  sufficiently  explain  the 
form  and  boundaries  of  the  latter  cavity,  which 
have  been  already  fully  described  in  the  article 
ABDOMEN.  Our  object  in  the  present  article 
is  to  examine  the  abdominal  cavity  as  it  is 
brought  under  the  eye  of  the  anatomist,  when 
its  contents  have  been  exposed  by  removing  or 
cutting  through  the  abdominal  parietes. 


*  Some  anatomists  object  to  the  use  of  the  term 
cavity,  because,  say  they,  every  hollow  in  the 
animal  body  is  fuH.  Such  an  objection,  on  the 
principle  of  nature's  abhorrence  of  a  vacuum, 
would  go  to  discard  the  use  of  the  term,  even  from 
ordinary  discourse.  Considering  the  word  in  re- 
ference to  its  etymology,  it  is  synonymous  with 
excavation,  which  in  no  way  implies  emptiness, 
and  it  is  in  this  sense  that  we  must  employ  it 
in  anatomical  description.  I  apprehend  that  con- 
fusion has  arisen  from  employing  the  same  word  to 
denote  the  excavation  bounded  by  bone  or  by  bone 
and  muscle,  in  which  the  viscus  or  viscera  are 
lodged,  and  to  indicate  the  bag  or  sac  of  the  serous 
membrane  by  which  each  of  the  three  great  cavi- 
ties is  lined.  In  this  latter  sense,  the  term  cavity 
is  certainly  not  appropriate,  at  least  it  may  be 
most  advantageously  laid  aside  ;  and  we  can  use, 
without  the  same  risk  of  confusion,  the  expression 
bag  or  sac  of  the  peritoneum,  pleura,  &c. 


CAVITY. 


501 


Fig.  203. 


—  d 


proper  epigastric  region,  covering  and  con- 
cealing the  lesser  curvature  of  the  stomach 
with  the  gastro-hepatic  omentum  and  the  ante- 
rior, or  more  correctly,  the  antero-superior 
surface  of  the  stomach  to  a  variable  extent. 
In  this  region  we  likewise  see,  corresponding 
pretty  nearly  to  the  cartilage  of  the  ninth  rib, 
the  fundus  of  the  gall-bladder  in  some  in- 
stances completely  covered  by  the  liver,  in 
others  projecting  beyond  it  or  only  covered  by 
a  duplicature  of  serous  membrane  which  fills 
up  a  natural  notch  in  the  liver.  In  the  epigas- 

Fig.  204. 


It  rarely  happens  that  we  meet  with  an  in- 
stance in  which  the  abdominal  viscera  have 
not  been  more  or  less  disturbed  after  death 
from  their  natural  relations  to  one  another. 
During  life  the  contractile  walls  of  the  ab- 
domen, ever  active,  maintain  such  a  uniform 
degree  of  pressure  on  the  contained  organs, 
that  displacements  or  alterations  of  positions 
are  very  rare  occurrences  excepting  through 
some  preternatural  opening  in  the  abdominal 
parietes.  It  is  advisable  to  study  the  positions 
of  the  contents  of  the  abdomen  in  a  body  re- 
cently dead,  and  which  has  not  experienced 
any  degree  of  disturbance. 

When  the  anterior  wall  of  the  abdomen  has 
been  removed  or  freely  laid  open  by  a  crucial 
incision,  the  contents  of  the  cavity  are  brought 
into  view  in  the  following  order  :  — 

In  the  right  hypochondriac  region  the  liver 
projects  to  a  slight  extent  below  the  inferior 
border  of  the  chest.  This,  however,  is  not  to 
be  regarded  as  the  position  of  the  liver  during 
life ;  the  descent  of  that  organ  from  behind  the 
shelter  of  the  ribs  is  attributable  to  its  gravita- 
tion in  consequence  of  the  removal  of  the 
support  which  it  obtained  from  the  pressure  of 
the  anterior  abdominal  wall.  The  liver  will 
thus  be  found  to  extend  more  or  less  into  the 


trium  more  or  less  of  the  stomach  is  seen,  its 
greater  curvature  projecting  forwards,  having 
pendent  from  it  the  middle  portion  of  the  great 
omentum;  and  the  left  hypochondrium  often 
(especially  when  the  stomach  is  full)  seems  to 
be  wholly  occupied  by  the  splenic  extremity  of 
the  stomach,  immediately  below  which  there 
is  a  portion  of  the  transverse  colon,  just  where 
it  is  forming  an  angle  with  the  descending 
colon.  Sometimes  the  anterior  margin  of  the 
spleen  projects  before  it,  and  sometimes  a  still 
greater  portion  of  the  spleen  is  visible,  if  that 
organ  be  in  a  state  of  turgescence.  Along  the 


502 


CAVITY. 


inferior  boundary  of  the  epigastric  region,  and 
projecting  partly  into  that  region  and  partly 
into  the  umbilical  below,  the  transverse  arch 
of  the  colon  runs  with  a  slight  curve  concave 
backwards  and  downwards.  The  position  of 
this  important  portion  of  the  great  intestine  is 
always  lower  in  the  abdomen  of  a  subject  thus 
opened  than  it  can  possibly  be  during  life.  In 
fact,  when  the  abdominal  wall  is  unimpaired 
and  the  usual  compression  is  maintained,  the 
stomach  and  colon  must  be  in  very  close  appo- 
sition with  each  other,  so  that  it  must  be  diffi- 
cult, if  not  impossible,  to  make  pressure  from 
without  on  the  one  without  affecting  the  other 
nearly  to  the  same  degree.  The  arch  of  the 
colon  is  loosely  covered  on  its  anterior  surface 
by  two  laminae  of  peritoneum,  which  descend 
from  the  greater  curvature  of  the  stomach  and 
entering  into  the  umbilical  region  are  reflected 
upwards  after  a  descent  as  far  as  the  lowest 
part  of  that  region,  forming  a  curtain  which 
covers  the  convolutions  of  the  small  intestine 
beneath  the  transverse  arch  of  the  colon.  This 
curtain  is  the  great  Omentum  or  Epiploon, 
(Omentum  majus,)  which,  in  the  natural  con- 
dition of  the  parts  during  life,  there  is  every 
reason  to  believe  is  closely  applied  to  the  an- 
terior surface  of  the  small  intestine;  much 
variety,  however,  may  be  observed  as  to  the 
extent  of  its  relation  to  this  portion  of  the 
intestinal  canal,  and  it  is  difficult  to  account  for 
this  variety.  Thus  we  sometimes  find  the  in- 
testine uniformly  covered  by  this  membrane 
more  or  less  loaded  with  fat,  descending  as 
low  as  the  upper  outlet  of  the  pelvis ;  this 
may  be  regarded  as  the  normal  state  in  the 
adult.  But  at  other  times  we  find  the  omentum 
so  crumpled  up  or  contracted,  that  the  small 
intestine  is  completely  exposed,  and  it  is  only 
by  pulling  down  the  omentum  from  the  arch 
of  the  colon  towards  which  it  is  folded  up  or 
crumpled,  that  we  can  form  an  estimate  of  its 
extent.  Again,  in  other  cases  we  observe  that 
it  is  only  long  enough  to  descend  halfway  or  a 
little  lower  over  the  surface  of  the  small  intes- 
tine. It  is  said  to  have  less  extent  in  females 
who  have  borne  many  children  than  in  any 
others ;  I  cannot  confirm  this  statement,  inas- 
much as  I  have  not  unfrequently  seen  it  of  its 
full  dimensions  in  such  subjects.  In  the  na- 
tural state  of  the  parts,  then,  the  whole  of  the 
central  portion  of  the  umbilical  region  is  oc- 
cupied by  the  omentum,  forming  a  moveable 
curtain  over  the  anterior  surface  of  the  con- 
volutions of  the  jejunum  and  ilium. 

The  iliac  region  of  the  right  side  is  occupied 
by  the  ccecum  or  caput  coli,  and  in  the  lumbar 
region  of  the  same  side  the  ascending  colon  is 
visible,  sometimes  when  distended  projecting 
considerably,  at  other  times  so  contracted  as  to 
appear  sunk  towards  the  posterior  wall  of  this 
region,  and  to  allow  of  being  overlapped  and 
concealed  from  view  by  some  of  the  convo- 
lutions of  the  small  intestine.  In  the  corres- 
ponding regions  of  the  left  side  the  remaining 
portions  of  the  colon  are  seen,  and  they  too 
are  very  frequently,  if  not  generally,  closely 
applied  to  the  posterior  wall:  in  the  lumbar 
region  the  descending  colon  is  much  more 


frequently  in  a  contracted  than  in  a  distended 
state,  and  in  the  iliac  region,  not  occupying  it 
to  the  same  extent  as  its  fellow  is  occupied  by 
the  crecum,  we  find  the  sigmoid  flexure  of  the 
colon  winding  its  curved  course  over  the  psoas 
muscle,  and  sinking  into  the  pelvis  to  assume 
the  name  of  rectum.  The  lower  convolutions 
of  the  small  intestine  invariably  fill  up  the 
superior  outlet  of  the  pelvis,  and  are  found  to 
a  greater  or  less  extent  in  that  cavity,  in  pro- 
portion as  the  bladder  and  rectum  are  empty 
or  the  reverse. 

Such  being  the  position  of  the  parts  as  they 
appear  when  the  anatomist  lays  open  the  ab- 
domen in  a  recent  subject,  we  proceed  now  to 
examine  what  parts  are  found  in  each  com- 
partment of  this  cavity,  and  the  relation  which 
they  bear  to  each  other.  We  may  observe, 
in  passing,  that  there  cannot  be  much  difference 
in  the  position  of  the  abdominal  organs  during 
life,  even  in  the  varied  attitudes  of  the  body, 
from  that  which  we  find  them  to  possess  in  a 
body  recently  dead.  Making  allowance  for 
the  pressure  which  is  maintained  upon  them 
by  the  abdominal  parietes,  it  is  obvious  that 
the  position  of  each  organ  during  life  will  be 
higher  in  the  abdomen  than  that  which  it  occu- 
pies in  the  dead  body ;  all  the  organs  are  more 
firmly  applied  to  one  another  and  to  the  pos- 
terior wall  of  the  abdomen. 

It  is  not,  however,  unimportant  to  bear  in 
mind  that  such  is  the  nature  of  the  contents 
of  the  hollow  abdominal  viscera,  and  such  the 
rapidity  with  which  they  become  accumulated, 
that  changes  of  relation  may  be  rapidly 
effected.  Thus  the  stomach,  or  any  part  of  the 
intestinal  canal,  may  by  a  rapid  accumulation 
of  air  or  any  other  matter  within  it,  occupy 
a  much  more  extensive  portion  of  the  abdo- 
men than  it  usually  does  in  the  natural  state. 
This  is  allowed  by  the  extraordinary  com- 
pressibility of  the  other  viscera,  a  com- 
pressibility which  is  every  day  exemplified  in 
pregnancy,  aud  in  cases  of  ovarian  dropsy, 
of  ascites,  &c. 

1 .  The  epigastric  region. — The  right  extre- 
mity of  this  region  or  the  right  hypochondrium 
is  occupied  almost  entirely  by  the  liver,  which 
is  connected  with  the  diaphragm  and  anterior 
wall  of  the  abdomen  by  the  folds  of  perito- 
neum which  form  what  are  called  the  ligaments 
of  the  liver.  When  the  left  lobe  of  the  liver 
is  raised  up,  we  see  the  lesser  or  gastro-hepatic 
omentum  extended  between  the  lesser  curvature 
of  the  stomach  and  the  transverse  fissure  of 
the  liver.  A  defined  margin  terminates  the 
gastro-hepatic  omentum  on  the  right  side,  just 
adjoining  the  neck  of  the  gall-bladder:  if  the 
finger  be  pushed  underneath  this  margin  from 
right  to  left,  it  passes  through  an  opening  which 
leads  into  the  cavity  of  the  omentum,  and  if 
continued  downwards  behind  the  stomach  will 
separate  the  laminae  of  the  great  omentum. 
This  opening  is  commonly  known  under  the 
name  of  the  Foramen  of  Winslow :  the  lesser 
omentum  bounds  it  in  front,  behind  it  lie  the 
supra-renal  capsule,  the  vena cava  ascendens,and 
the  psoas  muscle,  covered  by  a  lamina  of  perito- 
neum which  ascends  towards  the  diaphragm, 


CAVITY. 


503 


after  having  partly  covered  the  duodenum.* 
The  lesser  splanchnic  nerve  will  also  be  found 
in  this  situation  lying  on  the  quadratus  lum- 
borum  muscle  and  on  the  psoas,  and  descend- 
ing to  throw  itself  into  the  renal  plexus.     On 
a  plane  posterior  to  the  lesser  omentum  the 
inferior  surface  of  the  liver  is  in  contact  with 
the  kidney,  and  with  the  angle  of  junction  of 
the  ascending  and  transverse  portions  of  the 
colon,  as  is  proved  by  the  frequent  adhesion  of 
this  intestine  to  the  liver.     The   situation   of 
the  gall-bladder  in  this  region  demands  atten- 
tion ; — its  fundus  corresponds  to  the  cartilage 
of  the  ninth  rib,  beneath  which  it  sometimes 
projects  to  an  extent  proportionate  to  the  de- 
gree to  which  it  is  distended  ;  hence  it  is  evi- 
dent that  an  unusually  distended   gall-bladder 
is  not  unlikely  to  form  a  tumour  below  the 
margin  of  the  ribs  presenting  all  the  characters 
of  an  hepatic  abscess.f     The  gall-bladder  is,  in 
this  region,  in  close  connexion  either  by  its  neck 
or  body,  with  the  duodenum  or  tranverse  colon, 
a  fact  which  explains  the  evacuation  of  gall- 
stones into  either  of  those  intestines.     The  left 
lobe  of  the  liver  projects  more  or  less  into  the 
central  portion  of  the  epigastric  region,  or  that 
which  is  called  the  proper  epigastrium.     Here 
it  is  in  contact  by  its  concave  surface  with  the 
anterior  superior  surface  of  the  pyloric  half  or 
third  of  the  stomach.    This  latter  viscus  when 
contracted  lies  very  far  back  in  the  epigastric 
excavation,  and  extends  towards  the  left  side, 
so  as  to  occupy  the  left  hypochondrium  to  a 
great  extent.     Its  pyloric  third  or  half  is  in 
contact  with  the  liver,  the  remaining  or  cardiac 
portion   is   in   contact  with    the   diaphragm ; 
hence  it  is  always  the  displaced  organ  in  dia- 
phragmatic hernia.      This   close  connexion  of 
the  stomach  and  diaphragm  likewise  explains 
the  peculiar    sonorousness   which    percussion 
frequently  elicits  over  the  left  hypochondrium 
and  even  for  some  distance   up  the  anterior 
surface  of  the  thorax,  so  that  when  the  sto- 
mach   is  large  and  flatulent,  it  is  often  very 
difficult  to  ascertain  whether  the  sound  pro- 
duced and  heard  in  this  region  results  from  an 
effusion  of  air  and  liquid   into  the  thorax,  or 
from  such  a  stomach  rilled  partly  with  liquid 
and    partly  with  air.     When   the   stomach  is 
full,  the  aspect  of  its  superior  surface  is  more 
directly  upwards  and  less  forwards  than  in  the 
empty  state  ;  but  a  considerable  portion  of  the 
anterior  part  of  this  surface,  as  well  as  of  the 
greater  curvature,  is  in  contact  with  the  abdo- 
minal parietes.     The  great  curvature  of  the 
stomach  for  three-fifths  of  its  extent  towards 
the  pylorus  is  closely  connected  with  the  upper 


*  Blandin  records  a  remarkable  case  of  internal 
stiangulation  which  took  place  by  the  introduction 
of  a  considerable  portion  of  the  small  intestine 
through  the  foramen  of  Winslow  into  the  cavity  of 
the  omentum,  from  which  it  escaped  through  a 
lacerated  opening  in  the  transverse  mesocolon 
which  firmly  constricted  a  knuckle  of  the  intestine 
and  occasioned  mortification  of  it. —  Anat,  Topoq. 
p.  442. 

t  See  cases  recorded  by  Andral,  Clin.  Med.  t.  iv. 
and  Graves,  Dublin  Hosp.  Rep.  vol.  iv. 


surface  of  the  transverse  arch  of  the  colon, 
and  with  the  two  anterior  laminae  of  the  great 
omentum  which  come  in  contact  along  the  line 
of  that  curvature,  enclosing  between  them  the 
anastomosis    of    the    gastro-epiploic    arteries. 
Hence  we  sometimes  find  that,  in  cases  of  per- 
foration of  the  stomach,  the  opening  is  filled  up 
by  the  adhesion  of  the  wall  of  the  colon  to  the 
serous  coat  of  the  former  viscus,  and  the  effusion 
of  its  contents  is  thereby  prevented ;  and  it  has 
been   said    that   fluids   may  pass  through  an 
ulcer  of  the  great  curvature  and  be  effused 
between  the  laminae  of  the  omentum,  so  as  to 
point  externally  as  an  abscess.*     The  extent  of 
the  relation  of  the  stomach  to  the  liver  varies ; 
in  some  instances  it  extends  as  far  outwards  as 
the  gall-bladder ;  and  Cruveilhier  mentions  a 
case  in  which  gall-stones  were  discharged  into 
the  stomach  in  consequence  of  an  adhesion 
formed  by  its'  anterior  surface  with  the  gall- 
bladder.   The   stomach  rests  by  its  posterior 
and  inferior  surface  on  the  superior  lamina  of 
the  transverse  mesocolon,  which  forms  a  natural 
floor  to  the  epigastric  region,  and  separating  it 
from  the  umbilical  region.       Posteriorly  the 
same  lamina  of  the  transverse  mesocolon  sepa- 
rates it  from  the  inferior  transverse  portion  of 
the  duodenum  and  from  the  head  of  the  pan- 
creas, which  again  are  separated  from  the  spine 
by   the   aorta  and   crura   of   the   diaphragm. 
The  lobulus  Spigelii  of  the  liver  is  seen  behind, 
arid  to  the  left  of  the  lesser  curvature  of  the 
stomach,  and  when  the  latter  is  drawn  down- 
wards and  the  liver  forwards,  this  lobe  projects, 
pushing  the  gastro-hepatic  omentum  before  it ; 
the   lesser  curvature  has  likewise  among  its 
connections    posteriorly  the   coeliac  axis   and 
solar  plexus,  and  like  the  great  curvature  has 
an  arterial  anastomosis  running  along  it  formed 
by  the  superior  pyloric   and   gastric   arteries. 
The  spleen  is  very  intimately  connected  by  the 
gastro-splenic  omentum  to  the  left  extremity  or 
great  cul-de-sac  of  the  stomach,  and  seems, 
as  it  were,  moulded  upon  it,  following  it  in  its 
movements,  and  each  accompanying  the  other 
in  its  displacements :   behind   this  portion  of 
the  stomach  are  the  tail  of  the  pancreas,  the 
left  kidney,    and   supra-renal   capsule.      The 
point  of  entrance  of  the  oesophagus  into  the 
cardiac  extremity  of  the  stomach  is  overlapped 
by  the  left  lobe  of  the  liver  and  its  left  lateral 
ligament,   and  it  rests  upon   the  decussating 
muscular  bundles  of  the  diaphragm .f 

In  the  epigastric  region  we  likewise  find  the 
first  portion  of  the  duodenum  passing  from 
left  to  right  slightly  upwards  and  backwards, 
terminating  at  the  neck  of  the  gall-bladder, 
with  which  it  often  contracts  preternatural 
adhesions.  Behind  this  superior  portion  of 
the  duodenum,  a  little  to  the  left  of  its  ter- 
mination, the  ductus  communis  choledochus 


*  Ledran,  quoted  by  Velpeau,  Anat.  Chir.  t.  ii. 
p.  165. 

t  From  the  relations  of  the  stomach  to  the  abdo- 
minal parietes  we  are  not  surprised  to  read  of  fistu- 
Ions  communications  being  formed  between  that 
viscus  and  various  regions  of  the  abdominal  surface. 


504 


CAVITY. 


descends  to  enter  the  middle  portion  of  this 
intestine,  the  upper  part  of  which  is  likewise 
found  in  this  region.  Here,  too,  we  have  the 
upper  half  of  the  head  of  the  pancreas,  the 
right  gastro-epiploic  and  the  gastro-duodenalis 
arteries. 

In  proceeding  to  remove  the  parts  which 
lie  most  superficially  in  the  epigastric  region, 
we  notice  on  the  right  side  the  vessels  and 
nerves  enclosed  between  the  laminae  of  the 
lesser  omentum,  viz.  the  hepatic  artery  and 
its  terminal  branches,  the  vena  portae,  and 
the  hepatic  and  cystic  ducts,  with  the  com- 
mencement of  the  ductus  communis  chole- 
dochus,  and  entwining  its  filaments  chiefly 
around  the  hepatic  arteries  is  the  hepatic 
plexus  of  nerves ;  several  lymphatic  vessels 
of  considerable  size  are  also  found  here,  and 
some  lymphatic  ganglions,  the  enlargement  of 
which  latter,  whether  acute  or  chronic,  may  retard 
the  passage  of  the  bile  and  give  rise  to  jaundice. 
All  these  parts  are  invested  and  connected  to 
each  other  by  the  dense  cellular  membrane 
called  the  capsule  of  Glisson.  Behind  the 
liver,  and  closely  lodged  in  a  groove,  and 
sometimes  a  canal  in  its  posterior  thick  margin, 
is  the  vena  cava  ascendens,  which  is  still  more 
intimately  connected  with  the  liver  through 
the  branches  of  the  vena  cava  hepatica,  which 
open  into  that  portion  of  the  ascending  vein 
which  is  lodged  in  the  groove.  To  the  right 
of  the  vein  are  the  supra-renal  capsule  and 
the  upper  part  of  the  kidney,  and  to  its  left, 
and  closely  connected  with  the  supra-renal 
capsule,  is  the  semilunar  ganglion.  Here, 
likewise,  are  the  renal  or  emulgent  vessels 
and  the  renal  plexus  of  nerves. 

In  the  centre  of  the  epigastric  region,  on 
removing  the  stomach,  we  open  into  the  lesser 
cavity  of  the  peritoneum,  of  which  the  stomach 
forms,  in  part,  the  anterior  and  superior  boun- 
dary. This  cavity  is  bounded  inferiorly  and 
posteriorly  by  the  descending  layer  of  the  trans- 
verse meso-colon,  which  covers  the  upper  part 
of  the  pancreas;  above  this  latter  gland  is  the 
cceliac  axis,  surrounded  by  the  solar  plexus  of 
nerves,  giving  off  its  terminal  branches,  of  which 
the  hepatic  passes  towards  the  right  side,  and 
forwards  to  the  transverse  fissure  of  the  liver, 
while  the  splenic  directs  itself  tortuously  towards 
the  left  side,  along  the  upper  margin  of  the 
pancreas.  The  pancreas  itself  is  to  be  counted 
among  the  parts  contained  in  this  region ;  here 
it  is  covered  by  the  superior  layer  of  the  trans- 
verse mesocolon,  which  alone  separates  it 
from  the  posterior  surface  of  the  stomach; 
hence  this  gland  has  sometimes,  by  contracting 
an  adhesion  with  the  stomach,  served  to  fill 
up  a  perforation  by  an  ulcer.  Behind  the  pan- 
creas are  the  vena  portae  and  the  conflux  of 
the  splenic  and  superior  mesenteric  veins,  the 
superior  mesenteric  artery,  and  the  nervous 
plexus  of  the  same  name ;  by  all  of  which 
the  gland  is  separated  from  the  aorta,  which, 
again,  with  the  pillars  of  the  diaphragm  and 
some  lymphatic  glands,  separates  the  pancreas 
from  the  spine.  To  the  right  of  the  aorta,  and 
intervening  between  it  and  the  right  crus,  are 


the  thoracic  duct  and  the  vena  azygos,  and 
external  to  each  crus  of  the  diaphragm  the 
great  splanchnic  nerve  is  seen  to  connect  itself 
with  the  semilunar  ganglion. 

On  the  left  side  the  gastro-splenic  omentum 
contains  the  vasa  brevia  and  splenic  arteries, 
the  splenic  plexus  of  nerves,  and  the  com- 
mencement of  the  left  gastro-epiploic  artery ; 
the  great  cul-de-sac  of  the  stomach,  and  the 
spleen  cover  here  the  left  supra-renal  capsule, 
the  semilunar  ganglion  and  great  splanchnic 
nerve,  the  upper  part  of  the  left  kidney,  and 
the  renal  vessels  and  nerves. 

From  the  vast  number  and  importance  of 
the  parts  contained  in  the  epigastric  region,  it 
cannot  be  a  matter  of  surprise  that  it  is  fre- 
quently the  seat  of  disease,  and  that  the  most 
serious  consequences  will  often  ensue  upon 
strong  pressure  or  violence  inflicted  upon  it. 
It  is  universally  known  that  syncope  may  be 
induced  or  even  sudden  death  occasioned  by 
a  blow  upon  the  epigastrium,  even  in  a  healthy 
individual;  and  it  seems  to  be  the  favourite 
opinion  that  such  results  arise  from  the  influence 
exerted  upon  the  immense  nervous  plexus 
which  is  found  here.  Sometimes,  however, 
one  or  more  of  the  viscera  have  experienced 
injury,  and  cases  of  rupture  of  the  spleen, 
liver,  gall-bladder,  or  duodenum  from  violence 
inflicted  on  this  region  are  not  uncommon.* 
Every  practitioner  is  familiar  with  the  existence 
of  epigastric  pulsations,  which,  as  they  arise 
from  a  variety  of  causes,  form  a  subject  of 
great  interest.  Dr.  Copland  thus  enumerates 
these  causes,  and,  indeed,  most  of  them  may 
be  deduced  a  priori  from  a  knowledge  of  the 
anatomy  of  the  region :  «,  nervous  suscepti- 
bility; b,  inflammation  of  the  aorta;  c,  aneu- 
rism of  the  aorta;  d,  adhesion  of  the  pericar- 
dium to  the  heart ;  e,  tumours  at  the  root  of 
the  mesentery ;  f,  tumours  of  the  stomach  or 
scirrhus  of  the  pylorus ;  g,  enlargement  of  the 
pancreas ;  A,  hypertrophy  of  the  heart,  parti- 
cularly of  its  right  side ;  i,  enlargement  of  the 
inferior  vena  cava ;  k,  hepatisation  of  the  lower 
portion  of  the  lungs ;  /,  enlargement  of,  or 
abscess  in,  the  liver,  f 

Umbilical  region. — This  region  is  distinctly 
and  naturally  separated  from  the  epigastrium 
by  the  transverse  arch  of  the  colon  and  the 
transverse  mesocolon.  It  is  almost  entirely 
occupied  in  the  centre  by  the  small  intestines, 
and  on  each  side  by  the  colon,  either  ascending 
or  descending.  Deep  seated  and  at  the  upper 
part  of  the  region,  we  notice  the  inferior  portion 
of  the  duodenum,  which  is  covered  by  the  infe- 
rior lamina  of  the  transverse  mesocolon,  and  ter- 
minates on  the  left  side  of  the  spine,  just  where 
the  mesentery  commences.  The  superior  me- 
senteric artery  crosses  above  and  in  front  of 
the  duodenum,  a  few  lines  to  the  right  of  its 
termination,  and  when  the  body  is  laid  on  the 
back  the  intestine  seems  to  suffer  a  constriction 
from  the  artery.  Such  a  constriction  can  hardly 

*  See  an  interesting  paper  by  Dr.  Hart,  in  the 
Dub.  Hosp.  Reports,  vol.  v. 

t  Diet.  Pract.  Med.  art.  Epigastrium, 


CAVITY. 


505 


exist  during  life,  when  the  viscera  of  the  abdo- 
men are  under  the  influence  of  the  action  of 
its  walls,  for  then  the  direction  of  the  superior 
mesenteric  artery  is  so  little  downwards  and  so 
much  forwards  that  it  cannot  be  said  to  exert 
any  pressure  upon  the  intestine;  yet  it  is 
remarkable  that  in  many  cases  of  ruptured 
intestine,  the  seat  of  the  rupture  has  been  a 
very  short  way  below  the  continuation  of  the 
duodenum  into  the  jejunum.  The  inferior 
portion  of  the  duodenum  rests  upon  the  vena 
cava  and  the  aorta,  and  is  in  contact  with 
these  vessels  by  its  posterior  wall.  The 
inferior  margin  of  this  intestine  descends  to 
very  near  the  bifurcation  of  the  aorta,  leaving 
no  more  than  from  one-half  to  three-fourths  of 
an  inch  interval.  We  notice,  moreover,  in 
this  region  the  obliquity  of  the  mesentery, 
the  arterial  and  venous,  nervous  and  lacteal 
ramifications  existing  between  its  laminae  and 
the  mesenteric  glands  or  ganglions  connected 
with  the  lacteals,  which  ganglions  are  often 
very  few  and  much  atrophied  in  old  subjects. 
The  convolutions  of  the  small  intestine  are 
covered  in  front  by  the  omentum,  and  are  very 
closely  in  apposition  with  each  other  :  hence 
they  become  '  matted  together 'by  the  lymph 
effused  in  peritonitis,  and  hence,  too,  in  per- 
forations, effusion  of  the  intestinal  contents 
by  no  means  necessarily  takes  place.  The 
looseness  of  the  intestinal  convolutions  and  of 
the  mesentery  by  which  those  convolutions  are 
tied  to  the  spine,  admits  not  only  of  their 
being  liable  to  frequent  introsusception,  but 
also  of  being  strangulated  by  the  twisting  of  a 
knuckle  of  intestine.  For  the  same  reason  it 
is  that  we  find  this  intestine  forming  most 
of  the  hernias  which  protrude  from  the  various 
regions  of  the  abdomen.  The  small  intestine 
occupies  the  whole  central  umbilical  region, 
extending  likewise  on  either  side  into  the  lum- 
bar regions  and  downwards  into  the  pelvis. 
Thus  it  forms  a  considerable  mass  interposed 
between  the  anterior  and  posterior  abdominal 
walls,  and  it  is  easy  to  conceive  how,  during 
an  irregularly  distended  state  of  the  intestine, 
violence  applied  to  the  abdomen  in  front  can 
cause  a  rupture  of  a  part  of  it  without  occa- 
sioning any  solution  of  continuity  in  the  wall 
of  the  abdomen. 

The  laminae  of  the  mesentery  pass  back- 
wards and  outwards  along  the  sides  of  the 
spine,  and  entering  the  lumbar  regions  become 
continuous  with  the  right  and  left  mesocolons. 
By  their  divergence  in  front  of  the  spine  they 
form  a  triangular  enclosure,  the  basis  of  which 
is  formed  by  the  bodies  of  the  vertebrae.  In 
this  space  we  find  the  aorta,  and  lower  down 
the  primitive  iliac  arteries,  the  commencement 
of  the  thoracic  duct,  the  receptaculum  chyli, 
and  several  tributary  lymphatics  and  lacteals 
with  their  ganglions,  the  vena  cava  ascendens, 
and  the  left  renal  vein,  the  lumbar  arteries  and 
veins,  and  many  nervous  ramifications  from 
the  sympathetic,  and  more  on  the  sides  the 
lumbar  ganglia  of  the  same  nerve;  here  also 
we  notice  the  fibrous  insertions  of  the  crura 
of  the  diaphragm,  and  the  anterior  common 
ligament  of  the  vertebrae.  Each  lamina  of  the 

VOL.  I. 


mesentery,  as  it  passes  outwards,  crosses  over 
the  ureter  lying  on  the  p.soas  muscle,  and  the 
spermatic  artery  with  the  accompanying  veins, 
and  some  of  the  musculo-cutaneous  branches 
of  the  lumbar  plexus,  and  having  entered 
the  lumbar  region,  covers  the  right  and  left 
colons,  forming,  at  its  reflections  on  and  off 
the  intestine,  the  mesocolons.  Each  of  these 
portions  of  the  colon  lies  very  nearly  con- 
nected to  the  posterior  wall  of  each  lumbar 
region,  having  only  the  lower  portion  of  the 
kidney,  with  its  surrounding  adeps,  interposed 
above.  In  some  instances  a  mesocolon  does 
not  exist,  and  the  colon  is  bound  down  to  the 
posterior  wall  of  the  lumbar  region,  so  that 
the  posterior  surface  of  the  intestine  uncovered 
by  peritoneum  is  in  direct  contact  with  the 
quadratus  lumborum  muscle  or  the  kidney, 
having  only  cellular  membrane  or  fat  inter- 
vening, and  this  occurs  much  more  frequently 
at  the  left  than  at  the  right  side :  hence  the 
not  uncommon  occurrence  of  lumbar  abscess, 
or  renal  abscess,  or  calculi  being  discharged 
into  the  colon,  and  so  finding  their  way  out  by 
stool.  The  proximity  too  of  the  portions  of 
the  colon  to  the  ureters  serves,  as  Velpeau  has 
remarked,  to  explain  how  pins,  or  beans,  or 
pieces  of  lead  find  their  way  into  the  bladder 
and  become  the  nuclei  of  calculi  there, 
or  being  impeded  in  their  progress  through 
the  ureter,  the  calculous  matter  concretes 
around  them  in  that  canal.  In  confirmation 
of  this  explanation,  he  relates  a  case  which 
occurred  at  La  Pine".  A  pin,  the  head  of 
which  was  still  found  in  the  colon,  in  which 
it  had  excited  considerable  ulceration,  had 
passed  also  into  the  ureter,  so  that  a  calculus, 
of  which  the  pin  formed  the  axis,  projected 
partly  within  and  existed  partly  without  the 
canal  of  the  ureter.*  Whether  the  mesocolons 
exist  or  not,  the  right  and  left  colons  are  in 
general  so  fixed  in  situ,  that  they  rarely  form, 
the  contents  of  a  hernial  sac. 

Hypogastric  region, — The  central  portion  of 
this  region  is  occupied  by  the  continued  con- 
volutions of  the  small  intestine.  The  right  iliac 
region  is  in  general  entirely  or  almost  entirely 
occupied  by  the  ccecum,  which  sometimes  has 
a  mesocoecum  and  sometimes  not.  In  the 
latter  case,  a  little  reticular  cellular  membrane, 
and  the  fascia  iliaca,  are  all  that  separate  the 
intestine  from  the  surface  of  the  iliacus  in- 
ternus  muscle.  Beneath  the  fascia  the  ilio- 
scrotal  and  the  inguino-cutaneous  nerves  are 
seen  passing  outwards  to  their  destination.  The 
internal  iliac  artery  and  vein  lie  along  the  inner 
margin  of  the  psoas  muscle,  covered  by  a  thin 
fibrous  expansion,  which  is  a  process  from  the 
iliac  fascia,  and  deeply  seated  between  the 
psoas  and  iliacus  internus  muscles  is  the  ante- 
rior crural  nerve.  The  external  iliac  arteries 
are  crossed  at  their  origin  by  the  ureters,  and 
along  their  course  a  few  glands  may  be  found 
either  at  the  sides  or  in  front.  This  region  is 
one  of  great  interest  to  the  pathologist,  in  con- 
sequence of  the  frequent  occurrence  of  disease 

*  Velpeau,  Anat.  Chir;  t.  ii.  p.  175. 
2  L 


50(5 


CAVITY. 


in  it,  whether  originating  in  the  wall  or  in  the 
coecum. 

There  is  no  part  of  the  intestinal  canal  in 
which  accumulations  are  more  likely  to  take 
place  than  in  the  coecum ;  and  it  is  now  pretty 
well  ascertained  by  the  researches  of  various 
observers  that  inflammation  is  often  pro- 
pagated from  the  ccecum  distended  with  har- 
dened faeces  to  the  cellular  tissue  and  muscles 
of  the  iliac  fossa,  thus  exciting  abscess,  which 
may  open  either  externally  through  the  abdo- 
minal parietes  or  internally  into  the  ccecum.* 
By  careful  manual  examination  of  the  anterior 
abdominal  wall  corresponding  to  this  fossa, 
we  are  in  general  able  to  detect  even  a  slight 
distension  of  the  ccecum,  and  percussion  em- 
ployed here  will  often  afford  considerable 
assistance  in  forming  a  diagnosis.  The  ver- 
miform appendix  of  the  ccecum  frequently 
hangs  down  into  the  pelvic  cavity  connected  to 
the  ceecum  by  a  fold  of  serous  membrane; 
at  other  times  it  lies  in  the  iliac  fossa,  being 
folded  up  under  cover  of  a  projecting  portion 
of  the  ccecum,  sometimes  as  a  natural  result, 
and  at  others  as  an  effect  of  morbid  adhe- 
sions. 

The  left  iliac  fossa  contains  the  sigmoid 
flexure  of  the  colon,  which  from  its  cylindrical 
form,  as  well  as  from  the  circumstance  of 
its  being  in  general  much  contracted,  does  not 
occupy  that  region  to  the  same  extent  as  the 
right  side  is  filled  by  the  ccecum.  The  sig- 
moid flexure  is  here  connected  by  a  mesocolon 
similar  to  that  of  the  descending  colon,  and 
its  relations  to  the  other  parts  contained  in  the 
iliac  fossa  are  pretty  much  the  same  as  those 
of  the  ccecum  on  the  right  side.  In  the  centre 
of  the  hypogastric  region  we  observe  that  the 
posterior  wall  is  formed  by  the  last  lumbar 
vertebra  and  the  promontory  of  the  sacrum, 
and  this  region  is  open  below,  whereby  it  com- 
municates with  the  pelvis  through  the  superior 
outlet.  Hence  along  the  posterior  wall  we  find 
the  rectum  with  its  mesorectum,  the  middle  sacral 
artery,  and  the  hypogastric  plexus  of  nerves ; 
and  some  of  the  pelvic  viscera  under  particular 
conditions  pass  forwards  into  this  region,  and 
even  admit  of  being  examined  during  life 
through  the  anterior  wall.  Thus  the  bladder 
under  distension  comes  forward,  and,  as  the 
distension  increases,  ascends,  so  as  often  to 
occupy  the  whole  of  this  region  to  the  ex- 
clusion of  its  natural  contents;  so  also  the 
uterus.  The  vas  deferens  in  the  male  and  the 
round  ligaments  of  the  uterus  in  the  female, 
and  in  both  the  obliterated  umbilical  arteries, 
the  urachus  and  the  spermatic  vessels,  are  also 
among  the  parts  belonging  to  the  hypogastric 
region. 

The  preceding  account  of  the  abdominal 
cavity  as  it  is  found  upon  dissection,  has  re- 
ference chiefly  to  the  adult  male  subject;  but 
there  are  certain  differences  in  the  relations  and 
positions  of  parts,  dependent  on  sex  and  age, 
to  which  it  is  highly  important  to  pay  due 

*  See  Dance  in  Rep.  Gen.  d'Anat.  et  de  Phys. 
t.  iv.  p.  74;  Meniere,  Arch.  Gen.  de  Med.  t.  xvii.; 
and  Ferrall,  Ed.  Med.  and  Surg.  Journal.  No.  108. 


attention.  In  the  adult  female,  the  chief  dif- 
ference arises  out  of  the  great  size  of  the  pelvis 
and  the  consequent  increase  in  the  magnitude 
of  the  lower  part  of  the  abdomen,  the  trans- 
verse measurement  of  which  will  be  found  to 
exceed  that  of  the  epigastric  region,  more 
especially  where  that  region  has  been  arti- 
ficially compressed  and  consequently  dimi- 
nished in  its  capacity,  by  the  custom  of  wear- 
ing tight  stays.  During  pregnancy,  which, 
as  being  a  natural  change,  may  be  not  inap- 
propriately noticed  here,  the  female  abdomen 
experiences  a  very  considerable  alteration  in 
its  form,  capacity,  direction,  the  relations  of  its 
organs,  and  the  order  of  its  circulation. 

"  In  the  first  month,"  says  Blandin,  "  it 
seems  to  contract,  and  its  walls  to  fall  in  upon 
themselves;  but  afterwards  opposite  changes 
take  place.  By  reason  of  the  resistance  offered 
by  the  pelvis,  when  the  uterus  begins  to  in- 
crease, and  especially  when  it  has  acquired  a 
certain  size,  it  makes,  as  it  were,  a  protrusion 
upwards,  and  is  carried  into  the  supra-pelvic 
part  of  the  abdominal  cavity,  which  it  dilates, 
especially  in  front,  in  consequence  of  which 
the  obliquity  of  the  axis  of  that  cavity  for- 
wards is  diminished.  The  dilated  uterus  is 
placed  entirely  in  front,  behind  the  anterior 
abdominal  wall,  and  presses  the  small  intestine 
and  omentum  towards  the  spine:  the  omen- 
turn,  however,  is  sometimes,  though  rarely, 
found  in  front  of  the  uterus.  The  diaphragm 
is  also  pushed  upwards  and  raised  as  high  as 
the  level  of  the  sixth  dorsal  vertebra :  all  the 
peritoneal  folds  of  the  uterus  are  obliterated  ; 
the  peritoneum  no  longer  descends  into  the 
pelvic  excavation,  the  bladder  and  the  rectum 
are  strongly  compressed,  and  are  in  some  de- 
gree impeded  in  performing  their  functions; 
the  uterus  itself  is  inclined  to  one  side,  in  con- 
sequence of  the  projection  of  the  vertebral 
column,  and  generally  to  the  right  side,  which, 
according  to  Chaussier,  is  attributable  to  the 
greater  shortness  of  the  round  ligament  of  the 
right  side.  Notwithstanding  all  this  enlarge- 
ment of  the  abdominal  cavity,  the  viscera  are 
compressed  more  strongly  than  usual,  and  can 
become  protruded  with  greater  facility,  when 
the  distended  and  attenuated  walls  have  lost 
much  of  their  power  of  resistance.  The  nor- 
mal irritation  of  which  the  uterus  is  the  seat, 
causes  a  greater  afflux  of  blood  into  the  whole 
inferior  part  of  the  vascular  system,  and  into 
its  own  vessels  in  particular."* 

During  the  development  and  growth  of  the 
walls  of  the  abdominal  cavity  some  interesting 
changes  are  observed  to  take  place  in  its  shape, 
capacity,  and  in  the  positions  of  the  contained 
viscera.  The  most  remarkable  characteristic  of 
the  abdomen  at  the  earliest  period  is  its  very 
great  capacity  when  compared  with  the  other 
cavities;  this  arises  from  the  great  development  of 
its  contained  organs.  This  great  size,  however, 
is  manifest  entirely  in  the  umbilical  region,  for 
neither  the  epigastric  nor  the  hypogastric  can 
be  said  to  exceed  their  proportional  magnitude 
in  the  adult.  On  the  contrary,  both  these 

*  Blandin,  Anat.  Topog.  p.  431. 


CAVITY. 


507 


regions  are  proportionally  much  smaller  than 
in  the  adult;  the  epigastric,  in  consequence  of 
the  contracted  diameters  of  the  thorax,  but  more 
particularly  in  consequence  of  the  small  size  of 
the  vault  which  is  formed  by  the  diaphragm  ; 
and  the  hypogastric  by  reason  of  the  imper- 
fectly developed  state  of  the  pelvis.  Hence, 
then,  we  find  that  most  of  the  viscera  extend 
more  or  less  into  the  middle  or  umbilical 
region,  which  thus  exhibits  a  very  great  en- 
largement. The  liver  is  the  viscus  which 
exhibits  the  most  remarkable  degree  of  enlarge- 
ment; its  two  lateral  lobes  present  but  little 
difference  in  size,  it  extends  laterally  so  as  to 
occupy  nearly  the  whole  epigastrium,  leaving 
but  a  small  space  at  the  left  side  for  the 
stomach  and  spleen;  it  passes  considerably 
beyond  the  inferior  margin  of  the  ribs,  so  that 
a  great  portion  of  it  is  found  in  the  umbilical 
region,  extending  even  to  the  hypogastrium. 
This  great  extent  of  space  occupied  by  the 
liver  necessarily  causes  corresponding  altera- 
tions in  the  positions  of  the  neighbouring  vis- 
cera, and  of  none  more  than  the  stomach.  The 
direction  of  this  organ  is  nearly  perpendi- 
cular, its  pyloric  extremity  is  found  a  little 
to  the  right  in  the  umbilical  region,  while 
the  aspect  of  its  splenic  end  is  upwards  and 
to  the  left;  its  great  curvature  looks  to  the 
left  side  and  downwards,  and  its  lesser  cur- 
vature to  the  right  and  upwards.  The  spleen 
is  not  altogether  contained  in  the  left  hy- 
pochondrium,  but  also  extends  into  the  left 
lumbar  region,  and  may  be  felt  below  the 
false  ribs.  The  duodenum  does  not  change 
its  positive  situation  with  reference  to  the 
spine,  but,  in  consequence  of  the  position  of 
the  stomach,  its  curves  are  more  marked,  the 
superior  portion  passes  more  decidedly  up- 
wards, and  the  whole  duodenum  is  to  a  greater 
extent  covered  by  the  stomach.  The  rest  of  the 
small  intestine  is  crowded  backwards  against 
the  spine,  and  in  consequence  of  the  non-deve- 
lopment of  the  pelvis  is  found  entirely  in  the 
umbilical  region ;  nor  is  it  covered  by  the 
omentum,  which  as  yet  has  attained  but  a  very 
small  size.  At  this  early  period,  moreover,  the 
bladder  is  an  abdominal  viscus;  in  general, 
very  capacious  and  of  a  cylindrical  form,  it 
extends  out  of  the  pelvis  to  within  a  very  short 
distance  of  the  umbilicus,  to  which  it  is  con- 
nected by  the  urachus,  so  that  it  occupies  a 
considerable  portion  of  the  hypogastric  and  a 
small  part  of  the  umbilical  regions ;  consequently. 
as  Portal  remarks,  the  shortest  route  by  which 
the  bladder  can  be  reached  at  this  early  age  is 
according  to  the  method  of  the  suprapubic 
operation,  and  it  is  only  a  small  portion  of  the 
neck  of  the  bladder  which  is  at  all  in  relation 
with  the  perinaeum.  A  considerable  portion  of 
the  rectum,  also,  is  found  in  the  hypogastrium, 
and  in  the  female  the  uterus  and  ovaries  and 
the  Fallopian  tubes.  Prior  to  the  seventh  or 
eighth  month  of  intra-uterine  life,  when  the  tes- 
ticles enter  the  scrotum,  they  are  found  suc- 
cessively as  they  descend  in  different  regions  of 
the  abdominal  cavity,  at  first  in  the  lumbar 
regions  immediately  beneath  the  kidneys,  and 
then  at  different  heights  along  the  inner  side  of 


the  iliac  fossae ;  we  also  observe  here  that  pro- 
cess of  peritoneum  connected  with  the  testicle, 
and  extending  from  it  to  the  inguinal  canal, 
which  is  known  by  the  name  of  the  diver ticu- 
lum  of  Nuck :  a  similar  process  exists  in  a 
much  less  developed  condition  in  the  female 
connected  with  the  round  ligament.  The  prin- 
cipal difference  observable,  as  regards  the  large 
intestine  in  the  fetus  at  its  full  period,  consists 
in  the  great  curvature  of  that  portion  of  it  that 
is  found  iii  the  left  iliac  region,  occasioned  by 
the  narrowness  of  the  pelvis  admitting  but  a 
small  part  of  the  rectum.*  In  the  progressive 
development  which  takes  place  during  intra- 
uterine  life,  the  position  of  this  as  well  as  of  the 
other  portions  of  the  intestinal  canal  presents  dif- 
ferences which  it  does  not  belong  to  the  present 
article  to  examine.  (See  INTESTINAL  CANAL.) 

The  capacity  of  the  abdominal  cavity  and 
the  position  of  some  of  its  contained  organs, 
as  they  thus  exist  in  the  fetus  at  its  full  period, 
continue  pretty  nearly  the  same  for  some  time 
after  birth.  The  enlargement,  however,  of  the 
vault  of  the  diaphragm  increases  the  capacity 
of  the  epigastrium,  while  the  gradual  diminu- 
tion of  the  liver  affords  room  for  the  passage 
of  more  organs  from  the  umbilical  region  up- 
wards, and  the  stomach  is  allowed  to  take  a 
more  horizontal  direction.  These  changes, 
which  are  gradual  in  the  periods  of  life  prior 
to  puberty,  become  most  manifest  when  the 
arrival  of  that  period  gives  rise  to  the  enlarge- 
ment of  the  pelvis  ;  then  the  umbilical  region 
is  as  it  were  relieved  from  its  overloaded  state ; 
the  belly  is  less  prominent,  for  the  bladder 
now  occupies  its  proper  place  in  the  pelvic 
cavity;  the  rectum,  too,  sinks  into  it,  and  many 
of  the  convolutions  of  the  small  intestine  are 
found  in  it:  thus,  by  the  enlargement  of  the 
hypochondria  in  the  first  instance,  and  subse- 
quently by  the  development  of  the  pelvis,  the 
three  subdivisions  of  the  abdominal  cavity 
assume  those  proportions  in  their  respective 
magnitudes  which  are  characteristic  of  the 
adult  period. 

In  considering  the  probable  amount  of  in- 
jury inflicted  by  wounds  which  may  have  pene- 
trated the  abdominal  cavity,  we  must  take  into 
account  the  changes  which  the  different  atti- 
tudes of  the  body  occasion  in  the  positions  of 
the  viscera.  These  changes  cannot  be  exten- 
sive, and  only  regard  the  position  of  each 
viscus  with  reference  to  the  whole  cavity,  the 
relations  of  that  viscus  to  the  neighbouring 
ones  being  unaltered,  or  nearly  so.  They  take 
place  in  obedience  to  the  law  of  gravitation, 
and  it  is  so  easy,  by  a  little  reflection,  to  de- 
duce what  the  changes  must  be,  keeping  in 
mind  the  various  means  made  use  of  to  limit 
and  prevent  displacement,  that  it  seems  unne- 
cessary to  do  more  here  than  allude  to  the  fact 
that  the  viscera  are  altered  in  position  under 
the  influence  of  such  a  cause. 

ABNORMAL  CONDITIONS  OF  THE  ABDOMI- 
NAL CAVITY. — All  the  abnormal  conditions  of 

*  See  on  this  subject  Portal,  Anat.  Med.  torn.  v. 
Blandin,  Anat.  Topog.  and  Meckel,  Anat.  Gen. 
Dcsc.  et  Path.  torn.  iii. 

2  L  2 


508 


CAVITY. 


the  abdomen  may  be  considered  under  two 
heads :  1 .  as  they  regard  the  parietes  of  the 
cavity;  and,  2.  as  they  refer  to  the  positions  of 
the  contained  organs.  We  shall  first  examine 
the  abnormal  conditions  of  the  parietes. 

Congenital  malformations  of  the  abdominal 
parietes. — The  first  class  of  these  malformations 
which  demands  consideration  is  that  which  de- 
pends on  a  defect  in  the  development  of  the 
structures  which  form  the  abdominal  walls,  and 
these  are  by  far  the  most  numerous.  In  ex- 
amining them  it  is  to  be  borne  in  mind  that 
many  of  the  abdominal  viscera  exist  before  the 
walls  of  the  cavity,  which  are  formed  around 
the  viscera,  and  that  the  anterior  wall  is  later  in 
its  formation  than  any  of  the  others.  The  ca- 
vity containing  the  viscera  seems  at  first  to  be 
a  continuation  of  that  of  the  umbilical  cord, 
its  walls  being  continued  from  the  sheath  of 
the  cord.  A  distinct  separation  does  not  appear 
to  take  place  until  the  skin  has  become  deve- 
loped, when  a  line  of  demarcation  is  evident 
between  the  skin  of  the  abdomen  and  the 
sheath  of  the  cord. 

The  anterior  wall  may  be  deficient  on 
both  sides  to  a  greater  or  less  extent,  the 
lateral  and  posterior  being  also  more  or  less 
involved.  The  maximum  is  when  the  defect 
extends  not  only  throughout  the  whole  anterior 
abdominal  wall,  but  also  to  that  of  the  thorax, 
leaving  all  the  viscera  of  both  abdomen  and 
thorax  visible,  being  covered  only  by  a  thin 
membrane ;  and  frequently  congenital  deficien- 
cies of  the  lower  part  of  the  anterior  wall  of  the 
thorax  are  accompanied  by  a  more  or  less  ex- 
tensive defect  of  the  upper  part  of  the  same 
wall  of  the  abdomen,  and  the  heart  is  included 
with  the  abdominal  viscera,  which  are  rendered 
visible,  and  which,  in  some  instances,  protrude 
forwards.  There  may,  however,  be  a  con- 
genital deficiency  of,  or  fissure  in  the  deeper 
seated  elements  of  the  anterior  abdominal  and 
thoracic  wall,  and  yet  the  skin  remain  per- 
fect and  cover  the  protruded  viscera.*  But 
the  thoracic  parietes  may  be  perfect,  and  yet 
there  may  exist  an  imperfect  condition  of  the 
abdominal  parietes  to  a  greater  or  less  extent, 
which  imperfection  evidently  results  from  the 
continuance  of  a  greater  or  less  portion  of  the 
abdominal  wall  in  that  condition  in  which  it 
naturally  exists  in  the  early  stages  of  fetal 
development.  In  such  cases  the  viscera  are 
covered  by  an  expansion  which  is  continuous 
with  the  sheath  of  the  umbilical  cord.  When 
the  deficiency  of  the  abdominal  wall  exists  to 
a  great  extent,  the  tumour  formed  by  the  pro- 
truding viscera  is  designated  by  the  term  even- 
tration ;  but  if  the  defect  be  very  limited,  and 
exist,  as  it  generally  does,  at  the  base  of  the 
umbilical  cord,  then  the  protrusion  is  an  exom- 
phalos  or  congenital  umbilical  hernia.  Both, 
as  Isidore  Geoffrey  St.  Hilaire  remarks,  are 
results  of  an  arrest  in  the  development  of  the 
abdominal  walls,  with  this  difference,  that  in 
the  former  the  cessation  of  development  takes 

*  See  Geoffrey  St.  Hilaire's  description  and  plate 
of  an  hyperenceohalous  foetus  :  Monstruosites 
Hnmaines,  pp.  183  &  seqq.  plate  15. 


place  at  an  early  period  of  foetal  existence,  but 
in  the  latter  at  a  late  period.  In  conformity 
with  the  same  laws,  under  the  influence  of 
which  the  arrest  of  development  took  place, 
we  find  that,  as  in  the  progress  of  the  natural 
formation,  the  small  intestine  is  the  last  to 
enter  the  abdominal  cavity,  so  a  larger  or 
smaller  portion  of  that  intestine  is  generally 
found  in  the  tumour  of  a  congenital  exom- 
phalos.  The  nature  of  the  contents  of  an 
eventration  depends  evidently  on  the  extent  of 
the  deficiency  and  the  region  of  the  abdomen 
which  is  most  involved. 

In  some  instances  the  peritoneum  is  deficient 
to  an  extent  corresponding  to  that  of  the  defi- 
ciency of  the  abdominal  parietes.  This  is  a 
rare  occurrence,  and  is  generally  met  with  where 
the  defect  of  development  is  very  extensive.* 
There  are  cases,  however,  where,  although  the 
defect  was  small,  the  peritoneum  was  absent 
to  a  corresponding  extent,  and  the  intestines 
protruded  through  the  opening  in  a  naked 
state.f 

The  congenital  inguinal  hernia  must  likewise 
be  referred  to  an  arrest  in  the  development 
of  a  very  small  portion  of  the  anterior  abdo- 
minal wall.  The  canal  of  communication 
which  at  one  period  exists  between  the  peri- 
toneal sac  and  the  sac  of  the  tunica  vaginalis 
remains  pervious,  the  natural  process  by  which 
it  is  closed  having  been  arrested.  This  mode 
of  explaining  the  formation  of  congenital  bubo- 
nocele does  not  preclude  the  possibility  of  its 
accidental  occurrence,  the  material  which  closes 
the  canal  having  given  way  under  the  influence 
of  some  force  applied  to  it. 

The  superior  wall  of  the  abdomen  sometimes 
presents  a  defect  of  development,  giving  rise 
to  the  congenital  perforation  of  the  diaphragm, 
through  which  herniae  take  place  into  the 
thorax.  Such  a  perforation  may  exist  on  either 
side,  although  it  is  much  more  frequently 
found  upon  the  left.  (See  DIAPHRAGM.) 

The  malformation  commonly  known  under 
the  name  of  '  extroversion  of  the  bladder,'  has 
also  connected  with  it  an  imperfect  state  of  the 
anterior  abdominal  wall  interiorly,  in  conse- 
quence of  the  separation  of  the  ossa  pubis  and 
of  the  recti  abdominis  muscles,  and  I  be- 
lieve, in  general,  the  absence  of  the  pyrami- 
dales.  (See  BLADDER,  ABNORMAL  ANATOMY.) 
In  these  cases  the  umbilicus  is  generally  situ- 
ated much  lower  than  usual,  and  some  writers 
have  fallen  into  the  absurd  error  of  supposing 
that  it  was  absent  altogether,  in  consequence 

*  See  a  case  by  Ruysch,  (observat.  Ixxii.) 
in  which  the  stomach,  intestines,  and  spleen  were 
situated  externally  to  the  cavity  of  the  abdomen. 
Also  one  by  Robinson,  in  which  the  defect  ex- 
tended from  the  abdomen  to  the  umbilicus.  Amer. 
Journal  of  Med.  Sc.  Feb.  1833,  p.  346;  and  a  very 
interesting  and  well-narrated  one  by  my  learned 
friend  Dr.  Montgomery,  in  the  Trans.  Coll.  Phys. 
Dub.  vol.  i.  New  Series.  See  also  several  other  cases 
referred  to  in  Meckel,  Handbuch  Der  Pathol. 
Anatomie,  Band.  i.  p.  97 — 139. 

t  See  Fried,  de  ftstu  intestinis  plane  nudis  extra 
abdomen  propendentibus  nato,  in  SandifortThesaur. 
dissert,  t.  i.  Also  Howell,  in  London  Med.  and 
Phys.  Journal,  vol.  xlv.  1821. 


CELLULAR  TISSUE. 


509 


of  its  having  escaped  their  notice  by  being 
covered  and  concealed  by  the  protruded  blad- 
der. 

A  second  class  of  congenital  malformations 
of  the  abdominal  parietes  arises  from  an  excess 
in  the  development  of  certain  parts,  as  a  nu- 
merical increase  in  the  muscles,  vessels,  or 
nerves  entering  into  the  formation  of  the  abdo- 
minal parietes,  or  from  the  development  of  a 
part  of  a  second  foetus  in  connexion  with  the 
abdomen.  Of  the  former  it  is  extremely  rare 
to  meet  with  instances  among  the  muscles  or 
vessels  of  the  abdomen ;  occasionally  we  do 
find  an  unimportant  increase  in  the  number  of 
the  costal  attachments  of  one  or  more  of  the 
muscles.  As  to  the  latter  several  cases  are 
recorded  in  which  foetuses  exhibited  an  arm  or 
leg,  or  even  a  portion  of  the  trunk  of  another 
implanted  upon  the  abdominal  wall,  or,  as  is 
a  very  rare  occurrence,  included  in  it;  con- 
stituting a  subdivision  of  that  form  of  mon- 
strosity which  has  been  called  Diplogenesis. 
We  refer  to  the  article  MONSTROSITY  for  details 
on  this  subject. 

Morbid  conditions  of  the  abdominal  parietes. 
— These  are  such  as  are  common  to  all  parts 
compounded  of  the  same  elements  as  enter  into 
the  formation  of  the  abdominal  walls,  which 
it  would  be  superfluous  to  particularise  here. 

Congenital  malformations  of'  the  abdominal 
cavity. — In  many  acephalous  fetuses  the  ab- 
dominal cavity  is  more  or  less  curtailed  of  its 
due  proportions,  the  deficiency  existing  at  its 
superior  part.  Where  the  inferior  part  of  the 
thorax  or  the  pelvis  is  malformed,  the  abdo- 
minal cavity  will  also  be  necessarily  more  or 
less  affected. 

Under  this  head  we  may  refer  to  the  ano- 
malies which  arise  from  the  congenital  mal- 
position of  the  viscera,  which  may  extend  to 
the  whole  contents  of  the  abdomen,  or  may 
affect  only  one  or  more  viscera.  Such  are  the 
cases  of  complete  transposition  of  the  viscera, 
where  those  which  in  the  normal  state  are  on  the 
right  side  are  found  upon  the  left,  and  vice  versa; 
thus  the  liver  is  found  on  the  left,  the  pylorus 
on  the  left,  the  cardiac  extremity  of  the  sto- 
mach and  the  spleen  on  the  right,  &c.  &c. 
The  aorta  and  vena  cava  too  change  places,  and 
the  openings  in  the  diaphragm  alter  their  po- 
sitions along  with  the  parts  which  respectively 
pass  through  them.  The  same  transposition 
generally  extends  also  to  the  thoracic  viscera. 
In  many  of  the  instances  in  which  this  trans- 
position has  been  observed,  the  individuals  have 
lived  to  the  adult  period  of  life  without  ex- 
hibiting any  symptom  indicative  of  the  unusual 
position  of  the  internal  organs.* 

Single  viscera  are  likewise  often  found  trans- 
posed or  in  unusual  positions,  occasioning 
necessarily  corresponding  changes  in  the  parts 
which  are  connected  with  them.  It  is  unne- 
cessary to  allude  further  to  them  here,  as  they 

*  See  Metzger  de  Translocatione  Viscerum,1779 ; 
also  instances  in  Haller,  Op.  Minora,  t.  iii.  ;  and 
several  cases  of  modern  date,  of  which  one  of  the 
most  complete  is  that  published  by  Bryan  in  the 
Transactions  of  the  Irish  College  of  Physicians, 
vol.  iv. 


will  be  treated  of  in  the  articles  appropriated 
to  those  viscera. 

The  morbid  conditions  of  the  abdominal 
cavity  are  the  results  of  disease  affecting  its 
lining  membrane  or  its  contained  viscera  and 
other  parts  intimately  connected  with  it.  See 
PERITONEUM  and  INTESTINAL  CANAL. 

For  the  Bibliography  see  that  of  ABDOMEN  and 
INTESTINAL  CANAL. 

( R.  B.  Todd.) 


CELLULAR  TISSUE.—  Tela  cellulosa, 
textus  mucosus,  corpus,  cribrosum,  cellular  mem- 
brane, reticular  membrane,  filamentous,  areolar, 
laminar  tissue,  &c.  (Fr.  tissu  celluleux ;  Germ. 
Zellgeweben.)  The  cellular  tissue  is  the  most 
universally  diffused  element  of  organization, 
and  constitutes  the  basis  of  every  animal  body. 
It  consists  of  a  soft,  areolated,  and  elastic  sub- 
stance. A  somewhat  similar  structure  also 
exists  in  vegetables,  constituting  their  most 
simple  or  elementary  texture. 

In  systematic  works  the  cellular  tissue  is 
generally  considered  as  a  solid  substance ;  but 
as  it  really  exists  in  the  animal  body,  it  is  a 
compound  of  solid  and  fluid  materials ;  for  in  no 
part  of  any  animal  is  the  cellular  membrane 
ever  entirely  devoid  of  fluid.  This  union  of 
fluid  and  solid  parts  is  indeed  indispensable  to 
organization,  since  there  is  no  animal,  or  even 
vegetable,  in  which  it  may  not  be  demonstrated. 
In  the  zoophyte  the  entire  body  appears  to 
consist  of  the  cellular  tissue,  and  even  in  man 
it  enters  so  largely  into  the  formation  of  the 
different  organs,  pervading  equally  the  most 
delicate  and  the  most  solid  parts,  that  it  con- 
stitutes a  species  of  mould  of  the  whole  body 
and  of  its  individual  parts ;  indeed,  if  we  ex- 
cept the  enamel  of  the  teeth,  and,  as  some 
authorities  contend,  also  the  nails,  the  hairs, 
and  the  epidermis,  there  is  no  solid  in  which  it 
may  not  be  detected. 

Many  anatomists  have  included  the  adipose 
tissue  under  the  general  denomination  of  cel- 
lular membrane,  but  as  the  vesicles  of  the 
former  are  distinct  from  the  cells  of  the  latter, 
both  as  regards  their  formation  and  the  nature 
of  their  contents,  we  rather  incline  to  adopt  the 
views  of  Malpighi,  W.  Hunter,  Beclard,  and 
others,  who  contend  that  the  adipose  and  cellu- 
lar tissues  are  distinct  and  separate  structures. 
(See  ADIPOSE  TISSUE.) 

Arrangement. — The  most  striking  and  im- 
portant fact  relative  to  the  cellular  tissue  is  its 
uninterrupted  continuity  throughout  the  whole 
body,  there  being  no  part  or  region,  however 
insulated  it  may  appear  to  be,  in  which  this 
communication  may  not  be  demonstrated. 
Whilst  we  fully  admit  this  general  communica- 
tion, it  is  yet  necessary  to  state  that  the  cellular 
tissue  may  be  appropriately  divided  into  two 
parts :  the  first  division,  called  from  its  dis- 
position the  common  or  interstitial  portion 
(textus  cellularis  intermedius  vel  laxw),  is  that 
which  occupies  the  spaces  left  between  the 
various  organs  in  all  parts  of  the  body ;  the 
second  division  is  distinguished  by  the  name 
of  the  special  cellular  membrane  (t.  cellularis 


510 


CELLULAR  TISSUE. 


strictw,  t.  ccllularis  stipatus),  because  it  is 
proper  to  the  several  constituent  parts  of  the 
body,  investing  each  of  them,  and  penetrating 
into  their  internal  structure. 

Of  the  common  cellular  membrane. — It  is  in 
this  division  that  the  connection  to  which  we 
have  just  referred  is  most  free.  Thus  in  the 
subcutaneous  tissue  placed  between  the  skin 
and  the  fasciae  of  the  muscles,  there  is  an  uni- 
versal and  evident  communication.  Again, 
in  the  head,  the  cellular  membrane  of  the  exter- 
nal parts  communicates  with  that  of  the  internal 
through  all  the  natural  apertures — through  the 
foramina  of  the  base  and  other  regions  of  the 
skull.  From  the  face  and  cranium  the  con- 
nexion may  readily  be  traced  to  the  neck, 
whence,  after  having  pervaded  all  its  parts,  it 
passes  in  one  direction  behind  the  ,  sternum 
and  upper  ribs  to  the  thoracic  cavity ;  and  in 
another  underneath  the  clavicle  and  scapula  on 
either  side,  to  the  arm-pit,  which  may  be  re- 
garded as  the  common  point  of  junction  be- 
tween the  cellular  substance  of  the  neck,  the 
trunk,  and  upper  extremity. 

The  cellular  tissue  of  the  thorax  is  continuous 
with  that  of  the  abdomen  through  the  openings 
of  the  diaphragm,  and  particularly  beneath  the 
sternum,  around  the  aorta,  the  inferior  vena 
cava,  and  the  oesophagus.  In  a  similar  manner 
the  connexion  may  be  followed  from  the  abdo- 
men to  the  pelvis ;  from  the  former  of  these 
cavities  under  the  crural  arch  to  the  inguinal 
region,  which  constitutes  the  point  of  union 
between  the  trunk  and  the  lower  extremity; 
whilst  from  the  pelvis  the  communication  ex- 
tends in  one  direction  by  the  side  of  the  rectum 
and  urethra  to  the  perineum,  scrotum,  and 
penis ;  and  in  another  by  the  obturator  fora- 
men and  the  ischiatic  notch  to  the  thigh. 

In  addition  to  these,  which  are  the  principal 
connexions,  the  common  cellular  membrane  is 
united  in  every  direction  with  the  special  di- 
vision ;  the  details,  however,  of  these  commu- 
nications belong  to  the  descriptive  anatomy  of 
the  several  regions,  to  the  articles  on  which'the 
reader  is  referred. 

The  quantity  of  the  interstitial  tissue  varies 
according  to  the  age  and  temperament  of  the 
individual,  and  to  the  region  of  the  body  in 
which  it  is  examined;  but,  independently  of 
any  original  differences  which  exist,  it  is  well 
known  that  the  mode  of  living  and  habits  of  the 
individual  have  a  great  influence  in  this  respect : 
thus  an  habitual  full  diet,  especially  if  con- 
joined with  indolence,  causes  a  great  accumu- 
lation of  the  cellular  substance ;  whilst,  on  the 
contrary,  a  spare  or  moderate  diet  and  exercise 
will  reduce  it  in  a  remarkable  degree.  These 
differences  depend,  probably,  more  on  the  accu- 
mulation of  serous  fluid  and  on  the  repletion  of 
the  bloodvessels,  than  on  the  actual  increase 
of  the  proper  filamentous  tissue  :  we  can  in  this 
manner,  and  in  no  other,  understand  how,  by 
by  what  in  England  is  called  training,  the  bulk 
of  the  body  may  be  so  rapidly  diminished. 

The  proportion  of  this  tissue  varies  also  in 
the  different  regions  of  the  body ;  but  as  it  is 
in  an  especial  manner  subservient  to  the  pro- 
duction of  free  motion,  it  is  principally  accu- 


mulated in  those  parts  which  are  most  move- 
able.  It  is  on  this  account  that  it  abounds  on 
the  face,  especially  around  the  globe  of  the  eye 
and  about  the  cheeks,  and  also  on  the  forepart 
of  the  neck  and  of  the  trunk  in  general.  In  the 
limbs  it  is  met  with  in  considerable  quantity  in 
the  flexures  of  the  joints,  in  the  axilla,  the 
elbow,  the  wrist,  and  in  the  palm  of  the  hand; 
also  in  the  groin,  in  the  ham,  in  the  front  of  the 
ankle,  and  in  the  sole  of  the  foot.  The  super- 
ficial muscles,  which  are  very  moveable,  are 
separated  from  each  other  by  thicker  layers  of 
membrane  than  the  deeper-seated  and  more 
fixed.  It  may  also  be  remarked  that  those 
important  organs,  which  are  most  liable  by  their 
structure  or  connexions  to  rupture  or  other 
effects  of  external  violence,  are  carefully  pro- 
tected by  being  lodged  in  a  large  quantity  of 
cellular  substance.  It  is  thus  that  we  find  the 
pancreas  and  the  kidneys  enveloped  in  this 
tissue  in  the  abdomen ;  the  bladder  and  genital 
organs  in  the  pelvis ;  and  the  bloodvessels  and 
nerves  in  all  parts  of  the  body. 

Of  the  special  cellular  membrane.  —  Each 
organ  in  the  body  is  invested  in  a  proper  cover- 
ing of  the  cellular  tissue,  and  also  receives  into 
its  interior,  processes  which  envelope  and  join 
together  its  component  parts. 

The  investing  cellular  membrane  (t.  cellu- 
laris  strictus)  is  united  by  one  of  its  surfaces, 
the  external,  with  the  general  cellular  tissue, 
and  by  the  other  or  internal  with  that  entering 
into  the  organ.  It  presents  many  peculiarities 
as  to  the  mode  of  its  connexion  ;  the  solid 
parts,  for  instance,  as  the  glands,  muscles,  and 
nerves,  are  entirely  surrounded  by  cellular 
envelopes ;  and  a  somewhat  similar  disposition 
is  observed  around  the  bloodvessels,  lympha- 
tics, and  excretory  tubes.  On  the  contrary, 
the  skin,  the  mucous  and  serous  membranes, 
having  one  surface  free  or  unattached,  are  only 
connected  on  one  side  with  the  cellular  tissue, 
which  is  distinguished  according  to  its  situation, 
by  the  terms  subcutaneous,  submucous,  and 
subserous  cellular  tissue.  The  covering  thus 
afforded  to  each  individual  organ  serves  in  a 
certain  degree  to  insulate  and  separate  it  from 
the  surrounding  structures,  and  in  this  manner 
it  often  tends  to  limit  the  progress  of  disease; 
but  as  we  have  just  seen  that  this  covering  is 
united  both  to  the  interstitial  and  to  the  pene- 
trating cellular  tissue,  it  would  be  equally  con- 
trary to  reason  and  experience  to  expect  that  it 
should  constitute,  as  some  authorities  have  con- 
tended that  it  does,  a  species  of  atmosphere 
around  the  various  organs,  confining  their  natu- 
ral actions  and  morbid  phenomena. 

The  penetrating  cellular  tissue  (t.  cellularis 
stipatus)  constitutes  so  essential  a  part  of 
organized  structures,  that  there  is  no  organ  in 
which  it  may  not  be  detected.  It  exists  in 
the  substance  of  bone,  cartilage,  and  ligament, 
although  it  is  distinguished  in  these  structures 
with  difficulty,  in  consequence  of  their  great 
density ;  it  penetrates  between  the  most  minute 
fibres  of  the  muscles  and  nerves;  between  the 
coats  of  the  bloodvessels  and  lymphatics  ;  also 
between  the  layers  composing  the  skin  and 
mucous  membranes ;  and  lastly,  it  enters  into 


CELLULAR  TISSUE. 


510 


the  substance  of  the  absorbent  and  secreting 
glands,  investing  their  several  component  parts. 

Structure  and  organization. — If  a  portion  of 
cellular  tissue  void  of  adipose  substance  be  ex- 
amined with  the  naked  eye,  and  for  this  purpose 
that  which  intervenes  between  very  recent  muscu- 
lar fibres  may  be  advantageously  selected,  it  will 
be  seen  that  it  is  composed  of  an  immense  num- 
ber of  delicate  and  semi-transparent  filaments, 
having  very  much  the  appearance  of  the  finest 
threads  of  a  spider's  web.  These  fibrils  cross 
each  other  in  various  directions,  and  in  this 
manner  intercept  innumerable  spaces,  which 
communicate  one  with  another,  and  exhibit  a 
vast  variety  of  figures.  The  small  spaces  or 
areolae  which  are  thus  produced  constitute  what 
are  called  the  cells  of  this  tissue ;  but  as  there 
is  nothing  determinate  either  in  their  size  or 
shape,  which  evidently  vary  according  to  ihe 
degree  of  traction  exercised  in  separating  the 
filaments ;  as  they  communicate  together,  and 
consequently  are  not  circumscribed ;  as  they 
are  in  fact  simply  the  interstices  left  between 
the  fibres,  the  expression  in  common  use  is 
calculated  to  convey  an  erroneous  idea  of  the 
real  nature  of  these  spaces. 

If  the  investigation  be  prosecuted  with  the 
aid  of  a  powerful  microscope,  a  very  beautiful 
appearance  will  be  presented,  of  which  it  is 
impossible  to  convey  an  adequate  idea  by  any 
description.  We  shall  still  observe  fibres  cross- 
ing in  all  directions  ;  but  although  I  have  had 
many  favourable  opportunities  of  making  these 
observations,  I  have  never  been  able  to  detect 
in  the  cellular  fibre  that  linear  arrangement  of 
globules  described  by  Dr.  Milne  Edwards,  and 
which  has  of  late  years  been  very  generally 
supposed  to  pervade  all  the  elementary  fibres  of 
the  body.  A  number  of  globular  particles  may, 
it  is  true,  be  seen  at  irregular  distances,  either 
clustered  together  or  dispersed  in  an  isolated 
manner,  but  they  do  not  enter  into  the  forma- 
tion of  the  fibre.  The  results,  then,  of  careful 
inspection  disprove  the  ideas  of  former  anato- 
mists, some  of  whom,  Ruysch  and  Mascagni 
for  example,  supposed  that  the  cellular  fibre 
was  entirely  vascular,  whilst  others  imagined 
it  to  be  an  expansion  of  the  nerves :  it  is  now 
generally  admitted  that  the  basis  of  the  cel- 
lular substance  is  a  solid  and  elementary  fibre ; 
and  although  to  the  naked  eye  it  often  presents 
a  membranous  form,  yet  microscopical  observa- 
tion evinces  that  the  plates  of  membrane  are 
distinctly  composed  of  solid  fibres.  The  in- 
terstices or  cells  always  contain  in  health  a 
very  thin  albuminous  fluid,  which  has  a  great 
resemblance  to  the  secretion  of  the  serous  mem- 
branes, and  also  to  the  serum  of  the  blood ; 
and  hence  it  is  often  termed  the  cellular  serosity. 
This  fluid,  which  must  be  regarded  as  an  in- 
tegrant part  of  this  tissue,  has  a  great  influence 
on  its  properties,  so  that  if  it  be  entirely  re- 
moved, as  by  desiccation,  the  membrane  be- 
comes hard  and  brittle,  and  its  elasticity  is 
almost  lost ;  or  if  it  be  accumulated  in  excess, 
as  we  often  see  it  in  disease,  the  elastic  force  is 
also  destroyed. 

Bloodvessels   and   lymphatics. — An    inquiry 
into  the  relations  which  exist,  between  the  cel- 


lular and  vascular  tissues,  would  lead  to  the 
important  question,  how  far  vascularity  is  essen- 
tial to  organization?  Without  entering  into 
this  investigation,  it  may  be  remarked  that  the 
cellular  substance  is  provided  with  blood- 
vessels; and  although  the  greater  number  of 
these  merely  traverse  the  membrane  in  order  to 
reach  other  parts,  yet  the  phenomena  of  nutri- 
tion and  absorption  shew  that  a  vascular  appa- 
ratus must  exist  in  connexion  with  the  cellular 
tissue. 

Nerves. — It  is  impossible  to  trace  any  ner- 
vous filaments  to  the  cellular  fibres,  although 
such  threads  may  be  seen  passing  between  them 
to  the  neighbouring  organs.  The  insensibility 
in  its  healthy  state  also  seems  to  indicate  the 
absence  of  nerves;  but  as  pain  is  experienced 
during  inflammation,  we  must  admit  the  ex- 
istence of  some  communication  with  the  senso- 
rium. 

Chemical  composition. — The  cellular  sub- 
stance contains,  like  all  the  soft  solids  of  the 
body,  a  large  quantity  of  water :  when  this  is 
evaporated,  the  fibres  and  cells  adhere  to  each 
other,  and  present  a  membranous  appearance. 
Analysis  shews  that  albumen  and  gelatine  com- 
pose this  substance ;  the  former  predominating, 
and  being  in  a  state  of  coagulation,  bestows 
on  it  the  necessary  degree  of  firmness  and  re- 
sistance. 

Properties. — As  we  shall  have  occasion  in 
a  future  article  (see  MEMBRANE)  to  consider 
this  subject  more  minutely,  it  will  suffice  if  we 
here  remark  that  the  most  important  property 
of  the  cellular  substance  is  a  species  of  contrac- 
tion which  produces  in  all  the  soft  parts  a  con- 
stant state  of  tension  or  tone,  which  is  one  of 
the  most  remarkable  qualities  of  living  bodies. 
The  cause  of  this  peculiar  condition,  "in  what- 
ever part  it  is  evinced, — in  the  skin,  in  the 
cellular  tissue,  in  the  muscles,  in  the  vessels, 
&c. — is  the  result  of  a  property  inherent  in  mem- 
branous matter,  which  some  authorities  refer  to 
muscular  contractility,  and  others  to  elasticity  ; 
whilst  many  eminent  physiologists,  denying 
both  these  hypotheses,  conceive  that  the  con- 
traction to  which  we  are  alluding  is  of  a 
character  sui  generis,  and  which  they  have 
called  tonicity,  vis  cellulosa,  tonic  contraction, 
contractility  of  tissue,  &c.  I  confess  that  none  of 
these  theories  have  ever  been  to  me  satisfactory ; 
because,  as  regards  the  first,  there  is  no  resem- 
blance between  the  phenomena  connected  with 
the  contraction  of  membranous  parts,  and  those 
of  muscular  contraction  ;  whilst,  as  respects  the 
second,  the  resiliency  by  which  the  skin  re- 
covers itself  after  pressure  has  been  made  on 
the  external  surface,  and  the  retraction  and 
separation  of  the  sides  of  an  incision  inflicted 
on  the  integument,  being  observed  only  during 
life,  and  never  after  death,  prove  that  the  results 
of  cellular  contraction  are,  in  some  important 
respects,  different  from  those  of  common  elas- 
ticity. Those  writers  who,  in  consequence  of 
the  difficulty  of  referring  the  phenomena  under 
consideration  to  either  of  the  known  causes  of 
contraction,  viz.,  muscular  contractility  and 
elasticity,  have  imagined  the  existence  of  a  new 
kind  of  contractile  power,  have,  without  ad- 


512 


CELLULAR  TISSUE. 


ducing  any  sufficient  proof  in  corroboration  of 
their  views,  had  recourse  to  an  expedient  but 
too  frequently  adopted  by  physiologists  when 
the  real  nature  of  any  vital  process  escapes  their 
detection. 

The  only  way  in  which  the  apparently  con- 
tradictory results  of  experiment  and  observation 
can  be  reconciled,  is  by  attending  to  a  combina- 
tion of  vital  and  physical  processes,  that  has 
been  too  much  neglected  in  investigating  the 
characters  of  living  bodies ;  that  is  to  say,  it 
must  be  recollected  that  "  life,"  to  borrow  the 
philosophic  expression  of  Dr.  Arnott,*  "  is  a 
superstructure  on  physics  and  chemistry,"  and 
that  those  phenomena  which  are  essentially  de- 
pendent on  the  ordinary  laws  of  matter  are 
controlled  and  modified  by  the  superior  prin- 
ciple of  life.  In  the  case  of  the  cellular  sub- 
stance this  remark  is  peculiarly  applicable ;  and 
from  reflecting  on  all  the  facts  relative  to  that 
tissue  both  in  a  state  of  health  and  disease, 
I  have  arrived  at  the  conclusion  that  the  phe- 
nomena of  its  contractile  force  are  the  com- 
bined results  of  one  of  the  common  proper- 
ties of  matter,  viz.,  elasticity;  and  of  a  vital 
process,  viz.,  nutrition.  It  is  a  well-known 
fact  that  the  existence  of  elasticity  in  any  inor- 
ganic substance  requires  a  particular  state  or 
arrangement  of  its  particles,  and  that  if  the 
necessary  condition  be  but  partly  fulfilled,  or 
be  entirely  wanting,  that  property  is  only 
slightly  displayed,  or  is  totally  absent.  The 
same  principle  strictly  applies  to  the  living 
body;  and  in  the  cellular  substance  the  required 
condition  is,  a  definite  proportion  between  the 
solid  fibres  and  the  interstitial  fluids,  which 
state  is  maintained  by  the  agents  of  the  circu- 
lation and  secretion,  namely,  the  bloodvessels 
and  lymphatics.  Any  thing  which  interferes 
with  this  proportion,  either  the  excess  of  fluids, 
as  in  anasarca  or  phlegmonous  erysipelas,  or 
the  diminution  of  the  humours,  as  in  old  age 
and  in  many  diseases,  will  impair  or  destroy  the 
phenomena  observable  in  the  sound  state  of  the 
cellular  membrane,  and  will  explain  in  the 
former  case,  Ihe  pitting  which  is  seen  on  making 
pressure  on  the  skin;  and  in  the  latter,  that 
flabbiness  and  wrinkling  of  the  integument 
about  the  face  and  other  parts  of  the  body,  so 
characteristic  of  those  advanced  in  life  or  re- 
duced by  disease.  We  can  in  this  manner 
understand  how  a  class  of  phenomena  may  be 
dependent  on  a  physical  property,  and  yet 
be  modified  by  the  condition  of  the  vital  powers, 
so  as  to  become  impaired  by  disease,  and 
destroyed  by  death. 

The  exhalation  and  absorption  of  which  the 
cellular  substance  is  the  seat,  have  been  sup- 
posed by  many  high  authorities  to  be  effected 
by  its  elastic  contractility ;  but  it  is  probable 
that  these  phenomena,  although  in  part  de- 
pendent on  that  property,  are  principally  pro- 
duced by  the  power  of  imbibition,  which,  ac- 
cording to  the  experiments  of  MM.  Magendie 
and  Fod6ra,  exists  in  all  the  soft  parts  of  the 
body. 

Functions. — The   offices    accomplished   by 

*  Elem.  of  Physics,  Introd.  p.  xxvi. 


this  substance  in  the  economy  seem  to  be,  first, 
that  of  uniting  together  the  various  constituent 
parts  of  the  body,  and  of  keeping  them  in  situ 
by  its  contractile  force ;  secondly,  of  facilitating 
their  movements  by  means  of  its  lubricating 
fluid,  and  thus  preventing  the  injurious  effects 
of  friction  and  concussion ;  and  lastly,  of  fur- 
nishing an  appropriate  structure  for  their  recep- 
tion. It  has  also  been  supposed  that,  being  a 
bad  conductor  of  caloric,  it  will  tend  to  pre- 
serve the  uniform  temperature  of  the  body. 

Development. — The  first  trace  of  an  organized 
substance  observed  in  the  embryo  consists  of  a 
very  soft  and  pulpy  cellular  tissue,  which  at 
this  early  period  is  loaded  with  fluid;  and 
being  homogeneous  in  its  nature,  it  presents 
neither  fibres  nor  interstices,  although  it  may 
be  readily  permeated  by  air  or  liquids,  so  as  to 
produce  small  cells,  and  may  likewise  be  drawn 
out  into  glutinous  filaments.  In  proportion  as 
the  several  organs  become  developed,  it  acquires 
greater  consistency,  and  is  at  the  same  time 
diminished  in  quantity.  At  the  period  of  birth 
it  is  still,  however,  in  a  very  soft  and  imperfect 
state,  and  only  acquires  its  proper  density  by 
slow  degrees ;  in  old  age,  being  deprived  of  a 
large  portion  of  its  fluid,  and  perhaps  otherwise 
deteriorated,  it  loses  much  of  its  elastic  force ; 
and  this  circumstance,  joined  to  its  diminished 
bulk,  is  a  principal  cause  of  that  loss  of  rotun- 
dity so  conspicuous  in  the  bodies  of  aged 
persons,  and  of  the  flabbiness  of  the  several 
organs. 

The  power  of  reproduction  is  greater  in  this 
than  in  any  other  tissue,  so  that  it  is  not  only 
readily  formed  again  within  certain  limits  when 
it  has  been  destroyed,  but  it  even  appears  to 
supply  the  place  of  other  and  dissimilar  struc- 
tures which  may  have  been  lost  by  disease. 

The  cellular  substance  presents  but  few  mo- 
difications of  importance  when  examined  in 
the  different  classes  of  animals,  except,  indeed, 
that  it  is  generally  believed  to  constitute  the 
entire  body  in  those  species  that  are  placed  at 
the  bottom  of  the  scale.  The  Porifera  afford  an 
example  of  the  simplest  form  of  the  cellular  tex- 
ture with  which  we  are  at  present  acquainted  ; 
the  body  of  these  animals  consists  of  a  soft 
gelatinous  substance  composed  of  translucent 
globules,  which,  however,  are  not  perceptibly 
joined  together ;  so  that  there  is  in  this  instance 
nothing  of  that  fibrous  structure,  which  is  the 
great  characteristic  of  the  cellular  membrane  in 
the  human  body  and  in  the  higher  orders  of  ani- 
mals. In  the  semifluid  and  jelly-like  body  of  the 
Polypifera  and  of  some  of  the  Acalephae,  there 
is  merely  a  pulpy  substance,  which,  although  it 
may  exhibit  a  distinct  digestive  cavity,  and  even 
tubes  communicating  with  this,  yet  no  mus- 
cular tissue  has  hitherto  been  discovered.  In 
these  animals,  however,  rapid  movements  are 
seen  in  the  cilia;  and  the  tentacula,  when  pre- 
sent, together  with  the  entire  body,  are  capable 
of  spontaneous  motion ;  it  is  evident,  then,  in 
these  and  other  instances,  that  if,  as  is  gene- 
rally supposed,  there  be  an  absence  of  muscles, 
the  cellular  tissue  must  be  endowed  with  a  pro- 
perty totally  wanting  in  that  substance  as  it 
exists  in  the  higher  animals.  When  it  is  con- 


CELLULAR  TISSUE. 


513 


sidered  how  little  is  known  respecting  the  real 
structure  of  the  Infusoria,  Zoophytes,  &c.,  and 
when  the  numerous  discoveries  which  have  of 
late  years  been  made  in  these  and  much  higher 
animals,  of  parts  whose  existence  was  formerly 
doubted  or  denied,  are  recollected,  we  shall  be 
inclined  to  think  that  there  are  special  organs  of 
motion  provided  ;  for  it  would  be  in  direct  oppo- 
sition to  the  simple  but  constant  laws  observed 
in  the  animal  creation,  were  the  organic  tis- 
sue, entitled  the  cellular,  to  acquire  in  the  lower 
classes  a  power  of  contraction,  which  in  the 
higher  it  does  not  possess,  and  which  property 
is  the  endowment  of  a  totally  distinct  system  of 
organs,  namely,  the  muscles.  Whichsoever  of 
these  opinions  be  correct,  there  is  no  doubt  that 
in  the  least  perfect  animals,  a  soft  and  gelatinous 
matter,  analogous  to  the  cellular  tissue,  and 
loaded  with  fluids,  greatly  predominates.  As 
we  advance  in  the  scale,  it  is  found  that  organ- 
ized substances  of  a  diversified  character  are 
developed  in  the  nidus  afforded  by  this  cellular 
texture,  the  proportion  of  which  to  the  other 
structures  becomes  thus  diminished. 

MORBID  CONDITIONS  OF  THE  CELLULAR 
TISSUE. — As  the  cellular  membrane  is  so  in- 
timately united  with  all  other  organs,  it  is  very 
liable  to  be  involved  in  diseases  commencing 
in  these  parts;  but  morbid  action  also  very 
frequently  arises  primarily  in  this  tissue.  It 
is  subject  to — 1,  inflammation,  acute  and  chro- 
nic, circumscribed  and  diffused;  to  the  effects 
of  inflammation,  thickening  and  induration, 
suppuration,  ulceration,  and  mortification;  2,  in- 
filtration of  blood,  serum,  air,  and  occasionally 
of  other  substances,  as  urine;  3,  induration, 
occurring  in  new-born  infants  ;  4,  morbid 
growths,  such  as  fibrous  productions,  cysts, 
melanosis,scirrhus,  vascular  sarcoma;  5,  foreign 
bodies ;  6,  preternatural  increase  or  hypertro- 
phy, and  degeneration,  or  atrophy. 

I.  INFLAMMATION. — This  tissue  is  very  fre- 
quently affected  by  inflammation,  which  may 
either  present  itself  under  the  form  of  a  distinct 
affection,  as  when  it  attacks  the  subcutaneous 
cellular  membrane  especially,  or  it  may^  occur 
as  a  part  of  some  other  disease,  as  when  inflam- 
mation of  the  parenchyma  of  the  lungs,  liver, 
&c.,  spreads  to  the  cellular  tissue  in  which  this 
substance  is  universally  involved. 

a.  Acute  circumscribed inflatnmation,or phleg- 
mon.— The  anatomical  characters  of  this  form 
of  inflammation  of  the  cellular  substance  are 
essentially  the  same  in  whatever  part  of  the 
body  it  may  arise,  either  in  the  subcutaneous 
tissue,  or  in  that  part  which  penetrates  into  the 
interior  of  the  various  organs ;  it  will,  therefore, 
be  proper  to  trace  the  effects  of  it  in  a  general 
manner. 

1.  Congestion  of  the  bloodvessels. — The  ef- 
fects of  irritation  on  the  capillary  vessels,  in 
which  the  phenomena  of  inflammation  are  prin- 
cipally observed,  may  be  beautifully  seen  with 
the  aid  of  a  sufficiently  powerful  microscope  in 
the  transparent  membrane  of  the  frog's  foot. 
After  having  familiarized  the  eye  by  watch- 
ing the  circulation  for  a  short  time,  we  shall 
find  that  the  first  effect  produced  by  the  appli- 
cation of  an  irritant  is  a  distinct  and  evident 


acceleration  of  the  blood's  motion.  I  have  not 
been  able  to  satisfy  myself  of  that  diminution 
of  the  calibre  of  the  vessels  which  is  said  by 
some  observers  to  accompany  this  acceleration. 
If  the  irritation  be  repeated,  or  if  its  power  in 
the  first  instance  were  considerable,  it  will  be 
seen  after  a  certain  time  that  the  capillary  ves- 
sels become  dilated,  that  the  blood  moves  more 
slowly,  and  often  that  it  oscillates  and  circulates 
apparently  with  difficulty  ;  its  constituent  parts 
become  less  distinct,  the  particles  being  crowded 
together.  If  the  effects  of  the  irritation  now 
subside,  the  dilated  vessels  contract  and  recover 
their  proper  calibre,  the  blood  again  moves 
more  freely,  and  the  circulation  regains  its 
natural  state ;  but,  on  the  contrary,  if  the  mor- 
bid action  still  persists,  the  membrane  begins 
to  grow  opaque,  either  in  consequence  of  the 
engorgement  of  the  vessels,  or,  as  it  has  appeared 
to  me,  from  an  extravasation  of  one  or  other  of 
the  constituents  of  the  blood;  or,  lastly,  the 
circulation  altogether  ceases,  the  vessels  are 
further  enlarged,  the  blood  is  stagnant,  and  is 
evidently  deteriorated  in  quality,  and  the  colour 
becoming  deeper  and  deeper,  is  at  length  per- 
fectly brown,  or  even  black.  This  is  the  order 
in  which  the  phenomena  in  the  derangement  of 
the  circulation  occur ;  and  although  they  have 
been  more  particularly  studied  in  microscopical 
observations  on  the  lower  animals,  yet  many  of 
them  are  daily  to  be  observed  in  the  human 
body  during  the  progress  of  inflammation. 
Whilst  the  inflammatory  action  is  confined  to 
the  first  of  the  above  stages,  in  which  there  is 
merely  a  preternatural  excitement  of  the  circu- 
lation, it  may  be  arrested  and  put  an  end  to 
without  any  further  morbid  change;  and  this 
may  even  happen  in  the  second  stage,  where 
the  blood,  although  accumulated  and  retarded 
in  its  motion,  still  circulates  in  its  proper  ves- 
sels. This  speedy  termination  of  the  disease 
has  been  called  by  the  French  writers  deli- 
tescence. 

2.  Effusion. — When  the  bloodvessels  are 
greatly  congested  and  dilated,  it  usually  hap- 
pens that  a  part  of  their  contents  escapes,  and  the 
cellular  tissue  becomes  loaded  with  coagulable 
lymph,  more  or  less  tinged  with  blood  accord- 
ing to  the  vascularity  of  the  affected  part,  pro- 
ducing that  condition  which  has  been  called 
red  induration.  This  substance,  by  agglutina- 
ting together  the  fibres  and  layers,  causes  the 
hardness  which  is  so  perceptible  on  pressing 
the  diseased  part.  At  the  same  time  that  this 
solid  deposition  takes  place  in  the  centre,  it  is 
found  that  the  circumference  of  the  inflamed 
part  is  soft  and  redematous,  in  consequence  of 
the  cells  being  distended  with  a  fluid  which 
appears  to  be  the  serum  of  the  blood.  Although 
the  cellular  tissue  is  rendered  more  firm  to  the 
touch  by  the  effusion  of  lymph,  yet,  as  happens 
in  the  other  organized  structures  of  the  body 
when  attacked  by  acute  inflammation,  the  co- 
hesion of  its  fibres  is  diminished,  and  it  is,  con- 
sequently, more  easily  torn  than  in  its  natural 
state,  and  its  elasticity  is  also  greatly  impaired. 
The  preceding  changes  may  be  very  beautifully 
observed  in  the  progress  of  pneumonia,  when 
the  substance  of  the  lungs  is  passing  into  that 


514 


CELLULAR  TISSUE. 


condition  which  is  called  red  hepatization.  I 
have  in  my  possession  a  specimen  of  com- 
mencing hepatization,  taken  from  a  lung  in 
another  portion  of  which  that  change  was  quite 
complete.  In  this  preparation  a  portion  of  the 
pulmonary  tissue  is  of  a  reddish  brown  colour, 
and  evidently  infiltrated  with  a  solid  substance, 
consisting,  it  may  be  presumed,  of  fibrine 
mixed  with  the  colouring  matter  of  the  blood. 
The  manner  in  which  this  deposition  took  place 
in  the  cellular  tissue  of  the  organ  is  distinctly 
seen,  the  reddish  colour  being  gradually  shaded 
off  till  it  is  lost  in  the  healthy  structure. 

It  sometimes  happens  that  the  morbid  action 
now  ceases,  and  that  by  a  process  of  absorption 
the  interstitial  effused  matter  is  removed,  so  as 
slowly  to  restore  the  part  to  its  proper  condition : 
this  is  the  termination  of  inflammation  to  which 
the  term  resolution  is  applied. 

3.  Suppuration. — lUisually  happens  in  acute 
inflammation  of  the  cellular  tissue,  that  after 
the  lapse  of  a  certain  period,  a  softening  takes 
place  towards  the  centre  of  the  circumscribed 
hardness,  in  consequence  of  the  diminution  of 
cohesion  above  described  gradually  increasing, 
and  of  the  deposition  of  purulent  matter.     It  is 
uot  certain  how  the  pus  is  formed  in  the  first  in- 
stance; several  modern  pathologists,  especially 
in  France,  imagine  that  the  lymph  and  serum 
which   were   previously  effused   experience  a 
change  by  which  they  are  converted  into  pus, 
a  theory  which  is  rendered  probable  by  the 
physical  properties  of  pus  so  nearly  resembling 
those  of  the  blood  :  according  to  other  autho- 
rities, pus  is  a  proper  secretion  derived  from 
the  neighbouring  arteries.     I  believe  that  in  the 
beginning   the    purulent    matter  results   from 
changes  in  the  effused  matters ;  but  that  when 
suppuration  is    fully   established,  the   pus  is 
poured  out  or  secreted  from  the  bloodvessels. 
In  the  commencement  the  pus  is  observed  in 
the  cells  of  the  tissue,  under  the  form  of  whitish 
spots;  subsequently  the  walls  of  these  inter- 
stices are  broken  down  by  the  softening  alluded 
to,  and  the  purulent  matter  is  collected  together 
so  as  to   constitute  an  abscess,  which  is  sur- 
rounded  by  a  rather  dense  layer  of  cellular 
tissue,  still  retaining  the  characters  of  inflam- 
mation.   This  layer  constitutes  the  sac  of  the 
abscess,  and  presents  at  first  a  rough  and  reddish 
surface;   but  it  soon  happens  that  the  walls 
acquire  a  greater  firmness,  and  that  the  surface 
of  the  sac  assumes  very  much  the  appearance 
of  a  mucous  membrane. 

4.  Ulceration. — When  an  abscess  has  thus 
been  formed,  the  cellular  tissue  intervening  be- 
tween it  and  the  external  surface  of  the  body,  is 
removed  by  the  action  of  the  absorbents.     This 
process,  which  is  always  preceded  by  inflam- 
mation, and  accompanied  by  suppuration,  is 
distinguished  from  various  other  morbid  actions 
of  the  absorbents  by  the  term  of  ulceration. 
Other  instances  of  ulceration  occurring  in  the 
cellular    tissue    might    be    adduced ;    ex.  gr. 
the  separation  of  the  slough  in  carbuncle,  after 
extravasation  of  urine,  &c. 

5.  Mortification. — If  the  inflammatory  action 
be  sufficiently  intense,  it  causes  the  destruction 
of  the  vitality  of  the  part  affected,  and  pro- 


bably in  the  manner  suggested  by  Professor 
Andral.  "In  the  most  acute  form  of  hyper- 
aemia,*  the  circulation  of  the  blood  is  sus- 
pended, and  if  this  stagnation  be  prolonged  so 
as  to  become  complete,  the  parts  being  gorged 
with  blood  that  is  no  longer  renewed,  and 
which,  therefore,  soon  becomes  unfitted  to  sup- 
port nutrition  and  life,  must  necessarily  perish, 
and  in  this  manner  gangrene  is  produced,  as  in 
the  experiments  performed  by  Dr.  Hastings. 
In  these  cases  the  black  colour  announces  the 
stagnation  of  the  blood,  and  this  stagnation 
being  prolonged,  must  of  necessity  lead  to 
gangrene.  Such,  in  my  opinion,  is  the  manner 
in  which  the  species  of  gangrene  usually  attri- 
buted to  excess  of  inflammation,  is  produced." 
M.  Gendrin  has  ascertained  by  dissection  that 
some  of  the  vessels  are  filled  with  coagulated 
blood ;  whilst  others  are  actually  ruptured,  and 
allow  their  contents  to  escape.  The  cessation 
of  the  circulation  has  for  a  long  time  been 
remarked  as  the  most  striking  character  of  mor- 
tification; in  fact,  that  cessation,  in  whatever 
manner  it  may  have  been  induced,  whether  by 
inflammation,  by  continued  pressure,  by  the 
application  of  tight  bandages  to  a  limb,  &c.,  is 
in  the  great  majority  of  instances  the  imme- 
diate cause  of  mortification.  The  consequence 
of  this  loss  of  vital  action  is,  that  the  natural 
properties  and  appearance  of  the  cellular  tissue 
are  destroyed ;  the  affected  part  becomes  dis- 
coloured, usually  assuming  a  black  or  ash- 
coloured  appearance;  the  proper  texture  is 
lost,  and  the  part  is  infiltrated  with  a  dark 
sanious  fluid,  and  is  subsequently  converted 
into  a  shapeless  mass  of  pulpy  substance,  which 
is  cold  to  the  touch,  and  extremely  offensive 
to  the  smell,  owing  to  the  gases  which  are 
generated  by  putrefaction :  in  fact,  the  part  is 
dead,  and  presents  the  usual  appearances  caused 
by  the  decomposition  of  animal  matter,  con- 
joined with  those  which  result  from  the  pre- 
vious effects  produced  in  the  circulation  by  the 
inflammatory  action,  especially  the  engorge- 
ment of  the  bloodvessels.  These  are  the  changes 
induced  in  the  cellular  substance  when  it  is 
attacked  by  humid,  or,  as  it  has  been  called, 
inflammatory  gangrene.  In  dry  gangrene,  on 
the  contrary,  the  black  and  discoloured  part 
shrivels  up,  and  does  not  undergo  the  same 
changes  which  are  produced  by  the  decompo- 
sition of  a  texture  which  is  loaded  with  fluids. 

b.  Chronic  inflammation. — As  we  find  that 
in  phlegmon  there  is  a  great  tendency  to  the 
formation  of  pus,  so  in  chronic  inflammation 
there  is  usually  a  deposition  of  solid  matter, 
which  produces  more  or  less  of  induration  and 
enlargement.  This  deposition  seems  almost  in 
every  instance  to  occur  in  the  cellular  tissue, 
either  where  it  is  interstitial,  or  where  it  pene- 
trates into  the  interior  of  the  several  organs. 
This  is  observed  among  other  parts  in  chronic 

*  This  is  a  general  term  employed  by  M .  Andral 
to  designate  the  increased  quantity  of  blood  which 
is  contained  in  the  capillary  vessels  of  any  organ, 
without  any  reference  to  the  cause  which  produces 
the  accumulation.  In  the  passage  above  quoted, 
he  is  speaking  of  acute  hyperaemia,  which  is  syno- 
nymous with  acute  inflammation. 


CELLULAR  TISSUE. 


615 


inflammation  of  glands,  as  the  testis,  mamma, 
liver,  tonsil,  &c. ;  in  the  lymphatic  glands, 
especially  in  scrofulous  persons  ;  in  various  dis- 
eases of  the  joints ;  in  the  hard  swellings  so  often 
seen  in  scrofula,  gout,  and  rheumatism ;  in 
imperfectly  cured  erysipelas,  pellagra,  and  ele- 
phantiasis ;  in  the  callous  edges  of  old  ulcers ; 
in  the  uterus,  labia  pudendi,  and  prepuce  of 
the  penis  ;  and,  according  to  Otto,*  in  that  pe- 
culiar induration  of  the  cellular  tissue  which 
occurs  in  new-born  children.  This  distin- 
guished pathologist,  in  common  with  many 
other  continental  writers,  attributes  phlegma- 
sia  dolens  to  the  same  cause.  The  incorrect- 
ness of  this  opinion  has  been  demonstrated  by 
the  researches  of  Dance,  Arnott,  Lee,and  others. 
(See  VEIN.) 

The  great  induration  often  induced  by  long- 
continued  chronic  inflammation  was  called  by 
the  older  writers  scirrhus ;  and  even  in  the 
present  day  most  of  the  French  pathologists 
apply  that  term  to  the  hardness  thus  induced, 
as  well  as  to  the  malignant  disease,  to  indicate 
which  English  practitioners  restrict  the  word. 

The  substances  that  are  effused  into  the  cel- 
lular tissue  in  chronic  inflammation  are  various, 
according  to  the  part  attacked,  the  circum- 
stances of  the  disease,  constitution,  &c.  It 
generally  consists  of  a  whitish  or  greyish  matter, 
of  a  lardaceous,  homogeneous  appearance,  caus- 
ing what  is  called  by  modern  pathologists,  white 
induration  ;  and  sometimes  it  is  of  a  yellowish,  or 
even  bluish  colour.  It  is  doubtful  whether  this 
substance  consists  of  the  fibrine  or  albumen  of 
the  blood,  or  of  some  newly  formed  material.  In 
scrofulous  individuals  the  deposition  consists  of 
the  well-known  caseous  matter,  so  characteristic 
of  the  strumous  diathesis;  lastly,  this  form  of 
inflammation,  especially  in  strumous  constitu- 
tions, often  leads  to  the  formation  of  chronic 
abscess,  the  contents  of  which,  as  Gendrin, 
Mayo,  and  others  have  observed,  do  not,  how- 
ever, consist  of  true  pus,  but  of  serum  generally 
mixed  with  a  flakey  matter,  or  even  tinged  with 
blood. 

c.  Spreading  or  diffuse  inflammation. — The 
cellular  tissue,  constituting  in  all  parts  of  the 
body  an  uninterrupted  secreting  surface,  is  sub- 
ject to  spreading  inflammation,  which,  from  the 
extent  of  the  parts  implicated,  the  disorganiza- 
tion induced,  and  the  alarming  character  of  the 
attendant  constitutional  disturbance,  must  be 
regarded  as  one  of  the  most  formidable  diseases 
to  which  the  human  body  is  subject.  In  what- 
ever manner  this  disease  originates,  whether 
from  poisoned  wounds,  from  phlegmonous  ery- 
sipelas, from  external  injury,  or  from  any  other 
cause,  it  progressively  and  rapidly  attacks  a 
large  extent  of  the  cellular  tissue,  often  invading 
an  entire  limb,  or  even  a  considerable  part  of 
the  trunk.  In  examining  parts  thus  affected 
after  death,  they  are  found  to  be  variously 
altered,  according  to  the  duration  of  the  dis- 
ease and  the  order  in  which  they  became  in- 
volved ;  in  those  which  are  most  recently  im- 
plicated, the  cellular  substance  is  merely  rede- 

*  Compcnd.  of  Pathol.  Anat.  by  South,  vol.  i. 
P.  91. 


matous,  containing  a  large  quantity  of  limpid 
or  reddish-coloured  serum,  which  readily  flows 
out  on  making  an  incision,  and  which  after- 
wards acquires  more  consistence,  and  becomes 
more  deeply  coloured.  In  the  subsequent 
stages,  pus,  sometimes  pure,  sometimes  dis- 
coloured, is  effused  :  the  matter  is  at  first  con- 
tained in  the  cells,  which  are  gorged  with  a 
whitish  semifluid  matter,  but  afterwards  depots 
of  matter  take  place  in  the  disorganized  tissue ; 
there  being,  however,  no  proper  cyst,  owing  to 
the  want  of  that  barrier  of  lymph  which  is 
effused  in  common  phlegmon.  These  abscesses 
are  often  numerous,  but  insulated  and  distinct 
from  each  other  :  at  other  times  they  occupy  a 
great  extent,  and  contain  a  large  quantity  of  pus, 
often  mixed  with  shreds  of  mortified  membrane. 
In  the  more  severe  forms  of  this  affection  the 
natural  organization  is  in  some  places  totally 
destroyed,  and  the  cellular  substance,  from  the 
effects  of  gangrene,  is  converted  into  a  greyish 
or  dark-coloured  slough. 

These  changes  are  not  confined  to  the  sub- 
cutaneous membrane,  in  which,  however,  they 
are  principally  observed,  but  are  seen  in  the 
cellular  sheaths  of  the  muscles,  and  even  in  the 
processes  which  separate  their  different  fasciculi. 
The  muscles  themselves,  under  these  circum- 
stances, partake  in  the  disorganization,  and  lose 
their  proper  colour. 

The  progress  of  this  formidable  disease  would 
seem  to  shew  that  an  acrid  and  irritating  hu- 
mour is  effused  into  the  cellular  substance, 
where  it  rapidly  causes  suppuration  and  slough- 
ing, in  the  same  manner  as  when  urine  is  ex- 
tra vasated  into  the  perinseum  and  scrotum. 
That  a  vitiated  state  of  the  blood  is  often  pro- 
duced is  a  now  well-known  fact,  and  such  a 
condition  appears  to  be  induced  in  the  disease 
under  consideration,  either  in  consequence  of 
the  introduction  of  a  poison  into  the  system,  as 
from  the  bite  of  a  venomous  serpent,  or  from  a 
deterioration  of  the  constitution,  as  in  draymen, 
coal-porters,  and  others,  who  in  large  towns  con- 
sume enormous  quantities  of  fermented  liquors; 
or,  lastly,  from  both  these  causes  combined,  as 
from  punctures  received  in  dissection  by  indi- 
viduals who  at  the  time  are  in  an  indifferent 
state  of  health. 

II.  INFILTRATION,  or  effusion. — The  escape 
of  various  fluids  from  their  proper  receptacles 
into  the  cellular  tissue  is  of  extremely  frequent 
occurrence. 

a.  Blood. — This  is  effused  either  as  a  conse- 
quence of  external  violence  acting  on  the  arte- 
ries and  veins,  or  from  an  internal  cause,  of 
which  the  nature  is  more  obscure.     When  the 
hemorrhage  is  extensive,  the  surrounding  tissue 
is  unable  to  resist  the  progress  of  the  blood, 
and  the  infiltration  becomes  of  considerable  ex- 
tent.    It  is  by  effusions  of  this  kind  that  ecchy- 
moses, false  aneurisms,  &c.  are  formed. 

b.  Serum. — A  very  common  morbid  change 
is  the  infiltration  of  a  thin  watery  fluid  into 
this  tissue,  consisting  of  an  accumulation   of 
the  serum  naturally  exhaled  into  its  cells.    The 
effused  fluid,  apparently  owing  to  its  contain- 
ing a  larger  proportion  of  albumen  than  usual, 
is  occasionally  of  a  more  viscid  nature,  so  as 


516 


CELLULAR  TISSUE. 


to  escape  but  imperfectly  on  a  puncture  being 
made ;  and  in  other  cases,  as  in  the  diffused 
swelling  so  often  occurring  in  bad  constitutions 
after  serious  local  injury,  compound  fractures, 
poisoned  wounds,  &c.  the  effused  fluid  is  of 
an  acrid  character.  The  effusion  is  often 
restricted  to  a  particular  region,  (oedema ;) 
at  other  times  it  is  more  extensive,  and 
may  even  occur  in  all  parts  of  the  body 
(anasarca).  In  all  instances  in  which  effusion 
takes  place,  it  ought  to  be  regarded  simply  as 
an  effect,  resulting  from  some  previous  change 
in  the  vessels  of  the  cellular  tissue,  which 
stands  in  the  relation  of  a  cause.  This  change 
consists,  I  believe,  in  the  great  majority  of 
cases,  if  not  in  all,  in  a  preternatural  con- 
gestion of  the  bloodvessels,  which  may  be 
induced  by  inflammation,  debility,  mechanical 
obstruction  to  the  free  return  of  the  venous 
blood,  or  the  suspension  of  any  of  the  great 
secretions  of  the  body. 

c.  Air. — Emphysema,    in    its   usual    form, 
arises  from  an  unnatural  communication  being 
formed  between  some  part  of  the  air-passages 
and  the  cellular  tissue  (traumatic  emphysema)  : 
it  is  thus  an  occasional  consequence  of  fracture 
of  the  ribs,  in  which  the  neighbouring  portion 
of  the  lung  is  lacerated  ;  of  penetrating  wounds 
of  the  chest;    of  rupture  of  the  air-cells  by 
violent  exertions ;    of  ulceration    of    the  air- 
cells  ;  of  rupture  of  the  membrane  of  the  larynx, 
and  even  of  the  lachrymal  sac  and  windpipe, 
and  of  fractures  in  the  vicinity  of  the  frontal 
sinuses,  causing  a  laceration  of  their  mucous 
membrane.      Emphysema  has  been  likewise 
known  to  arise  spontaneously,  the  air  appear- 
ing to  be  secreted  from  the  bloodvessels  ;  and 
it  is  also  a  frequent  attendant  on  gangrene,  in 
which  case  the  effused  air  is  the  result  of  the 
decomposition  of  the  fluids  previously  col- 
lected. 

d.  Urine. — Effusion  of  urine  may  arise  from 
a  wound  or  ulceration  of  any  of  the  organs 
through  which  the  urine  passes ;  usually,  how- 
ever, it  is  a  consequence  of  an  injury  of  the 
bladder  or  urethra.     The  accident  particularly 
demands  notice  on  account  of  the  destructive 
effects  which  result  from  it.     These  effects  are 
extensive  mortification  of  the  cellular  tissue, 
and,  in  a  somewhat  less  degree,  of  the   skin, 
followed  by  profuse  suppuration,  attended  with 
constitutional  symptoms  of  so  serious  a  nature 
as  often  to  cause  the  death  of  the  patient. 

III.  INDURATION. — Induration  occurs  as  a 
special  disease  in  new-born  infants,  and  in  a 
large  proportion  of  those  who  are  attacked, 
there  is  a  fatal  termination  from  the  sixth 
to  the  thirtieth  day ;  in  very  severe  cases, 
and  in  infants  prematurely  born,  death  may 
take  place  in  two,  three,  or  four  days.  Some 
idea  of  the  mortality  in  this  disease  may  be 
formed  from  the  following  facts :  in  the 
Foundling  Hospital  in  Paris,  the  mortality  of 
late  years  has  been  one  in  three  ;  out  of  twenty- 
seven  cases  occurring  in  1809,  at  La  Charite" 
in  Berlin,  only  two  were  saved;  in  fifteen 
cases  seen  by  Lobstein,  four  recovered. 

The  disease  is  very  prevalent  in  the  large 
foundling  hospitals  on  the  continent,  as  many 


as  240  cases  occurring  in  one  year  in  the  Hos- 
pice des  Enfans  Trouv6s  of  Paris,  out  of 
5392  received  into  the  institution.  In  this 
country,  where,  fortunately  for  humanity,  no 
such  establishments  exist,  and  where  conse- 
quently new-born  infants  are  but  rarely  deserted 
by  the  mother,  the  disease  is  very  rare.  Dr. 
Copland  states  that  he  has  not  met  with  an 
instance  of  it  in  the  Queen's  Lying-in  Hospital, 
and  that  even  in  the  Infirmary  for  Children, 
such  cases  are  very  rarely  presented.  I  have 
made  inquiries  of  several  very  extensive  prac- 
titioners of  midwifery,  some  of  whom  are  con- 
nected with  public  institutions,  and  they  have 
very  rarely  or  never  seen  the  disease. 

The  parts  which  are  attacked,  usually  the 
legs,  hands,  and  face,  are  more  or  less  swollen, 
hard,  and  rigid  to  the  touch ;  and  the  skin 
assumes  a  red  or  violet  colour  in  consequence 
of  the  respiration  being  imperfectly  performed. 
The  affection  consists  of  an  cedematous  state  of 
the  cellular  tissue,  the  areolae  being  loaded 
with  a  concrete  albuminous  matter  and  a  sero- 
sanguineous  fluid,  which  oozes  out  when  a 
section  is  made  and  quickly  coagulates  ;  it  is 
this  infiltration  that  is  the  cause  of  the  peculiar 
hardness,  for  according  to  M.  Billard,  who  has 
carefully  investigated  the  characters  of  the  dis- 
ease, the  cellular  fibres  and  layers  preserve  all 
their  flexibility,  and  present  no  signs  of  having 
undergone  any  organic  change.  According  to 
M.  Chevreul,  in  this  disease  the  serum  of  the 
blood  contains  an  abundant  quantity  of  a  matter 
distinct  from  fibrin,  but  which  spontaneously 
coagulates ;  this  substance  is  perfectly  identical 
with  the  material  to  which  the  cellular  tissue 
owes  its  apparent  induration. 

The  history  of  this  disease,  and  the  results 
obtained  by  dissection,  prove  that  venous  con- 
gestion is  a  very  constant  morbid  appearance ; 
and  it  is  a  question  that  has  not  hitherto  been 
decided,  how  far  this  congestion  is  the  exciting 
cause  of  the  disease. 

IV.  MORBID  GROWTHS.  —  These  are  of 
very  common  occurrence  and  of  very  various 
characters ;  some  consisting  of  the  trans- 
formation of  the  cellular  membrane  into  other 
tissues,  the  fibrous  and  osseous  for  example; 
whilst  others  are  entirely  new  productions,  and 
occasionally  prove  of  a  malignant  nature,  such 
as  cysts,  vascular  sarcoma,  scirrhus,  melanosis, 
&,c.  We  do  not  often  meet  with  bony  or 
fibrous  formations  in  the  common  cellular 
structure,  although  I  have  occasionally  seen 
growths  with  these  characters.  From  an  ex- 
amination of  many  specimens,  I  am  induced 
to  believe  that  the  ossific  deposits  not  unfre- 
quently  observed  in  connection  with  the  fibrous 
and  serous  membranes,  as  the  dura  mater, 
pleura,  &c.  are  formed  in  the  cellular  tissue  of 
these  structures. 

V. — FOREIGN  BODIES  are  sometimes  intro- 
duced into  the  cellular  tissue  from  without, 
such  as  bullets,  needles,  &c.  Certain  para- 
sitic animals,  the  origin  and  characters  of 
which  are  very  obscure,  are  also  occasionally 
met  with  in  the  substance  of  the  human  body, 
and  especially  in  the  cellular  tissue.  At  the 
present  day  it  is  generally  admitted  that  by- 


CEPHALOPODA. 


517 


datids  are  bodies  endowed  with  vitality,  the 
most  common  species  of  which  is  the  acepha- 
locyst ;  another  species  is  the  cysticercus  ccl- 
lulosus.  The  filaria  incdinensis,  or  guinea- 
worm,  is  another  parasitic  animal  which  has 
been  seen  in  the  human  body. 

Lastly,  the  cellular  tissue  may  vary  in  the 
degree  of  its  consistence,  colour,  &c. ;  and 
owing  to  some  derangement  in  the  function  of 
nutrition,  it  may  present  a  preternatural  in- 
crease or  a  wasting  of  its  substance  :  (hyper- 
trophy or  atrophy.) 

BIBLIOGRAPHY.  —  Bordeu,  Recherches  SUP  le 
tissu  muq.,  in  his  works  by  Richerand.  W.  Hunter, 
in  Med.  Obs.  and  Inq.  vol.  ii.  p.  17.  Holler, 
Elementa  Physiolog.  The  systems  of  Portal, 
Bichat,  Meckel,  Beclard,  Craigie,  and  ^Grainger, 
Blandin  Sf  Beclard,  Add.  a  1'Anat.  Gen.  de  Bichat. 
Diet,  de  Med.  art.  Cell.  Tissue.  M.  Edwards, 
Recherches  microsc.  sur  la  struct,  intime  des  tiss. 
organ,  des  anim.  Hodgkin,  Annals  of  Phil.  Aug. 


Roget,  in  Bridgwater  Treat.,  Anim.  and  Veget. 
Phys.  Grant's  Lectures,  Lancet,  1833,  34,  vol.  ii. 
p.  257.  De  Blainville,  De  1'organi?.  des  animaux. 
Hunter,  Treatise  on  the  blood,  &c.  Thomson's 
Lectures  on  inflammation.  James,  Observations 
on  inflammation.  Portal,  Cours  d'anat.  med.  t.  ii. 
t.  v.  Lawrence,  Lectures  on  inflammation,  in  Lancet, 
vol.  i.  1829,  30.  Hastings,  Treatise  on  the  lungs, 
p.  57.  Billard,  Traite  des  mal.  des  enf.  nouv.-nes, 
p.  169.  Gendrin,  Hist.  anat.  des  inflam.  t.  i.  p.  14  ; 
t.  ii.  358.  Andral,  Precis  d'anat.  pathol.  Otto,  Com- 
pendium of  pathological  anatomy,  by  South.  Cbp- 
land,  Diet,  of  Pract.  Med.  art.  Cellular  Tissue.  Wells, 
Transactions  of  a  Society  for  Improvement  of  Medi- 
cal and  Chirurgical  Knowledge,  vol.  iii.  Breschet, 
Recher.  sur  les  hydrop.  actives,  &c.  Paris,  1812. 
Blackall,  Obs.  on  dropsy,  London,  1813.  Aber- 
crombie,  in  Edin.  Med.  and  Sur.  Journal,  vol.  xiv. 
Ayre's  Researches  into  the  nature  and  treatment  of 
dropsy,  p.  1  et  seq.  Cyclop,  of  Pract.  Med.  art. 
Anasarca.  Diet,  de  Med.  et  de  Chir.  Prat.  art. 
Acephalocystes ,  Anasarque,  Emphyseme,  Entozoaires, 
Inflammation.  Mayo,  Outlines  of  human  patho- 
logy. Lobstein,  Traite  d'afnat.  pathol.  p.  201. 
Duncan,  in  Trans,  of  Med.  Chir.  Soc.  Edin.  vol.  i. 
(R.  D.  Grainger.) 


CEPHALOPODA— (xi<pa*»j,  caput, 
pes);  Eng.  Cephalopods ;  Fr.  Cephalopodes  ; 
Germ.Kopjfusslern,  Blackfische,  Tinten-fische  ; 
Ital.  Seppie,  Polpi.  Syn.  MaAaxfe,  Aristotle ; 
Mollia,  Pliny;  the  genera  Nautilus,  Argo- 
nauta,  and  Sepia,  Linne ;  Octopodia,  Schneider; 
Mollusca  brachiata,  Poli ;  Mollusca  Cephalo- 
poda, Cuvier ;  Cephalopoda,  Lamarck,  Leach ; 
Brachiocephala,  Cephalophores,  De  Blainville ; 
Pterygia,  Latreille,  (including  the  Pteropoda 
of  Cuvier);  Antliobrachionophora,  Gray. 

Definition. — A  class  of  Molluscous  Inver- 
tebrate animals  in  which  the  head  (A,  figs. 
206,  209,)  is  situated  between  the  trunk  (B) 
and  the  feet  (C),  or  principal  organs  of  loco- 
motion. 

Characters  of  the  Class. — The  trunk  or  body 
is  thick  and  soft ;  varying  in  form  from  a 
sphere,  to  a  flattened  ellipse,  or  elongated 
cylinder;  sometimes  protected  by  a  shell, 
sometimes  naked;  consisting  of  a  membranous 
or  muscular  sheath  or  mantle,  with  a  transverse 


anterior*  aperture  (rt,  figs.  206,  ct  seq.)  and 
containing  the  respiratory,  circulating,  gene- 
rative, and  principal  digestive  viscera :  the 
mantle  sometimes  supports  a  pair  of  fins  (b, 
figs.  207,  208,  209,)  and,  in  the  naked  species, 
lodges  in  its  substance  the  rudiments  of  a  shell. 

The  head  is  distinct  from  the  trunk,  of  large 
size,  and  of  a  rounded  figure  ;  it  contains  the 
organs  of  sense,  mastication,  and  deglutition,  and 
gives  off  from  its  anterior  circumference  or  exter- 
nal surface,  a  number  of  fleshy  processes  which 
encircle  and  more  or  less  conceal  the  mouth. 

These  processes,  by  some  naturalists  termed 
ihefeet,  but  which  we  prefer  to  call,  with  Poli, 
the  arms,  are  either  very  numerous,  short,  and 
hollow,  containing  each  a  long,  slender  retrac- 
tile tentacle  (figs.  205,  213)  ;  or  they  are  eight 
(figs.  206,  210),  or  ten  (figs.  207,  208), 
in  number,  solid,  supporting  on  their  internal 
surface  numerous  suckers  (antlia,  acetabula)  ; 
and  being  more  or  less  elongated  and  flexible  in 
every  direction,  they  act  as  powerful  organs  of 
adhesion,  prehension,  and  locomotion. 

The  eyes  are  a  single  pair,  of  large  size, 
varying  in  relative  perfection  of  structure  ac- 
cording to  the  locomotive  powers  of  the  spe- 
cies, and  either  pedunculated  or  sessile. 

The  mouth  is  anterior,  and  situated  at  the 
bottom  of  the  conical  cavity  formed  by  the 
base  of  the  feet ;  it  is  provided  with  two  horny 
or  calcareous  jaws,  shaped  like  the  mandibles 
of  a  Parrot,  playing  vertically  on  each  other, 
and  inclosing  a  large  fleshy  tongue,  which  is 
armed  with  recurved  horny,  spines. 

The  bronchia  are  concealed  within  the  man- 
tle, and  are  symmetrical  in  size,  form,  and  posi- 
tion. The  systemic  circulation  is  aided  by  a 
muscular  ventricle. 

The  infundibulum,  (i,figs.  206,  208,)  or  pas» 
sage  through  which  the  respiratory  currents  and 
the  excrements  are  discharged,  is  a  muscular 
tube,  situated  at  the  anterior  part  of  the  neck, 
shaped  like  an  inverted  funnel,  with  the  pipe 
projecting  from  the  visceral  cavity,  and  directed 
forwards. 

The  sexual  organs  are  separate  and  exist  in 
distinct  individuals ;  but  whether  impregnation 
takes  place  by  copulation  or  after  the  ova  are 
excluded  is  not  determined ;  the  former  is  most 
probable. 

All  the  species  are  aquatic  and  marine. 

Division  of  the  Class  into  Orders. —  The 
type  of  organization  which  characterizes  the 
Cephalopods,  and  of  which  the  preceding  is  a 
general  outline,  presents  two  principal  modi- 
fications, according  to  which  the  class  is  di- 
vided into  two  orders.f 

*  Throughout  the  present  article  the  terms  of 
aspect  and  position  relate  to  that  in  which  the 
animal  is  represented  in/0.206.  The  shell  covers 
the  posterior  part  of  the  body,  the  arms  are  anterior 
and  directed  forwards;  the  letters  A,  B,  C,  are 
along  the  dorsal  or  upper  surface,  the  letter  i  is 
beneath  the  ventral  or  lower  surface. 

t  A  third  order  of  Cephalopods  (the  Cellulacea 
of  De  Blainville)  has  been  proposed  to  include  an 
extensive  series  of  minute  polythalamous  shells,  of 
exquisite  beauty  in  their  form  and  sculpture,  which 
differ  from  the  camerated  shells  of  our  Tetrabran- 
chiate  order  in  the  absence  of  a  siphon,  but  which 


518 


CEPHALOPODA. 


In  the  first  of  these,  which  is  most 
closely  allied  to  the  Gasteropodous  Mol- 
lusks,  the  branchiae  are  four  in  number, 
and  the  order  is  therefore  termed  Tetra- 
branchinta  :  in  the  higher  division,  which 
approaches  nearest  to  the  Vertebrate  ani- 
mals, the  branchiae  are  two  in  number, 
and  the  order  is  called  Dibranchiata. 

Order  I.    TETRABRANCHIATA. 
Syn.   Polythalamaces,  Blainville ;    Sipho- 
nifera,  D'Orbigny;  minus  the  Spirulidtc 
and  Belemnitida. 

The    Tetrabranchiate    Cephalopods,  of 
which  the    Pearly   Nautilus    (Jig.   205) 
may  be  regarded 
as   the  type,  are 
provided   with   a 
large  external  uni- 
valve shell,  sym- 
metrical in  form 
like  the  body  of 
the  animal  which 
it     protects, 
straight,  or  con-  * 
voluted  on  a  ver- 
tical  plane,    and 
divided  by  a  se- 
ries of  partitions 
(o,  a)  into  nume- 
rous      chambers 
(6, 6),  of  which  the 
last-formed  (6')  is 

the  largest,  and  alone  contains  the  body  of  the 
animal :  a  dilatable  and  contractile  tube  (c,  c) 
is  continued  from  the  posterior  part  of  the 

M.  D'Orbigny  believes  to  be  constructed  by  mol- 
luscous animals  of  a  grade  of  organization  which 
entitles  them  to  rank  with  the  Cephalopodous  class. 
For  this  group  of  animals  M.  De  Haan  has  pro- 
posed the  name  of  Asiphonoidea  ;  but  M.  D'Orbigny, 
observing  that  the  chambers  of  their  shells  com- 
municate together  by  means  of  one  or  more  fora- 
mina, has  substituted  the  positive  term  Foraminifera, 
and  they  are  placed  by  Cuvier  at  the  end  of  the 
Cephalopodous  class  under  that  denomination  in 
the  last  edition  of  the  Regne  Animal. 

Strong  evidence  has,  however,  been  recently  ad- 
duced to  prove  that  these  minute  shells  owe  their 
existence  to  animals  which  have  no  pretensions  to 
rank  with  the  Cephalopods  ;  but  before  we  give  the 
account  of  M.  Dujardin,  who  is  the  author  of  this 
view,  we  shall  first  quote  M.  D'Orbigny's  own 
description  of  the  animal  of  the  shells,  the  struc- 
ture of  which  he  has  so  ably  studied  and  so  happily 
demonstrated  by  means  of  enlarged  models. 

"  The  Cophalopods  of  the  Foraminiferous  Order 
have  a  bursiform  body,  in  the  posterior  part  of 
which  the  shell  is  lodged  ;  the  body  of  the  animal 
sometimes  presents  a  great  size  compared  to  that 
of  the  head,  to  which  it  is  occasionally  subservient 
as  a  means  of  protection,  entirely  surrounding  it 
in  the  anterior  folds  of  the  skin.  The  head  is 
small,  scarcely,  if  at  all,  distinct  from  the  body, 
terminated  by  numerous  tentacle*  forming  many 
rows  around  the  mouth,  which  is  central.  The 
animal  seems  to  adhere  very  slightly  to  the  shell ; 
it  rapidly  passes  into  a  state  of  decomposition  after 
death,  when  the  slightest  touch  is  sufficient  to 
detach  it  from  the  shell,  in  which  nothing  is  left 
but  a  coloured  liquid  which  fills  all  its  chambers. 
The  food  of  these  animals  consists  of  different  species 
of  Polyps." 

M.  De  Blainville,  however,  states,  in  the  Ap- 
pendix to  his  Manuel  de  Malacologie,  page  649, 
that  the  animal  of  one  of  the  microscopic  genera  con- 


Fig.  205. 


The  Pearly  Nautilus,  NautiliM  Pompilitts,  Linn. 

animal  through  all  the  partitions  and  cham- 
bers of  the  shell ;  but  the  attachment  of 
the  shell  to  the  body  is  effected  by  means  of 

tained  in  his  order  Cellulacea,  viz.  Miliola,  has  no 
relation  whatever  in  its  structure  to  a  Cephalopod, 
or  Cryptodibranche.  And  more  recently  M.  Dujar- 
din has  read  a  memoir,  entitled  '  Sur  les  Symplec- 
tomeres,  ou  pretendus  Gephalopodes  microscopiques,' 
in  which  the  results  of  numerous  and  apparently 
careful  observations  on  the  soft  parts  of  different 
genera  of  the  animals  in  question  are  directly  op- 
posed to  those  of  M.  D'Orbigny. 

M.  Dujardin  carefully  studied  the  Miliolae,Vortici- 
aliae,  Rotaliae,  Truncatulinae,  Ciistellariae,  Melloniae, 
&c.  in  the  recent  and  living  state  ;  and  found  that 
the  shell'was  not  internal,  and  that  the  animal,  which 
is  absolutely  deprived  of  organs  of  locomotion  and 
even  of  respiration,  is  composed  of  a  succession  of 
joints  or  lobes,  which  go  on  increasing  successively, 
and  enveloping  each  other.  The  only  period  when 
the  soft  parts  of  the  animal  are  visible  externally, 
is  when  a  new  joint  is  produced  which  has  not  com- 
pleted the  formation  of  its  chamber.  On  breaking 
the  shell,  the  composition  of  the  animal  is  found 
to  be  as  simple  as  in  the  Planariae  or  Hydrae,  or  any 
other  animals  of  the  Acrite  sub-kingdom ;  and  on 
dissolving  the  shell  by  means  of  a  mixture  of 
alcohol  and  very  weak  nitric  acid,  the  entire  body 
is  obtained,  which  is  formed  of  a  succession  of 
articulations,  occupying  all  the  chambers ;  and 
presenting  different  aspects  in  different  genera, 
which  accord  with  the  peculiarities  of  the  shell. 

From  these  observations  it  necessarily  follows 
that  the  Foraminifera  of  M.  D'Orbigny  cannot  be 
arranged  with  the  Cephalopods,  or  even  placed  in 
the  Molluscous  Series.  M.  Dujardin,  therefore, 

Proposes  to  consider  them  as  a  distinct  class  of 
nvertebrata,  under  the  name  of  Symplectomeres ; 
and  until  further  and  better  evidence  be  adduced 
to  the  contrary,  we  shall  regard  these  minute  ani- 
mals as  having  only,  in  the  form  and  structure  of 
their  shells,  a  remote  analogical  relation  to  the 
Cephalopods. 


CEPHALOPODA. 


519 


two  strong  lateral  muscles  (d*),  which  are  in- 
serted into  the  walls  of  the  last  chamber. 
The  numerous  hollow  arms  (e,  e)  and  retrac- 
tile  tentacles  (J\f),  mentioned  in  the  general 
characters  of  the'class  are  peculiar  to  this  order, 
and  the  head  is  further  provided  with  a  large 
ligamento-muscular  plate,  or  flattened  disc,  (g,) 
which,  besides  acting  as  a  defence  to  the  open- 
ing of  the  shell,  serves  also,  in  all  probability, 
as  an  organ  for  creeping  along  the  ground, 
like  the  foot  in  the  Gasteropods.  There  are  no 
fins  or  analogous  organs  for  swimming. 

The  jaws  of  the  Tetrabranchiata  are  strength- 
ened by  a  dense,  exterior,  calcareous  coating, 
and  have  thick  dentated  margins. 

The  eyes  are  pedunculated  (h,fg.  205)  and 
of  a  simple  structure. 

There  is  no  organ  of  hearing. 

The  gills  are  four  in  number,  and  without 
branchial  hearts. 

The  circulating  system  is  provided  with  but 
one  ventricle,  which  is  systemic  or  propels 
arterial  blood. 

There  is  no  ink-bag. 

The  inferior  parietes  of  the  funnel  (i,  Jig, 
205)  are  divided  longitudinally.' 

Order  II.  DIBRANCHIATA.  Syn.  Cryp- 
todibranches,  Blainv.;  Acetabulifera,  D'Orb. ; 
plus  the  Spirulid*  and  Belemnitid*. 

In  the  Dibranchiate  Cephalopods  one  genus 
alone  (Argonauta,  Jig.  206)  has  been  hitherto 
found  in  which  the  body  is  protected  by  an 


Fig.  206. 


The  Paper  Nautilus  or  Argonaut, 
Argonauta  Argo,  Linn. 

external  shell  (a) ;  but  this,  though  symme- 
trical, and  convoluted  on  a  vertical  plane, 
consists  of  one  simple  chamber,  or  is  l  mono- 
thalamous/  and  does  not  adhere  to  the  body 
of  its  Cephalopodous  occupant,  either  by  a 
hydraulic  pipe  or  lateral  muscles.  All  the 
other  genera  of  the  Dibranchiate  Order  are 
naked ;  but  they  are  provided  either  with  an 
internal  siphoniferous  polythalamous  shell,f  or 
the  remains  of  a  shell  are  found  in  various  stages 

*  The  letter  is  placed  on  the  portion  of 
broken  shell  which  still  adhered  to  one  of  the 
lateral  muscles  in  the  specimen  taken  by  Mr.  Geo. 
Bennett,  in  the  New  Hebrides  Islands.  See  PI.  1. 
Memoir  on  the  Pearly  NatUilus,  4to.  1832. 

t  This  is  the  case  in  the  Families  Spirulidee  and 
Belemnitidce  ;  the  terms  Polythalamacea  or  Sipho- 
nifera,  therefore,  do  not  distinguish  the  preceding 


of  degradation  lodged  in  the  substance  of  the 
dorsal  part  of  the  mantle. 

The  arms  of  the  Dibranchiata  are,  properly 
speaking,  eight  in  number,  (c,  1,  2,  3,  4, 
Jig.  206,}  to  which,  in  many  genera,  two  longer 
tentacles  (d,  d,jigs.  207,  208)  are  superadded. 
Both  kinds  of  prehensile  organs  are  provided 
with  acetabula,  or  suctorious  discs  for  adhesion  ; 
and  hence  the  order  has  been  termed  Acetabu- 
lij'era. 

The  jaws  are  horny,  and  their  margins  tren- 
chant. 

The  eyes  are  sessile,  (e,  e,Jig.  207,)  and  of  a 
more  perfect  structure. 

The  organ  of  hearing  is  distinctly  developed. 
The  gills  never  exceed  two  in  number;  but 
the  branchial  circulation  is  aided  by  two  mus- 
cular ventricles,  situated  one  at  the  base  of  each 
gill ;  hence  there  are  three  distinct  hearts  in 
this  order. 

There  is  an  organ  for  secreting  and  expelling 
an  inky  fluid,  used  as  a  means  of  concealment. 
The  parietes  of  the  funnel  are   entire,   (i, 
Jigs.  206,  208.) 

Subdivision  of  the  Orders. — In  the  ancient 
periods  of  the  globe  the  Tetrabranchiate  Cepha- 
1  opods  appear  to  have  abounded  in  every  sea ;  one 
genus  only,  however,  viz.  the  Nautilus,  appears 
to  have  escaped  the  influences  which  have  ren- 
dered extinct  the  rest  of  this  once  extensive  order. 
Their  chambered  shells  are  found,  generally  in 
a  fossil  state,  in  all  the  regions  of  the  globe, 
and  at  every  elevation,  charac- 
terizing the  strata  of  the  se- 
condary formation.  In  some 
places  they  occur  in  such  pro- 
digious numbers  that  the  rocks 
appear  to  be  composed  almost 
exclusively  of  their  remains. 

Some  of  these  fossil  shells 
testify  the  immense  size  to 
which  their  animal  construc- 
tors must  have  attained:  the 
shells  called  '  Cornua  Am- 
monis,'  which  were  formed  by 
Cephalopods  resembling  the 
Nautilus,  have  been  found 
measuring  four  or  five  feet  in 
diameter;  some  of  the  straight 
chambered  shells,  called  «  Or- 
thoceratites/  exceed  four  feet 
in  length;  other  species  again  appear  not  to 
have  surpassed  the  size  of  a  grain  of  rice. 

As  the  consideration  of  these  remains,  of 
which  the  Tetrabranchiate  division  of  Cepha- 
lopods is  almost  exclusively  composed,  would 
necessarily  oblige  us  to  exceed  the  limits  allot- 
ted to  this  article,  we  shall  here  subjoin  merely 
the  characters  of  the  two  families  into  which 
they  naturally  resolve  themselves,  and  to  which 
their  distribution  appears  to  be  limited. 

or  Tetrabranchiate  Order,  nor  indicate  any  cha- 
racters peculiar  to  that  group,  or  which  are  of  ordi- 
nal importance  :  and  in  other  Molluscous  classes 
it  may  be  observed  that  modifications  of  the  shell 
fail  to  afford  indications  of  the  primary  divisions, 
which  are  uniformly  based,  as  in  the  present  arrange- 
ment of  Cephalopods,  on  the  modifications  of  the 
respiratory  system. 


520 


CEPHALOPODA. 


Fam.  1.  NAUT1LIDM,  Nautilites. 
Animal,    organized   as   described   in   the 

character  of  the  order. 
Shell  external;  spiral,  or  straight;  septa 
smooth,  and  simple;  the  last  chamber 
the  largest,  and  containing  the  animal : 
siphon  central,  or  marginal  and  in- 
ternal. 

Ex.  GENERA   Nautilus,  Lamarck;    Cly- 

menes,    Munster ;      Campulites,     Des- 

hayes;  Lituites,  Breyn;  Orthoceratites, 

Breyn. 

Fam.  2.  AMMONITID&,    Ammonites, 

Snake-stones. 
Animal  unknown,  presumed  to  resemble 

the  Nautilus. 

Shell  external ;  spiral  or  straight ;  septa 
sinuous,  and  with  lobated  margins; 
the  last  chamber  the  largest  and  lodg- 
ing the  animal :  siphon  central,  or  mar- 
ginal and  external. 

Ex.  GENERA.  Baculites,  Lamarck  ;  Ha- 
mites,  Parkinson ;  Scaphites,  Parkin- 
son ;  Ammonites,  Bruguiere ;  Turru- 
lites,  Lamarck. 

The  Dibranchiate  Order  of  Cephalopods 
also  had  its  representatives  in  the  seas  of  the 
ancient  world,  as  the  shells  called  Belemnites, 
or  thunder-stones,  the  fossil  shells  of  the  Sepiae 
discovered  by  Cuvier,  and  the  horny  rings  of 
the  acetabula  found  by  Buckland  in  the  fossil 
faeces  of  Ichthyosauri,  sufficiently  testify;  but 
our  knowledge  of  this  order  is  chiefly  founded 
on  observation  of  existing  species.  These  are 
extremely  numerous;  they  frequent  the  seas 
of  every  clime,  from  the  ice-bound  shores  of 
Boothia  Felix  to  the  open  main,  and  floating 
Sargasso  or  gulf-weed  of  the  Equator;  theyseem, 
however,  to  be  most  abundant  in  temperate  lati- 
tudes. Many  species  frequent  the  coasts,  creep- 
ing among  the  rocks  and  stones  at  the  bottom  ; 
others  are  pelagic,  swimming  well,  and  are 
found  in  the  ocean  at  a  great  distance  from 
land. 

The  Dibranchiata  present  great  variety  of 
size,  and  although  the  bulk  of  the  gigantic 
species  has  been  undoubtedly  exaggerated,  yet 
the  organization  of  this  order  is  favourable 
to  the  attainment  of  dimensions  beyond  those 
presented  by  the  individuals  of  any  other 
group  of  Invertebrate  animals.  The  remains 
of  the  large  Uncinated  Calamary  caught  by 
Banks  and  Solander  in  the  Southern  Ocean, 
parts  of  which  are  still  preserved  in  the 
Hunterian  Museum,  and  the  fragment  of  the 
Cephalopod  weighing  one  hundred  pounds, 
taken  by  the  French  naturalists  in  the  Atlantic 
Ocean  under  the  line,  and  preserved  in  the 
Museum  of  the  Garden  of  Plants  at  Paris, 
afford  indubitable  testimony  of  the  formidable 
size  to  which  some  individuals  of  this  order 
attain. 

The  species  included  in  the  higher  divi- 
sion of  Cephalopods  very  naturally  resolve 
themselves  into  those  which  possess  the  eight 
ordinary  arms,  forming  the  tribe  Octopoda ; 
and  into  those  which  have  the  additional  pair 
of  elongated  tentacles,  forming  the  tribe  De- 
capoda. 


The  Decapods  are  further  characterized  by 
having  a  pair  of  fins  attached  to  the  mantle ; 
by  having  the  funnel  either  adherent  at  the 
antero-lateral  parts  of  its  base,  and  without  an 
internal  valve,  or  articulated  at  the  same  part 
by  two  ball-and-socket  joints  to  the  mantle,  and 
provided  with  a  valve  internally  at  its  apex ; 
by  having  fleshy  appendages  to  the  branchial 
hearts,  and  glandular  appendages  to  the  biliary 
ducts;  by  having  generally  a  single  oviduct, 
with  detached  superadded  glands  ;  and,  lastly, 
by  the  shell  or  its  rudiment  being  single,  mesial, 
and  dorsal. 

The  Decapodous  tribe  is  that  which  is  most 
nearly  allied  to  the  Tetrabranchiate  Order.  This 
affinity  is  not  only  indicated  by  the  additional 
number  of  external  arms,  and  the  frequent  de- 
velopment of  an  internal  circular  series  of  eight 
short  labial  tentacles,  but  by  several  internal 
characters ;  as  the  single  oviduct  and  detached 
glands  for  secreting  the  nidamentum ;  the  valve 
of  the  funnel;  the  laminated  rudiment  of  a 
chambered  shell  in  the  Cuttle-fish,  and  the  fully 
developed  chambered  and  siphoniferous  shell 
of  the  Belemnites  and  Spirula.  The  observa- 
tions of  Peron  and  Lamarck  having  proved 
that  the  animal  of  the  Spirula  possesses  eight 
short  arms  and  two  long  tentacles,  all  provided 
with  acetabula,  like  the  Sepia,  we  regard  it 
as  the  type  of  the  first  family  of  the  Decapo- 
dous Tribe,  or  that  which  immediately  succeeds 
the  Tetrabranchiata. 
Tribe  DECAPODA. 
Fam.l.  SPIRULIDJE. 

Animal,  corresponding  in  external  form 
to  the  Decapodous  type;  internal  or- 
ganization unknown,  presumed  to  be 
Dibranchiate. 

Shell  partly  internal ;  cylindrical,  multilo- 
cular,  discoid;  the  whorls  separated; 
septa  transverse,  concave  next  the  out- 
let, and  with  regular  intervals. 
Siphon  marginal  and  internal,  uninter- 
rupted. 

Genus  SPIRULA,  Lam. 
The  character  of  the  family  is  also  that  of 
the  single  genus  of  which  it  is  at  present 
composed. 

Ex.  Spirula  Australis,  Lam. 
Fam.  2.  BELEMNITID&,  Belemnites, 

Thunder-stones. 
Animal  unknown.* 

Shell  internal,  composed  of  an  external 
calcareous  sheath  formed  by  a  succes- 
sion of  hollow  cones,  the  exterior  being 
the  largest;  of  an  internal  horny  sheath, 
also  of  a  conical  form,  containing  at  its 
apex  a  chambered  shell,  the  septa  of 

*  As  it  is  certain  that  the  animals  of  this  family 
of  extinct  Cephalopods  possessed  the  ink-bag,  they 
must  consequently  have  been  enveloped  by  a  mus- 
cular mantle  ;  and  we  may,  therefore,  infer  that 
they  resembled  the  Dibranchiates  in  their  locomo- 
tive and  respiratory  organs,  and  consequently  in 
the  general  plan  of  their  organization.  In  the 
structure  and  position  of  their  siphoniferous  came- 
rated  shell  they  are  intermediate  to  Spirula  and 
Sepia,  and  as  the  animal  of  Spirula  is  proved  to  be 
a  Decapod,  the  probability  is  very  strong  that  the 
animal  of  the  Belemnite  was  of  the  same  type. 


CEPHALOPODA. 


521 


which  are  concave  externally  and  perfo- 
rated by  a  marginal  and  ventral  siphon. 

Genus  BELEMNITES,  Lamarck.* 
Fam.  3.  SEP  I  ADM,  Cuttle-fishes. 

Animal,  body  oblong,  depressed,  with  two 
narrow  lateral  fins  extending  its  whole 
length. 

Shell  internal,  lodged  in  a  sac  in  the  back 
part  of  the  mantle,  composed  of  an  ex- 
ternal calcareous  apex  or  mucro,  of  a 
succession  of  calcareous  laminae  with 
intervening  spaces  filled  with  air,  and 
supported  by  columns,  but  not  perfo- 
rated by  a  siphon,  and  an  internal  horny 
layer,  corresponding  to  the  anterior 
horny  sheath  of  the  Belemnites. 

Genus  SEPIA,  Cuv. 

The  character  of  the  family  is  also  that  of 
the  single  genus  at  present  composing 
it;  we  may,  however,  add  under  this 
head  that  the  mantle  is  free  at  its  an- 
terior margin  ;  and  that  the  acetabula 
are  supported  by  horny  hoops  with  the 
margin  entire,  or  very  minutely  denti- 
culated. 

Ex.  Sepia  qfficinalis,  Linn,  the  common 
Cuttle-fish.  (Fig.  207.) 


Fig.  207 


Fam.  4.   TEUTHIDJR*  Calamaries. 

Animal,  body  sometimes  oblong  and  de- 
pressed, generally  elongated  and  cylin- 
drical ;  with  a  pair  of  fins  varying  in  their 
relative  size  and  position,  but  generally 
broad,  shorter  than  thebod  y,and  terminal. 

Shell  internal,  rudimental,  in  the  form  of 
a  thin,  straight,  elongated,  horny  lamina; 
encysted  in  the  substance  of  the  dorsal 
aspect  of  the  mantle. 

A .  Funnel  with  an  internal  valve,  and  arti- 
culated at  its  base  to  two  ventro-lateral 
cartilaginous  prominences  of  the  mantle. 

Genus  SEPIOTTUTHIS,  Blainville. 

Body  oval,  flattened,  with  narrow  lateral 
fins,  extending  its  whole  length ;  ante- 
rior margin  of  the  mantle  unattached. 
Horny  hoops  of  the  acetabula  with  den- 
ticulated margins.  Gladius,  or  rudi- 
mental shell,  long  and  wide. 

Ex.  Sepioteuthis  loliginifbrmis,  Ruppel. 

Genus  LOLIGO,  Cuvier. 

Body  elongated,  cylindrical,  provided  with 
a  pair  of  rhomboidal  or  triangular  fins, 
shorter  than  the  body,  and  terminal, 
their  apices  generally  converging  to  a 
point,  and  united  to  the  end  of  the  man- 
tle; anterior  margin  of  the  mantle  free. 
Horny  hoops  of  the  acetabula  denticu- 
lated. Gladius  long  and  narrow. 

Ex.    Loligo  vulgaris,  Cuv.  the   common 
Calamary  or  Pen-fish.     ( Fig.  208.) 
Fig.  208. 


*   Also  the  fossil  genera,  Actinocamax ,  Miller ; 
Pseudobelus,  Blainville. 
VOL.  I. 


The  Calamary,  Loligo  vulgaris,  Cuv. 
*  From  the  term  TtvQot;  applied  by  Aristotle  to 
the   ten-armed    Malakia    with   an   internal    horny 
plate  or  yladius. 

2  M 


522 


CEPHALOPODA. 


Genus  ONYCHOTEUTHIS,  Lichtenstein. 
Body  and  fins  as  in  the  genus  Loligo  ; 
ventro-lateral  cartilages  of  the  mantle 
long  and  narrow ;  horny  hoops  of  the 
tentacular,  and  sometimes  of  the  bra- 
chial,  acetabula  produced  into  the  form 
of  hooks  or  claws.  (  Fig.  215.)  Gla- 
dius  long,  broadest  in  the  middle. 

Genus  ROSSIA,  Owen.  Body  short  and 
rounded ;  cephalic  margin  of  the  mantle 
free ;  fins  advanced,  short,  circular,  ses- 
sile, distant  and  subdorsal.  Gladius 
short  and  narrow. 

Ex.  Rossia  palpebrosa,  Owen. 

Genus  SEPIOLA,  Leach.  Body  rounded, 
short;  anterior  margin  of  the  mantle 
adherent  to  the  back  of  the  head  ;  fins 
advanced,  circular,  short,  subpeduncu- 
late,  distant  and  subdorsal.  Gladius 
short  and  narrow. 

Ex.  Sepiola  Rondeletii,  Leach. 

B.  Funnel  unprovided  with  an  internal 


valve,  and  adherent  at  the  antero-lateral 
parts  of  its  base  to  the  mantle. 

Genus  LOLIGOPSIS,  Lamarck. 

Body  long  arid  cylindrical,  terminated  by  a 
pair  of  conjoined  large  round  fins,  forming 
generally  a  circular  disc ;  anterior  border 
of  the  mantle  adherent  to  the  back  part 
of  the  head  for  a  small  extent.  Tenta- 
cula  very  long  and  slender,  (frequently 
mutilated.)  Gladius  long,  narrowest  in 
the  middle,  dilated  posteriorly. 

Ex.  Loligopsis  Veranii,  Ferussac.  (Fig. 
209;  D  the  gladius  or  rudimental 
shell.) 

Genus  CRANCHIA,  Leach.  Body  elon- 
gated, sacciform;  anterior  margin  of 
the  mantle  adherent  to  the  back  of  the 
head.  Fins  short,  rounded,  subpedun- 
culate,  approximate,  dorsal,  and  sub- 
terminal.  Gladius  long  and  narrow. 

Ex.  Cranchia  scabra,  Leach. 
Tribe    OCTOPODA.     The    Dibranchiate 


Fig.  209. 


Loligopsis   Veranii. 


CEPHALOPODA. 


523 


Octopods,  besides  wanting  the  long  tentacula, 
are  also  characterized  by  the  absence  of  man- 
tle-fins, and  consequently  are  limited  to  retro- 
grade progression  while  swimming ;  their  ace- 
tabula  are  sessile  and  unarmed ;  they  have  two 
oviducts,  but  without  detached  glands  for  secre- 
ting a  nidamentum. 
Family  TESTACEA. 

Body  oblong,  rounded ;  mantle  adhering 
posteriorly  to  the  head  ;  first,  or  dorsal 
pairs  of  arms  dilated  and  membranous 
at  the  extremity;  fc,  1,  fig.  206.) 
Funnel  without  a  valve,  but  articulated 
at  its  base  by  two  ball-and-socket  joints 
to  the  inner  sides  of  the  mantle.  Bran- 
chial hearts  with  fleshy  appendages. 
No  internal  horny  or  testaceous  rudi- 
ments ;  but  an  external  monothalamous, 
symmetrical  shell,  containing,  but  not 
attached  to,  the  body  of  the  animal; 
which  also  deposits  its  eggs  in  the  cavity 
of  the  shell. 

Genus  ARGONAUTA,  Linnaeus.  On  the 
supposition  that  the  shell  is  parasitically 
occupied  by  the  Cephalopod,  but  formed 
by  some  other  mollusk,  some  natu- 
ralists limit  the  above  generic  title  to 
the  shell,  and  call  the  Cephalopod 
Ocythoe*  We  shall,  however,  con- 
tinue to  apply  the  term  Argonauta  to  the 
Cephalopod  in  question,  as  the  evidence, 

Fig. 


though  strong,  is  not  conclusive  of  its 
parasitic  nature.  The  character  of  the 
Family  is  also  that  of  the  Genus. 

Ex.  Argonauta  Argo,  Linn.  (Jig.  206.) 

Genus  Belerophon,  founded  on  the  fossil 
remains  of  a  shell  resembling  in  family 
characters  that  of  the  Argonauta. 

Ex.  Belerophon  apertus,  Sowerby. 
Family  NUDA. 

Body  generally  rounded,  mantle  broadly 
continuous  with  the  back  of  the  head. 
Arms  connected  at  the  base  by  a  broad 
web  :  first  pair  elongated,  and  gradually 
narrowing  to  a  point.  Funnel  without 
an  internal  valve  or  external  joints; 
branchial  hearts  without  fleshy  appen- 
dages ;  biliary  ducts  without  follicular 
appendages.  Shell  represented  by  two 
short  rudimental  styles,  encysted  in  the 
dorso-lateral  parts  of  the  mantle. 

Genus  OCTOPUS,  Leach.  The  arms  pro- 
vided with  a  double  alternate  series  of 
sessile  acetabula. 

Ex.  Octopus  vulgaris,  Cuv.  the  Poulp  or 
Preke,  (fig.  210,  in  which  this  species 
is  represented  in  the  act  of  creeping  on 
the  shore  ;  its  body  being  carried  verti- 
cally in  the  reverse  position  with  the 
head  downwards ;  its  back  being  turned 
to  the  spectator,  towards  whom  it  is 
supposed  to  be  advancing.) 


210. 


The  Poulp,  Octopus  vulgaris,  Cuv. 


*  Should  the  above  suspicion  be  proved  to  be 
well  founded,  we  conceive  that  it  would  be  more 
appropriate  to  retain  the  term  Argonauta,  in  order 


to  designate  the  Cephalopod  which  navigates  the 
frail  bark  ;    and    revert   to    the    original   name    of 
Cymbium  for  the  shell,  which   was  applied  to  it  by 
2  M  2 


524 


CEPHALOPODA. 


Fig.  211. 


Genus  ELEDONE,  Leach.  The  arms  pro- 
vided with  a  single  series  of  sessile 
acetabula. 

Ex.  Eledone  cirrosa,  Leach. 
Internal  cartilaginous  parts,  or  Endo- 
skeleton. — In  the  Gasteropodous  Mollusks  the 
cerebral  orsupra-oesophageal  ganglions  are  pro- 
tected by  a  dense  membrane  which  has  been 
compared  to  a  dura  mater,  but  which  may  be 
regarded  with  more  propriety  as  representing 
the  membranous  condition  of  the  skull  in  the 
embryo  of  the  vertebrate  animal ;  and  which, 
in  fact,  assumes  a  cartilaginous  texture  in  some 
of  the  higher  organized  Pectinibranchiata, 
forming  in  them  the  unquestionable  rudiment 
of  a  true  internal  skeleton. 

In  the  present  class  a  thick  cranial  cartilage 
not  only  protects  the  cephalic  masses  of  the 
nervous  system ;  but  it  is  enlarged  and  extended 
in  different  directions,  so  as  to  afford  a  basis  of 
attachment  to  the  principal  muscular  masses  of 
the  body :  thus  fulfilling  the  second  important 
function  of  an  internal  skeleton. 

In  the  Nautilus  it  consists  of  one  principal 
cartilage,  (Jig.  211,)  which  is  situated  on  the 
ventral  aspect  of  the 
oesophagus ;  two  pro- 
cesses (a  a)  extend 
from  the  posterior  or 
dorsal  angles  on  each 
side  of  the  oesophagus 
as  far  as  the  optic  gan- 
glions. A  deep  semi- 
circular groove  (6) 
extends  along  the  an- 
terior part  of  these 
processes  for  the  lodg- 
ment of  the  optic 
ganglions  and  the  an- 
terior nervous  collar 
surrounding  the  oeso- 
phagus.  Two  other 

Internal  Cartilage  or  processes  (c  c)  arise 
Skeleton  of  the  Nautilus.  from  the  ventral  angles  • 

of  the   cartilage  and 

give  support  to  the  sides  of  the  base  of  the 
funnel.  A  middle  process  is  extended  some 
way  between  the  two  great  muscles  which  are 
inserted  into  the  shell.  The  central  part  or 
body  of  the  cartilage  (d)  is  excavated  for  the 
reception  of  the  venous  blood  returned  from 
the  head  and  funnel,  and  from  this  sinus  the 
great  dorsal  vein  commences. 

In  the  Dibranchiate  Cephalopods  the  inter- 
nal cartilaginous  skeleton  consists  of  a  greater 

Gualtieri,  when  he  first  separated  it  genetically 
from  the  Chambered  Nautilus.  In  either  case,  as 
the  grounds  for  constituting  the  new  family  of  Oc- 
topoda  now  proposed  are  derived  from  important 
organic  differences,  as  manifested  in  the  structure 
of  the  funnel  and  the  branchial  hearts,  the  claims 
of  the  Cephalopod  to  form  the  type  of  such  a  group 
would  not  be  destroyed  by  the  proof  of  the  shell 
forming  no  part  of  its  structure.  We  cannot,  how- 
ever, retain  both  the  genera  Argonauta  and  Ocy- 
thoe,  as  in  the  Families  Naturelles  du  Regne  Animal 
of  Latreille,  p.  168;  since,  if  the  shell  in  question 
be  not  secreted  by  the  Cephalopod,  its  analogy  to 
that  of  the  Carinaria  would  indicate  its  real  con- 
f  tructor  to  belong  to  the  Heteropodous  Mollusks. 


number  of  pieces,  and  has  a  more  important 
share  in  the  organization  and  functions  of  the 
animal.  We  shall  describe  it  principally  as  it 
exists  in  the  Cuttle-fish  (Sepia  Officinalis). 

The  cranial  cartilage  (A,  fg.  212)  is  no 
longer  limited  in  its  position  to  the  under  side 
of  the  oesophagus,  but  completely  surrounds 
that  tube,  which,  together  with  the  inferior  sali- 
vary ducts,  and  the  cephalic  branches  of  the 
aorta,  traverses  a  narrow  passage  in  the  centre. 
It  is  expanded  above  into  a  cavity,  which  en- 
closes and  protects  the  brain ;  while,  below  the 
oesophagus,  the  dense  cartilage  is  excavated  to 
form  the  two  vestibular  cavities  of  the  organ 
of  hearing ;  at  the  sides  it  is  developed  into 
broad  and  thick  concave  processes,  which  form 
the  back  part  of  the  orbits. 

In  the  subjoined  figure  A  is  the  cranial  car- 
tilage as  seen  from  above : — 

a  is  the  superior  part  which  protects  the  brain. 

bj  6,  are  the  two  large  optic  foramina. 

c,  c,  the  posterior  and  inferior  thick  ex- 
panded orbital  process. 

</,  d,  the  thin  and  long  anterior  and  inferior 
cartilage  which  supports  the  eye-ball,  and  is 
analogous  to  the  cartilaginous  eye  pedicle  of 
the  Rays  and  Sharks  :  these  processes  are  com- 
pared by  Meckel  to  the  superior  maxillae ;  they 
do  not  exist  in  the  Octopods,  and  are  compa- 
ratively much  smaller  in  the  Calamaries  than 
in  the  Cuttle-fish. 

e,  the  anterior  aperture  of  the  canal  through 
which  the  oesophagus  passes. 

f,  a  process,  continued  from  the  anterior 
part  of  the  cranial  cartilage,  which  expands 
into  a  broad  transverse  plate,  with  a  slight  con- 
cavity directed  forwards,  and  gives  attachment 
to  the  muscles  of  the  arms:  this  cartilage 
Meckel  compares  to  the  lower  jaw,  but  the 
analogy  is  not  more  satisfactory  than  in  the 
preceding  instance. 

The  infundibular  or  nuchal  cartilage  (B), 
which  is  a  process  of  the  cranial  cartilage  in 
the  Nautilus,  is  in  the  Dibranchiates,  and  es- 
pecially the  Cuttle-fish,  a  distinct  piece,  of 
large  size,  and  of  a  flattened  triangular  figure, 
situated  above  the  base  of  the  funnel,  with  its 
apex  directed  forwards  and  its  posterior  angles 
turned  backwards :  it  has  a  moderately  deep 
furrow  along  the  middle  of  its  upper  surface. 
In  the  Sagittated  Calamary  this  important  car- 
tilage consists  of  three  portions,  a  middle  elon- 
gated one,  having  on  its  dorsal  surface  a  mesial 
longitudinal  groove,  and  two  lateral  longitudinal 
ridges  which  are  adapted  to  a  corresponding 
ridge  and  two  grooves  in  the  under  part  of  the 
sheath  of  the  gladius,  which  sheath  here  assumes 
a  dense  cartilaginous  consistence  :  from  the  an- 
terior extremity  of  the  middle  nuchal  cartilage 
two  flattened  cartilages  extend  outwards  and 
backwards,  and  then  curve  slightly  inwards. 
These  correspond  to  the  dilated  base  of  the  carti- 
lage in  the  Sepia,  protect  the  great  lateral  nerves 
of  the  mantle,  and  give  origin  to  the  lateral 
muscles  which  are  perforated  by  the  nerves. 

On  each  side  of  the  base  of  the  funnel 
there  is  a  smooth  oblong  articular  cavity  which 
is  formed  by  a  distinct  cartilage  (C) ;  it  is 
adapted  to  receive  a  corresponding  cartilagi- 


CEPHALOPODA. 


525 


Fig.  212. 


Skeleton  of  the  Cuttle-fah. 


nous  prominence  arising  from  the  inner  sur- 
face of  the  sides  of  the  mantle.  This  pro- 
minence in  the  Sepia  is  of  an  oval  shape ;  but 
in  the  Teuthida  it  forms  a  narrow,  elongated, 
cartilaginous  ridge,  and  is  adapted  to  a  cor- 
responding groove  at  the  sides  of  the  funnel. 
In  the  Calamary  the  ridge  is  of  the  same  size 
with  the  groove  ;  but  in  the  Onychoteuthis  the 
ridge  or  antero-lateral  cartilage  commences  at 
the  anterior  margin  of  the  mantle,  and  extends 
downwards  some  way  below  the  termination  of 
the  infundibular  groove.  Rathkc*  discovered 
in  the  corresponding  part  of  the  mantle  of  the 

*  Memoires  de  1'Acad.    Imp.   des   Sciences  de 
Petersbourgh,  torn.  ii.  pt.  1  et  2,  p.  154. 


Loligopsis,  viz.  on  either  side  and  towards 
the  ventral  aspect,  a  thick,  opaline,  elongated 
cartilage,  extending  longitudinally  for  more 
than  half  the  length  of  the  mantle,  and  sup- 
porting a  series  of  wart-like  processes.  These 
lateral  tuberculated  cartilages  in  Loligopsis  we 
regard  as  corresponding  to  the  lateral  ridges  in 
the  Calamaries  and  Onychoteuthis  above-men- 
tioned ;  but  in  the  Loligopsis  they  are  not  arti- 
culated with  the  sides  of  the  funnel,  which  are 
otherwise  attached  to  the  mantle.  In  all  the 
Decapods,  however,  this  pair  of  cartilages  on 
the  ventro-lateral  aspects  of  the  mantle  is  more 
or  less  developed. 

In  the  Sepia  a  longitudinal  cartilage  is 
situated  on  the  ventral  aspect  of  the  liver. 
The  long  lateral  fins  are,  in  the  same  genus, 
each  supported  by  a  narrow,  flattened,  elon- 
gated, cartilaginous  plate  (D,  D,  jig.  212); 
pointed  at  its  anterior  extremity,  obliquely 
truncate  behind;  smooth  and  gently  concave 
internally  fgj),  but  traversed  by  an  irre- 
gular longitudinal  ridge  (h)  on  its  external 
surface.  These  cartilages  form  the  points  of 
attachment  to  the  powerful  muscles  of  the 
lateral  fins.  From  the  dorsal  ridge  of  each 
cartilage  a  number  of  close-set  fibro-cartila- 
ginous  laminae  extend  at  right  angles  to  the 
cartilage  to  near  the  margin  of  the  fin,  with 
their  plane  in  the  direction  of  the  axis  of  the 
body  :  they  alternate  with  the  strata  of  mus- 
cular fibres,  resembling  the  rays  which  support 
the  fins  of  fishes. 

The  analogy  of  this  structure  to  the  cartila- 
ginous basis  of  the  great  pectoral  fin  of  the  Ray 
is  so  close  and  satisfactory  that  we  can  scarcely 
hesitate  to  acknowledge  the  locomotive  appen- 
dages of  the  mantle  in  the  Decapodous  Cepha- 
lopods  as  representatives  of  the  pectoral  fins  of 
fishes,  and  consequently  of  the  anterior  extre- 
mity of  the  vertebrated  animal.  As  they  are 
not,  however,  fixed  to  a  vertebral  column,  their 
situation  is  not  constant,  being  sometimes,  as 
in  Rossia,  situated  towards  the  anterior  part  of 
the  body;  sometimes,  as  in  Loligo,  placed  at 
the  posterior  extremity ;  just  as  we  perceive  the 
ventral  fins  of  Fishes  shifting  their  position,  in 
consequence  of  a  similar  want  of  connexion, 
so  as  to  occupy,  in  some  species,  a  position 
more  anterior  even  than  the  pectoral  fins,  with- 
out losing  their  essential  character,  as  the  ana- 
logues of  the  posterior  extremities. 

The  cartilages  of  the  fins  correspond  in  length 
to  the  parts  which  they  support,  and  are  con- 
sequently much  longer  in  the  Cuttle-fish  than 
in  the  Calamaries;  in  the  Octopods  they  are 
entirely  wanting. 

Locomotive  System.  —  The  organs  of  loco- 
motion in  the  Cephalopods  are  of  two  kinds, 
one  consisting  of  appendages  developed  from 
the  head  ;  the  other  of  rudimental  fin-like  ex- 
tremities developed  from  the  trunk ;  the  latter 
organs  are  confined,  as  we  have  seen,  to  the 
Decapodous  genera  of  the  higher  or  Dibran- 
chiate  Order. 

The  cephalic  processes,  which  are  called 
digitations,  arms,  feet,  tentacles,  and  pedun- 
cles, have  no  real  homology  with  the  loco- 
motive extremities  of  the  Vertebrata ;  to  these 
they  are  analogous  only,  inasmuch  as  they 


526 


CEPHALOPODA. 


have  a  similarrelation  of  subserviency  to  the  loco- 
motive and  prehensile  faculties  of  the  animal. 

Among  the  Vertebrates  traces  of  organs  corre- 
sponding to  these  cephalic  feet  are  met  with 
principally  in  the  class  of  Fishes,  in  the  form 
of  tentacles  developed  from  the  lips ;  and 
Schultze,  a  learned  German  Naturalist,*  has 
indicated  the  close  affinity  which  the  Cyclo- 
stomous  Fishes  bear,  in  this  respect,  to  the 
Cephalopods;  in  one  genus,  viz.  Gastro- 
branchus,  or  Alyxine,  eight  free  filaments  are 
extended  forwards  from  the  circumference  of 
the  funnel-shaped  orifice  of  the  mouth,  repre- 
senting the  eight  ordinary  arms  of  the  Cepha- 
lopoda Dibranchiata,  but  arrested  in  their  de- 
velopment because  of  the  pre- 
ponderating size  of  the  caudal  ,,. 
extremity  of  the  body,  which 
now  forms  the  sole  locomotive 
organ.  The  expanded  sucker 
anterior  to  the  jaws  of  the 
Lamprey  may,  in  like  manner, 
be  considered  to  represent  the 
united  bases  of  the  cephalic 
feet  of  the  class  under  consi- 
deration. 

In  the  Nautilus  the  cephalic 
organs  of  prehension  and  loco- 
motion consist  of  slender  sub- 
cylindrical  annulated  tentacles, 
which  are  sheathed  and  retrac- 
tile, (fig.  213,)  like  those  of 
some  of  theGasteropodousMol- 
lusks,  as  Dan's,  Thethys,  and 
Tritonia.  Here,  however,  they 
astonish  the  observer  by  their 
unexampled  number,  sur- 
rounding the  mouth  in  suc- 
cessive series,  and  amounting 
to  little  short  of  a  hundred. 
These  tentacles  are  divided  into 
three  kinds,  according  to  their 
situation,  viz.  *  brachial  or 
digital/  *  ophthalmic,'  and 
'  labial:'  the  latter  being 
again  subdivided  into  '  ex- 
ternal '  and  *  internal.' 

The  brachial  tentacles  are 
forty  in  number,  and  are  sup- 
ported by  short  conical  trihe- 
dral hollow  processes  or  digita- 
tions,  (e,  e,Jig.  205,)  of  which 
the  two  superior  or  dorsal  ones 
are  conjoined  and  dilated  into 

•  i-   %  -  • 

a  muscular  disk  covering  the 
whole  upper  part  of  the  head,     jv«t/ri/«.    Pom- 
(f?  g>fg-  205;)  *«  remaining  pilna. 

thirty-eight  are  disposed  ir- 
regularly, nineteen  on  either  side,  one  over- 
lapping another,  and  all  directed  forwards,  con- 
verging towards  the  orifice  of  the  oral  cavity, 
in  which  the  jaws  and  mouth  are  concealed. 
The  longest  of  these  dictations,  when  its  free 
extremity  only  is  measured,  does  not  equal  one 
inch;  but  externally  they  appear  longer,  be- 
cause they  adhere  for  some  way  to  the  sides  of 
the  head.  The  digitations  present  no  trace  of 


1818. 


Meckel  Archiv.  fur  Physiologic,  B.  iv.  p.  338. 


acetabula  or  suckers,  but  are  perforated  at  the 
extremity  by  a  canal  (a,  «,  Jig.  213,)  which  is 
continued  far  into  the  substance  of  the  head  to 
near  the  cerebral  ring ;  the  tentacle  (6)  which 
is  lodged  in  this  canal,  is  consequently  longer 
than  the  digitation  from  which  it  is  protruded. 

The  labial  tentacles,  forty-eight  in  number, 
extend  from  orifices  situated  on  the  anterior 
margins  of  four  broad  flattened  processes, 
arising  from  the  inner  surface  of  the  oral 
sheath  opposite  the  base  of  the  mandibles. 
Two  of  these  processes  (a,  «,  Jig.  219)  are 
superior,  posterior,  and  external  in  situation ; 
the  other  two,  (b,  bjjig.  219,)  which  are  smaller, 
are  inferior,  anterior,  and  more  immediately 
embrace  the  jaws,  and  they  are  connected  to- 
gether by  a  lamellated  organ  ('c,i//g.2!9),  after- 
wards to  be  described.  Each  of  these  *  labial' 
processes  is  pierced  by  twelve  canals  contain- 
ing the  tentacles  in  question  :  they  differ  from 
the  digital  tentacles  only  in  relative  size,  and 
in  being  of  a  softer  and  more  delicate  texture. 

The  ophthalmic  tentacles  seem  more  ex- 
pressly designed  as  instruments  of  sensation ; 
they  do  not  possess  the  strength  requisite  for 
prehensile  purposes,  and  are  not  situated  con- 
veniently for  locomotive  actions;  they  are  four 
in  number,  and  project  laterally  one  before  and 
one  behind  each  eye,  involuntarily  reminding 
the  observer  of  the  antennae  in  Crustacea,  &c. 
At  first  sight  they  seem  annulated  like  the 
brachial  and  labial  tentacles ;  but  upon  a  closer 
examination,  they  are  found  to  consist  of  a  num- 
ber of  flattened  circular  disks  closely  packed 
upon  a  lateral  stem,  a  structure  which  is  sin- 
gularly analogous  to  that  of  the  antennae  of 
the  Lamellicorn  Beetles.  In  this  respect,  how- 
ever, the  Pearly  Nautilus  does  not  stand  alone 
in  the  Molluscous  series,  the  retractile  tentacula 
of  the  Doris  present  a  very  similar  structure. 

The  fibres  of  the  dense  musculo-ligamentous 
sheath  (d,  d,  fg.  219),  which  incloses  the  man- 
dibles and  supports  the  eyes  and  digital  pro- 
cesses, arise  from  the  whole  of  the  anterior 
and  outer  part  of  the  cartilaginous  skeleton 
above  described.  They  were  so  densely  in- 
terwoven in  the  specimen  we  dissected  as  to 
preclude  the  possibility  of  ascertaining  their 
exact  course  or  arrangement. 

The  large  lateral  muscles  of  the  funnel  come 
off  principally  from  the  infundibular  processes 
of  the  internal  cartilage.  There  are  also  two 
small  round  and  distinct  muscles  designed  to 
draw  the  funnel  closer  to  the  head,  they  pass 
to  their  insertion  through  canals  excavated  in 
the  sides  of  the  funnel. 

The  fleshy  masses  which  proceed  backwards 
from  the  posterior  part  of  the  skeleton  are  the 
two  great  muscles  (6,  6,  ./?&'.  231,)  which  attach 
the  Nautilus  to  its  shell.  These  are  inserted 
by  obliquely  truncated  flattened  extremities 
into  a  layer  of  homy  substance  which  is 
closely  adherent  to  the  inner  surface  of  the 
sides  of  the  last  chamber  of  the  shell  at  a  little 
distance  from  die  septum  forming  its  base : 
where,  in  recent  specimens,  these  impressions 
are  always  to  be  plainly  seen.  The  part  which 
passes  through  the  perforations  of  the  septa  is 
not  a  muscular  or  tendinous  chord,  as  has  been 
conjectured,  but  a  weak  membranous  tube, 


i  i  rim  oi'ODA. 

which  can  1,-iul  but  a  feeble  assistance  111  in.iiu-  ve-ntral    pair  of  braclna  ;   thoy  proceed   at   first 

taming  tin-  shell   in  its  n.itur.il  position.  outwards  to  a  large-  membranous  cavity  situated 

The  mantle1  of  the  Nautilus   is  very  thin  and  anterioi  to  the  e  \  e-s.  and  theiie'e  emerge  between 

membranous,   excepting     :>t    Us    five    margin,  the  thml  ami  fourth  arms  on  either  sule. 
wlie-re-   it    is    provided    with    longitudinal    uuis  Tin'  acetabula  or  suckers  arc  disposed  along 

cnlar    fibre's    lor  its  retraction,  and  a  thin  e-xte-r-  tlu1  whole   exte'iit   of  tin-   inner  surface   of    the 

n;UstratunM>f  transverse  fibres,  for  tho  closing  oielmarv  arms,    but    an-   ge'ne-rally  confined    to 

ot    its  anterior   aperture,   eluring    the'   expulsion  ihiMAlivmilies  of  the  tentacles,  \\here  the\   are 

of  the  respiratory  em  rents.  closely  aggregated  on  the  inner  aspect. 

The-    large-   mandibles    (,/.   /•,  /.•„•.  ;M7:    f,   f\  Of   tlu>    elitleivnce     between    the    anus    and 

ll.O  are  sujiported  upona  tie-shy  snbstam  e  tentaeles    Aristotle    was    well    aware,    and    ac 

.  :  ;  \  and  moved    by  appropriate   urns-  cordingly,  with  his  usual  exactness,   he-  applies 

Cles.      '1'he  fimge-d  lip  i,-.  /;.•;.  •;  I  T  )    which    sur-  to   the-in'  distinct   epithets:        rio'fac  /uiv  "  • 

rounds    them    is    pro\  ideil    with  a    longitudinal  i^li    R«i  rotavc    hxwJxovc   *****    wX»»   toe   )>mc 

stiatum  of  fibres  for  its   retraetion,  and  an  exte-  w»Xwiroh»».  'ihf  >'  iyovrtv  «t  TI  rnwitti  luu  «i 

nor   oibieulai    sphnu  ter   at   its  anterior    margin.  »*1  »I  riBSti  h/«  v^ip*r«il«;  f*«Hf«^  i«r* 


The  whole  bueeal  apparatus  is  altaehed   to  "»••  i^r*(  C.*<»iAw.*     "  All  (*molha)  have 

eartda.mnous   skeleton    by  tour  strou-,    retraetor      ('<ll(  /<  '  •'.    IM~O\  uleil    w  itli    a   double    series   ot 


museles,   t\\0  abo\e  (^//,  //.   //^.  'J  17,  0  l'.>\   and  Miekers,  exeept  in  one  i^euus  of  l'o!\pi.f      The 

two  below    {i,i,    /.'/:.  ;'  1  ,'  \   and   its  base  is  sur-  'Sepuv.    Teulhules.  ami  Tenthi.*    ha\e.   bt  sides. 

rounded    by  a    tiansveise   stiatum   of  mnsenlar  lu°  'OI1!A  ^»v/v>v;</<  >,  the    extremities  of  w  IIK  h 

tibivs  (/,   //^.  -Jl«))  continued    from  the  external  ;llt'    l^'Si'l    ^»tl»    a    double   series    of    snekers." 

labial     processes,     aeross    the    upper    or    dorsal  1'bny     gives,     after     the     Slagyritt',      the     fbl- 

asjHVt    of  the    |aws,  which,    by  the  eontraelion  h>«'ini»    notice    of    their   functions.    "    Sepia-    et 

of  these  tibics,  are  piotrmleil  out\\aids.  1  oli;;ini    pedes   duo  ex  his  lont;issimi   et  aspen. 

The   tongue    (  /;.•;    -J.ii^     is    a    lan-.e    e»>mple\  o,uibns    ail    oraadmo\cnt    cibos,   t  t  in  thu  libns 

muscular    oii-.an,    the    t\tunu[\     ot     winch    is  ""'•  vt'lnt  ancons,  stabiliunt."      («erman  authois 

retracted    b\   two    pair   ot    loin-,  slender   muscles  vienerally  term  the  orilinar\  feet.  '  arms.'  {  ,.-•;.(,) 

(>!}  arism;;'from    the   •l«-nsi-  iueiubrane  eli>sin-  -"ul  »!'•«•  lentades  •  s,-i:crs,  (JtHgtrmc.) 
the    lower   part    of  the  mouth  ;   a    tlnnl    pair  of  '"    l'u'    (  '«'phalopods   winch    have    onl\     the 

muscles    (l>)    y;iven    oil'  from   (he  posterior  mai  ei-.-,lit     noimal     feet,    these     present    many    \an 

i;ms  of    the   lower    mandible    are    inserted    mti>  atious;     ami,    although    tlu  \    are   '.;cneiall\     re 

the    anterior    extremilv     of    the    homy     lingual  maikable  tor  then  length,   yet  in  some  species, 

rasp  hereafter  to  be  described.      Other   internal  as    l'u>    (!  -    lnev    are    cxlieim-ly 

mnsenlar  pails    will    be    mentioned     m    the  de  short,   resembling    the  digital    processes   of  the 

MTiption  »•('  the  visceia  to  which  tin  \    relate.  Nautilus.        In     OctO/Mli    JC^/ftM,    the    first    OT 

The    musiiilar    system    of    the    Pibranclnate  dorsal    pair    is    alone    developed    so   astosene 

Cephalopods.    like    their    internal    skeleton,   is  »-s  a  loeomotix  c  organ.  and  the  animal  must  cia\\  I 

much    more  claboralelv  developed   than    in  the  along  the  ground  by  means  of  this  pair  only. 
inferior   order     of    which    the     Nautilus    is    (he  io  TOOSl  OctOpods  the  first  pair  of  fctl  IS  the 

t\pe:    but  tho  same  plan  may  be  observed  to  -o  longest.      In     (',.,•.'..>     .1   .......    m    which    the 

vrrii  the  disposition  ot  all  the  prnu  ipal  mass,  s.  'eel     app.uentl\    juesenl     the    maximum    of  de 

A  hollow   cone  of  nuiscnlar  tibics  is  attached  ^elopm^•ut.    the  dorsal    feet    aie    ten  times,    and 

by  a  truncated    apex  to   the  anterior  margin   of  the  V*nUal  01)09  fty«  tUU@S,  the    h-ngth    ot    t!u> 

tlie    cephalu-    cartilage,    01    to    niiuvssfs  'drvr  bo,l\  .      llesitles  their  s\iueruu-  length  the  ilorsal 

IOJHH!  therefrom,   in  order  to  atlord  these  fibres  tl>t>t    pwsfnt   other  peculiarities   in   this   family 

•ni  m  creased  surface  of  origin.    The  fibres  are  °f   (•  fphalopmta.     In  the  genus  Argv***t* 

interlaced,    one    with    another,    in    a    close   .uid  (.f::^    '^1';.  «'  I  .  N  the>  aic  pi  o\  idc.l  w  ilh  expanded 

compact     manner     as      the      cone     expands     to  membranes,    the    tabled    use    ol    which    has   at 

form     the    cavity    containing      the    tlcshv     mass  fouled    a   beautiful    subject    for    poetic    in 

of    mouth;     and    at    the    anterior   uxlrcnntv    of  "'all    ages;    but    similar   appendages    occur    in 

the    mouth    (hey    are     continued    forwauls     and  <'••'•  v,    -ind    in   (  ',  .    in 

separate     into     eight    distmet     portions,    which  «hich    both    the    tnsj    and   second   pansot    t(  c( 

form  th««  arms.  snppoit     luo.ul    aiul    tlnn    nu-mbiancs    at    their 

These-    ori-.ans    are    developed     in    a    kind    of  extiemitu-s.       Now    neither   of  these  specie's  in 

mver.se  pioportion  lolheboilv,  bem  -,  i-eneralU  ,  habit    a    .shell,    in   which    the    expanded    me'in- 

as  Aristotle*    twice    takes    occasion    to   observe-.  bianes  conKI  he  useel    to  w  alt  the-  annual    aloiu; 

loilgrst     m    the     shi'rt     lound  bodn  d    (*>.,.•.    ,>i  the  sin  tace  ot    the  ocean,   as    has    been    said    or 

I'oulps,    .nut    shoite-st    m  the-  Ion:;  bo.lud  Cala  Minr.  >'l    th<     Aigon.iut   (UMII   Aristotle'  tot'ii\ie-i. 

manes,  Se-pia-.   \c.    in  vxhie'li  the-  two  e-loif.alcd  nolu  (  •'"  "iiachus  (o   l»\ron.      The  ph\  siologist. 

le-tiactde  tentacle's   (,/,  ;('S,    ?0'.n    are'  1U   I'ontemplatmg    tlu-    striutme    of  the  ve-lateel 

superaelde'd.    bv   wav   of  rompeiisalion       These  •"  llls-  ls  compelled  to  disallow   them  the  pow  t-r 

latter    oiy.ans    are-    i.nclv     eoulnmed     liom     ihe  (>l     being     maintamcil     e-re-i  t    and    expamled    to 
muscular   eo:u-    inclosinj:    the  apparatus  of  the' 

month,    but    arise    fiom    the    ceplulic   eaililagc-.  *   'l>'«'-    '»!..  iv.  c.  1.4. 

close    togethei,    internal    to    the   origins   of   the          f    I'ho  Krmi«  */,,/.••„  <.t    \  ,,s«..j!«-.  il.«-  ,  -,K!,i  i«  -,-i  ,,t 

X>  III.   tl    llA>  ,    ,MV!\    .»    Mll,.lr  s,    ,1,'s   ,'t     Ml,   U    1 

i  ^(ircio*  <H  /<M|MO  or  OalaMariMj  »i|>|-i'>(-ii 

'    Dr   HiM..fi;i    Aiiiin.Miuin.    (  K»l.  S.I.  111  -i,!,i.  l.i  |.  I..-    It,,-    /  !„,    ,.f    u.o.l 

»i«,)  lib.  iv.  ..  i.  ,•  .x  ••  MtwraUstt. 


528 


CEPHALOPODA. 


meet  the  breeze.  What  their  real  function 
may  be  is  still  to  be  determined;  but  the  re- 
moval of  the  erroneous  impressions  entertained 
on  this  subject  is  the  first  step  towards  the  at- 
tainment of  the  truth. 

In  our  common  Octopus,  and  most  other 
species  of  this  genus,  the  feet  are  connected 
together  for  some  distance  beyond  the  oral 
sheath  by  membranes  and  muscles  which  form 
a  circular  fin.  This  is  their  sole  locomotive 
organ  when  swimming;  and  by  its  powerful 
contraction  they  are  driven  through  the  water 
with  a  quick  retrograde  motion.  In  a  species 
which  we  have  recently  described*  (Octopus 
semipalmatus)  the  fin  is  extended  only  between 
the  four  dorsal  arms :  a  structure  which  must 
occasion  a  characteristic  difference  in  its  mode 
of  swimming. 

The  disposition  of  the  muscles  of  the  web- 
like  fin  is  as  follows.  There  are  two  transverse 
layers  of  fibres,  the  external  arises  from  a  white 
line  extending  along  the  back-part  of  each 
foot ;  the  internal  from  the  sides  of  the  same 
feet  between  the  attachments  of  the  suckers. 
These  two  strong  muscular  bands  are  con- 
nected together  as  they  pass  from  arm  to  arm 
in  the  middle  of  the  webs,  and  decussate  one 
another,  so  that  the  external  become  internal 
and  vice  versa.  Within  these  a  thin  layer  of 
longitudinal  fibres  extends  to  the  free  margin 
of  the  webs ;  and  there  is  also  a  layer  of  ob- 
lique longitudinal  fibres  externally,  which  arise 
from  the  white  line  at  the  middle  of  each  foot : 
these  fibres  are  shown  at  (k,  k,fig.  216,)  the 
transverse  fibres  at  /,  /. 

In  the  Cephalopods  which  possess  the  re- 
tractile peduncles,  the  ordinary  arms  are  gene- 
rally short,  and  the  first  or  dorsal  pair  are 
commonly  exceeded  in  length  by  the  second  ; 
sometimes,  indeed,  as  in  the  species  of  Loli- 
gopsis,  of  which  the  figure  is  subjoined, 
(fig  209,)  they  go  on  progressively  increasing 
in  length  to  the  ventral  or  fourth  pair,  which 
here  resembles  in  its  great  development  the 
arms  of  the  Octopods.  The  peduncles  are 
always  longer,  and  more  slender  than  the  arms; 
they  exhibit  these  characters  in  the  highest 
degree  in  the  genus  Loligopsis,  in  which  they 
are  frequently  mutilated  and  lost;  but  the 
examination  of  the  nerve  proceeding  to  the 
mutilated  stump  sufficiently  attests,  in  such 
cases,  the  importance  of  the  organ  of  which 
this  animal  has  been  accidentally  deprived. 
The  tentacles  serve  to  seize  a  prey  which  may 
be  beyond  the  reach  of  the  ordinary  feet,  and 
also  to  act  as  anchors  to  moor  the  Cepha- 
lopod  in  safety  during  the  agitations  of  a 
stormy  sea. 

Each  arm  is  perforated  near  the  centre  of  its 
axis  for  the  lodgment  of  its  nerve  (a,  fig.  214) 
and  artery  (6) ;  and  upon  making  a  transverse 
section  of  the  arm,  these  are  seen  to  be  lodged 
in  a  quadrangular  or  rhomboidal  space  (c)  of  a 
light  colour  and  apparently  soft  homogeneous 
texture,  but  in  which  a  few  radiating  fibres  may 
be  discerned.  This  part  is  surrounded  by  four 

*  See  Proceedings  of  the  Zoological  Society  for 
March,  1836. 


Fig.  214. 


Section  of  an  Arm  and  Suckers  of  a  Poulp. 

groups  of  transverse  striae  forming  as  many  seg- 
ments of  a  circle,  external  to  which  there  are 
two  thin  circular  strata  of  fibres.  On  making 
a  longitudinal  section  of  the  part  the  striated 
segments  are  seen -to  consist  of  longitudinal 
muscular  fibres,  and  of  the  surrounding  strata, 
the  fibres  of  the  internal  are  longitudinal,  and 
those  of  the  external  transverse.  It  is  easy  to 
conceive  that,  like  the  tongue  in  Mammalia, 
the  arms  thus  organized  may  be  lengthened, 
shortened,  curved,  and  bent  in  all  conceivable 
directions. 

The  acetabula  or  suckers  with  which  the  in- 
ternal surface  of  the  arms  of  the  Dibranchiates 
are  provided,  vary  in  relative  position,  in  size, 
in  structure,  and  in  mode  of  attachment,  not 
only  in  different  species,  but  in  different  arms 
in  the  same  individual,  and  sometimes  in  diffe- 
rent parts  of  the  same  arm.  Thus  in  the  pe- 
duncles of  Loligopsis  Peraniijthe  suckers  on  the 
long  cylindrical  stem  are  sessile,  while  those  on 
the  expanded  extremity  are  supported  on  long 
peduncles;  and  another  remarkable  instance 
will  presently  be  mentioned  of  suckers  having 
different  structures  for  different  functions  in  the 
same  arm. 

In  the  Dibranchiate  genera  which  are  charac- 
terized by  a  soft  thin  skin,  as  the  Argonaut, 
Octopus,  and  Eledone,  the  suckers  are  soft 
and  unarmed ;  in  those  genera  which  have  a 
hard  and  thick  skin,  as  the  Calamary  and 
Onychoteuthis,  cuticular  appendages  are  deve- 
loped in  the  cavities  of  the  suckers. 

An  excellent  description  of  the  unarmed 
acetabulum  as  it  exists  in  the  genus  Octopus,  is 
given  by  Dr.  Roget. 

The  circumference  of  the  disc  is  raised  by  a 
soft  and  tumid  margin  (e,  Jig.  214);  a  series 
of  long  slender  folds  of  membrane  (f)y  cover- 
ing corresponding  fasciculi  of  muscular  fibres, 
converge  from  the  circumference  towards  the 
centre  of  the  sucker,  at  a  short  distance  from 
which  they  leave  a  circular  aperture  (g) :  this 
opens  into  a  cavity  (h),  which  widens  as  it 
descends,  and  contains  a  cone  of  soft  substance 


CEPHALOPODA. 


539 


(i)  rising  from  the  bottom  of  the  cavity,  like 
the  piston  of  a  syringe.  When  the  sucker  is 
applied  to  a  surface  for  the  purpose  of  adhe- 
sion, the  piston,  having  previously  been  raised, 
so  as  to  fill  (he  cavity,  is  retracted,  and  a 
vacuum  produced,  which  may  be  still  further 
increased  by  the  retraction  of  the  plicated  cen- 
tral portion  of  the  disc.  So  perfect  is  the  me- 
chanism for  effecting  this  mode  of  adhesion, 
that  in  the  living  Cephalopod, "  while  the  mus- 
cular fibres  continue  contracted,  it  is  easier  to 
tear  away  the  substance  of  the  limb  than  to 
release  it  from  its  attachments  :  and  even  in  the 
dead  animal  the  suckers  retain  a  considerable 
power  of  adhesion."* 

Still  there  are  circumstances  in  which  even 
this  remarkable  apparatus  would  be  insufficient 
to  enable  the  Cephalopod  to  fulfil  all  the  offices 
in  the  economy  of  nature  for  which  it  was 
created;  and  in  those  species  which  have  to 
contend  with  the  agile,  slippery,  and  mucus- 
clad  fishes,  more  powerful  organs  of  prehension 
are  superadded  to  the  suckers. 

In  the  Calamary  the  base  of  the  piston  is 
inclosed  by  a  horny  hoop,  the  outer  and  ante- 
rior margin  of  which  is  developed  into  a  series 
of  sharp-pointed  curved  teeth.  These  can  be 
firmly  pressed  into  the  flesh  of  a  struggling 
prey  by  the  contraction  of  the  surrounding 
transverse  fibres ;  and  can  be  withdrawn  by  the 
action  of  the  retractor  fibres  of  the  piston.  Let 
the  reader  picture  to  himself  the  projecting 
margin  of  the  horny  hoop  developed  into  a 
long,  curved,  sharp-pointed  claw,  and  these 
weapons  clustered  at  the  expanded  terminations 
of  the  tentacles,  and  arranged  in  a  double  alter- 
nate series  along  the  whole  internal  surface  of 
the  eight  muscular  feet,  and  he  will  have  some 
idea  of  the  formidable  nature  of  the  carnivo- 
rous Onychoteuthis. 

Banks  and  Solander,  in  Cook's  first  voyage, 
found  the  dead  carcase  of  a  gigantic  species 
of  this  kind  floating  in  the  sea,  between 
Cape  Horn  and  the  Polynesian  Islands,  in 
latitude  30°  44'  S.  longitude  110°  33'  VV. 
It  was  surrounded  by  aquatic  birds,  which 
were  feeding  on  its  remains.  From  the  parts 
of  this  specimen,  which  are  still  preserved  in 
the  Hunterian  Collection,  and  which  have 
always  strongly  excited  the  attention  of  natu- 
ralists, it  must  have  measured  at  least  six  feet 
from  the  end  of  the  tail  to  the  end  of  the  tenta- 
cles. The  natives  of  the  Polynesian  Islands, 
who  dive  for  shell-fish,  have  a  well-founded 
dread  and  abhorrence  of  these  formidable 
Cephalopods,  and  one  cannot  feel  surprised  that 
their  fears  should  have  perhaps  exaggerated 
their  dimensions  and  destructive  attributes. 

We  cannot  quit  this  part  of  our  subject 
without  noticing  a  structure  which  adds  greatly 
to  the  prehensile  powers  of  the  uncinated 
Calamaries  :  at  the  extremities  of  the  long  ten- 
tacles, besides  the  uncinated  acetabula,  a  cluster 
of  small  simple  unarmed  suckers  may  be  ob- 
served at  the  base  of  the  expanded  part.  When 
these  latter  suckers  are  applied  to  one  another, 

*  Roget,  Bridgewater  Treatise,  i.  p.  260.  See 
also  Baker,  An  Account  of  the  Sea-Polypus,  Phi- 
losoph.  Trans,  vol.  1.  p.  777. 


Fig.  215. 


the  tentacles  are  firmly  locked  together  at  that 
part,  and  the  united  strength  of  both  the  elon- 
gated peduncles  can  be  applied  to  drag  towards 
the  mouth  any  resisting  object  which  has  been 
grappled  by  the  terminal  hooks.  There  is 
no  mechanical  contrivance  which  surpasses 
this  structure  :  art  has  remotely  imitated  it  in 
the  fabrication  of  the  obstetrical  forceps,  in 
which  either  blade  can  be  used  separately,  or, 
by  the  interlocking  of  a  temporary  joint,  be 
made  to  act  in  combination.  (See  Jig.  215, 

where  d  marks 
the  stems  of  the 
peduncles,  e 
the  parts  joined 
together  by  the 
mutual  apposi- 
tion of  the  un- 
armed suckers, 
f  the  terminal 
expanded  por- 
tions bearing 
the  hooks.) 

The  great 
muscular  coni- 
cal basis  which 
gives  origin  to 
the  feet  is  at- 
tached, as  be- 
fore mention- 
ed, to  the  an- 
terior part  of 
the  annular 
cephalic  carti- 
lage :  it  is  also 
provided  with 
distinct  fasci- 
culi of  muscu- 
lar fibres,  which 
connect  it  to 
the  mantle  and 
to  other  parts 
of  the  body.  ' 
In  the  Octo- 
pus a  great  pro- 
portion of  these 
fibres  arise  from 
the  posterior 
part  of  the  man- 
tle, and,  di- 
verging as  they 
pass  forwards, 
spread  over  the 
posterior  and 
lateral  parts  of 
the  head,  rece- 
ding at  the  sides 
to  leave  a  space 
for  the  eye ; 
they  then  di- 
vide into  five 
bundles,  each 
of  which  again 
subdivides  into 
two,  which  are 
lastly  inserted 
into  the  sides 
of  the  six  dorsal  and  lateral  feet.  (See  a,  a, 
./fe.216.) 


Arm*  and  Tentacles  of  an 
Onychoteuthis. 


530 


CEPHALOPODA. 


Fig.  216. 


Muscles  of  the  Poulp,  Octopus  Vvlgaru. 

Fasciculi  of  muscular  fibres  (b,  b,  216,)  are 
continued  from  the  ventral  pair  of  feet  and  the 
back  part  of  the  cranium,  across^  the  base  of 
the  funnel  to  the  muscular  septum,  which 
divides  longitudinally  the  branchial  cavity. 
Other  fibres  descend  to  join  the  muscular  tunic 
enveloping  the  liver  and  esophagus  (d,  d) ; 
but  the  fibres  of  this  part  rise  principally  from 
the  posterior  part  of  the  cephalic  cartilage. 

The  septum  of  the  branchial  chamber  above- 
mentioned  is  the  strongest  and  most  complete 
in  the  genus  Eledone,  where,  with  the  excep- 
tion of  a  very  small  part  of  its  posterior  termi- 
nation, it  is  muscular  throughout.*  In  the 
Poulp,  in  which  this  septum  (c,  Jig.  216)  is 
well  described  by  Cuvier  as  the  "  bride  ante- 
rieure  qui  lie  la  bourse  a  la  masse  viscerale," 
a  greater  proportion  of  the  posterior  part  is 
membranous.  In  the  Argonauta  the  muscular 
part  of  the  septum  is  reduced  to  two  narrow 
and  delicate  fasciculi,  which  arise  from  the 
back  part  of  the  cranial  cartilage,  descend  ob- 
liquely forwards,  intercept  the  termination  of 
the  rectum  and  ink-duct,  to  which  they  serve 
as  a  sphincter,  and  then  expand  in  the  vertical 
direction  to  be  inserted  along  the  middle  line 
of  the  inner  surface  of  the  anterior  part  of  the 
mantle.  A  membrane  is  continued  from  the 
upper  margin  of  the  muscular  septum  to  within 

*  See  Cams'  original  figure,  Vergleich.  Zooto- 
mie,  pi.  iv.  fig.  4,  g,  in  Octopus  (  Eledona)  Mos- 
chatus. 


a  short  distance  of  the  anterior  margin  of  the 
mantle,  and  another  from  the  lower  margin  ex- 
tends downwards,  and  terminates  opposite  the 
base  of  the  gills ;  the  branchial  chambers  in- 
tercommunicate both  above  and  below  this 
septum.  In  Sepiola  the  muscles  corresponding 
to  the  "  bride  anterieure"  of  the  Octopus  are 
developed  in  the  same  degree  as  in  the  Argo- 
naut, arising  not  from  the  back  of  the  funnel, 
but  from  the  cranial  cartilage ;  the  septum  is 
completed  below  by  membrane.  In  the  Cuttle- 
fishes and  Calamaries  these  muscles  and  the 
septum  of  the  branchial  chamber  are  wanting. 

The  muscular  parietes  of  the  funnel  are 
formed  by  an  external  longitudinal  ( e)  and  an 
internal  transverse  (f)  layer,  strengthened  by  the 
insertion  of  the  extrinsic  muscles  of  this  part. 
The  principal  of  these  are  the  lateral  muscles 
(g,  Jig.  216,)  which  in  the  Poulp  take  their 
origin  from  the  capsules  of  two  small  styles, 
hereafter  to  be  described,  at  the  sides  of  the 
mantle,  and  are  inserted  into  the  sides  of  the 
funnel  and  the  muscular  tunic  of  the  liver.  In 
the  Cuttle-fishes  and  Calamaries  they  are  at- 
tached to  the  cartilaginous  articular  cavity  at 
the  sides  of  the  base  of  the  funnel,  as  well  as 
to  its  fleshy  parietes. 

These  muscles  serve  to  retract  and  depress 
the  funnel;  it  is  raised  and  drawn  forwards  by 
two  pair  of  muscles  (h)  which  descend  from 
the  under  and  lateral  parts  of  the  head  to  be 
inserted  into  its  back  part.  But  neither  of 
these  muscles  pass  through  a  sheath,  as  do  the 
corresponding  muscles  in  the  Nautilus. 

A  pair  of  muscles,  whose  important  charac- 
ter is  only  perceived  by  tracing  them  through 
their  successive  stages  of  development  to  the 
Nautilus,  are  those  small  fasciculi  which  Cuvier 
terms  "  la  bride  laterale  qui  joint  la  bourse  a 
la  masse  viscerale."  (i.)  They  arise  in  con- 
junction with  the  fibres  of  the  fleshy  tunic  of 
the  liver,  but  soon  quitting  these,  extend,  as 
distinct  fasciculi,  downwards  and  outwards, 
being  perforated  in  their  course  by  the  great 
lateral  nerve,  and  are  inserted  into  the  upper 
part  of  the  capsule  of  the  rudimental  shell, 
which  the  styles  above-mentioned  represent. 
In  the  Sepia  they  are  proportionally  larger, 
corresponding  to  the  greater  development  of 
the  shell.  They  are  not  inserted,  in  the  Octo- 
pus, into  the  cartilaginous  substance  of  the  in- 
closed style ;  nor,  in  the  Sepia,  into  the  calca- 
reous substance  of  the  cuttle-bone;  neither 
are  they  attached  to  the  calcareous  matter  of 
the  shell  in  the  Nautilus,  where  they  acquire 
their  maximum  of  development.  They  termi- 
nate in  this,  as  in  the  preceding  genera,  in  the 
epidermic  capsule  of  the  shell,  which  has  a 
much  closer  and  more  intimate  adhesion  to 
the  testaceous  substance  in  the  Nautilus  than 
to  the  internal  rudiment  of  the  same  part  in  the 
naked  Cephalopods. 

It  is  well  known  that  zoologists  are  divided 
in  opinion  as  to  whether  the  shell  called  Argo- 
nauta is  formed  by  the  cephalopod  which  in- 
habits it  or  not.  Having  traced  out  the  mus- 
cles in  the  naked  Cephalopods  which  are  ana- 
logous to  those  of  the  shell  in  the  Nautilus,  we 
next  examined  the  Oci/thoe,  with  the  view  of 


CEPHALOPODA. 


531 


ascertaining  if  these  muscles  presented  a  corre- 
sponding degree  of  development,  but  found 
them  proportionally  smaller  even  than  in  the 
naked  Octopus.  All  trace  of  internal  shell  has 
disappeared  in  the  Ocythoc ;  yet  there  is  no 
muscular  connexion  between  the  body  and  the 
external  shell  which  contains  it. 

The  fleshy  fibres  of  the  mantle  being  white 
like  the  rest  of  the  muscles,  and  very  compact, 
are  extremely  difficult  to  follow  in  dissection. 
Cuvier*  observes,  that  in  the  Octopus  those 
which  are  external  are  evidently  longitudinal ; 
those  which  are  internal,  transverse ;  and  that 
there  are  short  fibres  which  pass  through  their 
thickness  from  one  surface  to  another. 

In  the  Cuttle-fish  the  muscular  fibres  of  the 
posterior  part  of  the  mantle  recede  laterally  to 
leave  a  large  space  for  the  lodgement  of  the 
sepium  or  cuttle-bone,  which  is  covered  exter- 
nally by  a  thin  and  flaccid  skin  :  the  rest  of  the 
mantle  is  formed  by  a  thick  muscular  tissue,  as 
in  the  Poulp.  The  lateral  fins  are  connected 
not  only  by  the  skin,  cellular  tissue,  and  vessels, 
as  Cuvier  describes,  but  by  a  distinct  though 
thin  stratum  of  muscular  fibres;  these  arise 
from  the  lateral  and  dorsal  aspects  of  the  apo- 
neurotic  capsule  of  the  rudimental  shell,  and 
are  inserted  into  the  spinal  ridge  of  the  alar 
cartilage  (h,  h,  fg.  212);  from  this  ridge  pro- 
ceed the  fibro-cartilaginous  laminae  and  inter- 
mediate muscles,  which  are  disposed  perpen- 
dicularly to  the  ridge,  and  extend  to  the  mar- 
gins of  the  fin. 

In  the  Calamaries  the  muscles  which  con- 
nect the  terminal  fins  to  the  body  are  still 
more  distinct.  By  means  of  these  fins  they 
are  enabled  to  propel  themselves  forward  in 
the  sea ;  and  there  is  good  reason  for  believing 
that  some  of  the  small  slender-bodied  subu- 
late species  of  this  genus  are  enabled  to  strike 
the  water  with  such  force  as  to  raise  them- 
selves above  the  surface,  and  dart,  like  the 
flying  fish,  for  a  short  distance  through  the 
air.f 

DIGESTIVE  SYSTEM. — The  animals  which  we 
have  thus  seen  to  be  endowed  with  so  various 
and  formidable  means  for  seizing  and  over- 
coming the  struggles  of  a  living  prey  are  pro- 
vided with  adequate  weapons  for  completing 
its  destruction,  and  preparing  it  for  deglutition. 
These  consist  of  a  pair  of  strong,  sharp,  hooked 
mandibles,  which  are  of  a  horny  texture  in  the 
Dibranchiate  Cephalopod,  (a,  6,  Jig.  218,) 
where  they  are  fitted  for  cutting  and  tearing  the 
softer  animals  which  they  are  enabled  to  catch ; 
but  are  strengthened  by  a  dense  calcareous  sub- 
stance in  the  Nautilus,  (a,  6,  Jig.  217,)  which, 
from  its  more  limited  sphere  of  action,  is  pro- 

*  Menaoire  sur  le  Poulpe,  p.  11. 

t  See  Proceedings  of  the  Zool.  Society,  Pt.  i, 
1833,  p.  90.  The  faculty  possessed  by  the  Cala- 
marics  of  darting  thiough  the  atmosphere  was  not 
unknown  to  the  ancients.  Pliny  (Hist.  Nat.  lib. 
ix.  torn.  ii.  p.  105,  Cuvier's  Ed.)  says,  "  Loligo 
etiam  volitat,  extra  aquam  se  efferens,  quod  et 
pectunculi  faciunt  sagittae  modo  ;"  and  so  general 
appears  to  have  been  this  belief  that  Varro  sup- 
posed the  name  Loligo  to  be  a  corruption  of  Voligo. 
"  Loligo  dicta,  quod  subvolat,  littera  commulata, 
primo  Voliyo."—De  Ling.  Lut.  lib.  iv.  p.  21. 


bably  restricted  in  regard  to  food  to  such  crus- 
taceous  and  testaceous  animals  as  it  may  sur- 
prise by  stealth,  and  whose  defensive  armour  it 
is  thus  enabled  to  break  up.* 

The  mandibles,  which  are  hollow  sheaths, 
like  the  horny  covering  of  the  beak  of  a  Bird 
or  Tortoise,  are  fixed  upon  a  firm  fleshy  sub- 
stance, (c,  c,  Jig.  217,)  which  resembles  the 


Fig.  217. 


Mandibles  of  the  Navtiliu. 

animal  part  of  bone  after  the  earth  has  been 
removed  by  means  of  an  acid.  At  the  base  of 
the  mandibles  the  fibrous  structure  of  this  part 
becomes  apparent,  and  a  strong  stratum, 
(g,  Jig.  217,)  passing  between  the  bases  of  the 
mandibles,  serves  for  their  divarication ;  their 
closure  is  effected  by  fasciculi  of  muscular 
fibres,  which  surround  them  externally  near 
the  reflection  of  the  circular  lip.  When  the 
mouth  is  closed,  the  lower  mandible  (6)  over- 
laps the  upper  (a). 

The  oral  aperture  is  in  the  centre  of  the 
base  of  the  feet,  and  appears  in  the  form  of  a 
small  circular  orifice,  formed  by  the  contracted 
fleshy  lip  wjiich  surrounds  and  more  or  less 
conceals  the  mandibles. 

In  the  Nautilus  the  margin  of  the  lip  (c)  is 
beset  with  several  rows  of  elongated  papillae, 
irregularly  disposed  ;  external  to  which  are 
the  labial  processes  with  their  tentacles  : 
these,  in  the  specimen  we  dissected,  com- 
pletely overlapped  and  concealed  the  oral  ap- 
paratus. 

In  the  Calamaries  the  jaws  are  surrounded, 
external  to  the  fringed  circular  lip,  by  a  thin 
membrane,  which  is  produced  into  short  pyra- 
midal processes,  corresponding  in  number  to 
the  eight  feet,  and  supporting  minute  rudimen- 
tal suckers  ;  thus  imitating  the  external  feet, 
as  the  labial  processes  of  the  Nautilus  repeat 
the  structure  of  the  digital  processes.  In  the 
genus  Sepioteuthis  the  circular  lip  immediately 
surrounding  the  jaws  is  tumid  and  plicated, 
but  not  papillose ;  external  to  it  are  two  cir- 
cular ridges  of  membrane,  then  a  thin  mem- 
brane with  jagged  margins,  and  lastly  a  mem- 
brane with  its  margin  produced  into  eight 
angular  processes,  which  are  not,  however, 
free,  as  in  Loligo,  but  are  tied  down  in  the 
interspaces  of  the  eight  legs ;  small  rudimental 
suckers  may  be  observed  on  these  processes. 

*  The  digestive  canal  of  the  Nautilus  was  found 
filled  exclusively  with  the  remains  of  a  species  of 
crab. 


532 


CEPHALOPODA. 


In  Onychoteuthis  the  inner  lip  (d,  fg.  218)  is 
tumid,  and  merely  subplicated ;  the  angles  of 
the  external  labial  membrane    are    extended 
along  the  middle  of  each  foot  for  a  short  dis- 
tance.    In  Sepia  the  inner  lip  is  fringed,  as  in 
Nautilus.    The  outer  lip  is  tied  down  by  mus- 
cular bands  to  the  bases  of  the  arms,  but  sends 
forward  eight  short,  conical,  unarmed  processes. 
In  Loligopsis  and  Cranchia  the  outer-lip  sends 
off  a  muscular  band  to  the  base  of  each  arm, 
but  has  no   free  processes.     In  Octopus  the 
suckers  commence  immediately  round  the  mar- 
gin  of  the   oral  aperture,   which  is   so  con- 
tracted that  the  mandibles  can  seldom  be  seen 
without     dissection :     the 
inner-lip  is  fimbriated,  as  in 
Sepia.      In   Ocythoe  it  is 
tumid  and  entire,  but  pli- 
cated both    circularly  and 
transversely. 

The  tongue  is  a  large  and 
complicated  organ,  and  is 
constructed  on  the  same 
plan  in  both  orders  of 
Cephalopods.  In  the  Nau- 
tilus it  is  supported  by  an 
oblong  horny  transversely 
striated  substance,  which 
appears  to  represent  the 
body  of  an  os  hyoides  (a, 
fg.  236.)  The  posterior  ex- 
tremity of  this  substance  is 
free,  or  connected  only  by  a  few  filaments  with 
the  parts  above,  but  its  anterior  extremity  is 
embraced  by  a  pair  of  retractor  muscles  (6), 
which  originate  from  the  posterior  margins  of 
the  lower  mandible.  The  fleshy  substance  of 
the  tongue,  thus  supported,  is  produced  ante- 
riorly, and  forms  three  caruncles  (c),  very  soft 
in  texture,  and  beset  with  numerous  papillae, 
having  all  the  characters  of  a  perfect  organ  of 
taste.  The  anterior  or  terminal  caruncle  is  the 
largest,  and  four  delicate  retractor  or  depressor 
muscles  (d)  are  inserted  into  it.  Behind  the 
caruncles  the  dorsum  of  the  tongue  is  encased 
with  a  thin  layer  of  horny  matter,  about  five 
lines  in  length,  from  which  arise  four  longitu- 
dinal rows  of  slender  prickles  (e),  which  are 
from  one  to  two  lines  in  length,  and  are  in- 
curvated  backwards.  The  number  of  these 
prickles  is  twelve  in  each  row,  singularly  cor- 
responding with  the  number  of  tentacles  given 
off  from  the  labial  processes. 

It  is  unnecessary  to  allude  to  the  obvious 
utility  of  this  structure  in  seizing  the  morsels 
of  food,  and  directing  them  towards  the  gullet, 
after  they  have  been  broken  up  by  the  mandi- 
bles. Behind  this  horny  part  the  tongue  again 
becomes  soft  and  papillose  (j\  but  the  papillae 
are  coarser  and  larger  than  those  on  the  anterior 
portions.  Two  broad  fleshy  processes  (g,  g,) 
project  forwards  from  the  sides  of  the  fauces  : 
these  also  are  papillose,  and  are  perforated  in 
the  middle  of  their  inner  surfaces  by  a  small 
aperture  (h,  A),  which  leads  into  a  glandular 
cavity,  situated  between  the  folds  of  the  mem- 
brane, and  analogous  to  the  superior  pair  of 
salivary  glands  in  the  Poulp,  Calamaries,  &c. 

In  the  Dibranchiate  Cephalopods  the  tongue 


Fig.  218. 


Section  of  the  Beak,  with  the  Tongue  of  CM  Onychoteuthis. 


is  similarly  composed  of  an  anterior  and  pos- 
terior papillose  and  a  middle  spiny  portion. 
In  the  specimen  from  which  the  figure  (218) 
was  taken,  the  anterior  fleshy  portion  (e) 
was  slightly  divided  into  three  parts,  but  was 
retracted  by  a  single  round  muscle,  and  the 
papillae  were  relatively  fewer  and  coarser  than 
in  the  Nautilus  :  at  its  sides  there  were  several 
orifices  of  glandular  follicles.  The  horny  plate, 
covering  the  middle  part  of  the  tongue,  is  bent 
at  right  angles;  the  recurved  hooks  in  the 
Onychoteuthis  are  confined  to  the  anterior  and 
vertical  surface ;  they  commence  above  or  be- 
hind in  seven  rows ;  but,  as  they  descend,  first 
the  two  outer  on  each  side  blend  together,  and 
then  each  united  row  joins  the  next,  so  that 
there  remain  but  three  rows  at  the  lower  part 
of  the  sheath.  In  the  Cuttle-fish  the  seven 
rows  of  lingual  spines  continue  distinct. 

In  the  Onychoteuthis  the  posterior  portion 
of  the  tongue  (g)  is  inclosed,  as  in  the  Nau- 
tilus, between  two  faucial  or  pharyngeal  folds 
of  membrane  (A,  A),  but  their  inner  surfaces, 
instead  of  being  merely  papillose,  are  beset 
with  rows  of  small  recurved  spines,  which 
must  greatly  assist  the  act  of  deglutition. 

The  superior  salivary  glands  (t)  are  not  con- 
fined to  the  outside  of  the  buccal  mass,  as  in 
the  Octopus,  but  extend  between  the  layers  of 
membrane  which  form  the  pharyngeal  fold, 
forming  here  a  flattened  mass  («) ;  their  duct 
opens  at  the  bottom  of  a  longitudinal  fissure  on 
the  inner  surface  of  the  fold ;  styles  are  repre- 
sented passing  into  the  ducts  of  these  glands 
in  the  figure. 

In  most  of  the  Dibranchiata  a  second  and 
generally  larger  pair  of  salivary  glands  are 


CEPHALOPODA. 


533 


found  below  the  cartilaginous  cranium,  situ- 
ated in  the  hepatic  cavity,  on  either  side  of 
the  oesophagus.  A  single  excretory  duct  is 
continued  from  each  gland,  and  the  two  unite 
and  form  one,  as  they  are  passing  through  the 
cranium.  The  common  duct  penetrates  the 
lower  or  central  surface  of  the  buccal  mass, 
and  is  continued  along  the  concavity  of  the 
lower  mandible,  through  the  tongue  to  the 
lower  part  of  the  spiny  plate,  where  it  termin- 
ates. In  the  Octopus  these  glands  are  veiy 
large,  and  have  a  smooth  surface  (q,fig-  233) ; 
but  in  many  Cephalopods,  as  in  Ocythoe, 
Sepiola,  and  Rossia,  they  are  relatively  smaller, 
and  have  a  granular  surface.  It  is  in  the  genus 
Loligopsis  alone  that  these  glands  have  hither- 
to been  found  wanting. 

With  respect  to  the  ultimate  structure  of  the 
salivary  glands  of  the  Cephalopoda,  Miiller* 
observes  that  they  are  not  composed  of  solid 
acini  or  granules,  but  of  hollow  canals  or  cells. 

Before  the  description  of  the  abdominal 
viscera  is  proceeded  with,  it  is  necessary  to 
make  a  few  observations  on  their  position  and 
connections. 

In  the  ventricose  and  short-bodied  species 
of  Cephalopoda  the  mantle-sac  is  almost  wholly 
filled  with  the  viscera,  but  in  those  of  an  elon- 
gated form  they  are  more  or  less  confined  to 
the  lower  part  of  the  sac,  and  a  vacant  space 
intervenes  between  the  visceral  mass  and  the 
opening  of  the  mantle,  which  is  traversed  by 
the  respiratory  currents :  the  part  of  the  mantle 
unoccupied  by  the  viscera  is  most  remarkable 
for  its  extent  in  the  genus  Loligopsis  (Jig.  223.) 

If  the  mantle  of  the  common  Octopus  or 
Poulp  be  laid  open  longitudinally,  and  a  little 
to  one  side  of  the  mesial  line,  a  cavity  will  be 
exposed,  separated  by  the  longitudinal  muscular 
septum  (c,fg.  216)  from  the  corresponding  one 
of  the  opposite  side ;  in  these  two  cavities  are 
contained  the  branchiae  (r,jig.  216),  the  termi- 
nations of  the  oviducts  (p),  and  the  pericardial 
apertures  (q).  Below  and  behind  the  branchial 
cavities,  the  peritoneum  is  seen  enveloping  the 
rest  of  the  viscera ;  but  this  great  serous  sac  is 
subdivided  into  many  compartments.  If  the 
point  of  the  scissors  be  inserted  into  the  project- 
ing orifice  internal  to  the  root  of  the  gill  (i,Jig. 
226),  and  the  cavity  of  which  it  is  the  outlet  be 
laid  open,  the  branchial  ventricle,  the  branchial 
division  of  the  vena  cava,  and  its  appended 
follicles  will  be  exposed ;  this  cavity  is  sepa- 
rated from  a  corresponding  one  on  the  opposite 
side  by  the  systemic  heart  and  the  great  vessels, 
which  are  contained  in  a  distinct  serous  com- 
partment. In  the  Nautilus  the  two  lateral  and 
the  middle  cavities  form  one  large  pericardiuc 
chamber,  appropriated  to  the  heart  and  great 
vessels,  and  the  venous  appendages. 

Behind  these  cavities,  the  peritoneum  is 
disposed  so  as  to  form  several  compartments : 
one,  which  commences  at  the  cranial  cartilage, 
extends  downwards  as  far  as  the  middle  of  the 
branchiae,  and  contains  the  oesophagus,  the 
inferior  salivary  glands,  the  crop,  and  anterior 
aorta  :  in  front  of  this,  but  commencing  a  little 

*  De  structura  glandularum  penitiori,  fol.  p.  54. 


lower  dovrn,  is  a  second,  which  includes  the 
liver  and  ink-bag.  These  two  cavities  are  sur- 
rounded by  a  common  muscular  tunic,  of 
which  we  have  already  spoken,  and  the  lower 
part,  which  resembles  a  diaphragm,  is  per- 
forated by  the  gullet,  the  aorta,  and  the  two 
biliary  ducts,  each  of  which  has  a  distinct 
aperture.  The  receptacle  which  contains  the 
gizzard  is  situated  immediattly  beneath  the 
oesophageal  sac ;  that  in  which  the  spiral  py- 
loric  appendage  is  lodged  lies  immediately 
behind  the  left  compartment  of  the  pericar- 
dium. The  intestine  is  principally  contained 
in  a  serous  cavity  behind  the  right  division  of 
the  pericardium ;  and  the  bottom  of  the  sac  is 
occupied  by  the  cavity  containing  the  organs 
of  generation. 

The  digestive  organs  in  the  Tetrabranchiate 
Cephalopods  would  appear  to  differ  in  a  less 
degree  than  other  parts  of  their  organization  from 
the  structures  observable  in  the  higher  order : 
in  the  Nautilus  they  present  the  following  con- 
formation. 

The  pharynx  (ft  Jig.  217)    or  commence- 


Fig.  219. 


Digestive  Organs,  Nautilut  Pompilius. 

ment  of  the  gullet,  has  numerous  longitudinal 
rugae  internally,  and  is  evidently  capable  of  con- 
siderable dilatation.  The  oesophagus,  after 
having  passed  beneath  the  brain,  or  commissure 
of  the  optic  ganglions,  dilate  into  a  capacious 
pouch  or  crop  (k,fg.  219)  of  a  pyriform  shape, 
two  inches  and  three  lines  in  length,  and  an 
inch  in  diameter  at  the  broadest  part.  From 
the  bottom  of  this  crop  is  continued  a  contracted 
canal  (I, fig.  219,)  of  about  three  lines  in  diame- 
ter, and  half  an  inch  in  length,  which  enters  the 


534 


upper  part  of  an  oval  gizzard  (m,  jig.  219) 
situated  at  the  bottom  of  the  palhal  sac. 
Close  to  where  this  tube  enters,  the  intestine 
(w,  jig.  219)  is  continued  from  the  gizzard, 
and  after  a  course  of  a  few  lines  communicates 
with  a  small  round  laminated  pouch  or  ap- 
pendage (>,/g.  219)  analogous  to  the  spiral 
coecum  of  the  Cuttlefish,  into  which  the  biliary 
secretion  is  poured :  from  thence  the  intestine 
is  continued,  twice  bent  upon  itself,  but  with- 
out varying  materially  in  its  dimensions,  to  its 
termination  (o,  Jig.  219).  In  this  course  it 
first  ascends  for  about  an  inch  and  a  half, 
then  makes  a  sudden  bend  down  to  the  bottom 
of  the  sac,  and  returns  as  suddenly  upon  itself, 
passing  close  to  the  pericardium,  and  terminat- 
ing between  the  roots  of  the  bronchia?. 

The  alimentary  canal  is  every  where  con- 
nected to  the  parietes  of  the  abdomen  by 
numerous  filaments ;  the  only  trace  of  a  me- 
sentery exists  between  the  two  last  portions 
of  the  intestine,  which  are  connected  together 
by  membranes  including  the  ramifications  of 
an  artery  and  vein.* 

The  longitudinal  rugse,  into  which  the 
lining  membrane  of  the  cesophagus  is 
thrown,  disappear  at  its  entrance  into  the 
crop.  The  muscular  coat  of  the  crop  con- 
sists of  an  exterior  layer  of  close-set  circu- 
lar fibres  and  an  inner  layer  of  more 
scattered  longitudinal  ones.  The  lining 
membrane  is  thin  but  tough,  with  a 
smooth  surface  :  when  the  cavity  is  empty, 
it  is  probably  thrown  into  longitudinal 
folds  by  the  action  of  the  circular  fibres. 

In  the  canal  which  leads  to  the  gizzard, 
the  lining  membrane  puts  on  a  villous 
appearance  and  is  disposed  in  distinct 
close-set  longitudinal  rugae. 

The  gizzard  is  girt  by  two  broad  radiate 


CEPHALOPODA. 


muscles,  of  the  thickness  of  two  lines,  arising 
from  opposite  tendons  :  it  is  lined  by  a  thick 
cuticular  membrane,  delicately  furrowed  and 
adapted  to  numerous  fine  ridges  which  tra- 
verse longitudinally  the  whole  interior  of  the 
cavity.  This,  as  is  commonly  found  in  gizzards, 
was  detached  from  part  of  the  parietes  and 
adhered  very  slightly  to  the  remainder. 

The  pyloric  orifice  is  close  to  the  cardiac, 
and  is  guarded  by  a  valve,  to  prevent  a  too 
ready  egress  of  matter  from  the  gizzard.* 

The  globular  cavity  (p,  Jig.  219)  which 
communicates  with  the  intestine  at  a  little  dis- 
tance from  the  pylorus,  is  occupied  with  broad 
parallel  laminae,  which  are  puckered  trans- 
versely, so  as  to  increase  their  surface  for  vas- 
cular ramifications;  their  texture  under  the 
lens  is  follicular  and  evidently  fitted  to  secrete. 
The  bile  enters  this  cavity  at  the  extremity 
furthest  from  the  intestine  by  a  duct  large 
enough  to  admit  a  common  probe.  The  two 
laminae  on  each  side  the  entrance  of  the  duct 
increase  in  breadth  as  they  approach  the  in- 
testine, and  are  continued  in  a  curved  form 


i.  220. 


Alimentary  Canal  of  the 


*  fn  the  specimen  of  the  Nautilus  from  which 
the  preceding  account  is  derived,  the  whole  alimen- 
tary canal  was  filled  with  fragments  of  some  species 
of  crab,  among  which  portions  of  branchiae,  claws, 
and  palpi,  were  distinctly  recognizable.  The  crop 
in  particular  was  tensely  filled  with  these  substances, 
and  the  capability  of  propelling  such  rude  and 
angular  particles  through  a  narrow  canal  in  the 
gizzard,  without  injury  to  the  thin  tunics  of  the 


preparatory  cavity,  is  a  remarkable  example  of  the 
superior  powers  of  living  over  dead  matter. 

*  The  contents  of  this  part  of  the  alimentary 
canal  were  in  smaller  pieces  than  in  the  crop, 
but  of  the  same  nature  ;  the  fragments  of  shell  were 
comminuted  apparently  by  mutual  attrition,  as  there 
were  no  particles  of  sand  or  pebbles  present. 

f  From  Ferussac's  Monograph  on  the  Cephalopoda 
Acetabuliferes. 


CEPHALOPODA. 


535 


along  that  canal,  being  gradually  lost  in  its 
inner  membrane,  the  lamina  next  the  gizzard 
is  peculiarly  enlarged,  so  as  evidently  to  pre- 
sent an  obstacle  to  the  regurgitatio'n  of  bile 
towards  the  gizzard.  The  inner  surface  of  the 
rest  of  the  intestinal  canal  presents  a  few  lon- 
gitudinal rugae,  with  slightly  marked  transverse 
puckerings. 

In  the  Dibranchiate  Cephalopods  the  gul- 
let, in  consequence  of  the  position  of  the 
stomach  near  the  lower  part  of  the  visceral 
sac,  is  of  great  length  (a,  a,  Jig.  221),  but 
varies  in  this  respect  according  to  the  form 
of  the  animal.  We  have  seen  that  in  the 
Nautilus  it  is  dilated  into  a  pyriform  crop; 
a  similar  dilatation  occurs  in  the  genus  Octo- 
pus ;  but  its  position  is  reversed,  the  larger  end 
of  the  sac  being  uppermost,  and  probably  as 
the  result  of  the  habitually  reversed  position  of 
the  animal  with  the  head  downwards,  the  crop 
is  extended  into  a  large  cul-de-sac  above  the 
part  where  the  oesophagus  opens  into  it  (b, 
Jig.  220).  From  this  part  the  crop  gradually 
contracts  to  its  termination. 

In  the  Argonaut  the  crop  commences  by  a 
similar  lateral  dilatation,  but  is  continued  of 
almost  uniform  breadth  to  the  stomach. 

In  the  Sepia,  Sepiola,  Rossia,  Onychoteuthis, 
Loligopsis,  and  Loligo,  and  probably  in  the 
other  Decapods,  there  is  no  crop,  the  gullet 
being  continued  of  uniform  breadth  to  the 
stomach  (a,  a,  jig.  221).* 

The  stomach  (c,  Jigs.  220,  221,)  in  all  the 
Dibranchiate  Cephalopods  is  a  more  or  less 
elongated  sac,  having  its  two  orifices,  the  car- 
dia  (d)  and  pylorus  (e),  close  together  at  the 
anterior  or  upper  part  of  the  sac,  as  in  the 
gizzard  of  birds :  the  muscular  fibres  are  simi- 
larly disposed,  and  radiate  from  two  opposite 
tendons;  they  form  a  stratum  of  about  the 
same  thickness  as  in  the  stomachs  of  omnivo- 
rous birds.  The  epithelium,  which  is  con- 
tinued from  the  oesophagus  and  crop  (a',  &', 
fig.  220)  acquires  a  greater  thickness  in  the 
gizzard,  and  is  disposed  in  longitudinal  rugae ; 
it  is  readily  detached  from  the  muscular  tunic. 

The  intestine,  at  a  short  distance  from  the 
pylorus,  communicates  with  a  glandular  and 
laminated  sac,  analogous  to  the  pyloric  ap- 
pendages in  Fish,  but  which  in  the  Cephalo- 
pods is  always  single. 

In  the  Nautilus,  we  have  shewn  that  this 
rudimental  pancreas  (p,  fig.  219)  is  of  a  sim- 
ple globular  form,  as  in  the  Doris  and  some 
other  Gasteropoda.  It  presents  a  similar  form 
in  Rossia  and  Loligopsis,  in  the  latter  of  which 
it  is  of  large  size  (g,  fig.  223).  In  Argo- 
nauta  it  is  triangular;  in  some  species  of 

"  From  this  difference  I  conclude  that  Aristotle 
took  his  description  of  the  digestive  viscera  of  the 
Malakia  from  the  Septa  or  Teuthis:  he  says,  Mtra, 
8i  TO  0-rsfj.et  txpvrn  o'<ro<J>ayov  juaxpoy  xa»  e'Ttvov, 
i^o'/uivov  Ji  Touroy  flrpc'Xo#9V  /ulyav  *«<  <f>epjflp? 
opvt0(iJ>j.  "  After  the  mouth  they  have  a  long  and 
narrow  cesophagus,  then  a  large  round  gizzard 
similar  to  that  of  a  bird." — Hist,  de  Anim.  lib.  iv. 
c.  1.9.  But  it  is  evident  that  he  also  had  dissected 
the  Octopus,  as  he  afterwards  notices  the  difference 
in  the  position  of  the  ink-bag,  which  occurs  in  this 
genus  as  compared  with  the  Sepia, 


Loligo,  as  in  the  Loligo  communis,  it  is  ex- 
tended into  a  long  pyriform  membranous  bag, 
but  in  the  Loligo  sagittata,  Sepia,  and  Octopus, 
it  is  elongated  and  twisted  spirally,  whence 
it  is  compared  by  Aristotle  to  the  shell  of  a 
Whelk  (f,  figs.  220,  221).  In  each  of  these 


JFVg.221. 


Alimentary  canal  of  the  Sagittated  Calamary.* 

genera  its  cavity  is  occupied  by  glandular 
laminae  (g,  g) ;  the  biliary  ducts  terminate  be- 
tween two  of  the  largest  folds,  which  make  a 
curve  as  they  pass  into  the  intestine,  and  are 
continued,  gradually  diminishing  in  size,  along 
the  canal,  presenting  at  its  commencement  two 
tumid  projections,  which  tend  to  prevent  a 
regurgitation  of  bile  towards  the  pylorus. 

The  intestine  in  the  Nautilus  makes  a 
loop,  or  narrow  fold  upon  itself  before 
it  is  continued  forwards  to  the  base  of  the 
funnel.  In  the  Octopus  it  is  characterized  by 
a  similar  fold,  but  in  the  Cuttle-fish  and  Cala- 
mary the  gut  is  continued  in  a  straight  line  from 
the  stomach  to  the  vent  (i,  i,  fig.  221),  and  is 
consequently  very  short  and  simple :  in  both 
cases  it  maintains  nearly  a  uniform  diameter 
to  its  termination. 

The  internal  tunic  of  the  intestine  is  dis- 
posed in  longitudinal  folds,  of  which  the  two 
at  its  commencement,  above  described  (i,  i, 
fig.  220),  are  the  most  conspicuous.  The  lon- 
gitudinal rugae  in  the  Sepioteuthis  and  Cala- 

*  Home,  Lectures  on  Comp.  Anat.  pi.  Ixxxiii. 


536 


CEPHALOPODA. 


Fig.  222. 


mary  terminate  abruptly  where  the  duct  of 
the  ink-bag  enters  the  gut  (/c,  fig.  221),  which 
for  the  small  extent  beyond  this  part  is  smooth 
internally. 

In  the  Octopods  the  intestine  passes  through 
the  muscular  septum  of  the  branchial  cham- 
ber, immediately  above  which  it  terminates. 
In  the  Decapods  the  rectum  and  duct  of  the 
ink-gland  are  surrounded  by  the  muscular  fibres 
which  connect  the  pillars  of  the  funnel  to  one 
another;  in  both  cases  the  fibres  serve  as  a 
sphincter  to  the  anus. 

In  many  Dibran- 
chiata,  especially  the 
Decapods,  the  termi- 
nation of  the  rectum 
is  provided  with  two 
lateral  fleshy  appen- 
dages ;  for  which,  as 
far  as  we  know,  no  use 
has  hitherto  been  as- 
signed. In  the  Sepio- 
teuthis  these  process- 
es (a,  a,  fg.  222)  are 
of  a  broad  inequilate- 
ral triangular  form,  Anal  valves,  Sepioteuthu. 
attached  to  the  sides 

of  the  transverse  anal  aperture  (6)  by  their 
acute  angle,  from  which  a  ridge  extended  lon- 
gitudinally to  the  middle  of  the  base ;  when 
the  processes  were  folded  down  upon  the  vent 
(as  in  .4,^. 222),  the  ridge  fitted  into  the  aper- 
ture, so  as  accurately  to  close  it.  In  the 
Cuttle-fish  the  corresponding  processes  are  of  a 
rhomboidal  form,  with  a  thicker  ridge  on  the  side 
next  the  anal  aperture,  which  they  in  like  man- 
ner are  adapted  to  defend  against  the  entrance 
of  foreign  substances  by  the  funnel.  In  other 
genera  they  are  not  adapted  to  defend  the  anus 
mechanically,  being  elongated  and  filiform; 
but  they  probably  serve  to  give  warning 
of  the  presence  of  foreign  bodies,  and  excite 
the  necessary  contraction  of  the  constrictors 
of  the  gut ;  Rathke"  compares  them  to  antennae 
in  the  Loligopsis,  where  the  anal  processes  are 
very  long  (11,  fig.  223). 

The  apparatus  for  secreting  the  inky  fluid, 
formerly  regarded  as  characteristic  of  the  class 
of  Cephalopods,  is  wanting  in  the  Nautilus, 
which,  as  it  has  a  large  and  strong  shell  to  pro- 
tect its  body,  stands  less  in  need  of  such  a 
means  of  defence :  the  ink-bag  is,  however, 
present  in  the  Argonauta. 

The  ink-bag  (/,  fig.  221)  varies  in  its  re- 
lative position  in  different  Dibranchiata:  in 
the  Cuttle-fish  it  is  situated  near  the  bottom 
of  the  pallial  sac,  in  front  of  the  testicle  or 
ovary.  In  the  Calamary  it  is  raised  close  to 
the  termination  of  the  intestine;  we  have  found 
it  similarly  situated  in  the  Argonauta,  Sepioteu- 
this,  and  Ilossia.  In  the  Octopus  it  is  buried 
in  the  substance  of  the  liver,  a  small  part  only 
of  its  parietes  appearing  on  the  anterior  sur- 
face of  that  gland,  from  which  its  duct  is  con- 
tinued forwards  to  terminate  in  this  genus  im- 
mediately behind  the  anus. 

From  this  connection  of  the  ink-bag  with 
the  liver  in  the  Poulp,  Monro  was  led  to  sus- 
pect it  to  be  the  gall-bladder.  What  its  real 


nature  may  be  still  remains  doubtful ;  De  Blain- 
ville  and  Jacobson  regard  it  as  a  rudimental 
urinary  apparatus  :*  Sir  Everard  Home  f  com- 
pares it  to  the  secreting  sac  which  opens  into 
the  rectum  in  Rays  and  Sharks,  and  this  we 
consider  to  be  the  true  homology  of  the  ink- 
bag.  It  is  interesting,  indeed,  to  observe  that 
corresponding  anal  glandular  cavities  in  the 
Mammalia  are  in  many  instances  modified  to 
serve  by  the  odour  of  their  secretion  as  a  means 
of  defence,  just  as  the  part  in  question  operates 
in  the  Cephalopods  by  reason  of  the  colour  of 
the  ejected  fluid. 

When  the  ink-bag  is  laid  open  and  well 
cleansed  of  its  contents,  its  inner  surface  is 
seen  to  be  composed  of  a  fine  cellular  or 
spongy  glandular  substance :  its  exterior  coat 
is  of  a  tough  white  fibrous  texture,  and  its 
outer  surface  commonly  exhibits  a  peculiar 
glistening  or  silvery  character. 

The  ink-bag  probably  attains  its  largest  pro- 
portional size  in  the  genus  Sepiola,  where  it 
presents  a  trilobate  form.  It  is  of  an  oblong 
pyriform  shape  in  Sepia,  Sepioteuthis,  and 
Loligo.  It  is  relatively  larger  in  Sepia  than 
in  Octopus,  and  the  quantity  of  water  which 
its  contents  will  discolour  is  very  surprising: 
it  behoves  the  anatomist,  therefore,  to  be  very 
careful  not  to  puncture  this  part  during  the 
dissection  of  a  Cephalopod. 

In  the  living  Cephalopods  the  inky  fluid  is 
secreted  with  amazing  rapidity ;  we  have  seen 
an  Octopus,  which  had  previously  discoloured 
the  water  for  a  considerable  extent  around  it, 
immediately  after  its  capture  continuing  its 
black  ejections  several  times  in  quick  succes- 
sion, and  ultimately  expelling  in  convulsive  jets 
a  colourless  fluid,  when  the  powers  of  secreting 
the  black  pigment  were  exhausted. 

In  every  species  of  Cephalopod  which  pos- 
sesses this  organ,  the  tint  of  the  secretion  cor- 
responds, more  or  less,  with  the  coloured  spots 
on  the  integument.  The  Italian  pigment, 
called  (  Sepia/  and  the  Chinese  one,  com- 
monly called  '  Indian  Ink,'  both  of  which  are 
the  inspissated  contents  of  the  organ  above 
described,  afford  examples  of  different  shades 
of  this  singular  secretion. 

If  the  Cephalopods  are  enabled  thus  to  con- 
ceal themselves  during  the  day,  they  have  also 
the  power,  by  means  of  another  secretion,  to 
render  themselves  conspicuous  by  night  by 
means  of  a  phosphorescent  exhalation.^ 

The  Liver. — This  gland  is  remarkable  in  the 
Cephalopods,  as  in  the  other  classes  of  the  Mol- 
luscous Sub-kingdom,  for  its  great  proportional 
size.  In  the  Nautilus  the  liver  (q,  q,  Jig.  219) 
extends,  on  each  side  of  the  crop,  from 
the  oesophagus  to  the  gizzard.  There  is  a 
parallelism  of  form,  as  will  be  afterwards  seen, 
between  this  gland  and  the  Respiratory  organs, 

*  Davy  states  that  the  secreted  fluid  is  "  a  car- 
bonaceous substance  mixed  with  gelatine  j"  but, 
according  to  Bizio,  this  secretion  yields  on  analysis 
a  substance  .ini  generis,  which  he  calls  '  Melauia.' 
See  Edinb.  Phitos.  Journal,  vol.  xiv.  p.  376. 

f  Lectures  on  Comp.  Anat.  vol.  i.  p.  398. 

|  See  Oligerus  Jacobaeus  de  Sepiaeluce,  in  the 
Acta  Hafniens.  vol.  v.  p.  283. 


CEPHALOPODA. 


537 


for  it  is  divided  into  four  lobes,  and  these  are 
connected  by  a  fifth  portion,  which  passes 
transversely  below  the  fundus  of  the  crop. 
All  these  larger  divisions  are  subdivided  into 
numerous  lobules  of  an  angular  form,  which 
vary  in  size  from  three  to  rive  lines.  These 
lobules  are  immediately  invested  by  a  very 
delicate  capsule,  and  are  more  loosely  sur- 
rounded by  a  peritoneal  covering  common  to 
this  gland  and  the  crop. 

The  liver  is  supplied  by  large  branches 
which  are  given  off  from  the  aorta,  (r,fig.  219,) 
as  that  artery  winds  round  the  bottom  of  the 
sac  to  gain  the  dorsal  aspect  of  the  crop.  It  is 
from  the  arterial  blood  alone,  in  this,  as  in 
other  Mollusks,  that  the  secretion  of  the  bile 
takes  place,  there  being  but  one  system  of 
veins  in  the  liver,  corresponding  to  the  hepatic, 
which  returns  the  blood  from  that  viscus,  and 
conveys  it  to  the  vena  cava  at  its  termination. 
The  colour  of  the  liver  is  a  dull  red  with  a 
violet  shade ;  its  texture  is  pulpy  and  yielding. 
When  the  capsule  is  removed  by  the  forceps, 
the  surface  appears  under  the  lens  to  be  mi- 
nutely granular  or  acinous,  and  these  acini 
are  readily  separable  by  the  needle  into  clusters 
hanging  from  branches  of  the  bloodvessels  and 
duct.  The  branches  of  the  duct  arising  from 
the  terminal  groupes  of  the  acini,  form,  by 
repeated  anastomoses,  two  main  trunks,  which 
unite  into  one  at  a  distance  of  about  two  lines 
from  the  laminated  or  pancreatic  cavity. 

There  appears  to  be  one  example  in  the 
Dibranchiate  Order  where  the  liver  is  divided 
into  four  lobes,  as  in  the  Nautilus ;  this  occurs, 
according  to  Dr.  Grant,  in  the  Loligopsis 
guttata  ;  but  in  the  figure  which  is  given  of 
this  structure  the  lobes  are  each  distinct 
from  the  rest,  and  divided  at  the  middle 
line ;  while  in  the  Nautilus  the  four  lobes  are 
united  together.  Itathke",  on  the  contrary, 
who  has  given  an  elaborate  account  of  the 
Anatomy  of  Loligopsis  under  the  name  of 
Perothis*  describes  and  delineates  the  liver, 
in  the  two  species  of  that  genus  dissected  by 
him,  as  a  simple  undivided  viscus,  of  an  ellip- 
soid figure,  situated  in  the  middle  line  of  the 
body  (12,  Jig.  223).  In  Onychoteuthis  Banksii 
the  liver  is  a  single  elongated  laterally  com- 
pressed lobe,  obtuse  and  undivided  at  both 
extremities.  In  the  Sagittated  Calamary  it  is 
single,  elongated,  and  cylindrical.  In  Sepia 
and  Rossia  it  is  divided  into  two  lateral  lobes, 
both  of  which  are  notched  at  the  upper  extre- 
mity. In  the  Argonaut  the  two  lobes  are 
united  for  a  considerable  extent  along  the 
mesial  line,  but  are  greatly  produced  laterally, 
and  advance  forwards,  narrowing  towards  a 
point,  so  as  partially  to  enclose  the  alimentary 
canal.  In  Octopus  the  liver  is  a  single  oval 
mass,  flattened  anteriorly.  In  Eledone  it  pre- 
sents a  spherical  form,  corresponding  to  the 
ventricose  form  of  the  visceral  sac.  In  the  two 
latter  genera  the  ink-bag  is  enclosed  within  the 

*  n>5pa»0flc,  mutilaius,  a  name  applied  to  this 
genus  by  Eschscholtz,  in  consequence  of  the  gene- 
rally mutilated  condition  of  the  tentacles.  See 
Mem.  de  1'Acad.  Imp.  de  Petersbourg,  torn.  ii.  pt. 
1  &  2,  p.  149. 

VOL.  I. 


capsule  of  the  liver,  but  in  the  Argonaut  and  in 
all  the  Decapodous  genera  this  is  not  the  case. 
The  proper  capsule  of  the  liver  is  very  delicate, 
and  apparently  nothing  more  than  the  outer  ter- 
mination of  the  cellular  tissue  which  connects 
the  lobules  of  its  parenchyma.  When  this  is 
inflated  from  the  biliary  ducts,  it  is  seen  to  be 
composed  of  cells, 
formed  by  the  ulti- 
mate ramifications  of 
the  duct,  with  very 
thin  parietes,  and  re- 
latively larger  than 
those  of  the  liver  of 
the  Snail.  This  is  the 
structure  observable 
in  the  liver  of  the 
Octopus,  according 
to  Miiller,*  and 
Rathke'  observed  the 
same  structure  in 
the  terminal  coeca  of 
the  hepatic  duct  in 
Loligopw. 

In  the  Octopo- 
dous  Dibranchiates, 
which  have  a  large 
crop,  and  the  lower 
pair  of  salivary 
glands  of  corres- 
pondingly large  di- 
mensions, the  two 
biliary  ducts  are 
simple  canals,  which 
are  continued  from 
the  lower  end  of  the 
liver,  embracing  the 
origin  of  the  intes- 
tine, and  uniting  be- 
low it  to  terminate 
by  a  common  orifice 
in  the  pyloric  ap- 
pendage. Butinthe 
Decapodous  tribe 
they  continue  to  send 
off  branches,  which 
subdivide  and  form 
clusters  of  ccecal  appendages,  through  a  greater 
or  less  proportion  of  their  entire  course.  The 
follicles  thus  appended  to  the  biliary  ducts 
are  larger  than  those  which  form  the  liver ;  they 
are  figured  by  Monro  in  the  Loligo  sagittata 
as  the  ovary,  but  were  considered  by  Mr. 
Hunter  to  represent  the  pancreas  in  the  Cuttle- 
fish, from  which  species  he  took  the  preparation 
of  these  parts  in  his  collection.f  These  folli- 
cles are  described  with  much  care  and  detail 
by  Rathke  in  the  genus  Loligopsis,  and,  ac- 
cording to  him,  in  one  species  (10,  Jig.  223), 
(Lol.  Eschscholtzii,)  they  terminate,  not  in  the 
hepatic  duct,  but  separately  and  directly  in  the 
pyloric  appendage.  We  have  found  these 
cystic  follicles  appended  to  the  hepatic  duct  in 
Scpiola,  Onychoteuthis,  Sepiotcuthis,  and  in 
the  genus  Rossia,  in  which  they  present  the 
largest  proportional  development  hitherto  ob- 

*  De  Glandularum  Struct.  Pen.  p.  71. 
t   See    No.    775,     Physiological    Caialogne,     4to. 
vol.  i.  p.  229. 

2  N 


2- 


Viscera  in  situ,  Loligopsis. 
Lol.  Eachscholtxii. 


,38 


CEPHALOPODA. 


served  in  the  class.  Here  the  biliary  ducts,  as 
soon  as  they  emerge  from  the  liver,  branch  out 
into  an  arborescent  mass  of  larger  and  more 
elongated  follicles  than  those  constituting  the 
hepatic  parenchyma;  these  ramifications  extend 
full  half  an  inch  from  the  hepatic  duct,  and 
conceal  the  upper  halves  of  both  the  stomach 
and  pyloric  appendage. 

Organs  of  Circulation. —  Prior  to  the  dis- 
section of  the  Nautilus  Pompilius  the  Ce- 
phalopods  were  regarded  as  having  three  dis- 
tinct hearts,  a  peculiarity  which  is  not  found  in 
the  circulating  system  of  any  other  class  of 
animals.  In  the  Nautilus,  however,  there  is 
but  one  ventricle,  which  is  systemic,  as  in  the 
inferior  Mollusks;  and  the  three  hearts  are, 
therefore,  characteristic  only  of  the  Dibran- 
chiate  or  higher  order  of  Cephalopods. 

These  differences  in  the  circulating  system  of 
the  two  orders  are  accompanied  with  equally  well 
marked  modifications  of  the  respiratory  organs ; 
and  hence  the  primary  divisions  of  the  class 
are  each  distinguished  by  characters  of  equal 
value,  and  derived  from  modifications  of  those 
organs  which  afford  the  most  natural  indica- 
tions of  the  corresponding  groups  in  the  other 
classes  of  the  Molluscous  division  of  Inverte- 
brate animals. 

In  the  Nautilus  the  veins  which  return  the 
blood  from  the  labial  and  digital  tentacles  and 
adjacent  parts  of  the  head  and  mouth,  termi- 
nate in  the  sinus  excavated  in  the  substance  of 


the  cephalic  cartilage.  From  this  sinus  the  great 
anterior  vena  cava  (a,  Jig.  224)  is  continued, 
running  in  the  interspace  of  the  shell-muscles 
on  the  ventral  aspect  of  the  abdominal  cavity, 
and  terminating  in  a  sinus  (6)  just  within  the 
pericardium,  where  it  receives  the  venous 
trunks  of  the  viscera.  (These  are  indicated  by 
bristles  in  the  figure.) 

The  structure  of  the  vena  cava  is  very  remark- 
able ;  it  is  of  aflaltened  form,  being  included  be- 
tween a  strong  membrane  on  the  lower  or  ventral 
aspect,  and  a  layer  of  transverse  muscular  fibres, 
which  decussate  each  other  on  the  upper  or  dorsal 
aspect;  both  the  membrane  and  the  muscle 
pass  across  from  the  inferior  margin  of  one 
shell-muscle  to  the  other;  they  consequently 
increase  in  breadth  as  those  muscles  diverge, 
and  complete  the  parietes  of  the  abdomen  on 
the  ventral  aspect.  The  vein,  however,  main- 
tains a  more  uniform  calibre  by  its  proper 
internal  coat,  leaving  a  space  on  either  side 
between  the  membrane  and  muscle.  The  ad- 
hesion of  the  proper  membrane  to  the  muscular 
fibres  is  very  strong,  and  these,  though  ex- 
trinsic to  the  vessel,  form  part  of  its  parietes 
on  the  dorsal  aspect.  There  are  several  small 
intervals  left  between  the  muscular  fibres  and 
corresponding  round  apertures  (a')  in  the  mem- 
brane of  the  vein  and  contiguous  peritoneum,  by 
which  the  latter  membrane  becomes  continuous 
with  the  lining  membrane  of  the  vein  :  from 
this  structure  it  would  seem  that  the  blood 


Fig.  224. 


Circulating  and  Respiratory  Organs,  Nautilus  Pompilius. 


CEPHALOPODA. 


539 


might  flow  into  the  peritoneal  cavity,  or  the 
fluid  contents  of  that  cavity  be  absorbed  into 
the  vein.* 

In  the  structure  of  the  other  veins  of  the 
Nautilus  nothing  uncommon  is  observed  : 
their  principal  termination  is  in  the  sinus 
above-mentioned,  where  the  greater  or  systemic 
circulation  ceases,  if  we  are  to  consider  the 
lesser  circulation  to  commence  where  the  blood 
again  begins  to  move  from  trunks  to  branches. 

Four  vessels,  which,  according  to  the  above 
view,  are  analogous  to  branchial  arteries,  (c,  c,) 
arise  from  the  sides  of  the  sinus,  and  proceed, 
two  on  each  side,  to  their  respective  gills.  In 
this  course  they  have  each  appended  to  them 
three  clusters  of  short,  pyriform,  closely  aggre- 
gated, glandular  follicles  (d,  d).  The  larger 
cluster  is  situated  on  one  side  of  the  vessel, 
and  the  two  smaller  on  the  opposite.  Each  of 
these  clusters  is  contained  in  a  membranous 
receptacle  communicating  with  the  pericar- 
dium, and  formed  by  partitions  projecting  from 
its  inner  surface.  In  these  partitions  we  ob- 
served a  fibrous  texture,  which  conveyed  an 
impression  that  they  were  for  the  purpose  of 
compressing  the  follicles  and  of  discharging 
such  fluids  as  might  exude  through  their  pa- 
rietes  into  the  pericardium,  whence  it  might  be 
expelled  by  the  papilliform  apertures  at  the 
base  of  the  gills  into  the  branchial  cavity .f 
The  follicles,  however,  terminate  by  their  pro- 
per apertures  in  the  interior  of  the  dilated  parts 
of  the  vessels  to  which  they  are  appended : 
(these  are  shewn  on  the  right  side  atd',d'.)  We 
shall  revert  to  these  singular  bodies  in  the  de- 
scription of  the  circulating  organs  of  the  Di- 
branchiata. 

The  branchial  arteries  having  reached  the 
roots  of  the  gills  become  contracted  in  size, 
and  their  area  is  here  occupied  by  a  valve  which 
opposes  the  retrogression  of  the  blood.  Each 
vessel,  then,  penetrates  the  fleshy  stem  of  the 
branchia  (e),  where  it  dilates  into  a  wide 
canal,  which  presents  a  double  series  of  orifices 
through  which  the  blood  is  driven  by  the 
contraction  of  the  surrounding  muscular  sub- 
stance, into  the  vessels  which  extend  along  the 
concave  margins  of  the  branchial  laminae. 

The  branchial  vein  (f)  receives  the  aerated 
blood  from  vessels  extending  along  the  convex 
margins  of  the  respiratory  laminae,  by  a  series 
of  alternate  slits,  and  is  continued  down  the 
anterior  or  inner  side  of  the  gill.  After  quit- 
ting the  roots  of  the  gills  each  vein  crosses  its 
corresponding  artery  on  the  dorsal  aspect,  and 
is  continued,  without  forming  a  dilatation  or 
sinus,  to  the  systemic  ventricle,  where  regurgi- 
tation  is  prevented  by  a  single  semilunar  valve 
at  the  termination  of  each  vein. 

The  ventricle  (p)  is  of  a  somewhat  com- 
pressed and  transverse  quadrate  form  :  its  mus- 
cular parietes  are  nearly  a  line  in  thickness, 
and  present  internally  a  decussated  structure. 

*  For  a  further  description  of  this  structure,  its 
analogies,  and  probable  uses,  see  '  Memoir  on  the 
Pearly  Nautilus,'  p.  27  et  seq. 

t  We  found  the  pericardium  in  the  specimen 
dissected  filled  with  coagulated  matter  accurately 
moulded  to  the  different  parts  which  contained  it. 


Two  arteries  arise  from  it ;  one  superior  and 
small  (h)y  whose  orifice  is  furnished  with  a 
double  valve ;  the  other  inferior  and  of  large 
size  (i),  coming  off  from  near  the  left  angle  of 
the  ventricle,  and  furnished  with  a  muscular 
bulb  about  five  lines  long,  at  the  termination 
of  which  there  is  a  single  valve ;  and  which 
ought  rather  to  be  considered  as  a  continuation 
of  the  ventricle.  The  lesser  aorta  gives  off  a 
branch  to  the  great  gland  of  the  oviduct;  a 
second,  which  is  continued  down  the  membra- 
nous siphuncle  of  the  shell ;  and  a  third  to  the 
fold  of  intestine  (I).  The  larger  aorta  passes 
downwards  between  the  gizzard  and  ovary,  and 
renders  vessels  to  both  these  viscera.  It  then 
winds  round  the  bottom  of  the  pailial  sac,  sends 
off  large  branches  to  the  liver,  and  gains  the  dorsal 
aspect  of  the  crop,  along  which  it  is  continued, 
distributing  branches  on  either  side  to  the 
great  shell-muscles,  to  the  cephalic  cartilage, 
where  it  divides  into  two  equal  branches, 
which  pass  round  the  sides  of  the  oesophagus, 
and  furnish  branches  to  the  mouth,  the  sur- 
rounding parts  of  the  head  and  the  funnel. 

In  the  Dibranchiata  the  veins  of  each  arm 
form  two  principal  branches,  which  descend 
along  the  lateral  and  posterior  parts  of  those 
appendages;  each  lateral  vein  unites  at  the  base 
of  the  arm  with  the  opposite  vein  of  the  adjoin- 
ing arm ;  the  united  vessel  is  joined  by  another 
similarly  formed  ;  and  the  whole  of  the  venous 
blood  is  thus  ultimately  conveyed  to  an  irre- 
gular circular  sinus,  from  the  anterior  part  of 
which,  between  the  head  and  the  funnel,  the 
great  anterior  cava  is  continued.  In  the  Octo- 
pus this  vessel  (a,  Jig.  226)  is  provided  with 
two  semilunar  valves,  where  it  communicates 
with  the  venous  circle.  A  little  below  this 
part  it  receives  the  veins  of  the  funnel ;  then 
those  of  the  anterior  part  of  the  liver  ( b)  and 
of  its  muscular  envelope.  Upon  its  entrance 
into  the  pericardium  the  vena  cava  divides 
without  forming  a  sinus  as  in  the  Nautilus  ; 
and  sometimes  before,  sometimes  after  its  divi- 
sion it  is  joined  by  two  large  visceral  veins 
(c).  Thus  reinforced,  each  of  the  divisions 
(d,  d)  proceeds  downwards  and  outwards  to 
the  lateral  or  branchial  heart  of  its  correspond- 
ing side;  but  previous  to  opening  into  the 
ventricle  it  dilates  into  a  sinus  (e),  which  also 
receives  the  venous  blood  from  the  sides  of  the 
mantle  and  the  fleshy  and  vascular  stem  of  the 
branchia,  by  the  vein  marked  f. 

Both  the  divisions  of  the  vena  cava  and  the  two 
visceral  veins,  after  having  entered  the  pericar- 
diac  or  venous  cavity,  are  furnished  with  clusters 
of  spongy  cellular  bodies  (g,  g),  which  open 
into  the  veins  by  conspicuous  foramina,  like  the 
venous  follicles  of  the  Nautilus  above  described. 

In  no  species  of  Cephalopod  which  has  hi- 
therto been  anatomized,  have  these  appendages* 
been  found  wanting ;  but  they  vary  in  form  in 
different  genera.  In  the  Genus  Eledone-\-  they 

*  From  a  consideration  of  the  different  particu- 
lars given  in  Aristotle's  anatomical  description  of 
the  Cephalopods,  Kbhler  supposes  the  part  which 
he  calls  /uy'rif,  mytis,  to  have  been  the  glandular 
appendages  of  the  veins  above  described. 

t  Carus,  Vergleich.  Zootomie,  tab.  iv.  fig.  viii. 
x,  Eledone  Moschata. 

2  N   2 


540 


CEPHALOPODA. 
Fig.  225. 


Circulating  and  respiratory  organs— Cuttle-fish* 


form  thin  colourless  pyriforrn  sacs,  extending 
nearly  an  inch  from  the  vein.  They  are  ar- 
ranged in  distinct  clusters,  and  are  relatively 
shorter  in  Argonauta.  In  Sepioteuthis  the 
whole  extent  of  the  superior  and  inferior  trunks 
of  the  veins  contained  in  the  pericardium  pre- 
sent an  uniform  and  continuous  cellular  en- 
largement of  their  parietes.  In  Loligo  the 
coats  of  the  corresponding  veins  in  like  man- 
ner present  only  a  spongy  thickening.  In 
Sepia  the  cells  are  more  elongated,  but  are 
large,  irregular,  and  flocculent  ( c,-c,  fg.  225), 
and  continued  without  interruption  not  only 
upon  the  divisions  of  the  vena  cava  (a),  but 
upon  the  visceral  veins,  two  of  which  ( b,  b) 
present  remarkable  dilatations. 

In  Loligopsis  the  venous  follicles  are  in 
distinct  groups,  as  in  Nautilus ;  and  Rathke" 
describes  them  as  presenting  a  laminated  and 
glandular  structure. 

With  respect  to  the  function  of  these  bodies 
nothing  is  as  yet  definitely  known.  They  are 
well  supplied  with  blood  from  the  neighbouring 
arteries,  and  are  undoubtedly  glandular;  but 
the  matter  which  they  secrete  has  not  yet  been 
subjected  to  chemical  analysis.  If  the  spongy 
coats  of  the  vena  cava  of  a  Calamary  be 
pressed,  a  whitish  fluid  escapes,  which  is  al- 

*  From  Home's  Comparative  Anat.  vol.  iv.  See 
the  original  figure  and  description  by  Hunter,  in 
Descr.  Catalogue  of  Mus.  R.  Coll.  of  Surgeons, 
vol.  ii.  pi.  xxii. 


ways  thicker  and  more  turbid  than  the  blood 
which  circulates  in  the  vein.  The  elongated 
cells  of  the  Poulp  yield  in  like  manner  an 
opake  and  yellow  mucus.  Some  physiologists 
suppose  that  the  secreted  matter  is  not  expelled 
by  the  orifices  of  the  sacs  into  the  veins  to  be 
mixed  with  the  current  of  blood,  but  that  the 
venous  blood  passes  into  the  cells  by  those 
apertures,  and  that  the  matter  secreted  from  it 
exudes  from  the  parietes  of  the  cells  or  follicles 
into  the  great  serous  cavity  surrounding  them. 
Mayer,  considering  that  the  urine  is  secreted 
from  venous  blood  in  the  lower  vertebrate 
animals,  regards  these  venous  appendages  as 
the  renal  organs  of  the  Cephalopods ;  the  serous 
sacs  (h,  fig.  226),  therefore,  which  Cuvier  calls 
the  i  great  venous  cavities,'  and  which  we  have 
termed  the  *  pericardium/  the  German  Physi- 
ologist calls  the  «  urinary  bladder;'  and  the 
papillary  orifices  (i)  leading  into  the  branchial 
or  excrementory  chamber,  which  we  have  com- 
pared with  the  orifices  leading  from  the  peri- 
cardium of  the  Ray  and  Sturgeon  into  the 
peritoneal  cavity  of  the  abdomen,f  Mayer  calls 
the  urethrae.  It  must  be  observed,  however, 
that  this  Physiologist  does  not  advance  any 
proof  from  chemical  analysis  in  support  of  his 
theory.  Cuvier,  on  the  other  hand,  believing  that 
the  water  of  the  branchial  chamber  might  have 
access  by  the  orifices  to  the  cavities  containing 
the  appendages  in  question,  supposes  that  they 

t  Memoir  on  the  Nautilus,  p.  33. 


CEPHALOPODA. 


541 


Fig.  226. 


Viscera  of  Poulp* 

may  serve  as  accessory  respiratory  organs.  The 
valvular  structure  of  the  orifices  is  opposed, 
however,  to  this  view;  while  it  supports  the 
doctrine  of  their  being  excretory  outlets. 

The  venous  follicles  may,  therefore,  serve  as 
emunctories,  by  means  of  which  the  blood  is 
freed  of  some  principle  that  escapes  from  their 
external  pores ;  or  they  may  alter  the  blood  by 
adding  something  thereto ;  or,  like  the  spleen, 
they  may  assist  in  converting  arterial  to  venous 
blood.  As  a  secondary  function  they  may 
serve  as  temporary  reservoirs  of  the  venous 
blood  whenever  it  accumulates  in  the  vessels 
either  from  a  general  expansion,  or  from  a  partial 
impediment  in  its  course  through  the  respi- 
ratory organs ;  and  thus  the  cells  or  follicles, 
which  are  endowed  with  a  motion  of  systole 
and  diastole,  like  the  auricles  of  the  heart,  may 
serve  to  regulate  the  quantity  of  blood  trans- 
mitted to  the  gills. 

The  branchial  ventricles  (d,  d,fg.  225)  are 
appended  to  the  roots  of  the  gills  :  in  the  Octo- 
poda  they  are  simple  pyriform  muscular  cavities 
(k,  k,fg.  226,)  generally  of  a  blackish  grey  co- 
lour ;  in  the  Decapoda  they  are  elliptical  or  trans- 
versely oblong,  of  a  light  grey  or  pale  red  co- 
lour, and  have  a  white  fleshy  appendage  ( e,  e, 
^g.  225,)  hanging  to  their  lower  surface  or 
their  external  side.  The  connecting  pedicle  is 
hollow,  and  communicates  with  a  small  cavity 
in  the  substance  of  the  appendix.  Internally 
these  ventricles  are  deeply  impressed  with  cells 

*  From  Mayer,  Analecteu  fur  Vergleichende 
Anatomic,  tab.  v. 


and  decussating  carneae 
columntE  ( k,fg.  226), 
and  where  they  com- 
municate with  the  ve- 
nous sinus  two  semi- 
lunar  valves  (I)  are 
placed  to  prevent  re- 
gurgitation  .  Their  func- 
tion is  to  accelerate 
the  circulation  through 
the  branchiae  ;  and  by 
this  simple  addition  to 
the  respiratory  appa- 
ratus, the  two  gills  of 
the  Dibranchiata  are 
rendered  equal  to  the 
office  of  preparing  the 
blood  to  maintain  the 
increased  muscular  ex- 
ertions, and  repair 
all  the  corresponding 
waste  which  the  vital 
economy  of  this  highly 
organized  group  of 
Molluscous  animals 
occasions. 

The  branchial  veins 
(m,m,fgs.  225,  226) 
return,  as  in  the  Nauti- 
lus,along  the  internal  or 
unattached  side  of  the 
commissure  of  thebran- 
chial  laminae ;  and,  as 
they  approach  the  sys- 
temic ventricle,  generally  dilate  into  a  sinus  (n) 

Fig.  227. 


Systemic    Ventricle,  Onychoteuthis. 


542 


CEPHALOPODA. 


on  each  side  :  these  sinuses  are  relatively  larger 
in  the  Sepia  than  the  Octopus.  In  both  species 
the  branchial  vein  resumes  its  ordinary  dimen- 
sions before  terminating  in  the  ventricle ;  but  in 
the  Cuttlefish  the  sinus  is  placed  closer  to  the 
ventricle. 

The  systemic  ventricle  (o)  is  situated  in  the 
mesial  plane  between  the  bifurcation  of  the 
vena  cava  above,  and  the  ovary  or  testis  below. 
In  the  Octopus  and  Eledone  it  presents  a  glo- 
bular form,  rather  extended  tranversely,  and 
with  the  branchial  sinus  entering  at  its  superior 
and  lateral  aspects.  In  the  Loligo  and  the 
Onychoteuthis  (Jig-  227)  it  is  lozenge-shaped, 
with  the  long  axis  in  the  axis  of  the  body ; 
giving  off  the  two  aortse  (c,  d)  by  the  anterior 
and  posterior  angles,  and  receiving  the  bran- 
chial veins  (a,  a,)  at  the  lateral  angles.  In  the 
Sepia,  (o,  jig.  225,)  Sepioteuthis,  and  Rossia, 
the  systemic  ventricle  is  a  fusiform  body,  bent 
upon  itself  at  right  angles.  About  one-half  on 
the  right  side  lies  in  the  axis  of  the  body,  the 
remainder  extends  transversely  to  the  left  side ; 
the  extremity  of  this  part  receives  the  left  bran- 
chial vein,  the  other  extremity  gives  off  the  an- 
terior aorta  (q,  Jig,  225).  The  bulb  of  the 
posterior  and  generally  the  larger  aorta  (p,  Jig. 
225)  is  continued  from  the  middle  of  the 
transverse  portion;  the  right  branchial  vein 
enters  the  middle  of  the  right  side  of  the  lon- 
gitudinal portion  of  the  ventricle. 

In  all  the  Dibranchiata  the  parietes  of  the 
systemic  heart,  though  thin,  are  firmer  and  more 
muscular  than  those  of  the  branchial  hearts;  and 
its  cavity  is  generally  about  three  times  greater 
than  that  of  either  of  the  others:  its  inner 
surface  shows  the  regular  interlacement  and 
decussation  of  the  columnse  carneae,  none 
of  which,  however,  project  into  the  cavity. 
The  termination  of  each  branchial  vein  is 
defended  by  a  pair  of  membranous  semi- 
lunar  valves  (b,  jig.  227).  The  origin  of  the 
lesser  aorta  (p),  arising  from  the  anterior  part 
of  the  ventricle,  is  defended  by  a  single  valve 
(e,fig.  227);  that  of  the  great  aorta,  (q',fig. 
226,)  which,  though  posterior  in  its  origin,  is  de- 
stined to  supply  the  head  and  anterior  parts  of 
the  body,  is  generally  provided  with  a  mus- 
cular bulb,  as  in  the  Nautilus.  In  the  Octopus 
it  is  defended,  according  to  Cuvier,  by  two 
semilunar  valves;  but  in  the  Calamary  and 
Onychoteuthis  by  a  single  valve  (f,  Jig.  227). 
In  the  Octopus  there  is  also  a  third  small 
artery  (r,  fig.  225)  given  off  directly  from  the 
ventricle,  which  is  distributed  to  the  generative 
organs,  and  presents  considerable  periodical 
variations  of  size  in  relation  to  the  functions 
of  those  parts.  In  the  same  genus  the  small 
aorta,  which  arises  from  the  anterior  part  of 
the  ventricle,  first  gives  off  two  long  and  slender 
branches  (*,  *,  fig.  226),  which  are  distributed 
to  the  venous  follicles,  whose  arterial  vascularity 
we  have  before  mentioned.  The  trunk  then  di- 
vides into  two  arteries,  of  which  the  largest  (t) 
ascends  in  front  of  the  vena  cava  to  be  distri- 
buted to  the  mantle;  the  other  supplies  the 
folded  intestine  and  surrounding  peritoneum. 
The  large  aorta  first  passes  backwards  and  to 
the  right  between  the  layers  of  peritoneum 


which  separate  the  intestinal  sac  from  that  of 
the  pyloric  appendage  and  that  of  the  stomach; 
winds  round  the  latter,  and  passes,  by  a  proper 
opening,  to  the  right  of  the  cardia  through  the 
muscular  septum,  and  into  the  cavity  behind 
the  liver,  and  ascends  on  the  right  side  of  the 
dilated  oesophagus  to  the  cartilaginous  cranium. 
Here,  after  distributing  branches  to  the  sur- 
rounding parts,  it  bifurcates  and  completely 
encircles  the  gullet;  and  from  this  vascular 
ring,  which  is  strikingly  analogous  to  the  bran- 
chial arches  in  Vertebrata,  the  head  and  all  its 
complex  radiating  appendages  derive  their  nu- 
triment. 

RESPIRATORY  ORGANS. — The  branchiae  pre- 
sent the  same  general  form  and  structure  in  both 
orders  of  Cephalopods,  but  differ,  as  before  ob- 
served, in  number,  and  also  in  their  mode  of 
attachment  to  the  mantle.  They  are  always 
entirely  concealed  and  protected  by  the  mantle, 
which  is  extended  forwards  so  as  to  form  a 
peculiar  chamber  for  them  anterior  to  the  other 
viscera,  and  into  which  the  rectum  and  gene- 
rative organs  open.  It  is  interesting  to  perceive 
the  respiratory  cavity  retaining,  in  the  highest 
organized  Mollusks,  that  relation  with  the  anal 
extremity  of  the  digestive  canal  which  we  trace 
through  the  whole  of  this  type  of  animal  con- 
formation, and  which  forms  so  well-marked  a 
line  of  distinction  between  the  Molluscous  and 
Vertebrate  divisions  of  the  animal  kingdom. 

In  the  Nautilus  the  four  branchiae  are  at- 
tached by  their  bases  only  to  the  inner  surface  of 
the  mantle;  but  in  the  Dibranchiates  a  thin 
fibrous  membrane  connects  the  fleshy  stem  of 
each  gill  to  the  contiguous  surface  of  the  man- 
tle. In  the  Nautilus  the  branchiae  are  subject 
to  contortions  from  the  want  of  this  support ; 
and  in  the  specimen  which  we  dissected,  we 
found  the  gills  on  one  side  closely  bent  upon 
themselves,  with  their  apices  turned  down;  this 
circumstance  does  not  probably  impede  a  cir- 
culation which  flows  with  an  equable  and  con- 
tinuous current  through  the  gill ;  but  where  the 
blood  is  driven  in  jerks  by  the  contractions  of 
a  powerful  ventricle,  a  necessity  then  exists  for 
the  provision  of  a  free  channel  for  the  passage  of 
the  fluid  ;  and  accordingly  we  find  that  the 
obstruction  of  the  branchial  artery  by  the 
bending  of  the  fleshy  stem  of  the  gill  is  obvia- 
ted by  the  simple  but  effectual  means  above 
described,  viz.  the  superaddition  of  a  connect- 
ing membrane,  which  always  preserves  the  gill 
in  a  straight  position. 

In  both  orders  of  Cephalopoda  the  branchiae 
present  an  elongated  pyramidal  figure,  with  their 
apices  directed  forwards  :  they  are  compressed 
from  before  backwards  in  the  Nautilus  ( n,  m, 
Jig.  224),  and  from  side  to  side  in  the  Cuttle-fish 
(i,  k,  Jig.  225)  and  most  other  Dibranchiates. 
They  are  composed  of  a  number  of  triangular 
vascular  laminae  extendingtransversely  from  each 
side  of  a  central  fleshy  stem  (h,fg.  225),  having 
an  alternate  disposition  :  each  lamina  is  com- 
posed of  smaller  transverse  laminae,  which  are 
again  similarly  subdivided ;  the  entire  gill  thus 
exhibiting  the  structure  called  by  botanists  *  tri- 
pinnate,'  by  which  an  extensive  surface  is  afford- 
ed for  the  minute  division  of  the  branchial  vessels. 


CEPHALOPODA. 


543 


In  the  Nautilus  (Jig-  224)  there  is  a  larger  and 
smaller  branchia  on  each  side;  the  larger  and 
external  branchia  (m)  presents  forty-eight  pairs 
of  laminae;  the  smaller  branchia  (n)  thirty-six. 

In  the  Dibranchiates  the  gills  vary  in  the 
relative  size  and  number  of  laminae  in  different 
genera;  they  are,  perhaps,  proportionally  small- 
est in  the  Loligopsis,  where,  according  to 
Rathke,  the  number  of  branchial  laminae  does 
not  exceed  twenty-four  pairs ;  and  it  is  inte- 
resting to  observe  in  this  genus  that  the  mus- 
cular structure  of  the  mantle  has  a  correspond- 
ingly feeble  development.  In  the  Cuttle-fish 
the  branchiae  are  each  composed  of  thirty-six 
pairs  of  triangular  laminae :  in  the  Sagittated 
Calamary  of  sixty  pairs  of  laminae. 

As  the  branchiae  of  the  Cephalopods  are  un- 
provided with  vibratile  cilia,  respiration  is 
effected  by  the  alternate  dilatation  and  contrac- 
tion of  the  branchial  chamber ;  in  the  first  ac- 
tion the  sea-water  rushes  in  by  the  anterior  aper- 
ture of  the  mantle ;  by  the  second  it  is  expelled 
through  the  cavity  of  the  funnel.  As  in  other 
classes,  respiration  is  performed  more  quickly 
in  the  young  than  in  the  full-grown  animals  : 
Dr.  Coldstream  witnessed  an  Eledone,  which 
measured  one  inch  and  a  half  in  length,  respire 
eighteen  times  in  a  minute;  while  one  of  the 
same  species,  which  measured  four  inches  in 
length,  respired  ten  times  in  a  minute.  The 
proper  direction  of  the  respiratory  currents  is 
insured  by  various  mechanical  contrivances  ;  in 
the  Nautilus,  the  funnel  passes  through  a  hole  in 
the  substance  of  the  mantle,  which  fits  it  so 
closely,  that  at  the  moment  when  the  funnel  is 
distended  by  the  expiratory  stream,  no  space  is 
left  external  to  it  by  which  the  water  can 
escape  ;  and  the  greater  the  force  by  which  the 
water  is  driven  into  the  funnel,  the  closer  is  it 
girt  by  the  mantle.  In  the  Poulp  and  Eledone, 
where  the  funnel  is  connected  to  the  fore  part 
of  the  neck,  and  the  mantle  passes  across  its 
base,  two  large  valvular  folds  (one  of  which  is 
shown  at  v,Jig.  216)  are  extended  from  its  sides; 
these  are  concave  towards  the  respiratory  sac; 
they  subside  during  inspiration,  and  the  parietes 
of  the  funnel  at  the  same  time  are  collapsed ; 
the  latter  during  expiration  are  dilated,  while 
the  valves  are  raised  and  expanded,  and  thereby 
prevent  the  ejected  currents  from  passing  out- 
side the  funnel.  In  the  Argonaut,  and  in 
all  the  Decapods,  except  the  Loligopsis  and 
Cranchia,  the  sides  of  the  funnel  are  articula- 
ted to  the  opposite  sides  of  the  mantle  by  ball- 
and-socket  joints,  which  produce  so  close  an 
apposition  of  the  anterior  free  margin  of  the 
mantle  with  the  parts  it  surrounds,  that  upon 
its  contraction,  no  other  outlet,  save  the  funnel, 
is  left  for  the  expiratory  currents.  In  the  Ar- 
gonaut the  pallial  eminence  is  a  round  tuber- 
cle, below  which  is  a  small  cavity,  and  these 
are  adapted  to  a  cavity  and  tubercle  of  corre- 
sponding form  at  the  side  of  the  funnel.  In 
Sepia,  the  articular  tubercle  is  elongated  in  the 
direction  of  the  axis  of  the  body,  and  is  of  an 
oval  form.  In  Loligo  and  Onychoteuthis  it  is 
still  more  elongated  and  narrow,  and  the  arti- 
cular depression  is  conformable  :  in  Loligopsis 
the  corresponding  cartilage  is  no  longer  sub- 


servient to  an  articulation  with  the  funnel,  but 
is  represented  by  a  series  of  wart-like  knobs. 

TEGUMENTARY  SYSTEM. — The  skin  of  the 
Cephalopods  is  thin  and  lubricous,  and  can 
be  more  easily  detached  from  the  subjacent 
muscles  than  in  the  inferior  Molluscous  classes. 
In  the  Poulp,  Eledone,  Argonaut,  Cuttle-fish, 
and  Sepiola,  its  texture  is  soft  and  tender,  and 
the  whole  mantle  is  semitransparent  in  some 
species,  as  the  Octopus  hyalinus ;  but  in  the 
Calamaries  and  Onychoteuthides  it  is  thicker, 
harder,  and  more  unyielding ;  it  is  interesting 
to  observe  that  it  is  in  these  latter  genera  that 
the  epidermoid  system  is  most  developed,  as. 
is  exemplified  in  the  horny  denticulations  and 
hooks  upon  the  acetabula. 

In  the  Cuttle-fish  the  suckers  are  provided 
with  simple  unarmed  horny  rings.  In  the 
Octopods  the  epidermis  is  reflected  over  the 
interior  of  the  suckers  without  being  thickened 
into  a  horny  substance  at  that  part.  In  the 
body  generally  the  epidermis  is  readily  de- 
tached by  maceration,  and  forms  a  thick,  white, 
elastic,  semitransparent,  external  layer. 

The  colorific  stratum  of  the  integument  forms, 
both  in  its  structure  and  vital  phenomena,  one 
of  the  most  curious  and  interesting  parts  of  the 
organization  of  this  singular  class  of  animals ; 
and  the  nature  of  which,  when  thoroughly  un- 
derstood, may  be  expected  to  elucidate  the 
mysterious  operations  of  light  in  producing 
and  affecting  the  colours  of  animals. 

This  stratum,  which  is  analogous  to  the 
rete  mucosum,  consists  of  a  very  lax  and 
fine  vascular  and  nervous  cellular  tissue,  con- 
taining an  immense  number  of  small  closed 
vesicles,  which  vary  in  relative  sizes  in  different 
species  of  Dibranchiata.  These  vesicles  are  of 
a  flattened  oval  or  circular  form,  and  contain  a 
fluid  in  which  is  suspended  a  denser  colouring 
matter.  The  colour  is  not  always  the  same  in 
all  the  vesicles,  but  in  general  corresponds 
more  or  less  closely  with  the  tint  of  the  secre- 
tion of  the  ink-bag.  This,  for  example,  is  the 
case  in  Sepiola,  in  which  all  the  vesicles  con- 
tain material  of  the  same  colour.  In  Sepia,  be- 
sides the  vesicles  which  correspond  to  the  ink 
in  the  colour  of  their  contents,  there  is  another 
series  of  an  ochre  colour.  In  Loligo  vulgaris 
there  are  three  kinds  of  coloured  vesicles,  yel- 
low, rose-red,  and  brown.  In  Loligo  sagittata 
there  are  four  kinds,  saffron,  rose-red,  deep 
blue,  and  light  blue.  In  Octopus  vulgaris  there 
are  also  four  orders  of  vesicles,  viz.  saffron,  red, 
blackish,  and  blueish.  The  Argonauta  Argo 
possesses  vesicles  of  all  the  colours  which  have 
been  observed  in  other  Cephalopods,  and  hence 
the  variety  and  change  of  colour  which  the 
surface  of  its  skin  presents  when  exposed  to 
the  light. 

These  vesicles  have  no  visible  communica- 
tion either  with  the  vascular  or  the  nervous 
systems,  or  with  each  other  :  yet  they  exhibit, 
during  the  life-time  of  the  animal,  and  long 
after  death,  rapid  alternating  contractions  and 
expansions.*  If,  when  the  animal  is  in  a  state 

*  Conf.  Dr.  Coldstream  in  Edinb.  Journal  of 
Natural  and  Geographical  Science,  vol.  ii.  p.  297. 


544 


CEPHALOPODA. 


of  repose,  and  the  vesicles  are  contracted  and 
invisible,  the  skin  be  slightly  touched,  the  co- 
loured vesicles  show  themselves,  and  in  an  in- 
stant, or  sometimes  with  a  more  gradual  mo- 
tion, the  colour  will  be  accumulated  like  a 
cloud  or  a  blush  upon  the  irritated  surface.  If 
a  portion  of  the  skin  be  removed  from  the 
body  and  immersed  in  sea-water,  the  lively 
contractions  of  the  vesicles  continue ;  when 
viewed  in  this  state  under  the  microscope  by 
means  of  transmitted  light,  the  edges  of  the 
vesicles  are  seen  to  be  well  defined,  and  to  pass 
in  their  dilatations  and  contractions  over  or 
under  one  another.  If  the  separated  portion  of 
integument  be  placed  in  the  dark,  and  exa- 
mined after  a  lapse  of  ten  or  fifteen  minutes, 
all  motion  has  ceased;  but  the  vesicles,  when 
re-exposed  to  a  moderately  strong  light,  soon,  in 
obedience  to  that  stimulus,  recommence  their 
motions.  As  the  vibratile  microscopic  cilia 
have  been  recently  traced  through  the  higher 
classes  of  the  animal  kingdom,  it  is  not  an  un- 
reasonable conjecture  that  equally  inexplicable 
motions  of  the  colouring  parts  of  the  integu- 
ment may  also  be  detected  in  other  classes 
than  that  in  which  we  have  just  described  them, 
and  thus  a  clue  may  be  obtained  towards  the 
explanation  of  the  influence  of  geographical 
position  on  the  prevailing  colours  of  the  animal 
kingdom. 

Besides  the  colouring  matter,  another  kind  of 
product  is  secreted  between  the  corium  and 
cuticle,  viz.  the  shell :  this  presents  diffe- 
rent degrees  of  development  in  different  genera. 
M.  De  Blainville  in  France,  and  Leach, 
Broderip,  Gray,  and  Sowerby,  among  the 
able  naturalists  of  our  own  country,  maintain 
that  the  Argonaut  shell  is  not  the  product  of 
a  Cephalopod,  but  of  some  inferior  Mollusk, 
allied  to  the  Carinariae,  whose  shell  Linnaus 
indeed  placed  in  the  same  genus  with  the 
Argonauta,  in  consequence  of  the  close  rela- 
tionship subsisting  between  them,  both  in  form 
and  structure.  T?he  principal  grounds  for  this 
opinion  are  the  following.  The  Ocythoe  has 
no  muscular  or  other  attachment  to  the  Argo- 
naut shell.  When  captured,  and  placed  alive 
in  a  vessel  of  sea-water,  it  has  been  seen  vo- 
luntarily to  quit  the  shell,  and  in  one  instance 
without  manifesting  any  disposition  to  return 
to  it.  In  this  state,  viz.  without  its  shell, 
it  was  described  by  Ilafinesque  as  a  new  genus 
of  Cephalopod  under  the  name  of  Ocythoe, 
and  De  Blainville,  who  first  recognized  this 
genus  as  being  founded  on  an  animal  identical 
•with  the  Cephalopod  of  the  Argonaut,  or  the 
Nautilus  primus  of  the  ancients,  retained  the 
name  in  order  to  distinguish  the  supposed  parasite 
from  the  shell  which  it  had,  according  to  this 
theory,  adopted.  Agreeably  with  the  absence 
of  any  natural  connexion  between  the  Ocythoe 
and  the  shell  in  question,  is  the  fact  that  this 
animal  is  not  found  in  any  constant  or  regular 
position  in  the  shell.  In  most  examples  we 
have  found  the  funnel  and  ventral  aspect  of  the 
body  turned  towards  the  external  wall  of  theshell, 
as  in  the  figure  (fig-  206).  The  Cranchian  speci- 
men figured  by  Mr.  Sowerby  was  in  the  same 
position.  In  the  specimen  which  M.  De  Blain- 


ville* has  carefully  delineated  for  this  pur- 
pose, the  back  of  the  Ocythoe  is  next  the  invo- 
luted convexity  of  the  shell,  the  funnel"  is 
towards  the  opposite  expanded  concavity,  but 
turned  out  of  the  middle  line,  and  separated 
from  the  parietes  of  the  shell  by  the  retracted 
feet.  In  the  figure  which  illustrates  Brode- 
rip's  excellent  Memoir,t  the  animal  is  repre- 
sented with  the  funnel  next  the  involuted  crest 
of  the  shell.  In  another  specimen  in  the  unique 
collection  of  the  same  Naturalist,  the  Cephalo- 
pod is  retracted  on  a  mass  of  ova,  its  arms  hud- 
dled together,  and  its  funnel  projecting  from 
the  middle  of  one  side  of  the  shell;  on  the  op- 
posite side  numerous  suckers  are  seen  expand- 
ed and  applied  to  the  inner  surface  of  the  shell, 
demonstrative  of  the  abnormal  mode  of  its  ad- 
hesion to  that  body. 

Whatever  be  the  position  in  which  the 
Ocythoe  is  found,  the  whole  of  the  exterior 
surface  of  its  mantle  is  coloured  as  in  the 
naked  Cephalopods,  which  seems  to  indicate 
that  it  has  not  been  permanently  excluded  from 
light  by  an  opake  calcareous  covering,  such  as 
the  Argonauta  shell  must  have  formed  if  it 
had  been  applied  to  the  body  of  the  Ocythoe 
ab  ovo.  What  is  more  remarkable,  and  con- 
trary to  the  analogy  of  true  testacea,  is,  that 
there  is  little  or  no  correspondence  between  the 
disposition  of  the  colour  of  the  Ocythoe  and 
that  of  the  Argonaut  shell.  The  external  sur- 
face of  the  skin  of  the  Ocythoe  has  the  sarnie 
entire  epidermic  covering  as  in  the  naked 
Poulp,  yet  the  Argonaut  shell  is  furnished  with 
a  delicate  epidermis  in  its  natural  state. 

All  Mollusks  which  are  naturally  pro- 
vided with  external  shells  have  them  for  pro- 
tecting either  a  part  or  the  whole  of  the  body ; 
and  in  the  latter  case  the  interior  of  the  shell 
is  always  kept  clear,  that  the  animal  may  retire 
to  it  for  safety ;  but  this  retraction  into  the  hol- 
low of  the  shell  is  impossible  to  the  Ocythoe', 
at  least  in  those  numerous  cases  in  which  the 
shell  is  found  more  or  less  filled  with  masses 
of  ova.  Other  Cephalopods,  with  external 
shells,  indubitably  their  own,  as  the  Pearly 
Nautilus,  have  adequate  muscular  attachments ; 
and  it  may  reasonably  be  asked  does  the  Argo- 
naut afford  a  valid  exception  to  this  rule  1 

Such  an  exception  indeed  it  must  form  if 
the  shell  be  really  secreted,  as  the  Continuator 
of  Poli  asserts,  by  the  Cephalopod  inhabi- 
tant ;  and  not  only  in  this  particular,  but  in 
every  principle  which  has  been  established  in 
reference  to  the  relations  of  a  shell  to  the  body 
and  the  reciprocal  influences  affecting  them  in 
the  Molluscous  classes. 

The  naturalists  who  maintain  that  the  Ce- 
phalopod of  the  Argonaut  and  the  shell  are  parts 
of  one  and  the  same  animal,  insist  on  this  unde- 
niable fact,  that  from  the  time  of  Aristotle  to  the 
present  day  the  Argonaut  shell  has  never  been 
found  with  any  other  inhabitant  than  the 
Ocythoe  ;  and,  what  is  of  more  weight,  that  the 
Ocythoe  has  never  been  found  in  any  other  shell 
than  the  Argonauta.  Whereas  the  Hermit-Crab 

*  Malacologie,  torn.  ii.  p.  1, 
t  Zoological  Journal,  vol.  iv. 


CEPHALOPODA. 


545 


adopts  different  species  as  they  happen  to  fall  in 
his  way.  And  further,  that  the  different  species 
of  Argonauta,  as  the  A.  Argo,  A,  tuberculata, 
and  A.hians,  have  each  different  species  of  Ocy- 
t/iot.  We  may  add  that  the  light  fragile  tex- 
ture of  the  Argonauta  shell,  like  that  of  Ca- 
rinaria,  hespeaks  a  floating  oceanic  species, 
and  not  a  Mollusk  that  creeps  at  the  bottom, 
and  therefore  the  probability  is  less  that  its  real 
inhabitant  should  have  escaped  the  notice  of 
the  Naturalist,  supposing  the  Cephalopod  to 
be  a  parasite. 

In  the  posthumous  volume  of  Poli's  great 
work  on  the  Sicilian  Testacea,  it  is  stated  that 
that  naturalist  watched  the  daily  development 
of  the  ova  of  an  Ocythoe  contained  in  an  Ar- 
gonaut shell,  and  that,  by  means  of  the  micro- 
scope, he  detected  the  rudiment  of  the  shell 
in  the  embryo  :  the  completion  of  the  experi- 
ment was,  however,  accidentally  interrupted  ; 
and  the  figure  which  the  editor  Delia  Chiaje 
has  published  of  the  ovum,  which  it  was 
hoped  would  have  determined  the  question, 
seems  to  shew  the  yolk  appended  to  the  embryo 
instead  of  the  shell. 

Mr.  Gray,*  on  the  other  hand,  has  recently 
stated  that  the  nucleus  of  the  Argonaut  shell, 
or  that  part  which,  from  analogy,  must  have 
been  formed  in  the  egg,  is  too  large  to  have 
been  formed  in  the  egg  of  the  Ocythoe.  The 
arguments  drawn  from  the  microscopical  exa- 
mination of  the  ova  of  the  Ocythoe  before  the 
commencement  of  the  development  of  the 
embryo,  are  obviously  inconclusive;  since, 
whatever  the  subsequent  products  of  the  egg 
might  be,  at  this  period  only  the  granular 
and  oily  particles  of  the  vitelline  nidus  could 
be  expected  to  be  seen. 

With  respect  to  another  argument  against 
the  legitimate  title  of  the  Ocythoe'  to  the  shell, 
founded  on  the  supposed  uniform  occurrence 
of  a  deposition  of  eggs  in  the  same  shell,  we 
can  adduce  three  exceptions  in  which  the 
Argonaut  shell  was  exclusively  occupied  by 
the  Cephalopod ;  these  specimens  were  taken 
along  with  several  others,  by  Captain  P.  P. 
King,  R.N.,  from  the  stomach  of  a  Dolphin, 
caught  upwards  of  six  hundred  leagues  from 
land,  and  were  kindly  presented  to  us  by  that 
gentleman.  In  these  examples,  as  in  others, 
we  were  struck  with  the  exact  correspondence 
between  the  size  of  the  shells  and  that  of  their 
inhabitants,  every  trifling  difference  in  the 
bulk  of  the  latter  being  accompanied  with 
proportional  differences  in  the  shells  which 
they  occupied.  The  consideration  of  all  these 
circumstances  has  prevented  a  satisfactory  con- 
clusion being  formed  with  respect  to  this  long- 
agitated  and  nicely-balanced  question,  and  we 
are  compelled  to  repeat  after  the  Stagyrite, 
Si  y£VE0-6»?  nal  <njva,v£hs-tcas  TOU  oyffatiov  aHpiftu 

ov-mu  Zirr*i.-\-  Observation  of  the  development 
of  the  Ocythoe'  until  the  period  when  it  is  ex- 
cluded from  the  egg,  would  decide  the  point. 

*  See  Proceedings  of  the  Zoological  Society, 
September,  1834. 

•f  "  But  as  touching  the  generation  and  growth  of 
the  shell  nothing  is  as  yet  exactly  determined." — 
Hist,  Anim.  lib.  ix. 


But  this  must  be  done  satisfactorily,  and  with 
the  requisite  knowledge,  care,  and  good  faith 
on  the  part  of  the  observer. 

Before,  however,  quitting  this  subject,  we 
will  mention  one  example  of  a  naked  Ce- 
phalopod, nearly  allied  to  Ocythoe,  having 
manifested  a  parasitic  propensity  similar  to 
that  which  is  laid  to  the  charge  of  that  genus. 
A  medical  gentleman,  (Dr.  Moffat,  of  the 
Hon.  East  India  Company's  Ship,  Flora,)  who 
had  collected  objects  in  Natural  History  in 
the  East  Indies,  amongst  other  specimens 
brought  home  an  Octopus,  which  was  caught  in 
the  Madras  roads  in  his  presence,  by  means 
of  a  baited  hook  and  line,  and,  when  drawn 
out  of  the  water,  was  found  to  have  its  ven- 
tricose  body  firmly  imbedded  in  a  ghee-bowl, 
(one  of  the  small  round  pots  in  which  the  fluid 
butter  is  brought  on  board  ship,)  which  had  been 
thrown  overboard.  The  Doctor  disengaged  the 
Cephalopod  from  the  bowl  before  placing  it  in 
spirits,  and  when  we  related  to  him  the  interest 
which  the  fact  possessed  in  consequence  of  the 
problematic  nature  of  the  Argonaut  shell,  of 
which  he  was  not  before  aware,  he  regretted 
much  that  he  had  not  preserved  the  Octopus 
in  the  singular  domicile  which  it  had  chosen. 
Another  instance  of  the  parasitic  appropriation 
of  a  dwelling-place  by  a  Poulp  is  related  by 
M.  Desjardins,  in  the  Report  of  the  Natural 
History  Society  of  the  Mauritius  ;  he  found  an 
Octopus  Arenarius  in  the  shell  of  a  Dolium. 

The  parasitic  occupation  of  shells  by  the 
Octopi  for  the  purpose  of  depositing  the  ova  in 
them  was  not  unknown  to  Aristotle.  K*l 

aTTOTi'xTEt  9  /UEV  TroXuTTOtif  Ei(  raj  &aXetyAttf  >j  t\<;  HipafAM 
n  n  o'xx*  aoTxev  6'/*o;ov,  &c.  "  And  the  Polypus 
oviposits  in  cavities  or  in  shells,  or  some  such 
hollow  places."* 

To  return  to  the  shells  of  the  Dibranchiate 
Cephalopods;  these,  then,  with  the  doubtful 
exception  of  the  Ocythoe,  are  always  internal, 
and  either  camerated  and  siphoniferous,  or 
laminated  and  more  or  less  rudimental, 
and  concealed  within  the  substance  of  the 
mantle. 

In  Octopus  and  Eledone  the  traces  exist  in 
the  form  of  two  small  amber- coloured  styli- 
form  bodies,  lodged  loosely  in  capsules,  (im- 
bedded in  the  sides  of  the  mantle,)  and  ex- 
tending downwards  from  the  insertion  of  the 
shell  muscles,  close  to  the  base  of  the  bran- 
chiae. When  the  capsules  are  laid  open,  the 
styles  frequently  fall  out  in  pieces,  being  of  a 
friable  texture.  In  the  Octopus  the  styles  are 
straight  and  elliptical ;  in  Eledone  they  are 
largest  at  their  upper  extremities,  and  become 
filiform  as  they  pass  in  a  curved  direction 
downwards. 

In  all  the  Decapoda  in  which  the  shell  is 
rudimental,  it  is  represented  by  a  single  piece 
lodged  in  the  middle  line  of  the  dorsal  region 
of  the  mantle.  It  is  of  a  horny  texture  in  all 
the  genera  except  the  Sepia,  and  has  generally 
more  or  less  the  form  of  a  feather,  as  in  the 
Calamary  (fig.  228),  or  of  a  straight  three- 
edged  sword. 

*  Hist.  Anim.  v.  c.  16. 


546 


CEPHALOPODA. 


According  lo  Aristotle  the  hard  dorsal  body 
of  the  Cuttle-fish  was  called  by  the  Greeks 
1  sepion,'  that  of  the  Calamaries  *  xiphos.'* 
In  Sepiola  and  Rossia  the  gladius  does  not 
reach  half-way  down  the  back,  beginning  at 
the  anterior  margin  of  the  mantle,  which  in 
the  latter  genus  is  free.  In  Loligopsis,  Cran- 
chia,  Onycoteut/iis,  and  Loligo,  it  extends 
the  whole  length  of  the  posterior  part  of  the 
mantle.  In  Sepioteuthis  it  rivals  in  breadth 
the  Sepium  or  Cuttle-bone,  but  is  horny  and 
elastic,  as  in  the  Calamary.  In  the  latter  the 
gladius  is  multiplied  by  age,  and  several  are 
found  packed  closely  one  behind  another  in 
old  specimens. 

Fig.  229. 


Gladius  of  the 
Calamary. 


Rudimental  Shell  of  the 
Cuttle-fish. 


The  Sepium  or  Cuttle-bone  (fig.  229)  is  a 
well-known  substance,  and  formerly  figured  in 
the  Materia  Medica  as  an  antacid.  It  is  a 
light  cellular  calcareous  body,  of  a  peculiar 
form  and  structure  ;  and,  as  it  is  confined  ex- 
clusively to  the  genus  Sepia,  its  presence  alone 
serves  to  characterise  that  section  of  Cepha- 
lopods.  Its  form  is  an  elongated  oval,  de- 
pressed, convex  on  the  dorsal  surface,  partly 
convex  and  partly  concave  on  the  opposite 
side:  it  terminates  posteriorly  in  a  very  thin, 


*  "  TB  /u§v  ovV  o-r,in'itt,  x.al  -rn  ttvi  xa   tm  rt 

IvW?  £fl    Ttt  <TTEp£«  EV    Tfl5  TTpetVei  TOV  r&flCtTQG,     3.  Xtt- 

Xotlm  TO  /U.EV  sri-Triov,  T»  Si  £/<f>o$.      Sub     dorso    firma 

Ears  Sepiae  Loligini  ac  Lolio  continetur  ;  i\\ius  sepium, 
orum  gladuim  vocant-  —  Hist.  Animal.,  lib.  iv.,  c.  1. 
12mo.     Ed.  Schneider. 


dilated,  aliform  margin  (a,  a),  partly  calca- 
reous and  partly  horny,  which  becomes  nar- 
rower as  it  advances  forwards,  and  is  gradually 
lost  in  the  sides  of  the  shell.  As  this  margin 
is  inclined  towards  the  ventral  aspect,  it  pro- 
duces at  the  posterior  and  ventral  side  of  the 
shell  a  wide  and  shallow  concavity,  comparable 
to  the  chamber  of  the  Nautilus  shell  which 
protects  the  body  of  that  species  :  if  the  free 
margin  of  the  sepium  were  in  like  manner 
produced  beyond  the  previously  deposited 
layers,  it  would  advance  from  the  posterior  and 
lateral  aspects  of  the  animal,  and  cover  the 
ventral  surface,  as  in  the  Nautilus,  leaving  the 
convexity  produced  by  the  chambered  portion 
projecting  into  the  back.  The  thickened  part 
of  the  sepium  (6)  which  retains  that  situation, 
is  in  fact  composed  of  a  series  of  thin  parallel 
calcareous  plates,  successively  deposited  and 
extending  obliquely  forwards  from  the  ventral 
to  the  dorsal  surface  :  the  last  formed  plate  is 
the  most  internal  and  the  broadest,  but  not  the 
longest  also,  as  in  the  Nautilus ;  its  develop- 
ment being  limited  to  the  anterior  part  of  the 
shell,  so  that  the  previously  deposited  layers 
appear  successively  behind  it  forming  irregular 
sinuous  transverse  striae  (c).  The  intervals  of 
the  plates  are  occupied  by  crystalline  fibres, 
passing  perpendicularly  from  one  layer  to  the 
other :  A  is  a  magnified  view  of  this  structure. 
At  the  posterior  part  of  the  sepium,  a  little 
anterior  to  the  thin  margin,  a  pointed  hooked 
process  projects  backwards :  this  differs  m  size 
and  shape  in  different  species  of  Sepia;  but  it  is 
always  characteristic  of  the  peculiar  production 
which  has  been  described,  and  has  served  to 
identify  some  doubtful  fossils. 

As  our  present  observations  are  limited  to 
the  recent  species  of  Cephalopoda,  we  pass 
over  the  Belemnites,  which  are  fossil  internal 
shells  of  extinct  animals  of  this  order,  to  speak 
of  that  of  the  Spirula.  This  is  a  small  recent 
Cephalopod,  respecting  the  precise  form  and 
organization  of  which  nothing  is  yet  satis- 
factorily known.  The  only  entire  specimen 
which  has  been  brought  to  Europe  was  taken 
by  Peron,  a  French  Naturalist,  as  it  floated 
dead  in  the  Tropical  Ocean,  between  the  Mol- 
luccas  and  the  Isle  of  France ;  it  has  been  de- 
scribed and  figured  by  Roissy,  Peron,  and 
Lamarck  ;  but  both  the  figures  and  descrip- 
tions of  these  authors  differ,  and  the  specimen 
now  no  longer  exists  to  determine  the  accuracy 
of  either  of  the  accounts.  All  agree,  how- 
ever, in  stating  that  part  of  the  shell  was 
concealed  within  the  body  of  the  animal ;  and 
this  fact  is  confirmed  by  a  mutilated  specimen 
in  our  own  possession,  and  by  one  in  a  similar 
condition  in  the  British  Museum. 

The  shell  of  the  Spirula  (jig.  230)  is  about 
an  inch  in  diameter, 


symmetrical,  con- 
voluted on  one 
plane,  with  the 
whorls  disjoined  : 
it  is  composed  of  a 
succession  of  small 
regularly  formed 


Fig.  230. 


Shell  of  the  Spirula. 


chambers,  separated  by  partitions  («,  «),  which 


CEPHALOPODA. 


547 


are  concave  towards  the  outlet  of  the  shell, 
and  are  perforated  by  a  siphon  (6),  the  mem- 
branous tube  of  which  is  protected  by  a  series 
of  funnel-shaped  calcareous  sheaths  (c),  which 
are  continued  from  the  hole  of  one  septum 
into  that  of  the  next,  throughout  the  shell. 
The  shell  is  white,  lined  with  a  nacrous  layer 
within,  and  partially  covered  by  a  straw-coloured 
epidermis  without.  The  organization  of  the 
Spirula  may  be  expected  to  be  in  some  respects 
intermediate  to  the  Nautilus  and  Sepia,  and  an 
opportunity  of  investigating  its  internal  struc- 
ture is  therefore  highly  desirable.  According 
to  Lamarck  the  animal  is  a  Cephalopod  with 
eight  feet  and  two  tentacles,  like  a  Cuttle-fish, 
all  provided  with  suckers ;  the  body  shaped 
like  a  purse  and  terminated  behind  by  two 
lobes. 

Although  the  siphoniferous  shells  are  not 
confined  to  the  Tetrabranchiate  Order,  yet  it  is 
in  this  division,  as  in  the  Pearly  Nautilus  for 
example,  that  we  find  this  singular  testaceous 
production  to  have  arrived  at  the  maximum  of 
its  development :  it  is  covered  by  an  epidermis, 
and,  in  the  living  animal,  is  also  probably 
partially  overlapped  by  a  reflected  portion  of 
the  thin  and  extensible  mantle ;  but  no  part  of 
it  is  buried  in  the  substance  of  the  animal, 
whose  entire  body,  on  the  contrary,  is  inclosed 
in  the  last  large  expanded  chamber.  The  re- 
lative position  of  the  soft  parts  to  this  cham- 
ber we  had  not  the  means  of  determining  from 
the  specimen  dissected  by  us,  as  this  had  been 
removed  from  its  shell  by  Mr.  Bennett,  its 
fortunate  captor,  before  it  was  placed  in  spirits. 
According  to  this  able  naturalist's  statement, 
however,  the  ventral  surface  of  the  body  and 
funnel  was  applied  to  the  concavity  of  the 
outer  expanded  wall  of  the  chamber;  and  the 
concavity  behind  the  cephalic  disk  was  adapted 
to  the  involuted  convexity  of  the  shell,  and 
abutted  against  the  ridge  which  rises  from  that 
part.*  The  camerated  portion  of  the  shell, 
according  to  Mr.  Bennett,  contained  water  or 
a  liquid ;  but  the  size,  condition,  and  con- 
tents of  the  membranous  tube  were  not  ob- 
served by  him.  The  external  form  of  the  soft 
parts  supported  Mr.  Bennett's  account  of  their 
relative  position  to  the  shell;  but  some  cir- 
cumstances appeared  to  militate  against  the 
fluid  nature  of  the  contents  of  the  deserted 
chambers.  In  the  description  of  this  spe- 
cimen, we  accordingly  stated  our  belief  that 
the  chambers  are  naturally  filled  by  a  gaseous 
exhalation  or  secretion  of  the  animal,  and  that 
the  liquid  is  contained  in  the  dilatable  siphon 
which  is  extended  from  the  posterior  part  of 
the  animal's  body,  and  passes  through  the 
central  apertures  of  the  different  septa  of  the 
shell.  From  the  communication  which  this 
siphon  has  with  the  pericardial  cavity,  it  can  be 
influenced,  as  to  the  quantity  of  fluid  which  it 

*  M.  De  Blainville,  in  a  learned  Memoir  on  the 
Structure  of  the  Shells  of  Spirula  and  Nautilus, 
states  his  opinion  that  the  true  position  of  the  ani- 
mul  of  the  latter  shell  is  the  reverse  of  that  de- 
scribed above  :  this  opinion  has  been  adopted  by 
some  Naturalists  of  this  country,  but  the  analogies 
by  which  it  is  endeavoured  to  be  supported  are  too 
remote  and  vague  to  enforce  conviction. 


contains,  by  the  actions  of  the  Nautilus  itself.  A 
pneumatic  and  hydraulic  apparatus  for  effecting 
the  rising  and  sinking  of  the  shell  and  its  in- 
habitant is  thus  established,  and  Dr.  Hooke's 
ingenious  conjecture  of  the  use  of  the  camerated 
part  of  the  shell  is  confirmed;*  but  the  relative 
positions  of  the  gas  and  water  would,  accord- 
ing to  the  above  opinion,  be  the  reverse  of  what 
Parkinsonf  supposed  them  to  be.  The  full 
development  of  the  theory  of  chambered  shells, 
considered  as  hydrostatic  instruments,  is,  how- 
ever, in  abler  hands  than  ours;  and  the  reader 
will  be  gratified  to  learn  that  it  forms  the  sub- 
ject of  a  portion  of  the  forthcoming  Bridge- 
water  Treatise  by  Dr.  Buckland. 

NERVOUS  SYSTEM. — In  tracing  the  develop- 
ment of  the  Nervous  System  through  the 
Heterogangliate  or  Molluscous  type  of  Orga- 
nization, we  find  in  the  Gasteropodous  genera 
which  approach  nearest  to  the  Cephalopodous 
or  highest  division,  that  the  ganglions  which 
are  concentrated  about  the  head,  are  arranged 
in  three  groups  :  one,  which  is  supraresopha- 
geal,  supplies  the  sentient  organs,  as  the  eyes 
and  feelers ;  a  second,  which  is  subcesophageal 
and  anterior,  supplies  the  buccal  apparatus ; 
a  third,  which  is  subcesophageal  and  pos- 
terior, is  the  centre  from  which  the  sensitive, 
motive,  and  plastic  nerves  of  the  trunk  ori- 
ginate. The  anterior  or  buccal  ganglions  are 
united  together,  and  to  the  cerebral  ganglions, 
forming  a  nervous  collar  around  the  oesophagus ; 
a  similar  collar  is  formed  by  the  corresponding 
intercommunicating  chords  of  the  posterior 
subcesophageal  ganglia. 

In  the  Cephalopods  the  nervous  system  is 
disposed  on  the  same  general  plan,  but  the 
nervous  substance  is  accumulated  in  a  greater 
degree  at  the  different  centres  of  radiation, 
according  to  the  superior  development  of  the 
parts  that  are  to  be  supplied  therefrom. 

In  the  Tetrabranchiate  Order  the  principal 
parts  superadded  to  the  structure  which  we 
observe  in  the  Gasteropodous  Mollusk  are  those 
locomotive  and  prehensile  organs  which  sur- 
round the  buccal  apparatus;  and  the  chief 
modification  of  the  nervous  system  is  therefore 
seen  in  the  enlargement  of  the  oral  ganglia 
and  collar,  and  their  close  approximation  to 
the  cerebral  ganglion.  This  part  is  compara- 
tively little  advanced,  since  the  organs  of 
sense  which  it  immediately  supplies,  retain 
the  same  simple  structure  as  in  the  inferior 
class  of  Mollusks,  and  are  only  augmented 
in  bulk.  The  brain  therefore  is  represented 
by  a  thick  round  tranversely  extended  chord 
(1,^/zg.  231),  communicating  at  its  extremi- 
ties with  the  anterior  and  posterior  cesopha- 
geal  collars  (3,  4),  and  with  the  small 
optic  ganglions  (2,  2),  which  supply  the  sim- 
ple pedunculated  eyes.  Four  small  pairs  of 
nerves  (5)  also  pass  from  the  supracesophageal 
band  to  the  fleshy  mass  supporting  the  man- 
dibles. The  cranial  partilage  seems  in  the 
Nautilus  to  be  principally  developed  with  re- 
ference to  the  strong  muscular  masses  to  which 

*  Philosophical  Experiments  and  Observations, 
p.  307. 

t  Organic  Remains,  vol.  iii.  p    102. 


584 


CEPHALOPODA, 

Fig.  231. 


Nervous  System  of  the  Pearly  Nautilus. 


it  affords  a  fixed  point  of  attachment,  and  is 
not  extended  upwards  so  as  to  inclose  the 
brain  :  this  part  is  defended  by  a  strong  mem- 
brane which  loosely  surrounds  it ;  but  the  ex- 
tremities of  the  transverse  band,  the  optic  gan- 
glions, and  the  anterior  resophageal  collars  rest 
in  grooves  of  the  cranial  cartilage. 

The  nerves  which  arise  from  the  anterior 
collar  are  very  numerous  :  the  larger  branches 
(6,  6)  enter  respectively  the  roots  of  the  ten- 
tacles which  are  lodged  in  the  digital  pro- 
cesses :  the  ophthalmic  tentacles  are  also  sup- 
plied from  this  source  (5*);  no  lateral  con- 
necting filaments  are  found  between  these 
nerves,  corresponding  to  those  which  associate 
the  corresponding  nerves  of  the  Poulp  for  the 
simultaneous  action  of  the  parts  they  supply. 
Below  the  digital  nerves  small  nerves  are 
given  off  (12),  which  enter  the  external  labial 
processes,  and  penetrate  in  a  similar  manner 
the  roots  of  the  tentacles  which  are  there 


lodged.  The  internal  labial  processes  are, 
however,  supplied  in  a  different  manner :  a 
larger  nerve  (7,  7)  comes  off  on  each  side  near 
the  ventral  extremity  of  the  ganglion,  and  after 
a  course  of  half  an  inch  swells  out  into  a 
flattened  ganglion*  (8,  8),  from  which  nu- 
merous filaments  (9,  9)  extend  into  the  sub- 
stance of  the  process,  and  are  continued  into 
the  tentacles  as  in  the  preceding  case  ;  a  larger 
twig  (10)  inclines  inwards  and  distributes  fila- 
ments to  the  olfactory  laminae.  The  infundi- 
bular nerves  (11)  come  off  near  the  lower  part 
of  the  anterior  collar. 

From  the  ganglions  composing  the  posterior 
collar  (4,  4)  arise  numerous  nerves  of  a  flat- 
tened form,  (13,  13,)  which  pass  in  a  radiated 
manner  to  the  inner  sides  of  the  shell-muscles 

*  These  ganglions  I  believe,  from  subsequent 
examination,  to  have  been  also  connected  with  a 
nervous  twig  from  the  fleshy  mass  of  the  mouth, 
derived  from  the  supra-oesophageal  ganglion. 


CEPHALOPODA. 


549 


which  they  perforate,  but  there  are  no  columns 
prolonged  backwards  from  the  lateral  parts  of 
the  brain  to  form  pallial  ganglia  as  in  the 
higher  Cephalopods ;  the  structure  and  func- 
tions of  the  cloak  to  which  these  ganglia  are 
subservient,  not  being  enjoyed  by  the  shell- 
clad  Nautilus.  The  nerves  corresponding  to 
the  large  visceral  nerves  of  the  Dibranchiates 
are,  however,  proportionally  developed;  for  in 
the  organs  of  plastic  life  the  Nautilus  is  upon 
an  equality  with  its  naked  congeners.  These 
nerves,  which  combine  the  functions  of  the 
sympathetic  and  par  vaguin,  consist  of  a  large 
pair  derived  from  the  lower  part  of  the  pos- 
terior ossophageal  collar,  and  extending  back- 
wards on  each  side  of  the  vena  cava ;  and  of 
smaller  twigs  (17)  coming  off  between  the 
origins  of  the  preceding  nerves,  and  forming  a 
plexus  upon  the  parietes  of  the  vein.  The 
larger  chords  swell  into  ganglions  at  the  termi- 
nation of  the  vena  cava,  (16, 16,)  and  send  off 
ramifications  to  the  branchiae,  (15,  15,)  the 
contents  of  the  pericardium,  and  the  viscera  of 
digestion  and  generation. 

In  the  Dibranchiate  Cephalopods  which 
possess  instruments  for  varied  and  active  loco- 
motion, where  the  visual  organ  is  of  large  size, 
and  attains  a  complexity  of  structure  equal  to 
that  of  the  Vertebrate  animals,  where  a  distinct 
acoustic  organ  is  developed,  and  where  the 
whole  surface  of  the  body  is  the  seat  of  sensi- 

Fig.  232. 


Nervous  system  of  the  Cuttle. 


bility,  the  centre  of  nervous  impression  and 
volition  is  proportionally  developed,  and  exhi- 
bits the  highest  conditions  which  the  brain  pre- 
sents in  the  Invertebrate  series  of  animals. 

Except  in  some  of  the  smaller  species,  as 
the  Sepiola,  in  which  the  surrounding  sub- 
stance still  retains  the  consistency  of  a  mem- 
brane, the  brain,  together  with  the  anterior 
and  posterior  cesophageal  collars,  is  entirely 
surrounded  by  a  thick  cartilage.  The  portion 
of  oesophagus  which  is  thus  enclosed  is  sepa- 
rated from  the  surrounding  medullary  matter 
by  a  thin  layer  of  softer  substance.  The  cere- 
bral cavity  is  larger  than  the  brain  itself,  and 
the  intervening  space  is  filled  with  a  gelatinous 
fluid.  In  the  Cuttle-fish  the  supra-resophageal 
mass  is  transversely  shortened,  as  compared 
with  the  Nautilus,  and  supports  a  smooth, 
rounded,  heart-shaped  medullary  mass,  slightly 
divided  into  two  lateral  lobes  by  a  mesial  lon- 
gitudinal furrow  (1,  fig.  232);  from  the  lower 
and  lateral  parts  of  this  body  proceed  the  broad 
bands  of  cerebral  substance  which  afterwards 
dilate  into  the  large  reniform  optic  ganglions 
(2,  2);  upon  each  of  these  bands  is  placed  a 
small  spherical  medullary  body  ( k,  /c).  These 
bodies,  which  we  first  discovered  in  the  Sepia, 
we  have  since  ascertained  to  exist  in  Loligo. 

From  the  anterior  apices  of  the  cerebral 
lobes  small  nerves  are  continued,  which  almost 
immediately  dilate  into  a  round  flattened  gan- 
glion (a,  Jig.  233) ;  this  is  closely 
applied  to  the  back  part  of  the  fleshy 
mass  of  the  mouth  above  the  pharynx ; 
it  sends  off  nerves  to  the  oral  appa- 
ratus (i,  i,  fig.  233),  and  two  fila- 
ments descend  and  form  a  pair  of 
small  closely  approximated  ganglions 
(8,  8,  Jig.  232)  below  the  mouth, 
analogous  to  the  labial  ganglions  of 
the  Nautilus. 

From  the  inferior,  lateral,  and  an- 
terior parts  of  the  brain  two  large 
chords  (k,  Jig.  233)  descend,  and 
unite  and  dilate  below  the  oesopha- 
gus to  form  the  anterior  subaso- 
phageal  ganglion,  or  pes  anserinus  of 
Cuvier,  from  which  the  nerves  of  the 
feet  and  tentacles  arise.  Two  still 
larger  bands  (I,  fig.  233)  descend 
from  the  brain  behind  the  preceding 
to  form,  by  a  similar  enlargement  and 
union,  the  posterior  oesophageal  gan- 
glionic  collar.  From  a  comparison 
of  these  with  the  corresponding  gan- 
glions of  the  Nautilus,  it  will  be  seen 
that  by  their  approximation  in  the 
transverse  direction  the  distinction 
of  the  ganglions  at  the  lower  part 
of  the  collar  is  lost;  and  a  corre- 
sponding approximation  in  the  antero- 
posterior  direction,  being  accompa- 
nied by  an  additional  accumulation 
of  nervous  substance,  has  produced 
a  blending  together  of  the  four  gan- 
glions into  one  large  continuous  sub- 
O3sophageal  mass.  The  portions  of 
this  mass  corresponding  to  the  four 
ganglions  and  double  cesophageal 


550 


CEPHALOPODA. 


collar  of  the  Nautilus,  are  notwithstanding 
indicated  in  a  manner  not  to  be  mistaken, 
by  the  origins  of  the  nerves  which  it  sends 
off,  and  by  the  chords  which  bring  it  into 
communication  with  the  cerebral  mass  above. 

We  shall  now  briefly  mention  the  points  in 
which  the  brain  in  other  Dibranchiata  differs 
from  what  we  have  described,  after  careful 
examination  of  this  part  in  the  Cuttle-fish.  In 
the  Poulp,  the  brain  or  supra-cesophageal  mass 
is  divided,  according  to  Cuvier,  into  two  parts, 
an  anterior  (a,  Jig.  233),  which  is  of  a  flatter 
and  squarer  figure  and  of  a  whiter  colour, 
compared  by  Cuvier  to  the  cerebrum,  but 
which  seems  to  be  the  pharyngeal  ganglion 
more  closely  approximated  to  the  brain  than 
in  the  Sepia :  and  a  posterior  globular  mass 
( b),  of  a  grey  colour,  which  he  compares  to 
the  cerebellum  ;  the  optic  nerves  (c)  are  much 
smaller  than  in  the  Cuttle-fish,  and  do  not 
support  the  small  spherical  bodies  which  exist 
in  the  Cuttlefish  and  Calamary. 

Fig.  233. 


V 


Brain  and  nerves  of  the  Octopus  vulgaris. 

The  brain  of  the  Argonauta  does  not  present 
a  rounded  form  above,  but  when  seen  from  this 
aspect,  is  composed,  as  in  the  Octopus,  of  an 
-anterior  white  oblong  band,  flattened  trans- 
versely, and  of  a  posterior  raised  convex  semi- 
lunar  mass,  which  terminates  behind  in  a  semi- 
lunar  border,  the  extremities  of  which  are  con- 
tinued directly  to  form  the  posterior  collar  of 
the  asophagus. 

The  nerves  of  the  arms  proceed  from  the 
anterior  and  inferior  subcesophageal  ganglions 
(dyfig.  233),  corresponding  in  number  to  the 


parts  they  supply,  viz.  eight  in  the  Octopoda* 
and  ten  in  the  Decapoda.  But,  according  to 
Rathke",  the  Loligopsis  offers  an  exception,  the 
nerves  of  each  lateral  series  of  arms  being  con- 
tinued for  a  short  distance  from  the  brain  as  a 
single  pair.  In  the  Poulp,  the  eight  nerves 
(e,  e,fg.  233)  glide  along  the  inner  surface  of 
the  basis  of  the  feet,  which  they  penetrate  re- 
spectively, running  with  the  great  artery  in 
their  substance,  and  forming,  as  Cuvier  has 
described,  a  series  of  closely  approximated 
ganglions,  corresponding  to  each  pair  of  suck- 
ers, and  sending  off  radiated  filaments.  In  the 
Genus  Eledone,  where  the  arms  are  narrower, 
and  the  suckers  are  arranged  in  a  single  series, 
the  ganglia  are  relatively  smaller. 

In  the  peduncles  of  the  Decapoda  the  nerves 
are  continued  of  a  simple  structure  as  far  as  the 
acetabuliferous  extremities,  where  they  become 
enlarged  and  gangliated. 

Before  forming  the  ganglionic  enlargements 
in  the  ordinary  arms,  each  brachial  nerve  gives 
off  two  large  chords,  one  to  each  side,  which 
traverse  the  fleshy  substance  of  the  base  of  the 
feet  to  join  the  two  corresponding  branches  of 
the  contiguous  arms  ;  the  eight  nerves  are  thus 
associated  by  a  nervous  circle  (f,f,  jig.  233), 
which  subdivides  into  two,  and  forms  a  small 
loop  at  each  chord. 

Behind  the  origin  of  the  brachial  nerves,  the 
large  infundibular  nerves,  a  single  pair  (g, 
Jig.  233),  are  given  off.  The  small  acoustic 
nerves  (h)  arise  below  and  behind  the 
nerves  of  the  funnel,  from  the  nervous  sub- 
stance that  effects,  as  it  were,  the  junction  of  the 
two  oesophageal  collars  below.  Next  arise  the 
large  visceral  nerves  (14,^.232,233),  which, 
after  distributing  filaments  to  the  muscles  of 
the  neck,  descend  parallel  and  close  to  one 
another  behind  the  vena  cava,  give  off  from 
their  inner  sides  the  small  filaments  which  con- 
stitute the  plexus  upon  the  vein;  they  then 
diverge  from  each  other  towards  the  root  of 
each  gill,  where  they  divide  into  three  princi- 
pal branches :  one  of  these  dilates  into  an 
elongated  ganglion  (c,Jig.  232),  and  enters  the 
fleshy  stem  of  the  branchia;  the  second  de- 
scends to  the  bottom  of  the  sac ;  the  third 
passes  to  the  middle  heart.  The  plexus  pre- 
viously formed  upon  the  vena  cava  receives 
additional  filaments  from  the  two  latter  bran- 
ches ;  and  a  large  sympathetic  ganglion  is 
formed,  which  is  attached  to  the  parietes  of  the 
stomach,  near  the  pyloric  orifice.* 

The  most  important  and  interesting  nerves  are 
the  two  largeones,(13,13,/gs.232,  233,)which 
arise  from  the  posterior  and  lateral  surface  of 
the  subcesophageal  mass,  and  extend  outwards, 
downwards,  and  backwards,  perforating  the 
shell  muscles,  and  forming  upon  the  inner 
parietes  of  the  mantle  the  large  stellated  gan- 
glion ( d,  d,Jig.  232),  from  which  the  nerves  of 
the  mantle  are  derived.  In  the  Octopoda  the 

*  See  Brandt  Medicin.  Zoolog.  a.  a.  O.  S.  p.  309, 
tab.  xxxii.  fig.  23,  who  first  described  this  ganglion 
in  the  Sepia,  and  Jacob's  figures  of  the  Anatomy  of 
the  Octopus  Vulgaris,  pi.  xv.  fig.  7  ;  pi.  xiii.  figs. 
2  &  3,  in  Fertissac's  Monograph  on  Cephalopods, 
fol. 


CEPHALOPODA. 


551 


nerve  terminates  in  this  ganglion,  (v,  v,  fig. 
226,)  from  which  about  twenty  branches  radiate 
to  the  mantle ;  but  in  the  Decapoda,  in  which 
lateral  fins  are  superadded  to  the  trunk,  it  pre- 
viously divides  into  two  large  branches.  Of 
these  the  external  alone  produces  the  ganglion 
from  which  the  sensitive  nerves  are  distributed 
in  a  radiated  manner,  as  in  the  Poulp;  the  other 
division  (e,fg.  232),  after  having  been  joined 
by  a  branch  (f)  from  the  ganglion,  pierces  the 
fleshy  substance  of  the  mantle,  and  ends  in  a 
diverging  series  of  twigs  appropriated  to  the 
muscles  of  the  fin  (g).  In  proportion  as  the 
trunk  of  the  Cephalopod  is  elongated,  these 
branches  become  more  parallel  in  their  course, 
and  dorsal  in  their  position. 

The  anterior  part  of  the  mantle  is  supplied 
by  small  nerves,  having  a  distinct  origin  from 
the  posterior  subrcsophageal  mass,  above  the 
great  moto-sensitive  chords. 

With  respect  to  the  parts  of  the  central  axis 
of  the  nervous  system  of  the  Vertebrata  which 
are  represented  by  the  structures  above  de- 
scribed, we  may  reasonably  infer  from  the  fact 
that  the  supracesophageal  mass  in  the  Dibran- 
chiate  Cephalopods,  especially  the  posterior 
division,  is  principally  in  communication  with, 
and  owes  its  superior  development  chiefly  in 
relation  to  the  complex  organs  of  vision,  that  it 
is  analogous  to  the  optic  lobes  or  bigeminal 
bodies.  For  if  it  be  regarded,  as  Cuvier  sup- 
poses, as  the  cerebellum  of  the  vertebrate  brain, 
we  have  then  to  reconcile  the  anomaly  of  this 
part  being  the  seat  of  origin  of  the  optic  nerves. 
The  constancy,  again,  of  the  optic  lobes  in  the 
vertebrate  series,  and  their  priority  of  develop- 
ment to  the  cerebellum,  leads  naturally  to  the 
expectation  that  these  would  form  part  of  such 
a  brain  as  the  highest  invertebrate  animal  is 
endowed  with.  The  smaller  portion  of  the 
brain  of  the  Poulp  anterior  to  the  optic  lobes 
appears  to  represent  an  olfactory  lobe.  With 
respect  to  the  inferior  cesophageal  mass,  as  it 
gives  origin  to  the  auditory  and  respiratory 
nerves,  and  those  two  large  moto-sensitive  co- 
lumns, which  evidently  represent,  by  their 
structure  and  position,  the  spinal  cord  of  the 
Vertebrata,  we  consider  it  as  fulfilling  the 
function  of  the  medulla  oblongata,  and  to  be 
the  part  of  the  nervous  centre  which  is  most 
intimately  connected  with  the  vital  energies  of 
the  animal.* 

ORGANS  OF  SENSE. — The  Cephalopodous 
class  is  the  only  one  in  the  Invertebrate  series 
in  which  distinct  organs  of  sight,  hearing,  smell, 
and  taste,  have  been  detected,  although  the  en- 
joyment of  these  senses  is  evidently  byno  means 
limited  to  this  class.  Considerable  differences, 
however,  present  themselves  in  the  relative 
complexity,  and  even  as  to  the  existence  of 
the  different  Organs  of  Sense  in  the  two  orders 
of  Cephalopods :  thus,  of  the  senses  which 
relate  to  distant  objects,  the  Organ  of  Hearing 
appears  to  be  wanting  in  the  Nautilus,  and 
the  Organ  of  Vision  is  comparatively  imperfect, 

*  See  vol.  iii.  pt.  1,  p.  187.  Physiological  Cata- 
logue of  the  Musoum  of  the  Royal  College  of  Sur- 
geons, 4to.  1835. 


while  those  which  take  cognizance  of  proximate 
objects  are  more  distinctly  and  extensively 
developed. 

Organ  of  Sight. — In  the  Nautilus  the  eyes 
are  supported  on  short  pedicles  which  project 
outwardly  from  the  sides  of  the  head.  They 
are  of  a  spherical  form,  slightly  flattened  ante- 
riorly ;  are  large  as  compared  with  the  pe- 
dunculated  eyes  of  Gasteropods,  but  are  of 
small  size  as  compared  with  the  complex  visual 
organs  of  the  Dibranchiates.  They  presented, 
in  Mr.  Bennett's  specimen,  the  simplest  con- 
dition of  an  organ  of  vision,  consisting  only 
Of  a  darkened  globular  cavity  or  camera  ob- 
scura,  into  which  light  was  admitted  by  a  single 
orifice,  and  a  nerve  expanded  at  the  opposite 
side  to  receive  the  impression ;  the  mechanism 
for  regulating  the  admission  of  the  impinging 
rays  was  wanting,  and  every  trace  of  that 
which  modifies  their  direction  had  disappeared. 
The  form  of  the  eye  was  maintained  by  a  tough 
unyielding  sclerotic  coat  (k,fig.  231),  which 
became  thinner  towards  the  anterior  part  of  the 
eye,  where  it  was  perforated  by  a  circular  aper- 
ture less  than  a  line  in  diameter  (w).  The  nerves 
continued  from  the  small  oval  optic  ganglion  (2) 
expand,  and  immediately  line  the  sclerotic  as  far 
as  the  middle  of  the  globe,  forming  a  strong  re- 
ticulate retina  (o),  which,  together  with  the  rest 
of  the  cavity,  is  lined  by  a  black  pigment  (n). 
There  was  no  appearance  of  vitreous  humour 
or  crystalline  lens;  but  both  parts  would  no 
doubt  be  found  to  exist  in  the  recent  state. 

In  the  Dibranchiata  the  eyes  are  sessile, 
but  in  some  species  project  beyond  the  sur- 
face of  the  head  more  than  in  others;  their 
complicated  structure  is  truly  one  of  the  most 
remarkable  features  of  the  organization  of  this 
singular  class. 

The  eyeball  in  the  Cuttle-fish  is  inclosed  in  a 
capsule  consisting  posteriorly  of  a  thick  carti- 
lage (a,  a,  fig.  234),  in  its  lateral  circumference 

Fig.  234. 


Section  of  the  Eye  of  the  Cuttle-fish. 

of  a  strong  white  fibrous  membrane  (b,  b}}  and 
anteriorly  of  the  cornea  (o). 

The  whole  of  the  inner  surface  of  the  cap- 
sule is  lined  by  a  thin  serous  membrane,  as  far 


552 


CEPHALOPODA. 


as  the  margin  of  the  thick  posterior  cartila- 
ginous orbit,  to  which  it  is"  attached,  and  is 
thence  reflected  forwards  (c,  c)  upon  the  mus- 
cles of  the  eye-ball,  also  upon  the  long  narrow 
anterior  and  inferior  ocular  cartilage  (d,  d),  and 
upon  the  exterior  fibrous  layer  of  the  sclero- 
tica;  it  is  reflected  inwards  over  the  anterior 
thickened  margin  of  the  sclerotica,  where  the 
large  anterior  aperture  of  that  membrane  re- 
mains unclosed  by  the  cornea,  and  consequently 
passes  along  its  inner  surface  like  the  mem- 
brane of  the  aqueous  humour ;  it  seems  to  us, 
however,  not  to  pass  over  the  anterior  part  of 
the  capsule  of  the  crystalline  lens,  but  into  the 
groove  (p,p)  which  divides  that  body  into  two 
parts.  The  serous  layer  above  described  can- 
not be  detached  from  the  cornea,  but  ceases  to 
be  demonstrable  as  a  distinct  membrane  where 
the  external  fibrous  coat  is  attached  to  the 
cornea.  The  space  between  the  eye-ball  and 
its  capsule,  which  is  thus  circumscribed,  is 
filled  with  a  watery  fluid,  which  is  most  abun- 
dant in  the  Calamaries.  The  cornea  is  sepa- 
rated by  the  same  fluid  from  the  eye-ball ;  but 
its  tension  and  slightly  convex  figure  is  main- 
tained by  it,  as  by  the  aqueous  humour  in  the 
eye  of  the  vertebrate  animal.  The  motions  of 
the  eye-ball  are  facilitated  by  the  secretion  of 
the  serous  sac,  as  the  movements  of  the  heart 
in  the  pericardium,  and  in  other  instances  in 
which  serous  membranes  are  developed. 

The  membrane,  of  which  we  have  just  de- 
scribed the  reflections  and  extent,  is  regarded 
by  Cuvier  as  analogous  to  the  tunica  conjunc- 
tiva, but  a  difficulty  arises  in  this  mode  of 
considering  it,  in  consequence  of  the  position 
of  the  cornea  (o),  which,  in  its  structure  and 
connection  with  the  integument,  bears  a  close 
analogy  to  the  cornea  in  Fishes.  The  charac- 
teristic difference  which  the  cornea  presents  in 
the  latter  class,  as  compared  with  that  of  the 
Cephalopoda,  is  its  adhesion  to  the  margins 
of  the  anterior  aperture  of  the  sclerotica,  by 
which  the  anterior  chamber  of  the  eye  is 
limited  to  a  very  small  space ;  while  in  the 
Sepia  it  would  seem  as  if  the  membrane  circum- 
scribing the  anterior  chamber  had  over-passed  its 
usual  bounds  in  consequence  of  the  absence  of 
any  such  adhesion  between  the  cornea  and  sclero- 
tica. When  we  consider  the  nature  of  the 
membrane  in  question,  and  the  relations  of 
the  fluid  it  secretes  to  the  cornea  and  crystal- 
line, should  we  not  be  justified  in  considering 
it,  notwithstanding  its  excessive  development, 
as  analogous  rather  to  the  membrane  of  the 
aqueous  humour,  than  to  the  conjunctiva, 
the  ratio  of  the  development  of  which  is  as 
that  of  the  eye-lids  or  folds  of  membrane  ex- 
ternal to  the  cornea,  and  of  which  we  have 
only  a  slight  rudiment  in  the  Sepia?  (v.) 

The  space  between  the  cartilaginous  orbit 
and  the  posterior  part  of  the  eye  is  circum- 
scribed by  a  membrane  (e,  e)  which  has  the 
character  rather  of  a  condensed  layer  of  cellular 
tissue  than  of  a  true  serous  membrane.  In 
this  space  is  contained  the  optic  ganglion  (jQ, 
its  filaments  (g),  and  the  surrounding  soft  white 
substance  (A),  by  some  considered  of  an  adi- 
pose, by  others  of  a  glandular  nature.  This 


cavity  is  proportionally  larger  in  Che  Octopus 
than  in  the  Sepia. 

The  eye-ball  of  the  Cuttle-fish  is  an  irregular 
spheroid,  flattened  in  the  direction  of  its  axis. 
The  vertical  diameter  is  less  than  the  horizontal, 
but  both  exceed  the  diameter  of  the  axis.  The 
eye-ball  is  remarkable  in  all  the  Dibranchiala 
for  its  considerable  development  as  compared 
with  the  size  of  the  body ;  it  is  proportionally 
largest  in  the  Calamaries,  and  smallest  in  the 
Octopods. 

The  exterior  membrane  covering  the  ante- 
rior part  of  the  eye-ball  (i)  receives  the  inser- 
tions of  the  muscles  of  the  eye,  and  seems  as 
if  it  were  formed  by  their  aponeurotic  expan- 
sions ;  it  lies  immediately  beneath  the  reflected 
layer  of  the  serous  covering,  is  of  a  soft  texture, 
and  has  a  pinkish  colour  with  a  glistening 
silver  lustre ;  in  the  Poulp  it  is  spotted  like 
the  skin.  The  entire  eye-ball  is  surrounded 
by  a  second  layer  of  membrane  (/c,  k),  having 
a  similar  texture  and  appearance;  these  are 
analogous  to  the  exterior  or  fibrous  layers  of 
the  sclerotica  in  the  eyes  of  Fishes.  We  next 
find  a  cartilaginous  layer  (/,  /)  corresponding  to 
the  internal  cartilaginous  sclerotica  of  the  Pla- 
giostomous  Fishes.  This  coat  is  very  thin, 
and  almost  membranous  posteriorly,  where  the 
fibrils  of  the  optic  ganglion  penetrate  it,  and 
where  it  presents  a  cribriform  surface  of  consi- 
derable extent,  in  which  it  may  be  observed 
that  the  orifices  of  the  sieve  are  of  consi- 
derable size,  and  not  veiy  close  together. 
Anterior  to  the  cribriform  surface  the  cartila- 
ginous sclerotica  increases  in  thickness,  but 
more  so  on  the  lower  than  the  upper  side 
of  the  eye,  and  about  the  middle  of  the  eye- 
ball it  terminates  in  a  slightly  thickened  mar- 
gin. A  layer  of  fibrous  membrane  (m,  ni) 
is  continued  from  this  margin,  along  with 
the  external  fibrous  layer  (/),  and  assists  in 
forming  the  soft  thick  anterior  part  of  the 
sclerotica,  which  forms  the  circumference  of  the 
pupillary  aperture  (w),  or  that  by  which  light  is 
admitted  to  the  cavity  of  the  eye.  The  supe- 
rior part  of  this  aperture  is  encroached  upon 
by  a  bilobed  curtain-like  process,  which  we 
have  observed  to  present  a  semi-transparent 
texture  in  the  eyes  of  some  Cuttle-fishes,  as  if  it 
were  an  abortive  formation  of  a  sclerotic  cornea: 
in  position  it  resembles  the  curtain-like  process 
depending  from  the  iris  of  the  Ray. 

The  inner  surface  of  that  part  of  the  sclero- 
tica which  lies  anterior  to  the  lens  is  lined  with 
a  dark  pigment. 

The  tunic  which  immediately  lines  the  car- 
tilaginous sclerotic  is  not,  as  in  Fishes,  a 
membrana  argentea,  or  a  vascular  choroid, 
but  consists  of  an  expansion  of  the  ner- 
vous fibres  which  are  given  off  from  the  optic 
ganglion,  connected  together  by  a  vascular 
and  cellular  tissue  (o,  o).  The  ganglion  does 
not  resolve  itself  into  these  fibres  uniformly 
from  the  circumference  to  the  centre,  but  sends 
them  off  from  its  exterior  surface  only,  so  that, 
on  making  a  section  of  the  part,  the  centre  of 
the  ganglion  presents  a  homogeneous  pulpy 
texture,  separated  by  a  distinct  external  layer 
from  the  origins  of  the  fibrils,  as  in  the  figure,/. 


CEPHALOPODA. 


553 


The  fibres,  after  perforating  the  cartilaginous 
sclerotica,  and  expanding  into  the  post-pig- 
mental retina,  extend  towards  the  groove  of  the 
crystalline,  in  a  direction  chiefly  parallel  to 
one  another,  the  tunic  formed  by  them  be- 
coming thinner  as  they  advance  forwards  ;  this 
is  joined  by  a  thin  membrane,  which  extends 
from  the  anterior  margin  of  the  cartilaginous 
sclerotica,  and  forms,  with  that  membrane,  a 
ciliary  plicated  zone  (p,  p,  where  it  is  repre- 
sented as  left  entire,)  which  penetrates  the 
groove  of  the  lens.  The  outer  surface  of  this 
thick  nervous  tunic  is  fibrous  and  flocculent, 
and  connected  to  the  sclerotica  by  a  fine  cel- 
lular tissue :  the  anterior  or  internal  surface  is 
perfectly  smooth. 

This  surface  of  the  nervous  tunic  is  co- 
vered by  a  tolerably  consistent  layer  of  a  dark 
purple-brown  pigment  (</).  Cuvier,  who  re- 
gards the  preceding  tunic  as  the  only  part 
analogous  to  the  retina  in  the  eye  of  the  Ce- 
phalopods,  expresses  his  surprise  that  this  black 
layer  is  not  an  insurmountable  obstacle  to 
vision  ;*  and  different  theories  have  been 
proposed  to  account  for  the  singular  position 
of  the  pigment  on  that  supposition.  In  the 
eyes  of  different  Sepia  which  we  had  immersed 
in  alcohol  preparatory  to  dissection,  we  have, 
however,  invariably  found  between  the  pig- 
ment and  the  hyaloid  coat  a  distinct  layer  of 
opaque  white  pulpy  matter  (r),  of  sufficient 
consistence  to  be  detached  in  large  flakes,  and 
easily  preserved  and  demonstrated  in  prepara- 
tions. We  confess,  however,  that  we  can 
discover  no  connection  between  this  layer  and 
the  thick  nervous  expansion  behind  the  pig- 
ment ;  but,  nevertheless,  we  cannot  but  regard 
it  as  being  composed  of  the  fine  pulpy  matter 
of  the  optic  nerve,  and  as  constituting  a  true 
prae-pigmental  retina. 

The  hyaloid  coat,  which  is  remarkably  dis- 
tinct in  all  the  Cephalopods,  completely  sepa- 
rates the  vitreous  humour  from  the  internal 
white  layer  above  described.  It  is  perfectly 
transparent,  and,  though  thin,  is  strong.  The 
vitreous  humour  does  not  lose  its  transparency 
when  preserved  in  alcohol. 

The  crystalline  lens  is  of  large  size,  and  is 
composed  of  two  completely  separated  portions : 
the  anterior  moiety  is  the  segment  of  a  larger 
sphere,  but  forms  the  smaller  part  of  the  lens  ; 
the  posterior  is  a  segment  of  a  smaller  sphere, 
and  forms  the  larger  part  of  the  lens.  Two 
layers  of  transparent  membrane  are  continued 
from  the  ciliary  body  between  these  segments. 
Each  of  the  segments  is  composed,  as  in  the 
lens  of  higher  animals,  of  concentric  laminae, 
which  become  denser  towards  the  centre,  where 
the  nucleus  resists  further  unravelling  of  its 
structure.  It  is  of  a  brown  colour,  and  pre- 
serves its  transparency  in  alcohol.  The  laminae 
are  composed  of  denticulated  fibres;  but  the 
minute  description  of  their  texture  and  arrange- 
ment will  be  given  in  another  place. 

The  white  substance  (h)  which  surrounds 
the  optic  ganglion  is  divided  into  lobes,  but 

.    *  "  On  ne  con9oit  pas  comment  elle  n'est  pas  un 
obstacle  insurmontable  a  la  vision." — Mem.  sur  le 
Poulpe,  p.  39. 
VOL.  I. 


exhibits  no  distinguishable  secerning  structure  ; 
the  bloodvessels  of  the  eye  ramify  between 
these  masses;  the  smaller  twigs  accompany  the 
nervous  fibrils ;  the  larger  ones  pass  forwards 
to  the  anterior  soft  margin  of  the  sclerotica. 
We  regard  this  substance  as  analogous  to  the 
so-called  choroid  gland  in  the  eyes  of  Fishes. 
Cuvier  assigns  to  it  the  function  of  defending 
the  nervous  ganglion  and  fibres  from  surround- 
ing pressure ;  and  this  is  most  probably  the 
true  final  intention  of  the  substance,  since  it 
intervenes  between  the  ganglion  and  the  mus- 
cles of  the  eye-ball. 

Of  these  we  find  three  straight  muscles  and 
one  oblique.  The  inferior  rectus  of  each  eye 
arises  from  a  small  transverse  tendon  which 
adheres  to  the  inferior  and  anterior  border  of 
the  cranial  cartilage,  to  which  it  runs  parallel, 
and  is  attached  at  its  two  extremities  to  the 
muscles  above  mentioned,  and  also  to  the  base 
or  root  of  the  anterior  elongated  cartilaginous 
orbital  plate. 

A  second  straight  muscle  arises  from  the 
posterior  margin  of  the  elongated  cartilage 
above  mentioned;  its  fibres  run  parallel  to 
those  of  the  preceding,  and  are  inserted  into 
the  external  sclerotica.  Both  these  muscles  are 
thin,  broad,  and  fleshy. 

The  oblique  muscle  arises  from  the  inferior 
and  posterior  margin  of  the  external  orbital  car- 
tilage, and  expands,  as  it  proceeds  outwards 
and  forwards,  to  terminate  in  the  external  mem- 
branous sclerotic.  These  muscles  are  readily 
exposed  by  dissecting  away  the  orbital  capsule 
from  the  under  part  of  the  eye-ball. 

A  short  and  strong  superior  rectus,  the  ten- 
don of  which  is  continuous  with  that  of  the 
opposite  side,  is  inserted  into  the  upper  part  of 
the  sclerotic. 

A  few  observations  remain  to  be  made  on  the 
structures  defending  the  anterior  part  of  the  eye- 
ball. The  cornea  of  the  Cuttle-fish  is  appa- 
rently entire;  it  is  thickest  at  its  superior  mar- 
gin (t),  where  it  is  implanted  in  a  groove  of 
the  integument ;  it  becomes  gradually  thinner 
towards  the  lower  margin,  where  it  is  over- 
lapped by  the  rudimental  eyelid  (v).  This 
consists  of  a  narrow  semilunar  fold  of  inte- 
gument, the  concavity  of  which  is  directed 
upwards  and  a  little  backwards. 

In  the  small  Cephalopod  which  Captain  Ross 
discovered  in  the  Arctic  Ocean,  and  which  has 
been  named  after  that  distinguished  and  scien- 
tific navigator,*  the  cornea  is  defended  by  a 
continuous  circular  fold  of  integument,  which 
can  be  completely  closed  by  an  orbicular 
sphincter  in  front  of  the  eye,  a  structure  which 
is  probably  required  in  this  species  in  order  to 
protect  the  cornea  against  the  spiculae  of  ice 
with  which  its  native  seas  abound,  especially 
in  the  summer  or  thawing  season.  In  the 
Calamary,  on  the  other  hand,  there  is  no  tegu- 
mentary  fold.  Upon  carefully  inspecting  the 
cornea  of  the  Cuttle-fish,  a  minute  foramen 
will  be  seen  near  the  inner  or  anterior  margin 
of  the  cornea,  covered  by  the  upper  extremity 
of  the  fold  of  integument.  The  aperture  leads  ob- 

*  See  Appendix  to  Sir  John  Ross's  Voyage,  4to. 
p.  xii.  pi.  B.  c. 

2  o 


554 


CEPHALOPODA. 


Fig.  235. 


liquely  downwards  and  backwards,  and  if  air 
be  blown  or  fluid  injected  through  it,  the  large 
cavity  surrounding  the  anterior  part  of  the  eye- 
ball will  be  distended,  and  the  cornea  ren- 
dered convex.  In  the  Poulp  the  corresponding 
aperture  (o,fig.  216)  is  somewhat  larger,  and 
situated  more  in  the  axis  of  vision  :  its  inferior 
and  posterior  margin  is  extended  beneath  the 
opposite  margin,  so  as  to  form  a  semi-transpa- 
rent curtain  behind  the  external  opening.  In 
the  common  Calamary  and  the  Onychoteuthis 
the  corneal  perforation  is  still  larger,  vertically 
oblong,  and  through  it  the  capsule  of  the  cry- 
stalline lens,  which  projects  through  the  scle- 
rotic aperture,  is  immediately  exposed  to  the 
external  medium. 

Organ  of  Hearing. — This  organ  has  hitherto 
been  found  only  in  the  Dibranchiate  division 
of  the  Cephalopods.  It  consists,  as  in  the 
Cyclostomous  or  lower  organized  cartilaginous 
Fishes,  of  an  acoustic  vestibule,  containing  a 
limpid  fluid  and  a  calcareous  body  or  otolithe 
suspended  in  a  delicate  sacculus  to  the  filaments 
of  the  auditory  nerve,  but  without  the  semi- 
circular canals,  cochlea,  or  other  parts  which 
progressively  complicate  the  Organ  of  Hearing 
in  the  higher  animals. 

The  vestibular  cavities  ( «, 
a,  fig.  235)  are  situated,  not 
at  the  sides,  but  at  the  base 
of  the  cranium  in  that  thick 
and  dense  part  of  the  carti- 
lage which  supports  the  sub- 
cesophageal  cerebral  masses. 
In  the  Cuttle-fish  the  cavities 
are  of  a  sub-quadrate  form, 
separated  only  by  a  thin  septum  (cj  ;  and  they 
are  every  where  closed,  except  at  the  entrance  of 
the  nerve.  From  their  inner  surfaces  project 
several  obtuse  moderately  elongated  processes 
(b>  b,fg.  235),  of  a  soft  elastic  texture,  which 
support  the  central  sacculus  ( d)  and  otolithe 
(e),  and  doubtless  serve  to  convey  to  it  the 
vibrations  which  affect  the  body  generally. 
The  sinuosities  in  the  intervals  of  these  pro- 
cesses seem  to  be  the  first  rudiments  of  those 
which  in  the  higher  classes  are  extended  in  the 
form  of  canals  and  spiral  chambers  within  the 
substance  of  the  dense  nidus  of  the  labyrinth. 
The  otolithe  in  the  Sepia  officinalis  is  of  an  ir- 
regular flattened  quadrangular  figure,  with  two 
of  the  angles  produced  so  as  somewhat  to  re- 
semble the  human  incus :  the  surface  next  the 
parietes  of  the  sacculus  is  convex  and  smooth, 
the  opposite  one  concave  and  broken :  it  is 
white  and  transparent.  (In  jig. 235,  the  oto- 
lithe is  seen  as  exposed  in  the  sacculus  on  the 
right  side.) 

In  the  Octopus  vulgaris  the  vestibules  are 
nearly  spherical,  and  their  parietes  are  smooth ; 
the  otolithes  are  of  an  hemispherical  figure  at- 
tached to  the  dorsal  part  of  the  membranous  sac, 
of  a  white  colour  on  the  adherent  surface,  and 
yellow  on  the  opposite  side :  the  rest  of  the 
sacculus  is  filled  with  a  transparent  gelatinous 
fluid.  The  auditory  nerve  divides  into  three 
branches,  which  spread  over  the  sacculus,  and 
convey  to  the  sensorium  the  vibrations  which 
affect  the  otolithe  and  its  sac. 


Organ  of  Hearing, 
Cuttle-fish. 


In  the  Eledone  cirrosa  the  otolithe  is  shaped 
like  the  shell  of  a  limpet,  with  the  apex  rounded 
and  curved  backwards ;  of  a  pink  colour  on  the 
sides,  but  of  a  white  semitransparent  texture 
internally. 

The  otolithes  in  all  the  Dibranchiates  effer- 
vesce with  acids,  like  other  substances  com- 
posed of  carbonate  of  lime ;  and  in  the  Poulp, 
Eledone,  and  all  the  Decapods,  except  the 
Cuttle-fish,  they  are  the  only  earthy  substances 
which  enter  into  the  organization  of  these 
animals. 

Organ  of  Smell. — The  sense  of  smell  has 
been  attributed  to  the  Cephalopods  by  all  natu- 
ralists who  have  written  on  their  habits ;  from 
Aristotle,  —  who  mentions  the  strong-scented 
herbs  which  the  Greek  fishermen  attached  in 
his  day  to  their  baits,  in  order  to  prevent  their 
being  destroyed  by  the  Mollia, — down  to 
Cuvier,  who  expressly  asserts  that  they  are  at- 
tracted by  the  odour  of  different  substances. 
But  no  organ  expressly  appropriated  to  the  ex- 
ercise of  the  olfactory  sense  has  been  deter- 
mined in  the  Dibranchiate  Cephalopods. 

In  dissecting  the  Nautilus  Pompilius,  our 
attention  was  directed  to  a  series  of  soft  mem- 
branous laminae  (h,Jig.  231)  compactly  arran- 
ged in  a  longitudinal  direction,  and  forming  a 
circular  body  very  closely  resembling  the  lami- 
nated olfactory  organ  in  Fish.  The  position  of 
these  laminae,  as  well  as  their  form  and  arrange- 
ment, supported  the  belief  that  they  exercised 
the  functions  of  an  olfactory  organ;  being 
situated  just  before  the  entrance  of  the  mouth, 
between  the  internal  labial  processes  :  nerves 
were  also  traced  to  them  from  the  inferior  labial 
ganglions.  From  analogy  we  are  inclined  to 
suppose  that  the  external  lips  in  the  Dibranchi- 
ate order  may  be  the  seat  of  the  olfactory  sense. 

Organ  of  Taste. — From  the  elaborate  struc- 
ture which  the  tongue  displays  in  both  orders 
of  Cephalopods,  there  can  be  no  doubt  but  that 
these  destructive  creatures  fully  relish  the  prey 
that  they  devour,  and,  in  correspondence  to  their 
particular  tastes,  are  led  to  select  those  species 
the  limitation  of  whose  increase  is  assigned  to 
their  charge. 

The  anterior  soft  papillose  lobes  of  the 
tongue  of  the  Nautilus  are  shewn  in  the  sub- 
joined figure  (Jig.  236),  in  which  they  are 


Fig.  236. 


denoted  by  the  letter  c;  e  indicates  the  middle 
spiny  plate,  f  the  posterior  coarser  papillose 
surface,  and  g  the  faucial  folds.  The  nerves 
of  this  part  are  derived  from  the  brain  itself,  or 
supra-cesophageal  mass. 


CEPHALOPODA. 


555 


Organ  of  Touch. — With  respect  to  the  sense 
of  touch,  the  exposed  part  of  the  integument 
of  the  Nautilus  presents  numerous  papillary 
eminences ;  and  several  of  the  naked  Cepha- 
lopods  are  remarkable  for  the  irregular  surface 
of  the  skin,  which  seems  designed  to  increase 
its  natural  sensibility.  Thus,  in  the  Crunchia 
scabra,  flattened  processes  terminating  in  nu- 
merous pointed  denticulations,  project  from 
the  surface  of  the  mantle;  in  the  Sepia papil- 
lata  the  integument  is  beset  with  branched 
papillae ;  in  Sepia  mamm'dlata  with  more  sim- 
ple obtuse  eminences ;  in  Sepia  tuberculata, 
with  tubercles;  in  Octopus  aculeatus,  with 
pointed  tubercles,  &c.  That  these  projections 
serve  to  warn  the  creature  of  the  nature  of  the 
surfaces  which  come  in  contact  with  its 
body  is  highly  probable ;  and  it  is  not  at  all 
uncommon  to  find  in  those  species,  which  have 
smooth  skins  over  the  body  generally,  that 
there  are  tubercles  in  the  immediate  neigh- 
bourhood of  the  eyes,  as  in  the  Octopus 
vulgaris,  Octopus  Lichtenaultii,  Octopus  Wes- 
terniensis,  &c. 

In  the  Nautilus,  the  more  exposed  pedun- 
culate eyes  are  expressly  provided  with  re- 
tractile sensitive  tentacles  on  each  side,  as  has 
been  already  mentioned. 

With  respect  to  the  organs  destined  for  the 
active  exercise  of  touch  or  exploration,  we 
must  suppose  that  the  numerous  tentacles  with 
which  the  Nautilus  is  so  remarkably  provided, 
from  the  softness  of  their  texture,  their  an- 
nulated  surface,  and  liberal  supply  of  nerves, 
serve  in  this  capacity  as  well  as  instruments  of 
prehension  and  locomotion.  The  less  nu- 
merous but  more  highly  developed  arms  of 

Fig.  237. 


Male  Organs,  Poulp. 


the  Dibranchiates  doubtless  exercise  the  same 
faculty,  especially  at  their  attenuated  flexile 
extremities. 

The  internal  fringed  circular  lip  surrounding 
the  mandibles,  in  both  orders  of  Cephalopods, 
presents  another  example  of  the  dermal  co- 
vering so  disposed  as  to  be  the  seat  of  delicate 
sensation. 

GENERATIVE  SYSTEM. — The  individuals  of 
the  present  class  are,  as  before  stated,  of  distinct 
sexes,  which  in  the  Dibranchiate  order  are  re- 
cognizable by  diversity  of  size,  external  form, 
colour  and  shape  of  the  internal  rudimental 
shell.  In  the  common  Calamary,  for  example, 
the  gladius  of  the  male  is  one-fourth  shorter, 
but  broader  than  that  of  the  female. 

As  only  the  female  organs  are  known  in  the 
Tetrabranchiate  order,  we  are  limited  in  the 
description  of  the  male  parts,  to  those  which 
exist  in  the  Dibranchiate  Cephalopods;  but 
from  the  close  resemblance  subsisting  in  the 
two  orders  in  the  form  of  the  organs  of  the 
female  sex,  little  difference  can  be  expected  to 
exist  in  the  structure  of  the  male  apparatus. 

In  the  Poulp  the  male  organs  consist  of  a 
testicle,  a  vas  deferens,  a  kind  of  vesicula 
seminalis,  a  gland  compared  by  Cuvier  to  the 
prostate,  the  sac  containing  the  moveable  fila- 
ments which  Needham's  description  rendered 
so  celebrated,  and  lastly  the  penis. 

The  testicle  is  situated  at  the  bottom  of  the 
visceral  sac,  and  is  composed  of  a  membra- 
nous pouch  (0,  jig.  237),  to  one  part  of  the 
inner  surface  of  which  are  attached  a  number 
of  branched  elongated  glandular  filaments  (6), 
which  swell  at  the  breeding  season,  and  dis- 
charge an  opake  white  fecundating  fluid  into 
the  sac.  From  this  cavity  the  fluid  escapes 
by  the  orifice  (c),  and  passes  into  the  vas  de- 
ferens (d).  This  is  a  narrow  tube,  indefinitely 
convoluted  upon  itself;  it  opens  into  another 
larger  canal  (e),  the  interior  of  which  is  di- 
vided by  ridges  and  incomplete  septa;  its 
texture  seems  to  be  muscular,  so  that  it  pro- 
bably serves  by  its  contractions  to  eject  the 
fluid  carried  into  it  by  the  vas  deferens.  From 
the  vesicula  seminalis  the  semen  next  traverses 
the  extremity  of  an  oblong  gland  (f),  which 
is  of  a  compact  granular  structure,  and,  like  the 
prostatic  or  Cowperian  glands,  contributes  some 
necessary  secretion  to  the  fecundating  fluid. 

Next  follows  the  muscular  pouch  (g)  con- 
taining the  filaments  or  animalcules  of  Need- 
ham  (A).  When  first  exposed,  they  present 
the  appearance  of  white  filaments,  from  six  to 
eight  lines  in  length,  packed  closely  and  regu- 
larly in  parallel  order,  in.  three  or  four  rows 
one  above  another,  from  the  fundus  to  the 
aperture  of  the  pouch  ;  and  they  are  kept  in 
that  position  by  a  spiral  fold  of  the  membrane 
of  the  pouch,  without,  however,  having  the 
slightest  adhesion  to  that  part.  For  a  long 
time  after  being  removed  from  their  position 
they  continue  to  exhibit,  when  moistened, 
motions  of  inflection  in  different  directions. 
A  short  and  narrow  canal  (i)  leads  from  the 
pouch  to  the  root  of  the  penis  (/c),  which  is 
a  short  pyramidal  body,  hollow  within,  and 
terminating  by  a  small  anterior  aperture. 
2  o  2 


556 


CEPHALOPODA. 


In  the  Sepiola  the  part  corresponding  to 
that  called  the  prostate  by  Cuvier  exists,  but 
is  relatively  smaller,  and  the  duct  by  which  it 
communicates  with  and  is  appended  to  the 
vas  deferens  is  relatively  longer ;  the  sac  of  the 
filaments  is  relatively  larger,  exceeding  doubly 
the  dimensions  of  the  testis;  the  penis  is  much 
shorter. 

In  the  Onychoteuthis  the  penis  is  merely 
grooved,  as  in  the  Pectinibranchiate  Mollusks, 
not  perforated,  and  such  may  be  expected  to 
be  its  structure  in  the  Pearly  Nautilus. 

With  respect  to  the  act  of  impregnation  in 
the  Cephalopods,  Aristotle  gives  two  accounts. 
In  the  fifth  book  of  the  Historia  Animalium 
it  is  stated  that  the  Octopus,  Sepia,  and  Cala- 
mary,  all  copulate  in  the  same  manner;  the 
male  and  female  having  their  heads  turned  to- 
wards one  another,  and  their  cephalic  arms 
being  so  co-adapted  as  to  adhere  by  the  mutual 
apposition  of  the  suckers.  In  this  act  the 
Poulps  are  described  as  seeking  the  bottom,while 
the  Cuttles  and  Calamaries  are  stated  to  swim 
freely  in  the  water,  the  individual  of  one  sex 
moving  forwards,  the  other  backwards.  Aris- 
totle also  observes  that  the  ova  are  expelled  by 
the  funnel,  which  the  Greeks  called  physetera 
(q>vo-v)TY)£ci),  and  some,  he  adds,  assert  that  the 
coitus  takes  place  through  that  part. 

From  the  position  of  the  oviduct  at  the  base 
of  the  funnel,  and  the  inclination  of  the  penis 
to  the  same  part,  from  the  left  side,  the  latter 
supposition  derives  some  probability,  espe- 
cially with  respect  to  the  Sepia  and  Sepioteu- 
this,  in  which  the  penis  is  of  large  size,  although 
true  intromission  is  physically  impossible  in 
these,  as  in  all  other  Cephalopods.  There 
may,  however,  be  an  imperfect  connexion, 
analogous  to  that  of  the  Frog,  Toad,  &c.  and 
it  is  worthy  of  remark  that  the  differences  in  the 
situation  where  the  coitus  is  said  to  take  place, 
in  Aristotle's  remarkable  account,  corresponds 
with  the  modifications  of  the  locomotive  powers 
in  the  three  genera  treated  of;  it  is  only,  for 
example,  in  the  Sepia  and  Loligo  that  the  indi- 
viduals are  provided  with  posterior  fins  for 
swimming  forwards. 

In  the  twelfth  chapter  of  the  sixth  book  of 
the  Historia  Animalium,  where  the  generation 
of  Fishes  is  treated  of,  the  Stagyrite  ob- 
serves —  f  When  they  (fishes)  bring  forth, 
the  male  following  the  female  sprinkles  the 
ova  with  his  semen : — the  same  thing  happens 
in  the  Malakia ;  for  in  the  genus  Sep ice.,  where  the 
female  deposits  the  ova,  the  male  follows  and 
impregnates  them  :  this  possibly  happens  in  like 
manner  to  other  Malakia,  but,  hitherto,  it  has 
been  observed  in  the  Sepiae  alone.'  It  reflects, 
perhaps,  little  credit  on  modern  Naturalists, 
that  the  knowledge  of  this  part  of  the  eco- 
nomy of  the  Cephalopods  should  remain  in  the 
same  unsatisfactory  and  conjectural  state  as  it 
was  two  thousand  years  ago. 

The  female  organs  exhibit  four  principal 
types  of  structure  in  the  Cephalopods. 

The  ovary  is  single  in  all. 

In  the  Nautilus  there  is  one  oviduct,  and 
one  superadded  glandular  appendage. 

In  the  Sepia  and  many  others,  there  is  also 


Fig.  238. 


Female  Organs  of  the  Nautilut. 

one  oviduct,  but  there  are  two  separated  ni- 
damental  glandular  laminated  organs  which 
open  near  its  extremity. 

In  the  Loligo  sagittata  there  are  two  distinct 
oviducts,  and  two  separate  nidamental  glands. 

In  the  Octopoda  there  are  two  distinct  ovi- 
ducts, each  of  which,  as  in  the  Ray  and  Shark, 
passes  through  a  glandular  organ  in  its  course 
towards  the  base  of  the  funnel,  but  there  are 
no  detached  glands. 

In  the  Nautilus  the  ovary  (a,  Jig.  238)  is 
situated,  as  in  the  higher  Cephalopods,  at  the 
posterior  part  of  the  visceral  sac,  in  a  distinct 
compartment  of  the  peritoneum  ;  and  the 
gizzard,  which  here  descends  lower  down  than 
in  the  Dibranchiata,  is  lodged  by  its  side. 
The  ovary  is  of  an  oblong  compressed  form, 
and  in  the  specimen 'dissected,  measured  one 
inch  and  a  half  in  length  and  one  inch  in 
breadth.  It  consists  of^  a  simple  undivided 
hollow  sac,  with  thick  and  apparently  glan- 
dular parietes,  rugose  on  the  inner  surface, 
and  having  an  anterior  aperture  (6)  with  puck- 
ered margins,  directed  forwards. 

The  ovisacs  (c,  c)  are  numerous,  of  an  oval 
form,  and  attached  by  one  extremity,  in  a 
linear  series,  along  the  internal  surface  of  the 
ovarian  sac  on  the  dorsal  aspect.  In  the 
specimen  here  described  they  were  collapsed, 
and  had  evidently  recently  discharged  their 
ova;  the  rent  orifices  by  which  these  had 
escaped  were  still  patent  and  conspicuous.  The 
tunics  of  the  ovisacs,  as  in  the  Dibranchiata, 
were  glandular,  but  the  internal  plicae  did  not 
present  the  reticulate  disposition  characteristic 
of  the  corresponding  parts  in  the  Sepia,  &c. 
The  exterior  thin  membrane  (d}  of  the  ovary 
is  continued  forwards  to  form  the  oviduct: 
the  thick  glandular  tunics  of  this  canal  com- 
mence by  a  distinct  aperture  (e),  just  above 
the  outlet  of  the  ovary,  and  continue  increasing 
in  thickness  to  the  extremity  of  the  oviduct, 
where  the  glandular  membrane  is  disposed 
in  numerous  deep  and  close-set  folds :  the 


CEPHALOPODA. 


557 


length  of  the  glandular  part  of  the  oviduct  is 
one  inch ;  its  termination  is  at  the  base  of  the 
funnel  close  to  the  anus,  and  immediately 
behind  an  accessory  glandular  apparatus. 

This  body  is  analogous  to  the  laminated 
ovarian  gland  of  the  Pectinibranchiate  Tes- 
tacea,  and,  as  in  them,  forms  no  part  of  the 
oviduct ;  but  in  the  Nautilus  it  is  extended  in 
the  transverse  direction,  and  composed  of  two 
lateral  convex  symmetrical  masses,  resem- 
bling the  corresponding  separate  symmetrical 
glands  in  the  Decapoda,  but  which  are  here 
united  by  a  third  middle  transverse  series 
of  laminae.  All  the  laminae  are  deep,  pec- 
tinated, and  close-set,  and  are  supplied  by 
a  large  artery.  The  lateral  groups  form 
conspicuous  projections  on  the  external  sur- 
face of  the  ventral  aspect  of  the  Nautilus, 
and  are  covered  internally  by  a  layer  of  thin 
tough  membrane ;  the  middle  laminae  are 
exposed. 

The  female  organs  of  the  Dibranchiate  Ce- 
phalopods  present  different  structures,  as  be- 
fore observed,  in  the  Decapodous  and  Octo- 
podous  tribes.  In  the  former  the  oviduct  or 
oviducts  have  laminated  glandular  termina- 
tions, near  to  which  are  placed  two  detached 
nidamental  glands :  in  the  latter  there  are  al- 
ways two  distinct  oviducts  which  pass  through 
laminated  glands,  but  there  are  no  detached 
superadded  glandular  organs. 

The  Sepia,  among  the  Decapodous  Cephalo- 
pods,  manifests  in  its  generative,  as  in  its 
prehensory  and  testaceous  organs,  a  near  affinity 
to  the  Tetrabranchiate  order,  while  the  form 
of  the  female  apparatus  in  the  Octopods  more 
closely  corresponds,  on  the  other  hand,  with 
the  same  parts  in  the  Oviparous  Cartilaginous 
Fishes.  The  ovarium  in  both  tribes  is  a  single 
organ,  situated  at  the  bottom  of  the  pallial  sac, 
and  consisting  of  a  capsule  and  ovisacs  di- 
versely attached  to  its  internal  surface. 

The  ovisacs  are  proportionally  larger  in  the 
Decapods  than  in  the  Octopods.  In  the 
Cuttle-fish  they  are  extremely  numerous,  and 
are  appended  by  long  and  slender  pedicles  to 
a  longitudinal  fold  of  membrane  extending 
into  the  ovarian  cavity,  from  the  dorsal  aspect 
of  the  sac.  The  plicae  of  the  internal  glan- 
dular surface  of  the  ovisacs  or  calyces  are 
disposed  in  a  reticulate  manner,  forming  cor- 
responding light- coloured  opake  lines  on  the 
external  surface,which,  being  contrasted  against 
the  dark-brown  tint  of  the  contained  ovum 
shining  through  the  transparent  areolar  space, 
occasions  the  beautiful  and  characteristic  ex- 
terior reticulate  markings  of  the  undischarged 
ovisacs. 

In  the  Genus  Rossia,  from  which  the  sub- 
joined illustration  of  the  Decapodous  type 
of  the  female  organs  is  taken  (Jig.  239),  the 
ovisacs  have  the  same  structure  and  mode 
of  attachment  as  in  Sepia,  but  they  are  rela- 
tively of  double  the  size  and  fewer  in  num- 
ber. In  the  specimen  which  we  dissected, 
we  found  the  greater  part  of  the  ovisacs  con- 
taining the  ovum  in  various  stages  of  deve- 
lopment, as  at  «,  a.  One  was  in  the  act  of 
shedding  the  ovum,  as  at  b,f;  others  were 


Fig.  239. 


Female  generative  Organs,  Rossia  palpebrosa. 
(Natural  si«e.) 

discharged,  collapsed,  and  shrivelled,  and  in 
progress  of  absorption,  as  at  c,  c.  The  pa- 
rietes  of  the  ovarium  consist  of  a  thin  and 
almost  transparent  membrane,  which  is  con- 
tinued forwards  to  form  the  oviduct  (d,  d}. 
This  canal  commences  in  the  Cuttle-fish  by  a 
round  aperture,  about  a  third  of  an  inch  in 
diameter,  immediately  beyond  which  it  dilates, 
and  continues  forwards  of  the  same  thin  and 
membranous  structure  to  within  an  inch  of  its 
extremity,  where,  as  in  the  Nautilus,  its  pa- 
rietes  are  suddenly  thickened  by  the  develop- 
ment of  a  number  of  broad,  close-set,  glan- 
dular laminae.  The  chief  difference  between 
the  Sepia  and  the  Nautilus  obtains  in  the  greater 
extent  of  the  membranous  part*  of  the  oviduct 
in  the  former. 

In  the  Rossia  the  oviduct  (rf)  differs  only  in 
greater  relative  width  :  the  terminal  gland  (e} 
is  composed  of  two  lateral  semioval  groups 
of  transverse  glandular  lamellae,  each  group 
being  divided  by  a  middle  longitudinal  groove; 
the  oviduct  was  contracted  immediately  before 
opening  into  the  interspace  of  the  glands,  and 
a  deep  but  narrow  groove,  which  is  probably 
dilated  during  the  passage  of  the  ova,  was 
continued  between  the  two  groups  of  lamellae 
to  the  termination  of  the  oviduct.  This  was 
situated  towards  the  left  side  and  behind  the 
orifices  of  the  nidamental  glands. 

The  female  organs  of  the  Sepiola  present  the 

*  In  the  original  description  of  the  Nautilus,  this 
membranous  part  of  the  oviduct  was  regarded, 
from  its  brief  extent,  and  the  sudden  commence- 
ment of  the  glandular  tunic,  as  a  connecting  process 
of  the  peritoneum  ;  it  was  accurately  represented, 
however,  in  the  figure,  (pi,  viii.  jig.  &.)  • 


158 


CEPHALOPODA, 


same  structure  as  in  Sepia  and  Rossia,  but  the 
single  oviduct  is  relatively  wider  than  in  the  latter 
genus,  the  ova  being  of  remarkably  large  size. 
In  the  Calamary  the  ovary  is  more  elongated, 
and  the  ovisacs  and  ova  are  relatively  smaller  than 
in  any  of  the  above  genera.  In  the  common 
species  ( Loligo  vulgar  is)  the  oviduct  is  single, 
but  narrower,  and  more  elongated  than  in  the 
Sepia,  and,  like  the  vas  deferens  in  the  male, 
it  is  disposed  in  convolutions;  its  terminal 
gland  is  relatively  larger  and  longer;  and  the 
detached  nidamental  glands  are  correspond- 
ingly restricted  to  a  smaller  development. 

In  the  great  Sagittated  Calamary,  which  is 
not  uncommon  on  our  north-western  shores, 
we  found  in  a  large  specimen  taken  before  the 
beginning  of  the  breeding  season,  that  the 
oviducts  commenced  by  separate  apertures 
about  two  inches  apart  from  the  anterior  sur- 
face of  the  great  ovarian  bag,  and  were  imme- 
diately disposed  in  sixteen  short  transverse 
folds,  beyond  which  they  continued  straight 
to  the  terminal  ovarian  gland.  The  whole 
length  of  each  oviduct  was  two  inches;  the 
convoluted  portion  occupying  one  inch ; 
the  straight  and  glandular  parts  each  half 
an  inch.  Monro,  in  his  anatomy  of  this 
species  of  Loligo,  conjectured  that  the  glan- 
dular appendages  of  the  biliary  ducts,  of 
•which  he  gave  a  figure,  were  the  ova:  of 
the  oviducts  and  nidamental  glands  he  had 
no  knowledge.  The  latter  parts  are  situated 
external  to  the  terminations  of  the  oviducts; 
they  are  of  a  narrow,  elongated,  flattened  form, 
about  one  inch  and  a  half  in  length,  with  a 
wide  cavity  for  moulding  the  secretion  of  the 
two  lateral  series  of  glandular  laminse. 

The  ova  which  are  contained  in  the  mem- 
branous part  of  the  oviduct  of  the  Sepia, 
consist  of  a  deep  yellow  vitellus,  inclosed, 
first,  in  a  very  delicate  vitelline  membrane, 
and,  externally,  in  a  thin,  smooth,  shining, 
easily  lacerable,  cortical  tunic,  or  chorion. 
We  have  generally  found  them  in  great  num- 
bers, squeezed  together  in  a  mass,  so  that  few 
retained  their  true  form. 

The  external  tunic  of  the  ova  in  Rossia  is 
stronger  than  in  Sepia,  and  the  form  of  the 
ovum,  which  is  elliptical,  is  consequently  bet- 
ter preserved:  the  oviduct,  in  the  specimen 
dissected  by  us,  contained  several  ova  detached 
from  one  another,  in  progress  of  exclusion, 
as  represented  in  the  figure  at  J\  f.  The  ova 
in  Sepiola,  as  in  the  two  preceding  genera, 
are  devoid  of  any  external  reticulate  markings, 
which  belong  only  to  the  ovisac  or  formative 
calyx. 

The  delicate  ova  are  defended  by  additional 
layers  of  a  horny  substance  deposited  on  their 
external  surface  by  the  terminal  gland,  which 
may  be  compared  to  the  shell-secreting  segment 
of  the  oviduct  in  the  Fowl.  When  the  ova 
quit  the  oviduct,  they  are  connected  together 
by,  and  probably  receive  a  further  covering 
from,  the  secretion  of  the  two  large  super- 
added  glandular  bodies  (g,  g,fig.  239),  the  wide 
ducts  of  which  converge  and  open  close  to  the 
termination  of  the  oviduct. 

These  bodies,  in   the  Cuttle-fish,   Sepiola, 


and  Rossia,  are  of  a  pyriform  shape  with  the 
apices,  converging  and  turned  forwards;  of  large 
size,  especially  at  the  reproductive  season,  situ- 
ated on  the  ventral  aspect  of  the  abdomen, 
but  not  attached,  as  in  the  Nautilus  and  in- 
ferior Mollusks,  to  the  mantle.  They  are  each 
composed  of  a  double  series  of  transverse, 
parallel,  close-set  semi-oval  laminae,  the 
straight  margins  of  which  are  free  and  turned 
towards  each  other  along  the  middle  line  of 
the  gland.  When  the  gland  is  laid  open,  an 
impacted  layer  of  soft  adhesive  secreted  sub- 
stance is  found  occupying  the  interspace  of 
the  two  series  of  laminae ;  in  which,  in  Rossia, 
it  is  evidently  moulded  into  a  filamentary  form, 
whence  it  escapes  by  the  anterior  orifice  above 
mentioned.  (See  h,  h,  fig.  239.) 

The  laminae  are  attached  by  their  convex 
margins  to  the  capsule  of  the  gland,  which  is 
thin,  and  probably  contractile;  it  is  com- 
pletely closed  at  every  part  save  the  anterior 
outlet,  forming  a  shut  sac  posteriorly,  and 
having  no  communication  with  the  oviduct  or 
oviducts,  for  which  these  glands  have  some- 
times been  mistaken.* 

In  the  Cuttle-fish  the  extremities  of  the 
ovarian  glands  rest  upon  a  soft  parenchymatous 
body  of  a  bright  orange  colour :  the  correspond- 
ing part  is  rose-red  in  the  Sepiola,  and  of  a 
bright  colour  in  all  the  congeneric  species.  In 
the  Sepia  this  body  is  trilobate,  consisting  of  two 
lateral  slightly  compressed  conical  portions, 
whose  obtuse  apices  are  directed  forwards,  and  a 
smaller  middle  portion  connecting  the  lateral 
ones  at  their  posterior  and  internal  angles. 
The  dorsal  surface  of  the  lateral  lobes  is  flat- 
tened, the  opposite  side  excavated  to  receive 
the  superincumbent  extremities  of  the  ovarian 
glands.  To  these  the  substance  in  question  is 
closely  attached  by  a  tough  connecting  mem- 
brane, but  has  no  correspondency  of  structure 
nor  any  excretory  outlet.  Its  texture  is  dense 
and  granular,  with  minute  cells,  the  largest  of 
which  are  in  the  centre  of  the  body,  and  are 
filled  with  a  yellowish  brown  caseous  substance. 
In  Sepiola  the  corresponding  body  is  single, 
and  is  similarly  attached  to  the  anterior  extre- 
mities of  the  two  nidamental  glands.  In  the 

9  In  the  description  of  the  anatomy  of  the  Loligop- 
sis  by  Dr.  Grant,  contained  in  the  first  volume  of  the 
Zoological  Transactions,  it  is  stated  that  "  the 
usual  large  glands  of  the  oviducts  appear  to  be 
wanting,"  p.  26 ;  whence  we  are  led  to  conclude 
that  the  oviducts  are  double  in  that  genus  as  in  the 
Octopods.  Rathke,  however,  describes  the  oviduct 
as  being  single,  and  states  that  it  is  continued 
downwards  to  terminate  at  an  aperture  situated  on 
the  ventral  surface  of  the  hinder  extremity  of  the 
body.  This  is  so  singular  a  deviation  from  the 
Cephalopodous  type  of  structure,  and  makes  so 
towards  the  Vertebrate  Organiza- 


tion, that  we  have  selected  the  figure  (Jig-  223^ 
in  which  the  learned  author  above  quoted  illustrates 
this  part  of  his  observations  on  Loligopsis,  where 
14  represents  the  ovary,  15  the  oviduct,  and  16  its 
posterior  terminal  aperture.  Further  dissection  of 
this  remarkable  genus  is,  however,  evidently  re- 
quired, in  order  to  reconcile  the  discrepancies  in 
the  accounts  of  the  anatomy  of  these  animals  which 
have  hitherto  been  published,  both  as  to  the  ge- 
nerative system  and  in  reference  to  other  important 
structures. 


CEPHALOPODA. 


SS9 


Loligines  and  in  Rossla  it  is  double;  each 
portion  (i,  i,fig.  239)  in  the  latter  genus  is  at- 
tached by  cellular  tissue  to  the  anterior  part  of  its 
corresponding  nidamental  gland,  and  is  excava- 
ted by  a  deep  groove  close  to  the  aperture  of  the 
gland  :  from  this  structure  and  their  position  it 
would  appear  that  they  assisted  in  moulding 
the  nidamentum,  and,  perhaps,  in  applying  it 
to  the  ova.  Considering  the  texture  of  these 
singular  bodies,  their  ordinarily  bright  colour, 
and  their  relative  position  to  the  generative 
apparatus,  we  believe  ourselves  justified  in 
regarding  them  as  the  analogues  of  the  glan- 
dule succenturiata  or  l  supra-renal  bodies'  of 
the  Vertebrate  animals. 

In  the  Octopodous  Dibranchiates  the  ovary  is 
a  spherical  sac  with  thick  parietes  (1,  fig.  226). 
The  ovisacs  (2)  are  racemose  or  connected  in 
bunches,  and  attached  in  the  Poulp  to  a  single 
point  of  the  ovarian  capsule,  but  in  the  Eledone 
to  about  twenty  separate  stalks  suspended  from 
the  upper  part  of  the  ovary.  The  ova,  when 
detached  from  the  ovisacs,  escape  by  a  single 
large  aperture  (3),  leading  from  the  anterior  part 
of  the  sac  into  a  very  short  single  passage, 
which  then  divides  to  form  the  two  oviducts. 
These  tubes,  in  the  unexcited  state  of  the  ge- 
nerative system,  are  membranous,  straight,  and 
of  an  uniform  narrow  diameter,  except  where 
they  perforate  a  glandular  laminated  enlarge- 
ment (4),  situated  about  one-third  from  their 
commencement;  but,  towards  the  period  of  ovi- 
position,  the  parietes  of  the  oviducts  increase 
in  thickness  and  extent,  forming  longitudinal 
folds  internally. 

The  laminated  glands  doubtless  serve  to  pro- 
vide an  exterior  covering  to  the  ova,  and  con- 
nect them  together,  thus  performing  the  func- 
tion of  the  accessory  external  glands  in  the 
preceding  tribe.  The  oviducts  ascend  behind 
the  lateral  hearts  and  venous  cavities,  and  open 
on  each  side  of  the  mediastinal  septum  of  the 
branchial  cavity  opposite  the  middle  of  the 
gills  (5,  5). 

A  glandular  body  surrounds  each  oviduct  in 
Eledone,  but  is  situated  nearer  the  lower  end 
of  the  tubes,  and  is  of  a  darker  colour  than  in 
Octopus. 

In  Argonauta  the  oviducts  are  continued  by 
a  short  common  passage  from  the  ovary,  and 
form  several  convolutions  before  they  ascend  to 
their  termination,  which  is  the  same  as  in  Oc- 
topus ;  they  differ,  however,  from  both  the 
preceding  genera  in  having  no  glandular  lami- 
nated bodies  developed  upon  them :  the  minute 
ova  of  this  genus  are,  therefore,  connected 
together  by  the  secretion  of  the  lining  mem- 
brane of  the  long  and  tortuous  oviducts. 

In  correspondence  with  the  striking  differences 
which  the  female  organs  present  in  theCephalo- 
podous  class,  it  is  found  that  almost  every  genus 
has  its  own  peculiar  form  and  arrangement  of 
ova  after  their  exclusion.  Of  these,  therefore, 
we  proceed  to  give  a  short  description  of  the 
principal  varieties. 

The  ova  of  the  Argonaut  are  invariably  found 
occupying  a  greater  or  less  proportion  of  the 
bottom  of  the  shell ;  they  are  of  an  oval  form, 
about  half  a  line  in  length  before  the  develop- 


Fig.  240. 


Ova  of  the  Argonaut. 
Fig.  241. 


Fig.  242. 


.F/g.243. 


Ova  of  the  Calatnary,    Loliyo  Vttlgaris.* 
*  From  Fcrussac,  Monographic  ties  Cephalopoda. 


560 


CEPHALOPODA. 


ment  of  the  embryo  has  commenced,  and  are 
connected  together  in  clusters  by  long  filamen- 
tary processes. 

In  the  figure  subjoined,  (Jig-  240),  A  repre- 
sents the  ova  of  the  natural  size,  B  a  group  of 
ova  at  an  early  stage  of  embryonic  develop- 
ment, magnified,  C  a  single  ovum,  still  more 
highly  magnified,  showing  the  embryo  a,  the 
rudimental  feet  &,  and  what  would  be  regarded 
as  the  vitellus  c,  in  the  ovum  of  any  of  the 
naked  Cephalopods,  but  which  the  continuator 
of  Poli  states  to  be  the  germ  of  the  shell. 
With  respect  to  the  Poulp  (Octopus)  Aristotle 
states  that  the  animals  of  this  genus  copulate 
in  winter  and  bring  forth  in  spring :  that  the 
female  oviposits  in  a  shell  or  some  secure 
cavity ;  that  the  ova  adhere  in  clusters,  like  the 
tendrils  of  the  wild  vine  or  the  fruit  of  the 
white  poplar,  to  the  internal  parietes  of  the 
cavity;  that  the  young  Poulps  are  hatched  on 
the  fifteenth  day,  and  are  then  seen  creeping 
about  in  prodigious  numbers.* 

The  ova  of  the  Calamary  (Jig.  241)  are  in- 
closed in  cylindrical  gelatinous  sheaths,  mea- 
suring from  three  to  four  inches  in  length,  and 
about  a  quarter  of  an  inch  in  diameter  at  the 
thickest  part,  narrowing  to  an  obtuse  point  at 
one  end,  and  attached  at  the  opposite  extremity 
by  a  filamentary  process,  varying  from  half  an 
inch  to  an  inch  in  length,  to  some  foreign  body, 
as  floating  wood,  &c.;  each  sheath  or  nidamen- 
tum  contains  from  thirty  to  forty  ova,  of  a 
spherical  figure,  about  a  line  and  a  half  in 
diameter  when  newly  excluded.  As  the  num- 
ber of  cylinders  attached  to  one  body  some- 
times exceed  two  hundred,  the  prolific  nature 
of  the  species  may  be  easily  conceived. 

Fig.  242  shows  the  first  appearance  of  the 
head  and  eyes  a,  at  the  stage  prior  to  the 
development  of  the  arms  and  funnel ;  b  is  the 

Fig.  244. 


Fig.  245. 


Ova  of  the  Cuttle-fish,  Sepia  Officinalis. 
*  Hist.  Animal,  lib.  v.  cap.  16. 


elongated  body,  c  the  yolk-bag.  Fig.  243 
is  another  ovum  at  a  more  advanced  stage  of 
development  :  the  pigmentum  is  now  deposited 
both  in  the  rete  mucosum  and  in  the  eye  ;  the 
arms  are  just  beginning  to  shoot  from  the  ante- 
rior circumference  of  the  head  ;  and  the  little 
funnel  may  be  observed  rising  above  the  ventral 
margin  of  the  mantle. 

The  ovaoftheSepioteuthis  are  also  spherical 
and  enveloped  in  cylindrical  sheaths,  but  these 
are  much  shorter  than  in  the  Loligo,  and  contain 
much  fewer  ova,  making  an  approach  in  this 
respect,  as  in  the  general  organization,  to  the 
Sepiae,  in  which  each  ovum  has  its  own  nida- 
mentum. 

The  eggs  of  the  Cuttle-fish  (fig.  244)  are  of 
an  oval  form,  attenuated  at  the  extremities, 
enveloped  in  a  flexible  horny  covering,  of  a 
blackish  colour,  which  is  prolonged  into  a  pe- 
dicle at  one  extremity,  and  twisted  round  some 
foreign  body.  The  length  of  ovum  from  the 
point  of  its  attachment  is  generally  an  inch, 
and  as  a  number  of  these  ova  are  always  found 
attached  close  together,  and  sometimes  to  one 
another,  they  resemble  in  this  state  a  bunch 
of  grapes,  as  the  name  '  sea-grapes,'  com- 
monly given  to  them  by  the  fishermen,  implies. 
In  the  development  of  the  Cephalopod  the 
most  interesting  circumstance,  and  one  which 
had  not  escaped  the  notice  of  Aristotle,*  is  the 
point  of  attachment  of  the  yolk-bag  (c,jig.  245), 
which  is  suspended  from  the 
head  of  the  embryo,  its  pe- 
dicle being  surrounded  by 
the  cephalic  arms,  and  passing 
down  anterior  to  the  mouth 
to  communicate  with  the 
pharynx.  The  yolk  is  a  trans- 
parent gelatinous  fluid  of  a 
spherical  form. 
In  the  embryo  of  the  Cuttle-fish  all  the 
organs,  the  exercise  of  which  is  essential  to  its 
future  welfare,  are  adequately  developed  before 
its  exclusion.  The  gills  are  very  distinct,  and 
the  respiratory  actions  are  vigorously  performed 
by  the  alternate  dilatation  and  contraction  of 
the  mantle  and  a  corresponding  elevation  and 
falling  of  the  funnel  (d),  by  which  the  little 
streams  are  expired.  The  ink-bag  has  already 
provided  a  store  of  secretion  sufficient  to 
blacken  a  considerable  extent  of  water,  and 
baffle  any  enemy  which  may  be  ready  to  remove 
the  little  Cephalopod  from  the  world  into  which 
it  is  about  to  enter.  The  pigment  of  the  rete 
mucosum  is  developed  in  several  large  spots, 
as  in  the  Calamary  (fig.  243). 

Five  concentric  layers  of  the  dorsal  shell  at 
least  are  deposited  ;  these  are,  however,  horny, 
white,  and  transparent,  except  at  the  narrow 
and  thick  end;  and  the  innermost  layers  are 
marked  with  irregular  opake  spots.  The  lateral 
fins  are  broad,  and  the  ventral  arms  are  furnished 
with  a  fin-like  expansion,  so  that  the  young 
animal  is  enabled  to  execute  movements  either 
retrograde  or  progressive  ;  and  the  eyes  are  well 


priore. 


Foetal  Sepia. 


'  Adhaeret  ovo  Sepia  nascens  parte  sui 
De  Generatione  Animalium,  lib.  iii.  c.  8. 


CEPHALOPODA. 


561 


developed  and  proportionally  large  to  direct  its 
evolutions. 

BIBLIOGRAPHY  (ANATOMICAL).  --  Aristotle, 
Historia  de  Animalibus,  cur.  Schneider,  Lipsiae, 
lib.  iv.  cap.  1,  2,  &  4  ;  lib.  v.  cap.  6  &  18  ;  lib.  vi. 
cap.  13  ;  lib.  viii.  cap.  2  &  30  ;  lib.  ix.  cap.  36. 
De  Partibus  Animalium,  lib.  iv.  cap.  9. 

In  these  several  parts  of  his  extraordinary  work 
Aristotle  indicates  nine  different  species  of  Cepha- 
lopods,  with  so  much  precision  and  so  happy  a  se- 
lection of  their  distinctive  characters,  that  modern 
naturalists  have  been  enabled  to  identify  almost 
all  the  species  which  were  studied  by  the  Stagyrite 
two  thousand  years  ago. 

Of  these  we  may  first  mention  the  Nautilus 
which  adheres  to  its  shell,  and  which  we  conceive 
may  have  been  the  Nautilus  Pompilius  ;  second,  the 
Nautilus  which  does  not  adhere  to  its  shell,  universally 
allowed  to  be  the  Argonauta  or  Paper  Nautilus  of 
the  moderns;  third,  the  Cuttle-fish  (Sepia  oflici- 
nalis);  fourth  and  fifth,  the  great  and  small  Cala- 
maries  (Loligo  vulgaris  and  Loligo  media)  ;  sixth 
and  seventh,  the  great  and  small  Poulps  ;  the 
former  is  regarded  by  Belon  and  Rondeletius  to 
have  been  the  Sepia  octopodia  of  Linnaeus  ;  but  the 
small  species,  which  Aristotle  states  to  have  been 
variegated,*  has  not  yet  been  satisfactorily  deter- 
mined ;  eighth,  the  Bolitaena,  a  genus  of  Octopods 
which  Aristotle  characterized  by  its  peculiar  odour  ; 
this  is  the  Eledona  moschata  of  Leach  ;  ninth,  the 
Eledone,  characterized  by  the  single  series  of  suck- 
ers, and  to  which  the  Eledona  cirrosa  of  Leach 
corresponds. 

Respecting  the  living  habits  of  the  Cephalopods, 
Aristotle  is  more  rich  in  details  then  any  other 
zoological  author,  and  Cuvier  has  justly  observed 
that  his  knowledge  of  this  class,  both  zoological 
and  anatomical,-  is  truly  astonishing. 

Swamtnerdam,  Biblia  Naturae,  seu  Historia  In- 
sectorum,  1737,1738,  or  «  The  Book  of  Nature/  &c. 
translated  by  Thomas  Flloyd  and  J.  Hill,  London, 
1758,  fol.  Towards  the  end  of  this  work  there 
is  a  letter  from  Swammerdam  to  Redi,  in  which 
are  given  the  first  anatomical  details,  in  addition 
to  those  of  Aristotle,  which  appeared  after  the 
revival  of  literature  :  the  external  parts  and  struc- 
ture of  the  tongue  are  carefully  described  ;  the 
viscera  and  the  nerves  with  less  exactness  ;  and 
the  organs  of  circulation  erroneously. 

Needham,  An  account  of  some  new  microsco- 
pical discoveries,  8vo.  London,  1745.  At  page  22 
we  find  the  first  dsscription  of  the  armed  suckers 
of  the  Calamaries  :  Chapter  V.  contains  the  curious 
account  of  the  seminal  filaments  of  the  male 
Cephalopods. 

Baker,  An  account  of  the  Sea-Polypus  ;  Philo- 
sophical Transactions,  vol.1.  1758.  Bohadsch,  Dis- 
seitatio  de  veris  Sepiarum  ovis,  4to.  Pragae,  1752. 
Josephus  Theophilus  Koelreuter,  Polypi  marini, 
Russis  Karakatiza  recentioribus  Graecis  oinvirovf 
dicti,  descriptio.  Nov.  Comm.  Acad.  Petropol. 
torn.  vii.  p.  321-343,  1759.  Lamorier,  Anatomic 
de  la  Seche,  et  principalement  des  organes  avec 
lesquels  elle  lance  sa  liqueur  noire  ;  Mem.  de  la 
Soc.  de  Montpellier,  torn.  i.  p.  293-300,  4to.  1766. 

John  Hunter  on  the  organ  of  hearing  in  fish  ;  Phi- 
losophical Transactions,  1782.  In  this  paper  we 
find  the  first  announcement  of  the  existence  of  an 
organ  of  hearing  in  the  class  Cephalopoda.  Nu- 
merous preparations  in  his  Collection  attest  Mr. 
Hunter's  extensive  knowledge  of  the  rich  and 
singular  organization  of  the  Cephalopods  :  for  his 
accurate  description  and  beautiful  figures  of  the 
circulating  and  respiratory  organs,  the  reader  is 
referred  to  the  second  volume  of  the  Descriptive 
and  Illustrated  Catalogue  to  the  Hunterian  Collec- 
tion, 4to.  and  to  the  first  volume  of  the  same  work, 
for  the  descriptions  of  his  preparations  of  the  hard 
parts  and  digestive  organs  of  the  Cephalopods  : 


Si 


c;,  iroini\oi, 


among  the  latter  Mr.  Hunter  had  placed  the  «  Pan- 
creas  of  the  Cuttle-fish.' 

Monro  (Secundus).  The  structure  and  physiology 
of  fishes  explained,  &c.  fol.  Edinburgh,  1785.  This 
work  contains  (p.  62)  the  anatomy  of  the  Sagittated 
Calamary  (Loligo  sagittata,  which  the  author  terms 
the  Sepia  loligo),  and  from  its  organization  he 
ably  deduces  its  true  place  in  the  natural  system, 
observing  that  '  by  most  authors  it  has  been  ranked 
among  Fishes  ;  by  Linnaeus  it  has  been  placed  among 
the  worms  :  but  perhaps  it  may  most  justly  be  con- 
sidered as  a  link  connecting  the  two  classes  of 
animals/  Monro  confirms  the  discovery  of  Hunter 
of  the  acoustic  organ,  and  figures  the  otolithe  of 
the  Calamary.  He  first  published  the  true  descrip- 
tion of  the  three  hearts,  and  rectified  the  errors  of 
Swammerdam  on  this  part  of  the  anatomy  of  the 
class  :  he  notices  the  absence  of  the  venae  ports, 
and  some  of  the  peculiarities  in  the  structure  of 
the  eye ;  but  his  description  of  the  generative 
system,  and  his  notice  respecting  some  other  particu- 
lars, as  the  urinary  and  gall-bladder,  are  erroneous. 
Scarpa,  Anatomicae  disquisitiones  de  auditu  et 
olfactu,  fol.  1789.  The  anatomical  descriptions 
relative  to  the  Cephalopods  are  limited  chiefly  to 
the  organ  of  hearing,  and  the  course  of  the  nerves  ; 
the  account  of  the  latter  is  incomplete  and  in  part 
erroneous. 

Tilesius,  in  the  Beitrage  fiir  die  Zergliederungs- 
kunst  von  H.  F.  Isenflamm,  B.  1.  Heft.  2. 

G. Cuvier,  Lecons  d'Anat.  Comparee,  1799  to  1805. 
These  five  volumes  contain  the  results  of  numerous 
researches  on  the  anatomy  of  the  Cephalopoda,  all 
characterized  by  the  author's  usual  depth  and 
accuracy.  They  are  collected  together  with  addi- 
tional details  and  beautiful  figures  in  the  celebrated 
'  Memoire  sur  les  Cephalopodes  et  leur  Anatomic/ 
published  in  1817,  in  the  Memoires  sur  les  Mol- 
lusques,  4to.  The  type  of  organization  illustrated 
by  these  researches  is  considered  in  the  author's 
subsequent  work  (the  Regne  Animal),  as  charac- 
teristic of  the  class  Cephalopoda  ;  but  the  chief  pe- 
culiarities are  found  only  in  the  Dibranchiate  Order. 
De  Blainville,  De  1'organization  des  animaux,  ou 
principes  d'anatomie  comparee,  torn.  i.  8vo.  1822. 
Contains  observations  on  the  skin  and  organs  of 
sense  of  the  Cephalopods.  Ejusdem,  Manuel  de  la 
Malacologie,  8vo.  1825. 

Home  (Sir  Everard),  Lectures  on  Comparative 
Anatomy,  4to.  1814-1828.  On  the  distinguishing 
characters  between  the  ova  of  the  Sepia  and  those 
of  the  Vermes  testacea.  Philos.  Trans,  cvii. 

Leach,  (W.E.  M.D.)  On  the  genus  Ocythoe. 
Phil.  Trans,  cvii.  Appendix  to  Tuckey's  Voyage 
to  the  Congo.  Zoological  Miscellany,  vol.  iii. 

Rathke,  Ueber  Perothis,  &c.  (on  the  anatomy  of 
the  Loligopsis);  Mem.  de  1'Acad.  Imp.  de  Peters- 
bourg,  torn.  ii.  parts  1  &  2,  p.  169,  1833. 

Roget  (P.  M.  M.D.)  Bridgewater  Treatise,  on 
Animal  and  Vegetable  Physiology,  8vo.  1834. 

Robert  Grant,  M.D.  &c.  Description  of  a  new 
species  of  Octopus  (  Oct.  ventricosus,  Grant) ;  Edinb. 
Philos.  Journal,  vol.  xvi.  p.  309.  On  the  structure 
and  characters  of  Loligopsis,  Sec.  and  on  the  anatomy 
of  the  Sepiola  vulgaris.  Leach.  Transactions  of 
the  Zoological  Society,  part  i.  4to.  1833.  Lectures, 
Lancet,  1833-4.  Outlines  of  comparative  anatomy, 
parts  1  &  2,  8vo.  1835. 

Delle  Chiaje,  Memorie  sulla  storia  degli  animali 
senza  vertebre  del  regno  di  Napoli,  1823-1829, 
4  vol.  4to. 

San  Giovanni,  Giornale  Encicl.  di  Napoli,  1824  ; 
Annales  des  Sciences  Naturelles,  torn.  xvi.  p.  305. 
( His  memoirs  on  the  structure  and  properties  of  the 
colorific  stratum  of  the  skin  of  Cephalopoda  are 
contained  in  the  above  works.) 

J.  Coldstream,  M.D.  see  Edinb.  New  Philosophi- 
cal Journal,  July,  1830,  p.  240  ;  and,  On  the  deve- 
lopment of  the  ova  of  Sepia  officinalis,  Proceedings 
of  the  Zoological  Society,  part  i.  1833,  p.  86. 

Mayer,  Analekten  fur  Vereleichenden  Anatomic, 
4to.  1835. 


562 


CERUMEN— CETACEA. 


Ferussac,  M.  le  Baron,  fy  A.  D'Orbigny,  Mono- 
graphic des  Cephalopodes  Acetabuliferes,  folio, 
Paris,  1835.  This  splendid  work  is  published  in 
numbers,  of  which  eleven  have  appeared.  As  yet 
the  letter-press  extends  only  to  the  general  intro- 
duction. 

Broderip,  (W.  J.)  Observations  on  the  animals 
hitherto  found  in  the  shells  of  the  genus  Argonauta, 
Zoological  Journal,  vol.  iv.  p.  57. 

Richard  Owen,  Memoir  on  the  Pearly  Nautilus 
(Nautilus  Pompilius,  Linn.)  4to.  8  plates,  1832. 
This  work  contains,  besides  the  description  of  the 
structure  which  characterizes  the  lower  or  Tetra- 
branchiate  order  of  the  class,  some  additional  par- 
ticulars on  the  structure  of  the  infundibulum,  and 
of  the  brain,  and  on  the  function  of  the  superadded 
branchial  hearts,  in  the  Dibranchiate  order  of 
Cephalopods.  Descriptive  and  illustrated  Catalogue 
of  the  Physiological  Series  in  the  Museum  of  the 
Royal  College  of  Surgeons,  4to.  vol.  iii.  contains 
an  account  of  the  organs  of  sight  and  hearing  in 
the  Cephalopods,  1835.  Description  of  a  new  genus 
of  Cephalopoda  (Rossia).  Appendix  to  Sir  John 
Ross's  Voyage,  1835.  Descriptions  of  some  new 
species ;  and  anatomical  characters  of  the  Orders, 
Families,  and  Genera  of  the  class  Cephalopoda, 
Proceedings  of  the  Zoological  Society,  March,  1836. 
(Richard  Owen.) 

CERUMEN,  (Germ.  Ohrenschmalz.)— This 
secretion,  formed  by  the  glands  of  the  ex- 
ternal ear,  has  been  examined  by  Fourcroy 
and  Vauquelin,  and  more  in  detail  by  Ber- 
zelius.*  According  to  Vauquelin  it  consists 
of  0'625  of  a  brown  butyraceous  oil,  soluble 
in  alcohol,  and  0-375  of  an  albuminous  sub- 
stance, containing  a  peculiar  bitter  extrac- 
tive matter.  Berzelius  observes,  that,  when 
first  secreted,  cerumen  appears  as  a  yellow 
milky  fluid,  which  gradually  acquires  a  brown- 
ish colour  and  viscid  consistency.  Digested 
in  ether  it  imparts  to  it  fatty  matter,  which  re- 
mains when  the  ethereal  solution  is  distilled  off 
water ;  it  has  a  soft  consistence,  is  nearly  co- 
lourless, and  contains  stearin  and  elain  sepa- 
rable by  alcohol ;  it  is  easily  saponified,  and 
the  soap  which  it  forms  has  a  rank  unpleasant 
smell  and  taste;  and  when  decomposed  by  mu- 
riatic acid,  the  fatty  acids  separate  in  the  form 
of  a  white  powder,  which  rises  with  difficulty 
to  the  surface,  and  fuses  at  about  105*.  The 
portion  which  remains  after  the  action  of  ether 
imparts  a  yellow  colour  to  alcohol,  and  on  its 
evaporation  there  remains  a  yellow-brown  ex- 
tractive matter,  soluble  in  water,  and  leaving 
after  the  evaporation  of  its  aqueous  solution  a 
yellow,  transparent,  and  shining  varnish,  which 
is  viscid  and  inodorous,  but  intensely  bitter ; 
when  burned,  it  exhales  a  strong  animal  odour, 
and  leaves  an  ash  of  carbonate  of  potash  and 
carbonate  of  lime,  without  any  trace  of  a  chlo- 
ride. It  is  completely  precipitated  from  its 
aqueous  solution  by  neutral  acetate  of  lead. 
That  part  of  cerumen  which  is  not  soluble  in 
alcohol  yields  to  water  a  small  proportion  of 
pale  yellow  matter,  which,  when  obtained  by 
evaporation,  has  a  piquante  taste ;  it  is  not 
precipitable  by  salts  of  lead,  corrosive  subli- 
mate, or  infusion  of  galls,  and  contains  no 
traces  of  phosphoric  or  chlorine  salts.  The 
residue  of  the  cerumen,  insoluble  in  water  and 

*  Lehrbuch  der  Thierchemie. 


alcohol,  gelatinises  in  acetic  acid,  but  is  only 
partially  dissolved  by  it;  that  which  is  taken 
up  appears  to  be  albumen;  and  the  undis- 
solved  portion  is  brown,  viscid,  and  transpa- 
rent; digested  in  dilute  caustic  alkali  it  imparts 
a  yellow  colour,  but  a  small  portion  only  is 
dissolved ;  and  as  nothing  is  thrown  down  by 
supersaturation  with  acetic  acid  and  ferrocy- 
anate  of  potash,  it  is  not  albumen  that  is  taken 
up  :  the  acid  solution,  however,  is  copiously 
precipitated  by  infusion  of  galls,  so  that  it 
contains  some  peculiar  principle.  The  residue 
which  resists  the  action  of  dilute  alcali,  when 
boiled  in  concentrated  solution  of  caustic  pot- 
ash, becomes  brown,  and  smells  like  horns  imi- 
larly  treated;  a  part  of  it  seems  to  form  a 
compound  with  the  alkali  insoluble  in  the  ley, 
but  soluble  in  water,  in  which  respect  it  re- 
sembles horn,  but  it  differs  from  it  in  not 
being  precipitated  from  its  solution  by  muriatic 
acid,  nor  ferrocyanate  of  potash,  and  scarcely 
by  infusion  of  galls.  It  appears,  therefore, 
that  cerumen  is  an  emulsive  combination  of  a 
soft  fat  and  albumen,  together  with  a  peculiar 
substance,  a  yellow  and  very  bitter  matter 
soluble  in  alcohol,  and  an  extractive  substance 
soluble  in  water:  its  saline  contents  appear  to 
be  lactate  of  lime  and  alkali,  but  it  contains 
no  chlorides  and  no  soluble  phosphates.  When 
cerumen  accumulates  and  hardens  in  the  ear  so 
as  to  occasion  deafness,  it  is  easily  softened  by 
filling  the  meatus  with  a  mixture  of  olive  oil 
and  oil  of  turpentine,  by  which  its  fatty  matter 
is  dissolved. 

(W.  T.Brande.) 


CERVICAL    NERVES. 

NERVES. 


See    SPINAL 


CETACEA;  Gr.  x»rr»7,  hhtpwi,  Aristotle; 
Eng.  Whale  tribe,  Cetaceans;  Fr.  Cetacts ; 
Germ.  Wall-fische. 

[An  order  of  mammiferous  animals,  distin- 
guished, as  regards  outward  characters,  by  the 
absence  of  hinder  extremities,  neck,  hair,  and 
external  ears;  and  by  the  presence  of  a  large 
horizontal  caudal  fin,  and  the  fin-like  form  of 
the  anterior  extremities,  the  bones  of  which  are 
shortened,  flattened,  and  enveloped  in  a  thick 
unyielding  smooth  integument.  With  this  con- 
figuration the  Cetaceans  are  fitted  only  for 
aquatic  life,  and  reside  habitually  in  the  waters 
of  the  sea  or  of  large  rivers :  their  resemblance 
to  the  true  Fishes  is  so  close  that  many  natu- 
ralists, since  the  revival  of  literature,  and  the 
vulgar  in  all  ages,  have  regarded  them  as  mem- 
bers of  the  same  class.  Aristotle,  from  his 
anatomical  knowledge,  was  aware  of  the  essen- 
tial differences  between  the  Whales  and  Fishes, 
but  it  is  not  absolutely  necessary  to  seek  for 
internal  characters  to  establish  the  real  distinc- 
tion which  subsists  between  these  different  de- 
nizens of  the  deep ;  the  horizontal  position  of 
the  tail-fin  at  once  distinguishes  the  cetacean 
from  the  fish,  in  which  that  fin  is  vertical.  This 
difference  relates  to  the  different  nature  of 
the  respiration  of  the  Whale,  which  is  by 
lungs,  and  consequently  necessitates  a  frequent 
rising  to  the  surface  of  the  water  to  breathe  the 


CETACEA. 


563 


air,  and  a  corresponding  modification  of  the 
chief  organ  of  locomotion. 

With  the  lungs  are  also  associated  the  pre- 
sence of  warm  blood,  a  double  circulation,  an 
epiglottis,  and  a  diaphragm,  a  true  viviparous 
generation,  a  nourishment  of  the  young  by  a 
mammary  secretion,  and  in  short  all  the  essen- 
tial parts  of  a  mammiferous  organization. 
The  order  is  subdivided  as  follows : 
Tribe  I.  PHYTOPHAGA. 

Char.  Teeth  of  different  kinds ;  molars 
with  flattened  crowns,  corresponding  to 
the  vegetable  nature  of  their  food. 
Mamma,  two,  pectoral.  Lips  provided 
with  stiff  bristles.  External  nostrils, 
always  two,  situated  at  the  extremity  or 
upper  part  of  the  rostrum,  which  is  ob- 
tuse. 

Genus  MANATUS,  Cuv. 
Char.  Incisors  §  (two  superior,  deciduous 
in  the  foetus,  not  replaced).  Molars  f  f, 
grinding  surface  with  tri-tuberculate 
transverse  ridges.  Body  with  a  few 
scattered  bristles.  Anterior  extremities 
each  provided  with  four  nails.  Tail-Jin 
oval. 

Species   1.    Manatus  Americanus,    Cuv. 
Trichechus  Manatus,  Linn. :   the  Ma- 
natee.    Lamantin  d'Amerique,  Cuv. 
2.    Manatus    Africanus,    Lamantin    du 

Senegal,  Cuv. 
Genus  HALICORE,  Cuv. 
Char.  Incisors  §.  (In  the  young  animal 
the  two  superior  permanent  incisors  are 
preceded  by  two  deciduous  ones ;  six 
or  eight  deciduous  incisors  in  the  lower 
jaw  which  have  no  permanent  succes- 
sors). Molars  \\\  (in  the  young  ani- 
mal f§);  the  grinding  surface  exhibits  a 
rim  of  enamel  at  the  circumference  and 
a  slightly  excavated  centre  of  ivory. 
Body,  with  a  few  scattered  bristles. 
Upper  lip  with  bristly  mustaches.  An- 
terior extremities  without  nails.  Tail- 
fin  very  broad,  crescentic. 
Species  1.  Halicore  Indicus,  Cuv.  The 
Indian  Dugong,  or,  more  properly, 
Duyong. 

2.  Halicore  Tabernaculi,  Ruppel.  Du- 
gong of  the  Red  Sea. 
Genus  RYTINA,  Illiger.  Incisors  none. 
Molars  \  \,  large,  lamelliform,  of  a 
fibrous  structure,  with  the  triturating 
surface  roughened  by  tortuous  furrows. 
Body,  without  hairs,  but  covered  by  a 
rough  and  thick  fibrous  epidermis.  An- 
terior extremities  terminated  by  an  un- 
guiform  callosity.  Caudal-Jin  crescent- 
shaped,  each  angle  terminated  by  a 
horny  plate. 

Species.  Rytina  Stelleri,  Le  Stellere,  Cuv. 
This  species  inhabits  the  seas  of  Kamt- 
schatka.  It  was  discovered  by  the 
Russian  naturalist,  Steller,  after  whom 
it  is  named ;  and  is  described  by  him 
with  much  zoological  and  anatomical 
detail  in  the  Nova  Comment.  Petrop. 
t.  ii.  p.  294,  (1751,)  under  the  name  of 
the.  Manati  or  Vacca  marina. 


Tribe  II.  ZOQPHAGA. 

Char.  Teeth  of  one  kind  or  wanting,  not 
adapted  for  mastication.  Mamma,  two, 
pudendal.  External  nostrils,  double 
or  single,  situated  on  the  top  of  the 
head. 

A.  with  the  head  of  moderate  size. 
Family  DELPHINID^E.     Teeth  in  both 
jaws,  all  of  simple  structure,  and  gene- 
rally conical  form.     No  co2cum. 

Genus  DELPHINORHYNCHUS.  Rostrum 
very  long  and  narrow,  continued  not 
abruptly  from  the  forehead.  Teeth  very 
small  and  numerous. 

Ex.  Delphinorhynchus  micropterus.  (Fred. 
Cuvier,  Cetace"s,  pi.  viii.  fig.  1.) 

Genus  DELPHINUS.  Rostrum  narrow, 
of  moderate  length,  continued  abruptly 
from  the  forehead.  Teeth  conical, 
slightly  recurved,  numerous. 

Ex.  Delphinus  Delphis,  the  common  Dol- 
phin; Delphinus  Tursio,  the  Spouter 
or  small  Bottle-nose  Whale  of  Hunter. 

For  the  other  numerous  species  of  this 
genus  consult  F.  Cuvier,  Histoire  des 
Cetaces,  p.  147  et  seq. 

Genus  INI  A.  Rostrum,  as  in  the  genus 
Delphinus.  Teeth  mammilliform. 

Species.  Inia  Boliviensis;  (Fred.  Cuvier, 
Cetaces,  pi.  x,  bis,  and  xi,  cranium); 
inhabits  the  great  rivers  of  South  Ame- 
rica. 

Genus,  PHOC^ENA.  Rostrum  short,  broad. 
Teeth  conical  or  compressed. 

Ex.    Phoccena    communis,    the    common 
Porpoise ;  Phocana  orca,  the  Grampus ; 
Phocesna  globiceps,   L'Epaulard,  Cuv. 
Phoctena  leucas,  the  Beluga,*  &c. 
The  following  genera  seem  to  form  the  types 
of  as  many  distinct  families  of  Zoophagous 
Cetaceans. 

Genus  MONODON.  Rostrum  short  and 
broad.  No  other  teeth  save  two  in  the 
upper  jaw,  in  the  form  of  tusks,  situated 
horizontally,  and  both  of  which  continue 
in  the  rudimental  condition  in  the  female, 
while  in  the  male  one  projects  far  be- 
yond the  jaws  in  the  line  of  the  axis  of 
the  body. 

Ex.  Monodon  monoceros,  Linn.  The 
Narwhal. 

Genus  HYPEROODON.  Rostrum  of  mo- 
derate length,  extending  abruptly  from 
a  very  elevated  cranium.  Two  small 
teeth  in  the  lower  jaw ;  small  callous 
tubercles  on  the  palate. 

Ex.   Hyperoodon  Dalei ;  the  great  Bottle- 
nose  Whale  of  Hunter. 
Genus  PLATANISTA.     Rostrum  very  long 
and  compressed,  enlarged  at  the  extre- 
mity.    Teeth  numerous;  in  both  jaws 
conical  and  recurved.     Cranium  enlar- 
ged by  osseous  processes.     A  coecum. 
Ex.  Plntanista  Gangetica.  The  Gangetic 
Dolphin. 

*  This  species  has  no  dorsal  fin,  and  on  that  ac- 
count has  by  some  naturalists  been  regarded  as 
forming  the  type  of  a  distinct  genus,  under  the 
name  of  Delphinapterus, 


564 


CETACEA. 


B.  With  the  head  of  immoderate  size, 
equalling  one-third  the  length  of'  the 
body. 

Family  I.  CATODONTID^.     Teeth  nu- 
merous, conical,  but  developed  only  in 
the   lower  jaw.     External  nostrils  or 
blow-holes  confluent ;  no  coecum. 
Genus  CATODON.     No  dorsal  fin. 
Ex.    Catodon   macrocephalus ;     Physeter 
macrocephalus,  Shaw.     The  great  Sper- 
maceti Whale. 

Genus  PHYSETER.    A  dorsal  fin. 
Ex.  Physeter  Tursio,  Linn.     The  High- 

finned  Cachalot,  Shaw. 
Family  BAL^NID^.      No    teeth;   their 
place  supplied  by  the  plates  of  baleen 
or  whalebone  attached  to  the  upper  jaw. 
Blow-holes  distinct;  a  coecum. 
Genus   BAL^ENOPTERA.     A    dorsal    fin ; 
pectoral  integument  plicated;   baleen- 
plates  short.     (See  Jig.  259.) 
Species.  Balanoptera  Boops,  Cuv.;    the 

Jubarte  or  great  Rorqual. 
Balanoptera  rostrata,  Lacep. ;  the  Piked 
Whale  of   Sibbald    and  Hunter,   sus- 
pected by  Cuvier  to  be  the  young  state 
of  the  Baltenoptera  Boops. 
Balanoplera  Musculus,   Cuv.;    the  Me- 
diterranean Rorqual. 

Baltenoptera  Antarctica,  Cuv.;  the  South- 
ern or  Cape  Rorqual. 
Genus  BALJENA.     No  dorsal  fin;  pectoral 
integument  smooth;  baleen-plates  long. 
Species.  Bal&na  mysticetus,  Linn.    The 
great  Whalebone  Whale    of  Hunter; 
great  Mysticete. 

Baltena  Australis,Cuv.  The  Cape  Whale.] 
ORGANS  OF  MOTION.  —  Swimming  is  the 
principal  mode  of  progression  of  the  Cetaceans, 
but  the  Phytophagous  species  appear  to  have 
the  power,  in  order  to  feed  upon  marine  plants, 
of  crawling  and  walking  at  the  bottom  of  the 
sea  by  means  of  their  anterior  members,  which 
in  other  Cetaceans  are  exclusively  natatory 
organs. 

The  head,  in  all,  has  so  little  mobility,  that 
its  axis  can  be  but  slightly  altered,  without 
that  of  the  body  altering  also. 

In  the  form  and  composition  of  the  skull 
the  Cetaceans  of  both  tribes  present  many  im- 
portant differences,  as  compared  wtth  other 
mammiferous  animals.  In  the  Herbivorous 
genera  the  bones  are  dense  and  massive,  and 
where  they  are  not  anchylosed  their  connection 
is  of  a  loose  kind.  In  the  Dugong  the  skull  is 
more  especially  remarkable  for  the  large  size  of 
the  intermaxillary  bones  (a,  a,  figs.  246,  247), 
which  extend  backwards  as  far  as  the  middle 
of  the  temporal  fossae,  and  are  bent  down  ante- 
riorly over  the  symphysis  of  the  lower  jaw,  so 
as  to  terminate  nearly  on  a  level  with  its  infe- 
rior margin.  This  extent  and  shape  is  required 
in  the  Dugong  for  the  lodgement  of  the  perma- 
nent incisors  (b,  b),  which  are  developed  to  a 
large  size,  one  in  each  intermaxillary  bone, 
and  consequently  the  nostrils  are  placed  much 
higher  and  further  from  the  mouth  than  in  the 
Manatee,  in  which,  in  consequence  of  the  small 
deciduous  incisors  having  no  successors,  the 


Fig.  246. 


Skeleton  of  the  Dugong. 

intermaxillary  bones  are  of  much  smaller  size. 
The  form  of  the  bony  aperture  of  the  nostrils 
(c,fg.  247)  in  both  the  Dugong  and  Manatee  is 
a  large  oval,  which  in  the  Dugong,  as  in  the 
typical  Cetaceans,  is  directed  upwards.  The 
entire  cranium,  and  especially  the  frontal  bones 


CETACEA. 


565 


Fig.  247. 


Skull  of  the  Dugong. 

(d,  d),  are  consequently  proportionally  shorter 
than  in  the  Manatee.  The  processes  of  the 
frontal  bone,  which  form  the  superior  boundary 
of  the  orbits,  are  thinner  and  more  rugose  in 
the  Dugong;  the  portion  of  the  superior  max- 
illary bone,  which  serves  as  the  floor  of  the 
orbit,  is  narrower ;  the  malar  bone  (e,  e,  Jigs. 
246,  247),  which  forms  by  its  curvature  the 
anterior  and  inferior  margins  of  the  orbit,  is 
more  compressed  and  descends  lower  down. 
The  lachrymal  bone,  which  is  situated  at  the 
anterior  angle  of  the  orbit  (f,Jig.  246),  is  of 
larger  relative  size  than  in  trie  Manatee ;  but, 
as  in  that  species,  it  is  imperforate.  The  zygo- 
matic  process  of  the  temporal  bone  (g,figs. 
246,  247),  which,  in  the  Manatee,  is  propor- 
tionally thicker  than  in  any  other  animal,  is  of 
more  ordinary  dimensions  in  the  Dugong,  being 
more  compressed,  and  extended  further  back- 
wards. The  connexions  of  the  bones  of  the 
cranium  are  the  same  in  both  these  herbivorous 
species.  The  parietal  bones  (h,  Jig.  247)  are 
developed  in  the  foetus,  as  usual,  each  from  a 
distinct  centre  of  ossification ;  but,  what  is 
very  remarkable,  the  ossification  of  the  inter- 
parietal  bone  also  proceeds  from  two  lateral 
and  symmetrical  points :  these  four,  originally 
distinct  bones,  are,  however,  very  early  anchy- 
losed  together,  and  also  to  the  superior  occipi- 
tal bone,  which  latter  junction  takes  place  be- 
fore the  three  other  elements  of  the  occipital 
bone  have  coalesced.  The  parietal  cristae  are 
widely  separated  from  each  other.  The  occiput 
is  narrower,  and  its  crest  is  less  marked  than 
in  the  Manatee.  In  the  interior  of  the  cranium 
we  may  observe  that  there  is  no  bony  tento- 
rium,  and  that  the  cribriform  plate  of  the 
ethmoid  is  reduced  to  two  simple  depressions, 
widely  separated  from  one  another,  and  termi- 
nating anteriorly  in  two  or  three  small  foramina. 
There  is  no  sella  turcica  for  the  pituitary  gland. 


The  optic  foramen  presents  the  form  of  a  long 
and  narrow  canal. 

The  lower  jaw  (i,fig.  246)  corresponds  in 
depth  to  the  curvature  and  length  of  the  inter- 
maxillary bones,  and  is  bent  downwards  at  the 
symphysis  in  a  corresponding  direction,  pre- 
senting on  the  anterior  surface  of  this  part  three 
or  four  rough  and  shallow  alveoli,  in  two  of 
which  Sir  Everard  Home*  discovered  a  small 
rudimental  incisor. 

The  skull  of  the  true  or  Zoophagous  Ceta- 
ceans is  characterized  by  the  great  breadth  and 
elevation  of  the  cranium,  by  the  almost  verti- 
cal direction  of  the  nasal  passages,  by  the  de- 
pressed position  of  the  orbits  as  compared  with 
the  bony  nostrils, — a  character  which  is  still 
more  marked  in  these  than  in  the  herbivorous 
species;  and,  lastly,  by  the  extreme  prolonga- 
tion of  the  oral  or  labial  portions  of  the  inter- 
maxillary and  maxillary  bones.  The  superior 
maxillaries  (g,  g,  Jig.  268)  are  also  developed 
posteriorly  so  as  to  rise  anterior  to  the  frontal 
bones,  over  which  they  are  expanded,  extending 
as  far  as  the  level  of  the  nasal  bones,  which 
form  almost  the  summit  of  the  cranium.  Such 
at  least  is  the  general  configuration  of  the  skull 
in  the  Delphinid*,  which  constitute  the  largest 
family  of  the  Zoophagous  tribe. 

In  the  Phoceena  globiceps,  of  which  the  skull 
is  represented  in  Jig.  248,  the  cranium  is  very 
Fig.  248. 


Skull  of  the  Roundfieaded  Porpesse  ; 
Phocaena  globiceps. 

convex  behind ;  the  occipital  crest  (a,  a)  sur- 
rounds the  upper  part  and  descends  on  each 
side  to  the  middle  of  the  temporal  cristse  :  the 
posterior  convexity  is  not  formed  by  the  occi- 
pital bone  alone,  but  also  by  the  interparietal 
and  parietal  bones  (b,  b),  the  whole  being  an- 
chylosed  together  at  a  very  early  period.  The 
parietal  bones  descend,  as  in  the  human  sub- 
ject, between  the  temporal  and  the  frontal  ( c,  c), 
and  reach  the  lateral  ala  of  the  posterior  sphe- 
noid. As  the  parietals  terminate  behind  the 
*  See  PI.  xiv.  Philos.  Trans.  1820. 


566 


CETACEA. 


transverse  superior  cranial  or  occipital  ridge, 
and  the  superior  maxillary  bones  approach  very 
close  to  the  same  part,  the  frontal  bone  seems 
to  be  represented  by  a  very  narrow  osseous 
band  traversing  the  cranium  from  right  to  left, 
and  dilating  at  each  extremity  to  form  the  roof 
of  the  orbit  (c,  c).  But  when  the  maxillary 
bones  which  have  extended  over  the  whole 
anterior  part  of  the  cranium  are  raised,  the 
frontal  bone  is  then  seen  to  be  of  much  larger 
size  than  the  external  appearances  indicate. 

The  two  nasal  bones  (d,  d)  are  in  the  form 
of  oblong  rounded  tubercles,  set  deeply  in 
two  depressions  in  the  middle  of  the  frontal 
bone,  and  in  front  of  which  the  nasal  passages 
(e,  e)  are  continued  vertically  downwards. 
The  two  intermaxillaries  (f,f)  form  the  exter- 
nal and  anterior  margin  of  the  nasal  apertures. 
The  cribriform  plate  of  the  ethmoid  consti- 
tutes the  posterior  wall  of  the  nasal  passages ; 
and  in  this  plate  there  are  three  or  four  small 
perforations.  The  remainder  of  the  circum- 
ference of  the  bony  nostrils  is  formed  by  the 
maxillary  bones,  of  which  a  small  part  appears 
at  g :  their  septum  is  the  vomer,  which  is 
joined  to  the  ethmoid  as  usual. 

The  malar  bone  is  an  irregular  flattened  bone, 
which  assists  the  frontal  in  forming  the  orbit, 
and,  like  it,  is  covered  by  the  maxillary  bone  : 
it  sends  backwards  a  long  and  slender  process, 
which  articulates  with  the  zygomatic  process 
of  the  temporal  bone,  and  forms  the  only 
bony  boundary  of  the  lower  part  of  the  orbit. 
The  zygomatic  process  of  the  temporal  bone  is 
united  to  the  post-orbital  process  of  the  frontal, 
bounding  the  orbit  posteriorly;  and  thus  the 
zygomatic  arch  is  exclusively  formed  by  the 
temporal  bone  :  this  bone  terminates  at  the 
temporal  ridge,  having  but  a  small  extent  of 
development  on  the  side  of  the  cranium,  and 
not  entering  at  all  into  the  composition  of  the 
posterior  convex  surface.  At  the  base  of  the 
cranium  the  basilar  and  the  lateral  occipitals 
develop  expanded  plates,  which  join  the  ptery- 
goideal  alae  of  the  sphenoid,  and  a  lamina  of 
the  temporal  bone,  to  which  the  petrous  and 
tympanic  bones  have  a  ligamentous  attach- 
ment. The  parietal  bones  also  extend  behind 
the  temporals,  to  aid  in  completing  the  basilar 
walls  of  the  cranial  cavity,  so  that  the  temporal 
bone  is  almost  excluded  from  entering  into  the 
composition  of  the  cranium,  serving  merely  to 
close  some  small  vacancies  left  by  the  parietals : 
this  structure  is  of  great  interest,  as  we  perceive 
in  it  the  commencement  of  that  displacement 
of  the  temporal  bones  from  the  cranial  parietes 
which  is  characteristic  of  the  small-brained  and 
cold-blooded  classes  of  Vertebrata. 

The  differences  between  the  Dugong  and 
Manatee  in  respect  to  the  structure  of  the 
cranium,  we  have  seen  to  resolve  themselves 
almost  entirely  into  the  expansion  and  elonga- 
tion of  the  intermaxillary  bones  in  relation  to 
the  tusks,  which  they  are  destined  to  support  in 
the  former  animal ;  and  we  shall  find  on  a  com- 
parison of  the  skulls  of  the  Delphinida  toge- 
ther, that  they  also  differ  from  one  another, 
chiefly  in  the  forms  and  proportions  of  their 
maxillary  and  intermaxillary  bones. 


The  Delphinorhynchi  are  characterized,  first, 
by  an  extremely  narrow  rostrum,  the  length  of 
which  is  four  times  greater  than  that  of  the 
cranium ;  secondly,  by  the  anterior  curvature 
of  the  posterior  extremities  of  the  intermaxil- 
laries, which,  as  it  were,  draw  forwards  in  the 
same  direction  the  maxillary,  the  frontal,  and 
even  the  occipital  bones ;  thirdly,  by  the  posi- 
tion of  the  nasal  bones,  which  are  sunk  in 
between  the  frontals  and  intermaxillaries ; 
fourthly,  by  the  very  diminutive  size  of  the 
temporal  fossae. 

The  Delphini,  properly  so  called,  have  also 
a  narrow  rostrum,  but  its  length  is  scarcely 
three  times  that  of  the  cranium ;  the  posterior 
extremities  of  the  intermaxillary  bones,  toge- 
ther with  the  maxillary  and  frontal  bones,  are 
raised,  but  not  bent  forwards;  the  tempoial 
fossae  in  some  species  are  as  diminutive  as  in 
the  Delphinorhynchi,  but  in  others  gradually 
recede  from  that  character,  and  approach,  by 
•their  expansion,  to  the  form  which  they  exhibit 
in  the  next  generic  type,  viz.  the  Inia. 

The  cranium  in  this  genus,  besides  the  great 
extent  of  the  temporal  fossa,  and  the  strong 
crista  which  forms  its  superior  border,  is  also 
characterized  by  the  shortness  of  the  orbital 
fossa. 

In  the  Phocana  the  rostrum  is  as  remarkable 
for  its  breadth  as  it  is  in  the  Delphini  for  its 
narrowness ;  this  results  from  the  great  lateral 
development  of  the  intermaxillary  and  max- 
illary bones ;  but  the  antero-posterior  extension 
of  the  bones  is  diminished,  and  the  length  of 
the  rostrum  does  not  exceed  that  of  the  cranium. 

The  Narwhals  (Monodon)  manifest  their 
affinity  to  the  Porpesses  (Phocana)  by  the 
breadth  and  shortness  of  the  rostrum,  but  differ 
from  that  and  every  other  genus  of  Cetacea  in 
the  development  of  horizontal  tusks  in  the  inter- 
maxillary bones,  of  which  the  left  in  the  male 
and  both  in  the  female  remain  concealed  in  a 
rudimental  state  within  the  maxillary  bones. 

The  cranium  in  the  genus  Hyperoodon,  which 
includes  the  Great  Bottle-noseWhale  of  Hunter, 
is  at  once  distinguishable  by  the  remarkable 
vertical  crest  which  rises  from  the  middle  of 
the  maxillary  bones,  the  contour  of  which  pro- 
cess descends  suddenly  behind,  but  extends 
more  gradually  and  obliquely  downwards  an- 
teriorly. The  lower  jaw  in  this  genus  has  two 
rudimental  teeth  at  its  anterior  part. 

Lastly,  in  the  Gangetic  Dolphin  (Plata- 
nista)  the  cranium  presents  a  marked  resem- 
blance to  that  of  the  Delphinorhynchus  in  the 
length  and  narrowness  of  the  rostrum,  and  in 
the  elevation  and  anterior  curvature  of  its  base; 
but  on  pursuing  the  comparison  in  detail,  the 
structure  and  composition  of  this  part  of  the 
skeleton  presents  several  fundamental  diffe- 
rences, which  at  the  same  time  indicate  an 
affinity  to  the  Cachalots  fPhyseter).  The 
most  striking  character  in  the  cranium  of  the 
Platanista  is  presented  by  the  maxillary  bones, 
which,  after  having  covered,  as  in  the  other 
Delphinidce,  the  frontal  bones  as  far  as  the 
temporal  cristae,  give  off  respectively  a  large 
osseous  expansion,  which  arches  forwards  and 
forms  a  capacious  vault  above  the  spouting 


CETACEA. 


567 


apparatus  of  the  nostrils.  In  order  to  consti- 
tute this  part,  one  of  the  processes  inclines 
towards  the  other,  so  as  almost  to  come  in 
contact  with  it  for  the  two  anterior  thirds  ;  but 
posteriorly  they  recede  from  one  another  to  give 
passage  to  the  blow-hole.  The  cavity  beneath 
this  singular  bony  pent-house  is  occupied  by 
an  interlacement  of  numerous  osseous  pro- 
cesses, and  by  a  close  and  hard  fibrous  sub- 
stance.* 

If  we  suppose  the  cranium  of  a  Dolphin 
to  be  proportionally  very  much  shortened,  the 
margins  of  the  rostrum  to  be  greatly  expanded 
and  raised,  so  as  to  render  its  superior 
surface  concave;  the  supra-frontal  portions 
of  the  maxillary  bones  to  be  much  developed 
and  the  margins  extended  upwards,  thus  form- 
ing an  immense  basin,  at  the  bottom  of  which 
lie  the  external  orifices  of  the  bony  nostrils ; 
if  also  the  occipital  crest  in  the  Dolphin  were 
raised  behind  the  maxillaries  so  as  to  aid  them 
in  the  formation  of  the  bony  cavity,  in  the 
basis  of  which  the  parietals  are  almost  con- 
cealed, we  should  then  have  the  skull  of  a 
Cachalot.  The  rostrum  in  the  Catodontidae,  not- 
withstanding its  immense  size,  is  formed  prin- 
cipally by  the  maxillary  bones,  as  the  inter- 
maxillaries  and  the  vomer  constitute  a  compa- 
ratively small  part  of  the  intermediate  portion. 
The  nasal  passages  extend  obliquely  from  below 
upwards  and  forwards,  but  are  of  very  unequal 
dimensions,  the  one  on  the  right  side  not 
having  one-fourth  the  breadth  of  that  on  the 
left.  A  corresponding  want  of  symmetry  is 
shown  in  the  nasal  bones  themselves,  and  the 
cranium  generally;  and  this  circumstance,  it 
may  be  remarked,  characterizes  in  a  greater 
or  less  degree  the  skull  in  all  the  Zoophagous 
Cetacea. 

The  skull  in  the  Whalebone-Whales  (Bala- 
nid<z)  is,  however,  the  most  symmetrical  in  its 
general  form;  it  is  characterized  by  the  great 
relative  predominance  of  the  facial  over  the 
cranial  portion,  by  the  narrowness  of  the  ros- 
trum, and  the  curvature  of  the  rami  of  the  lower 
jaw,  which  each  extend  outwards,  in  a  convex 
sweep,  far  beyond  the  sides  of  the  upper  max- 


illa, and  converge  to  the  symphysis,  but  with- 
out meeting  to  form  a  bony  union  at  their  ante- 
rior extremities. 

In  the  Mysticete,  or  common  Whalebone- 
Whale  (of  which  a  side  view  of  the  skull  is 
given  at)%.  249)  the  immense  maxillary  bones 
(a,  a)  are  compressed,  and  disposed  each  like 
an  expanded  arch  along  the  outside  of  the  in- 
termaxillaries  (b)  and  the  vomer;  their  inferior 
surface  has  two  facets  separated  by  an  interme- 
diate longitudinal  ridge,  to  the  sides  of  which 
the  plates  of  whalebone  or  baleen  are  attached 
(b,fig.  259).  The  intermaxillary  bones  are  also 
laterally  compressed,  and  diverge  from  each 
other  posteriorly  to  form  the  long  elliptical 
bony  out'et  of  the  nostrils;  this  orifice  is  com- 
pleted behind  by  the  nasal  bones,  which  are  of 
very  small  size,  and  are  partially  covered  by 
the  frontal  bones,  which  project  forwards  above 
them  in  the  form  of  two  small  points.  The 
tranverse  portions  of  the  frontal  (c)  and  max- 
illary (a*)  bones,  which  contribute  to  form  the 
orbits,  extend  obliquely  backwards :  the  tem- 
poral bone  (d)  is  of  an  irregular  quadrate 
form,  and  extends  much  further  backwards 
even  than  the  occipital  condyles.  The  occipital 
bone  (e)  advances  forwards  so  as  to  cover 
almost  all  the  upper  part  of  the  cranium, 
where  it  presents  a  general  convexity.  Each 
ramus  of  the  lower  jaw  (f)  is  convex  exter- 
nally, compressed  and  somewhat  trenchant 
both  at  the  upper  and  lower  margins.  The 
coronoid  process,  on  which  the  letter  is  placed, 
is  in  the  form  of  a  slightly  raised  obtuse  angle ; 
the  condyloid  process  (g)  forms  the  large  tube- 
rosity  behind.  It  is  articulated  to  the  glenoid 
cavity  by  a  mass  of  ligamentous  fibres,  and  not 
by  a  capsular  ligament  surrounding  a  synovia! 
cavity. 

The  vertebral  column  of  the  Cetacea  does  not 
differ  from  that  of  other  mammalia  except  in  the 
modifications  demanded  by  their  peculiar  mode 
of  existence.  The  cervical  vertebrae,  of  the 
normal  number  of  seven,  with  the  exception 
of  the  Manatee,  are  in  general  extremely  thin, 
and  though  in  some  species,  such  as  the 
Manatee,  the  Dugong  (k,  Jig.  246),  and  the 


Fig.  249. 


*  For  a  detailed  account  of  the  structure  of  the 
skull  in  this  singular  fresh-water  Cetacean,  see 
Cuvier,  Ossemens  Fossiles,  v.  pt.  i.  p.  298. 


Platanista,  they  are  found  free;  others,  as  the 
Dolphins  and  Porpesses,  have  the  first  two 
commonly  anchylosed  together.  In  the  Balae- 


568 


CETACEA. 


nopterae  the  dentata  is  anchylosed  at  its  upper 
part  to  the  third  cervical  vertebra.  In  the 
Cachalots  they  are  the  six  last  vertebrae  which 
are  thus  found  united  to  one  another,  and  in 
the  Whales,  properly  so  called,  or  Baltfnte,  all 
the  seven  are  anchylosed.  (See^g.  250.) 

Fig.  250. 


Fig.  252. 


Cervical  vertebree  of  a  Whale,  Balcena  Australit. 

The  dorsal  vertebrae  (%/g.246),  the  number 
of  which  varies  according  to  the  species,  are 
characterized  by  having  their  spinous  processes, 
bent  backwards,  elongated  from  the  first  to  the 
last,  and  equalled  in  length  by  the  transverse 
processes.  Moreover,  their  posterior  articu- 
lating processes  disappear  after  the  first  ver- 
tebra, and  the  anterior  ones  soon  cease  to  per- 
form the  functions  of  parts  concerned  in  the 
union  of  the  vertebras  to  one  another. 

In  Jig.  251,  which  represents  the  eleventh 
dorsal  vertebra  of  the  Cape  Whalebone  Whale, 
a  is  the  spinous ;  6,  6,  the  two  transverse, 
which  begin  to  lengthen  from  this  point  in  the 
succeeding  vertebrae ;  c,  c,  the  anterior  articu- 
lating processes. 

Fig.  251. 


Dorsal  vertebra  of  a  Whale. 

The  lumbar  vertebrae  (m,  Jig.  246),  the 
posterior  limit  of  which  it  is  difficult  to  deter- 
mine in  animals  devoid  of  pelvis,  have  their 
spinous  (a,  jig.  252)  and  transverse  processes 
(b)  very  long.  The  first  are  straight  and 
slightly  inclined  backwards. 

As  it  is  essential  that  the  Cetaceans  should 
have  the  posterior  part  of  their  vertebral  co- 
lumn left  free,  to  allow  of  the  vigorous  in- 
flexions of  the  tail  required  in  the  act  of 


Lumbar  vertebra  of  a  Whale. 


swimming,  none  of  the  vertebra?  are  anchy- 
losed together  or  encumbered  by  a  union  with 
posterior  extremities,  and  hence  there  are  none 
which  can  be  properly  termed  sacral,  unless 
we  regard  the  sacrum  as  represented  by  the 
single  vertebra,  ( n,  fig.  246,)  to  which,  in  the 
Dugong,  the  pelvic  bones  are  suspended.  The 
caudal  vertebrae  may  then  be  considered  to 
commence  from  this  point.  Most  of  these 
vertebrae  (o,  Jig.  246)  are  further  charac- 
terized by  the  chevron  bones,  (p,  Jigs.  246, 
253,)  which  at  first  are  strong  and  well  deve- 
loped, but  together  with  the  other  processes 
gradually  diminish  and  disappear  towards  the 
extremity  of  the  vertebral  column,  where  the 
centres  or  bodies  of  the  vertebrae  alone  appear, 
and  present  a  depressed  flattened  form  cor- 
responding to  the  horizontal  position  of  the 
caudal  fin,  which  characterises  these  air-breath- 
ing inhabitants  of  the  ocean. 

Fig.   253    represents   one   of   the  anterior 
caudal  vertebrae  of  the  Cape  Whale :  a  is  the 
spinous ;  b  the  transverse ;  c,  r ,  the  represen- 
tatives of  the  an- 


Fig.  253. 


Caudal  vertebra  of  a  Whale. 


terior  oblique  pro- 
cesses; p  the  in- 
ferior spinous  pro- 
cesses, or  chevron 
bones. 

To  bones  so  lit- 
tle mobile,  and  so 
rudimental  as  the 
vertebrae  of  the 
neck  in  Cetace- 
ans, muscles  pro- 
portionately de- 
veloped should 
correspond,  and 
such  in  fact  is 
the  case.  The 
cervical  muscles 
in  these  animals 
are  the  same 
in  number  as  in 
other  Mammals, 
but  their  short- 


CETACEA. 


569 


ness  and  thinness,  principally  in  those  at- 
tached to  the  atlas  and  the  axis,  are  extreme; 
and  although  those  which  proceed  from  the 
other  cervical  vertebrae  may  be  better  charac- 
terized, their  action,  nevertheless,  is  not  much 
more  extensive. 

The  muscles  of  the  back  present  no  other 
important  modifications  than  their  great  deve- 
lopment and  their  prolongation  even  upon  the 
coccygeal  vertebrae.  Thus  the  longisshnus  dorsi 
and  the  sacro-lumbalis  are  attached  anteriorly 
to  the  skull,  and  posteriorly  transmit  their  ten- 
dons, the  first  to  the  end  of  the  tail,  the  second 
to  all  the  transverse  processes  of  this  part  of 
the  spine,  associating  in  this  way  the  move- 
ments of  the  back  with  those  of  the  tail.  As 
to  the  muscles  peculiar  to  the  tail,  besides  those 
which  belong  to  this  organ  in  all  Mammals 
where  it  exists  as  a  moveable  organ,  there  are 
besides,  in  the  Cetaceans,  1st,  the  antagonists 
of  the  sacro-lumbalis  below  the  transverse  pro- 
cesses ;  2nd,  a  levator  cauda,  which  takes  its 
rise  above  the  five  or  six  dorsal  vertebrae,  under 
the  longissimus  dorsi,  and  often  in  this  part 
blends  with  it ;  it  then  extends  freely  as  far  as 
the  extremity  of  the  tail,  where  the  two  muscles 
unite  together  again  by  their  tendons ;  3rd,  a 
depressor  caud<e,  of  great  thickness,  which  pro- 
ceeds from  the  pectoral  region,  and  spreads  its 
tendinous  processes  upon  the  ribs,  distributes 
them  laterally  to  the  transverse  processes,  and 
below  to  be  inserted  into  the  chevron  bones 
along  the  two  posterior  thirds  of  the  tail ;  4th,  a 
muscle  which  comes  from  the  rudimental  bones 
of  the  pelvis,  arid  is  inserted  into  the  chevron 
bones  of  the  anterior  portion  of  the  tail ;  5th, 
the  great  rectl  muscles  and  the  obliqui  ascen- 
dentes,  which,  proceeding  from  the  abdomen, 
attach  themselves  behind  to  the  sides  of  the 
base  of  the  tail. 

It  is  in  consequence  of  this  great  aggre- 
gation of  muscles,  which  are  developed  in 
unexampled  proportions  as  compared  with 
other  Mammals,  that  the.  tail  of  the  Cetaceans 
acquires  the  prodigious  strength  which  it  pos- 
sesses, and  by  means  of  which  these  gigantic 
animals  propel  themselves  widi  so  much  faci- 
lity and  impetuosity  through  the  water,  and 
so  readily  ascend  to  the  surface  to  respire, 
and  again  seek  protection  in  the  deep  abysses 
of  the  ocean. 

The  sternum  (q,fg.  246)  is  short  and  large. 
In  the  Dugong  it  is  composed  of  five  pieces ; 
in  the  Dolphin,    the  Porpesse,  and  the  Pla- 
tanist,  it  is  generally  composed  of  only  three ; 
in  the  Whales  it  consists  of  but  one.     In  the 
subjoined   figure    (Jig-  254)   from   the  Bal<s- 
noptera  Boops,   the 
Fig,  254.  sternum    is    deeply 

notched  behind,  and 
has  a  large  ridge  on 
its  exterior  or  under 
surface. 

The  ribs  of  the 
Cetaceans  arechiefly 
remarkable  for  their 
great  curvature,  but 
differ  in  their  rela- 
tive length,  thickness,  and  mode  of  connection. 

VOL.  I, 


Their  thickness  and  the  density  of  their  tex- 
ture is  most  remarkable  in  the  Herbivorous 
species,  especially  in  the  Manatee.  In  the 
Dugong,  which  has  eighteen  pairs  of  ribs 
(r,  r,  Jig.  246),  only  the  first  three  have  car- 
tilages which  join  the  sternum.  In  the  /)<•/- 
phinidte  the  first  pair  of  ribs  are  articulated  at 
their  sternal  extremities  to  the  anterior  angles 
of  the  first  bone  of  the  sternum ;  the  second 
pair  join  the  sternum  between  the  first  and 
second  bones ;  the  third  between  the  second 
and  third,  and  the  fourth,  fifth,  and  in  some 
species  the  sixth  pairs  of  ribs  are  joined  to  the 
third  bone  of  the  sternum;  the  sternal  portions 
of  these  ribs  are  ossified.  The  anterior  ribs 
are  articulated  at  first  by  a  head  to  the  ver- 
tebral centres,  and  by  a  tubercle  to  the  trans- 
verse processes  ;  but  as  they  extend  backwards 
the  head  disappears,  and  the  ribs  are  attached 
only  to  the  extremities  of  the  transverse  pro- 
cesses. 

In  the  Balanida  the  first  pair  of  ribs  are 
remarkable  for  their  great  breadth,  especially 
at  the  sternal  extremity,  and  these  alone  join 
the  sternum.  In  the  Baltena  Cupensis  the  two 
first,  as  well  as  the  four  last  pairs  of  ribs,  are 
joined  only  to  the  transverse  processes  of  the 
vertebrae. 

The  depressors  and  elevators  of  the  ribs  ap- 
pear to  possess  nothing  particular,  and  the 
same  may  be  said  of  the  diaphragm  and  the 
muscles  of  the  abdomen  ;  but  in  regard  to  the 
movements  of  these  parts,  we  must  remember 
what  M.  Mayer  says  of  the  muscular  fibres, 
which  encircle  closely  the  lungs,  and  which 
take  part  in  the  actions  of  inspiration  and 
expiration. 

[Mr.  Hunter  observes  that,  "  as  the  ribs  in 
this  tribe  do  not  completely  form  the  cavity 
of  the  thorax,  the  diaphragm  has  not  the  same 
attachments  as  in  the  Quadruped,  but  is  con- 
nected forwards  to  the  abdominal  muscles, 
which  are  very  strong,  being  a  mixture  of 
muscular  and  tendinous  parts.  The  position 
of  the  diaphragm  is  less  transverse  than  in  the 
Quadruped,  passing  more  obliquely  back- 
ward and  coming  very  low  on  the  spine, 
and  high  up  before,  which  makes  the  chest 
longest  in  the  direction  of  the  animal  at  the 
back,  and  gives  room  for  the  lungs  to  be  con- 
tinued along  the  spine."] 

The  anterior  members  in  the  Cetaceans  do 
not  essentially  differ  from  those  of  the  other 
Mammalia,  but  they  undergo,  in  these  animals, 
very  great  modifications. 

In  the  shoulder  they  are  entirely  devoid 
of  clavicles.  Their  scapula  is  very  large  in 
general,  but  varies  in  this  respect  according  to 
the  species.  In  the  Herbivorous  Cetaceans,  as 
the  Dugong  (.s,  Jig.  246),  the  anterior  angle  is 
rounded,  the  posterior  is  extended  backwards, 
and  the  posterior  margin  or  costa  is  concave. 
The  spine  is  prominent,  and  so  placed  as 
to  divide  the  dorsum  of  the  scapula  into  a 
supra-spinal  and  infra-spinal  depression.  The 
acromion  is  pointed,  but  much  less  elongated 
in  the  Dugong  than  in  the  Manatee.  The 
coracoid  process  is  also  more  pointed  in  the 
Dugong. 

2  P 


570 


CETACEA. 


In  the  Zoophagous  Cetaceans  the  spine  of 
the  scapula  does  not  project  much.  The 
supra-spinal  fossa  is  reduced  to  a  mere  groove 
in  the  common  Dolphin,  and  entirely  dis- 
appears in  the  Gangetic  species  ( Platanista)  ; 
the  coracoid  process  does  not  exist  in  this  last 
dolphin ;  and  the  same  ahsence  is  found  in 
the  ttal&nidtf,  whilst  it  is  seen  in  the  common 
Dolphin  and  the  Cachalot.  Lastly,  the  acro- 
mion  appears  always  to  exist,  but  with  a 
different  development,  in  different  species. 
In  the  scapula  of  the  Whalebone  Whale  (A, 
jig.  255)  it  is  marked  a.  The  articular  or 

Fig.  255. 


Bones  of  the  anterior  fin  of  a  Whale, 
Balcena  Mysticetus. 

glenoid  cavity  (6)  is  proportionally  larger  in 
this  species  than  in  the  Spermaceti  Whale. 
The  muscles  of  this  part  of  the  anterior  mem- 
ber present  some  remarkable  modifications,  but 
with  which  we  are  only  acquainted  as  they 
exist  in  the  common  Dolphin.  Thus  the 
serratus  magnus  does  not  extend  as  far  as  the 
cervical  vertebrae,  and  ends  at  the  ribs ;  the 


pectoralis  minor,  instead  of  descending  on  the 
ribs,  is  directed  towards  the  anterior  extremity 
of  the  sternum. 

The  rhomboideus  (a,  fig.  256)  is  not  attached 
to  the  ridge  of  the  spine,  but  extends  along  the 
superior  edge  of  the  scapula;  the  trapezius 
covers  the  scapula  and  has  no  clavicular  pro- 
longation. 

The  levator  scapula  (b.fig.  256)  is  attached 
to  the  broad  transverse  process  of  the  first 
vertebra,  and  spreads  itself  over  all  the  ex- 
ternal surface  of  the  scapula. 

The  rest  of  the  anterior  member  is  com- 
posed of  the  humerus,  the  radius,  the  carpus, 
the  metacarpus,  and  the  phalanges. 

Ill  the  Dugong  the  humerus  (t,  Jig.  246) 
is  much  shorter  and  thicker  than  in  the  Ma- 
natee, and  the  deltoid  ridge  is  more  prominent. 
In  the  true  Cetacea  the  humerus  is  always 
very  short.  In  the  Whalebone  Whale  (B, 
fig.  255)  its  length  is  scarcely  double  its 
breadth  ;  its  head  is  hemispherical  and  almost 
parallel  to  the  axis  of  the  bone.  The  lower 
extremity  is  divided  into  two  planes  slightly 
inclined  for  the  ulna  and  radius. 

The  cubitus  and  the  radius  (v)  are  also  very 
short,  and  are  anchylosed  (u,fig.  246)  together 
at  both  extremities  in  the  Manatee  and  the 
Dugong,  but  they  retain  in  these  Cetaceans 
the  rounded  form  which  is  peculiar  to  them  in 
the  other  Mammalia.  In  the  spouting  Ceta- 
ceans they  are  compressed,  and  are  united  by 
means  of  fibro-cartilage  with  the  humerus  and 
the  carpus.  The  olecranon  varies  in  size. 
In  the  great  Whale  it  rises  in  but  a  small  de- 
gree, while  in  the  Spermaceti  Whale  it  is  de- 
veloped in  the  form  of  a  hook.  The  radius 
(C>fig-  255),  which  is  broader  than  the  ulna 
(D,  fig.  255),  is  dilated  at  its  lower  ex- 
tremity. 

The  bones  of  the  carpus  are  very  much 
flattened,  and  of  an  hexagonal  form ;  they  are 
less  in  number  than  in  Man,  but  the  number 
varies  according  to  the  species.  The  Manatee 
has  six,  the  pisiform  being  wanting.  The 
Dugong  has  four  (iv,  fg.  246"),  of  which  two 
are  in  the  first  row  corresponding  respectively 
to  the  radius  and  ulna,  and  two  in  the  second 
row,  the  external  one  supporting  the  metacar- 
pal  bones  of  the  pollex  and  index,  the  internal 
bone  supporting  the  medius  and  annularis ; 
the  ulnar  or  little  digit  is  supported  by  the 
ulnar  carpal  bones  of  both  the  first  and  second 
row.  The  pollex  (x,fig.  246)  is  reduced,  as 
in  the  Manatee,  to  a  small  pointed  meta- 
carpal  bone.  The  common  Dolphin  has  only 
five  metacarpal  bones ;  the  Whale  has  seven  : 
of  these  four  are  in  the  first  row,  and  three  in 
the  second  (E,  fig.  255).  The  metacarpals 
( _F,  fig.  255)  are  five  in  number,  much  flat- 
tened, and  have  the  general  form  of  phalanges. 
The  phalanges  in  the  Zoophagous  Cetaceans 
partake  of  the  flattened  form  of  the  bones  of 
the  metacarpus.  Their  number  increases  in 
each  finger,  comparatively  with  the  normal 
number,  sometimes  very  much  so ;  and  in 
many  cases  there  are  some  which  remain 
cartilaginous.  The  pollex  (G  1,  fig.  255) 
in  the  great  Whale  has  two  bones ;  the  index 


CETACEA. 


Fig.  256. 


Muscles  of  the  anterior  Jin  of  a  Dolphin. 

a.  Rhomboideus.  e.  Sterno-mastoideus. 

b.  Levator  scapulae.  /.  Costo-humeralis  or  latissimus  dorsi. 

c.  Infra-spinatus.  g.  Portion  of  pectoral. 

d.  Humero-mastoideus.  h.  Splenius. 


(2)  four,  the  digitus  medius  (3)  five,  the  annu- 
laris  (4)  four,  and  the  digitus  parvus  (5)  three 
bones ;  all  are  terminated  by  a  cartilaginous 
dilatation :  they  form  collectively  a  large  and 
short  paddle,  obliquely  rounded. 

The  muscles  which  characterize  the  arm  of 
the  Mammalia  exist  generally  also  in  the 
Dolphin,  and  doubtless  in  the  other  Cetaceans, 
but  with  modifications  which  have  not  been  so 
satisfactorily  described  as  could  be  wished. 
The  great  pectoral  muscle  (a  part  of  which  is 
seen  at  g,  fig.  256)  presents  the  sternal  portion, 
which  is  called  the  musculus  communis,or  mus- 
cle common  to  the  two  arms.  The  latis- 
simus dorsi  (f,flg-%56}  is  represented  by  a  little 
muscle,  the  digitations  of  which  are  attached 
to  the  ribs ;  the  supra-spinatus  and  infra- 
spinatus  are  nearly  of  equal  size,  but  the  sub- 
scapularis  is  very  large.  The  coraco-brachudis 
is  very  short.  The  muscles  of  the  other  parts 
of  the  arm,  that  is,  of  the  fore-arm  and  hand, 
appear  in  a  rudimental  state,  and  seem  to 
exist  less  on  account  of  the  movements  of  the 
parts  to  which  they  are  attached,  than  to  shew 
the  analogy  of  the  anterior  members  of  the 
Cetaceans  with  those  of  other  Mammalia. 

[In  our  dissections  of  the  common  Porpesse 
we  have  found  the  supra-spinalis  of  small  size, 
corresponding  to  the  size  of  the  supra-spinal 
fossa.  It  is  covered  by  the  deltoid  muscle  (i). 
The  infra-spinatus  (c)  is  consequently  of  much 
larger  size,  but  is  a  thinner  muscle:  behind 
this  muscle  is  seen  the  teres  major  ( k )  and 
minor  (/).] 

As  we  have  already  said,  the  posterior  extre- 
mities are  wanting ;  all  that  remains  of  them  are 
the  rudiments  of  a  pelvis.  These  rudiments 
are  found  in  the  Dugong  to  be  composed  of 
two  pairs  of  bones  (y,  Jig.  246)  united  two 
and  two,  and  end  to  end  by  a  cartilage,  and 


Fig.  257. 


571 

attached  by  a  carti- 
lage also  to  one  of 
the  vertebrae.  In  the 
Dolphins  they  con- 
sist of  two  little, 
long,  thin  bones 
which  are  lodged  in 
the  flesh,  one  to  the 
right  and  the  other 
to  the  left  of  the 
anus.  In  the  Whales, 
at  the  extremity  of 
each  of  these  bones 
(a,a,fig  257), which 
are  regarded  as  ilia, 
a  second  (6)  is  found 
articulated,  smaller, 
and  curved ;  the  con- 
vexity of  which  is 
external,  and  might 
represent  a  pubis,  or 
anischion;  it  seems 
to  correspond  to  the 
second  of  these  bones 
in  the  Dugong. 

We  perceive  that 
the  internalconslruc- 
tion  of  the  organs  of 
movement  in  the  Ce- 
taceans does  nol  vary 
in  the  different  spe- 
cies except  by  mo- 
difications the  im- 
portance of  which 
we  are  not  able  to 
appreciate.  The  dif- 
ferences in  their 
exterior  structure, 
moreover,  do  not  ap- 
pear to  exercise  any 
influence  over  their 
mode  of  living;  for 

the  chief  of  these  consists  in  the  Manatee 
having  nails  to  the  ends  of  its  pectoral  fin, 
which  correspond  to  the  fingers,  of  which  it 
is  in  part  composed  ;  and  in  its  tail  being  oval 
instead  of  being  extended  laterally  into  two 
wings. 

We  have  in  no  way  considered  as  forming 
part  of  the  organs  of  movement,  the  protu- 
berances which  are  seen  upon  the  back  of 
some  species  of  spouting  Cetaceans,  some- 
times in  the  form  of  a  hump,  and  sometimes 
like  a  fin,  more  or  less  elevated.  These  pro- 
tuberances, in  fact,  are  nothing  more  than 
simple  gibbosities,  simple  prolongations  of  the 
skin,  filled  with  dense  cellular  tissue  and  fat, 
and  resembling  more  or  less  a  fin,  but  devoid 
of  any  independent  movement,  and  without  any 
direct  connection  either  with  the  vertebrae  of 
the  back  or  with  the  muscular  system. 

Digestive  organs.  —  The  alimentary  appa- 
ratus is  one  of  those,  which,  in  many  of  its 
parts,  presents  the  most  important  modifica- 
tions in  the  Cetaceous  Order. 

The  three  genera  into  which  the  Herbivorous 
Cetaceans  are   divided,    are  characterized  by 
three  systems  of  dentition  fundamentally  dif- 
ferent.   The  Manatees  have  molares  with  dou- 
2  P  2 


Pelvis  of  the  Mysticete 
Whale. 


572 


CETACEA, 


ble  or  triple  ridges,  and  with  the 
root  distinct  from  the  crown,  pre- 
senting a  remarkable  resemblance 
to  those  of  some  of  the  Pachy- 
derms, as  the  Hippopotamus.  The 
Dugongs  have  simple  elliptical 
molares,  the  crown  of  which,  before 
it  is  worn,  presents  two  slight  fur- 
rows, which  are  entirely  effaced 
by  age.  They  are  without  fangs, 
properly  so  called ;  and  in  the  up- 
per jaw  are  found  two  long  tusks, 
of  which  the  other  Cetaceans  of 
this  family  are  destitute.  The 
Rytintz  have  no  molares  at  all;  these  teeth 
are  replaced  by  a  horny  plate  in  the  middle 
of  each  jaw,  a  structure  which  seems  to  connect 
these  animals  with  the  Whalebone  Whales. 

The  tongue  is  short  and  but  little  susceptible 
of  movement. 

The  os  hyoides  is  characterized  in  the  Cetacea 
chiefly  by  the  slight  degree  or  total  absence 
of  connection  with  the  larynx,  resulting  from 
the  elevated  position  of  this  organ  required  by 
its  peculiar  relations  with  the  posterior  nares. 

In  the  Herbivorous  order  the  Dugong  pre- 
sents a  simple  form  of  the  os  hyoides;  the 
posterior  cornua  soon  anchylose  with  the  body, 
but  send  no  ligament  to  the  thyroid  cartilage 


Fig.  259. 


Tongue  and   Baleen-plates  of   the   Piked   Whale, 
Balcenoptera  Boops.* 

The  genio-glossi  pass  backwards  and  inwards 
from  the  anterior  contour  of  the  lower  jaw. 

The  tongue  itself  corresponds  to  the  form 
of  the  space  included  by  the  rami  of  the  lower 
jaw,  and  is  consequently  of  great  size  in  the 
Cachalots  and  Balamida,  rising  in  the  latter 
like  an  immense  cushion  (a,  Jig.  259),  into 
the  space  between  the  laminae  of  baleen  (6), 
and  affording  a  great  quantity  of  the  finest  oil. 
In  the  figure  it  is  represented  in  the  Piked 
Whale,  but  probably  preternaturally  enlarged 
and  raised  by  the  extrication  of  gas  caused  by 
putrefaction.  It  is  thick,  and  its  free  extremity 
is  generally  short,  but  this  is  less  remarkable 
in  the  Phytophaga  than  in  the  Zoophuga.  In 


The  anterior  cornua  generally  remain  cartila-    the  Dugong  (jig.  260)  the  upper  surface  of 

i/»  .1  ••  /»  •  i 4-Vtsi  rA^  +  ^.vi,-,*.  -»-vov«4-   f\f   4-V»£*    fr\nmio  ( ft\  l^   HPQPt  with 


ginous,  and  form  the  medium  of  union  be- 
tween the  body  or  basi-hyal,  and  the  large  and 
long  styloid  processes.  In  the  Delphinida  the 
body  and  posterior  cornua  of  the  hyoid  bone 
are  of  a  flattened  form.  In  the  Balanidte,  as 
the  Piked  Whale  or  Balaenoptera,  the  body 
(a,  jig.  258)  is  a  cylindrical  bone,  extended 

Fig.  258. 


the  anterior  part  of  the  tongue  (a)  is  beset  with 
cuticular  spines,  and  on  each  side  of  its  basis 
there  is  a  remarkable  horny  retroverted  pointed 
process  (6,  6). 


Fig.  260. 


Hyoid  bones  of  the  Piked  Whale. 

transversely,  and  is  slightly  curved  backwards 
and  upwards;  its  middle  portion  supports  an- 
teriorly two  processes  (6,  6)  resembling  the 
base  of  the  anterior  cornua  in  the  Ruminants  ; 
besides  these  there  are,  in  this  genus,  two 
rounded  tubercles  on  the  posterior  margin  op- 
posite these  processes.  The  styloid  bones 
(c,  c)  are  cylindrical  and  slightly  curved  in 
two  directions ;  they  are  joined  by  cartilage 
on  each  side  to  the  occipital  protuberance 
which  represents  the  mastoid  process. 

The  muscles  which  protrude  and  retract  the 
tongue  are  extremely  simplified  in  the  Ce- 
taceans ;  the  retractors  are  represented  by  a 
single  pair,  analogous  to  the  stylo-hyoidei,  the 
fibres  of  which  pass  from  the  posterior  margin 
of  the  stylo-hyal  bones  to  the  body  of  the 
hyoid.  The  stylo-glossi  pass  from  the  anterior 
and  superior  margin  of  the  styloid  process  to 
their  insertion.  The  hyoglossi  arise  from  the 
middle  of  the  convexity  of  the  os  hyoides. 


Tongue  of  tJte  Dugong. 

In  the  Porpesse  the  surface  of  the  tongue  is 
soft  and  smooth,  and  very  flat  superiorly ;  the 
anterior  margin  is  fringed  by  a  number  of  short 
irregular  processes  (a,  Jig.  265). 

The  salivary  glands  are  reduced  to  the  most 
rudimental  condition. 

In  the  Phytophagous  Cetaceans  the  stomach 
is  separated  into  two  portions  (Jig.  261);  one, 
the  cardiac  (a),  very  large,  the  other,  the 
pyloric  (6),  of  narrower  calibre,  by  a  contrac- 
tion (c)  giving  origin  to  two  prolongations 
(d,  d),  which  are  tubiform  in  the  Dugongs, 
and  of  a  pouch-like  form  in  the  Manatees. 

In  both  species  there  is  a  gland  at  the 
cardiac  extremity  of  the  stomach  (c),  which  in 
the  Dugong,  Sir  Everard  Home  (from  whose 
memoir  the  figure  subjoined  is  taken)  describes 
as  "  forming  a  round  mass,  as  in  the  Beaver. 
The  orifices  of  these  glands  are  small,  and 

*  From  Fr.  Cuvier,  Cetacea,  pi.  20.    g 


CETACEA. 


573 


Fig.  261. 


Stomach  of  the  Dugong. 


covered  over  with  a  membranous  bag,  which 
has  only  one  large  aperture.  The  glandular 
mass  is  divided  into  two  portions."*  Thus  the 
stomach  of  the  Dugong  presents  peculiarities 
which  are  met  with  singly  in  animals  of  the 
Cetaceous,  Pachydermatous,  and  Rodent  Or- 
ders. Like  the  stomach  of  the  Whale  it  is 
divided  into  distinct  compartments  ;  like  the 
stomachs  of  the  Hippopotamus  and  Peccary 
it  has  ccecal  pouches  superadded  to  and  com- 
municating with  it;  and  like  those  of  the  Dor- 
mouse and  Beaver  its  cardiac  compartment  is 
provided  with  a  glandular  apparatus  :  (fis  the 
oesophagus,  g  the  intestine.) 

The  ccecum  is  simple  and  cordiform  in  the 
Dugong  (Jig.  262),   but  is  of  more  irregular 

Fig.  262. 


Caecum  of  the  Dugong. 

figure  and  bifurcated  in  the  Manatee.  The  Ry- 
tina  appears  also  to  possess  a  stomach  divided 
into  two  portions,  of  which  the  cardiac  is  also 
larger  than  the  pyloric ;  and  it  has  a  very  large 
ca-cum,  divided  on  its  internal  surface  into 

*  Phil.  Tians.  1820,  p.  317. 


numerous  cells.  A 
gland, remarkable  for 
its  size,  is  also  found 
in  the  first  portion  of 
the  stomach  of  this 
species.  No  sub- 
stances but/i/r*  have 
ever  been  found  in 
the  alimentary  canals 
of  these  animals. 

The  Zoophagous 
Cetaceans  present 
still  greater  differ- 
ences in  theiralimen- 
tary  organs  than  the 
Phytophaga.  In  the 
Dolphins  the  teeth, 
which  are  generally 
simple  and  conical, 
or  compressed  in 
both  jaws,  vary  con- 
siderably in  number, 

and  often  remain  concealed  in  a  rudimen- 
tary state  in  the  gums.  In  the  Cachalots 
they  are  only  found  in  the  lower  jaw;  are 
simple  and  oviform ;  and  their  number  ap- 
pears to  be  in  no  way  certain.  The  Whales 
have  no  true  teeth,  but  at  each  side  of  their 
palate  grow,  transversely,  horny  plates,  named 
baleen  (the  whalebone  of  commerce),  pro- 
vided on  their  inner  edges  with  fringe-like 
beards,  amidst  which,  as  in  the  meshes  of  a 
net,  the  animals  which  form  their  food  are 
retained. 

[The  structure,  forms,  and  disposition  of  the 
teeth  having  been  given  in  the  characters  of 
the  different  genera  of  Cetacea,  we  have  here 
only  to  add  a  few  words  on  the  subject  of  the 
baleen-plates  which  form  their  substitutes  in 
the  family  of  Balaenidae.  Each  of  these  plates 
consists  of  a  central,  coarse,  fibrous,  and  two 
exterior  or  lateral  compact  layers;  the  first 
extends  beyond  the  latter,  so  that  the  plate 
terminates  at  its  lower  or  free  extremity  in  a 
fringe,  and  in  looking  upwards  into  the  mouth 
of  a  Whale  when  all  the  baleen-plates  are  in 
situ,  only  their  fringed  extremities  are  seen. 

The  base  of  each  baleen-plate  has  a  conical 
cavity,  which  is  fixed  upon  a  pulp  of  a  cor- 
responding form,  buried  deeply  in  the  firm 
vascular  substance  of  the  gum  which  covers 
the  under  surface  of  the  maxillary  and  inter- 
maxillary bones;  the  sides  of  the  base  of  the 
baleen-plate  are  firmly  attached  to  white  horny 
laminae  of  the  gum,  which  are  reflected  from 
one  plate  to  another,  and  from  which  the  ex- 
ternal compact  layers  of  the  baleen  are  con- 
tinued :  the  pulp  appears  to  be  subservient  to 
the  secretion  of  the  central  coarse  fibrous  part 
alone.] 

Nothing  can  differ  more,  or  indeed  be  more 
contradictory  than  the  descriptions  which  have 
been  given  of  the  stomachs  of  the  Zoophagous 
Cetaceans.  In  many  of  the  species  the  struc- 
ture of  this  part  is  unknown.  It  has  been 
more  or  less  fully  described  in  the  Delphino- 
hynchus  micropterm,  the  common  Dolphin, 
11 "  Small  Bottle-nose  (Delphinus  Tursio), 
common  Porpoise,  the  Grampus,  the 


the 
the 


674 


CETACEA. 


PhocfBna   globiceps,    the    carinated   Porpoise, 
the  Beluga,   the  Platanist,    the  Narwhal,  the 
Great   Bottle-nose    or    Hyperoodon,    and  the 
Piked  Whale  (Balanoptcra) .  There  is  no  doubt 
that  the  stomachs  of  all  these  animals  are  very 
complicated ;   and  although   it  may  be  more 
than  probable  that  they  do  not  resemble  each 
other  in  their  composition,  it  is  to  be  presumed, 
however,  that  it  is  to  their  complication  we  must 
attribute  the  essentially  different  descriptions 
which   have  been   put  forth   on  this    subject. 
What  authorizes  this  supposition    is  the    di- 
versity  of  opinions   which   exists  relative   to 
the  number  of  the  stomachs  of  the  common 
Dolphin     and     common      Porpoise,      some 
counting  only  three,   others  four,  others  five, 
and  others  six,    &c.     Now  it  is  certain  that 
these  differences  of  number  proceed   simply 
from  the  manner  in  which  this  organ  is  viewed. 
When  it  is  only  judged  of  by  its  exterior,  and 
its  globulous  parts  alone  are  called  stomach, 
only  three  or  four  can  be  reckoned ;  and  then 
the   more  or  less  tubular  passages,    situated 
amongst  those  more  or  less  spherical  cavities, 
are  considered    as    mere   intercommunicating 
canals.     But  if  the  interior  of  these  stomachs 
be  studied,  it  is  seen  that  several  amongst  them 
have  a  special  organization,  and  are  separated 
from  one  another  by  small  openings,  which  do 
not  invariably  establish  a  direct  communica- 
tion between  them  :  hence  the  tubular  parts 
cannot  be  considered  as  simple  passages,  but 
must    necessarily   be    admitted    as    essential 
parts  of  the  stomach,   which,  like  the  others, 
impress  their  peculiar  action  upon  the  food. 
It  has  also  been  the  case  that  the  dilated  sac 
into  which  the  biliary  and  pancreatic  juices 
are  poured,  has  not  been  admitted  as  belong- 
ing to  the  stomach  ;  but  besides  its  not  being 
without  example  that  in  Mammalia  the  bile 
may  be  poured  immediately  into  the  stomach, 
the  difference  in  the  nature  of  the  membranes 
ought  to  suffice  for  deciding  whether  the  part 
which  receives  these  secretions  belongs  or  not 
to  the  duodenum.     Now  in  the  Dolphins  it  is 
evidently  at  the  termination  of  the  last  stomach 
that  their  duct  opens.     In  this  state  of  things 
it  is  impossible  to  decide  with   precision  in 
what  particulars  the  Zoophagous  Cetaceans  differ 
from  one  another  in  the  structure  of  the  sto- 
mach.     It  appears,  however,  that  this  organ 
in  the  common  Dolphin,  the  common  Porpoise, 
the  Globiceps,  and  the  Platanist,  is  formed  upon 
the  same  type,  and  is  composed  of  five  parts  ; 
and  if  they  differ  one  from  another,  it  is  only 
by  modifications  of  secondary  importance.     If 
to  these  facts  we  add  what  Meckel  states  re- 
specting the  Narwhal,  in  which  he  recognizes 
five  stomachs,  and  what  Hunter  says  of  the 
Grampus  and  Piked  Whale,  in  which  he  like- 
wise found  five,  we  have  three  species  more 
to  add  to  the  first.     In  fact,  when  we  consider 
that  only  three  or  four  stomachs  have  been  re- 
cognized  in  the  Carinated  Porpesse  and  the 
Beluga,  which  are   true  Phoctencz,    and   that 
Baussard  saw  three,  and  Hunter  seven  in  the 
Hyperoodon    (Great  Bottle-nose    Whale),  we 
believe  ourselves  authorized  in  thinking  that 
these  differences    depend    entirely   upon,  the 


manner  in  which  this  organ  is  viewed,  and  we 
consider  it  very  probable  that  the  number  of 
stomachs  in  these  Cetaceans,  as  in  the  others, 
is  five.  However,  from  this  small  number  of 
facts,  and  from  all  the  conjectures  with  which 
we  have  been  obliged  to  approach  the  subject, 
we  shall  draw  no  precise  conclusion  as  to  the 
structure  which  may  be  common  to  the  Zoo- 
phagous Cetaceans.  But  this  undoubted  great 
complication  of  the  stomach  in  animals  which 
are  nourished  with  the  most  animalized  food, 
is  an  anomaly  the  cause  of  which  it  would  be 
very  important  to  investigate  ;  for  from  the 
ascertained  facts  which  we  have  to  reason  from, 
we  are  not  led  by  any  analogy  to  an  explanation 
of  this  subject. 

[In  our  examinations  of  the  stomach  of  the 
Porpesse  (fig.  263),  we  have  not  been  able  to 

Fig.  263. 


Stomach  of  the  Porpesse. 

distinguish  more  than  four  compartments. 
This  complex  digestive  organ,  besides  the 
structure  of  the  internal  surface,  differs  from 
that  of  the  Ruminant  Animals  in  the  compara- 
tively small  size  of  the  first  cavity,  and  the  mode 
of  inter-communication  of  the  other  compart- 
ments, which  succeed  one  another,  and  are 
not  appended  to  the  extremity  of  the  oesopha- 
gus :  instead,  therefore,  of  the  oesophagus 
communicating  with  all  the  four  cavities,  it 
opens  only  into  the  first,  and  consequently  no 


CETACEA. 


575 


rumination  can  take  place.  The  first  cavity 
is  continued  in  the  same  line  with  the  oesopha- 
gus, having  the  same  structure,  and  not  being 
divided  from  it  by  any  sensible  constriction ; 
its  commencement  is  indicated  by  the  orifice 
leading  into  the  second  stomach,  beyond  which 
orifice  it  is  continued  in  the  form  of  a  dilated 
ovate  cavity  (a).  It  is  lined  with  a  cuticle, 
and  its  inner  surface  is  beset  with  small  rugae. 
A  number  of  large  irregular  projections  sur- 
round the  aperture  leading  to  the  second  ca- 
vity, and  are  calculated  to  prevent  the  passage 
into  the  second  of  any  substances  save  such 
as  are  of  very  small  size.  Notwithstanding 
the  nature  of  the  lining  membrane  the  di- 
gestive processes  are  considerably  advanced 
in  this  cavity,  which  does  not  act  simply  as  a 
reservoir.  It  is  probable  that  the  secretion  of 
the  second  stomach,  which  is  highly  glandular, 
regurgitates  into  the  first  and  assists  in  pro- 
ducing the  dissolution  of  the  carneous  parts 
of  the  fishes,  the  remains  of  which  are 
usually  found  in  it.  The  thick  cuticular 
lining  terminates  abruptly  at  the  small  ori- 
fice leading  into  the  second  stomach  (b). 
The  interior  of  this  cavity  presents  a  series  of 
close-set  thick  longitudinal  wavy  rugae,  laterally 
indented  into  one  another.  The  internal  layer 
is  thick  and  of  a  peculiar  structure :  according 
to  Sir  David  Brewster,  "  it  seems,  in  its  wet 
state,  to  consist  of  tubes  or  fibres  perpendicu- 
lar to  the  two  membranes  which  inclose  them, 
and  the  upper  surface  of  one  of  the  membranes 
is  covered  with  hollows  or  depressions  corres- 
ponding with  the  extremities  of  the  tubes  or 
fibres.  A  more  minute  examination,  conducted 
in  a  different  way,  proves  these  perpendicular 
portions  to  be  tubes.  In  order  to  dry  it,  1 
pressed  it  between  folds  of  paper,  and  the  effect 
of  the  compression  was  to  press  together  nearly 
all  the  tubes,  and  make  the  whole  one  dense 
mass,  of  a  dark  brown  colour;  but  when  it  be- 
came dry  and  slightly  indurated,  I  drew  it 
out  as  if  it  had  been  India-rubber,  and  the 
tubes  opened,  and  the  mass  became  white." 

The  membrane  next  the  cavity  of  the  sto- 
mach is  perfectly  smooth ;  the  one  external 
to  the  fibres  is  a  vascular  and  cellular  tunic, 
and  is  inverted  by  the  layer  of  muscular  fibres 
continued  from  the  preceding  cavity.  The 
communication  with  the  third  stomach  is  near 
the  lower  end  of  this  cavity.  The  third  com- 
partment is  a  small  round  vascular  cavity,  into 
which  the  second  opens  obliquely  :  it  is  lined 
by  a  smooth  and  simple  villous  tunic.  It  is 
not  visible  exteriorly,  and  does  not  exceed  an 
inch  in  length  in  the  Porpesse,  but  in  the 
Hyperoodon  is  about  five  inches  long.  The 
fourth  cavity  (c,  c)  is  long  and  narrow,  and 
passes  in  a  serpentine  course  almost  like  an 
intestine;  the  internal  surface  is  smooth  and 
even,  but  villous.  It  opens  on  the  right  side 
into  the  duodenum  (d},  which  is  much  dilated, 
and,  as  in  the  human  subject,  is  without  valvulae 
conniventes  at  its  commencement.  The  pylo- 
rus is  a  smaller  opening  than  that  between  the 
third  and  fourth  cavities.] 

Some  authors  speak  affirmatively  of  a  con- 
siderable bladder,  which  in  the  Rorquals,  after 


death,  comes  up  into  the  mouth  and  forces  the 
two  jaws  asunder.  Now  what  is  the  nature  of 
this  vesicular  mass,  of  which  other  authors  say 
nothing  ?  To  what  organic  system  does  it  be- 
long ?  This  has  never  been  made  a  subject  of 
enquiry.  It  has  been  considered  as  belonging 
to  the  respiratory  system,  or  as  an  air-bladder 
analogous  to  that  offish.  Is  it  not  more  proba- 
bly a  portion  of  the  stomach  distended  by  the 
gases  formed  there  ? 

In  general  the  Spouting  Whales  have  no 
ccecum.  However,  a  trace  of  this  gut  has 
been  found  in  an  oval  elevation  in  the  Plata- 
nist ;  a  ccecum  exists  also  in  the  Piked  Whale 
and  in  the  Whale-bone  Whale.  The  variations 
in  form  or  affinity  of  the  spleen  and  the  liver 
appear  to  have  no  essential  relation  with  the 
forms  of  the  stomach. 

[Mr.  Hunter  observes  that  "  there  is  a  con- 
siderable degree  of  uniformity  in  the  liver  in 
this  tribe  of  animals.  In  shape  it  nearly  re- 
sembles the  human,  but  is  not  so  thick  at  its 
base  nor  so  sharp  at  the  lower  edge,  and  is 
probably  not  so  firm  in  its  texture.  The  right 
lobe  (e,  Jig.  263)  is  the  largest  and  thickest, 
its  falciform  ligament  broad,  and  there  is  a 
large  fissure  (g)  between  the  two  lobes,  in  which 
the  round  ligament  passes.  The  liver  towards 
the  left  (f)  is  very  much  attached  to  the  sto- 
mach, the  little  epiploon  being  a  thick  sub- 
stance. There  is  no  gall-bladder."  "  The 
pancreas  is  a  very  long,  flat  body,  having-  its 
left  end  attached  to  the  right  side  of  the  first 
cavity  of  the  stomach :  it  passes  across  the 
spine  at  the  root  of  the  mesentery,  and  near  to 
the  pylorus  joins  the  hollow  curve  of  the 
duodenum,  along  which  it  is  continued,  and 
adheres  to  the  intestine,  its  duct  entering  that 
of  the  liver  near  the  termination  of  the  gut." — 
Phil.  Trans.  1787,  p.  410. 

The  structure  of  the  biliary  organs  has  a 
closer  resemblance  to  that  of  Quadrupeds 
in  the  Herbivorous  Cetacea,  and  differs  from 
that  above  described  in  the  presence  of  a  gall- 
bladder, besides  some  minor  points. 

In  the  Dugong  the  liver  is  a  transversely- 
oblong  viscus,  divided  into  three  lobes  with  a 
fourth  small  process  at  the  root  of  the  left  lobe, 
representing  the  lobulus  Spigelii.  It  is  as 
usual  convex  towards  the  diaphragm,  but  rather 
flattened  than  concave  towards  the  viscera,  the 
anterior  margin  thick  and  rounded.  Of  the 
three  larger  lobes  the  middle  one  is  the  smallest, 
of  a  square  shape,  projecting  forward,  and  as 
it  were  overhanging  the  gall-bladder,  which 
is  lodged  in  the  middle  of  the  inferior  surface. 
The  ligamentum  suspensorium  is  continued 
upon  the  middle  lobe,  immediately  above  the 
gall-bladder,  the  anterior  margin  of  this  lobe 
being  notched  to  receive  it,  and  the  remains  of 
the  umbilical  vein  entering  the  liver  an  inch 
above  the  fundus  of  the  gall-bladder.  The 
two  lateral  lobes  are  more  than  double  the  size 
of  the  cystic  lobe,  and  of  these  the  left  is  the 
largest.  Both  these  lobes  are  concave  to- 
wards the  small  middle  lobe,  which  they 
thus  surround  and  conceal.  The  lobulus 
Spigelii  is  of  a  flattened  and  square  shape, 
measuring  one  inch  and  a  quarter  in  length 


576 


CETACEA. 


and  one  inch  in  breadth.  The  gall-bladder 
is  of  an  elongated  form,  about  an  inch  in 
diameter  at  the  broadest  part.  It  does  not 
receive  the  bile  by  means  of  a  communication 
between  the  cystic  and  hepatic  ducts  as  in  most 
animals,  but  that  fluid  is  conveyed  directly 
into  it  by  two  distinct  hepato-cystic  canals  in 
the  same  manner  and  situation  as  the  ureters 
terminate  in  the  urinary  bladder.  The  two 
orifices  are  half  an  inch  apart  on  the  same 
transverse  line,  and  at  a  distance  of  three  inches 
from  diefundus  vesica  they  are  large,  readily 
admitting  a  full-sized  probe.  The  common 
ducts,  of  which  they  are  the  terminations,  are 
half  an  inch  in  length,  and  branch  off  into  the 
lobes  on  either  side.  The  inner  membrane  of 
the  gall-bladder  is  rugous;  it  has  a  longer 
investment  of  peritoneum  than  in  man.  Where 
it  ends  it  is  difficult  to  say,  as  it  gradually 
diminishes  in  size  after  the  entry  of  the  above 
ducts,  and  does  not  appear  to  be  separated 
from  the  cystic  duct  by  any  marked  contraction 
or  valvular  structure.  The  cystic  duct  is  about 
six  inches  in  length,  and  two  lines  in  diameter; 
dilates  a  little  before  entering  the  duodenum, 
and  as  it  passes  between  the  coats  of  that  intes- 
tine the  canal  is  provided  with  a  reticular 
valvular  structure  of  the  inner  membrane, 
which  may  probably  supply  the  deficiency  of 
this  structure  in  the  preceding  parts  of  the 
duct. 

Three  vena  cav<e  hepatica  from  the  three 
lobes  of  the  liver  join  the  vena  cava  inferior  at 
the  upper  and  posterior  edge  of  the  liver,  which 
is  not,  however,  perforated  by  it  as  in  most 
quadrupeds.  The  vena  porta,  formed  in  the 
usual  manner,  but  deriving  a  very  small  branch 
from  the  spleen,  enters  the  fissure  below  the 
gall-bladder. 

Sir  Everard  Home  takes  no  notice  of  the 
pancreas ;  Sir  Stamford  Raffles  merely  observes 
that  it  lay  <  below  the  duodenum.'  It  is 
situated  below  and  behind  the  pyloric  cavity 
of  the  stomach.  Its  length  in  a  Dugong  six 
feet  long  we  found  to  be  seven  inches ;  it  was 
obtuse  and  thick  at  the  splenic  or  left  end, 
where  its  diameter  was  two  inches,  and  gradu- 
ally growing  smaller  towards  the  duodenum, 
it  terminated  in  one  uncommonly  large  duct, 
which  was  three  lines  in  diameter  and  of  great 
length.  On  laying  open  this  canal  the  orifices 
of  from  twenty  to  thirty  tributary  ducts  were 
observable,  which  were  two  lines  in  diameter; 
the  coats  of  these  ducts  thick,  and  terminating 
in  flattened  lobules. 

The  spleen,  as  Sir  S.  Raffles  observes,  was 
very  small,  of  a  rounded  form ;  its  length  in 
the  larger  specimen  four  inches  and  a  half,  its 
breadth  in  the  middle  one  inch  and  a  half,  from 
which  it  tapered  to  either  end ;  its  structure 
finely  reticular. 

In  the  Piked  Whale  the  spleen  is  single  and 
of  small  proportional  size;  in  the  Porpesse 
this  organ  is  remarkable  for  its  subdivision  into 
distinct  portions,  of  which  one  is  generally 
about  the  size  of  a  walnut  (A,  fig.  263) ;  the 
others,  to  the  number  of  four,  five,  or  six  (/,  /), 
are  of  much  smaller  size.] 

The  Spouting   Whales   always    feed    upon 


living  food.  The  Dolphins  and  Cachalots  pur- 
sue or  catch  fish  principally,  and  large  Mollusks, 
whilst  Whales  prey  upon  the  numerous  little 
Molluscous  and  articulated  animals  and  Vermes 
which  swarm,  it  is  said,  in  the  northern  seas, 
and  in  the  number  of  which  are  reckoned 
crustaceans,  cuttle-fishes,  clios,  medusas,  sea- 
anemonies,  &c ;  but  in  this  respect  a  difference 
must  be  made  between  the  Balanopterye  and 
the  Whales,  properly  so  called  (Balterus),  for 
we  are  assured  that  the  first  also  feed  upon 
fish,  and  are  capable  of  swallowing  much 
larger  animals  than  the  latter. 

ORGANS  OF  CIRCULATION. — The  researches 
of  the  anatomist  on  the  circulating  system  of 
the  Cetaceans  have  not  hitherto  been  extended 
to  many  species.  In  its  essential  parts  it  is 
similar  to  that  in  other  Mammalia.  But  the 
peculiar  nature  of  Cetaceans,  and  the  great 
modifications  of  their  organs  of  movement, 
have  necessarily  produced  in  this  system,  not 
only  modifications  analogous  to  those  of  these 
organs,  but  vascular  developments  exclusively 
characteristic  of  these  animals. 

It  is  not  known  whether  the  Manatee  pre- 
sents anything  particular  in  regard  to  the  organs 
of  circulation,  but  the  heart  of  the  Dugong 
(Jig-  264)  and  of  the  Rytina  is  cloven  by  the 

Fig.  264. 


Heart  of  the  Dugong. 

deep  separation  of  the  two  ventricles,  .a  cir- 
cumstance which  adds  an  important  link  of 
affinity  to  those  already  subsisting  between 
these  animals. 

y'n  the  heart  of  the  Dugong,  the  ventricles, 
ir  Stamford  Raffles  has  correctly  described 
them,*  are  not  completely  detached  from  one 
another.  The  auricles  are  of  equal  size  and 
of  a  rounded  form.  In  the  right  auricle  (a), 
which  receives  a  single  superior  cava,  the 
coronary  vein,  and  the  inferior  cava,  there  is 
on  the  auricular  side  of  the  orifice  of  the 
latter  vein  a  fleshy  Eustachian  valve,  of  the 
size  and  form  which,  in  such  cases,  is  com- 
monly seen  in  the  human  subject.  The  valve 
of  the  foramen  ovale  has  a  reticulate  surface 
at  the  upper  margin,  but  is  entire  and  im- 
perforate.  The  right  ventricle  (b),  in  the  Du- 

*  Phil.  Trtns.  1820,  p.  174. 


CETACEA. 


577 


gong  previously  mentioned,  which  was  six  feet 
in  length,  was  three  inches  and  a  half  long 
and  three  inches  broad  at  the  base  ;  the  thick- 
ness of  its  parietes  one  line  and  a  half;  the 
carneae  columnae  are  few,  and  resemble  those 
in  man.  The  tricuspid  and  mitral  valves  are 
of  the  usual  form  and  structure,  but  the  latter 
are  broader  than  in  man,  measuring  each  one 
inch  three  lines  across  the  base.  The  diameter 
of  the  orifice  of  the  pulmonary  artery  (r)  is  one 
inch  and  a  half.  The  capacity  of  this  vessel 
is  very  great,  according  with  the  impediments 
to  the  transmission  of  blood  through  the  lungs 
which  must  arise  from  the  submarine  habits 
of  this  animal.  In  the  left  auricle  (d)  the  trans- 
verse pectinated  muscular  bands  are  equally 
if  not  more  developed  than  in  the  right.  The 
trace  of  the  foramen  ovale  is  more  evident  on 
this  side  the  septum  auriculare  than  in  the  right 
auricle ;  it  appeared  as  an  oblique  slit  directed 
upwards,  about  three  lines  broad,  but  was  com- 
pletely closed. 

The  parietes  of  the  left  ventricle  (e)  are 
half  an  inch  in  thickness;  there  is  nothing 
unusual  in  the  mitral  valve  or  the  carnea? 
columnae  connected  with  it ;  the  inner  surface 
of  the  ventricle  was  as  usual  smooth  below  the 
origin  of  the  aorta  (f).  The  breadth  of  the 
semilunar  valves  here  was  ten  lines,  the  dia- 
meter of  the  orifice  being  one-third  less  than 
that  of  the  pulmonary  artery.  The  ductus  ar- 
teriosus  was  completely  obliterated.] 

The  heart  in  the  Dolphins  and  Whales  does 
not  appear  to  have  undergone  any  remarkable 
modifications;  but  their  arterial  system  pre- 
sents a  very  important  one  in  the  infinite 
circumvolutions  of  arteries,  and  the  vast  ple- 
xuses of  vessels,  filled  with  oxygenated  blood, 
which  are  found  particularly  under  the  pleura 
and  between  the  ribs,  on  each  side  of  the  spine. 

[Of  this  remarkable  structure,  which  was 
discovered  by  Hunter,  we  here  subjoin  the 
original  description. 

"  The  general  structure  of  the  arteries  re- 
sembles that  of  other  animals ;  and  where  parts 
are  nearly  similar,  the  distribution  is  likewise 
similar.  The  aorta  forms  its  usual  curve, 
and  sends  off  the  carotid  and  subclavian  ar- 
teries. 

"  Animals  of  this  (the  Whale)  tribe,  as  has 
been  observed,  have  a  greater  proportion  of 
blood  than  any  other  known,  and  there  are 
many  arteries  apparently  intended  as  reservoirs, 
where  a  larger  quantity  of  arterial  blood  seemed 
to  be  required  in  a  part,  and  vascularity  could 
not  be  the  only  object.  Thus  we  find,  that  the 
intercostal  arteries  divide  into  a  vast  number 
of  branches,  which  run  in  a  serpentine  course 
between  the  pleura,  ribs,  and  their  muscles, 
making  a  thick  substance  somewhat  similar  to 
that  formed  by  the  spermatic  artery  in  the  Bull. 
Those  vessels,  every  where  lining  the  sides  of 
the  thorax,  pass  in  between  the  ribs  near  their 
articulation,  and  also  behind  the  ligamentous 
attachment  of  the  ribs,  and  anastomose  with 
each  other.  The  medulla  spinalis  is  surrounded 
with  a  net-work  of  arteries  in  the  same  man- 
ner, more  especially  where  it  comes  out  from 
the  brain,  where  a  thick  substance  is  formed 


by  their  ramifications  and  convolutions ;  and 
these  vessels  most  probably  anastomose  with 
those  of  the  thorax. 

"  The  subclavian  artery  in  the  Piked  Whale, 
before  it  passes  over  the  first  rib,  sends  down 
into  the  chest  arteries  which  assist  in  forming 
the  plexus  on  the  inside  of  the  ribs;  I  am  not 
certain  but  the  internal  mammary  arteries  con- 
tribute to  form  the  anterior  part  of  this  plexus. 
The  motion  of  the  blood  in  such  cases  must 
be  very  slow ;  the  use  of  which  we  do  not 
readily  see.  The  descending  aorta  sends  off 
the  intercostals,  which  are  very  large,  and 
gives  branches  to  this  plexus;  and  when  it 
has  reached  the  abdomen  it  sends  off,  as  in 
the  quadruped,  the  different  branches  to  the 
viscera  and  the  lumbar  arteries,  which  are 
likewise  very  large,  for  the  supply  of  that  vast 
mass  of  muscles  which  moves  the  tail. 

"  In  our  examination  of  particular  parts, 
the  size  of  which  is  generally  regulated  by 
that  of  the  whole  animal,  if  we  have  only 
been  accustomed  to  see  them  in  those  which 
are  small  or  middle-sized,  we  behold  them 
with  astonishment  in  animals  so  far  exceeding 
the  common  bulk  as  the  Whale.  Thus  the 
heart  and  aorta  of  the  Spermaceti  Whale  ap- 
peared prodigious,  being  too  large  to  be  con- 
tained in  a  wide  tub,  the  aorta  measuring  a 
foot  in  diameter.  When  we  consider  these  as 
applied  to  the  circulation,  and  figure  to  our- 
selves that  probably  ten  or  fifteen  gallons  of 
blood  are  thrown  out  at  one  stroke,  and  moved 
with  an  immense  velocity  through  a  tube  of  a 
foot  diameter,  the  whole  idea  fills  the  mind 
with  wonder."  *] 

It  is  to  be  presumed,  as  has  been  done,  that 
this  singular  complication  of  vessels  is  caused 
by  the  necessity  in  which  the  Cetaceans  are 
often  placed  of  suspending  their  respiration, 
and  consequently  the  oxygenation  of  their  blood, 
during  a  considerable  time.  These  numeerous 
arteries  form,  therefore,  a  reservoir  of  oxyge- 
nated blood,  which,  re-entering  the  circula- 
tion, supports  life  throughout,  where  venous 
blood  would  only  produce  death.  But  how 
this  blood  is  sent  to  this  general  system  of  arte- 
ries, or  what  is  the  peculiar  force  which  acts 
upon  it  to  this  effect,  is  a  point  on  which  we 
are  still  reduced  to  the  most  vague  conjectures. 

*  Phil.  Trans.  1787.  p.  415.  It  must  be  supposed 
that  M .  Breschet,  who  has  recently  written  on  the 
arterial  plexuses  of  the  Cetacea,  could  only  have 
known  the  preceding  description  by  extract  or  refe- 
rence, or  he  would  not  have  stated  that  the  structure 
in  question  had  been  'observee  par  J.  Hunter,  mai» 
indiquees  trop  sommaireraent  pour  pouvoir  etre  des 
lors  comptes  au  nombre  des  faits  acquis  a  la  sci- 
ence,' for  we  do  not  find  in  M.  Breschet's  paper 
any  essential  addition  to  the  original  account  given 
by  our  celebrated  anatomist,  either  with  respect  to 
the  observation  of  additional  facts,  to  their  clearer 
description,  or  to  the  physiological  inferences  de- 
duced from  them.  It  is  agreeable  to  find  that  M.  V. 
Baer,  whose  observations  on  the  subdivision  of 
the  brachial  arteries,  and  on  other  parts  of  the 
vascular  system  of  the  Porpesse,  are  real  additions 
to  the  anatomical  history  of  the  Cetacea,  by  no 
means  considers  it  necessary  to  depreciate  the 
value  of  the  observations  of  his  predecessors  iu 
the  same  field  of  enqniry. 


578 


CETACEA. 


The  disappearance  of  the  posterior  members 
has  occasioned  that  of  the  vessels  which  should 
nourish  those  members  ;  and  as  the  tail  has 
attained  a  considerable  development,  the  arte- 
ries and  veins  which  belong  to  this  last  part  of 
the  trunk  have  been  developed  in  the  same 
proportion.  The  abdominal  aorta  does  not 
send  off  any  external  iliacs,  but  is  continued 
underneath  the  tail  in  the  canal  of  the  inferior 
processes,  from  whence  its  ramifications  are  dis- 
tributed to  the  muscles  which  move  this  organ. 
The  modifications  of  the  venous  system  are  in 
many  respects  analogous  to  those  of  the  arteries. 

Fig.  266. 


The  quantity  of  blood  contained  in  the  vascu- 
lar system  appears  to  be  proportionally  much 
greater  than  in  the  other  Mammalia. 

[In  the  Porpesse  the  veins  are  almost  univer- 
sally devoid  of  valves,  so  that  they  can  be  as 
easily  injected  from  trunks  to  branches,  as  in 
the  reverse  direction.  The  plexiform  disposi- 
tion which  we  have  seen  to  characterize  so 
many  parts  of  the  arterial  system  is  still  more 
strongly  displayed  in  the  venous.  Thus  in  the 
system  of  the  anterior  vena  cava,  with  the  ex- 
ception of  the  trunk  of  that  vein  itself,  and  the 
short  jugular  veins  which  join  it,  an  internal 
and  an  external  jugular  branch,  and  a  pair  of 
large  subcutaneous  veins,  all  the  other  parts  of 
the  system  manifest  the  plexiform 
disposition.  This  is  most  remark- 
able in  the  large  venous  sinuses 
surrounding  the  central  axis  of  the 
nervous  system,  which  receives  the 
intercostal  veins,  and  by  means  of 
which  the  system  of  the  anterior 
cava  is  chiefly  brought  into  com- 
munication with  that  of  the  pos- 
terior cava ;  for,  as  V.  Baer  has 
observed,  there  is  no  intercommu- 
nicating channel  analogous  to  the 
vena  azygos  of  the  higher  Mam- 
malia. 

Of  the  venous  plexuses  belong- 
ing to  the  system  of  the  inferior 
cava,  that  which  is  found  at  the 
posterior  parietes  of  the  abdominal 
cavity  extending  from  below  the 
kidney  to  the  lower  boundary  of 
the  abdomen  is  the  most  remark- 
able, and  we  have  selected  in 
illustration  of  this,  the  figure  from 
Baer's  excellent  memoir  on  the  vas- 
cular system  of  the  Cetacea.*  In 
this  figure  (Jig.  266)  the  anterior 
parietes  of  the  abdomen  are  remo- 
ved. The  two  immense  lateral  de- 
pressor muscles  of  the  tail  are  seen 
at  A,  A,  and  B  shows  their  point 
of  convergence  to  be  inserted  into 
the  inferior  spinous  processes,  by 
which  the  cavity  of  the  abdomen  is 
contracted  and  defined  posteriorly. 
Just  anterior  to  this  commissure 
is  seen  the  termination  of  the  rec- 
tum H.  C,  C,  are  the  two  ischia. 
D,  D,  the  posterior  parietes  of  the 
chest  projecting  forwards  over  the 
abdomen.  On  the  right  side  the 
kidney  and  the  peritoneum  are  re- 
moved; on  the  left  side  they  are 
seen  in  situ,  and  also  a  part  of  the 
left  cornu  of  the  uterus  G,  with 
the  oviduct  and  ovary  K. 

At  p  is  seen  the  inferior  vena 
cava  cut  through,  which  lies  in  the 
interspace  of  the  two  great  depres- 
sors of  the  tail.  The  trunk  of  the 
vena  cava  seems  smaller  than  it 


Abdominal  venous  plexus  and  kidney  of  the  Porpesse. 


*  Ueber  das  Gefass  -  system  des 
Braunfisches,  Nova  Acta,  Phys.  Med. 
Leopold.  Carol,  torn.  xvii.  1835. 


CETACEA. 


579 


really  is,  on  account  of  its  deep  position  and 
the  overlapping  of  the  kidney,  E.  As  it  gets 
beyond  this  part  it  is  seen  to  dilate.  Two  veins, 
corresponding  to  the  veiiff  iliaca  of  Quadrupeds, 
(m,  mj  return  the  blood  in  part  to  the  tail,  and 
join  the  vena  cava  near  the  kidneys.  The  vein 
corresponding  to  the  caudal  or  sacro-median  of 
Quadrupeds  is  not  a  simple  vessel,  but  a 
plexus,  which  is  surrounded  and  protected  by 
the  inferior  spinous  processes ;  it  is  seen  aty'. 
A  venous  plexus  from  the  intestinal  canal  (g) 
terminates  in  the  right  iliac  vein,  which  is 
larger  than  the  left,  and  thus  establishes  a  com- 
munication between  it  and  the  portal  system. 
h  shows  a  muscular  vein,  and  i  the  termination 
of  a  hypogastric  plexus. 

The  more  important  plexuses  which  commu- 
nicate with  the  iliac  veins  are,  first,  the  perito- 
neal plexus  (/),  which  in  older  individuals,  and 
especially  at  the  season  of  sexual  excitement,  is 
much  more  considerable  than  is  here  repre- 
sented ;  and  secondly,  the  iliac  or  psoadic 
plexus  (k,  k),  which  forms  an  immense  reser- 
voir of  venous  blood.  It  is  situated  between 
the  under  surface  of  the  depressors  of  the  tail, 
which  represent  the  psoas  muscles,  and  the 
peritoneum,  reaching  from  behind  the  lower 
extremity  of  the  kidney  to  the  posterior  end  of 
the  abdomen,  and  forming  a  mass  of  closely 
interwoven  veins,  of  an  inch  or  more  in  thick- 
ness, and  serving  to  bring  the  subcutaneous 
veins  of  the  posterior  part  of  the  body  into 
communication  with  the  posterior  vena  cava. 

This  plexus  is  fed,  if  we  may  use  the  ex- 
pression, by  a,  an  inferior  vein;  b,  a  lateral; 
and  c,  a  superior  vein  of  the  tail,  which  unite 
to  form  an  ischiadic  sub-plexus,  d.  Laterally 
the  iliac  plexus  receives  from  five  to  seven 
veins,  which  return  the  blood  from  the  dorsal 
and  lateral  parietes  of  the  abdomen,  and  pierce 
the  lateral  abdominal  muscles  to  join  the  plexus 
at  ey  e.  On  its  internal  or  mesial  edge  the  iliac 
plexus  communicates  by  many  and  wide  aper- 
tures with  the  iliac  vein.  At  the  anterior  part 
of  the  abdomen  the  inferior  cava  receives  the 
plexus  phrenicus,  o,  u. 

The  condition  of  the  venous  system  above 
described,  while  it  is  admirably  adapted  to  the 
mode  and  sphere  of  existence  of  the  Cetaceans, 
presents  a  beautiful  instance  of  that  co-ordinate 
analogy  to  the  condition  of  the  veins  in  the 
embryo  of  the  higher  Mammals,  which  is  ex- 
hibited in  the  general  form  of  the  animals 
composing  this  the  lowest  order  of  the  class.] 

ORGANS  OF  RESPIRATION. — The  organs  and 
all  the  essential  phenomena  of  respiration  are 
the  same  in  the  Cetaceans  as  in  the  other 
Mammals.  They  have  been  made  the  subject 
of  but  few  observations. 

[In  the  Dugong  the  lungs  are  of  a  very  elon- 
gated and  flattened  form,  resembling  those 
which  Daubenton  has  figured  of  the  Manatee. 
They  are,  as  Sir  Everard  Home  has  observed, 
one-fourth  the  length  of  the  animal;  those 
from  the  animal,  eight  feet  long,  which  he  re- 
ceived from  Sir  Stamford  Raffles,  measuring 
two  feet.  They  are  convex  posteriorly  or  on 
the  dorsal  aspect,  flattened  on  the  opposite 
side,  and  along  this  surface  the  principal 


branches  of  the  bronchi  can  be  seen  through 
the  serous  covering.  The  upper  end  of  each 
lung  is  obtuse,  thick,  and  narrow ;  they  gradu- 
ally become  flatter  towards  the  lower  extremity, 
the  margin  of  which  is  rounded. 

The  whole  surface  of  these  lungs  presents  an 
appearance  somewhat  similar  to  that  of  the 
Turtle  (Chelonia  Mydas),  in  consequence  of 
the  large  size  of  the  superficial  air-cells,  which 
are  a  line  in  diameter  («,  «,  fig.  268.)  The 
great  extent  of  the  lungs  down  the  back,  and 
the  high  division  of  the  trachea,  and  consequent 
length  of  the  bronchi,  are  further  instances  of 
this  resemblance. 

Fig.  267. 


Cartilages  of  the  bronchus  of  the  Dugong. 

The  cartilages  of  the  bronchial  tubes  are 
continued  spirally  into  one  another  (fig.  267)  : 
the  pulmonary  artery  lies  to  the  outer  side  of 
the  bronchus  and  is  deeper  seated;  the  pulmo- 
nary vein  to  the  inner  side,  and  is  superficially 
situated.  The  principal  branch  of  the  bron- 
chus (b,  fig.  268)  runs  down  near  the  inner 
margin  of  the  lung,  and  continues  distinct  to 
within  four  inches  of  the  end ;  it  then  divides 
into  smaller  branches;  the  larger  ramifications 
are  given  off  from  its  outer  side,  c,  c.  In  all 
the  branches  the  cartilaginous  rings  continue 
distinct  and  strong  till  their  diameter  is  con- 
tracted to  one  or  two  lines ;  the  rings  passing 
irregularly  into  each  other  as  in  the  main 
trunks.  The  lining  membrane  of  the  air- 
tubes  is  thrown  into  longitudinal  rugae,  in- 
dicating their  dilatability.  We  have  before 
mentioned  the  large  size  of  the  pulmonary 
artery :  in  this  respect,  as  well  as  in  the 
structure  of  the  lung,  the  Dugong  manifests 
a  greater  similarity  to  the  reptile  than  the 
Porpoise  does.  In  this  animal  the  air-cells  in 
no  part  of  the  lung  exceed  a  sixth  part  of  the 
size  of  the  superficial  ones  in  the  Dugong ;  and 


580 


CETACEA. 

Fig.  268. 


Structure  of  the  lung  of  the  Dugong. 


the  pulmonary  artery  is  proportionally  smaller. 
From  the  difference  that  exists  in  the  locomo- 
tive habits  of  the  two  animals  arising  from  the 
difference  in  the  nature  of  the  food,  may  be 
deduced  the  circumstances  which  relate  to  the 
difference  in  the  respiratory  organ.  The  Por- 
poise, ever  bounding  and  gambolling  on  the 
surface,  breathes  as  it  were  at  will ;  whilst  the 
Dugong  is  compelled  to  prolonged  submersion 
in  order  to  acquire  its  food,  which  from  its 
fixed  attachment,  and  comparatively  innutri- 
tious  nature,  necessarily  demands  much  time 
in  collecting.] 

It  is  said  that,  in  the  Dolphins,  each  lung 
is  surrounded  by  muscular  fibres,  which  take 
part  also  in  the  acts  of  inspiration  and  expi- 
ration, and  that  the  lobes  communicate  with 
each  other  in  such  a  manner  that,  air  being 
introduced  through  one  of  the  bronchi  alone, 
they  are  all  filled  with  it. 

Fig. 


But  though  the  diaphragm,  the  lungs,  the 
bronchi,  and  the  trachea  are  only  found 
with  modifications  of  a  secondary  order,  the 
nostrils,  which  serve  intermediately  for  the 
passage  of  the  air,  between  the  atmosphere 
and  the  respiratory  organ,  present  very  im- 
portant ones.  It  is  especially  upon  these  mo- 
difications that  the  exterior  distinction  between 
the  Herbivorous  and  the  Spouting  Whales  de- 
pends. In  the  structure  of  the  nostrils,  the 
mechanism  by  which  the  phenomenon  of  the 
spouting  is  produced  has  necessarily  caused 
some  changes,  which,  on  the  one  hand,  appear 
to  have  necessitated  the  exclusion  of  the  organ 
of  smell,  and,  on  the  other,  to  have  led  to  the 
formation  of  a  new  organ  entirely  peculiar  to 
this  order  of  Mammalia. 

We  may  be  allowed  to  believe  that  this 
organ  is  essentially  the  same  in  the  Dolphins, 
the  Cachalots,  and  the  Whales ;  it  has  only, 

269. 


Vertical  section,  shewing  the  tongue,  larynx,  and  nostrils  of  the  Porpesse. 


CETACEA. 


581 


however,  been  studied  with  any  detail  in  the 
Dolphins,  and  its  principal  parts  consist  in 
the  larynx,  which  ascends  as  far  as  the  pos- 
terior nares ;  in  the  disposition  of  the  mus- 
cles of  the  pharynx,  which  have  the  power 
of  binding  the  anterior  part  of  the  respiratory 
organ ;  and  in  the  membranous  and  fleshy  bags 
placed  at  the  superior  part  of  the  nostrils. 

The  orifice  of  the  spouting  hole,  which  is 
simple  in  the  Dolphins,  is  situated  towards 
the  summit  of  the  head  (f,  Jig.  269);  in  the 
Cachalots  it  is  equally  simple,  and  situated 
at  the  superior  extremity  of  the  snout ;  and  in 
the  Whales  it  is  double,  and  opens  towards 
the  summit  of  the  head,  as  in  the  Dolphins, 
under  the  form  of  a  crescent,  the  convexity  of 
which  is  sometimes  forward  and  sometimes 
backward. 

In  the  Herbivorous  Cetaceans,  the  orifice  of 
the  nostrils  is  found,  in  the  Manatee  at  the 
anterior  extremity,  and  in  the  Dugong  at  the 
middle  and  upper  part  of  the  snout. 

[We  here  subjoin  the  detailed  description  of 
the  spouting  apparatus  of  the  Porpesse,  from 
the  pen  of  Baron  Cuvier.  "  If  we  trace  the 
oesophagus  upwards,  we  find  that  when  it 
arrives  opposite  the  pharynx  (a,  Jig.  269),  it 
appenrs  to  divide  into  two  passages,  of  which 
one  (6)  is  continued  onwards  to  the  mouth, 
while  the  other  (c)  mounts  to  the  nose: 
this  latter  passage  is  surrounded  with  mucous 
glands  and  fleshy  fibres  which  constitute 
several  muscles.  Some  of  these  are  longitu- 
dinal, arising  from  the  circumference  of  the 
posterior  orifice  of  the  bony  nostrils,  and  de- 
scending along  that  canal  to  the  pharynx  and 
its  lateral  parts;  the  others  are  annular  and 
seem  to  be  a  continuation  of  the  proper  mus- 
cle of  the  pharynx ;  as  the  larynx  rises  into 
this  passage  in  the  form  of  an  obelisk  or  py- 
ramid, these  annular  fibres  have  the  power  of 
grasping  it  by  their  contractions. 

"  All  this  part  is  provided  with  mucous  fol- 
licles which  pour  out  their  secretion  by  con- 
spicuous excretory  orifices.  The  lining  mem- 
brane of  the  nasal  passage  having  reached  the 
vomer  (</),  assumes  a  peculiar  texture;  it  be- 
comes thin,  smooth,  and  of  a  black  colour, 
is  apparently  destitute  of  vessels  and  nerves, 
and  is  very  dry. 

"  The  two  osseous  nasal  canals  are  closed  at 
the  superior  or  external  orifice  by  a  fleshy 
valve  in  the  form  of  two  semicircles,  attached 
to  the  anterior  margin  of  that  orifice/  which  it 
closes  by  means  of  a  very  strong  muscle  lodged 
above  the  intermaxillary  bones.  In  order  to 
open  it,  some  foreign  body  must  press  against  it 
from  below.  When  this  valve  is  closed,  it  cuts 
off  all  communication  between  the  nasal  pas- 
sages and  the  cavities  above  them.  These  ca- 
vities are  two  large  membranous  pouches  (e,  e\ 
formed  by  a  dark-coloured  mucous  skin,  much 
wrinkled  when  they  are  empty  ;  but  assuming, 
when  distended,  an  oval  figure,  which,  in  the 
Porpesse,  equals  the  capacity  of  a  wine-glass. 
These  two  pouches  are  lodged  beneath  the 
integument,  in  front  of  the  nostrils ;  they 
communicate  with  an  intermediate  space  im- 
mediately above  the  nostrils,  which  open  ex- 


ternally by  a  transverse  semilunar  slit.  Very 
strong  fleshy  fibres  form  an  expansion,  which 
covers  all  the  upper  surface  of  this  apparatus ; 
these  fibres  radiate  from  the  entire  circum- 
ference of  the  cranium  to  unite  above  the  two 
pouches,  and  are  adapted  to  compress  them 
forcibly.  Let  us  suppose  the  Cetacean  has 
taken  into  its  mouth  some  water  which  it 
wishes  to  eject :  it  moves  its  tongue  and  jaws  as 
if  it  were  about  to  swallow  it;  but,  closing  its 
pharynx,  it  forces  the  water  to  mount  into  the 
nasal  passages,  where  its  progress  is  accelerated 
by  annular  fibres,  until  it  raises  the  valve  and 
distends  the  membranous  pouches  above. 
Once  in  the  pouches,  the  water  can  be  re- 
tained there  until  the  animal  wishes  to  spout. 
For  that  purpose,  it  closes  the  valve  to  prevent 
the  descent  of  the  water  into  the  nasal  passages, 
and  it  forcibly  compresses  the  pouches  by 
means  of  the  muscular  expansions  which  cover 
them :  compelled  then  to  escape  by  the  nar- 
row crescentic  aperture,  it  is  projected  to  a 
height  corresponding  to  the  force  of  the  pres- 
sure." 

Urinary  organs. — The  Phytophagous  Ceta- 
ceans are  not  distinguished  by  a  form  and 
structure  of  the  kidney  different  from  that  in 
the  Zoophagous  tribes ;  for,  although  in  the 
Dugong  the  kidney  has  an  uniform  unbroken 
external  surface,  yet  in  the  genus  Rytina, 
according  to  Steller,  that  organ  is  subdivided 
into  a  great  number  of  lobules,  as  in  the  Seal 
and  Sea-Otter,  and  consequently  resembles  in 
this  respect  the  typical  or  true  Cetacea.  Hun- 
ter makes  the  same  statement  with  respect  to 
the  Manatee.* 

In  the  Dugong  the  tubuli  uriniferi  terminate 
by  two  lateral  series  of  eleven  mammillae  in  a 
single  elongated  pelvis,  from  which  the  ureter 
is  continued.  In  the  Porpesse  and  Whale 
there  is  no  common  pelvis,  but  the  ureter  com- 
mences by  more  than  two  hundred  branches 
from  as  many  distinct  lobes  or  renules,  of  the 
aggregate  of  which  the  entire  kidney  is  formed 
(E,Jig.  266).  Each  renule  is  of  a  conical  figure, 
having  its  base  towards  the  circumference,  and 
its  apex  towards  the  centre  of  the  kidney ; 
it  is  composed  of  a  cortical  and  medullary 
substance,  the  latter  terminating  in  a  single 
mammilla  at  the  apex,  where  it  is  surrounded 
by  a  long  infundibulum,  wide  at  its  com- 
mencement, where  it  embraces  the  base  of  the 
mammilla,  and  thence  becoming  smaller,  and 
uniting  with  others  to  form  the  common  ex- 
cretory duct. 

Miiller  found  that  each  of  the  lobules  of 
the  kidney  in  the  foetus  of  the  Dolphin  con- 
sisted principally  of  the  convoluted  uriniferous 
ducts  extending  from  the  apex  to  the  periphery 
of  the  lobule,  the  intertwinings  of  the  tubuli 
being  greatest  in  the  cortical  part  (Jig.  270). 

It  is  a  curious  fact  that  the  supra-renal  gland 
in  the  Porpesse  presents  a  certain  resemblance 
to  the  kidney  in  its  lobulated  exterior ;  but  the 
analogy  extends  no  farther,  for  on  making  a 
section  of  this  part,  it  is  seen  to  be  composed 
of  the  usual  continuous  compact  substance.] 

*  In  the  paper  on  Whales,  p.  412.^ 


582 


CETACEA. 


Fig.  270. 


A  section  of  one  of  the  lobes  or  renules  of  the  kidney 
of  a  Dolphin. 

The  Nervous  System. — The  nervous  system, 
like  the  greater  part  of  the  other  organic  sys- 
tems, has  in  many  species  of  the  Cetacea  been 
the  subject  only  of  superficial  observations. 
Formed  on  the  plan  of  that  of  Mammalia  in 
general,  it  has  followed  in  its  deve- 
lopment that  of  the  other  organs,  in 
all  cases  in  which  it  was  naturally  de- 
pendent on  such  modifications.  Thus 
the  lumbar  and  sacral  nerves  do  not 
give  origin  to  those  of  abdominal 
members,  whilst,  on  the  other  hand, 
the  coccygeal  nerves  are  found  nume- 
rous and  powerful.  The  olfactory 
nerves  do  not  exist,  unless,  as  some 
authors  say,  it  is  in  the  form  of  almost 
imperceptible  threads.  What  appears 
certain  is,  that  in  the  common  Dol- 
phin, and  in  the  common  Porpesse 
there  are  no  traces  of  ethmoidal 
openings ;  and  if  there  are  holes  in 
the  ethmoid  of  the  Whale,  they  are 
in  very  small  number,  and  nothing 
proves  that  they  give  passage  to 
nerves.*  In  the  common  Dolphin 
and  Porpesse,  the  brain  is  found  as 
richly  developed  as  in  any  Mammi- 
ferous  quadruped  whatever. 


To  judge  from  the  capaciousness  of  the 
skull,  the  other  species  of  this  family  of  Cetacea 
have  not  been  less  liberally  gifted  than  the 
common  Dolphin.  The  brain  of  the  Cachalots 
and  the  Whales  has  not  been  made  a  subject 
of  study,  or  has  been  so  only  in  a  very  super- 
ficial way.  To  judge  of  it  by  the  cranial 
cavity,  one  may  conclude  that  in  them  this 
organ  is  reduced  to  very  small  dimensions. 

[The  illustrations  of  the  brain  of  the  Cetacea 
(Jig.  271,  272,  273)  are  taken  from  the  ex- 
cellent figures  of  the  brain  of  the  Dolphin 
(  Delphinus  Delphi*),  published  byTiedemann 
in  the  second  volume  of  his  Zeitschrift  fur 
Physiologie,  (pi.  jai.  p.  251.)  The  following 
description  embodies  the  observations  of  the 
same  author  on  the  brain  of  the  Dolphin,  and 
of  Hunter  on  that  of  the  Baltenoptera  (Piked 
Whale).  In  a  young  specimen  of  the  Baltena 
rostrata,  which  measured  seventeen  feet,  Hunter 

Fig.  272. 


Fig.  271. 


Base  of  the  brain  of  a  Dolphin,  Delphinus  Delphis. 

found  that  the  brain  weighed  four 
pounds  eight  ounces.  In  a  young 
Baltena  mysticetus  nineteen  feet 
long,  Scoresby  found  the  weight  of 
the  brain  to  be  three  pounds  twelve 
ounces.  From  analogy  we  may 
suppose  that  the  brain  had  here 
acquired  nearly  its  full  development, 
which  gives  us,  taking  the  weight 
of  the  full  grown  whale  at  11,200 
pounds,  the  ratio  of  the  weight  of 
the  brain  to  that  of  the  body  as 
gg1^.  In  the  smaller  Cetacea, 
however,  the  brain  is  not  dimi- 
nished to  a  proportionate  size,  but 
exhibits  a  development  which  may 
be  said  to  be  extraordinary,  even 
in  the  Dolphin  of  six  feet  in 
length. 

In  tracing  the  brain  according  to 
Tiedemann's  method  from   below 


Brain  of  the  Dolphin,  Delphinus  Delphis. 

*  M.  F.  Cuvier  seems  here  to  have  overlooked  the 
fact  that  Hunter  had  established  the  existence  of 
an  organ  of  smell  in  the  Balaenidae.  He  observes, 


upwards,     we    first,   observe    the 

"  In  many  of  this  (the  Whale)  tribe,  there  is  no 
organ  of  smell  at  all ;  and  in  those  which  have 
such  an  organ,  it  is  not  that  of  a  Fish,  therefore 


CETACEA. 


583 


spinal  chord  (a,  fig.  272)  gently  expanding 
into  the  medulla  oblongata,  on  the  anterior 
surface  of  which  the  corpora  pi/rumiJalia  (6, 
Jig.  272)  are  seen  well  defined  and  prominent. 
At  the  point  where  they  begin  to  rise  above 
the  surface  of  the  medulla,  there  is  a  manifest 
decussation  of  their  internal  fibres;  they  pro- 
ceed through  the  pons  Varoli  (c),  and  are 
continued  into  the  crura  cerebri. 

The  corpora  olivaria  are  situated  near  the 
pyramidalia ;  they  do  not,  however,  project 
from  the  surface  as  in  the  human  brain,  but 
are  distinguishable  by  the  internal  grey  sub- 
stance (corpus  dentatum  oliv<e).  Their  medul- 
lary fibres  proceed  through  the  pons  and  enter 
the  bigeminal  bodies,  in  which  they  converge 
and  decussate  each  other. 

The  transverse  medullary  fibres,  which  are 
seen  in  most  Mammalia  extending  across  the 
under  surface  of  the  medulla  oblongata  imme- 
diately behind  the  pons,  and  which  Treviranus 
has  called  the  trapezium,  are  wanting  in  the 
brain  of  the  Dolphin,  as  in  that  of  the  Orang 
Utan  and  the  Human  subject 

The  two  posterior  columns  of  the  spinal 
chord  are  continued  (according  to  Tiedemann) 
as  the  corpora  restijbrmia  to  the  cerebellum. 
Between  these  is  situated  the  fourth  ventricle, 
from  the  floor  of  which  the  acoustic  nerves 
take  their  origin. 

The  very  large  size  of  the  cerebellum  in 
proportion  to  the  spinal  chord  and  cerebrum, 
which  Hunter  noticed  in  the  Piked  Whale,  is 
equally  remarkable  in  the  Dolphin.  The  cere- 
bellum is  deeply  divided  into  lobes,  of  which 
six  may  be  distinguished  on  the  upper  surface 
of  each  hemisphere.  Of  these,  two  small  lobes 
correspond  to  the  posterior  superior  lobes  of 
the  human  cerebellum. 

On  the  under  surface  we  remark 
the  posterior  inferior  lobes  (e\  the 
anterior  inferior  lobes  (fj,  one  lobe 
corresponding  to  the  amygdaloid 
lobe  of  Reil  (g),  and  the  Jloccus 
(/i).  Each  lobe  is  subdivided  by 
deep  fissures  into  smaller  lobes,  and 
these  again  by  shallow  anfractu- 
osities  into  lamelke.  The  middle 
or  vermiform  portion  of  the  cere- 
bellum (a,  Jig.  273)  is  not  sym- 
metrical, but  inclined,  like  the  cra- 
nium itself,  to  the  right  side.  The 
internal  medullary  substance  of  the 
cerebellum  resulting  from  the  di- 
vergent fibres  of  the  cms,  corpus 
restiforme,  and  processus  ad  testes, 
and  the  superadded  commissural 
fibres,  has  a  well-marked  internal 
grey  substance  or  corpus  fimbri- 

probably  not  calculated  to  smell  water.  It  becomes 
difficult  therefore  to  account  for  the  manner  in 
which  such  animals  smell  the  water  ;  and  why  the 
others  should  not  have  had  such  an  organ,  which 
seems  to  be  peculiar  to  the  large  and  small  Whale- 
bone Whales  (  Balaena  mysticetus  and  Baleenoptera 
rostrata);  the  organ,  in  those  which  have  it,  is  ex- 
tremely small,  when  compared  with  that  of  other 
animals,  as  well  as  the  nerve,  which  is  to  receive 
the  impression."— Phil.  Trans,  pp.  428,  430. 


atum,  and  is  covered  by  the  usual  external 
layer  of  similar  material.  Between  the  columns 
which  extend  from  the  cerebellum  to  the  bige- 
minal bodies,  the  medullary  lamella  called 
valvula  Vieussenii  is  situated.  The  pons  or 
commissure  of  the  cerebellum  (c,  fig.  272)  is  of 
large  size,  corresponding  to  the  hemispheres  of 
the  part  which  it  seems  to  associate  in  action. 

The  cerebrum  is  extended  backwards  over 
the  cerebellum,  but  the  posterior  parts  of  the 
hemispheres  diverge  from  one  another  so  as  to 
expose  a  part  of  the  cerebellum.  The  most 
striking  feature  of  the  cerebrum  is  its  great 
breadth,  which  exceeds  its  length,  a  disposition 
of  this  organ  peculiar  among  Mammalia  to 
the  Cetaceous  order.  Each  hemisphere  is  seen 
at  its  inferior  surface  to  be  divided  by  the 
fismra  magna  (/c,  Jig.  272)  into  an  anterior 
(/)  and  middle  lobe  (»i),  which  latter  is  con- 
tinued above  the  cerebellum  into  the  posterior 
lobe.  The  whole  external  surface  of  the  he- 
mispheres is  divided  by  deep  anfractuosities 
into  convolutions,  which  are  proportionally 
more  numerous  and  narrower  even  than  in  the 
human  brain.  This  structure  seems  common 
to  all  the  Cetacea ;  besides  the  observations  of 
Tiedemann  and  Cuvier  in  the  common  Dol- 
phin, the  numerous  convolutions  have  been 
remarked  by  Tyson  in  the  brain  of  the  Por- 
pesse,  and  by  Scoresby  in  that  of  the  Mysticete 
Whale. 

The  crura  cerebri  (t,  Jig.  272)  are  of  large  size; 
the  eminentiae  mammillares  (/?)  are  as  usual 
situated  between  them,  and  anterior  to  these 
are  the  infundibulum  and  pituitary  gland  (o). 

The  two  hemispheres  in  the  Dolphin's  brain 
described  by  Tiedemann,  measured  each  two 
inches  and  eleven  and  a  half  lines  in  length, 
and  were  united  by  a  corpus  callosum  (b,Jig. 

Fig.  273. 


273,)  of  one  inch  and  three  lines  in  length.  The 
chief  peculiarity  of  this  part  is  its  position, 
which  is  not  horizontal,  but  inclined  down- 
wards and  forwards.  The  bigeminal  bodies 
are  of  considerable  size  ;  the  anterior  ones  are 
rounded  and  lie  closer  together  than  the  pos- 
terior. These  have  an  oval  form,  and  are 
separated  by  a  depression  which  receives  the 


584 


CETACEA. 


anterior  part  of  the  vermiform  process  of  the 
cerebellum. 

The  pineal  gland  is  a  small  flattened  body 
about  two  lines  in  length,  connected  as  usual 
to  the  thalami  opt  id.  These  appear  in  each 
ventricle  in  the  form  of  an  oval  flattened 
body  (i,  fig.  273).  They  are  joined  together 
posteriorly  by  the  medullary  commissure. 
Tiedemann  did  not  observe  any  soft  commis- 
sure. 

The  third  ventricle  is  continued  anteriorly 
into  the  infundibulum. 

The  corpora  striata  (</)  are  proportionally  of 
small  size,  as  Hunter  observed  in  the  brain 
of  the  Whale.  They  are  united  anteriorly  by 
the  anterior  commissure. 

The  J'ornix  is  also  of  inconsiderable  size. 
The  slender  anterior  pillars  of  the  fornix  proceed 
to  the  mammillary  bodies,  and  send  forwards 
two  small  triangular  medullary  lamellae  to  the 
under  surface  of  the  anterior  part  of  the  corpus 
strialum,  from  which  the  septum  lucidum  is 
continued.  The  fornix  then  bends  backwards 
along  the  under  surface  of  the  corpus  callosum 
and  above  the  thalami,  and  its  hinder  crura 
sink  down,  diverging  from  each  other  to  form 
the  cornua  ammonis  (g).  These  bodies  are 
small,  thin,  but  broad,  and  exhibited  no  den- 
ticulated folds.  The  taenia  fimbriata  (A)  are 
attached  as  usual  to  the  external  border  of  the 
cornua. 

The  lateral  ventricles  are  capacious  though 
short;  they  extend,  as  in  the  human  brain, 
into  an  anterior,  a  middle,  and  a  posterior  horn  ; 
the  latter,  however,  is  very  small.  In  each 
ventricle  there  is  a  large  plexus  choroides,  which 
is  remarkable  for  the  transverse  parallel  folds 
of  membrane  which  support  the  divisions  of 
the  artery. 

With  respect  to  the  cerebral  nerves,  Tiede- 
mann states  that,  although  in  the  Dolphin  the 
brain  was  removed  with  every  precaution  from 
the  skull,  yet  he  could  not  perceive  the  slightest 
trace  of  the  olfactory  pair.  Hunter  and  Tyson 
equally  failed  to  detect  them  in  the  Porpesse. 
Treviranus,  however,  believed  that  with  the 
aid  of  a  magnifying  glass  he  had  detected  very 
delicate  filaments  in  the  situation  of  the  olfac- 
tory nerves  in  the  Porpesse.  But  supposing 
that  there  was  no  illusion  here,  which  could 
hardly  have  happened  to  so  accurate  and  close 
an  observer,  these  fibres  represent  only  a  very 
rudimental  condition  of  the  olfactory  nerves; 
and  we  may  observe  that  the  shortness  of  the 
anterior  lobes  of  the  brain,  and  the  smallness 
of  the  striated  bodies  are  closely  related  to  the 
absence  or  imperfect  development  of  the  first 
pair  of  nerves. 

With  respect  to  the  other  cerebral  nerves, 
they  are  relatively  larger  in  proportion  to  the 
brain  than  in  man.  The  optic  nerves  (2,  Jig. 
272)  rise  partly  from  the  thalami,  partly  from 
the  anterior  bigeminal  bodies  and  the  corpora 
geniculata;  they  curve  round  the  crura  cerebri, 
and  unite  as  usual  before  the  pituitary  gland. 
The  angle  at  which  the  nerves  diverge  from 
each  other  after  the  decussation  is  more  open 
than  in  other  Mammalia. 

The  accessory  nerves  of  the  eye  are  of  large 


size,  as  the  third  (3),  the  fourth  (4),  and  the 
sixth  (6)  pair. 

The  fifth  pair  (5),  which  emerge  from  the 
sides  of  the  pons,  but  arise  from  the  medulla 
oblongata  between  the  corpora  restiformia  and 
olivaria,  have  a  smaller  proportional  size  than 
in  man. 

The  nerves  concerned  in  the  actions  of 
respiration,  as  the  facial  (7),  the  pneumogastric 
(10),  and  the  recurrent  (11),  are  well  deve- 
loped, in  relation  to  the  large  size  of  the 
muscles  which  effect  the  respiratory  movements 
in  the  dense  medium  of  water. 

The  glosso-pharyngeal  nerve  (9)  and  the 
lingual  (12)  are  also  very  large,  corresponding 
to  the  vigorous  associated  actions  of  the  tongue 
and  pharynx,  which  must  take  place  during 
deglutition  in  the  Cetacea. 

But  perhaps  the  most  remarkable  nerve  for 
its  great  relative  size  is  the  acoustic  (8),  which 
certainly  testifies  to  the  delicate  sense  of  hear- 
ing in  the  Dolphins.] 

The  organs  of  the  senses,  with  the  exception 
of  that  of  smell,  are  composed,  in  all  the 
Cetaceans,  of  the  parts  which  essentially  con- 
stitute them  in  terrestrial  Mammalia,  and  are 
only  modified  with  reference  to  the  habitually 
aquatic  life  of  the  animals  of  this  order.  But 
little  inquiry  has  been  made  as  to  their  utility 
in  these  animals,  the  length  of  time  they  con- 
tinue serviceable,  and  the  characteristic  diffe- 
rences which  might  be  drawn  from  them  for 
the  distinction  of  the  species. 

Eye. — The  eye  of  the  Herbivorous  Cetaceans 
alone  is  provided  with  a  lateral  lid  or  membrana 
nictitans;  that  of  the  Spouting  Whales  is  de- 
void of  lachrymal  glands;  but  its  lids  are  fur- 
nished below  with  little  glands  which  secrete  a 
mucous  matter,  adapted  like  the  tears  for 
lubricating  the  sclerotica. 

[Hunter  observes  that  "  the  eye  in  this 
tribe  of  animals  is  constructed  upon  nearly 
the  same  principle  as  that  of  quadrupeds,  dif- 
fering, however,  in  some  circumstances ;  by 
which  it  is  probably  better  adapted  to  see  in 
the  medium  through  which  the  light  is  to  pass. 
It  is  upon  the  whole  small  for  the  size  of  the 
animal,  which  would  lead  to  the  supposition 
that  their  locomotion  is  not  great;  for,  I  believe, 
animals  that  swim  are  in  this  respect  similar  to 
those  that  fly ;  and  as  this  tribe  come  to  the 
surface  of  the  medium  in  which  they  live,  they 
may  be  considered  in  the  same  view  with  birds 
which  soar ;  and  we  find,  birds  that  fly  to 
great  heights,  and  move  through  a  considerable 
space,  in  search  of  food,  have  their  eyes  larger 
in  proportion  to  their  size. 

"  The  eyelids  have  but  little  motion,  and 
do  not  consist  of  loose  cellular  membrane,  as 
in  quadrupeds,  but  rather  of  the  common 
adipose  membrane  of  the  body  ;  the  connexion, 
however,  of  their  circumference  with  the  com- 
mon integuments  is  loose,  the  cellular  mem- 
brane being  less  loaded  with  oil,  which  allows 
of  a  slight  fold  being  made  upon  the  sur- 
rounding parts  in  opening  the  eyelids.  This 
is  not  to  an  equal  degree  in  them  all,  being 
less  so  in  the  Porpoise  than  in  the  Piked 
Whale. 


CETACEA. 


585 


Fig.  274. 


Section  of  tlie  eye  of  a  Whale. 

"  The  tunica  conjunctiva  (g,  g,  fig.  274), 
where  it  is  reflected  from  the  eyelid  to  the  eye- 
ball, is  perforated  all  round  by  small  orifices 
of  the  ducts  of  a  circle  of  glandular  bodies 
lying  behind  it. 

"  The  lachrymal  gland*  is  small,  its  use 
being  supplied  by  those  above-mentioned ;  and 
the  secretion  from  them  all,  I  believe  to  be 
a  mucus  similar  to  what  is  found  in  the  Turtle 
and  Crocodile.  There  are  neither  puncta  nor 
lachrymal  duct  (ductus  ad  nasum),  so  that  the 
secretion,  whatever  it  be,  is  washed  off  into 
the  water. 

"  The  muscles  which  open  the  eyelids  are 
very  strong;  they  take  their  origin  from  the 
head,  round  the  optic  nerve,  which  in  some 
requires  their  being  very  long,  and  are  so 
broad  as  almost  to  make  one  circular  muscle 
round  the  whole  of  the  interior  straight  mus- 
cles of  the  eye  itself.  They  may  be  divided 
into  four ;  a  superior,  an  inferior,  and  one  at 
each  angle ;  as  they  pass  outwards  to  the  eye- 
lids, they  diverge  and  become  broader,  and  are 
inserted  into  the  inside  of  the  eyelids  almost 
equally  all  round.  They  may  be  termed  the 
dilatores  of  the  eyelids ;  and,  before  they 
reach  their  inseition,  give  off  the  external 
straight  muscles,  which  are  small,  and  inserted 
into  the  sclerotic  coat  before  the  transverse  axis 
of  the  eye ;  these  may  be  named  the  elevator, 
depressor,  adductor,  and  abductor,  and  may 
be  dissected  away  from  the  others  as  distinct 
muscles.  Besides  these  four  going  from  the 
muscles  of  the  eyelid  to  the  eye  itself,  there  are 
two  which  are  larger,  and  enclose  the  optic 
nerve  with  the  plexus.  As  these  pass  outwards 
they  become  broad,  may  in  some  be  divided 
into  four,  and  are  inserted  into  the  sclerotic 
coat,  almost  all  round  the  eye,  rather  behind 
its  transverse  axis. 

"  The  two  oblique  muscles  are  very  long ; 
they  pass  through  the  muscles  of  the  eyelids, 
are  continued  on  to  the  globe  of  the  eye, 
between  the  two  sets  of  straight  muscles,  and 
at  their  insertions  are  very  broad :  a  circum- 

*  This    is    analogous    rather   to  the    Harderian 
gland,  being  situated  at  the  inner  or  nasal  side  of 
the  eyeball. 
VOL.  i. 


stance  which  gives  great  variation  to  the  motion 
of  the  eye. 

"  The  sclerotic  coat  (a,  a,  Jig.  274)  gives 
shape  to  the  eye,  both  externally  and  internally, 
as  in  other  animals;  but  the  external  shape  and 
that  of  the  internal  cavity  are  very  dissimilar, 
arising  from  the  great  difference  in  the  thick- 
ness of  this  coat  in  different  parts.  The  external 
figure  is  round,  except  that  it  is  a  little  flat- 
tened forwards ;  but  that  of  the  cavity  is  far 
otherwise,  being  made  up  of  sections  of 
various  circles,  being  a  little  lengthened  from 
the  inner  side  to  the  outer,  a  transverse  section 
making  a  short  ellipsis. 

"  In  the  Piked  Whale  ( Balanoptera  ros- 
trata)  the  long  axis  is  two  inches  and  three 
quarters,  the  short  axis  two  inches  and  one- 
eighth. 

"  The  posterior  part  of  the  cavity  is  a 
tolerably  regular  curve,  answering  to  the  dif- 
ference in  the  two  axises ;  but  forwards,  near 
the  cornea,  the  sclerotic  coat  turns  quickly  in, 
to  meet  the  cornea,  which  makes  this  part  of 
the  cavity  extremely  flat,  and  renders  the 
distance  between  the  anterior  part  of  the  scle- 
rotic coat  and  the  bottom  of  the  eye  not  above 
an  inch  and  a  quarter. 

"  In  the  Piked  Whale  the  sclerotic  coat,  at 
its  posterior  part,  is  very  thick  :  near  the  ex- 
treme of  the  short  axis  it  was  half  an  inch, 
and  at  the  long  axis  one-eight  of  an  inch  thick. 
In  the  Bottle-nose  Whale  ( Hyperoodon),  the 
extreme  of  the  short  axis  was  half  an  inch 
thick,  and  the  extremes  of  the  long  axis  about 
a  quarter  of  an  inch,  or  half  the  other. 

"  The  sclerotic  coat  becomes  thinner  as  it 
approaches  to  its  union  with  the  cornea,  where 
it  is  thin  and  soft.  It  is  extremely  firm  in  its 
texture  where  thick,  and  from  a  transverse  sec- 
tion would  seem  to  be  composed  of  tendinous 
fibres,  intermixed  with  something  like  carti- 
lage ;  in  this  section  four  passages  for  vessels 
remain  open.  This  firmness  of  texture  pre- 
cludes all  effect  of  the  straight  muscles  on  the 
globe  of  the  eye  by  altering  its  shape,  and 
adapting  its  focus  to  different  distances  of 
objects,  as  has  been  supposed  to  be  the  case  in 
the  human  eye. 

"  The  cornea  (6,  Jig.  274)  makes  rather  a 
longer  ellipsis  than  the  ball  of  the  eye ;  the  side 
of  which  are  not  equally  curved,   the     pp 
being  most  considerably  so.     It  is  a  segmen , 
of  a  circle  somewhat  smaller  than  that  of  the 
eyeball,  is  soft  and  very  flaccid.* 

"  The  tunica  choroides  resembles  that  of  the 
quadruped ;  and  its  inner  surface  is  of  a  silver 
hue,  without  any  nigrum  pigmentum.  The 
pigmentum  nigrum  only  covers  the  ciliary 
processes  (c,  c),  and  lines  the  inside  of  the  iris. 
The  retina  (e}  appears  to  be  nearly  similar  to 
that  of  the  quadruped. 

"  The  arteries  going  to  the  coats  of  the  eye 
form  a  plexus  passing  round  the  optic  nerve, 
resembling  in  its  appearance  that  of  the  sper- 
matic artery  in  the  Bull  and  some  other  ani- 
mals. 

*  Its  laminated  texture  is  well  displayed  in  the 
Whale;  Leeuwenhoek  counted  twemy-iwo  layers. 


.580 


CETACEA. 


"  The  crystalline  humour  (d)  resembles  that  of 
the  quadruped  ;  but  whether  it  is  very  convex 
or  flattened,  I  cannot  determine;  those  I  have 
examined  having  been  kept  too  long  to  pre- 
serve their  exact  shape  and  size.  The  vitreous 
humour  adheres  to  the  retina  at  the  entrance 
of  the  optic  nerve.  The  optic  nerve  (/)  is  very 
long  in  some  species,  owing  to  the  vast  width 
of  the  head."* 

The  crystalline  lens  is  of  a  spherical  form, 
but  slightly  flattened  anteriorly  :  it  is  inclosed 
in  a  strong  and  dense  capsule,  and  is  placed 
at  a  very  small  distance  from  the  cornea,  so 
that  it  diminishes  the  space  for  the  aqueous 
humour,  while  it  increases  that  for  the  vitreous; 
this  exists  in  a  greater  degree  than  is  shown  in 
the  subjoined  figure,  as  Soemmering,  from 
whose  work  '  De  oculorum  sectione  horizon- 
tali'  the  figure  is  taken,  himself  allows.  From 
the  peculiar  colour  and  eccentric  position  of 
the  nucleus  of  the  lens  in  the  Whale's  eye,  in 
which  it  is  of  a  dark  colour,  and  placed  in  the 
posterior  half  of  the  lens,  we  are  led  to  suspect 
that  the  section  of  the  lens  in  Soemmering's 
plate  is  imaginary.] 

Ear. — The  ear  is  without  any  external  con- 
cha; no  doubt  a  sphincter  has  the  office  of 
closing  the  entrance  of  the  auditory  canal,  to 
preserve  the  tympanum,  which  some  call  fi- 
brous, and  others  cartilaginous,  from  the 
contact  of  the  water.  The  Eustachian  tube 
exists  according  to  some  anatomists,  others 
deny  it.  The  senses  of  sight  and  hearing,  not- 
withstanding their  apparent  imperfection,  appear 
to  be  endued  with  great  delicacy.  Whale- 
catchers  assert  that  Whales,  Cachalots,  &c.  see 
and  hear  at  a  great  distance,  and  that,  in  order 
to  approach  them,  many  precautions  are  neces- 
sary ;  otherwise  these  animals  would  avoid 
them  by  a  sudden  retreat,  and  it  would  become 
necessary  to  recommence  the  long  and  labo- 
rious chase.  We  ought,  nevertheless,  to  add 
that  Scoresby,  who  speaks  of  the  delicacy 
of  hearing  of  the  Whales,  states  that  they 
remain  insensible  to  the  noise  of  the  report  of 
a  cannon. 

[For  the  most  accurate  and  philosophical 
description  of  the  Organ  of  Hearing  in  the 
present  tribe  we  again  recur  to  Hunter's  ad- 
mirable paper  on  the  organization  of  the 
Cetacea.  He  observes,  that  "  the  ear  is  con- 
structed much  upon  the  same  principle  as 
in  the  quadruped ;  but  as  it  differs  in  several 
respects,  which  it  is  necessary  to  particularize, 
to  convey  a  perfect  idea  of  it  the  whole  should 
be  described.  As  this  would  exceed  the  limits 
of  this  paper,  I  shall  content  myself  with  a 
general  description,  taking  notice  of  those  ma- 
terial points  in  which  it  differs  from  that  of  the 
quadruped. 

"  This  organ  consists  of  the  same  parts  as  in 
the  quadruped;  an  external  opening,  with  a 
membrana  tympani,  and  Eustachian  tube,  a 
tympanum  with  its  processes,  and  the  small 
bones. 

"  There  is  no  external  projection  forming  a 
funnel,  but  merely  an  external  opening.  We 

*  Philos.  Trans.  1787,  p.  440. 


can  easily  assign  a  reason  why  there  should  be 
no  projecting  ear,  as  it  would  interfere  with 
progressive  motion ;  but  the  reason  why  it  is 
not  formed  as  in  birds,  is  not  so  evident ;  whe- 
ther the  percussions  of  water  could  be  collected 
into  one  point  as  air,  I  cannot  say.  The  tym- 
panum is  constructed  with  irregularities,  so 
much  like  those  of  an  external  ear,  that  I  could 
suppose  it  to  have  a  similar  effect. 

"  The  external  opening  begins  by  a  small  hole, 
(a,  Jig.  275),  scarcely  perceptible,  situated  on 

Fig.  275. 


Organ  of  Hearing,  Porpesse. 


the  side  of  the  head  a  little  behind  the  eye.  It 
is  much  longer  than  in  other  animals,  in  con- 
sequence of  the  size  of  the  head  being  so  much 
increased  beyond  the  cavity  that  contains  the 
brain.  It  passes  in  a  serpentine  course  (6),  at 
first  horizontally,  then  down  wards,  and  afterwards 
horizontally  again,  to  the  membrana  tympani, 
where  it  terminates.  In  its  whole  length  it  is 
composed  of  different  cartilages,  which  are  irre- 
gular and  united  together  by  cellular  mem- 
brane, so  as  to  admit  of  motion,  and  probably 
of  lengthening  or  shortening,  as  the  animal  is 
more  or  less  fat. 

"  The  bony  part  of  the  organ  (c ,  c)  is  not  so 
much  inclosed  in  the  bones  of  the  skull  as  in  the 
quadruped,  consisting  commonly  of  a  distinct 
bone  or  bones,  closely  attached  to  the  skull, 
but  in  general  readily  to  be  separated  from  it; 
yet  in  some  it  sends  off,  from  the  posterior 
part,  processes  which  unite  with  the  skull.  It 
varies  in  its  shape,  and  is  composed  of  the  im- 


CETACEA. 


587 


mediate  organ   (or  labyrinth)    and    the   tym- 
panum. 

"  The  immediate  organ  is,  in  point  of  situa- 
tion to  that  of  the  tympanum,  superior  and  in- 
ternal, as  in  the  quadruped.  The  tympanum 
is  open  at  the  anterior  end,  where  the  Eusta- 
chian  tube  begins. 

"  The  Eustachian  tube  opens  on  the  outside 
of  the  upper  part  of  the  fauces  :  in  some  higher 
in  the  nose  than  others ;  highest,  I  believe,  in 
the  Porpoise.  From  the  cavity  of  the  tym- 
panum, where  it  is  rather  largest,  it  passes 
forwards  and  inwards,  and  near  its  termination 
appears  very  much  fasciculated,  as  if  glan- 
dular. (A  probe  passes  through  the  Eusta- 
chian tube  in  the  figure,  showing  its  nasal  ter- 
mination at  d.) 

"  The  Eustachian  tube  and  tympanum  com- 
municate with  several  sinuses,  which  passing 
in  various  directions  surround  the  bone  of  the 
ear.  Some  of  these  are  cellular,  similar  to  the 
cells  of  the  mastoid  process  in  the  human  sub- 
ject, although  not  bony.  There  is  a  portion  of 
this  cellular  structure  of  a  particular  kind,  being 
white,  ligamentous,  and  each  part  rather  round- 
ed than  having  flat  sides.* 

"  One  of  the  sinuses  passing  out  of  the  tympa- 
num close  to  the  membrana  tympani,  goes  a 
little  way  in  the  same  direction,  and  commu- 
nicates with  a  number  of  cells. 

"  The  whole  function  of  the  Eustachian 
tube  is  perhaps  not  known  ;  but  it  is  evidently 
a  duct  from  the  cavity  of  the  ear,  or  a  passage 
for  the  mucus  of  these  parts ;  the  external 
opening  having  a  particular  form  would  incline 
us  to  believe,  that  something  was  conveyed  to 
the  tympanum. 

"  The  bony  part  of  the  organ  is  very  hard 
and  brittle,  rendering  it  even  difficult  to  be  cut 
with  a  saw,  without  its  chipping  into  pieces. 
That  part  which  contains  the  immediate  organ 
is  by  much  the  hardest,  and  has  a  very  small 
portion  of  animal  substance  in  it;  for  when 
steeped  in  an  acid,  what  remains  is  very  soft, 
almost  like  a  jelly,  and  laminated.  The  bone 
is  not  only  harder  in  its  substance,  but  there  is 
on  the  whole  more  solid  bone  than  in  the  cor- 
responding parts  of  quadrupeds,  it  being  thick 
and  massy. 

u  The  part  containing  the  tympanum  is  a 
thin  bone,  coiled  upon  itself,  attached  by  one 
end  to  the  portion  which  contains  the  organ  ; 
and  this  attachment  in  some  is  by  close  contact 
only,  as  in  the  Narwhale ;  in  others,  the  bones  . 
run  into  one  another,  as  in  the  Bottle-nose  and 
Piked  Whales  ( Hyperoodon  and  Balanop- 
tera). 

"  The  concave  side  of  the  tympanum  is 
turned  towards  the  organ,  its  two  edges  being 
close  to  it ;  the  outer  is  irregular,  and  in  many 
only  in  contact,  as  in  the  Porpoise  :  while  in 
others  the  union  is  by  bony  continuity,  as  in 
the  Bottle-nose  Whale  (Hyperoodon),  leaving 
a  passage  on  which  the  membrana  tympani  is 

*  «'  These  communications  with  the  Eustachian 
tube  may  be  compared  to  a  large  bag  on  the  bases 
of  the  skull  of  the  Horse  and  Ass,  which  is  a  lateral 
swell  of  the  membranous  part  of  the  tube,  and  when 
distended  will  contain  nearly  a  quart." 


stretched,  and  another  opening,  which  is  the 
communication  with  the  sinuses. 

"  The  surface  of  the  bone  containing  the  im- 
mediate organ  (the  petrous  bone,  p,  Jig.  269) 
opposite  to  the  mouth  of  the  tympanum  is  very 
irregular,  having  a  number  of  eminences  and 
cavities." 

According  to  the  Baron  Cuvier*  the  petrous 
bone  in  the  Delphinida  is  permanently  lodged 
between  the  temporal  and  contiguous  parts  of 
the  occipital  bone;  it  forms  the  upper  and 
inner  part ;  the  tympanum  the  lower  and  outer. 
The  petrous  bone  is  brittle  and  very  thick.  It 
has  a  larger  portion,  an  irregular  ellipsoid, 
which  gives  attachment  to  the  tympanum  by 
its  outer  surface,  and  which  contains  the  three 
semicircular  canals ;  and  another  smaller  por- 
tion in  the  form  of  a  quarter  of  a  sphere,  which 
is  separated  from  the  first  by  a  pretty  deep  de- 
pression, and  is  occupied  internally  by  the 
cochlea.  The  acoustic  nerves  enter  by  fora- 
mina at  the  bottom  of  the  depression. 

The  tympanum  is  formed  by  a  thick  bony 
plate  folded  longitudinally,  so  as  to  form  a 
canal,  open  anteriorly,  whence  is  continued  the 
Eustachian  tube.  It  is  closed  behind,  where 
it  assumes  a  bilobate  figure,  and  adheres  above 
this  part  to  the  outer  and  posterior  part  of  the 
petrous  bone  by  a  rough  process,  which  is 
firmly  wedged  in,  but  does  not  anchylose  soon. 
It  adheres  to  it  also  by  a  part  of  the  external 
margin,  and  it  is  between  these  two  points  of 
adhesion  that  we  find  the  very  irregular  opening 
of  the  tympanum.  The  internal  margin  leaves 
a  long  interval  between  it  and  the  petrous  bone. 
Beneath  the  bilobate  portion  of  the  tympanum 
the  styloid  process  passes,  which  is  attached 
immediately  behind  it  by  ligaments  to  the  de- 
scending plate,  which  represents  the  mastoid 
process. 

The  bone  of  the  ear  of  the  Cachalot  displays 
great  relations  with  that  of  the  Dolphins, 
only  the  tympanum  is  shorter  and  less  lobated 
behind. 

The  bone  of  the  ear  in  the  Balanida  differs 
from  that  of  the  Delphinida:  by  the  enormous 
thickness  of  the  tympanum  (a,  fig.  276),  espe- 
cially at  the  inner  side.  This  tympanum  is  a 
little  more  closed  anteriorly,  but  leaves  between 
it  and  the  os  petrosum  (b)  on  the  inner  side  a 

Proportionally  shorter    and  wider    interspace, 
t  is  not  bilobed  posteriorly. 

The  petrous  bone  is  of  a  very  irregular  shape 
and  knotty  surface  ;  it  gives  off  two  large  rough 
processes,  of  which  one  is  situated  behind  and 
a  little  above,  and  articulates  with  a  corre- 
sponding process  of  the  tympanum,  is  wedged 
between  the  temporal  and  lateral  occipital 
bones;  and  the  other,  situated  anteriorly  and 
below,  is  articulated  by  a  squamous  suture 
with  the  part  of  the  temporal  which  descends 
to  furnish  the  articulation  of  the  lower  jaw. 
This  second  process,  which  in  the  BalteruB  is  as 
large  as  the  other,  is  very  small  in  the  Bala- 
noptera ;  nevertheless  the  ear-bone  of  the  Ba- 
Isenae  is  fixed  more  solidly  to  the  cranium  than 
that  of  the  Delphini. 

*  Oss.  Foss.  vol.  v.  pt.  i.  p.  300. 
2  Q  2 


388 


CETACEA. 


A  comparison  of  the  ear-bone  of  Balana 
Australis  with  that  of  Baltena  Mysticetus  cor- 
roborates  by  differences,  slight  indeed,  the  dis- 
tinction of  species  between  them. 

"  The  cavity  of  the  tympanum  (a,  a,  Jig. 
276)  is  lined  with  a  membrane,  which  also 
covers  the  small  bones  with  their  muscles,  and 
appears  to  have  a  thin  cuticle.  This  membrane 
renders  the  bones,  muscles,  tendons,  &c.  very 
obscure,  which  are  seen  distinctly  when  that  is 
removed.  It  appears  to  be  a  continuation  of 
the  periosteum,  and  the  only  uniting  substance 
between  the  small  bones.  Besides  the  general 
lining,  there  is  a  plexus  of  vessels,  which  is 
thin  and  rather  broad,  and  attached  by  one 
edge,  the  rest  being  loose  in  the  cavity  of  the 
tympanum,  somewhat  like  the  plexus  choroides 
in  the  ventricles  of  the  brain.  The  cavity,  we 
may  suppose,  intended  to  increase  sound,  pro- 
bably by  the  vibration  of  the  bone  ;  and  from 
its  particular  formation  we  can  easily  conceive 
that  the  vibrations  are  conducted,  or  reflected, 
towards  the  immediate  organ,  it  being  in  some 
degree  a  substitute  for  the  external  ear. 

"  The  external  opening  being  smaller  than  in 
any  animals  of  the  same  size,  the  membrana 
tympani  is  nearly  in  the  same  proportion.  In 
the  Bottle-nose  Whale,  the  Grampus,  and  Por- 
poise, it  is  smooth  and  concave  externally;  but 
of  a  particular  construction  on  the  inner  sur- 
face ;  for  a  tendinous  process  passes  from  it  to- 
wards the  malleus,  converging  as  it  proceeds 
from  the  membrane,  and  becoming  thinner  till 
its  insertion  into  that  bone.  I  could  not  dis- 
cover whether  it  had  any  muscular  fibres  which 
could  affect  the  action  of  the  malleus.  In  the 
Piked  Whale,  the  termination  of  the  external 
opening,  instead  of  being  smooth  and  concave, 
is  projecting,  and  returns  back  into  the  meatus 
for  above  an  inch  in  length,  is  firm  in  texture, 
with  thick  coats,  is  hollow  on  its  inside,  and 
its  mouth  communicating  with  the  tympanum ; 
one  side  being  fixed  to  the  malleus,  by  a  part 
similar  to  the  tendinous  process  which  goes 
from  the  inside  of  the  membrana  tympani  in 
the  others/'* 

In  the  figure  ^/zg.276),  which  represents  the 
internal  ear  in  the  Balaena  Mysticetus,  the  let- 
ters c,  d,  e  indicate  the  extent  of  the  membrana 
tympani,  the  letter  e  being  placed  on  the  part 
which  forms  a  convex  projection  into  the  tym- 
panic passage  :  /shows  the  triangular  ligamen- 
tous  process  which  attaches  the  handle  of  the 
malleus  (g)  to  the  membrana  tympani.  This 
connection  between  the  membrane  and  the 
ossicles  of  the  tympanum  is  denied  by  Sir 
Everard  Home,  who  wrote  a  paper  and  pub- 
lished two  plates  in  support  of  his  opinion.f 
After  quoting  Mr.  Hunter's  description  of  the 
attachments  of  the  membrana  tympani  in  the 
Piked  Whale,  Sir  Everard  observes,  "  the  fact 
is,  that  there  is  no  connexion  whatever  between 
the  membrana  tympani  and  the  malleus,  as 
will  be  explained ;  but  as  that  circumstance 
forms  the  great  peculiarity  in  the  organ  of  this 
species  of  Whale  (Baltena  mystketus,  L.) 

*  Hunter  in  Philos.  Trans.  1787,  p.  432. 
t  Philos.  Trans.  1812,  p.  88,  p!s.  I.  and  II. 


Fig.  276. 


Internal  ear  of  the  Mysticete  Whale. 

I  thought  it  right  to  quote  what  he  had  stated 
on  this  subject."  So  remarkable  an  anomaly 
as  an  absence  of  any  communication  between 
the  membrana  tympani  and  the  ossicula  audi- 
tus,  would  of  itself,  independently  of  our  inte- 
rest for  the  character  of  Hunter  as  an  accurate 
observer,  have  induced  us  to  spare  no  pains  to 
test  the  conflicting  statements  with  the  facts 
themselves ;  fortunately  in  this  instance  the 
preparations  figured  by  Sir  Everard  are  pre- 
served ;  we  have  carefully  examined  them,  and 
find  the  following  to  be  the  true  structure  of 
the  parts  in  question.  The  membrane  marked 
c  in  Sir  Everard  Home's  second  figure  is  con- 
tinuous at  d,  with  e  the  convex  projection  of 
the  membrana  tympani ;  whereas  the  edge  of 
the  shadow  is  so  strong  in  the  figure  as  to 
make  it  appear  as  if  c  and  e  were  separate 
membranes,  as  indeed  Sir  Everard  de- 
scribes them  to  be  :  they  are,  on  the  contrary, 
parts  of  the  same  membrana  tympani,  the  at- 
tachment of  which  is  extended  inwards  beyond 
the  circumference  of  the  termination  of  the 
bony  meatus  auditorius.  The  triangular  liga- 
ment/ which  is  common  to  all  the  Cetacea,  is 
attached  not  only  to  the  plane  portion  of  the 
ear-drum,  but  to  the  whole  of  one  side  of  the 
convex  portion  which  projects  into  the  meatus, 
and  is  affected  by  every  motion  of  that  part. 
It  is  a  thick  opaque  aponeurosis,  and  not,  as  it 
is  represented  in  the  plate,  a  semitransparent 
membrane  passing  clear  over  the  convex  part  of 
the  drum. 

"  A  little  way  within  the  membrana  tym- 
pani, are  placed  the  small  bones,  which  are 
three  in  number,  as  in  the  quadruped,  mal- 
leus (g),  incus  (h),  and  stapes  (i)  ;  but  in 
the  Bottle-nose  Whale  (Hyperoodon)  there  is  a 
fourth,  placed  on  the  tendon  of  the  stapedius 
muscle.  These  bones  are  as  it  were  suspended 
between  the  bone  of  the  tympanum,  and  that 
of  the  immediate  organ. 

"  The  malleus  has  two  attachments,  besides 
that  with  the  incus ;  one  close  to  the  bone  of 


CETAIKA. 


the  tympanum,  which,  in  the  Porpoise,  is 
only  by  contact,  but  in  others  by  a  bony 
union ;  the  other  attachment  is  formed  by  the 
tendon,  above  described,  being  united  to  the 
inner  surface  of  the  membrana  tympani.  Its 
base  articulates  with  the  incus. 

"  The  incus  is  attached  by  a  small  process  to 
the  tympanum,  and  is  suspended  between  the 
malleus  and  stapes.  The  process  by  which  it 
articulates  with  the  stapes  is  bent  towards  that 
bone. 

"  The  stapes  stands  on  the  vestibulum,  by  a 
broad  oval  base.  In  many  of  this  tribe,  the 
opening  from  side  to  side  of  the  stapes  is  so 
small  as  hardly  to  give  the  idea  of  a  stirrup. 

"  The  muscles  which  move  these  bones  are 
two  in  number,  and  tolerably  strong.  One 
arises  from  that  projecting  part  of  the  tym- 
panum which  goes  to  form  the  Eustachian 
tube,  and  running  backwards  is  inserted  into  a 
small  depression  on  the  anterior  part  of  the 
malleus.  The  use  of  this  muscle  seems  to  be 
to  tighten  the  membrana  tympani ;  but  in  those 
which  have  the  malleus  anchylosed  with  the 
tympanum,  we  can  hardly  conjecture  its  use. 
The  other  (o)  has  its  origin  from  the  inner  surface 
of  the  tympanum,  and  passing  backwards  is 
inserted  into  the  stapes  by  a  tendon,  in  which 
I  found  a  bone  in  the  large  Bottle-nose.  This 
muscle  gives  the  stapes  a  lateral  motion.  What 
particular  use  in  hearing  may  be  produced  by 
the  action  of  these  muscles  I  will  not  pretend 
to  say  ;  but  we  must  suppose  whatever  motion 
is  given  to  the  bones  must  terminate  in  the 
movement  of  the  stapes. 

"  The  immediate  organ  of  hearing  is  contained 
in  a  round  bony  process,  and  consists  of  the 
cochlea  and  semicircular  canals,  which  some- 
what resemble  the  quadruped ;  but  besides  the 
two  spiral  turns  of  the  cochlea,  there  is  a  third, 
which  makes  a  ridge  within  that  continued 
from  the  foramen  rotundum  and  follows  the 
turns  of  the  canal. 

"  The  cochlea  (A,  Jig.  276)  is  much  larger 
when  compared  with  the  semicircular  canals, 
than  in  the  human  species  and  quadruped." 

Besides  its  greater  relative  size,  the  coch- 
lea of  the  Delphinultf  differs  from  that  of 
the  human  subject  in  the  greater  pro- 
portional extent,  and  especially  the  form  and 
disposition  of  the  scala  vestibuli,  which,  in- 
stead of  being  one  compartment  of  a  single 
lube  divided  in  the  direction  of  its  axis,  is  a 
complete  conical  tube.  It  also  forms  an  oblique 
sigmoid  curve  before  commencing  its  spiral 
turns,  which  are  two  and  a  half  in  number. 

The  semicircular  canals  have  the  same  dis- 
position as  in  Mammalia,  but  are  relatively 
smaller. 

Cuvier,  in  correcting  the  error  into  which 
Camper  had  fallen  when  he  denied  the 
existence  of  the  semicircular  canals  in  the 
Whale,  appears  to  have  overlooked  the  fact 
that  they  had  previously  been  discovered  in 
the  Cetacea  by  Hunter.  And  it  is  simply  be- 
cause they  do  not  possess  any  difference  of 
note  as  compared  with  other  Mammalia,  (ex- 
cept in  their  relative  volume  to  other  parts  of 
the  labyrinth  which  Hunter  is  careful  to  point 


out,)  that  they  are  not  described  by  him  with 
the  same  minuteness  and  detail  as  the  cochlea 
and  other  parts  of  the  organ.  It  may  also  be 
observed  that  the  more  extensive  researches  of 
Hunter  preserved  him  from  the  error  into  which 
Cuvier  has  fallen  of  ascribing  to  the  Cetacea  a 
structure  of  the  cochlea  which  is  peculiar  to  a 
small  part  only  of  the  order.  The  depression 
of  the  gyrations  of  the  cochlea  to  nearly  the 
same  plane,  and  their  limitation  to  one  and  a 
half  in  number,  is  certainly  not  applicable  to 
the  Delphinidte,  and  it  may  be  doubted  how 
far  it  can  be  with  accuracy  asserted  of  the 
Balance.* 

The  canals  which  establish  a  communication 
between  the  labyrinth  and  the  interior  of  the 
cranium,  viz.  the  aqueductus  vestibuli  and 
aqueductus  cochleae,  are  very  large  in  the  Del- 
phinidce,  especially  the  latter.] 

Taste. — This  sense  probably  exists  in  the 
Herbivorous  Cetaceans,  whose  tongue,  although 
but  slightly  moveable,  has  notwithstanding  a 
complicated  and  delicate  structure.  But  has 
this  sense  a  special  organ  in  the  Spouting  Ce- 
taceans? Some  doubts  may  be  allowed  to 
exist  on  this  subject.  The  tongue  of  the  Dol- 
phin and  that  of  the  Porpoise  have  neither 
fossulate  papillae  nor  conical  papillae  ;  they  only 
present  on  their  surface  slight  elevations,  of 
which  the  middle  appears  to  be  perforated,  and 
their  edges  are  fringed,  as  if  for  multiplying 
the  sensations  of  touch. 

Touch. — The  general  organ  of  touch,  the 
skin,  has  formed,  in  the  Spouting  Cetaceans, 
the  subject  of  important  researches,  which  have 
given  a  more  extended  knowledge  of  this  organ 
in  general  than  was  before  possessed. 

According  to  the  observations  of  MM. 
Breschet  and  Roussel  de  Vauzeme,  there  may 
be  distinguished  in  the  skin  of  the  Cetaceans, 
as  in  that  of  other  Mammals,  six  principal 
constituents  which  either  penetrate  or  are 
superimposed  on  one  another,  but  which  are 
severally  destined  to  fulfil  a  special  function. 

1.  The  derm  or  corium  (le  derme),  a  dense 
fibrous  cellular  texture,  which  contains  and 
protects  all  the  other  parts-of  the  skin.     In 
the  Whale  it  is  constantly  white  and  opake, 
and  its  peripheral  surface  presents  a  series  of 
papillae,  the  intervals  of  which  are  occupied 
by   the  epidermis,  which    forms    for    each  a 
sheath. 

2.  The  papillary  bodies    (les  corps  papil- 
laires)  consist  of  papillae  covered  by  the  derm. 
They  have  a  nacrous  lustre,  and  are  several 
lines  in  length   in  the  Whale,   but  are  much 
shorter  in  the  common  Dolphin  and  Porpesse. 
These  papillae  are  composed  of  fibres  pene- 
trated by  vessels ;  they  originate  from  the  sub- 
cutaneous nervous  plexus'and  return  back  again 

.to  the  same  ;  the  derm  serves  merely  as  a 
sheath  to  the  papillae,  the  extremities  of  which 
exercise  the  sense  of  touch. 

3.  The  sudorific  apparatus  (Vappareil  sudo- 
rifique)  consists  of  soft,  elastic,  spiral  canals, 
w'hich  extend  through  the  entire  thickness  of 

*  See  Ossem.  Foss.  vol.  v.  pt.  i.  p.  300,  and 
Le9ons  d'Anat.  Comparee,  vol.  ii.  p.  4t>7. 


CETACEA. 


the  derm,  and  open  in  the  intervals  of  the 
papillae  by  an  orifice  generally  closed  by  a 
small  epidermic  valve. 

4.  The  inhalent  apparatus  (Vappareil  (Tin- 
lialution)    is    formed    by    extremely   delicate 
canals,    which   are  smooth,    straight,    silvery, 
branched,     and    very   easily  ruptured  :    they 
originate   in  a  plexus  extended  in  the  dermis 
beneath  the  sudorific  canals,   anastomose  to- 
gether, and  are  provided  with  partitions.     The 
lymphatic   vessels   have    no   connection   with 
these  canals,  which  communicate  directly  with 
the  arteries  and  veins.     They   are   absorbing 
canals. 

5.  The  mucous  apparatus  (Vappareil  blen> 
nogene).      This    is    composed    of    secerning 
glands  and   excretory  ducts,  which  open  be- 
tween the  papillae  like  the  orifices  of  the  pre- 
ceding canals.     It  is  wholly  contained   in  the 
derm,  and  produces  a  mucous  material,  which 
by  desiccation   (en  se  dessechant)  becomes  the 
cuticle.     In  the  Whales  this  cuticle  acquires 
an  extreme  thickness :    it  is  much  thinner  in 
the  Dolphins. 

6.  The  colorific  apparatus  (Vappareil  chro- 
matogene)  is  likewise  composed  of  secerning 
glands  and  excretory  ducts ;  it  is  situated  in 
the   first  superior  (peripheral)  layers  of   the 
corium  on  the  right  and  left  sides  of  the  outlet 
of  the  excretory  ducts  of  the  preceding  appa- 
ratus, and   it  pours  out  the  coloured  product 
at  the  same  point  where  the  mucous  matter  is 
excreted,  where  it  stains  it. 

[It  may  be  questioned  how  far  this  expla- 
nation satisfactorily  accounts  for  the  formation  of 
cuticle  in  animals  living  habitually  under  water. 
The  whole  account  is  to  be  received  with  reserve, 
and  requires  to  be  confirmed  by  further  ob- 
servations, especially  as  regards  the  reflexion 
of  the  nervous  fibrils  and  the  sudorific  and 
inhalent  apparatuses.] 

We  do  not  stop  to  examine  how  far  this 
analysis  serves  to  explain  the  different  phe- 
nomena which  the  external  teguments  of  the 
Mammalia  present.  But  admitting  it  as  it  is 
presented  to  us,  it  results  that  the  sensations 
of  touch  must  be  lively  and  delicate  in  the 
Cetacea :  the  great  development  of  their  pa- 
pillary apparatus  leads  to  this  conclusion. 
Nevertheless,  the  most  generally  received  opi- 
nion is  that  the  common  Dolphin,  notwith- 
standing the  delicacy  of  its  epidermis,  has  but 
little  tactile  sensibility.  But  is  this  opinion 
devoid  of  foundation?  or  is  it  explicable  on 
the  ground  of  the  deposition  of  fat,  which 
penetrates  every  part  of  the  skin,  and  is  accu- 
mulated in  a  dense  layer  beneath  it,  so  as  to 
enfeeble  the  sensibility  of  the  surface,  accord- 
ing to  the  common  belief.  This  is  the  opinion 
to  which  we  have  arrived.  With  respect  to 
the  Balaenidae  no  difficulty  exists  on  account 
of  the  thickness  and  horny  texture  of  the  epi- 
dermis. 

[According  to  Hunter's  views  the  reticular 
network  containing  the  blubber,  which  he  de- 
scribes as  fine  in  the  Porpoise,  Spermaceti, 
and  large  Whale-bone  Whale  ( Balana),  and 
coarse  in  the  Grampus  and  small  Whale-bone 
Whale  (BalanopteraJ,  forms  part  of  the  skin ; 


for  he  observes  that  "  the  cutis  seems  to  be 
the  termination  of  the  cellular  membrane  of 
the  body  more  closely  united,  having  smaller 
interstices  and  becoming  more  compact,"  and 
that  the  distinction  between  the  skin  and  cel- 
lular membrane  is  much  less  obvious  in  fat 
than  in  lean  animals;  "  for  the  cells  of  both 
membrane  and  skin  being  loaded  with  fat,  the 
whole  has  more  the  appearance  of  one  uniform 
substance.  This  uniformity  of  the  adipose 
membrane  and  skin  is  most  observable  in  the 
Whale,  Seal,  Hog,  and  the  Human  Species."*] 

In  the  Balanopterte  the  integument  covering 
the  ventral  surface  of  the  neck,  thorax,  and 
anterior  part  of  the  abdomen,  is  disposed  in 
longitudinal  folds,  about  five-eighths  of  an 
inch  in  breadth  in  the  contracted  state.  The 
skin  is  very  soft  in  the  insterstices  of  the  folds, 
and  covered  there  with  a  thinner  cuticle :  it 
possesses  great  elasticity  over  the  whole  of  the 
plicated  surface.  A  panniculus  carnosus  ad- 
heres closely  to  this  part  of  the  skin,  but  is 
separated  by  a  loose  cellular  membrane  from 
the  deep-seated  muscles ;  in  which  space  the. 
blubber  is  in  smaller  quantity  than  on  the  dorsal 
and  lateral  parts  of  the  body. 

Besides  the  adipose  substance  which  is  ac- 
cumulated beneath  the  integument,  another 
secretion  of  a  peculiar  kind,  called  Sperma- 
ceti, which  is  analogous  in  many  of  its  pro- 
perties to  the  adeps,  is  met  with  in  certain 
species  of  Cetacea,  but  more  particularly  in 
the  genera  Catodon  and  Physeter,  which  are 
hence  termed  Spermaceti  Whales.  Of  this 
substance  Mr.  Hunter  gives  the  following 
account  from  a  dissection  of  a  recent  specimen 
of  one  of  these  Whales. 

[  "  What  is  called  spermaceti  is  found  every 
where  in  the  body  in  small  quantity,  mixed 
with  the  common  fat  of  the  animal,  bearing  a 
very  small  proportion  to  the  other  fat.  In  the 
head  it  is  the  reverse,  for  there  the  quantity  of 
spermaceti  is  large  when  compared  to  that  of 
the  oil,  although  they  are  mixed,  as  in  the 
other  parts  of  the  body. 

"  As  the  spermaceti  is  found  in  the  largest 
quantity  in  the  head,  and  in  what  would  ap- 
pear on  a  slight  view  to  be  the  cavity  of  the 
skull,  from  a  peculiarity  in  the  shape  of  that 
bone,  it  has  been  imagined  by  some  to  be  the 
brain. 

"  These  two  kinds  of  fat  in  the  head  are  con- 
tained in  cells,  or  cellular  membrane,  in  the 
same  manner  as  the  fat  in  other  animals ;  but 
besides  the  common  cells  there  are  larger  ones, 
or  ligamentous  partitions  going  across,  the 
better  to  support  the  vast  load  of  oil,  of 
which  the  bulk  of  the  head  is  principally 
made  up. 

"  There  are  two  places  in  the  head  where 
this  oil  lies ;  these  are  situated  along  its  upper 
and  lower  part :  between  them  pass  the  nos- 
trils, and  a  vast  number  of  tendons  going  to 
the  nose  and  different  parts  of  the  head. 

"  The  purest  spermaceti  is  contained  in  the 
smallest  and  least  ligamentous  cells:  it  lies 
above  the  nostril,  all  along  the  upper  part  of 

*  Ibid.  p.  395. 


CKTACEA. 


the  head,  immediately  under  the  skin,  and 
common  adipose  membrane.  These  cells  re- 
semble those  which  contain  the  common  fat  in 
the  other  parts  of  the  body  nearest  the  skin. 
That  which  lies  above  the  roof  of  the  mouth, 
or  between  it  and  the  nostril,  is  more  inter- 
mixed with  a  ligamentous  cellular  membrane, 
and  lies  in  chambers  whose  partitions  are  per- 
pendicular. These  chambers  are  smaller  the 
nearer  to  the  nose,  becoming  larger  and  larger 
towards  the  back  part  of  the  head,  where  the 
spermaceti  is  more  pure. 

"  This  spermaceti,  when  extracted  cold,  has 
a  good  deal  the  appearance  of  the  internal 
structure  of  a  water  melon,  and  is  found  in 
rather  solid  lumps. 

"  About  the  nose,  or  anterior  part  of  the 
nostril,  I  discovered  a  great  many  vessels, 
having  the  appearance  of  a  plexus  of  veins, 
some  as  large  as  a  finger.  On  examining  them, 
I  found  they  were  loaded  with  the  spermaceti 
and  oil ;  and  that  some  had  corresponding 
arteries.  They  were  most  probably  lym- 
phatics ;  therefore  I  should  suppose,  that  their 
contents  had  been  absorbed  from  the  cells  of 
the  head.  We  may  the  more  readily  suppose 
this,  from  finding  many  of  the  cells,  or  cham- 
bers, almost  empty;  and  as  we  may  reason- 
ably believe  that  this  animal  had  been  some 
time  out  of  the  seas  in  which  it  could  procure 
proper  food,  it  had  perhaps  lived  on  the  super- 
abundance of  oil. 

"  The  solid  masses  are  what  are  brought 
home  in  casks  for  spermaceti. 

"  I  found,  by  boiling  this  substance,  that 
I  could  easily  extract  the  spermaceti  and  oil 
which  floated  on  the  top  from  the  cellular 
membrane.  When  I  skimmed  off  the  oily 
part,  and  let  it  stand  to  cool,  I  found  that  the 
spermaceti  crystallised,  and  the  whole  became 
solid;  and  by  laying  this  cake  upon  any 
spongy  substance,  as  chalk,  or  on  a  hollow 
body,  the  oil  drained  all  off,  leaving  the  sper- 
maceti pure  and  white.  These  crystals  were 
only  attached  to  each  other  by  edges,  forming 
a  spongy  mass ;  and  by  melting  this  pure 
spermaceti,  and  allowing  it  to  crystallise,  it 
was  reduced  in  appearance  to  half  its  bulk, 
the  crystals  being  smaller  and  more  blended, 
consequently  less  distinct. 

"  The  spermaceti  mixes  readily  with  other 
oils,  while  it  is  in  a  fluid  state,  but  separates 
or  crystallises  whenever  it  is  cooled  to  a  certain 
degree ;  like  two  different  salts  being  dissolved 
in  water,  one  of  which  will  crystallise  with  a 
less  degree  of  evaporation  than  the  other ;  or, 
if  the  water  is  warm,  and  fully  saturated,  one 
of  the  salts  will  crystallise  sooner  than  the 
other,  while  the  solution  is  cooling.  I  wanted 
to  see  whether  spermaceti  mixed  equally  well 
with  the  expressed  oils  of  vegetables  when 
warm,  and  likewise  separated  and  crystallised 
when  cold,  and  on  trial  there  seemed  to  be 
no  difference.  When  very  much  diluted  with 
the  oil,  it  is  dissolved  or  melted  by  a  much 
smaller  degree  of  heat  than  when  alone  ;  and 
this  is  the  reason,  perhaps,  that  it  is  in  a  fluid 
state  in  the  living  body. 

"  If  the  quantity  of  spermaceti  is  small  in 


proportion  to  the  other  oil,  it  is,  perhaps,  nearly 
in  that  proportion  longer  in  crystallising ;  and 
when  it  does  crystallise,  the  crystals  are  much 
smaller  than  those  that  are  formed  where  the 
proportion  of  spermaceti  is  greater.  From  the 
slowness  with  which  the  spermaceti  crystallises 
when  much  diluted  with  its  oil,  from  a  con- 
siderable quantity  being  to  be  obtained  in  that 
way,  and  from  its  continuing  for  years  to  crys- 
tallise, one  would  be  induced  to  think,  that 
perhaps  the  oil  itself  is  converted  into  sper- 
maceti. 

"  It  is  most  likely,  that  if  we  could  dis- 
cover the  exact  form  of  the  different  crystals 
of  oils,  we  should  thence  be  able  to  ascertain 
both  the  different  sorts  of  vegetable  oils,  much 
better  than  by  any  other  means ;  in  the  same 
manner  as  we  know  salts  by  the  forms  into 
which  they  shoot."*] 

ORGANS  OF  GENERATION. — The  organs  con- 
cerned in  the  reproduction  of  the  species  do 
not  exhibit  the  same  type  of  conformation  in 
the  Phytophagous  as  in  the  Zoophagous  species. 
In  the  former  the  mammse  are  pectoral,  in  the 
latter  inguinal  or  rather  pudendal,  since  they 
are  situated  on  each  side  of  the  vulva  :  in  both 
orders  their  number  never  exceeds  two.  The 
vulva,  which  resembles  in  its  form  that  of  the 
Ruminants,  presents  nothing  peculiar  in  its 
structure. 

The  penis  is  attached  to  the  rudimental 
bones  of  the  pelvis ;  in  the  Phytophaga  the 
glans  is  complicated,  but  in  the  Zoophaga  it  is 
of  a  simple  elongated  fusiform  shape :  in  all 
the  species  it  is  provided  with  a  prepuce. 

[According  to  Hunter,  the  parts  of  generation 
in  both  sexes  of  this  order  of  animals  come 
nearer  in  form  to  those  of  the  Ruminants  than 
of  any  others;  and  this  similarity  is,  perhaps, 
more  remarkable  in  the  female  than  in  the  male; 
for  their  situation  in  the  male  must  vary  on 
account  of  the  modification  of  the  external 
form  of  the  body. 

The  testicles  (a,  a^figs.  277,  278)  retain  the 
situation  in  which  they  were  formed,  as  in 
those  quadrupeds  in  which  they  never  come 
down  into  the  scrotum.  They  are  situated 
near  the  lower  part  of  the  abdomen,  one  on 
each  side,  upon  the  two  great  depressors  of  the 
tail.  At  this  part  of  the  abdomen,  the  testicles 
come  in  contact  with  the  abdominal  muscles 
anteriorly. 

The  vasa  deferentia  (c,  c)  pass  directly  from 
the  epididymis  (6,  b}  behind  the  bladder  (d,  d) 
or  between  it  and  the  rectum  (e)  into  the 
urethra  (f)  ;  and  there  are  no  bags  similar  to 
those  called  vesiculae  seminales  in  certain  other 
animals. 

The  structure  of  the  penis  is  nearly  the 
same  in  them  all,  and  formed  much  upon  the 
same  principle  as  in  the  quadruped.  It  is 
made  up  of  two  crura  (g,  g),  uniting  into  one 
corpus  cavernosum,  and  the  corpus  spongiosum 
seems  first  to  enter  the  corpus  cavernosum. 
In  the  Porpoise,  at  least,  the  urethra  is  found 
nearly  in  the  centre  of  the  corpus  cavernosum  ; 
but  towards  the  glans  seems  to  separate  or 

*  Philos.  Trans.  1787,  p.  390. 


592 


CETACEA. 


Fig.  277. 


Mak  Organs  of  a  Porpesse. 

emerge  from  it,  and  becoming  a  distinct  spongy 
body,  runs  along  its  under  surface,  as  in  qua- 
drupeds (A).  The  corpus  cavernosum  in  some 
is  broader  from  the  upper  part  to  the  lower 
,than  from  side  to  side;  but  in  the  Porpoise 
~  (jig-  277)  it  has  the  appearance  of  being 
round,  becoming  smaller  forwards,  so  as  to 
terminate  almost  in  a  point  some  distance  from 
the  end  of  the  penis.  The  glans  does  not 
spread  out  as  in  many  quadrupeds,  but  seems 
to  be  merely  a  plexus  of  veins  covering  the 
anterior  end  of  the  penis,  yet  is  extended  a 

Fig.  278. 


good  way  further  on,  and  is  in  some  not  more 
than  one  vein  deep. 

The  crura  penis  are  attached  to  two  bones, 
which  are  nearly  in  the  same  situation  and  in 
the  same  part  of  the  pelvis  as  those  to  which 
the  penis  is  attached  in  quadrupeds;  but  these 
bones  are  only  for  the  insertion  of  the  crura, 
and  not  for  the  support  of  any  other  part,  like 
the  pelvis  in  those  animals  which  have  poste- 
rior extremities,  neither  do  they  meet  at  the 
fore  part,  or  join  the  vertebrae  of  the  back. 

The  erectores  penis  (g,  g,  fig.  277)  are  very 
strong  muscles,  having  an  origin  and  insertion 
similar  to  those  of  the  human  subject. 

The  prostatic  portion  of  the  urethra  (f,  Jig. 
278)  is  surrounded  by  a  muscle  of  prodigious 
thickness  ( /c,  k),  destined  to  compress  and 
forcibly  expel  the  contents  of  that  part  of  the 
canal. 

The  acceleratores  muscles  (I)  are  likewise 
very  strong ;  and  there  is  a  pair  of  strong  and 
long  muscles  (m,  Jig.  277)  arising  from  the 
anus,  and  passing  forwards  to  the  bulb  of  the 
penis,  that  run  along  the  under  surface  of  the 
urethra,  and  are  at  last  lost  or  inserted  in  the 
corpus  spongiosum.  These  muscles  draw  the 
penis  into  the  prepuce,  and  throw  that  part  of 
the  penis  that  is  behind  its  insertion  into  a 
serpentine  form.  These  muscles  are  common 
to  most  animals  that  draw  back  the  penis  into 
what  is  called  the  sheath,  and  may  be  called 
the  retractores  penis. 

The  female  organs  in  the  Phytophagous 
Cetacea  have  been  described  by  Steller  as 
they  exist  in  the  Rytina,  and  by  Home  in 
the  Dugong;  the  latter  author  has  given  a 
figure  of  the  uterus  with  part  of  the  vagina : 
(see  fig.  279.)  In  both  species  the  vagina  (a) 
is  characterized  by  the  longitudinal  rugae  of 
its  inner  surface.  The  body  of  the  uterus  (c) 
commences  by  a  single  os  tincae  (6)  in  the 


Fig.  279. 


Mule  Organs  of  a  Dolphin. 


Uterus  of  the  Ditgong. 

Dugong,  and  gives  off  the  cornua  uteri  (d,  d) 
at  right  angles.*  The  structure  of  the  Fallo- 
pian tubes  and  ovaries  is  not  described.  Steller 
states  that  in  the  llytina  they  resemble  those  of 
the  Mare.  The  vulva  he  describes  as  of  a  tri- 
angular form,  with  the  clitoris,  which  is  of  a 
gristly  texture,  and  an  inch  and  a  half  long, 

*  See  Home,  in  Phil.  Trans.  1820,  p.  321. 


CETACEA. 


593 


situated  at  the  anterior  broad  part  of  the  open- 
ing, which  is  eight  inches  anterior  to  the  anus. 

lu  all  the  females  of  the  zoophagous  tribe 
of  Cetacea  which  Hunter  examined,  the  parts 
of  generation  were  very  uniformly  the  same ; 
consisting  of  the  external  opening,  the  vagina, 
the  body  and  two  horns  of  the  uterus,  Fallopian 
tubes,  fimbriae,  and  ovaria. 

"  The  external  opening  is  a  longitudinal  slit, 
or  oblong  opening,  whose  edges  meet  in  two 
opposite  points,  and  the  sides  are  rounded  off, 
so  as  to  form  a  kind  of  sulcus.  The  skin  and 
parts  on  each  side  of  this  sulcus  are  of  a  looser 
texture  than  on  the  common  surface  of  the 
animal,  not  being  loaded  with  oil,  and  allow- 
ing of  such  motion  of  one  part  on  another  as 
admits  of  dilatation  and  contraction.  The  va- 
gina passes  upwards  and  backwards  towards 
the  loins,  so  that  its  direction  is  diagonal  re- 
specting the  cavity  of  the  abdomen,  and  then 
divides  into  the  two  horns,  one  on  each  side  of 
the  loins ;  these  afterwards  terminating  in  the 
Fallopian  tubes,  to  which  the  ovaria  are  at- 
tached. From  each  ovarium  there  is  a  small 
fold  of  the  peritoneum,  which  passes  up  to- 
wards the  kidney  of  the  same  side,  as  in  most 
quadrupeds. 

"  The  inside  of  the  vagina  is  smooth  for  about 
one-half  of  its  length,  and  then  begins  to  form 
something  similar  to  valves  projecting  towards 
the  mouth  of  the  vagina,  each  like  an  os  tincae  : 
these  are  about  six,  seven,  eight,  or  nine  in 
number.  Where  they  begin  to  be  formed,  they 
hardly  go  quite  round,  but  the  last  are  com- 
plete circles.  At  this  part,  too,  the  vagina 
becomes  smaller,  and  gradually  decreases  in 
width  to  its  termination.  From  the  last  pro- 
jecting part,  the  passage  is  continued  up  to  the 
opening  of  the  two  horns,  and  the  inner  sur- 
face of  this  last  part  is  thrown  into  longitudinal 
rugse,  which  are  continued  into  the  horns. 
Whether  this  last  part  is  to  be  reckoned  com- 
mon uterus  or  vagina,  and  that  the  last  val- 
vular part  is  to  be  considered  as  os  tincae,  I  do 
not  know ;  but  from  its  having  the  longitudinal 
rugae,  I  am  inclined  to  think  it  is  uterus,  this 
structure  appearing  to  be  intended  for  dis- 
tinction. 

"  The  horns  are  an  equal  division  of  this  part; 
they  make  a  gentle  turn  outwards,  and  are  of 
considerable  length.  Their  inner  surface  is 
thrown  into  longitudinal  rugae,  without  any 
small  protuberances  for  the  cotyledons  to  form 
upon,  as  in  those  of  ruminating  animals ; 
and  where  they  terminate  the  Fallopian  tubes 
begin. 

"  In  the  Bottle-nose  Whale  (Delphinus  Tur- 
sio),  where  the  Fallopian  tubes  opened  into 
the  horns  of  the  uterus,  they  were  surrounded 
by  pendulous  bodies  hanging  loose  in  the 
horns. 

"  The  Fallopian  tubes,  at  their  termination  in 
the  uterus,  are  remarkably  small  for  some  in- 
ches, and  then  begin  to  dilate  rather  suddenly; 
and  the  nearer  to  the  mouth  the  more  this  dila- 
tation increases,  like  the  mouth  of  a  French 
horn,  the  termination  of  which  is  five  or  six 
inches  in  diameter.  They  are  very  full  of  lon^ 
gitudinal  rugae  through  their  whole  length. 


"  The  ovaria  are  oblong  bodies,  about  five 
inches  in  length;  one  end  attached  to  the 
mouth  of  the  Fallopian  tube,  and  the  other 
near  to  the  horn  of  the  uterus.  They  are  irre- 
gular on  their  external  surface,  resembling  a 
capsula  renalis  or  pancreas.  They  have  no 
capsula  but  what  is  formed  by  the  long  Fallo- 
pian tube. 

"  How  the  male  and  female  copulate  I  do  not 
know;  but  it  is  alleged  that  their  position  in 
the  water  is  erect  at  that  time,  which  I  can 
readily  suppose  maybe  true;  for  otherwise,  if 
the  connexion  is  long,  it  would  interfere  with 
the  act  of  respiration,  as  in  any  other  position 
the  upper  surface  of  the  heads  of  both  could 
not  be  at  the  surface  of  the  water  at  the  same 
time.  However,  as  in  the  parts  of  generation 
they  most  resemble  those  of  the  ruminating 
kind,  it  is  possible  they  may  likewise  resemble 
them  in  the  duration  of  the  act  of  copulation, 
for  I  believe  all  the  ruminants  are  quick  in 
this  act. 

"  Of  their  uterine  gestation  I  as  yet  know 
nothing,  but  it  is  very  probable  that  they  have 
only  a  single  one  at  a  time,  there  being  only 
two  nipples.  This  seemed  to  be  the  case  with 
the  Bottle-nose  Whale,  caught  near  Berkeley, 
which  had  been  seen  for  some  days  with  one 
young  one  following  it,  and  they  were  both 
caught  together. 

"  The  glands  for  the  secretion  of  milk  are 
two,  one  on  each  side  of  the  middle  line  of  the 
belly  at  its  lower  part.  The  posterior  ends, 
from  which  go  out  the  nipples,  are  on  each 
side  of  the  opening  of  the  vagina  in  small  sulci. 
They  are  flat  bodies  lying  between  the  external 
layer  of  fat  and  abdominal  muscles,  and  are  of 
considerable  length,  but  only  one-fourth  of  that 
in  breadth.  They  are  thin,  that  they  may  not 
vary  the  external  shape  of  the  animal,  and  have 
a  principal  duct,  running  in  the  middle  through 
the  whole  length  of  the  gland,  and  collecting 
the  smaller  lateral  ducts,  which  are  made  up 
of  those  still  smaller.  Some  of  these  lateral 
branches  enter  the  common  trunk  in  the  direc- 
tion of  the  milk's  passage,  others  in  the  con- 
trary direction,  especially  those  nearest  to  the 
termination  of  the  trunk  in  the  nipple.  The 
trunk  is  large,  and  appears  to  serve  as  a  reser- 
voir for  the  milk,*  and  terminates  externally  in 
a  projection,  which  is  the  nipple.  The  lateral 
portions  of  the  sulcus  which  incloses  the  nipple 
are  composed  of  parts  looser  in  texture  than 
the  common  adipose  membrane,  which  is  pro- 
bably to  admit  of  the  elongation  or  projection 
of  the  nipple.  On  the  outside  of  this  there  is 
another  small  fissure,  which  I  imagine  is  like- 
wise intended  to  give  greater  facility  to  the 
movements  of  all  these  parts.  The  milk  is 
probably  very  rich ;  for  in  that  caught  near 
Berkeley  with  its  young  one,  the  milk,  which 
was  tasted  by  Mr.  Jenner,  and  Mr.  Ludlow, 
surgeon,  at  Sodbury,  was  rich  like  cow's  milk 
to  which  cream  had  been  added. 

"  The  mode  in  which  these  animals  must 


*  The  description  of  this  structure  has  lately 
been  reproduced  as  a  new  discovery  by  Geoffroy 
St.  Hilaire. 


594 


CHEIROPTERA. 


suck  would  appear  to  be  very  inconvenient  for 
respiration,  as  either  the  mother  or  young  one 
will  be  prevented  from  breathing  at  the  time, 
their  nostrils  being  in  opposite  directions,  there- 
fore the  nose  of  one  must  be  under  water,  and 
the  time  of  sucking  can  only  be  between  each 
respiration.  The  act  of  sucking  must  likewise 
be  different  from,  that  of  land  animals ;  as  in 
them  it  is  performed  by  the  lungs  drawing  the 
air  from  the  mouth  backwards  into  themselves, 
which  the  fluid  follows,  by  being  forced  into 
the  mouth  from  the  pressure  of  the  external  air 
on  its  surface;  but  in  this  tribe,  the  lungs 
having  no  connexion  with  the  mouth,  sucking 
must  be  performed  by  some  action  of  the 
mouth  itself,  and  by  its  having  the  power  of 
expansion." 

Much  stress  has  recently  been  laid  on  the 
supposed  existence  which  the  muscles  sur- 
rounding the  mammary  gland  afford  in  the  act 
of  suckling  by  compressing  the  gland  and 
ejaculating  the  milk  accumulated  in  the  dilated 
receptacle  above  described  ;  but  when  we  con- 
sider how  great  the  pressure  of  the  surrounding 
water  must  be  upon  the  extended  surface  of  the 
mammary  gland,  we  may  readily  conceive  that 
when  the  nipple  is  grasped  by  the  mouth  of  the 
young,  and  the  pressure  removed  from  it  by 
the  retraction  of  the  tongue,  the  milk  will 
be  expelled  in  a  copious  stream  by  means  of 
the  surrounding  pressure  alone,  independently 
of  muscular  aid. 

The  intimate  structure  of  the  mammary  gland 
in  the  Zoophagous  Cetacea  is  essentially  the 
same  as  in  the  Ornithorhynchus,  being  compo- 
sed of  an  innumerable  quantity  of  small  elon- 
gated ccecal  tubes ;  these  are,  however,  shorter 
than  in  the  Ornithorhynchus,  and  their  glandu- 
lar parietes  are  firmer ;  they  are  well  shown  in 
the  figure  of  the  mammary  gland  of  a  young 
Piked  Whale,  ( Baltfnoptera  Rostrata,J  given 
by  Miiller  in  his  pi.  xvii.  Jig.  2,  and  according 
to  that  author  present,  after  the  Ornithorhyn- 
chus, the  simplest  structure  of  the  mammary 
gland  in  the  entire  mammiferous  series  of  ani- 
mals.] 

BIBLIOGRAPHY.— Aristotle,  Historia  de  animali- 
bus.  Bartholinus,  Cetorum  genera,  Historia  anato- 
mica,  Cent.  iv.  p.  272-285;  De  oculo  Balaenas  et 
Dentibus,  in  Acta  Hafniens.  vol.  ii.  p.  67-70;  De 
Unicornu  observationes  novse,  12mo.  1645.  Achre- 
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de  Cetis,  Aboae,  1683,  8vo.  Ray,  An  account  of 
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lainologianova,  &c.  Edinb.  1692,  4to.  ;  Scotia  illus- 
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in  Klein  Hist,  piscium  naturalis,  p.  24-32.  Ticho- 
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Whales  ;  with  a  particular  account  of  the  ambergris 
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Steller,  De  Bestiis  marinis,  Nouveaux  Memoires  de 
1'Academie  de  Petersbourg^  t.  ii.  1751.  Daubenton, 
Descriptions  des  tetes  de  Lamantins  et  de  Dugong, 
Hist.  Nat.  de  Buffon,  t.  xiii.  1765.  Linnaeus, 
Systema  Naturae,  Ed.  xii.  1766.  Pennant,  Brit. 


Zoology,  1776.  Fabricius,  (Otho,)  Fauna  Gioen- 
landica,  1780.  Pallas,  Spicilegia  Zoologica,  1767  to 
1780.  Hunter,  Observations  on  the  structure  and 
O2conomy  of  Whales,  Philos.  Trans.  1787.  Baussard, 
Memoire  sur  un  Cetace  echoue  pres  de  Honfleur, 
Journal  de  Physique,  1789.  Cuvier,  Geo.  Sur  les 
narines  des  Cetaces,  Bulletin  des  Sciences  pur  la 
SocietePhilomathique,  Juillet,1797;  Le9ons  d'Ana- 
tomie  Comparee,  torn.  i.  v.  1799-1804;  Recherches 
sur  les  Ossemens  Fossiles,  4to.  2d  ed.  t.  v.  pt.  i. 
1823;  Regne  Animal,  &c.  1817,  2d  ed.  1829. 
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Account  of  the  Balaena  Mysticetus,  &c.,  Wernerian 
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(  The  preceding  article  has  been  derived  from  the  work 
last  named  in  the  Bibliography,  with  the  addition  of 
the  extracts  from  Mr.  Hunter's  papers  and  the  other 
passages  included  between  brackets. ) 

(F.  Cuvier.) 


C  HEI RO  PTERA,  (from  %B  »?,  manus,  wrego  v, 
ala,)  Bats,  Fr.  Chauvesouris,Germ.  Fledermdu- 
ser,  an  order  of  mammiferous  quadrupeds, 
consisting  of  such  as  have  a  generally  in- 
sectivorous type  of  dentition,  with  the  extremi- 
ties connected  together  by  an  aliform  expansion 
of  the  integuments,  for  the  purpose  of  flight. 
The  question  whether  this  group,  as  well  as 
that  of  the  CARNIVORA  and  that  of  the  IN- 
SECTIVORA,  ought  to  be  considered  as  forming 
a  single  order  according  to  the  method  of 
Cuvier,  has  been  already  sufficiently  adverted 
to  under  the  head  CARNIVORA;  and  it  needs 
only  to  be  now  observed  that  if  there  were 
sufficient  ground  for  giving  to  the  last-men- 
tioned group  a  separate  consideration,  either 
on  account  of  expediency  and  convenience, 
or  on  that  of  natural  arrangement,  the  same 


CHEIROPTERA. 


595 


reasons  hold  good,  in  the  present  case,  in  an 
equal,  if  not  a  superior  degree. 

The  distinctions  by  which  the  present  order 
is  separated  from  all  others  are  so  marked, 
and  the  general  similarity  in  the  organization  of 
its  component  groups  is  so  striking,  as  greatly 
to  facilitate  and  shorten  the  necessary  detail 
of  the  organization. 

There  appears  to  be  a  great  and  obvious 
objection  to  the  usual  location  of  the  remark- 
able genus  Galeopithecus  amongst  the  Cheiro- 
ptera ;  there  are  so  many  important  parts  of 
its  organization  in  which  it  clearly  resembles 
the  more  insectivorous  forms  of  the  Quadru- 
jtiana,  not  only  in  the  peculiarities  of  its 
osteology,  but  in  many  other  not  less  essential 
points,  that  I  have  preferred  following  the 
change  suggested  by  Blainville,  and  subse- 
quently adopted  by  Temminck,  to  the  arrange- 
ment of  Cuvier  and  of  most  other  zoologists. 
It  may  undoubtedly  be  considered  as  an  escu- 
lent form,  leading  from  the  Quadrumanous 
order,  by  the  Makis,  &c.  to  the  present  group ; 
but  it  cannot  but  be  acknowledged  by  any 
one  who  has  attentively  marked  its  anatomical 
structure,  that  the  affinity  of  this  genus  to  the 
Quadrumana  is  more  intimate  than  that  by 
which  it  approaches  the  Bats ;  though  perhaps 
it  would  be  going  too  far  to  say,  with 
Temminck,  that  it  bears  the  same  relation 
to  the  Quadrumana  as  Petaurista  to  the  Mar- 
supiata,  or  Pteromys  to  the  Rodentia.  The 
latter  genera  are  not  even  on  the  confines 
of  their  respective  orders,  nor  do  they  offer 
any  important  aberration  from  the  typical  struc- 
ture; but  in  the  present  case  there  are  several 
characters  which  indicate  an  interesting  ap- 
proach towards  the  order  from  which  it  has 
very  properly  been  removed. 

Omitting,  then,  the  genus  Galeopithecus, 
the  Cheiroptera  form,  without  perhaps  a  single 
exception,  the  most  distinctly  circumscribed 
and  natural  group  to  be  found  in  the  whole 


class  of  the  Mammifera.  The  characters  by 
which  the  order  thus  restricted  is  distinguished 
are  as  follow  : — 

General  form  disposed  for  flight;  an  ex- 
pansion of  the  integument  stretched  between 
the  four  members,  and  the  fingers  of  the  an- 
terior extremities,  which  are  greatly  elongated 
for  that  purpose ;  the  flying  membrane  naked, 
or  nearly  so,  on  both  sides.  Mamma  pectoral, 
clavicles  very  robust ;  fore-arm  incapable  of 
rotation,  in  consequence  of  the  union  of  the 
bones  of  which  it  is  composed. 

The  Cheiroptera  consist  of  two  distinct 
groups;  of  which  the  first,  containing  the 
genera  Pteropus  and  Cephalotes,  is  frugivorous, 
and  distinguished  by  the  molar  teeth  being 
obliquely  truncated  and  longitudinally  grooved, 
and  by  the  existence  of  a  third  phalanx,  which 
is  in  general  provided  with  a  little  nail  on  the 
index  or  second  finger,  and  by  the  absence  or 
rudimentary  condition  of  the  tail.  The  second, 
consisting  of  the  insectivorous  bats,  (Chauve- 
souris  vraies,  Cuv.  Vesper  tilionida,  Gray,) 
have  the  molares  furnished  with  acute  points, 
similar  to  those  of  other  insectivora. 

Osteology. — The  evident  object  in  the  general 
structure  of  the  skeleton  of  the  Cheiroptera 
(jig.  280)  is  to  combine  as  great  a  degree 
of  lightness  as  possible  with  great  extension 
of  the  anterior  extremities,  for  the  purposes 
of  flight.  The  general  form  of  the  head  differs 
in  the  two  grand  divisions  of  the  Cheiroptera 
by  the  different  lengths  of  the  cranium ;  and 
this  diversity  is  exactly  conformable  with  that 
which  exists  in  other  families.  The  frugivorous 
group  (jig.  281,  282,  283)  has  a  much  more 
elongated  form  than  the  insectivorous  (fig. 
284,  285,  286),  arising  principally,  though 
not  wholly,  from  the  form  of  the  maxillary 
and  intermaxillary  bones. 

The  cranium  is  generally  rounded,  and  rather 
broad.  The  posterior  aspect  more  or  less  con- 
vex in  different  groups ;  in  some  overhanging 


Skeleton  of  Pterojtiu. 


596 


CHEIROPTERA. 


Fig.  281. 


the  occipital  foramen,  in  others  not  so.  The 
occipital  crest  is  triangular,  stronger  in  the 
insectivorous  than  in  the  frugivorous  form. 
In  many  there  is  also  a  longitudinal  crest. 
The  face  is  broad.  The  orbits  are  not  com- 
plete in  either  group,  and  the  temporal  fossa 
is  large,  but  the  zygoma  in  many  very  slender  ; 
in  some  it  is  horizontal,  in  others  slightly 
convex  above.  The  nasal  opening  is  very 
considerable;  and  in  many  whole  genera,  as 
in  Rhinolophus,  in  Plecotus,  and  several  others, 
in  consequence  of  the  intermaxillary  bones  not 
meeting  each  other,  it  is  not  closed  at  the 
lower  part.  In  the  genus  Pteropus,  and  some 
others,  as  is  seen  in  fg.  282,  283,  though  the 
intermaxillary  bones  meet  in  front,  yet,  as  the 
arch  is  very  small  and  narrow  from  before 
backwards,  the  palatine  foramina  unite  and 
form  a  single  large  opening. 

From  the  extreme  thinness  of  the  cranial 
bones,  the  internal  surface  corresponds  exactly 
with  the  external,  and  there  is  no  vestige  of 
a  bony  tentorium,  which  is  so  strong  in  many 
of  the  Carnivora. 

The  frontal  bone  in  the  genus  Pteropus 
presents  a  prominent  orbitar  process  ;  it  re- 
sembles that  of  Man,  and  of  the  Quadrumana, 
in  the  circumstance  of  the  two  portions  be- 
coming early  united.  The  parietals,  also, 
unlike  those  of  the  examples  just  named,  form 
but  a  single  bone. 

The  temporal  bone  has  a  very  extensive 
development  of  its  acoustic  portion ;  a  cha- 
racter which  is  of  the  utmost  importance  to 
their  peculiar  habits,  as  the  organ  of  hearing 


Fig.  282. 


Fig.  283. 


requires  to  be  extensive  in  those  animals  which 
prey  by  night,  and  especially  in  such  as  feed 
upon  insects  and  pursue  them  on  the  wing. 

The  occipital  bone  is  remarkable  from  the 
narrowness  of  its  body,  the  transverse  direction 
of  the  condyles,  the  short,  thin,  and  convex 
form  of  its  squamous  portion,  and  particularly 
from  the  unparalleled  proportionate  size  of  the 
occipital  foramen,  which  is  nearly  vertical  and 
rounded. 


Fig.  284. 


Fig.  285. 


Fig.  286. 


Cranium  of  Pteropus. 


Cranium  of  Phyllostoma. 

The  jugal  bone  is  small  in  most  of  the  bats 
and  very  strait. 

The  superior  maxillary  bone  is  considerably 
elongated  in  this  order,  particularly  in  the 
frugivorous  genera.  The  difference  in  this 
respect  which  exists  between  the  frugivorous 
and  insectivorous  forms  is  shewn  in  the  cranium 
of  a  Pteropus  belonging  to  the  former  (Jig. 
281,  282,  283),  and  a  Phyllostoma  to  the 
latter  group  (Jig.  284,  285,  286).  In  the 
former  case,  the  portion  occupied  by  the  teeth 
fully  equals  in  length  the  portion  of  the  cranium 
posterior  to  it ;  in  the  latter  it  is  little  more 
than  as  two  to  three.  The  number  of  teeth  con- 
tained in  this  bone  varies  considerably.  There 
is,  however,  always  a  single  canine  tooth  on 
each  side,  which  is  tolerably  robust  and  sharp. 
The  molares  of  the  insectivorous  Bats  are 
always  shorter  than  those  of  the  frugivorous, 
and  are  furnished  with  sharp  points,  the  latter 
being  truncated  and  longitudinally  grooved. 
They  vary  in  number  from  §  to  §,  or  f . 

The  intermaxillary  bones  are  always  very  small 
and  short ;  they  contain  small  incisores,  varying 
in  number  according  to  the  genera,  from  two 
to  four  in  the  upper,  and  in  the  lower  jaw  from 
two  to  six,  there  being  always  either  the  same 
numberin  the  two  jaws,  or  two  more  in  the  lower 
than  in  the  upper ;  thus  there  is  always  one 
of  the  following  formulae— f  f  $  |.  The  articu- 
lation of  the  lower  jaw  is  transverse.  The 
ascending  ramus,  with  its  coronoid  process,  is 
large  and  strong,  rising  very  high  above  the 
level  of  the  condyle. 

The  vertebral  column. —  The  cervical  verte- 
bra are  in  general  very  little  raised,  but  they 
are  developed  laterally,  so  as  to  present  the 
broadest  portion  of  the  whole  vertebral  column, 


CHEIROPTERA. 


597 


and  the  spinous  processes  are  wanting  from 
the  second  to  the  sixth  vertebra.  The  Atlas 
is  large,  the  dentata  small,  and  its  spinous 
process  inconsiderable.  The  dorsal  vertebra 
are  of  a  very  simple  construction ;  they  are 
almost  without  spinous  processes,  which  are 
replaced  by  a  small  tubercle :  the  bodies  are, 
however,  much  compressed  at  the  sides,  so  as 
to  form  a  sort  of  crest.  The  vertebral  canal 
is  veiy  large  in  this  region.  These  vertebrae 
are  twelve  in  number  in  both  forms,  excepting 
in  some  species  of  the  single  genus  Vespertilio, 
in  which  they  are  only  eleven.  The  lumbar 
vertebra  retain  the  peculiar  characters  which 
have  been  mentioned  as  belonging  to  the 
dorsal.  They  are  elongated,  and  still  almost 
devoid  of  spinous  processes ;  they  are  also 
compressed  into  a  sort  of  continuous  crest. 
The  number  of  these  vertebrae  is  four  in 
Pteropus,  five  in  Phyllostoma  and  Vespertilio, 
six  in  Rhinolophus,  seven  in  Noctula. 

The  sacrum  is  particularly  elongated  and 
narrow,  and  the  spinous  processes  large.  The 
number  of  sacral  vertebra  varies  much.  In 
Pteropus  (fig.  280)  there  is  but  one.  In  the 
other  genera  they  are  either  three  or  four.  In 
Pteropus  the  sacrum  is  united  at  its  extremity 
to  the  tuberosities  of  the  ischium. 

The  coccygeal  vertebra  are  slender,  elon- 
gated, and  nearly  cylindrical ;  the  tail  being 
always  included  within  the  flying  membrane, 
the  only  use  of  this  part  is  to  assist  in  sup- 
porting the  interfemoral  portion  of  that  mem- 
brane. In  most  the  tail  reaches  to  its  margin, 
in  some  much  beyond,  in  others  only  half-way, 
and  in  Pteropus  (Jig.  280)  there  is  not  the  least 
appearance  of  a  tail,  there  is  not  even  a  rudi- 
ment of  acoccygeal  bone.  The  number  of  these 
vertebrae  is  but  six  in  Noctula,  twelve  in  Ves- 
pertilio  and  some  others. 

The  number  of  vertebrae  in  the  whole  co- 
lumn is  said  to  be  less  in  Pteropus  than  in  any 
other  mammiferous  animal,  being  only  twenty- 
four,  namely,  7C+1 2  D+4L-HS=24. 

The  ribs  are  the  same  in  number  as  the  dorsal 
vertebra.  The  first  rib  is  very  short  and 
remarkably  broad,  and  its  cartilage,  which  is 
ossified,  is  still  more  so.  The  rest  of  the  ribs 
follow  the  usual  variations  of  form. 

The  Bats  are  remarkable  for  the  extraordinary 
proportional  length  of  their  ribs,  in  which  they 
probably  exceed  all  other  Mammifera. 

The  sternum  is  altogether  greatly  developed 
in  the  whole  of  this  order.  Its  length  is  con- 
siderable, and  this  circumstance,with  the  length 
of  the  ribs,  tends  to  afford  a  great  protection 
to  the  thorax  in  the  violent  movements  re- 
quired by  the  act  of  flight.  But  the  most  re- 
markable peculiarity  exhibited  in  the  structure 
of  this  part,  is  the  extraordinary  lateral  deve- 
lopment of  the  anterior  portion  of  this  bone, 
termed  the  manubrium.  This  expansion  is 
conspicuous  in  all  the  Bats,  and  appears  to  be 
intended  to  afford  the  strongest  possible  attach- 
ment for  the  clavicles,which  are  also  very  much 
developed.  In  the  genus  Rhinolophus  (the 
Horse-shoe  Bat),  this  expansion  seems  to  have 
reached  its  maximum  of  development.  Ets 
breadth  is  four  times  as  great  as  its  length,  and 


yet  it  is  nearly  as  long  as  the  whole  remaining 
portion  of  the  sternum.  The  inferior  surface 
of  the  manubrium  is  also  furnished  with  a 
crest,  which  is  continued,  though  much  smal- 
ler, on  the  next  piece  of  the  sternum ;  it  varies 
in  size  in  the  different  genera.  The  remaining 
bones  composing  the  sternum  are  of  nearly  equal 
size. 

The  anterior  extremity  is  the  part  of  the 
skeleton  which  in  the  true  Cheiroptera  offers 
the  most  remarkable  deviation  from  the  nor- 
mal form,  especially  in  the  metacarpal  and  pha- 
langeal  bones. 

The  clavicle,  from  the  extensive  motion  of 
the  anterior  extremities,  requires  to  be  much 
elongated  in  these  animals ;  some  of  which  in 
fact  exhibit  proportionally  a  greater  develop- 
ment of  this  bone  than  is  to  be  found  in  any 
other  order.  It  is  always  arched  above  and 
intimately  articulated  both  to  the  scapula  and 
to  the  sternum,  and  in  some  species  is  half  as 
long  as  the  greatly  elongated  humerus.  As  far 
as  I  have  had  an  opportunity  of  observing, 
the  clavicle,  as  well  as  the  other  portions  of 
this  extremity,  is  more  developed  in  the  in- 
sectivorous than  in  the  frugivorous  Bats,  for  the 
very  obvious  reason  that  the  former  require 
more  extensive  powers  of  flight  in  the  pursuit 
of  their  swift  and  active  prey,  than  the  latter 
in  merely  flying  from  place  to  place,  in  search 
of  their  stationary  food. 

The  scapula  is  also  developed  to  the  greatest 
extent,  and  particularly  in  the  insectivorous 
Bats.  It  is  greatly  elongated  towards  the  base 
and  posterior  angle,  which  in  some  species 
reaches  nearly  to  the  last  rib.  The  inner 
surface  is  very  concave,  and  the  fossa  above 
and  below  the  spine  are  deep,  for  the  attach- 
ment of  the  powerful  muscles  which  are  in- 
serted to  it. 

The  humerus  is  very  long,  slender,  and  cy- 
lindrical, as  may  be  observed  in  the  skeleton 
of  Pteropus  in  Jig.  280.  The  head  of  the  bone 
is  round  and  large.  The  whole  anterior  part 
of  the  inferior  articulation  or  elbow-joint  cor- 
responds to  the  head  of  the  radius. 

The  fore-arm  consists,  as  in  the  other  mam- 
mijera,  of  the  radius  and  the  ulna.  The  latter 
bone  is,  however,  in  all  the  Cheiroptera  ex- 
ceedingly small,  and  in  some  merely  rudimen- 
tary. In  several  species  of  Vespertilio,  for 
instance,  it  forms  nothing  more  than  a  flat 
process,  only  partially  separated  from  the 
radius.  In  the  example  shewn  at  fig.  280 
it  is  more  considerable  ;  but  even  here  it 
presents  nothing  more  than  a  small  styliform 
bone,  united  to  the  radius  at  the  head,  and 
diminishing  to  a  thin  point,  towards  the 
carpal  extremity;  the  olecranon  too  is  wholly 
wanting. 

The  radius,  like  the  other  bones  of  the  an- 
terior extremity,  is  remarkably  elongated,  and 
rather  robust.  The  absence  of  rotation  in  the 
forearm  of  these  animals  forms  an  admirable 
adaptation  to  their  habits.  Not  only  would 
the  pronation  and  supination  of  the  hand  be 
wholly  useless  to  them,  but  at  every  impulse 
of  their  flight  such  a  motion  would  deprive 
the  whole  limb  of  its  resistance  to  the  air,  of 


598 


CHEIROPTERA. 


it  would  require  the  constant  exertion  of  such 
a  degree  of  antagonizing  muscular  force  to 
prevent  it,  as  would  be  incompatible  with  the 
essential  structure  of  these  organs  of  flight. 

The  carpus  is  of  a  very  peculiar  structure. 
The  first  series  of  bones  consists  but  of  two ; 
one  very  large,  on  which  the  radius  rests,  and 
which  is  probably  formed  of  the  three  outer 
bones,  the  scaphoid,  the  semilunar,  and  the 
cuneiform  bones ;  the  other  extremely  small, 
which  is  undoubtedly  the  pisiform,  on  the  ulnar 
side. 

The  second  series  consists  of  the  four  bones 
of  which  it  is  usually  constituted. 

The  metacarpal  bones  and  phalanges  of  all 
the  fingers  excepting  the  thumb  are  extremely 
elongated.  They  extend  outwards  and  down- 
wards in  a  slightly  curved  direction  to  the 
margin  of  the  flying  membrane,  the  second 
finger  being  the  shortest  and  extending  to  the 
upper  angle  of  the  outer  margin,  the  third, 
fourth,  and  fifth  to  the  inferior  margin  of  the 
membrane.  There  is  a  slight  enlargement  at 
the  articulation  of  the  metacarpal  bones  with 
the  phalanges;  but  otherwise  these  bones  are 
extremely  slender  and  cylindrical.  The  thumb 
is  of  no  extraordinary  length,  and  the  ultimate 
phalanx  is  hooked  and  sustains  a  nail,  by 
which  the  animal  is  enabled  to  climb  on  any 
rough  perpendicular  surface,  or  to  suspend 
itself  from  some  projecting  part. 

The  pelvis  is  remarkably  strait,  rather  elon- 
gated, somewhat  wider  inferiorly.  The  ilia 
are  narrow  and  elongated ;  the  isc hia  in  several 
species,  instead  of  receding  from  each  other, 
approach  so  that  their  tuberosities  touch  each 
other,  and  in  some  instances  come  in  contact 
with  the  coccygeal  bones.  In  some  species  of 
Pteropus,  the  anterior  portion  of  the  ossa  pubis, 
instead  of  meeting  at  the  median  line,  recede 
more  or  less  from  each  other,  and  the  space  is 
filled  by  ligament.  In  some  species  there  is  a 
sexual  difference  in  this  respect ;  the  two  pubic 
bones  being  in  contact  in  the  male  and  sepa- 
rated in  the  female. 

The  sacrum  and  the  ilia  are  connected  by 
absolute  bony  union  at  an  early  period.  The 
femur  is  of  moderate  length,  slender  and  cy- 
lindrical. It  is  turned  outwards  and  upwards, 
so  that  the  side  which  is  usually  anterior  is 
directed  nearly  backwards.  The  tibia  offers 
no  peculiarity  which  requires  particular  notice. 
The  fibula  is  exceedingly  small,  slender, 
pointed  towards  its  femoral  extremity,  and  has 
this  singular  peculiarity,  that  it  does  not  rise 
to  the  head  of  the  tibia.  In  other  cases  where 
this  bone  is  defective,  it  is  at  its  inferior  ex- 
tremity, but  in  the  present  case  it  is  the  supe- 
rior portion  which  is  wanting.  As  the  femora 
are  directed  outwards,  the  leg-bones  are  in 
some  measure  turned  round,  so  that  the  fibula 
are  at  the  inner  side  of  the  tibia  and  a  little 
behind  them. 

The  foot  of  the  Cheiroptera  does  not  ex- 
hibit the  same  deviation  ;V  >  a  the  normal 
structure  which  we  have  seeni  n  the  hand.  On 
the  contrary,  it  is  not  extraordinarily  developed, 
and  the  different  parts  of  which  it  is  composed 
are  in  the  usual  relative  proportions. 


The  tarsus  is  composed  of  the  usual  bones. 
There  is  a  peculiarity  in  the  heel,  however, 
which  is  worthy  of  notice.  There  is  a  long, 
slender,  pointed,  bony  process  from  the  pos- 
terior part  of  the  foot  which  is  inclosed  within 
the  folds  of  the  margin  of  the  interfemoral 
membrane,  and  extends  about  half-way  to  the 
tail.  Whether  this  process  is  a  portion  of  the 
os  calcis,  according  to  Cuvier,  or  a  distinct 
bone  according  to  Daubenton,  it  is  perhaps 
difficult  to  decide ;  but  the  opinion  of  Meckel 
is  probably  the  correct  one,  that  it  is  nothing 
more  than  a  development  of  the  tuberosity  of 
that  bone,  remaining  disunited  from  its  body. 

Themetatarsal  bones  are  rather  short,  slender, 
and  of  nearly  equal  length. 

The  phalanges  of  the  five  toes  are  nearly 
equal,  the  inner  toe  reaching  almost  to  the 
same  length  as  the  others,  in  consequence  of 
the  greater  elongation  of  its  first  phalanx. 
The  ultimate  phalanges  are  furnished  with 
hooked  nails,  by  which  these  animals  constantly 
suspend  themselves  when  at  rest  with  the  head 
downwards. 

The  whole  of  this  structure  is  so  perfectly 
adapted  to  the  peculiar  habits  of  the  animals, 
as  to  require  no  comment.  The  great  deve- 
lopment of  the  ribs,  sternum,  and  scapula,  for 
the  attachment  of  strong  muscles  of  flight,  the 
length  and  strength  of  the  clavicle,  the  exten- 
sion of  all  the  bones  of  the  anterior  extremities, 
all  admirably  tend  to  fulfil  their  obvious  end. 
The  existence  of  a  tail  for  the  support  and 
extension  of  the  interfemoral  membrane,  which 
is  found  in  the  insectivorous  Bats,  compared 
with  its  absence  or  comparative  inefficiency  in 
many  of  the  frugivorous,  also  points  out  an 
interesting  relation  to  the  different  habits  of  the 
two  groups,  the  former  structure  being  calcu- 
lated to  afford  a  powerful  and  effective  rudder 
in  guiding  their  rapid  and  varying  evolutions 
in  the  pursuit  of  their  insect  food. 

The  general  nervous  system  in  the  Cheiro- 
ptera does  not  exhibit  any  very  remarkable 
peculiarity,  but  some  of  the  organs  of  sense 
require  a  particular  notice. 

Organs  of  the  Senses. —  The  organ  of  vision 
is  principally  remarkable  for  its  diminutive 
size.  The  eye  in  many  of  the  insectivorous 
group,  in  which  the  external  ear  is  very  largely 
developed,  is  placed  within  the  margin  of  the 
auricle  and  almost  concealed  by  hair.  In  the 
frugivorous  group,  on  the  other  hand,  it  is 
of  the  usual  proportional  size.  The  organ 
of  hearing,  on  the  contrary,  though  in  the 
latter  forms  not  more  developed  than  in  most 
other  quadrupeds,  in  the  former  seems  to  take 
the  place  of  the  diminutive  organ  of  vision, 
being  greatly  extended  both  in  its  external  and 
internal  organization.  The  external  ear  in 
Pteropus  is  of  the  usual  form  and  dimensions, 
and  the  eminences  are  not  in  any  respect  extra- 
ordinary :  but  in  most  of  the  insectivorous  Bats 
the  conch  of  the  ear  is  enormously  large ;  in 
many  species  being  considerably  larger  and 
longer  than  the  head,  and  in  the  common  long- 
eared  Bat  of  this  country,  Plecotus  auritus,  it 
is  nearly  as  long  as  the  body.  The  tragus  is 
proportionally  larger  than  in  any  other  animals ; 


CHEIROPTERA. 


in  most  species  it  is  more  or  less  lanceolate  in 
its  form;  in  Vespertilio  spasma  it  is  forked, 
and  in  the  great  Bat  of  Britain,  Vespertilio 
noctula,  it  is  short,  blunted,  with  a  rounded 
head,  thickish,  and  I  have  observed  it  beset 
with  numerous  minute  glands,  which  do  not 
occur  in  those  species  having  the  thin  lan- 
ceolate form  of  this  part.  Its  use  is  probably 
to  prevent  the  rush  of  air  into  the  open  ear 
during  flight;  and  where  it  does  not  exist, 
as  in  the  Horse-shoe  Bats  (Rhinolophus),  its 
place  is  supplied  by  a  large  rounded  lobe  which 
is  capable  of  still  more  effectually  closing  the 
external  meatus. 

In  the  internal  ear  there  is  an  equal  diver- 
sity of  structure  in  the  two  groups  in  question. 
The  cochlea  is  particularly  developed  in  the 
insectivorous  group ;  being  much  larger  than 
the  semicircular  canals;  the  circumference  of 
that  of  Rhinolophus  is  no  less  than  four  times 
the  circumference  of  the  canals,  and  its  cavity 
exhibits  ten  times  the  diameter  of  one  of  them. 
In  Pteropus  this  disproportion  is  very  much 
less.  The  meatus  is  short  and,  as  well  as  the 
tympanic  cavity,  extremely  large  and  open. 

But  it  is  in  the  sense  of  touch  probably  that 
the  most  extraordinary  and  interesting  pecu- 
liarities are  to  be  observed.  Spallanzani  hav- 
ing observed  the  power  which  these  animals 
possess  of  flying  with  perfect  accuracy  in  the 
dark,  and  of  avoiding  every  obstacle  that  pre- 
sents itself  with  the  same  unerring  certainty  as 
in  the  light,  instituted  a  series  of  experiments, 
the  results  of  which  proved  that  bats  when 
deprived  of  sight  by  the  extirpation  of  the 
eyes,  and,  as  far  as  possible,  of  hearing  and 
smell  by  the  obliteration  of  the  external  pas- 
sages of  those  senses,  were  still  capable  of 
directing  their  flight  with  the  same  security 
and  accuracy  as  before,  directing  their  course 
through  passages  only  just  large  enough  to 
admit  them  without  coming  into  contact  with 
the  sides,  and  even  avoiding  numerous  small 
threads  which  were  stretched  across  the  room 
in  various  directions,  the  wings  never,  even 
by  accident,  touching  any  of  them.  These 
marvellous  results  led  him  to  believe  that  these 
animals  are  endowed  with  a  sixth  sense,  the 
immediate  operation  as  well  as  the  locality  of 
which  is,  of  course,  unknown  to  and  unap- 
preciable  by  us  :  but  the  sagacity  of  Cuvier* 
removed  the  mystery  without  weakening  the 
interest  of  these  curious  facts,  by  referring  to 
the  flying  membrane  as  the  seat  of  this  extra- 
ordinary faculty.  According  to  this  view  of 
the  subject,  the  whole  surface  of  the  wings  on 
both  sides  may  be  considered  as  an  enor- 
mously expanded  organ  of  touch,  of  the  most 
exquisite  sensibility  to  the  peculiar  sensation 
for  which  it  is  intended ;  and  it  is,  therefore, 
by  the  varied  modification  of  the  impulsion  of 
the  atmosphere  upon  this  surface,  that  the 
knowledge  of  the  propinquity  of  foreign  bodies 
is  communicated.  This  membrane  is  every 
where  furnished  with  oblique  or  transverse 
bands,  consisting  of  lines  of  minute  dots  re- 

*  Le9ons  d'Anatomie  Comparee,  t.  ii.  p  582. 


sembling  in  some  measure  strings  of  very  small 
glands  or  cutaneous  follicles.  May  there  not 
be  some  connexion  between  these  peculiar 
little  bodies  and  the  extraordinary  function  just 
described  ? 

The  tendency  to  an  extraordinary  develop- 
ment of  the  dermal  system  is  not  confined  to 
the  organs  now  mentioned,  of  the  senses  of 
touch  and  of  hearing.  The  organ  of  smell  is 
in  many  insectivorous  Bats,  as  in*  the  whole 
family  Rhinolophida:,  furnished  with  foli- 
aceous  appendages,  formed  of  the  integument 
doubled,  folded,  and  cut  into  the  most  curious 
and  grotesque  forms.  These  nasal  leaflets  are 
found  principally  or  exclusively  to  belong  to 
a  group,  the  habits  of  which  are  more  com- 
pletely lucifugous  and  retired  than  any  others ; 
they  are  found  in  the  darkest  penetralia  of 
caverns,  and  other  places  where  there  is  not 
even  the  imperfect  light  which  the  other  genera 
of  Bats  enjoy.  It  is  probable  that  this  deve- 
lopment of  skin  around  the  nose  is  intended 
to  give  increased  power  and  delicacy  to  the 
organ  of  smell,  as  well  as  to  regulate  the  access 
of  the  odoriferous  particles,  and  thus  to  super- 
sede the  sense  of  vision,  in  situations  where  the 
latter  would  be  unavailable. 

In  the  genus  Nycteris  a  curious  faculty  is 
observed,  namely,  the  power  of  inflating  the  sub- 
cutaneous tissue  with  air.  The  skin  adheres 
to  the  body  only  at  certain  points,  where  it  is 
connected  by  means  of  a  loose  cellular  mem- 
brane ;  it  is  therefore  susceptible  of  being  raised 
from  the  surface,  on  the  back  as  well  as  on  the 
under  parts.  These  large  spaces  are  filled  with 
air  at  the  will  of  the  animal,  by  means  of  large 
cheek  pouches,  which  are  pierced  at  the  bottom, 
and  thus  communicate  with  the  subcutaneous 
spaces  just  mentioned.  When  the  animal 
therefore  wishes  to  inflate  its  skin,  it  inspires, 
closes  the  nostrils,  and  then  contracting  the 
cavity  of  the  chest,  the  air  is  forced  through 
the  openings  in  the  cheek  pouches  under  the 
skin,  from  whence  it  is  prevented  from  returning 
by  means  of  a  true  sphincter,  with  which  those 
openings  are  furnished,  and  by  large  valves  on 
the  neck  and  back.  By  this  curious  me- 
chanism the  bat  has  the  power  of  so  com- 
pletely blowing  up  the  spaces  under  the  skin, 
as  to  give  the  idea,  as  Geoffrey  observes, fe  of  a 
little  balloon  furnished  with  wings,  a  head,  and 
feet." 

The  digestive  organs  of  the  Cheiroptera  ex- 
hibit as  distinct  a  division  into  the  two  prin- 
cipal groups  before-mentioned,  as  any  other 
part  of  their  anatomy.  The  teeth  have  been 
already  alluded  to,  and  the  characters  of  these 
important  organs,  important  as  indicating,  in 
the  most  unerring  manner,  the  nature  of  the 
food,  are  well-marked  in  the  two  groups.  The 
flattened  crowns  of  the  molares,  so  similar  to 
those  of  the  Quadrumana  which  are  found  to 
belong  to  the  frugivorous  Bats,  are  strikingly 
contrasted  with  the  many-pointed  tuberculous 
teeth  of  the  insect-feeders,  and  exhibit  an  in- 
teresting affinity  to  the  two  important  orders  of 
animals  to  which  the  Cheiroptera  may  be  con- 
sidered intermediate;  the  former  division  re- 


600 


CHYLIFEROUS  SYSTEM. 


ferring  evidently  to  the  Quadrumanous  type  in 
the  structure  of  the  teeth,  and  the  latter  to  the 
type  of  the  insectivora. 

The  tongue  presents  a  peculiarity  in  the 
genus  Phyllostoma,  which  is  worthy  of  being 
particularly  noted.  It  consists  of  a  number 
of  wart-like  elevations,  so  arranged  as  to  form 
a  complete  circular  suctorial  disk,  when  they 
are  brought  into  contact  at  their  sides,  which  is 
done  by  means  of  a  set  of  muscular  fibres, 
having  a  tendon  attached  to  each  of  the  warts. 
By  means  of  this  curious  sucker,  these  bats 
are  enabled  to  suck  the  blood  of  animals  and 
the  juice  of  succulent  fruits.  This  power  has 
been  attributed  by  mistake  to  some  of  the 
genus  Pteropus,  merely  because  their  tongue  is 
rough,  and  it  was  calculated  that  by  means  of 
such  a  surface  the  skin  may  have  been  abraded. 

The  stomach  is  no  less  indicative  of  the  nature 
of  the  aliment  than  the  teeth ;  offering,  in  the  Pte- 
ropus (fig.  287),  a  very  striking  affinity  to  that 


Fig.  287. 


of  many  true  vegetable  feeders  in  some  remote 
orders,  and  in  Plecotus  (Jig.  288),  as  complete 

Fig.  288. 


an  identity  with  that  of  the  carnivorous  type. 
In  the  former  the  oesophagus  swells  out  before 
it  enters  the  general  cavity,  and  that  dilatation, 
as  Home  observes,  appears,  from  its  structure, 
to  belong  to  the  stomach.  To  the  left  of  the 
esophagus  there  are  two  dilatations,  the  far- 
thest of  which  has  a  smooth  surface  and  thin 
coats  ;  the  other  is  furnished  with  several  deep 
longitudinal  rugae,  some  of  which  are  con- 
tinued from  similar  ones  in  the  oesophagus. 
Four  of  the  rugae  are  continued  towards  the 
pylorus,  giving  a  direction  to  the  food  in  that 
course;  about  one-third  of  the  stomach  to- 
wards the  pyloric  extremity  is  turned  back 
upon  itself,  and  the  pylorus  is  consequently 
placed  externally  close  to  the  entrance  of  the 
oesophagus.  At  the  pylorus  is  a  very  small 
opening  into  the  intestine,  which  when  con- 
tracted seems  scarcely  pervious  to  air.  Such 
is  the  complicated  form  of  the  stomach  in  the 
frugivorous  division ;  whilst  that  of  the  insect- 
feeders  is  as  simple  as  possible,  being  only 
divided  into  a  cardiac  and  a  pyloric  portion 
with  scarcely  the  slightest  contraction.  The 
intestines  present  a  no  less  marked  distinction. 
In  the  Pteropus  they  are  no  less  than  seven 
times  the  length  of  the  body,  whilst  Vesper- 


tilio  noctula  offers  the  shortest  proportional 
length  of  the  canal,  it  being  only  twice  as  long 
as  the  body.  The  latter  is  also  wholly  devoid 
of  a  ccecum. 

The  organs  of  generation. — The  male  organs 
of  the  Bats  bear  a  near  relation  to  those  of  the 
Quadrumana  and  of  Man,  in  some  striking 
respects.  The  penis  is  pendulous,  and  the 
proportions  between  the  different  organs  are 
not  very  dissimilar;  but  the  testes  do  not 
descend  from  the  abdomen  excepting  during  the 
breeding  season,  when  they  are  found  on  each 
side  of  the  anus,  whilst  the  large  epididymis  is 
seen  just  behind  them,  on  each  side  of  the 
origin  of  the  tail.  The  vesicula  seminales  are 
of  moderate  size,  and  consist  of  two  round 
white  sacs,  which  are  perfectly  simple,  form- 
ing each  a  single  cavity  with  a  secreting  in- 
ternal surface.  They  have  a  prostate  gland, 
which  surrounds  the  whole  circumference  of 
the  urethra,  and  appears  to  be  composed  of 
numerous  small  lobes.  They  have  also  Cow- 
per's  glands.  The  penis  is  very  similar  to  that 
of  the  other  more  highly  organized  forms,  the 
Quadrumana  and  Man.  It  is  of  moderate 
size,  pendulous,  and  supported  by  ligaments, 
as  in  the  other  cases.  There  is  a  small  bone 
of  the  penis.  The  muscular  portion  of  the 
urethra  is  rather  long.  The  glans  is  in  some 
species  enlarged  by  a  small  process  or  button 
on  each  side ;  the  urethra  opens  at  the  extreme 
point. 

The  female  organs  offer  nothing  very  par- 
ticular. The  vulva  is  round,  and  exhibits  a 
slight  appearance  of  a  clitoris  near  its  edge ; 
the  mouth  of  the  uterus  stands  out  into  the 
vagina.  The  uterus  is  two-horned  and  the 
horns  are  very  short. 

There  are  but  two  teats,  which  are  placed 
on  the  breast.  The  additional  ones  said  to 
exist  in  the  groin  of  the  Rhinolophi  are  most 
probably  ordinary  cutaneous  glands,  as  Kuhl 
could  discover  no  trace  of  mammary  glands 
beneath  them.  They  were  first  discovered  by 
Montagu  in  this  country,  and  by  Geoffrey  in 
France. 

The  Bats  are  among  those  animals  in  whom 
we  notice  the  remarkable  phenomenon  of  Hy- 
bernation,  of  which  it  is  unnecessary  to  say 
any  thing  here,  as  a  distinct  article  is  devoted 
to  the  subject.  (See  HYBERNATION.) 

For  the  Bibliography  see  that  of  MAMMALIA. 
(T.  Bell.) 

CHYLIFEROUS  SYSTEM  (in  Compa- 
rative Anatomy)  is  that  portion  of  the  vascular 
system  of  vertebrated  animals  which  is  destined 
to  convey  the  nutritious  part  of  the  food,  or  the 
chyle,  from  the  alimentary  canal  into  the  san- 
guiferous  vessels.  The  function  of  these  chy- 
liferous  vessels  appears  to  be  performed  by  the 
veins  in  the  invertebrated  classes,  where  the 
white  colour  of  the  blood  causes  them  to  re- 
semble more  closely  the  lacteals  or  chyliferous 
vessels  of  vertebrata.  Several  parts,  however, 
of  the  invertebrated  animals  have  been  taken 
by  anatomists  for  this  lacteal  system,  as  the 


CHYLIFEROUS  SYSTEM. 


601 


nervous  system  of  Molluscaby  Poll,  the  biliary 
tubuli  of  Insects  by  Sheldon,  the  mesenteric 
vessels  of  Echinodermata  by  Monro,  the  radi- 
ating prolongations  from  the  stomach  of  Me- 
dusae by  Carus.  The  chyle  of  vertebrata, 
derived  from  the  chyme  of  the  digestive  canal, 
and  much  resembling  the  white  blood  of  the 
lower  divisions  of  the  Animal  Kingdom,  varies 
in  its  physical  properties  and  chemical  com- 
position in  the  different  tribes  of  animals,  and 
in  the  same  animal  according  to  the  kind  of 
food  on  which  it  subsists,  (see  CHYLE,)  being 
most  allied  to  red  blood  in  the  highest  animals 
and  those  which  subsist  on  the  most  nutritious 
animal  food,  and  being  most  remote  from  that 
condition  in  the  lowest  fishes  and  the  most 
imperfect  animals.  The  vessels  which  con- 
vey, and  still  further  elaborate,  this  fluid,  the 
chyliferous  system,  like  the  other  systems  of 
the  body,  present  very  different  grades  of  de- 
velopment in  the  different  classes  of  vertebrata. 
In  fishes  they  consist  of  simple  vessels  in 
which  we  cannot  separate  the  two  usual  tunics; 
they  are  destitute  of  internal  valves  and  me- 
senteric glands,  they  form  two  strata  of  vessels 
between  the  coats  of  the  small  intestine,  and 
they  convey  a  limpid  chyle  to  the  receplaculum 
chyli,  from  which  it  is  sent  by  one  or  two 
thoracic  ducts  to  the  branches  of  the  su- 
perior cava  or  the  jugular  veins.  They  com- 
municate freely  with  the  veins,  they  already 
present  numerous  constrictions  as  rudimentary 
valves,  they  present  valvular  orifices  at  their 
entrances  into  the  veins,  and  their  numerous 
convoluted  plexuses  supply  the  place  of  me- 
senteric glands. 

The  chyliferous  vessels  are  nearly  in  the 
same  condition  of  development  in  the  amphi- 
bia, where  they  form  two  layers  on  the  parietes 
of  the  alimentary  canal,  are  destitute  of  con- 
globate glands,  form  plexuses  on  the  extended 
mesentery,  and  terminate  in  two  thoracic  ducts 
which  proceed  forwards  along  the  sides  of  the 
vertebral  column.  (See  AMPHIBIA.) 

In  the  class  of  reptiles  the  lacteals  pre- 
sent a  more  advanced  stage  of  formation, 
chiefly  in  the  development  of  the  internal 
valves  in  the  trunks  and  branches  in  all  these 
animals,  and  in  the  white  milky  condition  of 
their  contents  in  the  crocodilian  family.  (See 
REPTILIA.)  They  are  still  without  mesenteric 
glands,  their  valves  are  less  perfect  than  in 
birds  and  quadrupeds,  and  the  chyle  is  still 
limpid  and  colourless  in  the  serpents,  lizards, 
and  tortoises.  The  coarse  vegetable  food  of 
the  chelonia,  and  the  great  length  of  their  small 
intestine,  give  occasion  for  the  numerous  large 
chyliferous  vessels  which  cover  their  alimentary 
canal  and  mesentery.  The  place  of  mesenteric 
conglobate  glands  is  yet  supplied,  as  in  the 
inferior  vertebrata,  by  numerous  complicated 
networks  of  lacteal  vessels,  formed  in  different 
parts  of  their  course ;  and,  as  in  fishes,  two  or 
more  ducts  are  here  observed  passing  forwards 
from  a  single  wide  receptaculum.  The  tho- 
racic ducts  form  numerous  free  anastomoses 
with  each  other  in  their  course  forwards  to  the 
neck,  accompanying  the  left  branch  of  the 
aorta  to  the  anterior  part  of  the  trunk,  where 
VOL.  i. 


they  pour  their  contents  into  the  jugular  or 
subclavian  veins,  or  into  the  angle  between 
these  vessels.  Before  entering  the  veins  these 
ducts  receive  the  lymphatic  trunks,  as  in  other 
classes,  from  the  head  and  arms.  The  chyli- 
ferous vessels  of  the  chelonia  coming  from  the 
outer  and  inner  layers  spread  on  the  small  in- 
testine, unite  into  considerable  trunks,  which 
pass  along  the  mesentery  in  close  proximity  to 
the  bloodvessels.  The  thoracic  duct  of  the 
tortoise  surrounds  and  almost  conceals  the 
trunk  of  the  aorta  by  its  numerous  large  anas- 
tomosing branches. 

The  inferiority  of  the  chyliferous  system 
of  birds  to  that  of  quadrupeds  is  seen  even 
in  the  properties  of  the  chyle,  which  is  still, 
as  in  the  lower  tribes  of  vertebrata,  a  thin, 
colourless,  and  limpid  fluid.  The  lacteal  ves- 
sels are  now,  however,  more  obvious,  and 
more  regular  in  their  distribution,  and  are 
spread  in  more  crowded  layers  above  the  mu- 
cous and  above  the  muscular  coats  of  the  in- 
testine. They  collect  from  the  intestine  and 
form  numerous  anastomosing  plexuses  on  the 
mesentery,  in  place  of  the  conglobate  glands 
of  mammalia,  and  then  proceed,  with  the  lym- 
phatics, to  the  receptaculum,  which  sends  for- 
ward two  thoracic  ducts  to  terminate,  on  each 
side  of  the  neck,  at  the  junction  of  the  sub- 
clavian with  the  jugular  veins.  (See  AVES.) 
The  coats  of  the  lacteals  are  still  very  thin  and 
distensible  in  birds;  their  valves,  which  are 
more  abundant  on  the  trunks  and  branches 
than  in  reptiles,  are  still  so  incomplete  as  to 
allow  injections  to  pass  easily  against  their 
course,  and  although  conglobate  glands  are 
not  yet  developed  on  the  chyliferous  system, 
they  are  already  perceptible  on  the  lymphatics, 
especially  in  the  neck. 

The  chyliferous  system  of  the  mammalia, 
though  more  developed  than  that  of  all  the 
inferior  classes,  is  still  imperfect  as  a  hy- 
draulic apparatus  when  compared  with  the 
sanguiferous  system.  The  lacteal  and  lym- 
phatic systems  may  still  be  regarded  as  mere 
appendices  of  the  venous,  performing  the  func- 
tions which  are  assigned  to  veins  in  the  inver- 
tebrated  classes,  and  serving  as  inlets  to  the 
materials  which  renovate  the  blood.  No  pul- 
sating sacs  have  yet  been  detected  in  the  lym- 
phatic system  of  quadrupeds,  nor  any  distinct 
motion  in  the  lacteals,  the  receptaculum,  or 
the  thoracic  duct.  The  chyliferous  system  of 
this  class  presents  a  superiority  of  develop- 
ment in  the  almost  sanguineous  characters  of 
the  chyle,  in  the  more  perfect  structure  of  the 
vessels  and  their  valves,  in  the  development 
of  the  conglobate  mesenteric  glands,  in  the 
frequent  unity  or  concentration  of  the  thoracic 
duct,  and  in  the  more  isolated  condition  of  this 
system  from  the  sanguiferous.  The  mesenteric 
glands  are  chiefly  confined  to  the  mesentery  of 
the  small  intestine ;  they  are  generally  placed 
apart  from  each  other ;  sometimes  they  are 
united  into  a  pancreas  Asellii ;  they  are  firm  in 
texture,  highly  vascular,  and  composed  of  con- 
voluted lacteals,  like  more  concentrated  forms 
of  the  plexuses  of  the  lower  vertebrata. 

(R.  E.  Grant.) 
2  R 


I 


602 


CJCATRIX. 


CHYLIFEROUS  SYSTEM  (Human  Ana- 
tomy). See  LACTEAL. 

CICATRIX.  (Fr.  Cicatrice;  Germ.  Narbe.) 
When  from  accident  or  disease  a  portion  of 
any  organ  in  the  body  has  been  destroyed, 
a  process  is  set  up  by  Nature  for  the  repair 
of  the  breach,  a  new  structure  is  generated, 
which  possesses  many  properties  of  conside- 
rable interest  and  importance  both  in  a  phy- 
siological and  a  pathological  view.  The  new 
formation  constitutes  what  is  termed  a  cicatrix, 
and  the  process  by  which  it  is  completed,  the 
process  of  cicatrization.  We  shall  in  this 
article  give  a  general  view  both  of  the  mode  of 
of  repair  and  of  the  product  when  completed. 

The  restorative  process,  when  a  part  of  the 
skin  has  been  destroyed,  is  extremely  in- 
teresting. The  first  stage  varies  according 
as  the  part  is  removed  at  once,  as  by  exci- 
sion, or  secondarily,  as  by  sloughing.  The 
immediate  effect  of  removing  a  portion  of  skin 
is,  that  the  surrounding  integument,  by  its 
inherent  elasticity,  retracts,  arid  to  a  certain 
extent,  enlarges  the  breach  made  by  the  wound. 
In  a  short  time  after  the  infliction  of  the  injury 
inflammation  and  suppuration  take  place. 
As  the  next  step,  fibrine  is  effused,  which  very 
shortly  becoming  organized,  constitutes  those 
red,  soft,  roundish  elevations  known  by  the 
name  of  granulations.  As  these  form,  a  con- 
traction of  them  occurs,  by  which  the  edges 
of  the  sore,which  had  at  first  retracted,  are  now 
brought  back  again  towards  their  original  si- 
tuation. 

John  Hunter  informs  us  that  this  contracting 
tendency  in  the  granulations  is  in  some  degree 
proportioned  to  the  general  healing  disposition 
of  the  sore,  and  the  looseness  of  the  parts  on 
which  the  granulations  are  formed,  for  when 
there  is  not  a  tendency  to  skin,  the  granulations 
do  not  so  readily  contract.*  The  contraction 
continues  till  the  whole  is  healed  over,  but  its 
greatest  effect  is  at  the  beginning ;  one  cause 
of  which  is  that  the  resistance  to  it  from  the 
surrounding  parts  is  then  least. 

While  this  is  going  on  within  the  circum- 
ference of  the  sore,  and  immediately  pre- 
ceding the  commencement  of  actual  cicatri- 
zation, the  surrounding  old  skin,  close  to  the 
granulations,  becomes  smooth  and  rounded 
with  a  whitish  cast,  as  if  covered  with  some- 
thing white,  and  the  nearer  to  the  cicatrizing 
edge,  the  more  white  it  is.  At  this  moment 
the  process  of  cicatrization  is  actually  begin- 
ning, and  the  new  cuticle  may  now  be  ob- 
served to  be  spreading  from  the  circumference 
of  the  sore  towards  the  centre,  not  uniformly, 
but  creeping  irregularly  over  the  granulations, 
or  rather  formed  irregularly  from  them,  but 
always,  in  recent  sores,  spreading  in  a  con- 
tinuous surface  from  the  circumference.  In 
large  and  old  ulcers,  however,  in  which  the 
edges  of  the  surrounding  skin  have  but  little 
tendency  to  contract,  or  the  cellular  membrane 
underneath  to  yield,  the  old  skin  also  having 
but  little  disposition  to  skinning  in  itself,  the 

*  On  the  Blood,  8vo  edit. 


nearest  granulations  do  not  receive  from  it  a 
cicatrizing  tendency.  In  such  cases  new  skin 
forms  in  different  parts  of  the  ulcer,  standing 
upon  the  surface  of  the  granulations  like  little 
islands.  The  rapidity  with  which  the  skinning 
process  takes  place  in  this  stage  is  but  an  un- 
certain criterion  whereby  to  judge  of  the  time 
that  will  be  occupied  in  the  cure.  Generally 
speaking,  the  latter  stages  of  the  process  are 
much  slower  than  the  earlier,  particularly  when 
the  breach  of  surface  has  been  large. 

And  here  a  question  arises  :  is  the  new  skin 
that  is  formed  the  result  of  an  altered  state  of 
the  granulations  themselves,  or  is  it  an  entirely 
new  product  from  them  ?  Bichat  inclined  to 
the  former  opinion,  holding  that  the  granu- 
lations having  discharged  their  fluid  contents, 
collapsed,  and  uniting  one  to  another,  became 
converted  into  the  uniform  smooth  membrane 
in  question.  Hunter,  on  the  contrary,  con- 
sidered the  new  cutis  as  a  new  product,  the 
secretion  of  the  granulations.  Our  own  ob- 
servations lead  us  to  adopt  the  opinion  of 
Bichat.  It  seems  that,  as  soon  as  the  surface 
of  a  granulation  is  covered  over  with  epidermis, 
which  is  often  the  case  before  the  least  shrink- 
ing or  collapse  of  the  granulation  occurs,  then 
the  secreting  orifices  of  those  numerous  vessels 
of  the  granulation  which  had  hitherto  been 
pouring  out  pus  are  now  sealed  up,  and 
having  no  longer  any  use,  the  same  change 
takes  place  which  occurs  in  other  parts  of 
the  system  similarly  circumstanced :  an  or- 
gan no  longer  in  use  shrinks  and  the  fluid 
parts  become  absorbed,  and  the  elevated  soft 
and  spongy  granulations  shrink  into  the  thin 
and  somewhat  dense  fibrous  structure  of  the 
cicatrix.  We  cannot  agree  with  the  opinion 
of  M.  Dupuytren,  that  the  chorion  is  formed 
first,  and  the  epidermis  added  subsequently, 
since  we  have  often  detected  the  epidermis 
creeping  over  granulations  so  little  altered  in 
appearance  that  its  presence  could  only  be  dis- 
covered by  placing  the  part  in  such  a  light 
that  its  dry  shining  surface  could  be  distin- 
guished from  the  soft  villous  appearance  of  the 
neighbouring  granulations.  The  process  of 
contraction,  we  believe,  generally,  if  not  always, 
does  not  precede  but  follows  the  formation  of 
the  cuticle,  and  consequently  the  cutis  formed 
by  this  contraction  does  in  the  order  of  time 
follow  the  cuticle.  The  reason  of  this  we  can- 
not explain,  but  of  the  fact  we  cannot  doubt ; 
and  this  fact  accounts  for  the  very  slow 
formation  of  the  cuticle  in  the  first  healing 
of  an  ulcer  where  that  membrane  is  formed  from 
the  granulations.  The  organization  of  these 
bodies  may  be  said  to  be  much  inferior  to 
that  of  the  cutis  when  completed ;  hence,  when 
the  cuticle  of  a  cicatrix  is  abraded,  it  is  readily 
formed  again,  because  it  has  now  a  more  perfect 
organ  to  secrete  it. 

As  the  new  cuticle  covers  the  granulations, 
then,  these  two  striking  changes  immediately 
take  place  in  their  state ;  the  secretion  of  pus 
is  stopped,  the  surface  becoming  dry,  and  that 
process  of  shrinking  or  contraction  begins 
which  we  shall  find  to  continue  for  a  conside- 
rable period  after  the  whole  sore  is  apparently 


CICATRIX. 


603 


healed.  The  contractile  actfon  takes  place  in 
every  direction,  producing  that  depression  of 
the  cicatrix  which  is  observed  to  follow  the 
spreading  of  the  cuticle  over  the  granulations. 
Thus  those  parts  which  were  soft  and  spongy 
now  acquire  firmness,  and  form  a  condensed 
layer,  which  occupies  the  position,  and  per- 
forms some  of  the  functions  of  the  original 
cuds  which  had  been  destroyed. 

It  is  an  interesting  question,  why  the  cuticle 
in  covering  an  ulcer,  though  evidently  formed 
from  the  granulations,  is  arising  not  over  the 
whole  surface  of  the  ulcer  at  once,  as  it  is 
when  abraded  from  the  healthy  skin,  but  creeps 
from  the  circumference  towards  the  centre,  in 
a  slow,  progressive  manner  ?  It  seems  that  a 
greater  perfection  of  organization  is  necessary 
for  the  production  of  cuticle  than  for  the  for- 
mation of  granulations  capable  of  secreting 
pus.  If  we  examine  the  vascular  structure  of 
these  newly  formed  parts,  we  find  that  the 
bloodvessels  apparent  on  the  granulations  are 
few  and  very  irregular  in  their  course,  and 
often  in  figure  also,  having  an  appearance  re- 
sembling a  varicose  or  unequally  dilated  state ; 
this  we  take  to  be  an  indication  of  a  feeble 
and  incomplete  state  of  organization.  On  the 
contrary,  the  vessels  in  the  immediate  vicinity 
of  the  new  skin,  are  more  regular  in  form  and 
direction,  and  may  often  be  seen  running  on- 
wards through  the  neighbouring  granulations 
towards  the  centre  of  the  sore,  having  a  good 
deal  the  appearance  of  the  vessels  of  the  in- 
flamed cornea ;  and  where  this  is  not  remark- 
ably apparent,  the  granulations  in  the  imme- 
diate neighbourhood  of  the  parts  in  which  the 
skinning  process  is  going  on  are  more  vascular 
than  the  internal  ones.  Our  observations 
would  lead  us  to  believe  that  this  more  perfect 
system  of  circulation  commences  by  an  anasto- 
mosis newly  set  up  from  the  vessels  of  the 
edge  of  the  healthy  skin  first,  and  by  the  action 
of  these  newly  formed  vessels  the  cuticle  is 
secreted.  From  these,  others  are  still  sent  on 
over  the  surface  of  the  sore,  or  immediately 
under  it,  and  thus  by  progressive  steps  the 
necessary  degree  of  perfection  of  structure  is 
acquired,  and  is  immediately  followed  in  its 
progress  by  the  development  of  the  cuticle. 
This,  be  it  remembered,  is  still  a  different  state 
of  the  granulations  from  the  contracted  un- 
secreting  layer  which  "constitutes  the  new  cho- 
rion.  If  this  description  of  the  process  is 
consistent  with  Nature,  it  is  reasonable  to  sup- 
pose that  the  new  vessels  shooting  from  the 
edges  of  the  healthy  skin  would  be  more  per- 
fect, and  more  equal  to  the  task  required  than 
those  which  would  pass  through  the  granu- 
lations from  the  subjacent  cellular  tissue ;  and 
in  the  same  way  we  may  suppose  that  one  part 
being  in  the  before-mentioned  manner  com- 
pleted, is  better  fitted  to  send  on  new  vessels 
for  the  organization  of  the  next  portion  of 
granulations  than  the  granulations  themselves. 
It  is  moreover  to  be  expected  that  the  power 
of  organizing  its  neighbouring  parts  must  be 
superior  in  the  healthy  skin  to  that  of  any 
newly  formed  structure,  and  that  this  power 
will  in  an  extensive  sore  gradually  diminish 


as  the  distance  from  the  healthy  parts  in- 
creases ;  and  this  accords  with  the  well-known 
fact  that  the  cicatrization  goes  on  much  more 
slowly  in  the  latter  stages  of  healing  than  at 
the  commencement. 

Thus  the  external  process  of  skinning  is 
completed,  but  the  internal  changes  are  not 
yet  finished.  A  slow  but  remarkable  change 
is  going  on  for  a  considerable  time  longer,  by 
which  the  appearance  and  structure  of  the 
cicatrix  becomes  modified.  From  a  red  colour 
it  becomes  gradually  paler,  till  it  is  almost 
white ;  this  at  least  is  the  general  rule,  though 
under  circumstances,  to  be  presently  mentioned, 
the  result  is  different.  The  cicatrix  also  conti- 
nues to  contract  in  all  its  dimensions,  thus  not 
only  diminishing  in  extent,  but  sinking  below 
the  level  of  the  surrounding  skin,  and  becoming 
more  dense  and  thin  and  more  perfect  in  its 
organization,  till  it  has  assumed  the  appearance 
and  character  which  it  will  retain  through  the 
rest  of  life. 

It  is  this  power  of  contraction  resident  in  the 
new  chorion  of  the  cicatrix,  that  produces 
those  bridles  which  are  such  frequent  causes  of 
deformity  after  the  healing  of  extensive  burns. 
In  these  cases  there  does  not  seem  any  neces- 
sity to  have  recourse  to  any  peculiarity  of 
hypothesis  in  explaining  the  great  degree  of 
shrinking  that  so  commonly  occurs.  On  the 
contrary,  we  conceive  that  the  phenomena  at- 
tending the  healing  up  of  burns  are  to  be  ac- 
counted for  by  means  of  the  usually  recognized 
causes  of  the  shrinking  in  the  cicatrices  of 
wounds  in  general. 

We  have  now  described  the  process  of  re- 
pair in  wounds  in  the  skin,  with  loss  of  the 
entire  substance  of  the  cutis.  When  the  de- 
struction has  been  more  superficial,  the  process 
of  restoration  is  more  rapid,  and  the  result 
more  perfect,  inasmuch  as  the  part  upon  which 
the  burden  of  repair  devolves,  is  the  inner 
layers  of  the  original  cutis,  a  part  much  more 
highly  organized  and  more  equal  to  the  task 
than  the  cellular  tissue.*  In  wounds  which 
are  united  by  the  first  intention,  the  stage  of 
suppuration  does  not  take  place.  The  sub- 
stance which  would  have  formed  suppurating 
granulations  here  becomes  an  immediate  means 
of  union,  and  the  only  portion  of  new  skin 
formed  is  in  the  mere  line  where  the  divided 
edges  met,  a  line  always  visible  by  the  white 
colour  before  mentioned. 

In  the  healing  of  ulcers  in  any  of  the  mucous 
membranes,  the  process  would  appear  to  go  on 
much  in  the  same  way  as  on  the  skin.  Granu- 
lations shoot  up  from  the  bottom  of  the  ulcer; 
the  surrounding  healthy  membrane  is  drawn 
inwards  by  their  contractile  power,  and  the 
edges  of  the  ulcer  are  turned  in  and  become 
continuous  with  the  new  membrane,  which  at 
length  covers  the  ulcer.  When  the  destructive 
process  has  merely  gone  through  the  mucous 
membrane,  the  granulations  shoot  from  the  mus- 
cular coat,  and  the  contraction  is  of  course  ex- 
ercised only  upon  the  surrounding  mucous  coat; 
but  when  the  muscular  tunic  is  destroyed,  the 

*  See  Hunter  on  the  Blood,  8vo  edit.  p.  274. 
2  R  2 


604 


CICATRIX. 


granulations  grow  from  the  bottom  of  the  wound, 
that  is,  from  the  cellular  tissue  in  contact  with 
the  peritoneum ;  but  the  contraction  of  the  sur- 
rounding parts  now  diminishes  the  circumfe- 
rence of  the  ulcer  very  considerably  by  puck- 
ering up  this  thin  layer  of  membrane,  so  as  to 
give  it  externally  an  appearance  as  if  a  small 
portion  of  the  intestine  had  been  taken  up  by 
the  forceps  and  tied  with  a  ligature  on  the  in- 
side.* When  the  process  of  repair  is  com- 
pleted, a  fine  web-like  production  from  the 
edges  of  the  ulcer  overspreads  its  base,  and 
forms  fine  wrinkles  converging  towards  its 
centre.  This  production  is  destitute  of  villi, 
and  slightly  depressed.  When  the  ravages  of 
the  disease  have  been  very  extensive,  the  cica- 
trix  is  covered  by  puckered  cellular  tissue, 
formed  of  white  thread-like  filaments,  crossing 
each  other  in  all  directions,  and  leaving  pitted 
interstices.-)-  When  the  ulcer  was  small,  the 
cicatrix  has  sometimes  a  considerable  resem- 
blance to  the  scar  of  small-pox.J 

That  cicatrization  takes  place  in  the  lungs 
after  tuberculous  excavations,  the  observations 
of  Laennec§  and  Andral||  among  others,  have 
put  beyond  a  doubt ;  and  since  these  patholo- 
gists  have  made  public  their  observations  of 
the  fact,  and  pointed  out  the  signs  by  which  it 
may  be  known,  most  observers  have  borne  tes- 
timony to  the  accuracy  of  their  statements. 
According  to  Laennec  there  are  three  ways  by 
which  this  desirable  object  is  accomplished ; 
one,  by  the  walls  of  the  cavity  becoming  lined 
with  a  membrane  of  a  semicartilaginous  struc- 
ture and  smooth  polished  surface,  which 
seems  often  continuous  with  the  lining  mem- 
brane of  those  bronchial  ramifications  which 
open  abruptly  into  the  cavity.  This  state  of 
the  restorative  process  constitutes  a  sort  of  in- 
ternal cicatrix,  analogous  to  a  fistula,  and  is  in 
many  cases  not  more  injurious  to  health  than 
the  species  of  morbid  affection  just  mentioned. 
The  second  mode  of  cicatrization  consists  in 
the  obliteration  of  the  morbid  cavity  by  adhe- 
sion of  its  sides.  In  the  complete  state  they 
exhibit,  when  cut  into,  a  band  of  condensed  cel- 
lular substance  or  of  fibre-cartilaginous  struc- 
ture. The  bronchial  tubes  which  run  towards 
this  structure  are  obliterated  as  they  reach  it, 
and  there  is  generally  an  unusual  quantity  of 
the  peculiar  black  matter  of  the  lungs  in  the 
parts  bordering  upon  the  cicatrix ;  and  where 
this  is  the  case,  the  structure  of  the  lungs  is 
more  flabby  and  less  crepitous  than  natural. 
These  internal  cicatrizations  are  indicated  on 
the  surface  of  the  lung  by  a  depression  of  the 
pleura,  the  depth  of  which  corresponds  with 

*  Dr.  Latham  on  the  Disease  of  the  General 
Penitentiary,  p.  51. 

t  Dr.  Hope's  illustrations  of  Morbid  Anatomy, 
vol.  i.  p.  '203.  See  also  Billard's  Recherches 
d'Anat.  Pathol.  p.  534. 

f  Bright's  Medical  Reports,  vol.  i.  p.  182,  where 
are  some  very  interesting  illustrations  of  this  por- 
tion of  pathological  anatomy.  See  also  on  this 
subject  a  valuable  paper  by  M.  Troillet  in  the  Jour- 
nal Gen.  de  Medecine.  Reported  in  the  Med.  Chir. 
Rev.  vol.  v.  p.  192. 

§  On  Mediate  Auscultation,  translation  by  Dr. 
Forbes,  2d  edit.  p.  300. 

|]  Clinique  Medicale,  torn.  iii.  p.  382. 


the  size  of  the  previous  excavation,  and  is 
sometimes  so  deep  as  to  form  a  large  over- 
lapping prominence  of  the  neighbouring  sound 
parts.  Here  we  have  another  instance  of  the 
same  contractile  tendency  in  newly  formed 
structures,  which  is  so  striking  in  cicatrizations 
of  the  skin;  a  tendency  resulting  from  the  gene- 
ral law  by  which  the  labour  of  restoration  is,  as 
much  as  possible, spared  to  the  animal  system. 

The  third  species  of  cicatrix  in  the  lungs  is 
that  formed  by  the  fibro-cartilaginous  walls  in- 
creasing in  thickness  till  they  fill  up  the  cavity, 
thus  leaving  a  blueish  or  greyish  white  mass,  in 
which  large  bronchi  terminate  abruptly  as  in 
the  preceding  case.  Cicatrices  of  the  two  last 
kinds  are  not  uncommon.* 

In  the  healing  of  common  abscesses,  whether 
in  the  subcutaneous  cellular  tissue  or  in  the 
more  deep-seated  parts,  the  mode  of  cicatriza- 
tion is  much  the  same  as  in  the  second  species 
just  described.  As  the  fluid  contents  are  re- 
moved by  evacuation,  the  cavity  of  the  abscess 
is  diminished  in  extent  partly  by  the  contrac- 
tion of  the  surrounding  tissue  and  partly  by  the 
granulations  arising  from  the  sides  of  the  ca- 
vity, and  as  the  opposite  sides  are  thus  brought 
in  contact  they  adhere,  and  at  length  leave  a 
fibrous  cicatrix,  whitish  and  more  dense  than 
the  surrounding  cellular  tissue.  It  is  remark- 
able that  few  or  no  abscesses  granulate  till  they 
are  exposed,  and  that  after  they  are  opened 
there  is  one  surface  that  is  more  disposed  to 
granulate  than  the  others,  which  is  the  surface 
next  the  centre  of  the  body  in  which  the  sup- 
puration took  place.  The  surface  next  the 
skin  hardly  ever  granulates,  but  on  the  contrary 
has  an  ulcerative  tendency.  The  proximate 
cause  of  this  remarkable  difference  is  not  evi- 
dent, but  the  utility  of  it  in  the  healing  of  the 
abscess  is  clear  and  striking.f 

We  have  now  considered  the  processes  by 
which  nature  repairs  the  breach  in  the  healthy 
structure ;  let  us  in  conclusion  shortly  examine 
the  characters  which  mark  the  cicatrix  when 
completed.  This  new  formation,  though  in 
many  points  it  resembles  and  fulfils  the  func- 
tions of  the  old  and  perfect  skin,  yet  differs 
from  it  in  many  material  respects. 

1 .  It  occupies,  as  we  have  stated,  a  smaller 
space,  having  by  its  contraction  drawn  the 
surrounding  skin  inwards,  and  thus,  by  the 
wise  economy  of  nature,  diminished  the  surface 
requiring  new  skin  to  cover  it.  This  is  of  course 
most  strikingly  seen  in  those  parts  where  the 
cellular  texture  is  loose  and  yielding,  as  in  the 
scrotum,  where  a  large  loss  of  skin  is  often 
healed  with  only  a  very  small  cicatrix.  On  the 
contrary,  parts  that  cannot  so  yield  are  healed 
with  a  proportionately  large  cicatrix,  as  in 
wounds  of  the  scalp,  &c.  2.  The  texture  of 
the  cicatrix  is  frequently  harder  and  thicker 
than  the  natural  skin.  This  circumstance  varies 
considerably,  but  we  believe  this  variation  will 
be  found  to  bear  a  pretty  exact  relation  to  the 
degree  of  contraction,  to  the  length  of  time 
occupied  in  the  cure,  and  to  the  irritation  to 

*  See  Hope's  Illustrations  of  Morbid  Anatomy, 
vol.  i.  p.  34. 

t  Hunter  on  the  Blood,  p.  593. 


CICATRIX. 


605 


which  the  ulcer  was  subjected  in  the  process  of 
healing.  When  these  have  been  considerable, 
the  hardness  is  correspondingly  great,  while,  if 
the  cure  has  been  expeditious  and  the  part 
been  kept  extended  and  irritation  avoided,  the 
cicatrix  remains  soft,  thin,  and  pliable,  a  point 
of  great  importance  in  practice  as  applied  to 
the  healing  of  burns.  3.  The  colour  of  the 
new  skin  is  different  from  the  natural  parts. 
This  arises  from  the  want  of  rete  mucosum, 
which  is  not  regenerated  till  long  after  the 
other  tissues,  and  sometimes  not  at  all.  For 
this  reason  a  cicatrix  in  a  Black  is  as  white  as 
that  in  an  European ;  but  after  a  considerable 
lapse  of  time,  this  structure  is  sometimes 
formed  anew,  and  in  some  instances  becomes 
even  of  a  darker  colour  than  before.  4.  The 
surface  is  perfectly  dry  from  the  want  of  ex- 
halent  pores,  which  are  never  found  to  be 
restored  even  in  the  oldest  cicatrices.  Indeed, 
in  cases  where  the  chorion  has  not  been  de- 
stroyed through  its  entire  thickness,  the  loss 
of  substance  reaching  only  through  its  outer 
layers,  these  pores  are  generally  obliterated, 
and  the  important  exhalent  function  of  the 
skin  is  annihilated;  and  even  when  the  injury 
has  extended  only  through  the  external  vas- 
cular structure  of  the  skin,  as  is  the  case  in  the 
healing  of  a  blister  which  has  been  long  in- 
flamed, we  have  observed  a  drier  state  of  the 
parts,  and  more  polished  than  the  surrounding 
skin  which  had  not  been  injured.  From  this  pe- 
culiarity in  the  cicatrix,  when  the  whole  body  is 
bathed  in  sweat  these  parts  are  dry  and  po- 
lished. This  state  of  dryness,  however,  partly 
results  from  another  anatomical  deficiency, 
namely,  of  the  perspiratory  glands,  which  are 
destroyed  in  cases  where  the  entire  integument 
has  been  injured,  and  these  are  of  course  never 
regenerated.  5.  The  new  tissue  contains  no 
hairs,  and  if,  after  superficial  wounds,  a  few 
scattered  hairs  appear  on  the  surface,  they  are 
feeble  and  white.  6.  After  the  healing  of  a 
large  ulcer  of  long  standing,  the  new  surface 
is  sometimes  much  lower  than  the  surround- 
ing skin.  Nature  seems,  in  these  cases,  to 
have  exhausted  her  energies  in  the  long  en- 
deavour to  heal  the  ulcer,  and  the  granulations 
never  rise  to  the  level  of  the  surrounding  skin, 
as  in  recent  cases.  The  new  cuticle  there- 
fore commences  upon  those  granulations  which 
shoot  from  the  elevated  edges  of  the  ulcer,  and 
the  cicatrizing  process  is  thus  led  as  it  were 
into  the  hollow  of  the  ulcer,  and  spreads  along 
its  surface,  completing  the  cicatrix  in  an  exca- 
vated form.  7.  The  elasticity  of  the  cellular 
tissue  under  the  new  chorion  is  less  than  that 
of  the  ordinary  cellular  web;  nor  does  it  allow 
of  distension  to  the  same  degree.  This  is 
seen  in  oedema  and  emphysema,  where  this 
part  will  often  remain  depressed  while  the  sur- 
rounding parts  are  raised  and  distended ;  it  is 
also  seen  in  the  impediments  which  large  cica- 
trices prove  to  the  movements  of  the  joints. 
The  same  circumstance  perhaps  also  gives  a 
reason  for  there  being  no  fat  contained  in  these 
parts.  This  want  of  extensibility  seems  to  be 
but  one  consequence  of  the  law  which  regu- 
lates the  products  of  inflammatory  action.  The 
clastic  power  is  materially  diminished  in  the 


natural  cellular  tissue  by  inflammation,  a  de~ 
gree  of  stiffness  and  difficulty  of  movemen* 
remaining  for  a  long  time  after ;  and  as  the 
tissue  of  a  cicatrix  is,  ab  initio,  the  product  of 
inflammatory  action,  it  is  to  be  expected  that  it 
should  shew  the  same  effects. 

How  far  are  the  vascular  and  nervous  func- 
tions of  the  lost  part  restored  in  the  cicatrix  ? 
It  is  probable  that  the  new  structure  receives 
nerves,  but  in  small  number.  Of  those  senses 
which  can  be  implicated  in  the  destructive 
process  of  ulceration,  that  of  touch  alone  seems 
to  be  restored.  This  is  so  in  a  marked  though 
still  imperfect  degree,  the  sensation  in  these 
parts  being  somewhat  of  that  dull  kind  expe- 
rienced after  paralysis. 

On  the  temperature  of  the  cicatrix  we  have 
not  made  sufficient  observations  to  generalize, 
but  we  have  found  that  the  actual  temperature 
of  the  bridle  from  a  burn,  while  it  retains  its 
hardness,  is  several  degrees  above  that  of  the 
healthy  skin,  while  the  power  of  retaining  its 
temperature,  or  of  resisting  the  extremes  of 
heat  and  cold,  is  much  inferior  in  the  cicatrix  to 
that  which  the  healthy  skin  possesses,  although 
the  actual  temperature,  under  ordinary  circum- 
stances, is  the  same  as  the  surrounding  skin. 
Almost  every  traveller  to  the  Poles  or  to  the 
Tropics  mentions  the  liability  of  old  ulcers  that 
had  been  healed,  to  announce  the  extremes  of 
temperature  by  pain  and  inflammation. 

The  bloodvessels  of  the  new  structure  are  at 
first  numerous,  as  indicated  by  the  redness  and 
the  readiness  with  which  it  bleeds,  but  after- 
wards they  diminish  much  in  size  and  number, 
so  that,  in  an  old  cicatrix,  it  is  often  impos- 
sible to  force  an  injection  into  them.  M.  Du- 
puytren  tells  us  that  in  scars  upon  the  face  the 
greatest  heat  from  exercise,  or  the  influence  of 
the  mind  in  producing  blushing,  leaves  this 
part  uncoloured  amid  the  surrounding  redness.* 
Bichat  assures  us  that  even  the  new  epidermis 
itself  is  overrun  with  bloodvessels.f  We  have 
certainly  never  been  able  to  discover  the  least 
trace  of  vascularity  in  it,  nor  have  we  found 
that  sensibility  in  this  part  which  he  describes. 
It  seems  to  be  a  matter  of  doubt  at  present  how 
far  the  function  of  secretion  exists  in  the  new 
production.  Dr.  Bright  seems  to  believe  in  its 
restoration,  since  he  says  that  the  scar  in  one  of 
his  observations  appeared  to  be  covered  with  a 
true  mucous  membrane ;  but  it  is  right  to  state 
that  the  proof  he  gives  of  this  is  rather  equi- 
vocal, namely,  that  the  surface  was  quite  con- 
tinuous with  the  membrane  lining  the  rest  of 
the  canal ;  "  indeed,"  he  adds,  "  when  inspect- 
ing the  ulcer  in  the  process  of  healing,  we  per- 
ceive the  vessels  of  the  mucous  membrane 
running  over  the  surface  to  be  repaired."}:  M. 
Troillet  mentions  in  round  terms  that  the  cica- 
trix had  the  thickness,  consistence,  and  ap- 
pearance of  mucous  membrane  ;§  but  neither 
he  nor  Dr.  Bright  says  any  thing  in  particular 
as  to  the  villous  structure,  which  we  conceive  to 
be  an  essential  characteristic  of  some  forms  of 


*  Le9ons  de  Clinique  Chir.  torn.  ii.  p.  47. 
t  General  Anatomy,  Transl.  vol.  ii.  p.  899. 
J  Mcd.  Reports,  vol.  i.  p."  182. 
§  Med.  Chir.  Rev.  vol.  v.  P.  194.      . 


606 


CILIA. 


raucous  membranes.*  Dr.  Hope's  and  M.  Bil- 
lard's  cases  were  destitute  of  villi,  and  the 
latter  expresses  a  doubt  whether  it  ever  takes 
place.  Our  own  observations  decidedly  incline 
us  to  the  same  opinion. 

Like  all  adventitious  organic  products,  cica- 
trices are  very  readily  irritated  and  are  de- 
stroyed by  ulceration  with  amazing  rapidity. 
A  few  days  and  even  a  few  hours  are  sometimes 
sufficient  to  undo  the  restorative  labours  of 
many  months;  but  this  destruction  is  often  su- 
perficial, and  then  the  after-healing  is  as  rapid 
as  the  previous  ulceration. 

M.  Dupuytrenf  informs  us  that  the  cicatrix 
resulting  from  an  entire  destruction  of  the  skin 
is  not  liable  to  be  affected  by  many  exanthe- 
matous  diseases,  such  as  scarlet  fever,  measles, 
and  small-pox;  it  remains  pale  in  the  midst  of 
the  inflammation  and  eruption  which  covers 
the  neighbouring  parts.  The  contrary  takes 
place  only  in  superficial  cicatrices,  under  which 
some  layers  of  the  original  cutis  exist,  and 
which  participate  in  the  properties  as  well  as 
in  the  inflammatory  tendencies  of  the  rest  of 
the  skin. 

In  conclusion  we  may  state,  that  it  appears, 
from  the  previous  considerations,  that  in  the 
repairing  of  the  injuries  in  question,  beautiful 
as  is  the  process  and  useful  as  are  the  results, 
yet  nature's  great  object  does  not  consist  so 
much  in  an  endeavour  to  restore  the  lost  struc- 
ture in  all  its  functions  and  perfections  of 
organization,  as  merely  to  produce  a  covering 
for  those  parts  which  remain  uninjured,  to  act 
as  a  defence  to  them  from  external  irritations 
and  injuries,  and  possessed  therefore  only  of 
such  a  degree  of  vitality  and  of  such  properties 
of  structure  as  shall  be  sufficient  for  its  own 
preservation  and  repair. 

(A.  T.  S.  Dodd.) 

CILIA,J  (in  anatomy,  Fr.  Cils;  Germ. 
Wimperhaare.)  This  term  is  used  to  desig- 
nate a  peculiar  sort  of  moving  organs,  re- 
sembling small  hairs,  which  are  visible  with 
the  microscope  in  many  animals.  These  organs 
are  found  on  parts  of  the  body  which  are 
habitually  in  contact  with  water  or  other  more 
or  less  fluid  matters,  and  produce  motion  in 
these  fluids,  impelling  them  along  the  surface 
of  the  parts.  The  currents  or  other  motions 
thus  produced  serve  various  purposes  in  the 
economy  of  the  animals  in  which  they  occur. 
In  other  circumstances  the  cilia  serve  as 
organs  of  locomotion,  some  aquatic  animals 
propelling  themselves  through  the  water  by 
their  means. 

Cilia  have  now  been  ascertained  to  exist  in 
a  great  many  invertebrated  and  in  all  verte- 
brated  animals,  except  Fishes  ;§  having  been 
very  recently  discovered  by  Purkinje  and  Va- 
lentin on  the  respiratory  and  uterine  mucous 
membranes  of  Mammalia,  Birds,  and  Reptiles. 

The  terms  "  vibratory  motion  "  and  "  ciliary 
motion"  have  been  employed  to  express  the 

*  Med.  Chir.  Rev.  vol.  x.  p.  324. 

t  Op.  cit.  tome  ii.  p.  48. 

i  For  another  signification  of  this  term,  see  the 
articles  EYE  and  LACHRYMAL  APPARATUS. 

§  Fishes  are  no  longer  an  exception :  see  note' 
at  page  632. 


appearance  produced  by  the  moving  cilia; 
the  latter  is  here  preferred,  but  it  is  used  to 
express  the  whole  phenomenon  as  well  as  the 
mere  motion  of  the  cilia. 

A  considerable  space  has  been  allotted  to 
the  present  article,  more  perhaps  than  its  re- 
lative importance  may  seem  to  demand,  chiefly 
for  the  reason  that,  with  one  exception,  no 
attempt  has  been  hitherto  made  to  collect  and 
describe  under  appropriate  heads,  the  facts 
known  on  the  subject.  The  exception  alluded 
to  is  a  work  by  Purkinje  and  Valentin,*  which 
appeared  while  this  article  was  in  progress,  and 
which  contains  not  only  an  account  of  their  own 
discovery,  but  a  history  of  all  preceding  obser- 
vations. But  the  manner  of  treating  the  sub- 
ject in  the  work  alluded  to  is  for  the  most  part 
so  different  from  that  which  is  here  followed, 
that  its  publication  has  not  seemed  to  warrant 
any  material  abridgement  of  the  following 
article,  which,  on  the  contrary,  it  has  increased 
by  affording  much  new  and  important  matter, 
as  will  be  acknowledged  in  its  proper  place. 
Another  ground  on  which  indulgence  may  be 
claimed  for  details  which  are,  perhaps,  greater 
than  may  seem  commensurate  with  the  impor- 
tance of  the  subject,  is  that  many  of  the  facts 
are  here  described  for  the  first  time,  and  it  was 
felt  desirable  to  state  them  in  their  full  extent, 
which  could  not  be  done  intelligibly  without 
considerable  length  of  description. 

The  article  is  divided  into  two  parts  ;  the 
first  comprehends  the  particular  facts,  or  an 
account  of  the  phenomena  as  they  occur  in  the 
different  tribes  of  animals  considered  in  Zoo- 
logical order,  with  the  history  of  their  dis- 
covery; the  second  part  consists  of  general 
deductions  from  the  first,  and  also  treats  of  the 
structure  and  mode  of  action  of  the  cilia  in 
general.  This  method  has  been  adopted  as 
appearing  on  the  whole  best  suited  to  the  pre- 
sent state  of  knowledge  on  the  subject. 

PART    I. 

1.  Infusoria. —  Cilia  exist  very  extensively 
in  the  different  tribes  of  Infusory  Animalcules ; 
indeed  they  constitute  the  principal  organs  of 
motion  in  these  small  animals.  When  a  drop 
of  water  containing  Infusoria  is  brought  under 
the  microscope,  these  creatures  are  seen  swim- 
ming rapidly  through  it  in  various  directions ; 
and  as  they  move  along,  small  particles  of 
foreign  matter  which  happen  to  lie  near  their 
path  are  thrown  into  agitation,  obviously  in- 
dicating the  existence  of  currents  in  the  neigh- 
bouring water.  When  the  animals  remain 
steady  in  one  place,  these  currents  become 
much  more  distinct,  setting  in  particular  di- 
rections, and  causing  the  small  particles  to  run 
in  a  stream  to  and  from  the  animal.  If  the 
magnifying  power  be  sufficiently  strong,  small 
transparent  filaments  will  be  distinguished, 
projecting  from  the  surface  of  the  animalcules 
and  moving  in  a  very  rapid  manner.  These 
are  the  cilia ;  they  serve  like  fins  or  paddles 
to  carry  on  the  animal  in  its  progression  through 
the  water,  and  when  it  is  stationary,  they  impel 
the  water  in  a  current  along  the  surface,  which 

*  De  phenomeno  motus  vibratorii,  &c.  4to. 
Wratisl.  1835. 


CILIA. 


007 


is  beset  with  them.  They  may  be  often 
most  distinctly  seen  when  their  motion  be- 
comes languid  or  impeded,  as  is  the  case 
when  the  water  round  the  animal  is  diminished 
by  evaporation  to  such  a  degree  as  not  to  afford 
scope  for  their  full  and  rapid  play. 

The  cilia  of  the  Infusoria  in  their  arrange- 
ment are  either  separate  and  independent,  or 
combined,  forming  in  the  latter  case  the  rota- 
tory or  wheel-like  organs  of  the  rotiferous  tribes 
of  animalcules. 

In  the  first  or  simple  form,  which  exists  in 
the  Polygastric  Infusoria  (Jig.  289),  the  cilia 
are   usually    set    round  the 
mouth    or  spread  over  the          JVg.289. 
body    generally,     in    which 
case  they  are  often  disposed 
in  regular  rows.  Their  struc- 
ture has  been  carefully  in- 
vestigated by  ProfessorEhren- 
berg,  who  states  that  each  is 
furnished  with  a  bulb  at  the 
root,  to  which  minute  muscles 
are  attached.   A  slight  degree 
of  rotation  communicated  to 
the  bulb  causes  a  much  more 
extensive  motion  in  the  rest 
of  the  organ,  which  in  its  re-         Leucophryt 
volution    describes    a  cone.  patula. 

From  lime  to  time  the  animal  sets  its  cilia  in 
motion,  and  then,  if  its  body  be  free,  the  cilia, 
acting  like  fins  or  oars,  move  it  onwards  through 
the  water,  serving  in  this  case  as  organs  of  lo- 
comotion. If  the  body  is  fixed,  the  cilia  com- 
municate an  impulse  to  the  surrounding  water 
and  excite  a  current  in  it.  This  may  always 
be  made  evident  by  mixing  with  the  water 
some  colouring  matter,  the  particles  of  which 
are  hurried  along  by  the  current.  Many  of 
these  particles  are  conveyed  towards  the  mouth, 
where  some  are  swallowed  and  the  rest  thrown 
back,  the  cilia  in  this  case  serving  the  animal 
as  a  means  of  seizing  its  food. 

In  their  combined  form  the  cilia  constitute 
the  singular  and  well-known  rotatory  or  wheel- 
like  organs  of  the  Rotiferous  Infusoria.     These 
are  formed  of  one  or   more  circles  of  cilia, 
placed  on  the  fore  part  of  the  animal,  as  in 
Philodina  (fg.  290),  in   which  the  organ  is 
double,  consisting  of  two  cir- 
cles of  cilia  set  on  two  short      Fig.  290. 
processes,  one  on  each  side  of 
the   mouth.      This   apparatus 
can   be  retracted    or    pushed 
out  at  the   will  of   the  ani- 
mal.    When  in  motion,    the 
circles  of  cilia  have  the  ap- 
pearance   of   toothed    wheels 
turned   round   on  their  axes, 
first  in  one  direction  and  then 
in  the  opposite.    Various  ex- 
planations   of    this    apparent 
revolution  have  been    given. 
According  to  Ehrenberg  it  is         Philodina 
an    optical  deception,   which       erythropthalma. 
he  thus  explains  :    the   individual  cilia  com- 
posing the  rotatory  organ  move  in  the  same 
manner  as    the    separate    cilia    above    men- 
tioned, that   is,  they  each  revolve  in  such  a 


way  as  to  circumscribe  a  conical  space.  When 
viewed  sideways,  in  performing  this  revolution 
they  must  necessarily  pass  at  one  moment  a 
little  nearer,  at  another  a  little  more  distant 
from  the  eye,  or,  in  other  words,  become  alter- 
nately more  and  less  distinct  to  the  view  at 
short  intervals ;  and  this  alternation  occurring 
over  the  whole  circle  gives  rise  to  a  seeming 
change  of  place  in  every  part  of  it,  and  a  con- 
sequent appearance  of  rotation.  Perhaps  it 
would  be  an  equally  satisfactory  and  a  more 
simple  explanation  to  consider  the  appearance 
as  occasioned  by  an  undulatory  motion  of  the 
cilia,  such  as  that  produced  by  the  wind  in  a 
field  of  corn;  the  undulations  following  one 
another  in  every  part  of  the  circle  would  give 
the  appearance  of  rotation.  Such  a  waving 
motion  of  the  cilia  undoubtedly  occurs  in 
other  animals.  The  Rotifera  set  in  motion  or 
retract  their  ciliary  organs  apparently  by  a 
voluntary  act ;  they  use  them  for  similar  pur- 
poses as  other  Infusoria  use  their  simple  cilia ; 
when  the  body  is  free,  the  rotatory  organ  pro- 
pels it  through  the  water;  at  other  times  the 
animal  fixes  itself  by  its  tail,  and  setting  in 
motion  its  wheels,  produces  currents  in  the 
water,  by  means  of  which  it  seizes  its  food. 
These  currents  in  most  of  the  Rotifera  have  a 
determinate  and  regular  direction. 

The  cilia  of  the  Infusoria,  then,  serve  as 
organs  of  locomotion;  and  in  the  greater 
number  of  species  they  are  the  only  visible 
organs  for  this  purpose ;  indeed  it  is  not  im- 
probable that  they  may  exist  in  others  in 
which  from  their  smallness  they  have  hitherto 
eluded  observation ;  as  in  such  cases  cur- 
rents are  observed  which  are  most  probably 
produced  by  invisible  cilia.  Secondly,  the 
cilia  are  employed  by  the  animals  in  catching 
their  food.  Thirdly,  it  is  extremely  probable 
that,  by  bringing  successive  portions  of  water 
into  contact  with  the  surface  of  the  animal, 
they  serve  also  for  respiration. 

Soon  after  the  invention  of  the  microscope, 
the  animalcula  of  infusions  became  a  favourite 
subject  for  its  employment,  and  the  cilia  and 
the  motions  which  they  produced  did  not 
escape  the  notice  of  the  earlier  microscopic 
observers.  Leeuwenhoek  observed  them  dis- 
tinctly and  recognised  their  use,  and  probably 
he  was  the  first  that  did  so.  He  repeatedly 
makes  mention  of  them  in  his  writings.  At 
one  place*  he  describes  them  in  an  animalcule, 
which  seems  to  have  been  the  volvox,  as  short 
slender  organs  projecting  a  little  from  the  body, 
by  means  of  which  the  animal  produced  a  re- 
volving motion  and  moved  onwards.  A'gain,-f* 
in  speaking  of  the  animalcules  which  he  ob- 
tained from  an  infusion  of  pepper,  he  states 
that  these  animals  produced  a  great  commotion 
in  the  water  by  means  of  divers  organs  placed 
on  the  fore  part  of  the  head,  which  organs  also 
the  animals  used  in  swimming.  "  In  this 
way,"  says  he,  "  they  occasioned  such  a  cir- 
cular eddy  in  the  water  that  not  only  several 

*  Continuatio  Arcanorum  Naturae,  1719,  p.  382, 
Epist.  144. 

t  Continuatio  Epistolarum,  1715,  p.  95,  Epist. 
17,  Oct.  1687. 


608 


CILIA. 


small  bodies  floating  in  the  water  were  moved 
in  a  circular  manner,  but  even  many  very, 
minute  animalcules,  though  able  to  swim 
vigorously,  when  they  approached  the  larger 
animalcules,  were  whirled  about  for  some  time 
in  a  circular  manner."  In  announcing  his 
discovery  of  the  wheel  animal,*  he  describes 
its  rotatory  apparatus  as  two  projecting  discs 
set  round  with  very  slender  elongated  organs. 
"  Imagine,"  says  he,  "  two  wheels  set  round 
with  points  of  needles,  and  moved  very  swiftly 
round  from  west  by  the  south  to  the  east."  He 
adds  that  he  cannot  comprehend  how  such 
motion  takes  place  in  a  living  body.  Lastly, 
in  describing  a  small  animal  which  he  found 
adhering  to  the  water-lentil,  (probably  a  species 
of  vorticella,)  and  speaking  of  the  currents 
which  it  excites,  and  by  which  it  attracts  its 
food,  he  adds  the  following  reflection  :f  "  More- 
over it  is  necessary  that  these  animals,  and  in 
general  all  such  as  are  fixed  and  cannot  change 
their  place,  should  be  provided  with  an  appa- 
ratus for  stirring  up  motion  in  the  water,  by 
which  motion  they  obtain  any  matters  that  float 
in  the  water,  for  their  nourishment  and  growth 
and  for  covering  their  bodies." 

Baker,!  next  to  Leeuwenhoek,  takes  notice 
of  the  cilia  of  animalcules.  He  observed  them 
in  many  species,  and  named  them  fins,  or  feet, 
and  sometimes  fibrillae.  He  distinctly  recog- 
nised the  currents  produced  by  them,  and  in- 
ferred the  existence  of  cilia  as  the  cause  of 
visible  currents  in  cases  where  the  cilia  them- 
selves could  not  be  seen.§  In  particular,  he 
bestowed  much  pains  in  investigating  the  eco- 
nomy of  the  wheel  animal  previously  disco- 
vered by  Leeuwenhoek,  and  addressed  a  letter 
to  the  Royal  Society  on  the  subject,  in  1744.JJ 
He  there  describes  its  rotatory  apparatus  as 
"  a  couple  of  semicircular  instruments  round 
the  edges  of  which  many  little  fibrillae  move 
themselves  very  briskly,  sometimes  with  a  kind 
of  rotation,  and  sometimes  in  a  trembling  or 
vibrating  manner,"^ "  by  this  means  a  cur- 
rent of  water  is  brought  from  a  great  distance 
to  the  very  mouth  of  the  creature,  which  thereby 
is  supplied  with  many  little  animalcules  and  va- 
rious particles  of  matter."**  He  also  states  that  the 
wheels  are  instruments  of  locomotion  by  which 
the  creature  swims.ff  Baker  drew  a  distinc- 
tion between  the  rotatory  and  vibratory  motions 
of  the  cilia,  these  organs  being  moved  in  some 
animals  in  the  one  way,  in  some  in  the  other, 
while  in  others  they  seemed  capable  of  being 
used  in  both  ways.jj  It  appears  that  he  was 
aware  of  the  true  structure  of  the  so-called 
wheels,  and  though  he  often  speaks  of  their 

*  Continuatio  Arcanorum  Naturae,  1719.  p.  386, 
Epist.  144. 

t  Epistolae  Physiologicae,  1719,  p.  66.  Epist.  7. 

^  I  cite  his  work  entitled  "  Of  Microscopes, 
and  the  Discoveries  made  thereby,"  London,  1785, 
although  his  observations  were  previously  related 
in  separate  memoirs  of  a  much  earlier  date. 

S  Of  Microscopes,  vol.  i.  p.  71,  p.  80. 

\\  Reprinted  in  op.  cit.  ii.  p.  267. 

IF  P.  271. 

»*  P.  273. 

tt  P.  284. 

n  P.  292. 


being  turned  round,  he  was  still  doubtful  of 
the  reality  of  the  apparent  rotation. 

Spallanzani,  in  his  curious  and  interesting 
researches  on  the  production  and  economy  of 
the  Infusoria,  made  observations  similar  to  those 
of  Baker  on  the  cilia  and  their  motions.  He 
describes  them  as  small  filaments  or  points 
agitated  with  a  vibratory  or  oscillating  motion. 
He  conceived  them  to  be  organs  of  locomotion 
which  the  animals  used  in  swimming,*  and 
that  they  also  served  to  excite  a  vortex  or  cur- 
rent by  means  of  which  food  was  brought  to 
the  mouth.  "  The  oscillating  filaments  cause 
the  vortex;  the  vortex  draws  the  floating  par- 
ticles into  the  aperture  or  mouth  of  the  animal- 
cule, and  the  latter  chooses  for  its  aliment  the 
most  delicate,  or  at  least  those  which  suit  it 
best."f  He  afterwards  describes  the  ciliary 
apparatus  of  the  vorticella  in  a  similar  man- 
ner.;}: In  the  account  of  his  singular  experi- 
ments on  the  apparent  resuscitation  of  the 
Rotifer,  he  describes  its  wheel  organs  as  two 
circles  of  filaments,  exactly  like  the  vibrating 
filaments  of  other  Infusoria,  which  by  their 
continued  motion  give  rise  to  the  appearance 
of  two  moving  wheels ;  but  he  distinctly  states 
that  the  rotation  is  only  apparent,  not  real. 
These  organs,  he  adds,  serve  the  same  purposes 
as  the  simple  cilia.§ 

Needham,||  about  the  same  time  as  Spallan- 
zani, correctly  observed  the  cilia,  and  recog- 
nized their  uses.  Saussurelj  observed  the  cur- 
rents, but  did  not  perceive  the  cilia.  Pallas,** 
in  his  systematic  work  on  Zoophytes,  describes 
the  eddies  or  currents  produced  by  certain  Itoti- 
fera,  and  notices  their  cilia,  but  far  less  clearly 
than  his  predecessors..  Wrisbergft  observed  the 
currents  and  eddies  produced  by  the  vorticellae; 
at  least  he  saw  smaller  Infusoria  and  particles  of 
floating  matter  hurried  on  towards  their  mouths, 
but  he  seems  not  to  have  perceived  the  cilia. 

Otto  Frederick  Miiller,^  in  his  systematic 
work  on  the  Infusoria,  described  the  appear- 
ance and  arrangement  of  the  cilia  in  each 
species,  and  represented  them  in  figures.  He 
named  them  cilia  and  pili,  and  ascribed  to 
their  action  the  currents  and  vortices  which  the 
Infusoria  excite.  But  while  he  assigns  to  them 
the  office  of  locomotive  organs,  he  denies  that 
they  are  employed  in  seizing  food ;  for,  what 
is  singular,  in  his  long-continued  and  elaborate 
inquiries  into  the  economy  of  these  animals, 
he  could  never  perceive  that  foreign  matters 
drawn  into  the  mouth  were  retained  there  as 
nourishment,  but  believed  that  they  were 
always  again  thrown  out.  In  this,  however, 
he  was  undoubtedly  mistaken. 

*  Opuscules  de  Physique,  torn.  i.  p.  180. 
t  P.183. 

*  P.  199. 

$  Tom.  ii.  p.  227. 

||  Spallanzani,  Nouvelles  Recherches  sur  les 
Decouvertes  Microscopiques,  &c.  1769,  p.  161. 

^  See  Letter  by  Bonnet,  in  Spallanzani  Opus- 
cules, torn.  i.  p.  176. 

**  Elenchus  Zoophytorum,  1766. 

ft  Observationum  de  Animalculis  Infusoriis  sa- 
tur'a,  1765,  p.  52,  p.  63. 

JJ  Vermium  Terrestrium  et  Fluviatilium  His- 
toria,  1773,  and  Animalcula  Infusoria,  1788. 


CILIA. 


609 


Gleichen,*  in  1778,  described  the  currents 
produced  by  the  vorticellae.  In  an  earlier 
work  he  ascribed  an  agitation  of  small  bodies, 
•which  he  had  observed  in  the  neighbour- 
hood of  one  of  the  Infusoria,  to  an  electric 
or  magnetic  force,  not  having  perceived  the 
cilia.f 

FontanaJ  described  the  rotatory  apparatus 
of  the  Rotifer  and  its  use  ;  he  conceived  that  its 
apparent  rotation  was  produced  by  the  succes- 
sive elevation  and  depression  of  the  cilia  which 
encircle  it. 

Of  the  more  recent  writers  who  have  inves- 
tigated or  described  these  phenomena  in  the 
Infusoria,  I  may  mention  Dutrochet,§  Gruit- 
huisen,||  Agardh,H  Raspail,**  and  Ehren- 
berg.f -f  Raspail  denies  the  existence  of  cilia, 
attributing  their  appearance  to  an  optical  de- 
ception, an  opinion  which  is  undoubtedly 
erroneous.  Ehrenberg,  who,  of  all  recent  ob- 
servers, has  contributed  most  to  the  knowledge 
of  the  economy  and  natural  history  of  the 
Infusoria,  has  particularly  investigated  the 
structure  and  mode  of  action  of  their  cilia. 
The  substance  of  his  observations  has  been 
already  given. 

The  ciliary  motion  has  been  recently  ob- 
served in  the  embryoof  Infusoria  while  enclosed 
in  the  ovum.JJ 

2.  Polypi  and  Sponges.  —  a.  Fresh-water 
polypi.  The  phenomena  in  question  have  not 
been  discovered  in  the  Hydra,  which  is  the 
largest  and  best  known  of  the  Fresh-water 
Polypi;  but  they  have  been  seen  and  described 
by  many  observers  in  another  sort,  viz.  that 
known  by  the  names  of  the  Polype  a  panache, 
or  Plumed  Polype  of  Trembley,  the  Bell- 
flower  animal  of  Baker,  and  Plumatella,  Cris- 
tatella,  Alcyonella,  &c.  of  other  naturalists. 
The  Polypes  of  this  kind  are  connected  in 
groups  on  a  common  stock  or  stem,  (a,  o, 
Jig.  291,  which  represents  the  animal  magnified,) 
and  each  is  furnished  with  a  tube  (b,  b  ), 
into  which  it  can  wholly  withdraw  itself. 
From  time  to  time  they  advance  a  little  way 
out  of  the  tubes  and  display  a  double  row 
of  arms  or  tentacula  (c)  ranged  round  the 
mouth  in  the  figure  of  a  horse-shoe.  When 
the  arms  are  spread  out  in  this  manner,  cur- 
rents appear  in  the  surrounding  water,  which 
are  made  evident  by  the  motion  of  any  small 
particles  that  may  accidentally  or  intentionally 
be  suspended  in  it.  The  currents  pass  along 
the  tentacula,  the  water  being  drawn  towards 

*  Abhandlung  ueber  -die  Saamen  -und  Infusions 
Thierchen,  1778. 

t  See  Miiller,  Infus.  p.  87. 

j  Traite  sur  le  venin  de  la  Vipere,  etc.  1781, 
torn.  i.  p.  87. 

§  Sur  les  Rotiferes,  Ann.  du  Musee  d'Hist. 
Nat.  1812,  torn.  xix.  et  1813,  torn.  xx. 

II  Salzburg.  Med.  Chir.  Zeitung,  1818,  iv.  p. 
222. 

H  Ueber  die  Zauberkraft  der  Infusorien,  Nov. 
Act.  Acad.  Caes.  Leop.  torn.  x.  p.  127. 

**  Hist.  Nat.  de  1'Alcyonella  Fluviatile,  etc. 
Mem.  de  la  Soc.  d'Hist.  Nat.  torn.  iv.  and  Chimie 
Organique,  1833. 

ft  Abhandl.  d.  Akad.  der  Wiss.  zu  Berlin  fur 
1831. 

it  Wagner,  Isis,  1832,  p.  383. 


i.  291. 


them  from  every  side,  and  the  main  stream  at 
last  issues  from  the  midst  of  them,  appearing 
as  if  it  came  out  of  the  mouth,  from  which, 
however,  it  really  is  not  derived.  The  arms 
are  fringed  on  their  two  borders  with  a  mul- 
titude of  cilia,  (see  A,  a  single  arm  mag- 
nified,) set  close  together,  which  vibrate  in 
regular  succession,  their  motion  appearing 
like  progressive  undulations  along  the  ten- 
tacula. When  one  of  the  arms  is  cut  off,  it 
affects  the  water  in  the  same  way  as  when  con- 
nected with  the  animal,  its  cilia  impelling  the 
fluid  in  a  current,  or  carrying  the  separated 
arm  through  it,  according  as  it  is  fixed  or  free. 

As  to  the  use  of  these  motions,  it  may  be 
stated  that  they  serve  undoubtedly  for  renew- 
ing the  water  in  respiration,  and  probably  also 
to  convey  food  to  the  animal.  Steinbuch, 
however,  remarked  that  the  currents  were  most 
lively  in  pure  water,  and  that  the  extraneous 
matters  which  they  conveyed  seemed  rather  to 
incommode  the  animal,  which  endeavoured 
to  avoid  them  ;  and  from  this  he  inferred  that 
the  currents  served  chiefly  if  not  solely  for 
respiration. 

Trembley*  and  Bakerf  observed  the  currents 
produced  by  this  polype,  but  both  erroneously 
conceived  them  to  be  caused  by  agitation  of 
the  tentacula.  Roesel}  correctly  remarked 
that,  during  the  production  of  the  currents,  the 
tentacula  were  motionless,  but  not  perceiving 
the  cilia,  nor  being  aware  that  the  arms  when 
detached  still  produced  motion  in  the  water, 
he  supposed  that  the  currents  were  occasioned 
by  a  stream  issuing  from  the  mouth.  At 
length  Steinbuch§  discovered  that  separated 
tentacula  retained  the  power  of  impelling  the 
water;  he  distinguished  the  cilia  and  their 
motion  as  the  cause  of  the  impulsion,  and 

*  Mem.  pour  servir  a  1'Hist.  d'un  genre  de 
Polype  d'eau  douce,  1744,  p.  212. 

t  Of  Microscopes,  ii.  p.  309. 

j  Insecten  Belustigungen,  torn.  iii.  1755,  p. 
458. 

$  Analccten  neuer  Beobachtungcn  und  Unter- 
suchungen  fur  die  Naturkunde,  1802,  p.  89. 


610 


CILIA. 


Polype  of  a  Flwstra 
in  its  cell. 


more  correctly  described  the  course  of  the  cur- 
rents :  the  foregoing  description  is  in  a  great 
measure  taken  from  his  memoir.  Since  then 
several  others*  have  made  similar  observations, 
among  whom  we  may  mention  Raspail  as 
more  particularly  deserving  of  notice,  though 
he  here,  as  in  other  cases,  denies  the  existence 
of  cilia. 

b.  Marine  Polypi.— The  polypi  of  marine 
Zoophytes,  on  which  observations  'relating  to 
the  present  subject  have  been  made,  may  for 
our  purpose  be  conveniently  arranged  under 
three  principal  forms. 

The  first  form  of  polype  (fig.  292)  is  found 
in  Flustrae  and  cellular 
polypi  generally;  it  ex- 
ists also  in  some  spe- 
cies which  have  been 
classed  among  the  Ser- 
tulariae,  and  probably 
prevails  very  extensively 
in  different  tribes  of 
Zoophytes.  The  body 
(a,  b,  c),  which  is  gene- 
rally contained  in  a  cell, 
is  bent  on  itself,  some- 
what like  the  letter  Y  or 
V;  the  one  branch  (a) 
being  the  mouth  and 
throat,  the  other  (b)  the 
rectum  opening  by  an 
anus,  and  the  middle 
part  (c),which  is  of  a  dark 
and  often  of  a  brown  co- 
lour, being  the  stomach  probably  with  some 
accessory  organ.  The  mouth  is  surrounded 
with  a  variable  number  of  long  straight  ten- 
tacula  or  arms,  fringed  on  both  of  their  lateral 
margins  with  cilia.  When  the  arms  are  ex- 
panded, the  cilia  are  thrown  into  rapid  motion, 
which  has  the  appearance  of  undulations  pro- 
ceeding along  the  fringes,  upwards  on  one  side 
of  the  arm  or  from  its  root  to  the  point,  and 
downwards  on  the  other.  While  the  cilia  are 
thus  moved,  they  produce  currents  in  the  water, 
as  described  in  the  Fresh-water  Polype,  and 
here  also  the  currents  in  all  probability  serve 
for  respiration  and  the  prehension  of  food. 
Besides  these  motions  in  the  water  in  the 
neighbourhood  of  the  tentacula,  a  revolving 
motion  of  particles  is  observed  within  the 
body :  small  particles  of  extraneous  matter 
which  enter  the  throat  are  moved  round 
within  it ;  and  the  contents  of  the  stomach 
and  rectum  undergo  a  very  singular  revolving 
motion  round  the  axis  of  the  cavity.  These 
internal  motions,  Dr.  Grant  conjectured,  might 
be  owing  to  internal  cilia;  and  I  have  been 
able  to  satisfy  myself  of  the  actual  existence 
of  such  internal  cilia,  by  means  of  a  Wollas- 
ton's  doublet  of  one-thirty  fifth  of  an  inch  focus; 
they  are  very  evident  in  the  throat;  in  the 
stomach  they  are  most  distinct  in  the  part 
adjoining  the  rectum  (indicated  by  d  in  the 


*  Vaucher,    Bull,  de  la  Soc.  Philom.  An  xii.  ; 

Raspail,  Mem.   de   la  Soc.  d'Hist.  Nat.  de  Paris, 

for   1827;    Meyen    liber  Polypen,   Isis  1828,    p. 
1225. 


figure),  and  they  are  clearly  to  be  seen  on 
the  whole  internal  surface  of  the  rectum  (6). 

I  have  nowhere  more  clearly  seen  the  above- 
mentioned  phenomena  than  in  a  zoophyte, 
whose  polype,  though  differing  somewhat  from 
the  first  form,  may  yet  be  referred  to  it.  This 
zoophyte  (Jig.  293,  A,  B)  has  a  creeping  stem 

Fig.  293. 


(«,  a),  which  adheres  to  shells,  or  twines  round 
the  stems  and  branches  of  other  zoophytes, 
(as  b  in  the  figure) ;  the  polypes  are  supported 
on  soft  pliable  fleshy  stalks  (c),  which  the  crea- 
ture moves  from  time  to  time  ;  their  body  (d, 
and  B  more  magnified)  is  bell-shaped  and 
consists  of  a  transparent  brownish  skin  or 
envelope  containing  the  mouth  and  throat  (e), 
the  stomach  (g),  and  rectum  (A).  The  mouth, 
or  expanded  aperture  of  the  animal,  is  sur- 
rounded by  a  prominent  lip  or  border  (t,  i), 
to  which  the  arms  are  attached.  Cilia  are 
distinctly  visible  on  the  arms,  and  within  the 
mouth  and  stomach ;  they  are  moved  very 
briskly,  and  small  extraneous  particles  indi- 
cating currents  in  the  water  are  hurried  onwards 
towards  the  arms,  as  pointed  out  by  the  arrows 
at  k,k;  many  of  these  particles  descend  along 
the  inner  side  of  the  arms  to  their  base,  as 
shown  by  the  dotted  arrows  o,  o,  o,  and  thence 
into  the  cavity  of  the  mouth,  from  which,  after 
being  moved  about  for  some  time,  the  greater 
number  are  thrown  out.  It  would  seem  that 
the  particles  of  food  or  other  solid  matter, 
after  being  conveyed  to  the  inside  of  the  arms, 
take  then  a  different  course  from  the  stream 
of  water.  The  latter  passes  inwards  between 
the  arms,  and  issues  from  the  middle  of  the 
irregular  circle  which  they  form  (as  at  m,  m\ 
carrying  with  it  such  solid  matters  as  are  not 
arrested  on  the  arms;  but  the  bodies  which 
enter  the  mouth  are  slowly  carried  along  the 
inside  of  the  arms  (as  at  o,  o),  and  in  close 
contact  with  them  till  they  reach  their  base. 
The  motions  of  the  contents  of  the  stomach 
and  its  cilia  appeared  as  in  the  Flustrae. 
I  could  perceive  none  in  the  rectum.  Mr. 
Lister  has  described  the  same  phenomena  in  a 
zoophyte  closely  resembling  this  one  in  the 
structure  of  the  polypi,  but  differing  in  the 
character  of  the  stem.* 

*  Phil.  Trans,  for  1834,  p.  385. 


CILIA. 


611 


In  the  second  form  (fg.  294)  the  stem  and 
Fig.  294. 


Campanularia, 

brandies  are  formed  externally  of  a  tough 
(generally  horny)  substance,  and  within  this 
of  a  transparent  soft  tissue,  which  is  tu- 
bular and  contains  a  granular  matter.  The 
polypi  resemble  hydra ;  each  is  lodged  in 
a  horny  cell  (a,  a),  from  which  it  partially 
protrudes  itself;  one  orifice  surrounded  with 
tentacula  serves  both  for  receiving  aliment 
and  discharging  faeces ;  this  leads  to  a  stomach 
(6),  which  communicates  through  an  opening 
(c)  at  the  bottom  of  the  cell  with  the  interior 
of  the  tubular  stem  and  branches,  the  attached 
part  or  base  of  the  polype  being  continuous 
with  the  soft  internal  tube,  of  which  the  po- 
lypes might  be  regarded  as  a  prolongation. 
In  this  form  of  polype,  which  exists  in  most 
true  species  of  Sertularia,  Campanularia,  and 
Plumularia,  and  in  allied  genera,  the  tentacula 
or  arms  are  destitute  of  cilia  and  incapable 
of  giving  an  impulsion  to  the  water.  But  a 
very  remarkable  motion  has  been  observed  by 
Cavolini*  and  Mr.  Lister f  in  the  granular 
matter  contained  in  the  stem  and  branches. 
Although  this  motion  has  not  been  traced  to 
the  agency  of  cilia,  yet  as  it  is  connected  with 
our  subject,  I  shall  briefly  notice  it  here. 
When  the  stem  and  branches  of  the  above- 
named  zoophytes  are  examined  with  a  high 
magnifying  power,  a  current  of  granular  par- 
ticles is  seen  running  along  the  axis  of  the 
tube.  The  current,  which  is  compared  to  the 
running  of  sand  in  a  sand-glass,  after  con- 
tinuing one  or  two  minutes  in  the  same  direc- 
tion, changes  and  sets  in  the  opposite  one, 
in  which  it  continues  about  as  long,  and  again 
resumes  the  first,  thus  alternately  flowing 
along  the  stem  to  the  extremities  of  the 
branches,  and  back  again.  The  change  of 
direction  is  sometimes  immediate,  but  at  other 
times  the  particles  are  quiet  for  a  while,  or  exhibit 
a  confused  whirling  motion  for  a  few  seconds 
before  the  change  takes  place.  Mr.  Lister  has 
discovered  that  the  currents  extend  into  the 
stomachs  of  the  polypi,  in  which  and  in  the 

*  Memorie  per  servire  alia  storia  de'  Polypi 
Marini,  p.  121  and  197 ;  p.  56  and  91  of  the  Ger- 
man Translation. 

t  Phil,  trans.  1834,  p.  369. 


mouth  a  remarkable  agitation  of  particles  is 
perceptible.  When  these  particles  are  allowed 
to  escape  from  a  cut  branch,  they  exhibit, 
according  to  Mr.  Lister,  something  very  like 
spontaneous  motion.  The  immediate  cause  of 
these  currents  is  not  apparent ;  it  seems  not  to 
be  muscular  contraction  of  the  tube ;  perhaps, 
like  the  agitation  within  the  stomach,  they 
may  be  owing  to  internal  cilia.  As  to  their 
use  Mr.  Lister  supposes  the  circulating  matter 
"  to  be  a  great  agent  in  absorption,  and  to 
perform  a  prominent  part  in  the  obscure  pro- 
cesses of  growth ;  and  its  flow  into  the  stomach 
of  the  polypi  seems  to  indicate  that  in  this 
very  simple  family  (the  Sertulariae)  it  acts  also 
as  a  solvent  of  the  food." — Page  77.  Perhaps 
the  polypi  of  the  Pennatula  and  Virgularia 
should  be  referred  to  this  head.  In  these 
Dr.  Grant*  discovered  a  constant  vibratory 
motion  within  the  mouth,  apparently  pro- 
duced by  cilia  placed  round  the  entrance  of 
that  passage,  and  he  saw  minute  particles  oc- 
casionally propelled  from  the  mouth.  Their 
tentacula,  as  in  the  zoophytes  last  referred  to, 
did  not  excite  currents. 

The    third    form  of  polype    is    found    in 
Tubularia.     Fig.  295   represents  a  magnified 
view   of   a  common  species, 
the  Tubularia  indivisa.  There        Fig.  295. 
is  a  transparent  horny  tube 
(a,  a),  containing  a  soft  mat- 
ter, which  at  the  extremity  of 
the  tube  is  continuous   with 
the  stomach  (6)  and  the  mouth 
(c).     There  are  two  rows  of 
tentacula  or  arms,    one   (e?) 
immediately  surrounding  the 
orifice    of   the  mouth,      the 
other   (e)    further  back,    be- 
tween the  mouth  and  stomach.  j1 
The     arms    are   destitute   of 
cilia  and  excite  no  movement 
in  the  water;  but  Mr.  Listerf 
has  discovered  a  remarkable 
motion  of  particles  within  the 
tube,   which    has    some    re- 
semblance to  the  circulation 
of  globules  observed  in  plants 
of  the  genus  Chara.     These 
particles  moved  in  a  current 
within  the  tube,  the   general 
course   of  the  stream    being 
parallel  to  the  slightly  spiral 
lines   of   spots  on  the   tube, 
and  in  the  directions  marked         Tubularia 
by  the  arrows.  On  the  greater          indivisa. 
part  of  the  side  first  viewed 
(the  one  represented)  it  set  as  from  the  poly- 
pus ;  but  on  the  other  side  the  flow  was  to- 
wards the  polypus,  each  current  thus  occupy- 
ing half  the  circumference.     The  tube  had  a 
granulated   appearance   between    the  lines   of 
spots,  and  beneath  this  the  particles  ran.    Their 
course   was    even   and    uniform  without   any 
starting  or  dancing  motion,  such  as  is  observed 
in  the  Sertulariae.     At  the  nodous  parts  of  the 

*  Edin.  Ph:.l.  Journ. 

t  Phil.  Trans.  1834,  p.  366. 


612 


CILIA. 


tube  (m,  n)  were  slight  vortices  in  the  current, 
and  at  o  near  the  end  of  the  tube  it  came  over 
from  the  opposite  side.  Two  currents  were 
continually  going  on  in  the  mouth  and 
the  stomach,  one  always  flowing  down  the 
sides  in  the  direction  e,  e,  and  the  opposite 
one  in  the  axis.  Neither  the  cause  of  these 
currents  nor  their  use  has  been  ascertained. 

Such  are  the  phenomena  of  the  ciliary  and 
other  apparently  allied  motions  in  the  Marine 
Polypi. 

Spallanzani  seems  to  have  first  noticed 
them;  he  observed  the  currents  produced 
by  the  Flustrae,  but  erroneously  attributed 
them  to  the  agitation  of  the  arms,  the 
cilia  on  which  he  had  not  perceived.  Dr. 
Fleming*  described  the  current  along  the 
tentacula  in  the  Valkeria  cuscuta  (a  genus 
which  he  has  separated  from  the  Sertulariae, 
among  which  it  was  previously  included,)  and 
distinguished  the  cilia  with  their  undulatory 
motion.  Dr.  Grantf  discovered  the  cilia  on 
the  arms  of  the  Flustrae  and  described  their 
undulatory  motion,  to  which  he  ascribed  the 
motion  iu  the  water.  He  also  pointed  out  the 
revolving  motion  of  particles  within  the  mouth, 
stomach,  and  rectum,  and  conjectured  that  it 
was  owing  to  the  action  of  internal  cilia, 
which  conjecture  I  have  been  able  to  verify. 
Dr.  Grant  also  discovered  the  vibratory  and 
probably  ciliary  motion  within  the  mouth  of 
the  polype  of  the  Pennatulae.  LoeflingJ 
first  observed  the  agitation  of  granular  matter 
within  the  stem  and  branches  of  the  Sertu- 
lariae. Cavolini  afterwards  more  correctly  de- 
scribed this  as  a  current  of  fluid  holding 
granules  in  suspension,  running  first  in  one 
direction  and  then  in  the  other.  Lastly,  Mr. 
Lister  observed  anew  these  internal  currents 
of  the  Sertulariae,  described  them  more  mi- 
nutely, and  showed  that  they  extended  into 
the  stomach  of  the  polypes.  Mr.  Lister  has 
also  described  the  phenomena  in  the  Flustrae 
previously  observed  by  Dr.  Grant.  He  dis- 
covered the  currents  within  the  stem  of  the 
Tubularia,  which,  as  far  as  I  know,  had  not 
been  previously  noticed. 

c.  Sponges. — In  the  various  species  of 
sponges,  water,  the  element  in  which  they 
live  and  grow,  passes  in  currents  through 
pores  and  canals  in  their  substance,  in  a  con- 
tinuous manner,  entering  at  one  place  and 
issuing  at  another.  This  phenomenon  has  not 
been  directly  traced  to  the  agency  of  cilia ;  it 
comes  nevertheless  to  be  considered  here,  as 
such  an  agency  is  highly  probable,  and  at 
least  the  motion  of  the  water  is  not  owing  to 
any  contraction  of  the  canals  in  which  it  flows, 
but  is  obviously  caused  by  some  other  kind  of 
impulsion  communicated  to  it  by  the  surface 
along  which  it  passes. 

In  a  common  sponge  we  see  a  number  of 
pretty  large  orifices  on  the  surface,  each  opening 
on  the  summit  of  a  conical  eminence  or  pa- 
pilla (Jig.  296,  a).  These  openings  are  named 

*  Mem.  of  Wern.  Soc.  fol.  p.  v.  p.  488. 
t  On  the  Structure  and  Nature  of  Flustrae.    Ed. 
New  Phil.  Journal,  vol.  iii.  1827. 

t  Schwedische  Abhandlungen,  1752,  p.  121. 


Fig.  296. 


Sponge. 

by  Dr.  Grant  the  "  faecal  orifices."  Innume- 
rable small  pores  occupy  the  rest  of  the  surface, 
and  give  to  it  its  peculiar  character.  These 
pores  penetrate  to  a  certain  depth,  and  lead 
into  canals  (6),  which,  uniting  together  and 
gradually  growing  larger,  terminate  in  wide 
tubes,  which  open  at  the  faecal  orifices.  The 
pores,  excretory  canals,  and  faecal  orifices  thus 
form  continuous  passages  through  the  sponge. 
In  the  fresh  state  they  are  lined  throughout  with 
a  smooth  gelatinous  coating. 

When  a  living  sponge  is  examined  atten- 
tively in  its  native  element,  the  water  is  per- 
ceived entering  at  the  pores  and  issuing  from  the 
faecal  orifices,  its  course  being  indicated  by  the 
motion  of  any  floating  particles  that  may  be 
present.  The  issuing  currents  are  stronger 
than  the  entering,  and  are  rendered  con- 
spicuous by  excrementitious  matters  or  some- 
times ova,  conveyed  out  at  the  faecal  orifices. 

When  sections  of  the  sponge,  including  a 
greater  or  less  extent  of  the  internal  canals, 
are  placed  in  water,  the  fluid,  according  to 
Dr.  Grant's  observations,  is  still  evidently 
moved  along  the  internal  surface  of  the  portions 
of  canals,  although  their  continuity  with 
the  rest  is  destroyed.  Dr.  Grant  could  not 
detect  cilia  either  in  these  canals  or  the  pores 
which  lead  to  them,  but  he  discovered  these 
organs  on  the  ova  of  the  sponge,  which  there- 
by execute  remarkable  spontaneous  motions, 
and  he  is  inclined  to  attribute  the  currents  in  the 
adult  sponge  also  to  cilia,  which  he  conceives 
may  probably  exist,  though,  from  their  small- 
ness,  he  has  not  been  able  to  perceive  them.  At 
any  rate  he  has  shewn  by  most  satisfactory 
observations,  that  the  current  cannot  be  ascribed 
to  contractions  in  the  canal,  for  in  none  of  his 
numerous  experiments  instituted  for  the  pur- 
pose, could  he  discover  any  sign  of  irritability, 
at  least  any  sign  of  contraction  of  the  tissue 
of  the  sponge  on  the  application  of  stimuli. 

Naturalists  even  of  the  earliest  times,  whose 
attention  was  directed  to  the  phenomena  exhi- 
bited by  the  living  sponge,  have  remarked  that 
water  entered  and  passed  out  from  its  porous 
substance,  but  the  true  course  of  the  fluid 
seems  to  have  been  unknown,  it  having  been 
erroneously  supposed  to  enter  and  issue  by  the 
same  orifices.  Dr.  Grant,*  to  whose  labours 
we  owe  most  of  the  correct  information  ob- 
tained respecting  the  structure  and  functions  of 
the  sponge,  demonstrated  that  the  current  is 
continuous,  and  flows  always  in  one  direction 
as  above  described,  and  proved  that  the  motion 

*  Edin.  Phil.  Journal,  vols.  xiii.  xiv.  Edin. 
New  Phil.  Journal,  vols.  i.  and  ii. 


CILIA. 


613 


of  the  water  was  not  produced  by  contraction 
and  dilatation  of  the  tissue  of  the  sponge, 
which  he  showed  to  be  destitute  of  irritability. 
Dutrochet  had  made  observations  on  the  same 
subject,  which  were  published  subsequently* 
to  those  of  Dr.  Grant,  and  not  anteriorly  as  he 
supposes;  he  perceived  the  constant  direction 
of  the  current,  and  ascribed  the  phenomenon  to 
endosmosis  and  exosmosis. 

3.  Ciliary  motion  of  the  ova  of  Polypi  and 
Sponges. — The  ova  or  gemmules  of  several  of 
these  zoophytes  execute  independent  move- 
ments, and  produce  currents  in  the  surrounding 
water.  This  singular  fact  was,  it  appears, 
first  noticed  by  Mr.  Ellis  in  1755,f  in  ex- 
amining a  species  of  Sertularia,  the  Campanu- 
laria  dichotoma ;  but  he  described  the  ova  or 
embryos  which  he  had  seen  in  motion,  as 
young  polypi,  already  somewhat  advanced  in 
their  formation.  Cavolini,|  in  1784  and  1785, 
observed  the  same  phenomenon  in  the  ova  of 
the  Gorgonia  and  Madrepore,  and  investigated 
it  more  fully.  lie  saw  the  egg-shaped  gem- 
mules  or  ova,  on  quitting  the  parent,  rise  to 
the  surface,  and  swim  with  their  large  end  for- 
wards, in  a  horizontal  direction,  till  they  fixed 
themselves  on  some  spot  where  they  were  deve- 
loped. Dr.  Grant,§  in  1825,  discovered 
similar  motions  in  the  ova  of  the  sponge,  and 
detected  the  moving  cilia.  The  cilia  covered 
the  whole  surface  of  the  ovum,  except  the  pos- 
terior tapering  extremity,  and  in  its  motions 
the  large  end  of  the  ovum  was  always  directed 
forwards.  When  an  ovum  fixed  itself,  its  cilia 
still  continued  to  play,  by  which  a  current 
along  its  surface  was  kept  up  for  some  time. 
Dr.  Grant  also  investigated  the  movements  of 
the  ova  of  the  Campanularia,  previously  seen 
by  Ellis,  and  of  the  Plumularia  falcata.  The 
ova  of  both  these  zoophytes  are  contained 
within  transparent  capsules,  two  or  more  being 
in  each  capsule,  surrounded  by  a  clear  fluid. 
Dr.  Grant  distinctly  perceived  cilia  vibrating 
on  the  surface  of  the  ova,  and  causing,  while 
within  the  capsule,  an  eddying  motion  of  the 
surrounding  fluid,  but  propelling  the  ova 
through  the  water  when  extracted  from  their 
capsule,  as  in  the  sponge.  The  ciliary  motion 
has  also  been  found  in  the  ova  of  fresh-water 
polypi,  having  been  discovered  by  Meyen||  in 
those  of  the  Alcyonella  stagnorum,  which  is 
probably  the  same  with,  or  at  least  nearly 
allied  to  the  Bell-flower  Polype. 

By  means  of  the  remarkable  provision  here  de- 
scribed, the  ova  of  these  fixed  zoophytes  are  dis- 
seminated, and  conveyed  to  situations  suitable 
to  become  the  abode  of  the  future  individuals. 
The  same  provision  undoubtedly  serves  also  to 
move  the  water  along  their  surface  for  the  pur- 
pose of  respiration.  It  exists,  as  will  be  after- 


*  L'agent  immediat  dumouvement  vital  devoile, 
1826,  p.  179,  and  Annales  des  Sciences  Naturelles, 
1828,  torn.  xv.  p.  205. 

t  Hist.  Nat.  des  Corallines,  p.  116. 

J  Memorie  per  servire  alia  storia  de'  Polypi 
Marini,  Nap.  1785,  p.  8,  p.  48  of  German  trans- 
lation. 


<S  Edin.  New  Phil.  Journal,  vol.  i.  p.  150. 


Isis,  1828,  p.  1225,  sqq.    Isis,  1830,  p.  186. 


wards  shown,  in  the  ova  of  many  other  ani- 
mals. 

4.  AcalephtK. — Many  species  of  Medusae  are 
furnished  with  cilia,  or  at  least  with  moving 
organs  bearing  a  close  resemblance  to  the  cilia 
of  other  animals,  though  in  the  Medusae  they 
present  several  peculiarities.  The  cilia  are 
found  in  all  the  Medusae  belonging  to  the  order 
Ciliograda  of  Blainville,  or  Ctenophora  of 
Eschscholz,  of  which  the  genus  Beroe  is  a 
good  example.  Eschscholz*  describes  them  as 
small  pectinated  or  comb-like  organs,  ranged 
in  longitudinal  rows  or  stripes  on  the  external 
surface  of  the  body,  with  their  flat  surfaces  in 
apposition.  Each  comb-like  organ  consists  of 
many  small,  flattened,  pointed  filaments,  united 
together  by  a  common  base,  the  points  being 
directed  towards  the  posterior  extremity  of  the 
body.  They  are  moved  like  fins,  being  slowly 
raised  and  suddenly  struck  back,  by  which 
means  the  body  is  carried  through  the  water. 
In  the  Beroe  and  others  of  similar  form,  the 
cilia  point  towards  the  closed  extremity  of  the 
body,  so  that  the  opposite  or  open  end  is 
carried  forward.  The  animal  seems  to  have 
the  power  of  moving  more  or  fewer  of  these 
organs  as  it  may  incline,  by  which  means  other 
motions  besides  direct  progression  are  per- 
formed. The  cilia,  when  separated  from 
the  body  with  a  piece  of  skin,  continue  to 
move  briskly  for  some  time.  A  longitudinal 
vessel  runs  under  each  row  of  cilia,  com- 
municating with  the  rest  of  the  vascular 
system,  and  containing  a  fluid,  in  which  yel- 
lowish particles  are  suspended.  Eschscholz 
regards  these  vessels  as  arteries,  and  considers 
1  the  cilia  as  respiratory  as  well  as  locomotive 
organs.  Dr.  Grant,  in  describing  the  cilia  of 
the  Beroe  pileus,f  represents  the  parallel  fila- 
ments of  which  the  comb-like  organs  consist, 
as  united  together  by  a  membrane  as  far  as 
their  points,  like  the  rays  in  the  fin  of  a  fish. 

Schweigger  compares  the  vessels  which  run 
underneath  the  rows  of  cilia,  to  the  canals  com- 
municating with  the  tubular  feet  of  the  Sea- 
urchin  arid  Asterias ;  and  Dr.  Grant  seems 
also  inclined  to  ascribe  the  motion  of  the  cilia, 
whose  filaments  he  conceives  to  be  tubular,  to 
their  being  alternately  filled  and  emptied  of 
fluid  derived  from  the  longitudinal  vessel,,  like 
the  tubular  feet  of  the  Echinodermata.  This 
view  of  their  mode  of  action,  however,  is 
scarcely  reconcilable  with  the  observed  phe- 
nomena, as  will  be  afterwards  shown  in  con- 
sidering the  structure  of  the  cilia  in  general. 
Audouin  believed  that  in  the  Idya,  a  genus 
nearly  allied  to  the  Beroe,  the  fluid  of  the 
longitudinal  vessel,  which  he  supposes  to  be 
water,  is  sent  into  the  cilia;  he  therefore 
regarded  them  as  respiratory  organs.  If  the 
vessel  under  the  cilia  in  this  case,  as  in  the 
Beroe,  communicate  with  the  rest  of  the  vas- 
cular system,  and  its  contained  fluid  be  re- 
garded as  blood,  then  the  cilia  of  the  Idya, 
which,  according  to  Audouin,  are  permeated 
by  the  fluid,  would  bear  a  certain  analogy  to 
the  gills  of  fishes. 

*  System  der  Acalephen,  p.  3. 
t  Zoological  Trans,  vol.  i.  p.  9. 


614 


CILIA. 


Cilia  appear  also  to  exist  in  other  tribes  of 
Medusae  besides  the  Ciliograda,  but  they  differ 
in  form  and  situation  from  those  described, 
and  have  not  been  investigated  with  equal 
accuracy. 

In  Rhizostoma  there  are  certain  membranous 
appendages  attached  to  the  arms  or  tentacula, 
and  bearing  on  their  free  edge  a  fringe  of  short 
filaments  which  are  constantly  in  motion,  and 
continue  so  for  some  time  after  the  arm  or 
portion  of  membrane  supporting  them  is  de- 
tached from  the  body.  These  filaments  are 
described  and  figured  by  Eysenhardt,*  who 
regards  them  as  organs  of  generation  ;  they  are 
probably  of  the  nature  of  cilia.  Similar  fila- 
mentary organs  seem  also  to  exist  within  the 
body  in  some  Medusae.  (See  ACALEPHJE, 
p.  48.) 

5.  Actinia. — In  a  paper  published  on  the 
present  subject  in  1830,^  I  mentioned  that  I 
had  found  the  ciliary  motion  in  the  Actinia  or 
Sea-anemony,  but  gave  no  description  of  it.  I 
have  since  re-examined  various  species  of 
Actiniae  with  this  view,  and  shall  now  describe 
the  appearances ;  but  to  make  the  description 
intelligible,  it  may  not  be  improper  to  remind 
the  reader  of  some  points  in  the  anatomy  of 
these  animals  which  require  to  be  kept  in 
view. 

The  body  of  the  Actinia,  of  which  Jig.  297 

Fig.  297. 


Actinia. 

is  a  plan,  consists  entirely  of  a  soft  but  tough 
substance,  exceedingly  contractile  and  irritable. 
It  is  usually  cylindrical  in  shape,  one  end, 
(a,  a,)  named  the  base  or  foot,  serving  to  fix 
the  animal  by  adhering  to  rocks  or  other  ob- 
jects ;  the  other  extremity  is  named  the  disc, 
one-half  of  which  is  seen  at  6,  b,  the  other 
half  being  removed  by  a  section;  it  is  sur- 
rounded at  its  circumference  by  the  arms  or 
tentacula  (c,  c,)  in  concentric  rows,  and  in  its 
centre  is  the  mouth  (d),  or  opening  of  the 
stomach,  which  serves  both  for  the  entrance  of 
food  and  discharge  of  undigested  remains. 

*  Nova  Acta  Acad.  Caes.  Leop.  vol.  x.  p.  404. 
t  Edin.  Med.  and  Surg.  Journal,  vol.  xxxiv. 


The  stomach  (e)  is  plaited  longitudinally  on 
its  inside;  vertical  membranous  partitions 
(g>  g>  8>  g',)  pass  from  its  outer  surface  to  the 
inside  of  the  parietes  of  the  body,  and  to  the 
base,  dividing  the  intermediate  space  into 
numerous  compartments  or  cells,  which  com- 
municate with  each  other  by  openings,  as  at 
g',  g',  and  also  open  into  the  tentacula,  as  at  h. 
The  latter  are  conical  muscular  tubes,  commu- 
nicating at  their  base  with  the  cells,  and  open- 
ing at  their  point  by  a  small  orifice,  surrounded 
by  a  sphincter  muscle.  The  cells  seem  also 
to  communicate  with  the  cavity  of  the  stomach, 
and,  according  to  Rapp,*  they  open  in  some 
species  by  small  orifices  on  the  surface  of  the 
body.  The  cells  and  tentacula  contain  sea- 
water,  with  which  the  animal  can  distend  the 
whole  body  or  any  particular  part  of  it.  The 
protrusion  of  the  tentacula,  as  is  well  known, 
is  effected  by  their  distension  with  water.  The 
stomach  also  is  often  partially  everted  and  pro- 
truded from  the  mouth  by  an  accumulation  of 
water  behind  it.  It  has  not,  so  far  as  I  know, 
been  clearly  shewn  by  which  of  the  communi- 
cating orifices  the  water  enters.  Though  I 
took  considerable  pains,  I  have  not  been  able 
satisfactorily  to  ascertain  this  point;  I  may 
remark,  however,  that  I  have  repeatedly  no"- 
ticed  water  entering  at  the  mouth. 

The  ovaries  and  oviducts  (/c,  /c,)  are  lodged 
in  the  cells,  and  are  consequently  bathed  in 
water ;  of  these  it  is  unnecessary  here  to  say 
more  than  that  one  part  of  them  consists  of  a 
waving  membranous  fold  like  a  mesentery,  at- 
tached by  one  edge  to  the  sides  of  the  cell,  and 
at  its  free  border  supporting  the  oviduct, 
which  resembles  a  white  opaque  chord,  termi- 
nating, after  numerous  serpentine  windings,  in 
the  stomach. 

In  regard  to  the  ciliary  motion  in  the  Actiniae, 
I  am  led  from  my  observations  to  conclude  that . 
it  exists  to  a  greater  extent  in  some  species  than 
in  others.  In  all  cases  I  have  found  it  on  the  sur- 
face of  the  oviducts  and  their  supporting  mem- 
branes, which  is  covered  with  cilia  of  very  minute 
size ;  also  on  the  internal  surface  of  the  sto- 
mach, which  has  similar  cilia,  and  there  the 
currents  follow  the  direction  of  the  folds  of  the 
membrane.  In  one  small  but  full-grown  species 
I  found  currents  commencing  near  the  centre 
of  the  disc,  and  proceeding  outwards  in  a 
radiating  manner  to  its  circumference,  whence 
they  continued  along  the  arms  as  far  as  the 
points.  On  examining  this  species,  which 
was  semitransparent,  by  transmitted  light,  I 
distinctly  perceived  moving  particles  in  the 
water  contained  within  the  tentacula  and  be- 
hind the  protruded  stomach  .f  The  motion  of 
these  particles  obviously  indicated  a  current  in 
the  water  along  the  surfaces  containing  it, 
which  current,  like  that  on  the  oviducts,  it 
may  be  inferred  was  produced  by  cilia,  for  it 
went  on  while  there  was  no  perceptible  con- 
traction taking  place  in  any  part  of  the  ani- 
mal. The  particles  indicating  the  currents 

*  Ueber  die  Polypen  und  die  Actinien.  Weimar, 
1829,  p.  47. 
t  Some  of  these  particles  were  no  doubt  the  ova. 


CILIA. 


615 


within  the  tentacula,  were  moved  in  two  diffe- 
rent directions,  namely,  from  the  base  to  the 
point,  and  from  the  point  to  the  base ;  and 
(supposing  the  arm  spread  out  horizontally,) 
the  outward  current  was  along  the  under  part 
of  the  tube,  and  the  returning  one  along  the 
upper:  (see  A.)  I  also  observed  these  internal 
currents  of  the  tentacula  in  a  young  specimen  of 
Actinia  senilis,  which  seemed  to  have  been  very 
recently  discharged  from  the  parent ;  in  it  also 
there  were  radiating  currents  on  the  disc,  but 
they  stopped  at  the  base  of  the  tentacula. 
Thus  the  external  currents  on  the  disc  and  ten- 
tacula were  found  in  one  species,  and  they 
occur  on  the  disc  in  some  other  species  in  the 
young  state,  but  their  occurrence  in  this  situa- 
tion is  by  no  means  general  in  adult  Actiniae. 

The  phenomena  described  are  in  all  proba- 
bility connected  with  the  processes  of  nutri- 
tion and  respiration.  They  bear  a  striking 
analogy  to  those  I  have  observed  in  the  Echino- 
dermata. 

The  ova  of  the  Actiniae  were  observed  by 
Rathke  to  revolve  round  their  axis,  and  occa- 
sionally to  move  straightforward s  in  the 
water.  He  could  detect  no  cilia  or  other 
moving  organs.* 

6.  Echinodermata. — The  animals  of  this 
class  in  which  I  have  observed  the  ciliary 
motion,  are  different  species  of  the  Sea-star 
(Asterias),  and  the  Sea-urchin  (Echinus).  In 
proceeding  to  describe  the  phenomena  in  the 
Asterias,  I  must  first  take  the  liberty  of  ex- 
plaining some  points  in  the  anatomy  of  that 
animal,  referring  the  reader  for  other  details  to 
the  proper  sources,  especially  the  monograph 
of  Tiedemann.f 


On  the  under  surface  of  the  Asterias,  (I 
speak  of  the  Asterias  rubens  in  particular, 
Jig.  298,  A,  B,  C,  as  it  is  a  large  species  and 
common  on  our  shores,)  we  observe  the  mouth 
in  the  centre,  and  the  tubular  feet  (7,  Jig.  B) 
projecting  in  rows  along  the  under  part  of  the 
rays.  Nearly  the  whole  surface  of  the  animal 
is  beset  with  three  kinds  of  eminences.  First, 
hard  calcareous  processes,  (a,  Jig.  C,)  placed 
like  studs  at  some  distance  from  each  other. 
Secondly,  claw-like  processes  (b,  6) ;  these  sin- 
gular organs  are  more  thickly  set ;  they  consist 
of  a  solid  stem  of  soft  substance,  bearing  at  the 
extremity  a  sort  of  pincers  or  forceps  of  hard 
calcareous  matter,  like  the  claw  of  a  crab. 
They  resemble  analogous  organs  found  on  the 
Sea-urchin,  only  that  the  maxillae  or  pincers  in 
the  latter  consist  of  three  pieces ;  they  were 
named  antennae  or  feelers  by  Monro,  but  Miil- 
ler  regarded  them  as  parasitical  animals.  The 
third  sort  of  processes  (c,  c,)  are  named  the 
respiratory  tubes,  and  are  the  most  important 
in  regard  to  our  present  subject.  They  are 
short,  conical,  membranous  tubes,  communi- 
cating at  their  base  with  the  internal  cavity  of 
the  body,  and  perforated  at  their  point  by  an 
orifice  which  can  be  very  perfectly  closed. 
Most  of  them  are  placed  in  groups  or  patches, 
and,  corresponding  with  each  group  of  tubes, 
the  fibrous  membrane  forming  the  wall  of  the 
body  presents  on  its  inside  a  pit  or  shallow 
depression  (e),  perforated  with  holes,  through 
which  the  tubes  communicate  with  the  general 
cavity.  Like  the  tentacula  of  the  Actiniae, 
which  they  resemble  in  several  other  respects, 
they  can  be  distended  with  water  and  elon- 
gated, or  emptied,  contracted,  and  shortened. 


iff.  298. 


B 


A ,  Asterias  viewed  from  above.        B,  Cross  section  of  a  Ray.         C,  Part  of  the  section  at  m,  Jig.  A,  magnified. 


*  Dorpater  Jahrbuch.  fur  Litt.  Stat.  und  Kunst. 
Bd.  i.  Heft.  i.  p.  84—86,  quoted  by  Purkinje  and 
Valentin,  p.  32.  I  have  since  seen  the  indepen- 
dent motion  of  the  ova  when  extracted  from  the 
animal.  It  was  shown  to  me  by  Mr.  Graham 


Dalyell,  who  had  long  before  observed  it.    The  cilia 
could  be  distinctly  perceived. 

f  Anatomic  der  Rbhren  Holothurie,  &c.  Land- 
shut,  1816. 


616 


CILIA. 


In  the  inside  of  the  body  the  membranous 
stomach  (g)  occupies  the  middle  part,  and 
from  it  a  pair  of  lobed  coeca  (h,  hj  (and  i,  i,  cut 
short)  pass  into  each  ray.  Within  the  rays  also 
we  find  inferiorly  the  rows  of  vesicles  (k,  k) 
which  form  part  of  the  feet  (I,  I),  and  the 
ovaries.  All  the  rays  communicate  through 
the  middle  part,  and  the  whole  inside  is  lined 
by  a  transparent  membrane  (n,  n)j  which, 
like  a  sort  of  peritoneum,  covers  the  stomach 
and  cceca,  attaches  each  of  the  creca  by  a  me- 
sentery (of  o)  to  the  roof  of  the  ray,  lines  the 
fibrous  parietes  of  the  body,  and  is  probably 
reflected  over  the  vesicles  of  the  feet  and  the 
ovaries.  Each  mesentery  encloses  a  space 
(°i  fis-  B)  between  its  sides,  which  opens  into 
the  general  cavity  at  the  root  of  the  cceca.  The 
lining  membrane  passes  into  the  perforated 
pits  ( e)j  by  which  the  tubes  (c)  communicate 
with  the  cavity,  and  sends  prolongations  through 
the  perforations  into  the  tubes  lining  them  to 
their  points.  The  space  (s,  *,  jig.  B)  lined  by 
this  membrane  contains  sea-water,  which  is 
generally  described  as  entering  and  issuing  by 
the  respiratory  tubes.* 

I  find  the  ciliary  motion  in  four  situations, 
namely,  1.  on  the  external  surface;  .2.  within 
the  cavity  of  the  body,  or  in  the  space ^(s) 
between  its  parietes  and  the  viscera  ;  3.  within 
the  stomach  and  coeca;  4.  within  the  feet. 
In  all  these  situations  moving  cilia  are  visible 
with  the  microscope  on  the  respective  surfaces; 
they  are  every  where  comparatively  small,  in 
some  parts  excessively  so.  Though  I  have  not 
traced  them  over  the  entire  extent  of  each  sur- 
face, I  have  no  doubt  they  exist  at  every  point 
where  currents  are  produced. 

1.  On  the  external  surface.    The  ciliary  mo- 
tion as  indicated  by  the  application  of  pow- 
dered charcoal,  occurs  over  nearly  its  entire 
extent,  but  with  different  degrees  of  intensity. 
The  strongest  currents  pass  along  the  outer 
surface  of  the  tubes  from  the  base  to  the  point, 
as  at  c  ;   they  are  also  pretty  strong  on  the 
claw-like  processes  (V)  and  intermediate  skin; 
on  the  feet  they  are  evident  but  less  vigorous. 

2.  Within  the  body  the  currents  take  place 
on  the  lining  membrane  and  its  reflections.     A 
longitudinal  current  runs  along  the  roof,  and 
another  along  the  floor  of  each  ray,  forwards 
or  towards  its  point :  (see  the  arrows  in  jig.  A.) 
These  advancing  currents  are  confined  to  the 
median  line  and  its  immediate  vicinity;   two 
retiring  currents  (r,  r,)  run  backwards  (one  on 
each  side)  at  the  place  where  the  sides  join  the 
floor  of  the  ray.  Two  longitudinal  currents  also 
exist  on  each  of  the  coeca,  an  advancing  one 
(h')  on  the  inferior  surface,  and  a  retiring  one 
superiorly  (h,  h,  fig.  A)  in  the  space  (o,jig.  B) 
inclosed  within  the  mesentery,  which,  as  already 
mentioned,  opens  into  the  general  cavity.    The 
longitudinal  currents,  except  those  within  the 
mesentery,  are,  if  for  the  sake  of  explanation 

*  Without  denying  this  mode  of  entrance,  1 
may  yet  mention,  that  though  I  have  often  seen 
the  animal  slowly  distending  itself  with  water,  and 
again  partially  emptying  itself,  1  could  never  per- 
ceive the  fluid  entering  or  issuing  at  the,  orifices 
described. 


we  may  so  express  it,  connected  by  others 
which  run  vertically  and  transversely  on  the 
coeca  and  on  the  roof  and  sides  of  the  cavity, 
(see  the  arrows  in  Jig.  B;)  on  the  vesicles  of  the 
feet  the  course  of  these  cross  currents  is  varied 
by  the  curved  surfaces.  As  the  lining  membrane 
of  the  cavity  extends  into  the  respiratory  tubes, 
so  currents  exist  within  these  likewise,  as  at  t, 
jig.  C.  This  is  proved  by  injecting  turbid 
fluid  into  the  ray,  when  particles  are  seen 
moving  within  the  tubes ;  and  if  a  few  of  the 
tubes  with  a  portion  of  the  skin  be  cut  off  and 
placed  under  the  microscope,  the  fluid  which 
will  still  be  retained  by  some  of  them  may  be 
seen  to  be  in  motion,  the  floating  particles 
moving  from  the  base  to  the  point  and  back 
again,  as  in  the  arms  of  the  Actiniae. 

3.  The  motion  is  very  distinct  on  the  inner 
surface  of  the  stomach  and  coeca ;  the  currents 
within  the  coeca  follow  the  same  direction  as  on 
their  external  surface,  that  is,  an  advancing 
current  runs  inferiorly  from  the  root  to   the 
point  and  a  returning  one  superiorly ;  and  at 
the  sides  currents  run  upwards,  following  the 
ridges  or  folds  of  the  internal  membrane  which 
result   from   the    lobulated    structure    of   the 
cceca. 

4.  The  ciliary  motion  exists  distinctly  within 
the  feet,  though  the  cilia  are  very  small ;  these 
became  visible  on  viewing  the  edge  of  a  folded 
portion  with  Wollaston's  doublet  of  one-thirty- 
fifth  of  an  inch  focus. 

The  currents  described,  as  far  as  I  have  been 
able  to  perceive,  preserve  always  the  same 
determinate  direction.  Even  when  portions  of 
the  ciliated  surface  are  detached,  the  motion 
on  them  continues,  and  its  direction  is  the 
same  as  before  their  separation. 

As  to  the  use  of  these  motions,  it  is  most 
probably  connected  chiefly  with  respiration; 
and  if  such  be  the  case,  it  would  show  that  in 
this  animal  a  great  extent  and  variety  of  parts 
are  concerned  in  that  function.  The  ciliary 
motion  on  the  inner  surface  of  the  stomach  and 
coeca  is  probably  subservient  also  to  the  process 
of  digestion.  It  is  conceivable  that  by  means 
of  this  provision  the  dissolved  or  digested  food 
might  be  introduced  into  the  coeca,  and  spread 
over  their  internal  surface,  there  to  be  duly 
mixed  with  secreted  fluidsjand  subjected  to 
the  process  of  absorption ;  the  returning  cur- 
rent serving  to  bring  back  the  residue,  or  to 
convey  secreted  fluids  into  the  stomach.  Or, 
considered  as  subservient  to  respiration,  the  cili- 
ary motion,  in  diffusing  the  digested  food  over 
the  internal  surface  of  the  coeca,  may  at  the 
same  time  expose  it  to  the  respiratory  influence 
of  the  water  on  their  outside. 

These  phenomena  in  the  Asterias  seem  not  to 
have  been  previously  noticed.  Tiedemann,*  it 
is  true,  had  observed  an  eddying  motion  of  the 
water  in  the  vicinity  of  the  respiratory  tubes 
while  the  animal  was  slowly  distending  or 
emptying  itself,  but  he  conceived  it  to  be 
nothing  more  than  the  commotion  necessarily 
produced  by  the  passage  of  the  water  through 
the  tubes.  There  can  be  little  doubt  that  the 

*  Anat.  der  Rohren  Holothurie,  etc.  p.  40. 


CILIA. 


617 


phenomenon  he  saw  was  caused  by  the  ciliary 
motion  on  the  external  surface,  though  he  was 
not  aware  of  this. 

Having  entered  into  these  details  respecting 
the  Asterias,  I  may  describe  more  briefly  the 
phenomena  in  the  Sea-urchin,  the  more  so  as 
my  opportunities  of  observing  this  animal  have 
been  less  frequent. 

The  species  submitted  to  examination  was 
the  common  large  Sea-urchin  of  our  shores, 
Echinus  esculentus,  described  by  Monro.* 
Its  body  consists  of  a  globular  shell,  containing 
the  viscera.  The  mouth  is  placed  underneath, 
the  anus  opposite  on  the  upper  surface.  The 
tubular  feet  are  disposed  in  vertical  rows  from 
the  mouth  to  the  anus,  the  intermediate  part  of 
the  shell  being  covered  with  moveable  spines, 
and  the  singular  claw-like  organs  referred  to  in 
describing  the  Asterias.  As  in  the  Asterias, 
there  are  membranous  respiratory  tubes,  but 
they  are  comparatively  few  in  number,  forming 
ten  small  bunches  or  groups,  which  are  placed  on 
the  under  surface  not  far  from  the  mouth,  and 
open  internally  in  ten  small  perforated  pits,  like 
those  of  the  Asterias;  they  are  supposed  by 
Tiedemann  and  others  to  be  the  channels  by 
which  the  sea-water  gets  into  the  interior  of  the 
body,  and  fills  the  space  between  the  inside  of 
the  shell  and  the  contained  viscera.  The  ali- 
mentary canal,  commencing  at  the  mouth,  rises 
through  the  curious  dental  apparatus  named 
Aristotle's  lantern,  turns  in  a  waving  manner 
twice  round  the  inside  of  the  shell,  and  termi- 
nates above  at  the  anus  ;  it  is  supported  by  a 
mesentery  derived  from  a  membrane  which  lines 
the  cavity  of  the  shell,  and  which  is  reflected 
over  its  contents  like  a  peritoneum.  Inside  the 
shell  we  also  find  the  ovaries  and  the  rows  of 
feet.  The  internal  parts  of  the  latter,  instead  of 
being  round  vesicles  as  in  the  Asterias,  are  broad 
laminae  enclosing  vessels,f  canals  or  branched 
cavities,  which  canals,  like  the  vesicles  of  the 
Asterias,  communicate  on  the  one  hand  with 
the  tubes  of  the  feet,  and  on  the  other  with  a 
common  vessel  which  runs  along  the  middle  of 
each  double  row  of  laminae.  The  vessels  or 
spaces  within  the  laminae  are  much  branched ; 
they  form  a  plexus  surrounded  by  a  principal 
vessel  at  the  border. 

I  have  found  the  ciliary  motion  over  nearly 
the  whole  surface  of  the  cavity  of  the  body  and 
the  contained  parts,  which  surface,  as  mentioned 
already,  is  covered  by  a  lining  membrane  or 
peritoneum.  Two  longitudinal  currents  run  on 
the  intestine  in  the  same  direction,  viz.  one 
along  the  line  of  attachment  of  the  mesentery, 
the  other  at  the  opposite  part  of  the  tube.  On 
the  remaining  circumference  of  the  intestine 
the  impulsion  is  directed  obliquely  towards  the 
nearest  longitudinal  current.  In  regard  to  the 
laminae  of  the  feet,  a  current  runs  down  the 
middle  of  each  of  the  double  rows,  following 
the  course  of  the  longitudinal  vessel  there 
situated,  the  direction  being  from  the  anus  to- 
wards the  mouth.  Lateral  currents  pass  over 
the  surface  of  the  laminae  from  their  external 


*  Anatomy  of  Fishfs,  &c. 
t  Accurately  described  by  Monro,  1.  c. 
VOL.  I. 


to  their  internal  border,  where  they  join  the 
middle  current;  they  follow  the  irregular  eleva- 
tions on  the  surface  of  the  lamina?  occasioned 
by  the  canals  or  vessels  in  the  latter;  hence, 
when  charcoal  powder  is  applied,  the  particles 
follow  winding  paths  in  crossing  from  one  edge 
of  the  laminae  to  the  other,  and  they  are  fre- 
quently caught  in  a  hollow  between  two  cur- 
rents, and  whirled  about  for  some  time  before 
they  resume  their  way.  Currents  were  visible 
also  on  the  reflections  of  the  lining  membranes 
which  cover  and  pass  between  different  parts  of 
the  lantern,  and  at  the  internal  openings  of  the 
respiratory  tubes.  The  cilia  on  the  parts  de- 
scribed are  excessively  small,  but  distinctly  per- 
ceptible. The  ciliary  motion  was  not  detected 
on  the  external  surface  of  the  body  nor  within 
the  alimentary  canal;  but  in  regard  to  these 
parts  the  observations  could  scarcely  be  consi- 
dered as  conclusive;  nor  could  1  determine  whe- 
ther, as  in  the  Asterias,  the  phenomenon  occurs 
within  the  feet  or  within  the  spaces  or  vessels 
of  their  membranous  laminae,  though  from  an 
observation  of  Carus,  who  states  that  he  saw 
globules  circulating  within  these  laminae,  its 
existence  in  that  situation  is  not  improbable.* 

This  provision  in  the  Echinus  is  probably,  as 
in  the  analogous  cases  already  described,  chiefly 
subservient  to  respiration.  Tiedemann,  who 
ascribed  a  respiratory  office  to  the  water  within 
the  animal,  expresses  himself  at  a  loss  to  con- 
ceive by  what  mechanism  it  can  be  made  to 
enter  and  issue  from  a  cavity  with  unyielding 
sides  incapable  of  being  expanded  and  con- 
tracted by  muscular  action ;  perhaps  the  provi- 
sion here  described  may  be  adequate  for  this 
purpose.  Since  the  above  observations  were 
made,  a  fact  has  been  mentioned  by  Ehrenberg,f 
from  which  it  appears  that  the  ciliary  motion 
exists  on  the  external  surface  of  the  Echinus  on 
the  spines.  The  species  observed  by  him  was 
the  Echinus  sexatilis.  The  observations  of  Carus 
and  Ehrenberg  here  referred  to  comprehend 
the  only  facts  hitherto  published  on  the  ciliary 
motions  of  the  Echinus  which  have  come 
under  my  notice. 

7.  Annelida. — In  proceeding  to  describe  the 
ciliary  motion  in  animals  of  this  class,  in 
several  of  which  it  occurs,  it  seems  advisable 
to  begin  with  the  Aphrodita,  as  the  phenomena 
in  this  animal  present  a  remarkable  analogy 
with  those  we  have  been  considering  in  the 
Echinodermata. 

A  great  part  of  the  body  of  the  Aphrodita 
aculcata,  or  Sea-mouse,  (of  which  Jig.  299,  A, 
represents  a  cross  section,)  is  occupied  by  the 
abdominal  cavity,  (a,  a,  a.)  Along  the  superior 
wall  of  this  cavity  a  row  of  cells  (b)  is  placed 
on  each  side,  which  below  open  into  the  abdo- 
men, but  above,  or  exteriorly,  project  on  the 
dorsal  surface  as  oblong  transverse  eminences. 
Each  alternate  cell  on  the  back  bears  a  broad 
membranous  scale  (c,  c),  and  each  of  the  in- 
termediate ones  a  small  indented  process.  On 
the  back  a  covering  of  felt-like  substance  (d) 
is  stretched  from  side  to  side  like  a  roof  over 

*  Analecten  zur  Natur-vrifwenschaft,  etc.  Dres- 
den, 1829,  p.  152. 

t  Muller's  Archiv.  Band  1,  p.  578. 

2  s 


018 


CILIA. 


Fig.  299. 


A.  Cross  section  of  the  Aphrodita  aculeata. 


B.  Alimentary  canal  and  c&ca,  seen  from  above. 

the  cells  and  scales,  inclosing  them  in  a  space 
(e)  to  which  the  water  has  free  access.  Re- 
turning to  the  abdomen,  we  find  the  nearly 
straight  alimentary  canal,  its  anterior  third 
Cft  fig-  B)  forming  the  stomach,  the  remaining 
part  or  intestine  fg,  fig.  A  and  B)  being  fur- 
nished on  each  side  with  a  number  of  long 
creca  Ch),  whose  branched  extremities  (i,  i) 
are  in  part  lodged  in  the  before-mentioned 
cells.  The  abdomen  is  lined  with  a  de- 
licate peritoneal  membrane,  which  also  lines 
the  cells,  and  is  reflected  over  the  viscera. 

In  the  living  Aphrodita  the  water  freely 
enters  and  issues  from  the  space  (e)  beneath 
the  felty  membrane,  passing  over  the  external 
surface  of  the  cells  and  their  appendages.  The 
flow  of  the  water  in  this  passage  is  produced, 
as  I  have  repeatedly  observed,  by  the  elevation 
and  depression  of  the  scales,  and  on  no  part 
of  the  surface  over  which  the  fluid  passes  is 
the  ciliary  motion  to  be  observed.  But  the 
water  also  enters  the  cavity  of  the  abdomen, 
though  it  is  doubtful  by  what  orifices  this  takes 
place,  for  my  endeavours  to  find  those  de- 


scribed by  Treviranus*  in  the  alternate  in- 
tervals of  the  feet  have  never  been  successful. 
In  whatever  way  it  may  happen,  however, 
there  can  be  no  doubt  of  the  fact  that  the 
water  enters  the  abdomen,  and  consequently 
fills  the  dorsal  cells  and  surrounds  the  intestine 
and  its  cceca,  which  last  organs,  according  to 
Sir  Everard  Home  and  Treviranus,  exercise  a 
respiratory  function,  an  opinion  which  derives 
additional  probability  in  considering  the  phe- 
nomena of  the  ciliary  motion  to  be  here  de- 
scribed. The  ciliary  motion  exists  in  two 
situations,  1st,  on  the  external  surface  of  the 
intestine  and  cceca  and  the  internal  surface  of 
the  cells,  which  surfaces  are  in  contact  with 
the  contained  water ;  2dly,  within  the  intes- 
tine and  cceca,  or  on  their  internal  surface.  The 
motion  as  usual  persists  for  some  time  in  de- 
tached parts,  and  the  direction  of  the  currents 
is  constant.  On  the  intestine  the  currents  pass 
from  the  inferior  surface  round  the  sides  to  the 
upper  part  (as  marked  by  the  arrows).  On 
the  cceca  the  direction  is  outwards  or  towards 
the  cells,  and  the  motion  is  very  distinct  at 
their  extremities.  The  direction  on  the  inner 
surface  of  the  cells  was  not  completely  made 
out,  but  it  seemed  to  be  chiefly  downwards. 
Nor  was  the  direction  of  the  impulsion  satis- 
factorily ascertained  on  the  internal  surface 
of  the  intestine  and  cceca,  though  of  the  ex- 
istence of  the  phenomenon  in  that  situation 
there  could  be  no  doubt. 

From  what  has  been  stated,  it  appears  then, 
first,  that  in  the  Aphrodita  the  water  finds 
access  to  the  outside  of  the  cells,  over  which 
it  is  conveyed  by  the  elevation  and  depression 
of  the  dorsal  scales,  and  to  the  inside  of  the 
cells,  over  which,  as  well  as  over  the  external 
surface  of  the  intestine  and  its  coecal  appen- 
dages, it  is  moved  by  the  action  of  cilia.  In 
both  situations  the  motion  of  the  fluid  is  pro- 
bably subservient  to  the  respiratory  function, 
and  if  it  really  be  so,  we  must  reckon  the 
scales,  the  cells,  the  alimentary  canal,  and  its 
appendages,  as  constituting  the  respiratory  ap- 
paratus. Secondly,  that  the  ciliary  motion 
exists  also  on  the  internal  surface  of  the  in- 
testine and  cceca,  where  it  is  likely  connected 
both  with  respiration  and  digestion.  In  all 
this  we  cannot  overlook  the  analogy  which 
subsists  between  the  Aphrodita  and  Asterias. 
In  both  the  water  is  conveyed,  though  by  a 
different  mechanism,  over  the  external  surface 
of  the  body ;  in  both  it  enters  the  cavity  con- 
taining the  viscera ;  in  both  it  is  moved  along 
the  parietes  of  the  cavity  and  surface  of  the 
viscera  in  a  determinate  direction  by  the 
agency  of  cilia ;  and,  lastly,  in  both  the  ciliary 
motion  occurs  on  the  internal  surface  of  the 
digestive  organs. 

I  first  observed  the  ciliary  motions  in  the 
Aphrodita  aculeata  in  1830,  at  the  same  time 
with  the  late  Mr.  Cheek,  who  gave  notice 
of  the  fact  in  the  journal  of  which  he  was 
conductor  ;f  but  most  of  the  observations  on 

*  Zeitschrift  fur  Physiologic,  Band  iii.  p.  158. 
t  Edin.  Jour,  of  Nat.  and  Geog.  Science,  April, 
1831,  p.  246. 


CILIA. 


019 


which  the  preceding  account  is  founded,  were 
made  more  recently.  There  is  no  mention  of 
the  existence  of  the  phenomenon  in  the  Aphro- 
dita  to  be  found  in  systematic  works  on  com- 
parative anatomy,  nor  in  any  of  the  special 
memoirs  on  that  animal  which  I  have  had  an 
opportunity  of  consulting. 

The  ciliary  motion  exists  in  several  other 
animals  belonging  to  the  class  Annelida.  It 
is  remarkably  distinct,  and  easily  observed,  on 
the  branchiae  or  gills  of  the  Serpula.  These 
organs  consist  of  two  bunches  of  pinnated  or 
feather-like  processes,  which  the  animal  pushes 
forth  from  the  calcareous  tube  in  which  it  lives, 
and  spreads  out  in  a  radiating  form.  The 
edges  of  the  branchiae,  both  of  the  stems  and 
of  the  leaflets,  are  fringed  with  cilia,  which 
exhibit  their  vibrating  and  undulating  motions, 
and  cause  a  constant  current  of  water  over  the 
surface  of  the  gills,  serving  here,  no  doubt,  as 
in  analogous  instances,  at  least  chiefly  for 
respiration. 

In  a  paper  already  referred  to,*  I  mentioned 
having  observed  the  phenomena  in  question  in 
the  Amphitrite.  The  animal  meant  was  a  com- 
mon marine  tubicolar  worm  (fig.  300),  which 

Fig,  300. 


Amphitrite  alveolata. 

A.  Dorsal  surface,  natural  size. 

B.  Part  before  a,  b,  magnified. 

C.  A  gill  magnified. 

D.  One  still  more  magnified,  to  show  the  spiral 

ridges  and  cilia.  ' 

appeared  to  be  the  same  with  that  figured  by 
Ellis  (Corall.  plate  36),  and  described  by  Cuvier 
as  the  Amphitrite  a  ruche,  with  which  figure  it 
agrees,  except  that  it  bears  two  rows  of  simple 
filaments  on  the  back,  which,  for  reasons  that 
will  appear,  I  was  led  to  regard  as  gills.  But 
if  these  are  really  gills,  the  animal  must,  it 
seems,  be  arranged  with  the  Dorsibranchiata, 
probably  as  a  Sabella.  The  currents  in  this 
worm  proceed  forwards  along  the  back,  be- 
tween the  rows  of  gills  (as  marked  in  Jig.  B), 
and  along  the  gills  themselves  (see  C),  whose 
points  are  directed  forwards.  The  conical  fila- 
ment of  which  each  gill  consists  is  marked  on 
one  side  by  ridges  (see  C,  D),  crossing  it 
obliquely  like  segments  of  a  spiral;  and  on 
these  ridges  as  well  as  on  the  point  of  the  gill 
the  most  conspicuous  cilia  are  placed.  The 
cilia  are  comparatively  large  and  curved, 
their  points  being  turned  towards  the  summit 
of  the  gill,  which  figure  they  retain  when  their 
motion  is  stopped.  The  gills  contain  large 

*  Edin.  Med.  and  Sur.  Jour.  vol.  xxxiv. 


bloodvessels,  which  when  distended  give  them 
a  bright  red  colour. 

The  ciliary  motion  occurs  also  on  what  seem 
to  be  the  branchiae  of  another  tubicolar  worm, 
the  name  of  which  is  unknown  to  me;  the 
organs  in  question  are  placed  at  the  anterior 
extremity  of  the  animal,  concealed  by  a  pro- 
fusion of  long  serpentine  tentacula. 

Lastly,  Mr.  Cheek*  observed  the  ciliary 
motion  in  the  Sandworm  (Arenicola  piscato- 
ruin).  It  was  seen  on  the  inner  surface  of  the 
internal  vesicles,  which  Sir  Everard  Home  de- 
scribes as  livers.  Nothing  similar  exists  on  the 
tufts  of  filaments  which  form  the  gills.f 

8.  Mollusca. —  The  ciliary  motion  prevails 
very  extensively  in  this  division  of  the  animal 
kingdom.  It  seems  to  exist  generally  in  the 
Gasteropodous  and  Acephalous  Mollusca. 
There  is  some  uncertainty  as  to  its  existence 
in  the  Cephalopoda ;  I  have  repeatedly  sought 
for  it  in  that  class,  but  without  success. 

It  occurs  on  the  surface  of  the  respiratory 
organs,  and  often  on  other  surfaces  over  which 
the  water  has  to  pass  in  the  act  of  respiration. 
It  also  exists  within  the  alimentary  canal,  at 
least  this  has  been  ascertained  in  several  spe- 
cies of  Gasteropoda  and  Acephala,  and  may 
be  presumed  of  the  rest.  Moreover,  in  some 
of  the  Gasteropoda,  it  is  very  manifest  on  the 
horns  or  feelers,  which  suggests  the  possibility 
of  its  aiding  in  these  instances  in  the  exercise 
of  the  sense  of  touch  or  smelling.  In  all 
cases  the  impulsion  maintains  a  determinate 
direction,  which  continues  the  same  in  parts 
detached  from  the  animal.  In  salt-water  spe- 
cies, the  action  of  the  cilia  and  impulsion  of 
the  fluid,  are  instantly  stopped  by  putting  the 
parts  into  fresh  water. 

The  ciliary  motion  also  occurs  in  the  embryo 
of  the  Mollusca  within  the  egg,  which  pheno- 
menon will  be  considered  in  the  next  section. 

A.  Gasteropodous  Mollusca. — Of  this  class 
the  phenomena  have  been  observed  by  myself 
and  others  in  the  orders  of  Nudibranchiata, 
Cyclobranchiata,  Pectinibranchiata,  and  the 
aquatic  PulmoniJ'era,  in  one  or  more  species 
of  each. 

a.  Nudibranchiata. — In  this  order,  in  which 
the  gills  are  entirely  exposed,  the  currents  can 
be  very  easily  observed.  The  Doris,  a  species 
of  which  is  represented  in  the  adjoining  figure 
(301),  may  serve  as  an  example.  The  arbo- 
rescent gills  («,  «)  are  ranged  in  a  circle  round 
the  anus,  and  their  stems  and  branches  are 
covered  with  cilia.  Currents  pass  over  their 
surface,  the  general  direction  being  towards 
the  points;  small  portions  detached  still  ex- 
cite currents  in  the  same  direction,  and,  if  free, 
move  through  the  water  in  the  opposite  one. 
I  have  examined  three  species  of  Doris,  and 

*  Edin.  Journ.  of  Nat.  and  Geog.  Science, 
April,  1831,  p.  245. 

t  The  ciliary  motion  has  also  been  observed  in 
Planariae,  on  the  surface  of  the  body,  by  Gruit- 
huisen,  (Salzb.  Med.  Chir.  Zeit.  1818,  vol.  iv.) 
and  by  Purkinje  and  Valentin  Gruithuisen  also 
discovered  it  in  the  Nais  proboscidea,  in  the  pos- 
terior part  of  the  intestine,  (Nov.  Act.  Acad.  Caes. 
Leop.  xi.  p.  238.) 

2  S   2 


620 


CILIA. 


in  one  of  them,  the  D.  cornuta,  the  ciliary 
motion  was  very  strong  on  the  club-shaped 
feelers;  perhaps  it  may  be  the  same  in  all. 
I  also  examined  the  Tritonia  and  Eolis  belong- 
ing to  this  order,  and  found  the  ciliary  motion 
in  corresponding  parts. 

b.  Cyclobranchiata. —  In  the  Patella  or 
Limpet  (fg.  302,  representing  the  under 
surface),  the  gills  form  a  series  of  simple 

Fig.  302. 


on  each  side  of  it,  Fig.  303. 

diminishing  in  size 

as  they  approach  its 

point.  The  currents 

on  each  of  the  gills 

are  directed  towards 

its  apex,   and  also 

pass   between    the 

secondary    laminae 

over  their    surface 

and     along      their 

edges :  a,  a,  are  the 

gills  ;  b  one  of  the 

gills        magnified, 

showing  its  laminae ;  Chiton. 

c  the  same  viewed 

endwise.    The  arrows  mark  the  direction  of 

the  currents. 

c.  Pectinibranchiata. —  The  common  Buc- 
cinum  (Jig.  304)  may  serve  as  an  example  of 

Fig.  304. 


Patella. 

B.  Portion  inclosed  between  the  lines  c  and  d, 
magnified  to  show  a,  a,  the  branchial  la- 
minae, and  b,  b,  the  circular  border  of  the 
mantle. 

laminae  (#,  a)  attached  within  the  circular 
border  of  the  mantle  (b,  b}.  The  currents  pass 
inwards  from  the  edge  of  the  mantle  to  the 
gills,  then  over  the  surface  and  along  the  border 
of  each  branchial  lamina,  from  its  outer  or 
lower  to  its  inner  or  upper  edge,  as  indicated 
in  the  figure  by  the  arrows.  In  the  Limpet 
the  ciliary  motion  is  also  found  on  the  inner 
surface  of  the  alimentary  canal. 

In  the  Chiton  or  Oscabrion  (Jig.  303),  the 
only  other  genus  of  this  order,  the  gills  are 
situated  as  in  the  Limpet,  but  are  of  a  more 
complex  structure.  Each  consists  (at  least  in 
the  species  examined  by  me)  of  a  triangular 
lamina,  with  a  series  of  smaller  laminae  set 


Buccinum  Undatum. 

this  order.  The  gills,  as  accurately  described 
by  Cuvier,  are  attached  to  the  roof  of  a  bran- 
chial cavity  or  recess  formed  between  the  man- 
tle («,  a)  and  upper  part  of  the  body  (6)  in  the 
last  turn  of  the  shell,  and  opening  anteriorly 
by  a  broad  slit.  At  the  left  end  of  the  slit  the 
edge  of  the  mantle  is  prolonged  in  the  form 
of  a  groove  (c),  which  prolongation  is  called 
the  syphon,  and  is  lodged  in  a  corresponding 
groove  of  the  shell.  On  detaching  the  roof 
of  the  branchial  cavity  at  the  left  side,  and 
reflecting  it  (as  represented  in  the  figure),  we 
find  attached  to  it,  first,  the  gills,  consisting 
of  a  short  double  row  (d)  and  a  longer  single 
row  (e)  of  laminae,  the  latter  being  larger ; 
secondly,  to  the  right  of  the  gills,  the  so-named 
mucous  laminae  (/,./);  thirdly,  still  more  to 
the  right,  the  rectum  (g). 

The  water  enters  by  the  syphon,  and  issues 
at  the  right  extremity  of  the  branchial  slit. 
The  ciliary  motion  and  currents  take  place  on 
the  gills,  mucous  laminae,  and  rectum,  and  on 


CILIA. 


621 


the  inner  surface  of  the  mantle,  where  it  forms 
the  roof  of  the  branchial  cavity.  Their  situ- 
ation and  direction  are  indicated  in  the  figures 
by  the  arrows.  B  is  an  enlarged  view  of  a 
few  laminae  from  the  larger  series,  h  the  at- 
tached border,  i  point,  m  left,  and  n  right 
border.  Currents  pass  between  these  laminae 
along  the  surface  and  border  of  each,  as 
shewn  in  B ;  C  is  a  magnified  view  of  the 
laminae  of  the  smaller  set,  on  which  the  di- 


rection of  the  currents  is  marked ;  the  direc- 
tion on  other  parts  will  be  understood  by  re- 
ferring to  figure  A. 

The  ciliary  motion  is  very  manifest  within 
the  alimentary  canal,  in  the  gullet,  stomach, 
and  intestine;  the  direction  of  impulsion  is 
from  the  mouth  towards  the  anus. 

The  ciliary  motion  has  been  observed  by 
myself  and  others  in  the  Paludina  vivipara, 
a  fresh-water  snail  belonging  to  this  order, 


Fig.  305.  A 


Mytilus  Edulis. 

F.   Portion  of  a  bar  of  the  ijill, 
the  cilia,  highly  magnified. 


with 


in  which  also  Purkinje  and  Valentin  state 
that  they  observed  it  within  the  alimentary 
canal;  and  Gruithuisen*  has  described 
the  phenomenon  as  seen  on  the  branchiae 
of  another  fresh-water  snail,  which  he 
names  Valvata  branchiata.  He  saw  moving 
cilia,  which  caused  an  incessant  agitation 
in  the  water;  but  he  does  not  state  whether 
the  motion  followed  any  constant  direc- 
tion, although  we  may  infer  that  this  was 
the  case.  He  rightly  attributed  to  these 
motions  a  respiratory  function,  but  seems 
not  to  have  observed  that  similar  pheno- 
mena existed  in  other  Mollusca. 

d.  Pulmonifcra.  The  ciliary  motion  is 
not  confined  to  those  Mollusca  which 
breathe  by  gills,  for  it  occurs  also  in  the 
Lymnaea  and  Planorbis,  which,  though 
they  live  in  water,  breathe  air  by  a  pul- 
monary sac.  In  these  instances  the  impulsion  of  the  water 
takes  place  on  the  surface  of  the  tentacula,  which  is  covered 
with  cilia.  If  these  parts  are  to  be  regarded  as  organs  of 
sensation  alone,  the  ciliary  motion  observed  upon  them, 
as  well  as  that  which  occurs  on  the  tentacula  of  bran- 
chiferous  species,  must  be  considered  as  connected  with 
the  function  of  sensation;  but  the  tentacula,  which  in  the 
Lymnaea  are  broad  vascular  laminae,  might  be  conceived 
also  to  perform  the  office  of  accessory  organs  of  respiration, 
in  which  case  the  pulmoniferous  Mollusca  here  mentioned 
would  possess  organs  both  of  aerial  and  aquatic  respiration. 
In  the  Lymnaea  the  motion  has  also  been  observed  by 
Purkinje  and  Valentin  within  the  alimentary  canal. 

B.  Conchiferous  AcephfJa. — The  motion  in  question  has 
been  found  in  several  bivalve  Mollusca,  both  of  salt  and 
fresh  water,  and  there  can  be  little  doubt  that  it  exists  in  all. 
The  common  Sea-mussel  (Jig.  305)  will  serve  as  an 
example  of  the  class.  It  will  be  recollected  that  the 
gills  of  this  animal  (Jig.  A,  r,  c',  d,)  have  the  form  of 

*  Nova  Acta  Acad.  Caes.  Lcop.  x.  p.  437. 


622 


CILIA. 


leaves,  there  being  two  on  each  side  inclosed 
between  the  lobes  of  the  mantle  (a,  a,  a', 
a").  Between  the  gills  are  interposed  what 
is  called  the  foot  (f)  arid  the  prominent  part 
of  the  abdomen,  which  separates  the  two 
of  the  right  side  from  those  of  the  left. 
Each  gill  or  leaf  consists  of  two  layers,  which 
are  made  up  of  vessels  set  very  close  to  one 
another  (fig.  D,)  like  the  teeth  of  a  comb,  or 
like  parallel  bars,  across  the  direction  of  the 
gill,  and  perpendicular  to  the  great  vascular 
trunks  running  along  its  base,  with  which  they 
communicate.  The  two  layers  composing  each 
gill  are  connected  together  at  its  edge,  and  by 
a  few  points  of  their  contiguous  surfaces.  At 
the  base  only  one  layer  is  fixed,  the  other  ter- 
minating at  this  part  by  a  thick  unattached 
border  (e,  e),  under  which  a  probe  may  be 
passed  into  the  interior  space  between  the  two 
layers.  This  is  further  explained  by  Jig.  B, 
which  represents  a  section  of  the  two  gills  of 
one  side  cut  parallel  to  the  bars.  The  layers 
(e  c,fc,}  are  united  at  the  edge  of  the  gill  (c), 
but  separated  at  the  base,  the  one  being  fixed 
at  J'9  the  other  ending  by  a  free  margin,  e. 
g,  g,  is  the  space  between  the  layers ;  it  com- 
municates with  the  excretory  orifice  (h,Jig.  A). 
Fig.  C  shews  the  upper  part  of  the  gill, 
(c,  h,  Jig.  B,)  viewed  similarly,  but  magnified 
eighteen  diameters.  Two  bars,  (e  c,f  c,)  be- 
longing to  opposite  layers,  are  seen ;  they  are 
shaped  somewhat  like  the  blade  of  a  knife, 
with  a  thick  round  external  border  (e),  and  a 
thin  internal  edge  (A)  opposed  to  the  corres- 
ponding one  of  the  other  layer,  with  which  it 
is  connected  at  a  few  places  by  cross  slips, 
a,  i,  Jig.  C,  and  k,  k,  Jig.  B,  where  they  are 
longer,  the  space  at  this  part  being  wider. 
Fig.  D  is  a  small  portion  of  one  of  the  layers, 
(£>  ^  'fig'  A*)  magnified  eighteen  diameters. 
The  bars  are  connected  laterally  with  the  adja- 
cent ones  of  the  same  layer  at  short  intervals, 
by  round  projections  on  their  sides,  («,  a,  a,  a, 
in  Jigs.  D,  C,  and  E,)  in  which  last  they  are 
still  more  magnified.  Each  of  these  projec- 
tions adheres  but  slightly  to  the  corresponding 
one  of  the  collateral  bar,  and  its  surface  is 
covered  with  small  filaments  resembling  the 
cilia  in  the  other  parts,  only  their  motion  is  very 
slow.  Besides  the  gills,  the  mussel  has  four 
triangular  laminae  (m,  w,  n,  Jig.  A,)  placed 
round  the  mouth,  which  probably  serve  for 
respiration ;  they  have  been  named  labial  ap- 
pendages, tentacula,  or  accessory  gills. 

When  a  live  mussel  is  placed  in  a  vessel  of 
salt  water,  it  is  soon  observed  to  open  slightly 
the  two  valves  of  its  shell,  and  at  the  same 
time  a  commotion  is  evident  in  the  water  in  its 
vicinity.  This  is  occasioned  by  the  water  en- 
tering at  the  posterior  or  large  end  of  the 
animal  into  the  space  between  the  lobes  of  the 
mantle  in  which  the  gills  are  lodged,  and  issuing 
near  the  same  place  by  a  separate  orifice  in  a 
continued  stream,  as  represented  by  the  arrows, 
(g  and  A,  Jig.  A),  g  being  the  entering  and  h 
the  issuing  stream.  The  existence  of  this  con- 
tinuous current  is  well  known,  but  the  agency 
by  which  the  water  is  set  in  motion  appears  not 
to  have  been,  at  least  generally,  understood.  It 


can  readily  be  shewn  that  here,  as  in  the  in- 
stances already  described,  the  water  receives  its 
impulse  from  the  ciliated  snrface  of  the  gills 
and  other  parts  over  which  it  passes,  and  that 
it  is  carried  along  these  surfaces  in  a  determi- 
nate direction.  The  whole  surface  of  the  gills 
and  labial  appendages  or  accessory  gills,  the 
inner  surface  of  the  cloak,  and  the  surface  of 
some  other  parts  produce  this  effect,  and  the 
combined  action  of  the  cilia  over  this  extensive 
surface  gives  rise  to  the  main  current  which 
enters  and  issues  from  the  animal. 

On  removing  one  of  the  valves,  turning  down 
the  cloak,  as  represented  at  o,  and  putting 
moistened  charcoal  powder  on  the  surface  of 
the  gills,  the  finer  part  of  the  powder  soon  dis- 
appears, having  penetrated  through  the  inter- 
stices of  the  bars  or  vessels  into  the  space 
between  the  two  layers  of  the  gill.  On  arriving 
there  a  part  is  often  forced  out  again  from 
under  the  border  of  the  unattached  layer  at  the 
base  of  the  gill,  but  most  of  it  is  conveyed 
rapidly  backwards  between  the  two  layers,  and 
is  carried  out  at  the  excretory  orifice  with  the 
general  current,  its  course  being  indicated  by 
the  dotted  arrows  in  the  figure.  The  coarser 
particles  remain  outside  the  gill,  and  are  slowly 
carried  to  its  edge,  following  the  direction  of 
the  bars  ;  they  then  advance  along  the  edge  of 
the  gill  towards  the  forepart  of  the  animal,  as 
shewn  by  the  entire  arrows.  It  thus  appears 
that  the  water  first  passes  in  between  the 
lobes  of  the  mantle  to  the  external  surface  o . 
the  gills;  it  is  then  forced  into  the  space 
inclosed  between  their  layers,  from  whence  it 
is  driven  out  at  the  excretory  orifice,  to  which 
the  inclosed  spaces  of  all  the  gills  lead.  As 
this  process  continues  to  go  on  after  the  shell 
and  lobe  of  the  mantle  of  one  side  are  removed, 
it  is  evident  that  the  motion  of  the  water  must 
be  mainly  produced  by  the  cilia  of  the  gills,  to 
be  immediately  described.  By  their  agency 
the  fluid  is  forced  into  the  space  within  the 
gills,  and  this  operation  taking  place  over 
the  whole  extent  of  the  gills,  must,  by  its 
concentrated  effect,  give  rise  to  a  powerful 
issuing  stream  at  the  excretory  orifice,  of  which 
the  entering  stream  seems  to  be  a  necessary 
result. 

The  cilia  are  found  on  the  gills,  the  acces- 
sory gills,  the  inside  of  the  mantle,  and  the 
foot.  Only  those  on  the  gills  require  particular 
notice.  Most  of  them  are  arranged  along  the 
sides  of  the  vessels  or  bars  («,  a,  Jig.  F),  com- 
posing the  gills,  in  two  sets,  one  nearer  the 
surface  consisting  of  longer  and  more  opaque 
cilia,  (6,  &,)  the  other  close  to  the  first,  but  a 
little  deeper,  and  consisting  of  somewhat  shorter 
and  nearly  transparent  cilia,  (c,  c.)  Both  sets 
are  in  constant  motion,  but  of  this  it  is  difficult 
to  convey  a  correct  idea  by  description.  The 
more  opaque  cilia,  or  those  of  the  exterior 
vange,  appear  and  disappear  by  turns,  as  if  they 
were  continually  changing  from  a  horizontal  to 
a  vertical*  direction  and  back  again.  The 

*  By  vertical  is  here  meant  a  direction  perpendi- 
cular to  the  plane  of  the  gills,  which  direction  is 
vertical  when  the  gills  are  spread  out  under  the 
microscope. 


CILIA. 


623 


motion  of  the  other  set  consists  in  a  succession 
of  undulations,  which  proceed  in  a  uniform 
manner  along  the  sides  of  the  bar  from  one 
end  to  the  other.  It  might  be  very  easily 
mistaken  for  the  circulation  of  globules  of  a 
fluid  within  a  canal,  more  especially  as  the 
course  of  the  undulations  is  different  on  the 
two  sides  of  the  bar,  being  directed  on  one 
side  towards  the  edge  of  the  gill,  and  on  the 
other  towards  the  base.  But  besides  that  the 
undulations  continue  for  some  time  in  small 
pieces  cut  off  from  the  gill,  which  is  incon- 
sistent with  the  progression  of  fluid  in  a  canal, 
the  cilia  are  easily  distinguished  when  the  un- 
dulatory  motion  becomes  languid.  When  it 
has  entirely  ceased,  they  remain  in  contact  with 
each  other,  so  as  to  present  the  appearance  of 
a  membrane,  (d,  d,  Jig.  F.)  Besides  the  two 
rows  of  cilia  just  described  on  each  side  of  the 
bars,  others  are  placed  in  a  less  regular  manner 
on  their  external  and  internal  borders.  The  in- 
ternal (h,  fig.  C)  are  exceedingly  small ;  they 
extend  upon  the  cross  slips,  (i,jig.  C).  Those 
on  the  external  borders  are  very  numerous  and 
thick-set,  and  of  considerable  size,  especially 
on  the  extremity  of  the  bar  at  the  edge  of  the 
gill  (c,  Jig.  C) ;  their  points  are  directed  to- 
wards the  edge  of  the  gill.  It  is  probably  by 
the  agency  of  these  last-mentioned  cilia  that 
the  particles  of  food  or  other  foreign  matter 
are  conveyed  along  the  surface  of  the  gill  to 
its  edge,  and  then  onwards  to  the  mouth, 
while  the  others  may  serve  principally  to  force 
the  water  through  the  interstices  of  the  bars 
into  the  space  inclosed  between  the  layers, 
and  from  thence  out  at  the  excretory  orifice. 

As  in  other  instances,  detached  portions  of 
the  ciliated  parts  excite  currents  in  the  same 
direction  as  before  their  separation,  or  swim 
through  the  water  in  the  opposite  direction. 
It  is  very  remarkable  that  when  the  parts  are 
immersed  in  fresh  water,  the  currents  and  mo- 
tion of  the  cilia  are  almost  instantaneously 
stopped. 

The  ciliary  motion  is  equally  apparent  on 
the  respiratory  organs  of  the  Oyster,  River-mus- 
sel, and  other  bivalve  Mollusca  which  have 
been  submitted  to  examination.  Purkinje  and 
Valentin  pointed  out  its  existence  also  in  the 
alimentary  canal  of  the  River-mussel,  which 
observation  I  have  confirmed,  and  I  have  found 
the  same  to  be  true  of  the  Sea-mussel.  The 
impulsion  appeared  to  me  in  both  instances  to 
be  chiefly  directed  onwards,  that  is,  towards 
the  anus. 

c.  Tunicata  (Asciditf). — In  the  paper  pre- 
viously referred  to,  I  stated  that  I  had  not  been 
able  to  perceive  the  ciliary  motion  in  the  Ascidia, 
but  added  that  the  observation  seemed  inconclu- 
sive, as  the  specimens  examined  had  been  some 
time  out  of  the  water.  Since  then  I  have  seen 
the  phenomena  as  distinctly  in  the  Ascidiae  as 
in  other  Mollusca.  The  observations  were  made 
on  a  common  species  found  adhering  to  rocks 
in  the  Frith  of  Forth  at  low  water-mark,  and 
as  far  as  they  go  they  agree  with  those  lately 
made  by  Mr.  Lister,*  on  a  small  aggregated 

*  Phil.  Trans.  1834,  p.  378. 


species,  the  substance  of  which  being  nearly 
transparent  enabled  him  to  trace  the  currents 
more  completely.  For  this  reason  it  seems 
preferable  to  borrow  his  description. 

The  annexed    figures    (A  and  B)   represent 


Fig.  306. 


\ 


c  •-- 


one  of  these  Ascidiae  on 
its  peduncle,  with  the 
opening  of  the  mouth  (g) 
and  the  funnel  (/')  in 
front.  The  outer  covering 
is  a  tough  coat  («),  lined 
internally  with  a  soft  sub- 
stance or  mantle  (b).  A 
great  part  of  the  interior 
is  occupied  with  the 
branchial  sac  (c),  whose 
cavity  terminates  upwards 
at  the  oral  opening,  and 
is  closed  at  the  bottom. 
It  is  united  to  the  enve- 
lope or  to  the  mantle 
above  and  behind ;  the 
juncture  (e,  e,)  beginning 
in  front  of  the  oral  open- 
ing, extends  backwards 
on  each  side  of  it,  and  then  downwards  along 
the  middle  of  the  back  (a,  Jig.  A.)  A  vacant 
space  (./',./,)  is  left  between  the  sac  and  mantle 
at  the  sides  and  front,  which  ends  in  the 
opening  of  the  funnel.  The  sac  opens  infe- 
riorly  into  the  oesophagus  (/?),  which  leads  to 
the  stomach  (i),  the  intestine  passing  forwards 
and  opening  by  the  vent  (/c)  into  the  funnel. 
On  its  sides  and  front  the  branchial  sac  is  per- 
forated by  four  rows  of  narrow  vertical  slits  or 
spiracles  (m,  w),  and  through  these  the  water, 
which  flows  constantly  in  at  the  mouth  when 
its  orifice  is  open,  appears  to  be  conveyed  to 
the  vacant  space  (/')  between  the  sac  and 
mantle,  and  it  then  escapes  at  the  funnel. 
The  sac  seems  extremely  thin  between  the 
spiracles,  but  their  edges  are  thickened,  and 
they  are  lined  with  closely  set  cilia,  which,  by 
their  motion,  cause  the  current  of  water.  When 
they  are  in  full  activity,  the  effect  upon  the  eye 
is  that  of  delicately  toothed  oval  wheels,  re- 
volving continually  in  a  direction  ascending  on 


624 


CILIA. 


the  right  and  descending  on  the  left  of  each  oval, 
as  viewed  from  without ;  but  the  cilia  them- 
selves are  very  much  closer  than  the  apparent 
teeth,  and  the  illusion  seems  to  be  caused  by  a 
fanning  motion  given  to  them  in  regular  and 
quick  succession,  which  will  produce  the  ap- 
pearance of  waves,  and  each  wave  answers 
here  to  a  tooth. 

Whatever  little  substances  alive  or  inanimate 
the  current  of  water  brings,  if  not  ejected  as 
unsuitable,  lodge  somewhere  on  the  surface  of 
the  branchial  sac,  along  which  each  particle 
travels  horizontally  with  a  steady  slow  course 
to  the  front  of  the  cavity,  where  it  reaches  a 
downward  stream  of  similar  materials  ( h' )  ; 
and  they  proceed  together,  receiving  accessions 
from  both  sides,  and  enter  at  last,  at  the 
bottom,  the  oesophagus  (h) ;  this  is  a  small 
flattened  tube  which  carries  them,  without  any 
effort  of  swallowing,  towards  the  stomach. 

Mr.  Lister  observed  similar  phenomena  in  a 
species  of  Polyclinum,  another  form  of  com- 
pound Ascidia,  in  which  an  excretory  funnel  is 
common  to  several  individuals.  Mr.  Lister, 
p.  385,  has  adverted  to  the  resemblance  be- 
tween the  Ascidiae  and  a  zoophyte  of  a  similar 
form  to  that  here  described  at  page  610.  I  may 
here  point  out  an  analogy  on  the  other  side,  no 
less  striking,  between  the  Ascidiae  and  bivalve 
Mollusca,  in  regard  to  the  phenomena  now 
under  consideration.  In  both  cases  the  water 
enters  at  one  opening,  and  meeting  with  the 
surface  of  the  membranous  gills,  passes  through 
slits  or  interstices  between  their  vessels  into  a 
space  on  the  other  side  of  the  gill,  which  space 
terminates  at  another  external  opening,  by  which 
the  water  issues.  In  both  cases  also  the  mar- 
gins of  the  slits  in  the  gills  are  fringed  with 
cilia  which  exhibit  a  waving  motion,  the  waves 
proceeding  in  opposite  directions  on  the  two 
borders  of  the  slit.  Lastly,  in  both  cases, 
while  the  water  and  finer  particles  of  matter 
floating  in  it  pass  through  the  slits,  the  coarser 
matters  are  conveyed  along  the  first  surface  of 
the  gills  towards  the  mouth.  The  difference 
lies  chiefly  in  the  nature  and  form  of  the  ex- 
ternal covering  and  the  form  of  the  gills  in 
each;  the  membranous  gills  in  the  mussel 
being  folded  into  double  leaves  on  each  side, 
and  in  the  Ascidia  being  formed  into  a  tubular 
sac ;  the  space  between  the  laminae  of  each 
leaf  in  the  mussel  corresponding  with  the 
space  (f)  enclosed  between  the  branchial  sac 
and  mantle  in  the  Ascidia,  both  these  spaces 
leading  to  the  excretory  orifice. 

The  remarkable  appearances  in  the  Mollusca 
described  above  could  not  wholly  escape  the 
notice  of  naturalists  and  microscopic  observers. 
Thus  we  find  Ant.de  Heide,*  a  Dutch  physician 
of  the  end  of  the  seventeenth  century,  observing 
the  appearance  produced  by  the  ciliary  motion 
in  the  Sea-mussel;  he  names  it  "  motus  radio- 
sus,"  or  "  tremulus."  He  found  it  in  most  parts 
of  the  animal,  but  in  none  more  evident  than  the 
gills  (cirri  pectinati),  in  which  it  is  most  easily 
examined.  "  I  call  the  motion  radiant,"  says 
he,  "  because  it  proceeds  from  the  whole  sur- 

*  Anat.  Mytuli,  &c.    I2mo.     Amst.  1684. 


face  of  the  cirrus  (gill)  almost  in  the  same  way 
as  air-bubbles  issue  from  crabstones  or  metals 
while  undergoing  solution  ;  it  may  be  called 
tremulous,  because  the  parts  affected  by  it 
vibrate.  This  motion  goes  on  not  only  in 
the  entire  gill  connected  with  the  rest  of  the 
mussel,  but  even  in  the  smallest  pieces  cut  off 
from  it,  which  by  their  radiant  motion  swim 
briskly  through  the  sea-water." 

Leeuwenhoek  likewise  appears,  from  various 
passages  in  his  writings,*  to  have  perceived  the 
moving  cilia  in  the  Oyster  and  Mussel ;  he 
noticed  also  the  existence  of  the  motion  in 
detached  portions.  His  observations,  so  far  as 
they  go,  are  correct;  but  he  takes  no  notice  of 
the  currents  in  the  water ;  nor  does  he  seem  to 
have  perceived  the  relation  of  the  phenomenon 
to  the  respiratory  or  other  functions,  or  indeed 
to  have  formed  any  opinion  regarding  its  phy- 
siological use. 

Baker  alludes  to  Leeuwenhoek's  discoveries, 
and  relates  an  appearance  observed  by  himself 
in  the  Fresh-water  Mussel,  which  must  have 
been  caused  by  the  ciliary  motion.f  He  states 
that  "  on  snipping  off  a  piece  of  the  transpa- 
rent membrane  (gill),  and  viewing  it  with  the 
microscope,  the  blood  will  be  seen  passing 
through  numbers  of  veins  and  arteries,  and  if 
the  extremity  of  the  membrane  be  viewed,  the 
true  circulation  or  the  return  of  the  blood  from 
the  arteries  through  the  veins  will  be  shewn." 
Dr.  Hales,  in  his  Statical  Essays,  (vol.  ii. 
p.  93,)  plainly  alludes  to  the  same  phenomena. 
Among  more  recent  writers,  Professor  Ehrman 
of  Berlin,  in  a  memoir  on  the  blood  of  the 
Mollusca,  published  in  the  Transactions  of  the 
Royal  Academy  of  Sciences  of  Berlin  for 
1 81 6-1 7,  J  has  described  an  appearance  no- 
ticed by  him  in  Mya,  Anodonta,  the  Oyster, 
and  other  Bivalves,  which  seems  evidently  to 
have  been  produced  by  the  ciliary  motion.  He 
states  that  on  viewing  the  inner  side  of  the 
labial  appendages,  accessory  gills,  or  tentacula 
of  these  Mollusca,  while  it  was  illuminated  by  a 
strong  light  falling  in  a  particular  direction,  he 
perceived  a  very  rapid  and  incessant  motion 
along  the  transverse  stripes  or  furrows  obser- 
vable on  the  surface  of  the  part.  The  motion 
proceeded  along  each  stripe  like  a  series  of 
oscillations.  It  continued  for  some  time  in 
portions  cut  off  from  the  organ.  He  next  ob- 
served that  a  number  of  round  vesicular  bodies 
escaped  from  the  furrows  or  stripes  at  the  part 
where  they  were  cut,  which  bodies  moved  to 
and  fro  and  as  it  were  spontaneously  in  the 
water;  and  it  seemed  to  him  that  in  proportion 
as  these  bodies  escaped,  the  oscillatory  motion 
relaxed  in  intensity.  From  these  facts  he  con- 
cluded that  the  motion  apparent  on  the  surface 
of  the  part  was  produced  by  the  agitation  of 
these  vesicles  or  animated  molecules  within 
the  furrows  ;  that  is,  he  supposed  the  furrows 
to  be  covered  by  a  membrane  to  which  an 

*  Epist.  83,  in  Opp.  i.  p.  463,  482.  Anat.  et 
Contemp.  p.  52  in  Opp.  ii.  Ibid.  p.  27.  Contin. 
Arcan.  p.  17  in  Opp.  ii. 

t  Of  Microscopes,  &c.  vol.  i    p.  128. 

j  P.  214,  seq. 


CILIA. 


625 


oscillatory  motion  was  communicated  by  the 
agitation  of  the  globules  underneath  it.  He 
perceived  the  motion  in  question  in  no  part 
but  the  labial  appendages,  and  he  imagined  it 
to  be  connected  with  the  male  generative  func- 
tion, of  which  he  therefore  conceived  the  parts 
mentioned  to  be  the  organs.  It  is  obvious  that 
the  appearance  seen  by  Ehrman  was  the  undu- 
lating motion  of  the  cilia,  which  organs,  how- 
ever, he  had  not  recognised.  He  makes  no 
mention  of  currents,  and  consequently  could 
not  perceive  the  connexion  of  the  phenomenon 
with  respiration,  which  was  also  less  likely  to 
occur  to  him,  as  he  supposed  the  motion  to  be 
confined  to  the  appendages  mentioned. 

The  observations  of  Ehrman  led  Treviranus 
to  investigate  the  subject;*  and  he  distin- 
guished two  different  motions,  the  one  a  mus- 
cular contraction,  the  other  the  peculiar  motion 
alluded  toby  Ehrman.  The  latter  motion  had 
the  appearance  of  a  trembling  or  flickering 
of  innumerable  points,  and  seemed  at  some 
places  as  if  produced  by  a  moving  fluid,  and 
at  others  by  the  agitation  of  oblong  vibrating 
organs.  It  was  peculiarly  distinct  alongside 
each  of  the  bars  of  the  gills  and  appendages. 
He  farther  perceived  that  the  agitation  on  the 
surface  of  these  parts  caused  an  eddying  mo- 
tion in  the  water  in  which  they  lay,  and  also 
set  in  motion  globules  of  blood  which  had 
escaped  from  the  vessels.  On  breaking  down 
the  parts  into  small  fragments,  he  found  that 
each  retained  its  power  of  motion,  by  which 
they  moved  in  most  manifold  directions,  the 
larger  masses  at  the  same  time  contracting  and 
dilating  themselves.  From  these  observations 
Treviranus  concludes  that  the  bivalve  Mollusca 
afford  an  example  of  a  structure  in  which  the 
integrant  parts  possess  an  independent  vitality. 
Their  independent  vitality  shews  itself  in  the 
persistence  of  their  automatic  motion  after 
solution  of  organic  connexion  with  each  other, 
and  this  motion  is  intermediate  in  its  nature 
between  the  spontaneous  movements  of  organic 
molecules  in  infusions,  the  male  semen,  &c. 
and  the  motion  of  muscular  parts,  which  re- 
quires the  integrity  of  the  texture  and  the 
application  of  a  stimulus.  These  reflections 
on  the  relation  of  the  phenomenon  to  the 
general  laws  of  organization  are  the  sole  infe- 
rences which  he  draws  from  his  observations. 
He  notices  the  motion  of  the  water  only  as  a 
concomitant  and  subordinate  circumstance,  not 
having  been  aware  of  its  determinate  direction, 
its  relation  to  the  respiratory  process,  or,  in 
short,  of  its  being  the  chief  end  and  effect  of 
the  motion  of  the  cilia. 

The  next  researches  on  the  subject  are  those 
of  Huschke,  narrated  in  a  paper  in  the  Isis  for 
1826.f  Not  having  seen  the  original,  we  must 
content  ourselves  with  a  brief  notice  of  them  to 
be  found  in  Burdach's  Physiologie.J  It  is  there 
stated  that  on  detaching  a  portion  of  the  gill 
of  the  Fresh-water  Mussel  (Unio  pictorum), 
Huschke  found  that  the  water  "  moved  up- 

*  Vermischte  Schriftcn,  Band  iii.  p.  234. 

t  P.  623. 

j   Band  iv.  p.  434. 


wards  en  one  side,  and  then  in  an  eddying 
manner  back  again." 

Raspail,  in  a  memoir  on  a  species  of  fresh- 
water polype,  published  in  1828,*  pointed  out 
the  analogy  between  the  phenomena  exhibited 
by  the  gills  of  Mollusca  and  those  observed  in 
infusory  animalcules  and  polypi. 

Ciliary  currents  were  now  described  by  vari- 
ous other  writers  of  eminence,  but  their  causes 
were  very  commonly  mistaken:  among  the 
number  may  be  quoted  Poli,f  Delle  Chiaje,J 
Carus,§  De  Blainville,||  and  Unger.^f 

Having  observed  currents  produced  in  other 
instances  by  an  impelling  power  inherent  in 
the  surfaces  over  which  the  fluid  passed,  I  was 
myself  led  to  suspect  that  the  respiratory  cur- 
rent in  bivalve  Mollusca  was  of  the  same  kind, 
or  that  it  was  caused  by  an  impulsion  commu- 
nicated to  the  water  by  the  surface  of  the  gills 
and  other  parts  over  which  it  was  conveyed  in 
its  passage,  without  being  aware  of  any  similar 
view  having  been  entertained  by  others.  I 
then  observed  the  determinate  direction  of  the 
impulsion  along  the  surface,  together  with  the 
arrangement  and  action  of  the  cilia.  These 
observations  were  published  at  the  time  (1830) 
in  a  paper  already  mentioned,**  in  which  also 
the  respiratory  currents  of  the  bivalve  Mollusca 
are  considered  as  a  particular  exam'ple  of  a 
more  generally  prevailing  phenomenon. 

In  a  paper  on  the  circulation  of  the  blood, 
in  Magendie's  Journal  for  1831,ft  there  are 
some  remarks  pertaining  to  the  present  subject, 
from  which  it  appears  that  the  author,  M. 
Guillot,  had  observed  the  ciliary  motion  of  the 
gills  of  the  Sea-mussel  and  Oyster.  He  has, 
however,  like  Baker,  mistaken  the  regular  un- 
dulations of  the  cilia  for  the  circulation  of  a 
fluid  within  vessels.  He  takes  no  notice  of 
any  motion  or  current  excited  in  the  water. 

Carus,|J  in  a  memoir  on  the  development  of 
the  River-mussel,  states  that  he  observed  an 
undulatory  or  oscillatory  motion  of  the  gills, 
and  that  by  this  motion,  which  he  conceives  to 
be  in  the  substance  of  the  gill,  the  water  is 
propelled,  and  the  general  respiratory  current 
through  the  branchial  cavity  produced.  It  is 
obvious  that  what  he  calls  an  oscillation  of  the 
substance  of  the  gill,  and  which  he  erroneously 
supposes  has  previously  escaped  attention,  is 
merely  the  undulatory  motion  of  the  cilia. 

The  last  researches  on  this  subject  which  we 
have  to  notice  are  those  of  Purkinje  and  Va- 
lentin^ As  above  stated,  they  discovered  the 
ciliary  motion  in  the  alimentary  canal  of  the 
Mollusca,  having  found  it  in  the  Lymnsca,  Pa- 
ludina,  and  the  Fresh-water  mussel. 


*  Memoires  de  la  Soc.  d'Hist.  Nat.  de  Paris, 
tome  iv.  p.  131,  seq.  Chimie  Organique,  1833, 
p.  246. 

t  Testacea  utriusque  Siciliae,  t.  i.  51. 

t  Istituz.  di  Notom.  e  Fisiolog.  comp.  t.  i.  p.  278. 

§^Lehrbuch  der  Zootomie. 


II   Malacologie,  157. 


H    Uber  die  Teichmuschel,  p.  10. 
*  Edin.  Med.  and  Surg.  Journal,  vol.  xxxiv. 
ft  Tom.  xi.  p.  182. 

«  Nova  Acta  Acad.  Caes.  Lcop.  xvi.  p.  58,  scq. 
|«   Loc.  cit. 


CILIA. 


Such  is  an  outline  of  the  observations  hitherto 
made  relative  to  the  ciliary  motion  in  the 
bivalve  Mollusca.  We  may  now  shortly  con- 
sider those  which  refer  to  the  other  classes  of 
these  animals. 

Dr.  Fleming,*  in  describing  the  cilia  in 
some  species  of  Polypi,  states  that  "  analo- 
gous hairs"  exist  on  the  branchiae  of  the  Tri- 
tonia,  which  may  probably  be  considered  as 
forming  part  of  the  aerating  organs.  He 
also  mentions,  in  another  place,f  that  these 
branchiae  "  readily  fall  off,  and,  as  if  indepen- 
dent, are  capable  of  swimming  about  for  a 
short  time  in  the  water,  by  means  of  minute 
hairs  with  which  their  surface  is  covered,  and 
which  move  rapidly,  pushing  forwards  the 
distal  extremity."  Gruithuisen,  as  formerly 
mentioned,  observed  the  ciliary  motion,  and 
recognised  its  true  nature  in  the  Valvata  bran- 
chiata,  a  species  of  fresh-water  snail.  Also 
Iiaspail,J  having  seen  the  phenomena  pro- 
duced by  the  gills  of  the  Fresh-water  Mussel, 
was  led  by  analogy  to  discover  the  same  in  the 
Lymnaea  and  Paludina.  Without  being  aware 
of  these  previous  researches,  I  observed  the 
ciliary  motion  in  several  different  tribes  of 
marine  Mollusca,  and  shewed  that  it  prevailed 
extensively  among  Mollusca  generally.  Mr. 
Lister,  as  has  been  already  stated,  has  subse- 
quently discovered  that  it  exists  in  the  Ascidia; 
and  since  then  I  have  also  found  it  in  that 
animal,  though  in  a  different  species. 

9.  Of  the  ciliary  motion  of  the  embryo  of 
Mollusca. — The  embryo  of  Mollusca  exhibits, 
while  within  the  egg,  a  peculiar  rotatory  mo- 
tion which  belongs  to  the  class  of  phenomena 
we  are  here  considering,  and  is  referable  to  the 
same  cause.  This  motion  has  been  observed 
in  the  Gasteropodous  and  Bivalve  Mollusca, 
and  may  perhaps  be  found  in  others. 

Gasteropoda. — Swammerdam§  states  that  in 
examining  the  young  of  the  viviparous  water- 
snail,  while  they  were  yet  inclosed  in  the  mem- 
branes of  the  ovum,  he  observed  the  embryo 
turning  round  in  the  contained  fluid  with  con- 
siderable rapidity,  and,  he  adds,  "  in  a  very 
elegant  manner."  He  again  mentions  the  fact 
in  another  place.||  Baker  observed  the  same 
appearance  in  the  ova  of  a  fresh-water  snail, 
which  appears  to  have  been  the  common  Lym- 
naea. He  says,H  "  when  the  eggs  are  about  a 
week  old,  the  embryo  snail  may  be  discerned 
in  its  true  shape,  turning  itself  very  frequently 
within  the  fine  fluid  in  which  it  lies."  These 
brief  notices  of  this  remarkable  fact  by  Swam- 
merdam  and  Baker  seem  to  have  failed  to  ex- 
cite the  curiosity  of  succeeding  naturalists,  for 
there  would  appear  to  be  no  account  of  any 
subsequent  researches  on  the  subject  till  those 
of  Stiebel  published  in  1815,**  who  seems  not 

*  Mem.  of  Wern.  Soc.  of  Edin.  iv.  p.  488. 

t  Philosophy  of  Zoology,  v.  ii.  p.  470. 

j  Loc.  cit. 

$  Biblia  Naturae,  p.  142. 

(I  Op.  cit.  p.  179. 

f  Of  Microscopes,  &c.  vol.  ii.  p.  325,  329. 

**  Diss.  sist.  Lymnaei  stagnalis  anatomen,  Goet- 
ting,  1815,  and  Meckel's  D.'utsches  Archiv  fur  die 
Physiologic,  Bd.  i.  p.  424.  Bd.  ii,  p.  557. 


to  have  been  aware  that  the  fact  had  been  pre- 
viously noticed.  Stiebel's  observations  were 
made  on  the  ova  of  the  Lymnaeus  stagnalis. 
They  were  followed  by  those  of  Hugi*  in  1823, 
and  Carus  in  1824,f  on  the  same  species,  to 
which  Carus  afterwards^  (in  1827)  added  cor- 
responding observations  on  the  Paludina  vivi- 
para.  About  the  same  time  (1827)  Dr.  Giant 
extended  the  inquiry  to  salt-water  Gasteropoda, 
both  naked  and  testaceous,  and,  as  far  as  I 
know,  was  the  first  to  point  out  the  cilia,  which 
are  very  conspicuous  in  salt-water  species,  as 
the  agents  which  cause  the  rotation. 

The  eggs  of  the  Lymnseus  (or  Lymnaea)  are 
deposited  in  clusters,  being  imbedded  in  oblong 
masses  of  gelatinous  matter  that  are  found  ad- 
hering to  stones  or  water-plants.  Each  egg 
consists  of  an  oval  pellucid  membrane,  con- 
taining within  it  the  yolk  surrounded  by  a  con- 
siderable quantity  of  limpid  fluid.  The  yolk 
is  at  first  round,  without  any  obvious  distinc- 
tion of  parts,  but  in  the  progress  of  develop- 
ment it  changes  its  figure,  and  is  gradually 
converted  into  the  embryo,  of  which  the  shell 
and  several  principal  organs  can  soon  be  dis- 
tinguished. From  the  descriptions  of  the  au- 
thors above  mentioned,  as  well  as  from  some 
observations  made  by  myself,  it  appears  that 
the  embryo  is  at  first  motionless,  but  that  as 
soon  as  the  distinction  can  be  perceived  be- 
tween the  anterior  or  cephalic  extremity  and 
the  rest  of  the  animal,  its  rotatory  motion  com- 
mences. This  invariably  goes  on  in  the  man- 
ner indicated  by  the  larger  arrows  (c,  c)  in  the 
annexed  figure,  the  head  or  anterior  extremity 

Fig.  307. 


Embryo  of  Lymncea. 

continually  receding.  After  a  time  the  rota- 
tion is  combined  with  a  progressive  motion, 
by  which  the  embryo,  while  turning  on  its 
axis,  moves  onwards  at  the  same  time  along 
the  inside  of  the  egg,  performing  a  circuit  like 
a  planet  in  its  orbit.  The  path  described  by 
a  point  on  the  surface  is  indicated  by  the  spiral 
line  in  the  figure. 

Stiebel,  as  well  as  the  earlier  observers  men- 
tioned, is  silent  as  to  the  cause  of  this  curious 
phenomenon.  Carus§  at  first  denominated  it 
a  primitive  or  cosmic  motion,  without  clearly 

*  Isis,  1823,  p.  213. 

t  Von  den  aiissern  Lebensbedingungen  der 
weiss-und  kaltbliitigen  Thiere.  Leipz.  1824. 

\  Nova  Acta  Acad.  Caes.  Leop.  vol..  xiii.  p.  763. 
§  Von  den  axiss.  Lebensb.  p.  59. 


CILIA. 


627 


explaining  what  he  meant  by  the  term.  Having 
subsequently  discovered  that  a  current  existed 
in  the  fluid  in  an  opposite  direction  to  that 
followed  by  the  embryo,  he  ascribed  the  mo- 
tion to  an  attraction  and  repulsion  exerted  by 
the  substance  of  the  embryo  on  the  surround- 
ing fluid,*  more  especially  at  the  region  of  the 
body  where  the  respiratory  organ  was  afterwards 
to  be  developed,  and  justly  conceived  that  the 
chief  purpose  served  by  it  was  to  renew  the 
water  on  the  respiring  surface  of  the  embryo. 
The  attraction  and  repulsion  again  he  supposed 
to  be  produced  by  an  oscillatory  motion  which 
he  perceived  on  the  surface  of  the  embryo. 
This  oscillatory  motion,  although  he  describes 
it  as  taking  place  in  the  substance  of  the  animal, 
seems  to  be  nothing  else  than  the  usual  undu- 
latory  play  of  moving  cilia,  such  as  has  been 
already  described  in  other  instances, — indeed 
he  himself  compares  it  to  the  undulation  on 
the  arms  of  polypi.  I  have  distinctly  perceived 
the  cilia,  though  they  are  very  small,  in  the 
embryo  of  the  small  species  of  Lymnaea  com- 
mon in  this  country.  It  is  the  one  represented 
in  the  figure,  but  considerably  magnified.  The 
current  takes  place  along  the  whole  of  the  sur- 
face indicated  by  the  small  arrows,  which  also 
mark  its  direction,  being  opposite  to  that  in 
which  the  embrjo  moves.  The  cilia,  though 
they  probably  exist  over  all  this  surface,  were 
distinctly  seen  only  on  the  part  inclosed  be- 
tween the  dotted  lines  at  a;  it  required  a  dou- 
blet of  one-thirty-fifth  of  an  inch  focus  to  make 
them  visible. 

Appearances  similar  to  those  described  were 
discovered  by  Dr.  Grant  in  the  ova  of  Marine 
Gasteropoda.  In  examining  the  embryos  of 
the  Buccinum  undatum  and  Purpura  lapillus, 
which  are  inclosed  in  groups  within  transparent 
sacs,  he  was  struck  with  a  rapid  and  incessant 
motion  of  the  fluid  in  the  sac  towards  the  fore 
part  of  the  embryo,  and  he  observed  that  this 
motion  was  produced  by  cilia  placed  around 
two  funnel-shaped  projections  on  the  fore  part 
of  the  young  animal,  which  form  the  borders 
of  a  cavity  in  which  he  perceived  a  constant 
revolution  of  floating  particles.  He  also  ob- 
served these  circles  of  cilia  in  the  young  of 
other  testaceous  Mollusca,  as  the  Trochus, 
Nerita,  &c.  in  which  the  embryo  was  seen  re- 
volving round  its  axis.  He  met  with  the  same 
appearance  in  the  naked  Gasteropoda,  as  the 
Doris,  Eolis,  &c.  The  embryo  of  these  re- 
volves round  its  centre,  and  swims  rapidly 
forward  by  means  of  its  cilia,  when  it  escapes 
from  the  ovum.  My  own  observations  on  the 
ova  of  the  Buccinum  agree  generally  with  those 
of  Dr.  Grant.  The  larger  cilia  are  placed 
round  the  prominent  border  of  a  cavity  on  the 
fore  part  of  the  body,  but  the  surface  of  the 
foot  and  other  neighbouring  parts  is  also  ciliated, 
though  the  cilia  are  there  much  smaller.  Dr. 
Grant  assigns  various  uses  to  these  motions  ;  it 
seems  not  to  have  occurred  to  him  that  they 
were  connected  with  respiration,  although  there 
can  be  little  doubt  that  they  are  principally 
subservient  to  that  function. 

*  Nova  A  eta,  xiii.  p.  771. 


Acephala. — The  rotation  of  the  embryo  of 
bivalves  was  discovered  by  Leeuwenhoek,  and 
described  by  him  in  one  of  his  epistles,  dated 
October,  1695.*  On  examining  the  ova  of  a 
species  of  Fresh-water  Mussel  with  the  micro- 
scope, he  observed  the  embryo  turning  slowly 
round  within  the  egg,  like  a  sphere  revolving 
on  its  axis.  This  was  at  a  time  when  the  shell 
could  be  distinctly  perceived  on  the  young 
mussel ;  he  had  failed  in  discovering  the  phe- 
nomenon in  some  ova  of  the  same  species 
which  he  had  examined  at  an  earlier  period  of 
advancement.!  He  adds,  that  he  was  so  much 
delighted  with  the  spectacle  of  the  young  Mus- 
sels turning  round  within  the  egg,  that  he  spent 
two  hours  along  with  his  daughter  and  his 
draughtsman  in  contemplating  it.  Baster,J 
who  wrote  in  1762,  seems  to  have  observed  an 
appearance  of  the  same  kind  in  the  ova  of  the 
Oyster,  if  we  may  judge  from  a  reference  by 
Cavolini,  for  I  have  not  been  able  to  consult 
the  original.  More  recently  (1827)  Sir  E. 
Home  and  M.  Bauer  §  perceived  the  motion  in 
the  embryo  of  the  Fresh-water  Mussel,  as  de- 
scribed by  Leeuwenhoek,  but  erroneously  attri- 
buted it  to  a  small  worm  which  pierces  the 
egg  and  preys  on  the  young  mussel,  and  which, 
according  to  their  view,  by  dragging  on  it  pulls 
it  round  in  the  manner  described.  Lastly, 
Carus  subjected  the  phenomenon  to  a  more 
careful  investigation,  in  the  course  of  his  re- 
searches on  the  development  of  the  River  Mus- 
sel. ||  According  to  his  observations  the  em- 
bryo, at  the  time  the  motion  becomes  percepti- 
ble, has  acquired  a  flattened  triangular  shape 
(Jig.  308),  the  two  halves  of  the  shell  cover  its 
two  surfaces,  and  are  united 
together  by  the  hinge  at  the  Fig.  308. 

base  of  the  triangle.  When 
the  ovum  is  placed  under 
the  microscope,  the  embryo 
is  seen  moving  round  in  a  ho- 
rizontal direction,  as  indica- 
ted by  the  larger  arrows,  ap- 
pearing as  if  it  turned  on  the 
centreof  the  lowermost  shell.  Embryo  of  Mussel. 
When  the  embryo  is  extract- 
ed from  the  egg,  a  current  is  perceived  in  the 
water  opposite  that  part  where  the  current  en- 
ters and  issues  in  the  adult  animal,  (as  shown 
by  the  small  arrow,)  and  Carus  therefore  attri- 
butes its  rotatory  motion  to  an  attraction  and 
repulsion  exerted  on  the  water  by  that  part 
of  the  embryo,  which  is  afterwards  to  form 
the  respiratory  organ.  The  attraction  and  re- 
pulsion of  the  water  he  supposes  to  be  pro- 
duced by  an  oscillatory  motion  observable 
in  the  substance  of  the  animal  at  its  surface,  as 
in  the  embryo  of  the  snail,  which  motion,  as  we 
have  already  seen,  is  in  reality  an  undulatory 
movement  of  minute  cilia.  As  in  the  snail 
also,  he  conceives  the  phenomenon  to  be  con- 
nected with  respiration.  For  an  account  of  his 

*  Ep.  95.     Com.  Arc.  Nat.  1697,  p.  26,  27,  in 
Op.  torn.  ii. 
t   Ibid.  p.  20. 

\  Opuscula  Subscciva,  torn.  ii.  p.  146. 
«   Phil.  Trans.  1827,  p.  39. 
J|  Nov.  Ada,  xvi.  p.  27,  sqq. 


628 


CILIA. 


observations  on  the  velocity  and  direction  of 
the  motion,  and  its  supposed  influence  in  de- 
termining the  figure  of  the  animal,  I  must  refer 
to  the  paper  itself. 

The  analogy  of  these  motions  of  the  embryo 
of  the  Mollusca  with  the  phenomena  exhibited 
by  the  ova  of  Infusoria,  Polypi,  Sponges,  and 
Actiniae,  already  described,  scarcely  requires  to 
be  pointed  out.  We  shall  afterwards  see  that 
it  extends  to  the  ova  of  Batrachian  Reptiles.* 

11.  Phenomena  of  the  ciliary  motion  in  the 
Vertebrata. — The  ciliary  motion  exists  very  ex- 
tensively in  vertebrated  animals.  Until  lately 
it  had  been  found  only  in  the  larvae  of  Batra- 
chian Reptiles,  but  Purkinje  and  Valentinf 
have  recently  made  the  important  discovery 
that  it  exists  also  in  adult  Reptiles,  Birds,  and 
Mammiferous  animals;  and  it  seems  to  prevail 
generally  throughout  the  three  classes,  having 
been  found  by  these  naturalists  in  all  the  nume- 
rous examples  of  each  class  examined  by  them 
in  the  course  of  their  investigations.  It  has 
not  been  found  in  Fishes,  though  many  species 
have  been  submitted  to  examination  .J 

The  parts  of  the  body  which  exhibit  the 
ciliary  motion  in  the  Vertebrata  are,  the  lining 
membrane  of  the  respiratory  organs,  and  that  of 
the  generative  organs  in  the  female.  Besides 
this  general  situation,  it  is  found  on  the  external 
gills  and  surface  of  the  body  in  the  larvae  of 
Batrachia,  and  on  the  surface  of  the  embryo  of 
these  reptiles  while  contained  within  the  ovum. 

A.  Reptiles. — The  ciliary  motion ,  has  been 
discovered  in  all  the  orders  of  Reptiles.  It  has 
been  found  in  every  species  submitted  to  ex- 
amination, and  is  therefore  presumed  to  exist 
in  all. 

^Batrachian  Reptiles.  1st.  Larv<s  and  ova. 
— The  Batrachian  Reptiles,  while  in  the  foetal 
or  larva  state,  breathe  by  means  of  gills  or 
branchiae,  and  it  wa&  on  the  gills  of  the  young 
Salamander  and  Frog  that  the  phenomenon  under 
consideration  was  first  discovered  as  existing  in 
vertebrated  animals.  The  gills  of  the  young 
Salamander  might  in  appearance  be  compared 
to  feathers  or  pinnated  leaves ;  there  are  three 
on  either  side,  each  consisting  of  a  main  stem 
bearing  two  rows  of  simple  leaflets ;  they  are 

*  In  the  preceding  account  of  the  ciliary  motions 
in  the  Invertebrata  no  mention  has  been  made  of 
their  existence  in  the  class  Crustacea  :  I  think  it 
necessary  to  state  that  I  have  examined  this  class, 
but  without  success  ;  and  since  these  pages  have 
been  put  into  the  printer's  hands  I  have  re-exa- 
mined the  crab  and  lobster  with  the  greatest  care, 
all  the  respiratory  and  alimentary  surfaces,  the 
inner  surface  of  bloodvessels,  &c.  with  lenses  of 
all  powers,  but  without  finding  the  phenomenon.  I 
suspect  the  respiratory  currents  in  Crustacea  which 
are  produced  by  the  motion  of  the  branchiae  them- 
selves, or  of  the  plates  or  oars  with  which  many 
are  provided  in  order  to  renew  the  water,  have  been 
confounded  with  the  currents  produced  by  cilia, 
more  especially  as  many  of  the  organs  employed 
for  the  purpose  in  the  Crustacea  are  fringed  with 
long  hairs ;  but  I  would  scarcely  reckon  such  mo- 
tion as  ciliary  any  more  than  those  occasioned  by 
the  gill-covers  of  a  fish. 

t  Mullens  Archiv.  1834.  Edinb.  New  Philos. 
Journal,  xix.  and  Comm.  Phys.  de  Phenomeno 
motus  vibratorii  continui.  Wratislav.  1835,  4to. 

%  See  note  at  p.  29. 


wholly  external,  projecting  backwards  and  out- 
wards from  the  side  of  the  neck.  The  tadpole 
of  the  Frog  (fg.  309)  has  at  first  gills  resem- 

Fig.  309. 


Larva  of  Frog. 

bling  those  of  the  Salamander,  but  of  a  simpler 
form;  they  are  also  three  on  each  side,  but  have 
each  only  five  or  six  diverging  branches.  The 
gills  of  the  Salamander,  although  not  perma- 
nent, endure  till  the  animal  makes  full  use  of 
its  lungs,  but  the  external  gills  of  the  Frog  are 
of  very  short  duration,  being*  soon  superseded 
by  internal  gills,  more  resembling  those  of  a 
fish,  with  which  the  animal  respires  for  the  rest 
of  the  larva  state. 

By  means  of  the  microscope  the  blood  may 
be  seen  circulating  through  the  external  gills  of 
the  Frog  and  Salamander ;  it  passes  outwards  to 
their  extremities  by  the  branchial  arteries,  and 
returns  in  a  contrary  direction  by  the  branchial 
veins.  The  water  also  is  moved  continually 
over  these  organs,  for  the  purpose  of  respira- 
tion, in  a  constant  and  determinate  direction, 
and  this  is  effected  by  the  peculiar  impelling 
power  we  are  here  considering,  viz.  the  ciliary 
motion  on  their  surface. 

Steinbuch,*  a  German  naturalist  already 
mentioned,  while  examining  the  circulation  of 
the  blood  in  the  gills  of  the  Salamander,  ob- 
served that  small  bodies  floating  in  the  water 
were  carried,  as  if  by  attraction,  to  the  surface 
of  the  gill,  and  again  repelled  from  it.  He 
also  found  that  portions  detached  from  the  gill 
moved  themselves  through  the  water,  or  if  kept 
fixed,  continued  as  before  to  attract  and  repel 
small  objects  in  their  vicinity.  From  these 
and  similar  facts  he  was  led  to  conclude  that 
the  water  was  continually  propelled  over  all 
parts  of  the  gill,  that  the  current  thus  produced 
served  to  renew  the  water  in  the  process  of  re- 
spiration, that  the  power  producing  the  propul- 
sion resided  in  the  gill,  and  was  exercised  in- 
dependently of  the  will  of  the  animal ;  and 
lastly,  from  the  analogy  of  Infusoria  and  Polypi, 
in  which  currents  are  produced  by  cilia,  he  in- 
ferred that  in  this  case  also  the  water  was  pro- 
bably impelled  along  the  surface  by  the  action 
of  cilia,  though  he  could  not  actually  perceive 
any  such  organs.  Steinbuch  next  examined 
the  tadpole  of  the  Frog,  and  found  that  its  ex- 

*  Analekten  neuer  Beobachtungen  und  Untersuch- 
ungcn  fur  die  Naturkunde,  Furth,  1802.  p.  46, 
sqq. 


CILIA. 


629 


ternal  gills  exhibited  the  same  phenomena,  but 
he  could  discover  nothing  of  the  kind  on  the 
internal  gills. 

Gruithuisen*  observed  in  the  tadpole  of  the 
Green  Frog  that  so  soon  as  the  circulation  of  the 
blood  began  in  any  part  of  the  gills,  small  ob- 
jects were  attracted  and  repelled  from  that  spot, 
and  that  the  same  took  place  a  few  days  later 
on  the  tail  wherever  vessels  had  been  formed. 
lie  conceived  that  the  motion  of  the  water  was 
for  the  purpose  of  exposing  the  blood  to  its  in- 
fluence, and  compared  it  to  the  current  pro- 
duced by  Infusoria  by  means  of  cilia.  He  does 
not  say,  however,  that  he  had  seen  cilia  in  the 
tadpole. 

Iluschkef  observed  that  the  water  in  the 
vicinity  of  the  gills  of  the  young  Salamander 
was  thrown  into  a  boiling-like  motion,  while  it 
flowed  steadily  at  other  parts  of  the  body. 

Without  being  aware  of  these  previous  disco- 
veries, I  was  led  in  1830,  by  an  accidental  ob- 
servation of  my  own,  to  go  over  nearly  the  same 
ground.}     I  had  cut  off  one  of  the  external 
gills  of  the  tadpole  of  the  Frog,  and  placed  it 
with  a  drop  of  water  under  the  microscope, 
with  the  view  of  measuring  the  size  of  the  glo- 
bules of  blood  that  might  flow  from  it,  and  was 
astonished  to  perceive  that  the  globules,   on 
escaping  from  the  cut  part  of  the  gill,  moved 
rapidly  along  its  surface  towards  the  points  of 
the  branches  in  a  constant  and  uniform  manner. 
On  further  inspection  it  soon  became  evident 
that  the  blood-globules  were  entirely  passive  in 
their  motion,   and    that  other   light   particles 
brought  near  the  gills  were  moved  in  a  similar 
manner ;  their  motion  being  manifestly  owing 
to  a  current  produced  in  the  water  along  the 
surface  of  the  gill  in  a  determinate  direction. 
A  conclusive  proof  of  this  was  afforded  by  put- 
ting the  gill  which  had  been  cut  off,    into  a 
watch-glass  with  a  larger  quantity  of  water.    It 
was  then  seen  that  when  the  gill  happened  to 
be  fixed  by  any  obstacle,  small  bodies  in  its 
vicinity  were  moved  along  it  as  before  towards 
the  points  of  the  branches,  but  when  unim- 
peded  the    gill  itself  advanced   through    the 
water  in  a  direction  contrary  to  that  in  which 
the  particles   were    moved,   the   trunk   being 
turned  forward ;    the  tendency  to  produce  a 
current  in  one  direction,  thus  causing  the  gill, 
now  no  longer  fixed,  to  move  in  the  opposite 
one.     The  current  began  at  the  root  of  the  gill, 
and  ran  along  the  branches,  at  the  points  of 
which  it  did  not  continue  its  primitive  direc- 
tion, but  turned  off  sideways,  and  immediately 
ceased.    (See  Jig.  309,  C). 

I  soon  found  that  the  gill  was  not  the  only 
part  of  the  animal  which  excited  motion  in  the 
water.  Nearly  the  whole  surface  of  the  body 
produced  the 'same  effect.  A  general  current 
commenced  on  the  fore  part  of  the  head,  pro- 
ceeded along  the  back  and  belly  and  the  two 


*  Salzburg.  Medicinisch-Chirurgische  Zeitung, 
1819,  ii.  p.  447. 

t  Isis,  1826,  p.  625,  (cited  in  Burdach's  Physio- 
logic, from  which  I  quote,  not  having  seen  the  ori- 
ginal.) 

$  Edinb.  Med.  and  Surg.  Journal,  xxxiv. 


sides,  to  the  tail,  along  which  it  continued  to  its 
extremity.  It  was  not  so  strong  as  that  on  the 
gills,  but  agreed  with  it  in  other  respects. 

I  continued  for  some  time  to  observe  the 
phenomenon  in  the  larva  of  the  Fro;?,  in  order 
to  find  out  whether  it  underwent  any  alteration 
in  the  progress  of  the  developement  of  that 
animal.  It  is  known  that  after  a  time  the  ex- 
ternal gills  become  covered  by  a  fold  of  the 
skin,  and  inclosed  in  the  same  cavity  with  the 
internal  gills,  when  they  gradually  shrink  and 
at  last  disappear.  On  examining  the  animal 
while  this  change  was  taking  place,  and  for 
some  time  after,  it  appeared  that  the  external 
gills  after  their  inclosure  still  retained  their 
peculiar  property,  and  continued  to  do  so  as 
long  as  any  portion  of  them  remained;  the 
current  on  the  body  remained  the  same ;  on  the 
tail  it  acquired  a  twofold  direction  diverging 
from  the  middle  part  or  continuation  of  the 
vertebral  column,  obliquely  upwards  and  down- 
wards towards  the  upper  and  lower  edge.  As 
the  animal  advanced  in  growth,  the  currents 
gradually  disappeared  over  the  greater  part  of 
the  surface,  continuing  longest  at  the  posterior 
part  of  the  body;  at  length,  when  the  pos- 
terior extremities  were  so  far  advanced  in 
growth  that  the  thigh,  leg,  and  toes  could  be 
discerned  with  a  magnifying  glass,  which  was 
the  latest  period  of  observation,  the  current 
existed  only  at  the  commencement  of  the  tail, 
and  on  a  small  part  of  the  body  near  the  hind 
leg.  The  internal  gills,  though  tried  in  various 
stages  of  development,  did  not  exhibit  the 
phenomenon. 

I  next  sought  for  the  same  appearances  in 
the  larva  of  the  Newt  or  Water  Salamander, 
which  was  first  examined  a  few  days  after  its 
exclusion  from  the  egg  when  its  gills  are  very 
simple.  At  this  period  the  surface  of  the 
animal  produces  currents  agreeing  in  almost 
every  circumstance  with  those  which  take 
place  in  the  larva  of  the  frog  at  a  correspond- 
ing stage  of  its  development.  Particles  of 
powder  diffused  in  the  water  are  carried  along 
the  surface  of  the  body  from  before  back- 
wards; on  the  gills  they  are  conveyed  along 
each  of  the  trunks  from  the  root  to  the  ex- 
tremity. The  gills  also,  when  cut  off,  move 
through  the  water  with  the  cut  extremity  for- 
wards, in  a  direction  contrary  to  the  currents. 
I  have  since  found  nearly  the  same  phenomena 
in  the  gills  at  a  much  later  period. 

It  was  evident  that  the  purpose  of  these 
currents  was  to  effect  a  renewal  of  the  water 
on  the  respiratory  surfaces;  respiration  in  these 
animals  probably  being  performed  not  only  by 
means  of  the  gills,  but  also  by  the  general  sur- 
face of  the  body. 

It  appeared  that  the  power  of  impelling  the 
water  was  wholly  confined  to  the  external  sur- 
face of  the  animal;  a  portion  of  the  skin  being 
raised  and  detached,  floating  bodies  were 
moved  along  its  external  surface  only.  Parts 
cut  off  from  the  animal  continued  to  excite 
currents  for  several  hours  after  their  separation, 
and  the  smallest  portion  produced  that  effect. 
In  these  cases  the  current  always  moved  in 
the  same  direction  relatively  to  the  surface  of 


630 


CILIA. 


the  detached  parts,  as  it  had  done  previous  to 
their  separation. 

At  the  time  of  making  these  observations 
I  had  not  been  able  to  detect  Cilia  in  these 
larvae,  although,  from  the  analogy  of  the  In- 
vertebrata,  I  was  led  carefully  to  look  for  them. 
Since  then  I  have  succeeded  in  perceiving 
them  with  the  aid  of  Wollaston's  doublet  of 
one-thirtyfifth  of  an  inch  focus,  especially  when 
a  portion  of  the  gill  is  compressed  under  a  plate 
of  mica.  They  are  to  be  distinguished  chiefly 
by  their  waving  motion,  which  is  so  charac- 
teristic as  to  remove  all  doubt  of  their  ex- 
istence ;  though  here,  as  in  other  instances  in 
which  they  are  very  minute,  it  is  not  always 
possible  to  demonstrate  their  existence  by 
actual  observation  on  every  spot  of  the  sur- 
face. 

Ova  of  the  Batrachia. — In  the  course  of 
the  above-mentioned  observations,  I  was  led 
to  enquire  whether  the  phenomena  in  question 
appeared  at  a  still  earlier  stage.  With  this 
view  I  examined  the  ova  of  the  Newt,  which 
for  a  considerable  time  may  be  procured  in  all 
degrees  of  advancement,  and  found  that  the 
ciliary  motion  presented  itself  in  the  embryo 
a  considerable  time  before  its  exclusion  from 
the  egg.  Since  then  I  have  observed  the  same 
with  regard  to  the  embryo  of  the  Frog. 

In  both  cases  the  embryo  is  formed  from 
the  yolk  or  opaque  central  part  of  the  ovum, 
by  a  series  of  changes  sufficiently  well  known ; 
it  is  surrounded  by  a  clear  fluid,  which  is 
inclosed  between  it  and  the  external  pellucid 
membrane  of  the  egg.  By  means  of  a  lens, 
minute  bodies  may  generally  be  perceived 
floating  in  the  fluid,  which  by  their  motion 
serve  to  indicate  the  currents  that  take  place 
in  it;  but  with  a  little  care  the  embryo  may 
be  extracted  from  the  egg,  and  then  the  course 
of  the  currents  along  its  surface  can  be  ren- 
dered more  evident  by  the  usual  means. 
A  (Jig-  310)  is  an  enlarged  view  of  the  embryo 


Fig.  310. 


Embryo  of  the  Frog. 

of  the  Frog  at  the  earliest  stage  at  which  I  have 
detected  the  motion.  The  vertebral  canal  is 
just  closed,  and  at  the  fore  part  of  the  body 
three  ridges  on  each  side  indicate  the  com- 
mencement of  the  gills.  The  arrows  point  out 
the  course  of  the  currents.  They  proceeded 
backwards  along  the  dorsal  surface,  diverging 
in  a  direction  downwards  and  backwards  on 
the  sides.  They  were  visible  but  weaker  on 
the  abdominal  surface.  B  represents  the  em- 
bryo farther  advanced,  the  currents  have  nearly 
the  same  direction  but  are  better  marked,  they 
are  strongest  on  the  lateral  eminences  of  the 


head  which  correspond  to  the  future  gills. 
In  the  embryo  of  the  Newt,  the  phenomena 
are  in  a  great  measure  similar ;  the  currents 
seemed,  however,  to  begin  and  to  continue  most 
vigorous  on  the  abdominal  surface;  they  are 
more  particularly  described  in  the  paper  re- 
ferred to. 

On  extracting  the  embryo  of  the  Frog,  and 
viewing  its  surface  in  profile  with  Wollaston's 
doublet,  moving  cilia  may  be  perceived  on 
various  parts.  They  appear  like  a  transparent 
undulating  line  on  the  surface,  and,  though 
very  minute,  are  so  distinct  as  to  leave  no  doubt 
of  their  existence. 

No  one  can  fail  to  perceive  the  analogy 
which  subsists  between  the  phenomena  just 
described,  and  those  which  occur  in  the  ova 
of  Zoophytes  and  Mollusca.  I  have  not  been 
able  distinctly  to  perceive  a  rotation  of  the 
embryo  of  the  Batrachia,  as  observed  in  the 
other  instances,  but  Purkinje  and  Valentin 
state  that  they  have  seen  it,  and  Rusconi  ob- 
served that  the  embryo  of  the  Frog,  when 
extracted  from  the  ovum,  turned  round  in  a 
certain  direction,  which  motion  he  supposed 
to  be  produced  by  water  entering  and  issuing 
through  pores  in  the  skin.* 

The  phenomena  in  the  Batrachian  larvae  have 
since  been  observed  by  Miiller,f  Raspail,J 
and  Purkinje  and  Valentin.§  The  last  men- 
tioned naturalists  also  distinguished  the  cilia 
and  perceived  the  motion  within  the  egg. 

Adult  Tlatrachia. — The  ciliary  motion  was 
discovered  in  the  adult  Batrachia  by  Purkinje 
and  Valentin  ;  indeed,  it  may  not  be  improper 
again  to  state  that  the  discovery  of  the  phe- 
nomena in  adult  Reptiles  generally,  and  in  Birds 
and  Mammiferous  animals,  is  due  to  these  phy- 
siologists. 

According  to  their  account,  the  ciliary  mo- 
tion in  the  Batrachia,  as  well  as  in  all  other 
vertebrated  animals  in  which  they  have  dis- 
covered it,  occurs  in  two  situations  within 
the  body,  viz.  on  the  lining  membrane  of  the 
respiratory  organs  and  on  that  of  the  genital 
organs  of  the  female.  They  state  that  it  exists 
over  the  whole  internal  surface  of  the  lungs, 
and  in  the  nose,  mouth,  and  pharynx,  extend- 
ing as  far  back  in  the  throat  as  the  glottis,  but 
no  farther.  They  say  nothing  of  the  direction 
of  the  impulsion.  Again,  in  the  female,  they 
discovered  the  motion  on  the  internal  surface 
of  the  oviduct.  The  result  of  my  own  ex- 
amination of  the  Newt,  Frog,  and  Toad  is 
somewhat  different.  In  all  the  three  I  found 
the  ciliary  motion  very  distinct  in  the  mouth, 
throat,  and  gullet;  in  none  could  I  perceive  it 
in  the  lungs,  notwithstanding  very  careful  trials. 
In  regard  to  the  oviduct  I  have  examined  it 
only  in  the  Newt,  and  although  I  could  per- 
ceive something  like  the  motion  on  the  edges 
of  its  superior  orifice,  I  could  not  detect  it  on 
the  internal  surface  of  the  tube.|| 


*  Sur  le  Developpement  de  la  Grenouille  Com- 
mune.    Milan,  1826. 

t  Burdach's  Physiologie,  Bd.  iv.  p.  434. 
Chimie  Organique,  1833,  p.  250. 
O.  cit. 
lin.  New  Phil.  Journal,  xix. 


I  Edh 


CILIA. 


631 


The  ciliary  motion  in  the  mouth  and  throat 
occurs  all  the  way  from  the  opening  of  the 
mouth  to  the  termination  of  the  oesophagus. 
Its  extent  and  the  direction  of  the  impulsion 
are  easily  ascertained  by  means  of  powdered 
charcoal ;  they  are  pointed  out  by  the  arrows 
in  the  adjoining  figures,  A  and  B  (Jig.  311), 

Fig.  311. 


Salamander. 


which    are   taken    from    the   Newt,    the    ap- 

»pearances  in  the  Frog  and  Toad  being  not  ma- 
terially different,  a  is  the  lower  jaw  detached 
from  the  head,  b  the  tongue,  c  the  glottis, 
d  the  oesophagus  cut  off  from  the  head  (at  g,g, 
jig.  B),  and  laid  open  from  above,  e  the  sto- 
mach, andyj/j  the  lungs.  The  general  course 
of  the  impulsion,  or,  if  in  this  case  we  might 
so  express  it,  the  currents,  is  longitudinal ;  they 
begin  at  the  symphysis  of  the  lower  jaw  and 
extend  to  the  lower  end  of  the  oesophagus, 
where  they  terminate  abruptly  at  the  entrance 
of  the  stomach,  thus  differing  from  the  de- 
scription given  by  Purkinje  and  Valentin  ;  but 
it  is  worthy  of  notice  that  these  observers  de- 
scribe the  motion  in  the  Tortoise  and  Serpent 
as  extending  the  whole  length  of  the  oesopha- 
gus. At  particular  parts  the  impulsion  fol- 
lows the  direction  of  the  plaits  of  the  lining 
membrane.  Figure  B  represents  the  head  and 
the  roof  of  the  mouth,  from  which  the  lower 
jaw  has  been  separated.  On  this  part  of  the 
mouth  also  the  general  course  is  longitudinal, 
from  before  backwards ;  at  the  nostrils  h,  h, 
the  particles  are  drawn  in  at  one  edge  and  issue 
at  the  other,  as  indicated  in  the  outline  of 
figure  B. 

As  regards  the  use  of  the  ciliary  motion  on 
the  internal  membranes  of  the  Batrachia,  we 
can  scarcely  doubt  that  one  purpose  is  to 
convey  onwards  the  secretions  of  these  mem- 
branes in  the  direction  indicated.  It  is  not 
impossible  also  that  it  may  have  some  more 
intimate  connection  with  the  respiratory  pro- 
cess; but  on  this  point  we  have  not  as  yet  suf- 
ficient grounds  for  forming  a  probable  opinion. 

Sauria,  Ophidia,  and  Chelonia. — The  authors 
mentioned  describe  the  appearances  in  these 
reptiles  as  being  similar  to  what  they  have 


found  in  Batrachia.  The  ciliary  motion  oc- 
curs in  the  oviduct  and  in  the  nose,  mouth, 
pharynx,  Eustachian  tube,  and  inner  surface 
of  the  lungs.  In  the  Serpent  and  Tortoise  they 
state  that  it  extends  along  the  gullet  to  its 
termination  at  the  stomach,  as  we  have  seen  to 
be  the  case  in  the  Batrachia.  The  motion  of  the 
cilia  is  remarkably  vivid  in  the  mouth  of  the 
Serpent,  and  in  the  Tortoise  it  endures  for 
several  days  after  death,  not  ceasing  till  the 
parts  are  destroyed  by  putrefaction. 

B.  Birds. —  The    same    physiologists   have 
discovered  the  phenomena  in  thirteen  species 
of  Birds,  belonging  to   five  different  orders ; 
and  as  they  met  with  it  in  every  species  sub- 
mitted to  examination,  they  infer  that  it  exists 
in  all. 

In  Birds,  as  in  otherVertebrated  animals,  the 
motion  shows  itself  on  the  lining  membrane 
of  the  oviduct  and  that  of  the  respiratory 
organs.  It  was  detected  in  the  nasal  cavities 
and  Eustachian  tube,  in  the  windpipe  and  its 
divisions,  even  in  the  smallest  branches  capable 
of  investigation,  and  on  the  internal  surface 
of  the  large  sacs  or  receptacles  into  which  the 
air  penetrates.  No  trace  of  it  could  be  found 
in  the  mouth  and  pharynx.  In  regard  to  the 
direction  of  the  impulsion,  the  authors  state 
that  in  the  oviduct  they  had  found  it  to  be 
from  the  internal  towards  the  external  extre- 
mity of  the  tube,  and  in  the  windpipe  from  its 
orifice  towards  its  branches,  or  from  without 
inwards,  at  least  they  so  observed  it  once  in 
the  domestic  Fowl.  The  phenomenon  exists 
in  the  foetus  of  the  bird,  having  been  distinctly 
seen  in  the  foetal  pigeon  near  the  full  period. 

C.  Mammalia. — An  accidental  observation 
led  Purkinje    and   Valentin   to   discover  the 
ciliary   motion  in  Mammalia,    and    they  fol- 
lowed out  that  discovery  by  extending  their 
inquiries  to  other  vertebrated  animals.     While 
examining  the  Fallopian  tube  of  a  rabbit  that 
had  been   recently  impregnated,   in  order  to 
discover  the  ova,    they   chanced    to   observe 
small   portions   of  the  mucous  membrane  of 
the  tube  turning  round,  and  moving  briskly, 
and  recognized  the  appearance  as  an  instance 
of   ciliary   motion.      The  whole  uterus    and 
organs  of  generation  generally  were  then  dili- 
gently searched,  and  these  motions  were  dis- 
covered throughout  their  entire  extent,  though 
of  very  different  degrees  of  intensity  in  dif- 
ferent places.     They  were  particularly  brisk  in 
the  tubes,  less  so  in  the  cornua  of  the  uterus, 
still  less  in  the  conjoined  parts  of  the  organ, 
most  lively  of  all  on  its  swollen  and  dark  red 
lips,  and  of  considerable  strength  in  the  vagina. 
After   finding    the   same   appearances   in   the 
oviduct  of  Birds  and  Reptiles,  they  succeeded 
also  in  discovering  it  in  the  lining  membrane 
of  the  air-passages  in  all   the  three   classes. 
In   Mammalia  the  ciliary   motion  of  the  re- 
spiratory organs  occurs  on  the  mucous  mem- 
brane of  the  nose  and  its  sinuses,  and  that  of 
the  Eustachian  tube,  also  on  the  lining  mem- 
brane  of  the   lower  part  of  the  larynx,   the 
trachea,    and   bronchial   tubes,    extending   to 
their  smallest  divisions  capable  of  examination. 
No  trace  of  it  can  be  found  in  the  glottis,  nor 


632 


CILIA. 


in  the  mouth  and  pharynx.     It  was  also  sought 
for  unsuccessfully  in  the  lachrymal  passages. 

The  authors  mentioned  have  now  examined 
it  in  twelve  species  of  Mammalia,  and  have 
found  .  the  same  appearance  in  all  of  them ; 
they  add  that,  although  they  have  had  no  op- 

n  unity  of  inspecting  the  parts  in  the  human 
y  so  soon  after  death  as  to  see  the  cilia  in 
motion,  yet  by  covering  the  surfaces  to  be 
examined  with  blood,  which  preserves  the  ap- 
pearance longer  than  any  other  fluid,  they 
were  able  on  examination,  thirty  hours  after 
death,  satisfactorily  to  distinguish  the  cilia 
both  in  the  nose  and  windpipe. 

I  have  seen  the  phenomena  in  the  nose, 
trachea,  and  Fallopian  tubes  of  the  Rabbit,  and 
in  the  trachea  of  the  Dog.* 

According  to  Purkinje  and  Valentin  the 
motion  occurs  in  the  uterine  mucous  mem- 
brane, both  in  the  impregnated  and  unimpreg- 
nated  state;  but  in  gravid  animals  it  appears 
only  on  those  parts  of  the  uterus  which  are 
not  adherent  to  the  chorion  or  external  enve- 
lope of  the  foetus.  The  direction  of  the  impul- 
sion they  state  to  be  from  the  internal  ex- 
tremity of  the  tube,  towards  the  orifice  of  the 
vagina.  It  seems  wanting  on  the  genital  mem- 
brane of  young  animals.  On  the  other  hand, 
it  occurs  in  the  respiratory  passages  of  the 
fetus,  it  was  detected  in  foetal  calves  and 
lambs,  and  in  fetal  pigs  not  more  than  two 
inches  long.  The  authors  could  not  with  cer- 
tainty distinguish  the  direction  of  the  im- 
pulsion in  the  air-passages  of  Mammalia.  In 
some  parts  of  the  nose  of  the  Rabbit,  I  have 
been  able  to  trace  it  clearly  enough  by  means 
of  charcoal  powder,  the  parts  being  placed  in 
tepid  water.  On  the  inferior  turbinated  bone 
the  grains  of  powder  were  slowly  carried  for- 
wards, following  the  direction  of  the  project- 
ing laminae  of  the  bone.  On  breaking  open 
the  maxillary  sinus  and  trying  its  lining  mem- 
brane in  the  same  way,  the  impulsion  seemed 
to  be  directed  towards  the  back  part  of  the 
cavity,  where  its  opening  is  situated.  By  the 
same  means  I  traced  the  direction  in  the  wind- 
pipe of  a  young  dog  a  few  days  old  ;  the  im- 
pulsion was  best  marked  on  the  posterior  part 
of  the  tube,  and  there  it  was  obviously  di- 
rected towards  the  larynx,  the  direction  being 
thus  different  from  what  Purkinje  and  Valentin 
observed  in  the  domestic  Fowl. 

PART    II. 

1.  Summary  of  the  animals  in  which  the 
ciliary  motion 'has  been  discovered. 

From  the  foregoing  facts  it  appears  that  the 
ciliary  motion  is  a  phenomenon  which  prevails 
most  extensively  in  the  animal  kingdom,  hav- 
ing been  found  in  the  highest  as  well  as  the 
lowest  members  of  the  Zoological  scale. 
Among  Vertrebated  Animals  it  has  been  dis- 
covered in  Mammalia,  Birds,  and  Reptiles, 
viz.  the  Batrachia,  Sauria,  Ophidia,  and 
Chelonia.  Of  the  Invertebrata  it  has  been 
found  in  Mollusca,  viz.  Gasteropoda,  Conchi- 
ferous  acephala,  and  Tunicata  ;  in  Annelida, 

*  Edin.  New  Philos.  Journal,  xix. 


viz.  Aphrodita,  Arenicola,  and  many  Tubi- 
colur  worms,  also  in  Planar  ia  and  Naiades;  in 
Echinodermata,  viz.  the  Aster 'MS  and  Echinus; 
in  Actiniae;  in  Medusae;  in  Polypi;  in  Sponges; 
and  in  Infusoria.  It  is  a  remarkable  fact  that 
no  trace  of  it  has  been  observed  in  Fishes. 
I  at  one  time  supposed  that  the  pendent 
filaments  of  the  gills  of  the  fetal  Skate  and 
Shark  might  probably  be  found  to  exhibit  it ; 
but  my  friend,  Dr.  Allen  Thomson,  has  care- 
fully inspected  those  of  the  Skate  without 
being  able  to  perceive  any  appearance  of  it.* 

2.  Organs  or  parts  of  the  body  in  which  the 
ciliary  motion  has  been  ascertained  to  exist. 

These  may  be  referred  to  four  heads,  viz. 
the  skin  or  surface  of  the  body,  the  respiratory, 
alimentary,  and  reproductive  systems.  Its  use 
in  all  these  cases,  or  the  function  in  general  of 
the  cilia,  is  to  convey  fluids  or  other  matters 
along  the  surface  on  which  the  cilia  are  placed, 
or,  as  in  the  Infusoria,  to  carry  the  entire 
animal  through  the  fluid. 

a.  Surface  of  the  body. — Cilia   have   been 
found  on  different  parts  of  the  external  surface, 
in  Batrachian   larvse,   in  Mollusca,  Annelida, 
Echinodermata,    Actiniae,    Medusae,     Polypi, 
and  Infusoria.     Their  function  in  this  situation 
is  various  ;  in  most  cases  it  is  evidently  respi- 
ratory, but  in  many  instances  it  is  also  locomo- 
tive, as  in  Infusoria  and  Medusae,  or  prehensile, 
as  in  Infusoria  and  Polypi ;  and  perhaps  it  is 
in  some  animals   subservient  to  the  sense  of 
touch  or  smelling,  as  may  be  conjectured  with 
regard  to  the  cilia  on  the  tentacula  of  some 
Mollusca. 

b.  Respiratory  system. — The  ciliary  motion 
has  been  observed  on  the  lining  membrane  of 
the  air-passages  of  Mammalia,  Birds,  and  Rep- 
tiles;  and  there,  whatever  may  be  its  other 
uses,  it  at  least  serves  to  convey  the  secretions 
along  the   membranes,   together   with   foreign 
matters,  if  any  are  present.     It  exists  also  on 
the  external  gills  of  Batrachian  larvae,  and  on 
the  gills  of  Mollusca  and  Annelida.     In  other 
Annelida,  in   Echinodermata  and  Actiniae,   it 
is  found  on  the  external  surface  of  the  viscera 
and  on  the  parietes  of  the  cavity  containing 
them,  to  which  cavity  the   water  has  access. 
The  pores  and  canals  of  the  Sponge  are  pro- 
bably both  respiratory  and  alimentary  passages, 
and  under  this  head  we  must  refer  again  to  the 
cilia  on  the  external  surface  of  Medusae,  Polypi, 
and  Infusoria,  as  belonging  partly  to  the  respi- 
ratory system.     The  use  of  the  ciliary  motion 
on    the   respiratory   organs    of   animals    with 
aquatic  respiration  is  obviously  to  renew  the 
water  on  the  respiring  surface. 

c.  Alimentary  system. — The  motion  occurs 
in  the  mouth,  throat,  and  gullet  of  Reptiles, 
in  the  entire  alimentary  canal  of  Mollusca,  on 

*  Since  the  above  was  written,  a  short  notice 
has  appeared  in  "  1'Institut"  of  16th  December, 
1835,  "of  the  Transactions  of  the  Leopoldine  Aca- 
demy for  1834-35,  from  which  it  appears  that  Pur- 
kinje and  Valentin  have  at  last  succeeded  in  detect- 
ing the  phenomenon  in  Fishes.  They  found  it  in 
the  organ  of  smelling  and  the  internal  genital 
organs  of  the  female.  No  further  particulars  are 
stated. 


CILIA. 


633 


the  internal  surface  of  the  intestine  and  ccecal 
appendages  of  the  Aphrodita,  within  the  sto- 
mach and  coeca  of  the  Asterias,  in  the  stomach 
of  the  Actinia,  in  the  canals  of  the  Sponge, 
which  no  doubt  belong  partly  to  the  alimentary 
system,  and  in  the  mouth,  throat,  stomach,  and 
intestine  of  several  Polypi.  It  is  not  easy  to 
see  the  purpose  of  the  motion  in  all  these 
cases.  In  some  it  may  merely  convey  secreted 
matters  along  the  surface  of  the  lining  mem- 
brane; in  Polypi  it  agitates  the  food  within  the 
alimentary  cavity,  and  in  several  instances  it 
seems  almost  to  serve  in  place  of  ordinary 
deglutition,  to  carry  food  into  the  stomach. 

d.  Reproductive  organs. — The  phenomenon 
occurs  on  the  mucous  membrane  of  the  Fallo- 
pian tubes,  uterus,  and  vagina  of  Mammalia, and 
of  the  oviduct  in  Birds  and  Reptiles.  From 
the  direction  of  the  impulsion  being  from 
within  outwards,  it  is  difficult  in  the  meantime 
to  assign  any  other  office  to  the  cilia  in  this 
situation  than  that  of  conveying  outwards  the 
secretion  of  the  membrane,  unless  we  suppose 
that  it  also  brings  down  the  ovum. 

The  phenomenon  has  been  sought  for  in 
other  parts  of  the  body,  but  hitherto  without 
success.  Purkinje  and  Valentin  state  that  on 
examination  they  could  not  find  it  in  the  fol- 
lowing parts  of  vertebrated  animals,  viz.  the 
skin,  serous  membrane,  the  alimentary  canal, 
(except  the  mouth  and  gullet  of  Reptiles,)  the 
gall-bladder,  the  biliary  and  pancreatic  ducts,  the 
urinary  organs,  the  seminal  vesicles  and  ducts, 
the  conjunctiva,  cornea,  and  iris,  the  internal 
surface  of  the  bloodvessels,  the  globules  of 
the  blood  and  lymph,  the  chorion,  amnion, 
allantois,  and  yolk-sac  of  Birds.  I  have  also 
repeatedly  examined  the  foetal  membranes  of 
the  common  Fowl,  and  with  the  same  result. 

3.  Of  the  ciliary  motion  in  the  embryo. — 
According  to  Purkinje  and  Valentin  the  ciliary 
motion  of  the  genital  mucous  membrane  does 
not  appeal'  in  the  foetus,  nor  until  the  animals 
have  made  some  approach  to  the  adult  state; 
that  of  the  respiratory  passages  on  the  other 
hand  becomes  apparent  in  the  embryo  long 
before  it  attains  maturity.  The  ciliary  motion, 
however,  to  which  we  would  here  refer  is  that 
which  occurs  at  a  much  earlier  period  on  the 
surface  of  the  embryo  of  many  animals,  and 
generally  causes  it  to  perform  a  rotatory  move- 
ment within  the  ovum.  It  has  now  been  ob- 
served in  the  ova  of  Batrachia,  Mollusca,  Ac- 
tiniae, Polypi,  Sponges,  and  Infusoria.  \Vhile 
the  embryo  is  contained  within  the  ovum,  the 
cilia  produce  a  current  in  a  certain  direction 
along  its  surface,  or  cause  the  whole  embryo 
to  move  in  the  opposite  direction ;  hence  the 
very  remarkable  rotatory  motion  which  occurs 
in  many  instances,  and  which  is  so  well  marked 
in  the  Snail.  When  it  has  escaped  from  the 
egg,  the  embryo  moves  about  in  the  water  by 
means  of  the  cilia,  as  happens  also  with  the 
naked  gemmules  of  the  Sponge  after  they  are 
discharged  from  the  parent.  The  ciliary  mo- 
tion is  subservient  to  the  respiration  of  the 
embryo,  by  renewing  the  contact  of  the  water 
or  fluid  contained  in  the  egg  on  the  respiring 
surface,  and  in  some  instances,  the  Mollusca 

VOL.  i. 


for  example,  the  motion  is  observed  to  be 
especially  strong  at  the  part  where  the  respira- 
tory organ  is  afterwards  developed.  When  the 
embryo  quits  the  egg,  the  cilia  serve  also  for 
locomotion,  and  by  this  provision  the  gem- 
mules  of  fixed  zoophytes  are  disseminated,  and 
conveyed  to  situations  suitable  for  their  future 
growth. 

4.  Figure,  structure,  and  arrangement  of 
the  cilia  in  general. — The  cilia  are  best  seen 
when  their  motion  slackens  ;  their  shape,  size, 
arrangement,  and  manner  of  moving  may  then 
be  distinguished  with  tolerable  accuracy,  at 
least  in  the  larger  sort.  Their  figure  is  in 
general  that  of  slender,  conical,  or  sometimes 
slightly  flattened  filaments,  broader  at  the  base 
or  root,  and  tapering  gradually  to  the  point. 
Their  size  differs  greatly  on  different  parts  even 
of  the  same  animal,  but  on  corresponding 
parts  of  different  individuals  of  the  same 
species  their  size  seems  to  be  the  same.  The 
largest  I  have  measured  are  those  on  the  point 
or  angle  of  the  branchial  laminae  in  the  Buc- 
cinum  undatum ;  they  are  at  least  3£g  of  an  inch 
long.  I  have  not  attempted  to  determine  the 
exact  size  of  the  smallest,  but  Purkinje  and 
Valentin  state  it  at  0.000075  of  an  inch,  while 
they  make  the  largest  they  have  met  with  only 
0.000908  in.,  which  is  considerably  less  than  I 
have  found  them ;  but  they  had  no  opportunity 
of  examining  marine  animals,  in  which,  gene- 
rally speaking,  the  largest  cilia  are  met  with. 
In  the  Sea-mussel  the  darker-coloured  cilia  are 
about  ^  of  an  inch  long,  the  others  consider- 
ably less. 

The  cilia  are  very  generally  arranged  in  re- 
gular order.  In  some  cases  they  are  placed  in 
straight  rows,  as  on  the  gills  of  the  Mussel;  in 
others  they  form  circles  or  spiral  lines,  as  in 
many  Infusoria;  and  Purkinje  and  Valentin 
state  that  in  animals  of  the  higher  orders  the 
most  prevalent  mode  of  arrangement  is  in  spiral 
lines  or  ridges.  They  are  generally  set  close 
together  in  the  same  row  ;  on  the  gills  of  the 
Sea-mussel  I  find  there  are  seven  or  eight  of  the 
larger  cilia  in  the  length  of  -^  of  an  inch,  or 
about  seven  or  eight  thousand  to  the  length  of 
an  inch,  but  in  other  cases  there  are  many 
more.  In  some  instances  they  are  erect,  or  at 
right  angles  to  the  surface  on  which  they  are 
planted,  in  others  inclined,  and  then  it  would 
seem  that  the  inclination  is  in  the  direction  of 
the  currents  which  they  produce.  In  some 
parts  they  are  straight,  in  others  curved,  not 
only  when  in  action,  but  also  when  at  rest,  and 
the  points  are  bent  in  the  same  direction  in 
which  the  currents  flow. 

The  substance  of  the  cilia  is  transparent,  and 
for  the  most  part  colourless ;  in  some,  however, 
it  is  coloured  brown  or  yellowish  brown.  It 
appears  as  if  homogeneous,  even  when  highly 
magnified,  and  no  fibres  or  globules  are  distin- 
guishable in  it.  It  seems  to  vary  somewhat  in 
consistency,  for  the  cilia  on  some  parts  appear 
extremely  soft  and  pliant,  and  on  others  com- 
paratively firm  and  elastic,  though  still  abun- 
dantly flexible. 

There  is  a  peculiarity  in  the  form  of  the  cilia 
in  some  animals,  of  which  the  Beroe  and  other 

2  T 


634 


CILIA. 


Ciliograde  Medusae  afford  a  good  example.  In 
these,  in  place  of  cilia  of  the  usual  form  and 
arrangement,  there  are  rows  of  broad  flattened 
organs,  each  of  which  is  made  up  of  several 
simple  filaments  joined  together  by  a  common 
base,  according  to  Eschscholz,  or  according  to 
Dr.  Grant  by  a  connecting  membrane  in  their 
whole  length.  The  entire  organ  is  raised  or 
depressed  at  once,  so  that  the  filaments  are  all 
moved  simultaneously,  like  the  eye-lashes.  The 
compound  cilia  in  some  of  the  Rotatoria,  de- 
scribed by  Ehrenberg,  are  probably  of  the  same 
nature. 

5.  Of  the  appearance  of  the  cilia  in  motion. 
— On  examining  these  organs  with  a  lens  of 
^  inch  focus,  when  their  motion  is  not  very 
rapid,  the  manner  in  which  the  individual  cilia 
move  may  be  distinguished  with  tolerable  cer- 
tainty.    Most  commonly  they  have  a  fanning 
or  lashing  motion,  that  is,  the  cilium  is  bent  in 
one  direction  and  returns  again  to  its  original 
state.     The  flexion  takes  place  chiefly  at  the 
base  or  root,  but  not  wholly  there,  for  the 
rest  of  the  organ  is  obviously  bent  and  altered 
in  figure ;    nay,  the  more  elastic  cilia,  when 
their  motion  abates  in  intensity,  appear  some- 
times to  bend  only  near  the  point,  the  base 
and  adjoining  part  remaining  motionless. 

When  a  number  of  cilia  are  affected  in  suc- 
cession with  this  motion,  the  appearance  of  a 
progressive  wave  is  produced,  and  as  in  such  a 
case  they  are  again  and  again  moved  in  the 
same  way  at  very  short  intervals,  successive 
waves  proceed  along  them  in  the  same  direc- 
tion, which  might  be  compared  to  those  pro- 
duced by  the  wind  in  a  corn-field.  Such  at 
least  seems  to  be  the  true  explanation  of  the 
undulatory  motion  which  so  often  occurs, 
although  it  must  be  confessed  that  the  motion 
of  the  cilia  individually  cannot  be  distinctly 
seen  when  the  undulation  is  most  perfect.  The 
undulations  succeed  one  another  along  a  range 
of  cilia  with  great  regularity,  and  except  in 
the  Rotifera,  and  perhaps  some  other  Infusoria, 
they  seem  always  to  maintain  the  same  direc- 
tion in  the  same  parts. 

Purkinje  and  Valentin  describe  the  motion 
of  the  individual  cilia  as  being  more  frequently 
rotatory,  or,  as  they  term  it,  infundibuliform ; 
and  Ehrenberg  states  this  to  be  the  common 
mode  in  the  Infusoria ;  the  cilium  describing  a 
circle  with  its  point,  while  the  base  is  the  centre 
of  motion.  From  my  own  observation,  how- 
ever, I  would  be  inclined  to  infer  that  this 
motion  is  by  no  means  the  most  common. 

6.  Duration  of  the  ciliary  motion  after  death 
and  in  separated  parts. — The   continuance  of 
the  ciliary  motion  for  some  time  after  death, 
and  the  perfect  regularity  with  which  it  goes  on 
in  parts  separated  from  the  rest  of  the  body,  are 
facts  which  have  been  already  repeatedly  .stated, 
and  sufficiently  prove  that  the  motion  is  quite 
independent  of  the  will  of  the  animal,  and  also 
that  it  is  not  immediately  influenced  by  the 
circulation  of  the  blood,  even  in  the  respiratory 
organs. 

The  time  which  it  continues  after  death 
differs  in  different  species  of  animals,  and  also, 
but  in  a  much  smaller  degree,  in  different  parts 


of  the  same  animal.  Its  duration  is  influenced 
also  by  the  temperature  of  the  air,  and  by  the 
nature  of  the  fluid  in  contact  with  the  surface. 
In  Mammalia  and  Birds  the  period  varies  from 
half  an  hour  to  four  hours,  being  longer  in 
summer  than  in  winter;  but  it  is  still  further 
prolonged  when  the  parts  are  covered  with 
blood.  In  the  gills  of  Batrachian  larvae  I  have 
seen  the  motion  continue  six  hours;  but  of  all 
vertebrated  animals  it  is  most  enduring  in  the 
Tortoise,  in  which  animal  Purkinje  and  Valen- 
tin affirm  they  observed  it  fifteen  days  after 
death,  when  putrefaction  was  far  advanced ; 
the  irritability  of  the  muscles  remained  in  the 
same  animal  for  seven  days.  Among  the  in- 
vertebrata  the  River-mussel  affords  an  instance 
of  the  great  pertinacity  of  the  motion,  which 
ceases  only  when  putrefaction  has  advanced  so 
far  as  actually  to  destroy  and  dissolve  the 
tissues. 

7.  Effects  of  external  agents  on  the  ciliary 
motion.  —  Steinbuch,  Purkinje,  and  Valentin 
allege  that  on  touching  the  parts,  or  giving 
them  a  gentle  shock  by  merely  striking  against 
the  object  plate  of  the  microscope,  the  motion 
is  rendered  brisker  when  it  has  become  languid, 
or  is  even  renewed  in  parts  where  it  has  ceased. 
They,  however,  attribute  more  importance  to 
this  fact  than  it  seems  to  deserve  ;  for  it  may  be 
doubted  whether  the  concussion  in  renewing 
the  vivacity  of  the  cilia  does  not  act  merely  by 
removing  obstacles  which  impede  their  play. 

Electricity  and  galvanism  produce  no  visible 
effect.  A  powerful  discharge  from  a  Leyden 
jar  was  made  to  pass  through  the  River-mussel 
by  Purkinje  and  Valentin  without  causing  any 
change  in  the  ciliary  motion.  Portions  of  the 
external  gills  of  the  Tadpole  were  subjected  by 
myself  to  the  same  experiment  and  with  a 
similar  result,  except  when  the  surface  was 
abraded,  which  occasionally  happened  with  a 
strong  discharge.  I  have  exposed  portions  of 
the  gill  of  the  River-mussel  while  viewed  with 
the  microscope,  to  the  influence  of  a  galvanic 
battery  of  twenty-five  pairs  of  three-inch  square 
plates,  charged  with  solution  of  salt,  without 
being  able  to  perceive  the  slightest  effect  on  the 
motion  of  the  cilia.  The  authors  above  men- 
tioned obtained  a  similar  result,  both  in  the 
Mussel  and  the  domestic  Fowl. 

The  effect  of  temperature  is  different  in  warm 
and  cold-blooded  animals.  In  the  former,  ac- 
cording to  Purkinje  and  Valentin,  the  motion 
stopped  on  exposure  to  a  temperature  of  43°  F. 
while  it  went  on  at  54°  F.  On  the  other  hand 
they  found  that  in  the  Fresh-water  Mussel  it  was 
not  affected  at  32°  F. ;  and  I  found  the  same 
to  be  true  of  the  Tadpole.  A  portion  of  the 
gills  of  the  River-mussel,  which  I  kept  for  five 
minutes  in  water  at  96°  F.  shewed  no  change. 

Acids,  saline  solutions,  and  other  substances 
applied  to  the  parts,  differ  in  their  effects  ac- 
cording to  the  kind  of  animals  submitted  to 
experiment.  Thus,  for  example,  fresh  water 
instantly  arrests  the  motion  in  the  Marine  Mol- 
lusca,  and  also  in  other  marine  animals  in 
which  I  have  tried  its  effect,  though  a  satu- 
rated solution  of  sea-salt  destroys  it  both  in 
salt  and  fresh-water  species.  Purkinje  and 


CILIA. 


635 


Valentin  state  the  effects  which  they  found  to 
result  from  the  application  of  various  sub- 
stances, but  erroneously  conceiving,  from  some 
preliminary  trials,  that  the  same  substance 
produced  the  same  effect  in  all  animals,  they 
confined  their  experiments  to  the  Fresh-water 
Mussel.  According  to  their  experiments,which 
were  made  with  a  great  many  different  sub- 
stances, most  of  the  common  acid,  alkaline, 
and  saline  solutions,  when  concentrated,  arrest 
the  motion  instantaneously;  dilution,  to  a 
degree  varying  in  different  substances,  pre- 
vents this  effect  altogether,  and  a  less  degree 
of  dilution  delays  it.  The  same  is  the  case 
with  alcohol,  aether,  aqua  laurocerasi,  sugar, 
and  empyreumatic  oil.  Kreosote,  muriate  of 
baryta,  sulphate  of  quinine,  infusio  pyrethri, 
and  muriate  of  veratria,  act  less  intensely.  Hy- 
drocyanic acid  and  watery  solutions  or  in- 
fusions of  belladonna,  opium,  capsicum,  ca- 
techu, aloes,  musk,  gum-arabic,  acetate  of 
morphia,  and  nitrate  of  strychnia,  produce  no 
effect  whatever.  They  accordingly  infer  that 
the  substances  affect  the  motion  only  in  so  far 
as  they  act  chemically  on  the  tissue. 

The  result  of  my  own  experiments  differs 
from  theirs  in  some  points.  In  the  River-mus- 
sel I  found  that  hydrocyanic  acid,  containing 
ten  per  cent,  of  pure  acid,  invariably  destroyed 
the  motion.  Solution  of  muriate  of  morphia, 
of  medicinal  strength,  also  arrested  the  motion 
in  the  Mussel,  but  not  in  the  Batrachian  larvae. 
The  motion  on  the  gills  of  these  larvae  also 
continues  unimpaired  in  water  deprived  of  air 
by  boiling,  or  distilled,  or  impregnated  with 
carbonic  acid;  a  sufficient  proof,  it  may  be 
remarked,  that  it  is  independent  of  the  che- 
mical process  of  respiration. 

In  regard  to  the  effect  of  animal  fluids,  the 
authors  already  mentioned  state  that  bile  ar- 
rests the  motion,  while  blood  has  the  property 
of  preserving  it  much  beyond  the  time  that  it 
lasts  in  other  circumstances,  at  least  in  verte- 
brated  animals ;  thus  it  continued  three  days 
in  a  portion  of  the  windpipe  of  the  Rabbit, 
which  had  been  kept  in  blood.  But  it  is  sin- 
gular that  blood  or  serum,  whether  of  Quadru- 
peds, Birds,  or  Reptiles,  has  quite  the  opposite 
effect  on  the  cilia  of  invertebrated  animals, 
arresting  their  motion  almost  instantaneously. 
Albumen  and  milk  also  possess  the  conserva- 
tive property,  though  in  a  less  degree. 

8.  Effects  of'  inflammation. —  Purkinje  and 
Valentin   excited    inflammation  artificially  in 
the  nose  and  vagina  of  rabbits,  and  are  in- 
clined to   conclude    from    their  experiments, 
which  however  are  not  numerous,  that  inflam- 
mation arrests  the  motion. 

9.  Of  the  power   by  which   the   cilia   are 
moved. — It   may  next  be  inquired    by   what 
means  or  by  what  power  the  cilia  are  moved  ; 
and,  in  particular,  whether  their  motion,  like 
other  visible  movements  in  the  animal  body, 
is  effected  by  muscular  action. 

Dr.  Grant,*  reflecting  that  in  the  Beroe  a 
vessel  conveying  water  runs  beneath  each  row 

*  Trans,  of  Zoological  Society  of  London, 
vol.  i.  p.  11. 


of  cilia,  and  that,  according  to  M.  Audouin, 
in  an  allied  genus  of  animals  the  water  enters 
the  cilia,  is  disposed  to  liken  the  motion  of 
the  cilia  to  that  of  the  feet  of  the  Echinoder- 
mata.  He  seems  accordingly  to  think  it  pro- 
bable that  the  cilia  are  tubular  organs,  which 
are  distended  and  protruded  by  the  injection 
of  water  into  them  from  elastic  tubes  running 
along  their  base,  in  which  the  water  is  conveyed 
by  successive  undulations. 

This  view,  however,  seems  scarcely  recon- 
cilable with  the  fact  that  the  motion  of  the 
cilia  continues  in  parts  separated  from  their 
connexion  with  the  rest  of  the  body,  portions 
so  small  that  not  more  than  two  or  three  cilia 
are  attached  to  them,  and  in  which  the  ope- 
ration of  the  supposed  undulating  tubes  can 
scarcely  be  conceived. 

Ehrenberg  states  that  in  the  Infusoria  he 
observed  that  the  cilia  were  bulbous  at  the 
root,  and  that  they  were  moved  by  small  mus- 
cles attached  to  the  bulb.  Purkinje  and  Va- 
lentin also  admit  the  existence  of  a  bulb,  and 
they  conceive  it  likely  that  the  cilia  are  moved 
either  by  muscular  substance  placed  within 
the  bulb,  or  by  certain  fibres  which  they  be- 
lieve they  have  discovered  in  the  adjacent 
tissue.  They  describe  these  fibres  as  existing 
in  the  substance  of  the  membranes  or  other 
parts  supporting  the  cilia,  being  situated  at 
the  surface,  straight  and  parallel,  and  ap- 
pearing to  be  connected  together  by  delicate 
cellular  tissue ;  and  they  think  it  highly  pro- 
bable that  they  are  of  a  muscular  nature. 

The  whole  phenomena  of  the  ciliary  motion 
seem  to  me  most  consistent  with  the  notion 
that  it  is  produced  by  muscular  action.  I 
must  confess,  however,  that  I  have  never  seen 
the  muscular  fibres  described,  nor  the  bulbs ; 
and  perhaps  the  cilia  are  not  moved  merely 
by  muscular  fibres  attached  to  their  base,  like 
the  whiskers  of  the  seal  and  cat,  but  may  con- 
tain muscular  substance  throughout  a  greater 
or  less  portion  of  their  length,  by  which  they 
can  be  bent  and  extended;  or  perhaps  they 
may  in  some  instances  be  bent  by  muscular 
fibres,  and  resume  their  original  shape  and 
position  by  virtue  of  their  elasticity. 

We  need  not  hesitate  to  admit  that  the 
ciliary  motion  is  the  result  of  muscular  action 
on  account  of  the  smallness  of  the  muscular 
apparatus  necessary ;  for  the  researches  of 
Ehrenberg  on  the  Infusoria  have  brought  to 
light  examples  of  complex  organization  on  as 
minute  a  scale  as  any  here  required.  Nor 
need  we  hesitate  on  account  of  the  great  ra- 
pidity of  action;  for  there  are  familiar  instances 
of  muscular  motions  of  equal  velocity.  The 
continuance  of  the  ciliary  motion  after  death 
and  in  parts  detached  from  the  rest  of  the 
body,  and  its  regularity  in  these  circumstances, 
are  appearances,  startling  at  first,  but  which, 
though  they  differ  in  degree,  may  be  fairly 
compared  with  those  produced  in  similar  cir- 
cumstances by  involuntary  muscular  action, 
and  may  be  attributed  to  the  same  cause. 
Thus  the  different  parts  of  the  heart,  which 
during  life  contract  in  a  certain  order  inde- 
pendently of  the  will,  continue  to  act  in  the 
2  T  2 


636 


CILIA. 


same  regular  order  for  a  time,  and  in  some 
animals  for  a  long  time,  after  death  or  sepa- 
ration from  the  body;  and  it  is  remarkable, 
although  perhaps  we  are  not  warranted  by  ob- 
servation to  lay  it  down  as  a  general  rule,  that 
there  is  a  correspondence  in  the  duration  of  the 
ciliary  motion  after  death  and  the  persistence 
of  muscular  irritability.  In  the  Tortoise,  for 
instance,  in  which  it  is  well  known  that  the  irri- 
tability of  the  heart  and  other  muscles  endures 
remarkably  long  after  death,  the  ciliary  motion 
is  also  of  extremely  long  continuance ;  while 
in  Mammalia  and  Birds,  the  ciliary  motion  and 
muscular  irritability  are  both  comparatively 
soon  extinguished. 

On  the  whole,  therefore,  without  laying  any 
stress  on  the  alleged  discovery  of  a  muscular 
apparatus  by  Ehrenberg  and  the  other  authors 
mentioned,  we  may  venture  to  conclude  that 
the  facts  known  respecting  the  motion  of  the 
cilia  are  all  reconcilable  with  the  opinion  that 
it  is  produced  by  muscular  contractility. 

10.  Strange  as  it  may  seem,  after  what  has 
been  said,   some  observers  maintain  that  the 
cilia    have  no   real   existence,    even  in  cases 
where  the  appearance  of  them   is  the   most 
perfect,  and  that  the  whole  is  an  optical  de- 
ception.     I   allude    particularly  to   Raspail ; 
according  to  him  the  water  which  quits  the 
respiring  surfaces  has,  in  consequence  of  the 
change  produced  in  it  by  respiration,  acquired 
a  different  density,  and   consequently  a  dif- 
ferent refractive  power  from  the  surrounding 
fluid ;   it  therefore    produces   the   appearance 
of  lines  or  streaks  at  the  surface  of  the  parts, 
which  streaks   are  the  supposed    cilia.     It  is 
scarcely  necessary  to  repeat  that  the  cilia  are 
seen  when   at  rest,  when   all  motion  of  the 
water  has  ceased,  and  that  they  are  evident  in 
circumstances  in  which  no  interchange  of  ma- 
terials can  take  place  between  the  tissue  and 
the  water  in  contact  with  it;  and  indeed,  after 
the  details  already  given,  it  is  needless  to  say 
more  in  refutation  of  this  view. 

1 1 .  Of  the  motion  caused  in  fluids  by  the 
cilia. — One  of  the  most  remarkable  characters 
of  the  motion   produced  in  water  and  other 
fluids  by  the  ciliary  action,  is  its  definite  di- 
rection, which,  except  in  some  of  the  Infusoria, 
appears  to   be  always  the  same  in  the  same 
parts ;  at  least  I  have  never  been  able  to  per- 
ceive any  exception  to  this  rule.     Appearances 
would  rather  lead   to   the  belief  that  in  the 
Infusoria  the  motion  of  the  cilia  is  under  the 
influence  of  the  will,  which  would  account  for 
this  and  other  possible  cases  of  exception. 

We  have  hitherto  taken  it  for  granted  that 
the  currents  in  the  water  are  owing  to  the 
mechanical  effect  of  the  moving  cilia,  without 
formally  adducing  proofs  in  support  of  the 
opinion;  but  at  the  same  time  the  details 
already  given  must  have  served  as  such.  The 
currents  cease  when  the  motion  of  the  cilia 
stops,  they  are  strong  and  rapid  when  it  is 
brisk,  and  feeble  when  it  languishes;  and 
though  there  are  modifying  circumstances  or 
perhaps  exceptions,  yet  in  general  the  mag- 
nitude and  velocity  of  the  current  seem  to  be 
proportionate  to  the  size  and  activity  of  the 


cilia.  It  is  true  that  while  doubts  remained 
as  to  the  existence  of  cilia  in  several  well- 
marked  instances  where  the  water  unequivo- 
cally received  its  motion  from  the  surface  over 
which  it  flowed,  and,  independently  of  any 
visible  contractions  of  the  animal  tissue,  there 
was  also  considerable  room  to  doubt  whether, 
even  in  the  cases  where  cilia  were  manifest, 
the  effect  of  these  organs  was  wholly  mecha- 
nical, and  whether  the  motion  of  the  water 
was  not  rather  due  to  some  peculiar  impulsive 
power  in  the  tissue,  differing  from  mechanical 
action.  But  more  extended  observation  has 
almost  wholly  removed  these  exceptions,  while 
it  has  considerably  increased  the  number 
of  conforming  instances,  insomuch  that  there 
seems  at  present  no  necessity  for  having  re- 
course to  any  other  explanation  of  the  motion 
of  the  fluids  than  that  it  is  produced  by  the 
action  of  the  cilia,  and  that  their  action  is  the 
result  of  muscular  contractility,  a  known  pro- 
perty of  animal  tissues. 

The  phenomena  of  the  ciliary  motion  seem 
therefore  of  themselves  to  afford  no  counte- 
nance to  the  notion  of  a  peculiar  impelling 
power  of  the  animal  tissue,  in  virtue  of  which 
fluids  are  visibly  moved  along  its  surface,  in- 
dependently of  impulse  communicated  to  them 
mechanically  by  cilia  or  by  contraction  of  in- 
closing solids ;  nor  am  I  aware  of  other  facts 
which  either  alone,  or  viewed  in  connexion 
with  the  former,  warrant  such  a  notion.  But 
as  some  physiologists  believe  in  the  existence 
of  such  a  power,  and  found  their  opinion,  at 
least  partly,  on  alleged  examples  -of  visible 
motions  of  fluids  in  organized  bodies,  pro- 
duced without  cilia  and  independent  of  con- 
traction of  the  solids,  it  may  not  be  amiss  here 
shortly  to  consider  the  principal  facts  which 
have  been  adduced  as  instances  of  this  kind. 

First,  Three  cases  have  been  already  men- 
tioned in  which  currents,  more  or  less  re- 
sembling those  produced  by  cilia,  take  place 
on  surfaces  on  which  cilia  have  not  been  de- 
tected; these  are  the  currents  in  the  Sponge, 
those  of  the  Tubularia  indivisa,  and  those 
within  the  stem  and  branches  of  Sertulariae. 
In  regard  to  the  Sponge,  it  is  true  that  cilia  have 
been  diligently  sought  for  and  without  success; 
still,  considering  the  difficulty  of  the  investi- 
gation, it  is  not  impossible  they  may  exist  in 
some  part  of  the  passages  through  which  the 
water  runs,  though  not  yet  discovered,  espe- 
cially as  the  ova  possess  evident  cilia.  With 
respect  to  the  currents  described  by  Mr.  Lister 
within  the  stem  of  the  Tubularia,  it  will  be 
seen,  on  referring  to  the  account  of  these,  that 
farther  observations  would  be  required  to  settle 
the  points  here  in  question,  viz.  whether  the 
floating  particles  receive  their  impulse  from  the 
surface  over  which  they  move  independently 
of  any  contraction  of  the  stem,  and  whether  or 
not  that  surface  is  covered  with  cilia.  To  de- 
cide these  points  satisfactorily  it  would  be 
necessary  to  lay  open  the  tube  and  make  trial 
of  detached  portions  of  the  tissue  as  in  other 
instances.  The  same  remark  is  in  a  great 
measure  applicable  to  the  currents  in  the  stem 
and  branches  of  Sertulariae.  Indeed  both 


CILIA. 


637 


instances  have  been  described  above  only  be- 
cause of  their  seeming  analogy  with  the  rest, 
but  further  investigation  is  still  required  to 
determine  their  true  nature.  Neither  these, 
therefore,  nor  the  Sponge  afford  unequivocal 
examples  of  the  peculiar  motion  of  fluids  al- 
luded to  taking  place  independently  of  cilia. 
Of  course  we  may  pass  over  without  notice 
the  cases  in  which  the  appearance  of  the 
moving  cilia  has  been  mistaken  for  a  circu- 
lating fluid,*  or  ascribed  to  other  causes  than 
the  real  one,  and  their  existence  erroneously 
denied. 

Secondly,  It  is  well  known  that  in  cold- 
blooded animals  the  blood  continues  to  move 
in  the  capillary  vessels  for  some  time  after  the 
heart  has  been  cut  out.  This  motion  for  the 
most  part  goes  on  at  first  steadily  from  the 
smaller  to  the  larger  vessels  in  the  arteries 
as  well  as  the  veins,  and  afterwards  becomes 
oscillatory.  Haller,  who  particularly  investi- 
gated the  phenomenon,  was  of  opinion  that  it 
could  not  be  attributed  to  contraction  of  the 
large  vessels,  to  gravitation,  nor  to  capillarity; 
he  therefore  attributed  it  to  some  unknown 
power  which  he  conceived  to  be  exerted  by  the 
solid  tissues  on  the  blood  and  also  by  the  glo- 
bules of  blood  on  each  other,  and  to  this 
power,  until  farther  investigation  should  eluci- 
date its  nature,  he  gave  the  name  of  attraction. 
The  same  opinion  or  a  modification  of  it  has 
been  taken  up  by  succeeding  physiologists ; 
accordingly  many  maintain  the  existence  of  a 
peculiar  propulsive  power  in  the  coats  of  the 
capillary  vessels  different  from  contractility,  or 
that  the  globules  of  blood  are  possessed  of  the 
power  of  spontaneous  motion.  Among  others, 
Dr.  Alison  has  adopted  and  extended  this  view 
in  so  far  as  he  regards  the  motion  of  the  blood 
in  the  capillaries  as  one  of  the  effects  produced 
by  what  he  calls  vital  attraction  and  repulsion, 
powers  which  he  conceives  to  be  general  attri- 
butes of  living  matter,  or  at  least  to  manifest 
themselves  in  other  processes  of  the  living 
economy  besides  the  capillary  circulation. 

The  motion  in  question  has  certainly  not 
been  as  yet  satisfactorily  accounted  for  by  re- 
ferring it  to  the  operation  of  known  causes. 
At  the  same  time  we  can  scarcely  admit  that 
the  influence  of  such  causes  has  been  wholly 
avoided  in  the  experiments  in  which  the  phe- 
nomenon has  been  observed.  It  is  not  im- 
possible, for  example,  that  a  certain  degree  of 
agitation  may  be  occasioned  in  the  blood  by 
the  elastic  resilience  of  the  vessels  reacting  on 
it,  after  the  distending  force  of  the  heart  has  been 
•withdrawn.  The  necessity  of  the  case  there- 
fore, though  great,  seems  scarcely  such  as  alone 
to  warrant  the  assumption  of  a  peculiar  attrac 
tive  or  repulsive  power  acting  on  the  blood  at 
sensible  distances,  of  whose  existence  in  the 
animal  economy  we  have  as  yet  no  other  evi- 
dence. It  may  be  remarked,  finally,  in  regard 
to  the  phenomenon  alluded  to,  that  it  cannot 
properly  be  termed  a  continuance  of  the  circu- 
lation, for  the  blood  does  not  necessarily  pre- 

*  As  by  Baker,  Guillot,  and  others. 


serve  its  original  course,  nor  indeed  any  con- 
stant direction.  (See  CIRCULATION.) 

Thirdly,  In  several  plants  motions  have  been 
observed  in  the  fluids  which  are  contained  in 
their  cells  or  vessels  in  determinate  directions, 
and  seemingly  independent  of  any  contraction 
of  the  parietes  of  the  containing  cavities.  The 
best  known  example  of  this  is  in  the  Cham. 
Its  jointed  stem  consists  of  a  series  of  elon- 
gated cells,  which  contain  a  clear  fluid  with 
globules  suspended  in  it.  The  globules  are 
moved  up  one  side  of  the  cell  and  down  the 
other  in  continual  circuit.  No  contraction  can 
be  perceived  in  the  parietes  of  the  cells,  which 
are  indeed  of  a  rigid  texture,  and  this  myste- 
rious movement  has  therefore  been  ascribed  to 
some  unknown  and  invisible  impelling  power. 
It  is  doubtful,  however,  whether  the  motion 
can  go  on  unless  the  cell  is  entire,  the  experi- 
ments of  different  observers  on  this  point  being 
contradictory,  and  it  certainly  has  never  been 
shewn  that  separated  portions  of  the  tissue 
continue  to  excite  the  motion.  In  this  state  of 
knowledge  on  the  subject  we  can  scarcely 
admit  this  or  similar  motions  of  vegetable 
juices  as  unequivocal  examples  of  the  opera- 
tion of  an  impulsive  power  of  the  kind  referred 
to;  and  even  on  the  contrary  supposition  it 
does  not  follow  that  such  a  power  exists  in 
animals. 

On  the  whole  therefore,  from  what  has  been 
said  regarding  the  several  examples  adduced, 
we  may  conclude  that  they  do  not  afford  une- 
quivocal evidence  of  visible  motions  being 
produced  in  fluids  in  the  animal  body,  inde- 
pendently of  contractions  of  containing  solids 
or  of  the  action  of  cilia;  and,  consequently, 
that  viewed  in  reference  to  the  ciliary  motion, 
they  form  no  adequate  reason  for  doubting  that 
the  fluid  is  moved  mechanically  by  cilia. 

I  may  conclude  this  article  by  observing, 
that  though  the  general  existence  of  the  ciliary 
motion  in  the  Animal  Kingdom  is  already  suffi- 
ciently established,  yet  many  particular  in- 
stances of  it  must  still  remain  to  be  found  out, 
especially  in  invertebrated  animals  ;  and  who- 
ever has  opportunities  and  inclination  to  cul- 
tivate this  field  of  inquiry  will  find  his  labour 
rewarded  by  much  curious  and  interesting 
discovery. 

BIBLIOGRAPHY.— (The  works  more  especially  &• 
serving  of  attention  are  marked  with  an  asterisk.} — 
*Ant.  de  Heide,  Anatome  mytuli,  &c.  8vo.  Ainst. 
1684.  Swammerdam,  Biblia  Naturae,  foJ.  Leidae, 
1737.  *Leeuwenhoek,  Opera,  4to.  Delph.  et  Lugd. 
Bat.  1695-1719.  *Baker,  Of  microscopes,  &c, 
8vo.  Lond.  1785.  Hales,  Haemastaticks,  3d  edit. 
8vo.  Lond.  1769  Ellis,  Hist.  Nat.  des  Corallines, 
4to.  La  Haye,  1756,  (a  translation  from  the  Eng- 
lish, with  the|author's  additions).  Roesel,  Insecten- 
belustigungeri,  vol.  iii.  4to.  Niirnberg,  1755.  *Spal- 
lanzani,  Opuscules  de  Physique,  8vo.  Pavie,  1787. 
*0.  F.  Mutter,  Hist,  vermium  terrestrium  et  fluvia- 
tilium,  4to.  Hafnias,  1773,  and,  Animalcula  Infu- 
soria, 4to.  Hafniae,  1786.  *Cavolini,  Memorie  per 
servire  alia  storia  dei  polipi  marini,  4to.  Napoli, 
1785;  translated  into  German  by  W.  Sprengel, 
Niirnb.  1813.  Poli,  Testacca  utriusque  Siciliae, 
fol.  Parmae,  1792.  Stiebel,  Lyranai  Stagnalis 
anatome,  4io.  G'ott.  1815,  and  in  Mecfcel'l  Deuischcs 
Archiv.  fur  die  Physiologic,  13d  i.  and  ii.  Ehrman, 


633 


CIRCULATION. 


in  Abhandl.  der  kbnigl.  Akad.  der  Wissensch.  zu 
Berlin  fur  1816-1817.  *Gruithuisen,  in  Salzb.  Med. 
Chir.  Zeitung,  1818,  Bd  iv.  ;  Nov.  Act.  Acad. 
Caes.  Leop.  vol.  x.  G.  R.  Treviranus,  Vermischte 
Schriften,  4to.  Bd  iii.  Bremen,  1820.  Hugi,  in 
Isis  for  1823.  *Carus,  Von  den  aussern  Lebens- 
bedingungen  der  weiss-und  kaltbluetigen  Thiere, 
4to.  Leipz.  1824;  Nov.  Act.  Ac.  Caes.  Leop. 
vols.  xiii.  and  xvi.  Fleming,  in  Mem.  of  Wer- 
nerian  Society,  vol.  iv.  *Huschke,  in  Isis  for 
1826.  *R.  Grant.,  in  Edin.  Phil.  Journal,  Edin. 
New  Phil.  Journ.,  Edin.  Journal  of  Science,  and 
Trans,  of  Zoological  Society.  Sir  E.  Home,  Phil. 
Trans.  1827.  *Raspail,  Mem.  de  la  Soc.  d'Hist. 
Nat.  de  Paris,  4to.  vol.  iv.  1827;  Chimie  Or- 
ganique,  8vo.  Paris,  1833.  Meyen,  Isis  for  1828. 
E.  H.  Weber,  in  Meckel's  Archiv.  1828.  Fr.  Esch- 
scholz,  System  der  Acalephen,  4to.  Berlin,  1829. 
Dutrochet,  in  Annales  des  Sc.  Nat.  t.  xv.  1828. 
*W.  Sharpey,  in  Edin.  Med.  and  Surg.  Journal, 
vol.  xxxiv.  July,  1830.  Guillot,  in  Magendie 
Journal  de  Physiologie,  xi.  1831.  *Ehrenberg, 
Ueber  Infusorien,  in  Abhandl.  der  k.  Acad.  der 
Wissensch.  zu  Berlin  fur  1830  and  1831,  Muller's 
Archiv.  i.  1834.  R.  Wagner,  Isis  for  1832.  Jo. 
Mutter,  Handbuch  der  Physiologie,  Bd  i.  8vo. 
1833.  H.  Rathke,  in  Dorpater  Jahrbucher,  &c. 
Bd  i.  1833.  *Jos.  J.  Lister,  in  Phil.  Trans.  1834. 
*J.  E.  Purkinje  fy  G.  Valentin,  in  Muller's  Archiv. 
Bd  i.  translated  in  Dublin  Journ.  of  Med.  and 
Chem.  Science  for  May,  1835,  and  in  Edin.  New 
Phil.  Journ.  vol.  xix.  July,  1835 ;  also,  by  the 
same  authors,  Commentatio  Physiologica  de  Phe- 
nomeno  Motus  vibratorii  continui,  &c.  4to.  Wratislav. 
1835,  (the  only  systematic  treatise  on  the  subject.) 
(  W.  Sharpey.) 

CIRCULATION  (in  Physiology),  ( Circu- 
latio,  Circulus,  Circuitus  Sanguinis  ;  Fr.  Cir- 
culation du  Sang;  Germ.  Blutlauf;  Ital.  Cir- 
colazione  del  Sangue;)  designates  in  its  more 
extensive  signification  the  course  through  or- 
ganised beings  of  their  nutritious  fluid;  as 
limited  to  man  and  the  higher  orders  of  ani- 
mals, the  course  of  the  blood  from  the  heart 
to  the  most  minute  vessels,  and  from  these  back 
to  the  heart. 

By  modern  writers  on  physiology  the  circu- 
lation of  the  blood  is  generally  included  under 
the  nutritive  functions,  because  one  of  the  most 
important  purposes  served  by  the  motion  of 
this  fluid  through  the  various  textures  and 
organs  of  the  body  is  the  supply  of  those  new 
ingredients  which  are  necessary  to  carry  on  the 
process  of  growth  and  the  changes  of  nu- 
trition. A  very  slight  acquaintance  with  ani- 
mal physiology  teaches  us,  however,  that  the 
function  of  circulation  has  another  very  im- 
portant and  immediate  use,  viz.  the  support 
of  that  condition  of  the  textures  and  organs 
which  is  necessary  to  enable  them  to  exercise 
their  vital  properties.  It  was  on  account  of 
the  apparent  necessity  of  a  constant  supply  of 
blood  for  the  support  of  the  animal  powers, 
that  Galen  placed  circulation,  along  with  re- 
spiration, among  the  vital  functions. 

In  the  following  article  it  is  intended  to  de- 
scribe more  particularly  the  course  of  the 
blood  in  the  human  body  and  the  powers  by 
which  it  is  moved,  and  also  to  state  the  general 
facts  ascertained  regarding  the  function  of  cir- 
culation in  other  animals. 

For  the  sake  of  clearness  it  will  be  neces- 
sary to  divide  the  subject  into  several  dc 


partments.  The  first,  of  these  will  compre- 
hend a  description  of  the  course  of  the  blood 
in  man;  the  second  of  its  course  in  animals. 
In  the  third  will  be  considered  the  phenomena 
presented  by  the  blood  during  its  motion,  the 
properties  of  the  organs  in  which  it  circulates, 
and  the  powers  by  which  it  is  propelled  ;  and 
in  the  fourth  will  be  mentioned  the  more  im- 
portant circumstances  connected  with  the  other 
functions  which  modify  the  circulation. 

The  term  circulation  applied  by  its  cele- 
brated discoverer,  Harvey,  to  the  motion  of  the 
blood,  is  sufficiently  expressive  of  the  general  fact 
that  this  fluid,  or  the  greater  part  of  it  at  least, 
in  being  carried  through  the  body,  moves  in  a 
circular  course,  or,  that  in  performing  its  jour- 
ney through  the  body,  the  blood  always  re- 
turns to  the  same  place  from  which  it  set  out. 
The  term  is  equally  applicable  to  the  func- 
tion by  which  a  supply  of  nutritious  fluids  is 
kept  up  in  the  lowest  animals,  in  which  a  pro- 
gressive motion  of  a  fluid  of  the  nature  of 
blood  takes  place,  as  well  as  in  the  highest ;  for 
in  nearly  the  whole  of  them  there  is  a  central 
part  of  the  circulatory  organs,  which  forms  the 
rallying  point,  as  it  were,  of  the  rest,  from 
which  the  blood  begins  its  course  and  to  which 
it  is  brought  back,  in  a  longer  or  shorter  period 
of  time,  after  having  passed  through  the  dif- 
ferent organized  parts. 

I.  COURSE  OF  THE  BLOOD  IN  MAN. 

The  organs  of  circulation  consist  of  the  heart, 
arteries,  veins,and  capillary  vessels.  We  refer  the 
reader  to  the  articles  on  these  different  organs  for 
all  details  relative  to  their  anatomical  structure. 

In  man  and  warm-blooded  animals  there 
are  two  passages  through  the  interior  of  the 
heart,  through  each  of  which  a  stream  of  blood 
is  propelled  at  the  same  time,  so  that  the  heart 
is  alternately  receiving  and  giving  out  a  certain 
quantity  of  blood  upon  each  side. 

The  two  auricles  serve  as  receiving  cavities 
for  the  blood  which  is  constantly  flowing  into 
the  heart  from  the  veins  or  those  vessels  which 
have  the  office  of  returning  blood  to  the  centre 
of  the  circulation.  By  the  contraction  of  the 
muscular  parietes  of  the  auricles,  the  blood  is 
propelled  from  these  cavities  into  the  ventricles, 
which,  in  their  turn,  contract  with  force  and 
thus  propel  their  contents  into  the  arteries,  or 
those  vessels  which  serve  to  transmit  blood 
outwards  from  the  centre  of  the  circulatory 
organs.  The  auricles  and  ventricles  of  the 
opposite  sides  acting  simultaneously,  and  the 
size  of  these  cavities  on  the  right  and  left  sides 
of  the  heart  being  nearly  equal,  the  quantity 
of  blood  which  is  made  to  pass  through  each 
of  them  at  one  and  the  same  time  must  also  be 
nearly  equal. 

The  cavities  on  the  left  side  of  the  heart  are 
adapted  to  propel  the  blood  into  those  arteries 
which  are  subservient  to  the  nutrition  of  the 
body,  while  those  on  the  right  side  of  the  heart 
send  the  blood  to  the  lungs  for  the  purposes 
of  respiration.  The  construction  of  the  heart 
and  the  connection  of  its  parts  with  the  arte- 
ries and  veins  are  such  that  the  whole  of  that 


CIRCULATION. 


639 


blood  which  has  served  the  purposes  of  nu- 
trition, and  the  other  uses  for  which  the  blood 
is  destined  throughout  the  body,  on  being  re- 
turned to  the  heart,  is  directed  by  the  cavities 
on  the  right  side  of  that  organ  to  the  lungs,  and 
made  to  pass  through  them  before  returning 
to  the  left  side  of  the  heart  to  repeat  its  course 
through  the  nutritive  vessels  of  the  body. 

In  all  those  animals  in  which  there  exists  a 
disposition  of  the  heart  and  bloodvessels  such 
as  that  described,  the  circulation  is  said  to  be 
double,  because  the  blood  is  moved  in  two 
circles  at  once,  and  the  respiration  is  said  to 
be  complete,  because  the  whole  of  that  blood 
which  has  passed  through  the  nutritive  vessels 
of  the  body  is  subjected  to  the  respiratory 
action  of  air  in  the  lungs. 

The  blood  returned  from  the  lungs  of  a 
bright  red  colour,  or  arterial  blood,  on  being 
expelled  from  the  left  ventricle  (Jig.  312,  H) 

Fig.  312* 


Circulation  in  Man. 

*  In  all  the  figures  relating  to  the  circulation  in 
different  animals  the  same  letters  indicate  corres- 
ponding parts  as  follows  : 

Iff  the  heart  or  the  common  ventricle  j  h,  the 
common  auricle  ; 

A,  the  aorta  or  trunk  of  the  systemic  arteries  ; 

a,  its  branches  ;  a*,  the  carotids. 

Vf  the  great  systemic  veins  or  vena  cava  infe- 
rior j  v,  its  branches ;  «*,  the  vena  cava 
superior  ;  c,  the  capillary  vessels  ; 

P,  the  pulmonary  artery ;  p,  the  pulmonary 
vein  ; 

B,  the  branchial  artery ;  b,  the  branchial  vein ; 
D,  the  ductus   arteriosus  ;    d,  ductus  venosus  ; 

f,  foramen  ovale ; 
U,  umbilical  arteries  ;  «,  umbilical  vein  j 


by  the  muscular  contraction  of  that  cavity, 
passes  into  the  aorta  or  great  artery  of  the 
system  (A),  and  is  distributed  in  various  pro- 
portions to  all  parts  of  the  body  by  the 
branches  of  the  aortic  trunk  (a)  and  their  in- 
finitely minute  ramifications.  The  smallest 
arteries  lead,  by  an  intermediate  set  of  minute 
tubes  to  which  the  name  of  capillary  vessels  is 
given,  into  the  systemic  veins  (u),  all  of  which 
(the  veins  of  the  intestinal  canal  excepted)  join- 
ing gradually  together  into  larger  and  fewer 
branches,  form  at  last  the  great  trunks  of  the 
superior  and  inferior  venae  cavae  (  F,  v*),  which 
carry  back  to  the  centre  of  the  circulation  the 
whole  of  the  blood  that  had  passed  from  the 
left  ventricle  into  the  aorta. 

In  passing  from  the  arteries  to  the  veins  - 
through  the  capillary  vessels,  the  properties  of 
the  arterial  blood  are  changed ;  its  colour  is 
altered  from  bright  scarlet  to  dark  purple, 
it  expends  some  of  its  substance  in  the  nou- 
rishment of  the  textures,  and  a  considerable 
quantity  of  its  thinner  part  transudes  through 
the  small  vessels,  constituting  the  lymph  that 
is  taken  up  by  the  absorbent  vessels.  The 
venous  or  dark  blood,  as  it  approaches  the 
heart  upon  its  return,  has  its  composition  fur- 
ther changed  by  its  admixture  with  the  chyle 
or  imperfectly  formed  blood,  which  is  the  pro- 
duct of  digestion,  and  which  is  poured  along 
with  the  lymph  from  the  thoracic  duct  into 
the  great  veins  of  the  head  and  superior  ex- 
tremities. 

By  the  changes  thus  produced  in  its  com- 
position, &c.,  the  venous  blood  which  returns 
to  the  heart  is  rendered  unfit  for  nutrition, 
until  it  has  been  acted  upon  by  the  atmos- 
pheric air  in  the  lungs,  which  restores  to  it  its 
bright  red  colour  and  arterial  composition  and 
properties. 

The  great  systemic  veins  are  therefore  con- 
nected with  the  right  side  of  the  heart  (If), 
and  the  stream  of  venous  blood  brought  by 
them  to  the  right  auricle  (h'\  next  issues  from 
the  heart  by  the  pulmonary  artery  (P),  into 
which  it  is  propelled  by  the  contraction  of  the 
right  ventricle  (H')  as  it  passes  through  that 
cavity.  The  minute  branches  of  the  pulmo- 
nary arteries  and  veins  ( P,  p),  and  the  capil- 
lary vessels  by  which  they  communicate  with 
one  another,  are  wholly  distributed  on  the 
membrane  lining  the  air-cells  of  the  lungs. 
In  passing  through  these  vessels  then,  the 
venous  blood  is  exposed  to  the  action  of  the  at- 
mospheric air  contained  in  the  pulmonary  cells ; 
and,  after  having  acquired  arterial  properties, 
is  returned  to  the  centre  of  the  circulation  by 

/,  arteries  of  the  intestine  or  alimentary  canal ; 

»,  the  coeliac  artery  ; 
L,  vena  port<fi  j    I,    hepatic  vein ;    I*,   hepatic 

artery  ; 
K,  advehent  renal  veins  ;    k,  renal  veins  ;   k*, 

renal  artery. 

In  those  instances  in  which  the  parts  are  double, 
those  on  the  right  side  are  distinguished  by  the 
accentuation  of  the  letters  indicating  them,  thus 
P'  right  pulmonary  artery,  P  left  ditto. 

We  beg  to  remind  the  reader  that  most  of  these 
figures  are  merely  plans,  and  that  strict  anatomical 
accuracy  is  not  to  be  looked  for  in  them. 


640 


CIRCULATION. 


the  pulmonary  veins  (/?).  The  left  auricle  (A) 
receives  the  newly  arterialized  blood  from  the 
pulmonary  veins,  and  transmits  it  to  the  left 
ventricle  (-BTJ,  from  which  it  is  ready  to  start 
again,  when  the  ventricle  contracts,  on  the 
same  course  as  has  just  been  described. 

In  this  double  circulation,  the  path  which 
the  blood  traverses  in  passing  from  the  left  to 
the  right  side  of  the  heart  through  the  aortic 
arteries  and  the  corresponding  veins,  has  been 
'  called  the  greater  or  systemic  circulation  :  and 
the  route  of  the  blood  from  the  right  to  the  left 
side  of  the  heart  through  the  pulmonary  arte- 
ries and  veins  has  been  termed  the  Lesser  or 
pulmonic  circulation.  The  names  of  pulmonic 
and  systemic,  indicating  tfye  parts  of  the  body 
in  which  each  of  these  circulations  respectively 
occurs,  are  on  the  whole  preferable  to  the  cor- 
responding terms  of  lesser  and  greater. 

There  is  still  one  part  of  the  course  of  the 
blood  to  be  mentioned,  viz.  that  of  the  venous 
blood  of  the  principal  abdominal  viscera 
through  the  liver,  or  what  has  been  termed  the 
system  of  the  vena  portse. 

The  blood  supplied  by  the  coeliac  and  me- 
senteric  arteries  (I,  i)  to  the  abdominal  viscera 
1  is  not  returned  directly  to  the  heart  by  their 
corresponding  veins,  as  occurs  in  other  parts 
of  the  body.  The  veins  of  the  stomach  and 
intestinal  canal,  of  the  spleen,  pancreas,  me- 
sentery, omenta,  and  gall-bladder,  unite  to- 
gether below  the  liver  into  one  large  vessel 
(£),  the  trunk  of  the  vena  portae,  which 
branches  out  again  and  distributes  to  the  liver 
by  its  ramifications  the  whole  of  the  venous 
blood  coming  from  the  above-mentioned  organs. 
The  blood  of  the  vena  portse,  being  joined  in 
the  minute  branches  by  that  of  the  hepatic 
artery  (/*),  passes  into  the  smallest  ramifica- 
tions of  the  hepatic  veins,  by  the  principal 
trunks  of  which  (/),  the  venous  and  arterial 
blood  circulated  through  the  liver  is  carried  to 
the  inferior  vena  cava,  and  thus  reaches  at  last 
the  right  side  of  the  heart. 

Proofs  of  the  circulation.-*— After  this  brief 
outline  of  the  course  which  the  blood  takes 
through  the  circulatory  organs  in  man  and 
warm-blooded  animals,  it  may  be  proper  to 
introduce  an  enumeration  of  those  circum- 
stances which  are  generally  adduced  as  af- 
fording the  most  satisfactory  "  proofs  of  the 
circulation"  or  evidence  that  the  blood  pursues 
the  paths  above  detailed. 

As  proofs  of  the  circulation,  besides  those 
derived  from  the  connection  of  the  different 
orders  of  great  vessels  with  the  cavities  of  the 
heart  to  which  they  are  respectively  attached, 
may  be  mentioned — 

1st.  The  structure  and  disposition  of  the 
auriculo-ventricular  valves  of  the  heart,  and 
semilunar  valves  of  the  aorta  and  pulmonary 
artery,  which  admit  of  the  passage  of  blood 
from  the  auricles  to  the  ventricles,  and  from 
the  latter  cavities  to  the  great  arteries,  but  not 
in  a  reverse  direction. 

2nd.  The  mechanism  of  the  valves  of  the 
systemic  veins  which  allow  of  the  motion  of 
fluid  only  in  the  direction  towards  the  heart. 

3rd.  The  fact  that  when  a  ligature  is  applied 


to  an  artery,  or  any  other  impediment  opposed 
to  the  free  passage  of  blood  through  if,  the 
vessel  becomes  dilated  on  the  side  next  the 
heart,  while  the  application  of  a  ligature  to  the 
trunk  of  a  vein  is  followed  by  a  turgescence  of 
the  vessel  beyond  the  place  where  the  obstruc- 
tion occurs. 

4th.  That  on  opening  one  of  the  larger  arteries, 
blood  issues  in  a  jet  from  the  end  next  to  the 
heart  at  the  time  of  every  contraction  of  that 
organ,  and  that  in  general  no  blood  flows  from 
the  orifice  of  the  remote  part  of  the  artery: 
and  that  on  opening  a  vein  the  converse  is  ob- 
served, the  blood  issuing  freely  in  a  continued 
stream  from  the  remote  part,  but  none  proceed- 
ing from  the  part  of  the  vein  adjoining  the 
heart. 

5th.  That  the  passage  of  the  blood  from  the 
arteries  to  the  veins  in  the  small  or  capillary 
vessels  has  been  observed  by  means  of  the 
microscope  in  transparent  parts  of  animals, 
and,  though  it  has  not  been  seen  in  man,  we  are 
entitled  from  the  general  analogy  in  the  struc- 
ture of  the  organs  of  circulation  to  infer  that 
the  same  passage  occurs  in  the  human  body. 

6th.  That,  by  mechanical  arrangements, 
fluids  may  easily  be  made  to  pass  in  the  dead 
body  through  the  whole  course  of  the  double 
circulation,  but  not  in  a  direction  different 
from  that  which  the  blood  has  been  stated  to 
pursue. 

7th.  That  by  the  operation  of  transfusion, 
the  blood  of  one  animal  may  be  made  to  circu- 
late through  the  heart  and  vessels  of  another, 
by  connecting  together  the  bloodvessels  (whe- 
ther arteries  or  veins)  of  the  two  animals,  in 
such  a  manner  that  the  course  in  which  the 
blood  is  directed  by  the  action  of  the  heart  of 
the  animal  from  which  the  blood  is  derived  is 
that  of  the  natural  circulation  in  the  animal  into 
which  it  is  introduced. 

8th.  The  phenomena  presented  by  the  circu- 
lation of  the  blood  in  various  diseased  condi- 
tions of  the  heart  and  bloodvessels  may  be  ad- 
duced as  affording  additional  illustration  of  the 
natural  course  of  the  blood,  by  pointing  out  the 
effect  of  morbid  obstructions  and  other  varieties 
in  different  parts  of  the  circulatory  organs. 

Course  of  the  blood  in  the  foetus  before  birth. 
— The  double  circulation  just  described  is  the 
course  performed  by  the  blood  from  the  time 
of  birth  during  the  whole  of  life. 

The  circulation  of  the  blood,  however,  begins 
at  a  very  early  period  of  foetal  life;  but  the 
difference  in  the  mode  in  which  respiration  is 
effected  in  the  child  so  long  as  it  is  contained 
in  the  uterus,  induces  a  modification  in  the 
course  of  the  blood  to  which  we  shall  now 
advert. 

There  being  no  inhalation  of  air  into  the 
lungs  of  the  foetus,  the  blood  is  sent  only  in 
small  quantity  to  these  organs,  and  does  not 
undergo  in  them  any  change  of  properties.  A 
considerable  portion  of  the  blood  of  the  foetus 
passes  out  of  its  body  through  the  umbilical 
cord  (Jig.  313,  U,  u)  into  the  placenta  of  the 
uterus.  The  minutely  divided  foetal  vessels  are 
bathed  by  the  blood  of  the  mother  contained  in 
the  placental  sinuses,  and,  though  no  direct 


CIRCULATION. 


641 


Fig.  313. 


Foetal  circulation  seen  from  behind. 

continuity  of  tube  exists  between  the  maternal 
and  foetal  vessels,  the  blood  of  the  child  seems 
to  undergo  a  respiratory  alteration,  or  a  certain 
degree  of  arterialization,  in  being  brought  into 
near  proximity  with  the  maternal  blood. 

The  blood  of  the  foetus,  after  passing  through 
the  minute  ramifications  of  the  umbilical  arte- 
ries ( V,  U)  in  the  placenta,  returns  by  the 
umbilical  vein  (u)  into  its  body. 

The  umbilical  vein  carries  part  of  its  blood 
directly  by  the  ductus  venosus  (d)  to  the  vena 
cava  inferior,  and  part  is  distributed  by  the 
branches  of  the  vena  portse  ( L),  with  which 
the  umbilical  vein  unites,  through  the  sub- 
stance of  the  liver,  and  is  then  conveyed  by 
means  of  the  hepatic  veins  (/)  into  the  general 
current  of  the  returning  blood. 

The  right  auricle  of  the  heart  (//),  therefore, 
receives  not  only  the  blood  which  has  circu- 
lated through  the  body  of  the  foetus,  but  also 
that  which  has  passed  through  the  placenta, 
consequently  a  mixture  of  venous  and  arterial 
blood ; — the  blood  in  the  superior  vena  cava 
(v*)  being  entirely  venous,  that  in  the  inferior 
vena  cava  (  V)  being  mixed.  The  blood  which 
is  brought  to  the  right  auricle  is  in  much 
greater  quantity  in  the  foetus  before  birth  than 
in  the  child  which  has  breathed  air ;  a  part  of 
this  blood  passes  from  the  right  into  the  left 
auricle  (A)  by  the  foramen  ovale  (/)  in  the  sep- 
tum auricularum,  and  it  would  appear  that  it  is 
chiefly  the  blood  from  the  inferior  vena  cava 
which  takes  that  course. 

The  rest  of  the  blood  entering  the  right 
auricle  takes  the  same  route  as  in  the  adult, 
viz.  into  the  right  ventricle  (H'),  and  thence 
into  the  pulmonary  artery,  but,  as  very  little 
blood  is  sent  to  the  collapsed  lungs,  a  passage 


of  communication  is  established  in  the  fetus 
from  the  pulmonary  artery  into  the  descending 
aorta  through  the  ductus  arteriosus  (D),  and 
thus  the  greater  mass  of  the  blood,  which  in 
the  adult  would  have  proceeded  to  the  lungs,  is 
in  the  foetus  immediately  transmitted  to  the 
aorta  (A). 

From  the  disposition  of  the  Eustachian  valve, 
it  is  believed  that  nearly  the  whole  of  the  blood 
of  the  inferior  vena  cava  passes  from  the  right 
to  the  left  auricle  through  the  foramen  ovale, 
while  the  blood  brought  from  the  head  and 
superior  extremities  (parts  which  are  compara- 
tively large  in  the  foetal  condition)  passes 
through  the  right  side  of  the  heart.  The  as- 
cending aorta,  rising  from  the  left  ventricle, 
delivers  almost  all  the  blood  expelled  by  the 
contraction  of  that  cavity  into  the  carotid  and 
subclavian  arteries,  while  the  ductus  arteriosus 
passing  between  the  trunk  of  the  pulmonary 
artery  and  the  descending  aorta  directs  the 
blood  which  passes  through  the  right  ventricle 
to  the  lower  regions  of  the  body.  In  this 
manner  the  upper  regions  of  the  body  are  sup- 
plied with  the  most  arterialized  part  of  the 
blood  from  the  left  side  of  the  heart  and  aorta, 
while  the  purely  venous  blood  is  propelled 
from  the  right  ventricle  through  the  pulmonary 
artery  and  ductus  arteriosus  into  the  descend- 
ing aorta,  and  consequently  into  the  lower  part 
of  the  body,  and  by  the  umbilical  vessels  to  the 
placenta. 

The  foramen  ovale  in  the  septum  of  the  au- 
ricles, the  ductus  arteriosus  passing  from  the 
pulmonary  artery  to  the  aorta,  the  ductus  ve- 
nosus leading  from  the  umbilical  vein  to  the 
vena  cava  inferior,  and  the  umbilical  vein  and 
arteries  are  the  structural  peculiarities  of  the 
foetal  circulating  organs.  These  passages  are  all 
closed  up,  and  the  umbilical  vessels  obliterated 
at  the  navel  after  aerial  or  pulmonic  respiration 
is  established  at  birth.* 

II.     COURSE    OF    THE    BLOOD    IN   VARIOUS 

ANIMALS. 

We  now  leave  for  the  present  the  history  of 
the  circulation  in  man,  in  order  to  give  a  brief 
sketch  of  the  varieties  of  this  function  in  other 
animals,  the  study  of  which  is  calculated  to 
throw  considerable  light  upon  some  of  the  pro- 
cesses of  the  human  economy,  and  to  illustrate 
the  anatomical  and  physiological  relations  of 
the  circulatory  and  respiratory  organs.f 

It  has  been  shewn  that  a  regular  and  pro- 
gressive circulation  of  the  nutritive  fluids  occurs 
in  those  animals  only  in  which  the  aeration  of 
the  blood  is  performed  by  a  separate  and  dis- 

*  Sabatier,  Mem.  de  1'Acad.  An  8.  Kilian, 
Kreislauf  im  Kinde,  &c.  Karlshruhe,  1826.  Bur- 
dach's  Physiologic,  &c.  vol.  ii.  Jeffray,  Pecu- 
liarities of  the  Foetal  Circulation.  Glasgow,  1834. 

t  In  the  following  view  of  the  comparative  phy- 
siology of  the  circulation,  besides  the  different 
works  referred  to  under  the  separate  heads,  we  have 
been  guided  chiefly  by  the  following,  viz.  the  works 
of  Cuvier,  Home,  Meckel,  Blumenbach,  Trevira- 
nus,  Carus,  and  R.  Wagner ;  Roget's  Bridgewater 
Treatise,  and  the  excellent  chapter  upon  this  sub- 
ject by  J.  Miiller  in  Burdach's  Physiologic,  vol.  iv. 
and  in  his  Handbuch  der  Physiologie,  vol.  i. 


642 


CIRCULATION. 


tinct  respiratory  apparatus ;  and  that,  amid  the 
immense  varieties  of  form  which  the  circulatory 
organs  present  in  different  animals,  the  course 
of  the  blood  bears  a  more  close  relation  in  all 
to  the  form  of  their  respiratory  apparatus  than 
to  any  other  part  of  their  organization.  This 
general  law  of  the  relation  between  circulation 
and  respiration,  satisfactorily  established  by  the 
extended  researches  of  modern  comparative 
anatomists,  receives  farther  confirmation  from 
many  facts  connected  with  the  performance  of 
these  functions  in  the  adult  human  body,  and 
is  illustrated  in  a  peculiar  manner  by  the  re- 
markable changes  which  take  place  in  the  cir- 
culatory and  respiratory  organs  of  the  child 
before  and  after  birth. 

In  treating  of  the  varieties  in  the  course  of 
the  blood  in  different  animals,  we  are  at  once 
freed  from  any  embarrassment  regarding  the 
order  proper  to  be  pursued,  by  the  circumstance 
that  the  form  of  the  circulatory  organs  consti- 
tutes one  of  the  principal  bases  upon  which  the 
modern  classification  of  animals  is  founded; 
so  that,  in  following  the  zoological  arrange- 
ment, we  take  the  order  best  adapted  for  our 
present  purpose.  As  our  object  in  giving  this 
sketch  is  principally  to  illustrate  the  structure 
and  functions  of  the  human  organs  of  circula- 
tion, we  shall  begin  with  the  consideration  of 
the  course  of  the  blood  in  those  animals  which 
most  nearly  resemble  man ;  and  trace  the  varie- 
ties in  this  function,  as  far  as  our  knowledge 
permits,  through  the  descending  series  of  the 
animal  chain. 

1.  Course  of  the  blood  in  warm-blooded 
animals. — In  Mammalia  and  Birds,  the  form 
of  the  organs  of  circulation  and  the  course  of 
the  blood  are  essentially  the  same  as  in  Man, 
for  in  all  of  these  animals  the  heart  contains 
four  distinct  cavities, — two  auricles  and  two 
ventricles,  and  there  is  consequently  a  double 
circulation  and  a  complete  respiration. 

Some  considerable  varieties  in  the  form  of 
the  circulatory  organs,  which  seem  to  have  a 
relation  to  peculiarities  in  habits  or  mode  of 
life,  occur  in  certain  mammiferous  animals, 
such  as  the  Cetacea,  Amphibious  C&rnivora, 
the  Sloths,  Hybernating  Animals,  &c.;  but  we 
shall  not  at  present  enter  upon  the  considera- 
tion of  these  varieties,  because  they  do  not 
amount  to  any  deviation  from  the  type  or 
general  plan  of  construction  of  the  human 
organs  of  circulation,  and  consequently  are  not 
accompanied  by  any  material  difference  in  the 
course  of  the  blood,  but  seem  rather  to  have 
the  effect  merely  of  modifying  the  quantity  of 
blood  sent  to  particular  organs,  or  of  influen- 
cing its  velocity  and  force.* 

In  the  organs  of  circulation  of  the  various 
tribes  of  Birds,  we  observe  the  same  remarka- 
ble uniformity  of  structure  which  pervades  the 
rest  of  their  internal  organization. 

It  may  be  remarked  that,  as  in  Birds  a  cer- 
tain respiratory  action  takes  place  in  the  large 
air-cells  distributed  over  the  trunk  of  the  body, 
and  as  the  pulmonary  vessels  seem  in  most 
birds  not  to  extend  to  these  cells,  but  to  be 

*  Sec  p.  678. 


confined  to  the  thoracic  lungs,  the  blood  con- 
tained in  the  small  branches  of  the  systemic 
arteries  and  veins,  ramifying  upon  the  lining 
membrane  of  the  air-cells,  must  be  made  to 
undergo  some  respiratory  alteration  of  its  com- 
position ;  but  we  have  not  as  yet  obtained  the 
means  of  judging  accurately  of  the  extent  to 
which  such  a  respiratory  change  may  be  effect- 
ed in  the  vessels  of  the  systemic  circulation, 
nor  how  far  the  minute  branches  of  the  pulmo- 
nary vessels  may  in  some  instances  be  pro- 
longed from  the  lungs  into  the  air-cells.* 

Very  frequent  anastomoses  take  place  among 
the  veins  of  Birds.  We  may  here  mention  one 
of  these  which  induces  an  important  modifica- 
tion in  the  portal  circulation.  By  means  of  a 
communicating  branch  which  passes  from  the 
united  caudal,  hemorrhoidal,  and  iliac  veins  to 
the  vena  portae,  the  blood  of  the  viscera  of  the 
abdomen  and  of  the  posterior  part  of  the  body 
may  flow  indifferently  either  into  the  vena  cava 
inferior  or  the  vena  portae,  a  disposition  which 
may  have  for  its  object  to  prevent  congestion  of 
blood  in  the  parts  from  which  these  veins  pro- 
ceed .f 

A  still  more  remarkable  modification  of  the 
venous  circulation  in  Birds  was  supposed  to 
exist  by  Professor  Jacobson  of  Copenhagen, 
consisting  in  the  distribution  of  branches  of  the 
vena  cava  inferior  to  the  interior  of  the  kidneys 
and  their  subdivision  in  these  organs,  in  the 
same  manner  as  the  vena  portae  subdivides  in 
the  liver.  Such  veins  transmitting  venous 
blood  to  the  kidneys,  in  the  manner  of  a  vena 
portse,  have  been  ascertained  by  Professor 
Jacobson,|  and  are  admitted  by  others  making 
subsequent  researches,  to  exist  in  Reptiles  and 
Fishes ;  but  Nicolai§  has  shewn  that  the  lower 
veins,  described  by  Jacobson  in  Birds  as  ven<e 
advehentes  of  the  kidney,  do  not  differ  from  the 
other  branches  of  the  vena  cava,  and  serve  to 
carry  away  from  these  organs,  like  the  superior 
renal  veins  of  Birds  and  the  renal  veins  of 
Quadrupeds,  the  venous  blood  derived  from 
the  arteries. 

Course  of  the  blood  in  cold-blooded  vertebra- 
ted  animals. — Of  cold-blooded  vertebrated  ani- 
mals, some,  as  the  adult  Batrachia,  Chelonia, 
Ophidia,  and  Sauria,  breathe  air  by  means  of 
lungs,  while  the  rest,  as  the  young  Batrachia, 
the  Protean,  and  Siren-like  Reptiles  and  Fishes, 
are  constant  inhabitants  of  water,  and  breathe 
the  air  contained  in  that  medium  by  means  of 
gills  or  branchiae.  Of  the  aquatic  cold-blooded 
animals,  Fishes  breathe  by  gills  only,  while 
the  aquatic  Reptiles  or  Amphibia  are  furnished 
with  lungs  as  well  as  gills  during  the  greater 
part  of  their  aquatic  life. 

*  See  the  article  Aves,  p.  330. 

t  It  is  a  remarkable  fact  that  there  have  been 
found,  between  the  hemorrhoidal  veins  in  Man  and 
some  branches  of  the  vena  portae,  anastomoses  by 
small  branches,  which  correspond  in  some  respects 
with  the  disposition  of  the  veins  referred  to  above. 
These  anastomoses  were  known  to  Haller,  and  are 
lately  described  by  Retzius.  See  his  Researches  in 
Tiedemann's  and  Treviranus'  Zeitschrift,  vol.  v.  1. 

$  Meckers  Archiv.  vol.  iii.  p.  147.  Ediiu  Med. 
and  Sure.  Journ.  vol.  xix.  p.  78. 

$  Isis,  1826,  p.  414. 


CIRCULATION. 


643 


Reptiles. — The  structure  and  functions  of 
the  circulatory  organs  in  Reptiles  form  a  sub- 
ject of  great  interest  on  account  of  the  nume- 
rous varieties  which  they  exhibit  in  different 
orders  and  genera,  for  in  this  respect  the  class 
of  Reptiles  may  be  said  to  present  to  us  an 
anatomical  analysis  of  the  circulatory  and  re- 
spiratory organs,  and  to  constitute  a  gradually 
simplifying  series  of  forms,  the  observation  of 
which  enables  us  to  trace  in  the  most  clear  and 
interesting  manner  an  analogy  and  correspon- 
dence between  the  forms  of  these  organs  in 
warm-blooded  animals  and  in  fishes,  which, 
but  for  the  study  of  their  structure  in  reptiles, 
must  very  probably  ever  have  remained  hidden 
from  our  view. 

In  Fishes  the  heart  consists  of  one  auricle 
and  one  ventricle,  and  a  single  current  of  blood 
only  passes  through  it.  The  structure  of  the 
heart  is  very  similar  in  some  of  the  Batrachia 
breathing  by  gills,  but  among  other  reptiles, 
we  find  a  gradual  transition  in  the  form  and 
structure  of  the  heart  from  that  just  mentioned 
as  peculiar  to  animals  with  aquatic  respiration, 
to  the  double  heart  possessed  by  warm-blooded 
and  air-breathing  animals. 

Among  the  Reptiles  provided  with  lungs  and 
breathing  air,  some,  as  the  Sauria,  Ophidia,  and 
Chelonia,  have  the  ventricular  part  of  the  heart 
partially  divided  into  two  cavities  (Jig.  314, 

Fig.  314. 


Heart  of  Lacerta  ocellata. 

H,  H'J  which  correspond  in  structure,  relative 
situation,  and  connections  to  the  right  and  left 
ventricles  of  the  heart  of  warm-blooded  ver- 
tebrata;  the  anterior  or  right  compartment 
')  giving  off  chiefly  the  pulmonary  (  P )•>  the 
eft  or  posterior  (H),  the  systemic  arteries  (A). 
In  the  others,  viz.  the  Batrachia  and  Protean 
reptiles,  the  ventricle  forms  a  single  cavity 
(Jigs.  317  and  318,  H),  and  gives  origin  to 
one  large  artery  only  (A),  so  that  the  pulmo- 
nary and  systemic  arteries  derive  their  blood 
from  the  same  trunk.  In  all  of  these,  how- 
ever, the  auricle  is  double,*  so  that  the  venous 

*  The  auricle  of  the  Batrachia  was  generally  de- 
scribed as  single  until  the  discovery  of  the  left  or 
pulmonary  auricle  in  the  Frog  and  Toad  by  Dr. 
John  Davy.  Mr.  Owen  has  shewn  this  to  be 
the  case  also  in  the  Newt  andt  protean  Reptiles  j 


blood  from  the  system  and  the  arterial  blood 
from  the  lungs  are  received  into  separate  auri- 
cular compartments  of  the  heart,  and  are  sub- 
sequently mingled  together  in  the  common 
ventricular  cavity.  In  the  Heart  of  the  Croco- 
dile of  the  Nile,  Cuvier*  has  described  three 
compartments,  one  of  which  corresponds  to  the 
left,  the  other  two  to  the  right  ventricle,  the 
septum  between  the  right  and  left  sides  being 
incomplete.  The  heart  of  the  Crocodilus  Lu- 
cius is  described  by  Hentz,  Meckel,f  and 
others  as  consisting  of  two  ventricles,  between 
which  the  septum  is  quite  complete,  so  as  to 
permit  of  no  direct  passage  of  fluid  from  one 
side  to  the  other,  possessing  therefore  in  this 
respect,  the  same  structure  as  the  heart  of  warm- 
blooded animals.  In  those  of  the  above-men- 
tioned reptiles  in  which  the  septum  is  so  nearly 
complete  as  to  divide  the  ventricle  into  two 
separate  compartments  communicating  by  a 
small  orifice,  the  arterial  and  venous  blood  are 
believed  to  be  kept  separate  from  one  another 
by  a  valvular  apparatus.  Among  the  rest  of  the 
Saurian,  Ophidian,  and  Chelonian  Reptiles,  in 

Fig.  315. 


Heart  of  Common  Tortoise. 

all  of  which  the  septum  of  the  ventricular  part 
is  less  complete  than  in  the  Crocodile,  there  is 
considerable  variety  in  the  extent  to  which  the 
division  of  the  cavity  is  effected  by  the  septdm. 
In  a  few  of  them  the  septum  projects  so  little 
into  the  ventricular  cavity  that  it  cannot  be 
supposed  to  divide  to  any  extent,  or  to  prevent 
the  complete  mixture  of  the  two  kinds  of  blood 
propelled  from  the  opposite  auricles. 

In  the  Crocodile,  and  in  those  Reptiles  in 
which  the  ventricular  septum  is  nearly  com- 
plete, the  circulation,  so  far  as  regards  the 
heart  at  least,  may  be  considered  as  almost 
double,  or  the  same  as  in  warm-blooded  ani- 

Zool.  Trans,  1834,  p.  213.  See  also  Martin  St. 
Ange's  Plate  of  the  Circulation,  and  M.  Weber, 
Beitr.  zur  Anut.  und  Physiol.  Bonn,  1832. 

*  Lc9ons,  vol.  iv.  p.  221. 

t  Vcrgleich.  Anatomic,  vol.  v.  p.  231. 


644 


CIRCULATION. 


rnals,  that  is  to  say,  the  arterial  blood  returning 
from  the  lungs  to  the  left  auricle  (fig.  314,  h) 
is  directed  entirely  into  the  arteries  of  the 
system  (A)  from  the  left  compartment  of  the 
ventricle  ( H ),  and  the  venous  blood  brought 
back  to  the  right  auricle  (h')  by  the  venae 
cavae  (Vv*)  is  directed  wholly  into  the  pul- 
monary vessels  (P)  by  the  right  ventricular 
compartment  (H'). 

Fig.  316. 


Lacerta  ocellata. 

In  all  Reptiles,  however,  the  descending  aorta 
is  formed  by  the  union  of  two  branches,  the 
right  and  left  aortic  arches  (figs.  314,  315,  316, 
and  317,  A',  A) ;  the  right  corresponds  with  the 
systemic  aorta  of  birds,  and  rises  from  the 
left  ventricular  compartment,  the  left  arch  joins 
the  right  on  the  back,  and  leads  generally 
from  the  right  ventricular  cavity  into  the 
descending  aorta.  The  arteries  of  the  head 
and  upper  extremities  (fig.  314,  a*J,  arising 
from  the  right  aorta  (A'},  which  corres- 
ponds with  the  aorta  of  birds,  and  is  con- 


nected with  the  left  ventricular  compartment, 
are  supplied  with  highly  arterialized  blood 
proceeding  directly  from  the  lungs.  The  left 
arch  of  the  aorta  (A),  being  connected  on 
the  other  hand  with  the  right  ventricular  com- 
partment ( H'),  obtains,  like  the  pulmonary 
artery,  venous  blood  from  the  right  auricle;  and 
consequently  the  common  trunk  of  the  aorta, 
formed  by  the  union  of  the  right  and  left  aortic 
arches,  must  carry  to  the  posterior  parts  of  the 
body  a  mixture  of  arterial  and  venous  blood.* 
It  may  be  remarked,  however,  that  in  the  Turtle 
and  some  Lizards  the  left  aortic  arch  does  not 
join  the  right  upon  the  back  until  after  it  (the 
left)  has  given  off  the  great  creliac  or  rather 
visceral  artery,  which  supplies  the  whole  of  the 
alimentary  canal  and  digestive  organs  with  ve- 
nous blood  (fig.  315,  I).  The  left  aorta  is  thus 
much  diminished  in  size  before  it  sends  its  com- 
paratively small  communicating  branch  to  the 
right.f  From  this  disposition  of  the  parts,  it  is 
obvious  that  in  these  animals  the  abdominal 
viscera  must  receive  the  greater  part  of  the 
venous  blood  brought  from  the  right  side  of  the 
heart  by  the  left  aortic  arch,  while  the  right 
aortic  arch  which  gives  the  carotid,  brachial,  ver- 
tebral, intercostal,  and  other  arteries  must  carry 
to  the  parts  it  supplies  in  the  first  part  of  its 
course  nearly  pure  arterial  blood,  and,  after 
it  is  joined  by  the  left,  blood  which  contains 
a  small  proportion  only  of  the  dark  or  venous 
kind.  In  the  Turtle,  some  Lizards  and  Ser- 
pents again,  the  arterial  and  venous  blood  must 
be  mixed  in  the  ventricular  cavity  though  par- 
tially divided ;  the  two  streams  of  blood  pro- 
pelled into  the  aortic  and  pulmonary  vessels 
must  therefore  be  nearly  of  the  same  kind,  and 
thus  a  part  only  of  the  blood  which  is  sent  to 
the  lungs  is  made  to  undergo  a  respiratory 
change.  In  some  of  the  Chelonia,  the  exis- 
tence of  ductus  arteriosi,  leading  from  the  pul- 
monary artery  on  each  side  into  the  arch  of  the 
aorta,  insures  a  still  more  complete  mixture  of 
the  arterial  and  venous  blood .J 

In  most  of  the  adult  Batrachia  the  ventricle 
(fig.  317,  H),  being  single  and  giving  rise  to 
one  arterial  trunk  only  (A),  the  pulmonary 
arteries  ('P',  P)  derive  their  blood  from  the 
great  systemic  aortic  trunk  of  which  they  are 
branches;  one  coming  off  from  each  of  the 
aortic  arches  which  unite  to  form  the  descend- 
ing aorta.  The  venous  blood  returning  from 
the  system  (  V  v*}  to  the  right  auricle,  is  mixed 
in  the  common  cavity  of  the  ventricle  with  the 
arterial  blood  returning  to  the  left  auricle  by 
the  pulmonary  veins  (p\  and  this  mixed  blood 
being  propelled  into  the  aortic  bulb  is  distri- 
buted in  part  to  the  system  and  in  part  to  the 
lungs.  In  these  animals  then,  only  a  small 
quantity  of  a  mixed  blood  is  exposed  to  the 
action  of  the  air  in  the  lungs,  which,  from  the 
simplicity  of  their  structure,  offer  only  a  con- 

*  In  the  Crocodile,  the  left  branch  coming  from 
the  right  ventricle  is  small  and  very  short. 

t  See  Bojanus'  beautiful  Anat.  Monography  of 
the  Tortoise. 

t  In  this  respect,  t"as  well  as  in  the  mode  of 
origin  of  the  left  aortic  arch,  the  Tortoise  and  Tur* 
tie  differ  from  one  another. 


CIRCULATION. 


645 


Fig.  317. 


Frog. 

fined  surface  for  the  distribution  of  the  pulmo- 
nary capillary  vessels. 

In  the  aquatic  Reptiles  having  gills,  such  as 
the  larvae  of  the  Frogs  and  Salamanders  in  their 
transitory  conditions,  and  the  Protean  animals, 


Tig.  318. 


Proteus  Mexicanus  (Axolotl). 


which  are  very  similar  to  them,  but  do  not  un- 
dergo, so  far  as  is  known,  any  further  metamor- 
phoses, the  branchial  organs  are  formed  by  an 
extension  or  minute  subdivision  of  branches  of 
the  aortic  trunk,  supported  upon  the  arches  of 
the  hyoid  bones.  In  all  of  these  Reptiles,  the 
ventricle  consists  of  a  single  cavity  (Jig.  318, 
H ),  which  propels  its  blood  into  the  bulb  or 
commencement  of  the  aortic  trunk  (A  ).  The 
aortic  trunk  divides  into  two  branches,  each  of 
which  subdivides  again  into  three  or  four  ves- 
sels upon  each  side  of  the  neck.  These  vessels 
(  B),  passing  round  the  gullet  or  upper  part  of 
the  alimentary  canal  in  the  form  of  lateral 
arches,  unite  again  together  behind,  to  form  the 
descending  aorta.  The  branchial  apparatus  of 
the  animals  now  under  consideration  is  formed 
entirely  upon  these  lateral  arches  of  the  aortic 
trunk.  In  the  larva  of  the  Salamanders,  in 
the  Proteus,  Axolotl,  Menobranchus,  and 
Siren,*  the  small  branches  of  each  gill  are 
formed  by  the  minute  subdivision  of  a  loop  of 
vessel  prolonged  from  the  outer  part  of  three  of 
the  arches  on  each  side  into  leafed  processes  of 
the  cuticular  system  attached  to  the  hyoid  ar- 
ches (B,  6). 

The  larva  of  the  Frog  has,  in  the  earliest 
stage  of  its  existence,  gills  of  the  same  kind  as 
those  just  described;  but  in  its  more  advanced 
condition  these  external  gills  disappear,  and 
the  larva  of  the  frog  breathes  by  internal  gills 
more  resembling  those  of  fishes  than  the  ex- 
ternal branchiae  of  the  Newt  or  Proteus.  The 
gills  of  the  tadpole  of  the  Frog  are  covered 
by  the  skin,  arid  consist  of  a  great  number  of 
small  leaflets,  receiving  the  minutely  subdi- 
vided loops  of  vessel  given  off  for  some  way 
along  each  of  the  four  vascular  arches  as  they 
pass  round  the  neck  along  the  cartilaginous 
hoops  of  the  hyoid  bone.  The  vascular  arches 
are  double  in  that  part  of  their  course  where 
they  are  connected  with  the  gill,  the  blood 
being  transmitted  from  one  branch  to  the  other 
in  passing  through  the  leaflets  of  the  gill. 

In  the  larvae  of  the  Batrachia,  from  a  very  early 
period  of  their  existence,  as  well  as  in  the  Pro- 
tean Reptiles,  there  are  lungs  which  seem  to 
be  used  as  adjuvant  respiratory  organs,  for  they 
are  generally  filled  by  the  animal  with  air  from 
time  to  time.  These  lungs,  more  or  less  per- 
fectly developed  in  different  kinds  of  Protean 
Reptiles,  and  at  different  stages  of  the  existence 
of  the  Batrachian  larvae,  all  receive  a  pulmo- 
nary vessel  from  the  vascular  arch  of  the  aorta 
which  is  nearest  the  heart,  whether  this  arch  is 
connected  with  a  branchial  apparatus  or  not. 

In  all  these  animals  the  anatomical  relations 
and  the  mode  of  development  of  the  blood- 
vessels of  the  gills  proves  distinctly  their  re- 
turning vessels  to  be,  as  much  as  those  which 
conduct  the  blood  into  them,  branches  of  the 
arterial  system ;  but  the  lungs  on  the  other 
hand,  however  rudimentary,  are  almost  always 
furnished  with  proper  pulmonary  veins  which 
lead  to  the  auricle  of  the  heart. 

The  following  is  the  course  which  the  blood 
takes  in  this  interesting  class  of  animals.  The 

*  We  omit  the  consideration  of  the  Amphiuma, 
Menopoma,  and  Coecilia. 


646 


CIRCULATION. 


heart  (A,  H )  receives  the  whole  venous  blood 
of  the  body  by  the  right  auricle,  and  a  small 
quantity  of  arterial  blood  from  the  lungs  by 
the  left.  These  two  kinds  of  blood,  mixed 
together  in  the  common  ventricle,  proceed 
from  thence  into  the  aortic  bulb  and  its 
branches  (A,  B,  b}.  In  the  larva  of  the  Sala- 
mander and  Protean  Reptiles,  a  part  of  the 
blood  is  sent  by  pulmonary  vessels  to  the 
lungs,  from  which  it  is  returned  by  the  pul- 
monary veins  to  the  heart ;  a  part  passes  di- 
rectly round  the  arches,  and  gains  the  descend- 
ing aorta ;  the  greatest  quantity  passes  out  into 
the  gills,  and  after  being  arterialized  returns  to 
be  mixed  with  that  in  the  aorta,  so  that  a 
mixed  blood  must  permeate  all  the  vessels  of 
the  systemic  circulation.  In  the  Siren,  accord- 
ing to  Cuvier  and  Owen,  the  whole  blood  goes 
at  once  to  the  gills,  from  the  want  of  any  com- 
municating twigs  across  the  root  of  these 
organs.  It  is  interesting  to  remark  that  the 
arteries  of  the  head  and  upper  extremities  (a) 
are  not  given  off  by  the  aortic  arches  until 
after  they  are  joined  by  the  returning  branchial 
vessels,  a  disposition  which  is  in  some  respect 
similar  to  what  we  find  in  higher  Reptiles,  and 
which  seems  to  have  for  its  object  the  supply 
of  a  more  pure  arterial  blood  to  the  cerebral 
organ. 

In  the  larva  of  the  Frog,  the  course  of  the 
blood  is  very  similar  to  that  of  Fishes.  The 
whole  of  the  venous  blood  propelled  through 
the  heart  is  sent  into  the  gills,  and  is  made  to 
pass  through  them  before  reaching  any  other 
part.  From  the  posterior  parts  of  the  first 
arches  are  given  off  the  vessels  of  the  head,  the 
second  form  the  right  and  left  roots  of  the  de- 
scending aorta,  and  the  fourth  are  continued 
upon  the  lungs  in  the  form  of  a  pulmonary 
artery.  There  is  however  also  in  the  larva  of 
the  Frog  a  short  anastomosis  between  the  out- 
going and  returning  artery  of  each  of  the  gills, 
which  allows  of  a  direct  passage  of  some  blood 
round  the  arches  of  the  aorta. 

In  the  Protean  Reptiles  and  larva  of  the 
Batrachia  a  greater  quantity  of  blood  is  sent  to 
the  respiratory  organ  than  occurs  in  the  adult 
Frog  or  Salamander. 

Portal  circulation  in  Reptiles. — In  the  class 
of  Reptiles  there  are  two  lesser  venous  circula- 
tions besides  those  already  described ;  the  one, 
similar  to  the  portal  circulation  of  warm-blooded 
animals,  belongs  to  the  liver;  the  other,  which 
does  not  appear  to  occur  either  in  Birds  or 
Mammalia,  belongs  to  the  kidneys.  According 
to  Jacobson,  who  was  the  £rst  to  point  out  the 
existence  of  veins  carrying  blood  to  the  kidneys 
in  the  Amphibia,  and  the  later  researches  of 
Nicolai  and  others,  there  are  two  principal  ves- 
sels which  carry  back  blood  from  the  posterior 
parts  of  the  body,  viz.  the  anterior  abdominal, 
and  the  inferior  renal  veins.  These  two  vessels 
are  formed  by  the  union  of  the  iliac,  caudal, 
posterior  cutaneous,  pelvic,  visceral,  abdominal, 
and  umbilical  veins;  and  in  most  Reptiles,  ex- 
cepting the  Ophidia,  the  renal  and  portal  vessels 
proceeding  from  the  posterior  parts  of  the  body 
arise  together.  In  some  Reptiles  the  whole  of 
the  blood  returning  from  the  posterior  parts  of 


the  body  is  divided  between  the  portal  veins  of 
the  liver,  and  the  venae  advehentes  of  the  kidney ; 
in  others  a  part  is  also  sent  into  the  abdominal 
vena  cava.  The  inferior  renal  or  advehent 
veins  of  the  kidneys  (Jigs.  316,  317,  and  318, 
jfiC)  carry  venous  blood  to  these  organs,  and 
distribute  it  minutely  through  their  substance. 
It  is  removed  from  thence  and  returned  into 
the  great  circulation  by  the  revehent  or  superior 
renal  veins  (/c)  which  lead  into  the  vena  cava.* 
The  anterior  abdominal  vein  (fig.  316,  u)  is  the 
same  to  which  Bojanus  has  given  the  name  of 
umbilical  in  the  Tortoise,  in  which  class  of  ani- 
mals it  is  of  very  large  dimensions,  and  receives 
not  only  the  venous  blood  from  the  posterior 
extremities  and  shell,  but  also  some  from  the 
anterior  extremities.  The  persistence  of  those 
umbilical  veins  which  proceed  from  the  large 
urinary  bladder  in  many  of  the  adult  reptiles  is 
a  fact  of  some  interest,  because  it  points  out  a 
resemblance  between  the  permanent  distribu- 
tion of  the  vessels  in  these  reptiles  and  the 
foetal  condition  which  we  find  in  the  higher 
animals,  and  likens  the  bladder  of  the  scaly 
Reptiles,  as  well  as  of  the  Batrachia  in  which 
during  foetal  life  no  allantoid  membrane  is  ever 
formed,  rather  to  an  allantoid  receptacle  than 
to  a  proper  urinary  bladder. 

Fishes. — In  fishes  there  is  no  vestige  of  a 
pulmonary  organ,  and  the  respiration  is  wholly 
effected  by  means  of  the  gills.  The  branchial 
apparatus  of  fishes  is  internal  or  covered,  like 
that  of  the  larva  of  the  frog ;  it  is  placed  on 
the  cervical  part  of  the  alimentary  canal,  and 
is  formed  by  the  fine  subdivisions  of  aortic 
arches  (Jig.  319,  A,  B,  b},  which  are  prolonged 
into  the  fringed  or  leafy  processes  of  the  hyoid 
branchial  arches.  The  respiratory  organ  is 
thus  placed  in  this  class  in  the  course  of  the 
arterial  circulation.  The  venous  blood  from 
.  the  body  generally,  and  from  the  liver,  enters 
the  single  auricle  (A)  through  the  great  sinus 
(V),  and  is  wholly  propelled  into  the  arterial 
bulb  by  (A)  the  single  ventricular  cavity  (H). 
No  systemic  arteries  come  from  the  aortic  bulb, 
but  this  vessel  carries  by  the  arches  into  which 
it  divides  (B),  the  whole  of  the  venous  blood 
into  the  gills.  The  number  of  these  arches 
subdividing  and  ramifying  in  the  gills  varies 
in  different  fishes.  In  a  few,  as  the  Lophius, 
there  are  only  three  on  each  side.  In  most 
osseous  fishes  there  are  four.  In  the  Skates 
and  Sharks  there  are  five.  In  the  Lampreys 
there  is  the  greatest  number  known,  namely, 
six  or  seven. 

The  blood,  after  having  undergone  arteria- 
lization  in  the  gills,  is  not  returned  to  the  heart, 
but  proceeds  directly  through  the  branches  of 
the  aorta  (j^g.319*,  b  6,  A)  to  different  organs. 
The  force  of  the  heart  acts  therefore  through  the 
whole  of  the  capillary  system  of  the  gills  (be ), 
and  continues  to  propel  the  arterialized  blood 

*  It  must  be  remarked  that  Meckel,  who  appears 
to  have  examined  the  distribution  of  the  above  men- 
tioned vessels  with  great  care,  denies  entirely  the 
advehent  function  of  the  lower  veins  of  the  kidneys 
both  in  fishes  and  reptiles,  considering  all  the  veins 
of  the  kidney  as  revehent.  Vergleich.  Anat.  B.V. 
S.  201  and  253. 


CIRCULATION. 


647 


Fig.  319. 


Fish. 

through  the  branches  of  the  aorta  (A)  in  the 
various  parts  of  the  systemic  circulation.  Dr. 
Marshall  Hall*  and  J.  Mullerf  have  observed  a 
dilated  contractile  part  of  the  caudal  vein  in  the 
tail  of  the  Eel,  to  which  Dr.  Hall  has  applied 
the  name  of  caudal  heart,  which  may  assist 
in  promoting  the  flow  of  blood  in  the  caudal 
branches  of  the  vena  cava. 

The  position  and  anatomical  relation  of  the 
heart  of  fishes  with  the  bloodvessels  as  well 
as  other  parts  shew  that  it  corresponds  to 
the  whole  heart  of  higher  animals,  and  that 
the  arterial  vessel  which  receives  the  whole 
of  the  fish's  blood  from  the  ventricle  may 
strictly  be  considered  as  the  commencement 
of  an  aorta  entirely  destitute  of  any  pul- 
monary branches.  Although  there  is  no  dis- 
tinct right  ventricle  to  propel  the  blood  to 
a  pulmonary  organ,  and  the  whole  of  the 
blood  issuing  from  the  heart  is  sent  directly  to 
the  gills,  there  is  not  on  this  account  any  suf- 
ficient reason  for  considering,  as  some  have 
done,  the  heart  of  the  fish  as  corresponding  to 

*  Essay  on  the  Circulation  of  the  Blood,  p.  170. 
Loncl.  1831. 
f  Handbuch  der  Physiol.  vol.  i. 


the  pulmonary  or  right  cavities  of  the  heart  iu 
warm-blooded  animals,  for  we  have  seen  that 
in  some  of  the  reptiles  when  they  have  gills, 
the  blood  is  driven  into  these  organs  through 
the  aorta  or  systemic  trunk.  The  branchial 
arteries  in  fishes,  as  in  reptiles,  are  therefore 
branches  of  the  great  aortic  trunk,  and  the 
returning  vessels  on  the  posterior  side  of  the 
arches,  or  branchial  veins  as  they  are  called, 
are  as  much  of  an  arterial  nature  both  in  their 
structure  and  relations  as  the  anterior  vessels 
or  branchial  arteries  are.  When  these  return- 
ing vessels  unite  together  on  the  back  to  form 
the  descending  aorta,  it  is  not  necessary  there- 
fore to  suppose  them  to  undergo  a  change  from 
the  venous  to  the  arterial  structure.  So  far 
then  as  general  structure  and  relative  position 
are  concerned,  the  heart  of  the  fish  corres- 
ponds to  the  whole  heart  of  warm-blooded 
animals,  and  not  to  one  or  other  set  of  its 
cavities.  Nor  does  the  contemplation  of  its 
function  or  uses  in  the  circulation  induce  us 
to  modify  this  view,  for  it  is  manifest  that  the 
heart  of  the  fish,  as  it  serves  to  propel  the 
blood  through  the  gills  into  the  vessels  of  the 
system,  and  as  the  branchial  vessels  may  be 
considered  as  belonging  to  the  aortic  system, 
acts  at  once  as  a  branchial  and  a  systemic 
heart.* 

We  have  abstained  from  entering  at  this 
place  into  the  detail  of  those  remarkable 
changes  formerly  alluded  to,  which  the 
circulatory  and  respiratory  systems  and  the 
systemic  and  branchial  or  pulmonary  circu- 
lations undergo  during  the  development  of  the 
young  of  animals,  although  these  afford  the 
most  direct  proofs  of  the  justness  of  the  view 
now  taken.  Under  the  head  of  Ovum  we 
shall  have  a  more  fitting  opportunity  of  ex- 
plaining these  fully.  Suffice  it  for  the  present 
to  say  that  the  heart  of  the  highest  warm- 
blooded animals  passes,  during  the  progress  of 
its  development  at  different  periods  or  stages, 
through  the  same  general  outline  of  various 
forms  which  that  organ  retains  permanently  in 
the  adults  of  fishes  or  different  reptiles ;  and 
that  the  aortic  arches  and  a  semblance  of  a 
branchial  apparatus  connected  with  them  is 
not  confined  to  those  animals  which  necessarily 
employ  gills  for  a  time  as  respiratory  organs, 
but  are  to  be  found  also  in  the  foetus  of  the 
scaly  reptiles,  birds,  and  mammalia  in  the 
early  stages  of  their  existence.  The  ductus 
arteriosus,  double  in  birds  and  single  in  mam- 
malia, is,  we  may  remark,  the  last  of  those 
transitory  structures  which  remains  in  the 
foetus. 

Portal  circulation  of  fishes. — In  fishes,  as 
in  reptiles,  both  the  liver  and  kidneys  have 
venous  blood  distributed  to  them  by  the  sub- 
division within  these  organs  of  veins  (L&tK) 
from  the  abdominal  viscera  and  posterior  parts 
of  the  body.  The  vena  portae  of  the  liver 
consists  generally  of  veins  from  the  stomach, 
intestinal  canal,  spleen,  pancreas,  and  some- 
times from  the  genital  organs,  swimming  blad- 

*  Blainville,  Sur  la  Degradation  du  Coeur,  &c. 
Bull,  de  la  Soc.  Philomathique,  1818-19,  p.  148. 


648 


CIRCULATION. 


der,  and  tail.  There  is,  however,  considerable 
variety  in  regard  to  the  distribution  of  the 
posterior  abdominal  veins  in  fishes;  and  com- 
parative anatomists  do  not  appear  as  yet  to 
have  connected  these  varieties  with  any  general 
view  of  their  uses.  In  the  Gadus  the  venous 
blood  from  the  tail  and  middle  of  the  ab- 
domen goes  to  the  kidneys  only  by  venae  ad- 
vehentes.  In.  the  Silurus  the  blood  of  the 
posterior  parts  of  the  body  is  carried  to  both 
the  kidneys  and  liver ;  and  in  the  carp,  pike, 
and  perch,  to  the  kidneys,  liver,  and  vena 
cava  at  once.  The  blood  from  the  testicle, 
ovary,  swimming  bladder,  and  kidneys,  most 
frequently  goes  to  the  vena  cava.* 

Course  of  the  blood  in  Invertebrate  Animals. 
— In  investigating  the  course  of  the  blood  in 
animals  destitute  of  a  vertebral  column  and 
cerebro-spinal  nervous  system,  we  are  no  longer 
guided  by  any  such  analogies  of  form,  posi- 
tion, and  use,  as  those  just  attempted  to  be 
traced  in  the  circulatory  organs  of  the  Ver- 
tebrata  ;  for  each  class  of  Invertebrate  animals, 
as  Mollusca,  Articulata,  and  Zoophyta,  and 
even  their  subordinate  orders,  differ  so  widely 
from  one  another  in  their  organization,  that 
we  are  at  a  loss  to  discover  any  general  plan 
or  type  to  which  their  circulatory  organs  may 
be  referred. 

In  all  of  the  Invertebrate  animals  in  which 
there  is  a  regular  progressive  motion  of  the 
nutritive  fluids,  there  exists  also  a  central  con- 
tractile organ  to  which  the  name  of  heart  is 
applied,  from  its  functional  rather  than  struc- 
tural analogy  to  the  central  propelling  organ 
of  the  circulation  in  Vertebrate  animals;  and 
in  many  of  them,  the  outgoing  and  returning 
vessels  in  which  the  circulation  is  performed 
may  be  distinguished  into  arteries  and  veins, 
by  a  difference  of  structure  as  well  as  of  office. 
From  the  same  kind  of  analogy,  the  name  of 
auricle  is  given  to  the  weaker  part  of  the  heart 
of  Invertebrate  animals,  which  serves  to  re- 
ceive the  returning  blood  from  the  veins,  when 
such  a  cavity  exists,  and  we  call  ventricle  the 
stronger  and  more  muscular  part  which  propels 
the  blood  into  the  arteries.  The  general  form 
of  these  parts,  however,  and  their  position 
relatively  to  the  other  systems,  render  it  ex- 
tremely difficult,  if  not  altogether  impossible, 
to  trace  any  strict  anatomical  correspondence 
between  the  heart  and  bloodvessels  of  Verte- 
brate and  Invertebrate  animals.  In  the  Inver- 
tebrate animals,  the  heart  and  principal  artery 
are  generally  placed  on  the  upper  part  of  the 
body,  above  the  alimentary  canal  and  largest 
portions  of  the  nervous  system ;  while  in  all 
Vertebrate  animals  the  order  is  reversed,  the 
brain  and  spinal  marrow  being  above,  the 
heart  below  the  alimentary  canal. 

In  the  Invertebrata,  as  in  the  higher  animals, 
the  respiratory  change  of  the  blood  is  the  most 
important  function  to  which  its  course  or  cir- 
culation bears  a  constant  relation.  In  the 
Vertebrata  the  blood  flows  from  the  heart  to 

*  See  the  papers  of  Jacobson  and  Nicolai  al- 
ready referred  to,  and  the  extended  Researches  of 
Rathke,  Meckel's  Archiv,  1826,  and  Aunal.  des 
Sciences  Nat.  torn.  ix. 


the  respiratory  organ,  while  in  the  Invertebrata 
the  blood  very  generally  arrives  at  the  heart 
after  having  passed  through  the  respiratory 
organ,  and  is  propelled  from  the  heart  into  the 
systemic  circulation  :  the  vessels,  therefore,  in 
which  respiration  is  effected  in  the  lower  ani- 
mals may  be  considered  as  belonging  in  ge- 
neral to  the  venous  circulation  only,  while  in 
the  higher  classes  of  animals,  arteries  alone, 
or  arteries  and  veins  together,  conduct  the 
blood  through  the  respiratory  organ.  Another 
remarkable  difference  between  the  circulation 
of  the  nutritive  fluids  in  Vertebrated  animals 
and  that  in  the  Invertebrate  classes  consists  in 
this,  that  in  the  first  the  digested  food  or  chyle 
and  the  lymph  are  taken  up  by  a  system  of 
vessels  distinct  from  those  circulating  blood, 
and  are  poured  into  the  venous  circulation 
at  one  or  more  determinate  places ;  while  in 
the  latter  animals,  the  bloodvessels,  so  far  at 
least  as  we  yet  know,  perform  the  office  of 
lacteal  and  lymphatic  absorbent  vessels  as  well 
as  of  circulatory  organs.  In  the  Invertebrate 
animals  also,  there  is  no  vena  portae,  as  in  the 
Vertebrata,  and  the  liver  is  supplied  with  blood 
only  by  a  hepatic  artery. 

In  investigating  the  structure  of  the  circu- 
latory organs  in  different  classes  of  Inverte- 
brate animals,  we  at  once  perceive  that  no 
accurate  correspondence  can  be  traced  between 
the  varieties  of  their  forms  and  the  places 
assigned  to  the  animals  in  a  Zoological  arrange- 
ment ;  for  we  find  among  the  Mollusca  some 
tribes  having  a  highly  developed  and  compli- 
cated circulatory  apparatus,  and  others  with 
heart  and  bloodvessels  comparatively  simply 
organized.  The  same  discrepancy  occurs 
among  the  Crustacea,  Annelida,  and  Insects ; 
and  among  the  Entozoa  and  some  other  tribes 
of  Zoophytes,  while  some  possess  a  simple 
circulatory  apparatus,  in  others  we  are  not  able 
to  discover  any  vestige  of  a  vascular  system. 

There  is  a  considerable  number  of  the  lower 
animals  in  which  no  vascular  system  has  yet 
been  discovered,  and  in  which  the  nutritious 
juices  are  supposed  to  pass  from  the  alimentary 
cavity  by  interstitial  transudation  through  all  the 
parts  of  their  bodies.  The  circulation  has,  how- 
ever, been  recently  shewn  to  exist  in  animals 
formerly  believed  to  be  without  it,  and  the 
farther  progress  of  Comparative  Anatomy  may 
diminish  still  more  the  number  of  animals 
believed  to  be  destitute  of  circulating  organs : 
in  the  present  state  of  our  knowledge,  it  is 
therefore  as  difficult  to  say  with  certainty  in 
what  animals  this  function  is  deficient,  as  it  is 
to  fix  in  which  it  is  of  the  most  simple  or  most 
complicated  kind. 

Mollusca. — The  greater  number  of  the  Mol- 
lusca live  in  water  and  breathe  by  means  of 
gills,  but  many  aquatic  Mollusca,  possessing 
a  branchial  apparatus,  appear  to  have  their 
blood  aerated  in  other  parts  of  the  body  also. 
There  is  a  strong  muscular  heart  in  all  the  ani- 
mals belonging  to  this  class,  which  when  single 
is  always  systemic,  (figs.  320, 321,  and  322,  Jf.) 
In  the  Cephalopoda,  besides  the  aortic  or  sys- 
temic heart,  which  has  only  one  cavity  or 
ventricle,  each  vessel  (fig.  320,  B)  leading  to 


CIRCULATION. 


649 


Fig.  320. 


Cuttle-fish. 

the  gills  has  a  dilated  contractile  portion  (B*), 
which  dilatations  may  be  considered  as  bran- 
chial hearts,  so  that  there  are  three  separate 
contractile  portions  of  the  circulatory  system. 
In  the  Gasteropoda  and  Pteropoda,  there  is 
only  one  heart.  This  organ  is  strong  and  mus- 
cular, provided  with  valves,  and  consisting  of 
an  auricular  and  a  ventricular  cavity  (figs.  321 
and  322,  A,  H).  In  the  Testaceous  Acephala, 
the  heart  is  nearly  of  the  same  structure  as  in 
the  orders  just  mentioned,  but  less  fully  deve- 
loped. In  most  of  them,  as  also  in  the  Gas- 
teropodous  Mollusca,  the  rectum  passes  through 
the  ventricle.  The  auricle  is  occasionally 
double.  The  Brachiopoda  have  two  aortic 
hearts,  but  of  a  very  simple  structure,  not 
being  divided  into  auricular  and  ventricular 
portions.  The  naked  Acephala,  such  as  the 
Ascidiae,  have  the  simplest  heart  of  all  the 
Mollusca,  consisting  of  a  thin  membranous 
ventricle  apparently  without  valves. 

In  all  these  animals,  the  course  of  the  blood 
is  generally  considered  to  be  the  following: 
Arterial  blood  only  passes  through  the  systemic 
or  aortic  heart  (or  hearts  where  this  organ  is 
double),  and  is  carried  to  the  system  by  the 
branches  of  the  systemic  arteries  (A,  a).  The 

VOL.  I. 


altered  blood,  returning  in  the  veins  of  the 
system,  is  collected  into  one  or  more  trunks 
(  F),  and  carried  in  the  subdivided  branches 
of  these  (Jig.  321,  Jig.  322,  B)  to  the  re- 

Fig.  321. 


Helix. 

spiratory  organ,  which  consists  of  branchial 
plates  or  fringes  in  the  greater  number,  but  in 
some  of  the  Gasteropoda,  as  in  the  Garden- 
Snail,  of  pulmonary  sacs.  In  most  cases,  the 
whole  of  the  blood  returning  from  the  system 
passes  through  the  respiratory  organ.  In 
others,  especially  in  some  Bivalves,  the  vena 
cava  or  systemic  veins  send  branches  directly 
to  the  auricle  as  well  as  to  the  gills. 

In  the  compound  Ascidiae,  Mr.  Lister*  has 
recently  discovered  one  of  the  most  remarkable 
modifications  of  the  circulation  with  which  we 

*  Philos.  Trans.  1834,  p.  378. 
2  u 


650 


CIRCULATION. 


are  acquainted.  Mr.  Lister  finds  that  the  dif- 
ferent Ascidise  of  a  branched  animal  are  not  only 
connected  together  by  the  polypiferous  stem, 
but  have  a  common  circulation.  In  each  indi- 
vidual there  is  a  heart  consisting  of  one  cavity 
only,  and  pulsating  about  thirty  or  forty  times 
in  a  minute.  In  the  common  stem,  the  mo- 
tion of  the  globules  of  the  blood  indicates 
distinctly  two  currents  running  in  opposite 
directions.  One  of  the  currents  enters  the 
Ascidia  by  its  peduncle  and  proceeds  directly 
to  the  heart ;  the  blood  issuing  from  the  heart 
is  propelled  into  the  gills  as  well  as  the  system 
at  once,  and  upon  its  return  from  thence  the 
returning  current  proceeds  out  of  the  animal 
by  its  peduncle  again  into  the  common  stem, 
whence  it  goes  to  circulate  through  another  of 
the  ascidiae  attached  to  the  stem.  The  direc- 
tions of  the  currents  appeared  to  be  reversed 
every  two  minutes  or  less.  According  to  Mr. 
Lister,  when  one  of  the  ascidiee  is  separated 
from  the  common  stem,  its  circulation  goes  on 
in  an  independent  manner;  the  blood  return- 
ing from  the  body  being  conducted  into  the 
heart,  but  the  alternation  of  the  directions  still 
continues, — a  circumstance  which  points  out  an 
important  difference  between  the  compound 
and  the  simple  ascidiae,  in  which  last  the  cir- 
culating fluid  is  generally  believed  to  pass  from 
the  gills  into'  the  heart,  and  to  hold  continually 
the  same  direction. 

Articulata.  —  In  this  class  of  animals, 
varied  as  the  forms  of  the  circulatory  organs 
appear,  the  position  of  their  principal  parts  is 
much  more  constant  than  in  the  Molluscous 
animals.  In  some,  as  the  Decapodous  Crus- 
tacea, there  is  a  short  and  thick  muscular  heart 
connected  with  the  systemic  arteries.  In 
others,  the  contractile  part  of  the  vascular 
system  is  much  more  like  a  dilated  artery  than 
a  circumscribed  heart,  as  occurs  in  some  other 
Crustacea,  spiders,  and  insects;  and  in  the 
Annelida  the  greater  part  of  the  large  vessels 
seem  to  be  endowed  with  a  contractile  power 
by  which  they  propel  the  blood. 

Annelida. — Although  the  Annelida  form  the 
highest  division  of  the  class  Articulata  in  the 
arrangement  of  Cuvier,  their  circulatory  organs 
may  for  the  most  part  be  regarded  as  more 
simple  than  those  of  most  of  the  others.  The 
circulation  is  best  known  in  the  J^aides,  the 
Leech,  Earthworm,  and  Sand  worm.  In  all  of 
these,  the  blood,  which  is  generally  red,  moves 
gradually  forwards  in  the  vessels  situated  on 
the  upper  surface  of  the  animal,  and  backwards 
in  the  vessels  placed  below  or  on  the  abdomi- 
nal side.  There  are  also  numerous  cross  vessels 
which  transmit  the  blood  from  one  side  to 
another,  or  from  above  downwards,  or  from  be- 
low upwards,  in  each  of  the  compartments  or 
joints  of  the  animal.  The  upper  vessels,  being 
generally  the  most  contractile,  are  considered 
as  the  arteries ;  the  lower  vessels  as  veins.* 

The  organs  of  circulation  appear  to  be  sim- 
plest in  the  Naides.  In  these  animals,  the 
contractile  part  or  heart  is  represented  by  an 
artery  above.  This  vessel  turns  round  at  the 

*  See  the  article  Annelida,  p.  169. 


head  into  the  vein  which  is  below.  The  artery 
sends  its  blood  partly  into  the  gills,  placed 
along  the  whole  length  of  the  body,  from  which 
it  again  receives  the  returning  blood,  and  by 
numerous  lateral  branches,  which  may  be  re- 
garded as  the  only  capillary  vessels,  it  sends 
blood  across  the  body  of  the  animal  into  the 
vein.  The  motion  of  the  blood  appears  to  be 
partly  progressive  and  partly  oscillatory. 

Lumbricus.  —  In   the  common   earthworm, 

there  are  two  principal  vessels,  the  one  (Jig. 

323,  a,)  placed  above  and  the  other  (v)  below, 

and  extending  the 

Fig.  323.  whole    length    of 

the  body ;  these 
two  principal  ves- 
sels communicate 
together  by  very 
numerous  small 
cross  branches  (c), 
and,  in  the  neigh- 
bourhood of  the 
ovaries,  by  from 
five  to  eight  very 
remarkable  neck- 
lace-shaped or 
moniliform  ves- 
sels (h,  H).  At 
the  place  of  junc- 
tion of  these  mo- 
niliform vessels 
with  the  lower 
longitudinal  one, 
there  are  small  di- 
latations of  that 
vessel,  which  are 
believed  to  aid  in 
propelling  the 
blood  by  their  con- 
tractions. There 
are  also  three  other 
longitudinal  ves- 
sels, much  smaller 
than  the  principal 
or  median  ones, 
which  join  with 
Lumbricus.  the  cross  anas- 

tomosing     twigs. 

The  upper  principal  vessel  pulsates  in  an  un- 
dulatory  manner,  the  contraction  taking  place 
first  at  the  posterior  part,  and  proceeding  gra- 
dually forwards.  In  these  animals,  however, 
the  course  of  the  blood  does  not  appear  to  be 
very  well  known.  It  is  believed  to  be  from 
behind  forwards  in  the  upper  vessel  and  from 
before  backwards  in  the  lower,  but  there  must 
be  also  lateral  motion.  Both  the  upper  and 
lower  vessels  are  said  to  give  off  pulmonary 
branches. 

Arenicola. — In  the  sandworms  also,  besides 
the  principal  upper  and  lower  vessels,  there  are 
two  smaller  ones,  placed  one  on  each  side  of  the 
abdominal  nervous  cord,  and  two  others  upon  the 
intestine;  between  these  there  is  a  very  minute 
net-work  of  smaller  branches.  The  branchial 
arteries  are  derived  from  the  upper  longitudinal 
vessel,  the  branchial  veins  lead  into  the  lower. 
The  greater  part  of  the  blood  proceeds  from  the 
upper  vessel  into  the  gills  by  the  branchial  arte- 


CIRCULATION. 


ries ;  by  the  branchial  veins  it  gains  the  lower 
vessel.  This  vessel  may  be  regarded  as  the 
systemic  artery,  and  sends  the  arterial  blood, 
by  the  numerous  anastomosing  branches,  up- 
wards across  the  intestine,  and  through  the 
other  parts  into  the  upper  vessel.  The  upper 
vessel  communicates  also  with  the  lower  ante- 
riorly by  the  lateral  dilatations  named  auricles, 
which  are  supposed  to  furnish  some  blood  to 
the  upper  vessel.  A  part  of  the  blood  at  the 
anterior  extremity  of  the  lower  vessel  is  said  to 
be  propelled  into  the  two  subordinate  vessels 
placed  along  the  sides  of  the  nervous  cord. 
In  this  course  which  the  blood  is  stated  to 
follow,  it  does  not  appear  to  be  known  whether 
its  motion  is  of  a  regular  progressive  kind  or 
only  undulatory. 

Leech. — In  the  leech  the  principal  and  most 
highly  contractile  longitudinal  vessels  are  placed 
one  on  each  side  (Jig.  324,  a,  a),  and  there  are 
also  two  lesser  longitu- 
Fig.  324.  dinal  vessels,  one  supe- 

rior and  the  other  inferior 
(a*),  all  which  commu- 
nicate freely  together  by 
small  cross  branches  along 
the  whole  body  (c).  It 
is  remarkable  that  the  lower 
median  vessel  (a*)  incloses 
the  ganglionic  nervous 
cord,  so  as  to  bathe  it  with 
blood.  Both  pulmonary 
arteries  and  veins  are 
branches  of  the  lateral  ves- 
sels ;  a  capillary  network 
between  them  distributing 
the  blood  minutely  over 
the  pulmonary  sacs  or 
vesicles.  The  pulmonary 
veins  form  very  remarkable 
dilated  and  coiled  por- 
tions, which  seem  to  be 
endowed  with  a  high  de- 
gree of  contractility.  Ac- 
cording to  J.  Miiller,  for 
a  certain  number  of  pul- 
sations, the  middle  and  the 
lateral  vessel  of  one  side 
contract  together,  and  pro- 
pel the  blood  into  the 
lateral  vessel  on  the  other 
side,  and  then  the  order 
is  reversed,  and  the  middle 
vessel  acts  along  with 
the  lateral  vessel  of  the 
other  side,  so  that  one  lateral  vessel  is  always 
dilated  while  the  median  and  opposite  lateral 
ones  are  contracted,  and  vice  versa.  According 
to  some  there  is  thus  only  an  alternate  motion 
of  the  blood  from  one  side  to  the  other,  while 
others  believe  that  there  is  at  the  same  time  a 
gradual  progressive  motion  of  the  blood  for- 
wards in  the  upper  vessel  and  backwards  in 
the  lower  one.* 

The  course  of  the  blood   in  the   principal 

*  See  a  full  account  of  most  of  the  opinions  of 
observers  on  this  subject,  as  well  as  original  obser- 
vations by  Rudolf  Wagner,  in  the  Isis  for  1832, 
p.  643. 


Erpobdella  or  Leech. 


parts  of  the  circulatory  organs  is  nearly  the 
same  in  the  rest  of  the  Articulata,  viz.  Crustacea, 
Arachnida,  and  Insects,  as  in  Annelida.  In  all 
of  them  the  central  propelling  organ,  whether  in 
the  form  of  a  heart  or  consisting  only  of  a  dilated 
arterial  vessel,  such  as  the  dorsal  vessel  of  in- 
sects, is  situated  on  the  upper  surface  of  the 
animal,  above  the  alimentary  canal,  while  the 
returning  vessels  are  situated  on  the  lower  sur- 
face of  the  body,  on  each  side  of  the  nervous 
ganglionic  cord.  The  respiratory  circulation, 
when  occurring  in  a  distinct  set  of  vessels, 
forms  a  part  of  the  venous  system,  and  the 
heart,  which  has  no  auricle,  is  systemic  or 
aortic. 

Insects. — All  perfect  Insects,  whether  inha- 
bitants of  air  or  water,  breathe  air  alone.  In 
these  animals  there  is  not  a  separate  and  dis- 
tinct respiratory  organ  in  one  part  of  the  body 
only,  but  the  atmospheric  air  is  carried  by 
minute  elastic  and  tough  tubes  ramified  to  an 
infinite  degree  of  minuteness  into  every  part  of 
their  body. 

The  dorsal  vessel  of  insects  forms  a  long  and 
wide  contractile  artery,  larger  in  general  behind 
than  before,  in  which  the  contractions  begin  at 
the  posterior  extremity,  and  proceed  gradually 
forwards  with  an  undulatory  motion.  In  the 
greater  number  of  perfect  insects,  we  are  not 
acquainted  with  any  other  vessels  or  passages 
in  the  body,  through  which  the  blood  moves, 
and  this  fluid  seems  in  these  insects  to  oscillate 
backwards  and  forwards  in  the  dorsal  vessel 
alone.  This  state  of  the  circulation  in  insects, 
according  to  the  ingenious  views  of  Cuvier,  is 
related  to  the  distribution  of  the  respiratory 
organ  over  the  whole  body,  in  consequence  of 
which  the  air  is  brought  in  contact  with  the 
more  perfect  blood  contained  in  the  dorsal 
vessel,  and  the  nutritious  fluids  supposed  to 
pervade  interstitially  the  rest  of  the  body.  The 
recent  discovery  by  Carus  of  a  continuous  cir- 
culation of  the  blood  through  arteries  and  veins 
in  a  few  of  the  perfect  insects,  and  more  espe- 
cially in  some  larvae,  must  modify  the  above 
views,  which,  ingenious  as  they  must  appear  to 
all,  do  not  account  so  satisfactorily  for  the  ab- 
sence of  a  systemic  as  for  the  want  of  a  pulmo- 
nary circulation.  The  circulation  of  the  blood 
of  Insects  may  be  most  easily  seen  in  the 
aquatic  larvae  of  Neuropterous  Insects,  as  the 
Agrion,  Ephemera,  Semblis,  and  Libellula,*  in 
which  it  was  first  discovered. 

In  these  larvae  it  may  be  described  generally 
as  follows.  The  dorsal  vessel  (/g.325,  H)  is 
connected  anteriorly  and  posteriorly  by  several 
branches  with  the  inferior  or  returning  vessels 
(v,  v\  which,  running  along  the  whole  body, 
receive  the  blood  from  the  anterior  extremity, 
and  carry  it  into  the  posterior  extremity  of  the 
dorsal  vessel.  The  antennae  and  first  joint  of 
the  legs,  as  well  as  the  fin-shaped  caudal  pro- 
cesses, receive  each  a  loop  of  vessel  from  the 
abdominal  current;  and  from  the  motion  of  the 
globules  in  these  transparent  parts,  the  circula- 
tion can  be  more  easily  seen  in  them  than  in 

*  We  have  ourselves  seen  the  circulation  in  the 
larvae  of  two  Neuropterous  Insects. 

2  u  2 


652 


CIRCULATION. 


Fig.  325. 


Insects. 


any  other  parts  (Jig.  325  **,  «,  v).  A  net- 
work of  vessels  is  also  distributed  over  the 
surface  of  the  imperfectly  formed  wings.  As 
the  metamorphosis  from  the  larval  to  the 
perfect  state  advances,  and  shortly  after  the 
insect  leaves  the  water  to  assume  the  aerial 
condition,  the  circulation  of  the  blood  be- 
comes gradually  confined  to  a  more  and 
more  circumscribed  space.  The  loops  extend- 
ing into  the  wings,  limbs,  caudal  processes, 
and  antennae,  become  shorter;  when  the  meta- 
morphosis is  complete,  they  become  entirely 
closed,  and  in  general  this  change  is  followed 
by  the  disappearance  of  the  inferior  lateral  or 
returning  currents  also.  These  remarkable 
changes  in  the  circulatory  organs  at  once  indi- 
cate an  interesting  relation  of  their  condition  to 
the  changes  in  the  mode  of  life  of  the  insect. 
In  the  aquatic  state,  the  caudal  and  lateral 
laminae,  antennae,  and  wings  may  be  considered 
as  serving  the  purposes  of  gills,  for  the  blood 
is  carried  to  them,  and  exposed  upon  their 
surfaces  to  the  action  of  the  water.  The  larvae 
of  the  neuropterous  insects  generally  feed 
largely,  but  their  life  during  the  perfect  condi- 
tion, when  the  circulation  has  ceased,  is  of 
short  duration,  and  they  either  take  very  little 
food,  or  live  in  absolute  abstinence.  It  has 
been  also  shewn  that  the  dorsal  vessel  consists  of 
different  compartments,  between  each  of  which 
a  valvular  apparatus  (fig.  325*,  .r)  prevents  the 
passage  of  the  blood  in  a  retrograde  direction. 
There  are  lateral  openings  in  the  neighbourhood 
of  the  valves,  by  which  it  would  appear  that 


the  blood  is  admitted  into  the  dorsal  vessel  from 
cross  branches  (Jig.  325**,  y)  passing  directly 
from  the  lateral  streams.  It  may  be  mentioned 
that  the  larger  returning  streams  of  blood,  situ- 
ated on  the  lower  side  of  the  body,  are  said  by 
Carus  and  Wagner,  we  cannot  judge  with  what 
reason,  not  to  be  inclosed  within  vascular  pa- 
rietes,  but  to  run  loose  in  the  texture  of  the 
insect.  A  complete  circulation  is  not,  how- 
ever, confined  to  the  larvae  of  insects,  having 
been  discovered  by  Carus  and  others  in  some 
of  the  perfect  insects.  Carus  saw  it  in  the 
wings  of  the  Semblis  developed  for  flight.  The 
circulation  has  also  been  seen  by  Carus  in  the 
larvae  of  Water-beetles,  Hydrophilus,  and  Dy- 
tiscus,  and  by  Ehrenberg  and  Hemprich  in  the 
Mantis,  so  that  the  circulation  has  now  been 
discovered  in  insects  belonging  to  four  orders, 
viz.  Coleoptera,  Diptera,  Orthoptera,  and  Neu- 
roptera. 

Crustacea. — In  the  Stomapoda,  Isopoda,  and 
Branchiopoda,  or  in  the  Squill,  Oniscus,  and 
Monoculus  or  Daphnia,  the  circulation  is  ge- 
nerally described  as  being  of  the  same  simple 
kind  as  that  just  stated  to  occur  in  the  larva  of 
insects,  with  this  exception,  that  the  blood  is 
carried  to  gills  for  the  purpose  of  undergoing 
a  respiratory  change.  In  most  of  them  the 
venous  blood  which  is  sent  to  the  gills  comes 
directly  from  the  systemic  veins.  From  the 
description  given  by  Gruithuisen  of  the  circu- 
lation in  the  Daphnia,*  it  would  appear,  if  his 
observations  are  correct,  that  the  venous  blood 
is  sent  to  the  heart  before  going  to  the  gills, — 
a  distribution  very  dissimilar  from  that  which 
exists  in  the  rest  of  the  articula'.ed  animals.  In 
this  animal,  Gruithuisen  also  describes  an  au- 
ricle and  ventricle  in  the  heart. 

The  investigations  of  Messrs.  Audouin  and 
Milne  Edwards  have  pointed  out  very  clearly 
the  structure  of  the  circulatory  organs  and  the 
course  of  the  blood  in  the  larger  Decapodous 
and  some  other  Crustacea.  The  aortic  heart 
(Jig.  326,  H),  consisting  of  a  single  ventricular 
cavity,  and  situated  below  the  posterior  margin 
of  the  thoracic  shield,  gives  off  six  systemic 
arteries  (A,  fl),  which  convey  the  arterial  blood 
to  the  various  organs  of  the  body  and  to  the 
liver  (/*).  The  venous  blood,  returning  thence 
in  the  systemic  veins  (v,  v),  is  collected  on  the 
lower  surface  of  the  body  into  sinuses  (  V,  V), 
from  which  the  branchial  arteries  (B)  take  their 
origin  ;  the  branchial  veins  (6)  return  the  blood 
which  has  passed  through  the  gills  to  the  heart. 
Arachnida. — In  those  of  the  Arachnida  in 
which  the  respiratory  organ  consists  of  tracheae 
like  that  of  insects,  the  circulation  has  been 
supposed  to  be  much  the  same  as  in  these 
latter  animals.  The  dorsal  vessel,  however, 
approaches  to  the  form  of  a  heart  posteriorly, 
being  there  more  dilated  at  one  part  than  in 
the  rest  of  its  course,  and  considerable  lateral 
vessels  are  known  to  be  given  off  from  it  upon 
either  side.  In  others  of  the  spiders,  in  which 
the  respiratory  organ  consists  of  pulmonary  ca- 
vities admitting  air,  it  is  conjectured  that  the 
blood  is  distributed  on  the  surface  of  the  plates 

*  Nova  Acta  Nat.  Cur.  xiv.  p.  404. 


CIRCULATION. 


653 


Fig.  326. 


Lobster. 

within  these  sacs,  as  upon  the  gills  or  lungs  of 
other  animals,  but  the  exact  course  of  the  blood 
does  not  appear  as  yet  to  have  been  satisfacto- 
rily ascertained  in  these  animals.  Audouin* 
believes  it  to  be  essentially  the  same  as  in  the 
Crustacea.  The  long-shaped  dorsal  vessel  or 
heart  gives  off  arteries  to  both  sides,  and  re- 
ceives at  one  place  branches  from  the  gills. 
The  veins  form  only  spaces  or  sinuses,  and  not 
vessels  on  the  abdominal  side  of  the  animal. 
The  blood  propelled  from  the  artery  is  passed 
through  the  system,  returning  from  which,  it  is 
collected  into  the  venous  sinuses  below,  thence 
it  proceeds  to  the  pulmonary  organs,  and  after 
passing  through  them,  returns  to  the  heart. 

Zoophytes.  —  The  general  character  of  the 
circulation  in  this  class  is  exceedingly  ob- 
scure ;  for  while  in  some  of  the  animals  be- 
longing to  it,  comparative  anatomists  have  not 
succeeded  as  yet  in  pointing  out  any  distinct 
vascular  system  ;  in  others,  they  have  been  at  a 
loss  to  determine,  among  various  vascular  or- 
gans, which  of  them  forms  the  proper  circula- 
tory system  corresponding  with  that  of  higher 
animals. 

Echinodermata. — Among  the  Zoophytes  the 


Echinodermata  present  the  most  fully  deve- 
loped vascular  system  with  which  we  are  ac- 
quainted. According  to  the  observations  of 
Tiedemann  and  Delle  Chiaje,  who  have  inves- 
tigated the  structure  of  these  animals  with  great 
success,  there  are  two  principal  divisions  of  the 
vascular  system,  described  by  the  first  of  the 
above-mentioned  authors  as  distinct  from  one 
another,  by  the  other  as  communicating  toge- 
ther. 

We  do  not  feel  inclined  to  consider,  in  ac- 
cordance with  the  view  of  these  authors,  that 
series  of  cavities  which  is  employed  in  loco- 
motion as  a  part  of  the  nutritive  circulatory 
organs. 

That  part  of  the  vascular  system  of  these 
animals  again,  which  is  situated  in  the  neigh- 
bourhood of  the  alimentary  canal,  very  proba- 
bly corresponds  with  the  circulatory  organs 
which  we  have  been  describing  in  other  ani- 
mals; since  arteries  and  veins  can  be  distin- 
guished in  it,  and  there  is  good  reason  to  be- 
lieve that  a  circulation  of  fluid  takes  place 
through  its  vessels  in  all  the  kinds  of  Echino- 
dermatous  animals. 

In  the  Holothuria,  the  principal  artery  or 
heart  is  connected  with  a  ring  situated  round 
the  commencement  of  the  alimentary  canal, 
from  which  the  systemic  arteries  are  given  off: 
the  systemic  veins  send  branches  to  the  gills, 
and  the  returning  vessels  from  these  organs 
transmit  the  circulating  fluid  through  one  large 
trunk  into  the  heart. 

The  intestinal  vascular  system  of  the  Asterias 
and  Echinus  is  somewhat  similar  to  that  of  the 
Holothuria,  consisting  of  annular  vessels,  from 
which  arteries  and  veins  are  given  off,  and  con- 
nected with  a  dilated  contractile  canal,  consi- 
dered as  a  heart. 

Planaria. — Next  to  the  Echinodermata  in 
respect  of  the  degree  of  perfection  of  their  cir- 
culatory organs,  may  be  mentioned  the  Plana- 
riae,   in  which   M.  Uuges*  has  pointed  out  a 
very  remarkable  system  of  vessels  which  ap- 
pear to  constitute  circulatory  organs   (fg.  327, 
a,  a  ).     For  some  time  previously  to  the  disco- 
very of  these  vessels,  the  sin- 
Fig.  327.        gularly  branched  intestinal  ca- 
vity of  the  Planaria  and  some 
Entozoa  was  believed  to  hold 
the  place  of  organs  of  circula- 
tion, the  same  cavity  in  which 
digestion  occurs  being  believed 
to  carry  by  its  ramifications  the 
nutritious    fluids    to    different 
parts  of  the  body.     But  Duges 
has  shewn  the  existence  in  them 
of  a  system  of  vascular  organs 
resembling   considerably   those 
of  the  Leech,  to  which  animals 
the  Planaria  bears,  in  other  parts 
of  its  organization  also,  astriking 
analogy.    The  vascular  system 
Planaria.        of  the  Planaria  consists  of  three 
principal    longitudinal    trunks, 
two  lateral  and  one  dorsal  or  median,  which  are 
all  united  together  by  numerous  minute  anasto- 


Sce  the  article  Arachnida,  p.  206. 


*  Annal.  dcs  Sciences  Natur.  xv,  p.  160. 


654 


CIRCULATION. 


mosing  vessels.  The  larger  parts  of  the  longi- 
tudinal vessels  have  been  observed  to  contract 
and  dilate;  but  neither  a  regular  progressive 
circulation,  nor  a  connection  of  the  vascular 
with  any  distinct  respiratory  system  has  as  yet 
been  detected. 

Entozoa. — In  the  Entozoa,  organs  of  circu- 
lation somewhat  similar  to  those  just  mentioned 
in  the  Planarise  have  been  found  by  Bojanus 
and  Mehlis  in  the  Distoma  and  Tristoma, 
and  by  Nordmann*  in  those  remarkable  small 
Entozoa  inhabiting  the  aqueous  chamber  of 
the  eyes  of  some  quadrupeds,  the  Diplosto- 
mum,  and  in  the  Diplozoon.  In  the  first  of 
these  animals,  the  motion  of  fluid  in  the  vas- 
cular system  is  exceedingly  obscure;  but  in 
the  Diplozoon  (Jig.  328),  Nordmann  saw,  with 

Fig.  328. 


DiploKOon. 

a  high  magnifying  power,  currents  moving  in 
opposite  directions  in  two  sets  of  vessels  (a,  v) 
placed  on  each  side  of  both  limbs  of  the  ani- 
mal. These  vessels,  termed  external  and  in- 
ternal, are  said  to  terminate  posteriorly  in  a 
dilated  bag,  to  which  Nordmann  gives  the 
name  of  receptacle  of  the  chyle.  The  organs 
of  circulation  of  the  Diplozoon  differ,  there- 
fore, in  this  respect  from  those  of  the  Plaparia, 
to  which  otherwise  they  bear  considerable  si- 
milarity; for,  in  the  latter  animal,  the  vascular 
system  appears  to  be  entirely  closed.  Accord- 
ing to  Nordmann  and  Ehrenberg  no  contrac- 
tions or  dilatations  of  the  vessels  are  visible. 

Acalepha. — In  some  of  the  Medusa  tribe, 
or  Acalephae,  there  appears  to  be  no  distinct 
circulatory  apparatus;  and  we  observe  that  in 
these  instances,  the  alimentary  cavity  is  of 
great  extent  and  is  often  much  ramified  on  the 
surface  of  the  animal. 

In  others  there  are  distinct  vessels  with  a 

*  Micographische  Beitrage,  p.  69.    Berlin,  1832. 


circulation  of  fluid  within  them.  The  distri- 
bution of  this  very  simple  kind  of  vascular 
system  was  first  discovered  by  Eschscholtz,  who 
has  described  its  form  particularly  in  the  Cesium 
and  Beroe.  In  the  latter  animal,  it  is  stated 
that  eight  arterial  vessels  and  two  veins  unite 
with  a  large  annular  vessel  which  surrounds  the 
mouth,  and,  according  to  Eschscholtz's*  conjec- 
ture, another  vascular  ring,  situated  at  the  pos- 
terior extremity  of  the  body,  forms  the  means 
of  communication  between  the  arteries  and 
veins  in  that  region.  Branches  pass  from  the 
external  or  arterial  vessels,  and  from  the  in- 
ternal or  venous  vessels  to  the  fins,  which 
organs  seem  to  serve  at  once  for  respiration 
and  for  locomotion.  Although  the  motion  of  a 
yellowish  fluid  containing  globules  has  been 
seen  in  these  vessels,  the  complete  circulation 
does  not  appear  to  have  been  made  out  in 
a  satisfactory  manner. 

Infusoria.  —  Some  kind  of  circulation  is 
stated  to  have  been  observed  by  Ehrenberg  in 
some  of  the  Infusoria ;  but  this  is  an  observa- 
tion which,  with  every  confidence  in  the  ac- 
curacy of  this  celebrated  microscopic  observer, 
we  feel  inclined  to  consider  as  liable  to  fallacy, 
on  account  of  the  prevalence  of  various  kinds 
of  ciliary  currents  in  the  interior  of  many  of 
these  animals. 

Polypi. — We  would  extend  the  same  remark 
to  the  last  kind  of  circulation  to  which  we 
shall  allude,  viz.  those  singular  currents  of 
fluid,  which  were  discovered  by  Cavolini  and 
recently  observed  by  Mr.  Lister  in  some  of 
the  Polypiferous  Zoophytes.  According  to 
the  latter  observer,  in  each  of  the  divisions 
of  the  stem  of  the  Tubularia  indivisa,  a  cur- 
rent of  fluid  carrying  globules  along  with  it 
is  seen  proceeding  up  one  side  and  down  the 
other.  In  various  Sertulariae,  the  direction  of 
the  current  becomes  reversed  from  time  to 
time.  Similar  phenomena  are  to  be  observed 
in  Campanularise  and  Plumularise.  The 
striking  analogy  which  these  currents  bear  to 
those  occurring  in  the  stems  of  some  plants,  as 
Chara  and  Caulinia,  seem  to  us  to  bring  them 
under  another  class  of  phenomena  than  those 
of  the  vascular  circulation  of  the  higher  ani- 
mals. We  do  not,  however,  intend  to  enter 
upon  the  consideration  of  this  subject,  as  it 
is  already  fully  treated  of  under  the  article 
CILIA. 

In  concluding  our  notice  of  the  simpler 
forms  of  the  circulatory  organs,  we  would  re- 
mark that  one  of  the  great  difficulties  which 
retards  the  acquisition  of  an  accurate  know^ 
ledge  of  the  function  of  circulation  in  the 
lowest  classes  of  animals,  proceeds  from  our 
inability  to  determine,  whether  currents  moving 
within  enclosed  spaces  in  these  animals  belong 
to  the  circulation  of  their  blood  and  nutritious 
fluids,  or  are  connected  with  respiration,  loco- 
motion, and  other  processes  of  their  economy ; 
and  this  is  an  obstacle  to  the  progress  of  the 
investigation  which  from  its  nature  we  cannot 
hope  soon  to  see  removed. 

*  System  der  Acalephen.  Berlin,  1829.  See 
the  article  Acalepho-,  p.  43- 


CIRCULATION. 


655 


In  the  Planaria,  Medusa,  some  Entozoa, 
and  Polypi,  the  subdivided  or  ramified  coeca 
of  the  alimentary  cavity  (jig  328,  I)  must 
obviously  contribute  to  the  effect  of  furnishing 
a  supply  of  digested  matter  to  the  different 
regions  of  the  body,  and  of  thus  rendering  a 
distinct  vascular  system  in  them  to  a  certain 
extent  unnecessary.  But  in  these  simpler 
kinds  of  animals,  and  even  in  those  of  them 
in  which  distinct  vessels  have  been  discovered, 
we  cannot  regard  such  scattered  tubes  as  the 
only  principal  means  of  distributing  the  nutri*- 
tious  fluids  to  the  different  parts  of  the  body. 
They  may  assist  in  bringing  this  about ;  but  it 
is  also  necessary  to  suppose  the  occurrence  of 
an  interstitial  movement  or  organic  transuda- 
tion  of  the  fluids,  in  order  to  furnish  to  all 
the  parts  the  materials  for  assimilation. 

III.  PHENOMENA  OF  THE  CIRCULATION  AND 

POWERS    MOVING    THE    BLOOD. 

In  proceeding  to  the  third  division  of  our 
subject,  viz.  the  phenomena  of  the  circulation 
and  the  powers  by  which  the  blood  is  moved,  we 
would  remark,  that,  however  desirable  it  might 
appear  in  a  systematic  work  of  this  kind  to  treat 
of  these  two  subjects  under  distinct  heads,  such 
a  separation  would  have  the  effect  of  detaching 
inconveniently  the  facts  from  the  legitimate 
conclusions  which  may  be  drawn  from  them. 
We  shall  first  state  the  phenomena  and  causes 
of  the  motion  of  the  blood  which  belong  strictly 
to  the  organs  of  circulation  themselves,  and 
afterwards  shall  treat  of  various  circumstances 
connected  with  the  other  functions  by  which 
the  circulation  is  modified.  In  this  view  it  is 
our  chief  object  that  the  facts  adduced  should 
bear  upon  the  explanation  of  the  motion  of  the 
blood  in  the  human  body,  but  from  the  nature 
of  the  investigation  the  facts  themselves  must 
be  drawn  chiefly  from  experiments  made  upon 
the  lower  animals.  Of  course  those  experi- 
ments and  observations  which  have  been  made 
on  Mammiferous  animals  have  most  value  in 
relation  to  such  a  view  of  the  function  as  that 
which  it  is  our  intention  to  give.  The  order 
which  we  shall  follow  is  founded  on  the  course 
which  the  blood  pursues.  We  shall  treat,  1, 
of  the  passage  of  the  blood  through  the  heart; 
2,  of  its  flow  in  the  arteries ;  3,  of  its  passage 
from  the  arteries  to  the  veins  through  the  ca- 
pillaries; and  4,  of  its  flow  in  the  veins. 

1.  Flow  of  the  blood  through  the  heart. — 
That  the  muscular  contraction  of  the  heart  is, 
in  man  and  in  all  animals  in  which  this  organ 
exists,  the  principal  source  of  the  power  by 
which  the  blood  is  propelled  in  its  course, 
seems  to  be  satisfactorily  proved  by  the  facts, 
that  whenever  the  action  of  the  heart  ceases  or 
is  impeded,  the  whole  circulation  ceases,  and 
that,  when  an  obstruction  prevents  the  action 
of  the  heart  from  reaching  the  blood  in  any  of 
the  bloodvessels,  the  flow  of  blood  ceases  almost 
instantaneously  in  all  the  branches  proceeding 
from  the  obstructed  vessel.  The  constant  and 
regular  persistence  of  the  contractions  of  this 
muscular  ors;an  from  the  commencement  of  life 
to  its  termination,  the  early  period  at  which  it 
begins  to  act  in  the  foetus,  viz.  before  any  re- 


gular circulation  of  blood  takes  place,  and  the 
existence  of  a  heart  or  some  similar  contractile 
organ  in  all  those  animals  in  which  a  regular 
circulation  of  blood  or  nutritious  fluids  occurs, 
are  confirmatory  of  the  view  suggested  by  direct 
observation  and  experiment.  Under  the  article 
HEART  will  be  found  a  detailed  account  of  the 
structure  and  functions  of  this  organ ;  in  this 
place  we  shall  only  state,  in  as  few  words  as 
we  can,  what  seems  to  have  been  best  ascer- 
tained regarding  its  action,  in  so  far  as  this 
appears  to  have  a  reference  to  the  force  of  im- 
pulsion and  direction  which  it  communicates 
to  the  blood. 

The  action  of  the  heart  may  be  observed  by 
opening  the  chest  of  a  living  animal,  or  for  a 
short  time  in  one  immediately  after  death,  or 
best  of  all  in  an  animal  deprived  of  sense  and 
motion  by  poison,  and  in  which  artificial  respira- 
tion is  maintained ;  it  has  also  been  seen  in  chil- 
dren born  with  ectopia  cordis,  or  in  persons  in 
whom  from  accident  a  part  of  the  heart  has 
been  exposed  to  view.  When  observed  under 
one  or  other  of  these  circumstances,  the  action 
or  contraction  of  the  whole  heart  is  seen  to 
consist  of  two  motions,  viz.  1,  the  contraction 
or  systole  of  the  auricular  part,  and  2,  that  of 
the  ventricular  part  of  the  organ.  The  con- 
traction of  the  auricle  immediately  precedes 
that  of  the  ventricle  and  seems  to  be  continued 
into  it,  and  the  systole  of  each  cavity  is  imme- 
diately followed  by  its  diastole  or  relaxation.* 
After  the  relaxation  of  the  ventricle,  there  is  a 
period  of  repose,  or  a  pause  in  the  action  of 
the  heart,  during  which  motion  seems  to  be 
nearly  suspended.  At  the  moment  when  the 
systole  of  the  ventricle  takes  place,  the  heart 
appears  to  be  diminished  in  all  its  dimensions, 
and  exactly  at  the  same  instant  of  time,  the 
apex  is  seen  to  be  moved  towards  the  sternum, 
in  whatever  position  the  animal  is  placed. 
This  tilting  forwards  of  the  apex  gives  the 
heart  a  pulsation  against  the  ribs  that  can  be 
felt  externally.  This  pulsation  probably  de- 
pends on  the  arrangement  of  the  muscular 
fibres  of  the  heart,  as  the  raising  of  the  apex 
occurs  when  the  heart  is  removed  from  the 
body  and  is  empty  of  blood.  At  the  time 
of  the  systole  the  heart  is  thicker  and  more 
conical  in  its  figure  than  during  the  diastole; 
when  held  in  the  hand  it  feels  hard,  and  the 
ventricles  appear  to  have  propelled  the  whole 
of  the  blood  out  of  their  interior,  as  far  as  one 
can  judge  from  the  great  diminution  in  their 
size.  In  the  inferior  animals,  as  Reptiles  and 
Fishes,  its  colour  is  lighter  from  the  expulsion 
of  the  blood.  During  the  relaxation  or  dias- 
tole, the  heart  appears  to  fall  away  from  the 


*  In  some  of  the  lower  animals,  in  the  foetus 
of  the  Bird  at  an  early  period,  and  in  warm- 
blooded animals  when  the  action  of  the  heart  is 
weakened,  as  at  the  approach  of  death,  the  con- 
traction is  seen  to  begin  in  the  venous  sinus  of 
the  auricle,  extend  through  it  to  the  ventricle,  and 
from  one  part  of  the  ventricle  to  another  in  a  gra- 
dual manner.  In  the  Batrachia,  the  contraction 
begins  in  the  veins,  and  after  passing  through  the 
auricle  and  ventricle,  extends  into  the  commence- 
ment of  the  aorta. 


656 


CIRCULATION. 


chest,  its  parietes  become  flaccid,  and  it  as- 
sumes a  flattened  form.  The  pulse  in  the 
arteries,  which  is  in  truth  nothing  more  than 
the  communication  of  the  impulse  of  the  heart 
along  the  blood  in  these  vessels,  corresponds, 
at  least  in  the  larger  arteries  near  the  heart,  very 
exactly  in  time  with  the  ventricular  systole  and 
the  beat  on  the  walls  of  the  chest.  The  action 
of  the  heart  is  accompanied  by  two  sounds, 
that  can  be  heard  on  applying  the  ear  to  the 
cardiac  region.  The  first  of  these  sounds  is 
synchronous  with  the  systole  of  the  ventricles, 
the  second  with  their  diastole;  the  second 
follows  the  first  immediately,  and  is  succeeded 
by  an  interval  of  silence.  Of  the  space  of 
time  in  which  a  full  action  of  the  heart  is 
completed,  the  systole  of  the  ventricle  occu- 
pies nearly  a  third,  the  systole  of  the  auricle 
less  than  a  quarter ;  the  dilatation  of  the  ven- 
tricle and  repose  taken  together  must  be 
effected  in  the  remainder. 

The  heart,  from  its  structure  and  action,  may 
justly  be  considered  as  a  living  or  self-moving 
double  forcing-pump,  which  is  continually 
filled  at  one  part  and  emptied  at  another. 
During  one-third  of  the  time  of  a  complete 
action  of  the  heart,  the  blood  in  the  arteries  is 
impelled  onwards  by  the  direct  impulse  of  the 
ventricles  at  their  systole.  During  the  other 
two-thirds  of  the  time,  while  the  ventricle  is 
inactive,  the  communication  between  its  cavity 
and  the  great  arteries  is  stopped  by  the  closure 
of  the  semilunar  valves,  and  the  blood  must, 
therefore,  at  this  time  be  propelled  by  the 
elastic  and  other  forces  of  the  arteries  them- 
selves. But  the  heart  continues  to  receive 
blood  from  the  veins  during  a  longer  time  than 
it  gives  out  any  of  that  fluid,  for  the  auricles 
offer  a  resistance  to  the  entrance  of  blood  du- 
ring only  a  space  of  less  than  a  quarter  of  the 
time  employed  in  a  complete  action  of  the 
heart,  and  the  blood  is  continually  impelled 
into  the  auricles  as  well  as  the  ventricles  du- 
ring the  whole  time  that  these  cavities  are  not 
contracted,  although  more  blood  enters  the 
auricles  immediately  after  their  relaxation,  and 
more  is  propelled  into  the  ventricles  just  be- 
fore their  contraction  than  in  the  rest  of  the 
time. 

During  the  systole  of  the  ventricles,  while  the 
stream  of  blood  issues  from  their  cavities  into 
the  first  adjoining  parts  of  the  large  arteries, 
the  folds  of  the  semilunar  valves  are  laid  close 
to  the  inner  side  of  these  vessels.  As  soon  as 
the  contractile  force  of  the  ventricles  ceases, 
the  free  edges  of  the  semilunar  valves  are 
brought  towards  the  middle  of  the  vessel,  and 
applied  firmly  against  one  another  so  as  to 
close  the  ventriculo-arterial  orifices  :  this  is 
effected  by  the  pressure  of  the  column  of 
blood  acted  upon  by  the  elastic  coats  of  the 
arteries,  assisted  perhaps  by  the  elasticity  of 
the  borders  of  the  valves  themselves  and  by 
the  change  of  position  consequent  on  dilatation 
of  the  ventricles. 

During  the  systole  of  the  ventricles,  the 
auriculo-ventricular  or  tricusjiid  and  mitral 
valves  are  closed,  so  as  to  prevent  in  a  great 
measure  regurgitation  of  the  blood  from  the 


ventricles  into  the  auricles.  When  the  ven- 
tricles are  in  the  relaxed  state,  the  valves 
are  opened  by  the  stream  of  blood  flowing 
from  the  auricles.  The  circumstance  that 
the  free  margins  of  the  mitral  and  tricuspid 
valves  are  bound  down  to  the  inner  walls 
of  the  ventricles  by  the  tendinous  cords  at- 
tached to  the  fleshy  pillars,  and  that,  by  the 
contraction  of  these  pillars,  the  free  margins 
of  the  valves  mnst  be  pulled  further  down 
into  the  ventricle  than  in  the  relaxed  state, 
has  occasioned  to  some  a  difficulty  in  under- 
standing their  action,  and  led  them  to  suppose 
that  the  columns  carneae  must  necessarily  be 
relaxed  at  the  time  of  the  ventricular  systole, 
and  that  by  contracting  while  the  ventricle  is 
in  its  diastole,  the  fleshy  pillars  contribute  to 
open  the  valves.  The  direct  observation  of 
the  contraction  of  the  columnar  carneae  in  the 
heart  of  an  animal  taken  from  the  body,  and 
an  attentive  observation  of  the  structure  of 
these  valves,  from  which  it  appears  that  the 
tendinous  cords  passing  to  opposite  flaps  of 
the  valves  frequently  come  from  the  same 
columnae  carneae  or  point  of  attachment  in  the 
ventricular  paries,  sufficiently  prove  that  these 
fleshy  pillars  actually  contract  at  the  same  mo- 
ment as  the  rest  of  the  parietes  of  the  ven- 
tricles, and  that  their  contraction,  besides 
drawing  the  free  margins  of  the  valves  down- 
wards into  the  ventricles,  must  also  tend  to 
make  them  approach  one  another  more  nearly ; 
and  we  are  therefore  entitled  to  form  the  con- 
clusion, that,  while  the  tendons  serve  to  fix 
the  valves,  the  action  of  the  columnae  carneae  is 
to  draw  these  down  so  as  to  allow  the  blood 
to  pass  behind  them,  and  to  press  them  to- 
gether and  close  them  in  the  same  manner  as 
the  semilunar  valves  of  the  aorta  and  pulmo- 
nary artery  are  shut. 

The  apparently  greater  facility  of  the"  en- 
trance of  blood  into  the  heart  at  one  time  than 
at  another,  has  given  rise  to  the  opinion  enter- 
tained by  some  physiologists  that  the  dilatation 
of  the  heart  is,  like  the  contraction,  accom- 
panied with  the  production  of  a  new  force, 
which  draws  the  blood  from  the  veins  towards 
the  heart.  Some  who  regard  muscular  elon- 
gation as  a  source  of  new  power  have  gone  so 
far  as  to  suppose  that  this  force  is  even  greater 
than  that  accompanying  contraction,  but  it  is 
manifest  that  such  a  view  is  opposed  by  every 
thing  we  know  of  muscular  action,  which  leads 
to  the  belief  that  the  shortening  of  muscular 
fibre  ought  alone  to  be  considered  as  an  active, 
and  the  subsequent  elongation  as  entirely  a 
passive  change.  Others  suppose  the  ventricles 
of  the  heart  to  dilate  in  consequence  of  elas- 
ticity, in  the  same  manner  as  a  bag  of  caout- 
chouc does  after  being  compressed  with  some 
degree  of  force.  Attempts  have  even  been 
made  to  measure  the  extent  of  the  force  pro- 
duced during  the  dilatation  of  the  ventricles, 
by  endeavouring  to  ascertain  the  weight  which 
is  displaced  by  this  motion  of  the  heart.  We 
would  not  wish  to  be  understood  to  deny  the 
possibility  of  the  heart's  exerting  some  slight 
force  in  this  way  during  its  dilatation,  but  it 
appears  very  clear  that  a  measurement  of  the 


CIRCULATION. 


657 


kind  referred  to  must  be  so  difficult  as  to  be 
almost  useless;  indeed,  it  is  very  probable 
that  some  have  mistaken  the  contraction  for 
the  dilatation,  and  we  shall  afterwards  find 
that  the  power  of  suction,  exerted  by  the  heart 
on  the  blood,  as  measured  by  the  force  with 
which  the  veins  are  emptied,  is  veiy  small 
indeed.  It  is  clear  that  the  blood  driven  on 
from  behind  by  a  propelling  power,  or  flowing 
through  parts  which  are  pressed  upon  by 
neighbouring  organs,  must  enter  the  heart 
more  easily  during  the  relaxation  of  the  pa- 
rietes  of  the  ventricle  than  at  any  other  period 
during  the  heart's  action,  so  as  to  give  rise 
to  an  appearance  of  suction,  but  direct  expe- 
riments make  it  sufficiently  obvious  that  the 
force  of  impulsion  from  behind  is  almost  the 
sole  cause  of  the  entrance  of  the  blood  from 
the  trunks  of  the  great  veins  into  the  cavities 
of  the  heart. 

In  order  to  form  an  estimate  of  the  time  in 
which  a  given  quantity  of  blood  may  pass 
through  the  heart,  or  of  the  time  in  which  the 
whole  quantity  of  blood  contained  in  the  body 
would  take  to  pass  through  the  heart,  several 
data  are  required  which  are  not  yet  furnished 
by  accurate  experiments.  In  the  first  place, 
we  must  know  the  average  quantity  of  blood 
contained  in  the  body,  and,  in  the  next  place, 
the  quantity  which  is  evacuated  from  the  heart 
at  each  stroke  or  systole  of  the  ventricles. 

With  regard  to  the  first  of  these  points, 
a  number  of  calculations  have  been  made 
which  vary  greatly  in  their  results.  Animals 
have  been  bled  to  death  by  the  section  of  the 
larger  bloodvessels,  and  the  quantity  of  blood 
lost  has  been  measured.  The  quantity  of 
blood  lost  in  this  way  seems  to  have  varied 
from  l-10th  to  l-30th  of  the  weight  of  the 
whole  body,  and  Dr.  Moulins,  who  formed 
his  estimates  from  experiments  of  this  kind, 
rated  the  quantity  of  blood  in  the  human  body 
at  eight  or  nine  Ibs.  only,  or  l-20th  of  the 
weight  of  an  average  sized  man,  taken  at  150 
or  160  Ibs.  But  it  is  obvious  that  when  one  of 
the  larger  bloodvessels  is  opened,  from  the 
suddenness  of  the  flow,  the  animal  faints  or 
dies  before  the  whole  or  even  a  considerable 
proportion  of  the  blood  has  been  lost;  and  it 
has  been  ascertained  from  numerous  obser- 
vations, that  when  the  blood  flows  more  gra- 
dually and  from  small  vessels,  as  occurs  in 
hemorrhages  from  the  nose,  stomach,  rectum, 
or  uterus,  a  proportionally  much  greater  quan- 
tity of  blood  may  be  lost  than  occasions  death 
in  animals  experimented  upon  by  the  section 
of  the  larger  arteries  or  veins.  Instances  are 
on  record  in  which  from  ten  to  twenty  Ibs. 
and  even  greater  quantities  of  blood  have 
flowed  from  the  human  body  within  twenty- 
four  hours.*  We  feel  inclined  on  these 
grounds  to  coincide  with  the  estimate  formed 
by  Haller,  that  the  blood  forms  about  a  fifth  of 
the  weight  of  the  body,  or  equals  from  twenty- 
five  to  thirty  Ibs.  in  a  man  of  the  average 
weight  of  150  Ibs.  It  is  obvious  that  this 


*  Sec  Haller'.s  Eleincma,   and  Kiill  on  the  An. 
Econ. 


must  vary  in  different  individuals  from  other 
circumstances  besides  a  difference  of  stature. 
In  the  young,  the  quantity  of  blood  is  con- 
sidered to  be  greatest.  Of  the  whole  of  the 
blood  contained  in  the  body,  it  is  estimated  by 
Haller,  and  probably  with  accuracy,  that  four 
parts  are  contained  in  the  arterial  and  nine  in 
the  venous  system. 

In  endeavouring  to  estimate  the  quantity 
of  blood  which  passes  through  the  heart  in  a 
given  time,  we  must  find  the  capacity  of  the 
cavities  of  the  heart,  we  must  ascertain  whe- 
ther the  cavities  on  the  two  sides  are  of  the  same 
size,  and,  as  it  is  almost  impossible  to  measure 
the  quantity  of  blood  evacuated  from  the  heart 
at  each  stroke,  we  must  find  to  what  e\tent 
the  ventricles  empty  themselves  during  their 
systole.  It  is  obvious  that,  so  long  as  the 
circulation  is  uniform  and  no  local  accumu- 
lation of  blood  takes  place,  the  same  quantity 
of  blood  must  pass  out  of  the  ventricles  into 
the  larger  arteries  which  enters  by  the  veins, 
and  for  the  same  reasons,  that  the  quantity  of 
blood  passing  through  the  right  and  left  cavi- 
ties of  the  heart  must  be  exactly  equal.  The 
circumstance  that  an  equal  quantity  of  blood 
passes  out  of  the  right  and  left  cavities  of  the 
heart  during  their  systole  does  not  entitle  us 
to  conclude  that  the  capacity  of  the  different 
auricles  and  ventricles  is  the  same,  because 
any  one  of  them  during  its  systole  may  be 
more  or  less  completely  emptied  than  the  rest, 
and  a  regurgitation  obviously  takes  place  from 
some  of  them,  so  that  the  whole  blood  which 
they  contain  is  not  propelled  in  its  onward 
course.  According  to  some  anatomists  the  au- 
ricles are  larger  in  capacity  than  the  ventricles, 
probably  in  the  proportion  of  three  or  two  and 
a  half  to  two,  and  the  auricles  are  by  no  means 
completely  emptied  during  their  systole.  An 
opinion  has  very  generally  prevailed  that  the 
cavities  on  the  right  side  of  the  heart  are  some- 
what larger  than  those  on  the  left.  There  is  no 
doubt  that  in  making  measurements  of  the  rela- 
tive capacity  of  the  two  sides  after  death,  it  is 
most  frequently  found  so ;  but  it  is  obvious  that 
some  have  very  much  overrated  the  difference, 
and  there  is  much  reason  to  believe  that  the 
greater  capacity  of  the  right  auricle  and  ven- 
tricle depends  in  part  on  the  accumulation  of 
blood  which  generally  takes  place  in  most 
kinds  of  slow  death  in  the  pulmonary  arteries, 
and  in  part  also  upon  the  greater  thinness  and 
consequent  distensibility  of  the  right  ventricle. 
In  men  dying  suddenly,  and  in  animals  killed 
purposely,  in  which  the  pulmonary  artery  is 
opened  so  as  to  allow  of  the  free  egress  of  the 
blood  from  the  right  side  of  the  heart,  the 
capacity  of  this  ventricle  is  not  greater  than 
that  of  the  left,  and  the  proportions  of  the 
capacity  of  the  two  sides  of  the  heart  usually 
found  after  slow  death  are  sometimes  reversed 
when  a  ligature  is  placed  on  the  aorta  and  the 
pulmonary  artery  is  opened.*  Most  authors 
seem  to  have  agreed  to  follow  the  estimate  of 
the  capacity  of  the  ventricles  given  by  Hales 
in  his  Medical  Statics.  This  author  esti- 

*  Sabatier. 


658 


CIRCULATION. 


mates  the  capacity  of  the  left  ventricle  at 
1$  oz.  fluid  measure,  and  that  of  the  right  at 
2  oz.  The  contemplation  of  the  muscular 
structure  of  the  left  ventricle,  and  the  great 
diminution  in  size  it  undergoes  during  its  sys- 
tole, would  induce  us  to  conclude  that  it  must 
be  completely  emptied  during  the  contraction, 
and  that  there  cannot  remain  any  blood  even 
among  the  columnse  carnese.  The  right  ven- 
tricle does  not  appear  from  the  quantity  of  its 
muscular  substance  to  be  so  well  suited  to  be 
emptied,  but  its  position  round  the  left  must 
assist  considerably  in  the  diminution  of  its 
size  during  its  systole.  In  some  cases  of  sud- 
den death  in  healthy  persons,  both  ventricles 
have  been  found  completely  empty. 

The  whole  of  the  blood  issuing  from  the 
ventricles  into  the  first  parts  of  the  great  arte- 
ries is  retained  within  these  arteries  by  the 
action  of  the  semilunar  valves,  and  it  would 
appear  that  in  the  healthy  condition  the  adap- 
tation of  these  valves  is  such  that  very  little 
if  any  blood  regurgitates  or  flows  backwards 
into  the  ventricles.  At  the  time  that  the  auri- 
cles contract,  a  very  different  phenomenon 
presents  itself,  for  while  a  certain  quantity  of 
the  blood  from  the  auricles  passes  onwards 
into  the  ventricles,  some  is  driven  back  into  the 
orifices  of  the  great  veins.  This  venous  re- 
gurgitation  is  particularly  evident  in  the  veins 
connected  with  the  right  side  of  the  heart,  the 
orifices  of  which  have  no  valves  or  very  im- 
perfect ones ;  and  it  gives  rise  to  a  pulsation  in 
their  larger  branches,  synchronous  with  the 
systole  of  the  auricle,  as  may  be  seen  in  most 
thin  persons  in  the  jugular  vein  at  the  lower 
part  of  the  neck.  It  would  appear  that  upon 
some  occasions,  even  in  the  state  of  health, 
a  certain  back  stroke  from  the  ventricles  also 
is  perceptible  in  the  veins,  and  Hales  was  of 
opinion  that  some  of  the  blood  (half  an  ounce) 
from  the  right  ventricle  flowed  back  into  the 
auricle  during  each  systole  of  the  ventricle. 
It  must  be  apparent  that  immediately  after  the 
auricle  has  ceased  to  propel  its  contents  into 
the  ventricle,  and  just  when  the  systole  of  the 
ventricle  begins,  the  column  of  blood  extend- 
ing from  the  ventricle  into  the  auricle  through 
the  auriculo-ventricular  orifice  must  be  con- 
tinuous, and  the  pressure  of  the  ventricular 
systole  must  thus  be  transmitted  upwards  until 
the  valves  flap  together  and  close  that  opening. 
Accordingly,  in  some  persons  in  health,  a  ve- 
nous pulse,  synchronous  with  the  ventricular 
systole,  is  occasionally  seen  or  felt  in  the  jugu- 
lar veins,  but  this  appearance  is  much  more 
commonly  a  sign  of  disease;  for  the  venous 
pulse  which  is  synchronous  with  the  ventri- 
cular systole  is  much  increased  when  an  ob- 
stacle presents  itself  to  the  free  flow  of  blood 
through  the  pulmonary  artery,  or  when  from 
ossification  or  other  morbid  alteration,  the  auri- 
culo-ventricular valves  do  not  close  accurately 
the  passage  in  which  they  are  placed. 

We  may  conclude,  from  the  observations 
above  alluded  to,  that  on  an  average  each  of  the 
ventricles  of  the  heart  gives  out  nearly  one  ounce 
and  a  half  at  each  stroke;  and  we  may  now 
state  the  general  calculation  of  the  time  that 


the  blood  takes  to  move  through  the  heart, 
which  is  generally  founded  upon  the  above 
data.  Let  us  suppose  the  heart  to  beat  seventy- 
five  times  in  a  minute,  which  is  nearly  the  ave- 
rage number  of  pulsations  in  a  healthy  man  in 
the  prime  of  life,  and  assume  the  quantity  of 
blood  in  the  body  at  28  Ibs. ;  and  let  us  sup- 
pose that  \\  oz.  of  blood  is  expelled  from  each 
ventricle  into  the  great  arteries  connected  with 
them,  then  112  oz.  or  7  Ibs.  of  blood  would 
pass  through  each  ventricle  in  a  minute,  and 
28  Ibs.  in  four  minutes ;  or  in  three  minutes, 
if  the  quantity  of  blood  passing  through  the 
ventricles  at  each  systole  be  estimated  at  two 
ounces,  i.  e.  a  quantity  of  blood  equal  to  that 
which  we  conceive  to  be  contained  in  the 
whole  body,  would  flow  through  the  heart  in 
the  short  space  of  four  minutes,  and  this  quan- 
tity would  run  the  same  course  fifteen  times  in 
an  hour.  We  must  guard  against  conceiving, 
on  the  one  hand,  that  this  calculation  affords 
any  accurate  measure  of  the  quantity  of  blood 
which  actually  passes  through  the  ventricles  in 
a  given  time,  for  there  are  innumerable  circum- 
stances which  tend  to  cause  this  quantity  to 
vary  to  a  considerable  extent ;  and  on  the  other 
hand,  it  must  at  all  times  be  borne  in  mind 
that  we  can,  from  such  calculations,  estimate 
only  the  velocity  of  the  blood  in  the  heart  itself, 
or  the  time  which  a  certain  quantity  of  blood 
takes  to  pass  through  its  cavities,, but  that  we 
are  not  furnished  with  any  measure  of  the  time 
that  the  whole  of  the  circulating  quantity  of 
blood  actually  takes  to  pass  through  its  course, 
for  the  length  of  the  courses  through  which  the 
blood  has  to  pass  in  different  parts  of  the  vas- 
cular system  varies  to  such  a  degree,  that  in 
some  places,  as  for  example  in  the  bloodves- 
sels of  the  heart  itself,  the  return  to  the  heart 
must  be  effected  in  less  than  half  the  time 
employed  by  that  which  is  transmitted  to  the 
extremities.  On  comparing  the  longest  or 
shortest  calculations  of  this  kind  made  by  dif- 
ferent authors,  we  shall  find  that  the  time  of  a 
circulation  is  made  to  vary  from  six  minutes 
and  a  half  to  one  minute. 

We  shall  not  at  present  enter  upon  the  con- 
sideration of  the  force  with  which  the  blood 
issues  from  the  left  ventricle  of  the  heart,  as 
the  experiments  by  which  this  force  is  deter- 
mined being  made  upon  the  arteries,  come 
more  suitably  to  be  treated  of  under  the  arte- 
rial circulation. 

2.  Phenomena  of  the  arterial  circulation. — 
In  proceeding  to  consider  the  phenomena  and 
causes  of  the  flow  of  blood  through  the  arterial 
system,  we  purpose  to  treat  of,  1st,  the  velocity; 
2d,  the  force  of  the  blood  in  the  arteries ;  3d, 
the  nature  of  the  arterial  pulse ;  4th,  the  vital 
properties  of  the  arteries;  and  5th,  the  influence 
exerted  by  this  class  of  bloodvessels  on  the  cir- 
culation. We  shall  find  that,  in  this  part  of 
our  subject,  the  difficulty  of  becoming  ac- 
quainted with  the  immense  variety  of  circum- 
stances capable  of  modifying  the  flow  of  the 
blood,  has  prevented  the  explanation  of  pheno- 
mena which  are  in  themselves  sufficiently  sim- 
ple and  apparent.  In  our  remarks  upon  the 
above-mentioned  topics,  we  shall  endeavour  to 


CIRCULATION. 


659 


refer  the  phenomena  of  the  circulation,  as  far 
as  we  can,  to  hydraulic  principles,  which,  when 
correctly  applied,  must  form  the  only  sure 
guide  in  conducting  a  physiological  inquiry  of 
this  nature. 

The  flow  of  the  blood,  as  it  is  expelled  from 
the  left  ventricle,  may  be  said  to  be  intermit- 
tent, for  it  moves  only  at  the  time  of  the  ventri- 
cular systole.  Farther  on  in  its  course,  in  the 
larger  as  well  as  the  middle  sized  arteries,  the 
flow  of  blood  is  remittent,  or  is  more  rapid 
after  each  beat  of  the  heart,  and  by  the  time  it 
arrives  at  the  capillary  vessels  and  commence- 
ment of  the  veins,  the  velocity  is  rendered  per- 
fectly uniform.  The  effect,  therefore,  produced 
by  the  arterial  tubes  is  to  convert  an  intermittent, 
first  into  a  remittent,  and  afterwards  into  a  uni- 
form force.  When  an  opening  is  made  into 
one  of  the  larger  arteries,  the  jet  of  blood  which 
issues  is  regularly  increased  in  velocity  at  every 
systole  of  the  ventricle.  In  the  very  small  ar- 
teries, this  acceleration  of  the  stream  becomes 
less  perceptible.  We  know  that  it  has  altoge- 
ther disappeared  in  the  smallest  vessels  or  ca- 
pillaries, from  microscopic  observation  of  the 
flow  of  the  blood  in  them,  and  the  uniformity 
of  the  velocity  of  the  stream  in  the  veins  is 
clearly  shewn  in  all  instances  in  which  a  vein 
is  opened,  as  in  the  common  operation  of 
bleeding  from  the  arm. 

Various  circumstances  shew  that  in  the  living 
body  the  blood  forms  an  uninterrupted  column 
of  fluid  in  the  bloodvessels,  and  that  the  whole 
vascular  system  is  kept  in  a  state  of  forced  dis- 
tension by  the  reiterated  impulses  communi- 
cated to  the  blood  by  the  ventricular  contrac- 
tions. Besides  the  general  fulness  of  the  blood- 
vessels and  their  connection  with  the  heart,  we 
may  mention  as  proofs  of  the  distended  state  of 
the  vascular  system,  the  facts,  1st,  that,  on 
opening  any  of  the  bloodvessels,  the  blood 
issues  with  greater  force  at  the  first  moment 
than  afterwards ;  and  2d,  that  when  we  imitate 
the  propulsion  of  the  blood  through  the  arteries 
and  veins  by  artificial  injection  of  fluids  in  a 
dead  animal,  we  observe  that  the  jet  from  an 
opened  vessel  continues  to  flow  for  some  time 
after  we  have  ceased  to  drive  the  piston  of  the 
syringe.  The  arteries  being  much  stronger 
than  the  veins,  re-act  with  greater  power  than 
they  do  against  the  distending  force  of  the 
heart.  Were  the  arteries  rigid  tubes,  it  is  ma- 
nifest that  in  a  given  time  just  as  much  blood 
would  pass  from  their  remote  extremities  into 
the  commencement  of  the  veins,  as  enters  them 
by  the  mouth  of  the  aorta;  but  the  arteries 
must  be  fuller  at  one  time  than  another,  for  the 
quantity  of  blood  expelled  from  the  ventricle  at 
each  systole,  must  pass  suddenly  into  the  first 
part  of  the  aorta,  while  an  equal  quantity  of 
blood,  which  must  necessarily  pass  from  the 
remote  arteries  into  veins,  as  it  moves  uni- 
formly, must  employ  the  whole  period  of 
time  occupied  by  a  complete  action  of  the 
heart  in  its  passage ;  and  consequently  it  is 
manifest,  that  the  arterial  system  must  be  fuller 
just  after  than  immediately  before  the  contrac- 
tion of  the  ventricle.  The  arteries  are  distensi- 
ble and  elastic,  they  yield  a  little  to  every  sua- 


ble ai 


ce-ssive  stroke  of  the  ventricle,  and  during  the 
diastole  they  re-act  by  their  elasticity,  so  as  to 
keep  up  the  flow  of  blood.  We  have  already 
said,  in  speaking  of  the  heart,  that  the  muscular 
contraction  of  that  organ  is  the  chief,  if  not  the 
only  source  of  the  power  propelling  the  blood. 
It  is  only  in  those  arteries  which  are  nearest  to 
the  heart,  however,  that  the  blood  can  be  said  to 
be  propelled  by  the  direct  impulse  of  the  ven- 
tricle, for  in  the  rest  of  the  arterial  system,  the 
progression  of  the  blood  is  immediately  effected 
by  the  elastic  power  of  the  arteries,  called  into 
operation  in  consequence  of  their  distension  by 
the  action  of  the  heart.  In  the  experiments  of 
artificial  injection  of  the  bloodvessels  in  dead 
animals  already  mentioned,  as  long  as  we  con- 
tinue to  drive  the  piston  of  the  syringe,  and  to 
propel  fluids  through  the  arteries  into  the  veins, 
the  arteries  are  kept  in  a  state  of  forced  disten- 
sion ;  in  consequence  of  this,  the  fluid  issues 
from  an  opened  artery  with  a  jet  accelerated 
after  each  successive  stroke  of  the  piston,  and 
continues  to  flow  for  some  time  after  the  pro- 
pelling power  has  ceased  to  act.  The  unifor- 
mity of  the  stream  of  fluid  from  the  veins, 
which  occurs  in  the  same  experiment,  is  a  proof 
that  the  continued  flow  of  blood  in  these  tubes 
may,  in  the  living  body,  be  owing  to  an  impul- 
sion from  the  heart,  transmitted  by  the  arteries, 
and  that  it  is  caused  by  the  elasticity  of  the 
coats  of  the  vessels  themselves. 

a.  Velocity  of  the  blood  in  different  arteries. 
The  space  of  the  aorta  filled  up  by  the  blood 
propelled  from  the  ventricle  at  each  systole, 
divided  by  the  time  occupied  in  its  propul- 
sion, constitutes  the  velocity  of  the  blood  in 
the  first  part  of  the  aorta.  The  diameter  of  the 
aperture  of  the  aorta  at  the  ventricle  being  taken 
as  on  an  average  1*12  of  an  inch,*  its  area  would 
be  one  square  inch,  and  consequently  1%  02. 
which  equal  2*45  cubic  inches  of  blood,  would 
occupy  a  little  more  than  2-5  inches  of  the  aorta, 
supposing  its  size  to  be  for  such  an  extent  of  a 
uniform  diameter.  As  it  is  satisfactorily  ascer- 
tained by  actual  measurement,  that  the  blood 
contained  in  the  smaller  vessels  is  in  much 
greater  quantity  than  that  in  the  larger  trunks ; 
or,  in  other  words,  as  the  capacity  of  the  smaller 
vessels  taken  together  is  greater  than  that  of 
the  larger,  it  will  at  once  be  apparent,  that  the 
velocity  of  the  blood  must  diminish  in  passing 
from  the  larger  to  the  smaller  vessels.  The 
arterial  and  venous  vessels  may  in  fact  be  re- 
garded as  two  hollow  cones,  curved  so  as  to  be 
joined  at  their  apices  to  the  heart,  and  at  their 
bases  to  one  another.  The  veins,  being  more 
numerous  and  wider  than  the  arteries,  must  be 
represented  by  a  wider  cone.  The  section  of 
these  cones  at  any  place  is  supposed  to  give 
the  combined  area  of  the  section  of  the  vessels 
at  a  corresponding  distance  from  the  heart. 

The  estimates  made  by  different  authors  of 
the  relative  velocity  of  the  blood  in  the  larger 
and  smaller  vessels,  differ  in  a  great  degree, 

*  The  aperture  of  the  aorta  is  somewhat  less 
than  one  inch  in  diameter  in  most  persons ;  we 
may,  however,  adopt  the  above  estimate  of  its  size, 
as  the  sinus  of  the  aorta  is  much  wider  than  its 
aperture. 


660 


CIRCULATION. 


and  are  exceedingly  unsatisfactory.  Haller, 
who  fully  admitted  the  greater  capacity  of  the 
smaller  arteries,  and  allowed  that  the  flow  of 
the  blood  must  therefore,  from  hydraulic  prin- 
ciples, become  less  rapid  in  passing  from  the 
trunks  to  their  branches, — a  proposition  which 
he  illustrates  by  comparing  the  stream  of  blood 
in  its  passage  to  a  river  which  enters  a  lake, — 
was  yet  inclined,  from  the  result  of  his  actual 
observations,  to  deny  that  the  velocity  is  much 
less  in  the  smaller  than  in  the  larger  arteries. 
Spallanzani,  although  admitting  more  explicitly 
still  than  Haller  the  necessity  of  such  a  retarda- 
tion, seems  to  have  met  with  the  same  difficulty 
in  reconciling  theory  with  his  attempts  to  mea- 
sure the  velocity  of  the  blood  in  the  small  ves- 
sels :  and  both  these  authors  state,  that  although 
the  circulation  was  in  general  comparatively 
slow  in  the  web  of  the  frog's  foot,  still  in  many 
instances  in  this  situation,  and  more  frequently 
in  the  mesentery,  they  were  unable  to  detect 
any  difference  in  the  rapidity  of  the  flow  of  the 
blood  in  the  larger  and  smaller  arteries.* 

Hales,  again,  states  as  the  result  of  his  ob- 
servations and  measurements,  that  the  velocity 
of  the  blood  in  the  smallest  capillaries  of  the 
abdominal  muscles  of  the  frog,  is  so  small  as 
one  or  one  and  a  half  inch  in  a  minute ;  and, 
from  the  attempts  which  we  ourselves  have 
made  at  these  measurements,  we  feel  inclined 
to  agree  with  the  statement  of  this  able  experi- 
menter, having,  upon  several  occasions,  ascer- 
tained that  in  those  capillaries  which  admit 
only  two  globules  of  blood,  the  velocity  is  not 
greater  than  the  hundredth  part  of  an  inch  in  a 
second  ;  but  it  seems  doubtful  whether  in  all 
the  capillaries  the  velocity  is  so  small  as  in 
those  just  alluded  to,  and  in  the  larger  capillary 
vessels  of  the  diameter  of  six  globules,  when 
no  unnatural  obstruction  to  the  circulation  in 
the  limb  occurred,  independently  of  the  diffi- 
culty of  fixing  the  eye  upon  any  globule  in  such 
a  way  as  to  trace  its  progress  along  the  vessel, 
the  velocity  has  always  appeared  so  great  as  to 
prevent  the  possibility  of  measuring  it ;  and  we 
are  at  a  loss  to  conceive  in  what  manner  Haller 
made  the  comparison  he  speaks  of  between  the 
velocity  in  the  larger  and  smaller  arteries.  By 
means  of  the  microscope,  it  is  easy  to  see  that 
the  velocity  is  greater  in  the  small  arteries  than 
in  the  corresponding  veins,  which  are  both 
more  numerous  and  considerably  larger  than 
the  arteries. 

The  results  of  actual  observation  of  the  flow 
of  the  blood  and  of  the  measurement  of  the 
relative  capacities  of  different  arteries,  afford  as 
yet  very  unsatisfactory  data  upon  which  to 
found  an  estimate  of  the  relative  velocity  of  the 
blood  in  the  trunks  and  branches  of  the  arte- 
ries. In  the  absence  of  more  direct  means  of 
calculation,  an  approximative  estimate  may  be 
made  in  another  way,  viz.  by  comparing  the 
quantity  of  blood  which  occupies  a  known 
space  of  the  larger  vessels  with  the  whole  quan- 
tity of  blood  contained  in  the  body. 

We  have  already  seen  that  the  whole  blood 


*  Haller  appears  to  mean  here  arteries  of  consi- 
derable size. 


in  the  body  may  be  estimated  at  nearly  thirty 
pounds :  now,  let  us  suppose  the  aorta  and 
pulmonary  arteries,  together  with  their  return- 
ing veins,  to  form  a  continuous  tube  of  the 
length  of  the  two  courses  of  the  blood,  in  the 
systemic  and  pulmonic  circulations,  and  of  the 
same  diameter  as  these  vessels  at  their  point  of 
junction  with  the  heart;  a  very  simple  calcula- 
tion shews  us  that  such  a  tube  is  capable  of 
holding  only  about  six  pounds  and  a  quarter, 
or  less  than  a  fourth  part  of  the  whole  blood 
of  the  body ;  or  in  other  words,  were  the  aggre- 
gate capacities  of  the  small  vessels  no  more 
than  equal  to  that  of  the  larger,  they  would  be 
capable  of  holding  only  a  fifth  of  the  blood 
contained  in  the  body. 

The' velocity  of  the  blood  in  the  commence- 
ment of  the  aorta  may  be  considered  as  two 
and  a  half  inches  in  a  second,  for  this  is  the 
space  occupied  by  all  the  blood  which  is  pro- 
pelled into  the  aorta  from  the  left  ventricle  in 
that  time,  and  according  to  the  arbitrary  modes 
of  estimating  the  relative  capacity  of  the  aorta 
and  its  branches  here  employed,  the  velocity 
of  the  blood  in  the  aortic  capillaries  generally, 
might  be  considered  as  one-fourth  of  that  in  the 
commencement  of  the  aorta,  or  nearly  half  an 
inch  in  a  second,  a  result  widely  different  from 
that  obtained  by  Hales. 

Attempts  have  also  been  made  to  estimate 
the  velocity  of  the  flow  of  blood,  by  ob- 
serving the  time  which  certain  substances, 
when  introduced  into  one  part  of  the  vascular 
system,  take  to  pass  to  another.  The  most 
remarkable  series  of  experiments  of  this  na- 
ture with  which  we  are  acquainted  were  per- 
formed by  Hering.*  This  author  states  that 
he  has  been  able  to  detect  prussiate  of  potassa, 
which  he  had  introduced  into  one  of  the  jugu- 
lar veins  of  a  horse,  in  the  blood  drawn  from 
the  opposite  jugular  vein  in  the  space  of  from 
twenty  to  thirty  seconds ;  and  he  has  formed 
the  conclusion  from  this  experiment  that  the 
prussiate  of  potass,  in  order  to  gain  the  jugu- 
lar vein  on  the  opposite  side  of  the  body,  had 
passed  in  this  remarkably  short  space  of  time 
through  the  whole  course  of  the  double  circu- 
lation: that  it  was  first  carried  to  the  heart, 
then  passed  through  the  pulmonary  arteries 
and  veins,  and  returned  to  the  heart,  from 
which  it  must  have  been  transmitted  through 
the  ultimate  ramifications  of  the  systemic  ar- 
teries before  being  brought  back  by  the  veins, 
in  which  it  was  found  on  the  opposite  side  of 
the  body.  Hering  states,  as  the  result  of  other 
experiments  of  a  similar  nature  made  upon 
different  bloodvessels,  that  the  prussiate  of 
potassa  passed  from  the  jugular  vein  to  the 
saphena  vein  in  twenty  seconds ;  to  the  mas- 
seteric  artery,  in  fifteen  to  twenty  seconds ;  to 
the  external  maxillary  artery,  in  ten  to  twenty- 
five  seconds ;  to  the  metatarsal  artery,  in  twenty 
to  forty  seconds. 

We  consider  these  curious  experiments  as 
important  in  many  points  of  view,  but  do  not 
feel  inclined  to  concur  in  the  conclusion  de- 
duced from  them  by  their  author,  that  the 

*  Tiedemann's  Zeitschrift,  vol.  iii.  p.  85. 


CIRCULATION. 


66 1 


circulation  of  the  blood,  rapid  as  it  may  be, 
takes  place  in  this  remarkably  short  space  of 
time,  and  we  are  disposed  to  suspect  that  the 
experiments  themselves  are  liable  to  several 
sources  of  fallacy.  The  tendency  of  the  prus- 
siate  of  potass  to  permeate  the  textures  of  the 
body,  more  freely  than  any  other  substance 
known,  has  been  proved  by  many  expe- 
riments, and  it  is  therefore  necessary  that 
Hering's  experiments  should  be  performed  with 
some  other  substances,  before  they  can  be  re- 
garded as  a  correct  means  of  estimating  the 
rapidity  of  the  circulation. 

The  velocity  of  the  blood  is  generally  be- 
lieved to  be  greater  in  the  pulmonic  than  in 
the  systemic  circulation, — an  opinion  founded 
chiefly  on  the  supposed  less  capacity  of  the 
vessels  belonging  to  the  pulmonary  trunks. 
Actual  measurements  of  the  velocity  of  the 
blood  in  the  capillaries  of  the  lungs  of  cold- 
blooded animals  by  Hales,  Spallanzani,  and 
others,  would  seem  to  give  support  to  this 
view,  but  it  must  at  the  same  time  be  re- 
collected that  the  course  through  which  the 
blood  passes  in  the  pulmonary  or  lesser  circu- 
lation, is  considerably  shorter  upon  the  whole 
than  that  of  the  systemic  or  greater, — a  circum- 
stance which  must  diminish  to  a  certain  extent 
the  disproportion  in  the  velocity.* 

b.  Force  of  the  blood  in  the  arteries  and  force 
of'  the  heart. — Another  interesting  inquiry  con- 
nected with  this  subject  relates  to  the  force 
with  which  the  blood  is  impelled  in  the  arte- 
ries, and  the  calculations  that  have  been  made 
of  the  power  of  the  heart  itself,  from  the  ob- 
servation of  the  force  of  the  blood  in  the  arte- 
ries. The  experiments  made  with  a  view  to 
discover  these  forces  appear  sufficiently  simple 
in  their  nature ;  but  the  calculations  founded 
upon  the  experiments  have  differed  so  widely, 
as  to  have  furnished  a  plausible  pretext  for 
throwing  ridicule  on  the  application  of  physical 
laws  to  the  living  animal  functions. 

As  the  arteries  and  other  vessels  are  kept 
distended  with  blood  by  the  action  of  the 
heart,  it  follows  that  were  they  rigid  tubes, 
the  force  of  the  heart  would,  in  accordance 
with  the  laws  of  propagation  of  pressure 
through  fluids,  be  transmitted  without  loss 
through  the  whole  column  of  blood  in  the 
arteries  at  one  and  the  same  moment :  but  in 
consequence  of  their  yielding  to  distension, 
the  force  of  the  heart  operates  upon  the  blood 
only  through  the  elastic  reaction  of  the  coats 
of  the  arteries. 

When  an  opening  is  made  into  one  of  the 
larger  arteries,  the  blood  issues  with  force,  and 
spouts  to  some  distance,  but  the  height  to 

*  In  reference  to  the  above  calculations,  it  must 
also  be  kept  in  mind,  in  the  first  place,  that  the 
estimate  of  tlie  velocity  of  the  blood  in  the  pul- 
monic circulation  in  the  frog  can  scarcely  with 
propriety  be  applied  to  man,  seeing  that  in  the 
frog  the  pulmonary  artery  is  only  a  branch  of  the 
aorta ;  and,  in  the  second  place,  that  in  animals 
with  a  double  circulation,  although  the  quantity 
of  blood  which  leaves  both  sides  of  the  heart  at 
each  systole  be  equal,  it  does  not  necessarily  follow 
that  the  whole  blood  which  circulates  through  the 
system  should  in  the  same  time  pass  through  the 
lungs. 


which  the  blood  rises  when  allowed  to  escape 
from  a  simple  aperture  in  an  artery  varies  from 
many  accidental  circumstances,  and  cannot 
therefore  be  taken  as  affording  an  accurate 
measure  of  the  force  with  which  the  blood 
moves  within  the  vessels. 

Hales  seems  first  to  have  investigated  this 
force  in  a  more  accurate  and  experimental 
manner,  by  observing  the  weight  which  the 
blood  in  one  of  the  arteries  of  a  living  animal 
is  capable  of  sustaining  within  a  tube  adapted 
to  it.  He  remarked  that  the  blood  issuing 
from  a  simple  aperture  in  the  carotid  artery  of 
a  horse  and  directed  upwards  did  not  rise 
above  three  feet,*  but  that  when  the  blood  was 
allowed  to  pass  into  a  long  glass  tube  adapted 
to  the  same  artery  it  rose  very  quickly  to  a 
much  greater  height,  as  to  nearly  ten  feet  in 
some  of  the  experiments.  Hales  performed 
similar  experiments  on  the  arterial  flow  in 
sheep,  oxen,  dogs,  and  other  animals,  and 
after  observing  for  each  the  pressure  which  the 
blood  in  the  arteries  is  usually  capable  of  ex- 
erting, he  endeavoured  to  compute  the  pres- 
sure of  the  blood  in  the  arteries  of  man,  by 
a  comparison  of  the  size  of  his  whole  body  or 
heart  and  bloodvessels  with  those  of  the  other 
animals.  The  pressure  of  the  blood  in  the 
aorta  of  the  horse  being  considered  as  eleven 
pounds,  Hales  estimates  in  the  way  above- 
mentioned  the  force  of  the  blood  in  the  human 
aorta  at  4  Ibs.  6  oz. ;  seven  and  a  half  feet 
being  the  height  to  which  he  supposed  that  the 
blood  would  rise  in  a  tube  connected  with  the 
larger  arteries  of  a  man. 

These  experiments  of  Hales  shewed  in  a 
very  clear  manner,  that  the  height  to  which 
the  blood  rises  in  one  of  the  larger  arteries 
affords  us  the  means  of  ascertaining  directly 
the  amount  of  pressure  which  the  stream  of 
blood  impelled  by  the  heart  through  the  arte- 
ries is  capable  of  exerting  at  any  part  of  the 
arterial  system,  or  in  other  words  it  gives  us  a 
measure  of  the  statical  force  of  the  heart  as  it 
operates  through  the  arterial  tubes.f 

According  to  a  well-known  law  of  physics, 
the  heart  must  be  pressed  upon  in  every  part 
of  its  internal  surface  by  the  column  of  blood 
which  it  has-  raised;  so  that  by  multiplying 
the  area  of  the  internal  surface  of  the  ventricle 
into  the  height  of  the  column  of  blood  sup- 
ported in  the  tube  connected  with  an  artery, 
we  shall  ascertain  the  pressure  which  acts 
backwards  on  the  inner  surface  of  the  heart. 
Hales  estimates  the  inner  surface  of  the  ven- 
tricle of  the  human  heart  at  fifteen  square 
inches,  and  multiplying  the  pressure  of  a  co- 

*  This  experiment  we  have  repeated  with  Mr. 
Dick's  assistance. 

t  These  experiments,  as  well  as  others  subse- 
quently performed,  demonstrate  the  importance  of 
confining  our  researches  in  an  inquiry  of  this  nature 
to  the  estimation  of  the  statical  force  operating  in 
the  organs  of  circulation,  as  the  only  useful  ob- 
ject of  such  calculations, — the  propriety  of  which 
is  also  sufficiently  apparent  from  the  extraordinary 
results  of  the  attempts  to  estimate  the  dynamical 
power  of  the  heart  or  the  whole  force  generated 
in  that  organ  by  muscular  contraction,  by  Borelli 
and  Bernouilli,  the  first  of  whom  calculated  this 
force  to  equal  180,000,  the  second  3,000  Ibs. 


662 


CIRCULATION. 


lumn  of  blood  of  seven  feet  and  a  half  high 
into  the  area  of  the  inner  surface  of  the  heart : 
he  hence  calculates  the  pressure  on  the  in- 
ner surface  of  the  human  heart  to  be  nearly 
51  A  Ibs.  The  pressure  on  the  interior  of  the 
horse's  heart  he  estimates  at  113  Ibs.  upon 
similar  principles. 

As  pressure  applied  in  any  direction  to  a 
fluid  column  is  equally  transmitted  through  all 
its  parts,  and  as  the  blood  in  the  arteries  forms 
continuous  columns  which  all  branch  off  from 
the  aorta,  it  might  a  priori  have  been  con- 
cluded that  the  force  of  the  blood  must  be  the 
same  in  all  the  arteries  of  any  considerable 
size.  Hales,  though  he  does  not  state  this 
proposition  very  explicitly,  seems  yet  to  have 
taken  it  for  granted;  for,  in  estimating  the 
pressure  of  the  heart,  he  takes  into  account 
merely  the  height  of  the  column  without  re- 
ference to  the  size  of  the  artery.  We  shall 
find  this  proposition  to  be  satisfactorily  proved 
to  be  correct  by  direct  experiments  subse- 
quently performed. 

The  experiments  of  Hales  were  liable  to  two 
principal  objections  :  1st,  that  the  coagulation 
of  the  blood  in  the  long  glass  tube  adapted  to 
the  artery  must  have  prevented  its  free  motion  ; 
and,  2nd,  that  the  length  of  the  tube,  besides 
giving  rise  to  the  necessity  of  frequently  re- 
moving it  and  various  other  inconveniences, 
must  have  occasioned  a  considerable  loss  of 
blood  in  filling  from  the  arteries  of  small  ani- 
mals. Both  these  sources  of  fallacy  have  been 
provided  against  most  successfully  by  M. 
Poiseuille,*  an  ingenious  ex- 
perimenter of  Paris,  who,  by 
the  adoption  of  a  simple  con- 
trivance, has  been  enabled  to 
measure  with  great  accuracy 
the  arterial  pressure  of  the  blood, 
and  has  thus  confirmed  and 
extended  the  interesting  re- 
searches of  Hales. 

The  instrument  employed  by 
Poiseuille,  to  which  he  gives 
the  name  of  Hemadynamome- 
ter,    (Jig.  329,) 
consists  of  a  bent 
glass  tube  of  the 
form  here  repre- 
sented, filled  with  mercury  in 
the  lower  bent  part  (a,  rf,  e). 
The  horizontal  part  (6),  provided 
with  a  brass  head,  is  fitted  into 
the  artery,  and  a  little  of  a  solu- 
tion   of   carbonate   of  soda   is 
interposed  between  the  mercury 
and  the  blood  which  is  allowed 
to  enter  the  tube  for  the  pur- 
pose of  preventing  its  coagula- 
tion.    When   the  blood  is  al- 
lowed to  press  upon  the  fluid 
in  the  horizontal  limb,  the  rise 
of   the    mercury    towards    (c) 
measured    from   the    level    to 
which  it  has  fallen  towards  (d) 
gives  the  pressure  under  which 
the  blood  moves. 
*  Magendie's  Journal,  vols.  viii.  &  ix.  Breschet's 
Repert.  d'Anat.  et  de  Physiol.  1826. 


Fig.  329. 

PL 


Poiseuille's  He- 


of  the  most  important  facts  established 
by  Poiseuille's  experiments  is,  that  the  pressure 
of  the  blood  is  within  certain  limits  nearly  the 
same  in  arteries  of  very  different  calibre  and 
at  different  distances  from  the  heart;  as  proved 
by  the  rise  of  the  mercury  of  the  hemadyna- 
mometer  to  nearly  an  equal  height  when  this 
instrument  was  connected  with  the  iliac,  caro- 
tid, radial,  facial,  arid  other  arteries  in  some 
of  the  lower  animals.  It  is  hence  apparent, 
that,  in  order  to  ascertain  the  whole  amount 
of  force  with  which  the  blood  is  propelled 
in  the  aorta,  or  the  statical  force  of  the 
heart  itself,  it  is  sufficient  to  measure  by 
means  of  the  tube  the  momentum  of  the 
blood  in  any  one  of  the  arteries.  Poiseuille 
estimates  the  force  with  which  the  blood  is 
propelled  in  the  commencement  of  the  aorta 
in  man  at  4  Ibs.  3  oz., — a  result  which  agrees 
remarkably  with  that  obtained  by  Hales.* 

Poiseuille,  however,  considers  the  pressure 
backwards  within  the  heart  to  amount  to  13  Ibs. 
only,  as  he  calculates  this  in  a  different  way 
from  that  followed  by  Hales,  viz.  by  multi- 
plying the  pressure  of  the  blood  in  the  aorta 
into  the  surface  of  a  plane  passed  through  the 
base  and  apex  of  the  left  ventricle,— a  mode 
of  calculation  which  it  appears  that  Dr.  Hales 
had  not  lost  sight  of;  for,  at  page  21  of  the 
work  on  Hemastatics,  he  proposes  it  as  the 
"  means  of  estimating  the  force  of  the  blood 
which  the  muscular  fibres  of  the  ventricle  must 
resist." 

Poiseuille  estimates  the  force  with  which  the 
blood  moves  in  the  radial  artery  of  man  at  four 
drachms. 

Hales  had  remarked  that  the  blood  in  the 
tube  connected  with  an  artery  rose  regularly  a 
little  way  at  each  systole  of  the  ventricle,  and 
remained  always  somewhat  higher  during  the 
straining  of  the  animal,  that  is,  while  the 
muscles  of  expiration  were  in  action.  These 
phenomena,  known  to  Haller,  were  demon- 
strated experimentally  by  Magendie,  and  re- 
ceive a  still  more  decided  confirmation  from 
the  experiments  of  Poiseuille  made  with  the 
hemadynamometer.f 

We  would  here  remark  that,  it  having  been 
shewn  by  the  above-mentioned  experiments 
that  the  force  of  the  heart  is  sensibly  the  same 
in  the  trunks  and  larger  branches  of  the  arte- 
ries, it  is  manifest  that  the  angles  of  rami- 
fication and  the  friction  of  the  blood  against 
the  sides  of  the  vessels  can  give  rise  to  very  little 
if  any  diminution  in  the  force  of  the  heart 
transmitted  by  the  elasticity  of  the  arterial 
parietes.  We  shall  afterwards  see  that  the 
case  is  very  different  in  the  smaller  vessels. 

We  would  also  call  the  attention  of  the 
reader  to  an  interesting  application  of  the  fact 
of  the  complete  transmission  of  pressure  through 
the  fluid  contained  within  the  bloodvessels  in 
all  directions,  in  the  immense  force  which  the 

*  The  power  of  the  heart  has  also  been  calcu- 
lated from  the  force  supposed  necessary  to  raise 
the  foot  of  one  of  the  legs  thrown  across  the  other 
in  the  pulsatory  movement  which  is  then  seen  to 
occur, — one  of  the  most  inaccurate  methods  that 
could  be  adopted. 

t  See  Part  IV,  of  this  article. 


CIRCULATION. 


blood  occasionally  appears  to  exert  within  an 
aneurismal  tumour;  giving  rise  to  its  peculiarly 
hard  pulsation  on  every  side,  and  assisting  the 
ravages  by  absorption  which  are  frequently  the 
consequence  of  the  larger  internal  aneurisms. 
The  pressure  in  an  aneurism  is  obviously  to  be 
measured  by  the  extent  of  its  internal  surface 
multiplied  into  the  force  with  which  the  blood 
moves  in  the  part  of  the  artery  where  it  opens 
into  the  aneurismal  sac. 

c.  Arterial  pulse. — The  arterial  pulse,  or  suc- 
cession of  beats  felt  by  the  finger  placed  over 
an  artery,  depends  upon  the  impulse  of  the 
left  ventricle  being  communicated  along  the 
arterial  tube  and  the  column  of  blood  which 
it  contains. 

When  a  ligature  is  put  upon  an  artery,  no 
pulse  is  felt  beyond  the  place  where  the  artery 
is  obstructed,  but  it  is  distinct  up  to  that  place. 
This  experiment  at  once  shews  the  dependence 
of  the  pulse  on  the  systole  of  the  ventricle, 
and  establishes  that  this  phenomenon  is  not 
dependent  on  the  progressive  motion  of  the 
blood,  since,  in  that  part  of  the  artery  placed  on 
the  side  of  the  ligature  next  to  the  heart  in  which 
the  pulse  is  distinct,  the  blood  is  at  rest.  Nor 
does  the  pulse  appear  in  ordinary  circumstances 
to  depend  upon  lateral  distension  of  the  arteries, 
for  such  distension  occurs  to  so  small  a  degree 
as  is  quite  insufficient  to  account  for  the  produc- 
tion of  the  pulse.  Arthaud,*  a  French  surgeon, 
was  the  first  who  sustained,  in  opposition  to 
the  opinion  prevalent  at  the  time  he  wrote, 
the  view  that  the  arteries  are  not  laterally  di- 
lated at  each  systole  of  the  heart,  and  that  the 
pulse  is  not  to  be  explained  by  such  dilatation. 
Arthaud  shewed  that  when  an  artery  is  laid 
bare,  no  perceptible  enlargement  of  its  calibre 
takes  place  at  the  time  when  the  heart  con- 
tracts and  the  pulse  is  felt.  We  have  already 
stated  that  the  arterial  system  being  fuller  of 
blood  at  one  time  than  another  must  be  dilated 
to  admit  the  blood  propelled  into  the  aorta 
from  the  ventricle;  and  it  seems  to  follow 
from  the  observations  of  Arthaud,  which  have 
been  ably  confirmed  by  the  interesting  expe- 
riments of  the  late  Dr.  Parry,t  that  the  en- 
largement of  the  capacity  of  the  arteries  is 
effected  principally  by  their  elongation.  Ac- 
cording to  these  experimenters,  when  one  of 
the  larger  arteries  is  laid  bare,  the  eye  does  not 
distinguish  any  lateral  enlargement  corres- 
ponding to  the  systole  of  the  ventricle,  and 
Parry  measured  with  great  care  the  artery 
at  the  time  of  each  pulse  and  between  the 
beats  without  being  able  to  detect  the  slightest 
differences  in  its  size  ;  but  though  not  percep- 
tibly distended  laterally,  the  artery  undergoes 
a  certain  change  of  place,  for  at  each  systole 
of  the  ventricle  it  is  propelled  in  a  direction 
outwards  from  the  heart,  and  during  the  di- 
astole it  returns  to  its  former  situation.  This 
locomotion  of  the  artery,  as  it  is  called,  is 

*  Dissert,  sur  la  Dilatation  des  A  rteres.  Paris, 
1770. 

t  Dr.  C.  H.  Parry's  Inquiry  into  the  Nature  of 
the  Arterial  Pulse.  Bath  and  Lond.  1816.  Dr. 
Chas.  Henry  Parry's  Additional  Experiments. 
Lond.  1819. 


CG3 
distension    and 


obviously  produced  by  the 
elongation  of  the  larger  arteries  near  the  heart. 
A  considerable  elongation  of  the  arteries  may 
also  easily  be  seen  at  all  sudden  incurvations  of 
these  vessels.  The  bend  of  the  curved  part  is 
generally  increased  and  projected  further  out- 
wards during  the  systole;  and  we  observe  that  a 
straight  part  of  an  artery,  if  fixed  at  its  opposite 
ends,  is  bent  at  the  time  of  the  pulse  in  conse- 
quence of  its  elongation.  In  many  persons  in 
a  state  of  health  the  arteries  may  be  seen  to 
move  under  the  skin,  although  not  exposed. 
This  motion  is  generally  perceived  at  places 
where  there  is  a  sudden  bend  of  an  artery,  or 
where  the  artery  lies  upon  an  unyielding  part, 
as  bone,  &c.,  and  in  some  individuals  an  ap- 
pearance of  dilatation  or  lateral  enlargement 
even  may  be  perceived  in  some  of  the  larger 
arteries.  Although  these  circumstances  shew 
that  the  pulse  is  not  attributable  to  a  lateral 
dilatation  of  arteries,  yet  it  would  appear  that 
such  an  enlargement  does  occur  in  a  small 
degree,  for  it  is  occasionally  perceptible  to  the 
eye  in  the  arteries  when  laid  bare ;  and  M. 
Poiseuille,*  by  means  of  a  small  apparatus, 
capable  of  being  applied  round  a  part  of  an 
artery,  has  proved  distinctly  the  occurrence  of 
lateral  enlargement,  and  estimated  its  extent 
in  the  larger  arteries  at  1-1 1th  of  their  dia- 
meter. 

The  finger  laid  upon  an  exposed  artery  does 
not  feel  any  pulse,  unless  the  artery  be  com- 
pressed, and  when  the  arteries  are  in  their  na- 
tural situation  covered  by  the  integuments,  it  is 
only  when  they  lie  upon  a  hard  part,  as  a  bone, 
and  when  the  sides  of  the  artery  are  brought 
nearer  to  one  another  by  pressure,  that  the 
pulse  is  perceptible.  Those  instances  in  which 
this  does  not  appear  to  be  the  case,  as  well  as 
those  in  which  the  dilatation  occasionally  seems 
to  occur  below  the  integuments,  may  in  like 
manner  depend  upon  the  artery  being  subjected 
to  pressure  of  superjacent  parts  at  the  place  ob- 
served. It  is  also  sufficiently  obvious  that  the 
pulse  does  not  depend  upon  any  active  change  of 
the  artery  itself,  or  upon  any  vital  contraction 
and  dilatation  of  the  vessels,  for  the  exact  appear- 
ance of  the  living  pulse  maybe  produced  in  the 
arteries  of  a  dead  animal  by  injecting  water 
into  the  arteries  with  a  syringe,  if  care  be  taken 
to  imitate  with  the  strokes  of  the  piston  the 
beats  of  the  left  ventricle  of  the  heart.  A  fur- 
ther proof  of  this,  and  an  excellent  illustration 
of  the  nature  of  the  pulse,  is  obtained  from  the 
curious  experiment  performed  by  Bichat  of 
connecting  the  bloodvessels  of  a  living  animal 
with  those  of  a  dead  one,  the  result  of  which  is 
the  production  of  a  pulse  in  the  vessels  of  the 
dead  animal  connected  with  the  arteries  of  the 
living  one.  In  those  instances  in  which  a 
communication  has  been  established  between 
an  artery  and  a  contiguous  vein  in  consequence 
of  a  wound,  or  in  what  is  called  Aneurismal 
Varix,  the  vein  pulsates  exactly  like  an  artery. 

Many  have  remarked  that  the  pulse  in  the 


Journ. 
1828. 


ager 
vol.   ix.    p.   44;    and   Breschet's  Repert 


664 


CIRCULATION. 


arteries  of  the  extremities  is  a  little  later  than 
the  beat  of  the  heart  on  the  ribs  and  the  pulse 
in  the  arteries  in  the  immediate  neighbourhood 
of  the  heart.  This  retardation  has  of  late  been 
more  distinctly  pointed  out  by  Dr.  M'Donnell 
of  Belfast,*  and  by  Weber  of  Leipsig.f  It  is 
much  more  marked  in  some  persons  than  in 
others,  and  is  always  most  perceptible  when 
the  circulation  is  slowest.  With  a  little  atten- 
tion we  can  thus  observe  a  distinct  succession 
in  the  occurrence  of  the  beat  of  the  apex  of  the 
heart  at  the  ribs,  the  pulse  in  the  carotid, 
facial,  radial,  and  posterior  tibial  arteries,  the 
interval  between  each  of  which,  though  very 
small,  being  yet  appreciable  by  the  finger. 
Weber  states  that  the  retardation  of  the  pulse 
in  the  foot  after  that  of  the  beat  of  the  heart 
amounts  to  not  more  than  one-seventh  part  of 
a  second.  We  have  ourselves  confirmed  by 
experiments  on  several  individuals  the  most  of 
these  facts  relating  to  the  later  pulse  in  the 
more  remote  arteries.  The  cause  of  the  retar- 
dation is  obviously  the  elasticity  and  yielding 
of  the  arterial  parietes  ;  for  were  the  arteries 
rigid  tubes,  it  is  manifest  that  the  impulse  of 
the  heart  would  be  felt  at  one  and  the  same  in- 
stant of  time  throughout  the  whole  of  the 
branches ;  but  as  these  vessels  yield  to  disten- 
sion, that  part  of  them  to  which  the  distending 
force  is  immediately  applied  is  first  dilated, 
and  this  dilatation  does  not  reach  immediately 
the  remote  parts. 

The  pulse  has  been  correctly  compared  to 
the  propagation  of  an  undulation  or  wave  on 
the  surface  of  water;  for  the  successive  im- 
pulses of  the  heart  are  first  given  to  the  column 
of  blood  in  the  commencement  of  the  aorta; 
this  column  communicates  these  impulses  to 
the  arterial  parietes  and  tends  to  distend  them. 
The  parietes  re-act  against  this  distending  force 
and  compress  the  adjoining  part  of  the  column 
of  blood,  from  which  the  impulse  passes  to  the 
next  part  of  the  aorta;  and  so  the  pulse,  gradu- 
ally passing  on  from  the  trunks  to  the  smaller 
branches,  becomes  less  and  less  perceptible  as 
the  force  of  the  heart  is  equalized  by  the  elastic 
resistance  of  the  coats  of  these  vessels.} 

The  pulse  is  still  perceptible  in  very  small 
arteries  :  Haller§  states  that  he  was  unable  to 
perceive  any  in  small  arteries  of  one-sixth  of  a 
line  in  diameter, — an  observation  which  does 
not,  however,  prove  the  flow  of  the  blood  to  be 
uniform  or  without  jerks  even  in  vessels  of 
this  size,  for  Spallanzani||  observed  pulsations 
in  arteries  of  this  small  size;  and  the  microsco- 
pic observation  of  the  circulation  in  transparent 
parts  by  Haller  himself,  Spallanzani,  and 
others,  shews  that  the  visible  impulse  of  the 

*  At  the  Meeting  of  the  British  Scient.  Associat. 
in  Dublin. 

t  De  pulsu  in  omnib.  arter.  plane  non  synchro- 
nico.  Annot.  Academ.  Leipzig,  1834. 

$  Young's  Croonian  Lecture  on  the  Functions  of 
the  Heart  and  Arteries,  in  his  Introduction  to  Me- 
dical Literature. 

§  Mem.  sur  le  Mouvement  du  Sang.  Laus.  1756. 
Translated. 

||  Exper.  sur  la  Circulation,  in  French,  by  Tour- 
des.  Paris,  An  8.  In  English,  by  Hall.  Lond. 


heart  is  communicated  to  the  blood  in  the 
smallest  of  those  vessels,  which  have  distinctly 
the  characters  of  arteries. 

The  pulse  being  nothing  else  than  the  beats 
of  the  heart  transmitted  through  the  arteries, 
the  consideration  of  the  variations  in  force  or 
frequency  to  which  it  is  subject  belongs  more 
properly  to  the  subject  of  the  functions  of  the 
heart.  In  this  place  we  shall  only  mention 
the  mean  of  the  usual  number  of  pulsations  of 
the  arteries  in  the  space  of  a  minute  as  they 
occur  at  different  periods  of  life. 

Child  before  birth    140—150 

Newly-born  infant      1 30 — 1 40 

Child  one  year  old 120 

Two  years 108 

Three  years 95 

Seven  years 85 

Age  of  puberty 80 

Manhood 75 

Old  age    60—50 

d.  Vital  properties  of  the  arteries. — In  the 
view  we  have  hitherto  taken  of  the  arterial  circu- 
lation we  have  considered  the  coats  of  the  arte- 
ries as  endowed  with  physical  powers  only,  and 
we  have  alluded  to  no  other  phenomena  of  the 
motion  of  the  blood  than  those  which  appear 
to  be  connected  with  their  elasticity.  We  have 
now  to  direct  our  attention  to  the  more  strictly 
vital  and  contractile  powers  of  the  arteries, 
which  constitute  them  an  independent  source 
of  force,  and  to  examine  how  far  the  operation 
of  such  powers  may  modify  the  flow  of  the 
blood.  We  shall  here  discuss  more  in  detail 
the  questions  whether  the  heart  is  to  be  regard- 
ed as  the  only  source  of  the  power  by  which 
the  blood  is  impelled,  and  the  bloodvessels 
merely  as  the  modifiers  or  regulators  of  the 
force  generated  by  the  heart's  contraction — or 
whether  the  arteries  do  not,  by  their  own  inde- 
pendent power,  contribute  to  the  propulsion  of 
the  blood. 

Physiologists  are  very  much  divided  in  their 
opinions  upon  these  questions,  some  regarding 
the  heart  as  the  sole  moving  power,  some  suppo- 
sing the  bloodvessels  to  be  the  principal,  the 
heart  a  subordinate  cause  of  motion;  and  others 
adopting  various  modifications  of  these  oppo- 
site views.  Many  who  agree  in  considering 
the  heart's  action  as  insufficient  to  propel  the 
blood  through  the  smaller  bloodvessels  into  the 
veins,  differ  as  to  the  cause  of  the  additional 
power  supposed  necessary  for  the  maintenance 
of  the  circulation  ;  the  larger  and  middle  sized 
arteries  being  looked  upon  by  some  as  highly 
contractile,  and  in  consequence  of  this,  the 
agents  of  propulsion ;  the  capillaries  being  re- 
garded by  others  as  the  most  efficient  promoters 
of  the  flow  of  the  blood  within  the  bloodves- 
sels. We  must,  for  the  present,  confine  our 
remarks  to  the  first  of  these,  or  the  opinion  that 
the  larger  arteries  are  mainly  or  in  part  the 
agents  of  the  propulsion  of  the  blood. 

That  the  arteries  have  the  power  of  changing, 
to  a  certain  extent,  the  quantity  of  blood  which 
passes  through  them,  and  of  thus  modifying  the 
circulation  by  their  own  independent  powers, 
there  can  be  no  doubt,  from  the  occurrence  of 
unequal  distributions  of  blood,  or  of  local  de- 


CIRCULATION, 


665 


terminations  of  that  fluid  which  take  place  in 
blushing,  inflammation,  and  other  states  of  the 
economy  in  which  particular  parts  of  the  vas- 
cular system  become  more  or  less  filled  with 
blood  than  usual ;  for  such  variations  in  the 
distribution  of  the  blood  would  be  impossible, 
were  an  alteration  in  the  powers  of  the  heart 
alone  the  only  means  of  modifying  the  circula- 
tion. The  questions,  however,  whether  such 
powers  as  are  possessed  by  the  arteries  contri- 
bute upon  the  whole  to  the  progressive  motion 
of  the  blood  or  modify  only  its  distribution, 
are  quite  distinct  from  one  another. 

In  its  anatomical  structure  the  fibrous  coat 
of  the  arteries  differs  considerably  from  muscu- 
lar substance,  and  appears  to  resemble  more 
nearly  the  yellow  elastic  ligamentous  tissue. 
Its  fibres  are  less  mixed  with  cellular  substance 
than  those  of  muscles  ;  they  are  also  more  dry, 
hard,  and  friable,  less  coloured,  and,  accord- 
ing to  Hodgkin  and  Lister,*  are  destitute  of 
those  transverse  striae  or  lines  observed  by  the 
microscope  in  ordinary  muscular  fibres.  The 
chemical  constitution  of  the  middle  coat  of  the 
arteries  differs  also  from  that  of  muscle,  for  it 
is  less  soluble  in  acetic  acid,  and  more  easily 
so  in  mineral  acids,  and  it  is  believed  by  Ber- 
zelius  and  Young  not  to  contain  the  animal 
principle,  fibrine,  peculiar  to  muscular  flesh. 
Although  we  fully  admit  the  importance  of 
these  observations  as  establishing  anatomical 
and  chemical  distinctions  between  muscular 
substance  and  the  texture  of  the  middle  coat  of 
the  arteries,  they  do  not  appear  to  us  to  warrant 
the  conclusion  too  hastily  deduced  from  them 
by  some,  that  this  coat  cannot  be  irritable,  or 
does  not  possess  any  of  the  same  properties  as 
muscle,  the  existence  or  non-existence  of  which 
must  be  ascertained  principally  by  physiologi- 
cal evidence.  For  the  transverse  striae  cannot 
be  considered  as  characteristic  of  all  muscular 
fibres;  and  were  we  to  reason  in  this  way 
from  the  result  of  anatomical  observations 
only,  we  should  be  necessitated  to  deny  the 
irritability  of  various  other  textures,  the  con- 
tractility of  which  from  stimulation  or  without 
it,  is  universally  admitted,  although  anatomists 
have  not  yet  detected  muscular  fibres  in  them. 

The  coats  of  the  smaller  arteries  are  generally 
believed  to  be  proportionally  thicker  than  those 
of  the  larger  trunks,  and  John  Hunter  held  the 
opinion  that  the  yellow  fibrous  tissue  exists  in 
greatest  quantity  in  the  larger  arteries ;  while 
the  smaller  vessels,  considered  more  active,  are 
composed  of  a  substance  more  nearly  allied  to 
muscular  fibre.  The  grounds  upon  which  the 
latter  opinion  rests  are  upon  the  whole  not  very 
satisfactory ;  and  it  appears  to  be  opposed  by 
those  instances  in  which,  after  the  closure  by 
ligature  of  the  principal  artery  of  a  limb,  the 
smaller  collateral  vessels  which  maintain  the 
circulation,  after  undergoing  a  rapid  enlarge- 
ment, assume  the  structure  and  general  appear- 
ance of  the  large  arteries. 

The  irritability  of  the  smaller  arteries,  now 
very  generally  admitted  by  physiologists,  though 

*  Appendix  to  the  Transl.   of  Edwards's  Work 
on  the  Influence  of  Physical  Agents,  &c.  p.  443. 
VOL.  I. 


it  seems  by  some  to  have  been  inferred  from 
analogy,  and  to  have  been  rendered  probable 
by  Dr.  Wilson  Philip's  observations  on  the 
effect  of  chemical  stimuli  in  removing  the 
dilated  state  of  the  capillaries  in  inflammation, 
was  first  distinctly  proved  experimentally  by  Dr. 
Thomson  of  Edinburgh,*  who  caused  the  arte- 
ries in  the  web  of  the  frog's  foot  to  contract 
powerfully  by  the  application  of  mechanical 
irritation  as  well  as  by  chemical  stimuli.  His 
experiments  shewed  that  the  nature  of  the  con- 
traction produced  by  stimulation  of  one  of  the 
smaller  arteries  varies  considerably,  occupying 
sometimes  a  greater  or  less  space  of  the  vessel, 
and  being  at  other  times  confined  to  one  place, 
sudden,  and  frequently  so  great  as  completely 
to  stop  the  passage  of  blood.  They  also  de- 
monstrated the  fact  that  the  contraction  of  the 
small  arteries  does  not  follow  immediately  the 
application  of  the  stimulus,  as  occurs  in  the 
voluntary  muscles,  but  that  a  period  of  from 
one  to  three  minutes  elapses  before  the  contrac- 
tion begins,  and  that  the  vessel  remains  con- 
stricted for  some  time,  and  then  returns  to  its 
original  state,  unless  inflammation  shall  have 
occurred,  in  which  case  it  dilates  to  a  greater 
size  than  natural.  The  irritability  of  the  small 
vessels  has  been  fully  established  by  experi- 
ments similar  to  those  of  Dr.  Thomson,  by  Dr. 
Wilson  Philip,f  Dr.  Hastings,}  Kaltenbrun- 
ner,§  and  Wedemeyer,§  the  last  of  whom  suc- 
ceeded in  causing  the  small  arteries  to  contract 
by  means  of  galvanic  as  well  as  of  mechanical 
irritation.  The  constriction  which  follows  the 
injection  of  styptic  and  irritating  fluids  into  the 
arteries,  observed  by  Hales||  in  animals  recently 
dead,  and  similar  experiments  by  Wedemeyer, 
may  be  adduced  as  another  proof  of  their  irrita- 
bility. The  stoppage  of  hemorrhage  from  cuts 
of  the  small  arteries  and  capillaries,  assisted  as 
it  is  by  cold  or  irritating  applications,  may  be 
regarded  as  the  effect  of  the  same  property. 

Contractions  do  not  occur  so  readily  or  ob- 
viously in  the  large  as  in  the  very  small  arte- 
ries. Verschuir  appears  to  have  been  the  first 
•who  observed,  in  a  manner  not  liable  to  fallacy, 
distinct  contractions  of  the  larger  arteries  to 
occur  after  the  direct  application  of  a  stimulus. 
From  an  extended  series  of  experiments  upon 
this  subject,  described  in  his  Inaugural  Disser- 
tation De  Vi  Arteriarum  Contractili,  Verschuir 
was  led  to  adopt  the  opinion  that  the  arteries 
are  possessed  of  irritability,  or  contract  in  the 
same  manner  as  muscles  do  from  irritation ;  as 
he  observed  very  obvious  and  powerful  con- 
tractions to  occur  when,  by  means  of  a  sharp 
point  or  chemical  stimuli,  he  irritated  the  coats 
of  the  larger  arteries  of  animals. 

Ilaller,  though  considering  the  middle  coat 

*  Lect.  on  Inflammation.     Ediu.  1813. 

t  Introduct.  to  the  second  part  of  his  work  on 
Fever. 

J  Introdact.  to  his  work  on  the  Inflammation  of 
the  Mucous  Membrane,  &c. 

§  Expei .  circa  statum  Sang,  et  Vasor.  in  Inflam- 
matione.  Munich,  1826. 

||  Untersuch.  iiber  den  Kreislauf  des  Blutes,  &c. 
Hannover,  1828.  See  also  Koch  in  Meckel's  Archiv. 
1832,  p.  121. 

^1    Statical  Essays,  ii.  p.  124. 

2  X 


666 


CIRCULATION. 


of  the  arteries  as  of  a  muscular  nature,  was  un- 
successful in  producing  obvious  contractions  in 
them.  The  repetition  of  the  experiments  of 
Verschuir  by  many  others  has  been  attended 
with  very  various  results ;  some  confirming  his 
observations,  others  having  entirely  failed  in 
producing  any  obvious  contraction,  or  not  being 
disposed  to  consider  it  of  a  muscular  kind. 
Among  the  last  may  be  mentioned  Nysten, 
Bichat,  Wedemeyer,  and  J.  Miiller. 

It  must  be  obvious  that,  laying  aside  the 
difference  of  opinion  regarding  the  nature  of 
the  contractions  when  they  are  admitted  to 
occur,  in  a  question  of  this  kind  a  positive  re- 
sult deserves  more  consideration  than  a  nega- 
tive one,  provided  the  phenomena  stated  to 
have  been  observed  are  such  as  to  be  appre- 
ciable by  all.  Among  the  experiments  favour- 
able to  the  view  that  the  large  arteries  are  en- 
dowed with  irritability,  may  be  mentioned  those 
described  by  Hastings,*  and  a  series  of  unpub- 
lished observations  by  Dr.  Thomson,  to  which 
we  have  access,  which  seem  to  prove  in  a  very 
satisfactory  manner  the  frequent  occurrence  of 
contractions  in  the  larger  arteries  after  stimula- 
tion ;  and  to  point  out  as  a  cause  of  the  failure 
of  some  at  least  of  the  previous  experiments, 
the  long  time  which  commonly  elapses  between 
the  application  of  the  stimulus  and  the  occur- 
rence of  the  contraction ;  together  with  the  cir- 
cumstances formerly  remarked  by  Verschuir, 
that  the  contraction  is  not  an  invariable  conse- 
quence of  the  stimulation,  and  that  it  occurs 
much  more  readily  in  some  animals  than  in 
others. 

According  to  Dr.  Thomson  the  contraction 
of  the  larger  arteries  is  in  general  not  percepti- 
ble before  from  three  to  ten  minutes  after  the 
application  of  the  stimulus.  When  galvanism 
is  "used,  the  shocks  need  not  be  strong,  but 
must  be  frequently  repeated  in  order  to  induce 
contraction. 

Many  have  remarked  the  gradual  or  sudden 
contraction  of  the  trunks  of  arteries  which  have 
been  laid  bare  in  Man  as  well  as  in  the  lower 
animals.  When  exposed,  an  artery  is  some- 
times equally  contracted  for  some  length  along 
its  tube ;  at  other  times  its  surface  assumes  a 
waved  appearance  from  the  occurrence  of  irre- 
gular contractions  or  alternate  contractions  and 
dilatations,  and  not  unfrequently  the  coat  of 
the  artery  is  much  constricted  at  one  point 
only,  as  if  a  tight  cord  had  been  passed  round 
it.  Appearances  of  this  kind,  which  seem  to 
indicate  very  distinctly  the  possession  of  the 
property  of  irritability  by  the  arteries,  are  well 
known  to  many  surgeons ;  they  were  noted  by 
Drs.  Jones  and  Thomson,  in  "the  experiments 
upon  which  Dr.  Jones's  work  on  Hemorrhage 
was  founded ;  and  also  by  Dr.  Parry,  who 
nevertheless  refuses  to  consider  them  as  irri- 
table contractions.  At  p.  74  of  his  work 
on  the  Powers  of  the  Arteries,  Dr.  Parry, 
referring  to  Experiment  13th,  says,  "  thus  a 
very  narrow  ring  of  the  carotid  became,  while 
it  was  under  examination,  contracted  as  if  a 

*  Inaug.  Dissertat.  Edin.  1817,  et  loc.  cit.  See 
also  Hunter  on  the  Muscularity  of  the  Arteries, 
Edin.  Med.  and  Surg,  Journ.  xxii.  p.  256. 


small  ligature  had  been  half  tightened  around 
it.'7  So  also  in  Experiment  24th,  he  relates 
that  a  part  of  the  carotid  artery  of  a  ewe  was 
diminished  by  a  third  of  its  original  diameter 
underexposure,  after  having  been  half  an  hour 
denuded,  while  the  neighbouring  parts  had  be- 
come rather  dilated,  and  that  while  he  was  pro- 
ceeding to  measure  one  of  these  dilated  por- 
tions, he  "  saw  it  shrink  to  nearly  the  same 
size  as  the  constricted  part."  It  appears  to  us 
manifest,  that,  whether  these  irregular  diminu- 
tions of  the  diameter  of  the  artery,  obviously 
occasioned  by  a  shortening  of  its  fibres,  are  at- 
tributed to  the  exposure  of  the  artery  to  the  air, 
or  the  violence  done  during  the  dissection  of  it 
by  the  scalpel,  they  must  equally  be  regarded 
as  the  consequence  of  stimulation  of  one  kind 
or  other,  and  are  therefore  of  the  nature  of  mus- 
cular contractions. 

Hoffmann  first  noticed  the  contractions  of 
the  arteries  from  the  application  of  acrid  che- 
mical stimuli  to  their  coats;  and  it  appears 
from  numerous  subsequent  experiments,  that 
contractions  are  more  readily  induced  in  this 
than  in  any  other  way.  Were  there  no  other 
proofs  of  the  contractility  of  the  arteries  than 
those  derived  from  the  effect  of  chemical 
agents,  we  should  not  feel  inclined  to  place 
much  reliance  on  them,  on  account  of  the  pos- 
sibility of  there  having  been  induced  a  perma- 
nent alteration  of  the  texture  from  chemical 
action ;  but  the  results  of  such  experiments 
form  an  important  confirmation  of  those  which 
are  performed  with  mechanical  and  galvanic 
irritation.  We  cannot,  however,  acquiesce  in 
the  opinion  of  Wedemeyer*  and  others  who 
compare  the  distinct  and  well-marked  contrac- 
tions of  particular  parts  of  the  arterial  tubes, 
such  as  those  above  alluded  to,  to  the  general 
constriction  of  other  textures,  and  more  parti- 
cularly to  the  shrinking  of  the  skin  which 
occurs  from  the  influence  of  cold,  passions  of 
the  mind,  &c. 

From  these  considerations  we  are  induced  to 
adopt  the  opinion  that  the  contractions  which 
under  certain  circumstances  occur  in  the  ar- 
teries resemble  muscular  contractions  more 
nearly  than  any  other  vital  phenomenon.  The 
positive  evidence  of  direct  experiment  obviously 
proves  that  the  contractions  in  general  follow 
the  application  of  some  stimulus  to  the  artery ; 
but  these  contractions  differ  from  that  of  mus- 
cular parts  chiefly  in  the  length  of  time  which 
elapses  after  the  application  of  the  stimulus 
before  the  change  of  size  begins,  in  the  slow- 
ness with  which  the  contraction  is  succeeded 
by  relaxation,  and  in  the  want  of  obvious  cor- 
respondence between  the  force  of  the  stimulus 
and  the  extent  of  contractions  which  follow  it. 

Besides  the  more  marked  contractions  of 
parts  of  their  tubes,  the  arteries  are  subject  in 
various  circumstances  to  undergo  a  slow  and 
gradual  diminution  of  their  diameter  through- 
out their  whole  length,  which  is  considered  by 
many  physiologists  to  indicate  the  possession 
by  them  of  a  property  of  the  nature  of  contrac- 
tility different  from  irritability  in  its  pheno- 

*  Loc.  cit. 


CIRCULATION. 


607 


men  a  and  the  causes  which  call  it  into  action. 
A  power  of  a  similar  kind,  to  which  the  name 
of  Tonicity  is  applied,  is  believed  to  reside  in 
the  voluntary  muscles.* 

The  experiments  and  observations  generally 
stated  in  proof  of  the  tonic  power  of  arteries 
are  the  following:  — 

1.  When  a  ligature  is  placed  upon  an  artery 
of  a  living  animal,  the  part  of  the  artery  beyond 
the  ligature  becomes  gradually  smaller,  and  is 
emptied  to  a  certain  degree,  if  not  completely, 
of  the  blood  it  contained. 

2.  When  a  part  of  an  artery  in  a  living  ani- 
mal is  isolated  from  other  organs  by  means  of 
two  ligatures  and  punctured,  the  blood  issues 
from  the  orifice,  and  the  enclosed  portion  of 
artery  is  nearly  completely  emptied  of  its  con- 
tents. 

3.  The  empty  condition  of  the  arteries  gene- 
rally found  after  death  is  believed  to  be,  in 
part  at  least,  produced  by  a  slow  contraction 
of  the  whole  of  the  large  arterial  tubes ;  for  it 
has  been  observed,  that  some  hours  after  death 
the  arteries  are  much  diminished  in  size,  and 
this  occasionally  to  such  an  extent  as  to  be 
rendered  impervious,  as  was  observed  in  the 
umbilical  arteries  of  the  navel  string  by  John 
Hunterf  and  others. 

4.  It  has  been  shewn  by  PoiseuilleJ  that 
when  a  portion  of  an  artery  from  an  animal 
recently  dead,  and  one  from  an  animal  that 
has  been  dead  for  some  days,  are  distended 
with  an  equal  force,  the  portion  of  the  artery 
from  the  recently  dead  animal  becomes  more 
contracted  after  the  distending  force  is  removed 
than  the  other  one. 

5.  In  the  last  place,  when  a  large  artery  is 
divided,  the  cut  extremities  frequently  become 
so  completely  constricted  as  wholly  to  prevent 
the  issue  of  blood,  and  this  kind  of  contrac- 
tion is  well  known  to  occur  in  a  greater  degree 
after  laceration  of  an  artery  than  after  division 
by  the  knife :  hence  the  less  danger  to  be  ap- 
prehended from  hemorrhage  in  lacerated  than 
in  incised  wounds ;  and  thence  the  possibility 
of  producing  the  closure  of  one  of  the  larger 
arteries  by  the  mere  compression  or  torsion  of 
its  cut  end. 

In  the  three  last-mentioned  proofs  of  to- 
nicity  the  contraction  of  the  artery  followed 
the  application  of  some  kind  of  irritation  ;  for 
the  exposed  artery  was  dissected  out  by  the 
scalpel,  and  ligatures  were  tightened  round  it, 
the  coats  of  the  artery  were  stimulated  by  dis- 
tension in  Poiseuille's  experiment,  and  in  the 
twisting  or  torsion  as  well  as  in  the  division  of 
an  artery  by  laceration  or  cutting  there  is  always 
an  irritation  applied  to  the  contracting  part. 
The  tonicity  or  tonic  contractility  therefore  was 
in  some  of  these  instances  first  called  into  ope- 
ration and  in  others  increased  by  irritation,  and 
ought  not  therefore  to  be  distinguished  from 
irritability  as  regards  its  cause,  but  only  as 
relates  to  its  phenomena. 

The  evacuation  of  the  blood  from  arteries 

*  Parry,  loc.  citat. 

t  On  the  Blood  and  on  Inflammation. 

$  Magendie's  Journ.  vol.  viii. 


beyond  the  place  at  which  they  have  been  tied 
in  the  living  body,  and  the  contraction  of  ar- 
teries which  takes  place  in  the  dead  body,  as 
well  as  the  rigidity  of  muscles  soon  after  death, 
or  their  retraction  when  divided  in  the  living 
body,  all  seem  to  indicate  a  tendency  in  ir- 
ritable parts  to  undergo  a  slow  and  continued 
contraction  during  the  persistance  of  their  vital 
powers.  This  tendency  to  contraction  seems 
to  differ  from  the  shortening  and  subsequent 
relaxation  which  are  the  more  or  less  imme- 
diate effects  of  stimulation  in  truly  irritable 
parts,  and  it  seems  to  be  more  dependent  upon 
the  removal  of  the  forces  by  which  the  parts  in 
which  it  occurs  are  kept  in  a  state  of  distension 
than  upon  any  other  cause. 

It  is  obviously  in  consequence  of  this  ten- 
dency to  contract  when  not  distended  by  a 
force  from  within,  that  the  arteries  are  always 
nearly  accommodated  to  the  quantity  of  blood 
contained  in  them.  But  while  we  are  con- 
strained to  admit  the  existence  of  the  peculiar 
slow  contractile  power  in  arteries  appropri- 
ately denominated  tonicity,  we  would  caution 
the  accurate  physiologist  against  considering 
as  the  effect  of  this  property  rather  than  of  irri- 
tability any  of  those  contractions  of  the  arterial 
tubes  which  are  induced  or  increased  by  me- 
chanical, galvanic,  or  other  stimuli. 

e.  Influence  of  the  vital  powers  of  the  arte- 
ries on  the  circulation. — Let  us  now  inquire  in 
what  manner  the  flow  of  the  blood  is  influ- 
enced by  the  irritability  and  tonicity  of  the 
arteries. 

Some  of  those  who  have  regarded  the  arteries 
as  contributing  by  their  active  powers  to  propel 
the  blood  have  conceived  it  sufficient  for  them 
to  prove  that  there  is  a  necessity  for  some 
additional  force  in  the  circulation  besides  that 
of  the  heart,  in  consequence  of  the  total  ex- 
penditure of  the  heart's  force  from  the  windings 
of  the  small  vessels,  the  friction  of  the  blood 
against  the  side,  and  other  resistances  to  be 
overcome  in  the  capillary  system.  This  expen- 
diture of  the  heart's  power  admitted  by  many 
on  insufficient  grounds  has  been  very  generally 
overrated.  Although  the  causes  just  men- 
tioned may  diminish  to  a  certain  extent  the 
propelling  power  of  the  heart,  there  are  various 
very  simple  experiments  which  shew  that  the 
heart's  action  is  propagated  with  a  propelling 
effect  through  the  whole  vascular  system,  so  as 
to  act  in  the  extreme  vessels  and  veins. 

In  the  first  place,  Haller,  Spallanzani, 
Thomson,  and  many  others  have  observed  in 
the  transparent  parts  of  animals  that  the  im- 
pulse of  the  heart  is  transmitted  to  the  very 
ends  of  the  small  arteries,  which  may  be  less 
than  sjgth  part  of  an  inch  in  diameter,  and  that 
in  some  states  of  the  circulation  the  impulse  of 
the  heart  is  continued  on  through  the  capillary 
vessels  and  into  the  commencements  of  the 
veins.  The  fact  that  this  generally  occurs  when 
the  action  of  the  heart  is  weakened,  and  when 
the  vessels  are  consequently  not  sufficiently 
distended  by  its  impulse  to  react  by  their 
elasticity  and  convert  the  remitting  into  a 
uniform  force,  is  a  distinct  proof  that  in  the 
natural  state  of  the  circulation  a  greater  pro- 
2x2 


668 


CIRCULATION. 


portion  of  the  force  of  the  heart  must  be  trans- 
mitted through  the  blood  to  the  capillaries, 
and  must  act  through  them  upon  the  column 
of  blood  returning  in  the  veins. 

From  the  same  experiments  it  has  appeared 
that  in  general  the  instant  any  obstruction  pre- 
vents the  action  of  the  heart  from  being  pro- 
pagated onwards  in  the  arteries,  the  progressive 
current  of  the  blood  in  the  small  vessels  be- 
comes slower  and  soon  ceases,  any  motion 
which  goes  on  afterwards  being  quite  of  a  dif- 
ferent kind  from  that  occurring  in  the  natural 
circulation. 

An  experiment  performed  by  M.  Magendie, 
and  formerly  referred  to,  also  affords  a  very 
satisfactory  proof  that  the  heart's  force  acts  in 
propelling  the  blood  through  the  whole  vascular 
system.  M.  Magendie  dissected  the  femoral 
artery  and  vein  separate  from  the  neighbouring 
parts,  and  passing  a  ligature  under  them  tight- 
ened it  round  the  whole  limb,  excepting  the 
two  principal  bloodvessels,  through  which  the 
blood  was  allowed  to  flow  freely,  lie  was  thus 
enabled  to  shew  that  the  flow  of  blood  from  an 
orifice  in  the  vein  was  immediately  dependent 
on  the  force  of  the  heart  acting  through  the 
artery,  as  it  was  suddenly  diminished  and  soon 
completely  ceased  the  instant  that  the  latter 
vessel  was  obstructed,  and  became  more  or  less 
rapid  according  as  it  was  more  or  less  com- 
pressed. We  would  further  remark  that  the 
experiments  of  Hales  and  Poiseuille,  more  par- 
ticularly the  latter,  have  shewn  that  there  is 
little  if  any  difference  in  the  force  of  the  blood 
in  arteries  of  very  different  size. 

On  the  other  hand,  it  appears  to  us  suffi- 
ciently clear  that  the  occurrence  of  any  general 
contraction  of  the  coats  of  the  arteries  would 
have  the  effect  of  opposing  an  obstacle  to  rather 
than  of  assisting  the  progress  of  the  blood  in 
the  arteries,  just  in  proportion  to  the  degree  of 
the  force  of  the  heart,  which  would  necessarily 
be  expended  in  dilating  them  to  the  required 
size,  in  order  to  allow  of  the  free  transmission 
of  the  blood  by  them;  and  as,  according  to  the 
commonly  received  opinion,  the  contractile 
powers  are  greater  in  the  smaller  than  in  the 
larger  arteries,  the  operation  of  this  contraction 
would  be  much  the  same  as  the  diminution  of 
the  aperture  through  which  blood  flows  from 
an  inorganic  tube,  and  would  thus  cause  a 
still  greater  obstruction  to  the  flow  of  blood 
than  a  general  contraction.  It  is  only  on  the 
supposition  that  the  arteries  undergo  an  undu- 
latory  or  vermicular  contraction,  proceeding 
from  the  larger  to  the  smaller  branches,  that 
this  contractile  force  can  be  believed  to  con- 
tribute to  the  progressive  motion  of  the  blood, 
because  then  it  might  be  conceived  to  assist 
the  elasticity  of  the  arterial  parietes  in  propa- 
gating the  force  of  the  heart  along  the  column 
of  contained  blood,  and  even  augment  this 
force  by  an  additional  power.  But  we  would 
remark  that  no  such  vermicular  action  has 
been  ascertained  to  occur  by  any  observations 
or  experiments  with  which  we  are  acquainted  ; 
that  in  artificial  injection  of  fluids  into  the 
large  arteries  of  dead  animals  a  force  of  a  few 
pounds  is  found  to  be  sufficient  to  propel  these 


fluids,  when  not  of  an  irritating  kind,  from  the 
arteries  into  the  veins ;  and  that  it  follows  from 
the  direct  experiments  of  many,  more  particu- 
larly those  of  Hales,  Poiseuille,  and  Magendie, 
that  the  action  of  the  heart,  transmitted  by  the 
elastic  arteries,  is  the  only  cause  operating  in 
the  progressive  propulsion  of  the  blood  in 
arteries  of  such  a  size  as  to  admit  of  the  force 
of  the  blood  being  measured  in  them. 

In  asserting,  however,  that  a  general  con- 
traction of  this  kind,  if  it  occurred  in  the  vas- 
cular system,  would  upon  the  whole  obstruct  or 
retard  rather  than  assist  the  progressive  motion 
of  the  blood  in  the  arteries,  we  would  not  be 
supposed  to  deny  that  the  vital  powers  of  the 
arteries  may  modify  very  considerably  the  dis- 
tribution of  blood  to  different  parts,  for  it  is 
manifest  that  an  increased  action  occurring  in 
one  part  of  an  artery  may  hinder  the  blood 
from  being  transmitted  in  its  usual  quantity 
into  a  neighbouring  part,  while  a  dilated  state 
of  an  artery  or  its  branches,  or,  if  we  please  to 
call  it  so,  a  diminished  action  or  greater  weak- 
ness of  resistance  of  the  coats  of  the  artery 
considered  relatively  to  the  powers  of  propul- 
sion operating  through  it,  may  occasion  the 
flow  of  a  greater  quantity  of  blood  to  a  part, 
as  occurs  in  local  inflammations.  Among  the 
many  indirect  arguments  adduced  on  both  sides 
of  this  question  may  be  mentioned  the  follow- 
ing. In  the  first  place,  the  fact  that  in  the 
lowest  classes  of  animals,  as  in  Vermes  and 
Insects,  which  have  no  proper  heart,  the  blood- 
vessels propel  the  blood  by  their  contractile 
power,  and  that  in  some  of  the  higher  animals, 
particularly  Reptiles  and  Fishes,  parts  of  the 
vascular  system,  as  the  bulb  of  the  aorta,  a 
considerable  portion  of  this  vessel,  parts  of  the 
veins,  and  so  on,  are  distinctly  contractile,  and 
assist  the  powers  of  the  heart,  are  adduced  as 
proofs  from  analogy  that  the  arteries  in  warm- 
blooded animals  may  have  the  same  power  and 
perform  the  same  function.  Now  it  may  be 
answered  to  this,  that  the  circumstance  of  the 
lowest  classes  of  animals  having  no  proper 
heart  is  the  final  cause  of  or  an  obvious  reason 
for  the  greater  contractility  of  these  vessels ; 
and  in  the  second  place,  that  no  rythmic  con- 
traction is  observed  to  occur  in  the  arteries  of 
warm-blooded  animals  of  the  same  nature  as 
that  observed  by  Haller,  Spallanzani,  M.Hall, 
and  others  in  the  bulb  of  the  aorta  and  other 
parts  of  the  vascular  system  of  cold-blooded 
Vertebrata.  For  similar  reasons  we  are  not 
inclined  to  attach  much  importance  to  the  ar- 
gument in  favour  of  the  independent  powers  of 
the  arteries  deduced  from  the  alleged  occur- 
rence of  circulation  in  acephalous  foetuses,  in 
all  of  which  the  proper  muscular  heart  seems 
to  be  wanting;  for  although  the  distribution  of 
the  vessels  in  these  foetuses  has  been  suffi- 
ciently accurately  determined,  the  nature  of 
the  circulation  which  occurs  in  them  is  a  sub- 
ject involved  in  the  greatest  obscurity.  There 
seems  good  reason  to  doubt  that  such  foetuses 
have  ever  existed  alone  in  the  uterus,  in  which 
case  their  vessels  may,  as  is  known  in  many  of 
them  to  have  occurred,  have  been  connected 
with  those  of  a  perfect  foetus;  and  even  were 


CIRCULATION. 


669 


this  not  the  case,  the  absence  of  the  heart  might 
be  attended  in  these  malformed  productions 
with  an  unusual  development  of  muscular 
power  in  parts  of  the  vascular  system.* 

In  conclusion,  we  may  remark  that  the  argu- 
ment drawn  from  the  occurrence  of  circula- 
tion apparently  little  impaired  through  arteries 
which  have  been  completely  ossified  for  a  con- 
siderable time,  seems  to  be  very  much  in  favour 
of  the  view  we  have  taken  that  the  heart  alone 
is  the  cause  of  the  progressive  flow  of  blood 
through  the  arterial  tubes. 

3.  Phenomena  of  the  capillary  circulation. — 
The  phenomena  of  the  passage  of  the  blood 
from  the  terminations  of  the  arteries  into  the 
commencement  of  the  veins  through  the  capil- 
lary vessels,  are  highly  interesting  and  impor- 
tant in  many  points  of  view,  for  the  immediate 
respiratory  change  which  the  venous  blood 
undergoes  in  the  pulmonary  vessels,  and  all 
those  alterations  of  composition  which  accom- 
pany nutrition,  growth,  secretion,  and  other 
organic  processes  connected  with  the  systemic 
vessels,  occur  in  the  smallest  ramifications  of 
the  pulmonic  and  systemic  circulation,  and  the 
morbid  state  of  inflammation  as  well  as  the 
various  pathological  changes  which  occur  as  its 
consequences  are  intimately  connected  with  an 
altered  condition  of  the  capillary  system. 

a.  Structure  and  distribution  of  the  capillary 
vessels. — The  name  of  capillary  is  generally 
given  to  all  those  minute  vessels  which  form 
the  means  of  communication  between  the 
small  ramifications  of  the  arteries  and  veins; 
but  there  is  some  difference  in  the  opinion  of 
anatomists  and  physiologists  as  to  how  much 
of  the  vascular  system  ought  to  be  included 
under  the  division  of  the  capillary  vessels. 
Some,  adhering  to  the  strict  meaning  of  the 
term,  apply  it  to  all  the  small  vessels  whatso- 
ever under  a  certain  size;  others  hold  that 
between  the  extremities  of  the  arteries  and 
veins  there  is  always  situated  a  series  of  minute 
tubes  of  nearly  equal  size  in  their  whole  length, 
and  not  ramifying  like  the  arteries  or  veins, 
which  constitute  a  system  of  vessels  distinct 
from  the  others  in  their  structure,  distribution, 
and  properties,  to  which  the  name  of  capillary 
ought  to  be  restricted  .f  The  last  view  appears 
to  us  to  be  founded  in  a  partial  acquaintance 
with  the  system  of  minute  vessels,  for  though 
it  may  be  true  that  in  some  parts  of  animals 
the  capillaries  have  obviously  the  structure 
above  described,  and  seem  to  form  a  system  of 
vessels  apart  from  the  smaller  arteries  and 
veins,  yet  this  is  by  no  means  the  case  in  other 
textures ;  and  we  think  that  the  more  extensive 
observation  of  the  structure  of  these  vessels  in 
various  parts  will  shew  that  in  the  greater 
number,  as  is  well  ascertained  to  exist  in 
many,  the  smaller  arteries  pass  into  veins 
quite  in  a  gradual  manner,  the  ramifications 
of  each  class  of  vessel  becoming  more  and 

*  See  the  Researches  of  Elben,  Tiedemann, 
Breschet,  and  others  on  Acephalous  Monsters. 

t  Dr.  Marshall  Hall's  Essay  on  the  Circulation 
of  the  Blood,  Lond.  1831.  Dr.  James  Black's 
Short  Inquiry  into  the  Capillary  Circulation,  Lond. 


more  minute  until  they  meet,  the  two  kinds 
of  vessel  presenting  no  difference  of  character 
other  than  the  change  of  direction  assumed 
by  the  moving  blood,  which  enables  us  to 
say  with  certainty  where  the  artery  termi- 
nates, and  at  what  point  the  vein  begins, 
and  affording  thus  no  reason  to  consider  the 
continuous  tube  by  which  they  join  as  different 
in  structure  from  either  the  minute  artery  or 
vein.  While  we  acknowledge  therefore  the 
importance  of  the  observations  which  point 
out  the  existence  of  capillary  vessels  of  a  uni- 
form size  in  some  textures,  we  think  it  necessary 
to  retain  the  name  of  capillary  as  applied  to  all 
the  minute  vessels,  both  for  the  reason  that  the 
communicating  vessels  are  not  every  where  of 
the  same  kind,  and  that  from  the  use  already 
made  of  the  term  by  physiological  writers  its 
meaning  will  thus  be  more  easily  understood. 

The  vessels  which  lead  from  arteries  to  veins 
are  of  very  various  sizes,  some  admitting  only 
one  globule  at  once,  others  being  so  large  as  to 
allow  of  the  passage  of  three,  four,  or  even  a 
greater  number  of  red  globules  together.  In 
tracing  with  the  microscope  the  motion  of  the 
minute  streams  of  blood  as  they  pass  through 
the  capillary  vessels,  the  eye  is  guided  by  the 

Fig.  330. 


Frog's  foot . 


670 


CIRCULATION. 


motions  of  the  red  globules  principally,  for  it 
is  very  rarely  indeed  that  the  current  of  fluid 
which  carries  the  globules  along  can  be  recog- 
nized in  the  ordinary  modes  of  observation. 

The  capillary  circulation  is  most  easily  seen 
in  cold-blooded  and  in  young  animals,  both 
on  account  of  the  large  size  of  the  red  glo- 
bules and  the  small  number  of  the  vessels. 
Since  the  first  discovery  of  the  capillary  circu- 
lation by  Malpighi,  the  transparent  web  be- 
tween the  toes  of  the  hind  feet  of  the  frog  has 
been  universally  adopted  as  the  most  con- 
venient situation  for  observing  this  beautiful 
spectacle  with  transmitted  light.  The  fins  and 
tail  of  fishes,  the  tail  of  the  larva  of  the  Frog 
and  Newt,  the  external  gills  of  the  same  ani- 
mals as  well  as  of  cartilaginous  fishes,  the 
mesentery  of  the  Frog  or  of  small  warm- 
blooded animals,  the  wing  of  the  Bat,  the 
lungs  and  urinary  bladder  of  Ileptiles,  the 
liver  of  the  Frog  and  Newt,  the  membranes 
of  the  incubated  egg,  the  yolk  of  the  Skate's 
egg,  are  all  situations  favourable  for  the  ob- 
servation of  the  capillary  circulation.  The 
capillary  circulation  has  been  viewed  in  only 
a  small  number  of  warm-blooded  animals,  and 
in  very  few  of  their  textures ;  but  the  minute 
injection  with  coloured  fluids  of  all  parts  of 
the  bodies  of  Quadrupeds  and  of  Man  leaves 
little  doubt  that  in  them  also,  whatever  vari- 
eties there  may  be  in  the  size,  number,  and 
distribution  of  the  small  vessels,  the  blood 
passes  in  every  organ  from  the  small  arteries 
into  the  returning  veins  by  minute  continuous 
tubes  of  the  same  nature  as  those  more  easily 
observed  in  the  situations  above-mentioned. 

Some  are  inclined  to  consider  the  minutest 
or  proper  capillary  vessels  as  destitute  of  vas- 
cular parietes,  and  consisting  of  mere  passages 
through  the  texture  of  the  organ  in  which  they 
exist  without  any  lining  membrane.  This 
opinion  is  founded  on  the  impossibility  of 
seeing  the  coats  of  the  vessels,  the  rapidity 
with  which  new  capillaries  may  be  developed, 
and  some  other  circumstances.  The  extreme 
degree  of  minuteness  of  the  smallest  capil- 
lary vessels  must  render  futile  any  attempts 
to  decide  this  question  by  direct  observa- 
tion. Besides  the  general  analogy  between 
the  larger  and  smaller  vessels,  there  are 
several  circumstances  known  which  seem  to  be 
strongly  in  favour  of  the  view  that  the  capil- 
laries do  not  differ  in  this  respect  from  other 
vessels.  1st,  It  is  allowable  to  suppose  that 
the  active  properties  of  the  capillary  vessels 
belong  to  parieties  as  in  the  larger  vessels. 
2d,  In  many  transparent  parts  of  animals  in 
which  the  terminal  arteries  and  veins  do  not 
diminish  to  a  very  small  size,  the  coats  of  the 
vessel  may  be  seen  with  the  microscope,  as  in 
the  external  gills  of  the  Amphibia,  and  in  the 
vascular  rete  of  the  ear  of  birds  and  reptiles, 
in  which  the  capillary  vessels  may,  after 
haying  been  injected,  be  separated  from  the 
neighbouring  soft  texture.  3d,  The  conver- 
sion of  small  into  larger  vessels  with  visible 
coats  in  those  instances  in  which  the  course 
of  blood  through  the  vessels  of  a  part  has  un- 
dergone an  alteration,  is  in  favour  of  the  pre- 


vious existence  of  parietes  in  the  smaller 
vessels.  And  4th,  The  constant  and  regular 
distribution  of  the  minutest  vessels  in  many 
parts  of  animals  appears  to  support  the  same 
view.  The  argument  in  favour  of  the  non- 
existence  of  capillary  parietes  deduced  from 
the  alleged  facility  with  which  the  blood  occa- 
sionally passes  out  of  the  regular  vessels  and 
takes  an  irregular  and  indeterminate  course 
through  the  non-vascular  parenchyma  of  an 
organ,  we  believe  to  be  founded,  in  some  in- 
stances, in  peculiarities  belonging  to  a  few  parts 
only,  and  in  others  in  inaccurate  observation; 
for  in  almost  all  those  situations  in  which  the 
capillary  circulation  may  be  seen  with  ease 
and  distinctness,  the  constancy  of  the  minute 
passages  which  the  blood  permeates  is  un- 
doubted. 

From  the  more  accurate  means  of  making 
minute  anatomical  researches  that  have  been 
introduced  in  modern  times,  the  existence  of 
serous,  exhalent,  and  white  vessels  has  become 
a  matter  of  great  doubt,  for  vessels  of  this 
description  which  do  not  admit  the  red  glo- 
bules and  liquor  sanguinis  together  cannot  be 
made  obvious  to  the  senses  by  the  most  de- 
licate injections  or  dissections ;  and  the  ob- 
servation of  the  capillary  circulation  in  the 
transparent  parts  of  animals  affords  the  most 
convincing  proof  that  the  smaller  arteries 
have  no  visible  terminations  excepting  in  the 
capillaries  and  small  veins.  In  observing 
attentively  the  web  of  the  frog's  foot  and  other 

Fig.  331. 


Capillaries  in  the  web  of  the  Frog's  foot  magnified. 

transparent  parts  in  which  the  motion  of  the 
blood  is  easily  seen,  we  occasionally  see  glo- 
bules of  blood  run  into  passages  of  the  tissue 
which  we  did  not  perceive  before  ;  but  a  suf- 
ficient acquaintance  with  the  structure  and  dis- 
tribution of  the  smallest  of  the  capillaries  in 
these  situations  will  soon  convince  the  careful 
observer  that  the  vessels  into  which  the  blood 
was  seen  to  pass,  apparently  for  the  first  time, 
existed  fully  formed  before,  that  the  fluid  part 
of  the  blood  passed  in  part  through  them,  and 
that  the  stoppage  of  the  red  particles  was  to 


CIRCULATION. 


671 


a  great  measure  dependent  on  partial  or  local 
impediments.  The  compression  of  one  of  the 
small  arteries,  for  instance,  will  frequently, 
after  causing  oscillation  of  the  globules  of  the 
blood  in  the  smallest  capillaries,  be  followed 
by  the  disappearance  of  some  of  them  ;  but 
in  a  very  short  time,  or  when  the  obstruction 
is  removed,  the  blood  regains  its  former  velo- 
city and  force,  and  flows  into  exactly  the  same 
passages  as  before. 

The  notion  that  the  smaller  vessels  are  con- 
tinuous with  the  smaller  lymphatics,  and  more 
especially  with  the  excretory  ducts  of  glands, 
seems  to  be  fully  disproved  by  the  accurate 
researches  of  Malpighi,  Mascagni,  Panizza, 
Miiller,  and  Weber,  which  have  shewn  that 
the  lymphatic  vessels  originate  at  all  parts  of 
the  body  by  a  plexus  of  tubes  every  where 
closed,  and  that  the  excretory  ducts  of  secre- 
tory organs  begin  always  by  shut  ends. 

We  believe  it  to  be  satisfactorily  shewn  that 
in  the  whitest  of  the  textures  (with  the  excep- 
tion perhaps  of  the  cornea  and  crystalline  lens), 
there  is  no  necessity  for  the  supposition  of 
vessels  admitting  the  fluid  parts  only  of  the 
blood,  or  of  serous  vessels,  as  they  have  been 
termed ;  and  that  in  all  of  them  there  exist 
small  bloodvessels  which  admit  very  fine  rows 
of  globules  in  their  accustomed  proportion  to 
the  fluid  part  of  the  blood  :  for  many  textures 
which  appear  perfectly  white  or  colourless,  or 
only  slightly  yellow  when  viewed  with  the 
naked  eye,  are  found,  when  examined  with  the 
microscope,  to  have  small  vessels  carrying  blood 
globules  through  them.  Spallanzani  and  others 
shewed  that  very  small  vessels  taken  singly  or 
seen  in  very  thin  layers  have  almost  no  per- 
ceptible colour ;  and  it  is  a  well  known  fact 
that,  in  what  are  called  the  red  textures,  the 
colour  (as  of  muscle  for  instance)  is  not  ex- 
clusively dependent  upon  the  quantity  of  red 
blood  in  them.  It  is  difficult,  indeed,  to  con- 
ceive how  the  circulation  of  the  blood  could 
be  carried  on  at  all,  or  how  the  red  particles 
of  the  blood  could  ever  be  returned  to  the 
heart  were  the  globules  to  be  retained  in  the 
larger  vessels,  and  all  the  white  textures  to 
admit  only  the  fluid  parts  of  the  blood. 

In  adopting  the  opinion  that  the  arteries 
terminate  always  by  direct  continuity  of  tube 
iu  the  veins,  and  that  no  other  visible  passages 
are  connected  with  the  minute  vessels,  we 
must  suppose  that  the  various  interchanges  of 
materials  occurring  between  the  blood  and  the 
organized  textures  or  foreign  matters,  as  in  nu- 
trition, secretion,  respiration,  transpiration,  &c. 
must  take  place  by  some  process  of  organic 
transudation  through  invisible  apertures  of  the 
minute  vessels. 

b.  Properties  of  the  capillary  vessels  and  in- 
fluence on  the  circulation. — From  the  expe- 
riments already  referred  to,  it  is  apparent  that 
the  smaller  arteries,  so  long  as  they  can  be 
distinguished  from  other  vessels,  are  capable 
of  being  excited  to  contraction  by  the  appli- 
cation of  a  stimulus ;  but  we  have  no  means 
of  shewing  this  with  regard  to  the  minutest 
capillary  vessels,  because  we  can  scarcely  apply 
any  stimulation  to  them  without  aftectin  some 


of  the  smaller  arteries  at  the  same  time.  When 
it  is  said,  for  example,  that  the  capillary  ves- 
sels are  irritable,  because  the  application  of 
ammonia  or  spirits  of  wine  causes  them  to 
become  smaller,  it  is  difficult  to  determine 
how  far  this  appearance  of  diminished  size  in 
the  capillaries  depends  on  their  receiving  less 
blood,  in  consequence  of  the  contraction  of  the 
small  arteries  leading  to  them  or  upon  the  less 
size  of  these  vessels  themselves.  In  the  expe- 
riments of  Dr.  Thomson  and  others,  however, 
the  application  of  salt  and  other  stimuli  ex- 
citing inflammation  have  appeared  to  dilate 
even  the  smallest  capillary  vessels,  and  such 
a  dilatation  can  scarcely  be  considered  as  in- 
dicating any  thing  else  than  a  less  power  of 
resistance  in  these  vessels ;  and  when  the  ap- 
plication of  ammonia  or  spirit  of  wine  restores 
such  dilated  capillaries  to  their  natural  con- 
dition, we  do  not  see  that  any  other  natural 
inference  can  be  drawn  from  this  fact  than  that 
the  capillaries  have  been  contracted  by  the 
influence  of  these  stimuli ;  for  the  contraction 
of  the  small  arteries  alone,  although  it  might 
restore  the  lost  velocity  of  the  blood,  would  not 
diminish  the  capillaries  to  their  former  size. 
This  general  diminution  of  size  ought  how- 
ever to  be  carefully  distinguished  from  the 
more  marked  and  local  contractions  of  true 
arteries. 

The  velocity  of  the  blood  is  quite  uniform 
in  the  capillaries  of  the  adult  animal  in  the 
natural  condition  of  the  circulation.  There  is 
reason  to  believe  the  capillary  vessels  to  be 
highly  elastic,  and  to  have  the  effect  of  com- 
pleting the  change  which  is  begun  by  the 
arteries,  viz.  that  of  equalizing  the  force  of  the 
heart  transmitted  through  the  blood.  We  do 
not,  in  observing  attentively  the  capillary 
vessels,  ever  perceive  any  motions  of  alter- 
nate dilatation  and  contraction  of  their  sides. 
The  blood  flows  through  them  as  through 
small  glass  tubes;  and  if  they  act  by  other 
powers  than  by  their  elasticity  alone,  this 
action  must  be  of  so  slow  a  kind  as  not  to  be 
perceptible.  There  can  be  no  doubt  that  any 
action  of  contraction  occurring  in  the  capillary 
vessels,  whether  alternating  with  dilatation  or 
not,  could  have  no  effect  excepting  that  of  ob- 
structing the  passage  of  blood  through  them. 
It  would  act  upon  the  contents  of  the  arterial 
system  much  in  the  same  way  as  the  dimi- 
nution of  the  aperture  at  the  end  of  a  rigid 
tube  would  affect  the  flow  of  fluid  through 
it,  that  is,  either  a  less  quantity  of  blood  would 
pass  through  the  capillary  vessels  in  conse- 
quence of  their  less  size,  or  a  greater  portion 
of  the  heart's  force  would  be  expended  in  di- 
lating these  vessels  to  a  sufficient  extent. 

The  principal  reasons  which  we  feel  inclined 
to  adduce  for  believing  that  the  heart's  action 
is  continued  onwards  through  the  capillaries, 
and  is  sufficient  to  return  the  blood  through 
the  veins  back  as  far  as  the  heart  itself,  are  the 
following: — 1.  That  in  an  animal  recently 
killed  a  very  small  force  only  is  requisite  to 
cause  bland  fluids  to  follow  the  course  of  the 
blood,  provided  the  injection  be  made  before 
the  tonic  contraction  has  had  time  to  constrict 


672 


CIRCULATION. 


the  vessels.  2.  The  experiments  of  Hales  and 
Wedemeyer  shewing  that,  according  to  the 
more  or  less  stimulating  character  of  the  fluids, 
their  passage  through  the  vessels  was  more  or 
less  easy.  3.  The  experiments  shewing  that, 
in  an  animal  which  has  been  dead  for  some 
time,  steeping  of  the  body  in  warm  water,  and 
the  injection  of  warm  water  into  the  vessels, 
so  as  to  clear  the  passage  through  them,  puts 
the  vessels  in  such  a  condition  that  a  force  of  a 
few  pounds  is  sufficient  to  effect  the  pro- 
pulsion of  fluids  through  them.  4.  The  ob- 
servations of  Haller,  Spallanzani,  Magendie, 
and  others,  that  all  regular  progressive  motion 
of  blood  in  a  vein,  or  the  issue  of  blood  from 
an  orifice  in  a  vein,  ceases  very  soon  after 
the  heart's  action  is  suspended,  or  when  any 
obstacle  prevents  its  force  being  communicated 
to  the  blood  in  the  veins.  5.  The  observations 
of  Spallanzani,  Thomson,  and  others,  that  the 
impulses  of  the  heart  are  visibly  continued  on 
through  the  small  arteries  and  capillaries,  and 
even  into  the  veins  in  some  states  of  the  circu- 
lation. This  phenomenon  is  most  apparent  at 
the  time  when  the  action  of  the  heart  is  weak, 
and  in  such  states  of  the  circulation  this  re- 
mittent flow  of  the  blood  may  be  converted 
into  a  merely  oscillatory  movement  without 
any  regular  progression  by  the  gradual  increase 
of  the  pressure  applied  to  the  artery  which 
supplies  the  blood  to  the  capillary  vessels 
under  observation;  a  fact  which  shews  dis- 
tinctly on  the  one  hand  that  the  force  of  the 
heart  is  continued  on  through  the  capillaries, 
and  on  the  other  that  when  a  resistance  is  op- 
posed to  the  progress  of  the  action  of  the 
heart  through  the  arteries,  no  other  force  then 
operates  sufficient  to  cause  a  continued  and 
piogressive  motion  of  the  blood. 

But,  although  the  small  vessels  do  not  con- 
tribute by  their  active  contraction  to  propel  the 
blood  through  them,  or  although  they  do  not 
as  a  whole  assist  the  force  of  the  heart,  it  is 
yet  very  apparent  that  they  have  the  power  of 
modifying  in  a  remarkable  manner  the  flow  of 
blood  in  particular  parts.  Among  the  circum- 
stances which  prove  this  power  of  the  small 
vessels  to  modify  the  circulation  may  be  men- 
tioned the  various  instances  in  which  there 
occur  local  determinations  to  particular  parts, 
unaccompanied  by  any  change  in  the  action  of 
the  heart  or  in  the  general  circulation.  1 .  The 
act  of  blushing  and  erection,  or  the  reverse 
actions  of  paleness,  collapse,  &c.  which  seem 
to  depend,  in  most  instances  at  least,  on  some 
change  in  the  terminal  vessels  2.  Inflam- 
mations or  hemorrhages  confined  to  a  parti- 
cular part  of  the  body.  3.  The  increase  or 
decrease  of  secretions  from  glands,  periodical 
or  instantaneous.  4.  The  increased  size  of 
the  vessels  of  the  uterus  during  pregnancy, 
of  the  mammae  after  child-birth,  &c.  5.  The 
enlargement  of  bloodvessels  in  new  growths, 
tumours,  &c.  6.  The  enlargement  of  collateral 
anastomosing  vessels,  after  the  closure  of  the 
principal  trunk  of  a  limb.  And,  7.  The  unequal 
growth  or  development  of  different  parts  of  the 
foetus.  Although  we  do  not  understand  the 
nature  of  the  change  in  the  vessels  which 


accompanies  these  partial  distributions  of 
blood  to  particular  parts,  yet  they  all  suffi- 
ciently demonstrate  that  while  the  heart's  action 
remains  the  same,  the  quantity  of  blood  sent  to 
particular  parts  must  have  been  modified  by 
some  action  of  the  vessels  themselves. 

There  are  some  physiologists,  however,  who 
hold  the  opinion  that  the  motion  of  the  blood 
is  promoted  in  some  way  or  other  (they  do  not 
sufficiently  clearly  explain  how)  by  powers 
acting  on  it  during  its  passage  through  the 
capillary  vessels;  and  there  are  a  few  who 
have  gone  so  far  as  to  suppose  that  the 
heart  drives  the  blood  only  as  far  as  the  capil- 
laries, from  whence  it  is  propelled  onwards 
into  the  veins  by  powers  originating  in  the 
small  vessels  themselves.  These  opinions  have 
been  supported  chiefly  by  arguments  drawn 
from  the  facts  already  mentioned  as  illustrating 
the  power  of  the  small  vessels  to  modify  the 
circulation  or  to  cause  local  variations  in  the 
distribution  of  the  blood,  as  also  on  the  fol- 
lowing grounds,  which  are  ably  stated  in  a 
supplement  to  his  Outlines  of  Physiology,* 
recently  published  by  Professor  Alison,  of 
Edinburgh,  who  is  one  of  those  who  have 
more  lately  adopted  this  opinion,  and  by  Dr. 
Black  in  an  ingenious  essay  on  the  capillary 
circulation  ,f 

Besides  the  analogical  argument  drawn  from 
the  lower  animals  having  a  circulation  of  fluids 
without  any  heart,  and  the  supposed  unaided 
circulation  in  acardiac  foetuses,  it  is  stated 
that — 

1.  After  the  heart  of  the  frog  or  such  cold- 
blooded animals  has  been  cut  out,  or  a  liga- 
ture passed  round  the  aorta,  some  motion  of 
the  blood  still  continues  to  occur  for  a  few 
minutes  in  the  small  vessels  ;  and  it  is  farther 
stated,  that  this  motion  is  influenced  by  heat, 
by  certain  applications  to  the  web  of  the  frog's 
foot,  and  the  state  of  the  nervous  system.}: 

2.  That  while    the  circulation  is  going  on 
with  its  usual  freedom,  the  direction  and  velo- 
city of  the  flow  of  blood  are  subject  to  sud- 
den or  rapid  changes  which  do  not  admit  of 
being  accounted  for  simply  by  contractions  of 
the  vessels. 

3.  That  the  blood  when  out  of  the  vessels, 
immediately  after  it  has  been  drawn,  or  when 
extra  vasated  in  the  textures,  performs  motions 
which  seem    to  belong  to  itself  or  are  spon- 
taneous.§ 

4.  That  the  passage   of  the  blood  through 
the  capillary  vessels   of  the   lungs   is  imme- 
diately influenced   by  the  chemical  change  of 
the  venous  blood  into  arterial,  for  its  velocity 
is  diminished  as  soon  as  this  change  does  not 
occur.|| 

5.  That  the  remoteness  of  the  capillaries  of 
the  vena  portae  of  the  liver  from  the  heart  ren- 

*  Outlines  of  Physiology,  Supplement  to  2d 
edit.  Edin.  1836. 

t  London,  1825. 

%  Haller,  Guillot,  Leuret  and  Wilson  Philip, 
Marshall  Hall,  and  others. 

§  Kielmeyer,  Treviranus;  Carus,  Czermack, 
GEsterreicher,  and  Schultz. 

H  Dr.  Alison,  loc.  cit. 


CIRCULATION. 


673 


ders  probable  the  existence  in  them  of  some 
power  capable  of  propelling  the  blood  inde- 
pendently of  the  heart's  action. 

6.  That  in  the  production  of  new  vessels 
which  occurs  in  adhesion  or  granulation,  the 
new  blood  executes  oscillatory  motions  in  the 
rudimentary  vessels  while  in  the  act  of  form- 
ing, before  these  parts  of  vessels  are  connected 
with  the  previously  existing  branches  through 
which  the  heart  propels  the  blood  ;  and  this  is 
said  also  to  occur  in  the  formation  of  new  ves- 
sels in  natural  growth.* 

7.  That  in   the   formation   of  the  vascular 
area  of  the  incubated  egg  the  blood  moves  in 
part  through  the  veins  and  small  vessels  before 
it  is  impelled  by  the  action  of  the  heart.f 

We  would  remark,  regarding  the  oscillatory 
and  irregular  motions  described  by  Haller  and 
others  as  occurring  in  the  small  vessels  of  the 
web  after  removal  of  the  heart  or  ligature  of 
the  aorta,  that  we  believe  some  of  these  to  be 
caused  by  the  elasticity  of  both  the  arteries 
and  veins,  and  others  to  be  occasioned  by  the 
gradual  or  tonic  contractions  which  take  place 
in  the  arteries  after  death  :|  they  occurred  in  all 
Haller's  observations,  but  in  Spallanzani's  only 
when  the  apparatus  of  hooks  constantly  em- 
ployed by  Haller  was  applied ;  and  so  far  as  we 
have  ourselves  been  able  to  observe  them,  we 
have  always  found  them  influenced  by  very  slight 
changes.  When  one  of  the  small  vessels  is 
obstructed  they  cease  altogether,  which  ought 
not  to  be  the  case  were  they  dependent  upon 
powers  belonging  to  the  capillaries  or  the  blood 
in  them.  Some  varieties  in  the  velocity  and  di- 
rection of  the  blood  in  the  smaller  vessels  we 
have  reason,  from  our  own  observations,  to 
attribute  to  the  same  causes,  and  we  think  it 
consonant  with  such  a  supposition  that  heat  or 
other  agents  influencing  the  contraction  of 
arteries  should  influence  these  irregular  mo- 
tions. The  oscillations  of  blood  in  parts  of 
vessels  which  are  in  the  process  of  formation 
in  adhesions  and  granulations,  or  in  natural 
growth,  we  have  not  yet  been  able  to  observe  so 
clearly  as  to  be  certain  that  we  were  not  de- 
ceived ;  but,  even  supposing  them  to  have 
been  satisfactorily  proved  to  occur,  we  should 
be  inclined  to  doubt  the  possibility  of  ascer- 
taining with  accuracy  that  these  portions  of 
vessel  are  entirely  shut  off  from  all  commu- 
nication with  other  vessels,  so  as  that  no  im- 
pulse could  be  transmitted  from  the  heart  to 
them.  The  necessity  of  some  change  in  the 
tissue  of  organs  or  of  organizable  lymph,  in 
which  new  vessels  are  about  to  be  formed 
before  the  propulsion  of  the  blood  into  the 
new  loop  of  vessel  seems  sufficiently  obvious, 

*  Boellinger,  Journ.  des  Progres,  &c.  vol.  ix. 
Kaltenbrunner,  loc.  cit.  Baumg'a'rtner,  Beobacht. 
iiber  die  Nerven  und  das  Blut.  Freiburg.  1830. 

t  [Dr.  Tanchose  suggests  as  a  cause  for  the  mo- 
tion of  the  blood  in  the  capillaries,  the  ceaseless 
removal  of  particles  from  the  blood  to  supply  ma- 
terials to  the  various  secretions,  &c.  a  constant 
tendency  to  a  vacuum  being  thereby  produced. 
Acad.  des  Sciences,  Seances  d'Avril,  1833. — ED.] 

$  See  Marshall  Hall's  Essay,  p.  95;  and  also 
Black's  Inquiry,  for  judicious  remarks  upon  these 
oscillations. 


but  it  does  not  appear  to  be  as  yet  satisfactorily 
shewn  that  the  motion  of  blood  in  the  new 
vessels  is  independent  of  a  propulsion  received 
from  the  heart.  Again  we  consider  it  as  ascer- 
tained that  the  heart  of  the  chick  acts  just  as 
soon  as  any  motion  of  fluids  can  be  seen  on 
the  vascular  area  of  the  yolk ;  and  though  it 
may  be  admitted  that  a  certain  change  of  place 
in  the  particles  of  the  yolk  is  necessary  in  the 
new  combinations  which  occur  during  the  de- 
velopmentof  the  forming  parts  from  its  substance, 
yet  such  a  change  or  motion  must  be  quite  of 
an  insensible  kind  and  not  in  any  degree  ana- 
logous to  the  continued  stream  of  circulating 
blood  through  the  vessels. 

The  stagnation  of  venous  blood  in  the  capil- 
laries of  the  lungs  is  certainly  a  most  remark- 
able and  inexplicable  phenomenon,  but  if  from 
analogy  any  weight  is  to  be  attached  to  obser- 
vations made  upon  the  frog,  it  may  be  stated 
that  the  flow  of  blood  through  the  lungs  seems 
as  immediately  dependent  on  the  heart's  action 
as  that  through  the  system.  The  portal  circu- 
lation is  not  more  remarkable  in  respect  of  its 
isolation  from  the  heart  than  the  systemic  cir- 
culation of  fishes,  in  which  animals  the  capil- 
laries of  the  gills  intervene  between  the  heart 
and  the  systemic  aorta;  and  without  any  dis- 
tinct contraction  of  that  vessel,  the  circulation 
of  the  blood  in  the  systemic  capillaries  as 
well  as  in  the  gills  is  very  manifestly  main- 
tained chiefly,  if  not  solely,  by  the  action  of 
the  heart.  We  do  not  feel  inclined  to  attach 
any  importance  to  the  alleged  motions  of  the 
globules  of  the  blood  out  of  the  vessels,  for 
we  have  never  been  able  to  see  any  such  in- 
dicating different  powers  from  those  which 
produce  currents  in  inorganic  fluids,  and  some 
of  the  observations  upon  which  the  statement 
is  founded  have  been  shewn  to  be  erroneous. 

We  think  it  unnecessary  to  do  more  than 
merely  to  allude  to  some  of  the  very  many 
attempts  that  have  been  made  to  account  for 
independent  motion  of  blood  in  the  capillaries, 
or  what  have  been  termed  the  theories  of  the 
capillary  circulation. 

All  that  we  know  of  capillary  attraction  mi- 
litates against  the  possibility  of  its  being  the 
means  of  causing  a  progressive  motion  of  fluids, 
such  as  that  which  occurs  in  plants  and  ani- 
mals. Those  who  have  attributed  the  motions 
of  fluids  in  the  living  body  to  endosmosis  or  a 
principle  of  organic  transudation,  have  failed 
in  pointing  out  in  the  bloodvessels  the  condi- 
tions necessary  for  the  occurrence  of  a  motion 
proceeding  from  an  action  of  this  description. 
The  electrical  theory  is  defective  in  this  essen- 
tial point,  that  no  difference  in  the  electrical 
condition  of  the  arterial  and  venous  blood  has 
been  shewn,  and  that  the  same  cause  to  which 
the  motion  of  the  capillaries  of  the  systemic 
arteries  is  ascribed  ought  to  retard  the  passage 
of  blood  in  the  pulmonary  capillaries,  the  re- 
lations of  the  two  kinds  of  blood  being  there 
reversed.  The  opinion  that  the  motion  of  the 
blood  in  the  vessels  is  analogous  to  those  cur- 
rents of  fluids  which  take  place  in  contact  with 
the  surfaces  of  various  parts  of  animals,  which 
are  almost  always  connected  with  ciliary  mo- 


674 


CIRCULATION. 


lions,  and  are  described  under  the  head  of 
CILIA  in  this  Cyclopaedia,  isdefective  in  so 
far  as  neither  cilia  nor  any  power  of  exciting 
currents  has  yet  been  shewn  to  exist  in  the 
interior  of  the  bloodvessels,  and  they  have 
been  examined  in  circumstances  in  which  we 
conceive  they  would  have  been  seen  had  they 
been  present.  In  fine  we  cannot  see  how  any 
power  of  spontaneous  motion  belonging  to  the 
blood  itself  could  be  a  cause  of  progressive 
motion  of  that  fluid,  unless  the  direction  of  the 
motion  were  determined  by  the  solid  textures 
containing  the  blood,  and  in  this  case  the  same 
objections  would  apply  to  this  explanation  of 
the  cause  of  motion  as  to  the  one  to  which  allu- 
sion has  just  been  made;  and  besides,  the  evi- 
dence of  spontaneous  motions  of  the  blood  ap- 
pears upon  the  whole  of  a  very  unsatisfactory 
kind. 

From  these  considerations  we  find  ourselves 
constrained  to  hold  the  opinion  that,  however 
great  the  power  which  the  capillary  vessels 
possess  of  modifying  the  distribution  of  the 
blood,  there  is  not  reason  to  believe  that  they 
contribute  as  a  whole  to  its  progressive  motion. 

4.  Phenomena  of  the  venom  circulation. — In 
the  natural  state  of  the  circulation  the  flow  of 
the  blood  is  nearly  quite  uniform  in  the  veins, 
as  may  be  seen  when  a  vein  is  opened  in  the 
common  operation  of  venesection.  In  those 
rare  instances  in  which  the  flow  from  a  vein  is 
accelerated  after  each  beat  of  the  heart,  in  the 
same  way  as  the  arterial  jet,  it  may  be  supposed 
either  that  the  intermitting  impulses  of  the 
heart  are,  from  some  circumstance  or  other, 
transmitted  more  freely  and  to  a  greater  dis- 
tance than  usual  through  the  capillary  vessels, 
as  is  known  occasionally  to  happen,  or,  what  is 
more  probable,  that  the  larger  branch  of  the 
vein  receives  the  successive  impulses  directly 
from  neighbouring  large  arteries,  which  are 
more  than  usually  dilatable. 

As  the  size  of  the  veins  is  generally  greater 
than  that  of  the  corresponding  arteries  at  the 
same  distance  from  the  heart,  and  as  they  are 
also  more  numerous,  the  velocity  of  blood  is 
less  in  these  parts  of  the  veins  than  of  the  arte- 
ries ;  and  as  the  whole  venous  system  contains 
considerably  more  blood  than  the  arterial,  the 
velocity  of  the  blood  taken  as  a  whole  must  be 
less  in  the  veins  than  in  the  arteries.  The  same 
quantity  of  blood  must  be  brought  by  the  venae 
cavae  to  the  right  auricle  as  issues  from  the  left 
ventricle,  (making  allowance  for  the  expendi- 
ture by  secretions,  &c.)  and  consequently  the 
velocity  of  the  blood  entering  and  of  that  issuing 
from  the  heart  must  be  equal.  Again,  the  ve- 
locity of  the  blood  must  be  gradually  on  the 
increase  in  its  progress  from  the  small  to  the 
larger  veins,  because  the  capacity  of  the  vessels 
into  which  it  flows  is  gradually  becoming  less. 

In  the  systemic  veins,  excepting  the  venae 
portae,  the  direction  of  the  flow  of  blood  is  de- 
termined by  the  structure  of  the  valves,  which 
permit  of  the  return  of  blood  from  the  extremi- 
ties of  the  veins  towards  the  heart,  but  oppose, 
by  the  filling  of  their  pouches  and  the  apposi- 
tion of  their  free  edges,  a  complete  obstacle  to 
the  reflux  of  the  blood  in  another  direction. 


The  principal  cause  of  the  progressive  flow 
of  the  blood  in  the  veins  is  unquestionably  the 
force  of  impulsion  of  the  heart  continued 
through  the  arteries  and  small  vessels,  as  ap- 
pears from  the  flow  from  the  remote  part  of  an 
opened  vein  and  the  simple  experiments  of 
Hales,  Magendie,  and  Poiseuille  already  re- 
ferred to.  Hales  ascertained,  by  introducing 
tubes  into  the  larger  veins  of  the  horse,  that  the 
pressure  on  the  blood  from  behind,  or  vis  a  tergo, 
is  sufficient  to  raise  the  blood  in  the  tube  to  a 
considerable  height  above  the  level  of  the  heart, 
and  is  consequently  more  than  sufficient  to  re- 
turn the  blood  to  the  auricle  of  the  heart.  The 
blood  did  not,  in  Hales'  experiments,  in  ge- 
neral at  first  rise  in  the  tube  connected  with 
a  vein  more  than  six  inches,  but  this  he 
shewed  to  proceed  from  the  easy  escape  of 
the  blood  by  lateral  communicating  vessels, 
for  when  the  other  large  veins  were  tied,  or 
when  they  became  fully  distended  with  blood, 
that  fluid  sometimes  rose  in  the  tube  connected 
with  a  large  vein  to  a  height  of  three  or  four 
feet.  M.  Poiseuille*  demonstrated,  in  a  still 
more  satisfactory  manner,  the  action  of  the 
pressure  of  the  heart  on  the  blood  in  the  veins 
by  means  of  the  bent  tube  with  which  he  mea- 
sured the  pressure  of  the  arterial  blood  :  and 
this  fact  is  proved  in  an  equally  convincing 
manner  by  Magendie's  experiment  of  isolating 
the  principal  artery  and  vein  from  the  other 
parts  of  the  limb  of  an  animal,  in  which  it  was 
found  that  the  flow  of  blood  from  the  vein  is 
immediately  stopped  by  pressure  or  ligature  of 
the  artery.  It  is  scarcely  necessary,  in  order  to 
obtain  a  proof  of  this  fact,  to  have  recourse 
to  the  vivisection  of  animals,  for  in  common 
bleeding  from  the  arm,  the  flow  of  blood  from 
the  vein  will  be  found  to  be  immediately  influ- 
enced by  the  state  of  the  artery,  and  even  with- 
out the  division  of  a  vein,  it  is  easy  to  observe 
the  action  of  this  force  of  impulsion  which 
drives  the  blood  onwards  towards  the  heart  in 
any  of  the  superficial  veins  of  the  arm  by  the 
application  of  external  pressure,  a  mode  of 
illustration  successfully  adopted  by  Harvey  in 
his  explanation  of  the  course  of  the  blood. 
These  very  simple  experiments  are  looked  upon 
by  some  as  quite  sufficient  to  demonstrate  the 
proposition  that  the  blood  is  moved  in  the 
veins  by  an  impulsion  from  behind,  and  that 
that  impulsion  is  derived  from  the  action  of  the 
heart;  while  others,  not  satisfied  with  this  ex- 
planation, have  endeavoured  to  point  out  addi- 
tional forces  as  contributing  to  the  progressive 
motion  of  the  blood  in  the  veins. 

The  larger  veins  are,  like  the  arteries,  highly 
elastic,  and  they  are  generally  regarded  as 
stronger  proportionally  to  the  thickness  of  their 
coats  than  the  arteries.  This  elasticity  belongs 
chiefly  to  the  external  cellular  coat,  for  a  mid- 
dle fibrous  coat  is  not  apparent  in  most  of  the 
larger  healthy  veins,  and  in  those  rarer  in- 
stances in  which  it  is  apparent,  it  is  very 
much  thinner  than  in  the  arteries.  The  smaller 
or  capillary  veins  appear  also  to  be  possessed 
of  some  degree  of  irritability,  for  they  have  been 

*  Magendie's  Journ.  vol.  x. 


CIRCULATION. 


C75 


seen  to  contract  on  the  application  of  a  stimu- 
lus in  the  web  of  the  frog's  foot  by  Drs.  Thom- 
son and  Hastings.  This,  however,  occurs 
much  more  rarely  than  the  contraction  of  the 
small  arteries.  It  has  been  remarked  that  in 
some  animals  muscular  fibres  are  prolonged 
from  the  auricle  upon  the  adjoining  part  of  the 
vena  cava;  and  Spallanzani,  M.Ilall,Flourens,* 
and  others  have  recorded  the  fact  of  the  rythmic 
contraction  of  parts  of  the  great  veins  adjoining 
the  auricles.  But,  excepting  in  these  situations 
and  in  the  caudal  heart,  observed  by  M.  Hall 
in  the  Eel,  muscularity  of  the  veins  cannot  be 
considered  as  having  any  effect  in  promoting 
the  flow  of  the  blood  in  these  vessels. 

The  progressive  motion  of  the  venous  blood 
takes  place  with  little  force,  and  is  therefore 
subject  to  considerable  variations  from  external 
pressure.  Thus  the  flow  of  the  blood  may  be 
much  accelerated  by  raising  a  limb,  or  retarded 
by  keeping  it  in  the  depending  posture  from 
the  mere  effect  of  gravitation,  and  the  common 
practice  of  making  a  person  who  is  bled  in  the 
arm  call  the  muscles  of  the  arm  into  action 
during  the  operation,  is  a  sufficient  proof  that 
the  pressure  of  the  muscles  may  be  the  means 
of  accelerating  in  a  considerable  degree  the 
venous  circulation, — an  effect  obviously  depen- 
dent on  the  disposition  of  the  valves.  Gravita- 
tion or  muscular  action  are,  however,  only  occa- 
sional causes  of  the  acceleration  of  the  flow  of 
blood  in  the  veins,  and  both,  but  particularly 
gravitation,  may  in  some  instances  offer  an  ob- 
stacle to  its  progress. 

There  are  some  physiologists  who  believe 
the  blood  to  be  drawn  through  the  veins  to- 
wards the  heart  by  a  power  of  suction  which 
operates  from  the  side  of  the  heart  or  chest. 
The  remarks  we  have  already  made  in  treating 
of  the  arterial  and  capillary  circulations  render 
it  unnecessary  for  us  to  revert  in  this  place  to 
the  arguments  employed  by  those  who  have 
supported  the  above  view,  merely  on  account 
of  their  belief  in  the  inadequacy  of  the  heart's 
force  to  maintain  the  complete  circulation  ;  we 
shall  only  now  state  the  direct  experiments  or 
reasonings  by  which  it  has  been  attempted  to 
be  proved  that  a  vis  dfronte  or  suction  power 
draws  the  blood  towards  the  centre  of  the  cir- 
culation. We  have  already,  in  a  former  part 
of  this  article,  stated  our  reasons  for  believing 
that  the  elastic  power  of  the  heart  itself  is  not 
attended  with  any  production  of  an  appreciable 
force  sufficient  to  draw  the  blood  into  its  inte- 
rior. 

The  facts  which  relate  to  the  supposition 
that  the  chest  or  lungs  become,  during  their 
motions  in  respiration,  the  source  of  a  suction 
power  which  acts  on  the  venous  blood  may  be 
suitably  considered  under  the  first  part  of  the 
fourth  division  of  this  article,  viz. 

IV.      TllE     RELATION     OF    THE     CIRCULATION 
TO    OTHER    FUNCTIONS. 

1.  Respiration. — Of  the  opinions  of  those 
who  attribute  the  suction  of  the  blood  through 
the  veins  to  powers  within  the  chest,  there 

*  Annales  des  Sciences  Natur.  torn,  xxviii.  p.  65. 


are  chiefly  two  which  have  of  late  years  at- 
tracted attention, — those  namely  of  Dr.  Car- 
son of  Liverpool,*  and  of  the  late  Sir  David 
Barry  .f 

According  to  Dr.  Carson  the  lungs  are  of  a 
highly  elastic  nature,  and  are  kept  in  a  state  of 
forced  distension  by  the  pressure  of  the  atmo- 
sphere which  enters  them  when  the  chest  dilates. 
The  lungs  would  collapse  or  fall  away  from  the 
walls  of  the  chest  but  for  the  force  with  which 
they  are  distended,  and  there  is  thus  a  tendency 
to  the  production  of  a  vacuum  within  the  chest 
or  to  a  diminution  of  the  pressure  on  the  exte- 
rior of  the  heart,  in  consequence  of  which  the 
blood  is  forced  or  drawn  into  the  heart  and 
chest  on  the  same  principle  that  fluid  enters 
the  mouth  in  the  act  of  sucking. 

According  to  Sir  D.  Barry,  at  each  inspira- 
tion of  air  into  the  chest  the  lungs  are  not  suffi- 
ciently expanded  to  fill  the  whole  of  the  chest, 
or  there  is,  in  consequence  of  the  expansion  of 
the  walls  of  the  chest,  a  less  pressure  within  the 
chest  than  on  its  exterior,  and  the  blood  is  pro- 
pelled through  the  veins  communicating  with 
the  heart  by  the  external  atmospheric  pressure. 

Neither  Dr.  Carson  nor  Sir  D.  Barry  state, 
in  a  sufficiently  explicit  manner,  how  much  of 
the  force  impelling  the  blood  through  the  veins 
they  conceive  to  be  of  the  nature  of  suction : 
they  both  admit  that  the  greatest  part  of  this 
force  belongs  to  the  heart  or  vis  a  tergo,  but 
they  yet  state  distinctly  their  belief  that  the 
suction  power  is  an  important  cause  of  the  mo- 
tion of  the  blood  throughout  the  whole  venous 
system .  The  works  of  both  these  authors  are 
replete  with  interesting  remarks  on  the  circula- 
tion in  general,  and  more  especially  on  the  flow 
of  blood  through  the  veins.  The  direct  expe- 
riments, however,  in  support  of  their  opinions 
are  comparatively  few  and  inconclusive.  Dr. 
Carson  shewed  that  the  lungs  are  always  during 
life  in  a  state  of  forced  expansion,  and  estimates 
the  pressure  which  the  lungs  of  the  sheep  are 
capable  of  sustaining,  when  in  the  expanded 
condition,  as  equal  to  a  column  of  seven 
inches  of  water.  Sir  D.  Barry  observed,  in 
experiments  made  upon  horses,  that  when 
one  end  of  a  tube  is  introduced  into  the  ju- 
gular vein,  and  the  other  extremity  rests  in  a 
vessel  containing  water,  the  water  rose  during 
each  inspiration  some  length  in  the  tube,  and 
sank  again  during  expiration,  distinctly  indi- 
cating the  diminished  pressure  existing  within 
the  chest  at  the  time  of  the  rise  of  the  water, 
and  proving  that  the  flow  of  the  blood  in  some 
parts  of  the  veins  may  be  accelerated  during 
inspiration  from  the  same  cause.  Poiseuille,J 
by  the  employment  of  the  instrument  for  mea- 
suring the  pressure  of  the  animal  fluids,  to  which 
allusion  has  already  frequently  been  made,  has 
confirmed  Sir  D.  Barry's  statement,  that  the  di- 
minished pressure  within  the  chest,  at  the  time 
of  inspiration,  is  such  as  to  affect  the  flow  of 

*  Inquiry  into  the  Causes  of  the  Motion  of  the 
Blood,  &c.  Liverpool,  1815. 

t  Experimental  Researches  on  the  Influence  of 
Atmospheric  Pressure  upon  the  Progression  of  the 
Blood  in  the  Veins,  &c.  Lond.  1826. 

{  Loc.  citajt. 


676 


CIRCULATION. 


blood  in  the  jugular  vein,  and  to  draw  it  in 
some  degree  towards  the  heart.  In  many  persons, 
particularly  the  young  and  those  of  a  thin  habit 
of  body,  the  jugular  veins  in  the  neck  are  fre- 
quently very  distinctly  seen  to  become  full 
during  expiration,  and  to  be  rapidly  emptied 
and  collapsed  during  inspiration, — a  fact  which 
shews  clearly  enough  that  the  blood  passing 
through  this  vein  enters  the  chest  most  easily 
when  that  cavity  is  dilated.  The  position, 
however,  of  the  body  has  a  very  considerable 
influence  on  this  rapid  evacuation  of  the  jugular 
veins  in  such  instances.  Again,  there  are 
several  direct  experiments  upon  animals  which 
are  much  opposed  to  the  views  at  present  un- 
der consideration. 

Dr.  Arnott*  has  shewn  very  successfully  that 
such  a  power  as  that  supposed  to  aid  the  venous 
circulation  could  have  very  little  effect  in  pro- 
moting the  flow  of  fluids  through  soft  tubes, 
which  collapse  as  easily  as  the  larger  veins  do, 
because  not  more  than  an  inch  of  fluid  at  the 
most  can  be  drawn  through  one  of  them  by  a 
syringe,  without  its  sides  being  brought  toge- 
ther so  as  to  close  the  mouth  of  the  syringe, 
and  this  objection  is  in  no  way  removed  by  the 
circumstance  that  the  veins  are  kept  open  by 
the  vis  a  tergo  of  the  heart,  because  even  al- 
though they  should  be  open,  a.  force  from  be- 
fore, to  adopt  the  incorrect  expression  frequently 
applied  to  a  suction  power,  if  strong  enough  to 
make  any  impression  on  the  flow  of  the  blood, 
would  act,  to  a  certain  amount,  just  in  the 
same  way  as  if  no  force  from  behind  existed ; 
that  is,  it  would  tend  to  make  the  sides  of  the 
vessel  come  together,  and  would  thus  offer  an 
obstacle  to  the  further  progress  of  the  blood. 

In  repeating  some  of  Barry's  experiments, 
Mr.  Ellerbyf  found  that  when  he  introduced 
a  tube  into  the  jugular  vein  of  an  ass  for  two 
or  three  inches  only,  there  was  no  suction  ex- 
erted through  it,  but  that  the  fluid  in  which  its 
further  extremity  was  immersed  rose  only  when 
the  tube  was  thrust  eight  or  nine  inches  into 
the  vein  so  as  to  reach  the  chest,  in  which  case, 
of  course,  the  vein  was  held  open  by  the  rigid 
tube,  and  the  suction  power  was  enabled  to  act 
through  it  to  an  extent  which  does  not  take 
place  in  the  natural  state  of  the  jugular  vein. 
Messrs.  Ellerby  and  DaviesJ  also  found  that 
the  venous  circulation  was  for  a  short  time  not 
materially  impeded  by  opening  the  chest  or 
the  introduction  of  tubes  into  it  through  the 
parietes.  It  must  be  apparent  to  every  one  that 
the  suction  power  or  vis  a  f  route  can  exert  lit- 
tle, if  any,  force  of  traction  on  the  blood  in  the 
large  or  superficial  veins  of  the  limbs,  for  on 
making  pressure  upon  the  trunks  of  one  of 
these,  so  as  to  prevent  the  action  of  the  vis  d 
tergo,  we  find  that  if  the  limb  is  at  rest  the 
motion  of  the  blood  in  the  part  next  the  heart 
is  wholly  arrested.  But  if,  while  we  maintain 
the  pressure  on  the  vein  at  one  place  we  empty 
the  vein  for  some  way  towards  the  heart, 
close  the  vein  on  the  side  next  the  heart,  and 
then  remove  the  pressure  from  the  remote 

*  Elements  of  Physics,  vol.  i. 
t  Lancet,  vol.  xi.  p.  326. 
J  Lancet,  vol.  xi.  606. 


situation,  the  blood  is  at  once  impelled  through 
the  portion  of  the  vein  which  had  been  emptied, 
by  the  force  of  the  heart  alone.  Messrs.  Ellerby 
and  Davies  have  shewn  that  the  same  pheno- 
mena, or  the  absence  of  a  vis  afronte  and  evi- 
dence of  a  vis  d  tergo,  attend  the  flow  of  blood 
in  the  largest  veins  even,  which  are  situated  in 
the  immediate  neighbourhood  of  the  chest ;  for 
after  the  application  of  a  ligature  upon  the  vena 
cava  inferior,  it  was  found  that  the  part  of  this 
vein  between  the  ligature  and  the  chest  was  not 
emptied  towards  the  heart,  and  that  when  the 
part  of  the  vena  cava  in  the  immediate  vicinity 
of  the  chest  was  emptied,  and  pressure  then 
applied  at  the  entrance  of  the  vena  cava  into 
the  auricle,  the  blood  rose  to  fill  the  emptied 
portion  of  the  vena  cava,  although  no  suction 
power  could  in  this  place  operate.  It  was  also 
found  that  no  fluid  rose  in  the  remote  extremity 
of  a  tube  introduced  into  the  femoral  vein.* 
These  experiments  shew  that  a  suction  power, 
whether  produced  in  the  way  supposed  by  Dr. 
Carson,  or  in  that  stated  by  Sir  D.  Barry,  can 
have  very  little  effect  in  promoting  the  flow 
of  blood  in  the  veins, — a  conclusion  which  is 
rendered  still  more  certain  from  some  other  ge- 
neral considerations,  such  as  the  following  : 

1 .  The  whole  of  the  vessels  belonging  to  the 
pulmonary  circulation   are  placed  within  the 
chest,  and  consequently  the  flow  of  blood  in 
the  pulmonary  veins  must  be  independent  of 
any  suction  power  connected  with  respiration .f 

2.  In  the  foetus,  as  there  is  no  pulmonary 
respiration,  both  the  pulmonary  and  systemic 
venous  circulations  go  on  without  any  assist- 
ance from  a  suction  power.     And 

3.  In  the  portal   circulation   of  the  higher 
animals  and  in  the  venous  circulation  of  fishes 
breathing  by  gills,  as  well  as  of  those  reptiles 
in  which  air  is  forced  into  the  lungs  by  a  process 
of  deglutition,  there  can  be  no  aid  derived  from 
a  suction  power. 

We  have  already,  in  our  description  of  the 
varieties  of  form  in  the  circulatory  organs  of 
animals,  adverted  to  the  intimate  relation  which 
very  generally  subsists  between  the  structure 
and  functions  of  the  organs  of  circulation  and 
respiration.  We  shall  now  mention  a  few 
other  circumstances  connected  with  the  func- 
tions of  circulation  in  the  adult  human  body, 
which  seem  to  depend  upon  this  relation  of  the 
motion  of  the  blood  to  the  respiration. 

The  influence  of  the  mechanical  operations 
of  respiration  is  not  confined  to  the  venous  cir- 
culation, for  it  has  been  shewn  by  direct  expe- 
riment that  the  force  of  the  blood  in  the  arteries 
varies  also  from  the  same  cause,  being  greater 
during  expiration  than  during  inspiration.  This 
greater  force  of  the  blood  in  the  arteries  during 
expiration,  known  to  Haller,  Lamure,  and 
Lorry,  was  proved  by  the  experiments  of  Hales, 
Poiseuille,  and  MagendieJ  formerly  mentioned. 

*  See  also  Macfadyen's  Remarks,  Edin.  Med. 
and  Sutg.  Journal,  vol.  xxii.  p.  271  ;  Carus  in 
Meckel's  Archiv.  iv.  p.  413  ;  and  Remarks  in  the 
Edin.  Journ.  of  Med.  Science,  vol.  ii.  p.  462. 

t  See  the  late  Prof.  Turner's  Essay  on  the  Mo- 
tions and  Sounds  of  the  Heart.  Med.  Chir.  Trans, 
of  Edin.  vol.  iii. 

J  Journ.  dc  Physiol.  vol.  i. 


CIRCULATION 


677 


II1C> 

S 


" 


It  is  very  probably  occasioned  in  part  by  the 
assistance  which  the  ventricular  systole  receives 
from  the  collapse  of  the  parietes  of  the  chest  at 
the  time  that  the  air  is  expelled  from  that  ca- 
vity, and  in  part  by  pressure  of  the  parietes  of 
the  chest  upon  its  contents,  and  through  them 
upon  the  trunks  of  the  larger  arteries.  During 
inspiration  the  pressure  must  be,  to  a  certain 
amount,  removed  from  the  larger  arteries,  and 
consequently  the  current  of  blood  through  them 
at  that  period  will  be  less  forcible  and  less 
rapid. 

The  well-known  fact  that  rupture  of  aneu- 
risms of  the  large  arteries  and  effusion  of  blood 
within  the  cranium  in  apoplexy  are  more  liable 
to  occur  during  straining  and  other  muscular 
efforts  associated  with  forcible  expiration,  is  a 
further  illustration  of  the  fact  that  the  arterial 
pressure  is  greatest  at  the  time  of  the  collapse 
of  the  parietes  of  the  chest. 

The  relation  of  the  force  and  frequency  of 
the  pulse  to  the  activity  of  the  respiration  is  an 
interesting  subject  connected  with  the  facts  at 
present  under  consideration.*  In  many  per- 
sons, in  ordinary  and  tranquil  respiration,  the 
force  and  frequency  of  the  pulse  vary  percepti- 
bly during  inspiration  and  expiration,  and  in 
these  persons,  when  the  respiration  is  more 
"  rcible  than  natural,  the  pulse  indicates  very 

stinctly  by  its  changes  the  varying  states  of 
the  chest.  During  an  unusually  long  and  for- 
cible inspiration  the  beats  of  the  pulse  are  more 
rapid  and  weaker,  and  during  a  succeeding 
complete  expiration,  or  even  while  the  chest 
is  kept  expanded,  the  pulse  is  more  full, 
strong,  and  slow.  Some  individuals  have  the 
power  of  occasioning  an  intermittent  pulse,  and 
some  of  causing  the  action  of  the  heart  to  cease 
even  by  forcible  exertion  of  the  expiratory  mus- 
cles. We  think  it  probable  that  it  may  have 
been  in  this  or  some  similar  indirect  manner 
that  the  action  of  the  heart  was  arrested  in 
Colonel  Townsend's  case,  described  by  Dr. 
Cheyne  in  his  work  on  the  English  malady, 
and  very  often  referred  to  as  a  proof  of  the  pos- 
session by  Colonel  Townsend  of  a  voluntary 
power  of  influencing  directly  the  heart's  action. 

There  is  in  general  a  very  constant  propor- 
tion in  the  ordinary  state  of  the  circulation  be- 
tween the  number  of  the  beats  of  the  pulse  and 
the  frequency  of  respiration.  The  average 
number  of  respirations  in  a  healthy  person  may 
be  considered  as  from  15  to  20  in  a  minute, 
and  taking  the  number  of  the  pulse  in  the  same 
time  at  from  72  to  75,  this  makes  one  complete 
respiratory  motion  for  nearly  four  beats  of  the 
heart.  The  force  and  frequency  of  the  heart's 
action  and  consequent  state  of  the  pulse  are 
well  known  to  be  considerably  influenced  by 
very  slight  muscular  efforts,  as  well  as  by 
changes  of  position  of  the  body  even ;  but  it  is 
not  observed  that  the  respiration  becomes  inva- 
riably more  or  less  hurried  in  a  corresponding 
degree  with  an  increased  or  diminished  fre- 
quency of  the  pulse.  In  very  violent  exercise, 
is  true,  and  more  particularly  in  rapid  mo- 


*  See  an  interesting  Essay  by  Bering  in  Tiede- 
mann's  Zeitschrift,  vol.  v. 


tions  which  give  rise  to  a  great  and  immediate 
increase  of  the  frequency  of  the  heart's  action, 
the  respiration  becomes  hurried  and  forcible,  or 
there  is  panting  ;  but,  on  the  other  hand,  it 
does  not  appear  that  the  gradual  changes  of  the 
pulse,  which  are  liable  to  occur  from  one  pe- 
riod of  the  day  to  another,  are  accompanied  by 
corresponding  variations  in  the  frequency  of 
respiration;  and  again,  when  by  a  voluntary 
effort  we  breathe  very  hurriedly,  as  for  example, 
from  80  to  100  times  in  a  minute,  the  fre- 
quency of  the  pulse  is  not  increased  by  more 
than  8  or  10  beats  in  a  minute.* 

Some  physiologists  hold  the  opinion  that  the 
motion  of  the  blood  in  the  capillaries  of  the 
lungs  and  the  system  is  considerably  influenced 
by  the  chemical  changes  which  the  blood  un- 
dergoes in  its  passage  through  the  minute  pul- 
monary and  systemic  vessels.  We  are  not  ac- 
quainted with  any  facts  or  experiments  which 
shew  that  the  systemic  capillary  circulation  is 
immediately  dependent  upon  the  change  of  the 
arterial  into  venous  blood :  on  the  contrary, 
such  an  opinion  is  much  opposed  by  the  facts 
that  a  free  circulation  of  imperfectly  arterialized 
blood  takes  place  in  the  foetus  before  birth,  as 
well  as  in  many  children  after  birth  affected  with 
malformations  of  the  heart  or  greater  vessels, 
and  that  a  completely  venous  blood  circulates 
through  the  system  in  hybernating  animals 
when  in  the  state  of  deepest  torpidity.  There 
are,  however,  several  circumstances  which  appear 
to  justify  the  opinion  that  the  motion  of  blood 
through  the  pulmonary  capillaries  has  a  more 
immediate  dependence  on  the  change  of  arte- 
rialization.f  In  all  those  circumstances  which 
cause  imperfect  respiration  and  prevent  the  ac- 
customed necessary  arterialization  of  the  blood, 
or  in  approaching  asphyxia,  it  seems  to  follow 
from  the  experiments  of  Dr.  Kay,  Alison,  and 
Reid,  that  there  occurs  from  the  very  first  com- 
mencement of  the  symptoms  of  impeded  respi- 
ration, a  diminution  of  the  quantity  of  blood 
which  passes  through  the  pulmonary  capillaries. 
There  is  thus  produced  from  the  first  com- 
mencement of  non-arterialization  of  the  blood 
an  accumulation  of  venous  blood  in  the  pulmo- 
nary capillaries  and  arteries,  but  it  is  equally 
well  proved  that  a  certain  quantity  of  venous 
blood  does,  as  Bichat  shewed,  gain  the  left 
side  of  the  heart  and  permeate  the  arterial  sys- 
tem. As  the  symptoms,  however,  of  suffocation 
or  asphyxia  become  more  urgent,  the  accumu- 
lation of  blood  in  the  pulmonary  artery  on  the 
right  side  of  the  heart  and  in  the  systemic  veins 
gradually  increases,  until  by  the  time  that  the 
involuntary  motions  of  respiration  have  ceased, 
there  appears  to  be  a  complete  stagnation  in  the 
lungs,  although  the  heart  continues  to  beat  a 
little  longer.  During  the  occurrence  of  these 
changes  the  action  of  the  heart  also  is  no  doubt 
gradually  becoming  weaker,  a  circumstance 
which  may  very  probably  contribute  to  the  stag- 
nation of  the  blood  in  the  lungs,  but  there  is  good 


*  See  an  account  of  the  interesting  experiments 
by  M.  Roulin  on  the  variations  of  the  pulse  at  diffe- 
rent heights.  Magendie's  Journ.  Jan.  1826. 

t  See  Dr.  Alison's  Remarks,  loc.  cit. 


078 


CIRCULATION. 


reason  to  think  that  the  motion  of  the  blood 
is  first  arrested  in  the  pulmonary  capillaries. 

The  state  of  our  knowledge  does  not,  it  must 
be  confessed,  permit  us  to  offer  a  satisfactory 
explanation  of  the  cause  of  the  above-men- 
tioned phenomena.  We  have  already  stated 
reasons  against  regarding  the  stagnation  of  the 
blood  in  the  lungs  in  asphyxia  as  attributable 
to  a  loss  of  the  supposed  vital  power  of  motion 
belonging  to  the  blood  in  the  capillary  vessels: 
and  we  think  it  quite  as  just  to  regard  the  stag- 
nation as  the  effect  of  over-stimulation  and 
constriction  of  the  minute  vessels  of  the  lungs 
by  the  dark  blood,  as  to  attribute  it,  in  the 
manner  some  have  done,  to  the  deficiency  of 
that  stimulation  which  arterial  blood,  without 
any  good  reason,  is  presumed  by  them  to  give 
to  the  small  vessels. 

2.  Circulation  within  the  cranium.  —  The 
limits  of  this  essay  do  not  permit  us  to  do  more 
than  allude  very  shortly  to  the  nature  of  the 
circulation  within  the  cranium, — a  subject,  in 
some  respects,  nearly  related  to  the  facts  just 
stated,  and  of  great  importance  from  the  general 
dependence  of  the  state  of  the  cerebral  func- 
tions upon  the  quantity  and  force  of  blood  which 
flows  through  the  brain. 

The  bloodvessels  within  the  cranium  are  dif- 
ferently situated  from  those  in  other  parts  of 
the  body  in  this  respect,  that  they  are  removed 
from  the  influence  of  atmospheric  pressure.  In 
consequence  of  the  unyielding  nature  of  the 
skull,  and  its  being  closed  on  all  sides,  except- 
ing at  the  places  where  the  nerves  and  blood- 
vessels pass  through  the  bones,  the  cavity  of  the 
skull  must  necessarily  be  equally  full  at  all 
times ;  and  the  spinal  canal  is  in  the  same  pre- 
dicament. 

The  whole  quantity  of  fluid  or  solid  matter, 
then,  within  the  cavity  of  the  cranium  and 
spinal  canal  must  be  always  the  same;  or, 
during  the  circulation  just  as  much  blood  must 
issue  as  enters  it,  and  it  is  physically  impossible 
to  increase  or  diminish  the  whole  quantity  con- 
tained in  the  brain  by  increased  pressure,  by 
opening  of  an  artery  or  vein  or  any  other  means. 
It  was  shewn  by  various  well  devised  experi- 
ments performed  by  the  late  Dr.  Kellie,*  that 
in  animals  bled  to  death,  while  the  rest  of  the 
body  was  exsangueous,  the  brain  retained  its 
usual  appearance  so  long  as  the  vault  of  the 
cranium  was  entire,  but  that  a  perforation  of  the 
skull,  such  as  to  allow  the  atmospheric  pressure 
to  act  upon  the  brain  and  bloodvessels  of  the 
head,  caused  the  evacuation  of  blood  from  the 
head  as  from  other  parts  of  the  body. 

While  the  whole  bulk  of  the  contents  of  the 
cranium,  however,  must  necessarily  remain  the 
same,  yet  the  relative  quantity  of  arterial  and 
venous  blood  may  vary  within  a  short  space  of 
time,  the  pressure  exerted  by  the  blood  in  the 
vessels  may  be  greater  or  less  according  to  cir- 
cumstances; and  there  may  occur  within  the 
skull  local  determinations  or  partial  distribu- 
tions of  the  blood.  When  from  rupture  of  a 
bloodvessel,  inflammation,  suppuration,  or  other 
causes,  blood,  serum,  or  pus  are  effused  into 

*  Edin.  Med.  Chirurg.  Trans,  vol.  i. 


the  cavity  of  the  cranium,  the  circulating  blood 
must  be  diminished  in  quantity;  when  there  is 
any  obstruction  to  the  return  of  the  blood  by 
the  jugular  veins,  the  pressure  of  the  blood  en- 
tering by  the  carotid  artery  is  proportionally 
greater;  and  when  the  arteries  which  supply 
blood  to  the  brain  are  obstructed,  or  the  heart's 
action  is  less  forcible  than  usual,  the  pressure 
on  the  brain  must  be  diminished  in  a  corre- 
sponding degree. 

In  the  natural  state  of  the  circulation  the 
pressure  exerted  by  the  blood  circulating 
through  the  cranium  is  subject  to  regular  alter- 
nations of  increase  and  decrease  from  the  effect 
of  the  heart's  action  and  the  motions  of  respira- 
tion. When  the  brain  of  man  or  of  animals  is 
exposed  by  the  removal  of  a  part  of  the  skull,  it 
is  seen  to  be  slightly  raised  at  the  exposed  part 
at  each  arterial  pulsation,  and  more  perceptibly 
during  each  expiration.  The  brain  falls  again 
during  each  succeeding  inspiration,  but  does 
not  sink  below  the  level  of  the  skull.  These 
motions  may  also  be  perceived  at  the  fontanelles 
of  the  infant's  head,  where  the  bony  parietes  of 
the  skull  are  deficient.  In  the  closed  state  of 
the  skull,  for  the  reasons  previously  mentioned, 
it  is  obvious  that  there  can  be  no  motions  simi- 
lar to  those  observed  in  the  brain  when  ex- 
posed, but  nevertheless  the  brain  must  be  more 
forcibly  pressed  upon  by  the  blood  at  these 
times  than  at  others.  Haller,  who  had  observed 
these  motions,  conceived  the  depression  during 
inspiration  to  be  caused  simply  by  the  ease 
with  which  the  blood  enters  the  chest  at  that 
time,  and  attributed  the  swelling  of  the  brain 
during  expiration  to  the  obstacle  then  offered 
to  the  descent  of  the  blood  through  the  jugu- 
lar veins.  It  seems,  however,  probable  that 
the  greater  fulness  of  the  arteries  during 
expiration  may  also  contribute  to  raise  the 
brain  at  the  time  when  the  collapse  of  the 
walls  of  the  chest  occurs :  for  Magendie  ob- 
served, that  when  a  ligature  was  put  upon  the 
jugular  vein,  the  blood  which  issued  from  this 
vein  by  an  aperture  above  the  ligature,  flowed 
with  greater  force  during  expiration,  shewing 
that  increased  arterial  pressure  during  expira- 
tion was  continued  through  the  capillaries  into 
the  veins.  Sign.  Ravina,  who  made  a  very 
extensive  series  of  experiments  upon  these  mo- 
tions, found  that  when  the  brain  has  been  de- 
pressed during  inspiration,  it  again  swells, 
although  no  expiration  succeeds,  but  that  when 
raised  during  expiration,  it  does  not  again  sink, 
if  inspiration  does  not  follow. 

3.  Influence  of  varieties  in  the  distribution 
of  arteries  and  veins  upon  the  circulation. — As 
connected  with  some  of  the  above-mentioned 
facts,  and  exerting  a  considerable  influence  in 
modifying  the  circulation  of  the  blood  in  parti- 
cular states  of  the  animal  economy,  we  may 
here  mention  a  few  of  the  more  remarkable 
varieties  in  the  distribution  of  the  arteries  and 
veins,  together  with  the  uses  they  have  been 
supposed  to  serve  in  different  animals.  The 
varieties  of  form  in  the  larger  arteries  may  be 
considered  under  two  heads;  a,  simple  tor- 
tuosity; and  b,  sudden  division  into  many 
small  branches. 


CIRCULATION. 


679 


a.  One  of  the  best  exam  pies  of  the  first  of  these 
varieties,  which  are  by  no  means  uncommon  in 
animals,  occurs  in  the  spermatic  arteries  of  the 
bull.     Two  reasons  have  been  assigned  for  the 
existence  of  this,  viz.  1,  to  allow,  by  the  greater 
length  of  the  vessel,  for  the  stretching  of  parts, 
as  in  the  arteries  of  the  lips ;  and  2,  to  dimi- 
nish the  velocity  of  the  blood  passing  through 
the  tortuous  vessel,  from  the  longer  course  and 
greater  incurvation.*     Increased  friction,  which 
must  be  the  consequence  of  greater  length  of 
the  artery,   will  diminish  the  velocity  of  the 
blood  through  the  whole  vessel,  and  besides 
this,  a  given  particle  of  blood  passing  through 
a  tortuous  vessel  will  arrive  later  at  its  destina- 
tion, in  consequence  of  the  longer  course  it  has 
to  run  through;  but  if  we  regard  the  fluid  in 
the  arteries  as  every  where  subjected  to  pres- 
sure, it  is  veiy  doubtful  that  the  increased  cur- 
vature can  be  the  source  of  any  considerable 
retardation  by  diminishing  the  force  communi- 
cated by  the  impulses  of  the  heart.f 

b.  The  sudden   division   of  an  artery  into 
many  small  branches  may  take  place  with  or 
without  tortuosity  or  a  plexiform  arrangement ; 
the  primitive  vessel  disappearing  or  persisting, 
but  in  most  cases  when  present,  diminished  in 
size.    The  most  remarkable  examples  of  this 
peculiarity  of  the  arterial  system  are  the  follow- 
ing.    1.  The  intercostal  and  lumbar  arteries  of 
the  Cetacea  in  the  posterior  part  of  the  chest, 
and  in  the  vertebral  canal  and  the  caudal  artery 
of  the  same  animals,  which  are  tortuous  and 
plexiform.     2.  The  brachial  artery  of  the  Por- 
poise, which  divides  at  once  into  more  than 
forty  plexiform  branches.     The  primitive  trunks 
disappear,  and  five  or  more  vessels  emerge  from 
the  distal  end  of  the  plexus.    The  uterine  and 
vesical  arteries  of  the  same  animal  are  much 
divided,  but  not  plexiform. J     3.  The  subdi- 
vided brachial  and  crural  arteries  of  the  Bra- 
dypus     tridactylus,    Lemur     tardigradus,    L. 
gracilis  and  L.  tarsius ;  and  the  same  arteries, 
as  well  as  the  caudal  arteries  of  the  Myrme- 
cophaga    didactyla  and   M.  tetradactyla.      4. 
The  arteries  of  the  legs  of  the  Swan,  Goose, 
and  Turkey  divide  into  several  long  branches, 
which  anastomose  with  one  another.§     5.  The 
rete  mirabile  of  Galen  on  the  internal  carotid 
of  many  quadrupeds,  and  the  rete  mirabile  on 
the  common  carotid  of  the  Frog.     6.  The  rete 
mirabile  of  Hovius  on  the  ophthalmic  artery  of 
some  animals,  the  Seal  for  instance.     7.  The 
mesenteric  arteries  of  the  Sow  at  their  com- 
mencement.    8.  The  subcutaneous  arteries  of 
the  Hedgehog. 

The  uses  of  these  very  various  forms  of  arte- 
ries it  must  be  confessed  is  very  little  known. 
Some  of  them  may,  like  other  peculiarities  in 
animal  structure,  and  more  especially  those  be- 
longing to  the  vascular  system,  be  remains  of 
the  fetal  condition  of  the  arteries  in  which 

*  J.  Hunter. 

t  Mullet's  Physiol,  vol.  i.  p.  198. 

\  See  the  accounts  of  these  varieties  hy  J.  Hun- 
ter in  the  Phil.  Trans.  Sharpey,  Meeting  of 
British  Scient.  Assoc.  in  Edin.  Sept.  Ih34.  Breschet, 
Annal.  des  Scien.  Natur.  1834.  Baer,  Nov.  Act. 
Nat.  cur.  1835. 

§  Cuvier,  Lemons  d'Anat.  Cotnp.  vol.  iv. 


they  exist.*  The  most  common  opinion  enter- 
tained as  to  their  effect  on  the  circulation  is 
that  they  retard  the  velocity  of  the  blood,  and 
render  its  flow  more  uniform,  thus  preventing 
the  parts  supplied  by  them  from  being  affected 
by  sudden  changes.f  Other  secondary  conse- 
quences of  the  diminished  velocity  occasioned 
by  these  peculiar  structures  have  been  imagined, 
as  for  example,  1,  diminished  rapidity  and 
greater  durability  of  muscular  contraction,  as 
in  the  Sloths;]:  2,  security  against  obstruction 
of  the  circulation  from  pressure,  as  in  climbing 
animals  which  cling  long  and  forcibly  to  branches 
of  trees  ;§  3,  or  these  plexuses  have  been  regard- 
ed as  intended  to  increase  the  capacity  of  the 
arterial  system,  and  to  serve  as  reservoirs  for 
blood,  as  may  be  the  case  in  the  Cetacea.||  In 
some  of  the  above-mentioned  animals  the  tor- 
tuosity or  multiplied  divisions  of  the  arteries 
are  accompanied  by  a  similar  condition  of  the 
veins,  as  in  the  Porpoise. 

The  most  remarkable  variety  in  the  form  of 
the  venous  system,  and  the  one  to  which  a  use 
may  be  most  easily  assigned,  is  the  large  dila- 
tation of  the  vena  cava  inferior  in  the  neigh- 
bourhood of  the  liver,  which  occurs  in  those 
animals  which  from  their  mode  of  life  are  in  the 
habit  of  remaining  long  under  water,  such  as 
the  Seal,  Otter,  and  Diving  Birds.  The  pur- 
pose of  the  venous  sinuses  in  these  situations  is 
manifestly  to  allow  of  the  accumulation  of 
venous  blood  in  the  vena  cava  without  an  un- 
usual distension  of  the  right  side  of  the  heart 
and  bloodvessels  leading  into  it  and  from  it, 
which  is  the  effect  of  long  submersion  or  im- 
peded respiration  in  animals  unprovided  with 
this  peculiarity  of  structure.  The  venous  and 
arterial  plexuses  of  the  Cetacea  very  probably 
serve  the  same  purpose.  The  muscularity  of 
these  sinuses  alleged  by  some  must  have  the 
effect  of  emptying  them  more  easily  than  would 
be  accomplished  by  the  vis  a  tergo. 

4.  Influence  of  the  nervous  system  upon 
the  circulation. — It  is  a  very  general  opi- 
nion among  physiologists  that  a  considerable 
influence  is  exerted  by  various  parts  of  the 
nervous  system  upon  the  function  of  circu- 
lation as  a  whole,  and  through  it  upon  the 
different  processes  of  the  economy  concerned 
with  nutrition,  as  digestion,  secretion,  growth, 
animal  heat,  &c.  There  is  some  difficulty, 
however,  in  ascertaining  the  exact  relation 
which  subsists  between  particular  parts  of  the 
nervous  and  circulatory  systems.  It  is  mani- 
fest that  in  many  instances  the  circulation  in 
the  bloodvessels  is  modified  by  a  nervous  in- 
fluence which  operates  on  the  heart  alone,  while 
in  others  it  is  affected  by  an  alteration  of  the 
vital  powers  of  the  bloodvessels  themselves. 
We  refer  the  reader  to  the  articles  CONTRAC- 
TILITY and  HEART  for  an  account  of  the 
modifications  to  which  the  circulation  is  liable 
from  the  operation  of  nervous  influence  on 

*  Baer,  loc.  cit. 

f   Barclay  on  the  Arteries,  p.  36. 
J  Carlisle,    Phil.  Trans.    1800.     Roget,  Bridge- 
water  Treatise. 
Vrolik. 
J.  Hunter,  loc.  cit. 


680 


CIRCULATION. 


the  heart  alone.  We  shall  only  remark  in 
this  place  that  although  the  heart  may  be 
excited  to  contraction  by  the  direct  stimu- 
lation of  its  muscular  substance,  and  although 
the  effect  upon  the  heart's  action  of  bodily 
exertion,  of  emotions  of  the  mind,  and  of 
severe  injuries  of  the  brain  and  spinal  mar- 
row, all  of  which  can  be  supposed  to  act  upon 
the  heart  through  the  nerves  only,  are  un- 
doubted ;  yet  it  is  well'  ascertained  that  the 
heart  cannot  in  general  be  excited  to  con- 
traction by  the  direct  stimulation  of  its  nerves, 
and  that  its  action  may  be  regarded  as  auto- 
matic to  a  certain  degree,  and  little  dependent 
upon  the  immediate  transmission  to  it  of  any 
nervous  influence  from  the  cerebro-spinal  or 
ganglionic  nervous  systems,  since  the  rythmic 
contraction  of  the  heart  continues  to  go  on  for 
a  time  in  some  animals  after  the  division  of  its 
nerves,  and  in  others  even  after  its  complete 
separation  from  the  body.  It  has  also  been 
frequently  found  that  after  the  complete  de- 
struction of  the  brain  and  spinal  marrow  of  an 
animal  the  circulation  of  the  blood  can  be 
maintained  for  some  time  by  means  of  artificial 
respiration, — an  experiment  which  proves  that 
the  motion  of  the  blood  in  the  vessels  is  not 
immediately  dependent  upon  nervous  influ- 
ence.* 

Many  circumstances,  however,  seem  to  shew 
that  the  state  of  the  vessels,  and  in  consequence 
of  this  the  velocity  and  force  of  the  blood,  are 
susceptible  of  very  considerable  modification 
from  local  affections  of  the  nerves  belonging  to 
the  part  in  which  they  may  have  been  observed 
to  occur,  or  from  general  alterations  of  the 
nervous  powers  of  the  system.  It  is  probable 
that  nervous  influence  operates  much  more 
powerfully  in  modifying  the  circulation  through 
the  small  than  through  the  large  vessels,  indeed 
we  know  of  no  direct  satisfactory  experiments 
which  demonstrate  the  effect  of  nervous  in- 
fluence upon  the  larger  arteries  exclusively. 

The  experiments  which  seem  to  prove  most 
satisfactorily  the  influence  of  the  nervous  system 
on  the  circulation  in  the  small  vessels  are  those 
performed  on  cold-blooded  animals  by  Legal- 
lois,f  W.  Philip, J  Flourens,  and  particularly 
those  of  Marshall  Hall,§  the  general  result  of 
which  may  be  stated  as  the  following :  that  after 
the  destruction,  whether  sudden  or  gradual,  of 
the  brain  or  spinal  marrow,  the  flow  of  blood 
in  the  remote  parts  becomes  more  languid 
and  is  gradually  more  and  more  circumscribed, 
while  the  action  of  the  heart  continues,  and  its 
power  seems  not  to  be  diminished  in  a  propor- 
tional degree.  But  in  such  experiments  as  those 
just  mentioned,  performed  in  general  in  cold- 
blooded animals,  it  must  be  at  all  times  ex- 
ceedingly difficult  to  find  an  accurate  mode  of 
measuring  the  force  of  the  heart,  and  conse- 

*  We  refer  here  to  the  experiments  of  Haller, 
Whytt,  Fontana,  Spallanzani,  Legallois,  W.  Philip, 
Cli.t,  Flourens,  and  Miiller ;  Humboldt,  Fowler, 
Brachet,  Treviranus,  Weinhold,  &c. 

f   Exper.  sur  le  Principe  de  la  Vie. 

j  Exper.  Inquiry  into  the  Laws  of  the  Vital  Func- 
tions. 

§  Loc.  citat.  p.  99. 


quently  they  cannot  be  regarded  as  affording 
sufficient  evidence   that   there  did   not  occur 
along  with  the  languid  state  of  the  circulation 
a   certain   diminution   in    the    heart's   power. 
They  do  not  at  least  entitle  us  to  conclude  that 
the  decreased  velocity  and  stagnation  of  the 
blood  in  the  remote  parts  is  caused  mainly  by 
the  loss  of  the  vital  powers  of  the  capillary 
vessels,  for  these   changes  of  the  circulation 
may  in  a  great  measure  be  the  effect  of  other 
causes,  as  the  loss  of  power  of  the  heart,  and 
that  more  permanent  alteration  of  the  textures 
which   very   probably   accompany   the   severe 
injury  done  to  the  body.     On  the  other  hand 
it  may  be  remarked  that  the  coldness  and  im- 
paired nourishment  common  in  palsied  limbs, 
the  known  increase  or  diminution  of  the  various 
secretions  from  mental  emotions,  and   direct 
or  sympathetic  affections  of  the  nerves  belong- 
ing to  the  glands   or  other  secreting  organs, 
the  phenomena  of  blushing,  erection,  inflam- 
mation, and   the  like  are  all  very  direct  and 
satisfactory  proofs  that  the  small  vessels  and 
the  capillary  circulation  may  be  influenced  by 
affections  of  the  nerves.     As  a  further  confirma- 
tion of  this  may  be  mentioned,  1,  the  inflamma- 
tion and  other  consequences  of  the  division  of 
the  fifth  pair  of  nerves  which  occur  in  the  eye; 
2,  the  statement  of  some,  as  Treviranus,  that 
the  division  of  the  nerves  of  the  leg  of  a  frog 
impedes  the   circulation:   3,  the  assertion   by 
others,  as  Baurngartner,  that  after  the  division 
of  the  nerves  or  the  destruction  of  the  spinal 
marrow,    the   peculiar  oscillations  which   he, 
along  with  Doellinger  and  Kaltenbrunner,  has 
observed  to  precede  the  formation  of  new  blood- 
vessels do  not  occur ;  and  4,  the  observations 
of  Nasse,  which  are  stated  to  shew  that  the 
reunion  of  wounds  is  retarded  or  put  a  stop  to 
by  the  division  of  the  nerves  belonging  to  the 
wounded  part.     Krimer,*  whose  experiments 
on    this    subject  are   numerous   and    remark- 
able, states  that  the  circulation  was  always  much 
impaired  by  the  abstraction  of  nervous  influ- 
ence from  the  division  or  ligature  of  the  nerves; 
that  the  jet  from  the  femoral  artery  of  a  qua- 
druped was  much  less  strong  after  the  division 
of  the  crural  nerve ;  that  the  capillary  circula- 
tion of  the  frog's  web  ceased  soon  after  the 
nerves  were  cut  or  tied ;  that  the  arterial  blood 
passed  through  the  systemic  capillaries  without 
undergoing   its   proper   change    into  venous ; 
and  that  salt  did  not  produce  the  accustomed 
effect  of  dilating  the  capillaries  when  the  nerves 
of  the  part  were  injured,  but  that  these  effects 
were    induced   when    galvanic   irritation   was 
applied  to  the  divided  nerve. 

In  reference  to  these  experiments  it  may  be 
remarked  that  most  of  them  are  at  variance 
with  experiments  of  a  similar  nature  performed 
by  others,  more  especially  those  of  Haller, 
Spallanzani,  Whytt,  Fontana,  Legallois,  W. 
Philip,  Flourens,  and  M.  Hall,  none  of  whom 
remarked  so  immediate  and  complete  a  stoppage 
of  the  circulation  from  removal  of  the  nervous 
influence.  Again,  in  palsied  limbs  the  circu- 
lation is  frequently  little  or  not  at  all  disturbed, 

*  Physiologische  Untersuchungen.  Leipzig,  1820. 


CIRCULATION. 


681 


and  sometimes  the  secretions,  natural  growth 
of  parts,  and  reunion  of  wounds  have  been 
found  to  be  little  impaired  by  injuries  of  the 
nerves.  We  may  therefore  form  the  conclu- 
sion, that  although  the  circulation  in  the  small 
vessels  is  obviously  liable  to  be  modified  by 
the  state  of  the  nerves  in  their  neighbourhood, 
or  perhaps  by  affections  of  the  nervous  system 
in  general,  there  is  no  reason  to  consider  the 
capillary  circulation  as  more  immediately  de- 
pendent on  nervous  influence  than  the  action 
of  the  heart. 

BIBLIOGRAPHY.— We  have  deemed  it  advisable 
to  reserve  our  historical  sketch  of  the  discovery  of 
the  circulation  and  the  knowledge  of  that  impor- 
tant portion  of  physiology  to  this  part  of  the  article, 
thereby  consulting  brevity  in  uniting  it  with  the 
literature  of  the  subject. 

The  Chinese  have  been  conceived  to  have  enter- 
tained correct  notions  of  the  circulation  before  they 
had  any  intercourse  witli  Europe, — a  supposition, 
the  erroneousness  of  which  is  sufficiently  demon- 
strated by  their  description  of  the  commencement 
of  the  circulation  of  the  radical  humours  and  vital 
heat  at  three  o'clock  in  the  morning,  their  passage 
through  the  lungs  in  the  course  of  the  day,  and 
termination  in  the  liver  at  the  end  of  twenty-four 
hours,  as  well  as  by  the  different  manipulations 
practised  by  them  in  the  operation  of  venesection. 

In  the  time  of  Hippocrates  and  Aristotle,  al- 
though the  principal  bloodvessels  were  described — 
apparently  from  dissection  of  animals, — the  course 
of  the  blood  appears  to  have  been  wholly  un- 
known. 

Towards  the  end  of  the  second  century  Galen 
describes  accurately  the  distribution  of  many  of 
the  bloodvessels  in  the  lower  animals.  He  ap- 
pears also  to  have  known  the  anastomoses  of  the 
arteries  and  veins,  and  the  structure  and  uses  of 
the  foramen  ovale  in  the  foetus,  but  his  works 
afford  no  evidence  of  his  having  known  the  course 
of  the  blood  in  either  the  pulmonic  or  the  systemic 
circulations.  He  described  the  arteries  as  arising 
from  the  heart,  the  veins  from  the  liver  ;  and  some 
of  those  passages  of  his  works  in  which  it  is 
alleged  that  the  circulation  of  the  blood  is  pointed 
out,  are  either  inconsistent  with  one  another,  or 
are  believed  to  have  been  introduced  at  a  later 
time  than  Galen's.  Galen  believed  that  the  blood 
passed  through  the  septum  of  the  ventricles ;  he 
knew  that  the  arteries  contained  blood,  but  he 
believed  its  motion  to  be  of  an  oscillatory  kind. 
(De  usu  partium,  1.  iv.,  vi.,  &  vii.,  and  his  trea- 
tise on  the  question — an  sunyuis  in  arteriit  ruitura 
continetur  ?) 

The  authors  of  a  more  recent  date,  in  whose 
works  it  has  been  supposed  that  the  circulation  was 
described,  are  Servetus,  Columbus,  and  Caesal- 
pinus. After  the  revival  of  letters,  the  great  ana- 
tomist Vesalius  of  Brussels,  in  1542,  had  examined 
more  minutely  than  his  predecessors  the  connec- 
tions of  the  arteries  and  veins :  he  mentions  the 
valves  of  the  veins,  the  difference  between  the 
veins  and  arteries,  and  describes  the  valves  of  the 
heart.  He  seems  to  have  known  that  the  blood 
was  propelled  into  the  arteries  by  the  heart,  and 
demonstrated  by  a  more  direct  experiment  than 
Galen's,  that  the  arterial  pulse  depends  on  the 
systole  of  the  heart.  (De  corporis  humani  fabrica, 
fol. ;  and  Opera  Omnia,  cura.  Boerhaave.) 

Servetus,  the  victim  of  religious  persecution  in 
1553,  is  one  of  those  in  whose  writings  we  find  the 
first  dawn  of  part  of  the  discovery  of  Harvey,  for 
he  very  distinctly  at  one  place  refers  to  the  pulmo- 
nary circulation.  The  vital  spirit  (blood)  passes 
by  the  arteries  into  the  veins  by  their  anastomoses. 
The  blood  cannot  pass  from  the  right  into  the  left 
auricle  on  account  of  the  closed  nature  of  the  sep- 

VOL.  I. 


turn  auricularum ;  in  the  adult  it  must  go  through 
the  lungs,  where  it  is  charged  with  the  vital  spirit 
obtained  from  the  atmospheric  air,  and  then  returns 
to  the  heart.  He  further  held  that  the  pulmonary 
artery  and  vein  from  their  large  size  must  have 
some  other  use  than  the  nourishment  of  the  lungs 
merely.  De  Trinitatis  Erroribus.  Basil,  1531. 

Columbus,  Professor  at  Padua  and  Rome,  six 
years  after  the  publication  of  the  work  of  Servetus, 
published  the  discovery  of  the  lesser  circulation  as 
his  own.  He  describes  it  more  clearly  than  Ser- 
vetus does,  and  held  that  the  blood  returning  from 
the  lungs  is  not  mixed  with  vital  spirit,  but  is  quite 
pure.  Libri  xv.  De  re  anatom.  Venetiis,  1559. 

Caesalpinus  of  Arezzo,  Professor  at  Pisa,  gave, 
in  1583,  a  more  detailed  description  of  the  pul- 
monary circulation  than  any  of  those  who  preceded 
him,  and  in  two  parts  of  his  work  expresses  him- 
self in  such  a  manner  as  to  shew  that  he  had  some 
idea  of  the  systemic  and  double  circulation.  Other 
passages  in  his  works  are,  however,  quite  incon- 
sistent with  a  correct  knowledge  of  the  course  of 
the  blood,  and,  although  we  find  this  course  more 
nearly  indicated  in  the  writings  of  Caesalpinus 
than  in  any  others  before  the  time  of  Harvey,  he 
does  not  seem  to  have  added  much,  if  any  thing, 
to  the  knowledge  possessed  by  those  who  preceded 
him,  but  rather  to  have  applied,  and  without 
acknowledgement,  the  observations  of  Vesalius, 
Fallopius,  Servetus,  and  Columbus,  to  the  expla- 
nation of  the  circulation. 

The  foetal  circulation  seems  to  have  been  ex- 
amined with  great  attention  by  the  anatomists  of 
the  sixteenth  century.  Galen  had  already  been 
acquainted  with  the  foramen  ovale,  and  also  knew, 
though  less  perfectly,  the  ductus  arteriosus.  Fal- 
lopius described  the  ductus  arteriosus  exactly, 
so  also  did  Vesalius  and  .Ar.tn/ii;  and  after  this 
Botallus  appropriated  to  himself  the  discovery  of 
both  the  foramen  ovale  and  ductus  arteriosus. 
Vesalius  discovered  the  ductus  venosus  which  was 

r"  red  by  Fabricius  and  Eustachius.  Fabricius 
Aquapendente  made  the  discovery  of  the  valves 
of  the  veins  and  published  it  in  1603  :  it  is  sur- 
prising that  knowing  their  structure  so  perfectly  as 
he  did,  he  should  have  continued  ignorant  of  their 
uses,  and  stricily  attached  to  the  older  erroneous 
opinions  regarding  the  circulation. 

Dr.  William  Harvey  was  born  at  Folkstone  in  Kent, 
and  studied  under  Fabricius  at  Padua  from  1598 
to  1602.  Learning  from  his  master  the  structure 
of  the  valves  of  the  veins,  he  engaged  in  experi- 
mental researches  after  returning  to  England,  with 
the  view  of  determining  their  uses,  and  in  1619, 
according  to  his  own  statement,  taught  publicly  for 
the  first  time  the  doctrine  of  the  double  circulation 
of  the  blood,  which  he  had  demonstrated  by  his 
investigations.  He  did  not  publish  any  history  of 
this  discovery  until  after  the  lapse  of  nine  years, 
during  which  he  had  carefully  examined  his  doc- 
trines and  experiments.  This  appeared  in  the 
Excrcitaiio  Anatomica  de  Motu  Cordis  et  Sanguinis 
in  Animalibus.  first  published  at  Frankfort  in 
1628. 

Among  the  contemporaries  of  Harvey  who  sup- 
ported his  views,  the  following  authors  are  re- 
markable. 

Werner  Rolfink,  Professor  at  Jena,  one  of  the 
first  to  adopt  the  new  view,  published  two  years 
after  the  publication  of  Harvey's  work. 

DesCartesupon  two  occasions  supported  Harvey's 
views,  viz.  in  1637  and  1643,  having  been  answered 
by  Plempius. 

John  Walaeus,  Professor  at  Leyden,  may  be 
regarded  as  one  of  the  most  original  of  those  who 
adopted  and  defended  the  new  view.  In  1640  he 
published  two  letters,  addressed  to  Thomas  Bar- 
tholin. 

Herman  Conring  of  Hermstadt. 

James  de  Back,  Amsterdam,  1649. 

John  Trullius  1651,   Rome. 

2  Y 


682 


CIRCULATION. 


George  Ent  of  London. 

Riolan  was  the  only  one  of  his  opponents  whose 
objections  Harvey  thought  it  worth  while  to  answer. 
This  he  did  in  two  additional  Exercitationes,  which 
are  published  in  the  Leyden  edition  of  his  works, 
1737.  In  a  journey  which  Harvey  made  to  Ger- 
many, he  endeavoured  to  demonstrate  his  views 
to  Hoffman,  but  without  success.  In  1652  Plem- 
pius  acceded  the  merit  of  discovery  to  Harvey,  and 
adopted  his  views  of  the  circulation.  Harvey  died 
at  the  advanced  age  of  79,  in  the  year  1657,  after 
having  had  the  satisfaction  of  seeing  his  views 
generally  adopted  by  the  best-informed  anatomists 
and  physiologists,  and  after  having  enjoyed  the 
glory  due  to  so  great  and  valuable  a  discovery. — 
The  best  edition  of  Harvey's  treatise  on  the  Circu- 
lation is  that  to  be  found  in  the  edition  of  his  works 
published  by  the  London  College  of  Physicians, 
in  4to. 

About  this  time  the  experiment  of  transfusion, 
proposed  some  time  previously,  se3ms  to  have  been 
first  successfully  performed  by  Dr.  Timothy  Clarke, 
Boyle,  and  Henshaw,  as  also  by  the  celebrated 
Lower  at  Oxford,  in  1660,  affording  additional 
proof  of  the  correctness  of  the  views  of  Haivey. 

Although  the  double  course  of  the  blood  through 
the  pulraonic  and  systemic  circulations  was  fully 
demonstrated  by  these  investigations,  the  direct 
passage  of  the  blood  from  the  smaller  arteries  into 
the  veins  had  not  yet  been  observed. 

After  the  introduction  of  the  use  of  the  mi- 
croscope, this  additional  proof  was  supplied  by 
Malpighi,  who  discovered  the  capillary  circulation 
in  the  vessels  on  the  lungs  and  mesentery  of  the 
frog  in  1661  (Epistola  de  pulmonibus). 

Malpighi  observed  the  passage  of  the  globules 
of  fie  blood  through  the  minute  vessels,  and  thus 
satisfactorily  proved  that  there  is  an  actual  trans- 
mission of  the  circulating  blood  from  the  arteries 
to  the  veins  in  both  the  systemic  and  pulmonary 
circulations. 

Leuwenhoeck,  in  1673,  repeated  the  observations 
of  Malpighi  on  the  capillary  circulation,  and 
extended  them  to  different  animals,  at  the  same 
time  adding  to  their  value  by  the  discovery  of  the 
nature  of  the  colouring  particles  or  globules  of 
the  blood  (Philos.  Trans.  No.  102).  The  structure 
of  the  minute  vessels  in  different  parts  of  the 
human  body  was  shortly  after  this  very  fully  shewn 
by  the  fine  injections  of  Ruysch,  and  the  analogy 
between  the  structure  of  the  minute  vessels  in  Man 
and  the  lower  animals  thus  fully  established. 

For  the  history  of  the  discovery  of  the  Circula- 
tion, we  would  refer  the  reader  to  the  following  works. 

Bostock's  Elementary  system  of  physiology,  vol.  i. 
p.  343.  Holler's  Elementa,  vol.  i.  p,  340.  Senac, 
Traite  du  creur,  Introduct.  p.  68.  Sabatier,  Ana- 
tomic, ii.  p.  255.  Portal,  Hist,  de  1'anatomie  et 
de  chirurgie,  t.  ii.  p.  468.  Sprengel's  History  of 
medicine,  French,  vol.  iv.  p.  85.  Hecker's 
Gerschichte  der  Medezin,  Hecker's  Lehre  vom 
Kreislauf  von  Harvey,  Berlin,  1831.  Barrellotti, 
Dialogo  sulla  scoperta  della  circolazione  del  sangue 
nel  corpo  umano,  Pisa,  1831. 

When  the  course  of  the  blood  in  the  double 
circulation  had  been  fully  established  by  the  above- 
mentioned  observers,  and  the  views  of  Harvey 
were  universally  adopted,  the  labours  of  anatomists 
and  physiologists  were  directed  to  the  more  minute 
and  detailed  investigation  of  the  different  processes 
of  the  circulatory  function. 

The  works  of  Lower,  Lieutaud,  and  Senac  on 
the  heart,  and  of  Hales,  Haller,  and  Spallanzani 
on  the  motion  of  the  blood,  were  among  the  more 
important  of  those  which  appeared  during  the  last 
century  which  contributed  to  advance  the  knowledge 
of  our  subject. 

The  second  volume  of  Dr.  Stephen  Hales's 
Statical  Essays,  1733,  contains  the  history  of  the 
numerous  experiments  made  by  that  ingenious 
philosopher,  with  a  view  to  investigate  the  hy- 


draulic phenomena  of  the  circulation  and  the  first 
accurate  measurements  and  calculations  of  the  force 
of  the  current  of  blood  in  the  arteries  and  veins, 
its  velocity,  the  power  of  the  heart,  &c. 

The  works  of  Haller  on  the  circulation  consist, 

1st,  of  the  greater  part  of  the  first  and  second 
volumes  of  the  Elementa,  containing  a  complete 
history  of  the  structure  and  functions  of  the  organs 
of  circulation ; 

2d,  Deux  memoires  sur  le  mouvement  du  sang, 
&c.  Lausanne,  1756  :  the  first  memoir  containing 
the  results,  the  second  a  detailed  account  of  the 
experiments. 

These  Memoirs  are  also  published  in  the  Opera 
Minora  ;  also,  in  English,  Lond.  1757. 

3d,  Deux  mem.  sur  la  formation  du  coeur  dans 
le  poulet,  Laus.  1758. 

The  work  of  Spallanzani,  entitled  Experiments 
upon  the  Circulation  of  the  Blood,  translated  by 
Tourdes  into  French,  Paris,  An  viii.,  and  by  R.  Hall, 
M.D.  into  English,  Lond. 1801,  contains  a  great  body 
of  most  accurate  observations  and  experiments. 

The  first  two  Memoirs  are  on  the  circulation 
throughout  the  vascular  system. 

The  next  two  on  the  phenomena  of  the  languid 
circulation,  on  the  motion  of  the  blood  independent 
of  the  action  of  the  heart,  and  the  pulsation  of 
the  arteries. 

Circulation  in  general. —  Young  on  the  circulation, 
Phil.  Trans.  1809.  Lund's  Results  of  modern 
physiological  vivisections,  12mo.  Copenhagen, 

1825,  translated    in    the     Journal    Complement, 
t.  xxiv.-v.  &c.     Bourdon,  Pur  le  mecanisme  de  la 
circulation,  8vo.    Paris,  1820.      W.  Philip,    Phil. 
Trans.  1832.     M.  Hall,  Reply  to  W.  Philip,  Med. 
Gaz.  x.  695.     Physiol.   of    the   circulation,    Med. 
Chir.  Review,  vol.  iv.  1823-4,    p.  38.      Flourens, 
Memoires  de  1'Institut.  vol.  x.     Herbst,    De  san- 
guinis  quantitate,  1822.    Schwenke,  Hist,  sanguinis. 
J.  Wilson,  Essay  on  the  blood  and  vascular  system, 
Lond.  1819.     Kerr,  Observations  on  the  Harvcian 
doctrine  of  the  circulation  of  the  blood,  Lond.  1819  ; 
(doubts  the    Harveian   view.)       Charles  Bell,    An 
essay   on   the    forces   which    circulate   the    blood, 
Lond.  1819.     Oesterreicher,  Versuch  einer  Darstel- 
lung  der  Lehre  vom  Kreislauf  des  Blutes,  Nurnb. 

1826.  Wedemeyer,  Untersuch.  uber  den  Kreislauf 
des  Blutes  insbesond.  uber  die  Bewegung  desselben 
in  den  Arterien  und  Capillargefassen,&c.  Hannover, 
1828 ;    also   in   English.      Reichel,    De    sanguine 
ejusque  motu   exper.    Lips.    1767.       Jaeckel,    De 
motu  sanguinis  comment.   Vratisl.  1821.      Sarlan- 
diere,  Mem.  sur  la  circulation  du  sang,  &c.  Paris, 
1822.     Jos.  Swan,  Essay  on  the  connection  between 
the  action  of  the  heart  and  arteries  and   the  func- 
tions of  the  nervous  system,  Lond.  1829.     Rose, 
Diss.    de    motu    sang,    naturali   et   praeternaturali, 
Helmstad.  1668.     Maertens,    Diss.   de  circulatione 
sanguinis,  Helmstadt.    1739.     Araldi,  Della  forza 
e  deir  influsso   del    cuore  sul  circolo  del   sangue, 
Mem.  della  Soc.  Ital.  in  Mod.  1804,  vol.  xi. 

Heart. — Barry  on  the  circulation  through  the 
heart,  &c.  Annal.  d.  Sc.  Nat.  xi.  p.  113.  Borelli, 
De  motu  animalium,  1743.  Passavant  (Bernouilli), 
De  vi  cordis,  1748.  Hales's  Statical  essays, 
vol.  ii.  1733.  Poiseuille,  Sur  la  force  du  cceur 
aortique,  Breschet's  Repert.  vi.  1828,  and  Ma- 
gendie's  Journ.  Whytt  on  the  heart,  Works, 
p.  16.  Williams  on  the  motive  powers  of  the 
heart,  Edin.  Med.  and  Surg.  Journ.  xxi.  268. 
Bartholin  on  the  suction-power  of  the  heart,  Anat. 
8vo.  p.  371.  Senac,  Traite  du  creur,  1749.  Wil- 
degans  on  the  same,  1772.  A.  Wilson,  Inquiry 
into  the  moving  powers  employed  in  the  circulation 
of  the  blood,  8vo.  Lond.  1774.  Jurin.  De  po- 
tentia  cordis,  Phil.  Trans.  1718  and  1719.  James 
Keill,  Essays  on  several  parts  of  the  animal  economy, 
4th  ed.  with  a  Diss.  on  the  force  of  the  heart, 
8vo.  Lond.  1738.  Prochaska,  Opera  Min.  1800, 
Controv.  physiol. 

Arteries. — In  addition  to  the  works  referred  to 


CIRRHOPODA. 


683 


in  the  Bibliography  of  ARTERY,  the  following  are 
deserving  of  notice  : — Thomsons  Lect.  on  Inflam- 
mation. Roulin  on  variations  of  the  pulse  at 
different  heights,  Magendie's  Journ.  Jan.  1826. 
Poiseuille  on  the  contractility  of  arteries,  Magendie's 
Journ.  vol.  viii.  On  the  dilatation  of  arteries, 
ibid,  vol.  ix.  44.  Weber,  H.  E.  De  pulsu  in  om- 
nibus arteriis  plane  non  synchronico,  Annotat. 
Academ.  1835.  Mich.  Jiiger,  Tract,  anat.  physiol. 
de  arteriarum  pulsu,  Wirceb.  1820.  Reinarz, 
Diss.  de  arteriarum  irritabilitate  propria,  Bonnae, 
1821.  Kramp,  De  vi  vitali  arteriarum,  Argentor. 
1786. 

Veins,  and  connection  of  respiration  with  circu- 
lation.— James  Carson,  Inquiry  into  the  causes  of 
the  motion  of  the  blood,  Liverpool,  1815.  On  the 
empty  state  of  the  arteries  after  death,  Med.  Chir. 
Trans,  xi.  Sir  D.  Barry,  Experimental  researches 
on  the  influence  of  atmospheric  pressure  on  the 
flow  of  blood  in  the  veins  and  on  absorption,  Lond. 
1826.  On  the  application  of  the  barometer  to  the 
study  of  the  circulation,  Annal.  d.  Sc.  Nat.  x. 
Carus,  Remarks  on  the  above  theories,  Meckel's 
Archiv.  iv.  1818,  p.  413.  Ellerby,  Davies,  and 
Serle,  Lancet,  xi.  p.  606,  &c.  Poiseuille,  in  Ma- 
gendie's Journal,  x.  Arnott's  Physics.  H.  Marx, 
Diatribe  anat.  phys.  de  structura  et  vita  venarum, 
Carlsruh.  1819.  Refutation  of  the  theories  of 
Carson  and  Barry,  Edin.  Journ.  of  Med.  Sc.  ii. 
462.  Wedemeyer  on  the  same,  Edin.  Med.  and 
Surg.  Journ.  xxxii.  p.  86.  Macfadyen  on  the  cir- 
culation, in  same  work,  xxii.  271.  Wilson  Philip 
on  the  effect  of  derivation  in  promoting  the  flow  of 
blood  in  the  heart,  Inquiry,  p.  9,  &c.  Lugenbuhkr, 
De  motu  sanguinis  per  venas,  1815.  J.  W.  Tur- 
ner's Remarks  on  the  same  subject,  Med.  Chirurg. 
Trans,  of  Edin.  vol.  iii.  Magendie,  Influence  of 
Respiration  on  the  motion  of  the  blood  in  the 
arteries,  Journal,  t.  i.  Bourdon,  Rech.  sur  le 
mecanisme  de  la  respiration  et  sur  la  circulation 
du  sang,  Paris,  1820.  Defermon  on  the  mutual 
dependence  of  respiration  and  circulation,  Ann.  d. 
Sc.  Nat.  xiii.  425.  Hales  on  the  force  of  the  blood 
in  the  veins,  Med.  Statics,  vol.  ii.  p.  27  &  31. 
Flourens,  Sur  la  force  de  contraction  des  prin- 
cipales  veines  de  la  Grenouille,  Ann.  d.  Sc.  Nat. 
xxviii.  65.  Nic.  Oudemann,  De  venarum,  praecipue 
mesaraicarum  fabrica  et  actione,  Groning.  1794. 
Kellie  on  the  circulation  in  the  head,  Edin.  Med. 
Chirurg.  Trans,  vol.  i.  Carson  on  the  same,  Edin. 
Med.  and  Surg.  Journ.  vol.  xxi.  p.  252. 

Capillaries  and  small  vessels. — Doellinger,  Munich 
Transactions,  vol.  vii.  and  Journal  des  Progres. 
Do.  Was  is  Absonderung,  &c.  ?  Wiirtzburg,  1819. 
Gruithuysen,  Beitrage  zur  Physiognosie  und  Eau- 
tognosie,  &c.  Miinchen,  1812.  Organozoonomie, 
&c.  Miinchen,  1811.  Kaltenbrunner,  Experimenta 
circa  statum  sanguinis  in  inflammatione,  Stutt. 
1826.  Leuret,  on  the  same,  Journal  des  Progres. 
Whytt  on  the  circulation  in  the  small  vessels, 
Works,  p.  211.  Schultx,  Journal  Complement, 
vol.  19;  also  Der  Lebensprocess  im  Blute,  &c. 
Berlin,  1822.  R.  Wagner,  Zur  Vergleich.  Phy- 
siologie  des  Blutes,  Leipzig,  1833.  Baumgartner, 
Beobacht.  liber  die  Nerven  und  das  Blut,  &c. 
Freiburg.  1833.  Oesterreicher,  Versuch  einer  Dar- 
stellung  der  Lehre  des  Kreislaufs,  Nurnberg.  1830. 
Marshall  Hall,  Essay  on  the  circulation  of  the  blood, 
8vo.  Lond.  1831.  J.  Mutter,  capill.  circul.  in  the 
liver  of  the  Salamander,  Meckel's  Archiv,  xvi. 
1829,  p.  182.  Wedemeyer,  Additions  to  his  work, 
Meckel's  Archiv,  1828,  p.  337.  J.  W.  Earle  on 
the  irritability  of  the  small  vessels,  Med.  Gaz. 
1834-35,  No.  29,  p.  70.  Kaltenbrunner,  Magendie's 
Journ.  viii.  John  Evelyn  on  the  passage  of  blood 
from  arteries  to  veins  in  quadrupeds,  Phil.  Trans. 
xxiii.  1702,  p.  1177.  Molyneux  in  another  volume 
of  the  same.  Jas.  Black,  Essay  on  the  capillary 
circulation,  London,  1825.  Alisons  Outlines  of 
Physiol.  Appendix  to  2nd  edition,  1836.  Hunter 
on  the  blood  and  inflammation.  Thomson's  Lec- 
tures on  inflammation,  Edin.  1813.  Burns  on 


inflammation.  Gendrin,  Hist.  anat.  des  inflam- 
mations, Paris,  1825.  Reuss,  Electrical  theory  of 
the  capill.  circulation,  Edin.  Med.  and  Surg.  Journ. 
Meyen,  De  primis  vitae  phaenom.  et  de  circulatione 
sanguinis  in  parenchymate,  Bcrol.  1826.  Kruger, 
Diss.  de  theoriae  physics  tubulorum  capillar.  ad  corp. 
human,  applicatione,  Halae  Magd.  1742. 

Influence  of  the  nerves  on  the  circulation. —  Trevi- 
ranus,  Vermischte  schriften,  i.  p.  99.  Home, 
Philos.  Trans.  1814.  Flourens,  Action  of  the  spi- 
nal marrow  on  the  circulation,  Ann.  d.  Sc.  Nat. 
viii.  271.  Krimer,  Physiolog.  Untersuchungen. 
Leipzig.  1820.  Legallois,  Exper.  sur  le  principe 
de  la  vie,  Paris,  1812.  W.  Philip,  Laws  of  the 
vital  functions.  Clift  on  the  heart,  Philos.  Trans. 
Bracket,  Exper.  sur  les  fonctions  des  nerfs  sym- 
pathiques,  Paris.  Milne  Edwards  Sf  Vavasseur, 
Ann.  d.  Sc.  Nat.  vol.  ix.  p. 329.  Influence  of  the 
cervical  ganglia  and  their  nerves  on  the  action  of 
the  heart. 

(Allen  Thomson.) 

CIRRHOPODA;  Cirripedia;  Cirripeds  ; 
(xt£§o?  and  woD?,  cirrus  and  pes,  from  the  curl- 
like  form  which  the  coiled  feet  or  arms  present. 
Fr.  Cirripedes.  Ger.  Rankenfuesser.')  A  class 
of  invertebrate  animals,  composed  chiefly  of 
the  barnacles  and  acorn-shells.  They  are  re- 
lated in  some  points  of  structure  with  the  annu- 
lated  or  diploneurose  animals,  particularly  with 
Crustacea ;  in  other  points  they  resemble  Ace- 
phala  (Conchifera).  All  are  marine  and  fixed. 
The  soft  parts  are,  for  the  most  part,  encased 
in  a  multivalve  shell.  The  body  is  somewhat 
conical  in  form,  tumid,  and  bent  inwards  at 
the  oral  extremity,  tapering  towards  the  oppo- 
site extremity,  where  it  terminates  in  a  long 
pointed  tube.  Placed  along  the  abdominal 
surface,  there  are  two  rows  of  fleshy  lobes, 
(six  on  either  side,)  each  having  two  long 
horny  processes,  jointed  and  ciliated.  In  some 
species,  these  constitute  the  chief  bulk  of  the 
whole  animal.  The  head  is  indistinctly  de- 
nned, and  has  neither  eyes  nor  tentacles; 
mouth  with  lips,  and  three  pairs  of  horny 
jaws ;  anus  at  the  base  of  the  tubular  process. 
Respiration  is  effected  by  branchiae,  which,  in 
some  species,  are  filamentary,  in  others  foli- 
ated. Mantle  membranous,  sacculated,  pro- 
vided with  a  slit-like  opening  for  the  passage 
of  the  arms,  &c.  Between  each  two  pairs  of 
arms,  the  abdominal  surface  is  marked  by  six 
slight  depressions,  which  may  be  regarded  as 
an  approach  towards  complete  articulation. 

The  animals  thus  characterized  have  had  dif- 
ferent places  assigned  to  them  in  the  various 
systematic  arrangements  of  modern  zoologists. 
Cuvier  formed  of  them  the  sixth  and  last  class 
of  his  Mollusca.  Lamarck  was  at  one  period 
inclined  to  place  them  amongst  the  Crustacea, 
but  latterly  he  constituted  for  them  a  distinct 
class,  and  placed  it  between  Annelida  and 
Conchifera ;  still,  however,  regarding  them  as 
more  closely  allied  to  Crustacea  than  to  any 
other  class ;  "  for,"  as  he  remarked,  "  they 
have  the  nervous  system  of  Crustacea,  they 
have  jaws  analogous  to  those  of  the  animals 
of  that  class,  and  their  tentacle-like  arms 
resemble  the  antennae  of  the  lobsters."*  Bur- 

*  An.  sans  Vertebres,  v.  377. 
2  Y  2 


684 


CIRRHOPODA. 


meister  also  places  them  amongst  the  Crus- 
tacea. De  Blainville  arranges  them,  under  the 
name  of  Nematopoda,  as  a  class  of  his  subtype 
of  the  Mollusca  —  Mollusc-articulata  ;  the 
other  class  of  the  subtype  being  formed  of 
the  Chitons  (Polyplakiphora).  He  regards 
them  as  Crustaceous  Mollusca,  but  admits 
that  they  seem  to  form  a  transition  group 
uniting  the  Crustacea  with  the  Annelida.  M. 
St.  Ange,*  however,  would  rather  class  them 
with  the  Annelida,  on  account  of  the  closer 
resemblance  which  the  arrangement  of  their 
nervous  system  bears  to  that  of  these  animals. 
Professor  Wagner  does  not  doubt  that  they  are 
really  articulated  animals,  but  he  would  rather 
place  them  in  a  distinct  class  between  the 
Mollusca  and  Articulata.  Setting  aside  their 
nervous  system,  M.  Serres  sees,  in  the  other 
parts  of  their  structure,  points  enough  to  in- 
duce him  to  arrange  them  with  the  Mollusca. 
The  same  views  are  entertained  by  Wiegmann, 
Goldfuss,  and  others.  Dr.  Leach  regarded 
them  as  truly  annulose  animals.  Dr.  Grant 
(who  calls  them  "  entomoid  animals  enclosed 
in  shells")  places  them  amongst  the  Articulata, 
or  diploneurose  animals,  between  Rotifera  and 
Annelida,  making  of  them  a  distinct  class,  but 
admitting  their  great  resemblance  in  many 
points  to  the  entomostracous  Crustacea.  Mr. 
J.  V.  Thompson  (whose  admirable  researches 
on  the  development  of  the  Cirripeds  have 
thrown  a  new  interest  around  them)  holds  it  as 
proved  by  his  observations  that  the  Cirripeds 
do  not  constitute  a  distinct  class;  but  that  they 
are  naturally  and  closely  connected,  on  the  one 
hand,  with  the  Decapod  Crustacea,  through 
the  Balanids,  and,  on  the  other,  with  the 
Entomostraca,  through  the  Lepads;  further, 
that  they  have  no  relation  with  the  Testacea. 

All  the  known  Cirripeds  may  be  naturally 
grouped  into  two  families,  one  pedunculated, 
the  other  sessile.  The  former  includes  all  the 
barnacles,  properly  so  called;  the  latter,  the 
acorn-shells.  The  barnacle  family  have  had 
the  name  of  Campylosomata  applied  to  them 
by  Dr.  Leach,  who  calls  the  other  family 
Acamtosomata :  but  we  shall  use  De  Blain- 
ville's  synonyms  of  Lepadicea  and  Balanidea. 
The  following  are  the  names  of  the  genera 
generally  used  at  present :  — 

I.  LEPADICEA. 

1.  Otion.     2.  Cineras.     3.  Anatifa.     4. 
Pollicipes.     5.  Scalpellum. 

II.  BALANIDEA. 

1.  Balanus.      2.  Ochthosia.      3.  Conia. 

4.  Creusia.      5.  Clisia.     6.  Pyrgoma. 

7.  Acasta.     8.  Coronula.     9.  Tubici- 

nella.  10.  Chelonobia. 
External  coverings  and  organs  of  support. — 
There  are  three  principal  modifications  of  the 
tegumentary  organs  in  this  class.  The  first  is 
that  seen  in  Anatifa,  in  which  it  assumes  the 
form  of  calcareous  plates,  united  by  horny 
ligament,  and  attached  to  a  cartilaginous  pe- 
duncle. The  second  form  is  that  common  to 
all  the  Balanids — a  calcareous  cone,  composed 
of  separable  pieces,  sessile,  and  provided  with 

*  Mem.  sur  les  Cirripedes.     Paris,  1835. 


Fig.  332. 


an  opercule  of  shelly  plates.  The  third  form 
is  a  general  cartilaginous  covering,  sometimes 
strengthened  by  small  calcareous  plates. 

The  shells  of  the  Cirripeds  are  similar  in 
general  appearance  to  those  of  many  Acepha- 
lous Mollusca.   They  are  most  fully  developed 
in  Anatifa,  which  has  five  separate  plates,  four 
placed   laterally   in    pairs,    and  one  median. 
One  pair  is  conside- 
rably larger  than  the 
other  (c,  Jig.  332) ;  it 
covers  all  the  anterior 
part  of  the  animal,  and 
the  greater  part  of  the 
internal  organs.    The 
bases  of  these  shells 
are  attached  to  the  car- 
tilaginous   peduncle  ; 
the    lower    halves    of 
their    anterior     edges 
form  part  of  the  mar- 
gin   of    the    slit-like 
opening  through  which 
the  arms  are  protruded 
f/,g,./^332).     The 
inferior  pair  of  shells 
(d)  are  of  a  triangular 
form ;  the  smallest  side 
completes  the  margin 
of   the    brachial   ori- 
fice ;  another  side  is  united  by  ligament  to  the 
upper  valve;  the  third  is  connected  with  its 
fellow  by  the  common  intervalvular  ligament. 
The  median  piece  (e)  covers  the  dorsal  aspect 
of  the  animal.     It  has  an  elongated  lanceolate 
shape,    curved   and  grooved    internally.      Its 
upper  point  only  is  inserted  into  the  peduncle. 
Its  margins  are  imbedded  in  the  intervalvular 
ligament.    This  piece  may  be  compared  to  the 
unpaired  valve  of  the  shell  of  Pholas :  it  oc- 
cupies nearly  the  same  situation.    The  surface 
of  these  shells  is  generally  denuded  of  epi- 
dermis, excepting  just  around  their  margins. 
All  three  are  strongly  and  regularly  marked 
with  lines  of  growth,  from  which  it  is  seen 
that  the  two  pairs  of  lateral  valves  increase  in 
size,   chiefly,  by  additions  to  their  margins, 
which  look  towards  one  another ;  so  that  the 
parts  first  formed  are,  in  the  adult  animal,  re- 
moved to  the  greatest  possible  distance  from 
one  another.    In  the  upper  valve,  the  umbo  or 
centre  of  growth  is  situated  in  the  anterior- 
superior  angle,  close  to  the  termination  of  the 
peduncle;  in  the  lower,  it  is  situated  in  the 
anterior-inferior  angle;  and  in  the  dorsal  valve, 
in  the  point  next  to  the  peduncle.     All  the 
shells  are  thin,  diaphanous,  of  nearly  the  same 
thickness  throughout,   yet  much   less  fragile 
than    shells  of  Acephalous   Mollusca  which 
otherwise  resemble  them.      It  has  been  re- 
marked by  Burmeister  that  the  shells  of  Cir- 
ripeds resemble  those  of  crustaceous  animals 
more  than  those  of  Molluscs  :  to  us  it  appears 
that  |hey  have  a  greater  degree  of  density,  and 
a  more  compact  crystalline  structure  than  are 
commonly  met  with  in  Crabs ;  and  that  their 
well-marked  lines  of  growth  give  them  a  closer 
resemblance  to  shells  of  acephalous  mollusca. 
In  some  genera,  as  Pollicipes,  in  addition  to 


CIRRIIOPODA. 


685 


the  five  valves  just  described,  there  are  other 
eight  smaller  calcareous  plates  arranged  around 
the  junction  of  the  peduncle  with  the  shells. 

The  shells  of  the  Balanids  present  several 
striking  peculiarities  of  structure,  and,  in  their 
mode  of  growth,  offer  to  the  physiologist  an 
interesting  subject  for  investigation.  They 
form  truncated  cones,  the  bases  of  which, 
without  the  intervention  of  peduncles,  are  fixed 
to  rocks,  floating  wood,  integuments  of  marine 
animals,  &c.  These  cones  are  composed  of 
several  pieces,  closely  cemented  together  so  as 
to  admit  of  no  motion  between  them,  excepting 
during  the  process  of  enlargement  of  the  shell. 
In  the  common  acorn-shells  (Jig.  333),  which 

cover  our  litto- 

Fig.  333.  ral    rocks    and 

the  bottoms  of 
ships,  there  are 
seven  of  these 
pieces,  six  form- 
ing the  walls, 
and  one  dis- 
coid, forming 
the  base.  The 
outer  surface  of 
the  parietal 
valves  is  mark- 
ed by  the  lines 
of  growth  in 
such  a  manner 

as  to  give  it  the  appearance  of  being  com- 
posed of  twelve  pieces.  These  may  be  termed 
compartments.  They  are  all  conical.  Six  of 
them  have  their  bases  applied  to  the  common 
base  of  the  shell,  and  the  other  six  are  inserted 
between  these,  with  their  apices  towards  the 
common  base.  The  first  six  we  shall  refer  to 
under  the  name  of  thejirst  series  of  compart- 
ments (a,  a,  fig.  333)  ;  the  other  six  constitute 
the  second  series  (6,  b,  Jig.  333).  The  opening 
in  the  summit  of  the  cone  is  closed  by  an 
opercule  composed  of  four  shelly  pieces  so 
arranged  as  to  leave  a  longitudinal  fissure  be- 
tween them,  through  which  the  arms  are  pro- 
truded (c,  Jig.  333).  The  two  series  of  com- 
partments differ  much  from  one  another  in 
their  external  aspect,  owing  to  the  differences 
in  the  directions  and  appearances  of  the  lines 
of  growth.  The  second  series  have  a  smoother 
surface,  and  are  marked  with  very  delicate 
lines,  both  longitudinal  and  transverse ;  they 
are  also  less  prominent  than  the  first  series. 
The  lines  on  the  first  series  are  chiefly  trans- 
verse, and  correspond  with  the  outline  of  the 
base.  On  the  internal  surface  of  the  walls 
there  are  six  deep  grooves,  in  the  bottoms  of 
which  are  seen  the  openings  into  certain  cham- 
bers, constituting  a  sort  of  diploe  of  the  valves, 
hereafter  to  be  described.  These  grooves  run 
from  the  summit  to  the  base  of  the  shell,  and 
are  the  internal  edges  of  the  sutures  of  the  six 
parietal  valves.  Around  the  internal  margin 
of  the  common  base  there  is  a  series  of  holes 
opening  into  certain  tubes  that  terminate  on 
the  outer  margin  of  the  shell.  When  all  the 
valves  are  separated  at  the  sutures,  it  is  found 
that  each  of  four  of  the  six  compartments 
of  the  first  series,  as  they  appear  externally, 


has  attached  to  its  dorsal  margin  one  of  the 
second  series,  arid  that  the  union  between  these 
two  is  exceedingly  intimate,  in  fact  that  they 
form  one  piece,  notwithstanding  their  apparent 
division  externally.  Two  of  the  second  series 
of  compartments  are  attached  to  the  anterior 
valve,  while  the  dorsal  valve  has  none.  The 
anteal  margins  of  the  lateral  valves  and  both 
margins  of  the  dorsal  valve  are  marked  by 
transverse  depressions  corresponding  to  the 
numerous  partitions  of  the  chambered  com- 
partments which  are  fitted  into  them ;  and, 
externally,  each  has  a  projecting  margin.  To 
the  upper  part  of  the  inner  surface  of  each  valve 
there  is  attached  a  laminated  process,  form- 
ing part  of  a  circle  of  calcareous  plates  which 
gives  support  to  some  parts  of  the  mantle. 

The  internal  structure  of  these  shells  pre- 
sents some  peculiar  features.  They  all  contain 
numerous  tubes  and  cavities,  regularly  ar- 
ranged, and  forming  a  sort  of  diploe.  The 
suture-holes  mentioned  above  open  each  into 
a  separate  canal,  chamber,  or  tube.  Those 
which  occur  in  rows  on  the  walls  of  the  cone 
lead  to  small  chambers  within  the  second  series 
of  compartments,  running  parallel  with  the 
general  base,  and  separated  from  one  another 
by  delicately-formed  partitions,  each  of  whicli 
is  deeply  grooved  on  both  sides.  The  par- 
titions are  placed  at  equal  distances,  and  their 
grooves  are  most  regularly  formed.  The  whole 
presents  one  of  the  most  beautiful  and  delicate 
pieces  of  structure  with  which  we  are  ac- 
quainted in  the  whole  range  of  extravascular 
skeletons.  These  are  from  thirteen  to  fifteen 
on  either  side  of  each  partition.  Fig.  334  repre- 
sents a  perpendicular  section 
of  a  few  of  these  grooved  par- 
titions considerably  magnified. 
Fig.  335  represents  a  horizontal 
section  of  one  of  the  six  valves. 
The  holes  forming  the  sutures 
are  at  a.  The  grooved  floor 
of  one  of  the  chambers  of  the 
piece  is  be- 

Fig.  335.  tween   a,    d, 

and  c.  d,  c 
is  the  outer 
wall  of  the 
compartment 
of  the  se- 
cond series,  a,  b  is  a  section  of  that  part  of 
the  valve  which  appears  outside  as  a  compart- 
ment of  the  first  series.  Its  diploe'  is  com- 
posed of  tubes,  running  from  the  apex  to  the 
base,  gradually  enlarging  below.  Horizontal 
sections  of  those  tubes  shew  them  to  be  of  an 
ovate  form,  tapering  inwardly  (Jig.  336).  They 
are  placed  nearer 

Fig.  336.  the  outer  wall  than 

the  inner.  The 
spaces  intervening 
between  the  taper- 
ing sides  of  the 
tubes  are  marked  with  lines  of  growth,  shew- 
ing a  gradual  filling  up  of  the  tubes  from 
within  outwards;  and  also  the  previous  ex- 
istence of  furrows  or  grooves  on  the  surfaces 
of  the  partitions  between  the  tubes.  These 


Fig.  334. 


086 


CIRRHOPODA. 


Fig.  338. 


grooves  are  very  strongly  marked  in  some  spe- 
cies, as  in  Balanus  Spinosus  (Jig.  337),  where 
the  tubes  are  large,  and 
Fig.  337.  the  walls  comparatively 
thin.  In  all  they  run  in 
straight  diverging  lines 
from  the  apices  of  the 
compartments  to  their  bases.  There  they  open 
close  to  the  margin  of  the  general  base.  In 
most  species,  however,  their  orifices  are,  in 
part,  filled  up  by  an  extension  of  the  base  (a, 
Jig.  338).  In  some  small  species,  the  tubes  of 
which  are  wider  than  those  of  larger  ones, 
there  is  hardly  any  opening 
discoverable  externally,  or  at 
most  a  very  narrow  fissure  just 
around  the  margin.  Very  near 
their  terminations  on  the  mar- 
gin, these  tubes  of  the  diploe 
are  joined  by  the  very  short 
canals  which  proceed  from 
the  inner  circumference  of  the 
base  (b,  Jig.  338),  and  it  is  at 
their  junction  that  the  grooves 
in  the  walls  of  the  partitions  are  most  obvious. 
These  two  sets  of  tubes  communicate  freely  all 
around  the  margin  with  the  diploe  of  the  base. 
All  the  Balanids — with  the  exception  of  the 
Coronules — have  calcareous  bases.  The  struc- 
ture of  the  base  differs  from  that  of  the  walls 
in  being  composed  internally  of  large  oval 
cells  irregularly  arranged.  These  cells  seem 
to  communicate  freely  with  one  another  and 
with  the  tubes  of  the  valves.  The  Coronules 
have  no  base  :  their  soft  parts  are  in  immediate 
contact  with  the  integuments  of  the  living 
animals  in  which  they  are  generally  imbedded. 
The  form  and  arrangement  of  the  opercule 
vary.  There  are  generally  four  triangular 
valves,  two  larger  than  the  others,  all  deeply 
grooved  on  their  upper  surfaces  by  the  lines 
of  growth.  These  valves  cover  more  or  less 
completely  the  soft  parts  beneath,  to  which 
they  are  attached,  so  as  to  be  very  moveable 
one  upon  the  other,  and  to  admit  of  the  pas- 
sage of  the  feet  through  the  slit  that  exists  be- 
tween the  two  pairs.  In  some  of  the  coronules, 
the  greater  part  of  the  opercule  is  soft.  Coro- 
nula  diadema  has  two  small  shelly  plates  in  its 
opercule. 

Keeping  in  view  the  complex  but  beautiful 
structure  just  described,  it  is  not  difficult  to 
determine  how  the  whole  shell  increases  in 
size.  It  is  obvious  that  the  parietal  compart- 
ments of  the  first  series  are  enlarged  by  addi- 
tions to  their  basilar  edges  and  internal  surface, 
and  that  thus  the  whole  cone  is  lengthened, 
and  consequently  widened  at  its  base;  but, 
in  all  the  species,  it  is  also  widened  above ; 
and,  as  the  summits  of  the  first  series  of  com- 
partments are,  evidently,  not  at  all,  or,  at  most, 
very  slightly,  abraded  by  the  friction  of  the 
opercule,  it  is  certain  that  the  apices  of  these 
compartments — originally  very  closely  approx- 
imated— must  be  moved  outwards  and  sepa- 
rated from  one  another  by  the  gradual  increase 
in  breadth  of  the  intervening  wedge-like  com- 
partments of  the  second  series.  This  process 
implies  the  insertion  of  soft  parts  endowed 


with  vascular  action  between  the  valves  so  as 
to  admit  of  lateral  additions  being  made  to 
the  second  set  of  compartments.  There  can 
be  no  question  that  these  soft  parts  (foliated 
processes  of  the  mantle)  pass  into  the  sutures 
along  their  whole  length,  and  deposit  the 
shelly  matter  on  the  edges  of  the  partitions 
forming  the  chambered  structure  of  the  se- 
cond series  of  compartments ;  each  valve,  with 
the  exception  of  the  dorsal  one,  is  thus  added 
to  in  breadth;  and  as  the  distance  between 
the  original  valves  is  enlarged,  and  the  whole 
shell  lengthened,  new  chambers  are  formed 
below.  Of  course,  as  the  cone  is  lengthened, 
its  base  is  widened;  and  this  is  effected  by 
the  excretion  of  shelly  matter  from  such  parts 
of  the  mantle  as  can  easily  pass  through  the 
numerous  holes  placed  around  the  inner  cir- 
cumference of  the  base.  The  valves  of  the 
opercule  are  imbedded  in  the  margins  of  the 
mantle  between  the  epidermis  and  true  skin, 
and  are  increased  by  marginal  additions  in  the 
same  way  as  the  shells  of  molluscs. 

The  mode  of  growth  of  these  shells  engaged 
the  attention  of  Cuvier,  who  concluded  that  an 
addition  to  the  sides  of  the  valves  could  take 
place  only  in  an  early  age ;  for  it  appeared  to 
him  that  they  are,  in  a  more  advanced  stage, 
so  firmly  cemented  together  as  not  to  admit 
of  separation.  In  large  species,  however,  we 
find  that  the  valves  are  easily  separated  at  the 
sutures,  and  that  the  calcareous  matter  along 
the  sides  of  the  sutures  is  loosely  aggregated ; 
so  that,  to  us,  there  seems  to  be  no  impro- 
bability in  the  supposition  that  in  the  living 
animal  the  prolongations  of  the  mantle  pass 
between  the  terminations  of  the  minute  tubu- 
lar processes  of  the  second  series  of  compart- 
ments, and  the  corresponding  depressions  in 
the  edges  of  the  first  series  already  noticed. 
There  is  no  indication,  we  think,  of  each  of 
the  valves  being  "  detached  from  its  neighbour 
only  at  certain  times  that  it  may  receive  addi- 
tional calcareous  matter  along  its  sides,"  as 
Brugieres  and  Cuvier  imagined.  The  process 
of  growth  seems  to  be  carried  on  in  uniform 
progression  until  adult  age.  So  puzzling  did 
the  problem  of  the  mode  of  growth  in  these 
shells  appear  to  Dufresne,  that  he  concluded 
that,  like  crabs,  the  Balanid  casts  its  old  shell, 
and  forms  a  new  one,  as  it  increases  in  size.* 
Cuvier  remarked  that,  "  while  the  mode  of 
growth  of  the  shells  of  the  Mollusca  resembles 
that  of  simple  teeth,  the  organization  and  in- 
crease of  the  shells  of  balanids  may  be  com- 
pared to  that  of  certain  compound  teeth,  par- 
ticularly those  of  diodons  and  tetrodons." 

Tubicinella,  a  parasite  of  the  Whale,  differs 
much  from  the  other  balanids  in  the  formation 
of  its  shell.  The  widest  part  of  its  six-valved 
cone  is  superior;  the  whole  surface  is  strongly 
ribbed,  and  marked  with  transverse  lines  of 
growth ;  and  it  appears  that  the  additions  to 
the  cone  are  made  on  the  upper  margin  ;  this 
margin  is  surrounded  internally  by  a  thick  and 
fleshy  production  of  the  mantle,  which  is  never 
altogether  covered  by  the  opercule.  The  base 

*  Ann.  du  Mus.  i.  467. 


CIRRHOPODA. 


687 


is  open,  and  of  little  less  diameter  than  the 
upper  part,  which  led  Dufresne  to  conclude 
that  the  animal  does  not  form  a  shell  until  it 
be  considerably  advanced  in  growth.  This 
seems  to  be  very  probable,  as  the  base  is  im- 
bedded deeply  in  the  integument  of  the  Whale, 
and  descends  lower  the  more  it  increases  in 
size,  so  as  to  leave  only  the  summit  of  the 
shell  visible.  The  imbedded  portion  is  gene- 
rally deeply  coloured  by  the  tegumentary  pig- 
ment of  the  Whale.  In  coronula,  which  also 
inhabits  the  backs  of  Whales,  but  has  the  same 
general  structure  of  shell  as  the  majority  of 
Balanids,  the  valves  are  deeply  partitioned, 
and  provided  with  toothed  processes,  fitted  to 
fix  the  animal  in  its  site. 

The  only  other  calcareous  coverings  that  re- 
main to  be  noticed  are  the  rudimentary  valves 
in  Otion  and  Cineras,  animals  that  bear  a 
general  resemblance  in  form  to  Anatija,  but 
which  are  covered  chiefly  by  a  semicartila- 
ginous  tunic.  There  are  two  small  valves  in 
Otion,  which  are  attached  to  the  anterior  as- 
pect just  above  the  brachial  orifice.  In  Cine- 
ras they  are  five  in  number,  two  in  the  same 
situation  as  those  of  Otion,  two  along  the  ter- 
minal margin  of  the  outer  tunic,  and  one 
unpaired  along  the  dorsal  aspect.  These  are 
imbedded  by  their  margins  in  the  semi-carti- 
laginous tunic,  and  seem  to  be  formed  by  it ; 
calcareous  matter  being  added  to  their  margins 
in  successive  layers. 

The  ligamentous  membrane,  by  which  the 
valves  in  Anatifa  are  connected  one  with  the 
other  and  with  the  peduncle,  is  strong  but 
pliant.  It  is  an  extension  of  the  outer  cover- 
ing of  the  peduncle.  At  the  brachial  orifice, 
it  is  reflected  inwards  to  join  the  mantle.  In 
addition  to  this,  each  valve  has  a  membrane 
of  its  own,  which  closely  invests  its  inner  sur- 
face, and  is  not  continuous  with  those  of  the 
other  valves.  The  peduncle  of  this  and  the 
allied  genera  may  be  considered  as  a  kind  of 
developed  ligament.  If  we  regard  the  upper 
pair  of  valves  as  analogous  to  the  valves  of 
Acephalous  Mollusca,  the  peduncle  is  found 
to  be  attached  to  them  at  points  corresponding 
to  the  situation  of  the  ligament  in  those  shells. 
This  organ  is  sometimes  of  great  size.  In  the 
British  seas  it  occasionally  occurs  two  feet  in 
length.  Its  epidermis  is  generally  rough, 
wrinkled  transversely,  coriaceous,  and  elastic : 
Otion,  however,  has  it  very  smooth  and  stiff, 
nearly  cartilaginous,  diaphanous.  In  some 
species  it  is  so  elastic  as  to  admit  of  exten- 
sive lateral  motion,  and  much  elongation  and 
contraction.  These  movements  are  effected  by 
a  layer  of  strong  muscular  tissue  beneath  the 
skin,  within  which  there  is  a  large  organ, 
granular  in  its  structure,  regarded  by  some 
anatomists  as  the  ovary.  Burmeister  is  of 
opinion  that  the  peduncle  is  merely  an  organ 
of  support  :  and  he  suggests  that  the  granular 
parenchymatous  mass,  which  fills  its  interior, 
is  destined  solely  for  its  own  nutrition,  which  he 
seems  to  think  is  independent  of  the  other  parts 
of  the  animal.  In  most  species,  it  is  by  its  epider- 
mis that  the  peduncle  adheres .  The  peduncle  pre- 


sents still  other  varieties  than  those  just  mention- 
ed. Po/licipcx  villusus  has  it  covered  partly  with 
imbricated  scales,  and  partly  with  a  hairy  coat ; 
and  Pollicipes  quudrivalvis  has  its  valves  wholly 
encased  in  a  large  prolongation  of  the  pe- 
duncle, which,  on  its  upper  surface,  bears 
four  valves  arranged  nearly  in  the  same  way 
as  those  of  the  opercule  of  the  Balanids.  The 
base  of  Coronula  is  closed  by  a  strong  fibrous 
membrane  connected  with  the  body  of  the 
animal  only  by  a  process  of  the  epidermis. 
It  is  regarded  by  Burmeister  as  the  analogue 
of  the  peduncle  of  the  Lepads. 

The  cartilaginous  tunic  of  Otion  Cuvieri, 
at  its  summit,  is  enlarged  into  two  large  auri- 
form appendages,  hollow,  having  a  crescentic 
orifice  externally,  and  internally  commu- 
nicating with  the  visceral  cavity  of  the  animal ; 
no  organ  is  discoverable  within  them,  but 
their  cavities  receive  the  terminations  of  a  duct, 
which  descends  on  the  dorsal  aspect  of  the 
body,  in  the  groove  of  the  dorsal  valve,  from 
the  peduncle. 

Of  the  mantle,  as  one  of  the  tegumentary 
organs  of  the  Cirripeds,  little  more  need  be 
said,  than  that  it  is  generally  a  very  thin  trans- 
parent membranous  sac,  surrounding  the  vis- 
ceral mass,  open  only  at  the  brachial  orifice, 
where  it  joins  the  epidermis  and  intervalvular 
ligament,  and  is  reflected  so  as  to  form  an 
inner  lining  for  the  visceral  cavity.  It  has 
neither  fringes  of  filaments,  nor  foliated  pro- 
cesses. M.  St.  Ange  describes  another  tunic 
of  the  visceral  mass,  which,  he  says,  is  con- 
tinuous with  the  horny  covering  of  the  arms. 

Locomotion. — Their  base  being  permanently 
fixed,  the  principal  motions  of  the  Cirripeds 
are  those  of  the  arms,  which  seem  to  be  sub- 
servient at  once  to  the  respiratory  and  to  the 
digestive  functions.  But,  as  has  just  been 
mentioned  above,  the  peduncle  of  Anatifa  and 
other  allied  genera  is  moved  both  laterally  and 
in  the  way  of  contraction  and  extension,  and 
the  valves,  in  the  same  animals,  are  so  moved 
as  to  open  and  close  the  brachial  orifice. '  The 
motions  of  the  arms  are,  in  many  species, 
very  rapid,  and  are  performed  with  great  re- 
gularity ;  proving  the  existence  of  a  complete 
muscular  apparatus  both  at  their  bases  and 
within  their  numerous  joints ;  but  the  parts  are 
too  minute  to  admit  of  a  satisfactory  examina- 
tion being  made  of  their  structure.  The  Lepads 
have  a  strong  transverse  adductor  muscle  placed 
between  their  superior  valves,  just  above  the 
brachial  orifice  (a,  fig.  340) ;  this  muscle  seems 
to  be  every  way  analogous  to  the  same  organ 
in  Acephala.  Its  action  closes  the  brachial 
slit  very  accurately ;  while  its  relaxation  admits 
of  its  being  opened  by  the  advance  of  the 
arms  grouped  together  into  the  form  of  a  wedge. 
This  movement  of  the  arms  cannot  be  per- 
formed without  the  whole  body  being  carried 
outwards ;  which  is  effected  apparently  by  the 
contraction  of  certain  delicate  muscular  fibres 
spread  over  the  mantle,  and  attached  around 
the  margin  of  the  orifice.  Cuvier  describes  a 
similar  set  of  fibres,  "  attached  to  the  mantle 
opposite  the  insertion  of  the  peduncle,  by 


688 


CIIIIIHOPODA. 


the  action  of  which  the  general  mass  of  the 
body  is  drawn  deeply  within  the  shell." 
This  we  have  failed  to  observe  in  the  species 
which  have  come  under  our  notice.  When 
the  arms  are  fully  exserted,  they  are  separated 
one  from  the  other,  fan-like.  This  motion  is 
probably  produced  by  a  muscular  expansion, 
described  by  M.  St.  Ange  as  covering  the 
visceral  mass  dorsally,  the  fibres  of  which  are 
grouped  into  six  bundles  on  either  side,  cor- 
responding to  the  arms.  The  same  observer 
describes  also  certain  tendons  which  he  found 
crossing  one  another  at  the  median  line  ;  these 
are  probably  connected  with  another  layer  of 
muscles,  expanded  over  the  dorsal  surface  of 
the  visceral  mass,  fitted  to  approximate  the 
arms  of  either  side  towards  one  another.  The 
muscles  of  the  jaws  cannot  be  satisfactorily 
examined  on  account  of  their  minuteness.  In 
the  Balanids,  the  valvular  opercule  is  moved 
by  a  set  of  muscles  attached  to  the  circle  of 
shelly  plates  that  surround  the  opening  of  the 
parietal  cone.  Its  adductors,  which  close  the 
aperture  with  great  force,  are  attached  to  the 
extremities  of  the  valves  on  either  side.  The 
visceral  mass  is,  in  the  Balanids,  fixed  to  the 
shell  by  three  muscular  bands,  partly  attached, 
around  the  mouth,  to  a  process  of  the  epider- 
mis, and  partly  spread  over  the  mantle. 

Mot'dity  and  Sensation. — The  nervous  sys- 
tem of  the  Cirripeds  consists  essentially  of  two 
nervous  cords  running  along  the  abdominal 
surface,  and  swelling  out  into  distinctly  formed 
ganglions,  at  intervals  corresponding  to  the 
feet-bearing  lobes.  The  first  pair  of  ganglions 
is  situated  above  the  oesophagus  (Jig.  339). 
They  are  united 
by  a  very  short 
nervous  cord. — 
From  this  supra- 
cesophageal  gan- 
glion and  the  u- 
niting  cord,  there 
arise  anteriorly 
three  or  four 
nerves,  which  are 
distributed  to  the 
musculRr  tunics. 
The  principal  ner- 
vous cords,  leav- 
ing the  first  gan- 
glion posteriorly, 
descend  to  encir- 
cle the  oesopha- 
gus. In  this 
course,  they  give 
off  branches  to 
the  salivary  glands  and  other  neighbouring 
parts,  and  particularly,  (as  M.  St.  Ange  has 
pointed  out,)  a  nerve  of  communication  with 
a  small  lateral  ganglion  (/c,  k,fig.  339)  on  either 
side,  situated  near  the  stomach  and  below  the 
salivary  organs.  This  is  connected  also  with 
the  second  pair  of  ganglions.  From  this  se- 
cond pair,  several  branches  arise,  some  of 
which  go  to  the  stomach,  and  two  to  the  first 
pair  of  arms.  The  other  arms  receive  only 
one  branch  each  («,  i),  which  is  divided  into 


Fig.  339. 


two,  one  for  each  of  the  jointed  processes. 
In  its  course  along  the  abdominal  surface, 
the  double  ganglionic  cord — the  centre  of  the 
nervous  system — lies  immediately  beneath  the 
skin,  between  the  bases  of  the  arms.  The 
fifth  and  the  sixth  pairs  of  ganglions  have  the 
appearance  of  being  closely  united.  The  tu- 
bular process,  which  terminates  the  anal  ex- 
tremity of  the  body  receives  two  nerves,  one 
from  each  of  those  going  to  the  sixth  pair  of 
arms.  Dr.  Grant  directs  our  attention  to  the 
fact  that  all  the  anterior  parts  of  this  system 
are  very  imperfectly  developed  compared  with 
the  posterior  parts,  and  with  the  same  parts 
in  other  articulated  animals,  which  have  their 
heads  free,  and  organs  of  sense  more  com- 
plete. 

The  sense  of  touch  is  the  only  one  enjoyed 
by  the  Cirripeds,  so  far  as  we  can  discover. 
The  ciliated  arms  of  some  of  the  species  are 
acutely  sensitive:  they  are  withdrawn  imme- 
diately on  being  touched  by  any  foreign  body, 
and  when  the  surrounding  fluid  is  unfit  for 
respiration.  Some  observers  have  also  re- 
marked that  they  shrink  from  a  strong  light 
brought  to  shine  upon  them  suddenly.  In 
the  adult  animals,  there  are  certainly  no 
organs  which  can  be  regarded  as  eyes;  but, 
according  to  Mr.  Thompson,  what  he  be- 
lieves to  be  the  free-moving  young  have  very 
well  developed  eyes,  like  those  of  some  crus- 
tacea. 

Some  of  the  littoral  Cirripeds,  when  left 
dry  at  ebb-tide,  seem  to  be  sensible  of  certain 
changes  being  produced  in  the  state  of  the  sur- 
rounding air  by  the  approach  of  a  living  being 
to  the  place  of  their  habitation.  We  have 
frequently  remarked,  on  drawing  near  a  spot 
densely  peopled  by  the  small  acorn-shells  that 
so  abundantly  cover  most  of  our  rocks  on  the 
sea-shore,  a  peculiar  faint  crackling  noise,  sud- 
denly produced,  gradually  subsiding  after  the 
lapse  of  a  few  seconds,  and  not  repeated 
until  a  movement  was  made  towards  another 
spot ;  and,  on  searching  for  the  cause  of  this 
singular  sound,  we  have  satisfied  ourselves 
that  it  is  uniformly  produced  by  the  sudden 
closing  of  the  opercules  of  the  Balanids,  which 
seem  generally  to  remain  open  in  ordinary  cir- 
cumstances. We  have  seen  this  motion  again 
and  again  follow  immediately  the  movement 
of  the  hand  towards  particular  spots,  (not, 
however,  nearer  the  shells  than  twelve  or  four- 
teen inches,)  so  that  we  could  not  but  con- 
clude that  the  animal  was  made  sensible, 
through  the  medium  of  the  air,  of  the  pre- 
sence of  some  foreign  body,  and,  fearing  dan- 
ger, closed  its  shell  for  self-protection  ;  just  as 
the  limpet,  warned  of  the  approach  of  hurtful 
agents  by  the  slightest  touch  of  its  shell,  fixes 
itself  more  securely  to  its  rocky  footing. 
What  the  nature  of  the  sense  is  which  is  thus 
used  by  the  Cirripeds,  we  have  no  means  of 
determining. 

Digestion. — The  minute  swimming  Crus- 
tacea appear  to  constitute  the  principal  food 
of  the  Cirripeds.  Sometimes,  however,  the 
shells  of  minute  Mollusca  are  found  in  their 


CIRRIIOPODA. 


C89 


Fig.  340. 


Fig.  341. 


stomachs,  and  Burmeister  once  found  part  of 
an  annelid  of  unknown  species.     The  food  is 
carried    towards   the  mouth  by  currents  pro- 
duced   by    the   rapid    motions   of    the  arms, 
which,  in  most  of  the 
species,  are  constantly 
spread  out  and  drawn 
in,    alternately,    with 
great  regularity.     The 
mouth  is  situated  just 
at   the  bottom  of  the 
funnel  -  shaped    cavity 
formed  by  the  spread 
arms  ( b,fig.  340).    In 
the  Lepads  its  position 
is  close  to  the  trans- 
verse adductor  muscle. 
Its  jaws  form  a  round 
protuberance,     which 
presents  itself  very  con- 
spicuously immediate- 
ly  on   separating   the 
arms.       It  might  al- 
most be  regarded  as  a 
head,  so  prominent  is 
it  (fig.  341,  />,&);  but  we  find  it 
composed   only   of    the  lip   and 
jaws,   with   their  muscles.      The 
lip  over-arches  the  jaws ;    it   is 
horny,  and  furnished  with  minute 
palpi.     There  are  three  pairs  of 
jaws.     The  first  or  outer  pair  are 
thin  horny  plates  of  an  oval  form, 
fringed  along  their  opposing  sides 
with  long  stiff  hairs.     The  other 
two  pairs  are  curved  and  deeply 
serrated  on  their  opposed  surfaces. 
The  middle  pair   bears   a  small 
palp   on    its  lateral  margin.     In 
some  species,  a  small  tongue  has 
been  found.     All  these  parts  bear  a  close  re- 
semblance to  the  same  organs  in  some  of  the 
Crustacea.    The  oesophagus  is  short ;  its  lining 
membrane   is    somewhat  horny,    stiff  enough 
permanently  to  distend  the  whole  canal ;  be- 
fore entering  the  stomach,  its  diameter  is  con- 
siderably enlarged.     It  receives   the  ducts  of 
two  salivary  glands.     The  stomach  (c,fig.  341) 
is  capacious;    externally,  it  presents  an  irre- 
gular  mamillated  surface,    studded    with  nu- 
merous small  prominences  closely  set,  which 
are  the  outer  surfaces  of  hepatic  cells,  formed  in 
a    layer   of    glandular  tissue  that  closely  in- 
vests the  walls  of  the  stomach.     These  cells 
communicate   directly  with  its  general  cavity 
(«,  fig.  342).     There  is  no  other  organ  that  can 
be  regarded   as  a  liver.*     Two  coscal  appen- 

*  Burmeister's  recent  researches  have  led  him 
to  conclude  that  both  the  Lepads  and  the  fialanids 
have  large  livers.  He  has  satisfied  himself  that 
the  organs,  regarded  by  Cuvier  as  the  ovaries, 
and  by  more  recent  authorities  as  the  testicles, 
communicate  by  ducts  with  the  upper  part  of  the 
intestinal  canal,  and  not  at  all  with  the  seminal 
vessels.  Hence  he  supposes  that  they  are  lobes 
of  the  liver  and  not  organs  of  reproduction.  Our 
own  dissections  lead  us  rather  to  agree  with 
Messrs.  Wacner  and  St.  Ango,  who  believe  them 
to  be  the  tesncles. 


d;i«;vs,    also    saccu-  Fig.  342. 

lated  internally,  and  ,^  _^> 

embossed  outwardly, 
are  attached  to  the 
stomach. 

The    intestine    is 
wide,  nearly  without 
convolutions,  and  ta- 
pering   towards    the 
anus  (d,eyfig.  341). 
In   the  Lepads    the 
stomach   is  situated 
in  that  part  of  the 
visceral    mass  near- 
est to  the  peduncle ; 
from  which  point  the 
intestine  runs  on  the  dorsal  aspect  of  the  body, 
and  terminates  in  the  anus  just  at  the  base  of 
the  articulated  tubular  process.     It  is  slightly 
dilated  near  the  anus.     The  walls  of  the  in- 
testine are  perfectly  smooth  and  free  from  folds 
and  duplications.     The  number  of  their  tunics 
cannot   be  satisfactorily  determined.     M.  St. 
Ange  has  described  a  singular  piece  of  struc- 
ture which  he  has  found  within  the  intestinal 
canal  of  certain  Anatifae  (c,  c,  fig.  342).     It  is 
a  kind  of  second  intestine,  which  floats  within 
the  cavity  of  the  one  just  described.     It  is 
nearly  equal  in  length  to  the  outer  canal.     Its 
upper  extremity  is  expanded,  funnel-shaped, 
with  edges  cut  into  fringed  processes  like  the 
mouths  of  the  Fallopian   tube   in   vertebrate 
animals.     These  processes  are  lodged   in  the 
cells  of  the  walls  of  the  stomach,  and  furnish 
the  only  means   of  attachment  to   the  outer 
walls  with  which  the  organ   is  provided.     It 
thence    tapers    towards    the    anal    extremity, 
where  it  is  pointed  and  closed.     Its  walls  are 
very  thin  and  delicate.     It  is  generally  filled 
with  alimentary  matter,  which  must  pass  from 
its  cavity  by  a  kind  of  rumination,  so  as  to 
enter  the  stomach  a  second  time. 

Circulation. — The  sanguiferous  system  of  the 
Cirripeds  has  not  yet  been  fully  investigated. 
Only  the  vessels  of  the  arms,  and  a  central 
canal,  situated  on  the  dorsal  aspect  of  the  body, 
have  been  discovered.  Poli  asserted  that  he 
saw  a  heart  pulsating  a  little  above  the  anus : 
but  it  does  not  appear  that  any  other  observer 
has  made  the  same  remark.  Burmeister  has 
searched,  in  vain,  for  a  heart,  in  the  large  Coro- 
nula  diadema.  The  vessels  of  the  arms  can  be 
distinctly  seen  through  the  transparent  integu- 
ments of  the  ciliated  processes ;  there  are,  in 
each  process,  two  vessels,  one  of  which  runs 
very  superficially  between  the  two  rows  of 
hairs.  ( Fig.  343.^ 

Cuvier  regarded  the  anterior  canal  of  the 
peduncle  in  Anatifa  as  the  nourishing  vessel  of 
that  organ. 

Respiration. — The  principal  organs  concern- 
ed in  respiration  are,  in  the  Lepads,  certain 
tapering  filamentary  processes  attached  to  the 
sides  of  the  anterior  part  of  the  body,  which 
are  regarded  as  the  branchiae  (d,  g,  fig.  340)  : 
in  most  of  the  Balanids,  they  assume  the  form 
of  two  leaf-like  membranes  with  fringed  mar- 
gins, and  are  attached  to  the  inner  surface  of 


690 


CIRRHOPODA. 


the  mantle.  Professor  Burmeister  describes 
the  gills  of  Coronula  diadema  as  broad  mem- 
branous expansions,  of  a  semicircular  form, 
attached  to  the  sides  of  the  visceral  mass  by  a 
narrow  pedicle.  They  are  composed  of  two 
tunics  arranged  in  deep  and  narrow  transverse 
plaits.  The  number  of  the  branchiae  in  the 
Lepads  varies  from  four  to  sixteen.  They  are 
composed  of  soft  cellular  tissue,  and  have  a 
smooth  surface. 

The  arms  ( h,  h,  Jig.  340),  which  constitute 
so  large  a  portion  of  the  general  mass  of  all  the 
Cirripeds,  and  which  form  their  most  distinc- 
tive feature,  must  be  regarded  as  subservient 
chiefly  to  the  function  of  respiration ;  although, 
by  producing  currents  in  the  water,  which 
bring  food  within  reach  of  the  jaws,  they  minis- 
ter also  to  the  digestive  function.  In  all  the 
known  species,  both  of  Lepads  and  Balanids, 
these  arms  are  twelve  in  number,  six  on  either 
side,  arranged  symmetrically.  Each  arm  is 
composed  of  a  short  fleshy  peduncle,  having 
three  articulations,  and  two  horny  articulated 
processes,  compressed  laterally,  of  equal  length, 
ciliated  on  their  internal  surfaces,  and  coiled 
up  in  a  spiral  of  one  turn.  On  their  internal 
surface  there  is  a  coating  of  a  black  pigment  in 
spots.  Each  joint  is  provided  with  a  double 
row  of  hairs  of  different  lengths.  (Fig.  343.) 

Fig.  343. 


A  part  of  one  of  the  arms  considerably  magnified. 

In  Anatifa,  the  first  pair  of  arms  is  thicker  and 
stronger  than  the  others ;  the  sixth  pair  is  the 
longest.  Dr.  Grant  says,  "  the  arms  are  not 
only  minutely  jointed  to  their  extreme  points, 
but,  also,  the  innumerable  fine  cilia  which  pro- 
ject inwards  from  their  surface  are  themselves 
minutely  jointed,  and  by  the  aid  of  the  micro- 
scope, we  can  perceive  that  these  jointed  cilia 
are  also  ciliated  on  their  margins." 

When  the  animal  is  at  rest,  with  the  valves 
of  the  shell  closed,  the  arms  are  coiled  up,  and 
lie  close  to  one  another;  but,  at  other  times, 
circumstances  being  favourable  to  the  perform- 
ance of  the  function  of  respiration,  they  are  ex- 
tended simultaneously  so  as  to  project  from  the 
shell, — radiate  and  plumose  in  their  arrange- 
ment. Many  species  extend  and  contract  their 
arms  with  considerable  rapidity,  as  often  as 
forty  or  sixty  times  in  a  minute;  the  smaller 
species  more  frequently  than  the  larger. 

Considering  how  extensive  the  surface  is 
which  is  exposed  in  the  arms  between  the  two 
rows  of  cilia,  and  that  a  vessel  seems  to  run 
immediately  beneath  the  delicate  covering  of 
these  organs  in  that  situation,  it  appears  proba- 
ble that  the  arms  are  very  efficient  agents  in  the 
function  of  respiration. 

Secretion. —  We  have  failed  to  ascertain  satis- 


factorily the  structure  of  the  secreting  apparatus 
by  which  the  shells  of  the  Cirripeds  are  formed. 
In  the  Lepads,  the  organs  must  be  imbedded 
in  the  ligamentous  membrane  by  which  the 
valves  are  united  :  and  in  the  Balanids,  they  are 
arranged  in  six  rows  along  the  outer  surface  of 
the  mantle,  and  around  the  base;  but,  as  in 
acephalous  mollusca,  they  are  too  small  to  ad- 
mit of  their  structure  being  particularly  exa- 
mined. The  external  surface  of  the  mantle  in 
the  Balanids  has  also  the  power  of  secreting 
calcareous  matter,  with  which  to  increase  the 
thickness  of  the  shell. 

Reproduction. — It  is  not  yet  accurately  de- 
termined what  are  the  organs  of  reproduction 
in  these  animals.  That  which  was  regarded  by 
Cuvier  as  the  ovary  in  the  Lepads,  is  supposed 
by  Professor  Wagner  and  M.  St.  Ange  to  be 
the  testicle;  while  Professor  Burmeister  has 
satisfied  himself  that  it  is  the  liver.  The  ex- 
tent, structure,  and  relations  of  the  ovary  are 
still  doubtful.  It  is  certain,  however,  that  all 
the  known  Cirripeds  are  hermaphrodite. 

The  testicle,  according  to  Professor  Wagner 
and  M.  St.  Ange,  is  a  large  granular  organ 
(y>  fi&-  344),  expanded  over  the  sides  of  the 

Fig.  344. 


visceral  mass,  and  around  the  digestive  canal, 
from  the  stomach  to  the  anus,  passing  even  into 
the  bases  of  the  arms,  immediately  beneath  the 
muscular  tunics  which  cover  the  body  on  both 
sides.  It  is  composed  of  numerous  minute 
lobules,  about  gigth  of  an  inch  in  diameter  in 
the  common  Lepads,  soft,  white,  grouped  toge- 
ther by  branched  ducts  ( q,  q,  Jig.  344),  which, 
after  uniting  into  three  or  four  principal  trunks,* 
meet  in  a  large  central  receptacle  (r),  some- 
what analogous  in  relative  function  to  the  vas 
deferens  of  vertebrate  animals.  The  seminal 
fluid  passes  from  this  central  receptacle  by  a 
short  and  straight  duct  into  a  large  canal  (t,  t), 
which  may  be  compared  to  the  seminal  vesicle. 
It  pursues  a  tortuous  course  towards  the  base 
of  the  tubular  process,  where  (&)  it  is  joined  by 
its  fellow  of  the  other  side,  and  enters  the  canal 

*  This  description  does  not  accord  with  the  result 
of  Professor  Burmeister's  researches.  Instead  of 
a  regular  series  of  branched  vessels,  he  says  that 
he  met  with  nothing  but  an  irregularly  arranged 
mesh  of  thready  fibres  lying  between  what  he  be- 
lieved to  be  the  liver  (described  above  as  the  testi- 
cle) and  the  intestinal  canal. 


CIRRHOPODA. 


691 


of  the  process  which  forms  a  kind  of  caudal 
prolongation  of  the  abdomen  (/',  f).  This 
canal  runs  to  the  distal  extremity,  and  opens 
by  a  minute  orifice  fringed  with  very  fine  hairs. 
In  Otion  Cuvieri  the  two  canals  are  continued 
distinct  to  the  very  point  of  the  process,  where 
there  are  two  openings.*  The  walls  of  the 
organ,  which  we  have  compared  to  the  seminal 
vesicle,  have  a  glandular  structure,  which 
Cuvier  imagined  to  be  the  testicle.  The  re- 
searches of  Professor  Burmeister  have  led  him 
to  the  same  conclusion.  He  says  it  can  be  no- 
thing but  the  testicle.f  Cuvier,  as  well  as 
Lamarck,  regarded  what  we  have  called  the 
testicle  as  the  ovary,  and  believed  that  the  ova 
were  impregnated,  in  the  course  of  their  passage 
along  the  oviducts,  by  the  seminal  fluid  flowing 
from  the  testicle  investing  these  canals.  The 
granular  lobules  of  the  true  testicle,  which  were 
supposed  to  be  immature  ova,  are  found  always 
in  the  same  state,  and  what  are  more  distinctly 
ova  are  found  within  the  peduncle.J 

The  lengthened  tubular  process  (Y,  t',fg. 
344),  through  which  the  excretory  duct  of  the 
testicle  passes,  is  articulated;  the  margin  of 
each  joint  is  fringed  with  minute  hairs.  In 
Otion  and  Coronula,  Burmeister  found  large 
canals  closed  at  both  extremities,  within  the 
process,  in  addition  to  the  ducts  from  the  testi- 
cle. This  organ  is  generally  found  after  death 
bent  upwards  on  the  abdominal  surface  ;  but, 
during  life,  it  is  in  continual  motion.  Its  use 
is,  probably,  to  carry  the  seminal  fluid  back- 
wards beyond  the  current  caused  by  the  move- 
ments of  the  arms,  in  the  event  of  there  being 
mutual  impregnation  between  separate  indivi- 
duals ;  or  towards  the  mouths  of  certain  ducts 
which  communicate  with  the  ovary  within  the 
peduncle,  in  case  of  self-impregnation  taking 
place.  In  this  view  it  must  be  regarded  as 
the  penis  :  and  it  is  so  called  by  the  most 
recent  authors  on  the  subject — Wagner  and 
Burmeister.  Mr.  Thompson  calls  it  an  ovipo- 
sitor ;  and  conjectures  that,  after  their  expul- 
sion from  the  ovary,  (understanding  by  this 
what  we  regard  as  the  testicle,)  the  eggs  are 
conveyed  by  it  into  the  cellular  texture  of  the 
pedicle.  How  they  pass  from  this  depository 
into  the  general  cavity,  where  they  afterwards 
form  two  or  three  foliated  groups,  he  confesses 
himself  unable  to  explain. 

The  peduncle  of  the  Lepads  was  formerly 
regarded  merely  as  an  organ  of  support,  and 
even  Cuvier  discovered  within  it  nothing  but 
what  appeared  to  him  to  be  a  homogeneous 
pulp,  surrounded  by  muscular  tissue.  But,  at 
certain  seasons  of  the  year,  at  least,  there  are, 
very  distinctly  developed,  throughout  the  greater 
part  of  the  soft  matter  which  constitutes  the 
bulk  of  the  organ  contained  within  the  dense 
cartilaginous  and  muscular  tunics,  certain  oval 
granules,  regular,  and  uniform  in  shape,  and 
gradually  increasing  in  size.  Poli  and  Lamarck 

*  Bunneister,  Beitrage,  p.  46. 

t  Op.  cit.  p.  44. 

$  Professor  Wagner  is  satisfied  that  nothing  but 
the  discovery  of  spermatic  animalcules  can  assure 
us  against  error  in  our  attempts  to  determine  what 
is  the  testicle. 


were  of  opinion  that  these  were  truly  eggs,  but 
held  that  they  were  originally  formed  in  the 
granular  organ  surrounding  the  intestine,  (now 
regarded  as  the  testicle,)  and  merely  deposited 
here  temporarily.  But  the  recent  researches  of 
Professor  Wagner  and  M.  St.  Ange  have  ren- 
dered it  probable  that  it  is  the  ovary  which  is 
contained  within  the  peduncle.  The  organ  in 
question  seems  to  occupy  the  whole  of  the  pe- 
duncle within  the  layers  of  muscular  tissue. 
It  is  separated  from  the  visceral  cavity  by  a 
fine  membrane  which  lines  that  cavity,  and  is  a 
reflexion  of  the  mantle.  A  transverse  section 
of  the  ovary  shews  the  eggs  most  fully  deve- 
loped towards  the  outer  margin,  and  scarcely 
formed  in  the  centre.  There  are  also  seen  in 
the  same  section  two  canals  which  run  longitu- 
dinally through  the  organ,  one  near  that  side 
of  the  margin  which  corresponds  to  the  anterior 
aspect  of  the  body  of  the  animal,  the  other  in  a 
similar  situation  on  the  dorsal  aspect.  Of  these 
canals,  the  anterior  is  the  larger ;  and  it  alone 
was  described  by  Cuvier,  who  regarded  it  as 
connected  with  the  circulating  system.  The 
other  was  first  described  by  M.  St.  Ange,  who 
satisfied  himself  that  it  is  a  true  oviduct.  In 
Anatifa,  he  traced  it  pursuing  a  straight  course 
through  the  ovary,  and  leaving  it  as  a  perfect 
canal  just  at  the  posterior  and  inferior  angle  of 
the  organ,  thence  passing  on  the  outer  surface 
of  the  lining  of  the  visceral  cavity,  in  the  groove 
of  the  dorsal  valve,  and  terminating  in  an  orifice 
opening  into  the  visceral  cavity  not  far  from  the 
brachial  slit.*  We  have  found  a  structure 
exactly  resembling  the  above  in  Otion,  where, 
however,  instead  of  opening  into  the  general 
cavity  of  the  visceral  sac,  the  duct  is  bifurcated 
just  between  the  two  auriform  appendages,  into 
each  of  which  one  of  the  branches  of  the  duct 
enters  and  opens.  M.  St.  Ange  found  eggs 
in  progress  through  this  duct;  and  they  are 
frequently  .found,  arranged  in  groups  or  packets, 
two  or  three  in  number,  within  the  cavity  of 
the  mantle.  We  have  not  yet  seen  them  in  the 
duct ;  but  the  whole  structure  of  the  parts  in 
question  seems  to  indicate  their  adaptation  to 
the  function  assigned  to  them  by  M.  St.  Ange. 
This  being  the  case  with  regard  to  Anatifa,  it 
appears  to  be  very  probable  that  the  use  of  the 
singular  auriform  appendages  in  Otion  is  to 
afford  a  convenient  lodging  for  the  eggs  before 
the  young  are  hatched.  Their  deep  sinuosities 
and  folds  seem  to  adapt  them  admirably  to 
this  purpose.  Packets  of  eggs,  however,  are 
found  within  the  cavity  of  the  mantle  in  this 
species  as  in  others.  According  to  Burmeister, 
these  packets  are  unattached,  excepting  in  the 
earliest  stage  of  development ;  but  Wagner  has 
generally  found  them  fixed  to  a  process  of  the 
mantle,  situated  near  the  adductor  muscle  of 

*  Professor  Wagner  says,  "  at  the  base  of  the 
dorsal  valve  there  exists  a  slit  in  the  mantle  which 
leads  into  the  canal  that  runs  through  the  peduncle. 
I  presume  that  this  canal  serves  as  an  oviduct,  and 
that  the  slit  is  analogous  to  the  opening  of  the 
branchial  canal  in  the  bivalves/'  (in  Archiv  fiir 
Anat.  Physiol.  &c.  von  D.  J.  Miiller,  1834,  No.  5, 
quoted  in  Ann.  des  Sc.  Nat.  iv.  n.  s.)  We  are  not 
aware  what  species  was  anatomized  by  Professor 
Wagner. 


692 


CIRRHOPODA. 


the  shell ;  which  process  is,  at  times,  so  much 
elongated  as  to  admit  of  the  eggs  hanging  out 
in  groups  from  the  brachial  aperture,  beyond 
the  extremities  of  the  arms.  Burmeister  has 
observed  that,  after  the  escape  of  the  embryo, 
the  shells  remain  connected  with  the  parent, 
forming  a  loose  net- work.  This  author  seems 
to  regard  these  groups  of  eggs  within  the  man- 
tle, and  the  tissue  in  which  they  are  imbedded, 
as  constituting  the  true  ovary.  In  each  of  the 
individuals  of  Anatifa  striata  which  came  under 
his  observation,  he  computed  that  there  were 
about  4000  eggs  in  the  ovary.  Mr.  Thompson 
calls  these  groups  of  ova  conceptacles ;  and 
says  that  "  each  has  a  separate  attachment  at 
the  sides  of  the  animal  to  the  septum,  which 
divides  the  cavity  occupied  by  the  animal  from 
that  of  the  pedicle."*  The  retention  of  their 
ova,  grouped  in  separate  packets  on  the  surface 
of  their  bodies,  after  their  expulsion  from  the 
ovary,  constitutes  another  point  of  resemblance 
between  the  Cirripeds  and  Crustaceous  animals. 

With  regard  to  the  anterior  canal  within  the 
ovary,  little  has  yet  been  determined.  We 
have  particularly  examined  it  in  Otion,  and 
find  that,  like  its  fellow  of  the  dorsal  aspect,  it 
leaves  the  ovary  at  its  inferior  edge,  whence  it 
opens  into  a  small  cavity  situated  between  the 
intervalvular  ligament  and  the  lining  membrane 
of  the  visceral  cavity.  We  have  not  succeeded 
in  discovering  any  orifice  in  the  walls  of  this 
cavity,  although,  from  the  results  of  some  of 
our  experiments  we  think  it  probable  that  there 
exists  a  small  one  just  above  the  brachial  slit. 
If  so,  is  it  not  likely  that  this  is  the  passage  in- 
tended for  conveying  the  fecundating  liquor 
from  the  orifice  of  the  tubular  process  connected 
with  the  male  organs  to  the  ovary  ?  When  the 
body  is  exserted  through  the  brachial  slit,  the 
point  of  the  process  can  easily  be  brought  into 
contact  with  the  outer  surface  of  the  cavity 
above  described. 

The  development  of  the  egg  and  the  young 
of  the  Cirripeds  has  recently  become  an  object 
of  interesting  inquiry  in  consequence  of  the 
novel  results  announced  by  Mr.  J.  V.  Thomp- 
son in  his  "  Zoological  Researches,"  (1830, 
4th  Memoir.)  This  gentleman  has  published 
an  account  of  observations  made  on  what  he 
believed  to  be  the  young  of  Balanids,  from 
which  he  concludes  that,  on  their  first  exclusion 
from  the  egg,  they  closely  resemble  some  of 
the  branchiopodous  Crustacea, — that  they  pos- 
sess the  power  of  free  locomotion  through  the 
water  by  means  of  setiferous  arms  projecting 
from  within  a  bivalve  shell, — and  that  they 
have  very  obvious  pedunculated  eyes.  Minute 
animals,  bearing  these  characters,  and  having 
some  resemblance  to  species  of  the  genus 
Cypris,  were  placed  by  Mr.  Thompson  in  a 
glassful  of  sea-water.  Soon  after,  on  looking 
for  them,  he  could  not  find  them  in  the  water, 
but  he  found  in  their  room  several  very  young 
balanids,  which,  from  the  appearance  they  pre- 
sented, he  concluded  to  be  really  the  same 
animals  that  he  had  originally  placed  in  the 
water,  changed  by  metamorphosis.  Mr.  Thomp- 

*  Phil.  Trans.  1835,  356. 


son  has  not  seen  the  change  actually  going  on, 
but  he  has  satisfied  himself  that  what  he  re- 
gards as  the  free-moving  embryo  fixes  itself  by 
a  spot  on  its  dorsal  aspect  between  the  two 
shells,  which  spot  can  be  seen  during  its  free 
state.  When  fixed,  the  base  of  adherence  ap- 
pears to  be  broad  like  that  of  an  Actinia :  from 
this  it  rises  in  a  conical  form,  truncated.  The 
flat  sides  of  this  cone  are  coated  with  six  shelly 
plates,  so  arranged  as  to  leave  a  large  space  in 
the  middle  uncovered.  This  space  is  closed 
by  the  old  shells  of  the  embryo  state,  which 
are  made  to  move  up  and  down  as  the  opercule 
does  in  the  adult  animal,  admitting  of  the 
egress  and  ingress  of  the  arms  at  the  animal's 
pleasure.  Through  this  shell  two  large  black 
spots  like  eyes  can  be  distinguished.  Mr. 
Thompson  found  in  the  young  of  the  Balanids, 
six  pairs  of  arms,  cleft ;  each  arm  with  two  ar- 
ticulations. The  first  casting  of  the  shell,  after 
the  animal  has  fixed  itself,  is  followed  by  an 
increase  in  the  number  of  articulations  in  each 
arm ;  and  this  number  is  further  added  to  at 
every  succeeding  shell-casting.  Even  the  old 
full-grown  animals,  according  to  Mr.  Thomp- 
son, cast  their  shells. 

Very  recently  Mr.  Thompson  has  made  a 
still  more  satisfactory  series  of  observations  on 
the  development  of  some  of  the  Lepads,  of  the 
genera  Cineras,  Otion,  and  Lepas.  These  he 
obtained  from  the  bottoms  of  vessels  in  the 
harbour  of  Cork.  They  hatched  eggs  in  large 
numbers,  and  afforded  him  the  means  of  ascer- 
taining, entirely  to  his  own  satisfaction,  that,  at 
its  first  exclusion  from  the  egg,  the  Lepad,  like 
the  Balanid,  is  a  natatory  crab.  He  found  a 
considerable  difference  between  the  larv<£  of 
the  two  classes.  The  newly-discovered  one  of 
the  Lepads  he  describes  as  "  a  tailed  monocu- 
lus,  with  three  pairs  of  members,  the  most  an- 
terior of  which  are  simple,  the  others  bifid, 
having  its  back  covered  by  an  ample  shield, 
terminating  anteriorly  in  two  extended  horns, 
and  posteriorly  in  a  simple  elongated  spinous 
process." 

The  general  appearance  of  this  larva  is  not 
unlike  that  of  the  Argulus  armiger  of  La- 
treille.* 

Very  recently  Messrs.  Audouin,f  Wagner,} 
and  Burmeister,§  have  corroborated  the  state- 
ments and  supported  the  views  of  Mr.  Thomp- 
son. Professor  Burmeister  has  detailed  the 
results  of  his  observations  with  great  minute- 
ness. It  appears  that  they  were  made  chiefly 
on  individuals  of  Anatifa  striata,  procured  in 
the  North  Atlantic  Ocean,  and  preserved  in 
spirits ;  partly  also  on  Lepas  anserifera.  (Linn.) 
The  results  of  these  observations  have  led  Pro- 
fessor B.  to  divide  the  development  of  the  Cir- 
ripeds into  five  stages  or  periods.  The^rs^  of 
these  is  the  state  of  egg ;  the  second  is  that  of 

*  Phil.  Trans.  1835,  pt.  ii.  355.  "  Discovery  of 
the  Metamorphosis  in  the  second  type  of  the  Cirri- 
peds," &c. 

f  Ann.  des  Sc.  Nat.  n.  s.  iii.  31. 

j  Miiller's  Archiv,  No.  5,  1834,  and  Beitrage  zur 
verglcich.  pliys.  des  Blutes.  Leipzig,  1833. 

§  Beitrage  zur  Naturgesch.  der  Rankenfusser. 
Berlin,  1834. 


CIRRIIOPODA. 


693 


free  locomotion ;  the  third  is  that  in  which  the 
young  becomes  encased  in  a  shell,  and  fixes 
itself;  in  l\\e  fourth  stage,  the  young  gradually 
assumes  the  characters  of  the  adult;  ihe  fifth 
stage  is  that  of  perfect  development. 

First  stage. — The  egg.  Its  outer  covering 
is  a  very  delicate  membrane.  The  yolk  is  yel- 
lowish-red, clouded,  and  marked  with  two 
rows  of  small  spots,  globule-like,  distinct  at 
one  end,  running  together  at  the  other.  The 
eggs  in  the  central  parts  of  the  ovary  are  consi- 
derably further  advanced  than  those  in  the  cir- 
cumference. Through  the  transparent  covering 
of  the  egg  the  general  form  of  the  embryo  can 
be  seen. 

Second  stage. — In  this  stage  the  young  Cir- 
riped  resembles  the  fry  of  Cyclops  or  Daphnia 
in  its  external  characters.  It  is  provided  with 
two  long  antennae  and  three  pairs  of  feet  (arms?) 
placed  along  its  ventral  surface.*  Each  foot 
of  the  first  pair  is  single,  and  is  furnished  with 
bristles  at  its  free  extremity.  Each  of  the  other 
pairs  is  divided  into  two  members,  also  tipped 
with  bristles.  The  posterior  part  of  the  body 
is  tapering,  compressed,  and  slightly  bifurcated 
at  its  extremity,  where  it  is  beset  with  bristles. 
No  eyes  could  be  seen  in  this  stage,  but  Pro- 
fessor Burmeister  nevertheless  conjectures  that 
they  really  do  exist.  The  appearance  of  two 
rows  of  small  globules  on  the  surface  of  the 
body  continues  to  present  itself,  but  here  they 
are  more  numerous,  although  not  larger.  The 
middle  part  of  the  body  is  clear  and  transparent. 

Third  stage. — Materials  for  the  description 
of  this  stage  were  obtained  by  Burmeister 
from  the  examination  of  only  one  individual, 
which  was  found  attached  to  the  frond  of  a 
fucus  hard  by  the  bases  of  some  adult  indivi- 
duals. The  shell,  in  this  the  first  stage  of  its 
growth,  is  of  leathery  consistence,  and  formed 
of  one  piece,  placed  dorsally.  A  fleshy  protu- 
berance serves  as  the  peduncle.  The  organs  by 
which  the  young  animal  fixes  itself  are  evi- 
dently the  long  antennae  situated  near  the 
mouth.  Behind  these  are  placed  the  very  large 
eyes.  Burmeister  satisfied  himself  of  the  ex- 
istence of  a  single  transparent  cornea,  and  saw 
behind  it  a  round  black  spot,  but  no  lens.  The 
two  eyes  are  very  closely  approximated  by  their 
bases.  Both  the  eyes  and  the  brownish  con- 
tents of  the  alimentary  canal  can  be  distin- 
guished through  the  translucent  shell.  In  the 
structure  of  the  posterior  part  of  the  body  there 
is  no  great  change  from  the  former  stage.  Each 
arm  of  the  first  pair  is  single,  and  consists  of 
three  articulations,  of  which  the  basilar  is  the 
greatest :  the  smallest  and  terminal  one  bears 
four  long  stiff  bristles.  The  arms  of  the  follow- 
ing pair  are  not  single,  but  each  is  divided  into 
two  small  articulated  processes.  The  little 
globules  of  the  two  former  stages  are  not  dis- 
cernible in  this. 

*  The  circumstance  of  there  being  a  smaller 
number  of  arms  in  the  young  than  in  the  adult,  re- 
minds us  of  the  same  being  the  case  in  several  of 
the  Branchiopodous  Crustacea;  and  the  want  of 
the  shell  in  young  Cirripeds  seems  to  point  out  a 
closer  analogy  between  them  and  Crustacea,  than 
between  them  and  Mollusca,  the  young  of  which 
are  covered  with  shell  in  the  egg. 


Fourth  stage.— This  stage  was  observed 
by  Professor  Burmeister  in  the  Lepas  ttnati- 
J'era  from  the  coasts  of  Chili.  All  the  indi- 
viduals examined  were  about  three-fourths 
of  a  line  in  length.  Soon  after  the  animal 
fixes  itself  the  old  integuments  are  thrown 
off.  The  eyes  and  the  antennae  are  entirely 
cast  off  along  with  these.  After  this  process 
had  been  completed,  the  space  within  the  man- 
tle was  found  to  be  filled  with  a  granular  pulta- 
ceous  mass,  at  first  occupying  the  greater  part 
of  the  cavity  of  the  shell,  and  covering  all  the 
young  animal.  This  appeared  to  M.  Burmeis- 
ter to  be  the  same  that  is  found  in  the  pedicle 
of  the  older  animals,  and  to  resemble  closely 
the  matter  contained  within  the  cavities  of  the 
shells  of  Coronulae  and  other  Balanids.  It  is 
by  a  sack-formed  process  of  the  mantle  filled 
with  this  yellowish  matter  that  the  peduncle  is 
first  formed.  At  the  time  of  the  animal's  fixing 
itself  the  shell  has  no  calcareous  points,  but  in 
the  course  of  this  stage  it  becomes  firm  and 
gradually  more  and  more  solid.  There  are 
now  six  pairs  of  feet,  each  of  three  articulations, 
and  terminated  by  bristles.  A  small  tail  of 
two  articulations  also  appears,  the  rudiments  of 
which,  however,  can  be  detected  in  the  former 
stage.  In  the  fifth  stage  the  process  of  deve- 
lopment is  completed. 

It  must  be  admitted  that  the  evidence  in 
favour  of  Mr.  Thompson's  opinions  on  this 
subject  is  by  no  means  conclusive.  There  is 
still  wanting  a  series  of  minute  and  careful  ob- 
servations on  the  first  appearance  and  motions 
of  the  embryo  immediately  after  its  exclusion 
from  the  egg ;  and  nothing  but  the  results  of 
such  a  series  can  settle  the  question  as  to  whe- 
ther there  be  a  real  metamorphosis  or  not. 

Mr.  Gray's  observations  have  led  him  to 
conclude  that  no  great  changes  of  structure, 
such  as  Mr.  Thompson's  views  presuppose, 
actually  take  place  ;  although,  in  examining  the 
mature  egg  of  Balanus  Cranchii,  he  found  the 
appearance  of  the  embryo  nearly  the  same  as  is 
described  by  Burmeister  as  being  that  of  the 
Lepads  in  the  second  stage  of  development. 
The  egg  of  this  Balanid  Mr.  Gray  ascertained 
to  be  one-fiftieth  of  an  inch  in  length.  He  de- 
scribes the  inclosed  animal  as  being  of  an  ovate 
form,  tapering  at  one  extremity,  truncated  and 
ciliated  at  the  other ;  bearing  a  general  resem- 
blance to  the  adult  animal,  but  furnished  with 
only  three  pairs  of  ciliated  arms ;  the  base  of 
each  arm  being  two-jointed.  He  found  only 
one  lengthened  process  attached  to  the  lower 
pair  of  arms;  but,  connected  with  the  two 
upper  pairs,  two  fusiform,  thick,  articulated 
and  ciliated  processes,  similar  to  those  of  the 
anterior  part  of  the  perfect  animal,  but  less 
elongated.  He  saw  no  shelly  covering.* 

We  have  not  yet  had  proper  opportunities  of 
devoting  attention  to  this  interesting  subject  so 
far  as  observations  on  the  living  animals  are 
concerned ;  but  we  have  no  doubt  of  its  veiy 
soon  meeting  with  a  clear  and  satisfactory  elu- 
cidation ;  meanwhile  we  may  remark  that  the 
structure  of  the  embryo  within  the  mature  egg 


115. 


Proceedings  of  Zool.   Soc.  Lond,  1833,  pt. 


694 


CIRRONOSIS— CONCHIFERA. 


(about  which  there  can  be  no  doubt)  is  such  as 
strongly  to  indicate  its  adaptation  to  free  loco- 
motion ;  and  that,  after  a  review  of  all  the  ob- 
servations that  have  been  published  on  the 
subject,  we  are  inclined  to  conclude  in  favour 
of  Mr.  Thompson's  opinion  that,  in  the  early 
stages  of  its  development,  the  young  Cirriped 
really  enjoys  locomotive  powers,  and  then  un- 
dergoes such  changes  of  structure  as  are  re- 
quired to  fit  it  for  its  altered  circumstances  in 
adult  age. 

BIBLIOGRAPHY.—  Leeuwenhoek,  Opera,  iii.  472. 
Lister,  Exercit.  anat.  1696,  p.  96.  Cuvier,  Mem. 
pour  servir  a  Thistoire  des  Mollusques,  1817.  La- 
marck, Anim.  sans  vertebres,  v.  377.  J.  V.  Thomp- 
son, Zoological  researches,  1830  ;  Fourth  Memoir  ; 
and  Phil.  Trans.  1835,  355.  Wagner,  in  Archiv 
fur  anat.  physiol.  &c.  von  D.  J.  Muller,  1834, 
No.  v.  Burmeister,  Beitrage  zur  Naturgeschichte 
der  Raukenftiesser,  Berlin,  1834.  Martin  St.  Ange, 
Memoire  sur  1'organization  des  Cirripedes  et  leurs 
rapports  naturels  avec  les  animaux  articules,  Paris, 

(John  Coldstream.) 


(K»#os,  fulvus  ; 
ubli 


CIRRONOSIS. 

morbus.J  In  a  memoir  published  by  M.  Lob- 
stein  in  the  first  volume  of  the  Repertoire 
d'  Anatomic  and  de  Physiologic*  for  the  year 
1826,  this  term  was  applied  to  what  that  author 
considers  to  be  a  disease  affecting  the  fetus  at 
an  early  period  of  intra-uterine  life.  The 
essential  characteristic  of  the  malady  consists 
in  the  serous  or  transparent  membranes  being 
dyed  of  a  beautiful  deep  golden  yellow 
colour.  "  The  disease  is,"  says  M.  Lobstein, 
"  an  internal  jaundice  of  the  peritoneum,  of 
the  pleura,  of  the  pericardium,  of  the  arachnoid, 
differing  from  the  ordinary  jaundice,  in  that 
it  does  not  affect  the  parenchymatous  cellular 
tissue  of  organs,  nor  the  subcutaneous  tissue, 
nor  the  skin,  the  usual  seats  of  that  disease." 

Lobstein  published  the  first  account  of  the 
occurrence  of  these  appearances  in  two  five- 
month  foetuses,  in  his  Rapports  sur  les  travaux 
executes  a  TAmphitheatre  d'Anatomie  de 
Strasbourg.!  Since  that  time  additional  cases 
were  presented  to  his  attention,  from  which  he 
ascertained  that  the  yellow  staining  was  not 
confined  to  the  serous  membranes  only,  but 
also  was  found  in  the  nervous  tissues,  espe- 
cially those  of  the  spinal  marrow  and  encepha- 
lon.  By  the  aid  of  the  microscope  he  perceived 
that  the  substance  of  the  marrow  seemed  to 
be  composed,  as  it  were,  of  small  grains  of  a 
lemon  yellow  colour,  mixed  with  a  white  and 
pulpy  substance,  as  if  a  very  fine  gold-coloured 
powder  had  been  intimately  mixed  with  a  soft 
and  semi-transparent  jelly.  In  these  cases  the 
thoracic  portion  of  the  sympathetic  also  exhi- 
bited a  similar  colour,  and  the  ganglia  were 
somewhat  swollen,  and  it  was  ascertained  by 
the  microscope  that  the  stain  was  equally 
inherent  in  the  nervous  substance  of  the  ganglia 
as  in  that  of  the  spinal  marrow. 

It  is  impossible  to  remove  the  yellow  stain 

*  Rep.  d'Anat.  et  de  Phys.,  t.  i.  p.  141. 
t  Page  26,  ed.  in  4to. 


from  the  structures  in  this  condition  either  by 
ablution  or  immersion  for  any  length  of  time 
in  alcohol  or  water.  The  intensity  of  the 
colour  was  not  diminished  in  preparations 
which  had  been  preserved  in  spirits  for  seven- 
teen years,  neither  was  it  affected  by  the  action 
of  light. 

The  difficulty  of  accounting  for  the  pheno- 
mena which  constitute  this  disease  of  the 
embryo  is  much  increased  by  the  fact  that 
cirronosis  has  hitherto  been  observed  only  in 
three  or  five  month  foetuses.  As  at  this  period 
the  biliary  secretion  has  not  begun  to  be  formed 
in  the  usual  way,  we  cannot  attribute  the 
occurrence  of  this  disease  to  any  of  the  causes 
which  give  rise  to  ordinary  jaundice,  so  com- 
monly met  with  in  the  foetus  at  and  shortly 
after  birth.  There  seems,  however,  to  be  no 
reason  to  doubt  that  the  elementary  constituents 
of  the  biliary  secretion  may  already  exist  in 
the  blood  at  an  early  period  of  intra-uterine 
life,  and  that  from  them  the  stain  may  have 
been  communicated  to  the  serous  membranes 
and  nervous  tissues.  But  we  cannot  but 
express  our  concurrence  in  the  opinion  of 
Andral,  that  cirronosis  differs  only  in  situa- 
tion from  the  ordinary  icterus  infantum  or 
neonatorum;  there  being  this  remarkable  dis- 
tinction also,  that  the  tissues  which  are  the  seat 
of  the  colour  in  cirronosis  are  rarely  affected 
in  jaundice. 

Although  the  observations  of  Lobstein  were 
first  published  ten  years  ago,  I  do  not  find 
that  they  have  been  confirmed  by  any  subse- 
quent observer.  The  preceding  account,  there- 
fore, of  this  disease  rests  entirely  upon  his 
authority,  and  is  drawn  up  chiefly  from  his 
paper  in  the  Repertoire  already  referred  to. 
(R.  B.  Todd.) 

COLLOID.    See  SCIRRHUS. 

CONCHIFERA.  Fr.  Conchiftres.  When 
we  take  a  general  view  of  the  organization  of 
the  extensive  series  of  Mollusca,  two  prin- 
cipal classes  are  readily  distinguished,  one  of 
which  has  been  raised  to  the  rank  of  the  pri- 
mordial division  of  the  animal  kingdom  by 
Lamarck  ;  this  class,  comprising  the  whole  of 
the  Acephala  of  Cuvier,  as  well  as  the  Bra- 
chiopoda,  has  received  the  name  of  CONCHI- 
FERA. 

The  mollusks  included  in  the  class  of 
Conchifera  present  peculiar  characters  which 
prevent  their  being  confounded  in  any  point 
of  the  series  with  the  other  classes  of  the  same 
sub-kingdom.  They  are  all  contained  within 
a  bivalve  shell,  generally  articulated  after 
the  manner  of  a  hinge;  to  this  shell  the 
animal  is  attached  by  one  or  several  muscles, 
and  the  shell  itself  is  secreted  by  a  fleshy 
envelope,  generally  thin,  but  having  the  edge 
thickened,  to  which  naturalists  agree  in  giv- 
ing the  name  of  mantle.  The  animal,  of  a 
structure  more  simple  than  other  mollusks,  has 
no  head;  the  mouth  is  pierced  at  the  anterior 
extremity  and  is  the  entrance  to  organs  of  di- 
gestion, consisting  of  a  stomach,  an  intestine 
of  different  lengths,  an  anus,  and  an  organ 


CONCIIIFERA. 


695 


for  secreting  bile.  Circulation  is  performed 
by  means  of  a  heart  generally  symmetrical, 
the  ventricle  of  which  surrounds  the  rectum. 
Respiration  is  effected  by  means  of  four  bran- 
chial leaflets,  equal  in  size  and  symmetrical, 
arranged  on  either  side  of  the  body.  Gene- 
ration is  simple ;  the  Conchifera  are  endowed 
with  hermaphrodism  adequate  to  the  continu- 
ation of  the  species  ;  every  individual  has  an 
ovary  included  among  the  general  mass  of  the 
viscera.  The  nervous  system  does  not  form  a 
complete  ring  around  the  esophagus ;  ganglia 
are  found  towards  the  anterior  and  posterior 
parts  of  the  animal,  and  lateral  and  very  long 
filaments  form  a  ring  within  which  the  visceral 
mass  is  included. 

Before  entering  upon  the  more  particular 
description  of  the  organs  which  have  just  been 
mentioned,  it  is  essential  as  a  preliminary  to 
institute  some  order  among  the  members  of 
the  class  Conchifera,  to  throw  them  into  a  few 
grand  divisions  by  which  the  labour  of  de- 
scription, in  many  particulars,  will  be  very 
much  abridged. 

Lamarck  divided  the  Conchifera  into  two 
grand  orders,  Dimyaria  and  Monomyaria. 
We  are  of  opinion  that  this  division  may  be 


First  sub-class. 

BRACHIOPODA, 
Or  POLYMYARIA 


Second  sub-class. 

DIMYARIA 


preserved  with  some  slight  modifications ;  and, 
farther,  that  it  is  necessary  to  establish  a  third 
order  equal  in  importance  to  the  two  others, 
and  including  the  Brachiopoda.  The  ana- 
tomical inquiries  of  Cuvier,  and  those,  still 
more  recent  in  their  date,  of  Mr.  Owen  into 
the  structure  of  the  Brachiopoda  will  not  allow 
us  any  longer  to  regard  these  animals  as  per- 
taining to  the  family  of  monomyary  Conchi- 
fers.  These  inquiries  also  prove  that  Cuvier, 
in  forming  the  Brachiopoda  into  a  particular 
class  of  Mollusca,  disjoined  them  in  too  great 
a  degree  from  their  congeners.  It  is  from  re- 
garding both  of  these  views  as  carried  too  far, 
that  we  have  been  led  to  propose  a  new  divi- 
sion which  to  us  appears  to  be  called  for,  and 
to  be  preferable  to  either  of  the  others ;  this  is 
to  restore  the  Brachiopoda  to  the  type  of  pro- 
per Conchifera,  and  to  establish  a  third  order 
of  this  family  for  their  especial  reception,  to 
which  the  title  of  Polymyaria  might  be  given. 
Instead  of  placing  this  order  at  the  end  of  the 
Conchifera,  however,  it  appears  better  to  set  it 
at  the  head,  especially  if  the  analytic  method 
of  Lamarck  be  adopted  as  the  basis  of  the 
classification.  The  Conchifera  we  should,  then, 
propose  to  arrange  in  the  following  order : 


fist  sub-order :  valves  articulated. 
C  2nd  sub-order :  valves  free. 


Order    1st.        The  C  1st  sub-order :  shell  regular. 

lobes  of  the  mantle  < 

more  or  less  united  C.  2nd  sub-order :  shell  irregular. 

Order  2nd.       The  C  1st  sub-order:  shell  regular, 
lobes  of  the  mantle  < 
.disjoined     .     .     .  C. 2nd  sub-order :  shell  irregular. 


Third  sub-class.    C  Border:  afoot. 
MONOMYARIA     1 2nd  order :  no  foot. 


The  organization  of  the  Brachiopoda  being 
more  simple  than  that  of  the  other  Conchifera, 
renders  it  proper  to  place  this  order  at  the  be- 
ginning of  the  class.  The  Dimyaria  having  an 
organization  somewhat  less  complex  than  the 
Monomyaria  constitute  an  intermediate  order, 
which  is  the  most  numerous  of  the  three ;  the 
Monomyaria  terminate  the  series. 

To  facilitate  the  comprehension  of  the  brief 
descriptions  which  we  shall  give  of  the  dif- 
ferent parts  of  the  Conchifera,  it  seems  neces- 
sary to  state  precisely  the  position  in  which 
the  animal  must  be  placed  in  order  to  be  suit- 
ably observed.  The  animal,  then,  is  supposed 
to  be  walking  before  the  observer,  included 
within  six  planes  to  which  its  different  parts 
are  referred.  The  head  or  the  oral  aperture 
indicates  the  anterior  extremity  of  the  creature. 
This  extremity  is  directed  forwards,  its  pos- 
terior extremity  backwards.  The  back  cor- 
responds to  the  superior  plane ;  the  belly  and 
foot  correspond  to  the  inferior  plane,  and  the 


flanks  of  the  animal  to  the  lateral  planes,  one 
of  which  is  to  the  right,  the  other  to  the  left. 
The  two  accompanying  figures  (fig.  345)  will 
suffice  to  give  an  idea  of  the  relations  of  one 
of  these  animals  to  the  different  planes  within 
which  it  is  supposed  to  be  included. 

The  organization  of  the  Conchifera  is  simple 
enough.     The  researches  of  anatomists  have 
shown  that  these  animals  are  provided 
digestion, 
circulation, 


with  organs  of 

and  (in  the  greater  number) 
locomotion;  with  a  skin 
or  envelope  common  to  the  whole  of  these 
organs  ;  and  a  nervous  system  bringing  the 
different  systems  into  mutual  relation  with  each 
other. 

Of  the  organs  of  digestion,  —  In  the  Con- 
chifera, as  among  other  animals,  these  organs 
begin  at  the  oral  aperture.  This  aperture 


CONCHIFERA. 
Fig.  345. 


(a,  fig.  346)  placed  at  Fig.  346. 

the  anterior  part  of  the 
animal  is  deeply  hid- 
den between  the  foot 
(b,  Jig.  346),  and  the 
anterior  retractor  mus- 
cle (c)  in  the  Dimyaria, 
and  under  a  kind  of 
cowl  formed  by  the 
mantle  in  the  Mono- 
myaria.  The  mouth  is 
in  the  form  of  a  trans- 
verse slit,  comprised 
between  two  lips,  ge- 
nerally thin  and  nar- 
row, as  in  almost  all 
the  Dimyaria,  or  lo- 
bated  and  digitated, 
as  in  some  of  the 
Monomyaria,  (a,  Jig. 
348).  The  lips  ex- 
tend on  either  side  in  the  form  of  two  flat- 
tened smaller  appendages,  more  or  less  elon- 
gated, occasionally  truncated,  streaked  or 
laminated  on  their  internal  surface,  and  to 
which  the  title  of  labial  palps  has  by  general 
consent  been  given,  (d,fj.g.  346,  c,Jig.  348.) 

The  mouth  in  the  Conchifera  never  presents 
any  part  that  is  hard.  In  the  greater  number 
of  these  animals  it  terminates  without  any 
intermediate  passage  in  a  stomach,  the  form 
of  which  is  subject  to  but  little  variety. 
When  there  is  an  oesophagus  (a,  Jig.  347),  it 
is  variable  both  in  point  of  length  and  capacity ; 
it  has  nothing  constant,  relatively  to  the  other 
distinctive  characters  of  the  groups  established 
among  the  conchifera  generally :  thus  it  either 
occurs  or  is  wanting  indifferently  among  the 
individual  members  of  the  dimyarian  and  mo- 
nomyarian  families. 


Fig.  347. 


The  stomach  (6,  Jig.  347,  d,fig.  348)  is   a 
membranous  pouch,   commonly  pear-shaped, 


CONCHIFERA. 


C9? 


sometimes  globular,  rarely  elongated  and 
narrow.  When  the  oesophagus  exists,  it  opens 
into  the  upper  part  of  the  stomach ;  but 
when  that  canal  is  absent,  the  mouth  termi- 
nates directly  in  the  stomach.  Examined 
internally,  the  stomach  presents  several  de- 
pressions irregularly  dispersed  over  its  surface, 
by  means  of  which  the  bile  is  brought  into 
its  cavity ;  it  is  on  this  account  that  these 
minute  depressions  have  received  the  name 
of  the  biliary  crypts.  The  intestine  (c,  jig. 
347,  e,  fig.  348)  arises  from  the  posterior 
wall  of  the  stomach,  and  a  very  singular  ap- 
paratus is  occasionally  found  in  its  vicinity 
(d,Jig.  347),  the  use  of  which  is  not  yet  de- 
termined. It  consists  of  a  small  appendage 
which  may  be  compared  to  the  vermiform 
process  of  the  ccecum  in  the  higher  animals ; 
it  communicates  with  the  stomach,  and  is  filled 
by  a  horny  process  or  stylet  of  different  lengths 
and  thickness,  according  to  the  genera  and 
species  examined.  The  anterior  extremity  of 
this  body  is  attached  to  the  parietes  of  the 
stomach  by  means  of  small  extremely  thin  and 
irregular  auricular  processes  (oreillettes).  It  is 
to  be  presumed  that  quantities  of  the  food  may 
fall  during  the  act  of  digestion  between  the 
parietes  of  the  stomach  and  the  horny  body,  by 
it  to  be  pressed  or  bruised  in  some  particular 
manner.  Yet  when  those  conchiferous  ani- 
mals which  are  furnished  with  the  apparatus 
just  mentioned,  are  examined  by  dissection, 
no  particle  of  food  is  found  in  such  a  position. 
We  may  therefore  be  allowed  to  conjecture 
that  this  part  accomplishes  some  other  purpose 
in  the  economy  of  the  conchifera.  Whatever 
this  may  be,  it  must,  we  should  imagine,  be 
connected  with  the  function  of  digestion. 

The  intestinal  canal  in  the  conchiferous 
Mollusca  is  generally  slender,  cylindrical,  and 
from  one  extremity  to  the  other  almost  always 
of  the  same  diameter.  After  having  made  a 
variable  number  of  convolutions  within  the 
substance  of  the  liver  and  the  ovary,  the  in- 
testine comes  into  relation  with  the  dorsal  and 
median  line  of  the  animal's  body.  It  con- 
tinues in  this  direction  to  the  posterior  extre- 
mity, there  to  terminate  in  the  anus  (e,Jig.  347, 
/,  jig.  348) ;  the  whole  of  this  dorsal  part  of 
the  intestine  is  named  rectum.  The  rectum  is 
generally  longer  in  the  Di  my  aria  than  in  the 
Monomyaria,  because  the  anus  is  found  above 
the  superior  adductor  muscle  in  the  former, 
whilst  in  the  Monomyaria  the  rectum  twists 
round  behind  the  central  muscle  to  terminate 
in  an  anus  which  floats  between  the  edges  of 
the  mantle. 

The  liver  (f,  jig.  347,  g,  fig.  348)  is  a 
bulky  organ  enveloping  the  stomach  and  part 
of  the  intestine.  It  pours  the  product  of  its 
secretion  directly  into  the  stomach  by  means 
of  the  biliary  crypts.  The  liver  alone  con- 
stitutes a  very  large  portion  of  the  visceral 
mass,  and  consequently  of  the  body  of  the 
animal ;  it  consists  of  a  great  number  of  fol- 
licles connected  together  by  means  of  lax  and 
extremely  delicate  cellular  membrane ;  this 
structure  renders  the  organ  very  easily  torn. 
We  shall  see  by-and-bye  that  it  is  traversed  in 


Fig.  348. 


the  greater  number  of  mollusks  by  several 
muscles  belonging  to  other  parts,  an  arrange- 
ment which  contributes  to  support  and  give  it 
greater  strength. 

The  exposition  which  has  now  been  given 
of  the  structure  of  the  organs  of  digestion, 
affords  a  ready  explanation  of  all  that  bears 
upon  this  function  in  the  conchiferous  mol- 
lusca.  These  animals  not  having  the  mouth 
armed  with  any  hard  part  are  unable  to  seize 
and  swallow  any  kind  of  solid  food,  so  that  in 
general  nothing  more  is  found  in  their  sto- 
machs than  segregated  particles,  proceeding 
without  doubt  from  the  decomposition  of 
aquatic  animals  and  plants.  The  lips,  and 
unquestionably  the  labial  palps  also,  are  de- 
stined to  give  the  animal  perception  of  the 
aliment  it  takes.  Once  in  the  stomach,  this 
aliment,  impregnated  with  bile  and  probably 
also  with  a  gastric  juice  secreted  by  the  lining 
membrane  of  this  pouch,  is  subjected  to  a 
first  digestive  elaboration ;  it  next  passes  the 
pylorus  when  it  exists,  and  then  traverses  the 
intestinal  canal  and  supplies  to  the  absorbent 
system  the  elements  necessary  to  the  nutrition 
of  the  animal. 

It  does  not  appear  that  there  is  any  par- 
ticular system  of  absorbent  vessels  in  the  con- 
chiferous Mollusca;  the  veins  perform  the 
office  of  absorbents,  and  they  transmit  with- 
out any  intermedium,  and  without  their  under- 

2z 


696 


CONCHIFERA. 


going  any  glandular  elaboration,  the  fluids  ab- 
sorbed to  the  general  current  of  the  circulation. 
After  having  thus  had  all  the  nutritious  ele- 
ments it  contains  abstracted,  the  alimentary 
mass,  having  reached  the  rectum,  there  com- 
monly presents  itself  under  the  form  of  minute 
globules ;  it  is  soon  afterwards  expelled  through 
the  anus. 

Organs  of  circulation. — The  organs  of  cir- 
culation in  the  acephalous  Mollusca  consist 
of  two  vascular  systems  forming  together  a 
simple  circuit,  namely,  a  ventricle  and  an 
arterial  system,  and  a  venous  system  and  two 
auricles.  The  ventricle  in  the  majority  of 
acephalous  mollusca  is  single,  symmetrical, 
situated  in  the  dorsal  median  line  of  the  body, 
and  rests  upon  the  rectum,  which  it  embraces 
in  its  evolution  (g,  Jig.  347,  h,  fig.  348)  on 
every  side  so  closely,  that  the  intestine  appears 
to  pass  through  it.  It  is  to  be  presumed, 
however,  that  the  intestine  does  not  pass  im- 
mediately athwart  the  heart,  but  that  this  canal 
is  only  embraced  so  intimately  by  the  central 
organ  of  the  circulation,  that  it  is  impossible  to 
-separate  without  tearing  them.  The  ventricle, 
which  is  regular  and  symmetrical  in  the  greater 
number  of  the  genera  (a,  jig,  349)  is  irregular 
and  unsymmetrical  in  the  Ostracean  family,  (a, 
Jig.  350).  It  is  generally  elongated  and  fusiform ; 


Figs.  349  &  350. 


its  parietes  are  thin,  formed  of  muscular  fibres 
variously  interlaced,  and  often  projecting  in- 
ternally. From  either  extremity  issues  one  of 
the  two  main  arteries  of  the  body,  the  one 
superior  giving  branches  to  the  whole  of  the 
-anterior  parts  of  the  animal ;  the  other  pos- 
terior supplying  branches  to  the  principal  vis- 


cera,— the  stomach,  liver,  intestinal  canal,  and 
ovary.  Many  superficial  branches  penetrate 
the  mantle,  and  may  be  observed  ramifying 
more  especially  upon  the  thicker  parts  which 
constitute  its  edges. 

When  the  back  of  the  animal  is  very  broad, 
and  as  a  necessary  consequence  of  this  struc- 
ture, the  branchiae  of  one  side  are  at  a  consi- 
derable distance  from  those  of  the  other  side, 
we  find,  as  among  the  Archidae,  that  there  are 
then  two  ventricles  (a,  a,  fig.  351 ,)  and  two  auri- 
cles (b,  b,  Jig.  351)  to  secure  the  perfect  per- 
formance of  the  important  business  of  circula- 
tion. This  interesting  modification  of  the  organs 
of  circulation  is  of  slight  significance  as  regards 
the  mere  results  of  the  function,  for  it  still  con- 
tinues no  more  than  a  simple  circuit,  exactly 
as  if  it  were  effected  by  a  single  ventricle. 

The  auricles  are  two  in  number  (6,  b, 
Jigs.  349  &  351,  «,  Jig.  348)  in  the  whole 
of  the  genera  of  Conchifera  except  those  of 
the  family  of  the  Ostracea,  in  which  there 
is  no  more  than  a  single  irregular  auricle 
(b,Jig.  350),  just  as  there  is  but  one  ventricle. 
The  most  general  figure  presented  by  the  au- 
ricles is  the  triangular.  They  communicate 
with  the  ventricle  by  one  of  the  angles  of  the 
triangles,  and  they  receive  the  blood  of  the 
branchiae  by  the  most  extensive  of  their  three 
sides.  These  organs  are  altogether  membra- 
nous; in  their  interior,  however,  we  discover, 
with  the  aid  of  the  magnifier,  a  great  number 
of  small  fibrous  fasciculi,  by  means  of  which 
the  regular  contraction  of  the  ventricles  appears 
to  be  effected. 

The  venous  system  is  of  very  considerable 
magnitude.  In  his  magnificent  work,  Poli* 
has  given  a  very  satisfactory  account  of  its 
anatomy.  It  is  more  particularly  remarkable 
in  the  Archidae,  the  Pinna,  &c.  It  is  destined 
to  receive  the  blood  of  the  general  circulation  ; 
it  is  also  destined  to  collect  the  whole  of  the 
fluids  absorbed,  and  to  direct  these  towards 
the  branchial  apparatus,  in  which  the  blood 
with  these  added  fluids  undergoes  a  fresh 
elaboration.  It  is  after  having  traversed  the 
branchial  vessels  (c,  r,c,  r,  Jig.  349,  351,  j, 
Jig.  348)  that  the  blood  revivified  is  carried  to- 
wards the  auricle  by  the  pulmonary  veins,  from 
whence  it  is  sent  to  the  ventricle,  and  by  it  forced 
anew  to  perform  the  round  of  the  arterial  cir- 
culation. 

The  blood  in  the  Conchiferous  mollusks  is 
colourless,  or  of  a  bluish  white,  very  different 
from  the  hue  it  presents  in  the  vertebrata ; 
it  is  but  slightly  viscid,  and  when  it  coagulates 
exhibits  but  a  very  small  quantity  of  crassa- 
mentum  or  solid  matter. 

Circulation  then  is  an  extremely  simple 
function  in  the  Conchiferous  mollusks:  an 
aortic  ventricle  gives  the  blood  impulse  enough 
to  carry  it  through  the  two  systems  of  vessels, 
to  expel  it  from  the  heart  and  to  bring  it  back 
again  to  the  auricle.  In  other  branchiferous 
animals,  the  auricle  is  sometimes  adapted  to 
give  the  blood  a  new  impulse  when  it  is  about 
to  pass  through  the  branchiae;  here,  on  the 

*  Testacea  Utriusque  Siciliae,  fol.  3  torn. 


CONCHIFERA. 

Fig.  351. 


699 


contrary,  the  auricles  do  not  receive  the  blood 
until  it  has  been  exposed  to  the  revivifying 
influence  of  the  organs  of  respiration. 

Of  the  organs  of  respiration. —  The  whole 
of  the  Conchiferbus  mollusks  respire  by 
means  of  branchiae  (e,  e,Jig.  346).  These  or- 
gans are  variously  disposed  according  to  the 
form  of  the  animal.  They  are  symmetrical ; 
and  in  almost  all  the  genera  there  are  two  on 
each  side.  The  branchiae  generally  present 
the  form  of  membranous  leaflets,  of  a  qua- 
drangular shape,  though  often  unequal.  They 
are  broad  and  short  when  the  animal  is  glo- 
bular, elongated  and  narrow  when  the  animal 
is  lengthened  in  its  general  form.  In  the 
greater  number  of  genera  the  branchiae  are 
formed  of  two  membranous  layers  or  laminae 
(a,  b,  Jig.  352)  within  the  substance  of  which 
the  branchial  vessels  descend  with  great  regu- 
larity. In  several  genera,  as  the  Archidae  and 
Pecten,  the  branchial  vessels,  instead  of  being 
connected  parallel  to  one  another  within  the 
thickness  of  a  common  membrane,  continue 
unconnected  through  their  entire  length,  and 
they  are  thus  formed  of  a  great  number  of 
extremely  delicate  filaments  attached  by  the 
base  within  a  membranous  pedicle,  in  which 
the  branchial  veins  pursue  their  way  towards 


Fig.  352. 


the  auricle.  In  a  great  many  families  and 
genera  the  branchiae  of  one  side  have  no  com- 
munication with  those  of  the  opposite  side ; 
in  some  others  however,  as  in  the  genus  Unio, 
the  four  branchial  laminae  meet  under  the  foot, 
and  the  whole  of  their  vessels  empty  them- 
selves into  a  venous  sinus  of  considerable 
size. 

2  z  2 


TOO 


CONCHIFERA. 


A  remarkable  phenomenon  is  observed  in  a 
great  many  of  the  Conchiferous  mollusks  :  the 
eggs  on  escaping  from  the  ovary,  instead  of 
being  cast  out  altogether,  are  deposited  between 
the  two  membranes  of  the  branchial  laminae, 
and  there  undergo  a  kind  of  incubation, 
during  which  they  acquire  a  considerable  size. 
In  some  genera,  such  as  the  Unio,  the  shell 
is  even  developed  within  the  egg  before  this  is 
cast  loose  from  the  branchiae,  and  this  circum- 
stance has  led  several  anatomists  to  mistake 
these  small  shells  for  parasites.  As  in  all  the 
other  animals  having  branchiae,  the  organs  of 
respiration  are  destined  to  restore  to  the  blood 
the  oxygen  which  it  had  lost  in  its  circulation 
through  the  body.  This  necessary  element  to 
the  maintenance  of  life  is  restored  to  it  during 
its  passage  through  an  organ  contrived  so  as  to 
bring  it  almost  into  contact  with  the  ambient 
fluid  in  which  a  considerable  quantity  of  atmo- 
spheric air,  and  consequently  of  oxygen,  is 
found  dissolved. 

Organs  of  generation. — The  organs  of  ge- 
neration are  of  extreme  simplicity  in  the  Con- 
chiferous mollusks.  They  consist  of  an  ovary 
included  in  the  visceral  mass.  Not  a  trace  of 
any  otheV  organ  of  generation  can  be  detected, 
and  the  Conchifera  must  therefore  be  allowed  to 
possess  what  has  been  called  sufficient  herma- 
phrodism,  generation  in  them  taking  place 
without  coition.  The  ovary  is  a  glandular 
mass  situated  at  the  superior  and  posterior  part 
of  the  body;  it  is  in  connexion  with  the  liver  ; 
and  it  often  receives  a  portion  of  the  intestine, 
if  it  happens  to  be  developed  laterally  between 
the  two  fleshy  laminae  which  form  the  walls  of 
the  foot.  In  the  siphoniferous  acepha!a  having 
the  foot  short  and  rudimentary,  the  ovary,  in 
its  state  of  complete  development,  forms  a  very 
great  part  of  the  abdominal  mass,  amid  which 
it  is  easily  distinguished  by  its  soft  consistency 
and  yellowish  white  colour.  In  those  acephala 
in  which  the  siphon  is  short  and  the  foot  well 
developed,  the  ovary  forms  a  mass  less  promi- 
nent at  the  superior  and  posterior  parts  of  the 
viscera.  In  the  Conchifera  monomyaria  the 
ovary  resting  upon  the  central  muscle  is  situated 
in  the  upper  and  posterior  part  of  the  body, 
and  in  its  state  of  development  constitutes  a 
whitish  mass  of  considerable  size,  which  is 
readily  seen  in  the  Ostracea  through  the  walls 
of  the  mantle.  This  ovary  occupies  the  whole 
superior  part  of  the  animal,  and  it  is  seen  de- 
scending along  the  lateral  and  posterior  parts 
when  the  animal  is  examined  at  the  time  of 
laying  its  eggs ;  a  rent  in  the  ovary  allows  a 
fluid  of  a  milk-white  colour  to  escape.  This 
fluid  under  the  microscope  is  seen  to  contain  a 
very  great  number  of  small  whitish  granules, 
each  of  which  is  an  egg  capable  of  reproducing 
an  individual  similar  to  that  from  which  it  de- 
rives its  origin. 

There  is  a  singular  genus  placed  by  the 
generality  of  writers  in  alliance  with  the 
Oyster,  and  designated  by  the  name  of 
Anomia,  in  which  the  ovary  forms  no  part  of 
the  common  mass  of  the  viscera,  but  extends 
between  the  two  walls  of  the  mantle,  which  it 


separates  in  proportion  as  it  increases  in  size. 
This  position  of  the  ovary  in  the  substance  of 
the  skin  is  analogous  to  what  is  observed  in  the 
Terebratulae,  in  which  the  ovary  is  divided  into 
four  segments  comprised  within  the  substance 
of  the  mantle  and  in  the  direction  of  the  prin- 
cipal branchial  vessels. 

Notwithstanding  the  minute  dissections 
which  have  been  made  of  the  acephalous 
mollusks,  there  are  a  great  many  in  which 
the  oviduct  remains  unknown.  In  two  of 
these  animals  in  which  it  has  been  sought 
for  in  vain,  it  has  yet  been  seen  running  to- 
wards the  middle  and  anterior  part  of  the 
branchiae,  and  opening  to  the  right  between  the 
folds  of  this  side.  It  is  not  yet  known  whether 
or  not  it  be  by  this  opening  that  the  ova  escape 
after  they  have  undergone  incubation  in  the 
branchiae,  or  whether  they  escape  by  the  edges 
of  these  organs. 

M.  Prevost  of  Geneva  has  made  some 
important  observations  on  the  generation  of 
the  Uniones,  which  appear  to  prove  that 
although  coitus  cannot  take  place  between 
the  acephala,  it  is  nevertheless  necessary  to 
their  propagation  that  a  certain  number  of  these 
animals  be  found  together  near  the  same  spot. 
From  these  experiments  we  may  infer  that  a 
fecundating  fluid  is  diffused  in  the  water  and 
absorbed  by  the  ovary,  which  is.  thus  fecun- 
dated without  the  contact  of  two  individuals. 
This  phenomenon  is  comparable  to  that  which 
we  know  takes  place  in  the  fecundation  of  the 
ova  of  fishes ;  these  are  deposited  by  the  female, 
and  afterwards  sprinkled  by  the  male,  who 
places  himself  above  them,  with  the  prolific 
fluid.  Before  adopting  definitively  the  results 
of  M.  Prevost's  experiments,  however,  it  were 
necessary  to  repeat  them  a  great  number  of 
times,  in  order  to  leave  no  doubts  on  this  ques- 
tion, so  interesting  to  the  naturalist  as  well  as 
to  the  physiologist,  touching  the  generation  of 
the  hermaphrodite  mollusca. 

The  number  of  eggs  extruded  by  each  in- 
dividual is  very  great,  and  explains  the  rapidity 
with  which  these  animals  are  propagated  in 
certain  seas,  and  the  production  by  accumulated 
generations  of  those  extensive  beds  of  shells 
which  are  so  frequently  found  covering  the  sur- 
face of  actually  existing  continents. 

Organs  of  motion. — The  organs  of  motion 
are  of  two  kinds :  one  is  destined  to  move  the 
two  valves  with  which  the  animal  is  covered ; 
the  other  is  peculiar  to  a  special  organ,  by 
means  of  which  the  animal  moves  its  whole 
body.  The  muscles  may  therefore  be  arranged 
into  two  classes  :  1st,  adductor  muscles  of  the 
valves ;  2d,  locomotory  muscles,  or  muscles 
proper  to  certain  organs.  Those  fleshy  and 
fibrous  fasciculi  attached  between  the  two 
shells,  and  which  by  their  contraction  approxi- 
mate and  close  these  two  shells,  are  denomina- 
ted the  adductor  muscles.  In  the  greater  num- 
ber of  the  conchiferous  mollusca,  two  of  these 
muscles  can  be  demonstrated,  the  one  anterior 
(c,Jig.  346;  A,  Jig.  347;  «,  Jig.  362)  situated 
in  front  of  the  oral  aperture,  and  the  other  pos- 
terior (f,Jig.  346;  i,  fig.  347',  b,  fig.  362). 


CONCHIFERA. 


701 


Lamarck  has  given  the  title  of  Di/nyaires  to  all 
the  mollusca  having  two  adductor  muscles,  a 
character  which  he  has  invested  with  a  consi- 
derable degree  of  importance,  because  it  is  con- 
stantly proclaimed  by  the  interiors  of  shells, 
upon  which  the  impression  left  by  these  mus- 
cles is  very  distinctly  seen  (a,  b,Jig.  367).  One 
of  these  muscles,  the  anterior,  diminishes  gra- 
dually as  we  descend  in  the  series  of  the  Con- 
chifera;  in  the  family  of  Mytilacea  it  only 
exists  in  a  rudimentary  state  (a,  jig.  353);  and 
after  these  it  disappears  entirely.  In  propor- 
tion as  the  anterior  muscle  disappears,  the  pos- 
terior one  increases  in  size,  and  approaches 
more  nearly  to  the  middle  of  the  valves.  When 
no  farther  trace  of  anterior  muscle  can  be  dis- 
covered, the  posterior  muscle  continues  singly 
(k,Jig.  348),  and  the  mollusca  having  a  single 
muscle,  very  distinct  from  the  former  which 
have  two,  have  received  the  name  of  Mono- 
myaires  from  M.  Lamarck. 

Poli,  however,  has  shewn  that  the  muscle  of 
the  Monomyaria  consists  in  reality  of  two  por- 
tions, readily  separable  from  one  another,  and 
even  differing  considerably  in  their  appearance. 
This  leads  us  to  presume,  with  every  show  of 
reason,  that  the  single  muscle  in  the  Mono- 
myaria is  the  result  of  the  approximation  of  the 
two  muscles,  which  are  parted  in  the  Dimyaria. 
This  fact  would  incline  us  to  regard  the  num- 
ber of  the  muscles  as  a  matter  of  but  small  im- 
portance in  the  classification  of  the  conchiferous 
mollusks,  and  we  may  suppose  that  it  was  with 
such  inductions  before  him  that  Cuvier  was 
led  to  attach  such  slight  significance  to  the 
division  of  these  animals  proposed  by  La- 
marck. 

The  organ  denominated  foot  in  the  acepha- 
lous mollusks  is  a  part  which  presents  very 
different  forms,  and  is  destined  to  locomotion. 
This  part  is  particularly  well  developed  among 
the  Dimyaria,  and  we  shall  pass  in  rapid  re- 
view its  most  general  features. 

The  foot  (by  fig.  346)  is  usually  situated  at 
the  anterior  and  middle  part  of  the  abdominal 
mass,  and  is  directed  forwards.  It  is  so  placed 
as  to  hide  the  mouth  in  a  deep  sinus  between 
its  base  and  the  anterior  adductor  muscle.  In 
those  conchiferous  mollusks  in  which  the  lobes 
of  the  mantle  are  united  through  a  great  por- 
tion of  their  circumference,  the  foot  is  com- 
monly very  small  and  merely  rudimentary  ;  it 
then  forms  a  kind  of  little  nipple  projecting 
from  about  the  middle  of  the  abdominal  mass, 
a  form  which  is  very  distinctly  seen  in  the 
Mya,  Saxicava,  &c.  In  others  of  these  mol- 
lusks the  foot,  more  anteriorly  situated,  is  ex- 
tremely short,  broadly  truncated,  and  similar  to 
a  cupping-glass ;  this  configuration  is  observed 
in  the  Pholadia.  In  proportion  as  the  foot  be- 
comes more  free,  the  lobes  of  the  mantle  are 
distinct  from  one  another,  the  foot  becomes 
flattened  and  elongated  in  the  form  of  the 
human  tongue,  and  is  subservient  to  motion 
by  digging  a  hole  or  furrow  in  the  sand  into 
which  the  animal  sinks.  This  form  of  the 
locomotory  organ  is  met  with  more  especially 
in  the  Tellina,  the  Donata,  and  a  very  great 


number  of  other  genera,  the  shells  of  which  are 
more  or  less  flattened.  Lamarck  had  attached 
some  consequence  to  the  shape  of  the  organ  of 
locomotion,  and  Goldfuss  has  proposed  a  clas- 
sification based  upon  the  modifications  pre- 
sented by  this  organ  ;  but  the  groups  establish- 
ed in  accordance  with  such  considerations  are 
in  reality  of  no  importance ;  the  several  forma 
proper  to  the  organ  pass  too  insensibly  one  into 
another  to  make  it  possible  to  say  where  one 
terminates  and  another  begins ;  the  boundary 
between  one  family  and  another,  with  a  fevr 
rare  exceptions,  is  altogether  indefinite.  In  the 
present  day,  consequently,  naturalists  no  longer 
admit  into  their  methods  of  arrangement  the 
groups  established  by  Lamarck  under  the 
names  of  Tcnuipeda,  Crassipeda,  &c. 

The  foot  exists  developed  in  a  greater  or  less 
degree  in  the  whole  of  the  Dimyaria.  If  in 
some  species  it  is  found  merely  rudimentary,  it 
is  yet  never  altogether  wanting  in  any  member 
of  this  first  division  of  the  Conchifera.  The 
organ  is  also  met  with  in  a  very  considerable 
number,  but  by  no  means  in  the  whole  of 
the  Monomyaria,  and  the  presence  or  absence 
of  the  foot  might  be  taken  as  the  basis  of  a 
division  of  this  great  family  into  two  series,  in 
the  one  of  which  the  foot  was  rudimentary  but 
present,  whilst  in  the  other  it  was  no  longer  to 
be  found. 

Whatever  the  form  of  the  locomotory  organ, 
and  whatever  the  degree  of  its  development,  it 
is  always  organized  in  the  same  manner.  It  is 
essentially  composed  of  several  planes  of  mus- 
cular fibres  (1,  2,  3)t/?g.  347),  which  by  their 
various  courses  and  interlacements  enable  it  to 
perform  a  great  variety  of  different  motions, 
either  in  part  or  as  a  whole.  When  the  foot  is 
short  or  vermiform,  its  mass  is  entirely  muscu- 
lar from  the  apex  to  the  base.  It  is  at  the  base 
that  the  fleshy  fibres  separate  into  two  fasciculi 
(4,  5,  Jig.  347),  which,  after  having  circum- 
scribed the  visceral  mass,  proceed  backwards, 
where  they  are  attached  to  each  valve  of  the 
shell  near  the  implantation  of  the  posterior  ad- 
ductor muscle  in  the  Dimyaria;  and  towards 
the  superior  part  of  the  valves,  and  occasion- 
ally in  the  interior  of  the  hook,  or  incurved 
part  of  the  shell  in  the  Monomyaria. 

In  the  Conchifera  denominated  Lamellipeds 
and  Crassipeds  by  Lamarck,  in  a  word,  in 
the  whole  of  the  Conchiferous  mollusks  in 
which  the  foot  constitutes  a  principal  part 
of  the  body,  this  organ  presents  remarkable 
differences  in  its  composition  and  its  rela- 
tions with  the  internal  organs.  It  is  then 
formed  of  two  lateral  planes  of  fibres,  uniting 
and  blending  together  near  the  free  edge. 
These  two  planes,  more  or  less  separate  ac- 
cording to  the  general  form  of  the  animal, 
have  between  them  an  internal  space,  within 
which  is  included  a  considerable  portion  of  the 
visceral  mass.  In  the  generality  of  conchife- 
rous mollusks  furnished  with  a  large  foot,  it  is 
here  that  a  portion  of  the  liver  is  situated,  the 
greater  part  of  the  intestinal  canal,  and  a 
notable  portion  of  the  ovary.  These  organs  are 
bound  down  in  the  place  they  occupy,  and  the 


702 


CONCHIFERA. 


parietes  of  the  foot  are  preserved  in  immediate 
communication  by  means  of  a  great  number  of 
small  muscles,  sometimes  straight,  sometimes 
oblique,  and  variously  interlaced,  to  which 
Poli  has  given  the  name  of  funicular  muscles 
(jtjt  fig-  347)-  They  are  particularly  conspi- 
cuous in  the  cylindrical  foot  of  the  Solens,  in 
the  flattened  foot  of  the  Tellinae,  and  of  the 
Uniones,  and  they  have  a  remarkable  arrange- 
ment in  that  of  the  Cardiae.  They  appear  to 
be  wanting  in  the  foot  of  those  Conchiferous 
mollusks  that  attach  themselves  by  means  of  a 
byssus.  In  them  the  foot  is  reduced  to  the 
functions  of  spinning  (de  filer)  the  threads  of 
the  byssus,  and  it  is  not  therefore  surprising 
that  its  organization  should  be  found  to  be 
peculiar.  Reduced  to  a  purely  rudimentary 
state,  the  foot  in  the  Monomyaria  (b,  fig.  348) 
appears  rather  as  an  appendage  to  the  mass 
of  the  viscera  than  as  their  defensive  envelope. 
The  muscular  fasciculi  that  terminate  it  pos- 
teriorly are  small;  they  pass  through  the  vis- 
ceral mass  to  be  attached  either  to  the  superior 
part  of  the  central  muscle,  or  within  the  in- 
terior of  the  hooks  or  beaks  of  the  shell. 
Almost  the  whole  of  the  Monomyaria  furnished 
with  a  foot,  have  a  byssus  also ;  to  this  rule 
there  are  indeed  a  small  number  of  exceptions, 
among  others  the  Limse. 

Up  to  the  present  time  the  faculty  of  pro- 
ducing a  byssus  is  not  known  to  belong  to 
any  other  class  of  animals,  and  it  is  limited 
to  a  few  only  of  the  Conchiferous  mollusks. 
Among  the  Dimyaria  the  genus  Byssomya  may 
be  quoted  as  an  example,  also  the  members  of 
the  family  of  the  Mytilacea ;  and,  if  the  horny 
plates  of  certain  Archse  be  likened  to  the 

Fig.  353. 


byssus,  it  would  also  be  necessary  to  include 
this  genus  in  the  group  of  byssiferous  Dimyaria. 
In  the  Monomyaria  provided  with  a  foot,  the 
whole  of  the  genera  are  byssiferous,  with  the 
exception  of  those  which  attach  themselves  im- 
mediately by  their  shell. 

The  byssus  f  6,  fig.  353)  is  a  bundle  of  horny 
or  silky  filaments,  of  different  degrees  of  fine- 
ness and  of  different  thicknesses,  and  flexible 
in  various  measures,  by  means  of  which  the 
animal  is,  as  it  were,  anchored  to  any  solid 
body  sunk  in  the  sea.  The  filaments,  for  the 
most  part  distinct  from  one  another,  are,  how- 
ever, occasionally  connected  into  a  single  mass 
of  a  subcylindrical  form,  and  terminated  by  a 
broad  expansion,  which  serves  as  the  point 
of  attachment.  This  disposition  is  to  be  ob- 
served in  the  Aviculse,  and  leads  to  the  belief 
that  the  horny  mass  of  certain  Archae  is  a  mere 
modification  of  the  byssus.  In  those  species  of 
which  a  byssus  is  formed  of  separate  filaments, 
these  are  all  seen  to  be  detached  from  a  com- 
mon pedicle  (c,fig.  353),  situated  at  the  infe- 
rior base  of  the  foot  (d,  fig.  353).  If  the 
byssus  be  examined  before  any  of  the  filaments 
are  torn,  it  is  easy  to  perceive  that  these  are 
attached  to  submarine  bodies  by  means  of  a 
small  disc-like  expansion  of  their  extremities, 
of  various  extent  according  to  the  genus  and 
species  (a,  a,  a,  fig.  354).  Attentive  examina- 
tion of  these  filaments  shews  that  they  are  of 
equal  thickness  through  their  entire  length,  and 
that  they  have  nothing  of  the  structure  of  the 
hair  of  the  higher  animals. 

Fig.  354. 


If  the  byssus  and  foot  of  a  byssiferous  mol- 
lusk  be  placed  under  a  powerful  lens,  the  last 
filaments  of  the  byssus  are  first  seen  to  be 
nearest  to  the  base  of  the  foot;  and  if  the  infe- 
rior edge  of  the  foot  be  inspected,  a  fissure  will 


CONCHIFERA. 


703 


be  found  running  completely  along  it,  at  the 
bottom  of  which  a  brownish  and  semi-corneous 
filament  is  often  to  be  perceived ;  this  is  neither 
more  nor  less  than  a  filament  of  the  byssus 
prepared  to  be  detached  by  the  animal,  in 
order  to  which  the  animal  stretches  forth  its 
foot  until  it  encounters  the  object  upon  which 
the  other  fibres  of  the  byssus  are  fixed  ;  to  this 
it  applies  the  point  of  the  foot,  which  then  se- 
cretes a  small  quantity  of  glutinous  matter, 
continuous  with  the  silky  filament  lying  along 
the  bottom  of  the  furrow  of  which  we  have 
spoken.  When  the  pasty  matter  has  acquired 
sufficient  consistency,  and  is  firmly  fixed  to  the 
stone  or  other  body  at  the  bottom,  the  animal 
retracts  its  foot,  and  in  doing  so  detaches  the 
new  fibre  to  the  base  of  the  pedicle.  The 
mode  in  which  the  filaments  of  the  byssus  are 
formed,  is  consequently  entirely  different  from 
that  in  which  hair  or  the  horns  of  the  higher 
animals  are  evolved,  and  it  is  easily  under- 
stood when  the  intimate  structure  of  the  foot  of 
the  byssiferous  mollusks  is  known,  when  we 
are  aware  that  this  organ  consists  in  its  centre 
of  a  pretty  considerable  fasciculus  of  parallel 
and  longitudinal  fibres.  By  a  faculty  peculiar 
to  the  class  of  animals  that  now  engages  our 
attention,  the  fibres  situated  at  the  bottom  of 
the  groove  of  the  foot  become  horny,  and  are 
detached  in  succession  in  the  form  of  threads 
as  they  become  consolidated.  Certain  genera 
are  celebrated  for  the  abundance  and  fineness 
of  the  byssus ;  that  of  the  Pinnae,  among  others, 
which  was  even  known  to  the  ancients,  may  be 
spun  into  threads  like  silk  or  wool,  and  may  be 
used  to  manufacture  tissues  of  an  unchangeable 
colour,  and  of  great  strength  and  durability. 

With  reference  to  form.,  the  foot  presents  a 
variety  of  interesting  modifications.  Some- 
times it  is  short  and  truncated,  as  in  the  genus 
Pholas;  sometimes  more  elongated,  but  still 
truncated  at  the  summit, 
as  in  certain  Razor-shells 
(Solen},  (a,  fig.  355)  ; 
in  which  the  edges  of 
the  truncation  are  regu- 
larly toothed.  A  few  of 
the  acephalous  mollusks 
have  the  foot  cylindrical 
(«,  Jig.  356),  as  the  So- 
lenes  ;  when  it  presents 
this  form,  the  organ  is 
generally  terminated  by 
a  kind  of  glutinous  point, 
or  disc,  which  enables 
the  animal  to  fix  itself  at 
different  heights  in  the 
deep  cylindrical  hole  it 
digs  for  itself  in  the 
sand.  The  foot,  which 
is  shaped  like  a  tongue, 
is  named  linguiform,  as 
in  the  Solen  strigilatus; 
it  is  claviform  when  it 
is  thicker  at  its  extremity 
than  at  its  base:  it  is 
found  of  this  shape  in 
certain  other  Solens.  The 


Fig.  355.    Fig.  356. 
*. 


foot  again  is  vermiform  when  it  is  very  slender 
and  much  elongated,  as  in  the  Loripes  and 
Lima.  When  it  is  thus  formed,  it  appears 
to  us  to  be  incapable  of  subserving  motion. 
In  a  considerable  number  of  species  the  foot 
is  conical,  as  in  the  Cockle,  (a,  Jig.  357); 
and  in  this  case  it  is  generally  folded  into 
two  nearly  equal  portions,  so  that  by  its  means 

Fig.  357. 


the  animal  can  leap  pretty  actively.  It  is  secu- 
riform when  its  free  edge  is  arched  like  the 
cutting  face  of  an  axe,  as  in  Petunculus,  («, 
Jig.  358).  When  it  presents  this  form  its  edge 

Fig.  358. 


is  generally  divided  into  two  lips,  which,  being 
separated,  present  with  some  degree  of  ac- 
curacy, although  much  contracted,  the  sem- 
blance of  the  locomotive  plane  of  certain  Gas- 
teropoda. When  this  structure  occurs,  the 

Fig.  359. 


foot  is  said  to  be  bifid,  as  in  Nucula,  Trigoniu. 
It  is  said  to  be  Jlattened  when  it  is  thin  and 
laterally  depressed,  as  in  Tellina  and  Donax ; 
to  conclude,  it  is  designated  as  bent  when  it 
consists  of  two  portions  connected  at  an  angle 
with  one  another  (b,  fig.  359),  of  which  the 
genera  Cardium,  Nucula,  and  Trigonia  present 
examples.  Various  other  modifications,  of  less 
importance  than  those  we  have  particularized, 


704 


CONCHIFERA. 


also  occur;  these  can  be  aptly  enough  alluded 
to  in  the  anatomical  description. 

From  what  has  now  been  said  it  is  easy  to 
understand  the  offices  performed  by  the  foot. 
In  the  lithophagous  and  xilophagous  Con- 
chifera,  the  foot,  reduced  to  its  rudimen- 
tary condition,  is  probably  without  any  par- 
ticular use,  unless  perhaps  it  be  among  the 
Pholades,  where,  being  in  the  form  of  a  sucker, 
it  may  enable  the  animal  to  fix  itself  to  the 
parietes  of  the  cavity  it  inhabits.  Among  the 
Conchiferous  mollusks  that  live  at  large,  the 
chief  use  of  the  foot  is  to  dig  a  furrow,  into 
which  the  animal  forces  itself  partially,  and 
then  advances  slowly  by  making  slight  see- 
saw or  balancing  motions,  a  circumstance  which 
has  led  Poli  to  designate  the  whole  class  of 
acephala  by  the  title  of  Mollusca  subsilentia. 
Several  of  these  Mollusks  not  only  make  use 
of  the  foot  in  the  way  we  have  just  mentioned, 
but  also  employ  it  as  a  means  of  executing 
sudden  and  rapid  motions,  true  leaps,  by 
which  they  are  enabled  to  change  their  place 
with  great  celerity.  It  is  of  course  unneces- 
sary to  say  that  in  those  genera  whose  shell  is 
attached  immediately  to  the  bodies  at  the  bot- 
tom of  the  sea  (Chama),  the  foot  is  of  no  use 
as  an  organ  of  locomotion  at  all  events.  In 
the  byssiferous  species,  again,  the  organ,-  al- 
though but  slightly  developed,  is  the  agent  in 
spinning  the  filaments  of  this  cable. 

Nervous  system. — Anatomists  were  long  ig- 
norant of  the  existence  of  a  nervous  system  in 
the  Conchiferous  mollusca.  Poli  first  disco- 
vered it  in  the  course  of  his  dissections,  whilst 
preparing  subjects  for  the  plates  of  his  magni- 
ficent work,  entitled,  Testacea  Utriusque  Sid- 
lite;  but  he  mistook  the  nervous  system,  occa- 
sionally of  considerable  magnitude,  for  one  of 
absorbent  or  lymphatic  vessels,  and  spoke  of  it 
under  the  name  of  lacteal  vessels.  In  a  very 
interesting  memoir,  Mangili  exposed  the  error 
which  Poli  had  committed,  and  rectified  it  by 
assigning  to  the  vasa  lactea  of  his  learned 
countryman  their  true  place  as  portions  of  the 
nervous  system. 

The  acephala  have  no  brain  properly  so 
called.  The  nervous  system  is  symmetrical  in 
the  Dimyaria,  but  loses  this  character  in  some 
measure  in  the  Monomyaria.  This  diversity 
in  the  nervous  system,  coinciding  with  the 
number  of  the  muscles,  gives  a  higher  value 
to  the  character  which  is  established  on  the 
existence  of  one  or  two  adductor  muscles.  In 
the  Dimyaria  we  find,  on  each  side  of  the 
mouth,  a  small  ganglion  above  the  oesophagus, 
towards  the  base  of  the  labial  palps  (1,1, 
Jig.  360).  Each  of  these  ganglions  is  of  an 
oval  or  sub-quadrangular  shape,  and  the  two 
are  connected  by  means  of  a  transverse  filament 
(2>  fig'  360)  running  across  or  over  the  O3so- 
phagus.  From  the  edges  of  the  ganglions 
many  filaments  arise,  some  of  which  on  the 
sides  descend  into  the  substance  of  the  labial 
palps  (3,  fig.  360);  others  anterior  are  distri- 
buted to  the  edges  of  the  mouth ;  and  others 
run  to  the  lateral  parts  of  the  anterior  adductor 
muscle,  gain  the  thick  portion  of  the  edge  of 


Fig.  360. 


Nervous  system  of  an  Unio. 


the  mantle,  and  detach  numerous  branches. 
From  the  posterior  edges  of  these  anterior 
ganglions  there  is  one,  and  occasionally  there 
are  two  nervous  branches  of  considerable  size 
sent  off  (4,  4,  fig.  360) ;  these  descend  along 
the  body  towards  the  base  of  the  branchiae, 
concealed  amidst  the  visceral  mass,  and  give 
off  filaments  in  their  course  to  the  neighbour- 
ing organs,  first  to  the  stomach,  then  to  the 
liver  and  heart,  and  next  to  the  ovary  and 
branchiae.  A  considerable  branch  descends  on 
each  side  of  the  foot,  and  is  expended  upon 
this  organ.  When  the  lateral  filaments  have 
arrived  opposite  to  the  posterior  adductor 
muscle,  they  advance  along  its  internal  sur- 
face, approach  one  another,  and  at  their  point 
of  junction  give  origin  to  one  or  two  ganglions 
of  different  sizes,  but  always  larger  than  the 
anterior  ganglions.  When  the  posterior  gan- 
glions are  some  way  apart,  a  neivous  filament 
always  connects  them.  It  is  from  these  pos- 
terior ganglions  that  the  nervous  cords  are 
detached,  the  branches  of  which  are  distri- 
buted to  the  whole  posterior  parts  of  the  ani- 
mal. Some  run  towards  the  anus,  others  to 
the  thin  portion  of  the  mantle,  and  a  consi- 
derable number  to  the  thickened  margin  of  the 
same  organ.  When  the  lobes  of  the  mantle 
are  conjoined  posteriorly,  and  are  continued 
from  this  part  by  means  of  siphons,  among 
the  nervous  branches  which  follow  the  thick- 
ened edge  of  the  mantle,  one  is  distinguished 
of  larger  size  than  the  others,  which  terminates 
at  the  point  of  commissure  in  a  small  ganglion. 
This  little  ganglion  is  not  met  with  in  the 
Dimyaria  without  a  siphon ;  neither  does  it 
appear  in  the  Monomyaria.  When  the  siphons 
occur,  however,  a  retractor  muscle,  peculiar  to 
them,  is  almost  invariably  found  also,  as  we 
have  already  seen.  When  these  two  parts 


CONCHIFERA. 


705 


exist,  nervous  branches  arc  likewise  discovered, 
destined  for  them,  one  for  each  of  the  retractor 
muscles,  and  one  for  each  of  the  siphons. 
The  posterior  part  of  the  nervous  system  of 
the  Dimyaria  is  so  considerable  in  comparison 
with  the  anterior  part,  that  some  anatomists 
have  maintained  that  the  title  of  brain  should 
be  given  to  the  posterior  ganglions,  conceiving 
them  to  be  of  much  greater  consequence  in 
the  organization  of  these  animals,  and  of  more 
avail  in  regulating  their  functions  than  the 
anterior  ones. 

In  the  Monomyaria  the  nervous  system  is  in 
general  less  perfectly  developed   than  in  the 
Dimyaria.     It  is  not  quite  symmetrical,  and 
the  posterior  are  not  larger  than  the  anterior 
ganglions.     The  nervous  cords,  too,  are  much 
more  slender,  and  not  nearly  so  easy  of  de- 
monstration as  in  the  Dimyaria;   it  was  not 
without  difficulty  that  we  discovered  them  in 
the  common  Oyster,  the  Pecten  and  the  Spon- 
dylus.    Poli  has  said  nothing  upon  the  nervous 
system  of  these  genera.     Our  own  researches 
in  quest  of  it  were  perfectly  fruitless  at  first ; 
but  having  bethought  us  that  in  the  Dimyaria 
the  nervous  cords"  of  the   labial   palps  were 
always  to  be  discovered  without  difficulty,  we 
sought  for  the  same  filaments  in  the  Mono- 
myaria, and  were  lucky  enough  to  find  them ; 
these  led  us  by-and-bye  to  the  anterior  gan- 
glions, and  by  degrees  to  the  detection  of  the 
entire  nervous  system.     The  anterior  ganglions 
in  the  Monomyaria  are  extremely  small ;  they 
send  a  principal  filament  to  each  of  the  palps; 
a  cord  proceeds  from  them  to  the  anterior  part 
of  the  mantle  which  covers  the  mouth  ;  another 
runs  from  the  ganglion  of  one  side  to  that  of 
the  other,  passing  above  the  oesophagus ;  and 
from  the  posterior  angle  several  branches  are 
detached  to  the  liver,   the  stomach,  and  the 
branchiae.      Among   these   there   is   one,  and 
sometimes  two,  which,  resting  on  the  internal 
aspect  of  the  central  muscle,  bend  obliquely 
over  its  surface,  and  finally  unite  occasionally 
to  form  a  small  posterior  ganglion.     This  gan- 
glion sends  branches  to  the  heart,  to  the  ovary, 
and  to  the  posterior  parts  of  the  mantle.     The 
parallel  cords  traverse  the  thin  part  of  the  man- 
tle, sometimes  radiating  in  a  slight  degree,  and 
divide  into  numerous  branches  within  its  thick 
margin  and  the  tentacular  ciliary  processes  that 
fringe  it.    There  is  one  among  the  monomyary 
genera,  the  nervous  system  of  which  we  have 
not  been  able  to  study  with  due  attention;  this 
is  the  genus  Lima.    From  what  we  have  seen 
of  it,  however,  it  would  appear  that  the  ner- 
vous system  in   this   genus  is  every  way  as 
perfectly  symmetrical  as  in  the  Dimyaria.    But 
before  admitting  this  as  a  fact  definitively,  it 
were  necessary  to  have  verified  its  accuracy  at 
least  several  times,  which  we  have  as  yet  had 
no  opportunity  of  doing. 

When  we  consider  the  great  simplicity  of 
the  nervous  system  of  the  acephalous  mol- 
lusca,  we  can  only  conceive  these  animals 
endowed  with  sensibilities  extremely  obscure, 
and  with  instincts  extremely  limited.  No 
especial  organ  of  sense  can  be  detected  among 


them,  unless  perhaps  it  be  that  of  touch,  which 
appears  to  reside  in  every  part  of  the  body  and 
of  the  mantle,  and  probably  also  the  sense  of 
taste,  of  which  in  all  likelihood  the  maxillary 
palps  are  the  organ.     The  manner  of  existence 
of  these  animals  is  in  perfect  accordance  with 
the  great  simplicity  of  their  nervous  system. 
Many  genera  live  attached  to  submarine  ob- 
jects, either  by  the  shell  immediately  or  by 
means  of  a  byssus,  taking  no  pains  to  avoid  or 
to  protect  themselves  from  danger,  and  giving 
no  sign  of  existence  but  by  opening  and  shut- 
ting their  shells :   they  shut  them  when  any 
foreign    body   comes    in    contact  with    their 
mantle ;    and   they  open  them  to   admit  the 
water  which  brings  suspended  in  it  the  nutri- 
tious particles  which  they  seize  upon  for  their 
subsistence,  and  which  is  in  itself  necessary 
for  the  purposes  of  respiration.     Among  the 
acephalous  mollusca  which  are  not  fixed  in  the 
manner  of  those  now  mentioned,  those  which 
have  no  siphon,  or  which-  have  this  part  very 
short,  live  at  the  bottom  of  the  sea,  in  spots 
covered  with  sand  or  mud,  amidst  which  they 
burrow   by   means   of   the  foot,   and   support 
themselves  in  an  oblique  position  by  resting 
upon  the  half-open  valves  of  their  shell.     The 
acephalous  mollusca  again,  which  are  furnished 
with  a  siphon,  almost  all  bury  themselves  more 
or  less  deeply  amid  the  sand  or  the  mud  of  the 
bottom,  contenting  themselves  with  an  ascend- 
ing or  a  descending  motion,  the  latter  sufficient 
in  the  moment  of  danger  to  gain  the  limits  of 
their  retreat,    the   former  to   enable  them  to 
protrude   the   free   extremity  of  their   siphon 
when   they   would    establish    the    current  of 
water  necessary  to  their  nutrition  and   respi- 
ration.    It  is  easy  to  imagine  that  among  ani- 
mals whose  functions  of  external  relation  are 
so  limited,  the  nervous  system  must  continue 
extremely  simple,  a  fact  which  could  in  some 
measure  be  predicated  from  observation  of  the 
habits  of  the  extensive  class  whose  structure 
and  economy  we  are  now  engaged  in  consi- 
dering. 

Of  the  skin  and  its  appendages. —  The 
mantle. — The  acephalous  mollusca  arc  enve- 
loped by  two  very  thin  fleshy  laminae,  which 
are  seen  covering  or  closely  applied  to  the 
whole  of  the  inner  surface  of  the  shell ;  this  is 
the  part  to  which  the  name  of  mantle  has  been 
given  (c,  Jig.  359 ;  a,  a,  fg.  360).  This  name 
has  been  very  appropriately  given  to  this  cuta- 
neous envelope,  for  it  appears  to  be  applied 
over  the  back  of  the  animal,  and  to  be  extended 
over  the  lateral  parts,  to  meet  by  its  edges 
along  the  anterior  middle  aspect  of  the  body. 
The  mantle  is  composed  of  two  parts  generally 
equal,  or  nearly  equal,  each  of  which  has  been 
designated  one  of  its  lobes.  In  the  natural 
position  of  the  animal,  one  of  these  lobes  is  in 
relation  with  its  right  side,  the  other  in  relation 
with  its  left  side ;  they  adhere  intimately  to  the 
superior  and  posterior  part  of  the  body ;  they 
become  free  at  the  origin  of  the  branchiae,  and 
form  around  the  whole  inferior  part  of  the 
animal  a  cavity  of  various  dimensions,  within 
which  the  abdominal  mass,  the  foot,  and  the 


706 


CONCHIFERA. 


branchiae  are  included.  It  is  in  this  palleal 
sac  that  the  animal  establishes  a  current  of 
water,  destined  to  minister  to  the  function  of 
respiration,  and  to  carry  towards  the  mouth  the 
alimentary  particles  with  which  it  is  fed.  The 
median  parts  of  the  lobes  of  the  mantle  are  ex- 
tremely thin  and  transparent,  and  a  great 
number  of  vessels  (c,  Jig.  362),  and  a  few 
nervous  filaments  (7,  8,  Jig.  360)  are  perceived 
ramifying  through  their  substance,  and  running 
towards  the  anterior  and  inferior  edges.  These 
edges,  which  extend  as  far  as  those  of  the  shell, 
are  thickened,  and  it  is  at  the  point  where  the 
thickening  begins  that  the  mantle  adheres  to  the 
shell  by  means  of  a  great  number  of  minute 
muscles  (/,  I,  jig.  347;  d,Jig.  362),  which  leave 
a  linear  impression  upon  it.  The  thickening  of 
the  edges  of  the  mantle  is  owing  to  the  pre- 
sence of  a  great  quantity  of  muscular  fibres,  fre- 
quently to  several  rows  of  contractile  tentacular 
cilia  (m,m,  Jig.  347;  e,  Jig.  361  &  362);  and, 
lastly,  to  that  of  an  organ,  which  is  the  secerning 
apparatus  of  the  shell.  The  muscular  fibres  are 


Fig.  361. 


Contractile  cilia  magnified. 

distributed  some  to  the  edges  of  the  mantle, 
and  others  to  the  tentacula  with  which  it  is 
fringed.  The  whole  of  these  parts  are  extremely 
retractile,  and  are  endowed  with  such  sensi- 
bility that  the  slightest  contact  is  perceived,  as 
is  evinced  by  their  instantaneous  contraction. 

Zoologists  have  taken  advantage  of  certain 
modifications  in  the  lobes  of  the  mantle  to 
establish  divisions  in  their  methodical  arrange- 
ments of  the  conchifera.  This  artificial  means 
is  sufficiently  convenient,  inasmuch  as  no 
anatomical  inquiries  are  necessary  in  order  to 
get  at  the  distinguishing  characters  which  these 
modifications  supply.  Latreille,  in  his  *  Fa- 
milies du  Regne  Animal,'  as  well  as  other 
zoologists,  have  also  made  use  of  the  conjunc- 
tion or  disunion  of  the  lobes  of  the  mantle  to 
establish  the  principal  divisions  of  their  classifi- 
cation ;  but  they  have  perhaps  given  too  much 
consequence  to  these  characters,  inasmuch  as 
they  bear  no  relation  to  the  number  of  the 
muscles.  Nevertheless,  none  of  the  Mono- 
myaria  has  yet  been  found  which  presents 
the  lobes  of  the  mantle  conjoined,  whilst  the 
Dimyaria  exhibit  the  two  modifications  which 
we  have  had  occasion  .to  mention,  and  which 
gives  an  opportunity  to  divide  them  into  two 
grand  series,  the  first  comprising  the  whole  of 
the  Dimyaria  whose  mantles  are  united,  the 
second  all  those  whose  mantles  are  open,  or 


unconnected  one  lobe  with  another.  The  con- 
chiferous  Dimyaria  which  exhibit  the  lobes  of 
the  mantle  united  are  modified  in  this  respect 
in  a  remarkable  manner,  a  circumstance  which 
induces  us  to  enter  somewhat  in  detail  into 
this  part  of  the  anatomy  of  the  conchifera. 

In  making  the  series  of  acephalous  mol- 
lusca  commence  with  those  which  have  the 
lobes  of  the  mantle  completely  distinct,  we 
may  place  near  them  certain  genera  in  which 
the  branchiae,  conjoined  in  their  posterior  parts, 
form  a  kind  of  canal,  within  which  the  anus 
proceeds  to  terminate.  This  conjunction  of  the 
branchiae,  extending  as  far  as  the  edge  of  the 
mantle,  forms  a  kind  of  band  towards  the  pos- 
terior commissure;  but,  notwithstanding  this, 
it  may  still  be  said  that  these  animals  have  the 
lobes  of  the  mantle  altogether  unconnected 
(Unio)  (Jig.  360)  ;  in  other  genera  which  have 
been  held  allied  to  this,  the  posterior  band  is 
not  found,  and  already  the  lobes  of  the  mantle 
appear  united  in  the  posterior  part,  to  a  very 
small  extent,  leaving  a  particular  perforation 
for  the  anus.  The  mantle  still  continues  open 
in  its  circumference  (Mytilus).  By-and-by 
neighbouring  genera,  and  even  particular  spe- 
cies of  the  same  genus,  instead  of  a  single  per- 
foration, present  two  (J\  g,  Jig.  362);  the 
second  is  destined  to  carry  the  water  directly 
upon  the  branchiae.  When  these  two  perfo- 
rations have  the  faculty  of  being  projected 
beyond  the  shell  in  the  form  of  fleshy  and  con- 
tractile tubes  of  various  lengths,  they  have  re- 
ceived the  special  denomination  of  siphons; 
and  the  term  perforation  has  been  reserved  to 
be  applied  to  the  holes  of  the  mantle,  which 
never  pass  the  edges  of  the  shell. 

When  the  two  siphons  begin  to  appear,  the 
lobes  of  the  mantle  still  continue  disjoined  in  a 
portion  of  their  circumference;  and  this  opening 
(b,  b,  Jig.  356,  h,  Jig.  362),  is  destined  for  the 
passage  of  the  foot. 

Fig.  362. 


In  proportion  as  the  foot  is  modified  in  its 
form,  in  proportion  as  it  becomes  more  rudi- 
mentary, the  two  lobes  of  the  mantle  are  ob- 
served in  the  succession  of  genera  to  become 
more  and  more  extensively  united,  and  it  hap- 
pens at  length  that  in  certain  genera  (Mya, 
Saxicava,  &c.)  a  very  minute  submedian  or 
anterior  perforation,  corresponding  to  the  rudi- 
mentary foot,  is  all  that  remains  of  separation 


CONCHIFERA. 


707 


between  them.  It  is  a  circumstance  worthy  of 
remark  that  the  siphons  are  observed  to  be- 
come elongated  and  thickened  in  proportion 
as  the  lobes  of  the  mantle  are  more  extensively 
united.  This  circumstance,  however,  is  only 
true  in  a  general  way,  for  it  would  be  easy  to 
quote  many  striking  exceptions  to  it. 

2.  Siphons. — We  have  already  had  occasion 
to  see  the  siphons  commence  in  certain  genera 
by  simple  perforations ;  they  increase  in  length 
in  the  succession  of  genera ;  and  in  a  certain 
number  they  always  continue  unconnected 
through  their  entire  extent  (g,  h,  Jig.  346  ;  b, 
c,  fig.  355).  In  other  genera,  however,  the 
siphons  are  seen  at  first  united  towards  their 
base,  then  conjoined  nearly  to  the  middle,  co- 
hering almost  to  their  ends,  and  finally  blended 
through  their  whole  length,  so  as  to  form  a 
single  elongated  subcylindrical  fleshy  mass, 
pierced  through  its  entire  length  by  the  canals 
of  the  two  siphons,  one  of  smaller  size,  situ- 
ated superiorly  for  the  anus,  the  other  larger, 
situated  under  the  former,  and  destined  to 
transmit  the  water  to  the  branchiae.  Whether 
connected  or  not,  the  superior  siphon  is  always 
characterized  as  the  anal,  the  inferior  as  the 
branchial  siphon. 

The  structure  of  the  siphons  is  entirely  mus- 
cular, so  that  their  free  extremities  are  capable 
of  contracting  and  of  being  elongated  to  a 
very  considerable  degree.  They  are  beset 
around  their  external  orifices  with  a  great 
number  of  papillae,  (n,  o,Jig.  347),  occasionally 
truncated  at  their  extremities  and  of  exquisite 
sensibility.  The  water  has  to  pass  over  these 
papillae  before  it  can  enter  the  mantle,  and  un- 
doubtedly they  apprise  the  animal  of  the  pre- 
sence of  every  foreign  body  that  might  injure 
it.  In  a  few  genera  the  siphons  contract  by 
means  of  their  component  muscular  fibres; 
but  in  the  greater  number  they  have  a  parti- 
cular retractor  muscle  running  on  each  side  of 
the  animal,  and  in  relation,  in  point  of  mag- 
nitude, &c.  with  the  length  and  degree  of  con- 
tractility possessed  by  the  siphons  (p,Jig.  347). 
The  existence  of  this  muscle,  and  consequently 
of  siphons,  is  manifested  on  the  interior  of  the 
shell  by  a  posterior  sinuous  furrow  of  various 
depth,  and  indicating  upon  a  narrow  line  the 
point  of  implantation  of  the  retractor  muscle  of 
the  siphons. 

In  some  of  the  acephalous  mollusks  the 
siphons  are  too  large  to  be  received  within 
cover  of  the  shell,  in  which  case  the  retractor 
muscle  is  generally  small,  inasmuch  as  it  is 
then  of  little  use  (Mya,  Glycimeris);  but  in 
those  species  in  which  the  siphons  are  of  mid- 
dling size,  or  not  so  large  as  to  be  incapable 
of  entering  the  shell,  the  retractile  muscle  is 
of  considerable  size  and  power  (Tellina, 
Psammobia). 

3.  The  shell. — The  lobes  of  the  mantle 
appear  to  be  the  efficient  parts  in  determining 
the  form  of  the  shell,  and  it  is  by  their  thick 
edges  that  this  covering  is  in  great  part  secreted. 
The  whole  of  the  Conchiferous  acephala,without 
exception,  are  included  within  a  bivalve  shell, 
the  two  parts  of  which  are  joined  by  a  point  in 
their  upper  edge,  to  which  the  title  of  hinge 


has  been  given  by  naturalists,  and  very  pro- 
perly, because  it  is  in  truth  upon  it  that  the 
motions  of  the  valves  take  place. 

General  structure. — When  examined  with 
due  attention,  the  shell  is  found  to  be  composed 
of  two  kinds  of  laminae  very  distinct  from  one 
another  (a,  b,  Jig.  363) ;  the  one,  secreted  from 
within  outwards  by  the  edges  of  the  mantle, 
present  themselves  under  the  form  of  greatly 
elongated  cones,  the  thick  parts  of  which  are 
turned  towards  the  outer  surface  («,  c,  c, 
Jig.  363) ;  the  other,  in  parallel  layers,  secreted 
by  the  central  and  posterior  parts 
Fig.  363.  of  the  mantle,  line  the  interior  of 
the  shell,  and  in  many  species  at 
length  fill  up  the  cavity  of  the 
hooks.  These  two  layers  of  the 
shell  are  frequently  found  in  cer- 
tain fossil  species  almost  com- 
pletely separated  from  one  an- 
other. At  other  times  the  inner 
layer  is  seen  to  have  been  dissolv- 
ed away,  whilst  the  external  one 
continues  without  appearing  to 
have  undergone  any  great  change. 
It  is  in  the  genera  Chama,  My- 
tiluSj  Pinna,  Spondylus,  more  es- 
pecially that  the  two  laminae  of 
which  a  bivalve  shell  is  formed  can 
be  studied  to  greatest  advantage, 
and  this  study  is  of  importance 
as  leading  to  a  more  accurate  knowledge  of 
certain  fossil  genera,  in  regard  to  the  charac- 
ter of  which  some  uncertainty  has  always  pre- 
vailed, by  reason  of  one  of  the  constituent 
portions  of  their  shell  always  being  found  dis- 
solved, as  in  Patillus.  In  some  genera  the  ex- 
ternal layer  is  very  readily  distinguished,  from 
having  a  fibrous  structure  (a,  a,  Jig.  369),  a 
structure  observed  more  especially  in  the 
shells  of  the  Pinna  family  and  those  of  the 
Malleacea.  The  two  layers  of  the  shell  are  in 
the  inverse  ratio  of  one  another  in  point  of 
thickness:  the  external  layer,  extremely  thin 
towards  the  hook,  increases  continually  towards 
the  edges,  whilst  the  inner  layer,  thick  at  the 
hook,  becomes  thinner  and  thinner  as  it  ap- 
proaches the  edges,  around  which  it  is  usually 
exceeded  a  little  by  the  outer  layer.  A  fact 
well  deserving  of  attention  is  this : — that  the 
muscular  impressions  and  the  whole  articular 
aspect  of  the  hinge  are  formed  in  the  substance 
of  the  inner  layer  of  the  shell,  and  these  parts, 
of  so  much  consequence,  do  not  leave  a  trace 
upon  the  external  layer  when  this  alone  is  pre- 
served. It  is  only  from  having  neglected  to  study 
the  structure  of  the  shell  with  sufficient  attention 
that  naturalists  have  found  themselves  at  a  loss 
to  discover  the  true  characters  of  certain  fossil 
genera,  as  Podopsis,  Spherulitcs,  which,  in 
consequence  of  their  position  in  porous  chalky 
beds,  never  occur  with  more  than  the  outer 
layer  of  their  shell  in  a  good  state  of  preser- 
vation. 

The  hinge.— The  part  of  the  edge  of  a  shell 
by  which  the  two  valves  are  conjoined,  is,  as 
we  have  already  had  occasion  to  state,  deno^ 
minated  the  hinge.  This  part  is  entirely  formed 
by  the  inner  layer  of  the  shell.  The  part  of 


708 


CONCHIFERA. 


the  shell,  of  various  length  and  thickness,  upon 
which  the  hinge  occurs,  is  called  its  cardinal 
edge.  In  the  hinge  two  structures  are  appa- 
rent :  1st,  an  elastic  ligament,  the  position  of 
which  is  variable ;  2d,  projections  and  corres- 
ponding cavities  on  either  valve,  destined  un- 
doubtedly to  give  additional  strength  to  their 
union. 

1.  The  ligament. — The  ligaments  of  bivalve 
shells  are  distinguished  into  two  kinds,  accord- 
ing to  their  structure  and  their  position :  they 
are  internal  when  they  are  completely  hidden 
by  the  cardinal  edge  of  the  shell;  they  are 
external  when  they  appear  on  the  outside  be- 
yond this  edge.  The  internal  ligament  is  com- 
posed of  a  great  number  of  highly  elastic 
fibres,  parallel  to  one  another,  and  perpendi- 
cular to  the  valves  they  connect.  They  are 
secreted  by  a  lamina  of  the  mantle,  projecting 
upon  the  back  of  the  animal,  and  penetrating 
between  the  edges  of  the  two  shells.  The 
fibres  of  the  ligament  secreted  when  the  shell 
is  partially  open,  are  of  too  great  length  when 
it  is  shut,  so  that  when  the  valves  are  ap- 
proximated to  one  another  these  fibres  are 
forcibly  compressed,  and  their  elasticity  is 
brought  into  play,  by  which  it  is  only  necessary 
for  the  animal  to  relax  its  adductor  muscles  in 
order  to  have  the  fibres  of  the  ligament,  in 
their  effort  to  regain  their  natural  length,  force 
the  valves  apart  from  one  another  to  a  deter- 
minate extent.  When  the  ligament  is  external, 
it  rests  upon  the  prominent  parts  of  the  cardinal 
edge,  parts  to  which  the  title  of  nympha  has 
been  given  (a,  a,  fig.  365).  When  the  ligament 
is  of  this  kind,  it  consists  of  two  distinct 
layers,  one  external,  thin,  and  very  strong, 
composed  of  transverse  fibres,  which  extend 
from  one  nympha  to  the  other,  and  are  strongly 
inserted  within  a  groove  hollowed  out  of  the 
base  of  each  of  them.  The  other  portion  of 
the  external  ligament  is  of  precisely  the  same 
structure  as  that  of  internal  ligiments,  and  is 
comprised  between  the  nymphae  and  the  outer 
layer,  of  which  we  have  just  made  mention. 
The  action  of  this  ligament  is  also  precisely 
the  same  :  it  forces  the  valves  apart  when  the 
animal  ceases  to  maintain  its  adductor  muscles 
in  a  state  of  contraction. 

In  the  extensive  series  of  Conchiferous  mol- 
lusks,  some  modifications,  as  might  have  been 
anticipated,  are  met  with  in  the  conformation 
of  the  ligament,  external  as  well  as  internal. 
If  many  members  of  the  family  of  the  Dimy- 
aria  be  examined,  the  ligament,  very  prominent 
outwards,  will  be  seen  bearing  upon  nymphae 
more  prominent  externally  than  the  cardinal 
edges,  but  contracting  gradually  under  this 
edge  in  proportion  as  the  nympha?  become 
shorter,  until  in  some  species  we  find  that, 
still  preserving  the  structure  of  the  external 
ligament,  the  whole  of  this  apparatus  is' never- 
theless entirely  hidden  under  tfie  superior  edge 
of  the  shell.  This  point  attained,  the  external 
ligament  alters  by  insensible  degrees  into  a 
ligament  completely  internal ;  that  is  to  say, 
the  exterior  fibrous  layer  diminishes  gradually, 
and  at  length  disappears  entirely  when  the 
ligament  is  much  developed  upon  certain  in- 


ternal parts  of  the  hinge.  Our  own  opinion  is, 
that  the  ligament  is  internal  when  the  nymphae, 
having  undergone  certain  modifications,  have 
been  transferred  to  the  interior,  and  have  as- 
sumed the  form  of  acetabula.  The  ligament 
is  sub-internal  when  the  nymphre,  of  less 
depth,  still  show  a  portion  of  the  ligament 
externally;  finally  the  ligament  is  external 
when  the  nymphae  are  situated  towards  the 
upper  edge  of  the  shell.  This  displacement 
of  the  ligament,  and  of  the  solid  part  which 
gives  it  insertion,  is  very  well  seen  in  the 
succession  of  the  following  genera :  Solen, 
Panopus,  Thracia,  Calcinella,  Amphidesma, 
Lutraria,  Mactra,  Mya,  Crassatella. 

In  those  shells  in  which  the  beaks  or  hooks  are 
of  great  size,  and  spirally  turned  to  one  side, 
the  ligament,  in  keeping  pace  with  the  growth 
of  the  covering,  bifurcates  at  its  anterior  part, 
and  this  bifurcated  part  then  becomes  useless. 
This  circumstance  is  particularly  remarked  in 
the  Isocardium  and  the  Chama.  The  ligament 
also  presents  a  very  remarkable  peculiarity  in 
the  three  genera  of  the  Area  family.  The 
superior  surface  of  the  hooks  in  these  genera 
(Area,  Pectunculus,  Cucullcea)  is  of  greater 
or  less  breadth,  flattened,  triangular,  some- 
times furrowed,  and  has  a  thin  ligament,  re- 
sembling an  elastic  web,  strongly  attached 
to  it. 

The  ligament  in  the  greater  number  of  the 
genera  of  the  Monomyaria  is  situated  within  a 
triangular  groove  or  depression  of  a  breadth 
corresponding  to  its  dimensions.  In  one  fa- 
mily, that,  namely,  of  the  Malleacea  of  La- 
marck, several  genera  (Perna,  Crenatula), 
instead  of  having  a  single  ligament,  have  a 
regular  series  of  fossiculae,  in  each  of  which  a 
ligament  is  implanted. 

Cardinal  edge. — The  cardinal  edge  presents 
a  great  number  of  modifications.  Sometimes 
it  is  simple,  and  of  various  degrees  of  thick- 
ness, in  which  case  the  hinge  is  said  not  to  be 
articulated ;  sometimes  it  presents  projections 
and  reciprocal  cavities,  in  which  case  the  hingn 
is  said  to  be  toothed  or  articulated  upon  the 
cardinal  edge.  These  projections  and  hollows 
are  remarkably  regular  in  their  formation,  and 
every  change  in  their  appearance  commonly 
coincides  with  one  of  greater  moment  in  the 
organization  of  the  animal.  This  remarkable 
coincidence,  to  which  only  a  very  few  exceptions 
are  yet  known,  has  led  conchologists  to  attach 
great  value  to  the  characters  derivable  from  the 
hinge,  and  Lamarck,  among  others,  has  grouped 
several  families  and  a  great  number  of  genera 
after  them.  We  believe,  with  this  celebrated 
naturalist,  that  the  hinge  supplies  excellent 
characters  for  the  distinction  both  of  families 
and  genera,  but  we  have  been  led  to  this  con- 
clusion by  viewing  the  subject  in  a  different 
point  of  view  from  that  taken  by  Lamarck. 

Every  conchologist  knows  the  interesting 
genus  denominated  Pfwlas.  In  the  interior  of 
the  valves  of  this  genus  there  always  exist 
two  kinds  of  large  curved  processes,  extend- 
ing from  the  interior  summit  of  the  hooks 
(«,  Jig..  364),  and  advancing  nearly  to  the 
middle  of  the  valves.  According  to  our  views 


CONCHIFERA. 


709 


Fig.  364. 


Pholas. 


Petricola. 


these  appendages  are  the  first 
parts  of  the  cardinal  teeth.  There 
is  one  fact  which  deserves  to 
be  insisted  on  in  connexion  with 
this  genus ;  it  is  that  there  are 
no  ligaments  found,  and  that 
the  cardinal  edge,  folded  in 
upon  itself  (rentre  sur  lui- 
rnn/te),  is  not  flattened  and 
placed  in  the  same  manner  as  in 
the  other  conchifera.  Another 
circumstance  of  equal  impor- 
tance to  be  mentioned  is  that 
the  processes,  of  which  we  have 
just  spoken,  are  buried  in  the 
substance  of  the  animal,  and 
covered  with  a  duplicature  of 
the  mantle  which  accompanies 
them  as  they  plunge  amid  the 
visceral  mass.  Without  leav- 
ing the  genus  Pholas,  the  cuil- 
lerons  may  be  seen  gradually 
contracting  in  their  breadths,  be- 
coming shorter,  and  approaching 
c  nearer  and  nearer  to  the  edge. 
But  if  other  shells  be  examined, 
which  obviously  form  the  links 
of  transition  from  the  Pholada  to 
the  Saxicava,  or  Petricola,  the 
processes  are  found  to  turn  upon  the  edge,  to 
become  coherent  with  it  so  as  to  form  a  salient 
margin,  and  by  their  free  extremity  to  produce 
a  projection  (/>,  fig.  364).  In  our  opinion  the 
toothings  of  the  hinge  of  all  the  other  bivalve 
shells  are  produced  in  the  same  manner;  but 
with  such  modifications  as  rarely  admit  of  those 
relations  being  traced  which  are  to  our  mind 
obvious  in  those  genera  that  have  just  been 
particularly  mentioned.  With  regard  to  the 
shells  of  the  genera  in  which  the  hinge  is 
complicated,  of  which  the  cardinal  edge  is 
thickened,  and  the  cavity  of  the  hook  partly 
filled  by  the  external  layer  of  the  shell,  it  is 
difficult  to  imagine  in  what  manner  the  suc- 
cessive growth  of  the  hinge  has  taken  place, 
and  to  make  out  its  analogy  in  point  of  struc- 
ture with  that  of  the  Petricola  pholadiformis 
and  of  the  Pholada  generally.  To  discover 
this  it  is  necessary  to  break  a  great  number  of 
the  shells,  or  to  make  various  sections  of  the 
edge,  vvhen  the  direction  of  the  denticulations 
with  which  it  is  furnished  must  be  followed. 
The  teeth  of  the  hinge  will  then  be  seen  arising 
from  the  summit  of  the  hook  (c,  Jig.  364), 
becoming  developed,  and  forming  a  solid  arc, 
surrounded  and  hidden  by  the  matter  of  the 
cardinal  edge  itself,  and  these  arcs  thus  disen- 
gaged will  be  found  to  present  the  strongest 
analogy  with  those  of  the  Pholada.  It  is  from 
viewing  the  hinge  in  this  manner  that  we  have 
been  induced  to  think  that  its  structure  was  in 
reality  of  sufficient  importance  to  make  it  be 
constantly  appealed  to  for  the  distinguishing 
characters  of  genera. 

Naturalists  have  agreed  to  designate  as  the 
cardinal  teeth  those  solid  projections  which 
arise  on  the  edge  of  the  hinge.  These  projec- 
tions on  the  one  valve  are  for  the  most  part 
accompanied  with  corresponding  depressions 


on  the  other  for  their  reception  mutually.  The 
depressions  are  called  cardinal  pits.  These 
cavities  and  these  projections  present  a  great 
variety  of  modifications  which  cannot  be  well 
understood  without  a  long  and  careful  study  of 
the  conchiferous  tribes  generally.  When  the 
teeth  are  collected  under  the  hook,  they  pre- 
serve the  title  of  cardinal  (b,  Jig.  365) ;  when 


Fig.  365. 


one  or  two  in  number,  and  remote  from  the 
centre  of  the  hinge,  they  are  named  lateral 
teeth.  Of  these  lateral  teeth  one  is  an- 
terior (c,  Jig.  365),  the  other  posterior  (dy 
fig.  365).  The  anterior  lateral  tooth  is  com- 
monly situated  at  the  extremity  of  the  lunule, 
and  the  posterior  lateral  tooth  at  the  extre- 
mity of  the  ligament.  The  cardinal  teeth, 
properly  so  called,  vary  in  number.  When 
there  are  but  two,  the  one  is  anterior,  the  other 
posterior ;  when  there  are  three  or  more,  those 
in  the  middle  are  entitled  median  teeth.  If 
the  hinge  be  composed  of  a  great  number  of 
teeth,  it  is  said  to  be  serial  (6,  6,  fig.  3£6). 


Fig.  366. 


Area. 


710 


CONCHIFERA. 


The  teeth  are  commonly  simple  and  conical ; 
occasionally  they  are  flattened  either  lengthwise 
or  transversely.  In  a  considerable  number  of 
species  they  are  grooved  to  different  depths  on 
their  summits,  and  the  teeth  are  then  said  to 
be  bifid  (e,  Jig.  365). 

There  are  other  parts  still  which  present 
themselves  upon  the  cardinal  edge,  and  of 
which  it  is  important  to  have  a  sufficient  know- 
ledge,— namely,  those  destined  for  the  implan- 
tation of  the  ligament  when  it  is  external ;  to 
these  parts  the  name  of  nympha  is  given. 
These  form  two  callosities  more  or  less  promi- 
nent, which  are  seen  along  the  posterior  and 
superior  edge  of  the  shell.  When  the  ligament 
is  internal,  it  rests  upon  a  cavity  generally  pro- 
minent towards  the  interior  of  the  valves,  and 
designated  by  the  name  of  cuilleron  or  spoon- 
shaped  cavity.  This  cuilleron  is  generally 
situated  in  the  centre  (c,  d,  Jig.  367)  of  the 

Fig.  367. 


hinge  ;  sometimes,  however,  it  becomes  a  little 
oblique,  elongated,  narrower,  and  runs  in  the 
direction  of  the  posterior  and  superior  edge. 

When  we  direct  our  attention  to  the  external 
forms  of  the  bivalve  shells,  we  observe  numerous 
modifications,  of  the  principal  of  which  it  is 
necessary  to  take  some  notice.  In  a  consi- 
derable number  of  species  the  two  valves  are 
alike,  when  the  shell  is  said  to  be  equivalved. 
When  one  of  the  valves  is  larger  than  the  other 
it  is  of  course  inequivalved ;  to  constitute  it  so 
it  is  not  necessary  that  the  shell  should  be 
irregular.  A  regular  shell  is  that  which  at 
liberty  always  presents  the  valves  alike  in  all 
the  individuals  of  the  species;  an  irregular 
shell  is  not  only  inequivalved,  but  farther,  the 


whole  of  the  individuals  of  the  same  species 
are  not  exactly  of  the  same  form,  and  want  the 
same  peculiarities  of  external  conformation 
generally.  The  Oysters  are  inequivalve  and  irre- 
gular shells ;  the  Corbules  are  inequivalve  and 
regular  shells ;  the  Venus  and  many  others  are 
perfectly  equivalved  and  regular  ;  the  Placunes, 
to  choose  a  particular  example,  are  in  like 
manner  equivalved  but  irregular.  The  length 
of  a  shell  is  always  calculated  from  the  summit 
of  the  hooks  to  the  inferior  edge.  All  that  are 
of  greater  length  than  breadth  are  entitled 
longitudinal,  (  Mytilus,  Pinna,  &c.  Jig.  353); 
and  all  that  are  of  greater  breadth  than  length 
are  named  transversal :  the  breadth  is  estimated 
by  a  line  passing  from  the  anterior  to  the 
posterior  extremity,  and  cutting  the  posterior 
axis  of  the  shell  at  a  right  angle,  (Solen,  Tel- 
Una,  &tc.  The  number  of  transverse  bivalve 
shells  is  very  great :  Jig.  367).  If  the  position 
of  the  hooks  with  relation  to  the  transverse 
and  longitudinal  lines  be  considered,  the  shell 
is  said  to  be  symmetrical,  when,  the  hooks 
being  in  opposition,  the  anterior  segment  is 
equal  to  the  posterior,  and  of  the  same  form 
in  consequence  of  this  symmetry ;  a  perfectly 
symmetrical  bivalve  shell  might  in  fact  be 
held  to  be  composed  of  four  similar  parts ;  but 
this  perfection  of  symmetry,  which  exists  in 
many  Brachiopods,  never  appears  among  the 
conchifera  properly  so  called,  even  those 
which  are  the  most  symmetrical  in  external 
character,  ascertain  Petuncula,  Jig.  358,  would 
be  more  correctly  designated  as  sub-symme- 
trical. When  the  hooks  are  inclined  to  one 
side  of  the  shell,  and  divide  it  into  two  equal 
parts,  it  is  said  to  be  equilateral.  But  if  the 
hook  be  carried  further  forwards  than  back- 
wards, so  that  one  of  the  sides  of  the  shell 
then  becomes  larger  than  the  other,  it  is  said  to 
be  inequilateral.  In  the  greater  number  of  the 
conchifera  the  two  valves  of  which  the  shell 
consists  join  each  other  accurately  around  their 
whole  circumference,  in  which  case  the  shell 
is  said  to  be  shut  or  closed.  When,  on  the 
contrary,  the  two  valves  present  a  vacancy 
between  them  in  some  part  of  their  circum- 
ference, when  they  are  approximated  as  nearly 
as  possible  to  one  another,  the  shell  is  said 
to  be  patulous.  This  open  space  is  vari- 
ously situated  in  different  species,  sometimes 
in  the  anterior  surface,  rarely  in  the  inferior 
edge,  but  pretty  frequently  in  the  posterior 
edge,  especially  in  those  species  of  the  class 
whose  mantle  is  prolonged  on  this  side  into 
one  or  two  syphons. 

Surfaces  of  the  valves. — Every  bivalve  shell 
has  two  surfaces,  an  external  surface  and  an 
internal  surface.  Various  parts  are  distin- 
guished on  the  external  surface, — the  hooks, 
the  belly,  the  edges,  the  lunule,  and  the 
corslet. 

External  surface.  1 .  The  hooks.  —  The 
protuberant  opposed  parts,  often  inclined  to- 
wards the  anterior  side,  and  presenting  an 
apex  of  various  degrees  of  sharpness  or  blunt- 
ness,  are  thus  denominated.  When  these 
hooks  are  very  much  inclined  forwards,  they 
are  styled  lateral.  If  they  are  particularly 


CONCHIFERA. 


711 


prominent,  they  are  said  to  be  cordiform. 
When  they  are  inclined  towards  one  another, 
so  that  their  summits  approximate,  they  are 
said  to  be  opposed.  The  hooks  in  no  case  in- 
cline to  the  posterior  side ;  but  occasionally 
they  disappear  almost  entirely,  and,  as  in  the 
Solens,  exhibit  no  kind  of  prominence.  In 
other  instances  again  they  project  a  great  way, 
and  form  the  most  prominent  part  of  the  shell 
(Mytilus,  Pinna),  in  which  case  the  hooks  are 
said  to  be  terminal. 

2.  The  belli/  of  the  shell  comprises  the 
greatest  part  of  the  exterior  surface.  It  is 
bounded  at  the  base  of  the  hook,  as  also  by 
the  lunule  and  the  corslet.  It  is  more  or  less 
rounded  or  flattened  according  to  the  general 
form  of  the  shell,  and  we  shall  speak  of  the  dif- 
ferent points  worthy  of  consideration  con- 
nected with  it  when  we  come  to  define  the 
various  particulars  of  the  external  surface  con- 
sidered in  a  general  manner. 

F/g.368  A. 


a,  superior  edge  ;  b,  uncus  ;  c,  Innula  ;  e,  anterior 
edge  ;  f,  inferior  edge  ;  g,  posterior  edge. 

Fig.  368  B. 


,  anterior  edge ;  b,  inferior  edge ;  c,  posterior 
edge ;  d,  edges  of  the  shield  ;  /,  ligament ; 
f  to  h,  nympha ;  h,  other  extremity  of  the  liga- 
ment ;  i,  point  of  the  uncus  or  hook  ;  /  to  n, 
Innula;  I,  anterior  cardinal  tooth;  j,  median 
cardinal  tooth  ;  g,  posterior  cardinal  tooth  ;  m, 
anterior  lateral  tooth  ;  o,  anterior  muscular  im- 
pression ;  p.  posterior  muscular  impression  ;  r, 
palleal  impression  ;  s,  sinuosity  of  the  palleal 
impression. 


3.  The  edges. — These  are  indicated,  pre- 
serving the  shell  in  the  position  which  we 
have  mentioned;  they  are  anterior,  posterior, 
inferior,  and  superior.  The  extent  of  these 
edges  is  very  various,  and  depends  entirely 
on  the  form  of  the  shell  and  the  position  of  its 
hooks.  Upon  this  particular  the  simple  in- 
spection of  a  collection  of  shells  will  give 
much  more  information  than  we  can  hope  to 
do  by  the  most  laboured  description ;  so  that 
we  shall  only  say  that  the  anterior  edge  cor- 
responds to  the  head  of  the  animal,  the  pos- 
terior to  its  posterior  extremity,  the  inferior  to 
its  ventral  aspect,  and  the  superior  to  its  back. 
The  edges  in  themselves,  however,  present  a 
few  particulars  which  it  were  well  to  mention. 
Sometimes  they  are  thin  and  cutting ;  very  com- 
monly too  they  are  thick  and  continue  simple. 
In  those  species  especially  whose  shells  are 
marked  externally  with  longitudinal  striae,  they 
are  notched  and  toothed  alternately,  the  pro- 
jections of  the  one  valve  in  almost  all  instances 
being  received  into  the  cavities  of  the  other. 
When  these  projections  and  notches  are  very 
fine,  the  shell  is  said  to  be  crenate;  if  larger, 
toothed;  when  very  large  and  few  in  number, 
with  their  summits  blunt,  again,  the  edge  is 
undulating  as  in  the  Tridacna;  on  the  con- 
trary it  is  angular  when  the  prominences  con- 
tinue sharp  as  they  do  in  certain  of  the  Ostreae; 
in  the  latter  case  the  edge  is  also  said  to  be 
widely  or  deeply  dentated. 

4.  The  lunula    does    not  occur  in  every 
genus  of  bivalve  shell.    It  is  met  with,  how- 
ever, among  the  greater  number  of  the  Mono- 
myaria ;  it  is  also  met  with  among  many  Dy- 
myaria,  and  is  particularly  conspicuous  in  the 
Venus.     It  is  a  space  comprised  on  the  ante- 
rior surface  immediately  under  the  hooks,  and 
is  generally  circumscribed  by  a  particular  line 
or  depression.    The  lunula  presents  certain  pe- 
culiarities which  it  is  often  of  consequence  to 
attend  to,  in   order  to  distinguish  certain  spe- 
cies otherwise  apt  to  be  confounded  with  one 
another.     Its  form  is  various,  sometimes  cordi- 
form, a  shape  which  almost  peculiarly  belongs 

to  inflated  and  subglobular  species;  sometimes 
lanceolate,  sometimes  very  narrow,  especially 
in  species  whose  shells  are  flattened.  The 
lunula  is  very  rarely  prominent,  unless  it  be 
towards  the  centre.  Sometimes  it  is  super- 
ficial, pretty  frequently  depressed,  and  there 
are  a  few  genera  or  species  in  which  it  is  deeply 
hollowed. 

5.  The  corslet  occupies  a  part  of  the  su- 
perior and  posterior  edge  of  the  shell.     It  is 
only  met  with  in  the  Dimyaria ;  it  is  not  so 
accurately  bounded  as  the  lunula ;  it  is  also 
wanting  in  a  great  number  of  genera,  in  which 
its  presumed  position  is  arbitrarily  determined. 
It  is  towards  its  upper  part  that  the  nymphae 
are  observed  in  those  species  whose  ligament 
is  external. 

In  a  very  considerable  number  of  Mono- 
myarians  the  lunula  and  corslet  are  replaced 
by  certain  projecting  parts  to  which  the  name 
of  auricula  or  auricles  has  been  given.  These 
occur  more  especially  in  the  Pecten  family — 
the  Pectinites  of  Lamarck ;  they  are  distin- 


712 


CONCHIFERA. 


guished  into  anterior  and  posterior,  and  they 
are  frequently  unequal. 

If  we  now  turn  to  the  particulars  of  the 
external  surface  of  the  shell  of  the  conch  i- 
fera,  we  shall  find  many  points  worthy  of 
being  attentively  noted.  In  a  very  great 
number  this  surface  is  covered  with  a  thin 
and  frequently  deciduous  lamina  of  a  sub- 
corneous  and  often  filamentous  substance,  to 
which  the  title  of  epidermis  has  been  given. 
This  matter  is  secreted  by  the  most  external 
edge  of  the  mantle,  but  observers  have  not 
yet  stated  in  what  manner  the  secretion  takes 
place,  and  what  means  the  creature  employs 
to  make  this  epidermis  adhere  so  strongly  to 
its  shell.  The  epidermis  often  occurs  both  of 
considerable  thickness  and  extent  (Glycimeris, 
Solemya),  and  thus  constitutes  an  important 
portion  of  the  shell.  In  other  genera  the  epi- 
dermis appears  to  be  wanting  entirely,  and  in 
others  bears  some  resemblance  to  velvet  of 
thicker  or  thinner  pile,  and  then  consists  of  a 
large  quantity  of  short  hair,  standing  erect, 
and  more  or  less  closely  set.  In  some  species 
these  hairs  become  more  scanty,  but  increase 
greatly  in  length,  as  we  perceive  in  certain 
Archidae  and  Bucarides.  When  it  occurs  in 
certain  species  the  successive  growths  of  which 
are  manifested  by  irregular  ridges,  the  epider- 
mis is  irregularly  squamous.  The  epidermis 
is  insufficient  to  furnish  any  generic  character 
that  can  be  depended  on ;  for  there  are  certain 
extremely  natural  genera  in  which  some  species 
are  covered  with  it  whilst  others  are  entirely 
naked. 

The  other  particulars  of  the  external  surface 
of  the  shell  are  soon  glanced  at :  they  consist 
of  stria,  ridges  or  ribs,  and  furrows,  which, 
according  to  their  direction,  are  distinguished 
into  longitudinal  when  from  the  hook  they  run 
towards  the  inferior  margin,  and  transverse 
when  they  foliow  an  opposite  course,  that  is  to 
say,  when  they  run  from  before  backwards ; 
they  are  oblique,  again,  when  they  follow  a  line 
in  any  way  inclined  to  the  longitudinal  or  the 
transverse.  These  stria,  ridges,  and  furrows, 
may  cross  one  another,  and  the  shell  is  then 
trellised.  They  may  also  severally  present  a 
great  variety  of  particular  appearances,  the  de- 
finitions of  which  may  be  found  in  the  ordinary 
elementary  works  on  Conchology ,  but  which  may 
all  be  learned  much  more  rapidly  from  even  a 
very  moderately  attentive  study  of  the  shells 
themselves  than  from  any  written  description, 
however  minute  and  accurate. 

Internal  surface. — The  inner  surface  of  bi- 
valve shells  is  commonly  smooth  and  polished, 
and  often  presents  different  colours  which  de~ 
pend  on  the  secretion  of  that  part  of  the  man- 
t'e  which  produces  the  solid  laminse  of  the 
inner  surface.  The  greater  number  of  shells 
affe  white  within,  and  many  of  them  are  na- 
creous or  like  mother-of-pearl.  Mother-of- 
pearl  would  appear  to  be  the  consequence 
of  a  molecular  arrangement  of  the  calcareous 
matter  intimately  united  in  a  constant  ratio 
with  the  animal  matter  by  the  combination 
of  which  the  shell  is  formed.  The  pro- 
portion of  the  two  substances  does  not  ap- 


pear to  be  the  same  in  the  non-nacreous  and 
the  nacreous  shells ;  there  are  some  which 
afford  a  much  larger  proportion  of  calcareous, 
and  others  which  yield  a  much  larger  propor- 
tion of  animal  matter  when  analysed  than  is 
usual.  Naturalists  are  now  generally  aware 
of  the  experiments,  an  account  of  which  is  to 
be  found  in  the  Philosophical  Transactions, 
from  which  it  appears  that  the  nacreous  lustre 
is  owing  to  the  decomposition  of  light  by  an 
infinity  of  asperities  of  excessive  minuteness 
which  beset  the  surface  of  the  shell.  It  has, 
indeed,  been  found  possible  by  means  of  an 
impression  from  a  mother-of-pearl  surface  taken 
in  sealing-wax  especially,  to  transfer  the  power 
of  exhibiting  corresponding  phenomena  to  the 
surface  of  the  wax.* 

There  is  a  variety  of  characters  exhibited 
by  the  interior  of  the  valves  which  it  is  of  con- 
sequence to  be  familiar  with.  In  shells  which 
have  belonged  to  dimyary  mollusks,  two 
muscular  impressions  of  variable  depth  are 
constantly  to  be  found  in  the  interior.  Some- 
times they  are  so  superficial  that  they  escape 
an  examination  which  might  even  be  charac- 
terized as  minute.  One  of  these  impressions 
is  on  the  anterior  side  of  the  shell,  the  other 
on  the  posterior.  They  are  generally  sub- 
rotund  ;  sometimes,  however,  they  are  elon- 
gated, which  serves  as  an  announcement  that 
the  muscles  were  flattened.  In  some  genera 
these  muscular  impressions  are  of  a  particular 
form,  as  may  be  observed  in  the  Lucina  for 
example.  It  is  a  circumstance  worthy  of  ob- 
servation that  the  muscles  of  the  animal  shift 
their  place  and  come  forward  in  the  shell  in 
proportion  as  it  grows,  and  it  might  have  been 
concluded,  a  priori,  that  this  could  not  be 
otherwise,  when  the  mode  of  increment  pecu- 
liar to  the  class  is  taken  into  consideration. 
On  escaping  from  the  ovum,  a  conchiferous 
mollusk  is  already  provided  with  its  shell,  of 
course  of  very  small  size,  and  its  two  adductor 
muscles ;  and  the  relations  of  these  muscles  to 
the  shell  and  the  other  internal  organs  are  the 
same  as  at  every  subsequent  period.  When 
the  animal  has  attained  to  some  lines  in  length, 
and  by  the  lapse  of  time  to  much  larger  di- 
mensions, did  not  the  muscles  undergo  a 
gradual  displacement  the  shell  would  be  found 
as  thin  at  the  summit  as  it  was  on  escaping 
from  the  egg,  and  the  muscles  prolonged  into 
the  interior  of  the  hook.  Now,  not  only  does 
the  shell  go  on  increasing  in  thickness  and  the 
hooks  fill  up,  but  observation  shows  that  the 
adductor  muscles  always  preserve  the  same 
relations  and  the  same  proportions.  To  study 
in  the  best  possible  manner  the  successive  dis- 
placements of  the  muscular  impressions,  the 
best  mode  is  to  saw  a  fossil  oyster-shell  length- 
wise in  a  line  passing  from  the  summit  through 
the  centre  of  the  muscular  impression.  The 
impression  will  then  be  seen  beginning  towards 

*  [We  have  heard  this  point  disputed.  The 
power  which  the  sealing-wax  had  certainly  gained 
in  some  instances  of  exhibiting  the  mother-of- 
pearl  lustre  was  afterwards  shown  to  depend  ori  the 
wax  having  detached  a  minute  film  from  the  stir« 
face  upon  which  it  had  been  pressed. — ED.] 


CONCiriFEllA. 


713 


the  summit  and  increasing  gradually  in  its 
dimensions,  so  as  to  form  a  long  triangular 
imprint,  running  obliquely  through  the  thick- 
ness of  the  shell.  When,  at  a  very  early  age, 
the  shell  was  extremely  thin,  the  muscular  im- 
pression existed  very  near  to  the  external  sur- 
face; but  in  proportion  as  the  animal  has 
become  older,  and  new  layers  of  calcareous 
matter  have  been  successively  added  to  the 
former,  the  muscular  impression  is  found  to 
have  become  farther  and  farther  removed  from 
the  external  surface.  It  is  generally  on  the 
surface  of  the  muscular  impressions,  and  in 
the  substance  of  the  adductor  muscles  them- 
selves, that  those  peculiar  solid  arid  highly 
prized  excrescences  called  pearls  are  produced. 
These  excrescences  are  engendered  in  a  very 
considerable  number  of  genera,  and  it  is  to  be 
presumed  that  they  may  occasionally  exist  in 
all ;  it  is,  however,  among  the  Monomyaria 
that  pearls  are  most  constantly  formed. 

Various  causes  have  been  assigned  to  explain 
the  formation  of  pearls.  But  it  seems  enough 
to  be  aware  in  u  general  way  of  the  manner  in 
which  bivalve  shells  grow  to  understand  how 
pearls  are  produced.  Their  production,  it  would 
appear,  may  be  assigned  to  some  accident  hap- 
pening to  the  animal ;  sometimes  a  few  grains 
of  sand  getting  between  the  mantle  and  the 
shell  prove  nuclei  for  their  formation,  but  still 
more  frequently  they  are  consequences  of  per- 
forations made  by  a  species  ofAnnelidan,  to 
the  attacks  of  which  bivalve-shelled  animals 
are  obnoxious.  In  either  case  the  animal,  feel- 
ing itself  injured,  deposits  over  the  grain  of 
sand  or  the  small  orifice  made  by  the  Annel- 
idan,  a  thin  layer  of  nacreous  matter,  secreted 
accidentally  and  superabundantly  with  re- 
ference to  its  regular  laminae  of  progressive 
growth.  In  consequence  of  this,  the  shell  at 
the  point  where  the  grain  of  sand  lodges  or 
where  it  is  wounded  acquires  more  than  its 
usual  thickness.  This  thickening,  from  the 
mere  fact  of  its  presence,  becomes  a  perma- 
nent cause  of  excitement  to  the  mantle  of  the 
animal,  so  that  this  organ  goes  on  secreting  an 
unusual  quantity  of  calcareous  matter,  in  con- 
sequence of  which  there  results  an  elevation 
that  increases  with  the  age  of  the  animal,  so 
much  the  more  rapidly  as  the  annoyance  has 
been  greater  and  more  permanent.  When  the 
mass  has  increased  so  much  as  to  penetrate 
somewhat  deeply  into  the  substance  of  the 
organs,  it  is  then  apt  to  go  on  increasing  by 
depositions  of  nacreous  matter  upon  one  of  its 
extremities,  by  which  we  have  pedunculated 
and  elongated  pearls  produced.  Zoologists 
have  also  asked  how  those  pearls  that  are 
found  perfectly  free  in  the  interior  of  conchi- 
ferous  mollusks  were  formed.  We  shall  first 
observe  that  these  pearls  arc  met  with  more 
especially  in  the  substance  of  the  adductor 
muscles ;  now  if  it  be  remembered  that  these 
muscles  shift  their  place  in  proportion  as  the 
animal  grows,  it  may  readily  enough  be  al- 
lowed that  a  pediculated  pearl  developed  on 
the  surface  of  the  muscular  impression  itself, 
might  be  detached  from  its  connexion  with 
the  shell  by  the  advance  of  the  muscle,  be- 

VOL.  I. 


come  free  in  the  substance  of  this  muscle,  and 
there  continue  to  increase  \vith  more  or  less 
rapidity.  This  explanation,  which  we  advance 
for  the  first  time,  appears  to  us  sufficiently 
plausible ;  but,  before  admitting  it  as  an  esta- 
blished fact,  it  would  be  well  to  institute 
some  experiments  in  regard  to  the  successive 
changes  of  position  undergone  by  the  addm  t..> 
muscles  of  a  conchiferous  animal. 

Fig.  369. 


The  mantle,  as  we  have  seen,  is  attached  to 
the  shell  by  a  determinate  portion  of  its  sur- 
face. In  the  Dimyaria  the  part  that  is  ad- 
herent is  not  far  from  the  thickened  edge  of  the 
mantle  ;  it  adheres  by  means  of  the  small 
muscles  which  regulate  its  contractions,  as  well 
as  those  of  the  tentaculary  papillae  with  which 
it  is  commonly  fringed.  In  the  Monomyaria 
the  adhesion  of  the  mantle  is  situated  much 
higher,  and  very  nearly  at  the  place  where  the 
lobes  of  the  mantle  are  detached  from  the 
general  mass  of  the  body.  From  the  adhe- 
sion of  the  mantle  to  the  shell  there  results  a 
linear  impression,  to  which  M.  de  Blainville 
has  given  the  name  of  pa >.l 'leal  impression ;  in 
the  Dimyaria  it  extends  from  before  backwards, 
from  the  anterior  to  the  posterior  adductor 
muscular  impression,  following  the  circum- 
ference of  the  edge.  This  linear  impression 
is  simple  when  it  presents  no  inflexion  in  its 
course.  In  a  considerable  number  of  the  Di- 
myaria it  is  observed  to  form  a  notch  of  dif- 
ferent depths  in  different  species,  directed 
towards  the  mantle.  This  notch  appears  to  be 

3  A 


714 


CONCHIFERA. 


produced,  as  we  have  already  said,  by  the  pro- 
per retractor  muscle  of  the  siphons. 

Besides  the  muscular  impressions  of  which 
we  have  now  spoken,  several  others  of  much 
less  importance  have  been  particularized  in  the 
greater  number  of  the  conchiferous  mollusks. 
All  the  species  that  have  a  foot  have  peculiar 
muscles  to  move  this  organ,  and  these  have 
their  fixed  point  of  action  on  some  point  of 
the  interior  of  the  shell.  They  are  generally 
divided  into  two  principal  fasciculi ;  the  one 
runs  to  be  inserted  within  the  hooks,  the  other 
in  the  Dimyaria  proceeds  to  be  attached  before 
and  above  the  posterior  adductor  muscular 
impression.  In  the  Monomyaria,  the  foot  of 
which  is  generally  rudimentary  and  without 
use,  we  observe  nothing  more  on  each  side 
of  the  body  than  a  single  small  fibrous  fas- 
ciculus, the  impression  of  which  is  found  on 
the  inside  of  the  hooks.  In  some  genera  of 
Dimyaria,  and  particularly  in  the  Unio,  we 
observe  three  and  sometimes  four  muscular  im- 
pressions belonging  obviously  to  the  adductor 
muscles  of  the  valves,  which  are  occasioned 
by  the  anterior  adductor  muscle  in  particular 
being  divided  into  two  fasciculi,  often  of  un- 
equal size,  as  in  certain  Uniones,  and  some- 
times equal  and  of  considerable  magnitude,  as 
among  the  Iridines. 

From  the  summary  and  concise  view  we 
have  taken  of  the  principal  facts  in  the  organi- 
zation of  the  Conchifera,  very  important  con- 
clusions may  be  drawn  with  reference  to  the 
classification  of  these  animals. 

Taking  the  Conchifera,  properly  so  called, 
and  looking  narrowly  into  that  which  is  of 
most  importance  in  their  organization — the  ner- 
vous system,  we  find  two  principal  modifica- 
tions, coinciding  in  a  very  remarkable  manner 
with  the  number  of  the  muscles.  This  num- 
ber of  the  muscles,  permanently  proclaimed 
by  the  impressions  they  leave  on  the  shell, 
presents  an  important  character  by  means  of 
which,  while  we  define  their  limits  somewhat 
more  strictly,  we  feel  authorized  in  retaining  the 
two  grand  orders  of  Lamarck, —  the  Conchi- 
fera Dimyaria,  and  the  Conchifera  Mono- 
myaria. A  fact  of  some  importance,  and 
brought  to  light  by  the  observations  of  Poli, 
is  that  a  small  nervous  ganglion  exists  at  the 
point  of  commissure  in  those  acephalous  mol- 
lusks which  have  the  lobes  of  the  mantle  con- 
joined. This  peculiarity  gives  new  conse- 
quence to  the  characters  drawn  from  the  con- 
joined or  disunited  state  of  the  lobes  of  the 
mantle.  Unfortunately  the  circumstance  is 
not  always  indicated  upon  the  shell ;  it  is,  in 
fact,  only  obvious  upon  those  inhabited  by 
siphoniferous  animals;  it  is  quite  inapprecia- 
ble upon  those  the  inhabitants  of  which  have 
siphons  so  short  as  not  to  require  a  particular 
retractor  muscle  to  draw  them  within  cover  of 
the  shell.  With  regard  to  the  other  organic 
characters  which  furnish  data  available  in  clas- 
sifying the  Conchiferous  mollusks,  these  are  all 
of  so  little  permanency  that  they  are  only 
useful  in  supplying  secondary  hints  for  the 
arrangement  of  families  and  genera.  Thus 
neither  the  branchiae  nor  the  heart  present  any 
character  susceptible  of  generalization  or  of 


contrast.  Better  data  might  perhaps  be  ob- 
tained from  the  conformation  of  the  organs  of 
digestion  ;  but  these  organs  have  hitherto  been 
examined  in  comparatively  so  small  a  number 
of  genera  and  species  that  they  cannot  be 
brought  forward  usefully  in  supplying  cha- 
racters for  a  general  classification.  If,  as  we 
ourselves  feel  inclined  to  do,  the  hinge  be 
taken  as  the  point  of  starting  in  the  Pholades, 
this  part  may  be  made  the  means  of  giving 
excellent  characters  in  its  principal  modifica- 
tions for  the  establishment  of  genera.  It  is, 
indeed,  very  remarkable  that  we  should  find 
the  characters  as  indicated  by  the  hinge 
almost  constantly  in  harmony  with  those  af- 
forded by  the  rest  of  the  organization;  and 
with  a  few  exceptions,  relative  to  several  ex- 
tremely natural  families,  that  of  the  Unios  for 
example,  all  that  is  valuable  in  the  generic  cha- 
racters generally  may  be  preserved  along  with 
the  characters  supplied  by  the  hinge.  Ano- 
ther character  which  may  be  usefully  employed 
in  classification  is  assumed  from  the  regularity 
or  irregularity  of  the  shell  of  the  animal ;  in 
generalizing  upon  this,  like  groups  are  obtained 
in  the  two  principal  divisions  of  the  Conchifera, 
and  the  two  principal  divisions  of  the  classi- 
fication are  referred  to  the  simplicity  or  exact- 
ness of  the  dichotomy,  whilst  natural  groups 
are  preserved  as  much  as  may  be  in  the  linear 
arrangement. 

Method,  it  must  ever  be  remembered,  is  an 
artificial  means  of  introducing  order  among  a 
series  of  observed  facts,  and  of  approximating, 
according  to  the  analogy  of  their  organization, 
the  beings  which  nature  has  scattered  over  the 
face  of  the  earth ;  method  is  a  human  creation 
altogether,  and  in  this  light  must  it  be  viewed. 
To  be  all  it  ought,  eveiy  known  fact  must  be 
included,  and  the  greatest  possible  amount  of 
organic  relationships  between  the  individuals 
of  each  great  class  must  be  indicated.  In  an 
exposition  of  facts  seriatim,  and  as  they  occur 
in  a  book,  every  thing  has  to  be  arranged  in 
sequence,  and  therefore  in  the  linear  mode, 
now  so  generally  followed  by  naturalists.  In 
this  way,  however,  it  is  impossible  to  express 
the  enchainment,  the  inosculation,  so  to  speak, 
of  the  different  groups.  To  counterbalance  this 
inconvenience,  we  are  of  opinion  that  the  clas- 
sification ought  to  be  made  with  lateral  offsets, 
now  terminating  abruptly,  now  divided  once  or 
twice,  sometimes  inosculating  variously,  and 
again,  departing  from  a  common  trunk,  dispo- 
sed in  one  case  in  a  right  line,  in  another  in  a 
curved  line,  and  in  a  third  in  a  circle.  We 
conceive  that  it  is  according  to  these  new  views 
only  that  the  acephalous  mollusks  can  be  pro- 
perly arranged ;  it  is  accordingly  upon  the 
principles  just  announced  that  the  following 
table  is  constructed. 

Although  in  the  present  state  of  our  know- 
ledge of  these  animals  many  important  parti- 
culars are  still  unquestionably  wanting,  this 
division  of  the  molluscous  tribes  nevertheless 
presents  fewer  gaps  than  any  of  the  others,  in- 
asmuch as  opportunities  have  occurred  of  ex- 
amining some  one  or  other  of  the  animals  be- 
longing to  the  whole  of  the  genera. 


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CONTRACTILITY. 


This  tabular  view  of  the  classification  exhibits 
certain  particulars,  upon  which  we  deem  it 
necessary  to  offer  a  few  explanatory  remarks. 
As  we  said  before,  the  series  as  a  whole  may 
be  regarded  as  a  common  trunk,  from  which 
various  branches  spring,  sometimes  anastomo- 
sing, sometimes  ending  abruptly.  It  is  thus 
that  from  the  Clavigella  we  observe  a  lateral  line 
departing,  formed  of  the  genera  Fisttdana, 
Gulcomma,  and  those  of  Lamarck's  family 
of  Petricola.  These  genera  descend  parallel  to 
the  common  trunk  of  the  classification,  so  as 
to  approximate  in  as  great  a  degree  as  possible 
the  genus  Venerupls  to  the  genus  Venus.  The 
genus  Pandora  has  numerous  analogies  on  one 
side  with  the  Corbula,  l*ut  it  lias  also  many 
with  the  members  of  the  genus  Osteodesma,  on 
which  account  it  is  made  to  depart  laterally 
from  the  Corbula,  and  to  ascend  towards  the 
Osteodesmata.  The  Luiraria  are  also  variously 
related  to  several  genera  of  the  Osteodesmala, 
and  this  genus  is  joined  to  that  of  the  Thracia 
by  means  of  the  genus  Anatinella,  which  we 
place  crosswise  to  connect  the  genera  just  men- 
tioned. In  the  Mactracea,  we  pass  without 
any  very  great  stride  from  the  Luiraria  to  the 
Mactra,  from  the  Mactra  to  the  Erycina 
and  to  the  Amphidesma.  Farther,  in  order 
not  to  interrupt  this  series  of  relation- 
ships, we  place  upon  a  lateral  line  departing 
from  the  Mactra  the  two  genera  Mcsodcsma 
and  Crassatella.  Every  naturalist  knows  how 
great  the  resemblance  is  between  the  flat  and 
broad  Solens  (  Soletcllina,  De  Blainv.)  and  the 
Psummobice ;  but  we  also  know  that  the  genus 
Psammubia  has  so  many  analogies  with  the 
family  of  the  Tellinida,  that  it  is  impossible  to 
detach  it  from  this  family  in  order  to  include  it 
within  the  family  of  the  Solenaceae.  To  avoid 
interrupting  the  relations  of  this  genus  to  those 
of  the  Solcn  family,  we  have  recourse  to  an 
ascending  line  composed  of  the  genera  Solen- 
ertus,  Panopaa,  Sulen,  Solemya,  and  Glyci- 
meris,  by  which  means  we  approximate,  as 
much  as  possible,  these  last  genera  to  the  fa- 
milies Pholadia  and  Osteodesrnata,  with  which 
they  have  in  fact  unequivocal  relationships  in 
point  of  organization.  We  consider  the  family 
of  the  Lucinidae  as  a  lateral  and  truncated 
branch  of  the  Conclude,  divaricating  from  the 
genus  Astarte.  With  regard  to  the  Cycladn,  we 
place  the  genus  Glaucoma  of  Mr.  Cray  laterally, 
between  the  Cyrcnas  and  the  Vcnuses,  so  as  to 
establish  the  connexion  between  the  two  ge- 
nera; whilst  departing  also  from  the  genus 
Cyrena  we  place  our  genus  Cyrenclla  obliquely 
in  order  to  make  it  join  that  of  Lucina, 
this  genus  of  Cyrenella  being  to  Cyrena 
and  Lucina  that  precisely  which  the  genus 
Glaucoma  is  to  Cyrena  and  Venus.  To 
us  the  family  of  the  Chamacea  is  a  lateral 
offset  from  that  of  the  Cardiaceu,  and  although 
the  Elheria  and  the  family  of  the  lludisies  are 
in  reality  among  the  number  of  those  Conchife- 
rous  mollusca  which  have  the  lobes  of  the 
mantle  disjoined,  still  as  they  do  not  imme- 
diately arrange  themselves  in  any  particular 
part  of  this  section,  we  have  placed  them  to  the 
side  in  continuation  of  the  family  of  the  Cha- 


macea, but  underneath  them.  The  family  of 
the  Ostracea  we  now  believe  to  consist  of  the 
single  genus  Ostrea,  and  we  propose  under  the 
name  of  Placunida  a  family  containing  the 
three  genera  P lacuna,  Placunonomia,  and  Ano- 
mia,  which  according  to  our  views  constitute  a 
descending  and  lateral  line  really  intermediate 
to  the  Conchifera  and  the  Brachiopoda. 

BIBLIOGRAPHY. —The  following  works  and 
essays  may  be  referred  to  as  still  interesting 
on  the  natural  history  of  the  Conchifera.  Reau- 
mur, De  la  formation  et  de  Faccroissement 
des  coquilles,  Acad.  de  Paris,  An  1709  et  An 
1716;  Ej.  De  la  maniere  dont  plusieurs  especes 
d'animaux  de  mer  s'attachent  au  sable,  aux  pierres, 
&c.  ibid,  An  1711.  Wulch,  Vom  Wachsthum  und 
den  Farben  der  Konchilienschaalen.  Besch.  der 
Berlin.  Naturforsch.  Gesell.  B.  i.  S.  230.  Miiller, 
Anmerk.  ueber  Walch,  ibid,  B.  ii.  S.  116.  *  * 
Cuvier,  Nouvelles  Rech.  sur  les  coquilles  bivalves, 
Societe  Philomath.  A.  7,  p.  83.  Lister,  Anatomy 
of  the  Scallop,  Philos.  Trans.  Year  1697.  Ant. 
van  der  Heide,  Anatome  Mytuli,  12mo.  Amst. 
1684.  Bojanus,  Sendschreiben  an  G.  Cuvier 
iiber  d.  Athmen  und  Kreislaufswerkzeuge  d.  Zwei- 
shaaligen  Muscheln,  4to.  Jena,  1820".  Mangili, 
Ricerche  nuovi  zootomiche  sopra  alcune  specie  di 
Conchiglie  Bivalvi,  8vo.  Milano,  1804.  Brack, 
De  ovis  ostreorum,  Misc.  Ac.  Nat.  cur.  Dec.  2, 
An  8.  Koehlreuter,  Obs.  anat.  physiol.  Mytili 
cygnei  (Lin.)  concernentes,  Nov.  Act.  Petrop. 

(G.  P.  Des  Hayes.) 

CONTRACTILITY.  — Since  it  has  been 
generally  understood,  that  all  the  most  striking 
and  conspicuous  movements  which  take  place 
in  living  animals,  depend  on  peculiar  contrac- 
tions of  certain  of  their  solids,  the  circum- 
stances of  these  contractions,  the  causes  by 
which  they  are  excited,  and  the  laws  by  which 
they  are  regulated,  have  been  justly  regarded 
as  objects  of  the  highest  interest,  and  of  fun- 
damental importance,  in  physiology.  The 
term  Irritability  was  employed  by  Haller  and 
his  followers,  to  denote  all  such  contractions 
in  living  bodies,  as  they  judged  to  be  peculiar 
to  the  living  state  ;  but  more  recent  inquiries 
have  shewn  the  necessity  of  distinguishing 
different  species  of  these  contractions ;  and  the 
more  comprehensive  term  Contractility  is  now 
pretty  generally  employed.  To  this  the  epithet 
Vital,  in  physiological  discussions,  may  usually 
be  understood  as  prefixed. 

It  is  to  be  remembered,  however,  that  several 
of  the  animal  textures  are  endowed  with  a  pro 
petty  of  contraction,  in  certain  circumstances, 
which  is  not  peculiar  to  their  living  state,  but 
subsists  as  long  as  their  structure  remains  unal- 
tered after  death ;  and  the  distinction  between 
the  phenomena  resulting  from  this  cause,  and 
those  which  are  strictly  vital,  has  not  always 
been  accurately  observed.  Thus  many  of  the 
soft  animal  textures,  muscles  to  a  certain  de- 
gree, tendons  and  ligaments  in  a  greater  degree, 
and  arteries  in  a  still  greater  degree,  are  elastic, 
and  liable  to  contractions  from  that  cause  when 
stretched.  The  Contractility  de  Tissu  of  Bichat 
is  in  most  cases  to  be  considered  simply  as 
Elasticity,  although  in  some  cases  (as  when  he 
assigns  this  property  as  the  reason  of  the  re- 
traction of  the  cut  extremities  of  a  living  muscle 


CONTRACTILITY. 


717 


or  of  the  stiffening  of  limbs  after  death,)  he 
gives  this  name  to  contractions  which  are 
strictly  vital.  Almost  all  animal  substances 
are  liable  to  contraction  from  heat,  and  from 
the  application  of  various  chemical  agents 
which  affect  them  as  astringents,  to  which 
property  Bichat  gave  the  name  of  Contractilitc 
par  me ornisscmcnt ;  and  it  is  easy  to  perceive 
that  this  property  also,  although  persistent  in 
the  perfectly  dead  body,  and  therefore  inde- 
pendent of  life,  may  give  occasion  to  contrac- 
tions which  may  sometimes  be  mistaken  for 
indications  of  the  strictly  vital  contractility. 

Confining  our  attention,  however,  to  such 
contractions  of  the  solids  of  organized  bodies, 
as  are  exhibited  by  them  only  in  their  living 
state,  i.e.  so  long  as  they  present  that  assem- 
blage of  phenomena,  to  which  we  give  the 
name  of  Life, — we  proceed  to  state  the  facts 
which  seem  to  be  most  important  and  best 
ascertained,  first,  as  to  the  modes  in  which 
they  are  excited ;  secondly,  as  to  their  pheno- 
mena, and  varieties ;  tiurdly,  as  to  the  condi- 
tions necessary  to  their  manifestation;  and, 
lastly,  as  to  the  laws  which  regulate  them. 

I.  It  is  universally  known,  that  the  most 
striking  examples  of  vital  contractions  are  seen 
in  the  effects  produced  by  various  stimuli 
acting  on  muscles,  particularly  those  of  volun- 
tary motion,  and  the  heart.  The  essential  cha- 
racters of  muscular  fibres,  their  composition 
nearly  akin  to  the  fibrin  of  the  blood,  their 
arranuemei't  in  parallel  fasciculi,  which  are 
bound  together  by  cellular  membrane,  their 
soft  texture,  arid  slight  elasticity  are  also  ge- 
nerally known.  The  change  excited  by  sti- 
muli acting  on  them  is  a  contraction  in  the 
direction  of  the  visible  fibres  of  the  muscle, 
which  in  the  healthy  state  always  rapidly 
alternates  with  relaxation;  and  by  these  two 
circumstances, —  the  excitation  by  stimulus, 
and  the  quickly  ensuing  relaxation, — we  dis- 
tinguish that  form  of  Vital  Contractility,  to 
which  the  term  Irritability  is  most  correctly 
applied. 

The  stimuli  which  produce  this  effect  are 
very  various;  and  the  experience  of  our  own 
bodies  points  out  the  obvious  distinction  of 
these  into  physical  and  mental.  Of  the  first 
kind,  air  and  water,  especially  if  aided  by  heat, 
act  decidedly  in  this  way;  but  those  which 
have  been  chiefly  used  in  experiments  are,  dis- 
tension, especially  in  the  case  of  the  hollow 
muscles,  such  as  the  heart  or  bladder, — che- 
mical acrids,  such  as  acids,  alkalies,  various 
alkaline,  earthy,  or  metallic  salts, — and  elec- 
tricity or  galvanism.  The  effect  of  all  these 
stimuli  is  much  increased  by  their  being  sud- 
denly applied. 

It  has  also  been  long  known,  that  many 
muscles  are  excited  to  contraction  by  such  sti- 
muli, when  applied  to  certain  nerves,  entering 
their  substance,  or  to  certain  parts  of  the  spinal 
cord  or  brain,  even  more  effectually  than  by 
applications  to  themselves;  and  likewise,  that 
it  is  only  when  those  nerves  are  entire,  up  to 
the  brain,  that  those  muscles  which  are  natu- 
rally obedient  to  the  mental  stimulus  of  the 
Will,  can  be  excited  by  voluntary  efforts. 


From  these  different  modes  of  excitation  of 
the  contractile  power  of  muscular  parts,  diffe- 
rent names  have  been  given  to  the  power 
itself,  as  by  Ilaller,  who  applied  the  term 
/'/.v  Tunica  to  the  contraction  from  distension, 
Vis  Insita  to  the  contraction  from  irritation  of 
the  muscular  fibres  themselves,  Vis  Ncrvosa  to 
the  contraction  from  irritation  of  a  nerve,  and 
Vis  Animalis  to  the  contraction  from  volition, 
acting  at  the  brain  and  transmitted  through  a 
nerve;  or  again  by  Hichat,  who  applied  the 
term  Conlractilitc  Or«ani</nc  Sensible  to  the 
contractions  excited  by  any  kind  of  irritation, 
acting  on  muscular  fibres  themselves,  and  the 
term  Contractilitc  Animate  to  those  excited  by 
stimuli,  whether  mental  or  physical,  acting  on 
the  nerves,  spinal  cord,  or  brain.  Hut  it  is 
obviously  more  correct  to  distinguish  the  dif- 
ferent varieties  of  the  vital  power  according  to 
the  phenomena,  which  the  contracting  part 
presents,  than  according  to  the  manner  in 
which  the  contractions  are  excited ;  and  there- 
fore those  terms  have  fallen  much  into  disuse. 
In  most  instances,  it  is  the  same  vital  power  of 
Irritability,  as  above  defined,  which  is  called 
into  action  in  these  different  ways. 

It  is  only  of  late  years,  that  it  has  been 
fully  ascertained,  as  to  the  excitement  of  vital 
contractions  through  nerves :  1,  that  it  is,  almost 
exclusively,  in  the  case  of  muscles  which  are 
naturally  subject  to  the  Will,  that  even  physical 
irritation,  confined  to  the  nerves,  has  power 
to  excite  contraction;  and  2,  that  these  muscles 
have  nerves,  or  nervous  filaments,  from  two 
distinct  sources,  viz.  from  the  anterior  and 
posterior  columns  of  the  spinal  cord,  and  their 
prolongations  within  the  cranium;  and  that 
it  is  by  irritation  of  the  first  of  these  only, 
(or  almost  exclusively,)  that  the  muscular  con- 
tractions are  excited.*  From  these  facts,  it 
appears  obvious,  that  the  grand  and  eternal 
law  of  separation,  as  Ilaller  calls  it,  of  the  Vo- 
luntary and  Involuntary  muscles,  consists  essen- 
tially, not  in  different  powers  of  the  muscular 
parts,  but  in  different  endowments  of  the  ner- 
vous filaments  which  enter  them. 

In  regard  to  the  excitation  of  muscular  con- 
traction through  nerves,  it  is  also  to  be  ob- 
served, that  although  the  action  of  muscles  in 
obedience  to  the  will  is  the  most  obvious  and 
striking  example,  in  the  living  body,  where 
the  intervention  of  a  change  in  a  nerve  is  known 
to  be  an  essential  condition  of  the  act,  yet 
there  are  many  examples  of  movements,  per- 
formed by  voluntary  muscles,  in  obedience  to 
mental  stimuli,  but  not  to  volitions,— to  sensa- 
tions, or  other  involuntary  acts  of  mind,  even 
in  opposition  to  efforts  of  the  will.  These  con- 
stitute a  very  important  class  of  vital  motions, 
and  are  known  to  be  equally  excited  through 
the  motor  nerves  of  the  muscles  concerned  in 
them.  Of  this  kind  are  not  only  the  irregular 
agitations  of  the  limbs  produced  by  tickling,  or 
the  convulsive  writhing  of  the  body  from  pain, 
but  also,  such  regular  and  admirably  precise 
movements  as  shrinking  when  pain  is  excited 

*  See  Mayo's  Outlines,   2d  edit.  p.  50  ct  scq. 
and  Sir  C.  Bell,  Phil.  Trans.  1826. 


718 


CONTRACTILITY. 


on  the  surface,  closing  the  eyelids  when  the 
eyes  are  offended  by  bright  light,  swallowing, 
breathing,  coughing,  sneezing,  vomiting,  ex- 
pulsion of  faeces  and  urine,  &c.  consequent 
on  certain  sensations  of  the  fauces,  lungs,  air- 
passages,  nostrils,  stomach,  rectum,  or  blad- 
der. Such  muscular  actions,  excited  by  irri- 
tation of  distant  parts,  have  been  generally  but 
vaguely  described  as  the  effects  of  Sympathies 
of  one  part  of  the  living  body  with  another. 
It  is  well  ascertained  that  they  are  effected 
through  the  motor  nerves  (or  certain  of  the 
motor  nerves)  of  the  muscles  concerned  in 
them ;  and  their  dependence  on  the  Sensations, 
and  therefore  on  the  sensitive  nerves,  of  the 
parts  from  the  irritation  of  which  they  originate, 
has  been  sufficiently  illustrated  by  Haller, 
Whytt,  Monro,  and  others.* 

It  has  also  been  observed,  by  Haller  and 
Whytt,  but  more  frequently  and  carefully  by 
Legallois,f  Flourens,  and  Mayo,J  that  in 
many  animals,  (most  remarkably  in  cold- 
blooded, or  young  warm-blooded  animals,) 
even  after  the  removal  of  the  brain,  as  long 
as  the  circulation  can  be  maintained,  move- 
ments of  the  kind  now  in  question  go  on, 
or  may  be  excited  by  irritation  of  the  sur- 
faces; and  that  if  the  spinal  cord  be  divided 
into  several  parts  by  transverse  sections,  such 
movements  may  still  be  excited  in  the  muscles 
supplied  from  each  part,  by  irritation  of  the 
portion  of  the  skin  which  has  its  nerves  from 
that  part  of  the  cord.  These  facts  have  (as  is 
believed)  usually  been  thought  to  denote,  that  a 
certain  degree  of  Sensation  remains  under  these 
circumstances,  in  connection  with  the  living 
state  of  the  spinal  cord,  or  of  portions  of  the 
spinal  cord,  and  medulla  oblongata,  indepen- 
dent of  the  brain ;  and  that  it  is  still  through 
the  intervention"  of  sensation,  that  irritation 
of  the  surface  of  the  body  excites  any  con- 
traction of  muscles.  Dr.  Marshall  Hall  has 
lately  described  phenomena  precisely  of  this 
description,  under  the  title  of  Excito-motory 
phenomena,  and  as  proofs  of  what  he  terms 
the  Reflex  Function  of  the  Spinal  Chord  § 
— a  power  of  exciting  contraction  in  mus- 
cular fibres  connected  with  it,  which  he 
supposes  that  organ  to  possess,  equally  inde- 
pendently of  sensation  as  of  volition ;||  and  as 
it  seems  hardly  possible  to  be  quite  certain  of 
the  existence  of  Sensation  in  the  case  of  the 
mutilated  animal,  this  language  is  perhaps 
philosophically  correct ;  but  the  probability  of 
the  existence  of  Sensation  in  such  circum- 
stances must  be  allowed  to  be  very  great ;  and 
at  all  events,  that  sensation  is  an  essential  part  of 

*  It  is  obvious  that  such  motions,  excited  di- 
rectly by  sensations,  cannot  be  accurately  distin- 
guished from  those  voluntary  actions  which  are 
called  Instinctive,  as  being  prompted  by  the  in- 
stincts, distinct  from  strictly  intellectual  acts, 
which  are  linked  by  nature  with  the  sensations  of 
certain  parts  of  the  body. 

t  Experiences  sur  le  Principe  de  la  Vie, 

$  Outlines  of  Physiology,  second  edit.    p.  282 
and  Anat.  and  Physiol.  Comms. 

§  Phil.  Trans.  1833,  p.  635. 

I]  See  particularly  p.  640. 


the  connection  between  the  irritation  of  distant 
parts,  and  the  excitement  of  involuntary  mus- 
cular contractions  of  voluntary  muscles,  for 
useful  purposes,  in  the  entire  and  healthy 
body, — may  be  held  to  be  a  point  well  esta- 
blished by  the  observations  of  Haller,  Whytt, 
Monro,  and  others,  on  such  sympathetic  actions. 
Accordingly,  those  actions,  in  the  entire  body, 
which  Dr.  M.  Hall  ascribes  to  the  reflex  func- 
tion,* are  the  same,  or  similar  to  those,  which 
have  been  fully  treated  by  Dr.  Whytt  and  others 
as  sympathetic  actions,  or  actions  of  voluntary 
muscles  excited  by  sensations. 

But  Dr.  Hall  has  fixed  the  attention  of  phy- 
siologists on  this  class  of  facts,  and  has  illus- 
trated by  experiments  their  independence  of 
the  Brain,  and  dependence  on  the  Spinal  Cord 
exclusively,  and  in  this  conclusion  he  is  sup- 
ported by  many  facts  previously  recorded  by 
Le  Gallois,  Magendie,  Flourens,  and  others. 

It  is  further  to  be  observed,  that  the  contrac- 
tions of  voluntary  muscles,  which  are  supplied 
by  the  nerves  of  the  Symmetrical  class  of  Sir 
C.  Bell,  while  they  are  excited  through  the  one 
set  of  filaments  comprising  those  nerves,  are 
made  known  to  our  consciousness  by  the  others 
or  sensitive  filaments,  and  constitute  the  im- 
portant class  of  Muscular  Sensations.  Of  the 
movements  of  the  strictly  involuntary  muscles, 
the  heart,  stomach,  and  bowels,  and  even  the 
bladder,  (supplied  by  irregular  nerves,)  we 
have,  in  the  perfectly  healthy  state,  no  intima- 
tion, although  they  frequently  become  percepti- 
ble to  us  in  disease,  or  when  over-excited.  But 
contractions  of  some  of  these  involuntary  mus- 
cles also  are  pretty  certainly  excited  by  certain 
Sensations,  as,  e.  g.  a  certain  degree  of  antipe- 
ristaltic  movement  in  the  stomach  by  the  feel- 
ing of  nausea,  and  a  certain  movement  of  the 
pharynx  and  oesophagus  by  the  sensations  in 
the  fauces,  which  prompt  the  act  of  deglutition ; 
and  in  such  cases,  although  not  attended  with 
consciousness,  they  are  in  all  probability  excited 
through  the  nerves  of  these  muscular  parts. 
Accordingly,  the  pharynx  and  oesophagus  have 
been  observed  by  Mr.  Mayo,  and  the  stomach 
by  Breschet,  Milne  Edwards,  and  others,  to 
be  exceptions  to  the  general  rule  of  involuntary 
muscles  being  inexcitable  by  irritation  of  their 
nerves. 

The  old  distinction  of  muscles  into  Volun- 
tary, Involuntary,  and  Mixed,  is  very  deficient 
in  precision,  so  far  as  the  last  class  is  concerned. 
The  true  distinction  is,  of  muscular  contrac- 
tions, into  those  excited  in  the  natural  state  by 
Mental  Stimuli,  and  through  the  intervention 
of  Nerves  (qui  soli  in  corpore  mentis  sunt  mi- 
nistri) — and  those  excited  by  Physical  Stimuli, 
acting  on  the  muscles  themselves,  whereas  the 
intervention  of  nerves  is  a  theory,  not  an  esta- 
blished fact.  The  first  class  admits  obviously, 
from  what  has  been  stated,  of  a  division  into 
movements  excited  by  the  Will,  which  depend 
on  the  Brain,  and  movements  excited  by  invo- 
luntary mental  acts,  especially  by  Sensations, 
which  depend  only  on  the  Spinal  Cord  and 
medulla  oblongata.  The  Will  acts  only  on 

*  P.  653  et  seq. 


CONTRACTILITY. 


719 


muscles  provided  with  sensitive  nerves,  by 
which  the  mind  is  informed  of  the  contractions, 
and  so  enabled  to  regulate  or  guide  them.  The 
Sensations  act  chiefly  on  this  description  of 
muscles  likewise,  but  partly  also  on  muscles 
the  nerves  of  which  give  no  such  distinct  inti- 
mation of  their  contractions,  and  which  are 
uniformly  and  strictly  involuntary;  and  the 
chief  excitants  of  this  last  class  of  muscles  in 
the  Animal  Economy  are  physical  stimuli,  ap- 
plied to  themselves  and  to  their  lining  mem- 
branes. 

II.  In  regard  to  the  vital  power  or  property 
of  Irritability,  as  exhibited  in  any  of  these  ways, 
the  following  facts  demand  particular  notice. 

1.  The  minutest  fibres,  of  which  the  mus- 
cles, exhibiting  this  property,  consist,  or  what 
have  been  called  by  some  authors  the  primary 

filaments  of  muscular  fibres,  appear  under  the 
microscope  to  consist  of  rows  of  globules,  or 
at  least  to  be  marked  by  transverse  striae,  at 
equal  distances. 

2.  When  contraction  takes  place,  these  fila- 
ments, or  rows  of  globules,  are  thrown  into  a 
zigzag  form ;  the  angles  being  always  at  the 
same   points  on  each  contraction,   and   being 
generally  obtuse,  rarely  and  only  on  occasion 
of  very  forcible  contraction,  acute.*     At  the 
points  where  these  angles  are  formed,  the  fila- 
ments are  crossed,  according  to  the  observa- 
tion of  Prevost  and  Dumas,  by  nervous  fibrils; 
but  it  is  important  to  remember,  that  this  last 
observation  has  been  made  only  on  muscles 
of  voluntary  motion,    and   on  them   only  in 
cold-blooded  animals,  where  they  are  somewhat 
translucent. 

3.  According  to  the  best  observations,  not 
made  on  entire  limbs  or  even  entire  muscles, 
which  involve  various  fallacies,  but  on  small 
portions   of   muscles,    removed    from    living 
bodies,  it  appears  that  no  alteration   of  the 
bulk  of  the  filaments  attends  this  alteration  of 
their  form,  so  that  neither  the  size  nor  distance 
of  the   particles   or  globules   appears    to  be 
changed,   but  merely  their  position  in  regard 
to  one  another .f 

4.  When  by  any  stimulus,  applied  to  mus- 
cular fibres,  the  filaments  directly  stimulated 
are  thrown  into  action,  the  contractions  very 
generally  and  rapidly  extend  to  many  others 
in  their  neighbourhood,  frequently  even  to  the 
whole  muscle  of  which  they  form  a  part ;  but 
the  contractions  of  single  fibres  appear  to  be 
of  short  duration,    and    the  more   enduring 
efforts  to  be  made  by  many  short  successive 
contractions  and  relaxations  or  vibrations    of 
the  individual  fibres. 

From  these  facts  it  would  appear,  that  each 
exertion  of  this  property  of  Irritability  essen- 
tially consists  in  a  greatly  increased  attraction 
among  the  particles  or  globules  constituting 

*  This  appearance,  with  slight  variations,  has 
been  repeatedly  seen,  both  in  warm-blooded  and 
cold-blooded  animals,  in  the  lower  classes  and 
even  in  the  infusory  animals,  under  the  micro- 
scope. 

t  See  Prevost  and  Dumas,  in  Journal  de  Phy- 
siologic, torn.  iii.  j  and  Mayo's  Outlines. 


the  muscular  fibres,  and  alteration  of  the  di- 
rection in  which  this  attraction  acts, — rapidly 
communicated  from  one  particle  to  another, 
both  along  the  same  fibre,  and  among  adjacent 
fibres, — and  rapidly  succeeded  by  repulsion,, 
or  return  to  the  previous  state  of  the  cohesive 
attraction  existing  among  these  particles. 

When  a  muscular  mass,  consisting  of  many 
such  fibres,  is  thrown  into  this  kind  of  action, 
it  is  easy  to  understand  that  its  breadth  and 
thickness,  and  its  rigidity  or  resistance  to  com- 
pression will  be  increased ;  that  its  extremities 
will  be  approximated  ;  and  that  if  it  be  dis- 
posed around  a  cavity,  containing  a  fluid  and 
provided  with  an  outlet,  that  fluid  will  be 
expelled.  It  is  by  such  contractions,  that  all 
the  more  conspicuous  movements,  even  of  the 
organic  life,  of  the  higher  animals,  are  per- 
formed, and  that  their  locomotive  and  vocal 
powers  are  exerted ;  and  it  is  worth  while  to 
pause  for  a  moment  to  consider  the  almost  in- 
conceivable amount  of  moving  power,  and  ra- 
pidity of  motion,  which  various  facts  indicate 
in  muscles  thus  contracting,  whether  under  the 
influence  of  the  will,  or  from  other  stimuli. 

It  seems  well  ascertained  that  the  contrac- 
tions of  the  left  ventricle  of  the  human  heart, 
in  its  ordinary  unexcited  state,  are  sufficient  to 
expel  its  fluid  contents,  in  free  space,  a  dis- 
tance of  7£  feet,  and  to  balance  a  weight  of 
above  50  Ibs. ;  and  this  power  is  exerted  regu- 
larly more  than  once  in  every  second,  and 
often,  even  independently  of  disease,  twice  in 
every  second,  during  the  whole  of  human  life. 
The  ordinary  action  of  the  left  ventricle  of  the 
Whale's  heart  suffices  to  expel,  according  to 
Dr.  Hunter's  statement,  at  each  pulsation, 
above  ten  gallons  of  blood,  with  a  great  velo- 
city, through  a  tube  of  a  foot  in  diameter. 

Two  instances  given  by  Haller,  and  quite 
within  the  limits  of  ordinary  experience,  suf- 
ficiently exemplify  the  great  power  occasion- 
ally exerted  by  voluntary  muscles ;  and  which 
will  appear  the  more  extraordinary  when  it  is 
remembered,  that  the  direction  of  muscular 
fibres,  as  regards  the  line  in  which  they  are  to 
act, — the  points  of  their  insertion  into  the 
bones  they  are  to  move, — and  the  line  in 
which  they  act,  as  regards  the  motion  which 
they  give  to  these  bones, — are  all,  very  ge- 
nerally, such  as  to  render. their  action  dis- 
advantageous, and  require  a  greater  amount 
of  moving  power  than  might  otherwise  have 
been  necessary.  The  instances  recorded  are, 
the  case  of  a  man,  who  could  raise  a  weight 
of  300  Ibs.  by  the  action  of  the  elevator  mus- 
cles of  his  jaw;  and  that  of  a  slender  girl, 
afflicted  with  tetanic  spasm,  in  whom  the  ex- 
tensor muscles  of  the  back,  in  the  state  of 
tonic  contraction  or  opisthotonos,  resisted  a 
weight  of  above  800  Ibs.,  laid  on  the  abdomen 
with  the  absurd  intention  of  straightening  the 
body.  In  some  of  the  lowest  classes  of  ani- 
mals the  intensity  of  the  muscular  power  ap- 
pears to  be  greater  than  in  any  of  the  largest. 
Thus,  a  flea  has  been  known  to  leap  sixty  times 
its  own  length,  and  to  move  as  many  times 
its  own  weight. 


720 

Again,  the  rapidity  of  the  changes  of  po- 
sition of  the  component  particles  of  muscular 
fibres  may  be  estimated,  although  it  can 
hardly  be  conceived,  from  various  well-known 
facts.  The  pulsations  of  the  heart  can  some- 
times be  distinctly  numbered  in  children  at 
more  than  200  in  the  minute;  and  as  each 
pulsation  of  the  ventricles  occupies  only  one- 
third  of  the  time  from  the  commencement  of 
one  pulsation  to  the  commencement  of  the 
next,  this  implies  that  each  contraction  takes 
place  in  gigth  part  of  a  minute,  or  that  ten 
times  in  each  second,  for  many  hours  toge- 
ther, the  whole  of  the  convoluted  muscular 
fibres  of  the  ventricles  must  be  thrown  into 
folds,  and  again  smoothed  out.  Again,  it  is 
certain  that  by  the  movements  of  the  tongue 
and  other  organs  of  speech,  1500  letters  can 
be  distinctly  pronounced  by  some  persons  in 
a  minute.  Each  of  these  distinguishable 
sounds  must  require  a  separate  contraction  of 
muscular  fibres ;  and  the  production  and  ces- 
sation of  each  of  these  sounds  must  imply, 
that  each  separate  contraction  must  be  followed 
by  a  relaxation  of  equal  length.  Each  con- 
traction must,  therefore,  have  been  effected  in 
aouijth  part  of  a  minute,  or  in  the  50th  part  of  a 
second.  Haller  calculated  that  in  the  limbs 
of  a  dog  at  full  speed,  muscular  contractions 
must  take  place  in  less  than  the  200th  part  of 
a  second,  for  at  least  many  minutes  in  suc- 
cession.* 

But  the  property  of  Irritability,  which  acts 
throughout  so  great  a  portion  of  the  animal 
creation,  as  a  moving  power  of  this  extra- 
ordinary efficiency,  is  not  the  only  contractile 
power,  which  certain  organic  textures  possess, 
or  which  the  conditions  of  their  existence  re- 
quire them  to  exert  during  the  living  state. 
Even  in  muscular  fibres  themselves,  in  certain 
organs,  and  still  more  in  other  textures  of 
animal  bodies,  contractions  are  often  observed, 
peculiar  to  the  living  state,  but  differing  essen- 
tially from  those  which  come  under  the  defi- 
nition of  Irritability  already  given. 

In  all  the  different  tribes  of  animals,  indeed, 
differences  in  the  contractile  power  of  the  diffe- 
rent living  solids  may  be  observed,  exactly  cor- 
responding to  their  circumstances  and  wants. 
The  slow  and  languid  movements  of  the  bodies 
of  most  of  the  Zoophyta,  and  the  rapid  vibra- 
tions of  the  Ciliae  with  which  parts  of  many 
of  these  animals  (particularly  of  the  order 
Infusoria)  are  provided,  are  examples,  even 
in  the  lowest  class,  of  the  great  variety  of 
moving  powers,  with  which  the  living  solids 
of  different  animals  are  endowed. 

In  the  human  body,  and  analogous  animals, 
it  is  obvious  that  the  contractile  power  exerted 
by  the  stomach  and  intestines  in  performing 
their  peristaltic  movements,  although  of  the 
same  general  characters  as  that  of  the  heart, — 
the  contraction  of  each  portion  of  the  tube 
being  followed  by  a  relaxation  of  that  portion 
and  a  contraction  of  the  portion  next  in  ad- 
vance,— is  yet  materially  different ;  both  con- 

*  See  Haller's  Elcm.  Phys.  torn.  iv.  p.  481. 


CONTRACTILITY. 


traction  and  relaxation  in  the  peristaltic  move- 
ment being  of  longer  and  less  definite  du- 
ration, and  of  more  variable  extent.  In  the 
bladder  and  in  the  uterus,  in  the  healthy  state, 
we  see  contractions  excited  by  peculiar  stimuli, 
and  repeatedly  recurring  as  the  actions  de- 
pendent on  them  proceed,  but  not  alternating 
with  any  obvious  elongation  of  the  fibres,  and 
terminating  in  a  much  greater  and  more  per- 
manent shortening  of  the  contracting  fibres, 
than  is  observed  in  other  muscular  organs. 

Again,  in  the  state  of  any  voluntary  muscle, 
when  the  distance  of  its  extremities  is  per- 
manently shortened  (as  by  an  ill-united  frac- 
ture), in  that  of  the  sphincter  muscles,  or  of  an 
artery  when  emptied  of  blood,  we  see  a 
permanent  contraction,  requiring  no  stimulus 
to  excite  it,  shewing  itself  whenever  a  dis- 
tending or  elongating  power  is  withdrawn,  and 
relaxing  only  at  the  close  of  life.  The  nume- 
rous experiments  of  Dr.  Parry  on  the  condition 
of  arteries  immediately  after  death  (contained 
in  his  Treatise  on  the  Arterial  Pulse)  afford  the 
most  precise  information  that  we  have  as  to 
this  last  property. 

From  such  facts  it  appears  obvious  that 
three  distinct  modes  of  contraction,  all  strictly 
vital,  may  be  observed  in  different  textures  of 
the  body,  or  even  in  the  same  texture  under 
different  circumstances:  first,  that  already  con- 
sidered, to  which  the  term  Irritability  is  strictly 
applied,  and  which  is  best  exemplified  in  the 
actions  of  the  voluntary  muscles  and  the  heart ; 
secondly,  that  which  may  be  termed  simple 
Contractility,  where  contraction  is  induced  by 
a  stimulus,  but  takes  place  more  slowly,  and 
is  nearly  or  quite  permanent;  and,  thirdly, 
that  which  has  been  accurately  described  by 
Dr.  Parry  and  others  under  the  title  of  Toni- 
city,  which  requires  no  stimulus  to  call  it  into 
action,  but  takes  effect  whenever  a  distending 
power  is  withdrawn,  and  continues  until 
life  is  extinguished.  The  second  of  these 
forms  is  seen,  not  only  in  the  bladder  and 
uterus,  but  in  the  arteries  under  certain  irri- 
tations, perhaps  in  other  textures,  and  pro- 
bably also  (from  certain  stimuli)  in  the  fibrin 
of  the  blood  during  coagulation.*  The  last 
is  clearly,  as  Dr.  Parry's  experiments  have 
shewn,  the  chief  vital  endowment  of  arteries; 
and  notwithstanding  the  doubts  expressed  on 
the  subject  by  Dr.  Bostock,  several  facts  may 
be  stated  to  show,  that  it  is  also  an  endow- 
ment of  all  muscular  fibres.  Thus,  besides 
the  permanent  retraction,  already  noticed,  of 
the  fibres  of  a  muscle  the  fixed  extremities  of 
which  are  approximated, — the  retraction  of  the 
cut  ends  of  a  muscle  divided  during  life, — the 
state  of  habitual  preponderance  of  the  flexor 
muscles  of  the  body  and  limbs  (which  are  the 
stronger)  over  the  extensors  during  sleep,f  and 
the  stiffening  or  "  roideur  cadaverique  "  of  the 
muscles  after  death, — seem  to  be  clear  indica- 
tions of  a  tendency  to  contraction  answering 

*  SeePrater'sExperimental  Inquiries  iu  Chemical 
Physiology. 

t  See  Richcrand's  Physiology. 


CONTRACTILITY. 


721 


to  the  definition  of  Tonicity,  not  of  Irritability. 
This  hist  phenomenon,  as  it  disappears  before 
putrefaction  begins,  and  as  it  is  variously  in- 
fluenced by  causes  affecting  vital  action,  is 
allowed  to  be  a  last  exertion  of  vital  power. 

There  are  evidently  slighter  modifications  or 
varieties  of  the  powers  which  we  have  thus 
distinguished;  but  the  distinctions  now  stated 
seem  to  be  those  which  are  sufficiently  marked 
to  demand  separate  names.  Besides  the  mus- 
cular texture,  some  of  the  membranes,  espe- 
cially the  skin,  appear  to  be  endowed  with  a 
certain  degree  of  vital  contractile  power,  al- 
though not  with  true  Irritability.  It  is  remark- 
able, that  the  greatest  degree  of  contraction 
seen  in  muscular  fibres,  is  in  those  which  pos- 
sess the  property  of  simple  Contractility  rather 
than  Irritability,  viz.  in  the  bladder  and  uterus 
more  than  in  the  intestines,  and  in  these  more 
than  the  heart. 

III.  As  to  the  conditions,  necessary  to  the 
maintenance  of  the  contractile  powers  of  living 
parts,  it  is  in  the  first  place  obvious,  that  they 
are  always  dependent  on  the  maintenance  of 
the  organization  of  these  parts  themselves. 
When  the  muscles  waste,  as  from  rheumatic 
inflammation,  or  from  the  poison  of  lead,  as  in 
colica  pictonum,  or  when  their  texture  is  gra- 
dually altered,  as  by  inilammation  or  in  cer- 
tain organic  diseases  occasionally  affecting 
them,  or  more  rapidly  relaxed  and  injured  by 
over-distension,  they  lose  their  contractile 
power  more  or  less  completely;  and  their 
power  is  likewise  gradually  diminished  in  old 
age,  as  their  texture  partakes  of  the  gradually 
increasing  rigidity. 

Like  all  other  vital  actions,  the  contractions 
of  moving  parts  are  more  immediately  depen- 
dent on  the  maintenance  of  a  certain  tempe- 
rature, varying  in  the  different  tribes  of  ani- 
mals,— in  all  the  warm-blooded  (in  the  state 
of  activity)  probably  confined  within  the  de- 
grees of  00  and  120  of  Fahrenheit.  They 
are  dependent  also  on  the  regular  supply  of 
arterial  Blood.  The  experiments  of  Stenon 
and  others  have  shewn,  that  the  power  of 
muscles  is  rapidly  extinguished  when  the  ar- 
teries supplying  them  are  tied.  It  has  gene- 
rally been  supposed,  since  the  time  of  Bichat, 
that  venous  blood,  when  it  penetrates  muscular 
fibres,  is  equally  or  even  more  rapidly  noxious 
to  them,  than  the  denial  of  the  supply  of 
arterial  blood ;  but  the  experiments  of  Dr.Kay* 
have  shewn,  that  the  contractile  power  of  mus- 
cles, when  failing  from  this  latter  cause,  may 
be  restored  by  the  influx  of  venous  blood,  al- 
though in  a  less  degree  than  by  arterial, — 
and  Dr.  Marshall  Hall  has  observed,  that  in 
hybernating  animals  whose  respiration  is  sus- 
pended, the  flow  of  venous  blood  through  all 
the  textures  continues,  and  keeps  up  a  certain 
degree  of  muscular  power  ;  so  that  the  venous 
blood  can  only  be  regarded  as  less  powerful  in 
maintaining  the  irritability  of  muscles  than 
arterial  blood  (probably  because  it  is  incapable 

*  Edin.  Med.  and  Surg.  Journal,  vol.  xxviii. 
and  Treatise  ou  .•)  sj-hyxia,  ch.  iii. 


of  affording  them  nourishment),  not  as  posi- 
tively deleterious  to  them.  The  act  of  healthy 
Nutrition,  by  arterial  blood,  is  therefore  the 
main  condition  of  the  vital  power  of  muscles, 
as  of  all  other  living  solids.  And  it  is  im- 
portant to  remember  that  this  vivifying  in- 
fluence of  the  living  blood  on  the  solids  is 
evidently  reciprocal ;  for  when  any  of  the 
vessels  containing  blood  lose  their  vitality,  as 
from  injury,  the  blood  then  coagulates,  as  if 
drawn  from  the  body. 

There  is  a  remarkable  difference  which  has 
been  long  observed,  in  the  different  classes  of 
animals,  and  even  in  the  different  states  of  the 
same  animals,  as  to  the  consumption  of  oxygen 
by  the  blood  on  one  hand,  and  the  indications 
of  muscular  power  on  the  other.  The  activity 
of  muscular  power  (as  indicated  by  the  rapi- 
dity of  the  circulation  and  the  energy  of  vo- 
luntary muscular  exertions)  appears  to  be,  in 
general,  in  direct  proportion  to  the  amount 
of  action  between  the  air  and  the  blood,  being 
greatest  in  birds,  greater  in  the  mammalia  than 
in  reptiles  or  fishes;  and  greater  in  insects, 
where  air  is  freely  admitted  into  the  interior 
of  the  body,  and  applied  to  the  blood,  than  in 
the  Zoophyta,  or  even  the  Mollusca,  where 
there  is  less  exposure  of  the  blood  to  the  air ; 
and  again,  being  greater  in  perfect  animals 
than  in  eggs  or  pupae,  and  greater  in  animals 
in  a  state  of  activity  than  in  those  in  a  state 
of  torpor  or  hybernation.  But  on  the  other 
hand,  the  endurance  of  the  muscular  power, 
or  tenacity  of  life,  in  whatever  manner  the 
vital  principle  is  depressed  or  extinguished, 
is  generally  in  the  inverse  ratio  of  the  activity 
of  muscular  contractions,  and  of  the  amount 
of  mutual  action  between  the  air  and  the  blood. 
Thus  the  tenacity  of  life  in  reptiles  and  fishes 
is  well  known  to  be  greater  than  in  mammalia 
or  birds, — in  some  of  the  lower  classes,  par- 
ticularly the  infusory  animalcules,  much  greater 
than  in  any  of  the  higher ;  in  very  young  ani- 
mals greater  than  in  adults;  and  in  hyberna- 
ting animals,  in  eggs,  and  pupae,  greater  than 
in  any  perfect  animals. 

Dr.  Marshall  Hall  has  observed,  that  in 
some  of  the  lower  classes  of  animals,  such  as 
Reptiles,  the  degree  of  muscular  contraction 
induced  by  stimuli,  as  well  as  its  duration, 
is  greater  than  in  the  warm-blooded  animals ; 
and  he  has  hence  been  led  to  lay  down  as  a 
general  principle  the  reverse  of  what  has  com- 
monly been  stated,  viz.  that  the  Irritability  of 
muscular  fibres  is  inversely  as  the  quantity  of 
Respiration.  But  this  proposition  seems  to 
be  too  generally,  if  not  incorrectly,  expressed. 
It  seems  an  unnecessary  innovation  in  language, 
to  assert  that  the  irritability  of  muscular  fibres 
is  inversely  as  the  activity  of  muscular  con- 
tractions, or  that  the  irritability  in  insects, 
where  the  blood  is  fully  exposed  to  the  air, 
is  less  than  in  the  Zoophyta,  where  there  is 
much  less  provision  for  respiration.  In  fact, 
the  vital  powers  of  contractile  parts  vary  so 
much  in  different  organs,  even  of  the  same 
animal,  that  it  may  be  doubted  whether  any 
other  general  proposition  can  be  laid  down  as 


722 


CONTRACTILITY. 


to  its  connexion  with  respiration,  than  that  of 
the  greater  activity  of  muscular  action,  on  the 
whole,  in  those  animals  where  there  is  much 
exposure  of  the  blood  to  the  air,  and  the 
greater  endurance  or  tenacity  of  life  where  there 
is  little. 

The  question,  how  far  the  Nervous  System 
furnishes  one  of  the  conditions  necessary  to 
the  maintenance  of  the  contractile  power  of 
muscles,  has  long  engaged  the  attention  of 
physiologists,  and  been  the  occasion  of  much 
erroneous  medical  theory ;  but  in  the  present 
state  of  the  science,  need  not  occupy  much  of 
our  attention. 

The  doctrine  of  Cullen  and  many  other 
systematic  writers,  that  the  muscles  derive  re- 
gular supplies  of  Irritability  or  vital  power, 
through  the  nerves,  from  the  larger  masses  of 
the  nervous  system,  seems  to  be  now  pretty 
generally  abandoned,  although  the  terms  Ner- 
vous Influence  or  Energy  are  still  suffered  to 
retain,  in  the  language  of  many  medical 
writers,  a  vague  and  indefinite  meaning, 
derived  from  that  apparently  erroneous  theory. 
When  we  remember,  that  after  the  nerves 
of  a  muscle  are  cut,  the  muscle  continues 
irritable  under  stimuli  applied  to  itself,  or  to 
the  portions  of  nerves  below  the  section, 
as  long  as  it  retains  its  organization  unim- 
paired,— that  section  of  the  nerves  leading  to 
the  heart  has  in  very  numerous  experiments 
been  found  to  produce  little  or  no  effect  on  its 
movements, — that  these  movements  continue 
for  hours  after  the  head  has  been  cut  off,  or 
even  (as  was  first  shewn  by  Dr.Wilson  Philip) 
after  both  brain  and  spinal  cord  have  been 
removed  from  the  body,  provided  that  the  flow 
of  the  blood  through  the  lungs  is  maintained 
by  means  of  the  artificial  respiration, — that  in 
hybernating  animals  (as  Dr.  M.  Hall*  has 
ascertained)  when  respiration  is  at  a  stand, 
the  regular  movements  of  the  heart  may  con- 
tinue for  nine  hours  after  the  gradual  but  com- 
plete destruction  of  the  whole  brain  and  spinal 
cord, — and  that  there  are  many  instances  on 
record,  of  the  human  fetus  having  come  to  a 
full  size  (implying  long-continued  and  regular 
action  of  the  heart),  where  neither  brain  nor 
spinal  cord  existed,-}- — it  seems  impossible  to 
maintain  the  purely  hypothetical  proposition, 
that  the  irritability  of  muscles  is  dependent 
on  an  influence  or  energy  continually  flowing 
to  them  from  the  brain  or  spinal  cord ;  J  and 

*  Philosophical  Transactions,  1832 

t  See  Brachet's  Recherr.hes  sur  le  Systeme  Ner- 
veaux,  p.  36  &  seq. 

$  Mr.  J.  W.  Earle,  in  a  "  New  Exposition  of  the 
Functions  of  the  Nerves,"  has  attempted  to  revive 
this  theory.  He  trusts  chiefly  to  an  experiment, 
in  which  the  irritability  of  muscles,  exhausted  by 
repeated  irritation,  was  not  recovered  after  their 
nerves  had  been  cut.  But  this  experiment  is  incon- 
clusive, because  the  muscles  had  become  inflamed 
and  disorganized — (See  p.  70  and  71  of  his  work.) 
This  experiment  has  been  lately  repeated  in  Edin- 
burgh, with  precautions  to  prevent  the  inflam- 
mation of  the  muscles,  and  the  result  was  the 
reverse  of  that  obtained  by  Mr.  Earle. — See  Trans- 
actions of  British  Association,  1834. 


the  only  question  that  can  remain  is,  whether 
the  irritation  of  muscles  is  always  effected 
through  the  medium  of  nerves,  i.  e.  whether 
every  stimulus  which  excites  contraction  in  a 
muscle  first  acts  on  some  of  the  nervous 
fibrils  which  enter  it,  and  by  exciting  them 
throws  the  muscular  fibres  into  action.  An  ex- 
periment of  Brachet*  has  been  thought  to 
furnish  evidence  of  the  dependence  of  the 
heart's  actions  on  the  cardiac  plexus  of  nerves, 
but  is  so  liable  to  fallacy,  and  so  much  op- 
posed to  the  experience  of  others,  on  the  effect 
of  injuries  of  the  cardiac  nerves,  that  the  in- 
ference seems  to  have  been  generally  dis- 
trusted. 

Without  presuming  to  decide  absolutely  on 
a  question  which  still  divides  the  opinions  of 
physiologists,  and  without  entering  on  various 
arguments  which  have  been  stated  as  furnishing 
probable  evidence  either  on  the  one  side  or  the 
other,  we  may  observe, —  1.  That  the  safe 
logical  rule  in  such  cases,  is  "  Affirmantibus 
incumbit  probatio ;"  and  therefore  it  does  not 
appear  philosophical  to  teach,  that  the  con- 
traction of  all  muscles,  on  stimuli  being  ap- 
plied to  themselves,  is  owing  to  the  inter- 
vention of  nerves,  until  that  intervention  be 
proved.  2.  That  if  the  contraction  of  all 
muscles  were  excited  through  nerves,  we  might 
expect  to  find  all  muscles  supplied  with  nerves, 
the  mechanical  irritation  of  which,  in  the  li- 
ving or  newly  killed  animal,  should  excite 
that  contraction.  But  it  has  been  already 
observed,  that  in  the  case  of  the  involuntary 
muscles,  physical  irritation  of  the  nerves  en- 
tering them  (if  strictly  confined  to  the  nerves) 
has  very  generally  been  found  quite  ineffectual 
for  that  purpose.  This  seems  pretty  clearly  to 
indicate,  that  the  power  of  exciting  muscular 
fibres  to  contraction  is  an  endowment  peculiar 
to  the  nerves  of  the  voluntary  muscles,  or  at 
least  enjoyed  by  them  in  a  much  greater  de- 
gree than  by  others,  and  designed,  not  to 
render  these  muscles  irritable,  but  merely  to 
subject  their  irritability  to  the  dominion  of  the 
Will. 

The  observation  of  Fontana  on  this  subject, 
made  as  early  as  1775,  and  in  perfect  accord- 
ance with  the  statements  of  Haller  previously, 
and  of  many  other  physiologists  subsequently, 
may  still  be  quoted  as  more  conclusive  than 
any  other  which  has  since  been  brought  for- 
ward. "  If  you  open  the  chest  of  an  animal, 
(a  cold-blooded  one  answers  best  for  the  ex- 
periment) and  stimulate  as  you  please  the 
nerves  going  to  the  heart,  that  muscle  will 
neither  accelerate  its  movements  if  it  be 
moving,  nor  resume  them  if  it  be  at  rest, — 
even  although  it  be  prone  to  immediate  con- 
traction on  its  own  fibres  being  touched.  The 
nerves  of  the  heart,  therefore,  are  in  no  sense 
the  organs  of  the  movement  of  this  muscle,  as 
they  are  of  other  muscles.  This  experiment  is 
certain,  and  the  inference  direct.  It  would  be 
a  contradiction  to  assert  that  the  movements  of 
the  heart  take  place  through  the  intervention  of 

*  Loc.  cit.  p.  125. 


CONTRACTILITY. 


723 


nerves,  when   experiment  shews  that  nerves 
cannot  excite  these  movements." 

IV.  In  regard  to  the  laws,  by  which  the 
vital  powers  of  contractile  parts  may  be  regu- 
lated, we  have  probably  much  to  learn  ;  but 
three  sets  of  facts  have  been  observed,  which 
may  at  present  be  regarded  as  general  laws  in 
this  department  of  physiology. 

1.  Notwithstanding  what  has  been  said  of 
the  contractility  of  muscles  being  independent 
of  any  influence  continually  flowing  to  them 
from  the  brain  or  spinal  cord,  it  is  well  ascer- 
tained that  in  a  living  and  entire  animal,  where 
all  the  functions  of  the  body  are,  for  wise  and 
important  purposes,  made  liable  to  change, 
from  changes  in  the  nervous  system,  the  con- 
tractile power  of  various  moving  parts  is  sub- 
ject to  increase  or  diminution  from  physical 
causes  acting  in  these  larger  masses  of  the  ner- 
vous system,  just  as  they  are  from  various  acts 
and  affections  of  Mind,  the  effects  of  which 
may  be  said  to  be  imitated  by  those  physical 
causes.  Thus  in  the  experiments  of  Le  Gallois, 
of  Dr.  Wilson  Philip,  of  Flourens,  and  others, 
suddenly  crushing  any  large  portion,  either  of 
the  brain  or  spinal  cord,  has  been  found  uni- 
formly to  depress  or  even  extinguish  the  power 
of  the  heart ;  the  well-known  fatal  effect  often  ob- 
served from  sudden  violent  injury  of  the  epi- 
gastrium in  the  human  body,  has  been  ascribed 
with  probability  to  the  injury  of  the  great  semi- 
lunar  ganglion  ;  and  the  depression  of  the 
heart's  action  which  attends  Concussion,  and 
which  is  the  immediate  cause  of  death  in  the 
most  quickly  fatal  cases  of  that  kind,  is  also 
generally  regarded  as  an  impression,  made  ori- 
ginally on  the  nervous  system,  and  immediately 
transmitted  to  the  heart.  On  the  other  hand, 
slighter  and  more  continued  physical  irritations 
of  the  nervous  system  appeared  in  many  expe- 
riments, especially  of  Dr.  Wilson  Philip,  to 
augment  the  irritability  of  the  heart.  It  is  true 
that,  in  all  these  cases,  some  have  supposed  the 
effects  of  the  violence  to  be  on  the  organs  of 
circulation  directly,  and  not  through  the  inter- 
vention of  the  nerves ;  but  when  it  is  remem- 
bered, that  some  of  those  injuries,  which  are 
the  most  rapidly  fatal  to  the  heart's  actions, 
(such  as  the  pushing  of  a  probe  along  the 
spinal  canal,)  do  not  necessarily  imply  any 
great  violence  to  the  body  at  large ;  and  further, 
that  precisely  similar  effects  on  the  heart's  ac- 
tion (both  increase  and  diminution)  often  result 
from  mental  emotions  and  passions,  which  cer- 
tainly act  first  on  the  nervous  system,  the  ac- 
count which  we  give  of  the  mode  of  action  of 
these  causes  appears  to  be  sufficiently  con- 
firmed. 

One  cause,  acting  primarily  on  the  nervous 
system,  which  seems  to  have  a  peculiar  de- 
pressing effect  on  the  heart's  action,  is,  sudden  re- 
moval of  the  pressure  to  which  the  brain  had 
previously  been  subjected.  The  effect  of  this 
on  the  heart  has  been  repeatedly  seen  in  surgi- 
cal operations  ;  and  this  seems  to  be  an  essen- 
tial part  of  the  pathology  of  several  cases  of 
syncope,  particularly  of  that  which  results, 
either  from  bloodletting  in  the  erect  posture, 
or  from  tapping  in  ascites. 


It  is  very  remarkable  that  the  heart,  which 
is  so  strictly  an  involuntary  muscle,  and  so 
little  liable  to  excitation  by  stimuli  applied 
to  its  nerves,  is  much  more  liable  than  the 
voluntary  muscles  both  to  sudden  increase 
and  to  diminution,  or  even  total  loss,  of  vital 
power  from  such  causes  as  we  have  now 
considered.  But  a  little  reflection  will  shew, 
that  the  direct  stimulation  of  a  muscle,  and  the 
increase  or  diminution  of  its  irritability,  are 
perfectly  distinct  cases.  And  we  may  approxi- 
mate, at  least,  to  an  explanation  of  the  peculiar 
liability  of  the  heart  (and  probably  of  other 
involuntary  muscles)  to  the  influence  of  such 
causes  acting  through  the  nervous  system,  as 
augment  or  depress  the  vital  power,  when  we 
remember  two  facts  :  1.  that  the  causes  which 
act  in  this  way  are  very  generally  such  as  are 
applied  to  large  portions  of  the  brain  or  spinal 
cord  ;*  and  2.  that  the  arrangements  of  the 
ganglionic  nerves  are  such  as  to  place  the  heart 
and  other  organs  supplied  from  the  ganglia,  in 
connexion  with  the  whole  extent  of  the  cerebro- 
spinal  axis,  and  hardly  with  any  individual  part 
of  it  more  than  another. 

2.  There  are  various  external  agents,  by  the 
application  of  which  the  vital  power  of  con- 
tractile parts,  and  especially  of  the  heart, — the 
main  agent  in  the  circulation, — may  be  altered 
or  even   destroyed.     It  is  increased,  not  only 
by  moderate  increase  of  the  Temperature  in 
which  living  parts  are  kept,  and  of  the  quantity 
of  arterial  blood  sent  to  them,  but  also  by  Elec- 
tricity applied  in  a  low  degree  of  intensity,  and 
by  various  articles  of  diet  and  medicinal  agents, 
such  as  the  various  preparations  of  Alcohol; 
and  it  is  diminished,  or  even  suddenly  extin- 
guished often  by  the  same  agents  applied  in 
excess,  (as  in  the  case  of  Lightning  when  most 
rapidly  fatal,)  and  still   more  remarkably  by 
certain  Poisons,  such  as  the  upas  antiar,  tobacco, 
digitalis,  arsenic,  and  hydrocyanic  acid.     It  is 
still  doubtful  through  what  medium  these  poi- 
sons act  on  the  vital  power  of  the  heart ;  but  it 
is  certain  that  the  effect  which  they  produce  on 
that  power  is  the  immediate  cause  of  the  death 
resulting  from  them.f 

In  cases  of  the  most  sudden  death  produced 
by  such  causes  acting  in  the  utmost  inten- 
sity, the  contractile  power  in  the  voluntary 
muscles,  as  well  as  in  the  heart,  has  been  found 
to  be  very  much  diminished  or  even  nearly  ex- 
tinguished; and  it  is  very  important  to  observe, 
that  in  such  cases  the  property  of  coagulation 
in  the  blood  is  likewise  lost;  which  seems 
clearly  to  indicate  (what  various  other  facts 
confirm)  that  this  change  in  the  blood  is  de- 
pendent on  the  existence  in  that  fluid  of  a 
certain  degree  of  the  same  vital  properties,  to 
which  we  give  the  name  of  Contractility  as  ex- 
isting in  the  solids. 

3.  The  contractile  power  of  living  parts  is 
liable  to  much  alteration  from  the  degree  in 


*  See  Dr.  Wilson  Philip's  Experimental  Inqui- 
ries, &c.  ch.  ii.  and  iv. 

t  The  terms  Stimulant  and  Sedative  are  applied 
most  correctly  to  those  agents  which  thus  exalt  or 
depress  the  vital  actions  of  the  circulating  system. 


724 


CRANIUM. 


which  it  is  itself  exercised.  The  immediate 
effect  of  frequently  repeated  stimulation  of  a 
voluntary  muscle,  whether  by  physical  or  mental 
stimuli,  in  a  living  or  newly  killed  animal,  is 
gradual  diminution  or  ultimate  extinction,  or 
what  is  usually  called  Exhaustion  of  its  Irri- 
tability ;  which  is  gradually  restored  when  the 
stimulation  is  discontinued  and  the  muscle  is 
at  rest. 

But  the  theoretical  conclusions  which  have 
been  drawn  from  this  fact  have  greatly  exceeded 
the  legitimate  inferences.  It  is  by  no  means 
clear  that  such  increased  action  of  involuntary 
muscles,  as  results  from  causes  of  the  kinds 
just  mentioned,  which  exalt  or  increase  their 
contractile  power,  is  necessarily  followed  by 
any  corresponding  depression.  On  the  con- 
trary, in  the  case  of  violent  exercise,  in  many 
instances  of  mental  agitation  and  excitement, 
and  in  the  course  of  certain  febrile  and  inflam- 
matory diseases,  we  see  the  heart's  action 
greatly  and  permanently  increased,  without 
evidence  of  any  subsequent  loss  of  power  which 
can  reasonably  be  ascribed  merely  to  the  cir- 
cumstance of  increased  action. 

It  is  true  that  the  effect  of  many  stimulating 
substances,  such  as  alcohol,  is  first  to  excite, 
and  after  atime  to  weaken  or  depress,  the  actions 
of  the  heart  and  circulating  system  ;  but  as  we 
know  that  an  equal  or  greater  degree  of  excite- 
ment from  exercise,  from  exciting  passions  of 
mind,  or  from  inflammatory  disease,  may  exist 
without  producing  any  such  subsequent  de- 
pression, we  ought  to  regard  the  loss  of  power 
which  follows  the  excessive  use  of  such  sub- 
stances, as  an  ulterior  effect  of  these  substances 
themselves,  rather  than  as  the  result  of  the  mere 
circumstance  of  previous  increased  action.* 
Although,  therefore,  we  consider  all  exertions 
of  the  irritability  of  muscles  as  necessarily  im- 
plying intervals  of  relaxation,  and  are  aware  of 
the  exhaustion  of  irritability  by  excessive  sti- 
mulation, yet  we  do  not  see  that  the  operation 
of  those  agents  which  augment  the  vital  power, 
particularly  of  the  involuntary  muscles,  is  ne- 
cessarily followed  by  a  corresponding  loss  of 
power. 

Further,  it  has  been  often  alleged  that  the 
vital  power  of  Irritability  is  not  only  expended 
or  exhausted  by  excessive  action,  but.  likewise 
increased  or  accumulated  by  rest.  But  there  is 
no  evidence  whatever  that  rest  does  more 
than  merely  restore  the  power  that  had  been 
lost  by  previous  exertion.  A  muscle  or  set  of 
muscles  which  has  been  weakened  by  excessive 
excitement,  and  regained  its  power  by  rest, 
may  remain  quiescent  for  an  indefinite  time 
thereafter,  and  will  not  only  not  continue  to 
gain  power,  but  will  gradually  lose,  after  a 
time,  that  which  it  had  previously  possessed. 
The  idea  of  the  accumulation  of  Irritability  by 
long-continued  inaction  has  been  thought  to  be 
supported  by  the  fact,  that  the  stimulating 
effect  of  Heat  on  all  vital  action,  is  greatest 
when  it  is  applied  after  long-continued  Cold. 
But  this  seems  manifestly  to  be  owing  to  the 

*  See  Gregory's  Conspectus,  art.  De  Remediis 
Stimulant!  bus. 


principle  that  the  stimulating  effect  of  heat  on 
vital  action  is  proportioned,  not  merely  to  the 
temperature  that  may  be  applied,  but  chiefly 
to  the  degree  of  change  of  temperature  under- 
gone in  a  given  time;  of  which  point  many 
illustrations  might  be  given,  and  which  neces- 
sarily implies  that  the  effect  of  Heat  must  be 
much  increased  by  its  I  eing  applied  after  Cold. 
Another  law,  which  may  be  deduced  from 
observation  of  repeated  exertion  of  living  con- 
tractile parts,  is  of  great  importance  both  in 
physiology  and  pathology;  viz.  that  the  ulti- 
mate effect  of  such  repeated  exertion,  with 
sufficient  intervals  of  repose,  is  to  augment  both 
the  hulk  and  strength  of  muscular  fibres,  and 
facilitate  the  subsequent  excitation  of  vital 
action,  whether  in  voluntary  or  involuntary 
muscles.  This  is  seen  in  the  state  of  hyper- 
trophy of  the  muscular  fibres  of  the  arms  of 
labourers,  of  the  legs  of  dancers, — of  the  heart, 
in  those  who  have  disease  of  the  valves  of  the 
aorta, — of  the  bladder,  in  those  who  have 
disease  of  the  prostate  gland  or  stricture  of  the 
urethra ;  and  is  in  fact  only  a  part  of  a  more 
general  law, — that  the  habitual  exertion  (within 
limits  consistent  with  health)  of  all  vital 
powers,  is  naturally  attended  with  an  increased 
flow  of  blood  to  the  organs  exerting  those 
powers,  and  with  an  increase  of  their  nutrition. 
And  the  counterpart  of  this  is  seen  in  the  very 
slow  and  gradual,  but  ultimately  extreme  dimi- 
nution, not  only  of  the  vital  properties,  but  of 
the  bulk  and  characteristic  appearance,  of  mus- 
cular parts  which  have  been,  from  any  cause, 
kept  very  long  in  a  state  of  absolute  inaction. 
According  to  the  observation  of  Andral,  the 
structure  of  muscles  may  in  these  circum- 
stances be  so  altered,  that  they  become  ulti- 
mately hardly  distinguishable  from  cellular 
texture.  The  act  of  Nutrition,  and  therefore  the 
organization  of  muscular  fibres,  as  well  as  of 
other  living  parts,  is  manifestly  intended  by 
nature  to  be,  in  a  certain  degree,  dependent  on 
the  exertion  of  their  own  vital  power ;  and  one 
effect  of  that  exercise  of  vital  power  is  to 
solicit  or  attract  the  living  fluid  to  the  part 
concerned  in  it,  in  a  manner  which  the  re- 
searches of  physiologists  have  not  yet  satisfac- 
torily elucidated. 

(  W.  P.  Alison.) 

CRANIUM  (in  anatomy)  Gr.  tt^anov ;  Fr. 
Crane;  Germ.  H irnschadel ;  Ital.  Cranio. 

The  cranium  is  the  protective  investment  of 
the  brain,  on  which  it  is  moulded,  and  the 
form  of  which,  in  warm-blooded  animals,  it 
represents.  It  also  incloses  and  protects  the 
organ  of  hearing. 

In  cold-blooded  animals  there  is  not  this 
adjustment  of  the  surfaces  of  the  brain  and  its 
.case;  but,  although  in  them  the  parietes  of  the 
cranium  are  expanded  beyond  the  limits  of  the 
brain,*  the  principle  of  formation  is  neverthe- 

*  Thus,  according  to  Desmoulins  the  area  of  a 
vertical  section  of  the  brain  in  the  European  tor- 
toise is  nearly  one-third  less  than  the  area  of  the 
cranial  cavity  ;  and  in  Fishes,  whether  osseous  or 
cartilaginous,  the  disproportion  is  constantly  still 
greater.— ED. 


CRANIUM. 


725 


less  the  same;  and  a  glance  at  the  seveval 
classes  of  vertebrated  animals  will  demonstrate 
that  security  for  the  brain  is  the  grand  aim  of 
the  contrivance,  and  that  the  modification  it 
sustains  in  the  case  of  Fishes  and  Reptiles  is 
for  the  purpose  of  carrying  into  effect  some 
additional  design. 

Considering  the  cranium  as  a  capsule  for  the 
brain,  its  form  is  necessarily  determined  by  the 
extent  to  which  that  organ  is  developed  in  the 
several  classes  of  animals ;  while,  at  the  same 
time,  the  nature  of  its  organization  is  in  harmo- 
nious correspondence  with  their  habits, and  with 
the  external  circumstances  by  which  they  are 
surrounded.  J3y  pursuing  this  inquiry  from  the 
lowest  to  the  highest  animals,  it  will  be  per- 
ceived that,  as  respects  both  form  and  struc- 
ture, additions  are  made  in  proportion  as  the 
endowments  are  of  a  more  and  more  exalted 
character;  and  further,  that  these  successive 
changes  of  structure  are  the  changes  which  the 
human  skull  itself  experiences  in  its  progress 
from  a  foetal  to  an  adult  condition. 

The  rudimentary  part  of  the  most  elaborate 
cranium  is  a  sac  consisting  of  two  membranes 
and  an  intervening  gelatinous  iluid ;  in  the 
next  step  of  the  formative  process,  this  gelati- 
nous fluid  gives  place  to  cartilage.  A  deposi- 
tion of  earthy  matter  in  this  cartilaginous  nidus 
gives  it  firmness,  but  breaks  up  the  sac  into 
isolated  unimited  patches.  These  isolated 
patches  coalesce  in  definite  numbers,  and  thus 
establish  a  secondary  and  less  numerous  divi- 
sion of  ununited  parts;  these,  in  their  turn, 
approach  and  combine  with  each  other,  form- 
ing a  solid  case  of  bone;  and  lastly,  this  solid 
case  resolves  itself  into  two  tables  of  different 
structure,  and  a  still  further  differing  connect- 
ing medium.  In  each  and  all  of  these  states 
through  which  the  crania  of  the  Mammalia 
pass  there  is  presented  to  us  a  type  of  the  skull 
in  some  lower  animal. 

In  Fishes  the  cranium  is  little  more  than  a 
tubular  continuation  of  the  spine  through  the 
head  to  contain  a  similar  prolongation  of  the 
medulla  spinalis.  These,  however,  are  not  in 
contact.  A  mass  of  reticulated  membrane, 
holding  in  its  cells  a  gelatinous  iluid,  forms  the 
real  superior  investment  of  the  brain ;  while 
the  superjacent  parietes  are  designed  to  afford 
an  extensive  origin  to  the  muscles  of  the  body; 
and  as  these  muscles  increase,  so  does  the  sur- 
face of  their  attachment.  For  this  purpose  it  is 
that  the  ossific  deposits  remain  ununited,  that,  by 
being  simply  in  juxtaposition,  or  at  most  over- 
lapping each  other,  they  may  unfold  them- 
selves, and  thereby  admit  of  the  head  being 
at  all  times  in  proportion  to  the  rest  of  the 
body. 

In  Reptiles  the  skull  is  still  further  deve- 
loped. It  is  charged  more  with  earthy  than 
with  animal  matter;  and  this  being  loosely 
distributed,  tough  spongy  bones  are  the  result. 
The  tardiness  of  their  circulation  does  not 
favour  the  combination  of  the  individual  por- 
tions, and  the  bones  are  therefore  for  the  most 
part  loose,  although  some  of  them  unite  by  a 
species  of  anchylosis  in  the  direction  in  which 
defence  is  required.  ^ 


In  Birds  the  character  both  of  form  and 
structure  is  greatly  changed ;  light,  fragile,  and 
compact,  it  is  (by  reason  of  the  high  Mate  of 
vitality  which  prevails)  so  rapidly  and  com- 
pletely ossified  over  its  entire  surface  as  to 
afford  no  evidence,  or  but  a  very  slight  one,  of 
its  original  subdivision.  In  conformity  with 
the  development  of  the  brain,  it  extends  itself 
backwards,  to  each  side,  and  upwards  as  well 
as  forwards,  thus  constituting  a  considerable 
portion  of  the  entire  head. 

In  Mammiferous  animals  the  skull  is  more 
compact  than  that  of  Reptiles  and  more  diffuse 
than  that  of  Birds.  Its  elementary  portions 
unite  so  as  to  form  a  determinate  number  of 
bones  which  are  either  dovetailed  together  by 
the  interlacement  of  crooked  processes  with 
which  their  edges  are  liberally  studded,  or  flow 
into  each  other  so  as  to  exhibit  no  trace  of  their 
junction.  Its  structure  is  made  up  of  two 
osseous  lamella;,  called  an  inner  and  an  outer 
table,  which  are  united  by  an  areolar  ossific 
tissue,  termed  diplo'c,  that  adds  greatly  to  the 
defensive  properties  of  the  skull. 

The  Cranium  (in  human  anatomy)  is  a  hollow 
bone  of  an  ovoid  figure ;  elongated  from  be- 
hind forwards ;  narrower  before  than  behind ; 
compressed  on  the  anterior  part  of  its  sides ; 
surmounting  the  face  and  spine,  and  projecting 
considerably  beyond  the  latter.  It  contains  in  its 
parietes  the  organs  of  hearing,  and  contributes 
to  form  the  orbits,  the  nostrils,  and  the  face. 

The  dome-like  upper  portion  is  termed  the 
calvaria,  and  the  lower  part  is  the  base.  The 
former  presents  the  synciput  in  front,  the  occiput 
behind,  the  vertex  or  brcgma,  (j3p£%/Aa,  from 
@F*x,u>  ir™£°>)  above,  and  the  temples  on  the 
sides. 

Placed  at  the  summit  of  the  body  and  des- 
tined to  contain  the  brain,  the  skull  is  pierced 
at  its  base  by  numerous  foramina  for  the  trans- 
mission, 1st,  of  the  nerves  which  establish  the 
communication  between  the  brain  and  other 
organs ;  and  2dly,  of  the  vessels  which  supply 
the  brain  and  its  membranes. 

From  the  inferior  surface  of  the  cranium,  be- 
tween its  anterior  and  middle  thirds,  there  de- 
scend two  columns  which  limit  posteriorly  the 
boundaries  of  the  face ;  so  that  it  is  anteriorly 
to  these  columns  that  it  contributes  to  form  the 
orbits  and  the  nose,  and  consequently  there  the 
bones  which  enter  into  the  composition  of  the 
face  are  fixed  to  it.  Hence  the  surface  of  that 
part  is  very  irregular,  presenting,  in  addition  to 
the  foramina,  depressions  and  elevations,  sulci 
and  processes  indicative  of  the  articulation  of 
bones  and  the  lodgement  of  other  organs. 
Posteriorly,  between  its  middle  and  posterior 
thirds,  the  base  of  the  cranium  overtops  the 
spine,  and  a  great  opening  there  establishes  the 
continuity  of  the  vertebral  canal  with  the  inte- 
rior of  the  skull ;  and  the  muscles  which  move 
the  head  and  maintain  its  equipoise  being  at- 
tached around,  but  especially  behind  this  open- 
ing, the  skull  iy  strongly  marked  in  that  direc- 
tion. The  intermediate  space  or  middle  third 
is  above  the  pharynx,  offering,  centrally,*  plain 
surface  to  form  the  roof  of  that  cavity,  and, 


726 


CRANIUM. 


laterally,  rough  surfaces  and  processes  for  the 
attachment  of  muscles  concerned  in  deglutition, 
also  some  of  the  foramina  already  referred  to, 
for  the  transmission  of  the  vessels  and  nerves 
of  the  throat  to  and  from  the  interior  of  the 
skull,  as  well  as  the  surfaces  on  which  the 
lower  jaw  moves. 

The  upper  surface  of  the  base  conforming  to 
the  base  of  the  brain,  there  are  larger  depres- 
sions on  it  for  the  anterior  and  middle  lobes;  a 
deep  pit  or  cavity  for  the  cerebellum,  and  in 
the  centrea  broad  sulcus,  which  glides  into  that 
pit,  for  the  medulla  oblongata,  as  well  as  strong 
ridges  and  processes  to  afford  attachment  to  the 
membranous  partitions  which  severally  exist 
between  the  cerebrum  and  cerebellum,  the  he- 
mispheres of  the  former  and  the  lobes  of  the 
latter  organ. 

The  bones  into  which  the  cranium  is  separable 
or  of  which  it  is  immediately  formed,  are  eight, 
viz.  the  sphenoid,  tlnefrontal,  the  ethmoid,  the 
occipital,  the  two  temporal,  and  the  two  parietal. 
The  first  named  bone  is  so  placed  as  to  be  in 
connexion  with  all  the  others,  and  to  have 
them  grouped  around  it ;  so  that  the  frontal 
(F,  Jig.  370)  and  ethmoid  are  in  its  front,  the 


Fig.  370. 


through  the  medium  of  the  posterior  ethmoidal 
cells  into  the  superior  meatus  of  the  nose.  On 
its  upper  surface  is  a  deep  depression  fephip- 
pium,sellaturcica,  fossa  pituitaris)  for  the  lodge- 
ment of  the  pituitary  gland.  The  posterior  bor- 
der of  this  depression  presents  a  crest,  the  corners 
of  which  are  slightly  tumid,  (posterior  ephip- 
pial,  or  c  lino  id  processes,)  for  the  attachment  of 
the  tentorium,  and  this  crest  is  prolonged  down- 
wards and  backwards  under  the  name  of  the 
basilar  process,  to  join  the  process  of  the  same 
name  of  the  occipital  bone;  on  each  side 
there  is  a  depression  (sulcus  caroticus)  for 
the  reception  of  the  internal  carotid  artery, 
and  which  also  marks  the  situation  of  the 
cavernous  sinus.  On  its  under  surface  may 
be  seen,  on  the  median  line,  the  processm 
azygos  (rostrum),  which  is  wedged  into  the 
base  of  the  vomer,  and  on  each  side  of  it  a  line 
indicating  the  articulation  of  the  two  plates  of 
which  the  vomer  is  formed.  Still  more  out- 
wardly there  is  a  groove  which  is  converted  into 
a  canal  by  the  application  against  it  of  the  in- 
ferior orbitary  or  sphenoidal  process  of  the  pala- 
tine bone. 

Fig.  371. 


occipital  (O,  Jig.  372)  is  behind  it,  the  two 
temporal  (T,  Jig.  370)  are  on  its  sides,  and 
the  two  parietal  (P,  Jig.  370)  are  above  it. 

The  sphenoid  bone  (from  crpyjv,  cuneus,  os 
sphenoidale;  Germ.  Sphenoidal-knochen,  Keil- 
knochen)  comprehends  the  quadrilateral  mass 
which  forms  the  centre  of  the  frame-work,  the 
anterior  ribs  which  support  the  frontal  and  partly 
the  lateral  domes,  and  the  depending  pillars 
which  form  the  boundaries  of  the  face ;  it  extends 
to  each  temple,  is  behind  and  in  part  forms  the 
orbits  and  the  nose,  and  is  also  behind  but  in 
close  connexion  with  the  bones  of  the  face. 

The  central  portion  is  called  the  body,  and 
the  diverging  processes  are  named  alae  majores 
and  alae  minores. 

The  body  is  of  a  quadrilateral  figure,  hollow 
and  divided  by  a  partition  into  two  chambers 
(the  sphenoidal  cells,  s,  Jig.  371),  which  open 


The  anterior  surface  exhibits  the  openings  of 
the  sphenoidal  cells,  having,  between  them,  and 
apparently  a  continuation  of  their  septum,  a 
prominent  ridge  which  articulates  with  the  ver- 
tical plate  of  the  ethmoid,  and,  below  them,  the 
triangular  curved  processes  denominated  the 
turbinated  processes  of  the  sphenoid  bone.  Ex- 
ternally to  these  foramina  and  turbinated  pro- 
cesses on  each  side  is  a  rough  line  for  the  arti- 
culation, in  its  two  superior  thirds,  of  the 
orbital  plate  of  the  ethmoid,  and,  in  its  inferior 
third,  of  the  orbitar  process  of  the  palatine  bone. 
To  the  outer  side  of  this  rough  line  is  a  smooth 
surface  which  contributes  to  the  formation  of 
the  orbit. 

The  posterior  surface  is  rough,  quadrilateral, 
and  at  an  early  age  becomes  indissolubly  united 
to  the  basilar  process  of  the  occipital  bone 
(d,  Jig.  371);  for  which  reason  Scemmerring 
and  Meckel  have  regarded  as  one,  the  occi- 
pital and  sphenoid  bones,  and  as  such  have 
described  it  under  the  name  of  os  basilare. 

This  surface  is  bounded  superiorly  by  the 
basilar  process  before  mentioned,  which  is 


CRANIUM. 


727 


placed  with  such  a  degree  of  obliquity,  that  it 
may  be  questioned  whether  it  be  on  the  posterior 
or  superior  surface  of  the  body  of  the  bone.  It 
is  smooth,  slightly  concave,  and  on  its  edges 
may  often  be  seen  the  commencement  of  the 
sulci  basiltires  for  the  lodgement  of  the  basilar 
sinuses. 

The  ala.  majores  are  those  large  curved  pro- 
cesses, which,  stretching  outwards,  forwards, 
and  upwards,  contribute  to  form  the  middle 
fossae  of  the  skull,  the  orbits,  and  the  temples. 
The  upper  surface  of  each  ala,  that  which  in 
part  forms  the  middle  fossa  of  the  base  of  the 
skull,  is  concave  from  side  to  side,  and  still 
more  so  from  behind  forwards.  On  it  are  seen 
(though  not  so  distinctly)  the  digital  impres- 
sions which  mark  the  lodgement  of  convo- 
lutions of  the  brain  on  the  cerebral  surface  of 
the  other  bones  of  the  skull.  Close  to  the  spot 
where  it  departs  from  the  body  of  the  bone 
there  is  a  sulcus  directed  forwards,  and  ter- 
minating in  a  round  hole  (foramen  rotund um) 
for  the  exit  of  the  superior  maxillary  branch 
of  the  par  trigeminum  or  fifth  pair  of  nerves. 
More  outwardly,  and  behind  the  plane  of 
the  posterior  edge  of  the  body  of  the  bone, 
is  a  large  oval  opening  (foramen  ovale),  di- 
rected downwards  and  slightly  outwards  for  the 
transmission  of  the  inferior  maxillary  branch 
of  the  par  trigeminum  and  the  entrance  of  the 
ascending  pharyngeal  artery,  which  then  be- 
comes a  meningeal  vessel.  Behind  this  fora- 
men is  another  (the  foramen  spinale),  which  is 
very  small,  and  affords  entrance  to  the  middle 
meningeal  artery. 

On  the  Inferior  surface  are  seen  the  pterygoid 
processes  descending  from  the  great  wing  where 
it  joins  the  body  of  the  bone,  to  afford  a  resist- 
ing surface  against  which  the  bones  of  the  face 
may  be  grouped.  Anterior  to  these  processes 
is  the  termination  of  the  foramen  rotundum,  the 
opening  of  which  is  directed  somewhat  out- 
wards, and  from  which  there  passes,  outwards 
and  upwards,  a  groove  (sulcus  temporalis)  for 
a  deep  temporal  branch  of  the  superior  maxil- 
lary nerve.  Behind  the  pterygoid  processes, 
and  extending  from  the  base  of  the  internal  to 
the  extremity  of  the  wing,  is  the  sulcus  Eusta- 
c/iianus,  which  lodges  part  of  the  Eustachian 
tube,  and  on  the  outer  side  of  this  sulcus  are 
seen  successively  the  foramen  ovale  and  the 
foramen  spinale.  Immediately  behind  the  lat- 
ter opening,  and  overhanging  the  Eustachian 
tube,  is  the  styloid  process,  to  which  the  inter- 
nal lateral  ligament  of  the  lower  jaw  is  attached. 
On  the  outer  side  of  the  pterygoid  processes  is 
a  plain  surface  forming  part  of  the  zygomatic 
fossa,  and  bounded  externally  by  a  crest,  which 
marks  the  division  between  the  zygomatic  and 
the  temporal  fossae,  and  which  intervenes  be- 
tween the  superior  attachment  of  the  external 
pterygoid  and  the  inferior  attachment  of  the 
temporal  muscles. 

The  pterygoid  processes  consist  of  two 
plates,  with  a  triangular  separation  inferi- 
orly,  and  they  are  called  the  external  and  the 
internal  pterygoid  processes  or  plates.  The 
external  is  broader,  thinner,  and  is  directed 


more  outwardly  than  the  internal ;  its  outer 
surface,  which  also  looks  a  little  forwards, 
gives  attachment  to  the  external  pterygoid,  its 
inner  to  the  internal  pterygoid  muscles.  The 
internal  is  nearly  vertical ;  it  is  pierced  longi- 
tudinally at  its  base  by  the  canalis  Vidianus 
for  the  passage  of  the  vessel  and  nerve  which 
bear  that  name ;  at  its  inferior  extremity  there 
is  a  hook  (the  haynular  process),  which  acts 
as  a  pulley  for  the  tensor  palati  muscle,  the 
attachment  of  which  to  the  outer  side  of  the 
internal  pterygoid  process  is  shewn  by  a  sul- 
cus which  is  most  evident  at  the  base  (fossa 
navicularis) ;  to  its  anterior  edge  is  applied  a 
thin  plate  of  the  palatine  bone,  thus  sepa- 
rating it  from  the  superior  maxillary,  and  to 
its  posterior  edge  is  affixed  the  aponeurotic 
origin  of  the  superior  constrictor  of  the  pha- 
rynx. The  concavity  between  the  two  pro- 
cesses is  the  fossa  pterygoidea  which  is  occu- 
pied by  the  internal  pterygoid  muscle,  and 
the  notch  at  the  lower  part  (the  hiatus  pala- 
tinus)  is  filled  up  by  the  pterygoid  process  of 
the  palatine  bone. 

The  external  surface  of  each  ala  is  continu- 
ous with  the  inferior ;  it  is  concave  from  before 
to  behind,  and  convex  from  above  downwards ; 
it  contributes  to  the  formation  of  the  temporal 
fossa,  and  the  continuation  of  the  sulcus  tem- 
poralis is  evident  at  its  anterior  part  (S,  Jig. 
373). 

The  anterior  surface  forms  the  major  part  of 
the  external  wall  of  the  orbit,  is  oblong,  di- 
rected forwards  and  inwards,  and  is  narrower 
at  its  extremities  than  in  its  middle. 

The  superior  border  of  the  great  wing  sepa- 
rates the  orbital  from  the  cerebral  surface ;  it 
presents  a  sharp  smooth  edge  on  its  inner  half, 
and  a  rough  irregular  surface  on  its  outer  half; 
it  is  convex,  and  its  convexity  is  directed  up- 
wards, forwards,  and  inwards.  The  sharp 
internal  half  concurs  with  the  alae  minores  to 
form  the  sphenoidal  fissure,  which  will  be  de- 
scribed with  those  processes.  The  external 
rough  half  becomes  broader  as  it  passes  out- 
wards, so  as  to  produce  a  triangular  indented 
surface,  the  outer  edge  of  which  is  prolonged 
at  the  expense  of  the  inner  table  in  such  a 
manner  that  it  overlaps  the  frontal  bone  which 
is  affixed  on  it,  and  this  prolongation  is  con- 
tinued without  the  indented  surface,  so  as  to 
grasp  the  anterior  inferior  spinous  process  of 
theparietal  bone. 

The  external  border  is  nearly  the  reverse  of 
the  former.  It  is  concave,  and  looks  outwards 
and  backwards,  and  it  is  articulated  in  its  entire 
extent  to  the  squamous  portion  of  the  temporal 
bone,  by  which  it  is  overlapped  in  its  anterior 
third,  and  receiving  and  supporting  it  in  its 
two  posterior  thirds  ;  the  former  at  the  expense 
of  its  outer  table,  the  latter  at  that  of  the  in- 
ternal. 

The  posterior  border  is  applied  against  the 
outer  side  of  the  petrous  portion  of  the  tem- 
poral bone,  and  extends  from  the  body  of  the 
sphenoid  to  the  posterior  extremity  of  the  ex- 
ternal border.  The  junction  of  these  two  bor- 
ders forms  the  spinous  process,  which  is  received 


728 


CRANIUM. 


into  the  angle  of  the  petrous  and  squamous 
portions  of  the  temporal  bone.  The  laxator 
tympani  muscle  arises  from  this  process,  and 
the  styloid  process  before  described  descends 
from  it.  The  angle  which  exists  where  this 
border  departs  from  the  body,  in  part  forms  the 
foramen  lacerum  anterius,  an  opening  which, 
in  the  recent  skull,  is  closed  by  cartilage. 

The  anterior  border  consists  of  two  portions 
which  join  with  each  other  at  an  angle.  Of 
these  the  upper  is  indented,  separates  the  or- 
bital from  the  temporal  surface,  and  articulates 
with  the  malar  bone.  The  inferior  portion  is 
smooth,  and  forms  with  the  palatine  and  supe- 
rior maxillary  bone,  the  Jissura  lacera  orbitalis 
inferior. 

The  ula  minores  are  on  the  upper  and  an- 
terior part  of  the  body  of  the  bone  ;  they  ex- 
tend outwards  over  the  superior  borders  of  the 
greater  wings,  and,  gradually  tapering,  they  at 
last  end  in  a  point. 

The  upper  surface  of  each  ala  minor  is  smooth, 
and  partly  forms  the  anterior  fossae  of  the  skull. 
The  processus  ethmoidulis    is   a  thin    lamina 
somewhat  triangular  in  form,   prolonged  for- 
wards on  the  median  line  to  articulate  with  the 
cribriform  plate  of  the  ethmoid  bone.     Passing 
backwards  from  this  process,  there  is  a  slightly 
elevated  line  separating  the  depressions  which 
on  each  side  receive  the  olfactory  nerves,  and 
terminated  posteriorly  by  a  tubercle  (processus 
olivaris)    marking    the    decussation    of   the 
optic  nerves,  and  having  upon  it  a  transverse 
depression   for  the  lodgement  of  their  com- 
missure.   This  depression  terminates  on  each 
side  in  the  foramen  opticum  for  the  passage  of 
the  optic  nerve  and  the  ophthalmic  artery,  in 
such  a  manner  that  the  lesser  ala  appears  to  arise 
by  two  roots,  one  above  and  the  other  below 
the  foramen.    From  the  sides  of  the  processus 
ethmoidalis  there  pass  the  two  transverse  spi- 
nous  processes,  being  the  anterior  serrated  mar- 
gins of  the  wings ;  they  are  articulated  to  the 
orbitar  processes  of  the  frontal  bones,    and 
sometimes  join  by  their  extremities  the  great 
wings ;  thereby,  in  such  a  case,  converting  the 
superior  orbital  fissure  into  a  foramen  without 
the  aid  of  the  frontal  bone.     The  posterior 
margins  of  the  alae  minores  are  smooth  and 
less  sharp  than  the  anterior ;    they  are  pro- 
longed backwards  and  inwards,  so  as  to  form 
on  each  side  a  short  and  thick  triangular  pro- 
cess, the  apex  being  directed  backwards,  called 
the  anterior  cp/iippial  (anterior  clinoid)   pro- 
cess, to  which  the  cornua  of  the  lunated  margin 
of  the  tentorium  are  attached. 

The  inferior  surface  of  each  ala  minor  forms 
the  posterior  part  of  the  orbit.  On  it  is  seen 
the  opening  of  the  optic  foramen,  and  under- 
neath it,  between  the  smaller  and  the  greater 
wings,  the  Jissura  lacera  orbitalis  superior. 
This  fissure  is  completed  into  a  foramen  by 
the  articulation  of  the  frontal  bone  to  the 
sphenoid,  when  it  appears  as  an  elongated 
triangular  opening  directed  from  below  up- 
wards and  from  within  outwards.  Thus  is 
formed  the  foramen  lacerum  orbitale  superius, 
which  allows  to  emerge  from  the  skull  the 


tlu'rd,  fourth,  the  ophthalmic  division  of  the 
fifth,  and  the  sixth  pair  of  nerves,  and  to 
enter  from  the  orbit  the  ophthalmic  veins. 

The  articulations  then  of  this  bone  are,  to 
the  ethmoid,  by  the  ethmoidal  process  and 
the  fore  part  of  the  body ;  to  the  frontal,  by  the 
transverse  spinous  processes,  arid  the  summits 
of  the  great  wing;  to  the  parietal,  by  the  tips ; 
to  the  temporal,  by  the  external  and  posterior 
borders,  and  to  the  malar,  by  the  anterior  bor- 
ders of  the  same  wings ;  to  the  occipital,  by  the 
basilar  process ;  to  the  palatine,  by  the  ptery- 
goid  processes  and  adjacent  part  of  the  body ; 
and  to  the  vomer,  by  the  azygos  process. 

The  sphenoid  bone  is  developed  by  nu- 
merous points  of  ossification,  some  of  which 
coalesce  before  the  others  appear ;  and  during 
the  period  ofintra-uterine  life  the  union  of  these 
parts  is  so  rapid,  that,  at  birth,  the  bone  con- 
sists but  of  three  parts,  one  central,  compre- 
hending the  body  and  smaller  wings,  and  two 
lateral,  each  involving  a  great  wing  and  its  cor- 
responding pterygoid  processes. 

So  early  as  the  third  month  there  appear  six 
points^of  ossification,  two  in  the  great  wings, 
two  in  the  internal  pterygoid  processes,  and 
two  in  the  smaller  wings.     During  the  fourth, 
fifth,  and   sixth   months  six  points  are  esta- 
blished  in   the  body,  one   on  each  side  the 
median  line,  afterwards  another  between  these 
and  the  corresponding  greater  wing,  and  ulti- 
mately another  between  the  optic  foramen  and 
those  already  existing.   During  the  sixth  month 
also  a  deposit  appears  between  the  optic  fora- 
men and  the  olivary  process.     In  the  course  of 
the  seventh  month  the  six  points  of  ossification 
in  the  body  run  into  each  other ;    in  the  next 
month  a  coalition  takes  place  between  those 
in  the  pterygoid  processes  and  those  in  the 
greater  wings,  and  shortly  afterwards  a  similar 
union  occurs  between  the  point  in  the  small 
wing  and  that  near  the  optic  foramen.     To- 
wards the  termination  of  the  ninth  month  the 
two  smaller  wings    are    associated    together, 
which   then  become   attached  to  the  already 
formed  body,  and  thus  constitute  at  birth  the 
three  pieces  which  exist  at  that  epoch. 

In  the  early  period  of  extra-uterine  life  these 
three  portions  unite  into  one,  the  great 
wings  acquire  a  more  determined  curvature 
than  they  at  first  possessed,  the  pterygoid  pro- 
cesses lose  their  striated  appearance,  and  ex- 
hibit more  completely  their  fossa;  but  it  is 
not  until  after  the  lapse  of  years  that  the  ab- 
sorbing process,  which,  commencing  in  the 
centre  of  the  body,  developes  the  sinuses,  is 
terminated,  so  that  during  childhood  there  is 
not  only  an  absence  of  these  sinuses,  but  of 
the  openings  leading  from  them  and  of  the  tur- 
binated  processes  which  are  fixed  to  their  front. 
2.  The  frontal  bone  ( os front  is,  corona;;  Germ. 
das  Stirnbein,)  (F,  jig.  370,  373,)  is  situated 
at  the  anterior  part  of  the  cranium,  forming 
part  of  the  vault  and  part  of  the  base,  but 
considerably  more  of  the  former  than  it  does 
of  the  latter.  It  comprises  the  two  anterior 
ovoidal  domes  and  the  anterior  portion  of  the 
longitudinal  curved  rib  of  the  general  frame- 


CRANIUM. 


vrork,  which  will  be  afterwards  more  fully  ex- 
plained. The  convexity  of  these  domes  is  turned 
outwards  and  forwards  in  such  manner  that  the 
circumference  may  abut  against  the  longitu- 
dinal rib  internally  ;  and,  behind  against  the 
anterior  rib  in  the  base  and  a  portion  of  the 
circumference  of  the  lateral  dome  in  the  vault. 
That  portion  which  is  in  the  base  is,  as  it  were, 
pressed  upwards  to  increase  the  space  of  the 
orbit,  but  not  so  much  so  as,  at  first  sight, 
might  appear;  for  on  the  external  surface  of 
the  junction  of  the  two  portions  there  is  an 
extraordinary  development  of  the  bone,  which 
projecting  over  the  face  destroys  the  uniformity 
of  surface  and  causes  the  orbitar  portion  to 
appear  more  elevated  than  it  is  in  reality,  and 
even  to  pass  backwards  at  right  angles  with 
the  other. 

Fig.  372. 


The  external  surface  of  the  frontal  portion 
in  its  upper  two-thirds  is  smooth,  of  an  equa- 
ble convexity  and  directed  backwards;  its 
inferior  third  is  more  vertical,  and  its  convexity 
is  interrupted  by  prominences.  On  the  me- 
dian line  it  exhibits  evidence  of  its  original 
division  into  two  parts,  and  this  generally  by 
a  slight  ridge,  although  in  some  instances  there 
is  a  linear  depression  of  equal  indistinctness. 
This  line  is  terminated  by  \\\Q  nasal  prominence, 
which  has  immediately  above  it  a  smooth  tri- 
angular surface  (glabella),  and  below  it  a 
rough  notch  for  the  articulation  of  the  nasal 
and  superior  maxillary  bones.  From  the 
centre  of  this  notch  there  is  a  projection  (pro- 
cessus  nasalis),  on  the  fore  part  of  which  are 
fixed  the  nasal  bones,  and  to  its  back  part, 
which  is  grooved,  the  ethmoid  bone  is  ap- 
plied. 

On  either  side  of  the  median  line  there  is, 
at  about  the  distance  of  an  inch  where  the 
middle  joins  with  the  lowest  third  of  the  bone, 
t}\e  frontal  eminence  ( eminent ia  front alis,  pro- 
cessus  primi  genii),  which  marks  the  centre 
of  ossification,  and  the  prominence  of  which 
is  inversely  as  to  the  age  of  the  subject.  Be- 
low this  eminence,  bounding  the  glabella,  and 
inclining  downwards  and  inwards  towards  the 
nasal  prominence  (with  which,  in  fact,  it  is 
ultimately  confounded),  is  a  pyramidal  protu- 
berance, varying  very  much  in  distinctness  in 

VOL.  I. 


different  individuals,  (processus  frontalis,) 
more  evident  below  than  above,  and  indicating 
the  situation  of  the  frontal  sinus.  There  is  a 
slight  depression  underneath  and  to  the  outer 
side  of  this  process,  and,  finally,  the  super- 
ciliary  ridge  terminates  the  frontal  portion  of 
the  bone.  This  ridge  is  more  prominent  at  its 
outer  than  at  its  inner  side ;  its  extreme  points 
are  called  external  and  internal  angular  pro- 
cesses, to  tlie  former  of  which  the  malar  bone 
is  articulated,  to  the  latter  the  os  unguis ;  at 
the  junction  of  its  inner  and  middle  thirds 
there  is  a  hole  (foramen  supra  orbitarium), 
or  otherwise  a  notch^  for  the  passage  of  the 
frontal  branch  of  the  ophthalmic  vessels  and 
of  the  ophthalmic  division  of  the  fifth  pair  of 
nerves.  Behind  the  external  angular  process 
there  is  a  depression  (fossa  temporalis)  which 
forms  part  of  the  temporal  fossa ;  a  part  of  the 
temporal  muscle  is  attached  to  it,  and  it  is 
bounded  above  by  a  line  (linea  temporalis) 
which  is  continuous  with  the  outer  margin  of 
the  external  angular  process,  and  to  which  is 
attached  tlie  temporal  aponeurosis, 

Fig.  373. 


The  posterior  or  cerebral  surface  of  the 
frontal  bone  is  concave,  is  marked  by  depres- 
sions which  correspond  with  the  convolutions 
of  the  brain,  and  by  sulci  for  the  lodgement  of 
the  arteries  of  the  dura  mater,  and  is  conti- 
nuous inferiorly  with  the  orbitar  portion ;  cor- 
responding to  the  eminentiae  frontales  there  are 
two  depressions,  and  on  the  median  line  there 
is  a  sulcus  (sulcus  longitudinalis)  for  the  re- 
ception of  the  longitudinal  sinus,  on  the  edges 
of  which  sulcus  may  sometimes  be  seen  the 
fossae  Pacchionii  for  the  glands  of  the  same 
name.  This  sulcus  as  it  descends  is  generally 
replaced  by  a  dense  crest,  which  projects  con- 
siderably into  the  cavity  of  the  cranium ;  to  it 
and  to  the  edges  of  the  sulcus,  the  falx  cerebri 
is  attached  ;  and  at  its  lowest  point  it  is  bifid, 
so  that,  by  its  being  applied  against  a  similar 
bifurcation  of  the  processus  cristatus  of  the 
ethmoid  bone,  it  contributes  to  form  the  fora- 
men caecum. 

3  B 


730 


CRANIUM. 


The  orbitar  portion  by  its  upper  surface 
supports  the  anterior  lobes  of  the  brain,  and 
its  under  surface  forms  the  root  of  the  orbits. 
It  is  divided  into  two  processes  by  a  longitu- 
dinal notch,  which  corresponds  to  the  roof  of 
the  nose. 

The  orbitar  process  of  either  side  is  convex 
in  both  directions  on  its  upper  surface,  and 
the  mammillary  eminences  and  digital  im- 
pressions formed  by  the  intergyral  spaces  and 
convolutions  of  the  brain  are  of  a  decided 
character.  On  its  under  surface  it  is  concave 
and  triangular,  the  base  being  directed  for- 
wards; at  its  anterior  and  outer  part  there  is  a 
fossa  (fossa  lachrymalis)  for  the  lachrymal 
gland,  and  which  is  overhung  by  the  external 
orbitar  process ;  at  its  anterior  and  inner  part, 
near  to  the  internal  orbitar  process,  and  be- 
tween it  and  the  foramen  supra-orbitarium, 
there  is  a  small  pit  (fossa  Irochlearis)  to  which 
is  fixed  the  cartilaginous  pulley  in  which  plays 
the  tendon  of  the  superior  oblique  muscle  of 
the  eye;  at  the  middle  of  its  inner  edge  there 
is  a  notch,  which,  applied  to  a  similar  notch  of 
the  ethmoid  bone,  constitutes  the  foramen 
orbitarium  internum  anticum,  through  which 
pass  the  ethmoidal  twig  of  the  ophthalmic 
branch  of  the  fifth  pair  of  nerves,  and  the  an- 
terior ethmoidal  branch  of  the  ophthalmic 
artery ;  and  a  little  behind  this  there  is  another 
notch,  which  by  a  like  contrivance  forms  a  hole 
(the  foramen  orbitarium  internum  posticum) 
for  the  passage  of  the  posterior  ethmoidal 
branch  of  the  ophthalmic  artery  and  corres- 
ponding vein. 

The  notch  which  is  between  the  orbitar  pro- 
cesses is  the  hiatus  ethmoidalis  (incisura 
ethmoidalis),  and  in  the  cranium  it  is  filled  up 
by  the  cribriform  plate  of  the  ethmoid  bone. 
Its  longitudinal  is  twice  the  length  of  its  trans- 
verse diameter;  anteriorly,  it  is  bounded  by 
the  notch  which,  in  part,  forms  the  foramen 
coecum  and  the  posterior  surface  of  the  nasal 
process ;  posteriorly,  it  is  open ;  and  its  sides 
are  bounded  by  the  commutual  edges  of  the 
orbitar  processes,  the  tables  of  which  are  sepa- 
rated in  such  a  manner  as  to  communicate  with 
the  ethmoidal  cells  and  close  them  at  the 
upper  part,  and  at  the  anterior  part  of  the 
notch  to  communicate  also  with  the  frontal 
sinuses. 

The  frontal  sinus  is  formed  by  the  separation 
of  the  two  tables  of  which  the  bone  is  com- 
posed, and  by  the  absorption  of  the  diploe ; 
they  are  usually  separated  by  a  septum,  and 
they  communicate  on  each  side  with  the  mid- 
dle meatus  of  the  nose  in  the  manner  indi- 
cated above. 

The  posterior  and  upper  border  of  the  bone 
as  far  down  as  the  posterior  extremity  of  the 
inferior  margin  of  the  fossa  temporalis,  is  arti- 
culated to  the  parietal  bones ;  and  it  will  be 
remarked  that  rather  more  than  the  middle 
third  of  it  advances  upon  and  secures  those 
bones  at  the  expense  of  their  outer  table,  while 
the  inferior  portions  of  it  are  in  their  turn 
grasped  by  each  parietal  bone  respectively, 
the  outer  table  of  the  latter  advancing,  at  this 
part,  upon  the  inner  table  of  the  former. 


Behind  the  external  angular  process,  be- 
tween the  temporal  fossa  on  the  one  hand  and 
the  orbitar  process  on  the  other,  there  is  a 
triangular  rough  surface  which  is  implanted  on 
a  similarly-disposed  surface  of  the  great  wing 
of  the  sphenoid  bone.  The  posterior  margin 
of  this  surface  is  in  apposition  with  the  edge 
of  the  thin  extremity  of  the  small  wing  cf  the 
sphenoid,  to  which  also  is  articulated  the  re- 
maining portion  of  the  posterior  border  of  the 
orbitar  process ;  but  with  this  difference,  that, 
while  in  the  former  instance  the  edges  are  plain 
and  simply  applied  to  each  other,  in  the  latter 
the  margins  are  denticulated,  the  sphenoid 
overlapping  the  frontal  so  as  to  render  the 
roof  of  the  orbit  secure. 

Thus  the  frontal  bone  articulates  by  the  pos- 
terior borders  of  its  two  portions,  with  the 
parietal  and  sphenoid ;  by  the  inner  edges  of 
its  orbitar  processes,  with  the  ethmoid  ;  by  its 
nasal  process,  with  the  nasal ;  by  its  internal 
angular  process,  with  the  lachrymal ;  by  the 
surface  between  the  nasal  and  internal  angular 
processes,  with  the  superior  maxillary  ;  and  by 
its  external  angular  process,  with  the  malar 
bones. 

This  bone  in  the  foetus,  and  for  nearly  two 
years  after  birth,  consists  of  two  pieces,  the 
first  deposit  in  each  being  at  the  prominence 
already  indicated.  From  this  point  the  ossific 
matter  radiates,  and  approaching  that  from  the 
opposite  side,  the  two  combine  so  as  to  form 
on  the  median  line  a  suture  which  is  speedily 
effaced.  Nevertheless  it  occasionally  happens 
that  complete  union  does  not  take  place,  and 
then  the  suture  persists  through  life. 

The  ethmoid  bone  (*)9//,oet£ij$,  r,Qp,o<;,  cribrum, 
os ethmoideum;  Germ.Ethmoidal-knochen) com- 
pletes that  portion  of  the  base  of  the  cranium, 
anterior  to  the  sphenoid,  which  is  not  supplied 
by  the  frontal.  It  is  however  devoted  less  to 
the  skull  than  to  the  face,  with  many  of  the 
bones  of  which  it  is  connected ;  and  it  con- 
tributes greatly  to  form  the  nostrils  and  their 
septum,  as  well  as  both  of  the  orbits. 

As  an  element  of  the  cranium  it  is  very 
simple,  being  merely  a  plate  connecting  the 
two  orbitar  processes  of  the  frontal  bone,  and 
having  on  its  median  line  a  ridge,  which  joins 
the  frontal  spine  before,  to  the  body  of  the 
sphenoid  bone  behind.  This  plate  is  the  cri- 
briform plate  or  process ;  it  is  notched  poste- 
riorly where  it  receives  the  ethmoidal  process 
of  the  sphenoid  bone,  the  apex  of  which  pro- 
cess is  applied  to  the  posterior  extremity  of  the 
central  ridge.  Advancing  forwards,  this  ridge 
quickly  springs  upwards  as  a  pyramidal  pro- 
cess (the  crista  gatli,  or  processus  cristatus), 
to  which  the  falx  cerebri  is  attached ;  its  pos- 
terior edge  is  long  and  oblique,  its  anterior  is 
shorter,  more  vertical,  and  it  terminates  in- 
feriorly  in  two  slightly  divergent  plates,  so  as 
to  form  by  their  articulation  with  the  frontal 
bone  iheforamen  coecum.  On  each  side  of  the 
crista  galli,  more  especially  towards  the  fore- 
part, the  cribriform  plate  is  channelled  for  the 
reception  of  the  olfactory  nerves,  and  each 
channel  is  perforated  by  numerous  foramina 
for  the  transmission  of  the  ramifications 


CRANIUM. 


7:u 


)f  the  olfactory  nerves  (foramina  cribrosa). 
These  openings  are  variable  in  their  number, 
and  differ  from  each  other  in  their  size  and 
modes  of  termination;  those  nearest  the  crista 
galli  are  the  largest,  and  of  them  one  or  two 
of  the  anterior  ones  are  very  considerable;  the 
smallest  are  situated  on  the  outer  edge  of  the 
cribriform  plate,  and  both  of  these" sets  are 
the  orifices  of  canals  which  terminate,  the 
former  about  the  root  and  upon  the  sides  of 
the  septum,  the  latter  on  the  outer  wall  of  the 
nose ;  those  which  are  intermediate  and  in  the 
centre  of  the  channel,  are  complete  foramina, 
and  open  on  the  opposite  surface  of  the  plate. 
Immediately  in  front  of  the  inner  set  of  fora- 
mina, there  is,  between  the  crista  galli  and 
cribriform  plate,  a  fissure  which  gives  passage 
to  the  ethmoidal  nerve  and  vessels. 

From  the  under  surface  of  the  cribriform 
plate  and  at  right  angles  with  it,  there  descend, 
on  the  median  line,  the  nasal  lamella,  and, 
on  each  side,  a  cellular  mass  which  partly 
forms  the  outer  wall  of  the  nostril  and  the  inner 
wall  of  the  orbit. 

The  nasal  lamella,  or  vertical  plate,  forms 
the  upper  portion  of  the  septum  narium  ;  it  is 
immediately  underneath  the  crista  galli,  and 
becomes  gradually  thinner  as  it  descends;  its 
anterior  border  is  rough,  thicker  above  than 
below,  and  articulates,  first,  with  the  nasal 
process  of  the  frontal  bone,  and,  secondly, 
with  the  nasal  bones  themselves ;  its  posterior 
border  is  also  rough  and  is  articulated  to  the 
crest  on  the  fore  part  of  the  sphenoid  bone ; 
its  inferior  border  is,  in  its  posterior  half, 
thin  and  inclined  downwards  and  forwards  to 
be  articulated  to  the  vomer,  and,  in  its  anterior 
half,  somewhat  thicker  and  rougher,  and  in- 
clined downwards  and  backwards  to  be  arti- 
culated with  the  triangular  cartilage  of  the 
nose;  its  sides  are  plain,  and  exhibit  sulci  which 
are  continuous  with  the  foramina  that  open  on 
its  root. 

On  each  side  of  this  lamella  and  between  it 
and  the  lateral  masses  there  is  a  space  which 
is  encroached  upon  in  the  middle  more  than  it 
is  above  or  below,  and  a  portion  of  the  cribri- 
form plate  forms  its  roof. 

The  lateral  masses  are  delicate  in  their  struc- 
ture and  complicated  in  their  arrangement. 
Each  consists  of  a  number  of  cells  (cellule 
ethmoidales),  which  are  divided  by  a  partition 
into  an  anterior  and  a  posterior  set,  with  the 
former  of  which  the  frontal  sinus  communi- 
cates, and  with  the  latter  the  sphenoidal.  The 
outer  surface  of  each  lateral  mass  is  compact 
and  smooth,  and  constitutes  the  greater  portion 
of  the  inner  wall  of  the  orbit.  This  is  the 
orbitar  process  or  os  planum,  which  articulates 
above  with  the  frontal  bone,  below  with  the 
superior  maxillary  and  palate  bones,  behind 
with  the  sphenoid,  and  in  front  with  the  la- 
chrymal. On  its  upper  border  are  seen  the 
two  notches  which  assist  the  frontal  in  forming 
the  anterior  and  posterior  orbital  foramina. 
The  inner  surface  of  this  cellular  mass,  that 
which  looks  towards  the  nasal  lamella,  is  ren- 
dered irregular  by  two  curved  processes  (the 
superior  and  middle  iurbinatcd  processes),  of 


which  the  upper  one  is  smaller,  delicate,  re- 
gular in  its  curve,  and  is  seen  only  on  the 
posterior  half  of  the  wall ;  the  other  is  larger, 
more  spongy,  and  extends  the  entire  length  of 
the  wall.  Both  of  them  are  convex  on  the 
side  next  the  cavity  of  the  nostril,  and  concave 
on  that  which  looks  towards  the  cells;  but  the 
inferior  is  also  at  its  lower  edge  again  curled 
in  such  a  manner  as  to  offer  a  convexity  on  both 
of  its  surfaces.  Between  the  two  turbinated  pro- 
cesses there  is  a  triangular  space  (the  superior 
meatus)  the  apex  of  which  is  directed  forwards, 
and  in  which  there  is  an  opening  commu- 
nicating with  the  posterior  ethmoidal  cells. 
Underneath  the  middle  turbinated  process,  and 
bounded  by  its  concavity  on  the  one  hand  and 
the  cells  on  the  other,  is  the  middle  meatus ; 
into  which  open  the  anterior  ethmoidal  cells, 
and  the  tubular  communication  with  the  frontal 
sinus,  called  infundibulum. 

The  connexions  of  this  bone  are,  behind  to 
the  sphenoid ;  in  front  to  the  frontal  and  nasal 
bones;  laterally  by  its  upper  borders  to  the 
orbitar  processes  of  the  frontal,  by  its  under 
borders  to  the  same-named  processes  of  the 
superior  maxillary  and  palate  bones,  and  by 
its  anterior  border  to  the  lachrymal ;  by  the 
under  edge  of  its  middle  vertical  plate  to  the 
vomer  and  triangular  cartilage;  and  by  the 
anterior  extremity  of  the  outer  surface  of  the 
middle  turbinated  process  to  the  inferior  tur- 
binated bone. 

The  ethmoid  is  the  most  tardy  in  its  deve- 
lopment of  all  the  bones  of  the  cranium.  The 
lateral  masses  exhibit  each  of  them  an  ossific 
deposit  about  the  middle  period  of  intra- 
uterine  life,  but  neither  the  cells  nor  turbinated 
processes  are  much  developed  at  birth,  at 
which  time  also  the  central  portion  is  carti- 
laginous. The  ossification  of  this  part  pro- 
ceeds from  above  downwards,  so  that  the 
crista  galli  is  completely  formed  while  the 
lower  part  of  the  nasal  lamella  is  yet  cartila- 
ginous. During  infancy  the  cribriform  plate 
becomes  narrower,  curved,  and  as  it  were 
compressed ;  the  nasal  lamella  advances  for- 
wards; and  the  spaces  between  the  septum 
and  outer  walls  are  considerably  increased. 

The  occipital  bone  (os  occipitis;  Germ.  Occi- 
pital-knochen,  Hinterhaupts-knochcn,)  is  situ- 
ated behind  the  sphenoid,  and  forms  the  pos- 
terior part  of  the  base  of  the  cranium  and  the 
contiguous  projection  of  the  occiput.  Its 
figure  is  that  of  a  lozenge  with  its  anterior 
angle  truncated,  and  is  so  curved  as  to  be 
generally  concave  on  one  surface  and  convex 
on  the  other.  The  inferior  and  anterior  half 
of  it  is  situated  between  the  two  temporal 
bones ;  the  superior  and  posterior  half  is  be- 
tween the  posterior  margins  of  the  two  pa- 
rietal. 

At  its  anterior  part  it  is  pierced  by  a  large 
elliptical  foramen  (the  foramen  magnum), 
through  which  there  pass,  from  the  skull,  the 
medulla  spinalis  and  its  membranes,  the  sinus 
venosus  and  the  spinal  arteries  ;  and,  into  the 
skull,  the  vertebral  arteries,  the  posterior  me- 
ningeal  arteries,  and  the  nervus  accessorius. 

On  the  cerebral  surface  the  internal  crucial 
3  B  2 


732 


CRANIUM. 


spine  divides  it  into  four  fossae,  the  two  supe- 
rior of  which  are  l\\e  fossa  cere.br i  for  the  pos- 
terior lobes  of  the  cerebrum,  the  two  inferior, 
thefosste  cerebelli,  for  the  hemispheres  of  the 
cerebellum ;  the  former  being  marked  by  the 
convolution  of  the  brain,  they  are  not  so  smooth 
as  those  which  lodge  the  cerebellum.  The 
lower  limb  of  the  crucial  spire  is  prominent, 
and  arises  by  a  bifid  root  from  the  margin  of 
the  foramen  magnum ;  the  upper  limb  is 
grooved  for  the  reception  of  the  longitudinal 
sinus,  and  to  its  borders  the  septum  cerebri  is 
attached  ;  this  groove  is  mostly  directed  to  one 
side  or  the  other,  and  generally  to  the  right ; 
to  the  lateral  limbs  the  tentorium  is  fixed,  and 
the  grooves  which  are  on  them  contain  the 
lateral  sinuses.  At  the  point  where  the  trans- 
verse bisects  the  vertical  portion  of  the  crucial 
spine,  it  is  very  prominent,  is  called  the  inter- 
nal occipital  protuberance,  and  marks  the  situ- 
ation of  the  torcular  Herophili. 

In  front  of  the  foramen  magnum,  ascending 
obliquely  towards  the  sphenoid  bone,  and  nar- 
rowing in  its  ascent,  is  the  upper  surface  of 
the  basilar  process,  which  is  concave  from  side 
to  side  for  the  lodgement  of  the  pons  Varolii 
and  medulla  oblongata,  and  exhibits  on  each 
margin  a  depression  (the  sulcus  basilaris)  for 
the  basilar  or  inferior  petrosal  sinus. 

On  either  side  of  the  foramen  magnum  is  a 
groove  which  advances  from  without  inwards, 
and  from  behind  forwards,  and  lodges  the  ter- 
mination of  the  lateral  sinus.  The  anterior 
extremity  of  this  groove  turns  downwards  and 
forms  a  large  notch  (tiie  fossa jvgularis),  which 
is  bounded  on  the  outer  side  by  a  strong  rough 
process  (the  processus  jugularis),  and  on  the 
inner  side  by  a  smooth  oval  eminence  which 
is  situated  between  it  and  the  sulcus  basilaris, 
and  below  which  is  the  orifice  of  the  foramen 
condyloideum  anticum  for  the  passage  of  the 
motor  linguae  nerve. 

The  external  convex  surface,  in  that  part 
which  is  behind  the  foramen  magnum,  is  di- 
vided into  an  inferior  rough,  and  a  superior 
smooth,  triangular  portion.  The  division  be- 
tween the  two  is  marked  by  a  curved  line 
(the  superior  occipital  ridge),  which  abuts  on 
the  petrous  masses  of  the  temporal  bones, 
and  exhibits  in  its  centre  the  tuberose  process, 
or  the  external  occipital  tubercle,  to  which  the 
ligamentum  nuchae  is  attached.  From  the 
ridge  next  to  the  tubercle  the  occipito-frontalis 
and  trapezius  muscles  arise,  and,  still  more 
outwardly,  the  splenius  capitis  and  the  sterno- 
cleido-mastoideus  are  attached.  From  the  tu- 
bercle to  the  foramen  magnum  extends  a 
longitudinal  spine,  which  is  bisected  in  its 
middle  by  a  second  curved  line  (the  inferior 
occipital  ridge),  and  constitutes,  thereby,  the 
external  crucial  spine.  On  each  side  of  the 
spine  and  between  the  two  ridges,  there  is  a 
considerable  rough  depression  for  the  attach- 
ment of  the  complexus,  and,  to  the  outer  side 
of  it,  one  which  is  smoother,  for  the  trachelo- 
mastoideus.  Between  the  inferior  ridge  and 
the  foramen  magnum,  there  are  on  either  side 
of  the  longitudinal  spine,  indications  of  the 
attachment,  in  succession,  of  the  recti  capitis 


postici  minores  et  majores  and  of  the  obliquus 
capitis  superior.  On  the  outer  side  of  this  region 
is  the  sulcus  occipitalis,  which  runs  backwards 
and  upwards  between  the  surfaces  of  attach- 
ment of  the  trachelo-mastoideus  and  the  com- 
plexus, and  is  formed  by  the  occipital  artery. 

Underneath  the  anterior  half  of  the  margin 
of  the  foramen  magnum  are  the  condyloid  pro- 
cesses, two  elongated  articulating  eminences, 
convex  in  both  directions,  wider  in  the  middle 
than  at  either  end,  inclined  from  above  down- 
wards, from  behind  forwards,  and  from  with- 
out inwards,  and  haying  their  internal  edges 
below  the  level  of  the  external.  On  the  inner 
side  of  each  process  is  a  rough  surface  for  the 
attachment  of  the  odontoid  ligament ;  on  the 
outer  side  is  a  ridge  (the  processus  lateralis) 
which  ends  in  the  jugular  process,  and  gives 
insertion  to  the  rectus  capitis  lateralis;  ante- 
riorly is  the  anterior  orifice  of  the  anterior 
condyloid  foramen  ;  and  posteriorly  there  is  a 
depression  in  which  is  sometimes  seen  a  fora- 
men (foramen  condyloideum  posticum)  through 
which  a  vein  of  the  scalp  communicates  with 
the  terminal  portion  of  the  lateral  sinus. 

In  front  of  the  foramen  magnum  is  the 
under  surface  of  the  basilar  process,  which, 
by  reason  of  the  superior  thickness  of  its  an- 
terior extremity,  is  not  so  oblique  as  it  appears 
on  its  upper  surface.  There  is  a  slight  tuber- 
cle on  the  middle  line  to  which  is  fixed  the 
middle  constrictor  of  the  pharynx,  and  behind 
it,  on  both  sides,  a  transverse  line  for  the  su- 
perior constrictor,  between  which  and  the 
foramen  are  depressions  caused  by  the  recti 
capitis  antici  majores  et  minores. 

The  superior  angle  of  this  bone  is  applied 
on  the  junction  of  the  two  parietal,  and  the 
serrated  borders  which  extend  from  it  to  the 
lateral  angles  are  articulated  to  the  posterior 
borders  of  the  same  bones.  The  upper  angle 
itself  arid  more  than  half  of  the  borders  pro- 
ceeding from  it,  overlap  the  parietals,  but  in 
the  remainder  of  their  extent  the  latter  bones 
overlap  the  occipital ;  in  each  case  the  arrange- 
ment being  the  same  as  that  which  exists  be- 
tween the  parietal  and  the  frontal  bones. 

From  the  lateral  angles  to  the  jugular  pro- 
cesses, a  rough  but  not  denticulated  border 
articulates  it  to  the  posterior  border  of  the 
mastoid  portion  of  the  temporal  bone.  Im- 
mediately in  front  of  the  jugular  process  is  the 
fossa  jugularis,  which  forms,  in  common  with 
the  temporal  bone,  the  foramen  jugulare  or 
foramen  lacerum  posticum  in  basi  cranii, 
through  which  emerge  the  jugular  vein,  the 
pneumo-gastric,  glosso-pharyngeal,  and  spinal 
accessory  nerves.  The  rest  of  the  border  from 
the  fossa  jugularis  to  the  anterior  angle  is  in 
apposition  with  the  petrous  portion  of  the 
temporal  bone,  but  the  quantity  of  cartilage 
between  them  is  too  large  to  admit  of  there 
being  any  fixed  articulation  at  this  part. 

The  anterior  angle  itself  is  truncated  and 
presents  a  rough  quadrilateral  surface,  which 
articulates,  and,  indeed,  consolidates  itself,  at 
an  early  period  of  life,  with  the  basilar  process 
and  body  of  the  sphenoid  bone.  This  union 
is  so  complete  and  so  similar  to  the  union 


CRANIUM. 


733 


which  takes  place  beween  the  several  elements 
of  the  bones  of  the  cranium,  that  Soemmering 
and  Meckel  have  described  the  two  as  one 
bone,  under  the  name  of  os  basilare  or  osspheno- 
occipitale. 

The  connexions  of  this  bone  are  few  and 
simple,  being,  in  its  superior  half,  with  the 
pahetals  ;  in  its  inferior  half,  with  the  tem- 
porals;  at  its  anterior  extremity,  with  the 
sphenoid ;  and,  by  its  condyles,  with  the 
atlas. 

At  birth  this  bone  is  separable  into  four  dis- 
tinct portions,  one  being  in  front,  one  behind, 
and  one  on  each  side  of  the  foramen  magnum, 
the  border  of  which  is,  consequently,  not  then 
completed.  The  anterior  and  two  lateral  por- 
tions are  formed  by  the  extension  of  ossific 
matter  from  one  point  of  deposit  in  each ;  but 
that  posterior  to  the  foramen  is  produced  from 
many  points,  in  the  number  of  which  ana- 
tomists are  not  agreed.  The  ossification  com- 
mences in  the  lower  part,  at  some  distance 
from  the  foramen,  by  one  point  on  each  side 
of  the  median  line;  and  before  they  have 
completely  approached  each  other,  two  ana- 
logous deposits  appear  in  the  upper  part,  which 
coalesce  before  the  upper  and  lower  pieces  are 
joined.  This  occurs  during  the  fourth  month, 
at  which  time  the  inferior  and  broad  part  dis- 
plays on  each  side  another  point  of  ossification 
on  a  level  with  the  spot  where  the  process 
first  commenced;  in  the  fifth  month  the  whole 
of  these  are  consolidated  into  one  piece.  It 
often  happens,  however,  that  other  deposits 
are  formed,  especially  in  the  upper  part ;  and 
frequently  they  refuse  to  merge  into  the  others, 
continuing  then  to  be  distinct  through  life  as 
separate  small  bones  having  their  own  serrated 
margins  to  articulate  with  the  adjoining  struc- 
tures. 

The  lateral  pieces  (those  which  comprehend 
the  condyles,  and  lateral  and  jugular  pro- 
cesses) commence  their  formation  about  the 
fourth  month  ;  and  the  anterior  piece  is  the 
last  in  the  order  of  development. 

The  temporal  bone  (os  ternporum;  Germ,  das 
Schlafenbein.)  One  is  situated  on  each  side 
of  the  sphenoid  and  lower  half  of  the  occipital 
bone ;  they  complete  the  base  of  the  cranium 
and  form  the  inferior  part  of  the  sides  of  the 
vault. 

For  the  purposes  of  description  it  is  usually 
divided  into  three  portions;  one,  strong  and 
compact,  in  the  base  and  between  the  middle 
and  posterior  fossae,  the  petrous;  a  second, 
tumid  and  less  dense,  behind  the  ear,  the 
mastoid;  and  a  third  rising  from  the  former 
two,  thin  and  scaly,  situated  in  the  temple, 
the  squamous. 

The  petrous  portion  is  an  elongated,  pyra- 
midal mass,  of  which  two  of  the  surfaces  enter 
into  the  formation  of  the  cavity  of  the  cranium, 
and  the  third  is  underneath.  It  is  situated  on 
a  line  which,  if  prolonged,  would  extend  from 
behind  the  ear  to  the  opposite  external  angular 
process  of  the  frontal  bone;  but  it  is  limited 
by  the  body  of  the  sphenoid.  It  occupies  the 
space  between  the  posterior  border  of  the  ala 
major  of  the  sphenoid  and  the  basilar  process 


of  the  occipital  bone,  in  the  angle  of  which  its 
free  extremity  is  impacted.  In  its  substance 
is  contained  the  labyrinth  of  the  ear. 

Of  the  two  surfaces  which  are  in  the  cra- 
nium, one  is  superior,  the  cerebral;  the  other  is 
posterior,  the  cerebellar, 

On  the  cerebral  surface  near  its  middle,  is  a 
smooth,  convex,  and  transverse  elevation  (the 
processus  semicircularis),  produced  by  the  su- 
perior semicircular  canal  of  the  labyrinth  ; 
immediately  in  front  of  this  is  a  depression  on 
which  the  Glasserian  ganglion  lies  ;  more  out- 
wardly and  running  lengthwise,  is  a  faint 
sulcus  (the  sulcus  Vidianus),  which  terminates 
at  a  small  opening  (the  hiatus  Fallopii)  for  the 
entrance  of  the  Vidian  nerve  into  the  aque- 
ductus  Fallopii. 

On  the  cerebellar  surface  is  seen  thejorarncn 
auditorium  internum,  the  superior  and  posterior 
part  of  the  margin  of  which  is  more  prominent 
than  the  anterior,  which,  in  fact,  degenerates 
into  a  sulcus.  It  is  the  commencement  of  a 
canal  (the  meatus  auditorius  internus)  into 
which  pass  the  acoustic  and  facial  nerves,  and 
the  bottom  of  which  is  divided  by  a  ridge  into 
two  unequal  depressions;  the  upper  one  being 
thejbssula  parva,  in  which  is  the  orifice  of  the 
aqueduct  of  Fallopius  for  the  exit  of  the  facial 
nerve ;  the  lower  one  being  the  fossula  magna, 
in  which  are  several  minute  perforations  for 
the  acoustic  nerve.  Behind  the  foramen  audi- 
torium is  an  indistinct  slit,  which  is  the  ter- 
mination of  the  aqueductus  vestibuli ;  above 
and  rather  anterior  to  this  slit  is  a  triangular 
orifice  for  the  entrance  of  vessels;  and  below  it, 
extending  to  the  foramen  lacerum  posticum, 
is  a  slight  groove. 

Between  the  cerebral  and  cerebellar  surfaces 
there  is  a  sharp  ridge  on  which  there  is  a 
groove  (the  sulcus  petrosus),  more  evident  pos- 
teriorly than  anteriorly ;  to  the  ridge  is  attached 
the  tentorium ;  the  groove  lodges  the  petrosal 
sinus. 

The  under  surface  is  divided  into  two  parts 
by  a  sharp,  prominent  ridge,  which  has  on 
either  side  of  it  a  considerable  fossa.  That  on 
its  outer  side  is  the  fossa  parotidca  for  the 
upper  part  of  the  parotid  gland ;  that  on  its 
inner  side  is  a  thimble-like  depression  (the 
fossa  jugular is) ,  which  forms  with  the  occipital 
bone  the  foramen  lacerum  posterius.  In  this 
bone,  however,  it  is  not  so  wide  as  it  is  in  the 
occipital;  from  which  it  results  that  the  fora- 
men is  imperfectly  divided  into  two  parts — 
the  anterior  for  the  nerves,  the  posterior  for 
the  vein ;  and  it  is  the  latter  organ  which  is 
lodged  in  the  fossa  jugularis  of  the  temporal 
bone.  The  fossa  parotidea  is  limited,  above 
and  in  front,  by  a  fissure  (thejissura  Gtasseri), 
which  penetrates  to  the  tympanum  and  gives 
exit  to  the  chorda  tympani  and  entrance  to 
the  laxator  tympani  muscle;  behind,  by  the 
external  auditory  process.  The  margin  of  the 
foramen  auditorium  externum,  which  is  ellip- 
tical, has  its  long  diameter  vertical,  and  is 
the  commencement  of  the  meatus  auditorius 
externm ;  a  tube  which  is  curved  a  little 
downwards,  is  more  expanded  at  its  extre- 
mities than  in  its  middle,  and  terminates  at 


734 


CRANIUM. 


the  membrana  tympani,  in  front,  by  a  sulcus 
which  is  situated  on  the  border  between  the 
cerebral  and  under  surfaces,  and  passes  back- 
wards, between  the  petrous  and  squaraous 
portions  as  a  canal  (the  canalis  Eustachianus), 
which  is  divided  by  a  lamina  of  bone,  called 
the  processus  cochleariformis,  into  two  parts, 
the  inferior  of  which  contains  the  Eustachian 
tube,  and  the  superior  the  tensor  membranae 
tympani  muscle.  Immediately  behind  the 
fossa  jugularis  there  is  a  rough  surface,  for  the 
articulation  of  the  jugular  process  of  the  occi- 
pital bone ;  and  to  the  outer  side  of  this  sur- 
face is  the  foramen  stylo-mastoideum  for  the 
exit  of  the  facial  nerve.  In  front  of  and  close 
to  this  foramen,  and  between  it  and  the  jugular 
fossa,  is  the  long  pointed  process  (the  styloid 
process)  for  the  attachment  of  the  stylo-maxil- 
lary and  stylo-hyoid  ligaments,  and  the  stylo- 
pharyngeus,  stylo-glossus  and  stylo-hyoideus 
muscles;  this  process  is  embraced  on  the 
outer  side  at  its  root  by  a  portion  of  the  ridge 
separating  the  parotid  and  jugular  fossae;  that 
portion  is  called  the  vaginal  process.  In  front 
of  the  fossa  jugularis  are  two  foramina ;  one 
very  large,  the  foramen  caroticum  ;  the  other 
very  small,  to  the  inner  side  of  the  former  and 
nearly  on  the  margin  between  this  and  the 
cerebellic  surfaces,  being  the  termination  of  the 
aqueduct  of  the  cochlea.  The  foramen  caro- 
ticum is  the  inferior  opening  of  the  canalis 
caroticus,  a  canal  which  exists  in  the  bone, 
and  consists  of  two  parts  that  are  at  right 
angles  with  each  other — the  inferior,  short, 
vertical,  and  extending  upwards  from  the  fo- 
ramen caroticum  into  the  substance  of  the 
bone;  the  superior,  horizontal,  running  length- 
wise, and  extending  to  the  end  of  the  petrous 
process :  in  this  canal  there  pass  the  carotid 
artery  to  the  cavity  of  the  cranium,  and  a 
filament  of  the  nervus  abducens,  as  well  as 
one  of  the  Vidian,  to  the  neck.  A  rough  sur- 
face is  observed  anterior  to  the  foramen  caro- 
ticum for  the  attachment  of  the  levator  palati 
and  the  tensor  tympani  muscles. 

The  outer  and  posterior  extremity  of  the 
petrous  is  confounded  with  the  mastoid  and 
squamous  portions;  the  inner  and  anterior  is 
open,  and  the  bone  is  so  much  removed  at  its 
upper  part  (to  allow  the  carotid  artery  to  pass 
upon  the  body  of  the  sphenoid)  that  it  there 
appears  more  like  a  deep  groove  than  a  tube. 
This  is  filled  up  in  the  recent  subject  by  a 
plate  of  cartilage,  but  in  the  dried  skull,  when 
this  cartilage  has  been  removed,  there  is  found 
an  opening,  between  the  sphenoid  bone  and 
this  extremity  of  the  temporal,  which  is  called 
the  foramen  lacerum  anticum. 

The  mastoid  portion  is  situated  at  the  outer 
end  of  the  petrous,  and  behind  and  below  the 
squamous.  It  is  of  a  nipple-like  shape,  with 
an  upper  horizontal  denticulated  border,  with 
which  the  posterior  inferior  angle  of  the  pari- 
etal bone  articulates ;  and  with  a  posterior  semi- 
circular border  which  is  joined  to  the  occipital : 
in  both  directions  it  is  overlapped  by  the  bones 
to  which  it  is  joined,  except  at  the  lower  part, 
where  it  is  applied  to  the  occipital  by  a  sort 
of  harmonic  suture. 


On  its  inner  surface  there  is  a  deep,  semi- 
circular sulcus  (the  concavity  looking  back- 
wards) which  traverses  its  entire  length  ;  it 
receives  the  lateral  sinus  from  the  parietal  bone 
and  transmits  it  to  the  lower  part  of  the  occi- 
pital :  there  is  generally  observed  in  it  a  fo- 
ramen (the  foramen  mastoideum),  through 
which  a  vein  of  the  scalp  communicates  with 
the  sinus. 

Its  outer  surface  is  roughened  and  gives 
attachment  to  the  sterno-cleido-mastoideus, 
and  sometimes  to  the  trachelo-mastoideus ;  it 
terminates  below  in  the  mammillary  eminence, 
called  the  mastoid  process,  behind  and  to  the 
inner  side  of  which  are  two  grooves — the  one 
nearest  to  the  process  (the  sulcus  digastricus) 
very  evident,  for  the  attachment  of  the  digas- 
tricus ;  the  other  nearly  on  the  articulating  edge 
(sulcus  occipitalis),  less  distinct,  for  the  occi- 
pital artery. 

The  squamous  portion  rises  upwards  from 
the  mastoid,  and  part  of  the  outer  border  of 
the  petrous  portions ;  it  has  a  semicircular  mar- 
gin which  embraces  the  parietal  and  sphenoid 
bones. 

Its  internal  surface,  which  is  concave,  con- 
tributes to  form  the  middle  fossa  of  the  cra- 
nium, and  exhibits  strongly  the  depressions 
and  elevations  which  correspond  to  the  con- 
volutions of  the  brain,  and  to  the  spaces 
between  them.  At  its  anterior  part,  and  com- 
mencing at  the  angle  between  it  and  the  pe- 
trous process,  there  is  a  groove  which  runs 
upwards  and  divides  into  other  grooves,  some 
of  which  pass  backwards;  these  are  formed 
by  the  middle  meningeal  artery  and  its  branches. 
The  external  plate  of  its  border  is  prolonged 
upwards,  in  such  a  manner  that  this  surface  is 
surmounted  by  a  rough  articulating  line,  of 
considerable  breadth,  which  is  applied  on  the 
outside  of  the  parietal  and  partly  on  the  sphe- 
noid bone. 

The  external  surface  is  slightly  convex,  is 
smooth,  and  there  may  be  often  seen  indica- 
tions of  deep  branches  of  the  temporal  artery 
having  passed  over  it.  It  forms  in  part  the 
temporal  fossa,  and  the  temporal  muscle  is 
attached  to  it.  At  its  lower  part,  a  process 
(the  zt/gomatic  process)  passes  transversely 
outwards,  and  is  then  twisted  on  itself  in  a  di- 
rection forwards,  after  the  fashion  of  the  ribs  at 
their  angles ;  so  that  the  surface  of  the  process 
which  would  have  been  superior  becomes 
internal,  and  that  which  would  have  been  in- 
ferior becomes  external.  This  process  has 
two  roots,  an  anterior  or  transverse  and  a  pos- 
terior or  longitudinal.  The  former  is  a  convex 
elongated  eminence,  situated  transversely  and 
in  front  of  a  fossa  (the  fossa  articularis),  in 
which  the  condyle  of  the  lower  jaw  is  placed. 
This  root  is  the  eminent ia  articularis,  on  which 
the  condyle,  with  its  inter-articular  cartilage,  is 
thrown  when  the  jaw  is  depressed.  The  pos- 
terior root  has  itself  two  origins,  which  cir- 
cumscribe the  external  auditory  foramen ; 
and  it  flows  into  and  joins  the  anterior,  just 
when  that  root  is  altering  its  direction.  Be- 
tween the  squamous  process,  and  that  part  of 
the  zygpmatic  process  which  is  between  the 


CRANIUM. 


two  roots,  there  is  a  groove  in  which  pluy 
the  posterior  fibres  of  the  temporal  muscle. 
The  fossa  articularis,  which  is  between  the 
roots,  is  bounded  behind  by  the  Glasserian 
fissure  before  mentioned;  it  forms,  with  the 
adjoining  fossa  parotidea,  the  g/cnoid  cavity. 
The  zygomatic  process  extends  forwards  about 
an  inch  from  its  anterior  root ;  being,  therefore, 
convex  externally  and  concave  internally.  Its 
upper  border  gives  attachment  to  the  temporal 
fascia;  its  inferior  (which  is  about  half  the 
length  of  the  superior)  to  the  masseter  muscle. 
Its  external  surface  is  covered  by  the  integu- 
ment, and  its  internal  forms  the  outer  boun- 
dary of  the  temporal  fossa,  in  which  is  situ- 
ated the  temporal  muscle.  The  extremity  of 
the  zygomatic  process  forms  a  point,  on  account 
of  the  under  margin  being  bevelled  and  den- 
ticulated to  articulate  with  the  malar  bone. 

The  circumference  of  the  squamous  process 
is  sharp,  in  all  that  part  which  is  above  the 
level  of  the  zygomatic  process,  and  denticu- 
lated, at  the  expense  of  its  outer  table,  in  the 
rest  of  its  extent ;  so  that  it  rests  on  the  sphe- 
noid bone. 

The  connexions  of  this  bone  and  the  me- 
chanical effects  which  result  from  its  position, 
will  be  readily  understood.  Its  petrous  por- 
tion being  wedged  between  the  basilar  process 
of  the  occipital  bone,  which  serves  it  as  a 
fulcrum,  and  the  ala  major  of  the  sphenoid, 
which  binds  it  against  that  fulcrum ;  the  in- 
ferior part  of  its  squamous  process  resting  on, 
and  being  sustained  by  the  sphenoid  bone, 
while  its  mastoid  process  is  braced  in  by  the 
posterior  inferior  angle  of  the  parietal,  and  by 
the  occipital  bone — the  fronting  squamous 
margin  will  effectually  resist  the  lateral  thrust 
of  the  parietal ;  the  more  so  that  a  limited 
yielding  movement  is  allowed  at  the  fulcrum. 
The  zygomatic  process  advancing  forwards  to 
the  malar  bone,  will,  with  its  fellow  of  the 
opposite  side,  give  stability  to  the  several 
bones  of  the  face ;  and,  in  common  with  the 
pterygoid  processes  of  the  sphenoid  bone, 
maintain  the  integrity  of  the  various  arches 
which  they  form.  It  is  also  connected  with 
the  lower  jaw. 

This  bone  is  developed  from  six  points  of 
ossification :  viz.  one  for  each  of  the  three 
great  divisions,  and  one  each  for  the  zygomatic 
and  styloid  processes  and  the  auditory  canal. 
At  birth  it  consists  of  four  pieces,  the  squa- 
mous (a),  mastoid  (c),  petrous,  and  an  in- 

Fig.  374. 


complete  bony  ring  (</),  to  which  the  mem- 
brane of  the  tympanum  is  attached.  The 
bony  ring  is  the  first  to  join,  by  its  upper  part, 
the  squamous ;  after  which  it  is  consolidated 
with  the  petrous,  and  then  extends  itself  out- 
wards and  backwards  to  form  the  meat  us 
auditorius  externus,  and  all  the  four  pieces  are 
then  united.  In  infancy  the  bone  sustains 
great  changes;  the  squamous  process  from 
being  straight  becomes  curved  ;  the  zygomatic 
process  recedes  from  the  squamous  and  in- 
creases the  space  between  them ;  the  mastoid 
portion  becomes  more  tumid,  is  developed 
upwards  and  backwards,  and  sends  forth  the 
nipple-like  process  which  gives  to  it  its  name. 
The  eminentia  articularis  and  fossa  articularis 
from  an  oblique  assume  a  transverse  direction, 
and  become,  the  one  more  concave,  the  other 
more  convex.  The  styloid  process,  though 
ossified  in  its  middle,  is  frequently,  to  an  ad- 
vanced age,  connected  with  the  bone  by  carti- 
lage only. 

The  parietal  bone  (as  parietale ;  Germ,  die 
ScheitdbeineoderSeitenbeine}  (ftg.37'2,  373  P) 
constitutes  with  its  fellow  the  greater  portion 
of  the  vault  of  the  skull,  and  forms  with  it  a 
sort  of  bridge,  the  corners  of  which  on  each 
side  are  fixed,  the  one  on  the  great  wing  of 
the  sphenoid,  the  other  on  the  mastoid  process 
of  the  temporal  bone,  the  squamous  process 
of  which  braces  in  the  intervening  space. 

The  external  surface  offers  in  its  centre  a 
prominence  which  marks  the  spot  at  which 
ossification  commenced ;  and  it  marks  also 
the  widest  part  of  the  skull.  Below  this  is  a 
semicircular  line  (the  linen  tcmporalis),  to 
which  are  attached  the  temporal  fascia  and 
muscle ;  still  more  inferiorly  is  a  plane  surface 
occupied  by  the  temporal  muscle;  and  be- 
tween it  and  the  lower  border,  is  a  lunated 
articular  portion  with  converging  striae,  to  be 
applied  against  the  squamous  portion  of  the 
temporal  bone.  Near  the  posterior  part  of  the 
bone  and  a  little  removed  from  its  upper  border 
is  the  foramen  parietale,  for  the  passage  of  a 
vein  to  the  longitudinal  sinus. 

The  inner  surface  exhibits  the  usual  indi- 
cations of  the  convolutions  of  the  brain,  and 
also  arborescent  sulci,  which  mainly  proceed 
from  the  anterior  inferior  angle  of  the  bone, 
and  are  directed  upwards  and  backwards  to 
the  fossa  parictalis,  which  answers  to  the  pa- 
rietal prominence  on  the  outer  surface ;  these 
sulci  lodge  the  branches  of  the  middle  menin- 
geal  artery.  Along  the  upper  border  is  a  de- 
pression, which,  with  a  similarly  disposed  edge 
of  the  other  bone,  forms  a  groove  for  the 
lodgement  of  the  longitudinal  sinus,  and 
hence  is  termed  sulcus  longitudinalis ;  near  to 
it  are  sometimes  seen  small  depressions  (fossa 
Pacchionii)  for  the  granulations  of  the  dura 
mater,  called  glandulae  Pacchionii  externse. 

The  borders  are  of  various  lengths;  the 
superior  is  the  longest,  the  inferior  is  the 
shortest,  and  the  anterior  is  longer  than  the 
posterior.  The  superior  is  united  to  the  same 
border  of  the  opposite  bone  by  the  regular 
interchange  of  serrations  of  the  outer  table  ; 
the  anterior  and  posterior  reverse  the  arrange- 


CRANIUM. 


ment  which  obtains  in  the  frontal  and  occipital 
bones;  that  is,  they  are  overlapped  in  the 
upper  part,  while  in  the  lower  they  overlap 
those  bones  ;  the  inferior  is  sharp,  and  merely 
terminates  the  articular  surface  already  al- 
luded to. 

The  angles  contained  within  these  borders 
are  the  Jrontal  (which  is  nearly  a  right  angle) 
formed  by  the  superior  and  anterior  borders ; 
the  occipital  (more  obtuse)  by  the  superior 
and  posterior  borders ;  the  mastoidal,  truncated 
and  articulated  with  the  mastoid  process  of  the 
temporal  bone;  and  the  spinous  (acute)  re- 
ceived on  the  tip  of  the  great  wing  of  the 
sphenoid,  and  intervening  between  the  tem- 
poral and  frontal  bones.  The  mastoidal  angle 
is,  on  its  inner  surface,  traversed  by  a  sulcus 
(the  sulcus  lateralis)  to  lodge  the  lateral  sinus 
and  to  transmit  it  from  the  occipital  to  the 
temporal  bone.  The  spinous  angle  is  deeply 
grooved  on  its  inner  surface  by  the  sulcus 
spinosus  for  the  middle  meningeal  artery,  or 
the  arteria  spinalis  durae  matris;  this  groove 
has  its  place  frequently  supplied  by  a  canal, 
then  called  canalis  spinosus. 

Its  connexions  are  with  its  fellow  above; 
the  temporal  and  sphenoid  below ;  the  frontal 
before ;  and  the  occipital  behind. 

The  parietal,  like  each  half  of  the  frontal 
bone,  is  developed  from  the  protuberance;  and 
from  this  point  the  ossific  matter  radiates  to- 
wards its  several  borders.  While  this  process 
is  going  on,  the  part  above  and  the  part  below 
the  centre  form  a  considerable  angle  with 
each  other ;  but  this  is  much  effaced  when  the 
edges  have  arrived  at  their  destination,  espe- 
cially when  the  squamous  process  of  the  tem- 
poral quits  its  vertical  for  its  curved  position. 

Articulation  of  the  cranial  bones. —  These 
several  bones  are  locked  together  so  as  to  form 
the  envelope  of  the  brain,  and  the  mode  by 
which  their  secure  adherence  to  each  other  is 
effected,  differs  in  the  summit,  on  the  sides, 
and  in  the  base  of  the  cranium. 

In  the  calvaria  they  are  united  either  by  the 
overlapping  or  by  the  dove-tailing  of  their 
edges,  or  else  by  the  two  modes  combined. 
The  inner  table  does  not  proceed  so  far  as  the 
external,  and  the  latter  being  jagged  with  pro- 
cesses which  have  no  definite  form,  but  which 
are  either  tortuous,  or  narrower  at  their  fixed 
than  at  their  free  extremity,  the  outer  tables 
are  immovably  joined  by  the  fixation  of  the 
processes  of  each  side  into  the  spaces  of  the 
other.  By  this  means  the  inner  tables  of  the 
two  bones  are  brought  nearly  into  contact, 
a  thin  lamina  only  of  cartilage  intervening; 
so  that  on  looking  into  the  vault,  but  little 
more  than  a  plain  line  will  be  noticed.  Here, 
however,  there  is  no  overlapping  of  the  outer 
tables;  but  the  only  instance  of  it  is  in  the 
junction  of  the  two  parietals  on  the  median 
line,  by  which,  in  effect,  they  form  but  one 
bone.  On  the  sides  of  the  skull  there  is  a 
mere  overlapping  of  the  descending  by  the 
ascending  portions,  and  to  accomplish  this, 
and  yet  maintain  uniformity  of  surface,  those 
parts  of  the  outer  tables  which  project  beyond 
the  inner  are  pared  off  or  thinned  in  opposite 


directions.  Tims  the  squamous  processes  of 
the  temporal  bones  and  the  great  wings  of  the 
sphenoid  rise  upwards  from  a  fixed  basis  and 
form  a  wall  which  is  bevelled  off  on  the  inner 
edge  of  its  outer  plate,  so  as  to  receive  the 
parietal  and  frontal  bones,  the  outside  of 
which  sustains  a  corresponding  bevelling,  by 
which  arrangement  they  are  prevented  from 
being  thrust  outwards.  The  articulation  of 
the  anterior  and  the  posterior  with  the  middle 
portion  of  the  calvaria,  is  a  modification  of 
the  two  preceding;  that  is,  the  outer  table  is 
partly  bevelled  and  partly  denticulated.  The 
frontal  and  occipital  bones  are  symmetrical 
and  single,  while  there  are  two  parietal;  and^ 
though  these  are  well  united  by  their  mutual 
interchange  of  denticulation,  they  are  yet  mdre 
firmly  consolidated  by  the  extension  of  the 
frontal  and  occipital  bones  on  the  frontal  and 
occipital  angles  of  the  parietals,  and  on  their 
borders  to  some  distance  from  those  angles ; 
each  symmetrical  bone  thereby  forming  a  spe- 
cies of  cramp  on  the  parietals.  The  edges, 
however,  of  the  outer  tables  are  not  pared  to 
a  sharp  ridge,  but  there  is  left  sufficient  to  be 
fashioned  into  processes  to  maintain  the  secu- 
rity of  the  skull  in  a  longitudinal  direction* 
The  parietals  being  thus  firmly  secured  above 
and  below,  the  intervening  portion  of  their 
edges  is  competent  to  act  as  girders  themselves, 
and,  in  fact,  we  find  that  the  lower  part  of 
their  anterior  and  posterior  borders  overlap  the 
corresponding  portions  of  the  frontal  and  occi- 
pital bones  respectively. 

In  the  base  of  the  cranium  the  bones  are 
placed  in  simple  contact,  and  are  so  disposed 
that  forces,  descending  from  above,  will  neces- 
sarily drive  them  closer  to  each  other.  To 
understand  this  rightly,  we  must  suppose  the 
sphenoid  and  occipital  to  form  (which,  in  fact, 
they  do)  but  one  bone  at  an  early  period  of 
life.  The  temporal  bone  is  placed  alongside 
the  occipital,  in  such  a  way  that  the  petrous 
process  is  wedged  into  the  angle  between  the 
basilar  process  of  the  occipital,  and  the  great 
wing  of  the  sphenoid ;  while  the  latter,  again, 
is  wedged  into  the  angle  between  the  petrous 
and  squamous  processes  of  the  temporal  bone. 
It  has  been  said  that  on  the  upper  surface  of 
the  outer  margin  of  the  great  wing,  rests  the 
lower  part  of  the  squamous  process ;  in  case 
of  force  descending  through  the  parietal  bone 
this  will  be  the  fulcrum,  and  the  lever  (the 
squamous  process)  being  directed  outwards, 
the  mastoid  and  petrous  processes  will  neces- 
sarily be  squeezed  more  forcibly  against  the 
occipital  bone  and  its  basilar  process. 

The  peculiar  appearance  presented  by  the 
articulations  on  the  outer  surface  of  the  cal- 
varia, has  procured  for  them  the  name  of 
sutures,  a  term  which  is  applied  frequently  to 
the  joinings  in  the  base,  although  they  are 
essentially  different  in  appearance  and  in  fact. 
Those  which  are  situated  in  the  calvaria,  and 
to  which  the  name  is  more  suitable,  are  the 
coronal,  lambdoidul,  and  sagittal  sutures. 

The  coronal  suture  extends  between  the  two 
great  wings  of  the  sphenoid  bone  across  the 
upper  part  of  the  skull,  and  connects  the  fron- 


CRANIUM. 


737 


tal  to  the  two  parietal  bones  (fig.  373,  a). 
The  lambdoidal  (o)  consists  of  two  diverging 
lines  formed  by  the  articulation  of  the  posterior 
border  of  the  two  parietals  with  the  superior 
half  of  the  occipital ;  and  extends  from  the 
superior  to  the  lateral  angles  of  that  bone. 
The  sagittal  is  the  line  of  union  between  the 
parietals  themselves,  and  runs  longitudinally 
from  the  superior  part  of  the  lambdoidal  to 
the  centre  of  the  coronal  suture.  On  each  side 
of  the  skull  is  the  squamous  suture  (Jig-  373, 
e) ;  it  has  none  of  the  serrated  characters  of 
the  other  sutures,  but  is  an  arched  line  ex- 
tending from  the  great  wing  of  the  sphenoid 
to  the  mastoid  process  of  the  temporal  bone, 
and  traversing  so  much  of  the  border  of  its 
squamous  process  as  embraces  the  parietal 
bone. 

The  squamous  suture  and  the  lambdoidal 
suture  are  connected  by  a  short  transverse  line 
formed  by  the  articulation  of  the  mastoid  angle 
of  the  parietal  bone  with  the  mastoid  process 
of  the  temporal,  and  which  is  called  addita- 
mcntum  sutura  squamosa  (fig-  373,  g).  From 
the  lateral  angle  of  the  occipital  bone  to  its 
jugular  process,  that  is,  from  the  termination 
of  the  lambdoidal  suture  (where  it  is  joined  by 
the  before-mentioned  supplement  of  the  squa- 
mous suture)  to  the  jugular  foramen,  there  is 
a  line  formed  by  the  posterior  border  of  the 
mastoid  process  and  the  occipital  bone  termed 
additamentum  suturtB  lambdoidalis. 

The  transverse  frontal  suture  (Jig.  373,  a) 
is  situated  transversely,  but  forms  several 
angles  in  its  course.  It  extends  from  one 
external  angular  process  of  the  frontal  bone  to 
the  other;  commencing  at  either  angle,  after 
uniting  that  angle  to  the  malar  bone,  it  enters 
the  orbit,  and  unites  the  frontal  bone  to  the 
great  wing  and  to  the  small  wing  of  the  sphe- 
noid ;  it  then  passes  out  of  the  other  side  of 
the  orbit,  joining  the  same  bone  to  the  eth- 
moid, lachrymal,  nasal  process  of  the  superior 
maxillary  and  nasal  bones  themselves ;  enters 
the  orbit  of  the  opposite  side  and  retires  from 
it,  articulating  the  frontal  to  bones  analogous 
to  those  in  the  other  orbit. 

Other  sutures  are  occasionally  enumerated, 
such  as  the  sphenoidal,  which  entirely  sur- 
rounds the  sphenoid  bone ;  and  the  ethmoidal, 
which  bounds  the  cribriform  plate  of  the  eth- 
moid bone.  Both  of  these,  so  far  as  they 
deserve  the  name  of  sutures,  are  comprehended 
in  the  transverse  frontal  suture. 

The  articulations  of  the  temporal  with  the 
occipital,  sphenoid,  and  parietal  bones  have 
been  designated  as  the  petro-occipilal,  petro- 
sphenoidal,  spheno-temporal,  and  spheno-pari- 
etal  sutures;  but,  with  the  exception  of  the 
last,  (which  is  squamous,  and  truly  a  part  of 
that  suture,)  they  are  not  sutures. 

It  ought  further  to  be  remarked  that,  while 
the  bones  of  the  calvaria  are  much  thinner 
than  those  of  the  base,  they  are  comparatively 
thicker  in  their  borders  to  allow  of  that  serra- 
tion from  which  the  term  suture  is  derived. 

To  study,  in  combination  with  each  other, 
the  facts  enumerated  in  the  foregoing  descrip- 
tion, it  is  necessary  to  take  a  survey  of  the 


external    and   internal   surfaces   of  the  skull 
itself. 

For  this  purpose  the  external  surface  may 
be  divided  into  four  regions  :  the  superior,  the 
inferior,  and  the  two  lateral. 

The  superior  region  extends  from  the  nasal 
process  of  the  frontal  bone  to  the  occipital 
protuberance,  and  is  bounded  on  each  side 
by  the  linea  temporalis;  a  curved  line,  which, 
commencing  at  the  external  angular  process 
of  the  frontal  bone,  passes  backwards,  traverses 
the  parietal  below  its  protuberance,  and  is  re- 
ceived on  the  extreme  point  of  the  root  of  the 
zygomatic  process  of  the  temporal  bone.  To 
proceed  from  before  to  behind,  there  are,  on 
the  median  line,  the  nasal  process  and  the 
rough  notch  for  the  articulation  of  the  nasal 
bones;  the  nasal  protuberance;  the  glabella 
bounded  laterally  by  the  frontal  processes;  the 
line  indicating  the  junction  of  the  two  foetal 
portions  of  the  frontal  bone ;  the  centre  of  the 
coronal  suture;  the  whole  length  of  the  sa- 
gittal suture,  with  the  foramen  parietale  on 
each  side  of  it;  the  superior  angle  of  the 
occipital  bone ;  a  part  of  the  occipital  bone 
itself;  and,  lastly,  the  occipital  protuberance. 
Laterally,  and  on  each  side,  there  are  the 
frontal  process,  the  superciliary  ridge,  the 
depression  between  them,  and  the  supra-or- 
bitary  foramen  ;  the  frontal  protuberance  ;  the 
coronal  suture ;  the  parietal  protuberance ;  the 
lambdoidal  suture ;  and  so  much  of  the  side 
of  the  occipital  bone  as  is  above  the  transverse 
ridge. 

The  inferior  region  extends  from  the  pos- 
terior part  of  the  nasal  process  to  the  occipital 
protuberance,  and  is  circumscribed  by  a  line, 
continuous  with  the  extremities  of  the  supe- 
rior curved  ridge  of  the  occipital  bone,  and 
passing  on  the  outside  of  the  mastoid  and  in 
the  direction  of  the  zygomatic  process  of  the 
temporal  bone,  to  the  crest  which  is  on  the 
temporal  process  of  the  great  wing  of  the  sphe- 
noid. The  facts  to  be  here  noticed  are  nu- 
merous, and,  to  facilitate  their  enumeration, 
this  region  may  be  divided  into  three  parts, 
one  anterior  to  the  pterygoid  processes  of  the 
sphenoid  bone,  one  posterior  to  the  articu- 
lating processes  of  the  occipital  bone,  and  a 
middle  one  between  these  two. 

The  anterior  division  contributes  to  form  the 
nose  and  the  orbits.  For  the  first,  there  may 
be  observed  on  the  median  line,  the  nasal 
lamella  of  the  ethmoid  bone,  articulated,  in 
front,  to  the  nasal  process  of  the  frontal,  and, 
behind,  to  the  crest  in  front  of  the  body  of  the 
sphenoid.  On  the  same  line,  but  below  and 
behind  this,  is  the  azygos  process,  and  inferior 
part  of  the  body  of  the  sphenoid,  with  the 
channels  to  form,  with  the  vomer,  the  palatine 
canals.  On  either  side  of  the  nasal  lamella  is 
the  slit  for  the  ethmoidal  nerve  and  vessels ; 
the  cribriform  plate  and  its  foramina ;  and  the 
space  which  assists  to  form  the  nares.  More 
laterally,  and  still  passing  from  before  back- 
wards, is  the  internal  angular  process  of  the 
frontal  bone,  to  unite  with  the  lachrymal  ;  the 
cellular  mass  of  the  ethmoid,  with  its  turbi- 
nated  processes  on  one  of  its  sides,  and  the 


738 


CRANIUM. 


orbitar  plate  on  the  other ;  the  junction  of  this 
mass  to  the  body  of  the  sphenoid ;  the  turbi- 
nated  process  of  the  same  bone,  and,  some- 
times, the  opening  into  its  sinus ;  the  articular 
surface  for  the  palate  bone;  and,  lastly,  the 
base  of  the  pterygoid  process  exhibiting  the 
anterior  orifice  of  the  Vidian  canal. 

Still  more  outwardly  is  the  part  which  forms 
the  orbit,  concave,  and  broader  before  than 
behind.  To  the  fore  part  there  are,  on  the 
outer  side,  the  lachrymal  fossa ;  on  the  inner 
side  the  trochlear  fossa,  and,  near  to  it,  the 
orbitar  orifice  of  the  supra-orbitary  foramen. 
Further  back  there  is  on  the  inner  side  a  por- 
tion of  the  transverse  suture  between  the 
frontal  and  ethmoidal  bones,  containing  the 
two  internal  orbitar  foramina ;  and,  to  the 
outer  side,  another  portion  of  the  same  suture 
between  the  frontal  and  sphenoid.  A  third, 
shorter  portion  connects  the  two  preceding, 
and  unites  the  frontal  to  the  small  wing  of  the 
sphenoid.  Behind  this  there  are  in  succession 
the  foramen  opticum ;  the  foramen  lacerum 
orbitale  superius ;  the  foramen  rotundum ; 
and,  lastly,  the  sulcus  temporalis  leading  from 
the  last  foramen,  and  being  behind  the  orbitar 
process  of  the  sphenoid  bone. 

The  middle  division  offers  in  its  centre  the 
basilar  process  of  the  occipital  bone,  and  the 
line  of  its  junction  with  the  sphenoid.  On  it 
are  seen  the  indications  of  the  attachment  of 
the  pharyngeal  and  anterior  recti  muscles. 
Its  posterior  edge  forms  a  segment  of  a  circle 
to  assist  in  forming  the  foramen  magnum. 
On  either  side,  and  from  before  backwards, 
are  the  external  and  internal  pterygoid  pro- 
cesses, with  the  fossa  navicularis,  fossa  ptery- 
goidea,  and  hiatus  palatinus  between  the  two 
processes;  the  posterior  orifice  of  the  Vidian 
canal ;  the  foramen  lacerum  anterius ;  the 
under  surface  of  the  petrous  process  of  the 
temporal  bone,  with,  on  one  side,  the  line  of 
its  junction  with  the  basilar  process,  and,  on 
the  other,  the  line  of  its  junction  with  the 
sphenoid  bone,  the  Eustachian  sulcus  occu- 
pying the  latter ;  behind  the  foramen  lacerum 
anterius  is  the  rough  surface  for  the  origin  of 
the  levator  palati  and  tensor  tympani  muscles; 
the  inferior  orifice  of  the  carotid  canal ;  the 
opening  of  the  aqueduct  of  the  cochlea ;  and, 
lastly,  the  foramen  lacerum  posterius.  More 
outwardly,  and  pursuing  the  same  direction, 
are  the  under  surface  of  the  great  wing  of  the 
sphenoid  bone;  its  line  of  union  with  the 
temporal ;  the  processus  articularis ;  the  fossa 
articularis ;  the  Glasserian  fissure ;  the  fossa 
parotidea ;  and,  lastly,  the  rough  inferior  bor- 
der of  the  foramen  auditorium  externum.  On 
the  inner  edge  of  this  plane,  and  to  the  outer 
side  of  the  sulcus  Eustachianus,  there  are, 
successively,  the  foramen  ovale ;  the  foramen 
spinale ;  the  styloid  process ;  the  spinous  pro- 
cess, which  is  wedged  into  the  Glasserian  fis- 
sure; the  crest  between  the  fossa  parotidea 
and  the  foramen  lacerum  posterius ;  the  vagi- 
nal process  and  the  styloid  process. 

The  posterior  division  exhibits,  on  the  me- 
dian line,  the  foramen  magnum ;  the  longi- 
tudinal spine  bisecting  the  inferior  curved 


ridge,  and  having,  on  each  side,  below  that 
ridge,  rough  depressions  for  the  attachment 
of  the  posterior  recti  muscles,  and  above  that 
ridge,  still  stronger  and  larger  marks  of  the 
attachment  of  the  complexus  ;  and,  lastly,  the 
inferior  aspect  of  the  occipital  protuberance. 
To  the  extreme  outside  and  passing  from  behind 
forwards,  there  are  the  termination  of  the 
superior  occipital  ridge;  the  additamentum 
suturae  lambdoidalis ;  the  posterior  part  of  the 
mastoid  portion  of  the  temporal  bone  dis- 
playing the  foramen  mastoideum ;  the  sulcus 
occipitalis  on  one  hand,  the  mammillary  pro- 
cess of  the  mastoid  portion  of  the  temporal 
bone  on  the  other,  and  the  sulcus  digastricus 
between  the  two;  and,  lastly,  the  foramen 
stylo-mastoideum  at  the  bottom  of  the  sulcus 
digastricus.  Midway,  and  between  the  me- 
dian and  outer  portions  of  this  region,  and  still 
passing  from  behind  forwards,  there  are,  the 
superior  occipital  ridge,  the  inferior  occipital 
ridge,  and  between  them  the  marks  of  the 
attachment  of  the  splenius  capitis  and  trachelo- 
mastoideus;  the  oblique  surface  into  which 
the  obliquus  capitis  superior  is  inserted ;  the 
posterior  condyloid  fossa,  containing  the  pos- 
terior condyloid  foramen  whenever  it  exists ; 
the  condyle  itself;  the  anterior  condyloid  fossa 
and  foramen ;  and,  lastly,  to  the  outside  of  the 
condyle,  the  processus  lateralis. 

The  lateral  region  (fg.  373)  is  oval,  and  its 
boundaries  have  already  been  stated.  Its  sur- 
face, lengthwise,  is  undulated,  being  convex 
behind,  where  the  temporal  and  parietal  form  it; 
and  concave  in  front,  where  the  temporal  and 
sphenoidal  enter  into  its  composition.  Pro- 
ceeding from  above  downwards,  and  com- 
mencing with  the  linea  temporalis,  we  have 
so  much  of  the  parietal  and  frontal  bones  as 
are  below  that  line,  with  the  inferior  extremity 
of  the  coronal  suture  between  them;  next, 
the  sutura  squamosa  between  the  parietal  and 
temporal  bones,  and  part  of  the  transverse 
suture  between  the  frontal  and  sphenoid ; 
below  tli is,  the  squamous  process  of  the  tem- 
poral bone,  and,  in  front  of  it,  the  temporal 
process  of  the  sphenoid  with  the  line  of  arti- 
culation between  them.  These  parts  form  the 
fossa  temporalis,  which  is  limited  inferiorly, 
on  the  sphenoid  by  a  crest  which  divides  it 
from  the  jugal  fossa  belonging  to  the  face,  and 
on  the  temporal  by  a  groove  on  the  upper  part 
of  the  two  roots  of  the  zygomatic  process,  in 
which  play  the  posterior  horizontal  fibres  of 
the  temporal  muscle.  Passing  from  behind 
forwards,  there  will  be  observed  at  the  lower 
boundary  of  this  region,  the  additamentum 
suturae  squamosse ;  the  base  of  the  mastoid 
process;  the  foramen  auditorium  externum; 
and,  lastly,  the  zygomatic  process  of  the  tem- 
poral bone  articulating  anteriorly  with  the 
malar  bone. 

The  interior  of  the  cranium  presents  through- 
out its  entire  extent  more  or  less  evidence  of 
the  adaptation  of  its  surface  to  the  convolutions 
of  the  brain. 

The  base  is  bounded,  in  front  by  the  fora- 
men coecum  ;  behind,  by  the  centre  of  the 
internal  crucial  spine;  and,  in  its  circumfe- 


CRANIUM. 


739 


rence,  by  a  line  passing  on  each  side  along 
the  outer  border  of  the  orbitar  process  of  the 
frontal  bone,  the  junction  of  the  parietal  and 
sphenoid;  the  parietal  and  temporal  bones;  and 
the  lateral  limb  of  the  internal  crucial  spine  of 
the  occipital. 

It  is  placed  obliquely  downwards  and  back- 
wards, and  consists  of  three  principal  divisions 
or  platforms — the  posterior  being  the  lowest, 
the  anterior  the  highest ;  and  the  middle,  on  a 
plane  between  the  two. 

The  anterior  division  is  called  the  anterior 
fossff,  and  sustains  the  anterior  lobes  of  the 
brain.  It  is  concave  in  the  middle  and  con- 
vex on  each  side ;  it  is  limited,  anteriorly  by 
the  merging  of  the  orbitar  processes  into  the 
general  mass  of  the  frontal  bone,  and  poste- 
riorly by  the  posterior  margin  of  the  alae  mi- 
nores.  On  the  median  line,  from  before  back- 
wards, we  encounter  the  foramen  ccecum ;  the 
crista  galli;  the  ethmoidal  process  of  the 
sphenoid  bone ;  and,  lastly,  the  smooth  sur- 
face of  that  bone  on  which  the  olfactory  nerves 
repose.  On  either  side  of  the  crista  galli  is 
the  processus  cribrosus,  with  its  foramina,  and 
slit  for  the  ethmoidal  nerve  and  vessels  ;  more 
outwardly,  is  the  transverse  suture  uniting  this 
process  to  the  frontal  bone,  and  in  it  may  be 
seen  the  internal  orifice  of  the  anterior  internal 
orbitar  foramen.  From  hence  outwards,  is  the 
orbitar  process  of  the  frontal  bone,  somewhat 
arched,  and  displaying,  more  evidently  than 
in  the  rest  of  the  skull,  the  digital  impressions 
of  the  brain ;  behind  this  is  the  transverse 
suture  uniting  it  to  the  small  wings  of  the 
sphenoid  bone ;  and,  lastly,  there  is  the  upper 
surface  of  the  small  wings  themselves. 

The  middle  fossa  consist  of  two  large  fossae 
laterally,  and  one,  which  is  smaller,  centrally. 
This  latter  is  the  pituitary  fossa;  in  its  front 
is  the  olivary,  and,  behind  it,  is  the  basilar 
process ;  on  its  sides  are  the  sulci  carotici,  and 
its  corners  are  bounded  by  the  ephippial  or 
clinoid  processes.  In  front  of  the  olivary 
process  is  the  groove  on  which  the  optic  nerves 
decussate;  and  between  it  and  the  anterior 
ephippial  processes  of  each  side  is  the  foramen 
opticum. 

The  lateral  fossae  are  very  deep  and  of  an 
irregular  triangular  figure,  the  base  of  which 
is  directed  outwards.  Anteriorly  they  are 
bounded  by  the  small  wings  of  the  sphenoid 
bone,  and  posteriorly  by  the  ridge  which  se- 
parates the  cerebral  from  the  cerebellar  surface 
of  the  petrous  portion  of  the  temporal  bone. 
Each  is  formed,  anteriorly  and  internally,  by 
the  great  wing  of  the  sphenoid  ;  posteriorly, 
by  the  cerebral  surface  of  the  petrous  process ; 
and,  externally,  by  the  squamous  process  of 
the  temporal  bone.  In  it  are  seen  the  lines  of 
junction  between  these  parts,  and  the  sulci 
formed  by  the  spinous  artery  of  the  dura  rnater. 
At  its  anterior  boundary  there  is  the  foramen 
lacerum  orbitale  superius;  and  behind  it, 
inclining  gradually  outwards,  there  are  in  suc- 
cession, the  foramen  rotundum,  the  foramen 
ovale,  the  foramen  spinale,  the  sulcus  Vidi- 
anus,  the  hiatus  Fallopii,  the  depression  for 


the  Glasserian  ganglion,  and  the  processus  semi- 
circularis.  To  the  inner  side  of  this  range, 
and  on  a  level  with  the  foramen  ovale,  is  the 
foramen  lacerum  anterius. 

The  posterior  division  extends  from  the 
basilar  process  of  the  sphenoid  bone  to  the 
internal  tubercle  of  the  occiput.  Its  margin 
is  of  a  triangular  figure,  with  its  base  curved 
and  directed  backwards.  The  petrosal  ridges 
form  the  sides  of  the  triangle,  and  the  lateral 
limbs  of  the  internal  crucial  spine,  its  base. 
On  the  median  line  and  passing  backwards 
we  observe  the  superior  sulcated  surface  of  the 
basilar  process,  with  a  groove  on  each  side  for 
the  basilar  sinus ;  the  foramen  magnum  with 
the  anterior  condyloid  foramina  near  its  ante- 
rior part ;  and,  lastly,  the  inferior  limb  of  the 
internal  crucial  spine,  separating  the  two 
great  cerebellar  fossae.  Each  of  the  latter  is 
bounded,  above  and  to  the  outside,  by  a 
broad  groove  for  the  lateral  sinus,  which 
groove  passes  from  the  occipital  bone  to  the 
mastoid  angle  of  the  parietal,  from  thence  to 
the  mastoid  process  of  the  temporal  (where 
the  mastoid  foramen  opens  into  it),  and,  ulti- 
mately, to  the  occipital  bone  again,  where  it 
turns  forwards  to  the  foramen  lacerum  pos- 
terius.  In  this  groove  is  seen  the  termination  of 
the  lambdoidal  suture,  and  the  additamentum 
suturae  squamosae  and  the  additamentum  su- 
turae  lambdoidalis  cross  it;  the  principal 
portion  of  the  latter  being  seen  in  the  cere- 
bellar fossa.  Anteriorly,  and  above  the  fora- 
men lacerum  posterius,  is  the  cerebellar  surface 
of  the  petrous  process  of  the  temporal  bone ; 
exhibiting  the  openings  of  the  meatus  audi- 
torius  internus  and  of  the  aqueduct  of  the 
vestibule ;  and,  on  the  ridge  which  separates 
this  from  the  cerebral  surface,  the  groove  for 
the  petrosal  sinus. 

The  calvaria  possesses  in  its  centre  a  dense 
curved  rib,  which  extends  through  the  roof 
from  the  anterior  to  the  posterior  part  of  the 
base,  but  which  is  more  evident  at  its  extre- 
mities than  in  its  middle,  where  it  is  generally 
marked  by  a  groove  for  the  longitudinal  sinus. 
The  frontal  spine  commences  it,  and  its  ter- 
mination is  the  superior  limb  of  the  internal 
crucial  spine ;  the  intermediate  portion  (where 
it  is  masked)  is  the  sagittal  suture.  On  each 
side,  and  from  before  backwards,  we  notice 
in  succession  the  frontal  depression ;  the  coro- 
nal suture ;  the  parietal  depression,  and  several 
arterial  sulci  running  towards  it  from  below ; 
part  of  the  lambdoidal  suture;  and,  lastly, 
the  cerebral  fossa  of  the  occipital  bone.  On 
each  side  of  the  sagittal  suture  are  the  fossae 
Pacchioni,  and,  near  its  back  part,  the  foramen 
parietale. 

A  comparison  of  the  external  and  internal 
surfaces  of  the  cranium  establishes  the  fact 
that  there  is  a  general  correspondence  of  the 
two  as  far  as  regards  those  parts  which  are  in 
contact  with  the  periphery  of  the  brain.  But, 
between  the  several  divisions  of  that  organ, 
there  are  developed  on  the  inside  of  the  skull 
very  large  ribs  and  processes  which  destroy  the 
particular  correspondence  of  the  two  surfaces. 


740 


CRANIUM. 


Nevertheless,  this  does  not  impair  our  ability 
to  deduce  the  internal  capacity  of  the  cranium 
from  an  examination  of  its  exterior ;  since  the 
diplb'e  between  the  two  plates,  in  the  spaces 
intermediate  to  these  ribs,  seldom  varies  more 
than  one  or  two  lines  in  its  thickness. 

In  a  skull  of  ordinary  capacity,  the  length, 
measuring  from  the  frontal  spine  to  the  longi- 
tudinal sulcus,  is  five  inches  and  a  half;  ks 
width,  between  the  bases  of  the  petrous  pro- 
cesses of  the  temporal .  bones,  four  inches  and 
a  half;  between  the  parietal  fossae,  five  inches ; 
and  between  the  extremities  of  the  alae  mi- 
nores,  three  inches  and  three  quarters :  its 
depth,  from  the  foramen  magnum,  four  inches 
and  a  half,  from  the  ephippium  three  inches 
and  a  quarter;  and,  from  the  front  of  the 
olivary  process,  two  inches  and  three  quarters. 
But  observation  proves  to  us  that  there  is  little 
dependence  to  be  placed  on  these  measure- 
ments ;  scarcely  any  two  skulls  agree  in  their 
diameters,  for  where  one  exceeds  in  a  given 
direction,  it  may  fall  short  in  some  other.  To 
this  conclusion  we  shall  be  led  by  the  ex- 
amination of  skulls,  not  only  of  members  of 
the  same  community  but  even  of  persons  con- 
nected by  the  closest  ties  of  consanguinity. 
While,  however,  there  is  any  doubt  about  the 
matter,  it  is  not  to  mixed  communities  we 
should  have  recourse  in  our  search  for  facts ; 
but  rather  to  the  well-authenticated  skulls  of 
such  tribes  as  inhabit  parts  of  the  globe  re- 
mote from  each  other,  and  whose  manners  and 
customs  have,  to  the  best  of  our  belief,  re- 
mained stationary  from  time  immemorial ;  for 
by  this  procedure  we  shall  avoid  the  confusion 
arising  from  a  mixture  of  different  races  of 
men  whose  respective  dispositions  have  been 
modified  by  intermarriage. 

The  skulls  of  a  North  American  Indian  and 
a  Hindoo  will  be  good  examples  to  shew  how 
the  diameters  will  vary.  By  making  a  longi- 
tudinal section  of  each,  we  shall  find,  by  ap- 
plying a  line  between  a  spot  about  five-eighths 
of  an  inch  above  the  root  of  the  nose,  and 
another  about  three-eighths  of  an  inch  above 
the  superior  angle  of  the  occipital  bone,  that 
there  is  considerably  more  space  above  the  line 
in  the  Hindoo  than  there  is  in  the  American 
Indian,  while  the  distance  to  the  foramen 
magnum  is  much  greater  in  the  latter  than  in 
the  former.  Again,  if  we  make  the  usual  ho- 
rizontal section,  it  will  be  manifest  that  in 
breadth  the  Indian  will  exceed  the  Hindoo 
by  nearly,  and,  sometimes,  more  than  an  inch, 
although  the  latter  has  the  advantage  in  length. 
In  the  Negro,  which,  in  length,  is  equal  to 
the  Hindoo,  the  space  above  the  line  in  a 
vertical  section  is  not  absolutely,  much  less 
relatively,  so  great  towards  the  frontal  bone 
as  in  the  shorter  skull  of  the  Indian;  while 
towards  the  posterior  part  of  the  parietal s  it  is 
much  greater,  and  in  its  breadth  it  falls  but 
little  short  of  it. 

These  three  aboriginal  types  will  suffice  to 
shew  the  endless  varieties  which  must  prevail 
in  mixed  communities,  and  to  satisfy  us  that 
the  forms  of  skulls  are  as  numerous  as  the 


diversified    modifications    of    character    with 
which  the  Creator  has  endowed  the  human  race. 

Several  naturalists  have  sought  to  establish 
an  analogy  between  the  cranium  and  the  ver- 
tebrae, and  have  imagined  that  they  had  dis- 
covered in  the  one  a  type  of  the  other;  in 
other  words,  that  the  cranium  is  neither  more 
nor  less  than  a  gigantic  vertebra  which  has  been 
submitted  to  some  necessary  modifications. 

In  this  sense  the  ephippium  and  basilar  por- 
tion of  the  occipital  bone  represent  the  body 
of  a  vertebra;  the  foramen  magnum,  the  ver- 
tebral foramen ;  the  longitudinal  spine  of  the 
occipital  bone,  the  spinous  process;  the  ex- 
panded portion  of  the  bone  as  far  as  the  mas- 
toid  portion  of  the  temporals,  the  vertebral 
plates  ;  the  mastoid  processes  themselves,  the 
transverse  processes ;  the  eminence  above  the 
anterior  condyloid  foramina  and  the  condyles 
themselves,  the  superior  and  inferior  oblique 
processes ;  and  the  notch  behind  the  condyles 
and  the  jugular  notch,  the  notches  which  form 
the  conjugal  foramina.* 

Others  again  regard  the  cranium  as  com- 
posed of  several  vertebrae  more  or  less  com- 
plete, which  are  so  associated  as  to  meet  the 
exigencies  of  the  highly  developed  summit  of 
the  medulla  spinalis.  The  resemblance,  how- 
ever, of  many  of  the  parts  to  a  vertebra  is  so 
imperfect  as  to  admit  of  the  greatest  license, 
as  respects  both  the  fixing  of  the  number  and 
the  apportioning  of  the  parts  which  severally 
belong  to  them.  The  alteration  of  position, 
too,  to  which  they  are  necessarily  subject  to 
enable  them  to  accord  with  the  change  in  direc- 
tion which  the  nervous  matter  sustains,  oasts 
much  confusion  on  the  subject,  and  prevents 
the  mind  from  recognizing,  at  once,  a  similarity 
which  would  be  more  apparent  if  they  con- 
tinued to  be  superimposed  on  each  other  as 
they  are  in  the  spine  instead  of  being  arranged 
at  right  angles  with  it.f 

The  occipital  bone  certainly  offers  no  dif- 
ficulty to  the  detection  of  an  analogy  between 
it  and  a  vertebra;  and  we  readily  discern  in  it 
a  body ;  a  foramen ;  two  transverse,  four  arti- 
cular, and  one  spinous  process;  and  four 
notches.  These  have  already  been  pointed 
out,  and  it  is  sufficient  here  to  observe,  that, 
in  this  bone  apart  from  the  others,  the  basilar 
process  alone  will  represent  the  body,  and  the 
lateral  processes  will  be  the  type  of  the  trans- 
verse processes  of  the  vertebra. 

By  removing  the  bones  of  the  face  and 
taking  the  sphenoid  in  conjunction  with  the 
frontal  bone,  we  shall  (if  we  place  the  body 

*  This  was  Dumeril's  theory.— See  Consid.  gen. 
sur  1' Analogic  entre  tous  les  os  et  les  muscles  du 
tronc  des  animaux.  —  Magasiu  Encyclopedique. 
1808,  t.  iii. 

t  The  celebrated  Goethe  was  among  the  first  to 
adopt  this  idea.  He  admitted  the  existence  of 
three  vertebrae  in  the  cranium,  (Zur  Naturwis- 
senschat't  iiberhaupt,  &c.  Stuttg.  1817-24.)  The 
further  development  of  it  occupied  the  attention 
of  O'Ken,  Spix,  Meckel,  Geoffrey  St.  Hilaire,  and 
Can  s.— bee  Meckel,  Anat.  Desc.  &c.  t.  i.  p.  631, 
and  Carus,  Anat.  Comp.  par  Jourdain,  t.  iii. 
Introduction. — ED. 


CRANIUM. 


741 


of  the  sphenoid  bone  vertically)  at  once  per- 
ceive the  same  analogy  to  exist.  If,  when 
they  are  thus  placed,  we  look  at  the  cerebral 
surface,  we  shall  recognize  the  body  in  that  of 
the  sphenoid  ;  the  vertebral  plates  in  the  small 
wings  of  the  sphenoid,  and  two  halves  of  the 
frontal  bone;  the  foramen  in  the  space  cir- 
cumscribed by  these  last ;  the  transverse 
processes  in  the  two  great  wings  of  the  sphe- 
noid ;  and  the  notches  in  the  lacerated  orbitar 
foramina,  and  the  angles  between  the  body  of 
the  sphenoid  and  posterior  margin  of  its  great 
wings.  If  we  look  at  it  in  front,  it  will  not 
require  any  great  stretch  of  the  imagination 
to  recognize  the  four  articulating  processes  in 
the  pterygoid  processes  of  the  sphenoid  bone 
and  the  external  angular  processes  of  the 
frontal. 

The  temporal  and  the  parietal  bones  toge- 
ther represent  another  vertebra,  situated  be- 
tween the  former  two.  By  looking  at  the 
base  of  the  skull  held  vertically,  and  abstract- 
ing in  the  mind  the  occipital  bone,  we  can 
(under  favour  of  the  license  allowed  to,  or 
taken  by  anatomists)  see  in  the  two  petrous 
portions  of  the  temporal  bones,  if  they  were 
brought  into  contact,  a  type  of  the  body  of  a 
vertebra;  and  in  those  parts  of  them  which 
contribute  to  form  the  anterior  and  posterior 
lacerated  foramina,  we  observe  a  resemblance 
to  those  notches  which  form  in  the  vertebrae, 
as  they  do  here,  conjugal  foramina.  The  arti- 
cular eminences  of  the  temporal  bones  give 
us  no  bad  notion  of  the  transverse  processes, 
while  the  zygomatic  processes  above  (still 
holding  the  skull  vertically)  and  the  part 
which  projects  behind  the  mastoid  processes 
below,  will  indicate  the  four  oblique  or  arti- 
culating processes.  Lastly,  the  squamous  pro- 
cesses of  the  temporal  and  the  whole  of  the 
parietal  bones  represent  the  vertebral  plates, 
and  the  space  enclosed  by  them,  the  vertebral 
foramen. 

Development  of  the  cranial  bones.  —  The 
progressive  development  of  the  bones  of  the 
cranium  has  been  pointed  out  in  their  separate 
descriptions ;  but  there  are  some  general  facts 
which  regard  its  formation  as  an  entire  organ 
which  merit  further  notice. 

The  cranium  of  the  foetus  presents,  like  all 
other  organs,  a  rude  outline  of  the  shape  it  is 
destined  to  assume;  and,  at  the  earliest  pe- 
riod at  which  it  is  noticed,  its  walls  are  com- 
pletely membranous,  being  formed  by  the  dura 
mater  and  pericranium  so  united  as  to  render 
it  impossible  to  separate  them  without  injury. 
Very  early  points  of  ossification  are  developed 
in  this  membranous  envelope,  whence  osseous 
radii  shoot  out,  so  that  the  several  points 
enlarge  towards  each  other,  and  ultimately 
coalesce  or  are  united  by  suture. 

Unlike  other  bones  of  a  similar  character 
the  opposite  surfaces  are  not  of  similar  den- 
sity. The  surface  secreted  by  the  vessels  of 
the  dura  mater  contains  less  animal  matter 
than  that  which  is  produced  from  the  vessels 
of  the  pericranium  ;  and  it  is,  therefore,  of  a 
more  dense  and  brittle  character ;  so  much  so, 


Fig.  375. 


that,  when  the  contiguous  bones  approximate, 
the  edges  of  the  inner  table  are  simply  in 
juxta-position,  a  slight  layer  of  cartilage  alone 
separating  them.  Hence,  in  the  interior  of  the 
skull,  the  sutures  are  plain  lines  ;  or,  if  at  all 
irregular,  there  is  no  interchange  of  substance 
between  them.  Not  so,  however,  with  the 
external.  By  reason  of  the  greater  quantity 
of  animal  matter  which  it  possesses,  and  the 
more  diffuse  character  of  its  texture,  a  prin- 
ciple of  toughness  is  conferred  on  it  which 
admits  of  its  being  dove-tailed  with  the  same 
table  of  other  bones. 

The  base  takes  precedence  of  the  calvaria 
in  the  commencement  and  completion  of  its 
ossification.  With  the  exception  of  its  most 
prominent  points,  and  the  ethmoid  bone,  it  is 
completely  ossified  at  birth;  while,  between 
the  bones  of  the  calvaria,  there  are  conside- 
rable membranous  interspaces,  so  as  to  allow 
of  these  bones  being  squeezed  together,  or  to 
overlap  each  other,  at  the  period  of  parturition. 
The  ossific  matter  departing  from  the  pro- 
tuberances of  the  frontal  and  parietal  bones 
(c,</,/gs.374,375) 
and  radiating  to- 
wards the  circum- 
ference of  these 
bones,  it  follows 
that  the  angles 
will  be  incomplete 
when  the  rest  of 
the  bone  isformed. 
On  this  account  it 
is  that,  at  the  four 
angles  of  each  pa- 
rietal bone,  there 

is  a  membranous  spot  which  the  ossific  matter 
has  not  reached,  when,  in  other  parts,  it  is 
joined  to  the  surrounding  bones.  These 
spaces  are  called  fontanelles ;  two  of  them  are 
situated  on  the  median  line  and  superiorly  ; 
and  two  others  inferiorly  and  in  each  lateral 
region.  The  posterior  superior  fontanelle  is 
triangular,  and  is  found  between  the  superior 
angle  of  the  occipital  bone,  and  the  occipital 
angles  of  the  two  parietal.  The  anterior 
superior  fontanelle  (a, 
jig.  376),  by  reason  of 
the  frontal  bone  being 
formed  in  two  parts,  is 
of  a  lozenge  shape ;  and 
it  is  between  those  two 
parts  and  the  frontal  an- 
gles of  the  parietal  bones 
that  it  occurs.  These  two 
fontanelles  are  conse- 
quently at  the  extremities 
of  the  sagittal  suture. 
The  inferior  fontanelles 
are  found,  the  anterior  (a,  fig.  375)  between 
the  spinous  angle  of  the  parietal,  and  the  great 
wing  of  the  sphenoid  bone;  the  posterior 
(b,  fg.  375)  between  the  mastoid  angle  of  the 
first-named  bone  and  the  mastoid  process  of 
the  temporal.  These  two  fontanelles  are, 
therefore,  situated  at  the  extremities  of  the 
squamous  suture. 


Fig.  376. 


742 


CRANIUM. 


Fig.  377. 


In  infancy  the  rela- 
tive proportion  of  the 
cranium  to  the  face  is 
much  greater  than  in 
adult  life;  and  this 
causes  the  foramen 
m  agnu  m  to  appear  to  be 
situated  much  further 
forward,  in  the  infe- 
rior region  of  the  base, 
than  it  is  when  the 
face  is  more  expanded. 
The  lower  part  of  the  occiput  is  flattened,  the 
superior  is  very  projecting,  and,  altogether, 
the  cranium  has  a  character  of  rotundity  which 
is  speedily  exchanged  for  the  oval  form  which 
prevails  in  the  adolescent  age. 

When  the  sutures  have  become  conjoined, 
and  the  cranium  is  constituted  a  defensive  in- 
vestment of  the  brain  in  virtue  of  its  mechan- 
ism, the  internal  table  (the  tabula  vitrea)  is 
secreted  in  greater  abundance,  and  the  diplb'e 
between  it  and  the  outer  table  is  rendered  more 
manifest.  The  spongy  tissue  of  the  sphenoid 
bone  is  absorbed  and  the  sinuses  formed  ;  but 
it  is  not  until  a  period  nearly  coeval  with 
puberty,  that  those  of  the  frontal  bone  are 
developed. 

It  is  not  until  the  diploe  is  fully  formed  that 
we  can  demonstrate  those  venous  canals  with 
•which  that  structure  has  been  shown  to  abound 
by  the  researches  of  Chaussier,  Dupuytren, 
and  Breschet  (fgss.  187,  188,  p.  436). 

Mechanical  adaptation  of  the  cranium. — It 
will  now  be  noticed  that  the  properties  of  the 
cranium,  those  on  which  its  defensive  qualities 
are  founded,  differ  in  the  several  periods  of 
life;  but  that,  nevertheless,  there  is  in  each 
as  perfect  an  adaptation  of  it  to  these  purposes 
as  seems  consistent  with  the  schemes  of  Provi- 
dence in  the  creation  of  a  finite  being. 

The  pressure  which  the  brain  has  to  sustain 
during  the  process  of  parturition,  is  directed 
solely  to  that  part  which  is  not  essential  to  life ; 
the  condition  of  the  bones  of  the  calvaria  ad- 
mits of  the  volume  of  the  hemispheres  being 
diminished  at  the  time  the  foetus  is  ushered 
into  the  world.  Not  so  the  base ;  the  parts 
which  it  is  destined  to  protect  require  to  be 
maintained  in  all  their  integrity,  and  the  ex- 
tent to  which  it  has  acquired  solidity  is  such 
as  to  forbid  the  encroachment  of  the  parietes  on 
parts  which  are  essential  to  the  continuance  of 
life,  and  which  are  highly  intolerant  of  pres- 
sure. 

In  infantile  life,  also,  protection  is  afforded 
on  the  same  principle.  The  bones  of  the 
calvaria  are  notoriously  capable  of  sustaining 
indentations,  and  afterwards,  by  their  resili- 
ency, of  regaining  their  normal  form.  The 
preponderance,  too,  of  the  organic  over  the 
inorganic  texture,  blunts  the  force  which  may 
be  applied,  and  resists  its  transmission  to  the 
parts  below.  But  there  is  an  addition  even  to 
these  provisions,  a  mechanical  disposition  of 
the  bones  highly  favourable  to  resistance.  At 
the  back,  on  the  sides,  and  in  front — opposed 
in  every  direction  from  which  force  may  pro- 


ceed— are  the  summits  of  ovoidal  domes,  and, 
as  the  ossific  matter  radiates  from  these  summits 
to  the  circumference,  the  force  will  be  received 
on  one  extremity  of  a  bundle  of  diverging 
lines,  and  that  which  would  sever  the  structure 
if  it  fell  on  any  other  point,  here  falls  compa- 
ratively innoxious.  Hence  it  is  that  the  cen- 
ters of  ossification  are  so  much  more  projecting 
during  infancy  than  in  after  life ;  for,  although 
the  mechanical  contrivance  abides  through  the 
whole  term  of  existence,  it  is  not,  when  asso- 
ciated with  other  means,  of  that  predominating 
character  which  we  observe  in  youth. 

The  manner  in  which  the  cranium  (when 
fully  formed)  defends  the  brain,  differs  widely 
from  the  preceding.  In  proportion  as  its 
several  parts  become  consolidated,  and  the 
relation  between  its  animal  and  earthy  consti- 
tuents is  reversed,  so  its  power  of  deadening 
or  neutralizing  the  vibrations  which  pass  through 
it,  is  diminished.  It  is  here  on  its  general 
shape  and  the  disposition  of  its  parts  that  its 
protective  properties  depend. 

It  has  been  already  stated  that  the  bones  of 
the  cranium  are  so  fashioned  as  to  concur  in 
the  production  of  an  egg-like  cavity ;  and  that 
their  margins  are  so  arranged  as  to  enable  them 
to  bind  and  be  bound  by  each  other,  in  such 
a  manner  that  if  one  bone  be  taken  away  the 
whole  will  have  a  tendency  to  separate.  This 
ovoid  form  ensures  (much  better  than  any 
other  which  has  no  fixed  basis  or  point  of 
resistance  beyond  itself)  the  transmission  of 
the  vibrations  which  are  distributed  from  any 
spot  on  which  force  may  be  applied. 

Assuming  that  the  skull  involved  the  pro- 
perties of  an  arch,  its  defensive  power  has  by 
some  been  attributed  to  the  circumstance  of  its 
being  of  that  figure.  An  arched  form,  how- 
ever, would  serve  it  only  in  the  case  of  force 
descending  from  above ;  it  would  not  provide 
resistance  to  those  severe  shocks  which  are 
communicated  from  below,  as  in  jumping, 
nor  protect  it  from  blows  that  might  arrive  on 
its  sides. 

But  the  cranium  is  not  an  arch,  for  there  are 
neither  piers  on  which  the  extremities  of  that 
arch  could  rest,  nor  abutments  to  resist  their 
lateral  thrust.  Supposing  a  barrel  to  be  sawed 
lengthwise,  and  the  edges  to  be  connected  by 
a  base,  if  the  centre  be  applied  on  a  column, 
(the  proportion  of  which  to  the  base  is  the 
same  as  that  of  the  spine  to  the  width  of  the 
skull,)  it  is  manifest  that,  since  the  extremities 
of  the  arch  are  received  on  the  ends  of  two 
long  levers  which  have  a  common  fulcrum,  an 
inconsiderable  force  would  have  a  tendency  to 
sever  them  at  their  junction.  On  the  other 
hand,  if  the  barrel  were  entire,  force  would  be 
transmitted  through  the  parietes  to  a  point 
exactly  opposite  to  that  on  which  it  impinged, 
if  it  were  not  dissipated  in  its  transit.  Such 
a  degree  of  force  however  might  be  applied, 
that  its  vibrations,  distributed  at  the  moment 
of  its  application,  might  pass  through  the  entire 
walls,  and,  accumulating  at  one  spot,  by  their 
intensity  cause  the  fracture  of  the  part.  The 
natural  mode  of  providing  against  this  occur- 


CRANIUM. 


743 


rence  would  be  to  strengthen  the  part  in  which 
(from  the  situation  of  the  organ)  these  vibra- 
tions might,  in  general,  be  expected  to  concur; 
and  this  is  the  contrivance  adopted  in  the  cra- 
nium, for  in  the  centre  of  its  base  there  is  a  qua- 
drilateral portion  (the  body  of  the  sphenoid 
bone)  of  characteristic  massivenessand  strength. 
It  does  not  however  augment  uniformly  in 
its  substance  from  above  downwards.  The 
matter  is  accumulated  in  dense  lines  or  ribs, 
which  pass  to  a  common  centre,  and  constitute 
thereby  a  peculiar  skeleton  or  frame-work  of 
surpassing  strength,  which  admits  of  the  intro- 
duction of  a  lighter  and  more  fragile  structure 
in  the  intervening  spaces,  and  resists  the  shocks 
that  arrive  through  the  spine,  from  behind  or 
from  above. 

This  frame-work  is  situated  almost  entirely 
in  the  base;  the  only  part  which  is  in  the 
calvarium  being  a  longitudinal  curved  line, 
formed  by  the  ethmoidal  process  of  the  sphe- 
noid bone,  the  crista  galli  of  the  ethmoid,  the 
spine  of  the  frontal,  the  thickened  commutual 
margins  of  the  parietals,  and  the  superior  limb 
of  the  internal  occipital  spine.  Independently 
of  this  curved  rib,  the  calvarium  consists  of 
four  ovoidal  domes,  two  on  each  side;  formed, 
the  anterior  by  the  corresponding  half  of  the 
frontal  bone,  and  the  posterior  by  the  parietal. 
The  summits  of  these  domes  are  their  centres 
of  ossification,  and  their  bases  abut,  partly  on 
the  longitudinal  rib,  and  partly  on  the  frame- 
work in  the  base. 

The  part  to  which  all  the  forces  tend  is  the 
body  of  the  sphenoid  bone.  From  its  posterior 
corners  there  pass  backwards  two  ribs,  (the 
petrous  processes  of  the  temporal  bones,) 
which  terminate  on  the  extremities  of  an  arch, 
(the  lateral  limbs  of  the  internal  crucial  spine 
of  the  occiput,)  which  is  placed  horizontally, 
and  the  convexity  of  which  is  turned  back- 
wards. 

This  arch  and  the  two  ribs  which  connect  it 
to  the  centre  are  in  the  line  in  which  the  oc- 
ciput would  strike  the  ground  in  falling  back- 
wards ;  and  they  further  form  the  brim  of  the 
pit  which  contains  the  cerebellum,  so  that  the 
vibrations  of  force  pass  in  the  interstice  between 
that  organ  and  the  cerebrum. 

From  each  side  of  the  body  of  the  sphenoid 
bone  there  stretches  forwards,  outwards,  and 
upwards  towards  the  temples,  a  curved  rib, 
(the  anterior  part  of  the  great  wing,)  and,  from 
the  anterior  part  of  the  body,  a  transverse  rib 
which  overlays  the  former.  These  and  the 
posterior  lateral  ribs,  all  of  which  depart  from 
a  common  centre,  constitute  the  frame-work  of 
the  base  which  sustains  the  ovoidal  domes  of 
the  calvaria.  The  frontal  dome  is  placed  with 
its  summit  (the  frontal  depression)  looking 
backwards,  downwards,  and  inwards ;  its  mar- 
gin is  received,  inferiorly  on  the  whole  length 
of  the  anterior  transverse,  and  on  the  extremity 
of  the  anterior  lateral  curved  rib;  towards  the 
middle  line,  on  so  much  of  the  longitudinal 
rib  as  extends  to  the  parietal  bones  ;  and  supe- 
riorly, it  is  applied  against  a  portion  of  the 
base  of  the  parietal  dome.  It  is  against  these 
parts  that  it  thrusts,  whenever  it  receives  a 


shock  on  its  summit.  The  parietal  dome  is 
placed  with  its  summit  (the  parietal  depression) 
looking  downwards  and  inwards.  Below,  it 
is  received  on  the  extremities  of  the  lateral 
ribs ;  above,  it  thrusts  against  the  remainder  of 
the  longitudinal  rib;  behind,  it  falls  on  the 
corresponding  portion  of  the  horizontal  arch  ; 
and,  in  front,  it  antagonizes  the  frontal. 

It  is  by  the  bases  of  these  domes  thus 
thrusting  against  a  solid  frame-work,  that  the 
cranium  is  endowed  with  the  power  of  re- 
sisting lateral  shocks  whether  they  approach 
from  before  or  behind ;  and  it  is  not,  as  some 
allege,  simply  by  the  mobility  of  the  head, 
that  it  withstands  blows,  which,  if  it  were 
fixed,  would  fracture  it. 

There  yet  remains  to  be  noticed  an  impor- 
tant part  of  this  skeleton  or  frame-work ;  that 
which  bears  upon   the  spine,  and  resists  the 
force  transmitted  through  it.     At  the  bottom  of 
the  pit  containing  the  cerebellum,  there  is  an 
elliptical  opening  (the  foramen  magnum),  the 
margin  of  which  is  very  dense;  this  opening  is 
provided  underneath  with  two  tubercles  (the 
articulating  processes),  by  which  it  rests  on  the 
vertebral  column;  from  these  tubercles  a  curved 
rib  on  each  side  (the  lateral  process  of  the  oc- 
cipital bone  and  the  mastoid  of  the  temporal) 
extends  upwards  and  outwards  to  the  extremity 
of  the  posterior  lateral  rib ;  the  segment  of  the 
margin  of  the  opening  which  is  anterior  to  the 
tubercles,  is  prolonged  upwards  and  forwards, 
in  the  form  of  a  broad  pillar  (the  basilar  pro- 
cess), to  the  back  part  of  the  common  centre ; 
the   segment    which  is   behind   the   tubercles 
sends  off,  at  its  back  part,  a  spine  (the  inferior 
limb  of  the  internal  crucial  spine),  which  ends 
at  the  centre  of  the  horizontal  arch,  at  the  point 
where  the  superior  longitudinal  rib  terminates ; 
and  this  point  of  confluence  of  the  forces  from 
below,  from  above,  and  from  behind,  is  strength- 
ened by  a  nodule  (the  internal  occipital  protu- 
berance).     The  frame-work  of  the  cerebellar 
cavity  is  thus  connected  with  that  of  the  general 
cavity;  anteriorly,  to  the  body  of  the  sphenoid 
bone;  posteriorly,  to  the  tubercle  of  the  occi- 
pital ;  and,  laterally,  to  the  extremities  of  the 
petrous  processes  of  the  temporal  bones.     In 
both  of  them  it  will  be  seen  that  they  occupy 
spaces  between  the  grand  divisions  of  the  ner- 
vous matter,  which  latter  is,  therefore,  removed 
from  the  chance  of  sustaining  injury  by  shocks, 
much  more  completely  than  it  could  have  been 
had  the  parietes  been  submitted  to  a  progres- 
sive  augmentation   of    substance   from   above 
downwards.     As  it  is,  the  spaces  in  which  the 
nervous  matter  reposes  are  thin  and  frequently 
diaphanous;  and,  were  they  situated  in  un- 
protected parts,  would   be   perforated  by  the 
slightest  force. 

During  a  considerable  period  of  life  the  sub- 
ject enjoys  additional  protection  from  the  slight 
yielding  of  the  bones,  and  from  the  cartilage 
which  intervenes  especially  at  the  base.  Pres- 
sure applied  on  the  vertex  would  tend  to  disjoin 
the  parietal  bones  from  each  other,  and  from 
the  frontal  and  occipital  bones.  This  the  pe- 
culiar nature  of  the  articulations  forbids,  and 
the  longitudinal  rib  chiefly,  and  the  expanded 


744 


CRANIUM. 


portion  of  the  bones  themselves  in  part,  convey 
the  force  downwards,  the  former  forwards 
through  the  median  line  of  the  ethmoid  to  the 
front  of  the  sphenoid,  and  backwards  through 
the  superior  and  inferior  limbs  of  the  crucial 
spine  of  the  occiput,  traversing  the  foramen 
magnum,  and  passing  through  the  basilar 
process  to  the  back  of  the  sphenoid  bone: 
the  latter  forwards  through  the  frontal  bone 
to  the  small  and  great  wings,  and,  through 
them,  to  the  body  of  the  sphenoid ;  and 
backwards  through  the  parietal  and  occipital 
to  the  lateral  limbs  of  the  crucial  spine. 
The  parietals  convey  it  down  the  sides  to 
the  great  wing  of  the  sphenoid  and  the  mas- 
toid  ^process  of  the  temporal  bone,  from  which 
it  is  transmitted  to  the  common  centre ;  and 
the  slight  rotation  which  is  permitted  to  the 
temporal  bone,  (and  which  has  already  been 
alluded  to,)  materially  tends  to  break  the  force 
in  its  transit.  Nor  is  there  any  imperfection  in 
this  apparent  inclination  of  the  parietals  to  an 
outward  divergence,  for  the  squamous  process 
of  the  temporal  bone  which  overlaps  each  be- 
tween its  two  fixed  points  is  strongly  supported 
on  its  outer  side  by  the  temporal  muscle. 

ABNORMAL  CONDITIONS  OF  TUB  CRANIUM. 

Most  of  the  abnormal  conditions  of  the  cra- 
nium are  dependent  on  circumstances  con- 
nected with  the  evolution  of  the  brain,  and 
are  mostly  acquired  after  birth ;  the  only  con- 
genital variations  being  those  in  which  there  is 
a  total  or  a  partial  privation  of  its  parietes. 

There  is  no  vestige  of  it,  or,  indeed,  of  the 
head  itself,  in  the  true  acephalous  foetus ;  but, 
whenever  the  medulla  oblongata  is  present,  the 
base  of  the  cranium  is  developed,  and  often- 
times there  are  found  rudimentary  portions  of 
the  other  bones  (false  acephalia  and  anence- 
phalia) . 

The  parietal  or  occipital  bones,  and  some- 
times all  of  them  are  imperfect  in  that  mal- 
formation termed  encephalocele,  which,  in 
some  cases,  is  analogous  to  spina  bifida,  and, 
in  others,  to  hernia  cerebri.  When  serous  fluid 
constitutes  the  tumour,  the  deficiency  of  the 
bones  is  considerable,  owing  to  the  airestation 
of  the  formative  process;  but  when  the  brain 
protrudes,  their  development  continues  in  such 
a  way  as  to  embrace  the  root  of  the  tumour,  and 
then  the  calvaria,  flattened  and  in  contact  with 
the  base,  exhibits  an  opening  through  which 
the  hernia  escaped. 

The  cranium  is  said  to  be,  at  times,  insuffi- 
ciently evolved ;  the  evolution  of  its  parts  being 
accelerated  and  their  coalescence  prematurely 
effected,  so  that  the  ossific  capsule  is  formed 
before  the  brain  has  attained  its  full  growth. 
It  is,  however,  most  probable  that  in  this  as  in 
other  cases  it  adapts  itself  to  the  brain,  and 
that  it  is  on  an  imperfect  development  of  that 
organ  that  the  smallness  of  the  cranium  is  de- 
pendent ;  but  varieties  of  this  description  which 
are  connected  with  deficiences  of  mental  en- 
dowment will  scarcely  admit  of  enumeration. 

The  parietes  of  the  cranium  may  be  preter- 
naturally  thin,  without  this  being  dependent  on 
disease ;  but  they  are  most  obviously  in  that 


condition  in  hydrocephalus,  in  which  affection, 
however,  there  are  two  opposite  states  of  the 
skull. 

When  the  disease  occurs  in  infancy,  and 
persists  for  any  length  of  time,  the  bones  of 
the  calvaria  usually  become  thin  and  pellucid ; 
the  spaces  between  them  are  of  great  extent ; 
and  the  deposition  of  the  inorganic  texture 
is  arrested  in  such  a  way  that  instead  of 
bones  we  have  frequently  little  more  than  a 
membrane- cartilaginous  lamina,  and  some- 
times not  even  that;  for  instances  have  been 
known  in  which  the  upper  part  of  the  head 
has  been  covered  by  membrane  only.  This 
suspension  of  action,  however,  is  in  some 
instances  only  temporary.  The  deposition  of 
ossific  matter  becomes  then  more  rapid  and 
abundant  than  under  ordinary  circumstances ; 
the  points  of  deposit  are  more  numerous  than 
usual ;  and  a  skull  of  gigantic  dimensions  and 
of  peculiar  and  premature  hardness  is  pro- 
duced. 

It  has  been  sufficiently  explained  that  the 
several  ossific  elements  of  the  cranium  unite  in 
definite  numbers  to  produce  the  bones  which 
we  have  been  occupied  in  describing.  Never- 
theless, it  not  unusually  happens  that  some  of 
these  elements,  or,  otherwise,  adventitious  de- 
posits of  a  similar  character,  which  manifest 
themselves,  do  not  flow  into  and  combine 
with  the  other  elements  of  the  bone  in  which 
they  occur ;  but,  on  the  contrary,  each  in  itself 
forms  the  centre  of  an  ossific  process,  arid  the 
bone  thus  formed  (be  it  large  or  small)  articu- 
lates by  its  circumference  to  the  parts  with 
which  it  comes  into  contact.  These  adven- 
titious pieces  are  commonly  known  under  the 
name  of  ossa  Wormiana,  because  it  is  supposed 
that  they  were  first  described  by  Wormius,  a 
physician  at  Copenhagen  in  the  seventeenth 
century;*  they  are  also  called  ossa  triquetra, 
triangularia,  ossa  suturarum,  ossa  supranume- 
raria.  They  vary  in  situation,  number,  and 
size.  In  general  they  are  situated  in  the 
lambdoidal  suture ;  they  are,  however,  met  with 
in  the  sagittal,  occasionally  in  the  coronal,  and 
(though  rarely)  in  the  squamous  suture.  One 
of  the  most  remarkable  is  that  which  sometimes 
replaces  the  superior  angle  of  the  occipital 
bone,  called  by  Blasius  os  triangulare  or  epac- 
tate.  Berlin  describes  one  in  the  situation  of 
the  anterior  fontanelle. 

It  is  by  a  process  analogous  to  the  pre- 
ceding that  the  occipital  bone  occasionally 
presents  a  suture  between  the  upper  and  under 
halves  of  its  posterior  portion.  The  elements 
of  those  two  parts  combine  among  themselves, 
and  the  pieces  resulting  from  their  union  ap- 
proach, and,  instead  of  forming  the  continuous 
bone,  as  we  usually  see  it,  they  are  associated 
by  means  of  an  additional  suture. 

An  anomaly  of  not  very  unusual  occurrence 
is  the  permanence  of  the  suture  uniting  the 
two  halves  of  the  frontal  bone,  and  which  is 
seldom  apparent  beyond  the  second  year  of 
extra-uterine  life. 


*  Vid.  Ol.  Wormii  et  ad  eum  doctorum  virAm 
epistolae,  t.  5.  Hafniae,  1728. 


CRANIUM. 


745 


There  are  but  few  skulls  which  are  perfectly 
symmetrical,  although  the  variation  of  one  side 
from  the  other  is  generally  so  slight  that  the  eye 
does  not  at  once  detect  it.  In  numerous  cases, 
however,  the  want  of  symmetry  forcibly  obtrudes 
itself;  sometimes  one  half  is  considerably  larger 
than  the  other ;  and  in  other  cases  it  appears 
to  be  thrown  out  of  position,  as  though,  during 
the  time  that  the  parietes  were  soft,  pressure 
had  been  applied  in  front  and  behind,  and,  by 
a  sort  of  rotatory  movement,  it  had  been  drawn 
back  on  one  side  and  pushed  forward  on  the 
opposite.  There  does  not  appear  to  be  an 
absolute  uniformity  among  the  skulls  of  this 
description  saving  that  the  projections  are 
always  situated  diagonally  with  respect  to  each 
other ;  that  is,  if  it  be  twisted  to  the  right,  the 
right  half  of  the  frontal  bone  will  be  in  advance 
of  the  left ;  while  the  posterior  part  of  the  left 
parietal,  and  the  corresponding  side  of  the 
occipital  bone,  will  project  behind  the  right. 
This  is  by  far  the  most  prevalent  variation,  but, 
occasionally,  the  left  half  of  the  frontal  bone  is 
in  advance,  and,  in  such  instances,  the  posterior 
increase  will  be  on  the  right  side. 

The  change  which  takes  place  in  advanced 
age  can  scarcely  be  accounted  an  anomaly.  At 
that  period  the  skull  is  much  more  an  entire 
bone  than  it  is  in  the  earlier  epochs.  The 
sutures  are  to  a  certain  extent  effaced,  and  a 
mere  line  indicates  the  former  disjunction  of 
the  bones.  It  is  on  the  interior  of  the  skull 
that  these  sutures  are  first  effaced,  and  on  the 
exterior  the  order  of  obliteration  is  from  the 
summit  to  the  base.  It  has  been  affirmed  that 
the  volume  of  the  skull  diminishes  in  old  age, 
and  that  it  is  susceptible  of  change,  in  different 
directions,  after  the  bones  are  locked  together. 
It  is,  however,  certain  that  its  external  con- 
figuration is  somewhat  altered,  for  the  promi- 
nences formed  by  the  centres  of  ossification  of 
the  parietal  and  frontal  bones  become  flattened 
and  undistinguishable  from  the  rest  of  the 
parietes;  which,  as  old  age  sets  in,  become 
thinner  than  they  were  previously.  This  change, 
however,  is  but  temporary,  for,  in  extreme  old 
age,  the  skull  is  thicker  and  more  porous  than 
at  any  antecedent  period  of  life.  This  hyper- 
trophy is  produced  by  the  recession  of  the 
inner  from  the  outer  table,  and  the  conversion 
of  some  part  of  the  substance  of  each  into  a 
thin  spongy  tissue ;  the  diploe  itself  sustaining 
an  analogous  alteration,  by  the  enlargement  of 
its  cells,  and  the  thinning  of  the  plates  which 
form  their  walls. 

Occasional  instances  occur  in  which  the 
skull  is  of  inordinate  thickness,  and  this,  appa- 
rently, without  its  being  connected  with  the 
age  of  the  subject.  The  late  Mr.  Joshua  Brookes 
had  some  sections  of  a  skull,  found  in  a  church- 
yard in  Lancashire,  of  nearly  three  quarters  of 
an  inch  in  thickness;  and  specimens  have  been 
seen  of  more  than  an  inch.  In  some  of  them 
the  diploe  is  perfect,  the  augmentation  being  in 
the  two  tables ;  in  others,  and  indeed  in  the 
majority  of  specimens,  the  two  tables  and  the 
diploe  are  confounded  together  in  one  thick 
mass  of  matter,  which  is  of  an  ivory  hardness.  It 
is  not  improbable  that  we  might  justly  refer  this 

VOL.  I. 


condition,  as  well  as  some  other  peculiarities  of 
the  cranium,  to  inflammation  of  the  bone  itself, 
or  of  its  investing  membranes.  That  exostosis 
is  the  product  of  a  limited  periostitis  admits  of 
but  little  dispute,  and  it  is  very  likely  that  those 
cases  of  hyperostosis  in  which  there  is  a  uniform 
deposit  of  bone,  only  mark  the  effect  of  a  more 
diffused  and  general  inflammation ;  the  more 
so,  since  we  meet  with  these  local  and  general 
deposits,  as  well  on  the  inner,  as  on  the  outer 
table  of  the  skull,  and  for  the  existence  of  which 
it  would  otherwise  be  impossible  to  account. 

When  they  occur  on  the  inner  table,  the  func- 
tions of  the  brain  are  usually  more  or  less  dis- 
turbed, although  it  would  appear  that  the  mental 
manifestations  are  not  always  implicated.  In 
the  skull  of  an  idiot  of  advanced  age,  examined 
several  years  since  by  the  writer  of  this  article, 
there  was  a  uniform  deposition  to  the  extent  of 
nearly  a  quarter  of  an  inch ;  and  in  a  recent  autopsy 
of  a  young  girl,  he  found  the  entire  syncipital 
region  very  irregular  in  its  surface,  from  being 
studded  with  variously-sized  nodules,  the  bases 
of  which  flowed  into  and  were  lost  in  each  other. 
This  girl  was  of  feeble  intellect,  and  the  victim 
of  epilepsy.  In  the  examination  of  a  body  at 
the  Hotel  Dieu,  by  Mr.  King,  that  gentleman 
discovered  on  the  petrous  portion  of  the  tem- 
poral bone  a  tumour  which  he  had  not  been  led 
to  expect  by  any  indication  of  suffering  which 
appeared  during  life.  This  tumour  had  the 
volume  of  a  marble  or  pistol-bullet,  was  cel- 
lular in  its  structure,  and  perfectly  smooth  on 
its  surface ;  a  depression  exactly  corresponding 
to  it  was  found  on  the  under  surface  of  the 
middle  lobe  of  the  brain,  but  its  substance  and 
membranes  had  their  normal  characters. 

The  cranium  is  oftentimes  found  in  the  oppo- 
site state  of  atrophy,  in  which  the  balance  be- 
tween deposition  and  absorption  seems  to  have 
been  disturbed,  so  much  to  the  prejudice  of 
the  former,  that  the  walls  are  sometimes  not 
much  thicker  than  a  piece  of  paper.  When- 
ever the  two  textures  maintain  their  usual  pro- 
portion, this  atrophy  may  be  regarded  as  a 
natural  abnormal  state;  but  those  cases  in 
which  either  the  inorganic  or  animal  element 
preponderates,  and  a  fragility  or  softening  of 
the  bone  is  thereby  established,  must  be  referred 
to  some  constitutional  affection  in  which  the 
rest  of  the  osseous  system  has  participated, 
and  the  influence  of  which  it  will  not  fail  to 
exhibit. 

In  addition  to  exostosis  and  hyperostosis,  the 
cranium  sustains  other  pathological  changes  as 
the  effects  of  inflammation. 

Previously  to  the  establishment  of  osteitis, 
whether  from  a  common  or  specific  cause, 
mercurial  or  syphilitic,  there  is  found  that  stasis 
of  the  blood  which  always  precedes  inflam- 
mation. The  sanguineous  complexion  of  the 
diploe  in  cases  of  erysipelas  testifies  that  this 
engorgement  may  be  produced  by  increased 
action  in  the  neighbouring  teguments. 

It  has  already  been  stated  that  hypertrophy 
of  the  cranium  may  be  regarded  as  a  termina- 
tion of  osteitis.  When  inflammation  is  limited 
in  its  action  and  of  long  duration,  it  is  probable 
that  the  ossific  element  is  poured  into  the  cells 


746 


REGIONS  AND  MUSCLES  OF  THE  CRANIUM. 


of  the  diploe  so  as  to  effect  their  obliteration ; 
but  when  it  is  of  a  more  vivid  character,  the 
opposite  effect  of  softening  (the  precursor  of 
ulceration)  takes  place,  and  both  the  outer  and 
inner  tables  are  rendered  friable.  This  fre- 
quently occurs  to  a  great  extent  in  the  mastoidal 
cells,  especially  in  children ;  and  as,  in  them, 
the  posterior  portion  of  the  meatus  auditorius 
internus  possesses  an  unclosed  fissure,  the  dis- 
charge which  is  consequent  on  the  destruction 
of  the  cells  is  allowed  an  exit,  before  the  mem- 
brana  tympani  is  destroyed  ;  although  that,  as 
well  as  the  whole  of  the  internal  ear,  is  fre- 
quently involved  in  the  ravages  of  the  disease — 
then,  however,  having  passed  into  another  ter- 
mination of  osteitis,  viz.  ulceration. 

Adhesion  can  take  place  only  where  the  cra- 
nium has  experienced  a  lesion  from  a  mechani- 
cal cause;  and  it  is  altogether  prevented  if  the 
solution  of  continuity  be  great.  The  edges  of  a 
wound,  produced  by  a  cutting  instrument 
penetrating  more  or  less  perpendicularly  to  the 
surface  of  the  bone,  do  not  approximate;  but 
they  are  united  by  an  interposing  callus  as  in 
the  case  of  a  common  fracture,  and  the  line 
formed  by  it  is  always  visible  in  the  same 
way  as  the  cicatrix  which  persists  after  the  ad- 
hesion of  soft  parts.  When  a  piece  of  the 
outer  plate  is  elevated  by  a  cutting  instrument 
passing  very  obliquely  to  the  surface  of  the  bone, 
and  the  scalp  is  not  detached,  it  will,  on  being 
immediately  re-applied,  unite  with  the  surface 
from  which  it  has  been  raised ;  and,  if  it  be 
altogether  removed,  the  reparation  will  be 
effected  in  the  same  way  as  in  other  parts,  viz. 
by  the  granulation  and  cicatrization  of  the  cut 
surface. 

When  there  is  loss  of  substance  of  the  entire 
thickness  of  the  bone,  whether  that  loss  be  pro- 
duced by  mechanical  or  pathological  causes, 
granulations  spring  up  from  the  dura  mater; 
the  edge  of  the  opening  becomes  very  thin; 
the  surface  cicatrizes  and  produces  the  appear- 
ance of  a  dense  fibrous  membrane,  the  circum- 
ference of  which  is  attached  to  the  margin  of  the 
hole  and  the  adjacent  pericranium. 

Caries,  which  is  analogous  to  ulceration  of 
the  soft  parts,  and  is,  in  fact,  an  ulcerative  ab- 
sorption of  bone,  attacks  the  cranium  in  com- 
mon with  the  rest  of  the  osseous  system ;  but  it 
always  first  appears  on  one  of  the  two  tables, 
and  not  on  the  diploe,  although  ultimately  the 
entire  thickness  is,  in  some  cases,  involved. 
•  Indeed,  when  it  commences  on  the  inner  table, 
it  is  only  by  the  extension  of  the  ulcerative  pro- 
cess through  the  substance  of  the  bone,  that 
the  suppurative  collection  can  be  emancipated. 

In  this  affection  the  pericranium  is  sometimes 
enormously  thickened  and  almost  inseparably 
attached  to  the  rough  biscuit-like  surface  of  the 
bone  beneath.  In  other  cases,  especially  in 
those  in  which  the  ulcerative  process  has  been 
provoked  by  mercury,  it  is  in  irregular  patches; 
the  pericranium  is  unattached  and  the  denuded 
surface  is  of  a  dark  colour. 

Necrosis,  or  mortification  of  the  bone,  is  of 
frequent  occurrence ;  but  not  in  the  way  usually 
implied  by  that  term.  Whether  it  be  the  sub- 
stance of  the  bone,  or  merely  its  outer  lamina 


which  is  deprived  of  its  vitality,  the  reparation 
is  not  by  a  fresh  deposition  of  bone,  nor  is 
it  coeval  with  the  separation  of  the  necrosed 
part,  as  in  the  long  bones ;  but  it  is  a  subse- 
quent action  (such  as  has  been  already  pointed 
out)  which  is  established  to  supply  the  loss. 
Considerable  portions  of  the  frontal  and  parietal 
bones  may  thus  be  thrown  off  and  the  deficiency 
provided  for  by  the  granulations  of  either  the 
subjacent  diploe  or  the  dura  mater. 

Medullary  sarcoma  sometimes  manifests 
itself  in  the  cranium.  It  appears  to  commence 
in  the  diploe  by  a  deposition  of  tuberculous 
matter,  which  softens,  and  which  in  that  state 
may  be  mistaken  for  pus;  the  inorganic  ele- 
ment is  withdrawn ;  the  accumulation  con- 
tinues and  advances  towards  both  tables,  which 
in  turn  submit  to  the  same  change  of  structure; 
and, ultimately,  a  tumour  is  formed,  the  capsule 
of  which  is  constituted,  on  the  one  side  by  the 
pericranium,  and,  on  the  other,  by  the  dura 
mater.  In  this  tumour  the  knife  detects  spiculae 
of  bone  interspersed  throughout  its  substance, 
and  the  edge  of  the  opening  which  is  left  in  the 
skull  after  maceration,  is  studded  with  irregular 
projecting  points. 

For  the  Bibliography,  see  OSSEOUS  SYSTEM. 
( J.  Malyn.) 

CRANIUM,  REGIONS  AND  MUSCLES 
OF  THE,  (Surgical  Anatomy.)— If  a  line  be 
drawn  on  the  skull  from  the  external  angular 
process  of  the  frontal  bone,  backwards  along 
the  rough  line  on  that  and  the  parietal  bone, 
which  indicates  the  attachment  of  the  temporal 
fascia,  be  continued  downwards  and  backwards 
parallel  and  a  little  external  to  the  occipito- 
mastoid  suture,  and  then  be  carried  forwards 
along  the  inferior  surface  of  the  occipital  bone  to 
end  just  behind  the  foramen  jugale,  and  a  little 
internal  to  the  stylo-mastoid  foramen, — this 
line,  with  another  similar  one  on  the  other  side, 
will  include  an  oblong  region  which  has  very 
natural  limits  both  before  and  behind.  Ante- 
riorly this  region  is  limited  on  each  side  by  the 
anterior  margins  of  the  roof  of  the  orbit,  in 
the  centre  by  the  line  of  articulation  of  the 
frontal  bone  with  the  nasal  and  superior  maxil- 
lary, posteriorly  by  the  superior  curved  line  of 
the  occipital  bone,  and  on  each  side  by  the 
mastoid  process.  To  this  oblong  region  may 
be  appropriately  given  the  designation  occipito- 
frontal  region. 

The  line  which  thus  limits  laterally  the  region 
just  named  circumscribes  another  region  which 
occupies  nearly  the  whole  lateral  surface  of  the 
cranium,  and  which  is  called  the  temporo- 
purietal  region.  This  region  passes  into  the 
base  of  the  cranium,  and  may  be  limited  below 
and  within  by  a  line  from  the  styloid  process 
external  to  the  glenoid  cavity,  as  far  as  the 
spheno-maxillary  fissure.* 

*  Bland  in  makes  five  cranial  regions — occipito- 
frontal,  temporal,  auricular,  mastoid,  and  the  region 
of  the  base  of  the  cranium  :  the  last  is  quite  out 
of  the  reach  of  the  surgeon,  and  therefore  is 
excluded  from  consideration  in  the  present  article. 
Velpeau  has  three  regions, — the  frontal,  temporo- 


REGIONS  AND  MUSCLES  OF  THE  CRANIUM. 


I.  Occipito-frontal  region. — The  anterior  and 
posterior  boundaries  of  this  region  are  suffi- 
ciently obvious  on  the  integuments,  the  eye- 
brows forming  the  anterior,  the  posterior  being 
constituted  by  a  line  extending  as  far  as  the 
mastoid  process  on  each  side  of  the  occipital 
protuberance  corresponding  to  the  insertion  of 
the  superficial  muscles  of  the  back  of  the  neck, 
which  protuberance  can  be  felt  through  the 
integuments.  The  lateral  limits,  however,  are 
not  so  distinct ;  in  the  living  subject,  however, 
when  the  temporal  muscle  is  rendered  tense,  a 
distinct  line  of  demarcation  is  felt  along  the 
upper  margin  of  this  muscle,  extending  down- 
wards and  backwards  nearly  as  far  as  the  mas- 
toid process. 

We  proceed  to  examine  the  several  structures 
which  are  presented  to  the  anatomist  as  he 
pursues  the  dissection  of  this  region. 

1.  Integument. — It  is  in  this  region  that  we 
can  best  examine  the  general  characters  of  the 
integument  of  the  cranium,  commonly  known 
under  the  name  of  scalp  (Fr.  cuir  chevelu). 
The  greatest  part  of  it  is  remarkable  for  the 
more  or  less  luxuriant  growth  of  hair  from  it,* 
the  nature  of  which,  it  is  hardly  necessary  to 
observe,  differs  materially  in  the  male  and  in 
the  female.  In  the  natural  state  about  two- 
thirds  or  three-fourths  of  the  scalp  are  covered 
with  hair,  the  anterior  third  or  fourth, — namely, 
the  skin  of  the  forehead, — being  uncovered. 
In  front  the  hairs  terminate  abruptly  on  the 
frontal  region ;  behind  they  terminate  less  ab- 
ruptly, and  descend  in  general  to  a  variable 
distance  on  the  posterior  part  of  the  neck, 
becoming  finer  and  more  downlike  as  they 
descend.  The  natural  direction  of  the  hairs 
is  at  right  angles  with  that  portion  of  the  scalp 
from  which  they  grow;  consequently  the  dif- 
ference of  direction  of  the  hairs  depends  upon 
the  differences  in  the  aspects  of  those  regions. 
This  is  most  obvious  in  that  part  of  the  head 
which  is  called  the  crown,  which  in  most  per- 
sons inclines  downwards  and  backwards  to  a 
greater  or  less  extent.  Such,  however,  is  the 

parietal,  and  occipito-mastoid.  The  advantages  to 
be  derived  from  the  subdivision  of  the  body  into 
so  many  small  regions  as  is  adopted  by  the  French 
anatomists,  are  by  no  means  obvious.  I  decidedly 
prefer  a  subdivision  which  is  indicated  by  certain 
naturally  prominent  points  or  landmarks,  which 
will,  1  think,  in  general  be  found  to  map  out 
regions  not  too  limited  nor  too  numerous,  nor  yet 
too  comprehensive. 

*  We  cannot  resist  the  temptation  of  transcribing 
the  following  passage  from  Gerdy,  which  is  not 
devoid  of  some  national  characteristics.  "  La 
surface  superieure  de  la  tete  est  arrondie  et  ovo'ide. 
Elle  est  couverte  par  les  cheveux  qui  en  cachent 
les  formes,  lui  donnent,  par  la  soupplesse  et  le 
contraste  de  leur  couleur,  une  sorte  de  beaute  dif- 
ficile a  exprimer,  et  fournissent  au  gout  delicat  des 
femmes  Fornement  le  plus  gracieux  et  le  plus  se- 
duisant  par  les  masses  legeres,  les  guirlandcs  flex- 
ueuses,  les  boucles  arrondies  qu'elies  en  composent, 
et  par  les  mille  arrangemens  que  suggere  a  leur 
imagination  1'amour  ou  Part  de  plaire.  Mais  la 
tete,  se  depouillant  avec  1'age,  de  la  chevelure 
qui  Pembellisait,  ne  presente  plus  dans  la  vieillesse 
qu'une  surface  nue  et  luisante,  ou  Ton  entrevoit 
quelqtiefois  la  trace  des  sutures  frontales  et  parie- 
tales." 


747 

influence  of  art  in  the  arrangement  of  the  hair, 
that  it  is  difficult  to  meet  with  "  a  head  of 
hair"— to  borrow  the  phrase  from  the  hair- 
dresser,— where  the  growth  is  perfectly  na- 
tural. 

There  is  an  obvious  difference  in  the  nature 
of  that  portion  of  the  scalp  from  which  hairs 
grow,  and  that  which  is  naturally  bald:  the 
former  is  much  thicker  and  denser,  owing,  no 
doubt,  to  a  larger  developement  of  the  fibres 
of  the  cor  ion,  and  to  the  great  magnitude  of 
the  hairs  which  pierce  it.  It  is  at  the  posterior 
part  of  the  occipito-frontal  region  that  the  hairs 
are  strongest,  and  that  portion  of  the  scalp 
very  rarely  becomes  bald. 

2.  Subcutaneous    tissue. — Subjacent  to   the 
integument  is  a  dense  and  lamellated  cellular 
tissue,  with  little  fat,  and  such  as  does  exist 
deposited  in  small  pellets,  much  more  nume- 
rous in  the  posterior  part  of  the  region.     This 
cellular  membrane  is  very  intimately  connected 
with  those  parts  of  the  scalp  especially  from 
which  hairs  grow  ;  it  is  much  more  loose  and 
less  adipose  in  the  frontal  region ;  it  also  ad- 
heres pretty  closely  to  the  subjacent  aponeurotic 
expansion    of    the    occipito-frontalis    muscle. 
The  bulbs  of  the  hairs  are  lodged  in  it.     The 
firm  adhesion  of  this  cellular  membrane  on 
the  one  hand  to  the  skin,  and  on  the  other  to 
the  subjacent  aponeurosis,  is  sufficient  to  ac- 
count for  the  great  pain  and  danger  which  at- 
tend punctured  wounds  of  the  scalp,  in  conse- 
quence of  the  non-extensibility  of  the  membrane 
and  the  tension  which  a  very  slight  degree  of 
swelling  consequently  gives  rise  to. 

3.  Muscles. — If  the  scalp  and  subcutaneous 
tissue  be  divided  by  a  transverse  incision  over 
the  vertex,  and  the  flaps  carefully  dissected  off, 
— one  as  far  as  the  eyebrows,  the  other  to  the 
superior  curved  line  of  the  occipital  bone,  the 
occipito-frontalis  muscle  is  brought  into  view. 
Anteriorly  and  inferiorly  we  find  the  few  fibres 
of  the  orbicularis  palpebrarum  muscle  overlap- 
ping the  occipito-frontalis  just  above  the  mar- 
gin of  the  orbit. 

Occipito-frontalis  (epicraniust  Albin.  :  de- 
scribed by  some  anatomists  as  two  distinct 
muscles,  the  frontal  and  occipital). 

This  is  an  expanded  digastric  muscle  occu- 
pying the  whole  of  this  region.  The  two  bellies 
of  which  the  muscle  is  composed  are  united  in 
the  centre  by  a  broad  aponeurotic  expansion. 
The  anterior  belly  corresponds  to  a  great  part  of 
the  frontal  bone,  and  the  posterior  to  a  part  of 
the  occipital.  Very  frequently  the  fibres  are 
weak  and  pale,  so  that  the  dissector  finds  it 
difficult  to  trace  out  the  extent  and  attachments 
of  the  muscle ;  and,  moreover,  even  in  its  most 
developed  state  it  is  a  thin  muscle,  so  that  great 
care  is  required  for  the  accurate  dissection  of  it. 

The  anterior  belly  of  this  muscle,  or  that 
which  is  by  some  called  the  frontal,  consists 
distinctly  of  two  lateral  portions  united  by  a 
narrow  triangular  slip  of  aponeurosis.  Each 
portion  is  connected  inferiorly  to  the  integu- 
ment of  the  eyebrow  through  the  intervention 
of  cellular  membrane,  and  slightly  overlapped 
by  the  superior  fibres  of  the  orbicular  muscle  of 
the  eyelids,  and  commingled  with  some  of  the 

3  c  2 


REGIONS  AND  MUSCLES  OF  THE  CtiANIUM. 


fibres  of  the  last  named  muscle,  as  well  as  of 
the  corrugator  supercilii.  The  apoueurotic 
slip  before  alluded  to,  situated  in  the  middle 
line,  forms  the  internal  boundary  of  each  la- 
teral portion.  On  the  outside  the  fibres  gra- 
dually shorten  and  extend  a  very  short  distance 
into  the  temporal  region,  over  the  temporal 
fascia.  Each  portion  presents  a  convex  margin 
above,  which  is  inserted  into  the  thin  tendinous 
aponeurosis,  which  extends  over  the  middle 
portion  of  the  occipito-frontal  region,  correspond- 
ing to  the  posterior  margin  of  the  frontal  bone, 
the  fronto-parietal  suture,  internal  portions  of 
the  parietal  bones,  the  sagittal  and  lambdoidal 
sutures  and  part  of  the  occipital  bones,  but  se- 
parated froin  them  by  the  pericranium  and  by 
some  fine  cellular  tissue  which  connected  the 
aponeurosis  to  the  last-named  membrane.  This 
aponeurosis  is  called  the  cranial  or  epicranial 
aponeurosis  :  in  some  instances  its  fibrous  cha- 
racter is  very  distinct  in  all  its  extent ;  but  very 
frequently  it  is  most  manifest  in  its  posterior 
third  or  half,  the  anterior  part  being  little  more 
than  condensed  cellular  membrane,  excepting 
near  to  the  fleshy  fibres  of  the  frontal  portion  of 
the  muscles,  where  the  aponeurotic  structure 
again  becomes  manifest.  On  the  sides  this 
aponeurosis  gradually  degenerates  into  cellular 
membrane  without  leaving  any  defined  margin. 
The  aponeurosis  in  its  whole  extent  adheres 
closely  to  the  superjacent  subcutaneous  cellular 
tissue  and  to  the  subjacent  pericranium  through 
the  intervention  of  a  fine  cellular  membrane 
already  referred  to.  Proceeding  from  before 
backwards,  we  find  that  this  aponeurosis  ends 
in  affording  insertion  to  the  fibres  which  form 
the  posterior  belly  of  the  muscle. 

This  portion  of  the  muscle,  also  called  the 
occipital  muscle,  consists  likewise  of  two  lateral 
portions  which  are  attached  inferiorly  to  the  ex- 
ternal part  of  the  superior  curved  line  of  the 
occipital  bone,  and  to  the  mastoid  portion  of 
the  temporal.  The  fibres  are  parallel  and 
nearly  vertical,  inclining  a  little  inwards,  and 
are  inserted,  as  already  described,  into  the  pos- 
terior margin  ot  the  epicranial  aponeurosis. 
The  attachment  of  the  muscle  to  the  occipital 
bone  is  immediately  above  that  of  the  sterno- 
mastoid  and  splenius  muscles.  On  the  sides 
the  fibres  gradually  disappear  over  the  mastoid 
portion  of  the  temporal  bone,  and  the  fleshy 
belly  of  the  muscle  lies  immediately  over  the 
pericranium,  some  cellular  membrane  only  in- 
tervening; its  adhesion  to  the  skin,  however,  is 
less  intimate  than  that  of  the  frontal  portion. 

This  muscle  is  evidently  destined  to  act  upon 
the  integuments  of  the  cranium  :  its  influence 
is  most  apparent  upon  the  skin  of  the  forehead 
and  eyebrows ;  it  distinctly  raises  the  latter, 
and  throws  the  former  into  transverse  wrinkles. 
Under  its  influence  the  whole  scalp  may  be 
made  to  move  backwards  and  forwards,  but  the 
occipital  portion  of  the  muscle  cannot  create,  as 
the  frontal  does,  wrinkles  in  its  corresponding 
integument,  owing  to  the  less  firm  adhesion  of 
the  muscle  to  it. 

Subjacent  to  the  anterior  portion  of  the  occi- 
pito-frontal is  is  the  corriigulor  supercilii  muscle, 
jit  lies  on  the  inner  half  or  third  of  the  orbital 


margin  of  the  frontal  bone.  By  its  inner  extre- 
mity it  is  attached  to  the  internal  angular  pro- 
cess of  the  frontal  bone ;  the  fibres  pass  thence 
outwards,  inclining  a  little  upwards,  and  are 
inserted  into  the  integument  of  the  eyebrow, 
being  mixed  with  the  orbicularis  and  occipito- 
frontalis  muscle.  This  muscle  evidently  can 
depress  the  eyebrow,  and  acting  in  conjunction 
with  its  fellow,  throw  the  integuments  into 
vertical  wrinkles,  approximating  the  eyebrows, 
and  occasioning  the  act  of  frowning.  This 
muscle  lies  on  the  supra-orbital  nerve  and 
vessels. 

4.  Nerves. — The  anterior  part  of  the  occi- 
pito-frontal region  is  freely  supplied  with  nerves 
from  those  branches  of  the  ophthalmic  portion 
of  the  fifth  which  originate  within  the  orbit.    Of 
these  the  supra-orbital  is  the  largest:  imme- 
diately after  its  emergence  from  the  supra-or- 
bital foramen  this  nerve  divides  into  a  series  of 
branches  which  pass  up  on  the  forehead,  some 
adhering  to  the  pericranium,  others  distributed 
to  the  muscle,  and   others  becoming  subcu- 
taneous.    Here,  too,  we  find  ramifications  of 
the  supra- trochleator  or  internal  frontal  nerve, 
chiefly  distributed  in  the  internal  portion  of  the 
muscle.     At  the  external  part  of  this  frontal 
region  we  find   some  filaments  of  the  portio 
dura.     In  the  posterior  or  occipital  region  the 
principal  nerves  are  derived  from  the  cervical 
plexus;  the  auricular  and  mastoid  branches  of 
this  plexus  distribute  their  filaments  here;  and 
we  also  find  ramifications  from  the  posterior 
branch  of  the  first  cervical  nerve,  accompany- 
ing the  subdivisions  of  the  occipital  artery. 

5.  Arteries. — In  front  we  have  ramifications 
of  the  supra-orbital  and   superficial  temporal 
freely   anastomosing    with    each    other;    and 
deeper-seated,    a  few  branches  .  of   the  deep 
temporal,  distributed  to  the  pericranium.     In 
the   occipital  region  we    have   the   occipital, 
often  of  considerable  size,   and  the  posterior 
auricular  also  sends  some  of  its  ramifications 
to   anastomose  with    the    occipital    branches. 
Both  in  front  and  behind,  the  arteries  of  oppo 
site  sides  inosculate  with  each  other  on  the 
middle  line. 

6.  Veins. — Small  veins  accompany  most  of 
the  arteries ;  but  the  most  remarkable  vein  is 
one  which   is  situated   in   the   frontal  region 
nearly  on  the  middle  line ;   it  is  the  frontal 
vein,  or  vena  preparata,   sometimes  replaced 
by  two  or  three.     Velpeau  advocates  the  re- 
vival of  the  ancient  practice  of  bleeding  from 
this  vein  in  head   affections.      It  carries  the 
blood,  as  he  observes,  from  all  the  anterior  part 
of  the  head  to  the  root  of  the  nose,  whence  he 
argues  that  venesection  practised  on  this  vessel 
would  empty  the  whole  of  the  scalp.     How 
often  in  practice  do  we  see  manifest  advantage 
from   cupping  the  temples  or  some  region  of 
the  scalp,  when  little  or  no  benefit  had  been 
derived   from  other  modes  of  practising  the 
detraction  of  blood  ! 

7.  Lymphatics. — The   lymphatics   are   very 
few,  and  pass  into  the  parotid  ganglions,  or 
those  behind  the  ear  or  in  the  superior  part  of 
the  neck. 

8.  Pericranium. — This  fibrous  tissue,  pos- 


REGIONS  AND  MUSCLES  OF  THE  CRANIUM. 


sessing  the  same  properties  as  the  periosteum 
in  other  parts  of  the  body,  is,  in  a  practical 
point  of  view,  not  the  least  interesting  structure 
which  is  to  be  found  in  this  region.  It  is 
largely  supplied  with  blood,  more  especially 
in  early  life.  We  have  already  noticed  its 
adhesion  to  the  superjacent  aponeurosis ;  it 
adheres  to  the  bone  by  cellular  membrane,  and 
is  easily  raised  from  it  by  dissection  in  all 
points  except  where  there  are  sutures.  This 
membrane  is  not  (infrequently  the  seat  of  peri- 
ostitis and  of  nodes. 

II.  Temporo-parietal  region. — The  lateral 
boundary  of  the  occipito-frontal  region  consti- 
tutes the  superior  limit  of  this  region,  and  a 
line  drawn  from  the  external  angular  process  of 
the  os  frontis  backwards  and  a  little  down- 
wards along  the  zygoma  to  the  mastoid  process 
of  the  temporal  bone,  limits  it  inferiorly. 

The  integument  and  subcutaneous  cellular 
membrane  of  this  region  differ  but  little  from 
the  same  structures  in  the  occipito-frontal  re- 
gion. The  former  is  finer  and  not  so  thick  as 
in  the  middle  and  posterior  parts  of  the  last- 
named  region.  The  hairs  are  oblique,  some 
directed  forwards,  others  backwards  towards 
the  occiput,  and  others  downwards  overlap- 
ping the  ears.  Here  the  hairs  first  begin  to 
grow  grey,  whence  the  denomination  tempora 
has  been  applied  to  these  regions,  grey  hairs 
marking  the  inroads  of  time.  The  skin  of  this 
region,  however,  is  naturally  bald  for  a  consi- 
derable portion  in  front  of  the  ear,  and  for  the 
distance  of  about  an  inch  immediately  behind 
and  above  it. 

The  subcutaneous  cellular  tissue  is  very 
loose  in  front  of  the  ear,  but  behind  it  in  the 
vicinity  of  the  mastoid  process,  it  is  more 
dense,  and  hence  the  scalp  is  much  less  move- 
able  over  that  process,  and  immediately  be- 
hind the  ear.  The  epicranial  aponeurosis  is 
confounded  with  this  subcutaneous  tissue  in 
the  superior  part  of  this  region. 

Temporal  fascia. — Subjacent  to  the  cellular 
expansion  is  a  fibrous  membrane  of  consider- 
able strength,  which  stretches  from  the  zygoma 
below  to  the  curved  line  above  and  behind 
which  limits  the  temporal  fossa  on  the  frontal, 
parietal,  and  temporal  bones.  It  is  very  thick 
and  strong,  composed  of  white  interlacing  fi- 
bres, firmly  attached  to  the  points  of  bone 
referred  to,  and  giving  attachment  by  the 
greater  part  of  its  deep  surface  to  the  fibres  of 
the  temporal  muscle.  In  front  and  below, 
however,  for  a  short  space,  some  adipose  cel- 
lular membrane  intervenes  between  the  muscle 
and  the  fascia.  Along  the  margin  of  the  zy- 
goma, especially  in  front,  the  fascia  is  divisible 
into  two  laminae,  which  pass  down,  one  in- 
ternal, the  other  external  to  the  bone,  and 
become  incorporated  with  periosteum :  by  their 
separation  above  the  zygoma  they  leave  a  tri- 
angular space  which  is  in  general  filled  with 
cellular  tissue  more  or  less  adipose. 

Muscles. — Some  fibres  of  the  occipito- 
frontal  is  extend  more  or  less  into  this  region, 
according  to  the  state  of  developement  of  the 
muscle.  Here  too  we  find  the  three  auricular 
muscles  immediately  subjacent  to  the  subcu- 


749 

taneous  cellular  tissue.  (See  EAR.)  Under  the 
temporal  fascia  and  adhering  to  its  deep  surface 
is  the  fleshy  portion  of  the  temporal  muscle, 
attached  to  almost  the  whole  of  the  fossa. 
Behind,  the  mastoid  process  is  enveloped  by 
the  tendinous  insertion  of  the  sterno-mastoid 
muscle. 

Nerves. — The  nerves  of  this  region  are  very 
numerous.  The  subcutaneous  ones  are  derived 
from  the  portio  dura  and  the  superficial  tem- 
poral or  auricular  of  the  fifth,  and  posteriorly 
from  the  raastoid  and  digastric  branches  of  the 
portio  dura,  as  well  as  some  from  the  ascending 
branches  of  the  cervical  plexus.  The  deep- 
seated  nerves  in  the  temporal  fossa  are  the  deep 
temporals  from  the  inferior  maxillary,  and  the 
temporal  filament  of  the  orbitar  branch  of  the 
superior  maxillary. 

Arteries. — The  superficial  arteries  are  nu- 
merous and  important.  They  are  derived  from 
the  trunk  of  the  superficial  temporal,  which 
enters  this  region  by  passing  over  the  zygoma 
in  front  of  the  tragus,  crossed  over  by  the 
anterior  auris  muscle.  After  it  has  passed  the 
zygoma  it  inclines  forwards,  and  is  a  little  more 
distant  from  the  ear  than  when  on  the  zygoma. 
In  all  this  course  it  may  be  felt  distinctly, 
although  it  is  pretty  firmly  bound  down  by  the 
subcutaneous  tissue  and  epicranial  aponeurosis, 
which  are  here  conjoined.  A  little  more  than  an 
inch  above  the  zygoma  it  divides,  and  we  trace 
its  anterior  branch  forwards  towards  the  frontal 
region,  which  it  enters  and  anastomoses  with 
the  supra-orbitaL  The  posterior  branch  passes 
upwards  and  backwards,  winding  over  the  ear, 
and  anastomoses  with  ramifications  from  the 
occipital  artery.  It  is  in  one  or  other  of  these 
branches  that  arteriotomy  is  generally  performed, 
in  preference  to  opening  the  trunk  of  the  artery. 
The  middle  branch  of  the  temporal  artery  pierces 
the  fascia,  and  enters  the  substance  of  the  tem- 
poral muscle,  anastomosing  with  the  deep 
temporals.  The  posterior  part  of  this  region  is 
supplied  from  branches  of  the  occipital  and 
posterior  auris. 

Veins. — Veins  accompany  almost  all  the 
arteries :  there  are  none  worthy  of  any  special 
notice. 

Lymphatics. — These  vessels  likewise  accom- 
pany the  arteries,  and  enter  the  ganglions  in 
the  neighbourhood  of  the  ear,  and  those  of  the 
neck. 

Pericranium. — The  pericranium  does  not 
differ  from  that  of  the  occipito-frontal  region, 
except  perhaps  in  firmer  adhesion  to  the  squa- 
mous  portion  of  the  temporal  bone.  It 
affords  insertion  to  the  fibres  of  the  temporal 
muscle.  This  region  presents  more  surgical 
interest  than  the  former  one;  it  is  more  fre- 
quently the  seat  of  operation  (arteriotomy,  and 
in  its  posterior  part,  that  of  opening  the  mastoid 
cells);  and  in  consequence  of  the  number  of  its 
arteries  and  nerves,  and  the  great  strength  of 
the  temporal  fascia,  wounds  in  this  region  are 
of  a  more  dangerous  kind.  Fractures  here  are 
also  liable  to  be  complicated  with  a  wound  of 
the  middle  meningeal  artery,  part  of  the  course 
of  which  corresponds  to  this  region. 

(R.  B.  Todd.) 


750 


CRUSTACEA. 


CRUSTACEA.  Eng.  Crustaceans;  Germ. 
Krustenthiere ;  Fr.  Crustaces — This  is  the 
name  given  to  a  class  of  articulated  animals, 
the  type  of  which  we  have  in  the  common  crab 
and  lobster,  and  which  is  essentially  distin- 
guished by  the  conformation  of  the  organs  of 
circulation,  of  respiration,  and  of  locomotion. 

The  body  of  these  animals  is  articulated; 
that  is  to  say,  it  is  divided  into  rings,  for  the 
most  part  very  distinct  and  partially  move- 
able;  their  integuments  are  of  considerable 
consistency,  being  either  horny  or  calcareous, 
and  form  a  kind  of  external  skeleton;  their 
extremities  are  also  articulated,  arranged  in  a 
double  series,  and  constitute  antennae,  jaws, 
limbs,  (ambulatory,  natatory,  or  prehensile,  the 
most  common  number  of  which  is  five  or  seven 
pairs,)  and  other  appendages ;  their  nervous 
system  is  ganglionic,  situated  partly  in  front  of 
the  alimentary  canal,  and  partly  behind  and 
below  the  intestine ;  their  blood  is  colourless, 
and  put  into  motion  by  an  aortic  and  dorsal 
heart;  their  respiration  is  almost  invariably 
aquatic,  and  is  accomplished  by  means  of 
branchiae,  or  the  skin  only;  to  conclude,  the 
sexes  are  distinct,  and  the  organs  of  genera- 
tion double. 

Great  and  striking  analogies  occur  between 
the  Crustacea,  the  Insecta,  and  the  Arachnida; 
so  that  it  was  long  the  custom  to  associate  the 
whole  of  the  animals  now  comprised  in  these 
three  classes,  under  the  single  name  of  IN- 
SECTA, or  Insects.  Brisson  and  Lefranc 
de  Berk  hey  proposed,  it  is  true,  to  separate 
the  Crustacea,  but  the  classifications  of  these 
writers  not  being  based  upon  organic  charac- 
ters of  sufficient  consequence,  did  not  receive 
the  general  assent  of  naturalists,  and  it  is  only 
since  the  beginning  of  the  present  century  that 
the  necessity  of  separating  the  annulosa  into 
certain  distinct  classes  has  been  universally 
acknowledged.  This  result  was  mainly  due 
to  the  anatomical  inquiries  of  Cuvier,  and 
this  great  naturalist  was  even  the  first  who 
established  a  class  among  the  invertebrate 
series  of  animals  for  the  reception  of  those 
having  bloodvessels,  a  ganglionic  spinal  cord, 
and  articulated  extremities,  characters  which, 
at  the  present  time,  still  suffice  to  distinguish 
the  Crustacea  from  the  greater  number  of  other 
animals. 

It  is  more  especially  in  the  general  confor- 
mation of  the  body,  in  the  structure  of  the 


extremities,  and  in  the  organization  of  the  ner- 
vous system,  that  the  Crustacea  resemble  the 
Insects  and  Arachnidans.  The  apparatus  of 
vegetative  life  in  these  different  animals  pre- 
sents numerous  and  important  differences.  Thus 
Insects,  instead  of  breathing  by  means  of  bran- 
chiae, and  possessing  a  vascular  system  like  the 
Crustacea,  breathe  by  means  of  tracheae,  and 
have  no  bloodvessels ;  and  Arachnidans,  which, 
like  the  Crustacea,  have  a  heart  more  or  less 
perfect,  and  distinct  vessels  for  the  circulation 
of  their  blood,  have  an  aerial  respiration  ef- 
fected either  by  the  medium  of  tracheae  or  of 
pulmonary  sacs. 

The  whole  of  the  Crustacea  are  evidently 
formed  after  one  and  the  same  general  type ; 
still,  numerous  and  extensive  varieties  of  struc- 
ture are  observed  among  these  animals;  and 
when  compared  one  with  another,  their  orga- 
nization is  found  to  become  more  and  more 
complicated  in  proportion  as  we  rise  in  the  series 
comprised  by  the  group;  it  is  farther  found 
that  the  lower  links  of  this  kind  of  chain  re- 
present, to  a  certain  extent,  the  different  phases 
through  which  the  more  perfect  Crustaceans 
pass  during  the  period  of  their  embryonic  ex- 
istence. 

This  diversity  of  organization  affords  the 
grounds  by  which  naturalists  are  guided  in 
their  distribution  of  the  Crustaceans  into  orders 
and  families. 

The  natural  arrangements  of  these  animals 
that  have  been  followed,  are  consequently  ob- 
served to  vary  with  the  extent  of  knowledge  of 
their  structure  possessed.  It  were  tedious  to 
enter  upon  the  consideration  of  the  different  sys- 
tems which  have  been  successively  proposed  for 
their  classification ;  in  order  to  aid  the  mind  in 
the  comprehension  of  the  anatomical  details 
into  which  we  shall  have  to  enter  in  the  course 
of  this  article,  it  will  be  enough  for  us  to  pre- 
sent at  once  those  divisions  which  appear  to 
indicate  most  truly  the  differences  and  resem- 
blances subsisting  between  the  various  mem- 
bers of  the  class  ;*  and  to  do  this  in  the  most 
compendious  manner,  and  to  exhibit  the  clas- 
sification which  thence  ensues,  we  shall  present 
them  to  the  reader  in  the  shape  of  a  synoptical 
table. 


*  See  Histoire  Naturelle  des  Crustaces,   par  M. 
Milne  Edwards,  vol.  i.  p.  231. 


CRUSTACEA. 


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CRUSTACEA. 


§  1 .  Of  the  skin  or  tegument ary  skeleton,  and 
of  the  organs  of  locomotion. 

In  the  definition  which  has  been  given  of 
the  Crustacea,  one  of  the  most  important  cha- 
racters was  derived  from  the  nature  and  dispo- 
sition of  their  tegumentaiy  system.  And  it  is 
from  this  point  that  we  shall  start  in  laying 
before  our  readers  a  detailed  account  of  the 
peculiarities  of  organization  presented  by  this 
class  of  animals.  By  pursuing  this  course  all 
the  subsequent  parts  of  the  present  article  will 
appear  clearer,  the  disposition  of  the  internal 
organs,  their  forms,  their  mutual  relations,  &c. 
being  in  a  great,  number  of  instances  readily 
explicable  by  the  various  modes  of  confor- 
mation of  the  modified  skin,  which  in  this 
class  performs  the  important  office  of  the  in- 
ternal skeleton  among  the  Vertebrata. 

In  some  Crustacea  the  skin  always  con- 
tinues soft,  but  in  the  greater  number  it 
presents  a  great  degree  of  solidity,  and  forms 
a  solid  casing,  within  which  are  included 
the  whole  of  the  soft  parts.  This  difference 
in  the  condition  of  the  tegumentary  envelope 
is  generally  found  to  coincide  with  the  pre- 
sence or  absence  of  particular  organs  for  the 
purposes  of  respiration ;  and  in  fact  it  is  easy 
to  understand  that  in  those  species  in  which 
this  important  function  is  performed  by  the 
surface  of  the  body  at  large,  the  integument 
required  to  be  membranous,  whilst  in  those  in 
which  the  covering  is  of  stony  hardness,  a  con- 
dition which  renders  it  incompetent  to  expose 
the  blood  to  the  contact  of  the  atmospheric 
air  dissolved  in  water,  respiration  can  only  be 
performed  by  the  medium  of  organs  especially 
contrived  and  set  apart  for  the  purpose. 

When  the  tegumentary  envelope  of  the  Crus- 
tacea is  studied  among  the  more  elevated  indi- 
viduals of  the  class,  it  is  found  to  possess  a 
somewhat  complex  structure;  parts  may  be 
distinguished  in  it  comparable  to  those  which 
are  known  to  constitute  the  integument  of  the 
Vertebrata.  Among  the  Brachyura,  for  in- 
stance, the  integument  consists  of  a  corium 
and  an  epidirmis  with  a  pigmentary  matter  of 
a  peculiar  nature  destined  to  communicate  to 
the  latter  membrane  the  various  colours  with 
which  it  is  ornamented. 

The  corium  or  dermis,  as  among  the  Verte- 
brata, is  a  thick,  spongy,  and  very  vascular  mem- 
brane; on  its  inner  surface  it  is  intimately  con- 
nected with  a  kind  of  serous  membrane,  which 
lines  the  parietes  of  the  cavities  in  the  Crus- 
tacea in  the  same  manner  as  the  serous  mem- 
branes line  the  internal  cavities  among  the  Ver- 
tebrata ;  these  two  membranes,  divided  in  the 
latter  order  by  the  interposition  of  muscular 
and  bony  layers,  which  cover  and  protect  the 
great  cavities,  become  closely  united  when 
these  layers  disappear,  as  they  do  in  the  Crus- 
tacea in  consequence  of  the  important  changes 
that  take  place  in  the  conformation  of  the  ap- 
paratus of  locomotion. 

The  corium,  again,  among  the  Crustacea,  is 
completely  covered  on  its  outer  surface  by  a 
membranous  envelope  unfurnished  with  blood- 
vessels, and  which  must  be  held  in  all  respects 
as  analogous  to  the  epidermis  of  the  higher 


animals.  It  is  never  found  in  the  properly 
membranous  state,  save  at  the  time  of  the  Crus- 
tacea casting  their  shell;  at  this  period  it  is 
interposed  between  the  corium  and  the  solid 
covering,  ready  to  be  cast  off,  and  has  the 
appearance  of  a  pretty  dense  and  consistent 
membrane,  in  spite  of  its  thinness.  It  forms, 
as  among  animals  higher  in  the  scale,  a  kind  of 
inorganic  lamina,  applied  to  the  surface  of  the 
corium,  from  which  it  is  an  exudation.  After 
the  fall  of  the  old  shell,  it  becomes  thicker  and 
very  considerably  firmer,  owing  to  the  deposi- 
tion or  penetration  of  calcareous  molecules 
within  its  substance,  as  well  as  by  the  addition 
of  new  layers  to  its  inner  surface.  The  degree 
of  hardness  finally  acquired,  however,  and  the 
amount  of  calcareous  matter  deposited  within 
it,  vary  considerably;  in  many  members  of  the 
class  it  remains  semi-corneous,  in  a  condition 
very  similar  to  that  of  the  integuments  of  in- 
sects, with  which,  moreover,  it  corresponds 
very  closely  in  point  of  chemical  composition ; 
in  the  higher  Crustaceans,  again,  its  composi- 
tion is  very  different:  thus,  whilst  chitine  in 
combination  with  albumen  is  the  principal 
element  in  the  tegumentary  skeleton  of  some 
species,  this  substance  scarcely  occurs  in  the 
proportion  of  one  or  two-tenths  in  the  carapace 
of  the  Decapods,  which,  on  the  contrary,  con- 
tains sixty  and  even  eighty  per  cent,  of  phos- 
phate and  carbonate  of  lime,  the  latter  sub- 
stance particularly  occurring  in  considerably 
larger  proportions  than  the  former.* 

With  regard  to  the  pigmentum,  it  is  less  a 
membrane  or  reticulation  than  an  amorphous 
matter  diffused  through  the  outermost  layer  of 
the  superficial  membrane,  being  secreted  like 
this  by  the  corium.  Alcohol,  ether,  the  acids, 
and  water  at212°Fahr.  change  it  to  a  red  in 
the  greater  number  of  species;  but  there  are 
some  species  in  which  it  may  be  exposed  to  the 
action  of  these  different  agents  without  under- 
going any  perceptible  change.f 

The  epidermic  layer  hardened  in  different 
degrees  is  the  part  which  mainly  constitutes 
the  tegwnentary  skeleton  of  the  Crustacea.  In 
its  nature  it  is  obviously  altogether  different 
from  that  of  the  internal  skeleton  of  the  Verte- 
brata ;  still  its  functions  are  the  same,  and  this 
physiological  resemblance  has  led  naturalists  to 
speak  of  these  two  pieces  of  organic  mecha- 
nism, so  dissimilar  in  their  anatomical  rela- 
tions, under  the  common  name  of  skeleton. 

The  tegumentary  skeleton  of  the  Crustacea 
consists,  like  the  bony  skeleton  of  the  Verte- 
brata, of  a  great  number  of  distinct  pieces, 
connected  together  by  means  of  portions  of  the 
epidermic  envelope  which  have  not  become 
hardened,  in  the  same  way  as  among  the 
higher  animals  certain  bones  are  connected  by 
cartilages,  the  ossification  of  which  is  only 
accomplished  in  extreme  old  age.  On  the 
varieties  which  these  pieces  present  in  their 


*  Chevreul  and  Geoffrey,  Journal  Complemen- 
taire  du  Diction,  des  Sciences  Medicales,  Avril 
1820.  Milne  Edwards,  Hist.  Nat.  des  Crustaccs, 
t.  i.  p.  10. 

t  Lassaigne,  Journal  d.  Pharmacie,  t.  vi.  p.  174. 


CRUSTACEA. 


753 


number,  their  form,  their  relations,  &c.  depend 
the  differences  that  occur  in  the  conformation 
of  the  solid  frame-work,  the  anatomical  study 
of  which  is  now  about  to  engage  our  atten- 
tion. 

The  most  prominent  feature  in  the  external 
skeleton  of  the  Crustacea  is  common  to  the 
whole  grand  division  of  articulated  animals,  and 
consists  in  the  division  of  this  envelope  into  a 
series  of  segments  or  rings,  connected  in  suc- 
cession one  with  another,  and  supporting  tu- 
bular appendages,  also  divided  into  segments, 
and  arranged  endwise.  This  peculiar  structure 
is  met  with  among  the  whole  of  the  Crustacea; 
but  when  the  frame-work  of  these  animals  is 
examined  more  narrowly,  variations  are  disco- 
vered so  extensive  and  so  numerous,  that  the 
mind  is  almost  led  to  regard  it  as  consisting  of 
elements  essentially  different.  Yet  this  is  not 
so;  and  in  pursuing  the  study,  aided  by  the 
means  of  investigation  developed  in  the  pro- 
gress of  the  philosophy  of  the  natural  sciences, 
very  opposite  results  are  elicited, — results  which 
are  replete  with  interest  and  instruction  in 
regard  to  the  mysteries  of  nature  in  her  creative 
energies. 

Now  these  methods  of  investigation  may  be 
reduced  to  two : — the  first,  which  studies  crea- 
tures at  their  full  growth,  after  having  ar- 
ranged them  according  to  the  natural  order 
which  follows  from  the  investigation  of  their 
organization  :  the  second,  which  studies  each 
creature,  but  the  more  perfect  in  preference,  in 
the  series  of  successive  evolutions  which 
constitute  the  different  phases  of  the  em- 
bryonic state  and  of  extra-uterine  life  ;  for  it 
is  a  demonstrated  fact  that  these  two  series, 
so  distinct,  so  widely  separated  in  appearance, 
are  in  reality  connected  by  links  so  inti- 
mate, that  the  one  is,  in  certain  respects,  the 
permanent  reproduction  of  the  other,  which  is 
the  continual  repetition  of  the  first  in  one  and 
the  same  individual. 

By  studying  in  this  relative  or  comparative 
manner  the  skeleton  of  the  Crustacea,  we  suc- 
ceed in  reducing  to  common  principles  the 
mode  of  conformation,  apparently  so  various, 
of  this  apparatus,  in  the  different  groups  formed 
by  these  animals.  A  remarkable  tendency  to 
uniformity  of  composition  is  every  where  re- 
cognizable, and  all  the  varieties  are  explicable 
in  a  general  way  by  the  laws  in  conformity  with 
which  the  development  of  these  animals  takes 
place. 

During  the  period  of  embryonic  life  the  body 
is  seen  becoming  divided  into  rings  more  and 
more  numerous,  and  more  and  more  unlike 
one  another.  The  same  tendency  to  diversity 
in  the  organization  is  also  found  in  the  types  of 
which  the  series  of  Crustaceans  consists;  and  in 
both  instances  the  differences  are  readily  seen  to 
depend  on  various  modifications  undergone  by 
parts  originally  similar.  It  is  farther  referable 
to  one  of  the  most  general  laws  of  organiza- 
tion, viz.  the  tendency  which  nature  shows  to 
perfect  functions  by  subdividing  the  work  to  be 
done,  and  throwing  it  upon  a  greater  number  of 
special  organs.  And  we  observe,  in  fact,  among 
the  most  inferior  animals  that  the  different  seg- 


ments into  which  the  body  is  divided  are  so 
completely  repetitions  of  one  another,  that 
they  all  act  precisely  in  the  same  manner; 
they  severally  include  the  elements  necessary 
to  the  display  of  the  vitality  distinctive  of  the 
entire  system  to  which  they  belong,  so  that 
they  may  be  dissevered  without  any  function 
whatsoever  being  therefore  the  less  completely 
performed  in  either  of  the  detached  portions. 
Many  Annelidans  present  instances  of  this 
uniformity  of  composition.  As  we  rise,  how- 
ever, in  the  scale  of  beings,  the  different  seg- 
ments of  the  body  are  found  to  become  more 
and  more  unlike,  both  as  regards  their  func- 
tions and  their  conformation. 

This  law  is  also  visibly  manifested  among  the 
Crustaceans,  whether  they  be  studied  at  the 
various  epochs  of  their  embryonic  state  or 
compared  together,  examples  being  selected 
from  the  different  groups  of  which  this  portion 
of  the  animal  series  consists.  In  either  case  a 
well-marked  tendency  to  subdivision  of  the 
physiological  operations  is  conspicuous;  and 
in  proportion  as  the  divers  acts,  the  aggregate 
of  which  constitutes  the  life  of  the  individual, 
become  attached  to  a  particular  system  or 
place,  the  parts  to  which  different  functions 
are  apportioned,  acquire  forms  more  dissimilar 
and  more  appropriate  to  their  peculiar  uses. 
When  we  come  to  treat  of  the  evolution  of  the 
embryo  of  the  Crustacea,  we  shall  have  occa- 
sion to  revert  to  this  subject,  but  it  is  neces- 
sary so  far  to  hint  at  it  in  this  place,  inasmuch 
as  the  conclusions  which  have  been  mentioned 
will  often  supply  us  with  means  of  explaining 
those  difficulties  that  are  encountered  when  we 
seek  to  render  comparative  the  study  of  the 
different  constituent  parts  of  the  external  ske- 
leton of  the  articulated  series  of  animals. 

The  frame-work  or  solid  parts  of  the  Crus- 
tacea consist,  as  we  have  said,  of  a  series  of 
rings. 

The  number  of  these  rings  may  vary,  but 
this  happens  to  a  much  less  extent  than  on  a 
superficial  view  we  might  be  led  to  conclude. 
By  calling  in  to  our  aid  the  principles  of  ob- 
servation and  of  comparison  pointed  out  above, 
we  have  found  that  in  every  member  of  this 
class  of  animals  the  normal  number  of  seg- 
ments of  the  body  is  twenty-one.  But 
a  very  few  instances  of  a  larger  number  oc- 
curring are  known,  and  it  seldom  happens 
that  the  number  falls  short  of  that  which  has 
been  indicated.  Occasionally,  it  is  true,  one 
or  more  rings  prove  abortive,  and  are  never 
developed  ;  but  in  general  their  apparent  ab- 
sence depends  entirely  on  their  intimate  union 
one  with  another,  and  other  obvious  indica- 
tions of  their  existence  may  be  discovered. 
By-and-by  we  shall  find  that  in  the  embryo 
these  segments  are  formed  in  succession  from 
before  backwards,  so  that,  when  their  evolution 
is  checked,  the  later  rather  than  the  earlier 
rings  are  those  that  are  wanting ;  and  in  fact  it 
is  generally  easy  to  see  in  those  specimens  of 
full-grown  crustaceous  animals  whose  bodies 
present  fewer  than  twenty  segments,  that  the 
anomaly  depends  on  the  absence  of  a  certain 
number  of  the  most  posterior  rings  of  the  body. 


754 


CRUSTACEA. 


The  Loemodipods,  the  Entomostraca,  and  the 
Haustellate  Crustacea  present  us  with  instances 
of  this  condition,  which  calls  to  mind  one  of 
the  stages  through  which  the  embryo  of  the 
higher  species,  whose  development  is  the  most 
complete,  is  known  to  pass. 

Each  segment  of  the  body,  when  it  attains  its 
normal  condition,  consists  of  two  distinct  ele- 
ments :  the  central  or  annular  portion,  and  cer- 
tain appendices  which  it  supports. 

The  central  or  annular  portion  of  the  seg- 
ments of  the  tegumentary  skeleton  presents,  in 
its  most  simple  state,  the  appearance  of  a  com- 
plete ring,  but  instead  of  a  single  piece  it  is 
requisite  to  count  in  its  composition  no  fewer 
than  eight,  as  has  been  demonstrated  by  the 
inquiries  of  M.  Audouin  on  the  structure  of  the 
thorax  of  insects,*  inquiries  the  results  of  which 
are  immediately  and  almost  wholly  applicable 
to  the  Crustacea  so  nearly  allied  to  the  insects 
in  their  organization.  Each  rjng  is  divided 
first  into  two  arcs,  the  one  superior  or  dorsal, 
the  other  inferior  or  ventral,  and  each  arc  may 
present  as  many  as  four  elementary  pieces. 
Two  of  these  pieces  by  being  united  in  the  me- 

Fig.  378. 
t     t 


Theoretical  figure  illustrating  the  composition  of  the 

tegumentary  skeleton  of  Crustacea. 
D,  Dorsal  arc ;  t,  t,  tergal  pieces  ;  e,  e,  epimeral 
pieces  ;   V,  ventral  arc  ;  s,  s,  sternal  and  episternal 
pieces  ;  P,  insertion  of  the  extremities. 

dian  line  constitute  the  tergum  (fg.  378,  D)  ; 
the  superior  arc  is  completed  on  either  side  by 
two  other  pieces,  known  under  the  name  ofjlancs 
or  epimeral  pieces  (Jig.  378,  e}.  The  inferior 
arc  presents  in  its  composition  an  exact  counter- 
part of  the  superior.  Two  of  the  four  pieces 
into  which  it  may  be  resolved  constitute  the 
sternum,  situated  in  the  median  line,  and  are 
flanked  by  the  two  cpisternums.  The  two  arcs 
thus  composed,  instead  of  cohering  by  their 
edges,  leave  a  space  for  the  insertion  of  the 
lateral  appendages  or  extremities  which  corre- 

Fig.  379. 


Anterior  portion  of  the  body  of  an  Amphipoda. 

t,  tergum  of  the  fourth   thoracic  ring  j  e,  epimera 

of  the  same  ring. 

spond  with  them.  It  is  true,  indeed,  that  we 
have  no  instance  of  any  single  ring  which  exhi- 
bits the  whole  of  these  pieces  distinct  from  one 
another ;  in  general  several  are  anchylosed  so 

*  Annales  des  Sc.  Nat.  torn.  i. 


as  to  appear  but  one;  yet  the  comparative 
study  of  the  apparatus  in  the  different  members 
of  the  class  at  large,  leaves  no  doubt  of  their 
existence  severally. 


Fig.  380. 


Thorax  of  an  Atelecyclus  seen  from  below, 
a,  sternal  pieces  of  the  second  thoracic  ring  ;  5, 
episternal  piece  of  the  corresponding  ring ;  c,  epi- 
meral pieces ;  d,  apodemata,  which  run  from  the 
sternum  to  the  epimera,  and  separate  the  inser- 
tions of  the  extremities ;  e,  antipenultimate  ring 
of  the  thorax  presenting  the  orifices  of  the  female 
reproductive  organs. 

It  frequently  happens  that  the  tegumentary 
membrane  is  folded  so  as  to  penetrate  more  or 
less  deeply  the  interior  of  the  ring  among  the 
different  organs  which  fill  the  cavity.  These 
folds,  which  may  become  solid  laminae  by 
being  impregnated  with  calcareous  salts,  have 
received  the  name  of  apodemata,  and  always 
proceed  from  the  lines  of  conjunction  of  the 
different  pieces,  or  of  the  different  rings  with 
one  another.  We  shall  have  occasion  to  revert 
to  this  part  of  our  subject  very  shortly. 

Fig.  381. 


Thorax  of  the  Maja  Squinado,  shewing  the  apode- 
mata which  form  septa  between  the  sternum  and 
the  epimeral  pieces  of  the  thoracic  rings. 

The  structure  of  the  ring  once  investigated 
in  the  manner  we  have  done,  let  us  now  pro- 
ceed to  inquire  in  what  manner  the  different 
rings  by  the  modifications  they  undergo,  and 
by  the  divers  modes  of  union  they  present,  give 
rise  to  the  variety  of  forms  we  observe  among 
the  Crustaceans. 

By  general  consent  and  usage,  three  regions 
are  recognized  in  the  bodies  of  these  animals, — 
a  head,  a  thorax,  and  an  abdomen;  and  from  this 
custom  we  shall  not  depart,  although  we  must 
avow  that  these  denominations  are  only  derived 
from  very  clumsy  views,  and  are  calculated  to 
convey  false  impressions  in  regard  to  the  nature 
and  composition  of  the  parts  so  named,  by 
leading  the  mind  to  liken  them  to  the  grand 
divisions  entitled  head,  thorax,  and  abdomen 
in  the  Vertebrata.  Nevertheless,  with  the  ex- 
ception of  the  objectionable  names,  the  division 
of  the  body  into  three  regions  is  not  less  a  feet 
as  regards  the  organization  of  the  Crustaceans ; 
arid  the  one-and-twenty  rings  of  which,  as  we 
have  said,  their  body  consists  in  the  type  to 
which  every  member  of  the  class  may  be  re- 
ferred, are  generally  found  divided  into  three 


CRUSTACEA. 


755 


Talitra  Saltator  magnified. 

a,  head;  b,  thorax  composed  of  seven  distinct 
rings  ;  c,  abdomen  composed  also  of  seven  dis- 
tinct rings. 

equal  series  of  seven,  each  of  which  may  be 
held  as  corresponding  with  one  of  the  three 
regions.  This  law  of  composition  is  observed 
to  obtain  not  only  among  the  more  simple 
species,  where  the  rings  generally  resem- 
ble each  other  most  closely,  but  its  influence 
may  be  remarked  among  the  most  complicated 
also,  and  amidst  exceptions  and  contradictions 
in  appearance  the  most  obvious.  The  head  or 
cephalic  region  includes  the  principal  organs 
of  sense  as  among  the  Vertebrata,  the  com- 
mencement of  the  apparatus  subservient  to 
digestion,  and  the  appendages  destined  to  seize 
and  masticate  the  food.  The  thorax,  strictly 
speaking,  forms  no  cavity  distinct  from  the  pre- 
ceding, but  is  its  continuation ;  the  part  espe- 
cially designated  thorax,  however,  is  that  which 
is  included  from  front  to  back  between  the 
head  and  the  beginning  of  the  abdomen,  and  is 
formed  by  the  rings  to  which  the  extremities 
serving  for  locomotion  are  attached.  This  mid- 
dle portion  of  the  general  cavity  of  the  body 
contains  almost  the  whole  of  the  viscera.  As 
to  the  abdomen,  it  succeeds  the  last  of  the 
thoracic  rings,  distinguishable  by  the  presence 
in  it  of  the  orifices  of  the  male  organs  of  gene- 
ration ;  the  appendices  attached  to  it  do  not 
commonly  attain  any  considerable  size,  and  do 
not  serve  in  a  general  way  as  organs  of  locomo- 
tion ;  to  conclude,  nothing  is  found  in  its  inte- 
rior save  muscles  and  the  terminal  portion  of  the 
intestinal  canal,  the  anal  orifice  of  which  exists 
in  the  last  of  the  abdominal  series  of  rings. 

These  three  portions  of  the  tegumentary  ske- 
leton are  not  always  equally  distinct,  and  their 
respective  limits  may  even  vary,  for  we  occa- 
sionally observe  two  or  three  of  the  foremost 
thoracic  rings  detaching  themselves,  as  it  were, 
from  this  region  to  which  they  properly  belong, 
to  join  or  blend  with  the  cephalic  rings ;  and 
the  same  thing  may  be  said  in  regard  to  the 
segments  of  which  each  of  the  remaining  divi- 
sions of  the  body  consists;  we  in  fact  know  of 
no  specimen  of  a  Crustacean  in  which  the  whole 
of  the  rings  are  moveable  upon  one  another ;  a 
certain  number  of  them  always  appear  to  be- 
come consolidated,  and  this  union  is  frequently 
so  intimate  that  all  traces  of  its  existence  are 
obliterated,  so  that  the  section  of  the  body 
which  results  from  this  aggregation  of  rings 
appears  to  consist  of  no  more  than  a  single 


piece,  and  on  a  cursory  view  might  be  held  to 
be  constituted  by  a  simple  ring.  The  shape 
and  size  of  these  compound  rings  varies  also, 
circumstances  which  evidently  depend  on  the 
unequal  development  of  the  different  pieces  of 
which  they  severally  consist. 

This  consolidation  of  the  rings  occurs  with 
increasing  frequency  as  we  rise  in  the  scale  of 
Crustaceans,  and  approach  those  the  organiza- 
tion of  which  is  most  complex ;  yet  there  are  a 
considerable  number  of  species  which  form  ex- 
ceptions to  this  rule.  The  consolidation  of  the 
rings  also  shows  a  tendency  to  take  place  in 
the  same  order  in  which  the  different  segments 
of  the  tegumentary  skeleton  appear  in  the  em- 
bryo, that  is  to  say  from  before  backwards : 
thus  it  is  generally  complete  as  regards  the 
cephalic  rings ;  it  is  more  frequent  as  regards 
the  foremost  than  the  hindmost  thoracic  rings ; 
and  it  but  rarely  occurs  among  the  abdominal 
rings. 

The  differences  which  present  themselves  in 
the  dimensions  and  forms  of  the  different  rings 
of  the  tegumentary  skeleton,  and  which  concur 
so  essentially  in  producing  varieties  in  the  ge- 
neral form  of  the  Crustaceans,  also  show  a  ten- 
dency to  become  greater  and  greater  as  we  as- 
cend in  the  series  of  these  animals,  and  com- 
monly influence  the  cephalic  rings  in  a  degree 
greater  than  those  of  the  divisions  situated 
more  posteriorly. 

To  conclude,  it  is  also  among  the  most  ele- 
vated Crustaceans  that  the  tegumentary  skeleton 
is  complicated  in  the  greatest  degree  by  the 
evolution  of  apodemata  in  the  interior  of  the 
rings ;  and  further,  it  is  in  the  cephalo-thoracic 
portion  of  the  skeleton  only  that  these  lamina; 
are  encountered. 

A  few  examples  will  render  these  general 
rules  more  readily  appreciated. 

In  the  earlier  periods  of  evolution  of  the 
embryo  of  the  river-crab,  the  whole  of  the  rings, 
which  are  even  then  apparent,  are  of  the  same 
focm  and  dimensions,  and  the  segments,  which 
only  appear  at  a  later  date,  are  at  first  similar 
to  what  these  rings  were  in  the  beginning. 
This  state  of  uniformity  in  the  composition 
of  the  whole  of  the  constituent  rings  of  the 
tegumentary  skeleton,  which  is  invariably  tran- 
sient in  the  embryo,  is  not  observed  as  a 
permanent  feature  in  any  perfectly  developed 
Crustacean ;  still  there  are  several  of  these  ani- 
mals which  are  but  little  removed  from  it.  In 
the  Branchipods,  for  instance,  the  body  consists 
of  a  long  series  of  rings,  having,  with  the  ex- 
ception of  the  very  first,  as  nearly  as  possible 
the  same  form  and  the  same  dimensions.  In  the 
Amphipods  (fig.  382)  the  want  of  resemblance 
between  the  different  rings  of  the  body  becomes 
much  more  remarkable:  the  first  seven  become 
so  completely  united  that  they  form  a  single 
piece,  in  which  no  trace  even  of  the  lines  of 
consolidation  remains,  and  the  conical  segment 
which  constitutes  the  head  grows  much  more 
slowly  than  the  rest  of  the  body,  so  that  the  re- 
lative dimensions  become  smaller  and  smaller 
as  regards  the  head  in  proportion  as  the  animal 
approaches  the  adult  age.  The  seven  rings  of 
the  thorax,  on  the  other  hand,  continue  per- 


756 


CRUSTACEA. 


fectly  distinct,  and  differ  but  little  from  one 
another;  and  the  seven  abdominal  rings,  in 
like  manner,  remain  moveable,  and  only  differ 
from  those  of  the  thorax  as  they  do  from  one 
another  by  a  relatively  inferior  degree  of  deve- 
lopment. In  the  majority  of  the  Isopods  the 
structure  of  the  tegumentary  skeleton  is  essen- 
tially the  same  as  in  the  Amphipods  ;  but  there 
occurs  a  greater  inequality  of  development  be- 
tween the  thoracic  and  the  abdominal  rings, 
most  of  the  latter  remaining  more  or  less  in  a 
rudimentary  state. 

In  the  Apus  and  the  Nebalia  we  conti- 
nue to  find  the  rings  of  the  thoracic  and  abdo- 
minal portions  of  the  tegumentary  skeleton 
nearly  equal  in  size  and  similar  in  form ;  but 
the  cephalic  section,  instead  of  presenting  the 
same  conformation  as  these  two  portions  of  the 
body,  constitutes  superiorly  an  immense  shield, 
which  extends  over  the  rings  of  the  thorax  and 
conceals  them.  This  dorsal  shield  or  buckler, 
which  is  denominated  Carapace  by  zoologists, 
also  occurs  among  the  whole  of  the  Podoph- 
thalmians,  and  more  than  all  besides  conspires 
to  give  to  these  animals  their  distinguishing 
peculiarities  of  shape.  Inquiries,  of  which  it 
would  be  tedious  to  give  a  detailed  account  in 
this  place,  have  led  us  to  discover  that  the 
carapace  of  these  Crustaceans  is  neither  more 
nor  less  than  the  superior  arc  of  the  third  or 
fourth  cephalic  ring,  enormously  developed, 
and  which  in  attaining  its  large  dimensions 
laps  over  and  modifies  the  conformation  of  a 
greater  or  smaller  number  of  the  neighbouring- 
rings.* 

In  the  generality  of  the  Stomapods  the  cara- 
pace does  not  quite  cover  and  conceal  the  two 
first  cephalic  rings,  which  indeed  continue  dis- 
tinct and  moveable ;  but  in  the  whole  of  the 
Decapods  these  rings  cohere  with  one  ano- 
ther and  with  the  following  ones,  and  unite 
more  and  more  intimately  under  the  carapace, 
which  then  covers  the  whole  of  the  head  as  well 
as  the  thorax.  In  the  Macroura  the  anterior 
extremity  of  the  carapace  only  extends  over  the 
ophthalmic  or  first  cephalic  ring ;  but  in  the 
Brachyura  it  bends  around  this  ring  so  as  to 
include  it,  and  to  go  to  unite  underneath  with 
the  next  segment.  As  we  ascend  in  the  series 
of  Crustaceans,  we  observe  the  carapace  en- 
croaching more  and  more  upon  the  thorax. 
In  the  Squillae  the  three  last  cephalic  and  three 
first  thoracic  rings  are  nearly  lost  by  becoming 
blended  with  those  to  which  the  carapace  be- 
longs ;  they  scarcely  retain  any  mobility,  and 
protected  above  by  this  shield,  unite  intimately, 
and  remain  imperfect  in  their  tergal  portions ; 
the  four  last  rings  of  the  thorax  continue,  on  the 
contrary,  free,  and  are  in  almost  every  particular 
similar  to  those  of  the  abdomen.  In  the  Mysis 
this  union  of  the  cephalic  shield  with  the  seg- 
ments of  the  thoracic  division  of  the  tegumen- 
tary skeleton  is  carried  further,  for  there  are 
not  more  than  two  of  these  rings  which  remain 
distinct.  But  it  is  in  the  Decapods  that  the 
carapace  attains  its  greatest  development,  and 

*  See  my  Hist.  Nat.  des  Crustaces,  t.  i.  p.  23. 


that  its  influence  upon  the  evolution  of  the 
thoracic  segments  is  carried  the  farthest. 

In  these  animals  the  framework  of  the  body 
does  not  appear  at  first  sight  to  consist  of  more 
than  two  portions,  the  one  anterior,  formed  by 
the  carapace,  and  representing  the  cephalic  and 
thoracic  segments  conjoined ;  the  other  poste- 
rior, formed  by  the  abdomen.  In  reality,  the 
first  fourteen  rings  of  the  body  are  covered  by 
this  enormous  buckler,  and  are  so  intimately 
conjoined  as  to  have  lost  all  their  mobility ;  the 
whole  of  the  thoracic  segments  thus  hidden 
below  the  carapace,  are  connected  with  it  in 
their  superior  part,  they  are  only  joined  with 
one  another  underneath  and  laterally ;  and  their 
tergal  parts  having,  in  consequence  of  this,  be- 
come useless,  are  no  longer  to  be  found,  being 
in  some  sort  replaced  by  the  great  cephalic 
buckler;  thus  the  whole  of  these  rings,  in  con- 
formity with  this  arrangement,  are  imperfect 
and  open  above. 

Hitherto  we  have  not  been  able  to  deter- 
mine whether  the  carapace  of  the  Podophthal- 
mia  is  formed  at  the  expense  of  the  third  or 
of  the  fourth  ring  of  the  tegumentary  skeleton  ; 
but  we  have  the  strongest  reasons  to  conclude 
that  this  buckler  is  neither  more  nor  less  than 
the  dorsal  arc  of  one  or  other  of  these  cephalic 
rings,  and  not  of  the  two  conjointly.  In  fact 
we  can  here  demonstrate  a  composition  analo- 
gous to  that  which  we  have  already  pointed 
out  as  characteristic  of  every  arc,  whether  supe- 
rior or  inferior,  of  the  different  rings  in  their 
state  of  complete  development,  to  wit,  a  tergal 
portion  and  two  lateral  or  epimeral  pieces.  In 
following  the  embryo  of  the  River-crab  in  its 
progressive  stages  of  development,  Rathke* 
observed  the  carapace  to  be  formed  of  three 
pieces,  which  at  length  became  consolidated 
so  as  to  form  but  one.  In  many  of  the  Deca- 
pods it  is  even  easy  to  perceive  this  structure 
or  composition  in  the  carapace  of  adults,  inas- 
much as  there  exist  lines  marking  the  conjunc- 
tion, and  accurately  indicating  the  respective 
limits  of  the  different  pieces  of  which  this  great 
dorsal  plate  is  composed. 

The  general  form  of  the  carapace  depends  in 
great  measure  on  the  relative  development  of 
these  different  pieces;  in  the  Macroura  the 
tergal  portion  of  the  carapace  extends  but  a 
short  way  backwards,  whilst  the  lateral  or 
epimeral  pieces  reach  as  far  as  the  begin- 
ning of  the  abdomen,  and  being  no  longer 
kept  at  a  distance  by  the  tergum,  meet  in  the 
median  line  of  the  back,  and  are  there  con- 
joined. In  the  Brachyura,  on  the  contrary,  the 
tergal  portion  is  that  which  is  especially  deve- 
loped, so  that  it  constitutes  the  whole  of  the 
upper  part  of  the  carapace,  whilst  the  lateral 
pieces,  thrust  outwards  and  underneath,  only 
form  a  narrow  band  above  the  bases  of  the  ex- 
tremities. 

It  is  also  in  consequence  of  modifications 
analogous  to  those  on  which  the  existence  of  the 
carapace  depends,  that  in  other  Crustacea  the 

*  Untersuclmngen  ucber  die  Bildung  des  Fluss- 
krebses,  &c.  Tr.  iu  Annales  des  Sciences  Nat.  t.  20. 


CRUSTACEA. 


757 


tegumentary  skeleton  presents  the  most  singular 
forms :  thus  among  the  Limmadia  and  the 
Cypris,  the  pieces  which  are  analogous  to  the 
epimeral  or  lateral  pieces  of  this  cephalic 
buckler,  acquire  a  great  extension,  whilst  the 
tergal  portion  of  the  arc  to  which  they  belong 
continues  rudimentary  or  proves  entirely  abor- 
tive, so  that  they  constitute  two  large  valves 
covering  the  whole  body  of  the  animal,  and 
bearing  considerable  resemblance  to  the  shells 
of  certain  acephalous  Mollusks.  The  dorsal 
laminae  which  in  the  Pandarus  form  appendices 
on  the  back  similar  to  Elytra,  and  those  which 
in  the  Anthostomata  form  a  kind  of  sheath 
around  the  posterior  part  of  the  body,  are  also 
formed  by  the  anomalous  development  of  cer- 
tain parts  of  both  the  dorsal  and  ventral  arcs  of 
the  two  posterior  thoracic  rings. 

The  inferior  arcs  of  the  thoracic  rings  of  the 
tegumentary  skeleton  of  the  Decapoda,  by 
their  intimate  union,  form  a  kind  of  ventral 
shield,  named  sternal  plastrum,  upon  which 
lines  of  conjunction  indicate  the  respective 
limits  of  the  greater  number  of  the  segments,  as 
well  as  of  the  sternal  and  episternal  pieces  of 
which  these  are  composed.  In  the  Decapoda 
Macroura  and  Anomoura,  this  plastrum  is  in 
general  very  narrow,  but  in  the  Brachyura  it  is 
expanded  to  such  a  degree  as  frequently  to  con- 
stitute a  great  and  nearly  circular  disc.  In  the 
whole  of  these  Crustaceans,  the  lateral  pieces  of 
the  thoracic  rings  are  conjoined,  like  those  of 
the  inferior  arc  of  the  same  segments,  and  form 
on  either  side  of  the  middle  portion  of  the 
body  a  septum  which  is  covered  by  the  cara- 
pace, and  which  is  known  among  anatomists 
under  the  name  of  the  vault  of  thejluncs.  In 
the  Macroura  this  septum  is  nearly  vertical, 
but  in  the  Brachyura  it  is  oblique,  or  even 
almost  horizontal. 


Fig.  383. 


Fig.  384. 


Lateral  portion  of  the  thorax  of  a  Decapod. 

a,  the  epimeral  pieces  united  to  form  the  vault  of 
the  flancs;  b,  the  sternum;  c,  the  apodemata 
rising  from  the  sternum  and  separating  the  in- 
sertions of  the  legs. 

It  is  among  those  Crustaceans  the  thoracic 
rings  of  whose  tegumentary  skeleton  blend  or 
become  consolidated  in  this  manner,  and  ac- 
quire dimensions  so  considerable,  that  the  struc- 
ture of  this  portion  of  the  frame-work  also  exhi- 
bits the  utmost  extent  of  complication,  in  con- 
sequence of  the  existence  of  large  apodemata  in 
their  interior.  These  septa  are  of  two  kinds ; 
the  one,  styled  sternal  apodemata,  arise  from 
the  lines  of  consolidation  of  the  thoracic  sternal 
pieces;  the  other,  named  epimeral  apodcmata, 


Vertical  section  of  a  portion  of  the  thorax  of  one  of 
the  Brachyura. 

a,  sternum,  with  a  sternal  apodema  rising  from  it; 
b,  epimera  from  the  inner  surface  of  which  an 
epimeral  apodema  descends  to  join  the  sternal 
apodema,  and  thus  form  a  septum  between  the 
thoracic  cells. 

arise  in  a  similar  manner  from  the  epimeral 
pieces  of  the  same  rings.  They  are  met  with 
among  the  Macroura  and  Anomoura,  as  well  as 
among  the  Brachyura ;  but  it  is  among  these  last 
that  they  acquire  their  highest  development; 
their  direction,  vertical  to  the  internal  planes  of 
the  rings,  and  the  unions  of  those  that  rise  from 
the  inferior  aspect  or  floor  with  those  that  des- 
cend from  the  arched  superior  surface,  give  rise 
to  the  most  singular  combinations  and  forms,  too 
multifarious  to  admit  of  description  in  an 
article  of  the  extent  of  that  in  which  we  are 
engaged,  but  the  final  effect  of  which  is  the 
establishment  of  cells,  divided  from  one  an- 
other by  vertical  septa,  and  corresponding  to 
each  ring,  and  further  intersected  in  the  direc- 
tion of  their  height,  in  a  certain  number  of 
species,  and  divided  into  two  stages  by  means 
of  horizontal  reduplications. 

It  is  within  these  different  cells  that  the 
muscles  and  principal  vessels  of  the  thorax  are 
lodged  in  the  Brachyura ;  holes  left  at  the  con- 
junctions of  these  laminae  admit  of  the  com- 
munication of  the  cells  two  and  two,  either 
through  the  vertical  septa  or  through  the  hori- 
zontal floors  which  divide  the  superposed  cells, 
and  it  is  by  means  of  these  holes  of  conjunc- 
tion that  the  anastomoses  of  the  vessels  of  one 
ring  take  place  with  those  of  the  neighbouring 
ring,  as  we  shall  see  presently. 

In  the  Macroura,  again,  this  structure  does 
not  occur,  in  consequence  of  which  other  means 
of  communication  between  the  vessels  of  the 
different  segments  require  to  be  established, 
the  nature  of  which  we  shall  also  have  to  inves- 
tigate before  long.  Generally  speaking,  the 
disposition  of  these  cells  and  of  the  septa 
which  form  them  varies  considerably  in  the 
Brachyura  and  the  Macroura.  Certain  pro- 
longations from  the  superior  and  internal  angle 
of  the  sternal  apodemata,  by  their  union  in  the 
median  line,  after  bending  from  before  back- 
wards, even  form  a  longitudinal  canal,  which 
extends  through  almost  the  whole  length  of  the 
thorax.  This  is  the  sternal  canal,  destined  to 
lodge  the  ganglionic  nervous  cord,  and  to  serve 
as  the  chief  venous  reservoir. 

It  has  long  been  admitted  as  an  axiom  in 
animal  physics,  that  when  any  particular  part 
of  the  body  acquires  a  very  high  degree  of  de- 
velopment, certain  other  parts  stop  short  of 
their  ordinary  state  of  evolution,  as  if  the  former 
had  obtained  their  unusual  increment  at  the  cost 


758 


CRUSTACEA. 


Fig.  385. 


Thorax  of  the  Astacus  Fluviatilis,  showing  the  dis- 
position of  the  apodemata  and  the  thoracic  cells. 

of  the  latter.  This  rule,  which  has  been  dis- 
cussed by  M.  Geoffrey  St.  Hilaire  under  the 
title  of  la  loi  de  balancement  organique,  or  law 
of  organic  equivalents,  is  found  to  apply  in  the 
present  instance;  for  the  Crustacea  in  which 
the  cephalic  portion  of  the  tegumentary  skele- 
ton is  developed  in  the  greatest  degree,  (viz. 
the  Brachyura)  present  the  abdominal  portion 
of  the  body  of  very  small  dimensions ;  whilst, 
on  the  other  hand,  in  the  Macroura,  or  those 
species  in  which  the  abdominal  portion  of 
the  body  arrives  .at  its  maximum  of  develop- 
ment, and  performs  a  very  important  office  in 
the  business  of  locomotion,  the  cephalic  por- 
tion is  relatively  greatly  inferior  in  size. 

With  regard  to  its  disposition  the  abdomen 
is  simple  enough;  the  rings  of  which  it  con- 
sists are  in  general  moveable  upon  one 
another,  and  even  when  they  are  consolidated, 
present  no  apodemata  projecting  from  their 
interior.  It  is  also  deserving  of  remark  that 
the  elementary  pieces  of  the  different  rings  are 
not  very  distinct,  and  sometimes  even  appear 
to  be  partially  wanting. 

Let  us  now  go  on  to  examine  the  portion 
of  the  tegumentary  skeleton  belonging  to  the 
extremities  or  that  portion  of  the  external 
skeleton  of  the  Crustacea  which  may  be  re- 
garded as  an  appendage  to  the  more  essen- 
tial covering  of  the  head,  thorax,  and  ab- 
domen. 

The  Crustacea  present  this  invariable  cha- 
racter, that  the  whole  of  the  appendages  belong 
exclusively  to  the  inferior  arc  of  their  tegu- 
mentary rings,  a  point  in  which  they  resemble 
the  Arachnidans,  and  differ  like  these  from 
Insects,  in  which  one  or  two  of  the  thoracic 
rings  generally  present  a  pair  of  extremities 
supported  by  the  superior  arcs,  as  in  the  An- 
nelidans,  in  which  the  dorsal  segment  of  each 
of  the  rings  almost  always  carries  a  pair  of 
extremities  fashioned  in  the  same  manner  as 
those  belonging  to  the  ventral  arcs.*  We 
have  already  said  that  a  pair  of  appendages 
ought  to  be  found  attached  to  each  ring ;  but 
it  very  frequently  happens  that  many  of  the 
pairs  are  completely  checked  in  their  develop- 

*  Vide  Annelida,  p.  167. 


ment,  or  that  the  forms  they  assume,  in  har- 
mony with  the  uses  they  serve,  render 
them  liable  to  be  mistaken.  It  is  very  dif- 
ferent in  the  embryo ;  here,  in  fact,  as  among 
the  simplest  forms  of  the  series,  the  whole 
of  the  extremities  are  at  first  similar;  and 
it  is  only  in  consequence  of  ulterior  develop- 
ments that  each  pair  finally  assumes  diver- 
sities of  form  and  character  in  relation  with 
the  various  functions  to  which  they  are  espe- 
cially destined. 

In  its  most  perfect  state  of  development, 
the  extremity  in  the  Crustacean  consists  of  three 
principal  parts :  the  stem  (a),  which  is  the  most 


Fig.  386. 


essential  and  most  constant  part,  formed  of  a 
variable  number  of  articulations ;  the  palp  (6), 
an  appendage  which  is  detached  from  one  of  the 
three  first  articulations  of  the  stem,  but  almost 
always  from  the  first ;  and  the  whip  (fouetj  (c), 
which  is  sent  off  above  and  to  the  outer  side  of 
the  palp.  It  but  rarely  happens,  however,  that 
these  three  organs  exist  simultaneously ;  occa- 
sionally not  more  than  one  of  them  can  be 
demonstrated ;  and  sometimes  the  whole  three 
are  altogether  wanting. 

Fig.  387. 


First  cephalic  ring  of  the  Squilla  separated  from 
the  rest  of  the  head,  and  bearing  one  of  the 
ocular  peduncles. 

The  first  ring  presents  no  appendages  except 
in  the  very  highest  Crustaceans,  and  even  then 
they  are  simple  in  their  composition,  and  never 
exhibit  more  than  the  stem,  which  arises  from 
a  more  remote  check  to  their  development 
dating  from  about  the  commencement  of  their 
embryonic  evolution;  these  are  the  ocular  pe- 
duncles. 

The  second  and  third  pairs  of  extremities 
constitute  the  antenna.  These  are  wanting  in 
a  certain  number  of  the  inferior  species,  and 
even  in  those  among  which  they  occur,  they 
vary  considerably  in  their  structure  :  they  may 
for  instance  present  one  only,  or  two,  or  the 
whole  of  the  three  elements  of  which  we  have 
spoken.  But  as  the  three  first  pairs  of  ap- 


CRUSTACEA. 


388- 


a,  second  thoracic  ring  of  the  Squilla ;    6,  one  of 
the  small  antenna:. 

pendages  belong  especially  to  the  function  of 
sensation,  and  as  we  shall  have  to  revert  to 
these  at  a  later  period,  and  give  an  ample  de- 
scription of  their  structure,  we  shall  not  enter 
upon  this  subject  farther  at  present. 


759 

added  to  this  first  pair,  and  these  are  desig- 
nated jaws  or  maxilla.  In  the  majority  of 
instances,  moreover,  the  three  succeeding  pairs 
assist  the  three  preceding;  and  as  they  are 
frequently  more  especially  apportioned  to  loco- 
motion, the  two  last  in  particular,  whilst  in 
some  cases  they  serve  for  the  two  functions  at 
one  and  the  same  time,  they  have  been  de- 
signated by  anatomists  and  naturalists  the 
maxillary  limbs  (picds-machoirs}:  these  we 
shall  describe  when  we  come  to  speak  of  the 
apparatus  of  digestion. 

As  to  the  five  pairs  which  we  have  already 
mentioned  as  essentially  ambulatory  (see 
fg.  382),  they  present  in  the  Brachyura  no 
more  than  a  simple  stem,  composed  of  six 
articulations  ;  whilst  in  the  Astacus  and  allied 
genera,  we  find  a  flabelliform  appendage  or 


Fig.  389. 


Third  and  fourth  cephalic  rings  of  the  Squilla  : 
a,  carapace ;  b,  one  of  the  posterior  antennae  j 
c,  one  of  the  mandibles. 

The  eleven  pairs  of  appendages  which  suc- 
ceed are  variously  apportioned  between  the 
functions  of  digestion  and  locomotion,  to  which 
last  the  five  hindmost  pairs  are  entirely  dedi- 
cated in  the  Decapods.  In  other  Crustacea, 
again,  the  first  pair  only  is  set  apart  in  an 
especial  manner  for  the  office  of  mastication, 
all  the  others  then  serving  for  locomotion,  and 
this  pair  is  in  consequence  very  generally  de- 
scribed under  the  name  of  mandibles;  very 
commonly  one  and  even  two  other  pairs  are 


By- 


of  appendages  existing  simultaneously 
and_£     wh|n         ki    Sof  respiratl  '' 
see  h'w  it  j*^  ^  in  / 
these  animals  §£  whip  of  the  ^  ^  extremities 

assumes  a  vesicular  structure,  and  becomes 
the  organ  of  this  important  function. 

The  same  peculiarity  is  observed  in  the 
appendages  of  the  abdominal  extremities 
of  a  great  number  of  species  ;  but  among 
the  members  of  the  most  elevated  tribes, 
these  appendages  are  but  very  slightly 
developed,  and  appear  to  have  no  other 
use  than  to  attach  the  eggs  along  the  in- 
ferior surface  of  the  abdomen. 

Fig.  390. 


Abdomen  of  the  female  Maja 

Squintido. 

a,  the  abdominal  appen- 
dages. 


We  shall  not  at  present  enter  upon  the  con- 
sideration of  the  forms  of  the  thoracic  and 
abdominal  extremities,  having  it  in  view  to 
take  up  the  subject  when  we  come  to  examine 
these  appendages  as  the  organs  of  prehension, 
and  as  fulfilling  important  offices  in  locomotion. 

Before  quitting  the  study  o/  the  tegumen- 
tary  skeleton,  to  go  on  to  that  of  the  extre- 
mities considered  especially  as  the  organs  of 
locomotion,  we  think  it  necessary  to  say  a  few 
words  upon  the  moult  or  process  by  which  the 
tegumentary  covering  of  the  whole  of  the  Crus- 
tacean is  cast  off  and  renewed. 

The  necessity  for  this  operation  is  a  con- 
sequence of  the  very  nature  of  the  envelope  : 
like  every  other  epidermic  covering,  the  pro- 
duct of  secretion,  the  shell  of  the  Crustacea  is 
closed  in  on  every  side,  and  can  only  increase 
in  thickness,  so  that  all  growth  would  be  pre- 
vented in  the  body  of  these  animals  were  they 
denied  the  power  of  freeing  themselves  from 
time  to  time  of  their  prison.  Accordingly  they 
have  this  power;  and  as  might  have  been  ex- 
pected the  shell  is  cast  by  so  much  the  more 
frequently  as  the  animal  is  younger,  inasmuch 


700 


CRUSTACEA. 


as  the  growth  is  then  most  rapid;  as  many 
as  eight  changes  of  the  tegumentary  envelope 
have  been  observed  to  take  place  in  the  course 
of  seventeen  days  in  the  young  Daphnia;  whilst 
in  adult  Crustacea  the  change  is  not  in  general 
effected  oftener  than  once  a  year. 

Reaumur  watched  the  phenomenon  through 
its  whole  course,  and  has  noted  it  with  all  its 
details  as  it  occurs  in  the  Astacus  fluviatilis* 
It  takes  place  in  this  species  towards  the  end 
of  summer  or  beginning  of  autumn.  A  few 
days  of  fasting  and  sickness  precede  it,  during 
which  the  carapace  becomes  loosened  from  the 
corium  to  which  it  adhered,  and  which  im- 
mediately begins  to  secrete  a  new  one,  soft 
and  membranous  at  first,  but  soon  becoming 
harder  and  harder,  and  finally  completely  cal- 
careous. In  this  way  the  animal  before  long 
finds  itself  free  from  all  connexion  with  its 
old  envelope,  and  it  has  only  to  make  its 
escape.  This  last  operation  is  announced  by 
symptoms  of  inquietude.  The  creature  rubs 
its  legs  one  against  another,  and  then  throwing 
itself  upon  its  back  begins  to  shake  itself, 
puffs  itself  out,  so  as  to  tear  the  membrane 
which  connects  the  carapace  with  the  abdo- 
men, and  to  raise  the  carapace  itself.  After 
sundry  intervals  of  rest  and  agitation  of  longer 
or  shorter  duration,  the  carapace  is  raised  com- 
pletely;  the  animal  extricates  its  head,  its  eyes, 
and  its  antennae.  The  operation  of  freeing 
its  extremities  appears  to  be  the  most  difficult, 
and  would  even  be  impossible  did  not  the 
solid  covering  of  these  parts  split  longitudi- 
nally; but  in  spite  of  every  assistance,  it  not 
unfrequently  happens  that  the  animal  leaves 
one  or  two  of  its  limbs  impacted  within  the 
old  sheath,  and  occasionally  even  perishes 
through  inability  to  escape  completely  from  its 
shell.  The  abdomen  is  the  last  division  of 
the  body  which  clears  itself  of  the  old  enve- 
lope. All  the  parts  of  the  tegumentary  ske- 
leton which  had  only  been  separated  from  one 
another,  without  however  having  undergone 
any  softening,  or  fracture,  or  separation,  fall 
one  upon  another  in  resuming  their  old  posi- 
tions, so  as  to  represent  the  complete  external 
form  of  the  creature  with  the  whole  of  its 
solid  internal  as  well  as  external  parts ;  even 
the  eyes,  the  antennae,  and  the  thoracic  cells 
formed  by  the  sternal  and  epimeral  apodemata, 
may  be  distinguished.  The  operation  now 
described  does  not  in  general  occupy  more 
than  half  an  hour  in  the  performance ;  and 
only  two  or  three  days,  or  even  no  more  than 
four-and-twenty  hours  are  required  to  convert 
the  soft  and  membranous  envelope  with 
which  the  corium  or  naked  body  of  the 
animal  is  surrounded,  into  a  firm  calcareous 
covering  similar  to  the  one  which  has  just  been 
got  rid  of.  The  new  envelope  presents  the 
same  appendages  as  the  former  one,  even  the 
same  hairs ;  but  these,  instead  of  being  con- 
tained within  the  old  ones,  as  Reaumur  ima- 
gined, exist  ready  formed  in  the  new  envelope, 
but  turned  in  towards  the  interior,  like  the 
fingers  of  a  glove  turned  in  upon  themselves. 

*  Memoires  de  I'Academie  des  Sciences,  1718. 


There  are  some  species,  such  as  the  Crabs 
and  the  Brachyura  generally,  in  which  the 
carapace  presents  a  considerable  expansion  on 
either  side,  forming  two  large  compartments 
in  which  the  greater  mass  of  the  thoracic  vis- 
cera is  contained.  Under  these  circumstances 
it  would  be  impossible  for  the  animal  to  escape 
from  its  dorsal  covering  by  the  relatively  in- 
considerable opening  which  this  part  presents 
on  its  inferior  aspect.  This  renders  it  neces- 
sary that  the  carapace,  instead  of  being  cast 
off  by  simply  rising  in  a  single  piece, 
should  give  way  and  separate  in  some  direction 
or  another,  and  this  it  does  by  splitting  along 
the  curved  lines,  extending  on  either  side  from 
the  mouth  to  the  origin  of  the  abdomen,  in  the 
course  of  which  the  epimeral  pieces  cohere 
with  the  dorsal  one.* 

The  time  occupied  in  the  business  of  throw- 
ing off  the  shell  varies  considerably  in  dif- 
ferent species;  it  is  also  dependent  on  at- 
mospheric influences.  It  is  the  same  also, 
in  regard  to  the  number  of  days  necessary  to 
give  to  the  new  epidermic  layer  the  consistency 
of  the  old  tegumentary  covering.  A  general 
remark,  however,  and  one  which  is  applicable 
to  the  whole  of  the  species  that  have  been 
duly  observed,  especially  those  that  are  found 
along  the  shores  of  France,  is  this, — that  the 
period  which  precedes  as  well  as  that  which 
follows  the  change  of  the  shell  is  one  of  rest- 
lessness and  evident  illness.  The  muscles  of 
these  creatures  are  then  flaccid,  the  flesh  is  soft 
and  watery,  and  as  food  they  are  rejected  as 
tasteless  and  held  unwholesome.  This  would 
not  appear  to  be  the  case  with  the  Land-crab, 
however,  according  to  the  statements  of  several 
travellers,  who  inform  us  that  the  flesh  of  this 
species  is  never  in  greater  perfection  than  during 
the  season  of  the  moult. 

A  phenomenon,  which  has  some  analogy  with 
the  renovation  of  the  tegumentary  skeleton, 
but  which  is  much  more  curious,  is  the  repro- 
duction of  the  legs  of  these  animals.  Most 
Crustacea  cast  off  their  claws  very  easily  and 
without  apparent  pain ;  the  separation  always 
takes  place  in  a  determinate  point  near  the 
basis  of  the  member  (in  the  second  articula- 
tion), and  is  soon  followed  by  the  formation 
of  a  cicatrice,  from  the  surface  of  which  sprouts 
out  a  small  cylindrical  appendage ;  this  shortly 
after  presents  distinct  articulations,  and  re- 
sembles in  miniature  the  organ  it  is  destined 
to  form,  but  its  growth  is  slow,  and  it  does  not 
for  some  time  attain  its  full  size.  If  one  of 
the  limbs  be  severed  in  any  other  part,  the 
wound  continues  to  bleed,  and  no  renovating 
process  begins  unless  the  animal,  by  a  violent 
muscular  contraction,  succeeds  in  breaking  off 
the  stump  in  the  articulation  above  mentioned. 
The  kind  of  solid  sheath  formed  by  the 
tegumentary  skeleton  of  the  Crustacea,  and 
which  includes  in  its  interior  the  whole  of 
the  viscera  and  other  soft  parts  of  these  ani- 
mals required  to  be  so  constructed  as  not  to 
oppose  locomotion;  consequently  there  exist, 

*  Collinson,  Phil.  Trans.  1746  and  1751  ;    Hist. 
Nat.  des  CrustacSs,  t.  i.  p.  56. 


CRUSTACEA. 


7CI 


either  between  the  different  rings  of  the  body 
or  the  various  constituent  elements  of  the 
limbs,  articulations  destined  to  admit  of  mo- 
tion to  a  greater  or  less  extent,  between  these 
different  pieces.  The  structure  of  these  arti- 
culations is  of  the  most  simple  kind ;  the 
moveable  piece  rests  upon  that  which  precedes 
it  by  two  hinge-like  joints  situated  at  the  two 
extremities  of  a  line  perpendicular  to  the  plane 
in  which  the  motion  takes  place.  In  the  in- 
ternal portion  of  the  edge  of  the  moveable 
piece  comprised  between  the  joints,  there  exists 
a  notch  of  greater  or  less  depth,  destined  to 
admit  of  flexion,  whilst  on  the  opposite  or 
external  sidt>,  the  same  edge  generally  glides 
under  that  of  the  preceding  piece.  This  kind 
of  articulation,  whilst  it  is  the  most  favourable 
to  precision  of  movement  and  to  strength,  has 
the  disadvantage  of  admitting  motion  in  one 
plane  only ;  therefore  the  whole  of  the  rings 
of  the  body,  the  axis  of  motion  being  entirely 
parallel,  cannot  move  save  in  a  vertical  plane ; 
but  nature  has  introduced  a  kind  of  corrective 
of  this  disadvantage  in  the  structure  of  the 
limbs,  by  changing  the  directions  of  the  arti- 
cular axes,  whence  ensues  the  possibility  of 
general  motions  being  performed  in  every  di- 
rection. Between  the  two  fixed  points  two 
opposed  empty  spaces  are  observed,  left  by 
the  rings  severally,  and  destined  to  admit  of 
the  occurrence  of  motions  of  flexion  and  ex- 
tension. The  tegumentary  membrane  which 
fills  it  never  becomes  encrusted  or  calcareous, 
but  always  continues  soft  and  flexible. 

The  tegumentary  skeleton,  of  which  we 
have  thus  taken  a  summary  view,  supplies  the 
apparatus  of  locomotion  with  fixed  points  of 
action  as  well  as  with  the  levers  necessary  to 
motion.  The  immediate  or  active  organs  of 
this  apparatus  are  the  muscles,  the  colour  of 
which  is  white,  and  the  structure  of  which 
presents  no  peculiarity  worthy  of  notice.  They 
are  attached  to  the  pieces  which  they  are  re- 
quired to  move  either  immediately,  or  by  the 
intermedium  of  horny  or  calcareous  tendons, 
which  are  implanted  upon  the  edge  of  the 
segment  to  which  they  belong.  To  the 
fixed  point  they  are  most  commonly  at- 
tached immediately.  Their  structure  is  sim- 
ple, and  each  segment,  in  fact,  as  has  al- 
ready been  said,  being  contrived  to  move 
in  one  fixed  and  determinate  plane,  the  mus- 
cles which  communicate  motion  to  it,  can 
constitute  no  more  than  two  systems  anta- 
gonists to  each  other,  the  one  acting  in  the 
sense  of  flexion,  by  which  the  segment  moved 
is  approximated  to  that  which  precedes  it, 
the  other  in  the  sense  of  extension,  by  which 
the  segment  is  brought  into  the  position  most 
remote  from  the  centre  of  motion.  The  mus- 
cles that  produce  these  opposite  effects,  as 
might  have  been  concluded,  are  found  im- 
planted into  the  opposite  arms  of  the  lever 
upon  which  their  energy  is  expended. 

The  motions  in  flexion  tend  universally  to 
bring  the  extremities  and  the  different  rings 
towards  the  ventral  aspect  of  the  body ;  it  is 
consequently  upon  this  aspect  that  the  flexor 
muscles  are  inserted,  and  these  are  in  general 


VOL.  I. 


the  more  powerful.  On  the  contrary,  and  in 
accordance  with  the  nature  of  the  motion  pro- 
duced, it  is  upon  the  superior  or  dorsal  aspect 
of  the  segments  that  the  extensor  muscles  are 
attached.  In  the  trunk  the  two  orders  of  mus- 
cles generally  form  two  distinct  layers,  the  one 
superficial,  the  other  deep  ;  the  former  thin  and 
sometimes  absent,  the  second,  on  the  contrary, 
very  powerful  wherever  powerful  motions  are 
required.  The  muscles  generally  extend  from 
the  arc  above  to  the  one  immediately  below, 
passing  for  the  most  part  from  the  anterior 
edge  of  the  upper  to  the  anterior  edge  of  the 
lower  segment.  The  extent  and  the  direction 
of  the  flexion  of  which  any  segment  is  sus- 
ceptible, depend  on  the  size  of  the  inter- 
annular  spaces  above  or  below  the  ginglymoid 
points;  and  as  these  spaces  are  in  general  of 
considerable  magnitude  on  the  ventral  aspect, 
whilst  the  superior  arcs  are  in  contact  and  can 
only  ride  one  over  another  in  a  greater  or  less 
degree,  it  is  only  downwards  that  the  body  can 
be  bent  upon  itself;  while  upwards,  or  in  the 
sense  of  extension,  it  can  hardly  in  general  be 
brought  into  the  horizontal  line. 

Thus  far  what  has  been  said  applies  more 
especially  to  the  rings  of  the  body,  but  the 
extremities  present  nothing  that  is  essentially 
different  either  as  regards  the  mode  in  which  the 
tubular  segments  are  articulated  to  one  another, 
or  as  regards  the  mode  in  which  the  muscles 
are  inserted.  Each  of  these  indeed  having  but 
one  kind  of  motion,  and  even  that  very  limited 
in  its  extent,  nature  has  aided  the  deficiency, 
as  has  been  stated,  by  increasing  the  number 
of  articulations,  by  which  extent  of  motion  is 
conferred,  and  in  varying  the  direction  of  the 
articular  axes,  an  arrangement  by  which  the 
animal  obtains  the  ability  of  moving  in  every 
direction,  but  at  the  expense  both  of  power,  ra- 
pidity, and  precision  in  its  motions.  Each  seg- 
ment of  a  limb  encloses  the  muscles  destined 
to  move  that  segment  which  succeeds  it,  un- 
less it  be  too  short  and  weak  for  this  end,  in 
which  case  the  muscles  themselves  have  their 
origin  at  some  point  nearer  to  the  median  plane 
of  the  body.  As  a  general  law  the  muscles 
are  observed  to  be  more  powerful  in  proportion 
as  they  are  nearer  to  the  centre,  which  is  to  be 
explained  by  the  fact  that  each  motion  they 
then  communicate  is  transmitted  to  a  larger 
portion  of  a  limb,  to  a  lever  longer  in  that 
sense  in  which  it  is  disadvantageous  to  the 
power.  Occasionally,  however,  the  two  last 
segments  of  a  member  are  converted  into  a 
sort  of  hand,  and  in  this  case  the  penul- 
timate segment  sometimes  includes  a  mus- 
cular mass  which  may  surpass  in  power  the 
same  system  in  the  whole  of  the  limb  besides. 
Those  muscles  that  put  an  extremity  generally 
into  motion,  are  attached  to  the  sides  of  the 
thoracic  cavity,  and  the  apodemata  supply 
them  with  surfaces  of  insertion  of  great  extent 
and  very  favourably  situated  as  regards  their 
action.  They  occupy  the  double  rank  of  cells 
formed  by  these  lamina?;  but  they  vary  too 
much  in  their  mode  of  arrangement  to  admit 
of  our  saying  any  thing  general  upon  this  head. 
The  motions  of  translation,  or  from  place  to 

3  D 


7G2 


CRUSTACEA. 


place,  the  only  kind  upon  which  it  seems  neces- 
sary to  say  anything  here,  are  effected  in  two 
modes,  either  by  the  alternate  flexion  and  ex- 
tension of  the  trunk,  or  by  the  play  of  the  limbs. 

In  those  Crustacea  which  are  formed  essen- 
tially for  swimming,  the  posterior  part  of  the 
body  is  the  principal  agent  in  enabling  the 
animal  to  change  its  place ;  but  here  the  mo- 
tions, instead  of  being  lateral,  are  vertical; 
and  instead  of  causing  the  creature  to  ad- 
vance they  cause  it  to  recede :  it  is  by  bend- 
ing the  abdomen  suddenly  downwards,  and 
bringing  it  immediately  under  the  sternum, 
that  it  strikes  the  water,  and  consequently  by 
darting  backwards  that  the  animal  makes  its 
way  through  that  liquid.  From  what  has  now 
been  said  it  may  be  imagined  that  the  Crustacea 
whose  conformation  is  the  best  adapted  for 
swimming,  have  the  abdomen  relatively  largely 
developed,  and  this  is,  in  fact,  what  we  always 
observe;  the  Amphipoda  and  Decapoda  ma- 
croura  are  examples ;  whilst,  in  the  walking 
Crustacea,  such  as  the  Crabs,  the  Caprella, 
the  Oniscus,  &c.  this  portion  of  the  body 
attains  but  very  insignificant  dimensions. 

In  the  swimming  Crustacea  the  appendages 
of  the  penultimate  segment  of  the  abdomen 
also  become  important  organs  of  locomotion, 
inasmuch  as  they  for  the  most  part  terminate 
in  two  broad  horizontal  plates,  which,  with 
the  last  segment,  also  become  lamelliform,  con- 
stitute an  extensive  caudal  fin  arranged  in  the 
manner  of  a  fan. 

We  have  already  said  that  the  thoracic  ex- 
tremities alone  constitute  true  ambulatory 
limbs.  When  destined  for  swimming  only, 
their  segments  are  lamelliform,  and  the  palp, 
as  well  as  the  stem,  contributes  to  form  the 
kind  of  oar  which  each  of  them  then  con- 
stitutes. The  Copepoda  supply  us  with  in- 
stances of  thoracic  extremities  particularly 
destined  for  swimming,  and  a  corresponding 
structure  is  observed  in  certain  Podophthalmia, 
such  as  the  Mysis.  (See  fig.  386.) 

To  conclude,  this  stemmatous  portion  of  the 
thoracic  extremities,  whilst  it  still  preserves 
the  general  form  which  we  have  assigned  it,  is 
modified  in  some  cases  to  serve  for  walking 
as  well  as  swimming,  or  to  aid  the  animal  as 
an  instrument  for  burrowing  with  facility,  and 
making  a  cavity  for  shelter  among  the  sand. 
Thus  in  the  Decapods  that  burrow,  the  last  seg- 
ment of  the  tarsus  assumes  a  lanceolated  form, 
and  in  the  swimming  Brachyura,  the  same 
segment,  especially  of  the  last  pair  of  extre- 
mities, appears  entirely  lamellar. 

We  have  only  further  to  add  that  in  a  great 
number  of  species  one  or  several  pairs  of  the 
thoracic  extremities  are  modified  so  as  to 
become  instruments  of  prehension;  some- 
times it  is  the  last  segment  of  the  limb  which, 
acquiring  more  than  usual  mobility,  bends  in 
such  a  manner  as  to  form  a  hook  with  the 
preceding  segment ;  sometimes  it  is  this  penul- 
timate segment  which  extends  below  or  by  the 
side  of  the  last,  so  as  to  form  a  kind  of  im- 
moveable  finger  with  which  it  is  placed  in 
opposition.  In  the  first  instance  these  instru- 
ments are  denominated  subcheliform  claws,  in 


the  second  chela  simply,  or  cfieliform  claws. 
We  shall  revert  to  these  organs  when  we  come 
to  treat  of  the  apparatus  of  digestion. 
§  2.  Apparatus  of  Sensation. 

A.  Nervous  System.-^When  endeavouring 
to  form  as  accurate  and  complete  an  idea  as 
possible  of  the  tegumentary  skeleton  of  the 
Crustacea,  we  began  by  studying  it  in  its  suc- 
cessive states  of  development  in  the  embryo, 
and  then  compared  the  various  stages  of 
transition  in  which  it  met  our  observation, 
with  the  permanent  conditions  in  which  it 
finally  remains  in  the  organic  series,  classed 
in  conformity  with  the  structural  affinities  of 
the  different  genera.  In  the  study  of  the 
nervous  system,  upon  which  we  are  now  about 
to  enter,  the  same  mode  of  proceeding  will 
lead  us  to  analogous  results. 

The  deep  situation  of  the  nervous  system, 
and  the  transparency  of  the  filaments  and 
various  masses  which  compose  it,  are  each 
obstacles  to  its  observation  until  it  has  arrived 
at  a  somewhat  advanced  stage  of  development. 
It  was,  in  fact,  only  after  the  sternal  canal  had 
begun  to  appear  under  the  form  of  an  enlarge- 
ment, edged  by  a  double  series  of  tubercles, 
which  prove  to  be  the  rudiments  of  the  motor 
muscles  of  the  extremities,  that  Rathke*  was 
able  to  catch  a  sight  of  the  earliest  traces  of  the 
nervous  system  in  the  Astacus  fluviatilis,  and 
even  this  was  no  more  than  the  portions  be- 
longing to  the  head  and  thorax.  All  that  can 
be  seen  then  amounts  to  very  little ;  in  the  part 
behind  the  mouth,  eleven  pairs  of  whitish  spots 
are  arranged  in  two  longitudinal  series  perfectly 
distinct  from  one  another,  and  situated  on  either 
side  of  the  mesial  plane.  It  is  otherwise  easy 
to  perceive  that  a  pair  of  these  spots  corres- 
ponds to  each  ring,  setting  out  from,  but  in- 
cluding those  of  the  mandibles.  Neither  the 
O3sophageal  cords  nor  the  cephalic  ganglions 
are  then  distinct. 

At  a  later  period  these  rudiments  of  the 
nervous  system  undergo  remarkable  modifica- 
tions. The  six  first  ganglions  of  each  series 
approach  those  that  are  symmetrical  with  them 
severally,  so  as  to  become  united  along  the 
median  line,  and,  at  length,  to  form  a  simple 
chain  of  ganglions  corresponding  to  the  six 
rings,  whose  appendages  are  the  mandibles 
and  the  five  pairs  of  maxillary  extremities. 
The  ganglions,  on  the  contrary,  which  corres- 
pond to  the  five  posterior  thoracic  rings,  continue 
to  form  a  double  series.  During  this  time  the 
sternal  canal  is  evolved  so  as  to  surround  the 
nervous  system  with  a  firm  and  solid  sheath. 
At  a  period  of  the  incubation  still  farther  ad- 
vanced, that  is  to  say,  during  the  time  which 
elapses  from  the  birth  of  the  young  Crustacean 
to  that  at  which  it  attains  its  full  growth,  new 
and  important  changes  take  place.  First,  the 
four  most  anterior  cesophageal  tubercles,  in 
other  words,  those  which  correspond  to  the 
mandibles,  to  the  jaws,  and  to  the  first  pair  of 
maxillary  limbs,  become  united,  by  approach- 
ing one  another  along  the  mesial  line,  so 

*  Untersuchungen  iiber  die  Bildung  des  Fluss- 
krebses. 


CRUSTACEA. 


763 


as  finally  to  constitute  a  single  continuous 
mass  only.  The  same  thing  happens  in  re- 
gard to  the  fifth  and  sixth,  which  soon  form  no 
more  than  a  single  ganglion.  As  to  the  other 
pairs  they  always  remain  completely  distinct, 
and  some  way  parted  from  one  another. 

Thus  the  study  of  the  gradual  evolution  of  the 
nervous  system  in  the  Astacus  fluviatilis,  al- 
though by  no  means  belonging  to  the  type  in 
which  this  system  is  most  completely  developed, 
presents  us  with  three  distinct  and  successive 
facts,  which  we  shall  find  reproduced  in  the 
most  perfect  manner  in  the  natural  series  of 
genera,  and  which  will  put  us  into  a  position 
to  give  a  satisfactory  explanation  of  those  very 
striking  variations  in  the  organization  which  we 
shall  encounter. 

These  are,  in  the  first  place,  the  isolated  for- 
mation of  the  nervous  centres,  independently 
one  of  another.  We  now  acknowledge  this 
independence  of  the  several  organs  at  the 
moment  of  their  appearance,  and  their  ulterior 
conjunction  is  one  of  the  most  interesting  and 
important  facts  with  which  modern  science  has 
been  enriched ;  it  constitutes  the  law  of  centri- 
petal development,  as  it  has  been  established  by 
M.  Serres. 

In  the  second  place  a  tendency  to  conjunc- 
tion by  a  motion  transversely. 

Lastly,  a  second  motion  in  the  line  of  the 
axis  of  the  body,  the  effect  of  which  is  the 
concentration  definitively  of  a  greater  or  smaller 
number  of  nervous  centres  primarily  indepen- 
dent of  one  another. 

The  Talitrus  exhibits  in  the 
most  striking  manner  the  first  of 
the  three  dispositions  which  we 
have  mentioned  from  the  mo- 
ment at  which  the  nervous  sys- 
tem appears.  In  this  genus,  in 
fact,  we  perceive  on  either  side 
of  the  median  line  a  ganglionic 
chain,  formed  by  the  conjunc- 
tion of  the  nervous  centres, 
extremely  simple  in  their  struc- 
ture, and  flattened  and  some- 
what lozenge-shaped  in  their 
outline.*  There  are  thirteen 
pairs  thus  constituted,  corres- 
ponding to  the  thirteen  seg- 
ments which  enter  into  the  com- 
position of  the  whole  body.  The 
two  nuclei  of  each  pair  com- 
municate together,  in  the  same 
manner  as  each  pair  is  con- 
nected with  that  which  succeeds, 
and  with  that  which  precedes  it, 
by  means  of  medullary  cords  in 
the  first  instance,  and  longitu-  55JjdE5 
dinal  cords  in  the  second  In  hali  '. 

all  essential  particulars  each  pair  glia :  ^  me_ 
is  a  counterpart  of  any  and  dullary  cords 
every  other  pair,  without  even  uniting  the  first 
excepting  the  cephalic  ganglion,  and  second  pair 
and  it  is  with  difficulty  that  the  of  Sanglia' 

*  Vide  Recherches  Anatomiques  snr  le  Systeme 
Nerveux  des  Crustaces,  par  M  M.  Audouin  et  Milne 
Edwards,  Annales  des  Sciences  Naturelles,  torn. 
14. 


Fig.  391. 


thoracic  pairs  are  seen  to  be  in  a  slight  degree 
larger  than  the  others.  At  a  somewhat  greater 
distance  forward  from  the  oesophagus,  too,  than 
usual,  we  observe  the  cephalic  ganglion,  which 
sends  branches  to  the  antennas  and  eyes,  and 
the  nervous  cords  by  means  of  which  it  commu- 
nicates with  the  ganglions  of  the  first  thoracic 
rings.  These  cords,  having  the  oesophagus  inter- 
posed between  them,  are  held  a  little  farther  apart 
than  the  other  branches,  which  establish  com- 
munications between  the  different  succeeding 
pairs  of  ganglions  in  the  longitudinal  direction. 

Already  in  the  Oniscus  asellus*  and  in  the  Cy- 
amus  ceti-\-  we  find  the  ganglionic  cord,  double 
in  its  middle  portions,  simplified  at  its  opposite 
extremities  in  such  wise  that  the  ganglions  of 
the  first  and  of  the  last  pairs  are  single.  This 
commencement  of  approximation  coincides  in 
other  respects  with  an  incipient  approximation 
in  the  longitudinal  direction,  for,  to  the  four- 
teen segments  of  which  the  whole  body  consists, 
we  find  no  more  than  ten  pairs  of  ganglions 
apportioned. 

This  tendency  to  centralization  is  still  more 
conspicuous  in  the  Phyllosoma.J  Here  we 
discover  the  two  cephalic  nuclei  united  by  their 
internal  angle,  without,  however,  their  state  of 
doubleness  being  thereby  obscured.  It  is  the 
same  with  the  first  pair  of  thoracic  ganglions, 
from  which  they  are  separated  by  the  whole 
length  of  the  great  oval  lamina  which  supports 
the  cephalic  appendages  and  is  traversed 
lengthwise  by  the  nervous  filaments  which 
embrace  the  oesophagus.  The  ganglions  of  the 
second  pair,  although  rudimentary,  are  still 
united  immediately,  as  are  those  of  the  third 
pair  also.  Those  of  the  six  suc- 
ceeding pairs,  on  the  contrary,  Fig.  392. 
only  communicate  by  means  of 
a  transverse  but  thick  and  -  short 
commissure,  so  that  it  gives  to 
the  connexion  established  be- 
tween the  nuclei  of  the  several 
pairs,  the  appearance  of  a  more 
immediate  conjunction  than  ac- 
tually exists.  To  conclude,  the 
abdominal  ganglions  are  perfectly 
distinct,  and  those  of  the  several 
pairs  are  only  connected  by 
means  of  extremely  slender  fila- 
ments. 

In  the  Cymothoa  the  union  of 
the  medullary  nuclei  in  the  trans- 
verse direction  is  complete,  and 
all  we  perceive  is  a  single  series 
extended  along  the  median  line 
through  the  whole  length  of  the 
body.  This  is  similar  to  the 
nervous  system  of  the  Talitrus 
conjoined  longitudinally;  with 
this  difference,  that  the  longitudinal  filaments 
uniting  the  ganglion  have  continued  distinct, 
as  if  to  testify,  by  their  doubleness,  to  the 
mode  of  formation  of  the  single  ganglionic  cord. 

*  Cuvier.    Lecons  d'Anatomie  comparee,   t.  ii. 
p.  314. 

t  Treviranus,  Vermischte  Schriften  anatomischer 
und  physiologischer  inhalts,  Band  2.   Heft  I. 

J  Audouin  et  Edwards,  loc.  cit. 

3  D  2 


764 


CRUSTACEA. 


But  it  is  more  especially  in  the  types  which 
still  ask  our  attention,  that  we  perceive  the 
system  of  centralization  pushed  yet  farther  by  the 
actual  conjunction  of  the  nuclei,  which  we  have 
hitherto  only  seen  approximated  to  one  another, 

Fig.  393. 


Nervous  system  of  the  Astacus  Marinus,  or  Sphinx 
Ligustri. 


in  consequence  of  their  gliding  or  encroaching, 
as  it  were,  upon  the  median  line. 

The  Lobster  (  Astacmmarinus )  (Jig.  393)  pre- 
sents us  with  another  step  in  the  system  of  cen- 
tralisation. Here,  in  fact,  the  longitudinal  cords 
of  communication  are  entirely  consolidated 
along  the  median  line  through  the  whole  of  the 
abdomen,  although  they  are  still  to  be  found 
double  in  the  thorax.  Moreover,  the  first  thoracic 
ganglion  (£4),  and  the  last  of  the  abdominal 
series  of  ganglions  (a6),  are  conspicuously 
formed  by  the  reunion  of  several  distinct  ner- 
vous centres,  in  the  way  we  have  already  indi- 
cated as  happening,  although  in  a  minor  degree 
and  less  perfectly,  in  the  Amphipoda  and  the 
Isopoda.  Before  we  pass,  however,  to  the  con- 
sideration of  more  complicated  systems,  we  shall 
pause  a  moment  to  describe  somewhat  at  length 
the  one  which  we  have  but  just  mentioned, 
the  more  as  it  is  among  the  number  of  those 
which  have  been  most  attentively  studied. 

The  cephalic  ganglion  (gl,jig.  393),  situated 
above  the  base  of  the  internal  antennae,  is  of  con- 
siderable size,  and  appears  to  be  simple ;  it  gives 
origin  to  five  pairs  of  nerves  and  to  two  cords, 
which  connect  it  with  the  rest  of  the  ganglionic 
nervous  system.  The  first  of  these  pairs  (o)arises 
from  its  anterior  edge :  this  is  the  optic  pair, 
which,  after  having  penetrated  the  peduncles  of 
the  eyes,  increase  in  size,  and  traverse  a  mem- 
branous diaphragm,  which  may  be  likened  to 
the  sclerotic  coat. 

The  second  pair  of  nerves  correspond  to  the 
ocular  motors;  they  run  parallel  to  the  pre- 
ceding pair,  and  are  distributed  to  the  muscles 
of  the  eyeball. 

The  third  pair  proceed  to  the  internal  anten- 
nae (6) ;  but  before  they  enter  these  appendages 
they  send  off  a  branch  to  the  muscles  which 
move  them.  A  like  ramification  is  sent  off 
from  the  principal  trunk  to  each  of  the  rings  of 
which  these  antennae  are  composed,  and  the 
nerve  ends  by  becoming  bifurcated,  in  order  to 
penetrate  the  two  filaments  in  which  the  an- 
tennae terminate. 

The  fourth  pair  of  nerves  (e)  are  distributed  to 
the  tegumentary  membranes  of  the  anterior 
extremity  of  the  animal.  Behind  the  fourth  a 
fifth  pair  is  seen  (d),  which  proceeds  anteriorly  to 
the  fourth  pair  almost  immediately  after  its 
origin,  sends  one  branch  to  the  cake-like  organ 
of  doubtful  function  which  covers  the  ear,  a 
second  branch  to  the  organ  of  hearing  itself, 
and  finally  terminates  in  a  trunk  of  considerable 
size,  which  traverses  the  external  or  second 
antenna  through  its  entire  length. 

A  sixth  pair  is  destined  to  establish  con- 
nexions between  the  cephalic  ganglion  and  the 
first  of  the  thoracic  ganglions,  after  having  sur- 
rounded the  oesophagus ;  but  instead  of  ap- 
pearing as  simple  nervous  cords  through  their 
whole  length,  as  in  types  which  we  have 
hitherto  studied,  each  of  them  presents  an 
enlargement  in  its  middle,  which  is  neither 
more  nor  less  than  a  ganglion,  from  which  there 
is  sent  off,  first,  a  nerve  that  proceeds  to  the 
mandibles  (f);  next,  a  gastric  nerve  (g),  of  large 
size,  which  gives  many  filaments  to  the  coats 
of  the  stomach,  and  finally  anastomoses  with 


CRUSTACEA. 


765 


the  corresponding  cord  of  the  opposite  side  ; 
after  this  the  two  form  a  single  nerve,  which 
by-and-by  presents  an  enlargement  having 
the  appearance  of  a  small  median  ganglion, 
and  then  remounts  upon  the  dorsal  aspect 
of  the  stomach  to  ramify  there,  and  ultimately 
to  lose  itself  upon  the  intestine  (A)-  Behind 
the  stomach  a  transverse  cord  (i)  is  seen, 
which  connects  the  two  nervous  filaments,  and 
appears  to  be  the  cord  of  communication  be- 
tween the  ganglion  of  which  mention  has  just 
been  made,  pushed  backwards,  in  the  same 
way  as  the  ganglions  themselves  have  been 
kept  apart,  to  wit,  by  the  resistance  of  the 
oesophagus,  interposed  at  the  time  when  that 
process  is  going  on  by  which  the  pairs  gene- 
rally are  approximated  in  the  course  of  the 
median  line. 

The  first  of  the  thoracic  nervous  masses  (f1) 
is  oval-shaped,  and  gives  origin  to  ten  pairs  of 
nerves,  five  of  which  issue  from  the  anterior 
aspect.  The  first  run  to  the  mandibles  and 
to  their  muscles;  the  second  to  the  auditory 
apparatus  ;  the  third  to  the  first  jaw,  the  fourth 
to  the  second  jaw  ;  the  fifth  to  the  cells  of  the 
flancs,  to  the  muscles  and  neighbouring  inte- 
guments ;  the  sixth  and  seventh  arise  from  the 
inferior  aspect  of  the  nervous  mass  to  proceed 
to  the  maxillary  feet ;  the  nerves  of  the  eighth 
pair  are  extremely  slender,  and  are  distributed 
to  the  muscles  of  the  thorax ;  the  two  succeed- 
ing pairs  belong  to  the  third  pair  of  maxillary 
extremities ;  lastly,  two  cylindrical  cords  arise 
from  the  posterior  extremity  of  this  nervous 
centre,  and  connect  it  with  the  second  thoracic 
ganglion,  giving  origin  themselves  in  their 
passage  to  a  pair  of  extremely  minute  filaments, 
which  run  to  be  distributed  to  the  muscles  of 
the  thorax. 

This  first  thoracic  nervous  mass  represents, 
therefore,  the  five  pairs  of  ganglions  which 
follow  the  mandibularring,  and  must  be  viewed 
as  resulting  from  the  concentration  of  the  five 
pairs  of  medullary  nuclei  belonging  to  the  five 
rings  which  bear  the  accessory  masticatory  or- 
gans. In  the  adult  Lobster  the  different  ele- 
mentary constituents  are  not  traceable,  and  the 
whole  mass  appears  to  be  composed  of  no  more 
than  two  ganglions  closely  connected  in  the 
median  plane;  but  in  a  species  very  nearly  allied, 
namely,  the  River-crab  (Astacus  fluviatilis), 
very  obvious  traces  of  the  existence  of  several 
medullary  nuclei  can  always  be  demonstrated 
in  its  interior.  The  five  pairs  of  ganglions 
that  follow  (<a — £6),  and  that  belong  to  the  five 
last  thoracic  rings,  have,  on  the  contrary, 
continued  distinct;  although  simple,  these 
nervous  centres  still  exhibit  manifest  indi- 
cations of  their  composition  severally  by  two 
nuclei ;  from  either  half  we  have  a  cord  of 
communication  sent  off,  similar  to  those 
which  we  have  already  pointed  out  as  exist- 
ing between  the  first  and  second  thoracic 
ganglions ;  the  whole  of  these  inter-ganglionic 
cords  are  in  contact  along  the  median  line, 
except  the  penultimate  or  antepenultimate 
pairs,  which  are  separated  from  one  another 
by  the  sternal  artery,  in  the  same  mariner  as 


those  of  the  head  are  kept  asunder  for  the  pas- 
sage of  the  oesophagus. 

Each  of  these  five  thoracic  ganglions  sends 
two  pairs  of  nerves  to  the  ambulatory  extre- 
mities which  correspond  to  them  severally. 
Of  these  two  nerves,  the  posterior  and  larger 
sends  branches  to  the  basilar  articulations  of 
the  extremities ;  the  anterior,  again,  distributes 
twigs  to  the  muscles  of  the  flancs;  the  two 
soon  anastomose,  and  form  a  single  trunk 
before  penetrating  into  the  extremity  itself, 
which  then  traverses  the  whole  limb,  send- 
ing a  branch  to  the  muscles  of  each  arti- 
culation. 

The  abdominal  ganglions  (a1— a6)  are  smaller 
than  the  preceding  ones,  and  are  connected  by 
simple  longitudinal  cords.  They  also  supply 
two  pairs  of  nerves,  the  one  destined  to  the 
muscles  of  the  abdomen,  the  other  to  the  ap- 
pendages of  the  ring  with  which  it  corresponds. 
As  in  the  thorax,  nervous  fibres,  distributed  to 
the  median  and  superior  part  of  the  abdomen, 
are  observed  proceeding  from  the  cords  which 
establish  a  communication  between  one  gan- 
glion and  another. 

The  last  ganglion  (a6),  which  appears 
to  be  made  up  of  the  medullary  nuclei  be- 
longing to  the  sixth  and  seventh  segments  of 
the  abdomen,  gives  origin  to  four  pairs  of 
nerves,  which  run  to  the  penultimate  articu- 
lation of  the  abdomen,  and  to  the  last,  which 
is  of  a  flattened  form,  and  along  with  the  ap- 
pendages of  the  former  constitutes  the  kind  of 
horizontal  oar  which  terminates  this  part  of  the 
body. 

Such  is  the  nervous  system  in  the  Lobster. 
If  we  study  it  in  the  Palemon,  we  shall  find 
precisely  the  same  elements,  but  with  a  still 
higher  degree  of  centralization,  for  the  ganglia 
of  the  three  lowest  thoracic  rings  are  conso- 
lidated into  one,  and  situated  much  forwards, 
so  that  the  nerves  to  which  they  give  origin 
have  to  pursue  a  very  oblique  course,  in  order 
to  reach  the  parts  to  which  they  are  distributed 
respectively.  The  ganglion  of  the  second  pair 
is  isolated  ;  that  of  the  first  pair  of  ambulatory 
extremities  blends  and  is  confounded  with 
that  of  the  third  pair  of  maxillary  limbs.  The 
five  anterior  pairs  of  cesophageal  ganglions,  in 
fine,  are  united  into  a  single  nervous  centre. 
There  are  consequently,  properly  speaking,  no 
more  than  four  medullary  masses  in  the  whole 
length  of  the  cephalo-thoracic  portion  of  the 
Palemon  ;  and  even  these  are  very  close  to 
one  another,  and  all  but  united,  their  longi- 
tudinal commissures  being  thick  and  simple, 
and  bearing  as  close  a  resemblance  to  constric- 
tions in  a  single  nucleus  as  to  bands  of 
communication  between  distinct  nuclei.  The 
fourth  of  these  four  ganglions  presents  a  longi- 
tudinal cleft  through  its  centre,  a  structure 
which  is  easily  explained  by  the  presence  at 
this  point  of  the  sternal  artery,  which  existed 
there  before  the  ganglia  became  conjoined  in 
the  course  of  the  median  line,  and  necessarily 
opposed  a  merely  mechanical  obstacle  to  their 
entire  union. 

In  the  Palinurus  the  whole  of  the  thoracic 


766 


CRUSTACEA. 


ganglia,  strictly  speaking,  are  united 
into  a  single  mass  of  a  greatly  elon- 
gated form,  and  presenting  a  little 
way  back,  like  the  fourth  ganglion  of 
the  Palemon,  a  cleft  for  the  trans- 
mission of  the  sternal  artery. 

The  transition 

Fig.  394.  from  the  Deca- 
poda  Macroura 
to  the  Brachyura 
takes  place  by 
the  Homola,  and 
certain  Anomou- 
ra,*  in  which  the 
constantly  in- 
creasing concen- 
tration of  the 
thoracic  nervous 
centres  coincides 
with  the  almost 
rudimentary  state 
of  the  abdominal 
ganglionic  sys- 
tem, which  is 
here  reduced  to 
a  kind  of  median 
trunk  without  en- 
largements. 

This,    too,    is 

Cephalo-thoracic    por- the       disposition 
tion  of  the  nervous  presented  by  the 
system   of  the  Pali-  nervous      system 
nurus  Vulgaris.         in   the  Carcinus 
mcenas      among 

the  Brachyura,  with  this  difference 
only,  that  the  medullary  nuclei  are 
rather  closer  to  one  another,  and 
more  intimately  connected.f  The  tho- 
racic ganglion  has  the  form  of  a  ring,  the  cir- 
cumference of  which  gives  origin  to  the  nerves  of 
the  thoracic  appendages.  The  single  abdomi- 
nal cord  is  in  its  rudimentary  state,  in  obvious 
relation  with  the  abdomen  itself,  and  therefore 
reduced  to  very  insignificant  dimensions. 

It  is  in  the  Maja,|  in  fine  (Jig.  395),  that  the 
nervous  system  is  found  in  its  highest  degree  of 
centralization ;  for  the  elements  of  which  the 
two  masses  there  encountered  are  composed,  are 
so  intimately  conjoined,  that  no  trace  can  be 
found  of  their  ever  having  existed  indepen- 
dently, although  among  neighbouring  genera 
several  of  them  may  still  be  discovered  isolated- 
ly.  The  cephalic  ganglion  (a)  is  a  sufficiently 
faithful  counterpart  of  that  of  the  Lobster. 
The  nervous  cords  (g)  which  connect  this  first 
portion  of  the  system  with  the  thoracic  portion 
also  present  the  same  arrangement  as  in  the  Lob- 
ster ;  there  are  similar  mandibular  nerves,  a  like 
gastric  pair,  the  same  transverse  band  (g  )  behind 
the  oesophagus,  &c.  But  the  thoracic  ganglion 
(/),  instead  of  the  ring  which  it  presents  in  the 

*  Vide  Rech.  sur  Torganiz.  et  la  classific.  des 
Crustaces  Decapodes  par  M.  Milne  Edwards  •  An- 
nales  des  Sciences  Naturelles,  t.  xv. 

t  Cuvier,  Legons  d'Anatomie  Comparee,  t.  ii.  p. 

$  Audouin  et  Edwards,  loc.  cit. 


Fig.  395. 


Nervous  system  of  the  Maja  Squinado. 
a,  cephalic  ganglion ;  b,  optic  nerves ;  c,  oculo- 
motor nerves ;  d,  nerves  of  the  antennulae ;  e, 
fourth  pair  of  nerves  belonging  to  the  integuments  j 
ft  nerves  of  the  exterior  antennae  •  g,  medullary 
cords  uniting  the  cephalic  and  thoracic  ganglions } 
g',  transverse  cord ;  h,  mandibular  ganglion  ;  h', 
small  nerve  belonging  to  the  muscles  of  the 
mandible ;  i,  stomato-gastric  nerve  ;  k,  lateral 
branches  of  the  stomato-gastric  nerves  j  I,  tho- 
racic ganglion ;  m,  nerves  of  the  maxillae ;  n, 
nerves  of  the  first  pair  of  legs ;  o,  abdominal 
nerve ;  p,  cells  of  the  llancs  ;  q,  arch  of  the 
flancs. 

Carcinus  mcenas,  here  appears  as  a  solid  circu- 
lar and  flattened  nucleus  giving  origin  to  the 
whole  of  the  nerves  of  the  thorax  and  abdo- 
men, which  radiate  from  it  to  the  number  of 
nine  pairs,  and  one  azygous  nerve  situated  in  the 
median  plane.  There  is  nothing  very  remarkable 
in  the  distribution  of  these  nerves,  unless  it  be 
thatseveral  pairs,and  amongthe number  the  first 
and  second,  are  distributed  simultaneously  to 
several  rings,  which  proclaims  that  in  the 
species  which  engages  us  the  work  of  con- 
centration has  extended  from  the  ganglions  to 
the  nervous  cords. 

Any  farther  detail  in  addition  to  what  has 
now  been  said  would  contribute  little  to  our 
essential  knowledge  of  the  nervous  system. 
We  have  traced  it  from  its  commencement  in 


CRUSTACEA. 


767 


a  series  of  independent  centres,  and  we  have 
seen  these  becoming  successively  conjoined  in 
a  greater  and  greater  degree,  as  if  in  obedience 
to  a  law  of  attraction,  whose  tendency  was  to 
collect  these  various  nuclei  from  every  part  of 
the  body  towards  a  common  centre.  This  dis- 
position to  centralization  has,  in  its  turn,  given 
a  satisfactory  explanation  of  the  most  remark- 
able differences  observed  in  the  disposition  of 
the  ganglions  and  of  the  nervous  cords 
among  the  different  types  of  the  class,  however 
dissimilar  these  may  be  one  from  another. 
We  may,  therefore,  here  conclude,  as  has  been 
done  already  in  my  work  especially  devoted  to 
this  subject,  that  the  nervous  system  of  the 
Crustacea  consists  uniformly  of  medullary 
nuclei  (ganglions),  the  normal  number  of' 
which  is  the  same  as  that  of  the.  members  or 
rings  of  the  body,  and  that  all  the  modifica- 
tions encountered,  whether  at  different  periods 
of  the  incubation,  or  in  different  species  of  the 
series,  depend  especially  on  the  approximation, 
more  or  less  complete,  of  these  nuclei,  (an  ap- 
proximation which  takes  place  from  the  sides 
towards  the  median  line  as  well  as  in  the  longi- 
tudinal direction,)  and  to  an  arrest  of  develop- 
ment occurring  in  a  variable  number  of  the 
nuclei. 

In  a  paper  upon  the  nervous  system  of  the 
Lobster  recently  published,*  Mr.  Newport 
mentions  an  interesting  fact  hitherto  overlooked 
by  anatomists.  He  found  that  the  double 
ganglionic  chain  of  this  Crustacean  is  composed 
of  two  orders  of  fibres,  forming  distinct  and 
superposed  fasciculi  or  columns,  which  the 
author  designates  columns  of  sensation  and  of 
motion,  following  the  analogy  which  he  be- 
lieved he  had  traced  between  these  fasciculi 
and  the  anterior  and  posterior  columns  of  the 
spinal  cord  of  the  higher  animals.  The  fas- 
ciculi here  indicated  are  but  indistinct  in  the 
interganglionic  cords,  but  become  extremely 
apparent  in  the  ganglions  themselves,  for  these 
enlargements  belong  exclusively  to  the  inferior 
or  sensitive  fasciculi,  and  the  superior  or  motor 
fasciculi  pass  over  their  dorsal  surface  without 
penetrating  their  substance  at  all. 

Before  going  on  to  the  study  of  those  organs 
the  object  of  which  is  the  application,  if  we 
may  be  allowed  the  expression,  of  the  nervous 
system  to  the  perception  of  the  existence  of 
outward  objects,  and  of  those  in  which  the 
reaction  designated  volition  is  immediately 
effected,  that  is  to  say,  the  organs  of  the  senses 
and  the  muscles,  it  may  be  as  well  to  say  a 
word  upon  the  general  functions  of  the  nervous 
system  itself  in  its  different  parts.  The 
experiments  made  by  M.  Audouin  and  me, 
with  a  view  to  solve  the  principal  problems 
which  may  be  proposed  on  this  subject,  have 
confirmed  the  inductions  to  which  we  had  been 
led  by  views  arrived  at  a  priori  wholly  from 
anatomical  researches,  of  which  the  preceding 
may  be  regarded  as  the  summary.  Tims : — 

*  On  the  Nervous  System  of  the  Sphinx  ligustri, 
&c.  by  G.  Newport,  Philos.  Transact.  1834,  pt.  ii. 
p.  406. 


Istly,  The  nervous  is  the  system  which  en- 
tirely presides  over  the  sensations  and  motions. 
2dly,  The  nervous  cords  are  merely  the 
organs  of  transmission  of  the  sensations  and 
of  volition,  and  it  is  in  the  ganglions  that  the 
power  of  perceiving  the  former  and  of  pro- 
ducing the  latter  resides.  Every  organ  sepa- 
rated from  its  nervous  centre  speedily  loses  all 
motion  and  sensation. 

3dly,  The  whole  of  the  ganglions  have 
analogous  properties  :  the  faculty  of  determin- 
ing motions  and  of  receiving  sensations  exists  in 
each  of  these  organs;  and  the  action  of  each 
is  by  so  much  the  more  independent  as  its 
development  is  more  isolated.  When  the 
ganglionic  chain  is  nearly  uniform  through  its 
whole  length,  it  may  be  divided  without  the 
action  of  the  apparatus  being  destroyed  in 
either  portion  thus  isolated, — always  under- 
stood, that  both  are  of  considerable  size; 
because  when  a  very  small  portion  only  is 
isolated  from  the  rest  of  the  system,  this 
appears  too  weak,  as  it  were,  to  continue  its 
functions,  so  that  sensibility  and  contractility 
are  alike  speedily  lost.  But  when  one  portion 
of  the  ganglionic  chain  has  attained  a  develop- 
ment very  superior  to  that  of  the  rest,  its 
action  becomes  essential  to  the  integrity  of  the 
functions  of  the  whole. 

It  must  not  be  imagined,  however,  from 
this  that  sensibility  and  the  faculty  of  exciting 
muscular  contractions  are  ever  completely  con- 
centrated in  the  cephalic  ganglions,  and  it 
seems  to  us  calculated  to  convey  a  very 
inaccurate  idea  of  the  nature  and  functions  of 
these  ganglions  to  speak  of  them  under  the 
name  of  brain,  as  the  generality  of  writers  have 
been  led  to  do,  seduced  by  certain  inconclu- 
sive analogies  in  point  of  form  and  position. 
It  is  nevertheless  to  be  remarked  that  in  these 
animals  an  obscure  tendency  to  the  centra- 
lization of  the  nervous  functions  is  observable 
in  the  anterior  portion  of  the  ganglionic  chain ; 
because  if  in  the  Lobster,  for  instance,  it  he 
divided  into  two  portions,  as  nearly  equal  as 
possible,  by  severing  the  cords  of  communica- 
tion between  the  ganglions  belonging  to  the 
first  and  second  thoracic  rings,  sensibility,  and 
especially  mobility,  are  much  more  quickly 
lost  in  the  posterior  than  in  the  anterior  half; 
and  this  disproportion  is  by  so  much  the  more 
manifest  as  the  division  is  performed  more 
posteriorly;  still  there  is  a  great  interval 
between  this  first  indication  and  the  concen- 
tration of  the  faculties  of  perception  and  of 
will  in  a  single  organ — the  brain,  of  which 
every  other  portion  of  the  nervous  system  then 
becomes  a  mere  dependency. 

B.  Organs  of  the  senses. — Do  the  five 
senses  exist,  and  to  what  degree  of  development 
have  they  attained  in  the  Crustacea?  Such 
is  the  question  we  have  now  to  consider,  and 
which  we  shall  sometimes  find  ourselves  in  a 
condition  to  answer  from  the  simple  inspection 
of  the  various  organs  of  special  application. 

Thus  we  discover  almost  at  once  that  the 
sense  of  general  touch  is  obtuse,  and  can 
convey  to  the  animal  no  other  but  confu-«.-d 


768 


CRUSTACEA. 


notions  of  the  existence  and  of  the  resistance 
of  the  bodies  with  which  it  finds  itself  in 
immediate  relationship  by  its  external  surface. 
To  be  satisfied  of  this,  it  is  enough  to  consider 
for  a  moment  the  hard  and  unyielding  nature 
of  the  general  tegumentary  envelope  over  every 
point  of  the  body  except  the  articulations, — 
parts  which  on  other  grounds  are  obviously 
inadequate  to  exercise  any  sense  whatever. 

Nevertheless,  in  front  of  the  head  there  are 
certain  special  organs  which  all  the  observa- 
tions I  have  had  an  opportunity  of  making 
upon  the  organization  of  these  animals  lead 
me  to  regard  as  parts  more  particularly  destined 
to  be  'the  seat  of  the  sense  of  touch.  These 
organs  are  the  antennae, — those  slender  fila- 
ments, possessed  of  a  great  degree  of  flexibility, 
of  motility,  and  of  sensibility.  M.  de  Blain- 
ville  was  led  to  regard  these  organs  as  the 
seat  of  the  sense  of  smell ;  but  direct  and 
conclusive  experiment  has  satisfied  us  that  the 
destruction  of  the  antennae  has  no  influence 
whatever  on  the  exercise  of  the  sense  of 
smell :  and  we  are  on  the  same  grounds  in- 
duced to  believe  them  destined  to  the  exer- 
cise of  the  sense  of  touch  of  considerable 
delicacy,  unless  we  would  imagine  them  as 
the  instruments  of  some  quite  peculiar 
sense  the  existence  of  which  would  be  purely 
hypothetical. 

The  number  and  disposition  of  these  organs 
varies  extremely.  Some  of  the  Crustaceans 
at  the  very  bottom  of  the  series  are  wholly 
without  antennae,  or  are  furnished  with  them 
in  a  merely  rudimentary  state.  Some  species 
have  no  more  than  a  single  pair ;  the  normal 
number,  however,  is  two  pairs.  In  speaking 
of  the  tegumentary  skeleton,  we  have  said  to 
which  of  the  rings  these  appendages  belong ; 
we  shall  only  say  farther  here,  that  they  may 
be  inserted  on  the  superior  or  on  the  inferior 
surface  of  the  head  according  to  the  respective 
development  of  the  different  pieces  of  which 
this  segment  is  composed.  They  do  not  differ 
less  widely  in  their  form  and  composition,  and 
under  this  double  point  of  view  present  modi- 
fications analogous  to  those  which  we  have 
specified  as  occurring  in  the  extremities. 

The  Crustaceans,  like  almost  all  other  animals, 
make  a  selection  of  matters  in  especial  relation--- 
ship  with  the  state  of  their  organs  of  nutrition; 
they  must  therefore  be  endowed  with  the 
sense  of  taste.  With  reference  to  the  seat 
of  this  faculty,  which  perchance  is  the  mo- 
dification of  sensibility  the  least  remote  from 
the  sense  of  touch,  it  appears  to  reside  in  the 
Crustacea,  as  it  does  obviously  in  the  majority 
of  animals,  in  that  portion  of  the  tegumen- 
tary membrane  which  lines  the  interior  of 
the  mouth  and  oesophagus ;  but  the  dispo- 
sition of  the  parts  there  presents  no  peculiarity 
worthy  of  especial  notice. 

The  Crustaceans  perceive  the  existence  of 
bodies  at  a  distance  by  the  medium  of  odorous 
particles  emitted  from  these  bodies.  Many 
of  the  know  n  habits  of  these  animals,  and  the 
certainty  with  which  they  are  attracted  by 
baits  placed  in  close  traps  from  which  the 


light  is  excluded,  do  not  allow  us  to  entertain 
any  doubts  upon  this  point;  but  we  are  reduced 
to  conjecture  when  we  are  required  to  point 
out  the  precise  seat  of  the  organ  of  smelL 
The  horny  appendages  named  antennae  are 
certainly  not  it,  as  M.  de  Blainville  imagined  ;* 
and  the  opinion  of  M.  Rosen  thal,f  who  ascribes 
the  function  to  a  cavity  which  he  discovered 
at  the  base  of  the  first  pair  of  antennas,  requires 
to  be  supported  by  direct  experiment. 

Hearing,  at  least  in  a  great  number  of 
species,  resides  in  a  particular  apparatus  per- 
fectly well  known.  It  (fg.  396) 
is  found  in  the  inferior  surface  Fig.  396.. 
of  the  head,  behind  the  an- 
tennae of  the  second  pair,  or 
upon  the  first  basilar  articu- 
lation of  these  antennae  them- 
selves} (fg.  396,  a).  It  con- 
sists in  the  River-crab  of  a  small 
bony  tubercle  pierced  at  its 
summit  by  a  circular  opening,  upon  which  is 
stretched  a  thin  elastic  membrane,  which 
Scarpa  has  compared  to  that  of  the  tym- 
panum, or  of  the  fenestra  ovalis  of  the  ves- 
tibule in  the  higher  animals.  Behind  this 
membrane  there  is  a  membranous  vesicle 
filled  with  fluid,  into  which  a  branch  of  the 
antennary  nerve  is  observed  to  plunge.  Above 
this  organ  there  is  another  of  a  glandular 
appearance,  the  intimate  relations  of  which 
with  the  apparatus  we  have  just  described 
might  lead  to  the  belief  that  it  was  not  un- 
connected with  the  sense  of  hearing.  In  the 
Palinurus  it  communicates  with  an  opening 
which  is  pierced  through  the  centre  of  the 
membrane  that  closes  the  auditory  tubercle  in 
front. 

The  membrane  in  the  greater  number  of  the 
Brachyura  is  replaced  by  a  small  moveable  os- 
seous disc,  which  in  the  Maja  and  some  others 
presents  a  pretty  broad  bony  plate  (  fig.  397)  at 

Fig.  397. 


Auditory  disc  of  (he  Maja  Squinado  separated  from 
the  rest  of  the  apparatus. 

its  posterior  edge,  detaching  itself  at  right 
angles  and  running  upwards  towards  the  glan- 
dular organ  already  mentioned.  Near  its 
base  this  lamellar  prolongation  is  pierced 
with  a  large  oval  opening,  over  which  there 
is  stretched  a  thin  and  elastic  membrane 
which  might  be  named  the  internal  auditory 

*  Principes  d'anatomie  comparee,  t.  i.  p.  338  et 
339. 

t  Reil's  Archiv.  und  Treviranus's  vermischte 
Schriften,  2ter  Band.  2tes  Heft. 

$  Minasi,  Dissertazioni  di  timpanetti  del'udito 
scoperti  nel  Granchio  paguro.  Scarpa,  De  structura 
fenestrae  rotundas,  &c.  Anat.  observ.  4to.  Mutin. 
1772;  Anat.  Disq.  de  Auditu  et  Olfactu,  fol.Ticin. 
1789.  Cuvier,  Lemons  d'anatomie  comparee,  t.  ii. 
Milne  Edwards,  Histoire  naturelle  des  Crustacea^ 
t.  i.  p.  123. 


CRUSTACEA. 


membrane,  near  to  which  the  auditory  nerve 
appears  to  terminate.  This  small  bony  lamina, 
which  is  moved  by  minute  muscular  fasciculi, 
recals  in  some  measure  the  stapes  of  the 
human  ear.  Under  the  anterior  edge  of  the 
external  opening  of  the  ear  which  is  closed 
by  this  bony  disc  (Jig.  398  ),  is  seen  a  small 

Fig.  398. 


Audi tory  apparatus  of  the  Maja  in  its  natural  position, 
showed  by  removing  the  carapace  and  the  vis- 


lamina  parallel  to  the  internal  auditory  mem- 
brane ;  and  when  the  anterior  muscle  of  the 
ossiculum  contracts  so  as  to  bring,  in  a  slight 
measure,  the  whole  of  this  little  apparatus 
forwards,  the  membrane  of  which  mention  has 
just  been  made  rests  upon  the  bony  prolonga- 
tion, and  is  made  tense  in  a  continually  in- 
creasing degree ;  and  from  the  experiments  of 
M.  Savart  we  know  that  all  increase  in  the 
tension  of  thin  membranes  lessens  their  dispo- 
sition to  be  thrown  into  vibration  ;*  consequently 
in  undergoing  such  a  modification,  the  kind  of 
tympanum  described  must  serve  to  moderate 
sounds  of  too  great  intensity,  in  their  passage 
to  the  acoustic  nerve.  In  other  respects  it 
is  evident  that  the  mechanism  described  pre- 
sents the  most  forcible  analogies  with  what 
we  observe  in  the  human  ear,  and  that  the 
ossiculum  auditus  here  stands  in  lieu  of  the 
chain  of  small  bones  which  exists  in  the  organ 
of  hearing  arrived  at  its  highest  point  of  de- 
velopment. 

The  presence  of  the  long  rigid  stem  formed 
by  the  antennae  of  the  second  pair,  and  its 
immediate  communication  with  the  organ  of 
hearing  cannot,  it  might  have  been  presumed 
CL  priori,  be  unimportant  as  regards  the  per- 
ception of  sound ;  and  this  is  found  to  be  the 
case  in  fact;f  for  from  the  beautiful  experiments 
of  M.  Savart  we  learn  that  the  addition  of  a 
rigid  stem  is  sufficient  to  render  certain  vibra- 
tions perceptible,  which,  without  this  kind  of 
conductor,  are  altogether  inappreciable. 

The  auditory  apparatus  of  the  Crustacea  con- 
sequently consists  essentially  of  a  cavity  full 
of  fluid,  to  which  a  nerve  adapted  to  perceive 
sonorous  impulses  is  distributed ;  which  ele- 
mentary and  essential  apparatus  is  assisted  in 

*  Recherches  sur  les  usages  de  la  membrane  du 
tympan  et  de  1'oreille  externe,  Journal  de  Physio- 
logic de  Magendie,  t.  iv. 

t  Strauss- Drkickheim,  Considerations  generales 
sur  1'anatomie  des  Crustaces,  p.  419. 


its  functions  by  certain  special  organs,  such  as 
elastic  membranes  and  rigid  stems,  calculated 
by  their  nature  to  vibrate  under  the  action  of 
sonorous  undulations. 

We  have  still  to  speak  of  the  organ  of  sight. 
With  the  exception  of  certain  parasitic  species* 
the  faculty  of  perceiving  the  existence  of  ex- 
ternal objects  by  the  medium  of  light  is  pos- 
sessed by  the  whole  class  of  Crustacea,  and  is 
found  dependent  on  a  particular  organ  of  a  con- 
siderably complicated  structure  situated  in  the 
head,  towards  its  anterior  aspect,  superiorly 
or  on  the  sides.  Even  the  exception  which 
has  been  made  is  merely  accidental,  as  it  were  ; 
for  in  the  earliest  periods  of  their  existence 
the  parasitic  Crustacea  also  possess  eyes,  and 
it  is  only  as  an  effect  of  the  kind  of  meta- 
morphosis which  these  animals  experience  that 
the  organs  of  vision  disappear. 

The  eyes  in  insects  are  simple  or  compound ; 
but  this  division  is  inadequate  to  give  us  any 
proper  idea  of  the  various  forms  under  which 
these  organs  present  themselves  to  our  observa- 
tion in  the  Crustacea,  and  into  the  study  of 
which  we  shall,  therefore,  enter  with  some 
attention  to  detail.* 

The  least  complex  form  under  which  the 
eyes  of  the  Crustacea  occur  is  that  which  has 
been  designated  under  the  name  of  Stemmuta, 
smooth  eyes  or  simple  ei/es.  The  structure  of 
these  does  not  differ  essentially  from  that  ob- 
served among  the  higher  animals.  We  distin- 
guish, in  the  first  place,  a  transparent  cornea, 
smooth  and  rounded,  which  is  in  fact  nothing 
more  than  the  general  tegumentary  mem- 
brane modified  in  a  particular  point.  The 
internal  aspect  of  this  cornea  is  in  immediate 
contact  with  a  crystalline  lens,  generally  of  a 
spherical  form  ;  this,  again,  is  in  contact  poste- 
riorly with  a  gelatinous  mass  analogous  to  the 
vitreous  humour,  and  this  mass  in  its  turn  is 
in  contact  with  the  extremity  of  the  optic 
nerve.  A  layer  of  pigmentum  thick  and 
of  a  very  deep  colour,  envelopes  the 
whole  of  these  parts,  lining  the  internal  wall 
of  the  globe  of  the  eye  up  to  the  point  at 
which  the  cornea  begins  to  be  formed  by  the 
thinning  of  the  tegumentary  envelope  become 
transparent.  This  is  what  we  observe  in  a 
limited  number  of  the  Crustacea,  among  which 
we  may  mention  the  Limuli,  the  Cyamee,  and 
the  Apus.  The  number  of  these  simple  eyes 
never  exceeds  two  or  three. 

A  step  in  the  complexity  of  the  organ  of 
sight  is  presented  to  us  in  the  eyes  of  the 
Nebalia,  Branchipus,  and  Daphnia.  In  these, 
behind  the  cornea,  which  externally  presents 
no  trace  of  divisions,  a  variable  number  of 
small  crystalline  lenses  and  vitreous  humours 
are  found,  each  included  in  a  kind  of  sac  or 
pigmentary  cell,  and  terminating  by  coming 

*  On  the  structure  of  the  eyes,  vide  Swammer- 
dam,  in  the  Collection  Academique,  partieetrangere, 
t.  v.  p.  170.  Cavolini,  Memoria  sulla  generazione 
dei  Pesci  et  Dei  Granchi.  Strauss,  op.  cit. 
J.  Midler,  Zur  vergleichenden  Physiologic  des 
Gesichtsinncs  etc.  Ann.  des  Sciences  Naturelles, 
t.  17.  Milne  Edwards,  Hist.  Nat.  des  Crustaces, 
t.  i.  p.  114. 


770 


CRUSTACEA. 


immediately  into  contact  with  the  optic  nerve. 
These  eyes  are  obviously  made  up  by  the  con- 
junction of  several  stemmata  under  a  common 
cornea.  The  Apus,  besides  its  pair  of  simple 
eyes,  presents  another  compound  pair,  behind 
and  at  some  distance  from  these. 

The  Amphihoe  Prevostii  and  some  other 
Edriophthalmians  present  the  transition  from 
the  form  last  described  to  that  of  truly  com- 
pound eyes,  having  distinct  facets.  The  cornea 
in  these  is  formed  of  two  transparent  laminae, 
the  external  of  which  is  smooth  and  without 
divisions,  whilst  the  internal  is  divided  into 
a  variable  number  of  hexagonal  facets,  each 
of  which  is  a  distinct  cornea,  superposed  upon 
such  a  conical  crystalline  lens,  as  we  shall 
have  occasion  immediately  to  describe  when 
speaking  of  compound  eyes  properly  so  called, 
or  eyes  with  simple  facets. 

In  these  the  two  membranes,  external  and 
internal,  the  union  of  which  constitutes  the 
cornea,  present  simultaneously  the  division 
into  facets,  each  of  which  forms  anteriorly  an 
ocular  compartment  proper  to  it.  These  facets, 
always  hexagonal  in  insects,  are  of  various 
forms  in  the  Crustacea :  thus  in  the  Astacus 
fluviatilis,  the  Peneae,  the  Galatheae,  and 
the  Scyllari,  they  are  square  (fig.  399),  whilst 
the  Paguri,  the  Phyllosoma,  the 
Fig.  399.  Squillae,  the  Gebiae,  the  Calli- 
anassae,  and  the  Crabs,  have  them 
hexagonal  (fg.  400).  The  crys- 
talline that  succeeds  them  imme- 
diately is  of  a  conical  form,  and 
is  followed  by  a  vitreous  humour 
Fig.  400.  having  the  appearance  of  a  gelati- 
nous filament,  adhering  by  its  base 
to  the  optic  nerve.  Each  of  the 
columns  thus  formed  is,  more- 
over, lodged  within  a  pigmentary 
cell,  which  likewise  covers  the 
bulb  of  the  optic  nerve.  But 
the  most  remarkable  circumstance  is,  that 
the  large  cavity  within  which  the  whole  of 
these  parallel  columns,  every  one  of  which 
is  in  itself  a  perfect  eye,  are  contained,  is 
closed  posteriorly  by  a  membrane,  which  ap- 
pears to  be  neither  more  nor  less  than  the 
middle  tegumentary  membrane,  pierced  for 
the  passage  of  the  optic  nerve ;  so  that  the 
ocular  chamber  at  large  results  from  the  sepa- 
ration at  a  point  of  the  two  external  layers 
of  the  general  envelope. 

Fig.  401. 


Longitudinal  section  of  the  Eye  of  the  Lobster. 

The  gelatinous  or  vitreous  elongated  pro- 
cesses which  succeed  the  conical  crystallines 
have  been  looked  upon  by  several  anatomists 
as  ramifications  of  the  optic  nerve ;  but  we 
do  not  imagine  that  they  are  so  in  reality. 
In  the  Lobster,  for  instance,  we  have  even 
seen  the  surface  of  the  bulb  isolated  from  the 
masses  in  question,  divided  into  compartments. 


Fig.  402. 


corresponding  to  those  of  the  cornea  itself, 
and  lined  with  a  layer  of  pigmentum  perfectly 
distinct. 

The  most  remarkable  modification  of  facetted 
eyes  consists  in  the  presence  of  a  kind  of  sup- 
plementary lens,  of  a  circular  shape  and  set 
within  the  cornea  in  front  of  each  proper  crys- 
talline lens  (fg.  402).  These  small  lenticular 
bodies  exist  independently,  and 
are  perfectly  distinct  from  the 
small  corneal  facets.  In  some 
cases  they  might  be  mistaken 
(in  the  Idoteae,  for  example, 
where  they  may  be  perceived 
singly,  and  with  their  distinct 
circular  forms),  and  the  incau- 
tious observer  led  to  conclude  that  the  cor- 
neal facets  are  merely  these  lenticular  bodies 
so  much  enlarged  that  their  hexagonal  or 
square  forms  result  from  their  agglomeration 
in  a  point;  but  there  are  Crustacea,  such  as 
the  Callianassse,  in  which  these  two  elements 
of  the  external  cornea  may  be  perfectly  dis- 
tinguished, the  lenticular  body  being  of  insig- 
nificant dimensions  and  occupying  the  centre 
of  the  corneal  facet  only  (Jig.  402).  In  general, 
howeve'r,  the  diameter  of  the  lenticular  body 
is  equal  to  that  of  the  corneal  facet  itself,  so 
that  their  edges  blend.  Farther,  the  lenticular 
bodies  are  most  commonly  evolved  in  the  sub- 
stance of  the  cornea;  but  there  are  cases  in 
which,  under  favourable  circumstances,  they 
may  be  detached  from  it. 

Although  the  existence  of  these  different 
modifications  must  not  be  understood  as  being 
exclusive,  inasmuch  as  there  are  certain  Crus- 
tacea which  exhibit  more  than  one  of  them  at 
the  same  time,  for  instance,  stemmata  and 
compound  eyes,  the  latter  only  are  the  species 
of  visual  organ  encountered  in  the  great  ma- 
jority of  cases.  Their  general  number  is  two ; 
but  these  are  occasionally  united,  so  as  to 
form  a  single  mass,  and  make  the  animal 
appear  at  first  sight  as  if  it  had  but  a  single 
eye.  This  peculiarity  of  organization  can  even 
be  followed  in  the  Daphniae,  in  the  embryo 
of  which  the  eyes  are  first  seen  isolated ;  with 
the  progress  of  the  development,  however, 
they  are  observed  gradually  to  approach  each 
other,  and  finally  to  become  united.  Stemmata 
are  always  immoveable  and  sessile ;  the  com- 
pound eyes  with  smooth  corneae,  however, 
although  in  the  majority  of  cases  they  present 
the  same  disposition,  now  and  then  occur 
moveable :  sometimes  they  are  supported  by  a 
pedicle,  moveable  in  like  manner,  and  pro- 
vided with  special  muscles.  The  eyes  with 
facets  present  the  same 
modifications,  and  even 
supply  important  charac- 
ters in  classifying  these 
animals :  thus  in  the 
Edriophthalmia  the  eyes 
are  always  immoveable 
and  sessile,  (fg.  403,) 
whilst  in  the  Decapo- 
da  and  the  Stomapoda 
(fig-  404)  they  are  sup- 
ported upon  moveable 


Fig.  403. 


CRUSTACEA. 


771 


Fig.  404. 


Fig.  405. 


stems  of  very  various  lengths,  and  which  every 
consideration  leads  us  to  view  as  the  limbs  or 
appendages  of  the  first  cephalic  ring.  It  some- 
times even  happens  (Jig.  404)  that  in  these 
animals,  between  the  outer  edge  of  the  cara- 
pace and  the  base  of  the  antennae,  there  occurs 
a  furrow  or  cavity  within  which  the  eyes  may 
be  withdrawn  or  laid  flat,  so  as  to  be  out  of 
the  way  of  injury ;  this  groove  or  cavity  is 
generally  spoken  of  under  the  name  of*  the 
orbit. 

§  3.  Apparatus  of  Nutrition. 

In  the  study  of  this  apparatus  we  shall  have 
to  consider  successively  the  organs  of  digestion, 
of  circulation,  of  respiration,  and  of  secretion. 

A.  Apparatus  of  digestion.  —  The  organs 
concerned  in  the  digestion  of  the  food  among 
the  Crustacea  may  be  divided  into  three 
orders,  according  to  the  functions  they  fulfil, 
to  wit,  1st,  the  apparatus  for  the  prehension 
and  mastication  of  the  food;  2nd,  the  alimen- 
tary canal ;  3rd,  the  various  secreting  organs 
associated  with  the  intestine. 

The  Crustacea  are  divided  into  two  grand 
sections  in  conformity  with  their  habits  and 
the  nature  of  their  food : —  the  masticators, 
which  generally  live  apart  from  their  prey, 
pursue  it,  and  seize  it  in  proportion  as  they 
are  admonished  by  their  wants  or  appetite  to 
do  so;  and  the  suckers,  considerably  fewer  in 
number,  and  which  in  their  state  of  perfect 
growth  live  almost  invariably  attached  to  their 
prey  without  executing  any  other  motions  than 
such  as  are  performed  by  the  latter. 

The  masticating  Crustacea  being  the  highest 
in  point  of  organization,  we  shall  commence 
our  description  with  them,*  and  we  shall  even 
select  for  our  particular  consideration  the  spe- 
cies among  these  which  have  the  class  of 
organs  about  to  be  investigated  of  the  most 
complex  structure,  namely,  the  Decapoda 
brachyura.  In  these  animals  the  mouth  is 
constantly  situated  on  the  inferior  surface  of 
the  cephalic  portion  of  the  body.  Two  lips 
close  it  anteriorly  and  posteriorly  ;  the  upper 
lip  or  labrum  (a,  fig-  405)  is  a  median  piece  in 
the  form  of  a  simple  fold,  and  the  lower  lip 
or  languette  (c)  is  for  the  most  part  bifid.  Be- 
tween these  two  pieces  and  on  their  sides  are 
the  mandibles,  (jig.  406,)  appendices  of  the 
fourth  cephalic  ring,  modified  so  as  to  serve  for 
mastication.  As  in  the  whole  tribe  of  articu- 

*  On  this  subject  consult  Savigny  Memoires  sur 
les  Animaux  sans  Vertebres,  Ire  fascicule ;  La- 
treille,  Hist.  Nat.  des  Crustaces  et  Insectes,  &c.  ; 
Cuvier,  Regue  Animal ;  Desniarest,  Considerations 
sur  les  Crustaces  ;  Milne  Edwards,  Hist.  Nat.  des 
Ciustaces,  t.  i.  p.  61. 


Masticatory  Organs  of  tJie  Phyllosomu. 

a,  upper  lip  j  b,  mandibles  j  c,  lower  lip  j 

(I,  maxillae. 

lated  animals,  these  organs  act  laterally,  and  not 
upwards  and  downwards  in  the  line  of  the  axis 
of  the  body  as  in  the  vertebrate  series  univer- 
sally.   They  do  not  vary 
Fig.  406.  much  in  point  of  form 

among  the  Decapoda; 
in  almost  every  one  of 
these  they  are  seen  pos- 
sessed of  a  principal 
part  terminated  by  a 
cutting  edge,  or  a  sur- 
face adapted  for  tritu- 
ration;  and  an  appendage  which  appears  to 
fasten  the  food  and  keep  it  steady  during 
the  process  of  mastication.  The  mandible 
itself,  which  is  of  extreme  hardness,  appears 
to  be  neither  more  nor  less  than  the  basilar 
piece  of  the  member  or  appendage,  of  great 
strength  and  toothed.  The  articulated  palp 
which  it  supports,  in  this  mode  of  viewing 
the  structure,  would  turn  out  to  be  a  mere 
continuation  of  the  stem  (tige),  and  not  a 
proper  palp,  as  its  name  seems  to  imply, 
but  which  it  has  only  acquired  from  its  resem- 
blance to  the  appendage  to  which  the  term  of 
right  belongs. 

Such  is  the  structure  of  the  mouth  among 
a  certain  number  of  the  inferior  Crustacea;  but 
among  those  to  which  we  now  turn  our  atten- 
tion, we  remark  an  addition  of  as  many  as  five 
pairs  of  modified  appendages  situated  behind 
the  under  lip,  and  all  subservient  to  the  pre- 
hension and  the  mastication  of  the  food.  The 
two  first  (figs.  406  and  407)  are  the  most  con- 
stant; and  even  when  we  get  low  in  the  series, 
and  they  have  lost  their  special  functions,  they 
can  still  be  traced,  although  of  course  only  in 
a  rudimentary  state.  When  well  developed 
they  are  without  palps  and  are  designated 
by  the  name  of  jaws.  The  three  other  pairs, 
again,  soon  cease  to 
appear  as  part  of  the 
implements  of  digestion, 
in  order  to  show  them- 
selves among  the  instru- 
ments of  locomotion ; 
sometimes,  however, 
they  seem  to  serve  for 
both  kinds  of  function, 
a  circumstance  which  has 


Fig.  407. 


772 


CRUSTACEA. 


led  to  their  ordinary  denomination  of  maxil- 
lary limbs  or  feet  (figs.  408,  409,  410.) 


and  in  the   Phyllo- 


Fig.  408. 


Fig.  409. 


amounts  to  three  pairs, 
soma  to  two  pairs  only. 

To  conclude,  the  Limuli,  a  group  of  Crusta- 
ceans of  the  most  singular  conformation,  are  at 
the  bottom  of  the  scale  in  this  respect;  for  in 
them  (Jig.  411)  the  anterior  ambulatory  extre- 
mities themselves  surround  the  mouth,  and 
their  basilar  articulations  perform  the  office  of 
jaws. 

The  organs  of  which  we  have  just  made 
mention,  are,  according  to  the  modifications 
they  undergo,  adapted  in  a  more  or  less  espe- 
cial manner  to  seize,  to  hold  fast,  and  to 
comminute  the  alimentary  matters  upon  which 
the  animal  lives.  Moreover  the  thoracic  ex- 
tremities in  many  species  are  themselves  calcu- 
lated to  accomplish  one  or  all  of  these  offices 
with  various  degrees  of  success,  according  to 
their  form,  their  extent,  and  the  mode  in  which 


The  forms  and  dimensions  of 
these  organs  vary  considerably, 
and  are  obviously  in  harmony 
with  their  uses ;  they  are  by  so 
much  the  shorter  and  flatter  as 
they  are  more  peculiarly  appor- 
tioned to  the  oral  apparatus,  a 
disposition  which  is  nowhere 
more  conspicuously  displayed 
than  among  the  short-tailed  De- 
capods, in  which  they  resemble 
horny  laminse,  armed  with  teeth 
or  serrse  of  various  sizes,  and 
supporting  an  articulated  palp  (b, 
Jig.  4 08)  as  well  as  a  Jlabelliform 
or  whip -shaped  appendage  (c), 
which  penetrates  into  the  interior 
of  the  branchial  cavity.  The  last 
pair  of  all  (Jig.  410)  presents 

Fig.  410. 


Limulus  polyphemus,  (ventral  aspect.) 

a,  carapace;  b,  frontal  portion  of  the  carapace;  c,  thorax; 
d,  chelifera ;  e,f,g,h,i,.j,  legs,  the  basilar  portions  of  which 
surround  the  mouth  and  act  as  mandibles  ;  I,  under-lip ; 
m,  branchial  or  lamelliform  appendages ;  n,  mouth. 


itself  under  the 
shape  of  two  thin 
and  much  expand- 
ed laminae  which 
serve  as  a  kind  of 
broad  operculum  to 
cover  the  whole  of 
the  oral  apparatus. 

Stalling  from  this  complication  of  structure, 
the  greatest  in  the  series,  we  shall  see  the  ap- 
paratus degenerating  by  successive  degrees,  at 
the  same  time  that  in  any  given  group  its  com- 
position presents  much  less  of  constancy  or 
regularity.  The  Sergestes  among  the  Decapods 
have  one  pair  of  maxillary  feet  fewer  than  the 
highest  number;  the  Edriophthalmians  have 
no  more  than  a  single  pair,  whilst  in  the 
Thysanopoda  and  the  generality  of  the  Sto- 
mapoda  the  number  of  oral  appendages 


they  are  terminated.  The  most  favourable 
disposition  to  these  ends  is  observed  in  the 
lobsters,  crabs,  &c.;  in  a  word  in  a  very  great 
number  both  of  the  short  and  long-tailed  De- 
capods, in  which  the  anterior  thoracic  extre- 
mities terminate  in  pincers  of  greater  or  less 
strength,  armed  with  teeth  and  sharp  hooks 
which  give  them  increased  powers  of  pre- 
hension. This  form  results  mainly  from  the 
state  of  extreme  development  in  which  the  pe- 
nultimate articulation  frequently  occurs,  and 
its  assumption  of  the  shape  of  a  finger,  by  the 
prolongation  of  one  of  its  inferior  angles. 
Against  the  finger-like  process  thus  produced, 
which  is  of  great  strength  and  quite  immove- 
able,  the  last  articulation  can  be  brought  to 
bear  with  immense  force,  as  it  is  put  into  mo- 
tion by  a  muscular  mass  of  great  size,  and  in 
relation  with  the  extraordinary  size  of  the  pe- 


Fig.  412. 


CRUSTACEA. 

Fig.  413.        JYg.414.       .FYg.415. 


Fig.  412,    Ventral  aspect  of  the  cephalo  thoracic  portion  of  the 

Dichelestion. 
a,  trunk  or  sucker  ;  b,  maxillae. 

Fig.  413,    Th:  trunk  or  sucker  magnified, 
a.  the  labrum :  b,  the  mandibles. 


Fig.  414  if  415,   I  he  maxillae. 

nultimate  articulation  (the  claws,  pincers,  or 
chellfcrous  extremities). 

The  extremity  occasionally  terminates  in  two 
articulations  presenting  no  kind  of  unusual 
development,  but  the  last  of  which,  termi- 
nated by  a  sharp  point  and  armed  with  teeth 
or  serrae,  returns  upon  the  preceding  one,  so 
as  to  form  a  kind  of  hook  or  pincer,  opening 
in  the  opposite  direction,  (the  sub-cheliform 
extremities  of  the  Squilla  and  Crevettina). 
Lastly,  these  extremities  frequently  terminate 
in  a  simple  acute  angle  of  which  the  animal 
can  make  no  use  save  in  locomotion. 

In  the  Sucking  Crustacea,  which  live  parasi- 
tically  on  other  animals  and  feed  by  sucking 
their  blood,  the  structure  of  the  oral  apparatus 
is  extremely  different.*  Certain  pieces  which 
must  be  considered  as  analogous  to  the  labium 
and  languette,  are  elongated,  so  as  to  form  a 
trunk  or  cylindrical  tube,  of  variable  length, 
adapted  for  sucking,  and  in  the  interior  of 
which  are  lodged  the  mandibles,  now  pro- 
longed so  much  that  they  form  two  slender 
and  pointed  processes  the  extremities  of  which 
serve  as  a  lancet.  The  appendages  which  in 
the  masticating  Crustacea  constitute  the  jaws, 
here  continue  rudimentary,  and  the  three  pairs 
of  limbs  which  in  the  Decapoda  complete  the 
oral  apparatus,  under  the  name  of  maxillary 
extremities,  are  here  transformed  into  organs 
of  prehension,  of  different  forms,  by  means 
of  which  the  parasite  attaches  itself  to  its 
victim. 

In  the  whole  of  the  Crustacea  the  intestinal 
canal  presents  two  openings,  the  mouth  and 


*  See  our  "  Recherches  sur  1'Ofganization  de 
la  Bouche  des  Crustaces  Suceurs,"  Ann.  des  Sc. 
Nat.  t.  28 ;  Burmeister's  Beschreibung  einiger 
neuen  schmarotzer  Krebse,  in  the  Acta  Acad. 
Caes.  Leop.  Nat.  Cur.  vol.  xvii.  p.  1. 


773 

the  anus,  always  separate,! 
from  each  other  by  the  whole 
length  of  the  body. 

The  mouth  is  the  mere  an- 
terior and  outward  expansion 
of  the  oesophagus;  it  is  fur- 
nished with  nothing  that  can 
properly  be  compared  to  a 
tongue ;  the  horny  and  la- 
mellar organ  which  writers 
have  sometimes  spoken  of 
under  this  name  is  nothing 
more  than  the  lower  lip, 
which  has  already  been  de- 
scribed. 

The  oesophagus  itself  is 
short ;  it  rises  vertically  and 
runs  to  terminate  directly  in 
the  stomach.  Its  general 
structure,  as  well  as  that  of 
the  stomach  and  whole  of 
the  intestinal  canal,  bears  a 
very  close  resemblance  to 
what  we  observe  among  the 
superior  animals.  They  each 
consist  of  two  membranous 
layers  separated  by  one  of 
muscular  fibres,  always  of 
greatest  thickness  in  those  points  in  which  the 
most  energetic  contractions  take  place,  and 
especially  at  the  entrance  into  and  passage 
out  of  the  stomach. 

The  stomach  is  of  a  globular  form,  and  of 
very  great  capacity  ;  it  fills  a  considerable 
extent  of  the  cephalic  cavity,  and  presents  two 
portions  very  distinct  from  one  another;  the 
cardiac  region,  vertically  surmounting  the 
mouth  and  oesophagus,  the  axis  of  which  is 
lost  in  its  own ;  and  the  pyloric  region,  situ- 
ated behind  the  former,  and  forming  a  right 
angle  with  it. 

But  the  most  remarkable  feature  presented 
by  the  stomach  of  the  Crustaceans  is  the  very 
complex  masticatory  apparatus  it  contains. 
This  consists  of  a  considerable  number  of 
pieces,  the  form  and  disposition  of  which  vary, 
and  are  always  singularly  in  harmony  with  the 
kind  of  food  taken  and  the  general  habits  of 
these  animals.  The  apparatus,  as  well  from 
the  important  office  it  fulfils,  as  from  its 
being  no  where  else  encountered  in  so  perfect 
a  state  of  development,  were  worthy  of  a 
description  which  would  swell  this  article  to 
too  large  a  size;  we  shall  therefore  be  brief, 
and  merely  state  generally  that  it  consists  of  a 
great  number  of  pieces,  so  connected  as  to 
constitute  a  kind  of  solid  frame  armed  in- 
ternally with  tubercles  or  sharper  teeth  situated 
around  the  pylorus,  and  capable  of  being 
moved  so  as  to  bruise  or  tear  in  pieces  the 
alimentary  matters  subjected  to  their  action, 
and  as  they  are  about  to  pass  through  this 
opening.* 

The  different  pieces  composing  this  appa- 
ratus vary  considerably  in  the  different  genera, 


*  Vide  Cuvier,  Le9ons  d' Anatomic  Comparee, 
t.  iv.  p.  126,  and  Milne  Edwards,  Hist.  Nat.  des 
Crustaces,  t.  i.  p.  67,  for  further  details. 


774 


CRUSTACEA. 


Fig.  416. 


Fig.  417. 


Digestive  canal  of  the  Maja. 

a,  Cardiac  portion  of  the  stomach. 

b,  b,  Upper  portion  of   the  frame-work  of  the 

stomach. 

c,  Pyloric  portion  of  the  stomach. 

d,  The  small  intestine. 

e,  Termination  of  the  biliary  ducts. 

ft  Anterior  appendages  of  the  intestine. 
g,  Posterior  appendages. 
h,  Rectum. 

and  even  in  the  several  species  of  the  same 
genus.  Still  every  one  of  them  may  be  de- 
monstrated with  a  little  care,  in  the  whole  of 
the  Brachyura  and  of  the  Macroura.  They 
are  less  numerous,  and  are  singularly  modified 
in  proportion  as  we  recede  from  these  types. 
In  the  Squilla  mere  vestiges  only  of  the  ap- 
paratus are  found  in  two  semicorneous  pieces 
covered  with  rounded  projections ;  and  its 
functions  are  performed  by  a  branch  of  each 
mandible  which  penetrates  even  to  the  pyloric 
orifice  of  the  stomach. 

The  intestine  extends  from  the  pylorus  to 
the  anus  without  curve  or  convolution  in  its 
course  (fig.  4 1 6,  c?,  A).  In  the  superior  Crustacea 


Liver  of  the  Lobster. 

a,  stomach ;  b,  intestine ;  c,  left  lobe  of  the  liver 
in  its  natural  state  \  d,  right  lobe  dissected,  so 
as  to  show  its  structure  and  the  disposition  of  the 
biliary  ducts. 

it  may  be  distinguished  into  two  portions,  one  of 
which  may  be  named  the  duodenum,  the  other 
the  rectum.  These  two  portions  where  they 
occur  vary  extremely  both  in  their  nature  and 
in  their  relative  lengths.  Sometimes  they  are 
separated  by  a  valve  (Lobster)  corresponding 
internally  to  a  circular  external  elevation ;  but 
still  more  frequently  their  respective  limits  are 
not  obviously  marked,  and  among  the  whole 
of  the  inferior  members  of  the  family  the 
intestinal  canal  is  entirely  cylindrical,  and  per-, 
fectly  identical  in  its  constitution  through  its 
whole  length.  The  anus  is  constantly  seated 
in  the  last  ring,  and  is  closed  by  certain  mus- 
cular fibres  which  perform  the  office  of  a 
sphincter. 


CRUSTACEA. 


The  biliary  apparatus  of  the  Crustacea  is  of 
very  large  size  in  the  Decapoda.  The  liver  is 
symmetrical  (fig.  417),  and  consists  of  two 
halves  generally  separate  one  from  another, 
and  the  whole  organ  is  made  up  of  an  anglo- 
meration  of  coecums,  which  by  one  of  their 
extremities  empty  themselves  into  excretory 
ducts.  These  by  their  union  form  larger  and 
larger  trunks,  and  the  secreted  fluid  or  bile  is 
finally  poured  by  a  double  channel  into  the 
pyloric  portion  of  the  stomach.  The  liver  is 
found  to  undergo  extensive  modifications  as  it 
is  examined  in  individuals  lower  and  lower  in 
the  series;  in  the  Edriophthalmians,  finally, 
we  discover  nothing  except  three  pairs  of  bili- 
ary vessels  analogous  to  those  of  insects. 

The  liver  is  not  the  only  secerning  organ 
whose  product  is  poured  into  the  intestine. 
On  each  side  of  the  pyloric  portion  of  the 
stomach,  we  observe  two  blind  tubular  cavi- 
ties narrow  and  much  elongated  in  their  form, 
which  pour  out  a  whitish  fluid  (fig.  416,/,/J; 
and  at  the  point  of  conjunction  of  the  two  por- 
tions of  which  the  intestine  frequently  consists, 
as  has  been  said,  there  is  a  third  tubular  cavity 
or  vessel  in  all  respects  similar  to  these  two 
(fig.  416,  g).  These  tubuli  are  all  wanting  in 
the  Astacus  fluviatilis,  and  in  the  Astacus  ma- 
rinus  the  single  posterior  tubulus  is  the  only 
one  found.  Nothing  positive  is  known  with 
regard  to  the  uses  of  the  fluid  secreted  in  these 
tubuli. 

To  conclude,  there  are  two  organs  of  a  green 
colour  situated  on  either  side  of  the  oesopha- 
gus, the  structure  of  which  is  glandular,  and 
which  appear  to  bear  some  analogy  to  the  sali- 
vary glands* 

B.     Of  the  Hood  and  circulation. — We  are 


altogether  without  positive  information  as  to 
the  mode  in  which  the  nutritious  fluid,  elabo- 
rated by  the  process  of  digestion,  pusses  from 
the  intestinal  canal  into  the  torrent  of  the  cir- 
culation. Hitherto  no  chyliferous  vessels  have 
been  detected,  and  we  are  therefore  led  to 
believe  that  it  is  by  imbibition  that  the  trans- 
ference takes  place  from  the  intestine  to  the 
bloodvessels  in  the  Crustacea. 

The  blood  of  the  Crustacea  is  a  colourless, 
or  slightly  bluish  coloured  fluid,  holding  an 
abundance  of  circular-shaped  globules  in  sus- 
pension. It  is  extremely  coagulable.  Its  che- 
mical composition  has  not  been  investigated. 

This  nutritious  fluid  is  put  into  motion  by  a 
heart,  and  circulates  through  a  vascular  system 
of  great  complexness.  Willis,*  Swammer- 
dam,-f-  Cuvier,J  Desmarest,§  and  several  others 
have  given  a  description  of  this  system ;  but 
there  are  still  innumerable  points  upon  which 
opinions  remain  different.  The  following  are 
the  conclusions  to  which  M.  Audouin  and 
I  have  come  from  a  careful  study  as  well  of 
the  anatomical  disposition  of  the  circulatory 
apparatus  of  the  Crustacea,  as  of  the  progress 
of  the  blood  through  its  interior.|| 

The  circulation  of  the  blood  in  these  ani- 
mals is  accomplished  in  a  manner  very  similar 
to  what  takes  place  in  the  Mollusca.  The 
blood  pushed  forward  by  the  heart  is  distri- 
buted to  every  part  of  the  body,  from  whence 
it  is  returned  into  large  sinuses  situated  at  no 
great  distance  from  the  base  of  the  branchiae  ; 
from  these  sinuses  it  is  sent  on  to  the  respi- 
ratory apparatus  which  it  traverses,  and  from 
which  it  then  finds  its  way  to  the  heart,  to 
recommence  the  same  circle  anew.  The  heart 
is  consequently  aortic  and  single. 


Fig.  418. 


i 


Viscera  of  the  Cancer  Pagurus. 

f,  heart ;  a,  ophthalmic  artery  ;  o,  abdominal  artery ;  c,  stomach  ;  e,  skin ; 
g,  branchiae,  inverted  to  show  the  efferent  vessels  \  h,  vault  of  the  flancs  ; 
n,  branchiae  in  their  natural  position  ;  m,  flabellura ;  /,  liver  ;  k,  testicles. 


*  De  anima  brutorum,  caput  tertium,  p.  16. 

t  Collect,  academique,  partie  etrangere,  t.  v. 
p.  126. 

\  Le9ons  d'Anatomie  Comparee,  t.  iv.  p.  407,  et 
Regne  Animal,  Ire  ed.  t.  ii.  p.  512,  et  t.  iii.  p.  5. 


<S  Considerations  sur  les  Crustaces,  p.  57. 

j]  Recherches  anatomiques  et  physiologiques  sur 
la  Circulation  dans  les  Crustaces,  Ann.  des  Sc. 
Nat.  t.  11. 


776 


CRUSTACEA. 


The  heart  is  always  found  in  the  median 
line  of  the  body,  and  lying  over  the  alimen- 
tary canal  near  the  dorsal  aspect.  Its  form  is 
various ;  in  the  Decapods  it  is  nearly  square, 
and  lies  in  the  middle  and  superior  part  of  the 
thorax,  being  separated  from  the  carapace  by 
tegumentary  membranes  only,  and  may  be 
seen  in  the  space  included  between  the  two 
vaults  of  the  flancs.  In  structure  it  appears 
to  be  composed  by  the  interlacement  of  nu- 
merous muscular  fibres,  fixed  by  their  extremi- 
ties to  neighbouring  parts  and  passing  to  some 
distance  over  the  aggregate  at  either  end, 
so  that  the  whole  organ  brings  to  mind  such 
a  figure  as  would  be  formed  by  the  super- 
position of  a  number  of  stars  the  rays  of 
which  do  not  correspond.  In  the  other  orders 
this  general  form  of  the  heart  varies  conside- 
rably, from  the  figure  of  an  oblong  square  of 
rather  inconsiderable  size,  as  it  occurs  in  the 
Decapoda  (jig.  418,/J,  to  that  of  a  long  cylin- 
drical vessel  extending  through  the  whole 
length  of  the  body  as  it  appears  in  the  Stoma- 
poda  (fg.  419),  and  the  Edriophthalmians. 
In  the  former  of  these  it  gives  origin  to  six 
vascular  trunks,  three  of  which  issue  from  the 
anterior  edge,  and  three  from  the  posterior 
surface ;  each  of  the  six  openings  is  closed  by 
a  valvular  apparatus  which  prevents  the  regur- 
gitation  of  the  blood. 

The  first  of  the  three  anterior  vessels  is 
situated  in  the  median  line  and  is  distributed 
to  the  eyes,  in  consequence  of  which  we  have 
entitled  it  the  ophthalmic  artery  (a,  Jig.  418). 
Lodged  within  the  substance  of  the  general  te- 
gumentary membrane,  it  continues  its  course 
without  undergoing  any  subdivision  along  the 
median  line  through  the  whole  length  of  the 
thorax,  until,  arrived  opposite  the  eyes,  it  sub- 
divides and  terminates  in  two  branches  which 
penetrate  the  ocular  peduncles. 

On  the  two  sides  are  the  two  antennary 
arteries.  They  run  obliquely  towards  the  an- 
tennae, sending  off  numerous  branches  to  the 
tegumentary  membrane  in  which  they  are  at 
first  lodged;  they  then  plunge  more  deeply, 
sending  branches  to  the  stomach  and  its  mus- 
cles and  to  the  organs  of  generation,  between 
which  they  insinuate  themselves  by  following 
the  folds  of  the  same  membrane  which  parts 
them.  Lastly,  each  .of  these  vessels  subdivides 
into  two  branches,  one  of  which  proceeds  to  the 
internal  and  the  other  to  the  external  antenna. 

Two  hepatic  arteries  arise  from  the  fore  part 
of  the  inferior  surface  of  the  heart,  and  pene- 
trate the  liver,  there  to  be  ramified ;  but  they 
are  only  found  double  and  distinct  from  one 
another  so  long  as  the  liver  is  met  with  divided 
into  two  lobes,  as  it  is  in  the  River-crab  and 
Lobster. 

From  the  posterior  part  of  the  same  surface  of 
the  heart  there  proceeds  a  large  trunk,  which, 
from  its  importance,  might  be  compared  with 
the  aorta.  This  is  unquestionably  the  vessel 
which  many  authors  have  spoken  of  as  a  great 
vena  cava :  we  have  entitled  it  the  sternal  artery. 
It  bends  forwards,  giving  origin  to  two  abdo- 
minal arteries  (o,fig.  418),  dips  into  the  sternal 
canal,  distributing  branches  to  the  different 


thoracic  rings,  as  also  to  the  five  first  cephalic 
rings,  which  it  passes  over  in  its  course.  Meet- 
ing with  the  oesophagus  it  bifurcates,  but  still 
sends  branches  to  the  mandibles  and  the  whole 
of  the  anterior  and  inferior  parts  of  the  head. 

The  bulb  presented  by  the  sternal  artery  at 
its  origin,  in  the  Macroura,  is  the  part  which 
Willis  characterized  as  the  auricle  of  the  heart. 
As  concerns  the  two  abdominal  arteries,  which 
may  be  distinguished  into  superior  and  inferior, 
and  which  arise  from  the  kind  of  cross  which 
it  forms  almost  immediately  after  its  exit,  they 
are  in  precise  relationship  in  point  of  size  with 
the  magnitude  and  importance  of  the  abdo- 
men itself.  In  the  Brachyura  they  are  mere 
slender  twigs;  in  the  Macroura,  on  the  con- 
trary, they  are  capacious  stems,  and  the  inferior 
of  the  two  sends  branches  to  the  two  posterior 
pairs  of  thoracic  extremities. 

The  disposition  of  the  three  first  vessels  is 
the  same  in  the  Stomapoda  as  in  the  preceding 
species ;  but  the  great  vessel  which  represents 
the  heart  being  extended  through  the  whole 
length  of  the  body,  supplies  immediately  other 
arterial  branches  in  pairs,  and  in  number  equal 
to  those  of  the  rings. 

Fig.  419. 


u-4 


Arterial  system  of  the  Squilla. 
b,  heart ;  a,  anterior  artery. 

Fig,  420. 


Venous  system  of  the  Maja. 

a,  venous  sinuses ;    b,  branchiae ;    c,  vault  of  the 
flancs  partly  taken  away ;  d,  legs. 


CRUSTACEA. 


77  / 


The  blood  returns  from  the  different  parts  of 
the  body  by  canals,  or  rather  vacuities  among 
the  tissues,  (for  they  have  no  very  evident 
appropriate  parietes,)  which  terminate  in  the 
venous  sinuses,  situated  close  to  the  branchiae. 

In  the  short-tailed  Decapoda  we  lind  no 
more  than  a  double  series  of  these  sinuses, 
included  within  the  cells  of  the  rlancs  above 
the  articulations  of  the  extremities.  They  com- 
municate with  one  another,  and  they  appear  to 
have  no  parietes  other  than  lamiroe  of  cellular 
membrane  of  extreme  tenuity  which  cover  the 
neighbouring  parts.  Each  of  them,  neverthe- 
less, receives  several  venous  conduits,  and 
gives  origin  at  its  superior  and  external  part  to 
a  vessel  which,  traversing  the  walls  of  the 
flancs  at  the  base  of  the  branchiae,  conducts 
the  blood  to  the  latter  organs.  This  is  the 
external  or  afferent  vessel  of  the  branchiae. 

We  find  the  same  lateral  venous  sinuses  in 
the  Macroura;  but  instead  of  communicating 
with  one  another  athwart  the  thoracic  septa,  as 
is  the  case  in  the  Brachyura,  they  all  empty 
themselves  into  a  great  median  vessel,  which 
is  itself  a  venous  sinus,  and  occupies  the 
sternal  canal.  In  the  Squilla  this  sinus  is  al- 
most the  only  vessel  which  serves  as  a  reservoir 
to  the  venous  blood. 

The  blood,  after  having  been  arterialized  in 
its  passage  through  the  capillaries  of  the 
branchiae,  is  poured  into  the  efferent  vessel, 
which,  as  we  shall  immediately  have  occasion 
to  see  when  treating  of  the  respiratory  process, 
runs  along  the  internal  surface  of  each  bran- 
ch ia.  It  enters  the  thoracic  cells  in  the  same 
manner  as  the  afferent  vessel  passed  out  from 
them,  bends  upwardly  under  the  vault  of  the 
flancs,  and  thus  takes  its  course  towards  the 
heart.  It  is  to  this  portion  of  the  canal  that 
we  have  given  the  name  of  branchio-cardiac 
vessel. 

The  mode  in  which  the  blood  enters  the 
heart  is  still  a  subject  under  discussion.  Our  in- 
quiries lead  us  to  believe  that  this  fluid,  poured 
by  the  branchio-cardiac  canals  into  a  sinus 
situated  on  each  side  of  the  heart,  penetrates 
this  organ  by  means  of  certain  openings  situated 
in  those  parts  of  its  substance  which  are 
directly  opposite  to  the  canals  mentioned. 
But  Messrs.  Lund  and  Strauss  imagine  that 
the  blood  is  effused  as  it  were  into  the  peri- 
cardium (which  is  named  auricle  by  the  latter 
anatomist)  to  penetrate  from  thence  by  open- 
ings situated  on  the  superior  surface  of  the 
heart.*  These  openings,  however,  we  conceive 
to  be  closed  in  the  natural  state  by  means  of  a 
membrane,  and  it  is  also  worthy  of  remark 
that  the  writers  just  cited  were  unacquainted 
with  the  lateral  openings  which  establish  a 
much  more  direct  communication  with  the 
interior  of  the  organ.  We  must  also  add  that 
the  celebrated  John  Hunter,  whose  labours 
upon  this  subject  have  hitherto  remained  un- 
known to  the  world,  but  which  have  very  re- 
cently been  given  to  the  public  by  Mr.  Owen, 


comf 

" 


*  Lund,  Doutes  sur  1 'existence  du  svsteme  circu- 
latoire  dans  les  crustaces,  Isis  1825.    Strauss,  Anat. 
,p.  des  Animaux  articules. 
VOL.  I. 


had  long  ago  ascertained  the  existence  of  the 
venous  sinuses  and  of  the  lateral  openings  of 
the  heart,  although  he  seems  to  have  thought 
that  the  circulation  was  not  complete  in  the 
manner  we  have  described  i  • 

Jn  the  most  inferior  groups  of  the  class  of 
Crustaceans  the  apparatus  of  the  circulation 
becomes  much  less  perfect,  and  even  seems  to 
disappear  entirely  in  the  last  of  the  llaustel- 
late  tribes.  In  the  Argula,  for  instance,  there 
still  exists  a  heart,  but  the  arteries  as  well  as  the 
veins  appear  to  be  nothing  more  than  simple 
lacunae,  formed  in  the  interstices  between  the 
different  organs ;  and  in  the  Nicothoa,  &c.  no 
distinct  trace  of  any  portion  of  a  circulatory 
system  has  yet  been  discovered. 

C.  Of  the  respiration.— The  Crustacea,  like 
all  the  other  tribes  especially  formed  for  living 
under  water,  respire  by  means  of  certain  parts 
of  their  external  covering  modified  in  its  struc- 
ture in  order  to  fit  it  for  this  function,  and 
known  under  the  name  of  brahckite.  This 
character  is  even  so  completely  inherent  in  the 
organic  type  proper  to  this  class,  that  it  is  still 
preserved  in  certain  species  which  live  on  the 
land  and  not  in  the  water. 

Nothing,  however,  can  be  conceived  more 
various  than  the  form  and  disposition  of  the 
organs  of  the  branchial  respiration  among 
these  animals :  in  some  the  function  is  per- 
formed by  an  extremely  complex  apparatus, 
consisting"  in  great  part  of  organs  created  ex- 
pressly for  this  end ;  in  others  it  is  delegated 
to  certain  appendages  which  do  not  exist  for 
the  office  exclusively,  but  are  rather  turned 
from  their  more  ordinary  and  obvious  uses  to 
subserve  this  important  function.  In  others 
still,  we  neither  discover  special  organs  of 
respiration  nor  other  parts  whose  structure  fits 
them  evidently  to  supply  the  place  of  branchiae; 
in  these  cases  we  can  only  suppose  that  the 
oxygen  held  in  solution  by  the  water  acts  upon 
the  nutritious  fluid  of  the  animal  by  the  inter- 
medium of  the  entire  tegumentary  covering. 

Let  us  first  review  the  respiratory  apparatus 
in  its  state  of  greatest  complexity,  but  com- 
mencing with  it  in  the  embryo  and  following 
it  in  its  progressive  development,  in  order  that 
we  may  be  the  better  prepared  to  compare  it 
with  those  forms  which  will  be  presented  to  us 
among  species  less  elevated  in  the  series  of  the 
Crustaceans. 

In  the  earliest  periods  of  embryotic  life  of  the 
common  Astacus  fluviatilis,  we  discover  no  trace 
of  branchiae ;  but  at  a  somewhat  more  advanced 
stage  of  the  incubation,  though  still  before  the 
formation  of  the  heart,  these  organs  begin  to 
appear.  They  are  at  first  small  lamellar  appen- 
dices of  extreme  simplicity,  attached  above  the 
three  pairs  of  maxillary  extremities,  and  repre- 
senting the  flabelliform  portions  of  these  limbs. 
Soon  these  lamellar  appendages  elongate  and 
divide  into  two  halves,  one  internal,  lamel- 
lar and  triangular,  tlie  other  external,  small 
and  cylindrical;  lastly,  upon  the  surface  of 


*  Catalogue  of  the  Physiological  Serif:: 
parative  Anatomy,  contained  in  the  "•[ 
the  Royal  College  of  Surgeons,  vol.  r 

3  E 


•v  Com- 
iseum  of 


778 


CRUSTACEA. 


this,  striae  are  observed  to  appear,  which  are 
the  rudiments  of  the  branchial  filaments. 
During  this  interval  the  thoracic  extremities 
have  become  developed,  and  above  their  bases 
other  branchiae  have  made  their  appearance, 
presenting  in  the  beginning  the  form  of  tuber- 
cles, and  subsequently  that  of  stilets ;  smooth 
and  rounded  on  their  surface,  but  by-and-by 
becoming  covered  with  a  multitude  of  small 
tuberculations,  which  by  their  elongation  are 
gradually  converted  into  branchial  filaments 
similar  to  the  preceding.  During  this  period 
of  the  development  of  the  branchiae  these 
organs  are  applied  like  the  extremities  to  the 
inferior  surface  of  the  embryo ;  but  they  sub- 
sequently rise  against  the  lateral  parts  of  the 
thorax,  become  lodged  within  a  cavity  situated 
under  the  carapace,  and  thus  are  no  longer 
visible  externally. 

The  cavity  destined  to  protect  in  this  manner 
the  branchial  apparatus,  is  neither  more  nor 
less  than  an  internal  fold  of  the  common  tegu- 
mentary  membrane.  It  shows  itself  first  under 
the  guise  of  a  narrow  groove  or  furrow,  which 
runs  along  the  lateral  parts  of  the  thorax  below 
the  edge  of  the  lateral  piece  of  the  carapace. 
This  longitudinal  furrow  is  not  long  of  expand- 
ing, and  becomes  consolidated  by  its  superior 
edge  with  the  internal  surface  of  the  carapace, 
which,  by  being  prolonged  inferiorly,  consti- 
tutes the  external  wall  of  a  cavity,  the  opening 
of  which,  situated  above  the  base  of  the 
extremities,  becomes  more  and  more  contracted, 
and  ends  by  being  almost  entirely  closed.  The 
space  in  this  way  circumscribed  encloses  the 
branchiae,  and  constitutes  what  is  called  the 
respiratory  cavity  of  the  Decapod  Crustaceans. 

From  what  has  just  been  said,  it  would  ap- 
pear that  the  embryo  of  the  Astacus  fluviatilis 
presents  four  principal  periods  with  reference 
to  the  state  of  the  respiratory  apparatus;  Istly, 
that  which  precedes  the  appearance  of  this  ap- 
paratus; 2dly,  that  during  which  the  branchiae 
are  not  distinguishable  from  the  flabelliform  ap- 
pendages of  the  extremities,  or  in  which  it 
consists  of  simple  lamellar  or  stiliform  pro- 
cesses, which  appear  as  mere  processes  of 
other  organs  especially  dedicated  to  locomotion 
or  to  mastication ;  3dly,  that  characterized  by 
the  transformation  of  these  extremely  simple 
appendages  into  organs  of  a  complex  structure, 
entirely  distinct  from  the  extremities,  but  still 
entirely  external ;  4thly  and  lastly,  that  during 
which  the  branchiae  sink  inwards  and  become 
lodged  in  a  cavity  especially  adapted  for  their 
reception,  and  provided  with  a  particular 
apparatus  destined  to  renew  the  water  neces- 
sary to  the  maintenance  of  respiration. 

If  we  now  turn  to  the  examination  of  the 
apparatus  of  respiration  in  the  different  groups 
in  which  it  exhibits  important  modifications, 
we  shall,  in  the  series  of  Crustaceans,  encounter 
permanent  states  analogous  to  the  various 
phases  through  which  we  have  just  seen  the 
apparatus  passing  in  the  most  elevated  animals 
of  the  class. 

And,  in  fact,  the  first  period  which  we  have 
particularized  above  in  the  embryonic  life  of  the 
Decapod  is  exhibited  in  the  permanent  condi- 


tion of  some  inferior  Crustaceans,  in  which  not 
only  is  there  no  special  organs  for  respiration, 
but  in  which  none  of  the  appendices  occur 
with  such  modifications  of  structure  as  would 
fit  them  to  become  substitutes  for  the  branchiae, 
in  which,  consequently,  the  process  of  respira- 
tion, that  is  the  aeration  of  the  blood,  appears 
to  take  place  over  the  surface  of  the  body  at 
large.  The  greater  number  of  the  Haustellate 
Crustacea,  of  the  Entomostraca  properly  so 
called,  of  the  Copepoda,  and  even  of  the 
Phyllosomata,  appear  to  belong  to  this  type 
of  organization. 

A  state  analogous  to  that  which  characterizes 
the  second  period  in  the  development  of  the 
embryo  of  the  Decapod,  is  presented  to  us  in 
a  large  number  of  other  Crustaceans,  the  orga- 
nization of  which  is  more  perfect  than  that  of 
the  animals  of  which  mention  has  just  been 
made,  we  mean  the  Branchiopoda  and  Edri- 
ophthalmia,  in  which,  although  we  do  not  yet 
find  branchiae  properly  so  called,  that  is  to 
say,  organs  peculiarly  devoted  to  respiration, 
we  discover  certain  appendages  of  the  extre- 
mities which  serve  for  this  function.  In  the 
Branchiopoda  (fig.  421)  the  whole  of  the  tho- 
racic extremities  present 
a  lamellar  conformation, 
and  the  two  external 
portions  of  the  appen- 
dages corresponding  to 
the  palp  and  flabellum 
(fouet),  form  membra- 
nous vesicles  of  a  flat- 
tened form,  soft  to  the 
touch,  and  highly  vas- 
cular, the  structure  of 
which  appears  eminently  calculated  to  facilitate 
the  action  of  the  air  upon  the  nutritious  fluid. 


Fig.  421. 


In  the  Amphipoda  another  step  appears  to 
be  taken  in  the  elaboration  of  the  respiratoiy 
apparatus.  Not  only  does  the  function  of 
respiration  tend  to  become  centred  in  certain 
appendages,  whose  structure  is-  modified  for 
this  end,  but  this  localization,  if  the  term  may 
be  allowed,  becomes  more  complete  ;  for  the 
two  appendicular  portions  of  the  thoracic 
extremities  no  longer  concur  indistinctly  and 

Fig.  422. 


vicariously  in  the  performance  of  the  function ; 
the  palp  (b,fig.  422)  has  other  uses  apportioned 
to  it,  and  the  flabellum  (c)  alone  plays  the  part 
of  the  branchiae.  These  appendages,  in  other  re- 
spects, do  not  present  any  thing  peculiar  in  their 


CRUSTACEA. 


77«J 


conformation;  they  appear  like  a  vesicular  or 
foliaceous  expansion,  of  an  extremely  soft  tex- 
ture, which  is  attached  to  the  inner  edge  of 
the  base  of  the  thoracic  extremities;  their 
dimensions  generally  increase  from  before  back- 
wards, and  the  last  pair  of  thoracic  extremities 
is  not  furnished  with  any :  their  total  number 
varies  from  eight  to  twelve.  These  organs, 
suspended  under  the  thorax,  float  in  the 
ambient  fluid,  and  the  water  in  contact  with 
their  surface  is  incessantly  renovated  by  means 
of  the  motions  performed  by  the  abdominal 
extremities  of  the  animal,  motions  which  occa- 
sion a  rapid  current  from  behind  forwards 
along  the  ventral  aspect  of  the  body. 

In  the  Lcemodipoda,  the  parts  which  perform 
the  office  of  branchiae  are  vesicular  bodies 
formed  by  the  flabelliform  appendage  of  a 
certain  number  of  the  pairs  of  thoracic  extre- 
mities. In  the  Isopoda,  finally,  the  locomotory 
extremities  no  longer  serve  for  respiration,  the 
function  being  committed  to  the  five  first  pairs 
of  abdominal  extremities  which  are  entirely 
devoted  to  it  and  cease  to  have  any  other  uses. 
These  extremities,  which  are  designated  under 
the  name  of  false  branchial  limbs,  consist  of  a 
cylindrical  articulation,  supporting  two  folia- 
ceous, soft  membranous  laminae,  vascular  in  a 
greater  or  less  degree ;  frequently,  too,  we 
perceive  on  their  inner  side  a  small  appendage, 
which  may  be  regarded  as  analogous  to  the 
femur  or  stem  of  the  other  extremities,  whilst 
the  two  laminae,  of  which  mention  has  just 
been  made,  appear  to  represent  the  palp  and 
the  flabellum.  In  the  greater  number  of  Iso- 
poda these  organs  are  completely  exterior,  but 
in  several  (such  as  the  Idotea)  the  last  ring 

Fig.  423.  Fig.  424. 


Respiratory  apparatus  of  the  Idotea. 

of  the  abdomen  supplies  them  with  a  cavity, 
the  entrance  to  which  is  closed  by  valves 
which  constitute  the  two  appendages  of  the 
same  ring. 

The  Stomapoda  which  have  already  supplied 
us  with  an  instance  of  the  absence  of  deter- 
minate organs  of  respiration,  also  exhibit 
something  analogous  to  the  transition  state  of 
this  apparatus  during  the  second  period  of  the 
embryonic  life  of  the  Decapod.  In  the  genus 
Cynthia  the  branchiae  are  represented  by  a 
small  membranous  cylinder,  attached  by  its 
middle  to  a  peduncle,  itself  implanted  upon 
the  extremity  of  the  basilar  articulation  of  the 
five  first  pairs  of  abdominal  extremities. 

The  third  type  of  the  respiratory  apparatus 
specified  above,  is  presented  to  us  by  other 


Stomapods,  known  under  the  names  of  Squillae 
and  Thysanopodae.  In  those  creatures,  in  fact, 
we  discover  bnmcliku  properly  so  called,  the 
structure  of  which  is  greatly  complicated, 
more  so  even  than  in  the  ( 'rust;u 'I'lms  at  the 
very  head  of  the  series;  still  the  respiratory 
apparatus  as  a  whole  is  much  less  complete, 
for  they  are  not  included  in  a  cavity,  and  float 
freely  in  the  water  which  bathes  the  entire  sur- 
face of  the  body  of  the  animal.  In  the  Squills 
(lAg.425)  the  branchiae  are  attached  to  the  basilar 
joint  of  the  first  five  pairs  of  abdominal  extremi- 


Fig.  425. 


One   of    the 

of  the  Stj/iillfi.  a, 
bruin-bin  Jijred  to  the 
abdominal  extremity 


Ur 

ties,  and  each  consists  of  a  long  cylindrical 
tube,  upon  one  of  the  sides  of  which  proceeds 
a  series  of  small  tubes  disposed  parallel  to  one 
another  like  the  pipes  of  an  organ  and  support- 
ing in  their  turn  a  series  of  long  cylindrical  and 
very  numerous  tubes.*  In  the  Thysanopoda 
the  branchiae  also  resemble  plumes,  but  in- 
stead of  being  situated  on  the  abdomen,  they 
are  attached  to  the  thoracic  extremities.f 

Finally,  the  last  or  highest  term  of  develop- 
ment which  we  have  mentioned  in  the  River- 
crab,  is  also  presented  to  us  by  the  entire  order 
of  Decapod  Crustaceans.  Not  only  is  the  func- 
tion of  respiration  thrown  upon  particular 
organs,  created  expressly  for  this  purpose,  in 
the  whole  of  these  animals,  but  further,  the 
organs  themselves  are  lodged  and  protected 
within  especial  cavities,  and  the  renewal  of  the 
water  necessary  to  their  functions  is  secured  by 
the  action  of  distinct  appendages  belonging 
more  particularly  to  the  masticatory  and  loco- 
motory  apparatuses. 

Let  us  now  take  a  survey  of  the  branchial 
cavity.  It  occupies  (Jig-  426J  the  lateral  part 
of  the  thorax,  and  extends  between  the  vault  of 
the  flancs  and  the  lateral  portion  of  the  cara- 
pace, from  the  base  of  the  extremities  all  the 
way  towards  the  dorsal  aspect  of  the  animal. 
As  we  have  already  said,  it  is  formed  by  an  in- 
ternal fold  of  the  common  tegumentary  mem- 
brane, which,  after  having  formed  the  vault  of 
the  flancs,  re-descends  towards  the  base  of  the 
extremities  to  become  continuous  with  the 
carapace.  The  internal  and  inferior  wall  of 
this  cavity  is  consequently  formed  by  the  vault 
of  the  flancs  itself,  and  its  external  and  superior 
wall  by  a  membranous  septum,  which  in  the 
greater  part  of  its  extent  is  for  the  most  part 
connected  with  the  corresponding  portion  of 

*  Cuvier  Le9ons  d'Anat.  comp.  t.  iv. 

t  Mem.  sur  une  disposition   particuliere  de  1'ap- 
pareil  branchial  chez  quelques  crustaces,  par  Milne 
Edwards,  Ann.  des  Sciences  Nat.  torn.  xix. 
3  E   2 


780 


CRUSTACEA. 


Fig.  426. 


Fig.  428. 


Branchial  cavity  of 
the  Maja  Squinado 
laid  open. 


a,  branchiae  ;  6,  vault  of  the  flancs  ;   c,  carapace ; 
d,  efferent  duct;  e,  valve. 

the  carapace.  This  last  part  of  the  walls  of  the 
branchial  cavity  presents  an  epidermic  layer  of 
extreme  thinness,  but  covering  a  thick  and 
shaggy  membrane,  the  texture  of  which  is 
found  to  vary,  as  we  shall  see  by-and-by. 

The  cavity  thus  formed  communicates  ex- 
ternally by  two  passages,  the  one  destined  for 
the  entrance,  the  other  for  the  exit  of  the  water 
necessary  to  respiration.  The  disposition  of 
the  efferent  opening  varies  but  little;  that  of 
the  afferent  orifice,  on  the  contrary,  presents 
great  varieties  in  the  different  groups  of  which 
the  class  of  Decapods  is  composed. 

The  efferent  orifice  always  occupies  the  ante- 
rior extremity  of  the  branchial  cavity,  and  is 
continuous  with  a  canal  (rf,  jig.  426  and tf,Jtg. 
428)  the  parietes  of  which  are  formed  su- 
periorly by  the  epimeral  pieces  of  the  last  ce- 
phalic rings,  and  inferiorly  by  the  pterygo- 
stomian  portions  of  the  carapace  (bt  Jig.  427). 

Fig.  427. 


Head  of  the  Maja  Squinado. 

a,  afferent  opening  of  the  branchial  cavity ;  b, 
carapace ;  c,  anterior  extremities  ;  d,  posterior 
maxillipedes. 

This  canal  runs  forwards,  passes  to  the  out- 
side of  the  oral  apparatus,  and  terminates  in 
front  of  the  mouth  (g,fg-  428).  In  its  interior 
there  is  a  large  valve,  which  is  falling  and  rising 
continually,  as  if  it  moved  upon  a  pivot,  and 
which  in  this  way  occasions  a  rapid  current 


The  same  parts,  the  posterior  maxillipedes  and  a  por- 
tion of  the  carapace  having  been  removed. 

a,  afferent  opening ;  d,  portion  of  the  posterior 
maxillipedes ;  e,  commencement  of  the  efferent 
canal  (f)  g,  the  termination  of  the  efferent 
canal  j  h,  the  valve. 

from  behind  forwards  in  the  water  with  which 
the  cavity  is  filled.  This  valvular  apparatus  is 
neither  more  nor  less  than  the  flabelliform 
appendage  of  the  second  pair  of  maxillipedes 
which  acquire  dimensions  in  relation  with  the 
importance  of  the  new  function  they  have  here 
to  perform  (h,  Jig.  428). 

In  the  long-tailed  Decapoda,  and  in  the 
greater  number  of  Anomoura  of  the  same 
family,  the  respiratory  cavity  is  open  along 
the  whole  extent  of  its  inferior  edge;  the 
carapace  is  not  applied  accurately  to  the 
lower  margin  of  the  vault  of  the  flanc,  and 
it  is  by  the  empty  space  thus  left  above  the 
base  of  all  the  extremities  that  the  water  makes 
its  way  to  the  branchiae.  In  the  Brachyura 
the  afferent  orifice  of  the  branchial  cavity  is 
more  circumscribed,  but  varies  in  a  still  greater 
degree.  In  nearly  all  the  Crustacea  it  exists 
almost  immediately  in  front  of  the  base  of  the 
first  pair  of  ambulatory  extremities,  and  con- 
sists of  a  kind  of  cleft,  of  considerable  breadth, 
which  in  this  place  occurs  between  the  edge  of 
the  carapace  and  the  thorax  («,  Jig.  427),  and 
which  is  occupied  by  a  prolongation  of  the  ba- 
silar  joint  of  the  external  maxillary  limb  (rf), 
disposed  in  such  a  manner  as  to  close  it  com- 
pletely or  to  open  it  at  the  desire  of  the  ani- 
mal. In  the  genus  Dorippus  a  slight  variety 
in  the  disposition  of  this  opening  is  ob- 
served ;  here  at  first  view  it  appears  to  be 
pierced  directly  in  the  pterygostomian  portion 
of  the  carapace;  but  it  is  in  reality  formed 
by  an  empty  space  left  between  the  edge  of 
the  dorsal  shield  and  the  base  of  the  external 
maxillary  limb;  only  here,  this  space,  in- 
stead of  presenting  itself  immediately  in  front 
of  the  base  of  the  anterior  extremities,  is  se- 
parated from  this  by  a  prolongation  of  the 
carapace.  In  the  genus  Ranina  the  carapace 
is  joined  to  the  thorax  above  the  whole  of 
these  limbs,  so  as  to  leave  no  opening  in  this 
situation  for  the  passage  of  the  water,  and  it 
is  at  the  origin  of  the  abdomen  that  the  afferent 
opening  of  the  branchial  cavity  occurs.  Lastly, 
in  the  Leucosia,  this  cavity  is  in  like  manner 
completely  closed  above  the  base  of  the  extre- 
mities, and  it  is  by  a  conduit  parallel  to  the 
efferent  canal,  and  opening  outwardly  likewise 


781 


the  interior  of  the  branchial  cavity. 
Fig.  429. 


CRUSTACEA. 

in  front  of  the  mouth,  that  the  water  reaches     greatly,  especially  in  the  Macroura;    at  the 

most  it  is  twenty-two,  as  is  the  case  in  the 
astacus  and  the  most  nearly  allied  species; 
in  other  macroura  the  number  is  eighteen,  as  in 
the  Palinuri,  Scyllari,  Peneae;  fifteen,  as  in 
the  Gebiae ;  twelve,  as  in  the  Pandalus ;  ten,  as 
m  the  Calianassae;  eight,  as  in  the  Palemons; 
and  even  seven  only,  as  in  the  Crangons,  I  lip- 
pohti,  Sergestes,  &c.  In  the  Anomoura  the 
number  also  varies  very  much.  In  the  Bra- 
chyura  we  can  almost  always  reckon  nine 
branchiae  on  each  side  of  the  body;  two  of 
this  number,  however,  being  merely  rudiment- 
ary; sometimes  two  or  one  of  these  last  is 
entirely  wanting;  and  there  are  even  species 
in  which  the  branchia,  whicli  usually  occu- 
pies the  antipenultimate  ring  of  the  thorax, 
is  missing. 

The  mode  in  which  these  organs  are  placed 
varies  in  a  like  degree  :  in  the  Brachyura  (Jig. 
426)  the  whole,  with  the  exception  of  two  rudi- 
mentary branchiae,  are  arranged  along  one  and 
the  same  line,  and  rest  parallel  to  one  another 
upon  the  vault  of  the  flancs ;  the  two  last  rings 
of  the  thorax  never  support  any,  and  of  the  two 
rings  which  correspond  to  the  second  and  third 


Mouth  of  the  Leucosia. 
Fig.  430. 


The  same,  without  the  external  or  posterior  max- 
illipedes. 


The  branchiae  contained  in  the  two  cavities, 

one  on  either  side,  whose  conformation  we  have  pairs  of  extremities,  each  presents  a  single  py- 
>ow  described^  are  disposed  along  the  vaults  of  ramid  attached  to  a  hole  pierced  in  the 
the  flancs.  They  are  shaped  like  a  quad  ran-  epimeral  piece  near  to  its  inferior  edge  (/g.384). 

The  five  branchiae,  situated  in  front  of  these, 
are  attached  above  the  edge  of  the  vault  of 
the  flancs,  and  with  the  exception  of  the 
first  are  connected  two  and  two  upon  com- 


gular  pyramid,  the  base  being  fixed  by  means 
of  a  peduncle  to  the  inferior  part  of  this  vault 
or  to  the  membrane  which  extends  from  its  in- 
ferior edge  to  the  basilar  articulation  of  the 
corresponding  limb;  some  of  them  are  even 
inserted  into  this  articulation.  Each  of  these 
organs  consists  of  two  large  longitudinal  vessels 
situated  on  the  opposite 
edges  of  a  transverse 
septum,  which  extends 
from  the  base  to  the 
apex  of  the  branchia,  and 
presents  on  each  side 
a  great  number  of  lamel- 
lar or  cylindrical  pro- 
longations. Of  these 
two  principal  vessels 
the  external  is  the  affe- 
rent one,  of  which  men-  ' 
tion  has  already  been 
made  in  treating  of  the 

circulation  and  its  organs ;  the  internal  again  is 
the  efferent  vessel;  the  capillaries  by  which 
these  two  communicate  run  in  the  substance  of 
the  branchial  lamellae,  situated  on  either  side 
of  the  median  septum. 

In  the  whole  of  the  Decapoda  brachyura  and 
anomoura,and  in  the  greater  number  of  the  ma- 
croura, the  folds  of  the  tegumentary  membrane 
which  constitutes  each  branchia,  are  in  the 
form  of  very  thin  lamellae,  directed  perpendi- 
cularly to  the  axis  of  the  pyramid,  and  lying 
one  over  another  like  the  leaves  of  a  book. 
But  in  Crawfish,  the  Lobster,  the  Nethrops, 
the  Palinuri,  the  Scyllari,  and  the  Gebiae, 
these  lamellae  are  replaced  by  a  multitude  of 
small  cylinders,  attached  by  their  base,  and 
closely  packed  side  by  side,  like  the  bristles  of 
a  brush. 

The  number  of  branchial  pyramids  varies 


mon  peduncles.     Lastly,  the  two  rudimentary 
branchiae  which  complete  the  series  anteriorly, 


-FVg.431. 


are  arranged  under  the  base  of  the  preceding, 
and  attached  to  the  basilar  articulation  of  the 
second  and  third  pairs  of  maxillary  extremi- 
ties. In  the  Anomoura  and  the  Macroura, 
the  branchiae  are  often  found  arranged  in  several 
ranks,  and  generally  occur  on  the  two  last 
thoracic  segments,  as  well  as  upon  those  that 
precede  these  (Jig.  431). 

In  the  greater  number  of  the  Decapoda  the 
flabelliform  appendages  of  the  maxillary  or  of 
the  ambulatory  extremities  penetrate  into  the 
respiratory  cavity,  and  by  their  motions  sweep, 
as  it  were,  or  stroke  the  surface  of  the  branchiae. 
Some  anatomists  have  even  imagined  that  it  was 
by  their  action  that  the  water  necessary  to  respi- 
ration was  renewed  in  the  interior  of  the  branchial 
cavities;*  but  this  is  a  mistake;  these  appen- 


Cuvier,  Lc9ons,  t. 


432. 


782 


CRUSTACEA. 


dages  have  little  or  no  influence  upon  the  cur- 
rent which  is  continually  traversing  the  respi- 
ratory antrum,  and  which  is  produced  by  the 
motions  of  the  great  valvular  lamina,  already 
described  as  belonging  to  the  second  pair  of 
the  maxillipedes,  and  situated  in  the  efferent 
respiratory  canal. 

The  very  secondary  part  which  the  flabelli- 
form  appendages  of  the  thoracic  extremities 
play  in  the  interior  of  the  respiratory  cavities, 
is  of  itself  a  sure  indication  of  the  indetermi- 
nateness  of  their  numbers  and  relations  to 
the  branchial  pyramids.  Thus  whilst  in  the 
Lobster  and  the  nearly  allied  genera,  these  ap- 
pendages, to  the  number  of  five  on  either  side, 
belong  to  the  four  first  pairs  of  ambulatory  ex- 
tremities and  to  the  third  of  the  maxillary 
pairs,  and  run  from  below  upwards  between 
the  branchial  fasciculi,  we  only  find  three  pairs 
in  the  Brachyura,  belonging  exclusively  to  the 
maxillary  extremities,  and  penetrating  into  the 
branchial  cavities  horizontally,  two  on  the  outer 
surface  of  the  branchiae  and  one  between  the 
inner  surface  of  these  organs  and  the  flancs. 

We  said  in  beginning  this  article  that  the 
Crustacea,  by  their  general  conformation,  were 
evidently  adapted  to  a  purely  aquatic  life;  this 
proposition  must  only  be  understood  as  gene- 
rally applicable  to  the  class,  because  there  are 
genera  which  form  exceptions  to  it,  in  regard  to 
which  we  have  still  a  few  words  to  add. 

The  Telphusiae  and  some  other  families 
of  Crustaceans  have  the  power  of  emerging 
from  the  water,  and  of  entering  it  again 
after  a  longer  or  shorter  stay  upon  dry 
land.  But  this  fact  is  to  be  explained  by  the 
smallness  of  the  two  openings  by  which  each 
of  the  branchial  cavities  communicates  with 
the  exterior,  by  which  means  a  very  small 
amount  of  evaporation  only  takes  place  from 
them.  The  whole  of  the  Crab  tribe  have,  in  a 
greater  or  less  degree,  the  faculty  of  the  par- 
ticular species  mentioned,  provided  the  air  by 
which  they  are  surrounded  is  saturated  with 
moisture;  because  if  they  die  asphyxiated 
when  brought  into  the  air  under  ordinary  cir- 
cumstances, it  is  principally  because  their  bran- 
chiae having  become  dry  are  thereby  unfitted  to 
accomplish  their  functions. 

But  there  are  other  species  which  are  re- 
markable for  the  faculty  they  possess  not 
only  of  living  habitually  out  of  water,  but  be- 
cause they  are  infallibly  drowned  by  being 
kept  long  immersed  in  that  fluid— these  are 
the  Gecarcini  or  land-crabs.  Many  hypotheses 
were  broached  to  afford  an  explanation  of  this 
phenomenon,  when  a  careful  study  of  the  diffe- 
rent forms  under  which  the  organs  of  respira- 
tion present  themselves  in  these  different  genera, 
led  us  to  discover  in  the  membrane  which  lines 
the  walls  of  the  respiratory  cavities,  modifica- 
tions analogous  to  those  which  are  observed 
among  fishes  of  the  family  of  the  Acanthopterygia 
pharyngeae  labyrinthiformes,  &c.  Sometimes 
we  found  folds  and  lacunae  capable  of  servino- 
as  reservoirs  of  a  certain  quantity  of  water- 
sometimes,  as  in  the  Birgns,  a  spongy  mem- 
brane equally  well  calculated  to  store  up  the 
fluid  necessary  to  keep  the  organs  of  respira- 


tion  in  the  state  of  humidity  essentially  neces- 
sary to  enable  them  to  perform  their  functions. 
It  is  well  known,  too,  that  the  Land-crabs  of 
which  we  are  now  speaking,  never  remove  far 
from  damp  situations.  Some  naturalists  are  of 
opinion  that  the  tegumentary  membrane  with 
which  the  branchial  cavity  is  invested,  is  also 
the  seat  of  active  respiration;  M.  Geoffrey  St. 
Hilaire  even  goes  so  far  as  to  regard  the  growths 
with  which  the  surface  of  this  membrane  is 
covered  in  the  Birgus,  as  constituting  a  true 
lung. 

It  would  appear,  consequently,  that  it  is 
owing  to  the  activity  of  the  function  of  aerial 
respiration  in  the  Gecarcini,  that  these  ani- 
mals are  drowned  when  plunged  under  water, 
although  they  be  provided  with  branchiae ; 
and  it  is  owing  to  these  organs  being  kept  in 
a  suitable  state  of  humidity  that  these  creatures 
owe,  at  least  in  part,  their  faculty  of  breathing 
air. 

We  have  said  above  that  the  principal  cause 
of  the  death  of  our  ordinary  Crustaceans  exposed 
to  the  air  is  the  drying  up  of  their  branchiae ; 
but  this  is  not  the  sole  cause  of  the  asphyxia 
they  suffer ;  it  would  seem  that  the  collapse  of 
the  branchial  lamellae  which  takes  place  when 
these  organs  are  not  supported  by  the  water, 
and  the  greatly  diminished  extent  of  surface 
thereby  exposed  to  the  oxygenated  fluid,  con- 
tributes mainly  to  prevent  aerial  respiration 
from  proving  adequate  to  maintain  life  among 
the  common  aquatic  Crustacea. 

With  regard  to  the  modifications  presented 
by  the  respiratory  organs  of  the  Onisci,  which 
like  the  Gecarcini  live  far  from  water,  nothing 
certain  is  yet  known.  The  opinion  that  the 
abdominal  false  limbs,  which  serve  as  respi- 
ratory organs  among  the  Isopoda  in  general,  are 
here  vesicular,  and  perform  the  office  of  lungs 
internally,  whilst  their  external  surface  acts 
in  the  manner  of  gills,  still  requires  to  be 
confirmed. 

§  6.  Of  Generation. 

Sexual  organs  are  readily  demonstrated  in 
the  whole  class  of  Crustaceans,  but  those  of 
the  two  sexes  never  exist  in  the  same  indivi- 
dual. The  doubt  which  at  one  time  pre- 
vailed in  regard  to  this  fact,  and  which  mainly 
arose  from  no  other  than  females  of  certain 
species  having  ever  been  taken,  is  at  once 
put  an  end  to  by  the  circumstance  of  the  con- 
siderable dissimilarity  in  their  external  form, 
which  occurs  between  the  males  and  females 
of  these  species;  this  dissimilarity  indeed  is, 
in  some  instances,  so  great  that  naturalists 
were  led  into  the  error  of  regarding  the  male 
and  female  of  the  same  creature  not  only  as  be- 
longing to  different  species,  but  even  to  diffe- 
rent genera.  Oviparous  reproduction  is  also  a 
constant  character  of  the  class. 

Generally  speaking,  the  reproductive  appa- 
ratus, whether  in  the  male  or  in  the  female,  is 
perfectly  distinct,  especially  at  the  period  when 
the  organs  composing  it  are  in  a  state  of  acti- 
vity ;  and  one  of  the  most  remarkable  facts 
which  the  careful  study  of  this  part  of  the 
structure  of  the  class  has  afforded,  is  their  com- 


CRUSTACEA. 


plete  state  of  doubleness  ;  on  either  side  of  the 
body  we  find  an  organ  perfectly  distinct,  and 
often  wholly  independent  of  its  fellow  ;  to  such 
an  extent,  indeed,  is  this  carried,  that  among 
the  facts  with  which  modern  science  has  been 
enriched  in  regard  to  the  structure  of  the  Crus- 
tacea, one  by  no  means  the  least  interesting  is 
that  in  which  an  animal  of  this  class  was  actu- 
ally found  presenting  ID  either  half  of  its  body  a 
different  sex,  each  apparatus  complete  in  every 
one  of  its  conditions,  and  even  with  the  whole 
of  its  modifications.* 

Another  fact,  not  less  striking,  is  that  of  the 
analogy  which  exists,  at  least  among  the  more 
perfect  Crustaceans,  between  the  male  and  the 
female  reproductive  organ  This  similarity  is 
so  great  that  the  simple  inspection  of  the  organ 
is  riot  alone  sufficient  to  inform  us  always  of 
its  true  nature,  which  in  some  instances  can 
only  be  ascertained  by  the  most  carefnl 
examination. 

The  male  apparatus  consists  essentially  of  an 
organ  the  secreting  instrument  of  the  fecunda- 
ting fluid,  and  of  an  excretory  canal  variously 
modified.  These  two  parts  are  contained  within 
the  thorax  along  with  nearly  the  whole  mass  of 
other  viscera,  and  never  extend  lower  down 
than  the  last  ring  of  this  region  of  the  body. 
They  are  not  always  very  distinct  from  one 
another,  and  it  frequently  happens  that  the 
testis  and  the  excretory  canal  are  confounded 
inextricably  under  the  form  of  a  single  tube, 
nearly  identical  in  its  structure  from  beginning 
to  end.  The  length  of  this  canal  is  occasionally 
very  great  and  variously  convoluted  and  con- 
torted, so  that  its  relations  with  the  other  tho- 
racic viscera  become  excessively  multiplied. 
This  peculiarity  we  observe  very  well  in  the 
Maja  and  the  Cancer  pagurus  (see  Jig.  418). 
The  canal,  which  throughout  is  single,  is 
capillary  at  its  commencement,  but  increases 
gradually  in  its  dimensions  to  its  termina- 
tion. 

In  the  Astacus  fluviatilis,  on  the  contrary, 
the  two  portions  of  the  male  reproductive 
apparatus  are  perfectly  distinct,  and  severally 
completely  developed.  The  testis  (a,  Jig.  432) 
consists  of  capillary  secerning  vessels,  which 
are  readily  demonstrable,  and  presents  three 
lobes,  two  of  which  lie  forwards  upon  the 
sides  of  the  stomach,  and  one  backwards 
underneath  the  heart.  From  these  three  lobes 
two  excretory  canals  (&)  take  their  origin.  In 
the  Edriophthalmia  the  male  organ  is  com- 
posed of  two  or  three  elongated  vesicles,  which 
terminate  in  a  common  excretory  canal. 

It  is  in  the  Cancer  pagurus  perhaps  that  the 
male  organ  of  generation  is  most  highly  de- 
veloped. It  occupies  of  itself  a  large  por- 
tion of  the  thorax  (Jig.  418).  The  testis  pre- 
sents the  appearance  of  a  kind  of  grape 
cluster,  formed  of  four  principal  lobes,  which, 
studied  minutely,  are  found  to  be  made 
up  of  an  infinity  of  extremely  delicate  ver- 
micular canals,  contorted  so  as  to  form  great 
numbers  of  pellets.  This  first  portion  of 

*  An  account  of  an  Hmuaplirodite  Lobster, 
by  Dr.  Nichols,  Philos.  Trans.  1730,  p.  290. 


I 


Male  organs  of  the  Astacus  Fluviatilis. 
a,  testis;    b,  excretory  ducts  ;    c,  terminal  portion 
of  these  ducts;  d,  orifice;  e,  last  pair  of  ambu- 
latory logs. 

the  organ  is  situated  in  front  of  the  thorax, 
and  terminates  in  a  primary  large  convoluted 
vessel  lying  on  the  side  of  the  stomach ;  be- 
hind and  in  connexion  with  this  we  perceive 
the  vas  deferens,  properly  so  called;  it  is  a 
canal  of  considerable  size,  much  convoluted, 
and  of  a  milky  white  colour;  it  traverses  the 
thorax,  still  twisting  about,  penetrates  the  cell 
of  the  last  pair  of  ambulatory  extremities,  and 
opens  outwardly  on  their  basilar  piece.  This 
indeed  is  the  situation  in  which  the  copulatory 
organs  of  the  Crustacea  generally  appear. 
Still,  in  many  Brachyura  of  the  Catometopa 
family,  the  Ocypoda  and  Grapsus,  for  ex- 
ample, the  external  opening  of  the  male  gene- 
rative organ  is  found  on  the  sternal  part  of  the 
last  thoracic  ring ;  and  there  are  even  several 
of  these  animals  in  which  the  efferent  canal, 
after  having  attained  the  external  surface  in  the 
basilar  articulation  of  the  last  pair  of  ambu- 
latory extremities,  returns  inwards,  and  pene- 
trates by  a  small  groove,  which  conceals  it 
until  it  has  attained  to  that  portion  of  the 
sternum  which  is  hidden  by  the  abdomen ; 
an  example  of  this  occurs  in  the  Gonoplax ; 
In  the  ordinary  state  the  excretory  canal  termi- 
nates on  the  edges  of  the  opening,  but  at  the 
instant  of  sexual  intercourse  the  extremity  of 
the  canal  undergoes  a  kind  of  erection,  and 
by  becoming  folded  upon  itself  like  the  finger 
of  a  glove,  projects  externally,  so  as  to  form  a 
kind  of  penis  adequate  to  the  intromission  of 
the  fecundating  fluid.  This  later  circumstance 
was  long  unknown  to  naturalists,  who  were 


784 


CRUSTACEA. 


accustomed  to  look  upon  the  members  of  the 
first  and  second  abdominal  rings  as  the  ex- 
ternal male  instruments.  These  two  pairs  of 
extremities,  in  fact,  (Jig.  433),  are  distinguished 


Fig.  433. 


Members  of  the  first  and 
second  abdominal  rings  of 
the  Male  Ma$a. 


from  the  rest  by  their  shape,  which  is  styli- 
form,  and  their  structure,  which  is  tubular, 
being  composed  of  two  horny  laminae  convo- 
luted one  upon  another,  the  first  including 
the  second.  But  direct  observation  has  de- 
prived them  of  all  claim  to  be  considered  as 
fulfilling  any  office  of  so  much  consequence  in 
the  economy  of  the  Crustacea  as  that  of  con- 
veying the  fecundating  fluid  from  the  body  of 
male  into  that  of  the  female.  At  the  most, 
they  can  only  be  regarded  as  organs  of  excita- 
tion, and  which  the  animal  may  perhaps  em- 
ploy at  the  same  time  to  guide  the  male  into 
the  female  organ. 

The  female  reproductive  apparatus  of  the 
Crustacea,  in  its  highest  state  of  complication, 
«onsists  of  an  ovary,  an  oviduct,  and  copulatory 
pouches. 

Fig.  434. 


Female  organs  of  the  Maja  Squinado. 

The  ovaries  in  the  Decapoda  brachyura  resem- 
ble four  cylindrical  tubes  (a,  b,jig.  434)  placed 
longitudinally  in  the  thorax,  and  divided  into 
two  symmetrical  pairs,  each  opening  into  a 
distinct  oviduct,  yet  communicating  with  one 
another  by  a  transverse  canal  («'),  and  by 
the  intimate  union  of  the  two  posterior  tubes 
in  a  portion  of  their  length  (6').  The  ovi- 
ducts, as  well  as  the  ovaries,  are  of  a  whitish 
colour;  they  are  short,  and  become  united 


in  their  course  to  a  kind  of  sac  (c),  the  neck 
of  which  extends  to  the  exterior  of-  the  ani- 
mal's body  (d);  there  is  one  of  these  on 
each  side,  and  they  are  known  by  the  name  of 
the  copulatory  pouches.  It  is  into  these  reser- 
voirs that  the  male  pours  the  fecundating  fluid, 
which  is  here  stored  up  and  applied  to  the 
ova  as  they  pass  in  succession  along  and  out 
of  the  oviducts.  These,  after  a  course  which 
is  never  long,  terminate  at  the  vulvse,  openings 
formed  in  the  sternal  pieces  of  the  segment 
which  supports  the  third  pair  of  ambulatory 
extremities. 

The  Anomoura  and  Macroura  have  no  copu- 
latory pouches,  and  their  vulvae  are  situated 
on  the  basilar  joint  of  the  ambulatory  ex- 
tremities of  the  third  pair.  The  mode  in 
which  fecundation  is  accomplished  in  these 
genera  is  consequently  much  less  apparent 
than  in  the  Brachyura.  Many  writers  are 
of  opinion  that  this  operation  takes  place  in 
the  interior  of  the  ovaries,  a  process  that 
appears  by  no  means  feasible  on  account 
of  the  inequality  of  development  of  the  ova, 
which  is  such,  that  the  last  of  them  are  not  in 
being  even  long  after  the  first  have  been  ex- 
pelled. It  would  perhaps  be  more  correct  to 
suppose  that  fecundation  does  not  take  place 
till  after  the  ova  are  laid,  which  we  know  to  be 
the  case  among  the  Batrachia  and  the  greater 
number  of  fishes. 

The  female  Crustacean  does  not  abandon  her 
eggs  after  their  extrusion.     Those  of  the  Deca- 
pods preserve  them  under  their  abdomen   by 
means  of  the  abdominal  extremities  modified 
Fig.  435.      in  their  structure  (Jig.  390  and 
435);      the    Edriophthalmia, 
again,  keep  them  under  their 
thorax  by   means  of  the  fla- 
belliform   appendages   of  the 
extremities   belonging   to  this 
region    (Jig.  436);  whilst  the 
inferior  genera,    such  as    the 
Entomostraca,    &c.  have  sus- 
pended to  the  external  orifices 
either     horny     tubes     or     a 


Ventral  aspect  of  the  female 
Cymothoa. 

p,  legs ;  f,  flabelliform  ap- 
pendages which  unite  so 
as  to  form  a  cavity  des- 
tined to  contain  the  ova. 


CRUSTACEA. 


785 


pair  of  membranous  sacs  which  contain  and 
transport  them  from  place  to  place.  These 
varieties  in  the  accessory  organs  of  gene- 
ration, are  in  many  cases  sufficient  to  distin- 
guish the  sexes :  thus,  among  the  Decapoda 
brachyura,  the  females  are  known  at  a  glance 
by  their  wider  abdomen,  which  is  sometimes 
of  such  dimensions  as  to  cover  almost  the 
whole  sternum.  Sometimes  these  sexual  diffe- 
renceti  extend  to  the  antennae  and  to  various 
other  organs;  sometimes  it  even  influences  the 
size,  and  occasionally,  as  we  have  said,  the 
general  external  conformation  is  modified  to 
such  a  degree,  that  the  male  and  the  female 
of  oire  and  the  same  species  have  been  taken 
as  types  of  two  distinct  genera.  There  are 
some  species  jsf  which  the  females  only  are  as 
yet  known  to  naturalists. 

The  ovum  appears  to  be  formed  in  the  walls 
of  the  ovary,  from  whence  it  is  detached  when 
it  has  attained  a  certain  size,  and  falls  into  the 
cavity  of  the  organ.  We  have  already  stated 
in  what  manner  it  is  expelled,  and  in  what 
mode  fecundation  is  accomplished  in  its  pas- 
sage through  the  oviducts,  or  after  its  extru- 
sion. The  distinguished  German  naturalist, 
Rathke,  has  given  particular  attention  to  the 
divers  phases  of  the  evolution  of  the  egg  of 
the  Astacus  fluviatilis,  as  well  before  as  after  its 
escape  from  the  ovary  and  oviduct;  and  we 
believe  we  cannot  conclude  this  article  more 
satisfactorily  than  by  presenting  our  readers 
with  a  simple  and  brief  analysis  of  his  work.* 

The  first  and  earliest  form  under  which  the 
ovum  meets  the  eye  in  the  ovary  is  that  of  a 
transparent  vesicle,  its  walls  of  extreme  te- 
nuity, and  filled  with  a  watery  fluid.  This  is 
the  vesicle  of  Purkinje.  By-and-by  there  is 
another  membranous  and  very  thin  envelope 
formed  all  round  this  vesicle,  and  in  the  minute 
interval  that  separates  the  two  coverings  there 
is  a  second  fluid  deposited,  transparent  like 
the  other  at  first,  but  soon  becoming  opaque, 
whitish,  and  viscid;  this  is  the  vitellus  or 
yolk.  As  this  increases  in  size,  the  vesicle  of 
Purkinje,  which  still  preserves  its  first  dimen- 
sions, quits  the  centre,  and  goes  to  be  attached 
to  the  circumference,  which,  at  last,  it  almost 
touches  at  one  point.  During  this  time  the 
vitellus  or  yolk  is  continually  declining  in 
transparency,  on  account  of  the  formation 
of  an  infinity  of  globules,  which,  at  length, 
transform  it  into  a  viscid  mass  of  a  deep  brown 
colour. 

During  the  last  stage  of  its  continuance  in 
tfte  ovary  the  vesicle  of  Purkinje  disappears, 
and  the  first  rudiments  of  the  germ  are  disco- 
vered. This  series  of  changes  might  induce 
the  belief  that  the  germ  is  neither  more  nor 
less  than  the  liquid  of  the  vesicle  shed  upon 
the  surface  of  the  vitellus.  Its  form  at  first 
resembles  that  of  a  slight  whitish  cloud,  which, 
by  slow  degrees,  changes  into  an  opaque  white 
spot,  well  defined,  and  covering  nearly  the 
sixth  part  of  the  entire  surface. 

The  egg  is  in  the  above  state  at  the  time  it 

*  Untersuchungen  ueber  die  Bildung  und  Ent- 
wickelung  des  Flusskrebses,  fol.  Leipz.  1829. 


is  received  into  the  oviducts.  These  canals 
secrete  an  albuminous  fluid,  which  surrounds 
the  vitellus  and  its  envelope,  and  which  itself 
becomes  covered  with  a  membranous  involu- 
crum,  called  the  'chorion  or  dermoid  envelope 
of  the  ovum.  Another  membrane  still  is 
thrown  around  the  last,  to  serve  as  the  means 
of  attaching  the  ovum  to  the  false  abdominal 
extremities  of  the  mother. 

When  the  process  of  incubation  begins, 
the  surface  of  the  yolk  is  first  seen  to  be- 
come covered  with  star-like  or  serrated  spots, 
whitish  in  the  first  instance,  and  then  white, 
which  by-and-bye  disappear  entirely.  The 
germ  at  the  same  time  is  extended  uniformly 
over  the  whole  surface  of  the  yolk ;  but  again 
it  seems  to  collect  towards  a  point  under  the 
form  of  a  white  spot,  which  is  the  blastoderma. 
This  spot,  after  undergoing  certain  variations 
in  its  form  and  dimensions,  ends  by  becom- 
ing elliptical  with  a  slight  furrow  in  its  mid- 
dle, shaped  like  a  horse-shoe.  This  furrow 
soon  extends ;  its  extremities  meet,  and  its 
centre  becomes  depressed,  so  as  to  assume 
the  appearance  of  a  sacculus  of  some  depth. 
The  blastoderma  enlarges  at  the  same  time, 
and  presents  the  appearance  of  a  cordiform 
spot.  It  is  at  the  bottom  of  the  sacculus  but 
just  mentioned,  and  in  the  nearest  point  of 
the  blastoderma,  that  the  first  rudiments  of 
organs  make  their  appearance. 

It  is  now  that  the  orifice  of  the  sacculus 
begins  to  enlarge ;  the  edges  separate ;  its 
bottom  rises,  so  as  at  length  to  become  pro- 
minent, and  a  small  nipple-like  elevation  ap- 
pears upon  it,  hidden  in  some  measure  by  the 
edge  of  the  sac,  which  turns  out  to  be  the 
rudiments  of  the  posterior  portion  of  the  body. 
At  the  same  epoch  there  are  formed  anteriorly, 
on  either  side  of  the  median  line,  two  pairs  of 
small  strap-like  bodies,  which  are  by-and-bye 
discovered  to  have  been  the  rudiments  of  the 
antennae,  and  another  pair,  which  are  the  ear- 
liest vestiges  of  mandibles.  Between  the  two 
anterior  antennae  an  azygous  point  presents 
itself,  which  is  the  rudiment  of  the  labrum, 
and  which,  by  the  progressive  development  of 
the  neighbouring  parts,  shifts  by  slow  degrees 
to  its  final  position  between  the  second  pair  of 
antennae. 

By  slow  degrees  the  blastoderma,  the  pe- 
ripheral portion  of  which  is  much  thinner  and 
more  transparent  than  the  middle  portion,  is 
seen  to  extend  on  the  surface  of  the  vitellus, 
and  at  length  to  envelope  it  completely.  Du- 
ring this  time  the  three  pairs  of  spots  which 
represent  the  antennae  and  the  mandibles  are 
growing  larger,  their  edges  becoming  distinctly 
defined,  and  their  extremities  are  receding 
from  the  surface  of  the  blastoderma,  under 
the  form  of  a  little  cylinder,  the  end  of  which 
before  long  divides  into  two.  After  the  an- 
tennae have  been  seen,  the  peduncles  of  the  eyes 
make  their  appearance,  and  detach  themselves 
by  degrees  from  the  blastoderma,  as  the  pre- 
ceding appendages  had  done.  The  nipple-like 
projection  which  we  have  seen  formed  at  the 
bottom  of  the  small  blastoderrnic  sac  enlarges 
at  the  same  time,  and  assumes  the  form  of  an 


786 


CRUSTACEA. 


elongated  lamina,  the  free  end  of  which  is 
turned  forwards,  and  before  long  advances 
nearly  to  the  labrum. 

In  the  space  included  between  the  mandibles 
and  the  fold  formed  by  the  abdominal  lamina 
of  the  embryo,  of  which  we  have  just  spoken, 
we  now  perceive  the  rudiments  of  two  pairs  of 
jaws  and  of  the  first  pair  of  maxillary  extremi- 
ties, then  of  the  second  pair  of  these  latter  or- 
gans, and  soon   afterwards   of  the  third  pair. 
These  appendages  appear   in  the  same  man- 
ner as  the  antennae,  and  in  proportion  as  they 
are  evolved,  the  fold  that  marks  the  origin  of 
the  caudal  lamina  of  the  embryo  recedes  from 
the  anterior  part  of  the  body;  by  little  and  little 
the  basilar    portion    of    the  lamina  becomes 
straightened,  so  as  to  gain  the  same  plane  as 
the  remainder  of  the  blastoderma,  whilst  its 
terminal   portion    continues    bent   underneath 
against  the  former.     The  five  pairs  of  ambula- 
tory extremities  make  their  appearance  succes- 
sively  in    the    same  manner  as  the  antennae 
and  the  oral  appendages;   the  same  may  be 
said   with    regard  to  the  abdominal  extremi- 
ties ;  and  whilst  this  formation  is  going  on,  the 
annular  divisions  of  the  abdominal  portion  of 
the  body   are  observed  to  be  evolved.     The 
carapace  at  length  begins    to  be    formed  in 
the  manner    already   indicated,  and    the   ex- 
tremities,   as  they   sprout,  alter  their  shapes, 
and     become    more    and    more  unlike    one 
another,  as   they  approach  the  term   of  their 
embryotic  development. 

The  alimentary  canal  begins  to  be  formed 
by  its  two  opposite  extremities.  The  earliest 
traces  of  the  oral  aperture  are  perceived  nearly 
at  the  same  time  as  the  labrum,  under  the  form 
of  a  small  cavity,  which  becomes  continually 
deeper  and  deeper.  Some  short  time  after- 
wards, and  before  the  appearance  of  the  jaws, 
we  distinguish  towards  the  summit  of  the  ab- 
dominal tubercle,  a  slight  depression  which 
grows  rapidly  deeper  in  order  to  form  the  anus. 
About  the  same  period  a  very  delicate  and 
gelatinous-looking  membrane  begins  to  be 
formed  between  the  inner  aspect  of  the  middle 
portion  of  the  blastoderma  and  the  vitellus ; 
this  increases  rapidly,  and  sends  prolongations 
towards  the  mouth  and  anus,  which  soon  be- 
come hollowed  out  into  a  cavity,  and  are  fi- 
nally converted  into  two  small  perpendicular 
canals.  The  one  of  these  canals  terminating 
at  the  mouth  is  the  commencement  of  the 
oesophagus  and  stomach  ;  the  other,with  which 
the  anus  is  soon  found  to  be  in  connexion,  is 
the  rudiment  of  the  intestine.  The  rest  of  the 
membrane  in  question  is  observed  to  extend 
rapidly  and  at  length  completely  to  envelope 
the  vitellus.  At  this  epoch  of  the  develop- 
ment of  the  embryo,  the  sac  thus  formed 
covers  the  blastoderma,  incloses  the  yolk,  and 
towards  its  lower  part  presents  two  funnel-like 
portions  by  which  it  is  made  to  communicate 
with  the  gastric  and  intestinal  portions  of  the 
digestive  canal,  the  formation  of  which  we 
have  just  had  occasion  to  speak  of.  These 
two  portions  of  the  digestive  canal  as  they 
increase  in  size  approach  one  another;  the 
rest  of  the  sac  folds  inwards  upon  itself,  and 


diminishes  more  and  more  in  size  until  it 
disappears  entirely,  arid  the  stomach  and  in- 
testine form  one  perfectly  continuous  tube. 
At  the  point  where  the  intestine  is  connected 
with  the  sac  inclosing  the  yolk,  two  small 
thickenings  are  seen,  which  by-and-by  acquire 
the  form  of  appendages  and  become  covered 
with  little  warty-looking  enlargements;  this  is 
the  liver  beginning  to  be  formed.  The  enlarge- 
ments of  which  we  have  spoken  constitute  its 
lobuli,  and  these  slowly  divide  into  a  mul- 
titude of  long  slender  vessels. 

The  heart  begins  to  be  developed  about  the 
same  time  as  the  intestinal  canal.  It  makes 
its  appearance  towards  the  dorsal  part  of  the 
body,  a  short  way  above  the  commencement 
of  the  abdomen,  and  shows  itself  at  first  under 
the  guise  of  a  small  pyriform  cavity  hollowed 
out  of  a  membrane  supplied  by  an  inner  la- 
mina of  the  blastoderma.  The  arteries  begin 
to  show  themselves  towards  the  same  period 
in  the  substance  of  this  same  blastodermic 
lamina,  and  in  the  beginning  present  neither 
ramifications  nor  any  communication  with  the 
heart. 

We  have  already  spoken  of  the  develop- 
ment of  the  apparatus  of  respiration  and  of 
that  of  the  nervous  system  at  such  length  as 
to  render  it  unnecessary  to  enter  farther 
upon  these  parts  of  the  subject  here. 

The  greater  number  of  the  Crustacea  do  not 
escape  from  the  membranes  of  the  egg  until  they 
have  attained  such  a  perfect  state  of  develop- 
ment, that  they  possess  the  whole  of  the  organs 
they  will  ever  exhibit,  and  have  attained  a  form 
which  differs  but  little  from  that  which  is  to 
distinguish  them  when  arrived  at  maturity  or 
become  adult.  The  case,  however,  is  different 
as  regards  some  of  these  animals;  these  are 
born  in  some  sort  prematurely,  and  only  attain 
their  distinctive  formation  after  their  exit  from 
the  egg.  The  changes  which  they  undergo 
between  the  term  of  their  birth  and  that  of 
their  perfect  growth  are  sometimes  so  great  that 
they  are  every  way  deserving  of  the  name  of 
metamorphoses. 

These  changes,  whatever  their  amount,  may 
depend  on  the  following  circumstances : — 1.  the 
continuation  of  the  normal  work  of  development, 
which  has  not  been  completed  in  the  ovum  ; 
2.  the  unequal  growth  of  different  parts  of  the 
body;  and,  3.  the  atrophy  and  complete  ulti- 
mate disappearance  of  certain  parts. 

It  is  among  the  lower  Crustaceans  that  this 
kind  of  premature  birth  takes  place  most  fre- 
quently :  thus  the  sugient  Crustaceans  and  the 
Entomostraca  quit  the  membranes  of  the  ovum 
at  a  stage  of  development  which  corresponds 
with  one  of  the  earlier  of  those  under  which 
the  Decapoda  present  themselves  to  our  notice ; 
they  are  all  of  an  oval  figure,  and  only  appear 
provided  with  a  very  limited  number  of  styli- 
form  extremities.  The  common  Cyclops,  for 
instance,  does  not  show  the  posterior  part  of 
the  body  at  the  time  of  its  exclusion  from  the 
ovum,  although  this  subsequently  forms  an 
elongated  tail ;  it  is  nearly  spherical  at  first,  and 
is  provided  with  no  more  than  two  antennae 
and  four  extremely  short  feet.  It  continues 


CYST. 


787 


in  this  state  till  the  fourteenth  day,  when  a 
small  projection  makes  its  appearance  from  the 
hinder  part  of  the  body  ;  on  the  twenty-second 
day  it  acquires  a  third  pair  of  extremities,  and 
on  the  twenty-eighth  day  it  changes  the  tegu- 
mentary  covering  of  its  body.*  Several  Edrioph- 
thalmians  are  also  born  before  they  have  ac- 
quired the  whole  of  their  extremities  ;  but  we 
know  of  no  instance  of  the  appearance  of  one 
or  more  pairs  of  extremities  after  exclusion 
from  the  ovum  among  the  superior  Crustaceans. 

The  changes  of  form  which  take  place  in 
parts  already  existing,  and  which  depend  on 
the  unequal  rates  of  increase  with  which  the 
different  parts  of  the  animal  approach  their 
final  state  of  development,  are  often  very  con- 
siderable, and  commonly  tend  to  occasion 
peculiarities  of  conformation  in  the  adult, 
which  distinguish  it  from  allied  species,  and 
imprint  upon  it  the  character  proper  to  the 
tribe,  genus,  species,  and  even  sex  to  which 
it  belongs.  These  implicate  one  part  in  one, 
another  in  another ;  here  it  is  the  thorax 
which  grows  more  rapidly  than  the  abdomen 
and  greatly  preponderates;  there  it  is  the 
abdomen  which,  smaller  at  first  than  the 
thorax,  increases  in  dimensions,  and  finally 
exceeds  it  in  size :  in  other  instances,  again, 
the  phenomenon  of  extraordinary  growth  is 
displayed  in  certain  extremities,  or  even  in 
certain  articulations  of  these  extremities,  which 
follow  differences  in  the  proportions  of  the 
body  and  in  the  forms  of  its  different  parts. 
These  differences  contribute  in  general  to  in- 
crease the  dissimilarity  which  already  exists 
between  the  different  segments  of  the  body,  and 
may  therefore  be  regarded  as  a  sequence  in  the 
general  tendency  of  these  animals  to  become 
more  complicated  in  their  structure  in  propor- 
tion as  they  rise  in  the  series  to  which  they 
belong,  or  in  the  course  they  have  to  run  in 
order  to  attain  their  perfect  state. 

To  conclude :  the  modifications  depending 
on  the  atrophy  and  the  disappearance  of  certain 
parts  with  which  the  embryo  is  provided,  tend 
also  to  individualize  in  a  greater  and  greater 
degree  the  animals  which  experience  them. 
As  an  instance  of  this  phenomenon  we  may 
quote  the  disappearance  of  the  eyes  in  certain 
Haustellate  and  certain  Edriophthalmian  Crus- 
taceans, and  that  of  the  greater  number  of  the 
extremities  in  a  great  many  of  the  Lerneae. 
The  Dromiae,  among  the  Decapod  anomoura, 
have  also  presented  us  with  an  instance  of 
changes,  analogous  in  their  nature  and  in  their 
consequences;  for  among  the  young  animals 
the  abdomen  terminates  in  a  caudal,  fan- 
shaped  fin,  as  among  all  the  Macroura  and 
a  great  many  of  the  Anomoura ;  but  with  the 
advance  of  age,  the  lateral  laminae  of  this 
organ  disappear,  and  the  abdomen  then  termi- 
nates very  nearly  as  it  does  in  the  Brachyura. 

It  is  among  the  Crustacea  which  are  born  in 
the  most  imperfect  state,  and  which  conse- 
quently have  the  greatest  number  of  changes 
to  undergo,  that  the  young  animals  bear  the 
greatest  resemblance  to  one  another.  The 
anomalies  of  conformation  encountered  among 

*  J  urine,  Histoire  dcs  Monocles. 


these  Crustacea  do  not  in  general  show  them- 
selves till  the  latter  periods  of  tlu-ir  Drouth. 

The  length  of  this  article  (already,  perhaps, 
too  great)  does  not  allow  of  our  pausing  longer 
on  this  subjeet,  and  we  shall  only  add  that  the 
evolution  of  the  Crustacea  is  one  of  the  points 
in  the  history  of  these  animals  which  ;»].; 
to  promise  the  most  interesting  and  important 
series  of  facts  to  whoever  will  devote  himself  to 
the  comparative  and  extended  investigation  of 
the  subject.* 

BIBLIOGRAPHY.— Besides  the  references  at  the 
bottoms  of  the  preceding  columns,  sec  Suchow,  Anat. 
physikalisch  Untcrsuchung  ueber  Insckten  und  Crus- 
tenthierc,  4to.  Heidelb.  1818.  Porting,  De  cancri 
fluviatilis  partibus  genitalibus,  Miscel.  Acad.  Natur. 
Curios.  Dec.  2,  An  1687,  p.  48.  Gesecke,  DC 
cancri  astaci  quibusdam  partibus,  4to.  Gotting. 
1817.  Kvhler,  Obs.  nonnulas  anatomicas,  &c.  et 
in  systema  vucorum  cancri  astaei,  8vo.  Tubing. 
1811.  Herbst,  Naturgeschte  der  Krabben  und 
Krebse,  3  Th.  4to.  Bcrl.  1782-1800.  Miiller,  En- 
tomostraca  sen  insecta  testacea,  &c.  4to.  Koprnh. 
1785.  Ramdokr,  Beytrage  zur  Naturgeschicbte 
einiger  deutschen  Monoculusarten,  8vo.  Halle, 
1805.  Hunter,  Catalogue  of  the  Hunterian  Col- 
lection in  the  Museum  of  the  Royal  College  of 
Surgeons — Comparative  Anatomy  and  Physiology, 
4to.  1831-5. 

(H.  Milne  Edwards,  j 

CYST.  Kystus,  (KVO-TK;,  bladder).  Certain 
membranous  investments,  of  various  forms, 
though  commonly  spheroidal,  being  shut  sacs, 
and  developed  in  the  midst  of  other  tissues, 
have  obtained  the  name  of  cysts. 

Up  to  the  present  moment  the  study  of  cysts 
is  so  little  advanced  that  we  can  scarcely  dis- 
cover any  researches  which  would  appear  to  be 
founded  upon  the  observation  of  nature.  Whilst 
so  much  attention  has  been  devoted  to  the  in- 
vestigation of  many  departments  of  patholo- 
gical anatomy,  it  is  difficult  to  understand  why 
this  very  interesting  subject  has  been  compara- 
tively neglected.  The  singularity  of  the  cir- 
cumstance is  not  lessened  by  the  reflection  that 
the  rules  of  therapeutics  ought  to  vary  with  the 
character  of  these  sacs,  and  that,  consequently, 
the  anatomical  study  is  of  first-rate  importance 
in  enabling  us  to  proceed  rationally  in  the  treat- 
ment of  these  extraordinary  products  of  the  ani- 
mal economy. 

In  describing  these  organs,  two  modes  have 
commonly  been  employed ;  the  one,  to  con- 
sider them  with  reference  to  the  product  they 
contain  ;  the  other,  with  reference  to  their  pro- 
per structure.  It  is  not  our  intention  to  adopt 
either  of  these  methods  of  considering  the  sub- 
ject, and  for  the  following  reasons: — it  is  de- 
monstrable that  cysts  which  are  identical  in 
texture  frequently  envelope  totally  different 
products,  and  also  that  the  products  and  the 
cysts  are  susceptible  of  transformation  to  an 
almost  indefinite  extent ;  and  as  neither  method 

*  See  on  this  subject  the  observations  of  Rathke 
already  quoted  ;  those  of  Thompson,  "  the  Meta- 
morphoses of  the  Crustacea;"  our  own  "  Rc- 
cherches  sur  les  changemens  de  forme  quo  les 
Crustacea  subissent  dans  le  jeune  age."  (Annalrs 
des  Sciences  Naturelles,  torn.  xxx.  and  2ne  scric, 
torn,  iii.)  and  the  inquiries  of  Nordmann  in  his 
Mikrographische  Bcitrage,  &c.  2tes  Heft. 


788 


CYST. 


affords  us  any  facility  in  distinguishing  one 
kind  of  cyst  from  another,  we  hold  them  alike 
inadequate  to  lead  to  correct  views  of  the  sub- 
ject. The  plan  which  we  propose  to  follow 
may  not  afford  any  increased  facility  in  dia- 
gnosis, but  it  is,  we  apprehend,  founded  upon 
a  more  stable  basis  than  either  of  those  to 
which  allusion  has  been  made.  We  mean  to 
consider  cysts  with  reference  to  the  mode  of 
their  developement;  and  although  we  do  not 
pretend  that  this  arrangement  will  afford  much 
greater  facility  than  at  present  exists  for  the 
diagnosis  of  the  species,  yet  it  appears  to  us  to 
be  the  most  natural  classification  which,  in  the 
present  state  of  our  knowledge,  we  are  enabled 
to  offer.  A  considerable  assistance  in  the  dia- 
gnosis of  these  organs  may  be  obtained  from 
the  adoption  of  the  following  principles,  which, 
though  not  unerring  in  their  application,  will 
afford  a  very  near  approximation  to  the  truth, 
in  the  majority  of  cases.  Those  firsts  which 
are  external,  subcutaneous,  and  exactly  glo- 
bular, with  a  thinning  of  the  dermis,  which 
seems  to  adhere  to  their  surface,  commonly 
contain  sebaceous  matter  of  a  whitish  colour, 
friable  and  semi-concrete  ;  those  which  occupy 
muscular  interstices  in  the  neck,  the  back,  or 
the  extremities,  have,  commonly,  thin  parietes, 
are  cellulous,  of  irregular  form,  and  contain 
either  serosity  or  albuminous  pus,  in  which 
are  seen  floating  opaque  flocculent  particles ; 
those  which  surround  articulations  and  ten- 
dinous sheaths — true  appendices  of  synovial 
tissues — are  strengthened  externally  by  fibrous 
laminae,  lined  by  a  serous  tissue,  and  contain  a 
more  or  less  pure  synovial  fluid ;  those  which 
are  developed  under  the  anterior  annular  liga- 
ment of  the  carpus  sometimes  contain  small 
whitish  bodies,  in  appearance  not  unlike  a 
grain  of  boiled  rice ;  those  which  occupy  in- 
ternal cavities,  attaching  particularly  to  the 
liver,  usually  contain  hydatids,  and  to  the 
ovary  contain  a  variety  of  products,  sometimes 
serous,  sometimes  sanguinolent,  sometimes 
gelatinous. 

Until  a  better  method  of  diagnosis  is  pre- 
sented, the  situation  of  the  organ  will  therefore 
facilitate  to  some  extent  the  knowledge  of  its 
contents.  No  one,  however,  will  rest  satisfied 
with  this  means,  nor  underrate  the  necessity  of 
pursuing  the  investigation  of  these  organs,  until 
we  are  in  a  condition  to  state  with  more  cer- 
tainty the  elements  for  their  diagnosis. 

We  believe  that  all  cysts  may  be  ranged 
under  one  of  the  three  following  categories.  A 
cyst  may  be  a  simple  enlargement,  or  exagge- 
rated developement,  or  other  modification  of 
an  existing  organ.  It  may  be  produced  by  the 
irritation  excited  by  the  presence  of  a  foreign 
body,  whether  that  body  be  a  shot  or  other 
substance  introduced  from  without,  or  a  tu- 
bercle or  other  abnormal  product  developed 
within  the  body.  It  may  be  a  new  formation 
not  before  existing  in  the  economy,  and  pre- 
existent  to  the  matter  which  it  may  be  after- 
wards found  to  contain. 

The  last  of  these  categories  has  not  usually 
constituted  an  element  in  the  consideration  of 
the  mode  of  formation  of  cysts,  and  the  sub- 
ject has  in  this  #ay  been  divested  of  the 


difficulties  which  it  must  otherwise  present. 
Many  accurate  observers  have  expressed  a 
belief  that  cysts  were  a  consequence  of  the 
irritation  occasioned  by  a  foreign  body ;  in  this 
way  a  large  proportion  of  these  organs  must 
be  entirely  excluded  from  consideration,  or 
must  be  treated  of  under  the  term  acephalocyst. 
Another  class  of  observers,  admitting  the  exist- 
ence of  the  foregoing,  have  added  another 
variety : — they  have  assumed  that  the  parietes 
of  an  alveolus  of  cellular  tissue  are  attacked  by 
some  "morbid  affection"  by  which  all  com- 
munication with  the  adjoining  cells  is  cut  off; 
that  the  parietes  of  this  alveolus,  under  the  in- 
fluence of  irritation,  acquire  the  power  of  secret- 
ing a  product  entirely  different  from  that  which 
they  furnish  in  their  natural  condition ;  that  the 
accumulation  of  this  morbid  product  causes 
a  progressive  distention  of  this  small  cavity,  and 
a  thickening  of  the  cellular  laminae  in  the  midst 
of  which  the  tumour  is  developed :  in  other 
words,  that  the  tumour  so  produced  acts  in 
the  same  manner  as  a  shot  or  other  body  in- 
troduced from  without.  In  the  opinion  that 
all  cysts  are  so  produced,  they  are  fortified  by 
the  belief  that,  by  the  process  of  maceration,  of 
inflammation,  or  of  suppuration,  it  is  possible 
to  reduce  the  parietes  of  these  organs  to  their 
"  original  element,  cellular  tissue."  Such  was 
the  opinion  of  Morgagni,  Haller,  Louis.  The 
opinion  propagated  by  Bichat,  that  a  certain 
uniformity  in  structure  obtains  in  all  cysts, 
that  they  are  all  analogous  to  serous  mem- 
branes, will,  it  is  believed,  be  found  incorrect ; 
there  are  many  cysts  which  in  structure  and 
function  are  essentially  different  from  serous 
tissues,  for  instance,  some  are  fibrous,  cartila- 
ginous, osseous,  others  are  cutaneous,  others 
covered  with  hair. 

Our  first  class  contains  the  greater  number 
of  those  subcutaneous  tumours  which  are  so 
commonly  seen  under  the  integuments  of  the 
cranium,  the  face,  and  some  other  parts  of  the 
body,  and  which  contain  meliceric,  athero- 
matous,  steatomatous,  or  other  matter.  It  has 
been  over  and  over  again  demonstrated  that 
those  follicles  which  open  upon  the  surface  of 
the  body  may  have  their  aperture  obliterated  : 
the  secretion  from  the  internal  surface  of  the 
organ  may  still  proceed,  and  they  occasionally 
attain  a  considerable  volume;  in  this  way 
"steatomatous"  tumours  are  produced.  The 
matter  contained  in  these  tumours  has  been 
analysed  by  Thenard,  who  obtained  the  fol- 
lowing results. 

One  hundred  parts  submitted  to  desiccation 
were  reduced  to  forty,  which  treated  by  alcohol 
were,  in  fact,  dissolved  :  the  alcohol  in  cooling 
deposited  a  fatty  matter,  which  was  easily 
melted  and  was  similar  to  adipocire.  The 
residuum,  which  formed  sixteen  parts,  was  of 
an  albuminous  nature;  consequently  there  were 
twenty-four  parts  of  adipocire.  This  adipocire 
did  not  crystallise  like  that  of  the  biliary  cal- 
culus in  man ;  it  was  deposited  in  flakes  like 
those  of  putrid  animal  matter  dissolved  in 
alcohol :  yet,  in  the  matter  of  the  cyst,  it  was 
in  the  form  of  very  brilliant  micaceous  laminae. 
These  cysts  frequently  appear  very  thick,  but 
thi«  great  thickness  is  a  consequence  of  their 


CYST. 


789 


being  almost  constantly  lined  by  an  inorganic 
coat,  which  is  sometimes  susceptible  of  being 
divided  into  laminae ;  when  this  coat  is  re- 
moved, there  remains  a  very  thin  cellular  mem- 
brane. If  the  lining  membrane  be  irritated, 
the  secretion  as  well  as  the  membrane  may  be 
modified  ;  and  the  variety  of  these  subcuta- 
neous tumours  is  thus  explained. 

Other  cysts  differently  formed  appear  to  ar- 
rangfe  themselves  most  naturally  in  this  class  ; 
of  such  are  those  which  succeed  to  the  ob- 
struction of  a  salivary  duct,  ranula  for  instance  ; 
those  which  succeed  to  a  fistulous  canal,  and 
are  produced  by  the  obliteration  of  the  orifices 
of  such  canal ;  the  mucous  tissue  by  which 
the  canal  was  previously  invested  becomes 
changed  in  its  organization,  and  a  serous  cha- 
racter is  acquired : — those  which  are  occasionally 
produced  in  the  lungs,  by  the  obliteration  of 
the  canal  of  communication  between  a  tuber- 
cular cavity  and  a  bronchus ;  in  this  case 
also  a  serous  membrane  is  developed  within 
the  cavity. 

The  second  class. — Every  foreign  body,  fluid 
or  solid,  formed  within  or  derived  from  with- 
out the  animal  economy,  induces  in  that  eco- 
nomy an  effort  at  expulsion.  Whether  the 
body  be  a  shot,  a  bullet,  or  other  projectile,  or 
whether  it  be  extravasated  blood,  stone  in  the 
bladder,  the  foetus  in  extra-uterine  pregnancy, 
acephalocysts,  tubercle,  or  other  heterologous 
or  analogous  formation ;  in  all  cases  irritation 
or  inflammation  is  developed,  for  the  purpose 
of  expelling  or  isolating  the  nocuous  body. 
If  it  be  in  its  nature  irritating,  it  excites  in- 
flammation, and  is  expelled  with  the  pus  which 
has  been  secreted  around  it;  if  it  have  no 
mechanically  or  chemically  irritating  property, 
it  may  remain  in  the  midst  of  the  organ,  some- 
times passing  from  cell  to  cell,  obedient  al- 
ways to  a  kind  of  eccentric  movement ;  some- 
times nature  isolates  it  by  organising  around  it 
a  cyst  which  is  adherent  by  its  external  surface 
to  the  surrounding  tissues,  but  which  is  free 
and  smooth  internally, — furnishing  a  fluid  by 
which  many  of  these  bodies  may  be  broken 
down,  and  as  soon  as  they  are  removed,  the 
walls  of  the  cyst  become  reduced  into  cellular 
tissue  by  absorption. 

Frequent  opportunities  are  afforded  for  ex- 
amining these  structures  in  the  cellular  tissue. 
When  a  certain  quantity  of  a  succulent  fluid  is 
accumulated  in  this  structure,  if  it  cease  to 
increase,  the  parietes  of  the  cavity  which  con- 
tains it  continues  to  be  the  seat  of  a  chronic 
inflammation  by  which  the  formation  of  a  cyst 
is  determined.  Until  the  organisation  of  this 
cyst  is  perfected,  the  surrounding  cellular  tissue 
continues  red  and  indurated;  but  as  soon  as 
the  organ  is  completed,  this  redness  and  in- 
duration are  commonly  in  progress  of  dis- 
sipation ;  in  some  cases,  however,  they  remain, 
and  then  it  occasionally  happens  that  the  cyst 
participates  in  the  morbid  action,  and  the  in- 
terior of  the  cyst  may  have  a  pseudo-membrane 
developed  on  its  surface.  Cysts  so  developed 
are  at  their  commencement  soft,  not  very  con- 
sistent, and  may  be  easily  detached  from  the 
surrounding  structure.  The  inflamed  stratum, 
between  the  cyst  and  the  adjacent  healthy 


tissue,  gradually  acquires  a  greater  density  and 
more  power  of  resistance,  ;tt  the  same  time 
that  it  becomes  thinner,  and  contracts  a  more 
intimate  union  with  the  proper  membrane  of 
the  cyst.  When  the  organisation  of  this  spe- 
cies of  cyst  is  completed,  the  membrane  is 
whitish,  opaque,  more  or  less  thick,  and  as  a 
point  of  comparison,  denser,  and  thicker  th;m 
a  serous  membrane,  and  it  presents  a  surface 
somewhat  similar  to  that  membrane. 

In  making  a  third  class,  it  must  be  obvious 
that  we  incline  to  the  opinion  of  Delpech, 
"  that  certain  cysts  do  not  proceed  from  an 
accidental  and  mechanical  modification  of  the 
cellular  tissue,"  but  that  they  are  so  many  new 
organs,  so  many  newly  developed  tissues, 
which  do  not  possess  either  the  same  degree  or 
even  the  same  kind  of  vitality  as  the  surround- 
ing parts. 

In  this  class  we  range  those  which  contain 
a  serous  or  sero-mucous  fluid,  which  are  de- 
veloped in  various  parts  of  the  body.  Their 
parietes  are  sometimes  transparent,  at  others 
opaque ;  upon  their  inner  surface  they  usually 
present  a  kind  of  tomentum  or  velvet-like  tex- 
ture, sometimes  it  presents  hair.  Their  ex- 
ternal surface  is  sometimes  free  on  all  sides 
except  that  upon  which  the  vascular  commu- 
nication obtains,  sometimes  they  are  com- 
pletely adherent.  They  are  observed  free  and 
almost  floating  in  the  cerebral  cavities,  in  the 
kidney,  the  liver,  the  lungs,  and  in  all  serous 
cavities. 

We  also  include  in  this  class  certain  syno- 
vial  cysts,  which  are  observed  around  the 
articulations  of  the  hand,  of  the  foot,  some- 
times of  the  knee,  and  in  the  neighbourhood 
of  the  sheaths  of  tendons.  Some  persons  have 
been  disposed  to  refer  the  origin  of  these 
organs  to  a  displacement  of  the  synovial  mem- 
brane which  has  yielded  at  this  point;  but  ob- 
servation has  demonstrated  that  they  are  cysts 
with  dense  and  fibrous  external,  and  serous 
internal  parietes,  developed  in  the  cellular 
tissue  surrounding  the  normal  synovial  sac. 

In  the  same  class  we  place  a  species  of  cyst 
developed,  so  far  as  we  yet  know,  under  the 
anterior  annular  ligament  of  the  carpal  articu- 
lation,—  more  rarely  in  the  vicinity  of  the 
tibio-tarsal  articulation,  but  always  around  sy- 
novial sacs  or  tendons,  and  essentially  con- 
stituted of  small  white  bodies,  in  appearance 
similar  to  small  grains  of  boiled  rice. 

Of  the  serous  cysts,  we  may  frequently  find 
some  very  small,  and,  as  nearly  as  may  be, 
empty,  the  membrane  being  puckered  and 
plicated,  and  in  contact  with  itself  at  points 
where  the  plicae  meet.  At  a  certain  period  of 
their  existence  there  is  scarcely  a  particle  of 
fluid  accumulated  in  them,  and  of  course  the 
first  exaggerated  exhalation  which  has  place 
will  be  lodged  without  any  obstacle  in  the 
cavity,  the  plicae  will  be  effaced,  and  the  pa- 
rietes removed  to  a  certain  distance,  the  one 
from  the  other.  It  is  probable  that  this  pro- 
portion between  the  cyst  and  its  contents  is 
maintained  until  some  irritation  shall  acce- 
lerate the  exhalation,  much  as  in  the  serous 
cavities  of  the  body.  This  exhalation  is  some- 
times so  abundant  and  rapid  that  the  parietes 


790 


CYST. 


become  irritated  and  inflamed,  and  these  tunics, 
at  first  characterised  by  so  much  tenuity,  may, 
by  the  pure  and  simple  effect  of  their  rapid 
development,  or  as  a  consequence  of  their 
relation  with  very  moveable  organs,  or  by  the 
effect  of  accident,  to  which  they  are  exposed, 
become  susceptible  of  almost  unlimited  trans- 
formation. 

We  believe,  therefore,  that  ail  the  varieties 
composing  this  class  owe  their  existence  to 
irritation  ;  in  the  synovial  the  irritation  is  spe- 
cific and  caused  by  pressure, — in  the  serous, 
we  believe  it  to  be  of  another  kind, — in  many 
of  them  it  is  similar  to  that  which  presides 
over  the  development  of  hydatids:  the  only 
difference  between  certain  of  them,  those,  for 
instance,  which  are  so  nearly  isolated,  having 
merely  a  vascular  communication,  and  an 
hydatid,  is  perhaps  simply,  that  their  existence 
has  not  been  sufficiently  prolonged  to  permit 
with  safety  the  rupture  of  this  umbilical  cord, 
if  I  may  so  term  it,  by  which  they  are  con- 
nected to  the  surrounding  tissues  ?  We  must 
now  endeavour  to  explain  the  circumstances 
under  which  these  cysts  are  developed. 

The  experiments  and  observations  of  Cru- 
veilhier  shew,  in  the  most  convincing  manner, 
that  humidity,  abundance,  and  the  bad  or  ve- 
getable quality  of  the  nourishment  of  an 
animal,  are  unequivocal  means  of  producing 
acephalocysts.  If  by  the  concurrence  of  these 
circumstances  acephalocysts  may  be  produced, 
it  must  be  evident  that  by  the  agency  of  the 
same  causes  a  modification  of  existing  tissues, 
— irritation,  in  fact,  of  a  specific  kind,  has  been 
excited  by  which  a  state  favourable  to  their 
development  has  been  produced.  Admitting 
then  that  by  such  means  a  particular  kind  of 
irritation  may  be  set  up  in  certain  tissues,  we 
must  go  further;  that  irritation  must  be  suf- 
ficient to  cause  the  exhalation  of  a  particle  of 
lymph,  that  lymph,  as  in  the  case  of  a  pseudo- 
membrane,  becomes  organised,  acquires  step 
by  step  an  individual  existence,  it  will  be  the 
minimum  of  organisation  and  independent 
vitality,  but  still,  when  its  separation  is  achieved, 
it  will  be  a  living  being.  Supposing  this  idea 
to  be  correct,  it  may  follow  that  a  variety  of 
modifications  of  such  products,  more  or  less 
independent,  may  be  in  a  similar  manner  pro- 
duced. 

It  is  certainly  difficult  to  reconcile  the  mind 
to  the  idea  that  the  process  of  irritation  or  of 
inflammation  can,  under  any  circumstance, 
excite  the  development  of  an  animal  possess- 
ing to  a  certain  extent  an  independent  ex- 
istence, but  this  is  not  more  difficult  than  to 
conceive  that  molecules  of  a  plastic  living 
substance  may  form  organic  membranes,  and 
,yet  this  is  demonstrable. 

This  has  been  clearly  shewn  in  the  article 
ADHESION;  in  fact,  the  more  we  study  the 
phenomena  of  organisation,  the  more  we  are 
impelled  to  admit  a  proper  vitality  in  certain 
products  of  living  bodies.  The  analogy  which 
exists  between  false  membranes  and  hydatid 
sacs  appears  to  be  especially  calculated  to 
elucidate  this  subject.  But  whilst  the  false 
membrane  remains  in  vital  communication  with 
the  individual,  the  acephalocystic  false  mem- 


brane is  detached  and  enjoys  an  independent 
life ;  the  false  membrane  acquires  a  vitality 
rivalling  that  of  normal  tissues. 

We  believe,  therefore,  that  a  cyst  may  be 
developed,  which,  as  far  as  general  appearances 
are  concerned,  shall  be  analogous  to  the  ace- 
phalocysts, wanting,  however,  the  one  great 
attribute,  independent  existence,  and  having 
a  vascular  communication  with  the  tissue  upon 
which  it  is  developed  :  are  not  those  cysts 
which  are  often  seen  upon  the  cortical  sub- 
stance of  the  kidney,  and  upon  other  organs; 
of  this  class  or  character  ? 

Dr.  Hodgkin*  has  inferred  that  those  cysts 
which  are  so  often  found  on  the  surface  of  the 
kidneys  owe  their  existence  to  the  obstruction 
of  an  excretory  canal;  others  have  believed 
that  this  fact  was  demonstrated,  because  it  was 
said  that  their  contents  had  the  odour  of  urine. 
Without  denying  this  position,  I  may  state 
that  the  smell  of  serum  and  that  of  limpid 
urine  are  not  very  dissimilar.  If  they  were  a 
consequence  of  the  obstruction  of  an  urinary 
duct,  it  is  evident,  from  the  size  they  some- 
times attain,  that  secretion  has  proceeded  after 
the  obstruction  has  been  developed  ;  why  then 
does  it  not  go  further  ?  why  do  they  not  attain 
considerable  magnitude  ? 

In  the  earlier  periods  of  their  existence  the 
organisation  of  these  bodies  is  simple,  but  in 
their  progress  they  may  experience  many  mo- 
difications. Their  internal  and  external  sur- 
faces are  essentially  different;  the  internal  is 
usually  smooth  and  polished  like  serous  mem- 
branes;  sometimes  it  is  soft,  flocculent,  and 
easily  detached  :  the  external  is  in  contact  with 
cellular  tissue,  and  partakes  more  or  less  of  its 
character,  but  frequently  it  acquires  a  density 
which  distinctly  separates  it  from  the  surround- 
ing tissue.  There  is  scarcely  any  form  of  trans- 
formation which  may  not  occur  in  these  organs. 
The  internal  surface  occasionally  acquires  a 
very  complicated  organisation  ;  it  may  be  co- 
vered with  hair  proceeding  from  follicles  de- 
veloped in  its  parietes,  and  it  may  present 
other  anomalies.  The  external  surface  may 
acquire  a  very  considerable  density,  and  may 
present  something  like  a  fibrous  appearance, 
but  upon  further  investigation  we  find  that  it 
does  not  possess  any  fibre,  neither  does  its 
texture  offer  any  linear  or  radiated  arrange- 
ment. When  once  organised,  the  tunic  which 
constitutes  the  cyst  enjoys  all  the  attributes 
of  living  tissues,  and  is  susceptible  of  similar 
morbid  modifications.  It  may  become  in- 
flamed, it  may  degenerate  into  a  cartilaginous 
state, — may  become  incrusted  with  phosphate 
of  lime,  converted  into  erectile  tissue, — may 
become  scirrhous,  and  so  on ;  and  the  ex- 
halation or  secretion  may  be  so  changed  that 
cysts  of  similar  origin  may  contain  the  most 
dissimilar  products. 

BIBLIOGRAPHY. — Cruveilhier,  Essai  sur  1'Anat. 
Path.  t.  i.  p.  202  &  seq.  Gendrin,  Hist.  Anat. 
des  Inflam.  t.  ii.  p.  531.  Begin,  Diet,  de  Med.  et 
Chir.  Path.  art.  Kyste. 

(B.  Phillips.) 


*  Med.  Chir,  Transact,  vol.  xv.  part  2.  p.  270. 


DEATH. 


791 


DEATH.— (Lat.  mors;  Gr.  0<i»aTos;  Germ. 
Tod;  Fr.  mort ;  Ital.  morte.)  This  word  has 
acquired  a  variety  of  meanings,  which  it  will 
be  proper  to  enumerate,  before  explaining 
the  sense  to  be  adopted  in  the  following- 
article. — Death  sometimes  expresses  the  time 
when  an  organic  body  loses  the  characters 
which  distinguished  it  while  living ;  in  which 
signification  it  is  the  opposite,  not  of  life, 
but  of  birth,  or  the  period  when  life  began ; 
this  period  being  dated  in  the  animal  either 
from  the  time  when  it  left  its  ovum  or  its 
parent,  or  from  the  very  moment  of  con- 
ception; and  in  the  vegetable,  either  from 
its  emergence  above  the  earth,  or  from  the 
first  impulse  of  germination.  In  another 
acceptation,  Death  is  that  altered  condition 
of  an  organic  body  in  which  it  is  no  longer 
the  subject  of  certain  processes  which  con- 
stituted its  life.  Thirdly,  it  may  signify  that 
series  of  changes  which  immediately  precede 
the  cessation  of  life ; — in  this  meaning,  death 
is  the  act  or  process  of  dying.  Lastly,  in  the 
human  subject,  the  word  is  employed  to  express 
the  separation  of  the  soul  from  the  body.  It 
will  be  our  object  not  so  much  to  follow  out 
these  several  significations,  which  would  lead 
into  a  very  wide  if  not  a  vague  discussion,  as 
to  consider  the  precise  nature  of  that  condition 
of  the  animal  body  to  which  the  term  Death 
in  its  physiological  import  is  applicable,  and 
to  enquire  by  what  signs  that  state  may  be 
known  to  be  either  impending,  or  actually 
present. 

Death  in  its  most  restricted  sense  may  be 
defined  to  be  that  condition  which  imme- 
diately succeeds  the  abolition  of  all  those  ac- 
tions or  properties  which  distinguish  living 
from  brute  matter,  a  condition  not  merely 
negative  but  privative.  But  death  is  likewise 
applied  to  certain  states  of  the  organic  system 
in  the  higher  animals,  in  which  the  abolition 
of  the  functions  is  not  universal.  In  the 
former  sense,  an  animal  is  not  dead  until 
every  vital  action  throughout  the  tissues  has 
been  extinguished;  while  in  the  latter,  dis- 
solution is  considered  to  have  taken  place 
when  the  circulation  and  respiration  have 
ceased,  because  the  cessation  of  the  others 
almost  uniformly  follows.  We  have  here 
then  an  obvious  distinction  of  Death  into  two 
kinds,  which  will  be  found  to  correspond 
with  a  very  natural  division  of  the  vital  actions 
into  two  classes;  1,  those  which  transpire 
between  the  particles  of  which  living  bodies 
are  composed  (nutrition  and  contraction);  and 
2,  those  which  occur  between  certain  collec- 
tions of  organic  particles,  called  organs,  and 
by  virtue  of  which  these  organs  constitute  a 
whole  system — (respiration,  circulation,  inner- 
vation,  &c.)  The  extinction  of  the  former  of 
these  classes  of  functions  we  shall  venture  to 
designate  Molecular  Death;  of  the  latter, 
Systemic  Death* 

*  We  should  have  been  glad  to  have  avoided  a 
word  so  incorrectly  formed  as  systemic,  but  its  use 
has  been  sanctioned  by  too  many  and  too  great  au- 
thorities for  us  to  venture  upon  the  substitution  of 


The  following  truths  respecting  the  mutual 
influence  of  these  two  kinds  <>!'  death  will  be 
illustrated  in  the  course  of  tin-  piv<mt  article  : 
1st,  That  molecular  does  not  necessarily  in- 
volve systemic  death,  unless  the  former  is 
universal.  2dly,  That  when  partial. 
mortification,  the  tendency  of  molecular  to  in- 
duce systemic  death  depends  on  the  import- 
ance of  the  part  to  the  whole.  3dly,  That 
molecular  death  in  one  part  can  only  induce 
the  same  change  in  another  part,  by  means  of 
its  interference  with  one  of  the  systemic  func- 
tions. 4thly,  That  systemic  death  must  neces- 
sarily be  followed  sooner  or  later  by  molecular 
death, — but  that,  5thly,  The  reality  of  systemic 
death  can  only  be  proved  with  certainty  by 
the  occurrences  pertaining  to  molecular  death. 

MOLECULAR  DEATH. 

Molecular  life  is  constituted  by  two  func- 
tions. Nutrition  and  Contraction,  for  which 
certain  conditions  are  requisite.  The  former 
demands  a  mechanism  or  tissue  of  pores  or  in- 
finitely minute  tubes,  the  ingress  and  egress 
of  fluid,  and  a  certain  quality  of  this  fluid; 
the  latter,  a  fibrous  arrangement  of  particles, 
in  most  animals  and  in  all  a  peculiar  property 
called  irritability  or  contractility.  The  viola- 
tions of  these  conditions  are  necessarily  fol- 
lowed by  molecular  death.  We  shall  consider 
them  in  detail. 

Destruction  of  the  tissues. — It  is  all  but  a 
truism  to  assert  that  the  function  of  a  tissue 
must  cease  when  its  mechanism  is  broken  up, 
though  mere  integrity  of  the  mechanism  is 
insufficient  to  maintain  the  function.  The 
changes  which  ensue  are  as  follows.  The  sub- 
stance is  no  longer  capable  of  receiving  and 
transmitting  fluid  in  the  same  manner  as  for- 
merly ;  the  fluid  which  it  contained  is  either 
confused  with  the  disorganized  solid  particles,  or 
is  altogether  eliminated  ;  the  fibres  are  unfitted 
for  contraction ;  and  the  nervous  filaments  are 
paralysed.  In  this  condition  the  part  has  ob- 
viously no  kind  of  connection  with  the  rest  of 
the  system,  by  the  exchange  either  of  fluid,  or 
of  nervous  influence;  it  is  dead  both  abso- 
lutely and  relatively.  If  the  other  organs  sur- 
vive its  death,  certain  processes  commence  in 
its  immediate  vicinity,  by  means  of  which  a 
mechanical  as  well  as  a  vital  separation  is 
effected ;  while  the  mortified  part,  as  it  is 
technically  called,  is  abandoned  to  the  play  of 
various  chemical  affinities  among  its  particles, 
and  between  these  and  surrounding  agents. 
According  as  these  changes  are  less  or  more  ad- 
vanced, there  is  gangrene  or  sphacelus.  It 
may  happen  however  that  the  other  parts  of 
the  frame  may  lose  their  vitality  soon  after  the 
local  injury  ;  but  their  dissolution  will  depend 
upon  the  violation  of  other  conditions  than 
that  which  we  are  at  present  discussing. 
Thus  the  part  disorganized  may  be  essential 

a  newly-created  one.  The  writer  is  indebted  to  his 
friend  Dr.  Prichard  for  the  suggestion  of  somatic, 
which  is  at  once  correct,  and  sufficiently  characte- 
ristic, but  he  has  not  had  the  courage  to  introduce 
it  into  the  text,  though  supported  by  an  authority 
no  less  eminent  in  philology  than  in  general  sci- 
ence. 


792 


DEATH. 


to  the  distribution  of  blood  throughout  the 
system,  and  the  other  parts  may  die  from  the 
want  of  this  supply,  their  mechanism  remain- 
ing entire.  Or  the  injury,  notwithstanding 
that  the  part  may  not  be  thus  functionally  es- 
sential to  the  circulation,  may  exert  a  no  less 
certain  operation,  either  indirectly  by  an  im- 
pression made  upon  the  central  organs  of  in- 
nervation,  and  reflected  upon  those  of  circu- 
lation and  respiration,  or  immediately  by  an 
impression  upon  the  latter.  (See  the  remarks 
upon  Systemic  Death.)  The  propagation 
of  the  dissolution  will  depend  much  upon  the 
peculiar  organization  of  the  animal;  but  in 
all  cases,  as  we  have  already  intimated,  text- 
ural  death  in  one  part  has  no  immediate  in- 
fluence in  producing  the  same  kind  of  death 
in  other  parts ;  the  latter  event  will  be  found 
attributable  to  the  impediment  offered  by  the 
former  to  some  important  function  of  the 
whole  system.  The  textural  lesion  which  we 
have  been  considering  may  be  caused  either  by 
mechanical  violence,  or  by  chemical  action, 
such  as  that  of  corrosive  substances  and  of 
heat.  It  is  possible  that  solid  tissue  may  un- 
dergo spontaneous  decomposition,  but  we  are 
unable  to  ascertain  the  fact,  because  in  ulti- 
mate structure,  where  fluids  and  solids  are  so 
intimately  intermixed,  we  have  no  means  of 
distinguishing  the  priority  of  changes. 

Arrest  of  the  fluid  of  nutrition. — The  access 
of  this  fluid  is  variously  provided  for  in  the 
different  classes  of  animals.  The  capillary  cir- 
culation in  the  higher  species  resembles  that 
which  suffices  for  the  whole  system  in  the 
lower  species,  inasmuch  as  the  blood  in  the 
capillaries  of  a  tissue  bears  the  same  relation 
to  that  tissue,  as  the  water  in  the  stomach  of 
one  of  the  Radiata  to  the  whole  animal.  The 
consequences  of  abstracting  the  fluid  in  the  one 
case,  or  of  cutting  off  the  supply  of  blood  in 
the  other  by  obstructing  its  vessels,  will  be  pre- 
cisely analogous.  The  polype  will  desiccate, 
lose  its  proper  form,  and  decay;  the  medusa 
will  shrivel  and  putrefy;  while  in  man  the 
tissue  dies,  and  is  decomposed,  as  in  senile 
gangrene,  or  in  the  sloughing  of  a  hsemorrhoid 
to  which  a  ligature  has  been  applied.  Sup- 
pression of  the  action  of  the  heart  violates 
throughout  the  body  the  condition  of  vitality 
under  discussion,  and  consequently  all  the 
tissues  die,  but  the  phenomena  which  they 
exhibit  are  not  the  same  as  in  more  partial 
obstruction  of  the  circulation,  because  the 
chemical  agencies  are  different,  particularly 
that  of  surrounding  heat.  A  gangrenous  spot 
is  under  the  influence  of  an  atmosphere  of  98° 
at  the  lowest;  while  the  dead  or  dying  organs 
of  animals,  which  have  been  simultaneously 
deprived  of  their  circulation,  are  submitted 
only  to  the  temperature  of  the  media  in  which 
they  may  chance  to  be  placed.  The  higher 
this  may  be  within  certain  limits,  the  more 
closely  will  the  putrefactive  changes  resemble 
those  of  gangrene.  It  must  be  remembered, 
however,  that  in  the  latter  case  other  chemical 
agents  are  probably  presented  in  the  fluids 
effused  by  those  contiguous  parts  which  still 
maintain  their  vitality. 


Dependence  upon  the  circulation  differs  in 
different  animals.  The  heart  of  a  salamander 
may  be  excised,  and  yet  the  animal  will  live 
for  several  hours,  or  even  a  day  or  two  after 
the  operation  ;*  its  possession  of  life  being  in- 
ferred from  the  exhibition,  not  merely  of  cer- 
tain organic  actions,  but  even  of  those  of  rela- 
tion. It  is  plain,  then,  that  in  animals  of  this 
tribe,  the  brain  and  spinal  marrow  and  other 
organs  do  not  require  so  constant  an  inter- 
course with  the  blood  as  in  certain  other  species  ; 
and  while  we  know  with  tolerable  certainty 
that  they  do  not  need  it  for  calorific  purposes, 
it  is  not  improbable  that  their  textures  are  less 
frequently  repaired  than  those  of  the  warm- 
blooded classes.  Dr.  Edwards  concludes  that 
life  in  the  above  instance  is  maintained  by  the 
organs  of  innervation,  whose  function,  as  we 
have  remarked,  continues  unimpaired.  We 
should  regard  the  integrity  of  their  action 
rather  as  a  sign  than  as  a  cause  of  continued 
vitality ;  other  signs  being  perceptible  in  the 
persistence  of  the  capillary  actions,  for  which 
the  fluids  still  remaining  in  the  tissues  may  be 
sufficient. 

Retention  of  fluid  in  the  tissues. — Removal 
of  the  effete  fluid  is  provided  for  in  the  Porifera 
by  ejects;  in  the  Polypifera  by  expulsion  from 
the  central  cavity  and  by  transpiration ;  in  the 
Acalephse  by  anal  apertures ;  and  in  vascular 
animals  by  vessels  especially  appropriated  to 
the  purpose,  by  transpiration,  and  by  various 
excretions.  This  condition  of  molecular  life 
is  less  easily  violated  than  those  already  spo- 
ken of,  because  the  modes  of  fulfilling  it  are 
more  numerous.  This  is  equally  true  whether 
we  speak  of  the  simple  animal  forms,  or  of  the 
tissues  of  the  more  complicated ;  mortification 
is  less  frequently  the  result  of  venous  than  of 
arterial  obstruction.  Unquestionably  turgescence 
and  inflammation  may  ensue  from  the  former, 
and  may  terminate  in  gangrene ;  but  it  is  far 
more  common  for  the  part  to  be  relieved  by 
the  excretion  of  various  fluids,  constituting 
haemorrhage  and  dropsy,  until  new  channels  are 
found  for  the  returning  blood.  Hence  it  ap- 
pears that  a  redundance  of  fluid  is  less  dan- 
gerous to  organic  structures  than  a  deficiency. 

Depravation  of  the  fluid  of  nutrition. — It 
is  obvious  that  as  the  structures  are  elaborated 
either  from  the  blood  in  the  higher  animals,  or 
from  the  fluids  corresponding  to  it  in  the  in- 
ferior classes,  the  assimilative  processes  must 
be  deranged  and  ultimately  brought  to  a  stop, 
if  the  liquids  are  wanting  in  the  proper  mate- 
rials. Their  quality  may  be  deteriorated  in 
various  modes;  by  imperfect  respiration,  by 
bad  or  scanty  alimentation,  and  by  insufficient 
or  excessive  excretion.  Each  of  these  causes 
is  traced  easily  enough  in  the  degenerated  tex- 
tures of  some  animals,  but  with  more  difficulty 
in  the  simpler  classes,  because  the  functions 
just  alluded  to  are  not  in  the  latter  concen- 
trated within  a  space  that  admits  of  analysis  so 
well  as  in  the  former.  The  effect  of  obstructed 
aeration  of  the  blood  however  is  soon  mani- 

*  Edwards,  On  the  Influence  of  Physical  Agents, 
&e.  translated  by  Drs.  Uodgkin  and  Fisher. 


DI-ATll. 


Tested  even  in  the  lowest  grades.  But  we  must 
observe,  that  throughout  the  whole  range  of 
animal  existence  we  can  more  readily  ascertain 
the  changes  produced  in  molecular  action  by 
diminished  respiration,  than  by  the  entire  sus- 
pension of  this  function  ;  because,  in  the  first 
place,  the  arrest  of  the  circulation  so  soon  fol- 
lows that  of  respiration,  that  the  subsequent 
events  are  assignable  rather  to  the  former  than 
to  the  latter;  and  in  the  second  place,  it  is 
impossible  to  cause  one  portion  of  the  body 
to  receive  nnaerated,  while  the  others  are  sup- 
plied with  aerated  blood,  since  the  function  is 
in  some  animals  too  concentrated  to  allow  of  an 
operation  calculated  to  act  upon  an  isolated 
part,  and  in  other  animals  too  diffuse  to  enable 
us  to  interfere  with  it  effectually  in  any  given 
space.  In  the  one  case  we  run  the  risk  of 
cutting  off' the  supply  of  blood  from  the  whole 
animal ;  in  the  other  we  should  find  it  im- 
possible to  prevent  any  one  part  from  receiving 
from  other  parts  a  compensation  for  what  it 
loses  by  the  obstruction  of  its  own  particular 
allotment  of  the  respiratory  function.  Nothing 
however  is  more  common  than  to  witness  the 
degeneration  of  structure  produced  by  blood 
insufficiently  arterialized,  the  imperfection  of 
the  process  depending  either  upon  disorder  in 
the  organs  of  respiration,  or  upon  a  vitiated 
condition  of  the  atmosphere.  From  facts  of 
this  nature  it.  is  legitimate  to  infer  that  were  it 
possible  for  unarterialized  blood  to  circulate, 
the  death  of  the  tissues  must  sooner  or  later 
ensue.  Of  the  destructive  tendency  of  blood 
depraved  by  the  other  causes  above  enu- 
merated we  can  likewise  judge  approxima- 
tively ;  in  other  words,  while  there  can  be  no 
question  of  the  deterioration  of  structures  under 
the  operation  of  those  causes,  we  are  not  ac- 
quainted with  any  instances  in  which  we  can 
attribute  solely  to  their  agency  the  entire  cessa- 
tion of  molecular  actions.  It  almost  always 
happens  that  other  functions  have  previously 
failed,  and  influenced  the  result  in  question. 

Extinction  of  irritability. — Irritability  might 
at  first  seem  rather  the  result  of  vitality  than 
one  of  its  conditions  ;  but  whether  we  look  at 
the  textural  motions  in  a  complex  animal,  or  at 
their  analogues  in   the  entire   systems  of  the 
simpler  forms,  we  shall  find  irritability  to  be 
essential  to  the  continuance  of  those  processes 
in  which  living  action  consists.     The  alimen- 
tary cavity  which  contracts  upon  the  nutrient 
fluid  of  the  zoophyte  is  no  less  essential  to  the 
existence  of  the  latter,  than  a  similar  action  of 
capillary  tubes  in  the  tissues  of  mammalia.     In 
each  case  the  action  is  requisite,  in  order  to 
bring  the  particles  within  the  spheres  of  the 
textural  affinities.  The  extinction  of  irritability 
is  therefore  necessarily  productive  of  molecular 
death.     In  this  instance  we  are  compelled  to 
speak  of  the  privation  of  a  property  instead  of 
defining  the  actual  change  in  the  part,  because 
at  present  it  is  not  ascertained  what  condition 
of  the  part  is  capable  of  producing  contraction. 
Irritability  is  merely  an  expression  of  the  fact 
that  the  substance  of  which  it  is  predicated, 
undergoes  contractions  inexplicable  on  common 
physical  principles.     We  detect  nothing  in  the 
VOL.  r. 


substance,  the-  existence  of   which   enables  us 
to  pronounce  with  certainty  that  it  may  be  the 
subject  of  the  actions  alluded  to.     Some  have 
maintained   that   irritability   ought    to   be  ad- 
mitted as  an  ultimate  fact,  of  which  we  know 
as  much  as  of  gravity.     But  we  apprehend  that 
there  is  this  great  difference  in  our  knowledge 
of  the  two  properties,  viz.  that  although  igno 
rant  of  the  cause  of  the  attraction  of  gravitation, 
we  are  certain   that   the  phenomena  are  co- 
extensive with  the  essential  properties  of  mat- 
ter; but  we  are  utterly  unacquainted  with  that 
collection    of  properties    to   which   irritability 
necessarily  belongs.     The   muscle  which  has 
ceased  to  quiver  under  the  galvanic  wire  is, 
for  all  that  we  can  tell  to  the  contrary,  the 
same  in  composition  as  that  which  is  still  ca- 
pable of  exhibiting  the  phenomenon.     More- 
over the  action  is  observed  in  a  great  variety 
of  tissues,  both  in  individual  animals,  and  in 
the  whole  series ;  tissues  which  appear  to  have 
little  in  common  saving  a  fibrous  arrangement 
of  their  particles.   But  as  the  action  in  question 
is  stopped  by  causes  which  in  no  way  affect 
the  fibre  as  such,  it  is  plain  that  this  is  not  the 
only  requisite.     Moreover  there  are  unequi- 
vocal exhibitions  of  contractility  in  animals,  in 
which  it  is  difficult  to  imagine  that  there  can 
be  any  shortening  of  fibres;  we  allude  to  the 
Infusoria,  Rotifera,  Medusae,  &c.     Tiedemann 
makes  a  separate  species  of  this  contractility, 
under  the    designation   of  "  contractilite"    des 
animaux    gelatineux."  *      There  is  reason  to 
suspect  that  ganglionic  tissue  is  importantly 
concerned  in  the  action,  partly  because  it  is 
almost  universally  distributed  through  irritable 
substances,  and  partly  because  contraction  is 
prevented  by  causes  which  operate  upon  this 
tissue.     As  long  however  as  there  are  animals 
which  manifest  contractions,  but  in  which  no 
such  tissue  can  be  detected,  it  is  impossible  to 
consider  the  latter  an  essential  element  in  the 
action  generally ;  though  it  may  be  quite  es- 
sential in   the  animals  in  which  it  is  found  ; 
just  as  a  heart,  though  by  no  means  necessary 
to  the  function  of  circulation  in  the  abstract,  is 
indispensable  in  the  animal  of  whose  system  it 
forms  a  part. 

Irritability  may  be  destroyed  by  substances, 
either  applied  directly  to  the  part  or  acting 
upon  the  general  system.  Thus,  the  fibres  of 
the  heart  may  be  paralysed  by  a  solution  of 
opium  injected  into  its  cavities,  or  by  essential 
oil  of  tobacco  given  by  the  mouth.  Light- 
ning annihilates  the  property  all  over  the  body. 
The  motions  of  Infusoria  may  be  arrested  by  a 
shock  of  galvanism,f  by  solutions  of  opium 
and  camphor,  and  by  the  vapour  of  sulphur. 
Arsenical  preparations  have  a  similar  effect. 
The  contractions  of  capillary  vessels  in  the 
higher  animals  may  be  arrested  by  a  certain 
description  of  injuries  of  the  brain  and  spinal 
marrow.];  But  it  is  needless  to  multiply  ex- 
amples. 

*  Traite  complet  de  Physiologie  de  1'  Homme,  tra- 
duit  de  TAllemand  par  A.  J.  L.  Jourdan,  D.M.P. 
2de  partie,  p.  782. 

t  Tiedemann,  p.  617. 

J   See  Wilson  Philip  on  the  Vital  Functions. 

:;  i 


794 


DEATH. 


Such  then  are  the  causes  of  molecular  death. 
For  a  history  of  its  phenomena,  when  partial, 
we  must  refer  to  the  article  MORTIFICATION. 
Its  characters  when  universal,  that  is,  when  the 
consequence  of  systemic  death,  will  be  con- 
sidered when  we  come  to  speak  of  the  signs  of 
the  reality  of  death. 

SYSTEMIC   DEATH. 

Systemic  life  is  constituted  by  those  actions 
•which  maintain  the  mutual  dependence  of  the 
several  parts  of  the  organic  whole.  Such  are 
the  functions  which  provide  new  matter  for 
the  blood,  (digestive  secretion  and  absorp- 
tion)— that  which  effects  a  chemical  change  in 
the  blood,  (respiration) — that  which  distri- 
butes it  through  the  organs  and  tissues,  (cir- 
culation cardiac,  arterial,  capillary,  and  venous) 
• — that  which  removes  from  the  blood  effete 
matters,  (excretive  secretion) — and  that  which 
is  intimately  connected  with  all  these  functions, 
though  we  are  ignorant  of  the  mode  of  its 
operation,  viz.  the  function  of  nervous  matter 
or  innervation.  The  cessation  of  these  actions, 
and  the  consequent  solution  of  connection 
between  the  various  parts  of  the  body,  is  sys- 
temic death.  With  the  cessation  of  the  re- 
maining functions,  or  those  which  maintain 
certain  relations  between  the  organic  body 
and  objects  external  to  it,  constituting  the 
animal  life  of  Bichat,  and  the  relative  life  of 
others,  we  have  nothing  to  do  in  this  place. 
(See  SLEEP.) 

The  obstruction  of  any  one  of  the  functions 
above  enumerated  must  in  a  longer  or  shorter 
space  of  time  bring  the  others  to  a  termination. 
But,  as  the  arrest  of  the  circulation  acts  upon 
the  other  functions  immediately,  while  the 
latter  affect  one  another  merely  by  the  inter- 
vention of  the  former,  we  may  very  properly 
consider  the  causes  of  systemic  death  under 
the  general  head  of  Syncope. 

1 .  Syncope  by  asphyxia. —  We  shall  not 
stop  to  inquire  in  what  manner  the  suppres- 
sion of  respiration  arrests  the  action  of  the 
heart,  as  the  question  has  been  very  fully  and 
satisfactorily  considered  in  thearticle  ASPHYXIA. 
For  the  same  reason  we  shall  waive  the  dis- 
cussion of  the  accidental  causes  of  this  state, 
viz.  strangulation,  submersion,  &c.  &c.  The 
diseases  which  aie  said  to  produce  death  by 
asphyxia  are  those  in  which  syncope  would  not 
supervene  when  it  does,  but  for  the  obstruc- 
tion of  the  respiration.  They  are  for  the  most 
part  affections  either  of  the  respiratory  ap- 
paratus itself,  or  of  the  brain  and  spinal  mar- 
row ;  and  it  is  almost  superfluous  to  add  that 
they  prevent  the  intercourse  between  the  blood 
and  pure  air,  either  by  blocking  up  the  air- 
passages,  or  by  stopping  those  muscular  actions 
which  are  essential  to  a  change  in  the  contents 
of  the  pulmonary  tubes  and  cells.  Certain 
organic  diseases  of  the  heart  itself  are  said  to 
produce  death  by  asphyxia.  In  these  cases 
there  is  an  obstruction  to  the  motion  of  the 
blood  through  the  left  side  of  the  heart ;  and 
in  the  majority  of  them  the  asphyxial  sym- 
ptoms are  not  so  much  the  direct  effects  of  the 
impediment  in  the  heart,  as  of  the  intermediate 
pulmonary  affections,  some  of  the  most  fre- 


quent of  which  are  bronchitis,  cedema  of  the 
lung,  and  pulmonary  apoplexy.  When,  how- 
ever, a  person  dies  suddenly,  with  asphyxial 
symptoms  resulting  from  an  arrest  of  the  circu- 
lation at  the  left  side  of  the  heart,  without  any 
intervening  derangement  in  the  organs  of  re- 
spiration, the  case  ought  not  to  be  considered 
an  instance  of  genuine  asphyxia.  The  ap- 
pearances imitative  of  this  state  (we  allude 
more  particularly  to  various  phenomena  be- 
longing to  venous  congestion)  are  not  occa- 
sioned as  in  true  asphyxia  by  the  stagnation 
of  blood  in  the  extremities  of  the  pulmonary 
arteries,  the  consequence  of  its  not  being 
arterialized,  but  by  the  obstacle  presented 
to  the  currents  in  the  trunks  of  the  pul- 
monary veins  by  the  lesion  of  the  heart. 
In  brief,  the  anatomical  difference  in  the  two 
states  is,  that  in  the  one  the  pulmonary  arte- 
ries only,  in  the  other  both  these  and  the 
pulmonary  veins  are  the  seats  of  congestion  ; 
the  physiological  distinction  is,  that  in  the 
former  the  obstruction  is  chemical,  in  the  latter 
mechanical. 

2.  Syncope  by  nervous  lesions. — The  various 
parts  of  an  animal  body  are  bound  together 
by  a  reciprocity  of  action,  over  and  above  that 
particular  connection  which  exists  between 
certain  organs,  and  which  results  from  a  mu- 
tual subservience  of  function.  In  the  latter, 
the  association  is  perceptible  in  the  normal 
condition  of  the  body,  as,  for  instance,  be- 
tween the  organs  of  digestion  and  those  of 
secretion,  or  of  digestion  and  sanguifaction, 
or  in  the  sympathetic  actions  of  the  respiratory 
muscles ;  but  the  other  species  of  connection 
is  only  or  chiefly  observed  in  morbid  con- 
ditions; in  other  words,  it  is  only  when  dan- 
ger is  threatened  to  one  organ  that  the  others 
give  tokens  of  their  intimacy  and  of  their 
interest  in  its  well-being.  But  for  our  know- 
ledge of  the  existence  of  this  community  of 
feeling  (a  phrase  to  be  taken  only  in  a  me- 
taphorical sense),  it  would  be  impossible  to 
throw  any  light  upon  the  fatal  consequences 
of  a  great  number  of  diseases  and  injuries. 
There  can  be  little  doubt  that  in  all  states  of 
the  system  it  contributes  very  materially  to  the 
production  of  that  individuality  which  is  one 
of  the  grand  characteristics  of  organic  beings, 
and  which  becomes  more  and  more  obvious  as 
our  survey  rises  to  the  higher  departments  of 
the  animal  kingdom.  There  is  a  manifest  in- 
equality in  this  respect,  even  among  the  su- 
perior classes  of  animals.  Many  lesions  that 
would  be  fatal  to  birds  and  Mammalia,  are 
comparatively  trivial  to  reptiles,  not  so  much 
because  the  injured  part  is  of  less  importance 
in  the  functional  arrangements  of  the  latter, 
as  because  other  parts  have  less  sympathy 
with  it. 

There  is  no  subject  in  the  whole  range  of 
Physiology  more  beset  with  difficulties  than  the 
inquiry  into  the  causation  of  sympathy.  Vas- 
cular connection  has  been  thought  by  some  to 
explain  the  secret  sufficiently,  by  others  the 
contiguity  or  continuity  of  tissues.  Some 
have  seen  the  media  of  communication  in  the 
ganglionic  nerves,  others  in  the  nerves 


DEATH. 


f95 


respiratory.  We  cannot  enter  into  the  discus- 
sion, and  therefore  refer  to  the  article  SYM- 
PATHY. But  we  beg  to  state  that  we  have  no 
where  seen  the  subject  treated  with  more  eru- 
dition and  acuteness,  than  in  Dr.  Fletcher's 
Rudiments  of  Physiology.* 

But  while  there  can  be  no  question  that  all 
the  organs  are  more  or  less  related  in  the  man- 
ner above  indicated,  it  is  not  less  evident  that 
the  connection  between  some  is  of  a  far  more 
intimate  nature  than  between  others.  It  is 
almost  needless  to  instance  the  brain  and  the 
stomach,  the  brain,  spinal  marrow,  and  the 
heart,  the  heart  and  every  part  of  the  system, 
&c.  &LC.  By  overlooking  the  sympathetic  re- 
lation between  the  brain  and  the  heart,  Bichat 
fancied  that  when  he  had  proved  the  functional 
independence  of  the  latter  organ,  he  was  com- 
pelled to  search  in  some  third  part  for  the  link 
between  the  death  of  the  one  and  that  of  the 
othcr.-f-  It  cannot  be  denied  that  in  a  large 
proportion  of  cases,  the  syncope  which  follows 
lesions  of  the  cerebro-spinal  system,  is  not  a 
direct  consequence,  and  that  there  is  an  in- 
termediate suppression  of  the  function  of  the 
lungs, — that  in  other  words  the  syncope  is  the 
effect  of  asphyxia. J  (see  ASPHYXIA.)  It  is 
somewhat  remarkable  that  the  illustrious  phy- 
siologist just  mentioned  should  have  forgotten 
certain  pathological  facts  which  afford  con- 
vincing evidence  that  cerebral  injury  may  pro- 
duce death  without  developing  the  phenomena 
of  asphyxia;  the  "  apoplexie  foudroyante," 
for  example,  and  the  concussion  of  a  blow  or 
a  fall.  Nor  is  it  less  surprising  that  in  his 
numerous  experiments  upon  animals  he  should 
not  have  noticed  what  was  afterwards  fully 
demonstrated  by  Legallois  and  W.  Philip,  that 
both  the  heart  and  the  capillaries  may  be  imme- 
diately paralysed  by  violence  done  to  the  brain 
and  spinal  marrow.  It  must  be  remembered, 
however,  that  this  result  is  much  affected  both 
by  the  extent  and  by  the  nature  of  the  injury. 
Thus  the  brain  may  be  sliced  and  the  spinal 
cord  divided,  with  no  other  influence  upon  the 
circulation  than  that  which  depends  upon  the 
interference  with  the  respiratory  actions;  but 
laceration  or  crushing  of  the  cerebral  matter 
is  immediately  felt  by  the  heart  and  capil- 
laries. In  these  cases  the  circulation  ceases, 
not  because  the  cerebro-spinal  axis  takes  any 
part  in  that  function,  but  because  it  is  con- 
nected with  the  heart  in  the  same  manner  as 
we  have  stated  that  all  the  parts  of  the  body 
are  more  or  less  connected, —  in  bonds  of 
alliance  though  not  of  dependence.  We  have 
reason,  however,  to  believe  that  the  intimacy 
of  the  alliance  between  the  brain  and  the  heart 

*  Part  ii.  chap.  vi. 

t  Recherches  sur  la  Vie  et  la  Mort,  art.  xii.  $2. 

\  We  must  not  forget  that  even  in  many  of  these 
cases  there  is  no  immediate  communication  of 
injury  from  the  part  primarily  aftected  to  the  organs 
of  respiration.  Thus,  when  a  slight  hemorrhage 
in  one  of  the  hemispheres  of  the  brain  occasions 
asphyxia,  we  are  bound  to  believe  that  there  is  in 
the  first  place  a  sympathetic  communication  of  de- 
rangement to  the  medulla  oblongata,  unless  the 
hemorrhage  has  been  so  considerable  as  to  cause 
compression  of  the  whole  encephalic  mass. 


is  scarcely  equalled  by  that  of  any  otlu  i 
in  the  system. 

The  anatomical  eh meters  of  syncope  by 
nervous  lesion  are  detennineil  by  the  modus 
Operand!  of  the  injury.  If  the  latter  UTCMtt 
the  action  of  the  heart  only  by  obstruct  in-  1 1n- 
respiratory  movements,  the  appearances  are 
those  of  asphyxia,  (see  ASPHYXIA.)  But  it 
the  operation  be  immediately  upon  the  heart, 
there  will  be  a  difference  in  the  appear- 
ances,—  a  difference  which  likewise  be- 
longs to  all  cases  in  which  the  circulation 
ceases  without  previous  obstruction  of  respi- 
ration. The  blood,  instead  of  being  accumu- 
lated in  the  right  cavities  of  the  heart,  and  in 
the  pulmonary  arteries,  is  more  equally  dis- 
tributed between  these  and  the  left  cavities, 
and  the  pulmonary  veins.  There  is  generally 
a  perceptible  difference  in  the  colour  of  the 
blood  in  the  two  sides  of  the  heart,  but  some- 
what less  than  might  at  first  be  expected.  The 
defect  of  arterial  tint  in  the  coagula  of  the 
left  side  may  be  fairly  attributed  to  the  drain- 
ing away  of  the  serum,  and  consequently 
with  it  of  the  saline  particles  upon  the  pre- 
sence of  which  the  red  colour  depends.  Blood 
is  found  in  the  aorta  and  in  many  of  the  ar- 
teries. The  signs  produced  by  venous  con- 
gestion, such  as  engorgement  of  the  liver  and 
spleen,  turgescence  of  the  cerebral  veins  and 
of  those  of  the  mucous  membranes,  are  want- 
ing, as  well  as  the  tumefaction  of  the  face, 
the  puffing  of  the  lips,  the  projection  of  the 
eyes,  and  the  deep  lividities  characteristic  of 
that  condition.  We  must  remember  that  the 
appearances  are  considerably  modified  if  syn- 
cope has  taken  place  gradually.  In  such  in- 
stances the  heart  is  generally  found  empty. 
The  cause  of  this  condition  is  obvious.  In 
the  first  place,  as  the  degree  of  the  diastole 
must  be  proportionate  to  the  systole,  it  is 
obvious  that  when  the  latter  is  enfeebled,  less 
blood  will  be  received  into  the  cavities;  and, 
secondly,  as  less  blood  is  driven  into  the  pul- 
monary artery  and  the  aorta,  there  will  be  less 
to  return  in  a  given  space  of  time,  and  con- 
sequently there  will  be  less  impetus  in  the 
returning  currents.  It  is  easy  to  perceive  that 
before  the  final  and  feeblest  contraction,  which 
must  be  succeeded  by  a  correspondency  slight 
dilatation,  the  current  of  blood  pressing  for 
admission  must  be  very  trifling. 

3.  Syncope  by  injuries  of  the  heart  itself. — 
This  is  of  too   obvious  a  nature  to    require 
comment. 

4.  Syncope  by  injuries  of  other  organs  and 
tissues. — When  death  follows  quickly  upon  a 
lesion  which  does  not  necessarily  implicate  the 
vital  organs,  properly  so  called,  we  say  in  ge- 
neral terms  that  a  shock  has  been  given  to  the 
nervous  system,  in  consequence  of  the  strong 
probability  that  some  portion  of  this  system  is 
the  agent  of  sympathy.     If  violent  pain   at- 
tends   the  injury,    and  to  this  succeeds  loss 
of  consciousness,   and   then  cessation   of  the 
heart's  action,  it  is  fair  to  infer  that  the  brain 
was  first  operated  upon  through  the  nerves  of 
sensation,   and  that  the  derangement  of  this 
oitran  affected  the  circulation.     But  there  are 

3r  2 


796 


DEATH. 


eases  of  injury  in  which  syncope  occurs  with- 
out any  antecedence  of  pain  or  of  leipothymia, 
and  in  which  there  is  no  reason  for  supposing 
any  cerebral  affection  in  the  chain  of  events. 
Of  this  kind  are  extensive  mechanical  injuries 
of  the  extremities,  burns,  rupture  or  over-dis- 
tenlion  of  the  stomach,  &c.  Whether  the 
nerves  which  convey  the  morbid  impression 
belong  to  the  ganghonic  or  to  the  respiratory 
class,  we  do  net  profess  to  decide.  The  im- 
mediately fatal  eHect  of  a  blow  upon  the  epi- 
gastrium or  of  a  draught  of  cold  water  when  the 
body  is  heated,  has  been  attributed  by  some 
to  a  shock  given  to  the  semilunar  ganglion, 
and  the  communication  of  the  impression  to 
the  heart ;  while  others  are  of  opinion  that  the 
injury  is  fatal  by  "  paralysing  the  whole  res- 
piratory set  of  nerves  from  the  violent  shock 
com  municated  to  the  phrenic,  and  thus  shut- 
ting up  as  it  were  the  fountain  of  all  the 
sympathetic  actions  of  the  body."*  "  A  blow 
on  the  pit  of  the  stomach,"  says  Sir  Charles 
Bell,  "  doubles  up  the  bruiser  and  occasions 
the  gasping  and  crowing,  which  sufficiently 
indicate  the  course  of  the  injury — a  little  more 
severe,  and  the  blow  is  fatal.  A  man  broken 
on  the  wheel  suffers  dreadful  blows,  and  his 
bones  are  broken,  but  life  endures — the  coup- 
de-grace  is  a  blow  on  the  stomach." 

5.  Syncope   by  mental  emotion. — Instances 
of  this  occurrence  must  be  familiar   to  every 
one  both  by  reading  and  by  observation.     In 
some   of   them   the    cause    in    question    has 
operated  either  by  aggravating  some  pre-exist- 
ing malady,  or  by   calling   into  action  some 
strong  predisposition  to  disease ;  as  in  struc- 
tural lesions  of  the  heart  on  the  one  hand,  and 
in  the  apoplectic  diathesis  on  the  other.    But 
in  other  instances  the  mere  violence  of  a  pas- 
sion has  at  once  extinguished  its  subject  with- 
out the  intervention   of  morbid  tendency  or  of 
actual   disease.      Such   cases    belong   to    the 
Nervous  Apoplexy  of  some  authors ;  and  cer- 
tain it  is  that  they  present  a  complete  annihi- 
lation of  sense  and  motion,  but  this  condition 
is  only  simultaneous  with,  or  immediately  suc- 
ceeded by  the  failure  of  the  circulation.     We 
have  no  doubt  that  the  change  in  the  organ  of 
the  mind,  corresponding  to  the  emotion,  ope- 
rates upon   other  parts   of  the   cerebro-spinal 
axis,  which  in  their  turn  affect  the  heart  in  the 
same  manner  as  other  preternatural   states  of 
that  system.     We  are  not  acquainted  with  arty 
example  in  which  either  high  intellectual  ex- 
citement unaccompanied  by  vehemence  of  pas- 
sion, or  mere  intensity  of  external  sensation, 
has  been  the  cause  of  sudden  death  ;  nor  could 
it  be  expected  a   priori,  since  in  the  normal 
condition  of  the  economy  there  is  by  no  means 
the  same  degree  of  connection   between  the 
action  of  the  heart  and   intellectual  and  sen- 
sific  conditions,  as  between  the  former  and  the 
emotions  and  affections. 

6.  Syncope  by  h/rmorrhage. — The  functions 
of  the  brain  are  in  man  so  dependent  upon  a 
regular  supply  of  blood  to  the   organ,  that  a 
sudden  diminution  of  it  is  alone  sufficient  to 

*  Dr.    Fletcher,  op.  cit.   part  ii.  chap.  6.  p.  60. 


occasion   vertigo   and    unconsciousness ;    and 
this  occurrence  often    takes   place   when   the 
action  of  the  heart  itself  is  little  or  not  at  all 
affected.     Every  one  is  acquainted   with    the 
effect  of  a  change  in  the  relative  quantity  of  the 
blood  in  the  cerebral  vessels,  determined  by 
suddenly  rising  from   the  recumbent  posture. 
Now  it  has  been  often  observed  that  vertigo  in- 
duced by  other  causes  has  been  followed  by 
suspension  of  the  circulation  ;  that  is  to  say, 
the  state  of  the  brain,  which  was  attended  by 
giddiness,  arrested   the   motions  of  the  heart. 
It  has  therefore  been  inferred  that  loss  of  blood 
operates  indirectly  upon   the  heart  through  the 
affection  of  the  brain.     When  two  phenomena 
follow  each  other  in  such  quick  succession  as 
to  be  all  but  simultaneous,  it  is  difficult  to 
determine  which  is  cause  and  which  is  effect, 
or  whether  they  may  not  be  the  common  ef- 
fects of    some    other    event.      Certain    facts 
would  seem  to  indicate  that  the  latter  is  the 
true  interpretation  of  the   phenomena  which 
we  are  considering.     Thus  haernorhage  some- 
times affects  the  nervous  system  in  the  manner 
alluded  to,  without  presenting  any  check   to 
the  contractions  of  the  heart ;  not  to  mention 
that  it  appears  more  consistent  with  analogy  to 
conclude  that  the  heart  must  be  more  directly 
influenced  by   the  loss  of   that  which   is   its 
natural    stimulus,    than    by    a    change    in   a 
remote    organ.       Again,    there   are    cases   in 
which  haemorrhage  makes  a  decided  impres- 
sion upon  the  organs  of  circulation  before  the 
brain  has  given  signs  of  any  material  derange- 
ment of  its   functions;  but  in  these  the  loss 
of  blood   is  more  gradual  than  in  the  former 
instances.     "  When  haemorrhage  is  very  gra- 
dual," says  Dr.   Alison,  "  all  the  indications 
of  failure  of  the  circulation  may  come  on — the 
feebleness  of  muscular  action, — the  paleness 
and  collapse  of  the  countenance, — the  cold- 
ness beginning  at   the  extremities, — the  cold 
sweat  beginning   on  the  face, — and  the  pulse 
may     become     imperceptible ;     without    the 
senses  or  the  intellect  being  impaired,  and  a 
slightly  laborious  or  heaving  respiration  may 
be  almost  the  only  indication  of  injury  of  the 
nervous  system  up  to  the  moment  of  death."* 
From  facts  of  this  description  we   should  be 
willing  to  decide  at  once  that  it  is  a  superfluous 
multiplication  of  causes  to  attribute  the  stop- 
page of  the  circulation  in  any  case  of  haemor- 
rhage to  the  influence  of  cerebral  changes,  when 
the  direct  operation  of  the  cause  upon  the  heart 
itself  is  adequate  to   the  explanation ; — were 
it  not  for  the  important  fact  that  haemorrhage 
alone  often  fails  to  produce  syncope  till  some 
circumstance  has  intervened,  the  operation  of 
which  is  manifestly  upon  the  nervous  system. 
Thus  nothing  is  more  common  in  bloodletting 
than  to  find  the  heart  unaffected  by  the  with- 
drawal of  a  considerable  quantity  of  its  stimu- 
lus, so  long  as  the    posture  of  the   body    is 
horizontal ;  but  on  raising  the  head,  a  change 
which  for  obvious    reasons  renders  the  brain 


*  Outlines  of  Ph\  siology  and  Pathology,  p.  344. 
This  work  contains  a  most  valuable  chapter  upon 
the  causes  of  sudden  death. 


DEATH. 


more  sensible  of  the  loss  of  blood,  the  nervous 
symptoms,  viz.  vertigo  and  leipothymia,  ap- 
pear, and  immediately  afterwards  the  pulse 
falls  and  becomes  imperceptible.  In  corro- 
boration  of  this  fact  we  might  at  first  be 
inclined  to  mention  that  a  diminution  of  the 
quantity  of  the  blood,  so  far  from  depressing 
the  circulation,  often  appears  to  excite  it 
violently,  as  in  what  has  been  denominated 
hamorrhagic  reaction;  but  in  such  instances 
analogous  effects  have  been  also  witnessed  in 
the  cerebral  functions,  namely,  delirium  and 
extreme  sensibility,  &c.  On  the  whole  we 
may  conclude  with  regard  to  both  these  sys- 
tems that  the  depressing  effect  of  haemorrhage 
depends  rather  upon  the  suddenness  of  the 
change,  than  upon  the  absolute  diminution 
of  the  quantity  of  the  fluid. 

7.  Syncope  by  poisons. — Some  substances 
depress  the  action  of  the  heart  in  the  man- 
ner to  which  we  had  occasion  to  refer  when 
speaking  of  syncope  by  mechanical  injuries  of 
the  tissues  generally.  Of  this  kind  are  the 
mineral  acids,  oxalic  acid,  and  the  pure 
alkalies.  They  produce  death,  when  taken 
in  certain  quantities,  by  means  of  that  de- 
pression of  the  circulation  which  follows 
the  destruction  of  the  parts  to  which  they 
are  applied.  In  smaller  quantities  they  may 
be  more  remotely  fatal  by  exciting  disease, 
gaslro-enteritis  for  instance.  One  of  the  sub- 
stances mentioned,  viz.  oxalic  acid,  may  in- 
duce direct  depression  of  the  circulation,  un- 
attended by  cerebral  aifection,  even  when  its 
chemical  effect  upon  the  stomach  is  prevented 
by  dilution.  In  this  form  it  must  be  classed 
with  a  lar^e  collection  of  substances  which  in 
certain  doses  subdue  the  moving  powers  of 
the  circulation,  without  any  previous  coma, 
without  any  alteration  of  the  tissues,  and 
without  any  gastric  irritation;  such  are  arse- 
nic in  large  quantities,  tobacco,  digitalis,  and 
most  of  the  animal  poisons.  To  the  same 
class  belong  those  malarious  and  contagious 
poisons  which  occasionally  induce  fatal  syn- 
cope before  any  of  their  ordinary  effects  upon 
the  general  functions ;  we  scarcely  need  to 
mention  cholera,  malignant  typhus,  plague, 
scarlatina,  £c.  The  narcotic  substances  mani- 
festly act  first  upon  the  cerebro-spinal  system  ; 
syncope  follows  either  with  or  without  as- 
phyxia. Those  which  act  rapidly  appear  to 
strike  the  circulation  before  asphyxia  has  had 
time  to  transpire ;  we  may  instance  hydro- 
cyanic acid,  essential  oil  of  almonds,  large 
doses  of  opium  and  of  alcohol,  certain  gases, 
particularly  sulphurtted  hydrogen  and  cyanoger. 

8.  Syncope  by    cold    and    lightning. — It   is 
not  clear  whether  these  outward  agents  arrest 
the   circulation   through   their  influence  upon 
the  nervous   system,  or  by  directly  paralysing 
the  irritablity  of  the  fibres  of  the  heart. 

9.  Syncope  by  inanition. — In  cases  of  this 
description  it  is' probable  that  the  failure  of  the 
heart's   action  is   a   compound  result  of   the 
prostration  of  the  nervous  system,  and  of  the 
diminution   of    the    proper    stimulus    of   the 
circulation. 

10.  Syncope  by  disease.— All  fatal  maladies 


must  terminate  in  cessation  of  the  heart'sa  c- 
tion,  but  we  limit  the  present  category  to  those 
cases  in  which  this  event   is  unpreceded  by 
asphyxia.      The    others  have    been  hinted  at 
under  the  head  of  syncope  by  asphyxia.     The 
diseases   now   under    consideration    may,    \\e 
think,  be  conveniently  arranged  as  follows: — 
1.  Those  which  stop  the  motion  of  the  In-art 
by  obstructing  its  mechanism,  e.  g.  collection^ 
of  fluid  in  the  pericardium,  lesions  of  the  val- 
vular apparatus  ;  accumulation  of  fat,  &c. ;  or 
by  diminishing  the  contractility  of  the  fibres, 
e.g.  atrophy,  or  degeneration  of  the  muscular 
substance;*   or  by   perturbing  in  some  unex- 
plained manner  the  nervous  influence,  e.  g-  the 
functional  form  of  angina  pectoris.     2.  Those 
which   are    attended   with   ha-morrhage,   e.  g. 
aneurisms,  and  diseases  of  mucous  surfaces. 
3.  Those  which  induce  excessive  and  long-con- 
tinued discharges.  Thus  fatal  syncope  has  sud- 
denly terminated  a  fit  of  diarrhoea ;  but  it  must  be 
borne  in  mind  that  in  such  instances  the  po\\«-r 
of  the  circulation  had  previously  been  greatly 
enfeebled  either  by  deterioration  of  the  blood, 
or  by  causes  acting  on  the  innervation  of  the 
heart,  or  by  the  existence  of  irritation  in  some 
part  of  the  system.     4.  Disease.*  implicating 
the  cerebro-spinal  organs.     Some  of  these  ope- 
rate in   the  same  manner  as  those  accidental 
injuries  which  produce  concussion,  and  which 
have  been  already  adverted  to.     Thus  in  that 
species  of  apoplexy  which  terminates  instan- 
taneously,   (tipoplexie.  foudroyanfe  of  French 
authors.)  the  sanguineous  extravasation  appears 
to  have  the  same  effect  as  a  mechanical  shock 
to  the  whole  nervous  mass.  The  more  common 
form  of  apoplexy  extinguishes  life  by  impeding 
the  respiratory  movements.     We   have   more 
than  once  known  cases  of  structural  disease  of 
the  brain    terminate   by  sudden  syncope,  but 
have   learned   nothing  from    the    necroscopy 
capable  of  explaining  why  the  fata!  occurrence 
took  place  at  the  precise  time  when  it  did, 
rather  than  at  any  other  moment  in  the  period 
during  which  the  disease  had  existed ;  though 
it  was  easy  to  conceive  that  a  lesion  of  this 
description  must  have  been  competent  at  any 
time  to   produce  such    changes    in   the  cere- 
bral   circulation    as  would  induce  the  result 
in  question.     5.  Diseases  attended  with  what 
has  been  vaguely  called  irritation,  either  short 
and  intense,  or  moderate  but  long-continued. 
This   irritation   consists  sometimes  of  inflam- 
mation and  its  sequelae,  and  sometimes  of  spe- 
cific structural  alterations.    A  good  illustration 
of  the  former  of  these  is  afforded  by  peritonitis, 
which  frequently  cuts  off  the  patient  by  sub- 
duing the  action  of  the  heart,  long  before  this 
effect  could  transpire  from  derangements  of  the 
organs  contiguous  to  the  seat  of  disease.     Still 
more  remarkable  in  this  point  of  view  are  the 
effects   of  acute   inflammation   of  a   synovial 
capsule.     It  is  true  that  these  affections  are 
accompanied  by  violent  pain,  which  mi  Jit  he 
said   in    common    language  to    exhaust    the 
powers  of  the  system,  or  in  stricter  phrase,  to 

*  See  Mr.  Chevalier's  interesting  cases  of  sudden 
death  in  the  Mecl.  Ch.  Trans,  vol.  i. 


703 


DEATH. 


produce  a  change  in  the  nervous  system  in- 
compatible with  the  continuance  of  the  action 
of  the  heart ;  but  mere  pain  will  not  account 
for  the  fact  in  question,  since  in  other  diseases 
it  attains  a  more  intense  degree,  and  lasts 
longer,  as  in  neuralgia,  without  inducing  fatal 
consequences.  The  causation  is  probably 
analogous  to  that  of  syncope  from  mechanical 
injuries  of  tissues,  to  which  we  have  already 
devoted  some  remarks.  But  why  an  inflam- 
matory condition  of  serous  membranes  should 
exert  a  more  depressing  influence  upon  the 
circulation  than  that  of  many  other  tissues  that 
might  be  named,  is  a  subject  wrapped  in  deep 
obscurity ;  yet  it  is  scarcely  darker  than  the 
question,  why  such  changes  should  in  the  first 
instance  excite  and  perturb  the  heart,  or  why  a 
similar  excitement  should  ensue  upon  the  soft- 
ening of  a  cluster  of  tubercles,  and  to  a  degree 
inexplicable  by  the  functional  derangement 
of  the  part  in  which  the  tubercles  exist.  Dis- 
eases in  which  the  powers  of  the  system  are 
said  to  be  worn  out,  are  in  reality  such  as  have 
gradually  enfeebled  the  action  of  the  heart, 
partly  perhaps  through  the  intervention  of 
changes  affecting  the  blood,  the  respiration  and 
the  nervous  system,  but  probably  in  a  great 
measure  by  as  direct  a  relation  between  the 
diseased  part  and  the  change  in  the  circulation, 
as  between  violent  lesions  of  tissue  and  syn- 
cope. Under  the  present  head  are  included 
a  host  of  chronic  maladies.  6.  Diseases 
caused  by  vitiation  of  the  blood.  Such  are 
scorbutus,  certain  forms  of  marasmus,  the 
cachexiae  revealed  by  dropsies,  and  certain 
fevers  of  a  malignant  character.  We  might 
also  mention  those  depravations  indicated  by 
morbid  secretions,  such  as  tubercle,  carcinoma, 
melanosis,  &c.  but  that  the  solids  are  so  much 
involved  in  these  diseases,  that  it  becomes 
difficult  to  determine  whether  the  heart's  action 
was  weakened  by  the  primary  lesion  of  the 
blood,  or  by  the  secondary  one  of  the  tissues. 
7.  Diseases  which  produce  vitiation  of  the 
blood.  Such  are  that  large  class  in  which 
there  is  disorder  of  the  chylopoietic  processes, 
and  that  smaller  group  in  which  the  convey- 
ance of  the  chyle  is  impeded.  Derangements 
of  the  secernent  and  excernent  organs  must  be 
arranged  in  this  division,  and  particularly 
those  of  the  liver,  the  skin,  and  the  urinary 
apparatus.  Diabetes  is  a  state  of  the  system 
in  which  the  blood  is  probably  deteriorated 
both  by  defective  assimilation,  and  by  faulty 
excretion.  Upon  the  whole  of  this  class  of 
diseases  it  must  be  remarked  that  we  seldom 
or  never  have  opportunities  of  witnessing  their 
uncombined  influence  in  depressing  the  organs 
of  circulation. 

11.  Syncope  by  old  age. — We  have,  in  a  for- 
mer article  (AGE)  endeavoured  to  trace  the 
principal  events  in  senile  decay.  The  death 
which  follows  this  gradual  decline  of  the  func- 
tions, presents  the  strongest  possible  contrast 
to  that  of  sudden  syncope.  Jn  the  latter  in- 
stance the  assault  is  mad#  u^or*  the  very  citadel 
of  lite,  the  conquest  of  which  secures  an  im- 
mediate surrender  of  the  minor  bulwarks  and 
dependencies ;  but  in  the  former  the  fortress  is 


reduced  only  after  a  long  series  of  defections  in 
the  outworks,  and  a  consequent  loss  of  supplies, 
or,  to  quote  the  words  of  an  illustrious  author, 
"Void  done  la  grande  difference  qui  dis- 
tingue la  mort  de  vieillesse,  d'avec  celle  qui 
est  1'effet  d'un  coup  subit ;  c'est  que  dans  1'une, 
la  vie  commence  a  s'eteindre  dans  Unites  les 
parties,  et  cesse  ensuite  dans  le  coeur;  la  mort 
exerce  son  empire  de  la  circonfe'rence  au 
centre.  Dans  1'autre,  la  vie  s'e"teint  dans  le 
co2ur,  et  ensuite  dans  toutes  les  parties ;  c'est 
du  centre  a  la  circonfcrence  que  la  mort  en- 
chaine  ses  phenomenes."* 

SIGNS    OF    APPROACHING    DEATH. 

It  would  be  tedious  and  altogether  beyond 
the  compass  of  this  work  to  enumerate  all  the 
phenomena  presented  by  the  dying  system, 
since  they  vary  with  the  cause  of  death.  We 
shall  aim  rather  at  describing  and  accounting 
for  those  which  are  common  to  most  diseases 
and  to  natural  decay;  reserving  to  ourselves 
the  liberty  of  noticing  here  and  there  some  of 
the  more  striking  varieties. 

We  might  rationally  expect  that  the  first 
indications  of  dissolution  would  appear  in  the 
relative  functions ;  hebetude  of  the  senses,  in- 
action of  the  muscles,  vacancy  of  the  intellect, 
extinction  of  the  sentiments;  and  such  is,  in 
fact,  the  course  of  events  in  natural  death. 
We  have  known  the  aged  man  remain  feeling- 
less,  motionless,  mindless,  for  many  days  be- 
fore the  cessation  of  the  organic  functions. 
This  kind  of  death  is  sometimes  imitated  by 
apoplexy;  but  in  the  former  the  destruction  of 
the  animal  life  does  not,  as  in  the  latter,  arise 
from  a  lesion  of  the  brain ;  its  organs  appear  to 
undergo  a  gradual  process  of  enfeeblement.  In 
many  febrile  maladies  there  is  the  same  priority 
of  failure  on  the  part  of  the  cerebral  functions, 
but  they  are  generally  preceded  by  more  or  less 
actual  disease  of  the  organ.  But  in  the  termi- 
nation of  some  disorders  the  functions  alluded 
to  continue  to  the  very  last,  almost  surviving 
the  circulation  itself.  It  will  be  found  however 
that  the  seat  of  such  disorders  was  remote  from 
the  encephalon,that  it  did  not  communicate  with 
the  latter  by  any  special  sympathy,  and  that 
the  extinction  of  the  cerebral  functions  was  at- 
tributable to  the  arrest  of  circulation  in  that 
organ,  in  common  with  many  others.  The 
cases  in  which  the  mind  is  said  to  continue 
clear  and  vigorous  amid  the  ruin  of  the  body, 
will  be  found  to  agree  in  the  fact  that  the 
organ  is  correspondently  unimpaired ;  they  are 
for  the  most  part  chronic  diseases  of  the  thorax, 
abdomen,  pelvis,  and  extremities.  Certain 
affections  even  of  the  cerebro-spinal  system 
may  not  interfere  with  the  understanding  and 
feelings  until  almost  the  last  moments;  but 
they  are  such  as  do  not  involve  those  divisions 
with  which  thought  is  believed  to  be  more 
immediately  connected :  we  may  instance 
tetanus.  But  although  in  these  maladies  we 
do  occasionally  observe  considerable  intellec- 
tual soundness  till  within  a  very  short  period 
of  death,  we  have  far  more  commonly  been 
able  to  detect  some  degree  of  delirium,  an 

*  Bichat,  Eech.  sur  la  Vic  et  la  M-ort,  p.  151. 


DEATH. 


799 


exaltation  of  one  part  of  the  menial  constitution 
at  the  expense  of  the  others.  Kxeitemeiit  of 
the  imagination  has,  we  doubt  not,  been  fre- 
quently mistaken  for  general  mental  vigour. 
\\eshoulclplace  such  instances,  however,  far 
below  those  in  which  there  remains  sufficient 
steadiness  of  the  understanding  to  direct  the 
provisions  of  a  will  ;  though  by  many  observers 
such  a  condition  of  the  intellect  would  be  con- 
sidered a  far  slighter  evidence  of  the  triumphs 
of  mind  over  matter,  than  the  impassioned 
expressions  to  which  the  dying  man  sometimes 
gives  utterance,  when  describing  the  visions  of 
his  phantasy. 

The  delirium  of  the  dying  is  often  of  a  most 
interesting  character,  and  resembles  dreaming 
more  than  any  other  form  of  derangement  that 
has  fallen  under  our  notice.  The  ideas  are 
derived  less  from  present  perceptions  than  in 
insanity,  and  yet  are  more  suggested  by  ex- 
ternal circumstances  than  in  the  delirum  of 
fever  and  phrenilis.  Thus  the  sight  of  a  by- 
stander often  suggests  the  image  of  a  friend 
long  departed,  in  which  character  the  mori- 
bund man  addresses  him,  and  talks  earnestly 
of  persons,  scenes,  and  events  belonging  to  a 
former  period  of  his  history  as  if  still  present. 
The  vivified  conceptions  are  generally  derived 
from  subjects  which  either  in  his  speculative 
pursuits,  or  in  the  business  of  life,  have  princi- 
pally occupied  his  thoughts.  The  last  words 
of  Dr.  Armstrong  were  addressed  to  an  ima- 
ginary patient  upon  whom  he  was  impressing 
the  necessity  of  attention  to  the  state  of  the 
digestive  organs.  We  have  heard  that  a  great 
legal  officer  not  long  deceased,  having  raised 
himself  for  a  moment  from  his  couch,  said 
with  his  wonted  dignity,  "  Gentlemen  of  the 
jury,  you  will  find,"—  and  then  fell  back  on  his 
pillow  and  expired.  The  visual  conceptions 
reproduced  in  some  minds  often  appear  to  have 
been  derived  from  poetical  reading.  We  re- 
member hearing  a  young  man,  who  had  been 
but  little  conversant  with  any  but  civic  scenes, 
discourse  most  eloquently  a  short  time  before 
death,  of  "  sylvan  glen  and  bosky  dell,"  pur- 
ling streams,  and  happy  valleys  ;  "  babbling  of 
green  fields,"  as  if  his  spirit  had  been  already 
recreating  itself  in  the  gardens  of  Elysium. 
It  not  unfrequently  happens  that  the  spectra 
owe  their  origin  to  contemplations  of  future 
existence  ;  and  consequently  that  the  good  man's 
last  hours  are  cheered  with  beatific  visions 
and  communion  with  heavenly  visitors. 

"  Saw  yc  not  even  now  a  blessed  troop 
Invite  me  to  a  banquet,  whose  bright  faces 
Cast  thousand  beams  upon  me,  like  the  sun? 

|    They  promised  me  eternal  happiness, 

And  brought  me  garlands,  Griffith,  which  I  feel 
I  am  not  worthy  yet  to  bear  :  I  shall  assuredly." 
Henry  VIII.  Act  iv.  Sc.  2. 


Dreadfully  contrasted  with  such  visions  are 
those  which  haunt  the  dying  fancies  of  others. 
The  previous  habits  and  conduct  of  the  indi- 
vidual have  sometimes  been  such  as  to  incline 
spectators  to  enquire  whether  in  the  mode  of 
his  departure  from  existence  he  might  not 
already  be  receiving  retribution;  just  as,  in 


oilier  casc>,  celestial  dieaius  ;m,|  ,  oil,-  qim-s 
have  seemed  littmn  rewards  for  blamele-  li\,  - 
and  religious  meditation.  It  would  be  piv 
sumptuous,  however,  to  lia/.ud  much  upon  the 
final  causes  of  the  various  modes  of  termina- 
ting the  career  of  life,  not  only  for  ri-rta.n 
obvious  general  reasons,  but  also  because  we 
have  known  both  the  virtuous  and  the  vicious 
pass  away  in  states  of  unconsciousness,  to  all 
appearance  precisely  similar. 

One  of  the  most  curious  instances  of  de- 
rangement that  we  have  met  with  occurn d  in 
a  phthisical  patient.  It  consisted  in  a  morbid 
association  of  ideas  by  mere  similarity  of  ver- 
bal sound,  or  in  other  words  a  propensity  to 
rhyme.  Every  person  who  tame  to  the  bed- 
side was  sure  to  receive  a  distich  in  honor  of 
his  name;  nor  could  any  remark  be  made  in 
his  presence  without  his  seizing  one  of  the 
words  littered  and  finding  a  rhyme  for  it,  in 
doing  which  he  exhibited  great  ingenuity. 
We  were  unable  to  ascertain  whether  he  had 
been  addicted  when  in  health  to  attempts  at 
metre.  Recitations  of  poetry,  appearing  to  recur 
from  a  passive  process  of  memory,  with  perfect 
unconsciousness  of  what  is  passing  around, 
are  frequent  occurrences ;  and  the  passages 
selected  have  often  a  singular  coincidence  with 
events  in  the  life  of  the  moribund  rehearser. 
Sir  W.  Scott's  touching  picture  of  the  death 
of  Madge  Wildfire  has  had  many  unfie- 
litious  counteq)arts. 

Dementia  or  imbecility  sometimes  comes  on 
a  short  time  before  death*  It  is  for  the  most 
part  manifested  by  an  incapacity  of  concen- 
trating the  ideas  upon  any  one  subject,  and  by 
an  all  but  total  failure  of  memory.  The  study 
of  the  degree  of  this  condition  necessary  for 
invalidating  a  legal  document  is  of  great  im- 
portance to  the  medical  jurist.  The  mental 
weakness  is  in  no  respect  so  painfully  exhi- 
bited as  in  the  facility  with  which  the  subject 
of  it  derives  pleasure  from  puerile  amuse- 
ments. "  Playing  with  flowers  "  is  a  token  of 
approaching  dissolution  ennmerated  by  a  dra- 
matic author,  one  whose  observation  pervaded 
human  nature  in  all  its  phases.  We  remember 
visiting  a  lady  in  the  last  stage  of  a  uri- 
nary disorder,  during  the  progress  of  which 
she  had  evinced  both  strength  of  mind  and  re- 
finement of  taste  :— we  found  her  arranging 
with  great  care,  and  with  demonstrations  of 
delight  at  her  success,  a  garland  of  flowers 
around  a  chamber  utensil.  A  more  humilia- 
ting spectacle  could  scarcely  be  witnessed. 
We  augured  that  her  decease  was  near  ut  hand, 
and  she  died  on  the  following  day. 

In  the  delirium  under  consideration,  repro- 
ductions of  visual  sensations  bear  a  considera- 
ble part ;  but  in  some  cases  the  consciousness 
is  exclusively  occupied  by  them ; — they  are 
mere  ocular  spectra.  Thus  with  a  vacant  coun- 
tenance, half-shut  eyes,  and  gaping  mouth, 
and  in  a  state  of  insensibility  which  no  out- 
ward impression  can  rouse,  the  victim  of  ty- 
phus is  seen  catching  at  something  in  the  air. 
By  the  adjustment  of  the  linger  and  thumb, 
it  is  evident  that  the  imaginary  objftfe  air- 
often  minute;  audit  is  not  unlikely  tli.it  they 


800 


DEATH. 


produce  a  kind  of  annoyance  like  that  of 
muscce  volit  antes,  which  the  hand  is  instinc- 
tively attempting  to  remove.  Whether  the 
production  of  such  spectra  depends  upon 
changes  in  the  retina,  or  upon  changes  in  the 
cerebral  extremity  of  the  optic  nerve,  is  not 
altogether  certain  ;  but  we  incline  to  the  lat- 
ter view,  principally  because  other  sensations 
are  often  revived  though  the  nerves  in  which 
they  originated  have  been  paralysed  or  removed. 

Renewals  of  perceptions  of  hearing  are  not 
uncommon.  Such  are  imaginary  voices,  and 
sounds  of  tolling  bells,  &c. 

No  reason  has  been  assigned  for  that  sym- 
ptom noted  by  the  earliest  observers  —  "  pick- 
ing of  the  bed-clothes  ;  "  or,  in  Dame  Quickly's 
phraseology,  "  fumbling  with  the  sheets."  But 
we  think  it  may  be  readily  accounted  for  as 
resulting  from  revivals  of  tactual  sensations, 
which  produce  corresponding  movements,  so 
that  the  fingers  grasp  the  bed-clothes  in  mis- 
take for  the  imaginary  substance.  Something 
analogous  to  this  is  witnessed  in  delirium 
tremens,  a  disease  in  which  visual  conceptions 
are  particularly  liable  to  vivifaction  in  the 
form  of  animals,  and  in  which  also  we  have 
witnessed  the  patient  picking  the  ends  of  his 
fingers  as  if  to  remove  something  disagreeably 
adherent. 

Whether  consciousness  of  bodily  sensations 
continues  till  the  very  commencement  of  the 
death-struggle,  or  agony  ,*  as  it  is  termed,  is 
an  enquiry  often  put  to  the  medical  attendant 
either  by  patients  themselves,  or  by  their  anx- 
ious relatives.  The  ideas  entertained  by  per- 
sons unaccustomed  to  physiological  study  re- 
specting the  pains  of  dying,  have  arisen  partly 
from  their  theoretical  views  of  the  nature  of 
the  event  itself,  and  partly  from  their  obser- 
vation of  its  preceding  or  accompanying  phe- 
nomena. When  they  imagined  death  to  be  a 
kind  of  forcible  severing  of  the  spirit  from  the 
body,  —  a  separation  so  opposed  to  the  incli- 
nation of  the  former  that  some  have  fancied  it 
longing  to  return  to  the  body, 

--  "  iterumque  ad  tarda  reverti 
Corpora,  quae  lucis  miseris  tarn  dira  cupido  :  " 

or  like  the  shade  of  Hector, 


x.oii  v@yv. 
Iliad.  XXII.  362. 


EJC  ptwv  <7rra.iJi.svv) 
"On  TTorfjiov  yooua-ct, 


or  when  they  regarded  the  throes  of  death 
as  efforts  of  the  confined  inmate  to  escape 
from  its  tenement  ;  or  when  laying  aside 
their  imaginings,  they  witnessed  a  heaving 
respiration,  cold  dew  on  the  face,  and 
convulsive  agitations  of  the  whole  frame, 
affections  so  often  known  to  accompany  in- 
tense bodily  suffering,  —  it  is  not  wonderful 
that  the  process  of  dying  should  have  been 
considered  one  of  distress  and  anguish.  But 
the  practitioner  ought  to  be  able  to  console 

*  The  reader  will  scarcely  need  to  be  reminded 
that  this  word  is  used  in  its  etymological  sense, 
eiyxv,  certamen. 


the  friends  of  the  dying  by  the  assurance  that 
whatever  may  have  been  the  previous  torture, 
it  must  be  all  over  when  once  those  changes 
begin  in  which  death  essentially  consists.  He 
must  explain  to  them  how  upon  the  failure  of 
the  circulation,  the  function  of  the  brain  must 
cease  by  necessity  ;  that  if  the  cessation  of  the 
former  be  gradual,  that  of  the  latter  may  and 
often  does  precede  it ;  that  if  the  mortal  pro- 
cess begins  in  the  lungs,  unconsciousness  pre- 
cedes the  arrest  of  the  circulation ;  and  if  in 
the  brain,  that  an  injury  of  this  organ  sufficient 
to  affect  the  lungs  and  the  heart  fatally  is  sure 
to  annihilate  its  own  sensibility.  The  muscu- 
lar spasms,  the  slow,  gasping,  or  gurgling 
breathing,  the  collapsed  or  distorted  features, 
though  in  some  cases  accompanied  by  feeling, 
are  altogether  independent  of  it.  Convulsion 
is  not,  as  superficial  observers  often  interpret 
it,  the  sign  of  pain,  or  the  result  of  an  in- 
stinctive effort  of  nature  to  get  rid  of  the 
cause  of  pain, — it  is  an  affection  of  the  moti- 
fic  not  of  the  sensific  part  of  the  nervous  sys- 
tem.* The  pangs  of  the  disease  may  last  till 
within  a  short  period  of  death,  but  it  is  a 
great  error  to  attribute  them  to  the  process 
which  brings  them  to  an  end.  Such  cases 
however  are  rare ;  it  is  far  more  common  for 
the  sensibility  to  be  blunted,  or  for  the  cause 
of  pain  to  subside  before  the  phenomena  of 
dying  commence.  A  person  poisoned  by  an 
irritant  is  said  to  die  in  great  agony ;  a  very 
incorrect  expression,  since  death  in  such  cases 
is  ushered  in  by  coma  and  by  convulsions  un- 
attended with  pain.  Temporary  syncope  and 
asphyxia,  the  neatest  approaches  to  actual 
death,  have  nothing  formidable  in  sensation  if 
we  may  judge  from  the  reports  of  those  who 
have  experienced  them  ;  so  far  from  it  indeed, 
that  some  have  described  feelings  of  extreme 
pleasure,  connected  with  each  of  these  con- 
ditions.f 

The  relaxation  and  incapacity  of  the 
muscular  system,  though  for  the  most  part  ex- 
treme, has  in  some  cases  been  much  less  than 
might  have  been  expected ;  and  even  chronic 
maladies,  attended  during  their  course  with 
great  emaciation  and  debility,  have  suddenly 
terminated  when  the  patients  were  in  the  act  of 
walking,  or  of  performing  some  other  exertion 
disproportionate  to  the  rest  of  the  functions. 
The  condition  of  certain  muscles  in  the  last 
stage  of  existence  will  be  alluded  to  when  we 
come  to  speak  of  the  general  aspect  and  pos- 
•  ture  of  the  dying. 

The  voice  is  generally  weak  and  low  as 
death  approaches,  but  sometimes  has  a  shriller 
pitch  than  natural;  sometimes  it  is  husky  and 
thick,  and  not  unfrequently  it  dwindles  to  a 
mere  whisper.  These  changes  are  caused  prin- 
cipally by  the  debility  which  the  vocal  share 

*  Dr.  W.  Philip  has  some  excellent  remarks 
upon  this  subject  in  his  treatise  on  Sleep  and 
Death. 

t  See  Principes  de  Physiologic  Medicale,  par 
Isid.  Bourdon,  p.  319.  [It  was  either  Dr.  Black 
or  Dr.  Cullen  who  told  his  attendant  friends  that 
"  he  wished  he  could  be  at  the  trouble  to  tell  them 
how  pleasant  a  thing  it  was  to  die."  ED.] 


DEATH. 


801 


with  all  the  other  muscles  in  the  system.  In- 
terruptions of  the  voice  are  obviously  often  due 
to  the  state  of  the  respiration.  It  must  not  be 
omitted  that  in  some  instances  the  voice  has 
remained  firm  to  the  last. 

Of  the  signs  of  death  derived  from  the 
organic  functions,  the  tirst  in  importance  are 
those  belonging  to  the  circulation.  The  mode 
in  which  the  action  of  the  heart  declines  is 
extremely  various,  but  has  for  the  most  part 
some  connexion  with  the  nature  of  the  dis- 
order. In  maladies  of  considerable  duration, 
and  in  which  for  a  long  time  all  the  func- 
tions have  suffered  in  a  greater  or  less  degree, 
the  cessation  of  the  heart's  motion  is  nearly 
always  gradual.  The  number  of  pulsations 
may,  within  a  brief  period  of  decease,  greatly 
exceed  the  natural  rate,  but  their  energy  is 
impaired,  and  the  quantity  of  blood  expelled 
at  each  systole  is  very  small.  In  many 
acute  affections  the  failure  is  evidenced  some- 
times by  increased  frequency  and  diminished 
vigour  of  the  contractions,  and  sometimes  by 
their  irregularity  and  frequency,  the  force  being 
but  little  altered.  In  such  cases  the  cause  of  dis- 
turbance is,  without  doubt,  in  some  interruption 
of  the  nervous  connexions  of  the  organ.  In 
other  cases,  the  heart,  before  finally  ceasing  to 
beat,  contracts  with  great  violence,  and  then 
rapidly  and  suddenly  comes  to  a  stop.  We 
have  frequently  noticed  this  kind  of  action  in 
diseases  of  the  brain,  and  have  had  reason  to 
think  that  the  syncope  was  brought  on  by  the 
state  of  the  respiration ;  the  latter  effect,  how- 
ever, being  itself  due  in  no  slight  measure  to 
the  irregular  action  of  the  heart. 

The  increased  frequency  of  the  pulsations  in 
a  debilitated  state  of  the  heart  indicates  a  greater 
susceptibility  to  the  stimulus  of  the  blood,  at 
the  same  time  that  the  resulting  contractions 
are  less  efficient.  The  period  of  repose  be- 
tween the  diastole  and  the  systole  is  briefer 
than  in  the  normal  action,  besides  that  less 
time  is  occupied  by  the  systole  itself,  in  conse- 
quence perhaps  of  the  very  slight  shortening  of 
the  fibres.  In  a  vigorous'  heart  the  reverse  of 
this  takes  place;  the  irritability  is  not  such  as 
to  prevent  a  considerable  pause  after  the  dias- 
tole, and  the  fibres  undergo  a  much  greater 
degree  of  shortening.  Why  the  irritability  of 
a  part  should  increase  to  a  certain  extent  with 
increasing  debility,  is  a  problem  yet  to  be 
solved.  But  we  have  reason  to  think  that  it  is 
chiefly  in  acute  diseases  that  the  great  rapidity 
of  the  heart's  action  is  presented,  and  that  in 
chronic  affections  there  is  a  more  gradual  ex- 
haustion of  irritability.  Inequality  of  arte- 
rial action,  when  amounting  to  a  great  degree, 
is  one  of  the  most  threatening  symptoms  that 
can  be  witnessed.  We  allude  particularly  to 
that  extraordinary  pulsation  of  the  carotids 
which  is  sometimes  observable,  when  the  ra- 
dial artery  can  scarcely  be  distinguished.  It  is 
perhaps  one  of  the  strongest  presumptions 
that  arteries  possess  a  vital  contractility,  which 
may  be  disturbed  in  them  as  in  other  parts  of 
the  system. 

The  state  of  the  respiration  in  a  moribund 
person  is  extremely  various;  sometimes  hur- 


ried and  panting  till  within  a  few  moments  of 
decease;  sometimes  ceasing  gradually,  in  har- 
mony with  the  languishing  circulation ;  but 
sometimes  slow,  laborious,  and  stertorous, 
and,  as  Haller  expresses  it,  "  dum  anxietas 
equidem  cogit  moliri,  vetat  debi!itas.":*  In 
addition  to  those  causes  of  struggling  respira- 
tion which  belong  to  the  nervous  centres  and 
to  the  circulation  in  the  lungs,  the  function  is 
often  dreadfully  embarrassed  by  the  accumu- 
lation of  fluids,  mucous,  serous,  or  purulent, 
in  the  bronchia:.  The  quantity  of  these  secre- 
tions is  often  increased  by  a  state  of  the  bron- 
chial membrane,  analogous  to  what  we  shall 
notice"  presently  in  the  skin,  designated  by 
Laennec  "  the  catarrh  of  the  dying;"  but  the 
mere  accumulation  of  the  natural  quantity 
from  defect  of  those  muscular  actions  which 
usually  remove  it,  whether  in  the  fibres  of 
Keisseissen,  or  in  the  general  respiratory  appa- 
ratus, is  amply  suiricient  to  cause  exquisite 
distress.  Mediate  or  immediate  auscultation 
detects  a  loud  guggling  throughout  the  chest, 
which  is  sometimes  audible  even  at  a  little 
distance,  and  the  vibrations  of  which  may  be 
felt  by  the  hand.  This  sound  must  not  be 
confounded  with  the  true"  death-rattle,"  which 
is  produced  not  by  struggles  between  air  and 
liquid  in  the  bronchial  ramifications,  but  by 
the  ejection  of  air  from  the  lungs  through  the 
fluid  in  the  trachea.  It  is  often  followed  by 
a  flow  of  spumous  liquid  through  the  mouth 
and  nostrils. 

The  loss  of  animal  heat  occurs  first  in  the 
extremities, — a  fact  easily  explicable  by  the 
smaller  quantity  of  blood  sent  into  them  ;  but 
it  is  probable  that  the  state  of  the  nervous 
system,  and  the  cessation  of  the  nutritive  and 
other  capillary  actions,  which  perform  so  im- 
portant a  part  in  calorification,  may  participate 
in  the  production  of  the  result  in  question. 
The  recession  of  heat  from  the  limbs  was  no- 
ticed by  Hippocrates,  but  his  mode  of  stating 
the  fact  in  one  remarkable  passage,  his  !.i>t 
aphorism,  appears  considerably  affected  by  his 
theoretical  views  of  the  use  of  this  agent  in 
the  economy.f 

The  secretions  present  nothing  very  charac- 
teristic. If  the  disorder  has  been  of  short 
duration,  they  may  have  undergone  no  consi- 
derable change ;  but  when  the  declension  of 
life  has  been  more  gradual,  they  are  all  more 
.or  less  altered.  Tiie  bile  and  the  urine  are 
often  found  in  their  proper  receptacles,  of  a 
perfectly  healthy  character,  after  a  short  illness; 
while  in  senile  dissolution  t!iey  are  a!n;<»-t 
always  scanty  and  vitiated.  The  generation  of 
gas  in  large  quantities,  so  as  to  produce  tym- 
panites, is  a  very  common  occurrence  at  the 
termination  of  acute  diseases.];  We  have  al«> 
noticed  loud  borborygmi  during  the  last  few 
hours  of  life,  occasioned  by  large  collections 
of  air,  and  by  a  preternatural  excitement  of 
intestinal  irritability,  analogous  to  what  we 
have  noticed  in  the  heart  and  arteries.  The 

*  Elements  Physiologiae,  lib.  xxx.  $22. 
t    Hippocr.  Aph.   $  viii.  13. 
j  Hipp.  Aph.  §  viii.  17. 


802 


DEATH. 


secretion  of  saliva  is  almost  always  suppressed, 
and  the  mucus  about  the  mouth  and  nasal 
passages  is  so  deficient,  that  the  lips  and 
tongue  require  constant  moistening  when  arti- 
culation is  attempted ;  not  to  mention  the  inex- 
tinguishable thirst  which  is  one  of  the  most 
painful  forerunners  of  some  forms  of  dissolu- 
tion. The  perspirable  secretions  are  generally 
rather  profuse  than  scanty.  The  cutaneous 
surface,  particularly  about  the  face,  is  bedewed 
with  a  clammy  exudation.  It  cannot  be  said 
that  the  weakness  of  the  circulation  is  the 
immediate  cause  of  this  circumstance,  because 
it  frequently  happens  in  a  very  opposite  state 
of  the  function.  It  is  true  that  the  latler  fact 
has  been  explained  by  supposing  a  transuda- 
tion  of  the  thinner  part  of  the  blood  through  the 
coats  of  the  capillary  vessels  during  their  disten- 
tion,  while  the  former  has  been  attributed  to  a 
spasm  of  the  same  vessels,  consequent  on  the 
diminished  force  of  the  circulation,  and  said 
to  have  the  effect  of  squeezing  out  the  same 
serous  liquid.  In  each  case  we  must  presume 
the  perspired  fluid  to  be  in  a  state  of  separa- 
tion before  the  supposed  agency  can  come  into 
operation.  The  hypothesis  is  supported  by 
little  evidence ;  but  we  are  not  sure  that  any 
other  interpretation  can  be  found  much  more 
conclusive.  It  seems  probable,  however,  that 
the  fact  in  question  results  less  from  so  mecha- 
nical a  process  as  has  been  hinted  at,  than 
from  a  chemical  alteration  in  the  fluids,  in- 
duced perhaps  by  a  change  of  innervation,  in  a 
manner  analogous  to  those  extraordinary 
changes  which  the  secretions  so  frequently  pre- 
sent under  the  influence  of  mental  emotion. 

It  remains  for  us  to  enumerate  a  few  of  the 
signs  of  approaching  dissolution,  derived  from 
the  general  aspect  of  the  body.  Many  of 
these  have  been  described  by  Hippocrates  with 
unrivalled  accuracy.  The  sunken  eyes,  the 
hollow  temples,  the  sharpened  nose,  the  fore- 
head dry,  tense,  and  harsh,  the  complexion 
sallow,  livid,  or  black,  the  lips  cold,  flaccid, 
and  pale,  or  of  a  leaden  hue — compose  the 
celebrated  fades  Hippocrutica.*  All  these  signs 
admit  of  an  easy  rationale  by  the  state  of  the 
circulation  and  of  the  muscular  system.  They 
are  however  in  some  measure  due  to  the  con- 
dition of  the  cellular  tissue,  which,  indepen- 
dently of  its  loss  of  fat,  is  exhausted  of  that 
interstitial  fluid,  which  in  health  contributes  so 
much  to  the  firmness  and  equality  of  the  cu- 
taneous surface.  In  proof  of  this  we  may  men- 
tion that  all  the  appearances  enumerated  may 
be  produced  merely  by  a  violent  illness  of  a 
few  hours;  by  cholera  for  instance,  a  disease 
in  which  the  serous  fluid  is  rapidly  drained 
from  the  system  into  one  channel.  Excessive 
fatigue  and  fasting  will  occasion  appearances 
very  similar,  and  therefore  the  Father  of  Medi- 
cine recommends  us  to  ascertain  whether  such 
causes  have  been  in  action,  before  we  pro- 
nounce the  patient  to  be  moribund.  A  partial 
closure  of  the  eyelids  and  a  gaping  mouth 

*  These  signs  are  not  thus  grouped  together  in 
the  original,  but  are  individually  mentioned  in  the 
book  "  npoyvaju-Tixov,"  not  the 


are  signs,  when  conjoined  with  the  Others,  of 
fearful  import.  There  must  be  an  extreme 
depression  of  the  nervous  system  when  the 
orbicularis  is  unable  to  bring  the  lower  lid  into 
contact  with  the  upper,  which  has  drooped 
from  relaxation  of  the  levator  palpebrae,  and 
when  the  masseter  and  temporal  muscles  resign 
the  lower  jaw  to  gravitation.  A  supine  posi- 
tion with  the  limbs  extended,  and  a  tendency 
to  slide  down  to  the  lower  part  of  the  bed,  are 
indications  of  mortal  prostration.  In  the  pos- 
ture alluded  to  there  is  little  or  no  muscular 
exertion ;  for  the  extension  of  the  legs,  when 
the  body  lies  upon  the  back,  is  not  necessarily 
maintained  by  the  action  of  the  extensor  mus- 
cles, since  the  mere  support  of  the  surface  on 
which  they  rest  would  keep  them  in  that  posi- 
tion. The  sliding  down  in  the  bed  is  owing  to 
the  inability  of  the  glutaeal  muscles  to  resist 
the  gravitation  of  the  trunk  down  the  inclined 
plane,  upon  which  this  part  of  the  body  is 
extended  when  the  head  and  shoulders  are 
resting  upon  the  pillow.  When  the  prostration 
is  less  extreme,  it  often  happens  that  instead  of 
the  extremities  being  carried  forward  by  the 
impulse  alluded  to,  the  thighs  are  raised,  the 
knees  bent,  the  soles  rest  flat  upon  the  bed, 
and  the  heels  afford  a  sufficient  resistance  to 
the  nates  to  prevent  any  further  descent.  It  is 
evident  that  this  position  of  the  legs  and  thighs, 
though  requiring  a  muscular  effort  for  its  pro- 
duction, needs  little  or  none  for  its  mainte- 
nance. 

The  moribund  are  often  impatient  of  any 
kind  of  covering.  They  throw  off  the  bed- 
clothes, and  lie  with  the  chest  bare,  the  arms 
abroad,  and  the  neck  as  much  exposed  as 
possible.  These  actions  we  believe  to  be 
prompted  by  instinct,  in  order  that  neither 
covering?  nor  even  contact  with  the  rest  of  the 
body  may  prevent  the  operation  of  the  air 
upon  the  skin.  There  are  actions  and  re-ac- 
tions between  the  air  and  the  blood  in  the 
skin,  similar  to  those  which  occur  in  the 
lungs,  and  hence  in  asphyxial  disorders  the 
symptoms  alluded  to  are  very  marked;  but 
the  mere  influence  of  the  air  upon  the  cuta- 
neous nerves  has  been  proved  by  Dr.  Edwards 
to  be  beneficial  to  the  vital  powers.  Certain  it 
is  that  these  symptoms  are  sometimes  prominent 
in  cases  where  the  respiration  is  very  little  in- 
volved in  the  mortal  struggle.  Orfila,  in  one 
of  his  cases  of  poisoning  by  sulphuric  acid, 
mentions  that  the  subject  of  it  made  con- 
stant efforts  to  remove  even  the  lightest  kind 
of  covering. 

The  appearance  of  the  face  is  by  no  means 
such  as  we  have  described  it  above,  in  all  eases. 
The  kind  of  death  must  always  have  a  great 
influence  on  the  expression.  On  fields  of 
battle  the  corpses  of  those  who  died  of  stabs 
are  easily  distinguished  by  the  countenance, 
from  those  who  fell  by  gun-shot.  In  the  for- 
mer an  extremely  painful  impression  must 
have  been  transmitted  to  the  brain,  which  pro- 
duced the  usual  change  in  the  nerves  and 
muscles  of  expression;  in  the  latter  a  con- 
cussion was  given  to  the  whole  system,  para- 
lysing without  any  intermediate  sensation,  so 


DEATH. 


803 


that  no  expression  remained  moro  than  that  of 
the  repose  of  the  muscles.  The  nature  of  the 
disease  also  modifies  the  facial  expression  of 
the  dying.  In  some  we  observe  the  impivss 
of  the  previous  suffering,  as  in  peritonitis  and 
in  cases  of  poisoning  by  irritants ;  in  others 
the  character  is  derived  from  a  peculiar  affec- 
tion of  some  part  of  the  respiratory  apparatus, 
as  of  the  diaphragm  in  pericarditis ;  or  from 
an  affection  of  the  facial  muscles  themselves, 
as  in  tetanus  and  paralysis.  But  the  condition 
of  the  mind  is  perhaps  more  often  concerned 
in  the  expression  than  even  the  physical  cir- 
cumstances of  the  body.  For,  as  some  kind 
of  intelligence  is  frequently  retained,  and 
strong  emotions  are  experienced  till  within  a 
few  moments  of  dissolution,  the  features  may 
be  sealed  by  the  hand  of  death  in  the  last  look 
of  rapture  or  of  misery — of  benignity  or  of 
anger.  Every  poetical  reader  knows  the  pic- 
ture of  the  traits  of  death  (no  less  true  than 
beautiful)  drawn  by  the  author  of  the  "Giaour." 
But  such  observations  are  not  confined  to 
poets.  Haller  could  trace  in  the  dying  coun- 
tenance the  smile  which  had  been  lighted  by 
the  hope  of  a  happier  existence  :  "  Adfttl- 
gcntis  Jligicnti  aninue  spei  non  ruro  in  inori- 
humlis  signa  vidi,  qui  scrcnissinio  vultu,  mm 
sine  blando  subrisu,  de  vita  excesserunt"* 
Watchers  of  the  dead  have  often  affirmed,  and 
we  can  ourselves  testify  to  the  fact,  that  a 
smile  has  appeared  upon  the  countenance  some 
hours  after  death,  though  no  such  expression 
had  been  witnessed  at  the  time  of  the  event ; 
which  is  not  difficult  of  interpretation  if  we 
consider  that  an  extremely  slight  muscular 
action  is  sufficient  to  give  any  kind  of  expres- 
sion, particularly  that  of  complacency, — that 
mortal  rigidity  is  produced  by  a  species  of 
contraction  in  muscular  fibres,  (to  be  discussed 
more  fully  hereafter),  and  that  this  change 
seldom  takes  place  till  several  hours  after 
death. 

SIGNS    OF    ACTUAL    DEATH. 

The  discrimination  of  true  from  apparent 
death  is  not  a  matter  of  mere  physiological 
interest.  It  is  of  great  importance  that  the 
medical  practitioner  should  be  able  to  decide 
in  doubtful  cases  whether  the  resources  of  art 
may  be  dispensed  with,  or  the  rites  of  sepul- 
ture be  permitted,  as  well  as  to  give  evidence, 
in  certain  medico-legal  inquiries,  of  the  pre- 
cise period  at  which  an  individual  expired. 
We  have  not  space  to  record  the  numerous 
cases  that  may  be  met  with  in  various  authors, 
proving  that  even  the  most  sagacious  and  ex- 
perienced observers  have  been  at  times  de- 
ceived as  to  the  reality  of  death.  In  the  works 
of  the  ancients  there  are  frequent  allusions  to 
premature  interments.  Pliny  has  a  chapter, 
"  De  his  qui  elati  revixerunt ;"  and  among 
other  cases  mentions  that  of  a  young  man  of 
rank,  who  was  revived  by  the  heat  of  his 
funeral  pyre,  but  who  perished  before  he  could 
be  rescued  from  the  flames.  "  Ilaec  est  con- 
ditio  morlalium,"  is  the  reflection  of  the  phi- 
losopher, "  ad  hasce  ejusmodi  occasiones  for- 

*  Elem.  Phys.  lib.  xxx,   $  23. 


tunic  gignimur,  nt  do  hoinine  nc  morti  quidein 
debeat  credi."  C'olsus  asks,  "  si  certa  futur.r 
mortis  indicia  sunt,  qiu»inod«»  inh'rdum  de- 
scrti  a  nn-dicis  rom;il"«  ant,  qnosdamqm 
fama  prodiderit  in  ipsis  funeribus  reviv 
"  Complura  fuerunl  exempla,"  says  Lord 
Bacon,  "  hominum,  tanquam  mnrtunrum  aut 
expositorum  a  lecto,  aut  di-latorurn  ad  In  mis, 
quinctiam  nommllorum  in  terra  conditorum, 
qui  nihilominus  revixerunt."* 

In  the  writings  of  VVinslowf  and  BruhierJ 
will  be  found  an  ample  collection  of  melan- 
choly instances  of  premature  interment,  busidrs 
those  which  are  scattered  through  various  sys- 
tematic works  upon  forensic  medicine.  Un- 
intentional vivisection,  moreover,  has  befallen 
other  instances  than  the  celebrated  subject 
of  Vesalius.  Few  of  our  readers  have  i>ot 
shuddered  at  the  tale  of  the  dismal  fate  of 
the  Abbe  Prevost,  who,  having  been  struck 
with  apoplexy  in  the  forest  of  Chantilly,  was 
taken  home  for  dead,  but  recovered  his  con- 
sciousness under  the  scalpel,  and  died  im- 
mediately afterwards.  We  must  not  recount 
the  marvellous  recoveries  recorded  by  French 
authors,  of  Madame  Mervache,  the  wife  of  a 
jeweller  at  Poitiers,  who  was  restored  to  life 
in  her  grave,  by  the  attempts  of  a  robber  to 
despoil  her  of  the  rings  with  which  she  had 
been  buried ;  and  of  Francois  Civille,  a  Nor- 
man gentleman,  whose  custom  it  was  to  add 
to  the  signature  of  his  name,  "  trois  fois  mort, 
trois  fois  enterre",  et  trois  fois  par  la  grace  de 
Dieu  ressuscite."  The  English  reader  will 
find  an  interesting  selection  of  cases  in  the 
Appendix  to  Dr.  Smith's  Principles  of  Fo- 
rensic Medicine,  and  in  the  article  Premature 
Interments  in  the  Encyclopaedia  Britannica. 
We  shall  only  add  tliat  Bruhier  collected  fifty- 
two  cases  of  persons  buried  alive,  four  of  per- 
sons dissected  prematurely,  fifty-three  of  per- 
sons who  recovered  without  assistance  after 
they  were  laid  in  their  coffins,  and  seventy-two 
falsely  reported  dead.§ 

We  shall  arrange  the  indications  of  death 
under  three  heads  : — 

1st.  Signs  of  the  extinction  of  vital  functions 
and  properties. 

2dly.  Changes  in  the  tissues. 

3dly.  Changes  in  the  external  appearance  of 
the  body. 

1.  The  arrest  of  the  circulation  and  respi- 
ration would  at  first  appear  to  afford  decisive 
evidence  that  a  person  is  no  longer  alive.  But 
this  sign  is  liable  to  the  two-fold  objection  that 
we  cannot  distinguish  with  absolute  certainty 
the  minimum  of  the  functions  mentioned, 
from  their  complete  annihilation,  and  that  re- 
coveries have  taken  place  after  their  real  or 

•  Hist.  Vitae  et  Mortis,  §  x. 

t  Dissert,  an  mortis  inccrta  sint  indicia. 

}  Dissert,  sur  1'Inccrtitude  dcs  signes  de  la  mort. 

§  Louis  in  his  Lettrcs  sur  la  Certitude  des  signes 
de  la  mort,  insinuates  that  some  of  Bruhier's  cases 
arc  apocryphal.  A  more  recent  and  perhaps  a 
more  authentic  collection  of  cases  will  be  found  in 
M.  Julia  de  Fontcncllc's  "  Recherchcs  medico- 
Impales  sur  1'incertitude  des  si^ncs  de  Id  mort/'  &c. 
1834. 


804 


DEATH. 


apparent  cessation.  The  case  of  Colonel 
Townshend,  related  by  Cheyne,*  is  too  well 
known  to  need  recital  here.  Perhaps  the  most 
unequivocal  examples  of  their  suspension  are 
certain  cases  on  record  of  restoration  after  sub- 
mersion for  several  minutes.  In  some  of  these 
there  is  good  reason  to  believe  that  there  was 
no  genuine  asphyxia,  but  that  syncope  took 
place  immediately,  and  consequently  that  there 
was  no  stagnation  of  blood  in  the  extremities 
of  the  pulmonary  arteries.  As  to  the  alleged 
cases  of  persons  who  have  been  said  to  lie 
many  hours  and  even  days  without  pulse  or 
breathing,  we  do  not  hesitate  to  express  a 
belief  that  the  observers  were  deceived,  and 
that  in  reality  both  these  functions  were  per- 
formed, but  in  so  low  a  degree  as  to  escape 
detection,  just  as  hybernating  animals  were 
supposed  to  be,  during  their  torpor,  in  the  pre- 
dicament alluded  to,  until  the  researches  of 
Dr.  M.  Hall  proved  that  these  animals  do 
actually  respire  and  maintain  their  circulation, 
though  in  a  much  less  degree  than  when 
awake.  It  will  be  the  duty  of  the  practitioner 
to  adopt  every  method  within  his  reach  of 
ascertaining  the  actual  condition  of  these  func- 
tions; but  he  must  remember  that  they  are 
often  inefficient  and  even  fallacious.  Thus, 
with  regard  to  the  common  modes  of  trying 
the  respiration  by  a  mirror,  or  by  light  downy 
bodies  placed  near  the  mouth  and  nostrils, 
it  is  obvious  that  the  former  may  retain  its 
clearness,  because  the  halitus  is  not  in  suf- 
ficient quantity  to  stain  it,  or  may  be  dimmed 
by  exhalations  from  the  air-passages  which  are 
not  the  products  of  respiration ;  and  that  the 
downy  substances  may  be  stirred  by  currents 
of  air,  or  remain  unmoved  by  the  trivial  ex- 
change which  takes  place  between  the  external 
atmosphere  and  the  air  in  the  chest  of  the 
person  examined.  Winslow's  test  of  a  vessel 
full  of  water  placed  on  the  lowest  part  of  the 
thorax  is  of  little  utility,  since  we  know  that 
the  diaphragm  may  be  the  only  muscle  em- 
ployed in  expanding  the  chest.  As  to  the 
circulation,  it  may  continue  though  no  pul- 
sation can  be  felt  over  the  arteries  or  the  car- 
diac region,  and  no  sound  be  perceptible  by 
auscultation  mediate  or  immediate.  Few  prac- 
titioners would  be  willing  to  apply  M.  Fou- 
bert's  test,  to  wit,  that  of  making  an  incision 
in  one  of  the  intercostal  spaces,  and  feeling 
the  heart  with  the  finger ! 

The  loss  of  irritability  in  the  muscular  fibres 
is  of  far  greater  consequence  than  either  of  the 
foregoing  signs.  It  may  be  present  when  re- 
covery is  out  of  the  question,  but  its  absence 
is  quite  conclusive.  Galvanism  affords  a  cer- 
tain and  ready  method  of  detecting  this  pro- 
perty. According  to  the  researches  of  Nystenf 
irritability  is  first  extinguished  in  the  left  ven- 
tricle ;  after  forty-five  minutes  it  has  left  the 
intestines  and  stomach  ;  a  little  later  the  blad- 
der; after  an  hour  the  right  ventricle  ;  after  an 
hour  and  a  half  the  oesophagus;  after  an  hour 

..    *  English  Malady,  page  307. 

t  Recherches  dc  Physiologic  et  de  Chimie  Pa- 
thologique. 


and  three  quarters  the  iris.  It  next  takes  leave 
of  the  muscles  of  the  trunk,  then  the  lower 
and  upper  extremities,  and  lastly  the  right 
auricle.  The  duration  of  contractility  is  short- 
ened by  a  warm  and  humid  state  of  the  at- 
mosphere, by  ammoniacal  gas,  carbonic  acid, 
and  sulphuretted  hydrogen.  It  is  unaffected  by 
carburetted  hydrogen,  chlorine,  and  sulphur- 
ous acid ;  nor  is  it  found  diminished  in  cases 
of  asphyxia  by  strangulation  and  immersion. 
The  annihilation  of  that  particular  kind  of 
contractility  of  tissue,  which  is  equally  dis- 
tinct from  muscular  contractility,  irritability, 
and  elasticity,  is  one  of  the  surest  signs  of 
death.  We  see  it  wanting  in  the  collapsed 
edges  of  a  wound  which  has  been  inflicted  on 
the  skin  of  a  dead  body,  as  contrasted  with 
the  gaping  appearance  of  a  similar  lesion  made 
during  life. 

The  loss  of  animal  heat,  though  an  invariable 
occurrence  at  some  period  after  death,  is  not 
unfrequently  noticed  in  disease.  Every  prac- 
titioner must  have  met  with  it  in  hysterical 
cases;  and  it  is  a  matter  of  notorious  obser- 
vation in  cholera.  On  the  other  hand  we  have 
known  the  heat  of  the  body  not  only  continue 
but  even  return  at  a  considerable  period  after 
death  has  unequivocally  taken  place ;  a  fact 
attributable  either  to  chemical  actions  of  a 
cadaveric  description,  or  to  the  continuance  of 
the  processes  which  developed  caloric  during 
life.  The  mean  time  requisite  for  the  com- 
plete cooling  of  the  body  is  fifteen  or  twenty 
hours ;  but  the  process  is  modified  by  a  great 
variety  of  circumstances.  It  is  slower  after 
acute  than  chronic  maladies,  but  is  very  con- 
siderably retarded  in  asphyxial  cases,  except 
those  occasioned  by  submersion. 

Calorification  is  not  the  only  function  that 
may  survive  what  is  commonly  called  death  ; 
thus  the  rectum  and  bladder  have  been  known 
very  frequently  to  discharge  their  contents 
after  death ;  and,  which  is  still  more  remark- 
able, parturition  has  taken  place  under  such 
circumstances.  The  continuance  of  secretion, 
absorption,  and  nutrition  has  been  argued 
from  the  exhalation  of  serous  fluids  in  some 
parts,  their  disappearance  in  others,  and  the 
alleged  growth  of  hair.  Some  of  these  facts 
are  more  rationally  explained  on  such  physical 
principles  as  are  involved  in  transudation, 
endosmose,  penetration,  &c.  &c. ;  as  to  the 
growth  of  hair,  there  is  great  reason  to  doubt 
the  accuracy  of  the  testimonies  to  the  fact. 
Haller  very  justly  observes  that  shrinking  of 
the  skin  would  produce  an  apparent  elongation 
of  the  beard,  which  is  the  part  upon  which 
the  observation  alluded  to  has  been  most  fre- 
quently made. 

2.  The  first  alterations  in  the  physical  pro- 
perties of  the  solids  after  death  are  softness 
and  flexibility,  to  which  succeed  sooner  or  later 
the  opposite  conditions  of  firmness  and  rigi- 
dity. The  softness  or  want  of  elasticity  may 
be  owing  partly  to  differences  in  the  distri- 
bution of  the  fluids  in  the  tissues,  and  partly 
to  changes  in  the  tissue  itself.  The  flattening 
of  those  parts  upon  which  the  weight  of  the 
body  rests,  the  effect  of  deficient  elasticity, 


DEATH. 


805 


is  considered  by  Blumenbach  a  valuable  cri- 
terion of  the  reality  of  death.  The  flexibility 
of  the  joints  obviously  depends  upon  the  re- 
laxation of  the  muscles. 

Rigidity    is  a  change  which    has   attracted 
great  attention  from  its  importance  as  an  evi- 
dence of  death.     Its   period  of  accession  de- 
pends principally  upon  the  nature  of  the  ma- 
lady.     After  long   and   exhausting   illnesses, 
its  appearance  is  early,  but  the  duration  is  brief, 
and  the  intensity  trifling.     The  same  remark 
applies  to  the  modifying  influence  of  old  age. 
When  the  individual  has  been  cut  off  by  sud- 
den accidental   causes   or   by  acute  diseases, 
it  comes  on  for  the  most  part  much  later,* 
lasts  longer,  and  is  more  intense  than  in  the 
former  instances.     It  may  appear  within  half 
an  hour  after  death  or  may  be  delayed  twenty 
or  thirty  hours,  according  to  the  circumstances 
just  mentioned.     The  mean  duration  is  from 
twenty-four  to  thirty-six  hours  ;   but   it  may 
last  six  or   seven  days  according  to  Nysten, 
whose  researches  upon  this   subject  are  very 
valuable.     \Ve  remember  observing  it  once  on 
the  eighth  day  after  death  in  the  body  of  a 
criminal  who  had  been  executed  by  hanging, 
but  are  not  aware  at  what  time  it  had  com- 
menced.     The  parts  which   first  present  this 
change  are  the  neck  and  trunk  ;  it  then  appears 
in   the  lower  extremities,    and   lastly    in   the 
upper.     Its  departure  observes  the  same  order. 
it  is  yet  to  be  proved  that  rigidity  is  not  an 
invariable  consequence  of  death.     Nysten  at- 
tributes Bichat's  assertion  of  its  non-appear- 
ance in  some  cases  of  asphyxia,  to  the  lateness 
of  its  developement.     If  it  could  be  wanting 
in  any  case,  it  would  probably  be  so  in  sub- 
jects attenuated  and  of  flabby  fibre.     Louis  in 
hisLetterson  the  Certainty  of  the  Signs  ofDeath 
declares  that  he  never  found  it  absent  even  in 
the  infirm  and  age-worn  patients  of  Salpetriere, 
and  Fodere  gives  a  similar  testimony  to  its 
universality.f 

The  seat  of  rigidity  is  the  muscular  sub- 
stance. Of  this  we  may  be  assured  by  the 
following  facts.  (1).  It  is  observed  in  all  those 
animals  (including  many  of  the  invertebrata) 
which  have  a  distinct  muscular  tissue.  (2).  Its 
intensity  is  in  a  direct  ratio  with  the  develope- 
ment of  this  tissue.  (3).  It  is  destroyed  by 
division  of  the  muscles,  a  fact  first  noticed  by 
Nysten.  J  (4).  It  remains  when  the  cellular 
membrane,  skin,  aponeurosis,  and  ligaments 
are  removed.§  (5).  When  very  strong,  it  ren- 
ders the  muscles  prominent  as  in  voluntary 
contraction,  or  in  that  spasm  which  is  induced 
by  rammollissement  of  the  brain  and  spinal 
marrow.  Ch.  Louis  makes  a  remark  of  this 
kind  in  his  admirable  memoir  upon  some  cases 
of  sudden  death.|| 

In  hemiplegiac  subjects  rigidity  is  observed 

*  We  very  recently  however  observed  the  phe- 
nomenon only  an  hour  and  a  half  after  the  death 
of  a  boy  by  acute  peritonitis. 

t  Med.  Leg.  t.  ii.  p.  361. 

t  Rech.  de  Physiol.  et  Pathol.  Chim. 

§  Devergie,  Diet,  de   Med.  et  Chir.  Prat.   Art, 
Mort. 
'   ||  Rech.  Anat.  Path.  p.  500. 


to  be  no  less  stiouy;  in  the  paralysed  limbs 
than  in  those  which  were  unaffected  by  the 
disease.  The  temperature  of  the  !:od\  has  been 
said  to  inihitMicv  it.  Keebni :  Bp  aka  of  cooling 
as  being  always  antecedent  to  rigidity,  and 
Nysten  has  made  a  similar  statement.  But  we 
have  hud  many  opportunities  of  disproving  tins 
observation.  Ch.  Louis  noticed  the  pheno- 
menon in  some  of  the  cases  just  adverted  to, 
while  the  bodies  were  quite  warm.  Its  occur- 
rence in  cold-blooded  animals  is,  we  think,  a 
sufficient  refutation  of  the  idea  that  it  bears 
any  necessary  relation  with  the  loss  of  heat. 
Moreover  Devergie  has  very  properly  pointed 
out  the  inconsistency  of  this  notion  with  the 
fact  that  rigidity  appears  first  upon  the  trunk, 
the  region  which  is  the  last  to  be  deserted  by 
calor.c. 

The  cause  of  rigidity  is  referred   by  most 
authors  to  a  sort  of  lingering  vital  contraction. 
It  is  often  spoken  of  as  the  last  efibrt  of  life: 
"  II   semble  que  la  vie,"  says  Nysten,    *'  se 
rei'ugie  en  dernier  lieu  dans  ces  organes,   et 
y  determine  le  spasme  qui  constilue  le   roi- 
deur."  f  This  author  not  only  refers  it  to  con- 
traction, but  endeavours  to  explain  how  a  very 
low  degree  of  the  ordinary  kind  of  contraction 
may  be  sufficient  to  stiffen  the  muscles  though 
not  to  move  the  part  with  which  they  are  con- 
nected. Supposing  that  a  muscular  efibrt  equal 
to  20  would  completely  bend  the  elbow,  one 
equal  to  10  would  serniflex  it;  one  equal  to 
5  would  bend  it  a  quarter  of  the    distance ; 
while  aforce equal  to  l-20th  only,  would  perhaps 
produce  no  motion  at  all,  nothing  but  rigidity  ! 
Beclard  alleges  three  causes ;  the  last  contrac- 
tion of  muscular  fibres,  the  general  cooling  of 
the  body,  and  the  coagulation  of  the  fluids. 
The  second  of  these  we  have  already  disposed 
of.     Notwithstanding  the   high  authorities  in 
favour  of  the  opinion  that  rigidity  is  caused 
by  a  vital  contraction,  we  confess  that  to  us  it 
appears  a  very  untenable  position.     All  mus- 
cular contraction  in  its  normal  condition  alter- 
nates with  relaxation;  and  although  rigidity 
might  be  supposed  to  bear  some  analogy  to 
the  tonic  spasm  of  tetanus,  it  differs  widely 
from  the  latter  in  one  important  respect,  that 
when  overcome  by  violence  it  does  not  return. 
When   we   consider  that  the    continuance   of 
the    phenomenon    in    question    is  long  after 
the   cessation   of  any   vital  action;    that  the 
umal    time   of  its  accession  is  precisely  that 
which  we  have  every  reason  to  consider  the 
most  unfavourable  for   the  occurrence   of  any 
vital  action,  viz.  when  all  animal  heat  is  ex- 
tinct, and  when  sanguineous  congestions  in  the 
depending  parts  of  the  body  prove  the  capil- 
laries to  have  lost  their  contractility;  it  is  diffi- 
cult to  regard  the  process  as  of  a  vital  cha- 
racter.   The  mere  fact  that  the  rigidity  comes 
on  and  remains  long  after  the  muscles  have 
ceased  to  respond  to  the  stimulus  of  galvanism, 
reduces  the  hypothesis  to  the  last  degree  of 
improbability.     Moreover  we  should  scarcely 
expect  the  last  act  of  life  to  be  performed  in 

*  Anatomic  Generate,  p.  127. 
t  Op.  cit.  §v.  art.  3. 


806 


DEATH. 


the  extremities ;  we  should  naturally  look  for 
it  about  the  trunk,  in  conformity  with  the  order 
of  disappearance  observed  by  all  other  vital 
actions ;  but  as  we  have  stated  above,  this  phe- 
nomenon both  appears  and  declines  h'rst  upon 
the  trunk;  in  other  words,  according  to  the 
hypothesis,  the  muscles  in  this  part  expire 
while  those  of  the  extremities  are  still  alive. 
Devergie  is  puzzled  to  reconcile  the  long 
continuance  and  intensity  of  rigidity  in  cases 
of  asphyxia  from  carbonic  acid,  with  the 
fact  that  this  agent  is  destructive  to  contrac- 
tility. We  are  somewhat  surprised  that  he 
was  not  brought,  by  the  mutual  opposition  of 
these  facts,  to  consider  that  rigidity  and  vital 
contraction  have  nothing  in  common  but  the 
tissue  in  which  they  are  manifested. 

The  third  cause  enumerated  by  Beclard  is 
the  coagulation  of  the  blood.  This  is  probably 
nearer  the  truth  than  are  the  other  explanations 
of  the  phenomenon  ;  but  it  would  be  more 
correct  to  say  that  rigidity  and  coagulation  of 
the  blood  are  effects  of  the  same  causes,  viz. 
coagulation  of  fibrin.  They  occur  about  the 
same  time,  and  are  impeded  by  the  same 
agents.  It  has  been  proved  that  the  muscles 
are  the  subjects  of  the  rigidity,  that  they  are 
contracted,  and  that  their  contraction  is  not  of 
a  vital  nature.  As  this  change  must  there- 
fore be  either  mechanical  or  chemical,  what 
more  probable  cause  (in  the  absence  of  actual 
demonstration)  can  be  imagined  than  the  coa- 
gulation of  fibrin  in  the  muscles? 

The  rigidity  occasioned  by  certain  diseases 
may  be  mistaken  by  an  unpractised  observer 
for  mortal  stiffness.  This  error  is  most  likely 
to  be  committed  in  cases  of  hysteria,  for  this 
affection,  not  content  with  imitating  almost 
every  other  malady,  has  been  often  successful 
in  mimicking  death  itself.  Tetanus  is  in- 
stanced by  some  authors  as  a  disease  likely  to 
occasion  mistakes  of  the  kind  alluded  to.  This 
may  be  true  of  hysteric  tetanus,  but  not  of  the 
idiopathic  or  of  the  traumatic  species,  which 
have  characters  too  striking  to  be  overlooked 
by  even  the  most  inexperienced.  Besides,  if 
the  rigidity  of  any  given  case,  supposed  by  one 
to  be  cadaveric,  were  by  another  proved  to  be 
tetanic,  we  are  of  opinion  that  the  condition  of 
the  subject  would  be  not  a  whit  less  hopeless, 
since  the  case  implies  that  the  respiration  and 
circulation  are  apparently  extinct;  and  when 
this  is  the  case  in  tetanus,  we  may  feel 
quite  certain  that  if  the  patient  is  not  actually 
dead,  he  is  quite  irrecoverable.  Nysten  de- 
clares that  the  rigid  spasm  of  disease  may 
be  always  distinguished  from  that  of  death  by 
the  circumstance  that  it  precedes  the  loss  of 
heat  in  the  former  case,  while  hi  the  latter  the 
order  of  the  events  is  just  the  reverse.  This 
test  holds  good  in  a  very  large  proportion  of 
cases,  but  must  not  be  implicitly  relied  upon, 
because,  as  we  have  before  observed,  corpses 
not  unfrequently  retain  their  caloric  for  some 
time  after  rigidity  has  commenced.  A  better 
criterion  is  that  of  overcoming  the  rigidity 
by  force ;  if  it  be  cadaveric,  the  contraction 
is  completely  annihilated;  if  morbid,  it  will 
return  when  the  force  is  withdrawn. 


A  species  of  rigidity  more  likely  to  be  con- 
founded with  the  cadaveric  is  that  which  is 
sometimes  found  in  the  dead  body,  but  which 
is  the  product  of  disease.  Of  this  description 
is  the  spasmodic  contraction  which  often  con- 
tinues after  death  by  apoplexy  and  other  cere- 
bral and  spinal  diseases ;  and  the  observation 
of  which  is  as  old  as  the  time  of  Hippocrates. 
M.  Marc  relates  the  case  of  a  gentleman  who 
went  to  a  theatre  apparently  in  good  health, 
and  after  the  representation  was  over,  was 
found  by  his  friends  sitting  in  the  front  of  the 
box,  with  his  head  resting  upon  his  hands,  and 
his  elbows  on  the  ledge.  He  had  died  of  apo- 
plexy, and  been  retained  in  that  position  by 
the  tonic  spasm  of  his  muscles.*  This  con- 
traction is  unquestionably  vital,  but  it  ceases 
after  a  few  hours,  and  the  flexibility  is  then 
succeeded  by  true  cadaveric  rigidity.  In 
medico-legal  cases  it  is  of  the  utmost  moment 
to  bear  this  distinction  in  mind,  but  it  is  one 
that  has  received  much  too  little  attention. 
Many  of  the  standard  works  upon  forensic 
medicine  are  altogether  silent  upon  the  subject. 
Its  importance  was  proved  by  a  case  which 
occurred  in  France  some  years  ago.  The  body 
of  a  man  named  Courbon  was  found  in  a  ditch, 
with  the  trunk  and  limbs  in  such  a  relative 
position  as  could  only  have  been  maintained 
by  the  stiffness  of  the  articulations.  This 
stiffness,  moreover,  must  have  come  on  at 
the  very  time  when  the  body  took  the  said 
position,  unless  it  could  be  imagined  that  the 
body  had  been  supported  by  the  alleged  mur- 
derers until  the  joints  were  locked  by  cada- 
veric stiffness,  a  supposition  infinitely  too  im- 
probable to  be  entertained  for  an  instant.  But 
by  regarding  the  rigidity  as  of  a  spasmodic 
nature  (resulting  from  apoplexy,  of  which  there 
were  sufficient  proofs  in  the  necroscopy),  the 
difficulties  of  the  case  were  altogether  removed. 
A  full  report  of  the  case,  and  of  the  medico- 
legal  consultation  upon  it,  will  be  found  in  the 
seventh  volume  of  the  Annales  d'  Hygiene.  In 
death  by  asphyxia  there  is  often  a  spasmodic 
contraction  which  may  continue  for  some  time 
after  decease.  Orfilaf  is  of  opinion  that  this 
may  be  readily  distinguished  by  the  continu- 
ance of  animal  heat,  which  he  agrees  with 
Nysten  in  judging  to  be  incompatible  with 
rigidity.  While  denying  the  universality  of 
this  principle,  we  think  it  sufficiently  extensive 
to  admit  of  a  very  useful  application  in  a  great 
number  of  instances. 

From  what  has  been  said,  it  can  scarcely 
be  doubted  that  rigidity  is  a  certain  evidence 
of  death.  Prior  to  this  there  is  no  indication 
derivable  from  changes  in  the  tissues  which 
can  be  depended  upon ;  but  the  flexibility  that 
follows  it  affords,  if  possible,  still  stronger 
proof  of  the  condition  of  the  body.  There  is 
no  state  with  which  it  can  be  confounded  if 
we  except  the  interval  between  spasmodic  and 
true  post-mortem  stiffness ;  but  very  little  cau- 
tion is  requisite  for  avoiding  a  fallacy  of  this 
description. 

*  Annaks  d'  Hygiene,  &c.  t.vii.  p.  604. 
t  Le§ons  de  Med.  Leg.  t.  ii.  p.  195. 


DKATTI. 


807 


The  next  remarkable  change  winch  takes 
place  in  the  tissues  is  putrefaction,  ;i  process 
in  which  the  ultimate  elements  of  the  body, 
operated  upon  by  external  causes,  enter  into 
combinations  incompatible  with  the  existence 
of  those  proximate  principles  of  which  the  tex- 
tural  molecules  are  compounded.  Some  phy- 
siologists conceive  that  even  putrefaction  is 
not  a  necessary  sign  of  death.  Winslow, 
however,  pronounces  it  "  unicum  signnm ;" 
and  Bruhier  expresses  a  similar  opinion.  IJal- 
ler*  says  that  it  may  commence  in  a  living 
person,  but  that  death  must  be  very  near  at 
hand.  He  relates  of  one  Vandenhoeck,  his 
bookseller,  that  when  lying  in  the  last  stage  of 
a  malignant  fever,  lie  prophesied  his  approach- 
ing end,  and  that  he  grounded  his  prediction 
upon  his  sense  of  smell.  Orfila,  one  of  the 
greatest  authorities  upon  this  subject,  considers 
the  commencement  of  putrefaction  a  less  un- 
equivocal sign  than  true  rigidity  ;  his  opinion 
rests  upon  the  fact  that  he  has  known  persons 
completely  recovered,  notwithtsanding  the  skin 
was  covered  with  violet  spots,  which  exhaled 
an  infectious  odour.f  It  is  remarkable  that  so 
acute  an  observer  should  have  overlooked 
what  seems  a  very  obvious  consideration,  viz. 
that  these  violet  spots  being  caused  by  extra- 
vasated  blood,  perhaps  in  a  state  of  decom- 
position, afford  no  indication  that  putrefaction 
lias  begun  in  the  solids.  Sphacclus,  though 
consisting  in  decomposition,  need  not  be  con- 
founded with  putrefaction.  The  latter  change 
begins  always,  according  to  the  observation  of 
M.  Devergie,  either  upon  the  abdomen  or  the 
thorax,  and  has  the  appearance  of  a  large 
diffused  patch  of  a  green  colour,  which  after- 
wards becomes  brown.  The  brown  portion  is 
surrounded  by  a  green  areola  indicating  the 
extension  of  the  process.  Into  the  history  of 
putrefaction  we  cannot  enter,  but  must  refer  to 
the  valuable  "  Exhumations  Juridiques "  of 
MM.  Orfila  and  Lesueur,  and  to  some  papers 
by  M.  Devergie  in  the  second  volume  of  the 
Ann.  d'lJvgiene  on  the  changes  in  the  bodies 
of  persons  drowned,  and  also  to  a  controversy 
upon  the  latter  subject  between  this  author  and 
M.  Orfilu,  in  the  fifth  and  sixth  volumes  of  the 
same  work.]; 

After  the  decomposition  has  advanced  to  a 
certain  stage,  but  sometimes  without  any  putre- 
faction at  all,  the  tissues,  instead  of  being  dissi- 
pated by  conversion  into  liquid  and  gaseous 
substances,  which  is  the  essential  part  of  the 
putrefactive  process,  may  be  converted  into 
solid  matters  widely  differing  from  the  original 
molecules.  (See  ADIPOCERE  and  MUMMI- 
FACTION.) 

3.  We  have  lastly  to  notice  a  few  signs  of 
the  reality  of  death  gathered  from  the  external 
aspect  of  the  body.  The  appearance  of  the 
face  has  been  already  described  among  the 
signs  of  the  moribund  state.  We  have  only 
to  mention  in  addition,  that  instead  of  the 

*  Op.  et  loc.  citat. 

t  Op.  cit.  t.  ii.  p.  231. 

$  Devergie's  papers  are  embodied  together  with 
more  recent  observations  in  (lie  first  volume  of  his 
"  .\Kdccinc  Li-gale,"  published  a  few  months  ago. 


paleness  or  lividity  that  were  present  at  the 
tune  of  death,  a  rosy  hue  may  appear  upon 
tlie  eliceks,  which  has  not  unfrcqiu'iitly  (xv;i- 
sioned  a  deceitful  hope  that  life.  v\:is  not  vet 
extinct.  The  cause  was  very  rationallv  as- 
cribed by  Mr.  Chevalier  to  the  action  of  at- 
mospheric air  upon  the  blood  accumulated  in 
the  capillaries.  This  phenomenon  is  more 
likely  to  occur  when  syncope  has  followed 
asphyxia.  We  remember  it  once  very  dis- 
tinctly in  a  person  who  had  died  of  acute 
hepatitis,  but  in  whose  last  hours  there  had 
been  considerable  pulmonary  congestion ;  it 
made  its  appearance  on  the  third  day  alter 
death.  The  state  of  the  eyes  has  been  much 
insisted  upon  by  some  ;  particularly  their  dul- 
ness,  the  shrinking  of  the  cornea*  from  the 
diminution  of  the  aqueous  humour,  and  the 
viscid  mucous  secretion  which  forms  what  is 
called  the  film  of  death ;  but  these  appearances 
may  be  absent  in  real  death,  and  present  be- 
fore life  has  terminated.  Thus  the  eye  is  often 
prominent  and  glittering  after  death  by  carbonic 
acid,  and  by  hydrocyanic  acid. 

The  iris  is  generally  represented  to  be  in  a 
state  of  dilatation.  Winslowf  paid  conside- 
rable attention  to  it,  and  states  that  he  gene- 
rally found  the  pupil  of  a  moderate  size,  often 
much  contracted  but  never  much  dilated. 
WhyttJ  makes  the  same  observation.  The 
fact  appears  to  differ  with  different  animals. 
Thus  in  the  cat  and  pigeon  the  pupil  dilates 
after  death,  while  in  the  rabbit  it  contracts. § 
Our  own  observations  upon  the  human  sub- 
ject incline  us  to  report  the  pupil  a  few  hours 
afier  death  as  in  a  state  midway  between  con- 
traction and  dilatation.  It  is  difficult  to  speak 
with  precision  upon  the  point,  because  that 
-which  would  be  relative  contraction  in  the 
pupil  of  one  person  would  be  dilatation  in 
another,  and  vice  versa.  We  have  known  ob- 
servers confound  immobility  with  dilatation, 
and  to  this  circumstance  we  attribute  the 
common  statement  that  the  pupil  is  dilated 
at  and  after  death.  It  is  evident  that  if  we 
admit  that  the  contraction  and  dilatation  de- 
pend upon  predominant  action  of  the  lon- 
gitudinal or  of  the  circular  fibres,  we  ought 
to  expect  in  the  death  of  the  part  neither  the 
one  condition  nor  the  other;  but  as  the  con- 
tractility of  this  as  of  other  muscular  pail* 
may  survive  the  cessation  of  the  central  func- 
tions, eitlier  set  of  fibres  may  prevail  for  a 
time.  It  must  be  remembered  however  that  con- 
traction of  the  iris  may  depend  upoa  a  cause 
altogether  different  from  contraction  of  its 
fibres,  viz.  congestion  of  blood  in  its  tissue, 
which  is  said  to  have  some  analogy  to  the 
erectile.  M.  Uenard  states  that  in  some  ex- 
periments upon  dead  bodies  instituted  for  the 
purpose  of  ascertaining  the  effects  of  com- 
pression of  the  diaphragm  upwards  by  tin- 
development  of  gas  in  the  abdomen,  found 

*  Louis  fancied  that  this  sign  was  invariable. 

t  Op.  cit. 

$  On  the  Vitnl  and  other  Involuntary  Motions  of 
Animals,  p.  12!). 

§  Mayo's  Outlines  of  Physiology, .  p.  292,  Jd 
edit. 


808 


DEATH. 


that  it  occasioned  "  refoulement  vers  la  tete 
de  la  portion  fluide  du  sang  qui  est  contenu 
dans  1'oreillette  droite,  et  par  suite,  repletion, 
tumefaction  des  veines  du  cou,  de  la  face, 
de  1'encephale,  suintement,  exsudation  sereuse 
ou  sanguinolente  par  les  porosites,  les  extre- 
mites  des  reseaux  capillaires;  quelquefois 
aussi,  par  suite  de  ce  reflux  dans  les  reseaux 
capillaires,  resserrement  de  la  pupille,  reple- 
tion, distension,  saillie  des  yeux,  qui  etaient 
d'  abord  ternes  et  relaches,  &c.  &c."* 

M.  Villermef  has  described  an  appearance 
of  the  hand  which  he  considers  characteristic 
of  death.  He  says  that  when  dissolution  has 
taken  place  the  ringers  are  brought  together 
and  slightly  bent,  but  that  the  thumb  is  co- 
vered by  them,  being  always  found  in  the 
hollow  of  the  hand  directed  towards  the  root 
of  the  little  finger.  The  phalanges  of  the 
thumb  are  extended  upon  one  another,  but 
the  first  is  flexed  upon  the  metacarpal  bone. 
Villerme  states  that  he  had  often  noticed  this 
appearance  in  dead  bodies  on  fields  of  battle 
and  in  hospitals,  but  that  he  had  never  at- 
tached any  importance  to  it  as  a  sign  of  death, 
till  his  attention  was  directed  to  its  value  by 
M.  Breschet.  We  have  often  confirmed  the 
truth  of  Villerme's  description  by  our  own 
observations,  particularly  in  hospital  cases, 
before  the  bodies  have  been  subjected  to  the 
straightening  processes  of  the  attendants  upon 
the  dead.  When  the  appearance  has  been 
wanting,  we  have  had  reason  to  suspect  that  it 
had  been  removed  by  force. 

The  last  sign  to  be  spoken  of  is  the  altered 
colour  of  the  surface,  presenting  lividities  of 
various  extent.  They  may  occur  in  spots  or  in 
circumscribed  patches,  but  more  frequently 
they  take  the  form  of  an  irregular  suffusion  of. 
a  pale  violet,  or  a  dull  reddish  hue.  They 
always  occupy  the  depending  parts,  and  are 
most  intense  where  the  skin  hangs  loose,  as  in 
the  scrotum,  the  penis,  and  the  labia.  They 
have  also  a  direct  ratio  with  the  suddenness 
of  the  death,  the  quantity  of  blood  in  the 
system,  and  its  tendency  to  continue  fluid. 
Their  presence  indicates  that  gravitation  has 
either  subdued  the  capillary  forces,  or  has  come 
into  play  after  the  cessation  of  the  latter.  But 
they  may  occur  during  life.  We  have  often 
noticed  that  the  livor  of  the  skin  in  bronchitic 
affections  is  more  intense  in  the  back  and 
the  sides,  and  is  even  confined  to  these  parts. 
There  can  be  no  doubt  that  congestions  in  the 
parenchyma  of  the  lungs  are  often  dependent 
upon  position.  The  questions  that  arise  out 
of  these  appearances  have  more  to  do  with  the 
cause  of  death  than  with  the  reality  of  this 
occurrence.  When  circumscribed,  they  may  be 
confounded  with  ecchymoses  resulting  from 
violence.  To  enter  upon  the  discrimination  of 
these  conditions  would  engage  us  in  a  dis- 
cussion far  too  lengthened  for  this  article, 
which  has  already  exceeded  its  limits;  we 

*  Considerations  sur  FOuverture  des  Cadavres, 
p.  88. 

t  Ann.  d'Hyg.  t.  iv.  p.  420. 


must  content  ourselves  with  referring  to  me- 
dico-legal treatises  and  to  an  extremely  valu- 
able paper  by  Dr.  Christison  in  the  Edinburgh 
Medical  and  Surgical  Journal.* 

W^e  shall  conclude  with  a  brief  abstract  of 
M.  Devergie's  observations  upon  the  know- 
ledge which  we  may  collect  from  the  state  of 
the  body  respecting  the  time  which  has  elapsed 
since  death. 

We  may  suspect  that  the  body  has  been 
dead  from  two  to  twenty  hours  if  there  be 
flexibility,  elasticity,  heat,  and  contractility ; 
from  ten  hours  to  three  days,  if  there  be  rigi- 
dity of  the  joints,  pitting  of  the  soft  parts, 
the  natural  colour  of  the  skin,  loss  of  animal 
heat,  and  no  contraction  under  electric  stimu- 
lus; from  three  to  eight  days,  if  there  be 
flexibility  (after  rigidity)  and  no  contractility  ; 
from  five  to  twelve  days,  if  the  soft  parts  are 
puffed,  elastic,  and  shining.  After  the  twelfth 
day  there  is  usually  a  separation  of  the  epi- 
dermis, as  well  as  a  green  tint  of  the  ab- 
dominal integuments.t  But  no  certainty  must 
be  attached  to  these  statements;  they  are 
merely  approximative.  The  modifying  in- 
fluence of  external  media  upon  putrefaction  is 
all  but  unbounded.  In  summer  as  much 
alteration  may  take  place  in  five  or  six  hours, 
as  in  eight  or  even  fifteen  days  of  winter. 

BIBLIOGRAPHY.— Hippocrates,  Prasnotionum  Li- 
ber, sect.  i.  Lord  Bacon,  Historia  vitas  et  mortis. 
Lancisi,  Be  subetaneis  mortibus,  4to.  Rom.  1707. 
Winslow,  Dissertatio  an  mortis  inccrta  sint  indicia. 
4to.  Paris,  1740.  Bmhier,  Dissertation  sur  Tincer- 
titnde  des  signes  de  la  mort.  12mo.  Paris,  1742. 
Louis,  Letties  sur  la  certitude  des  signes  de  la  mort. 
12mo.  Paris,  1752.  Sacht,  Oratio  qua  senile  fatum 
inevitabile  necessitate  ex  humani  corp.  mechanis- 
mo  stqui  demonstratur.  4to.  Ultraj.  1729.  Van 
Geuns,  De  morte  corporea  et  causis  moriendi. 
4to.  Lug  A.  Batav.  1761.  (Recr.s  in  Sandir.  Thes. 
vol.  iii.)  Lanye,  Facies  Hippocratica  levi  penicillo 
admnbrata.  8vo.  Jence,  1784.  Ploucquet,  Resp. 
Schmid.  Do  unioa  vera  causa  mortis  proxima. 
4to.  Tubing,  1786.  C.  Himly,  Commentatio  mor- 
tis, historiain,  causas,  et  signa  sistens.  4to.  Go*- 
ting.  1794.  Anschel,  Thanatologia,  sive  in  mortis 
naturam,  causas,  genera  ac  species,  et  diagnosin 
disq.  8vo.  G'otting.  1795.  Ontyd,  De  morte  et 
varia  morendi  ratione.  8vo.  Lvgd.  Bat.  1797. 
Bichat,  R?cherches  sur  la  vie  et  la  mort.  8\  o.  Paris, 
an.  viii.  Ferriar,  Medical  histories  and  reflections. 
Currie,  on  apparent  death,  2d  ed.  8vo.  Lond.  Itil5. 
Chaussier,  Table  des  phenomenes  cadaveriques. 
Adelon,  Diet,  de  Med.  art.  Mort.  Beatty,  Cyclo- 
paedia of  Pract.  Med.  art.  Persons  found  dead. 
Devergie,  Diet,  de  Med.  ct  Chir.  Prat.  art.  Mort. 
R.  B.  Todd,  Cyclop,  of  Pract.  Med.  art.  Pseudo- 
morbid  appearances.  W.  Philip  on  the  nature  of 
sleep  and  death.  M.  Julia  de  Fontenelle,  Recher- 
ches  medico-legales  sur  1'incertilude  des  signes  de 
la  mort,  £c.  1834.  The  systematic  works  of 
Mahon,  Fodere,  Paris,  Smith,  Orfila,  Devergie, 
and  Taylor,  upon  forensic  medicine  ;  and  a  chap- 
ter on  the  causes  of  sudden  death  in  Dr.  Alison's 
Outlines  of  Physiology  and  Pathology. 

(J.  A.  Symonds.) 

*  Vol.  xxxi.  p.  248.  See  also  an  able  article 
upon  pseudo-morbid  appearances  by  Dr.  R.  B.Todd 
in  the  Cyclopaedia  of  Practical  Medicine. 

t  Op.  cit. 


ANALYTICAL     INDEX 


TO    THE 


FIRST     VOLUME. 


ABDOMEN  (in  anatomy  generally)  i 
Abdomen  (human  anatomy),  2 
walls  and  regions  of  the,  2 
structures  composing  the  walls,  4 
skin,  3* 

superficial  fascia,  S* 
muscles  and  their  aponeuroses,  4* 
obliquus  extern  us,  4* 
obliquus  internus,  6 
cremaster,  6 

transversalis  abdominis,  7 
rectus  abdominis,  8 
pyramidalis,  1O 
quadratus  lumborum,  10 
psoas  magnus,  10 
parvus,  1 1 
iliacus  interims,  11 
fascia  transversalis,  and 
fascia  iliaca,  11 

sub-peritoneal  cellular  tissue,  13 
fascia  propria  of  the  hernial  sac,  13 

septum  crurale,  13 
Peritoneum,  13 

vessels  and  nerves  of  the  abdominal  walls,  arteries,  14 

veins,  15 
lymphatics,  16 
nerves,  iti 

physiological  action  of  the  abdominal  parietes,  16 
abdominal  cavity,  18  (see  also  Cavity) 
Absorption,  20 

description  of  the  absorbent  system,  20 
question  of  venous  absorption  considered,  24 
mode  in  which  the  absorbents  act,  28 
cutaneous  absorption,  31 

specific  uses  of  the  different  parts  of  the  absorbent 
system,  and  the  relation  which  that  system  bears 
to  the  other  vital  functions,  32 
Acalephce  (class  of  invertebrate  animals),  35 
division  of  the  class,  36 
as  proposed  by  M.  Lesson,  3? 
locomotion  and  organs,  37 
motility  and  sensation,  40 
digestion,  41 
circulation,  43 
respiration,  44 
secretion,  45 
generation,  45 

geographical  distribution,  46 
Acids,  animal,  47 

Acrita  (primary  division  of  the  animal  kingdom),  47 
Adhesion,  49 
Adipocere,  55 
Adipose  tissue,  56 

pathological  conditions  of— inflammation,  61 
haemorrhage,  62 
excessive  deposition,  62 
extreme  diminution,  62 
adipose  sarcoma,  63 
steatoma,  63 
lipoma,  63 
melanosis,  64 
Age,  64 

growth,  65 
maturity,  76 
old  age  (decay),  77 
Albino,  83 
Albumen,  88 
VOL.   I. 


Amphibia  (a  class  of  vertebrate  animals),  90 

divisions,  91 

osteology,  91 

muscular  system,  95 

organs  of  digestion,  95 

lymphatic  and  lacteal  system,  9<5 

sanguiferous  system,  96 

respiration,  98 

nervous  system,  100 

organ  of  vision,  101 

organ  of  hearing,  101 

organ  of  smell,  102 

organ  of  taste,  102 

dermal  or  tegumentary  system,  102 

transpiration  and  secretion,  104 

restoration  of  lost  parts,  104 

reproduction,  105 

metamorphosis,  106 
Animal  kingdom,  107 

Divisions.— First  sub-kingdom 

i    Polygaftrica,  108 

2.  Porifera,  108 

8.  Polypifera,  108 

4.  Acalephae,  108 

5.  Echinodermata,  109 

Second  sub-kingdom 

6.  Entozoa,  109 

7.  Rotifera,  109 

8.  Cirrhopoda,  110 

9.  Annelida,  110 

10.  Myriapoda,  1 10 

11.  Insecta,  110 

12.  Arachnida,  111 

13.  Crustacea,  ill 

Third  sub-kingdom 

14.  Tunicata,  112 

15.  Conchifera,  112 

16.  Gasteropoda,  112 

17.  Pteropoda,  113 

18.  Cephalopoda,  114 

19.  Pisces,  114 

20.  Amphibia,  115 

21.  Reptilia,  111 

22.  Aves,  116 

23.  Mammalia,  117 
summary,  117 

Animal,  118 

compajison  of  the  organic  and  inorganic  world*,  in 

physical  qualities  and  elementary  composition, 

118 

size,  113 

chemical  composition,  118 

consistence,  119 

elementary  particles,  120 

duration,  121 

generation,  121 
actions  of  unorganized  and  of  organized  bodies,  Hi 

origin,  122 

preservation,  122 

modifications  (ages),  123 

cessation  of  action  (death),  123 
comparison  of  vegetables  and  animils,  I :» 

general  physical  qualities  and  material  or  chemi- 
cal composition,  124 

organic  composition  (textures),  l  >s 

vital   manifestations  or  actions  of  veeclaMcs  and 
animals  (generally),  12? 

3  G 


810 


ANALYTICAL  INDEX. 


minimal  (continued.) 

(particularly),  origin,  129 
nutrition,  130 
digestion,  132 
respiration,  132 
circulation,  133 
secretions,  135 
heat,  136 
light,  136 
electricity,  137 
motion  and  sensation,  137 
comparison  of  animals  with  one  another,  139 

physical  qualities  and  material    constitution  of 

animals,  139 
form,  139 
structure,  140 
actions  of  animals,  141 
absorption,  142 
circulation,  143 
assimilation,  144 
sensibility,  144 
locomotion,  145 
reproduction,  145 
Ankle,  region  of  the,  147 
skin,  147 

subcutaneous  cellular  tissue,  148 
fascia,  148 
tendons,  149 
muscles,  150 
arteries,  150 
veins,  151 
lymphatics,  151 
nerves,  151 
Ankle,  joint  of  the,  151 
bones — tibia,  151 
fibula,  151 
astragalus,  152 
ligaments,  152 
synovial  membrane,  153 

mechanism  and  function  of  the  ankle-joint,  153 
Ankle-joint,  abnormal  condition  of  the,  154 
accidents  affecting  the  tendons,  154 
ligaments,  164 
bones,  155 

luxation  of  the  tibia  inwards,  155 
complete  luxation  of  the  tibia  inwards  compli- 
cated with  a  simple  fracture  of  the  fibula,  156 
luxation  of  the  tibia  outwards,  complicated  with 
simple  fracture  of  one  or  both  of  the  mal- 
leoli,  158 

luxation  of  the  tibia  and  fibula  forwards,  and 
also  luxation  of  these  bones  backwards  from 
the  articular  pulley  of  the  astragalus  without 
fracture,  159 

complete  luxation  of  the  tibia  forwards  from  the 
articular  part  of  the  astragalus,  complicated 
with  a  simple  fracture  of  the  fibula,  159 
partial  luxation  of  the  tibia  forwards,  with  sim- 
ple fracture  of  one  or  both  of  the  malleoli,  160 
partial  luxation  forwards  of  the  tibia  at  the  ex- 
ternal ankle,  with  fracture  of  the  fibula  near 
the  malleolus,  161 
luxation  of  the  bones  backwards  at  the  ankle-joint, 

162 
morbid  anatomy,  162 

acute  inflammation  of  the  synovial  membrane,  162 
chronic  disease,  163 

Annelida,  (class  of  invertebrate  animals),  164 
divisions,  165 

external  conformation,  166 
sensation,  167 
nervous  system,  168 
organs  of  digestion,   168    • 
circulation,  169 
respiration,  170 
generation,  171 
reproduction,  172 
Anus,  173 

muscles  and  fasciae,  175 

sphincter  ani  cutaneus,  176 
sphincter  ani  internus,  176 
ischio-rectal  space,  177 
obturator  fascia,  177 
transversi  perinaei  muscles,   177 
levatores  ani,  17» 
ischio-coccygcei  muscles,  179 
rectum,  179 
abnormal  condition  of  the  anus  and  neighbouring 

parts,   182 

congenital  malformations,  182 
morbid  conditions,  183 
syphilis,   183 
cancer,  184 
excrescences,  184 
prolapsus  ani,  184 
fissure,  185 
contraction,  185 
haemorrhoids,  185 
fistula  in  ano,  1S6 
Aorta,   187 

arch  of  the,  188 
thoracic  aorta,  189 
abdominal  aorta,  189 


Aorta,  (continued.) 
development,  190 
anomalies,  190 
diseased  conditions,  191 
branches  of  the  aorta:— I.  branches  arising  from  the 

arch,  192 

right  anterior  or  inferior  coronary  artery,  192 

left  superior  or  posterior  coronary  artery,  192 

IT.  branches  of  the  thoracic  aorta: — right  bronchial 

artery,  193 

left  bronchial  artery,  193 
oesophaeeal  arteries,  193 
posterior  mediastinal  arteries,  193 
inferior  or  aortic  intercostal  arteries,  193 
anastomoses,  194 

III.  branches  of  the  abdominal  aorta,  1Q4 
phrenic  arteries,  194 
cffiliac  artery,  194 

coronary  artery  of  the  stomach,  19* 
hepatic  artery,  194 
splenic  artery,  195 
superior  mesenteric  artery,  195 
arteries  of  the  small  intestines,  IQ5 
colic  arteries,  195 

right  superior  colic  or  colica  media  artery,  195 
colica  dextra  or  middle  right  colic  artery,  196 
ileo-colic,  ccecal,  or  inferior  right  colic  artery,  196 
inferior  mesenteric  artery,  196 
middle  left  colic  artery,  196 
inferior  left  colic,  196 
superior  haemorrhoidal  artery,  196 
lumbar  arteries,  196 
middle  sacral  artery,  197 

Arachnida,  (a  class  of  invertebrate  animals),  198 
division  of  the  class,  198 
external  covering  or  tegumentary  system,  201 
digestive  system,  202 
circulating  system,  205 
nervous  system,  206 
organs  of  secretion,  208 
apparatus  for  secreting  the  irritating  or  poisonous 

fluid,  208 
apparatus  for  secreting  the  fluid  that  concretes  in  the 

air,  209 
generative  system,  209 

female  generative  system,  211 
copulation,  oviposition,  and  development  of  the 
ova.    Metamorphosis  and  reproduction  of  the 
extremities,  211 

exclusion  or  hatching  of  the  spider,  214 
Arm,  (surgical  anatomy  of  the,)  216 
skin  and  subcutaneous  tissue,  216 
aponeurosis,  21? 
development,  217 
Arm,  (muscles  of  the,)  219 
cpraco-brachialis,  219 
biceps  flexor  cubiti,  219 
brachiaeus  anticus,  219 
triceps  extensor  cubiti,  219 
Artery,  (normal  anatomy,)  220 
anastomoses,  221 
structure  of  arteries,  221 
external  tunic,  £22 
middle  tunic,  222 
internal  tunic,  223 
physical  properties,  224 
Artery,  (pathological  conditions  of,)  226 
wounds  and  injuries  of  arteries,  227 
suppression  of  haemorrhage,  229 
morbid  state  of  arteries.    Aneurism,  230 
circumscribed  false  aneurism,  232 
diffused  aneurism,  237 
traumatic  aneurism,  237 
secondary  haemorrhage,  238 
aneurismal  varix,  241 
varicose  aneurism,  242 
aneurism  by  anastomosis,  242 
Articulata,  (a  division  of  the  animal  kingdom,)  244 
(Subdivisions.) 
Cirripeds,  245 
Annelidans,  245 
Insects,  246 
Arachnidant,  246 
Crustaceans,  246 
Articulation,  246 

(Structures  entering  into  the  composition  of  joints.) 
bone,  247 
cartilage,  247 

(Various  forms  of  articular  cartilage,)  247 
diarthrodial  cartilage,  248 
synarthrodial  cartilage,  249 
fibro-cartilage,  249 
ligaments,  250 
capsular,  25O 
funicular,  451 
elastic,  251 

synovial  membrane,  251 

forms  and  classification  of  the  articulations,  254 
synarthrosis,  254 
suture,  254 

schindylesis,  255 
gomphosis,  255 
amphiarthrosis,  255 


ANALYTICAL  INDEX. 


311 


Articulation,  (continued.) 
diarthrosis,  255 
arthrodia,  256 
enarthrosis,  256 
ginglymus,  256 
dianhrosis  rotatorius,  256 
Asphyxia,  257 
Aces,  265 

divisions,  2fi6 

osteology,  270 

table  of  the  number  of  vertebrae  in  birds,  272 

table  of  the  number  of  toe  phalanges  in  birds,  269 

fossil  bones  of  birds,  2rt9 

myology,  290 

progression  on  land,  297 
climbing,  297 
swimming,  297 
sailing,  297 
diving,  297 
flight,  297 

nervous  system,  organ  of  vision,  SOS 
lachrymal  organs,  307 
organ  of  hearing,  308 
organ  of  taste,  3 1 1 
organs  of  touch, 311 
organs  of  digestion,  311 
digestive  glands,  325 
absorbent  system,  327 

organs  of  circulation,  vascular  system,  heart,  329 
arteries,  332 
veins,  338. 
respiratory  organs,  34 1 

air-passages,  345 
urinary  organs,  34? 
peculiar  secretions,  349 
tegumentary  system,  349 

development  of  feathers,  351 
organs  of  generation,  male,  353 
female  organs  of  generation,  355 
Axilla,  (surgical  anatomy,)  338 
Axillary  artery,  363 
relations,  363 
branches,  363 

Back,  region  of  the,  surgical  anatomy,  36; 
integuments,  367 
subcutaneous  cellular  tissue,  36? 
nerves,  368 
lymphatics,  368 
Mack,  muscles  of  the,  363 
first  layer,  369 
second  layer,  370 
third  layer,  371 
fourth  layer,  371 
fifth  layer,  372 
sixth  layer,  373 
Bile,  374 

biliary  calculi  or  gall-stones,  376 
Bladder  in  anatomy,  376 
Bladder  of  urine  (normal  anatomy),  376 
urinary  bladder  in  man,  377 
shape,  377 

organization  of  the  bladder,  386 
arteries,  386 
veins,  386 
lymphatics,  387 
nerves,  387 

Bladder,  abnormal  anatomy  of  the  urinary,  389 
congenital  conditions,  389 
numerical  changes,  389 
absence, 389 
plurality,  390 
septa 

extrpphy  or  extroTersion,  391 
oersistance  of  the  urachus,  393 
acquired  changes,  393 

sacculi  or  cysts,  393 
changes  of  capacity,  394 
decrease,  394 
increase,  395 
introversion,  395 
hernia,  395 
inflammation,  396 
idiopathic  softening,  397 
rupture,  398 
fistulas,  398 

haemorrhage  from  the  bladder,  401 
fungous  tumours,  401 
varices,  402 

scirrhus  and  cancer,  402 
paralysis,  408 
spasm,  403 
Blood,  404 

physical  qualities,  404 
globules,  404 

table  of  the  diameter  of  the  globules  of  the  blood,  407 
chemical  composition  of  the  blood,  410 
table  of  the  solid  and  fluid  parts  of  the  blood,  412 
in  the  human  male,  412 

female,  412 

phenomena  of  coagulation,  4 13 
analysis  of  the  crassamentum  (fibrine),  413 
arterial  blood,  414 
venous  blood,  414 


Blood,  morbid  conditions  of  the,  415 
excess  in  quantity,  416 
deficiency,  4  KJ 
different  relations  of  the  solid  and  fluid  parts  to  one 

Another,  4l»> 
specific  gravity,  416 
table  of  specific   gravities    under   several    forms    <>l 

disease,  417 


specific  gravity  of  the  serum,  4  is 
of  the  fibrine  and  red  particles,  418 


temperature,  418 

alterations  of  the  fibrine,  418 

imperfect  coagulation,  418 

buffy  coat,  419 

polypi,  420 

albumen,  422 

haematosine,  422 

oil,  422 

saline  constituents,  423 

state  of  the,  in  inflammation,  423 

in  fever,  424 

in  scurvy,  425 

in  jaundice,  425 

In  disease  of  the  kidney,  426 

in  diabetes,  427 

in  cholera,  427 

in  chlorosis,  428 

in  melanosis,  428 
Bone,  430 

physical  properties  and  intimate  structure  of  bone  in 
man,  430 

shape,  430 

periosteum  and  medulla  and  the  organization  ot 

bone  as  part  of  the  living  system,  433 
chemical  composition,  437 
its  peculiarities  in  other  animals,  438 

Fishes,  438 

Amphibia,  438 

Birds,  438 

Mammalia,  438 
Bone,  pathological  conditions  of,  438 

Class  l.  Diseases  of  the  osseous  system,  439 

rickets,  440 

fragilitas,44l 

mollities,  442 
Class  2.  Inflammation,  443 

adhesion,  444 

suppuration,  448 

ulceration,  450 

mortification,  453 

necrosis,  453 

scrofula,  454 

syphilis,  454 
Class  3.  Structural  diseases,  457 

spina  vencosa,  457 

exostosis,  458 

osteo-sarcoma,  460 

cancer,  463 

fungus  hae  mat  odes,  463 

bloody  cellulated  tumour  within  bones,  464 
Brachial  or  Humeral  Artery,  465 
relations,  465 
branches,  465 

superior  profunda,  465 
•  inferior  profunda,  466 

anastomotica  magna,  466 

anastomoses,  467 
Brain,  467 
Bursce  Mucosce,  467 

subcutaneous  or  superficial  bursse,  46? 
deep  bursae,  467 
deep  vesicular  bursae,  467 
deep  vaginal  bursae,  468 
structure,  469 
contents,  469 
function,  469 
development,  469 

pathological  conditions  of  the  burs«  mucosae,  469 
Carnivora,  skeleton,  471 
muscular  system,  477 
digestive  organs,  477 
chyliferous  system,  479 
organs  of  circulation,  479 
organs  of  respiration,  480 
nervous  system,  480 

organ  of  sight,  480 

organ  of  hearing,  4flO 

organ  of  smell,  481 

organ  of  taste,  48 1 
secretions.    The  urine,  481 
generative  system. 

male  organs,  482 

female  organs,  482 
Carotid  artery,  482 

the  primitive  carotid,  483 

relations  of  the  trunk  of  the  pi  imitive  carotid,  483 
the  external  carotid,  484 

branches  of  the  external  carotid,  485 

anterior  branches  of  the  external  carotid,  49* 
posterior  branches,  487 
the  internal  carotid  artery,  490 
Cartilage,   495 

temporary,  495 


812 


ANALYTICAL  INDEX. 


Cartilage,  (continued.) 
permanent,  495 

organization,  496 
accidental  cartilage,  497 
pathological  conditions,  499 
Cavity. 

abdominal  cavity,  500 

epigastric  region,  502 

umbilical  region,  504 

hypogastric  region,  505 
abnormal  conditions  of  the  abdominal  cavity,  507 

congenital  malformation  of  the  abdominal  pa- 
rietes,  608 

morbid  conditions  of  the  abdominal  parietes,  509 

congenital  malformation  of  the  abdominal  cavity, 

509 

Cellular  tissue,  509 
arrangement,  509 
couimon  cellular  membrane,  510 
special  cellular  membrane,  510 
nerves  of,  511 
chemical  composition,  511 
properties,  511 
morbid  conditions  of  the  cellular  tissue,  5  IS 

inflammation,  513 

infiltration,  515 

induration,  516 

morbid  growths,  516 

foreign  bodies,  516 

Cephalopoda,  (a  class  of  invertebrate  animals),  517 
definition,  517 
characters  of  the  chtss,  517 
division  of  the  clags  into  orders,  517 

Order  1.  Tetrabranchiala,  518 

Order  II.  Dibranchiata,  519 
subdivision  of  the  orders,  519 
internal  cartilaginous  parts  or  endo-skeleton,  524 
locomotive  system,  525 
digestive  system,  531 
organs  of  circulation,  538 
respiratory  organs,  542 
nervous  system,  54? 

organs  of  sense,  551 

organ  of  sight,  r>5i 

organ  of  hearing,  554 

organ  of  smell,  554 

organ  of  touch,  555 
generative  system,  555 
Cerumen,  562 
Cervical  neroes,  562 
Cetacea,  (a  class  of  the  mammiferous  vertebrate  animals), 

562 

'  divisions,  563 
organs  of  motion,  564 
digestive  organs,  571 
organs  of  circulation,  576 
organs  of  respiration,  579 
urinary  organs,  581 
nervous  system,  682 

organ  of  sightr-584 

organ  of  hearing,  586 

organ  of  taste,  589 

organ  of  touch,  589 
organs  of  generation,  591 

Cheiroptera,  (a  class  of  the  mammiferous  vertebrate  ani- 
mals), 594 
osteology,  595 
organs  of  the  senses,  598 

organ  of  vision,  598 

organ  of  hearing,  598 

organ  of  touch,  599 

organ  of  smell,  599 
digestive  organs,  599 
organs  of  generation,  600 

Chyliferous  system,  (comparative  anatomy),  600 
Chyliferous  system,  (human  anatomy,)  See  Lacteal,  60" 
Cicatrix,  602 
Cilia,  606 

in  Infusoria,  606 

in  Polypi  and  Sponges,  609 

ciliary  motion  of  the  ova  of  Polypi  and  Sponges,  613 

mtheAcalephffi,  613 

in  the  Actiniae,   614 

in  the  Echinodermatata,  615 

in  the  Annelida, 

in  the  Mollusca,  619 

of  the  ciliary  motion  of  the  embryo  of  the  Mollusca, 

626 
phenomena  of  the  ciliary  motion  in  the  Vertebrata, 

Reptiles,  628 

Birds,  631 

Mammalia,  631 
summary  of  the  animals  in  which  the  ciliary  motion 

has  been  discovered,  632 
organs  or  parts  of  the  body  in  which  the  ciliary  motion 

has  been  ascertained  to  exist,  632 
of  the  ciliary  motion  in  the  embryo,  633 
figure,    structure,   and  arrangement  of  the  cilia  in 

general,  633 

of  the  appearance  of  the  cilia  in  motion,  634 
duration  of  the  ciliary  motion  after  death    and  in 

separated 'parts,  634 


Circulation,  638 

effects  of  external  agents  on  the  ciliary  motion,  634 
effects  of  inflammation,  635 
of  the  power  by  which  the  cilia  are  moved,  635 
of  the  motion  caused  in  fluids  by  the  cilia,  636 
course  of  the  blood  in  Man,  639 
proofs  of  the  circulation,  640 
course  of  the  blood  in  the  foetus,  640 
course  of  the  blood  in  various  animals,  641 
in  warm-blooded  animals,  642 
in  cold-blooded  vertebrated  animals,  642 

Reptiles,  64.3 

portal  circulation  in  Reptiles,  646 
in  Fishes,  646 

portal  circulation  in  Fishes,  647 
course  of  the  blood  in  invertebrate  animals,  648 
Mollusca,  648 
Articulata,  650 
Annelida,  650 
Insects,  651 
Crustacea,  652 
Arachnida,  652 
Zoophytes,  653 
Entozoa,  654 
Acalephae,  654 
Infusoria,  654 
Polypi,  654 
phenomena  of  the  circulation  and  powers  moving  the 

blood,  655 

flow  of  the  blood  through  the  heart,  655 
phenomena  of  the  arterial  circulation,  658 

velocity  of  the  blood  in  different  arteries,  659 
force  of  the  blood  in  the  arteries  and  force 

of  the  heart,  661 
arterial  pulse,  663 
vital  properties  of  the  arteries,  664 
influence  of  the  vital  powers  of  the  arteries 

on  the  circulation,  667 
phenomena  of  capillary  circulation,  669 

structure  and  distribution  of  the  capillary  vessels, 

669 
properties  of  the  capillary  vessels,  and  their  in- 

flutnce  on  the  circulation,  671 
phenomena  of  the  venous  circulation,  674 
relation  of  the  circulation   to  other  functions, 

1.  to  respiration,  675 

2.  circulation  within  the  cranium,  678 

3.  influence  of  varieties    in  the  distribution  of 

arteries  and  veins  upon  the  circulation,  678 

4.  influence  of  the  nervous  system  upon  the  circu- 

lation, 679 

Cirrhopoda,  a  class  of  invertebrate  animals,  683 
division,  684 

external  coverings  and  organs  of  support,  684 
locomotion,  687 
motility  and  sensation,  688 
circulation,  689 
respiration,  689 
secretion,  690 
icproduction,  690 

development  of  the  egg  and  young,  <J92 
Cirronosis,  694 
Colloid,  see  Scirrhus. 

Conchifera,  (a  class  of  invertebrate  animals),  694 
division,  695 
organs  of  digestion,  695 
organs  of  circulation,  698 
organs  of  respiration,  699 
organs  of  generation,  700 
organs  of  motion,  700 
nervous  system,  704 
skin  and  its  appendages,  705 
siphons,  707 
shell,  707 

general  structure,  707 
hinge,  707 
ligament,  708 
cardinal  edge,  708 
surfaces  of  the  valves,  710 
classification  of  the  conchifera,J14 
Contractility,  716 

I.  irritability,  717 

II.  vital  power  or  property  of  irritability,  7-19 

III.  conditions  necessary  to  the  contractile  powers, 

IV.  laws  regulating  the  vital  powers  of  contractile 
parts,  723 

Cranium,  (comparative  anatomy,)  724 
human  anatomy,  725 
bones  of  the  cranium,  7'26> 

sphenoid  bone,  726 

frontal  bone,  728 
Cranium,  ethmoid  bone,  730 
occipital  bone,  731 
temporal  bone,  733 
parietal  bone,  735 

articulations  of  the  cranial  bones,  (sutures,)  736 
surfaces  of  the  cranium  (external  surface),  737 

internal  surface,  738 

correspondence  of  the  external  and  internal  sur- 
faces, 739 

measurements  of  the  cranium,  739 
analogy  between  the  cranium  and  a  vertebra,  740 


ANALYTICAL  INDIA. 


813 


Cranium,  (continued.) 

and  several  vertebrae,  74O 
development  of  the  cranial  bones,  741 
mechanical  adaptation  of  the  cranium,  74« 
abnormal  conditions  of  the  cranium,  744 
acephalia,  744 
fiK-rplialocele,  744 
insufficient  evolution,  744 
thinness  of  the  parietes  ^hydroccphalus,)  744 
ossa  Wormiana,  744 
persistence  of  certain  sutures,  744 
want  of  symmetry,  744 
obliteration  of  the  sutures,  745 
changes  from  age,  743 
extraordinary  thickening,  746 
exostosis,  745 

extraordinary  thinness,  745 
i-rt'fcts  of  inflammation,  745 
u.llit'sion,  7-16 
caries,  746 
necrosis,  -346 
medullary  sarcoma,  746 

Cranium  (regions  and  muscles  of  the),   division  into  re- 
gions, 746 

occipito-frontal  region,  747 
integument,  747 
subcutaneous  tissue,  747 
muscles,  747 

occipita-frontalis,  747 
corrugator  supercilli,  748 
nerves,  748 
arteries,   74ft 
veins,  741 
lymphatics,  749 
pericranium,  749 
lemporo-paiietal  region,  749 
temporal  fascia,  7*9 
muscles,  7.9 
nerves,  749 
arteries,  749 
veins,  749 
lymphatics,  749 
pericranium,  749 
Crutacea,  750 

tablt-  of  the  arrangement  of  the  class,  751 
I  I.  skin  or  tegumemary  skeleton,  and  organs  of  loco- 
motion, 752 
moult  or  process  of  renovation  of  the  tegumen- 

tary  skeleton,  759 
reproduction  of  extremities,  760 
§  2.  apparatus  of  sensation,  A.  nervous  system,  762 

B.  organs  of  the  senses, 
767 

touch,  767 
tase,  768 
smell,  768 
hearing,  768 
sight,  769 


Crustacea,  (continued.) 

1 3.  apparatus  of  nutrition,  771 

A.  apparatus  of  digestion  ;  mouth, 

and  its  appendages,  771 
intestinal  canal,  773 
mouth,  GBsophckgus,  stomach,  ?  n 
biliary  system,  775 

B.  blood  and  circulation,  77i 
heart  and  arteries,  776 

venous  sinuses,  777 
branchio  cardiac  (efferent)  vessel,  777 
entrance  of  the  blood  into  the  heart,  777 
respiration,  777 
generation,  788 
ovum,  785 

incubation  and  developm«nt,  784 
Cyit,  787 

first  class  of  cysts,  788 
second  class,  789 
Death,  791 

molecular  death,  791 

destruction  of  the  tissues,  791 
arrest  of  the  fluid  of  nutrition,  704 
retention  of  fluid  in  the  tissues,  792 
depravation  of  the  fluid  of  nutrition,  70« 
extinction  of  irritability,  793 
systemic  death,  794 

syncope  by  asphyxia,  79* 

by  nervous  lesion,  794 

by  injuries  of  the  heart  itself,  795 

of  other  organ*,  795 
by  mental  emotion,  796 
by  hemorrhage,  796 
by  poisons,  797 
by  cold  and  lightning,  797 
by  inanition,  797 
by  disease,  797 
by  old  age,  798 

signs  of  approaching  death,  799 
delirium,  799 

death-struggle  or  agony,  800 
relaxation  of  the  muscles,  800 
weakness  of  voice,  800 
decline  of  the  circulation,  801 
state  of  the  respiration,  801 
loss  of  heat,  801 
state  of  the  secretion,  801 
facie s  Hippocratica,  &c.  8O2 
signs  of  actual  death,  803 

of  extinction  of  the  vital  function!,  803 
changes  in  the  tissues,  804 

changes  in  the  external  appearance  of  the  body, 
807 


END   OF   VOL.    f. 


MARCHANT,  PRINTER,  INGRAM-COURT,  I'ENCUURCH-STREET. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY, 
BERKELEY 


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